Cast Conference 2009

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Cc'2009 - International Conference - CAST COMPOSITES'2009 - October 11-14, 2009 - Kocierz, POLAND

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INTErNATIONAL CONfErENCE

CAST COMPOSITES'2009October 11-14, 2009Kocierz, POland

CC’2009

organized byFoundry Research Institute, Krakow, Poland•

co-organizer byWorld Foundry Organization•Polish Foundrymen Organization•Malopolskie Centre of Innovative Technology and Materials (MCITiM)•Motor Transport Institute, Warsaw, Poland •

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Editorial staff: Natalia Sobczak, Jerzy J. Sobczak, Rajiv Asthana, Joanna Madej, Marta Konieczna

Computer typesetting: Agnieszka Fiutowska, Patrycja Ruminska

Cover design: ENTER gRAF, Krakow

© Copyright by Foundry Research Institute - Krakow 2009 All rights reserved

ISBN 978-83-88770-42-5

Edited by: Foundry Research Institute73 Zakopianska Str., 30-418 Krakow, Polandwww.iod.krakow.pl

Printing:Foundry Research Institute

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Content

International Scientific Committee Local Organizing Committee

PROGRaMProgram of conference

aBSTRaCTS

ABSTRACTS OF ORAL PRESENTATIONS (sorted day by day)

DAY 1Processing Session (P-1) Interfaces Session (I-1) Characterization Session (C-1)

DAY 2Processing (P-2) Interfaces Session (I-2) Special Session devoted to the 3-D Al-CF composites (S-1)

DAY 3general Session

POSTER SESSIOn (PS)

ABSTRACTS OF POSTER PRESENTATIONS Porous ceramic preforms for production of metal-ceramic composites by infiltration method

Changes of properties of aluminium matrix composite reinforced with SiC particles after multiple remelting

Al3Ti particles reinforced aluminium matrix composites for plastic working

Microstructure differences of composites reinforced with SiC particles

Interaction between liquid titanium and ZrO2-based ceramics

Austempered ductile iron – new grade of the first man-made composite

Page

55

152329

394755

105

69

71

73

75

77

79

81

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Wettability and reactivity in Al/MgO and Al/MgAl2O4 systems

Interaction between molten Inconel 740 alloy and oxide ceramics

Experimental complex for investigations of high-temperature capillarity phenomena

Interaction between molten aluminium and cobalt oxide single crystal

Effect of carbon coating on wetting and bonding of Al alloys with Al2O3 substrates

Wetting and reactivity between molten aluminum and zinc oxide

Theoretical aspects of ordered porosity metallic materials produced by unidirectional solidification of gas saturated melt

Investigation of composition and thermodynamic characteristics of Al-based casting composite materials

The influence of heat treatment of metallic melts (HTM) on structure and properties of solidified hypo-autectic silumines

graphite to 304SS braze joining by active metal brazing technique - Improvement of mechanical property

Interface analysis of YSZ - to - metal brazes fabricated with reactive filler metals

Surface treatment of the aluminium matrix composite materials with concentrated electric discharge in magnetic field

LIST OF AUTHORSLIST OF PARTICIPANTS

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International Scientific Committee

Local Organizing Committee

Rajiv aSTHana (USA)alan lindsay GREER (UK)Werner HUFEnBaCH (Germany)Jolanta JanCZaK-RUSCH (Switzerland)Krzysztof J. KURZYdlOWSKI (Poland) luis Filipe MalHEIROS (Portugal)Sergej MIlEJKO (Russia)Keisaku OGI (Japan)alberto PaSSEROnE (Italy)Pradeep Kumar ROHaTGI (USA)Peter SCHUMaCHER (Austria)Robert SInGER (Germany)Mrityunjay SInGH (USA)Jozef SlEZIOna (Poland)Jerzy Jozef SOBCZaK (Poland)natalia SOBCZaK (Poland)Jozef Szczepan SUCHY (Poland)

natalia SOBCZaK - ChairMarta HOMaMarta KOnIECZnaartur KUdYBaJoanna MadEJRafał NOWAKPatrycja RUMInSKaaleksandra SIEWIOREK

(alphabetically)

(alphabetically)

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PROGRAM OF CONFERENCE

Sunday11 October 2009

Monday12 October 2009

Tuesday13 October 2009

Wednesday14 October 2009

Registration14.00-18.00

Registration and breakfast7.30-9.30

Breakfast7.30-9.30

Breakfast7.30-8.30

Opening 9.30-9.45

departure to Krakow

9.00

Processing P-1

Session9.45-11.25

ProcessingP-2

Session9.30-11.00

Coffee break11.25-12.00


InterfacesI-1

Session12.00-13.10

Interfaces I-2

Session11.30-13.00

Final Session 11.00-13.30 and closing ceremony

Lunch13.10-14.30

Lunch13.00-14.30

Lunch 13.30-14.30

CharacterizationC-1

Session14.30-15.40

Special Session devoted to

the 3-d al-CF composites14.30-16.10

Presentation of MCITiM

15.40-16.30


Poster Session15.40-16.50

Poster Session16.10-17.30

Informal dinner18.00-20.00

Banquet19.00

dinner 19.00

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9.45-10.15 (invited) Metal–Ceramic interactions in cast composites – a foundry perspective R. Asthana, N. Sobczak, J.J. Sobczak[P-1.1, page 16]

10.15-10.35Synthesis and characterization of al–based MMCs reinforced with ceramic nanoparticlesA.E. Karantzalis, A. Lekatou, K. Leontaris[P-1.2, page 18]

10.35-10.55aluminum castings reinforced with ceramic preforms of graded structure by pressure infiltration P. Darlak, N. Sobczak, J.J. Sobczak, A. Kudyba, M. Homa[P-1.3, page 19]

10.55-11.25 (invited)analysis of the solidification and properties of plaster cast al based compositesP. Egizabal, A. garcia Romero, A. Torregaray[P-1.4, page 21]

11.25-12.00 Coffee break

Monday, 12 October 2009Chairing: J.J. Sobczak, J.S. Suchy Session P-1: Processing

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12.00-12.30 (invited) Thermodynamics and kinetics approachS. Agathopoulos[I-1.1, page 24]

12.30-12.50TEM characterization of reaction products of liquid al and alTi6 with mulliteJ. Morgiel, N. Sobczak, M. Pomorska[I-1.2, page 25]

12.50-13.10arrangement of particle distribution in al-Si/SiCp composite by means of lorentz force L. Drenchev, J.J. Sobczak, W. Lesniewski, P. Wieliczko, P. Darlak[I-1.3, page 27]

13.10-14.30 Lunch

14.30–15.00 (invited)High-resolution X-ray computed tomography of composite materialsA. Egbert [C-1.1, page 30]

15.00-15.20Wear characteristics of traditional and new generation brake discsD. Rudnik, R. Michalski, A. Wojciechowski, J.J. Sobczak, P. Darlak[C-1.2, page 31]

Monday, 12 October 2009 Chairing: R. Asthana, P. EpizabalSession I-1: Interfaces

Monday, 12 October 2009 Chairing: L. Drenchev, J.W. KaczmarSession C-1: Characterization

,

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15.20-15.40Heterophase composites - production, properties and structureA. Dolata-grosz[C-1.3, page 33]

15.40-16.30Presentation of Małopolskie Centre of Innovative Technologies and Materials

MCITiM: facility and activities •N. Sobczak, M. Homa, M. Lech-grega, M. Zybura, P. Zieba,FP7 as strategic tool for creating the R&D policy in the field of foundry •industry - information about recently open calls M. Latallo-Anulewicz

[C-1.4, page 35]

16.30-18.00Coffee Break & Poster Session

19.00 Banquet

9.30-10.00 (invited) alFa composites - the state of the art and future perspectives R.M. Purgert, J.J. Sobczak, N. Sobczak, P. Darlak[C-1.1, page 40]

10.00-10.20Selected material characteristics of ceramic preforms infiltrated by alSi9Mg alloy K. Pietrzak, D. Rudnik, A. Wojciechowski, W. Przetakiewicz, J.J. Sobczak, P. Lasota, P. Darlak[C-1.2, page 42]

10.20-10.40Microstructure of SaFFIl fiber preformsJ.W. Kaczmar, K. Naplocha, K. Pietrzak, M. Pomorska, J. Morgiel[C-1.3, page 44]

Tuesday, 13 October 2009 Chairing: A. Passerone, P. ZiebaSession P-2: Processing

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10.40-11.00Cast metal matrix composites reinforced with carbide phasesM. Cholewa, M. Kondracki[C-1.4, page 46]

11.00-11.30 Coffee break

11.30 – 12.00 (invited)Interaction between molten metals and ceramic materials A. Passerone, M.L. Muolo, F. Valenza[I-1.1, page 48]

12.00-12.20Effect of oxidation and testing conditions on wetting behavior and interfaces in al/ni system A. Siewiorek, A. Kudyba, N. Sobczak[I-1.2, page 49]

12.20-12.40Microstructure of the reaction product region formed due to the high tem-perature contact of liquid aluminium and ZnO single crystalJ. Wojewoda-Budka, N. Sobczak, J. Morgiel, R. Nowak[I-1.3, page 51]

12.40-13.00Wettability and reactivity between liquid aluminium and Y2O3-containing ce-ramicsN. Sobczak, R. Nowak, E. Sienicki, L. Stobierski[I-1.4, page 53]

13.00 – 14.30 Lunch

Tuesday, 13 October 2009 Chairing: S. Agathopoulos, J.MorgielSession I-2: Interfaces

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14.30-14.50Textile-reinforced carbon fibre aluminium composites manufactured with gas pressure infiltration methodW. Hufenbach, M. gude, A. Czulak, F. Engelmann, A. Boczkowska[S-1.1, page 56]

14.50-15.10Carbon long fibre reinforced al-matrix composites by high pressure die casting H. Ballmes, C.A. Rottmair, R.F. Singer[S-1.2, page 58] 15.10-15.30Investigations of the interfaces between carbon fibres and aluminium alloy matrix in the composites fabricated by pressure infiltration process R. Kozera, A. Dolata-grosz, M. Dyzia, J. Bielinski, A. Broda, A. Boczkowska,M. gude, J. Sleziona, K.J. Kurzydlowski[S-1.4, page 60]

15.30-15.50Factors affecting wettability and infiltration of 3d-CF reinforcement with liquid al-based matrixN. Sobczak, A. Kudyba, A. Siewiorek, J. Sleziona, A. Dolata-grosz, M. Dyzia, R. Kozera, J. Bielinski, A. Boczkowska, K.J. Kurzydlowski, H. Ballmes, C.A. Rottmair, R.F. Singer, M. gude, A. Czulak, F. Engelmann, W. Hufenbach[S-1.5, page 62]

15.50-16.10Modelling of fibres breaking in composites using fractals characteristicsD. Aniszewska, M. Rybaczuk[S-1.6, page 64]

16.10-17.30 Coffee break & Poster Session

19.00 Dinner

Tuesday, 13 October 2009 Chairing: W. Huffenbach, K.J. KurzydlowskiSpecial Session devoted to the 3-D Al-CF composites

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Wednesday, 14 October 2009 Chairing: A. Balinski, N. Sobczak General Session

11.00-11.15 Introduction to the activities of the Foundry Research InstituteJ.J. Sobczak

11.15-11.35advanced techniques for structural characterization at MCITiM M. Faryna

11.35-12.00 The mystery of molten metals: methodological, scientific and practical aspects of high temperature studies of metal/ceramic interactionsN. Sobczak

12.00-13.30 Visit to laboratories of the Foundry Research Institute

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abstracts

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P - 1Processing

P-1.1 (invited)Metal-ceramic interactions in cast composites – a foundry perspectiveR. Asthana, N. Sobczak, J.J. Sobczak

P-1.2Synthesis and characterization of al–based MMCs reinforced with ceramic nanoparticlesA.E. Karantzalis, A. Lekatou, K. Leontaris

P-1.3aluminum castings reinforced with ceramic preforms of graded structure by pressure infiltrationP. Darlak, N. Sobczak, J.J. Sobczak, A. Kudyba, M. Homa

P-1.4 (invited)analysis of the solidification and properties of plaster cast al based compositesP. Egizabal, A. garcia Romero, A. Torregaray

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METal-CERaMIC InTERaCTIOnS In CaSTCOMPOSITES – a FOUndRY PERSPECTIVE

R. Asthana1, N. Sobczak2, J.J. Sobczak2

1Engineering and Technology Department 326 Fryklund Hall, University of Wisconsin-Stout Menomonie, WI 54751, USA

2Foundry Research Institute, 73 Zakopianska Str., 30-418 Krakow, Poland

Keywords: processing, metal-ceramic, interaction

Cast composites have matured to a level that component designers now routi-nely consider these composites to be a promising family of engineered materials for niche applications. Intricately interwoven into this confidence is the designer’s trust in the composite manufacturer’s ability to deliver the material whose limited history of use and dependability relative to that of established and dependable conventional industrial mate-rials such as steels is matched only by the promise and potential of a much larger envelop of designable properties and performance flexibility. Implicit in the capability to synthesize such a versatile family of materials is the technical know-how to develop and perfect re-liable casting technology, scientific know-how to judiciously select the composite’s consti-tuents, and reproducibly control and tailor the geometric, morphological, compositional, and other key features of the synthesized material at the macro and micro-scales, all of which critically determine the material’s performance.

This paper provides an applied, foundry-intensive overview of one key micro-structural feature of cast composites - the ceramic/metal interface - and the interactions between ceramic reinforcement and metallic matrices that govern interface development. Practical examples of metal/ceramic interactions drawn from microstructural observa-tions of cast composites (C/Al, SiC/Al, Al2O3/Ni, Al2O3/Cu etc.) synthesized using liquid metal infiltration, stir-casting, and crystal growth techniques have been presented to de-monstrate the exquisite diversity of form and feature of the interface that such interactions spawn, and the commonalty and unity inherent in the diversity manifested in the interface microstructure. The purpose is to stimulate discussion and applied research on ceramic/metal interfaces in cast composites by focusing on technical issues that aid in establi-shing rapprochement between the practical concerns of the materials technologist and science-based concerns of the materials researcher. The practical examples and pheno-mena will be drawn chiefly from cast composites containing micrometer-scale continuous and discontinuous reinforcement, but remarks concerning metal-matrix nanocomposites shall also be presented.

P-1.1 (invited)

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Fig. 1. (a) Ni-plated SiC in Al, (b) Cu-coated SiC in Al, (c) eutectic Cr on sapphire in sapphire/NiAl(Cr), (d) reaction layer in sapphire/NiAl(Yb), (e),(f) & (g) surface of sapphire extracted from NiAl(Yb) matrix, (h) & (i) C fiber infiltration with Cu-Ti

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SYnTHESIS and CHaRaCTERISaTIOn OF al–BaSEd MMCs REInFORCEd WITH CERaMIC nanOPaRTIClES

A.E. Karantzalis, A. Lekatou, K. Leontaris

Laboratory of Applied Metallurgy, Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Hellas, greece

Keywords: processing, Al-matrix, nanoparticles

Novel Al matrix composites have been produced by the successful incorporation of TiC and WC nano-particles into molten aluminum through the use of wetting enhance-ment agents prior to casting. Multi-walled carbon nanototubes were also tested as poten-tial reinforcement using the same manufacturing technique. Their incorporation proved significantly difficult and only under heavy mechanical stirring conditions.

Examination of the microstructure with optical microscopy revealed that particle clustering at the grain boundaries for the cast products proved to be inevitable, yet me-chanical stirring could improve their overall distribution.

Both TiC and WC showed a grain refining effect on the cast-based composites. Interfacial examination with electron microscopy revealed the presence of reaction pro-ducts. Reactivity was slightly more intensive in the case of WC particles. Primary mecha-nical response assessment by three point bending showed that reinforcement content, particle clustering and porosity are the key factors for the material behaviour.

P-1.2

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P-1.3

alUMInUM CaSTInGS REInFORCEd WITH CERaMIC PREFORMS OF GRadEd STRUCTURE BY PRESSURE InFIlTRaTIOn

P. Darlak, N. Sobczak, J.J. Sobczak, A. Kudyba, M. Homa

Foundry Research Institute, 73 Zakopianska Str., 30-418 Krakow, Poland

Keywords: graded ceramic, preforms, pressure infiltration, Al-MMC

The study presents the results of investigations carried out to develop a technolo-gy of the fabrication of metal-ceramic systems characterized by graded structure through application of pressure infiltration which, at present, is the most popular technique for the manufacture of metal matrix composites. It is assumed that in this process external pressure is the main technological parameter. Nevertheless, the correct choice of infiltra-tion process parameters should base on the investigations of interactions taking place in a solid body/liquid body system, which in this particular case is usually a molten metal/ceramic material system. The investigations were carried out using a sessile drop method developed by Foundry Research Institute in Krakow. By this method, the high-tempera-ture wetting kinetics of liquid metals (or alloys) penetrating into the ceramic materials was examined under the conditions of high (10-6 hPa) vacuum. Basing on the results of the in-situ examinations, the ceramic materials satisfying the conditions of high chemical stability and mechanical strength, sufficient for use in the squeeze casting technology, were selected and subjected next to pressure infiltration tests with AlSi12CuMg alloy. The preforms were fabricated from oxides developed by the Institute of glass and Ceramics (ISiC) and from the carbide and nitride materials developed by the Institute of Advanced Manufacturing Technology (IZTW).

Preforms were characterized not only by a non-homogeneous size of gradient but also by differences in its nature and orientation. The methods applied in the fabrication of preforms as well as the results of the investigations of their structure and properties were discussed in [1, 2]. To test the graded infiltration of oxide preforms, two batches of the preforms made from the same, selected earlier, A16Sg material (99.8% Al2O3, 0.03% SiO2, 0.06% Na2O, 0.02% Fe2O3, 0.01% CaO, 0.03% MgO) were prepared. They differed in the technique by which the graded structure was produced.

Trials of pressure infiltration were carried out in a specially designed mould, pla-ced on the table of a PHM-160 hydraulic press. Before infiltration, the preforms were preheated in a chamber furnace and transferred to a hot mould cavity for infiltration. They were poured with molten metal and subjected to infiltration carried out in an „upper variant” with simultaneous squeezing of liquid metal, making castings of 70 mm diameter and 30 mm height. Each casting was next cut in sections normal and parallel to the direction of infiltration (done under local conditions of IZTW) to disclose the preform location (espe-cially when examining the infiltration of preforms fabricated by IZTW and AgH), make preliminary visual assessment of the preform deformation degree (macrostructural analy-sis), and determine the distribution of selected properties on a cross-section of the ready composite sample (with electrical conductivity and hardness taken as examples).

Basing on the results of macrostructural examinations it has been concluded that the fabricated composite materials reinforced with preforms of a graded structure

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were characterized by high susceptibility to molten metal infiltration. Irrespective of the preform location in mould, the preform shape, or the direction of molten metal infiltration, the pore distribution gradient has never been an obstacle to infiltration penetrating the entire preform volume. In all cases of preform infiltration, the structural continuity of both ceramic and metallic phases has been obtained (Fig. 1). Each type of the ceramic graded preform was characterized by high stability in contact with the selected molten AlSi12CuMg alloy.

Fig. 1. Example of the structure of metal matrix composite reinforced with graded oxide preform A16SG (ISiC) fabricated by infiltration with AlSi12CuMg alloy

Additionally, it has been observed that the use of graded preforms fabricated by ISiC from the selected A16Sg oxide gave composite materials characterized by optimum properties. Castings locally reinforced with preforms of this type offered the most homo-geneous distribution of porosity within each graded layer and were free from the defects like preform deformation, cracks, or residual porosity.

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P-1.4 (invited)

analYSIS OF THE SOlIdIFICaTIOn and PROPERTIES OF PlaSTER CaST al-BaSEd COMPOSITES

P. Egizabal1, A. garcía Romero2, A. Torregaray3

1Fundación Inasmet, Paseo Mikeletegi 2, 20009 Donostia 2 UPV/EHU, Escuela Univ. de Ingeniería Técnica Minera, 48902 Baracaldo3UPV/EHU, Dpto.Ing. Minera, Met. y Ciencia de Materiales, 48012 Bilbao

Keywords: MMCs, lost wax, plaster casting, solidification

The present work deals with the plaster casting process of MMCs. Feeding and filling aspects and the influence of the solidification rate on the properties of the final ca-stings were studied in order to take advantage of the combination of properties of MMCs and lost wax processes.

1. Introduction Lost wax processes are interesting for the production of MMC components. High

added value castings with intricate geometries and good surface quality may be obtained [1-2]. This work presents aspects related to the optimization of the plaster casting process for the production of MMC components, influence of solidification rate and tensile proper-ties obtained.

2. Production of components A commercial MMC F3S.20S produced by the company Duralcan has been used

to carry out the work. Two part moulds were produced with different filling designs and plaster materials. The optimization of the process has been focused on two main aspects. The design of the feeding and filling system and the study of methods to accelerate soli-dification [3-5]. The final castings were produced with the following parameters:

Mould material: MCP15 plaster from R&R (UK)Plaster/water ratio: 80/100Mould temperature: 200ºCCasting temperature: 730ºC

Different strategies were tried to decrease the solidification rate of the composite material such as the incorporation of chillers and refrigerated copper tubes within the mould and the use of liquid nitrogen. Solidification rates were measured by embedding some thermocouples in four different locations in the plaster mould. The data was collec-ted and processed by a Novacast ATAS software and represented in the corresponding solidification curves.

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TERMOPaR 3

500520540560580600620640660680

-100 900 1900 2900

time (s)

tem

per

atu

re (

ºC)

Te-P-S4-01Te-P-S4-03Te-P-S4-04Te-P-S4-05-RTe-P-S4-06-RTe-P-S4-07Te-P-S4-08-R

Fig. 2. Detail of the thermocouples located within the plaster mould and the obtained solidification curves

3. Results Following the solidification rates obtained with different methods are shown1) Solidifcation rate without any cooling system 0.5-0.8ºC/s.2) Solidification rate with a more permeable plaster 2.0ºC/s.3) Solidification rate by using water cooled copper tubes 2.2ºC/s.4) Solidification rate with liquid N2 1.6ºC/s.Solidification rates of F3S.20S alloy in plaster moulds.

Subsequently samples were cast with the 1) and 3) conditions to measure their me-chanical properties and to compare them with the unreinforced alloy:

Rm (MPa) R0,2 (MPa) E (GPa) Elong. (%)

F3S.20S 145 90 75 0.5-1

F3S.20Sartificialcooling

150 110 80 1-1.8

Unreinforced alloy 120 85 70 2.8

Table 2. Mechanical properties of F3S.20S

4. ReferencesS. Kennerknecht: “MMC studies via the investment casting process”. 1. Cast Metal Matrix Composites, Hitchiner Manufacturing Co, Inc.2. DURALCAN Composites for gravity Castings, Property Data, Alcan. Composite casting guidelines, Du-3. ralcan.M.K. Surappa, Aluminium matrix composites: Challenges and opportunities. 4. U.T.S. Pillai, J. Duszczyk, L. Katgerman, Casting characteristics of high silicon added F3S.20S. 5.

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I - 1InterfaceSI-1.1 (invited)

Thermodynamics and kinetics approachS. Agathopoulos

I-1.2TEM characterization of reaction products of liquid al and alTi6 with mulliteJ. Morgiel, N. Sobczak, M. Pomorska

I-1.3arrangement of particle distribution in al-Si/SiCp composite by means of lorentz force L. Drenchev, J.J. Sobczak, W. Lesniewski, P. Wieliczko, P. Darlak

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I-1.1 (invited)

THERMOdYnaMICS and KInETICS aPPROaCH

S. Agathopoulos

Department of Materials Science and Engineering, University of Ioannina gR – 451 10 Ioannina, greece

Keywords: metal/ceramic bonding, interface, wettability

Joining of ceramics should be approached with respect to the particular applica-tion that the joint is aimed at. In case of biomaterials, joining process should preserve bio-activity, mechanical properties and structure of parent materials. In biomedicine, several complex structures inevitably require joining of two or more phases in a unique structure in the same device, such as in coatings, dental crowns, etc. In fact, composite biomate-rials indicate the naturally predicted direction of biomaterials design.

This work aims to indicate design and study of joining as an important perspecti-ve of bioceramics synthesis and manufacturing.

Direct joining at elevated temperatures, having both joint parts at solid state, usu-ally results in poor adhesion due to slow solid diffusion and often limited contacting areas, while prolong exposition of parent materials to high temperatures may jeopardize their biocompatibility. The use of a third auxiliary phase, necessarily made of biocompatible non-toxic elements, which can melt between the parent work-pieces during joining, can shorten joining processing time (from few seconds to couple of minutes). Nevertheless, its presence introduces at least one new phase in the composite material. Moreover, the formation of liquid phase does not ensure by itself the increase of contact areas between the two parent work pieces. In the case of use of noble metals, their chemical inertness can result in poor wetting. Reactive elements, such as Ti, are usually incorporated to improve wettability but in case of noble metals this can be achieved only under special conditions. The features of reaction zone (composition, crystallinity, brittleness), formed after solidification, crucially determine the mechanical stability of resultant joints.

Biocompatible glasses, whose properties can be potentially regulated by adju-sting their composition, can be also used as auxiliary intermediate phases, because they usually wet well and exhibit good chemical affinity to both Ti and hydroxyapatite-like ce-ramics.

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I-1.2

TEM CHaRaCTERIZaTIOn OF REaCTIOn PROdUCTS OF lIQUId al and alTi6 WITH MUllITE

J. Morgiel1, N. Sobczak2, M. Pomorska1

1Institute of Metallurgy and Materials Science, Polish Academy of Sciences 25 Reymonta Str., 30-059 Krakow, Poland


Keywords: interfaces, TEM, Al/mullite

Introduction Among many ceramic materials mullite presents an attractive combination of good me-

chanical properties and relatively low price. The presence of covalent Al-O and Si-O bonding in this material allows it to withstand high temperatures without shape change, what made it renowned as “Hessian crucibles” in the Middle Ages. Therefore, the mullite might be considered as a material of choice for reinforcement of performs for cast metal matrix composites (MMC).

The infiltration of ceramic performs with liquid metal under pressure in squeeze casting process allows to obtain near net shape products and thus to avoid or at least to reduce the very difficult final surface mechanical polishing [1]. The above approach needs the ceramic performs that do not change their dimensions during processing caused from either their mechanical we-akening or chemical degradation due to aggressive attack of reactive liquid matrix. The production processes of such MMC could be controlled both by modification of the melt composition and ela-boration of optimum time-temperature squeeze casting procedures.

The gathered up to now data indicate that at high temperature, mullite is well wetted by aluminium, while alloying addition like silicon or copper decrease it only slightly [2]. The effect of melt alloying on wetting is also dependent on experimental conditions, i.e. heating the AlTi6 being in contact with mullite substrate (CH – contact heating) results in the formation of thinner zone of reaction products, while removal of surface oxide by squeezing the same alloy from the capillarity (CP – capillarity purification) increased its range [3]. The further progress in understanding pro-cesses taking place during wetting might be gained through investigation of the phases formed as result of reaction between melt and the ceramic substrate. The preliminary analysis performed using scanning electron microscopy indicated that the contact of liquid aluminium with mullite cau-ses precipitation of alumina [3]. However, the limited spatial resolution of this technique prevented identification of other products of much smaller size.

Therefore, the aim of the experiment described in present paper was to investigate the microstructure and phase composition of the Al and AlTi6 with mullite reaction zone using transmis-sion electron microscopy guaranteeing much higher resolution.

Experimental The mullite compacts obtained from the Institute of glass and Ceramics from Warsaw

were used as substrates for Al and AlTi6 wetting experiments at 1273 K for 2 hours. The wetting by aluminium was executed relying on “contact heating” (CH), while the one with AlTi6 on “capillarity purification” (CP) procedures.

The microstrstructure observations were performed using TECNAI FEg SuperTWIN (200 kV) transmission electron microscope equipped with integrated EDAX microanalysis system. The thin foils were prepared using Quanta 3D focused ion beam (FIB) with Omniprobe lift-out system.

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b

Results

The substrate used in wetting experiments were built of Al6Si2O13 mullite crystallites im-mersed in matrix of amorphous silicon oxide phase (Fig. 1a). The mullite crystallites shapes varied from regular cubs, through columnar to irregular rounded ones. These compacts showed very high density visualized by lack of any larger voids.

The exposure of such substrate to liquid aluminium resulted in formation of broad corruga-ted reaction zone (RZ) products. The microstructure observations revealed that most of the reaction zoneconsistsofirregularα-Al2O3 crystals separated by aluminium channels (Fig. 1b). Deep in the reaction zone, i.e. close to the substrate, some of the channels are also filled with silicon. On the other hand, at the drop/RZ interface a continuous layer of silicon and aluminium-silicon crystallites was formed.

The substitution of aluminium with AlTi6 alloy in wetting experiment produces very similar RZ products microstructure (Fig. 1c). Among the differences one may point to more corrugated shapesofα-Al2O3, which bond directly with the AlTi6 metallic drop and that aside aluminium chan-nels also silicon-titanium ones are also present. Additionally, throughout all RZ a presence of finer titanium precipitates were noted.

The faster dissolution of amorphous silicon matrix in mullite compacts by metallic melt is evidenced by diffused character of RZ/mullite compacts interface, where regular Al6Si2O13 crystal-lites are separated by channels filled with fine crystalline material reach with aluminium, silicon and titanium.

The RZ formed between aluminium and mullite contained less but bigger voids than those formed with AlTi6.

Fig. 1. Microstructure of a) mullite compacts substrate, b) Al/RZ and c) AlTi6/RZ interfaces

SummaryThe simultaneous application of optical, scanning and transmission electron microscopy observa-tions helped to prove that the RZ formed as a result of interaction of liquid Al or AlTi6 alloy consist mostlyofα-Al2O3 separated by aluminium channels. Only deep in the RZ, i.e. away from the drop some of the channels are filled with silicon or silicon-titanium intermetallic phase.

Acknowledgements: The experiments were executed within the project PBZ/II.5.4/2005 finaced by the Ministry of Science and Higher Education of Poland (Task II.5.4: „Investigation of developed nano-structure materials with transmission electron microscopy”).

References

R. Asthana, Solidification Processing of Reinforced Metals, Trans Tech Publications, 1998.1. R.E. Loehman, K.g. Ewsuk, A.P. Tomsia, J. Am. Ceram. Soc., 79[1] (1996), pp. 27-32.2. N. Sobczak, L. Stobierski, M. Ksiazek, W. Radziwill, R. Nowak, A. Kudyba, Ceramika-Polish Ceramic 3. Bullletin, 80 (2000), pp. 831-838.

27


I-1.3

aRRanGEMEnT OF PaRTIClE dISTRIBUTIOn In al-SI/SICP COMPOSITE BY MEanS OF lOREnTZ FORCE

L. Drenchev1, J.J. Sobczak2, W. Lesniewski2, P. Wieliczko2, P. Darlak2

1Institute of Metal Science, Bulgarian Academy of Sciences, 67 Shipchenski Prohod Str., 1574 Sofia, Bulgaria


Keywords: FgMs, composite materials, processing, Lorentz force

Functionally graded Materials (FgMs) present good opportunities to reduce mecha-nical and thermal stress concentration in many structural elements. Thus the development of instruments for micro- and macrostructure design of FgMs is a challenge for the modern industry. This work is devoted to application of Lorentz force (LF) as an instrument for in-situ control of the local composition of particle reinforced metal matrix composites (MMCs). The effects of physical parameters (electrical conductivity, type and size of the particles, current density) and geometrical characteristics (size and shape of MMC ingot) have been investiga-ted. Two types of experiments were carried out. In the first type, the model liquids were transparent electroconductive water solutions of various chemical substances used for purpo-se to observe movement of different phases of a mixture in field of gravity and LF, to establish some basic relations, and to outline potential applications of the technique considered. Al-Si alloys and Al-MMC (AlSi7Mg-10 vol.% SiC particles) as commercially available F3S.10S ma-terial were used in the other experiments in order to reveal the effective tools for control of structure formation in solidifying Al-Si monolithic alloy and Al-Si/SiCp composite. In the tests, the Lorentz force was generated by perpendicular electric and magnetic fields, which lie in a plane perpendicular to gravitational acceleration while the homogeneous magnetic field was induced by permanent magnet. The intensity of magnetic field was 0.3 T in all experiments but the current density varied in dependence of base liquid and magnitude of LF need. Transparent vessel of 0.05 m length, 0.07 m height and 0.01 m thickness was used in the model experiments. This vessel is filled up to 0.04 m from the bottom. Ceramic mold of 0.12 m length, 0.09 m height and 0.02 m thickness was used in case of real composite. The ingots obtained were of 0.1 m x 0.06 m x 0.01 m size. The experiments were conducted with relatively large particles of substance irreso-lvable in the base liquid when the Lorentz field intensity is directed opposite to gravity. Thus, conditions of apparent microgravity were realized. The transparent vessel is placed between poles of the permanent magnet. The current density is between 300 A/m2 and 1500 A/m2.

As example, Figure 1 shows the results of the tests with CuSO4 water solution of density 1100 kg/m3 and rubber pieces of volume about 1 mm3. Without electric field (j = 0) all pieces of rubber were segregated at the upper surface, Fig. 1a). As the electrical field was switched on, the current density was established at 300 A/m2 and the rubber particles started to redistribute at the bottom in a sedimentation process. In this case, the water solution becomed “lighter”, i.e. of lower apparent density, due to the Lorentz field applied. The Lorentz

28


field does not act directly on the particles because they are not electroconductive. The pieces that are at the liquid/air interface (at the very upper surface of the liquid) are subjected to “end-effects” and they stay motionless.

Fig. 1. Sedimentation of light rubber particles in CuSO4 water solution subjected to Lorentz field: a) start position, fL = 0; beginning of the process;

b) after 1 s; c) after 2 s; d) after 3 s; e) after 4 s; f) after 5 s

The results on model liquids have comparetevly good agreement with theoretical calculations and the results on real composites. For real composite melt, the solidification process under conventional conditions (experiment No. 1, Table 1) results in structure that has large content of reinforcing phase at bottom of the ingot, small particle concentration at the middle region and almost zero particle concentration in the upper part of the ingot.

Table 1. Values of parameters used in experiments and calculated densities of Lorentz and gravitational forces for liquid composit F3S.10S (fG=ρg)

The distribution of reinforcing phase, SiCP, is very different when solidification runs in Lorentz field. In the next two experiments, the Lorentz force is directed downward. The electri-cal conductivity of the melt is relatively high whereas the electrical conductivity of SiC is in fact zero. This causes Archimedes force of high value due to Lorentz field, which acts upward. The solid particles of the reinforcing phase begin to float to the upper melt surface. This process is concurrent with solidification and final particle distribution is determined by the relationships of the velocities of these processes and the reinforcing phase can be observed in each region of the ingot. The particles are of smaller size and lower percentage are at the bottom while higher percentage of the particles is observed in the middle region of the ingot. Shrinkage and gas porosity is concentrated predominantly in the top region but small amount of gas bubbles can be observed also in the rest regions of the ingot. A discussion on important relationships demonstrated in real structure formation is given. Some recommendations for practical applications are also made.

Acknowledgments: This work is sponsored by the Ministry of Science and Higher Education of Poland under the project No. PBZ-KBN-114/T08/2004.

a) b) c)

d) e) f)

Experiment Number

j[kA/m2]

S[m2]

Lorentz force, f L

[kN/m3]gravity force, f g

[kN/m3]fL/ f g

1 0 270x10-6 0 25 0

2 320 252x10-6 96 25 3.84

3 580 207x10-6 174 25 6.96

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C - 1CharacterizationC-1.1 (invited)High-resolution X-ray computed tomography of composite materialsA. Egbert

C-1.2Wear characteristics of conventional and new generation brake discs D. Rudnik, R. Michalski, A. Wojciechowski, J.J. Sobczak, P. Darlak

C-1.3Heterpohase composites - production, properties and structureA. Dolata-grosz

C-1.4Presentation of Malopolskie Centre of Innovatie Technologies and Materials:

- MCITiM: facility and activities N. Sobczak, M. Homa, M. Lech-grega, M. Zybura, P. Zieba

- FP7 as a strategic tool for creating the R&d policy in the field of Foundry industry – information about recently opened calls M. Latallo-Anulewicz

30


HIGH-RESOlUTIOn X-RaY COMPUTEd TOMOGRaPHY OF COMPOSITE MaTERIalS

A. Egbert

gE Sensing & Inspection Technologies gmbH (phoenix|x-ray), Niels-Bohr-Str. 7, 31515 Wunstorf, germany

Keywords: nanoCT, high resolution Computed Tomography, 3D micro-analysis

For a wide range of inspection tasks, high resolution X-ray computed tomography (CT) has become a powerful tool. CT systems are applied in failure analysis and in 3D metrology, especially for advanced casting components, and offer a wide expansion of customary two-dimensional X-ray inspection capabilities.

Depending on the sample size and the material, resolutions down to a few micro-meters or even below can be achieved. Internal difference in material, density or porosity within a sample can be visualised and distances or pore volumes can be measured. Once scanned, the three dimensional CT information allows non-destructive visualisation of slices, arbitrary sectional views, pseudo-colour representations and 3D measuring. Furthermore, comparison of the volume data with CAD data (variance analysis, reverse engineering) is possible.

There is a wide range of available CT-systems for 3D-inspection of casting com-ponents and materials: Large scanners are suitable for CT of whole light metal motor blocks, very compact systems are specialised for the high resolution analysis of the mi-crostructure of small samples. The presentation will show nanoCT results produced by the nanotom, the first 180 kV/15 W nanofocus computed tomography system which is tailored to highest-resolution applications with exceptional voxel-resolution down to 500 nm. Furthermore, CT results of the v|tome|x L300, the first CT system with a unipolar 300 kV microfocus tube for high magnification examinations and measurements of high absorbing components, will be shown.

C-1.1 (invited)

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C-1.2

WEaR CHaRaCTERISTICS OF TRadITIOnal and nEW GEnERaTIOn BRaKE dISCS

D. Rudnik1, R. Michalski1, A. Wojciechowski1, J.J. Sobczak2, P. Darlak2

1Motor Transport Institute, 80 Jagiellonska Str., 03-301 Warsaw, Poland2Foundry Research Institute, 73 Zakopianska Str., 30-418 Krakow, Poland

Keywords: MMC composites, reinforcement phase, microstructure

1. Introduction For several years metal matrix composites (MMC) are developed because of their

attractive exploitation properties. The high level of mechanical properties and low weight of products fabricated from MMC are advantageous especially in aerospace and motor industry solutions. Introducing the MMC reinforced by hard particles or fibers, in total volume or locally, results in improvement of ready products mechanical properties [1-3]. ASM Handbook Volume 21: Composites (was published in 2001) [4] is the another one bibliographical position, which it is proper to notice in the composite materials area. This book can be treated as a base data systematizing composite types, their production and also containing many exploitation cha-racteristics of these materials from the point of view of potential and real recommendations for uses in industry. On the other hand a key factor in the successful commercialization of metal matrix composites is the ability to recycle the scrap and used material for reuse as composi-tes. Presented research is focused on the investigations of the wear resistance by the friction of the traditional and composite brake discs.

2. Experimental procedure The brake discs made from: cast iron, metal matrix composites reinforced with

SiC and with fly ash (ALFA composites) in chosen friction-sets (36 brake discs with vario-us brake pads) were tested. The measurements were carried out by means of KRAUSS apparatus, simulating work conditions of brake disc - brake pad set. The tests were con-ducted according with ECE R-90, Appendix 8 (requirements for a front axle). The aim of these investigations was to assess which friction set will be an optimum-solution in a vehicle design.

3. Results and discussion The results of friction wear investigations are presented in Figure 1 (friction coeffi-

cients of cast iron brake discs with various brake pads) and in Figure 2 (friction coefficients of composite brake discs reinforced with SiC or fly-ash and working with various brake pads).

Friction coefficients of cast iron brake discs

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

µ op µ cold µ min µ max

black pads

green pads

red pads

yellow pads

TomexC 14B pads

ADI Fomar F0910 pads

ADI SUTgAZ 5W1Z pads

ADI TomexC 9W9Z pads

OMP pads

semi-metal Mazda pads

PMD pads (USA semi-metal)

JURID-545 pads, 9,5 bar

JURID-545 pads, 12 bar

JURID-545 pads, 15,4 bar

BRESCH pads

JURID-539 pads

TomexC 1022-15 pads, 4 bar

TomexC 1022-9 pads, 0 bar

Firction coefficients of cast iron brake disc

Fig. 1. Comparison of friction coefficients of cast iron brake discs with various brake pads

32


Friction coefficients of composite brake discs

0

0,1

0,2

0,3

0,4

0,5

0,6

µ op µ cold µ min µ max

Alfa - EBC red padsAlfa - OMP padsAlfa - Mazda padsAlfa - EBC green padsAlfa - EBC yellow padsAlfa - Lotus Elise (11,7bar)Alfa - JURID 545 gF pads (9 bar)Alfa - Lotus EliseS20 - EBC green padsS20 - EBC yellow padsS20 - Lotus Elise (8,8 bar)S20 - Lotus EliseS20 - JURID 545 gFS20 - BRESCH ZW-100-EE padsS20 - JURID 545 gF (9 bar)S30 - TomexC 10-23S30 - PMD-591 padsS30 - JURID 539 FF 20 padsS30 - JURID 545 gF pads (9 bar)

Fig. 2. Comparison of friction coefficients of composite brake discs reinforced with SiC or fly-ash and working with various brake pads

Remaining results showing the temperature changes in a fading cycle and in rege-neration cycle (with a cooling) of all investigated brake discs will be presented in an extended form of paper.

The results make possible to formulate that:dynamic investigations on Krauss apparatus showed that if the brake discs are •not ventilated, only the friction-sets consisted of the cast iron brake discs and the investigated brake pads can be used in vehicle brake systems. It is connected with the efficient applying of the brake (µ 0.3) and the not very large wear of the disc (≤0.1mm);lowbrakeefficiency(µ≤0.3),highwearofmaterial(≥0.1mm)andhighworktem-•perature(t≥350°C)wereobservedinthecaseofthefriction-sets:compositebrakediscsandinvestigatedbrakepads;not ventilated composite brake discs are not met the technical requirements and •can not be used in the braking system on a front axle in vehicles of M1 and N1 category;the results allow to ascertain that the pressure decreasing in a brake system and in •consequence the work temperature decreasing and brake discs wear decreasing will make possible the application of composite brake discs, based on Al-alloys, on the passenger cars and delivery vans rear axle.

Firction coefficients of composite brake disc

References

J. Sobczak : Kompozyty metalowe, Instytut Odlewnictwa-Instytut Transportu Samochodowego, Kraków-1. Warszawa 2001, ISBN 83-913045-8-2.A. Wojciechowski, J. Sobczak: Kompozytowe tarcze hamulcowe pojazdow drogowych Instytut Transportu 2. Samochodowego, Warszawa, 2001.D. Rudnik, J. Sobczak: Tloki kompozytowe do silnikow spalinowych, Instytut Transportu Samochodowego, 3. Warszawa, 2001.ASMHandbookVolume21:CompositesPublished2001,1201Pages,Hardbound,ASMInternational;By:4. D.B. Miracle and S.L. Donaldson.

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C-1.3

HETEROPHaSE COMPOSITES - PROdUCTIOn, PROPERTIES and STRUCTURE

A. Dolata-grosz

Silesian University of Technology Faculty of Materials Science and Metallurgy, 8 Krasinskiego Str., 40-019 Katowice

Keywords: processing characterization, properties, Al-MMCs

In recent years aluminium metal matrix composites containing ceramic particles, particularly alumina oxide and silicon carbide have been developed for several applica-tions, including electronic, aerospace and military but first of all in the automotive indu-stries [1]. These composites characterized high specific strength, stiffness, hardness but also lower wear and corrosion resistant [2]. The problem which has never been solved is how to reduce and minimize intensive wear of the machine parts cooperating with such a composite. Among all the technique to fabricate PAMMC, the casting methods with the use of suspension forming processes are one of the most economical and versatile [3, 4]. These composites and problems of shaping theirs structure for many years has been the subject of research works in our country and abroad.

Recent studies on new material solutions refer to the applications of reinforcement with different physicochemical characteristics. Based on an analysis of literature details and the authors’ own investigations conducted at the Silesian University of Technology, it was found that incorporation of different component types into an aluminium alloy matrix, i.e. the application of heterophase reinforcement, offers the possibility of obtaining a com-posite material with better but first of all unconventional properties [5–10]. They affirmed that the application of multiphase reinforcement is a solution which allows expanding, to a large degree, the capacity for designing products' structures and properties. The proper-ties of all composites are correlated with its structure. The composite’s structure always depends on the size, volume fraction and type of the reinforcing phase, as well as the particles' distribution in the matrix. Next the particles' distribution in the matrix is directly related with the technological parameters [7]. Functional properties of these composites are additionally influenced by the mutual quantitative ratio of reinforcing particles of every type [10].

In this paper, the technological aspects, structure, solidification conditions and tribological properties are presented for aluminium casts composites with multipha-se reinforcement. The structure and properties are characterized of composites obta-ined in combined casting and powder metallurgy processes, i.e. Al-FeAl-TiAl-Al2O3, Al-FeAl3-TiC-Al2O3, Al/NiCr-Cr3C2-TiC, Al/Fe-Cu-TiC, as well as of a heterophase alumi-nium alloy based composite with a mixture of alumina oxide (Al2O3) or silicon carbide (SiC) particles in connection with glassy carbon (C) particles. The structure of cast com-posites was characterized by means of light and scanning microscopy methods, and the phase and chemical compositions of the reinforcement were identified by diffraction and X-ray spectroscopy methods. The typical microstructure of the investigated composites using by casting method are presented in Figures 1, 2.

34


Fig. 1. Structure and fracture of Al/Fe(Cu)-TiC composite after gravity casting, SEM

Fig. 2. The structure of heterophase composite reinforced by the mixture of the silicon carbide (50 µm) and amorphous glass carbon particles (100 µm): a) after gravity casting, SEM, b) macro-structure after centrifugal casting, c) outside layer in the composite cast obtained by centrifugal casting, OM, mag. 100x, d) SEM, e) XRD

Acknowledgements: Scientific project funded from means of budget on science in years 2005-2007 as a research project KBN 3 T08D 024 28.

References

KaczmarJ.W.,PietrzakK.,WłosińskiW.:Theproductionandapplicationofmetalmatrixcompositemate-1. rials, Journal of Material Processing Technology, 106 (2000), pp. 58-67.A. Wojciechowski, J. Sobczak: Alternative composite material solution in the frictional connections, Jour-2. nal of KONES Internal Combustion Engines 2003, vol. 10, pp. 3-4.Hashim J., Looney L., Hashim M.S.J: Metal matrix composites: production by the stir casting method, 3. Journal of Material Processing Technology, vol. 92-93, 1999, pp. 1-7. górny Z., Sobczak J.: Metal matrix composites fabricated by the squeeze casting process, Transactions 4. of the Foundry Research Institute, 42, 1995, p. 99.Ames W., Alpas A. T.: Wear mechanism in hybrid composites of graphite-20 pct SiC in A356 aluminium 5. alloy (Al-7pct Si 0,3 pct Mg. Metallurgical and Materials Transactions A, 26A, No 1, 1995, pp. 85-98.ZyskaA.,Braszczyńska-MalikK.N.:StructureoftheAl-(TiB2+Al6. 2O3)p composites produced by in situ method, Composites 4 (2004) 11, pp. 336-340.A.Dolata-Grosz,J.Śleziona,J.Wieczorek:Tribologicalconsequencesofkind,sizeandsegregationof7. heterophasereinforcementdevelopmentbycentrifugalcasting,InżynieriaMateriałowaNo3-4,pp.762-767.A.Dolata-Grosz,M.Dyzia,J.Śleziona:Solidificationcurvesandstructureofheterophasecomposite,8. Archives of Materials Science and Engineering, Vol. 29 Issue 1/2008, pp. 10-15.A.Dolata-Grosz,M.Dyzia,J.Śleziona:StructureandtechnologicalpropertiesofAlSi12–(SiC+Cgp)9. composites, Archives of Foundry Engineering, Vol. 8 Issue 1/2008, pp. 43-46.A.Dolata-Grosz,J.Śleziona,B.Formanek,J.Wieczorek:Al-FeAl-TiAl-Al10. 2O3 composite with hybrid rein-forcement, Elsevier: Journal of Materials Processing Technology, 162-163 (2005), pp. 33-38.

a b c

ed

35


C-1.4

PRESENTATION OF MALOPOLSKIE CENTRE OF INNOVATIVE TECHNOLOGIES AND MATERIALS

MalOPOlSKIE CEnTRE OF InnOVaTIVE TECHnOlOGIES and MaTERIalS (MCITiM): FaCIlITY and aCTIVITIES

N. Sobczak1, M. Homa1, M. Lech-grega2, M. Zybura3,P.Zięba4

1Foundry Research Institute, 73 Zakopianska Str., 30-418 Krakow, Poland2Institute of Non-Ferrous Metals gliwice, Light Metals Division Skawina

9PiłsudskiegoStr.,32-050Skawina,Poland3Institute of Advanced Manufacturing Technology

37A Wroclawska Str., 30-011 Krakow, Poland4Institute of Metallurgy and Materials Science, Polish Academy of Sciences

25 Reymonta Str., 30-059 Krakow, Poland

Keywords: MCITiM, innovative technologies, advanced materials

The presentation will focus on scientific, practical and training activities of the recentlyestablishedScientificandIndustrialConsortiumofMałoposkieCentreofInnova-tive Technologies and Materials (MCITiM) located in Southern Poland (Krakow, Skawina) and associating the following four institutions:

Foundry Research Institute (Coordinator) •Institute of Non-Ferrous Metals gliwice – Light Metals Division Skawina •Institute of Advanced Manufacturing Technology •Institute of Metallurgy and Materials Science of Polish Academy of Sciences.•

Among others, MCITiM is realizing the Project No. POIg.02.02.00-00-012/08 en-titled“RetrofittingtheResearchInfrastructureofMałopolskieCentreofInnovativeTech-nologies and Materials”. The project is co-financed in frame of Operational Programme Innovative Economy 2007–2013 under Priority Axis 2. R&D infrastructure, Measure 2.2 Support for development of research infrastructure of scientific entities. The Project is coordinated by the Foundry Research Institute and it aims at:

development of common research and technical facilities through purchase of new •equipment and/or modernization and retrofitting of the existing units operating at MCITiM, joint execution of research program in the scope of metals processing and materials •engineering, creating possibilities to obtain accreditation for further research and of conditions ne-•cessary to achieve the highest level of research flexibility approved by Polish Centre for Accreditation,

36


extending the scope and quality of services rendered by laboratories both within their •own research program adopted by each institute individually as well as within the program of activities for industry, including small and medium enterprises operating in the metal processing sector, raising the competitiveness of domestic research and development centres,•effective use of public means and resources for research activities through coordi-•nation of actions in order to avoid repetition and doubling of research, experimental facilities and services, increased participation of innovative enterprises, achieved through creation of a new •offer of R&D works and services rendered to these enterprises.

The research and technological facilities of four collaborating institutions will be presented. Special attention will be paid to new equipment and/or modernization and retrofitting of the existing units operating at MCITiM. Successful completing of the aims of Scientific and Industrial Consortium is expectedtomaketheMałopolskieCentreofInnovativeTechnologiesandMaterialswellfitted to carry out the research activities and render broad services to scientific and re-search institutions as well as industrial enterprises operating in various sectors of the industry,notonlyintheregionofMałopolska(SouthPoland),butalsoinallotherpartsofPoland and abroad. To achieve this goal, the long-lasting experience of these institutions, the skills and know-ledge represented by the staff of their workers, and the available laboratory facilities will be combined to form a complementary network which, when strengthened additionally with the purchase of new devices, should bring the expected effect of synergy and enable solving the problems and facing the challenges impossible to be solved and faced under different conditions.

37


FP7 aS a STRaTEGIC TOOl FOR CREaTInG THE R&d POlICY In THE FIEld OF FOUndRY IndUSTRY – InFORMaTIOn aBOUT

RECEnTlY OPEnEd CallS

M. Latallo-Anulewicz


Seven Framework Programme with the budget over 50 billions of EUR is the largest European programme for performing R&D work in whole European industry. It’s aimed at decreasing a distance between EU companies, and companies from the most innovative economies in the world – USA, Japan. FP7 policy defines a number of kinds of R&D concerned projects in specified areas. The foundry production has no specified section in the areas of FP7, so it is very difficult to create a R&D project in the field of foundry, and get it financed. The only areas that could be considered for financing a fo-undry proposals are: “Nanosciences, Nanotechnologies, Materials and New Production Technologies” and “Energy”. That means that foundry industry if concerned on acquiring FP7 funds must create it’s own research policy in the field of “Nanosciences, Nanotech-nologies, Materials and New Production Technologies”, or emerging technologies that will follow to reduce the energy consumption level, which in EU is high if compared to foundries in Japan or USA.

The purpose of this article is to show the possible paths of creating foundry R&D projects and matching them to the criteria of FP7 calls for proposals. The second part of presentation is concerned on the recently opened calls – information about themes, topics, possible project description, etc.

38


39


P - 2PROCESSING P-2.1 (invited)alFa composites - the state of the art and future prespectivesR.M. Purgert, J.J Sobczak, N. Sobczak, P. Darlak, A. Wojciechowski

P-2.2Selected material characteristics of ceramic preforms infiltrated by alSi9Mg alloyK. Pietrzak, D. Rudnik, A. Wojciechowski, W. Przetakiewicz, J.J. Sobczak, P. Lasota, P. Darlak

P-2.3Microstructure of SaFFIl fiber preforms J.W. Kaczmar, K. Naplocha, K. Pietrzak, M. Pomorska, J. Morgiel

P-2.4Cast metal matrix composites reinforced with carbide phasesM. Cholewa, M. Kondracki

40


P-2.1 (invited)

alFa COMPOSITES – THE STaTE OF THE aRT and FUTURE PERSPECTIVES

R.M. Purgert1, J.J. Sobczak2, N. Sobczak2,3, P. Darlak2, A. Wojciechowski3

1Energy Industries of Ohio, Park Center Plaza, Suite 200, 6100 Oak Tree Boulevard, Independence, OH 44131, USA

2Foundry Research Institute, 73 Zakopianska Str., 30-418 Krakow, Poland3Motor Transport Institute, 80 Jagiellonska Str., 03-301 Warsaw, Poland

Keywords: Al-MMC, ALFA, aluminum fly ash, casting, mechanical alloying, pressure infiltration, squeeze casting, tixoforming

Fly ash, being a waste material formed as a result of coal combustion in po-wer and metallurgical plants, needs ecological processing to avoid its dumping at waste grounds or landfills. In view of a very interesting combination of physical and chemical properties, and from the economical and ecological standpoints, fly ash may be a very attractive material as a reinforcing phase in metal matrix composites. Fly ash mainly contains elements, like oxygen, silicon, aluminum, iron, calcium, magnesium, sodium, potassium,andtitanium;thecontentoftheseelementsvariesfromseveraluptoseveraldozen percent. The research carried out over many years by the Foundry Research Institute-Cracow in cooperation with Energy Industries of Ohio-Cleveland, University of Wiscon-sin-Milwaukee and Motor Transport Institute-Warsaw has demonstrated the applicability of fly ash as a reinforcing material for aluminum alloys. Recently, a family of aluminum alloys containing fly ash, named ALFA (Aluminum Fly Ash) composites have been deve-loped by different casting methods (e.g. Fig. 1). The use of fly ash as a filler or reinforcement for Al-MMCs is very desirable from an environmental standpoint and as innovative solution to produce light-weight and low-cost engineering materials, particularly important for automotive industry, since ALFA composites may replace currently used DURALCAN composites, which are difficult to machine, as a material for brake disks and pistons for I.C. engines. However, synthesis of ALFA composites by liquid phase routes is difficult due to poor wettability of fly ash by molten Al and Al alloys at industrially important temperatures and its lightweight nature (particularly for hollow spheres). This work summarizes some technological aspects of ALFA composites synthesis in order to demonstrate advantages and disadvantages of selected production methods as well as corresponding properties and possible applications of ALFA composites. From viewpoint of some essential technological problems associated with ap-plication of commonly used casting technique (based on vortex method) for ALFA com-posite synthesis, which are mainly related with difficulties in controlled introduction of required amount of fly ash particles and in the creation of its uniform distribution in the composite structure, the mechanical alloying approach as well as tixoforming, particu-larly coupled with conventional casting techniques, have proven to be potentially one of the best technological solutions for the fabrication of ALFA composites of beneficial combination of physical and mechanical properties.

41


For synthesis of ALFA syntactic foams, the gas pressure and/or squeeze infiltra-tion methods open new possibilities for obtaining a light construction material, sufficient for use in various potential applications, especially for ultra-light parts, which are required to possess a high capacity of damping for all types of energy. The wide family of recently developed ALFA composites may find successful ap-plication as construction materials, mainly for light-weight components in the automotive industry, which should satisfy the requirement of improved mechanical properties, high wear resistance, thermal shock resistance, good dimensional stability, and rational eco-nomy of their fabrication.

Fig. 1. Tensile strength of ALFA composites produced by different methods:Hbook - handbook's data; MKE - University of Wisconsin, Milwaukee; Australia - University of

Melbourne; PMF - Precision Metal Forming Co.; TAC - Thompson Aluminum Casting Co.; Poland - Foundry Research Institute, Cracow; Madison - University of Wisconsin, Madison; WE - Wiscon-

sin Energy; DP&L - Dayton Power and Light Power Plants

42


P-2.2

SElECTEd MaTERIal CHaRaCTERISTICS OF CERaMIC PREFORMS InFIlTRaTEd BY alSi9Mg allOY

K. Pietrzak1, D. Rudnik1, A. Wojciechowski1, W. Przetakiewicz1, J.J. Sobczak2, P. Lasota1, P. Darlak2


Keywords: characterization, Al-MMC, ceramic preform, infiltration

1. Introduction The development of production techniques results in increase of ready products abo-

ut optimal useful properties at the low weight and low cost of the fabrication. These factors are very important from the point of view of the safety use as well as environmental protection. Over the recent years dynamic development of the advanced technology of light materials in forms of various ceramic preforms infiltrated with different alloys is observed [1-5]. Modern composites fabricated by means of infiltration methods can be used in various industry areas (especially motorization, aerospace). This fact results in necessity of looking for the quanti-tative relationships in logic sequence: material composition-technology-microstructure-useful properties. This research is concentrated on ceramic preforms infiltrated by AlSi9Mg, their impact strength and quantitative microstructure assessment based on own experience [6].

2. Experimental procedure Ceramic preforms based on the Al2O3 next infiltrated by AlSi9Mg alloy were conduc-

ted to the impact tests in order to determine an influence of the material composition (ceramic/alloy) on the impact resistance. Impact resistance was determined from the formula (1):

where: KC - means an impact resistance, Kz - means a work to be necessary to break or to destruct (to bend) the sample of rectangular intersection (S0) in the notch place.

The investigations of impact energy were carried out by means of vertical impact te-sting machine. All test were performed according with Polish Standard PN-EN 10045-1:1994. Microstructures of infiltrated ceramic preforms were quantitatively assessed within the range of the optical microscopy. The following geometrical microstructure parameters of analyzed objects were determined: area fraction (AA, %), mean chord, (lmean, mm), estimators of relative area measured in two mutually perpendicular directions (NLII , mm-1, NL┴, mm1) and mean free distance(λ,mm).

3. Results and discussion The result of investigations of impact strength for ceramic preforms infiltrated with AlSi9Mg alloy is shown in Figure 2.

(1)

43


y = -4,8831x2+34,792x-52,31R2 = 0,7577

55,5

66,5

77,5

88,5

99,510

3 3,5 4 4,5�-1/2 [1/mm2]

KC100/2 [J/cm2]

0123456789

10

1.5 2.5 3.5 4.5 5.5 6.5

Sample number

Impa

ct s

treng

th K

CV

100/

2 [J

/cm

2]

1.52.53.54.55.56.5

Fig. 1. Impact strength of infiltrated ceramic preforms infiltrated by AlSi9Mg alloy

Fig. 2. Relationship KCV/λ-1/2 for ceramic pre-forms infiltrated by AlSi9Mg alloy

The highest impact strength was obtained for sample 1.5 and lowest impact strength was obtained for sample 3.5. The relationship between impact strength (KCV 100/2) and syn-theticgeometricalmicrostructureparameterformulatedforthesepreforms(asλ-1/2) is shown in Figure 2. Microstructures of investigated preforms (as examples) are shown in Figure 3.

conventional light - macro conventional light - magn. 25x phase contrast - magn. 500x

Fig. 3. Microstructures of ceramic preforms infiltrated by AlSi9Mg (sample 1.5 - as the example)

The obtained results of impact strength determination and effects of quantitative microstructure assessment allow to ascertain that it is possible to formulate the synthetic microstructure parameter as λ-1/2 variable, significantly correlated with an impact strength. It was found that the impact strength significantly changes, with this variable, in compliance with the polynomial quadratic. In other words the refinement of the alloy by ceramic areas affects significantly the impact strength of infiltrated preforms.

λ-1/2

ReferencesZ.Sławiński,J.Sobczak,C.Sarnowski,J.Nykiel:Charakterystykieksploatacyjnesilnikówztłokami1. kompozytowymi zbrojonymi lokalnie, Journal of Kones, Combustion engines, vol. 8, No 3-4, 2001, pp. 231-241.SobczakJ.,WojciechowskiA.,RudnikD.,Infiltracjaciśnieniowawwytwarzaniumateriałówkompozyto-2. wych, Studium analityczno-literaturowe, ISBN 978-83-88770-30-2, Instytut Transportu Samochodoweg, Instytut Odlewnictwa, Warszawa, 2008, ISBN978-83-60965-36-8.L.A.Dobrzański,M.Kremzer,A.J.Nowak,A.Nagel:Compositematerialsbasedonporousceramicpre-3. form infiltrated by aluminium alloy, Journal of Achievements in Materials and Manufacturing Engineering, Volume 20, ISUUES 1-2, January-February 2007, pp. 95-98.L.A.Dobrzański,M.Kremzer,A.Nagel:Applicationofpressureinfiltrationtothemanufacturingof4. aluminium matrix composite materials with different reinforcement shape, Journal of Achievements in Materials and Manufacturing Engineering, Volume 24, ISUUES 2, October, 2007, pp. 183-186.D.Rudnik,J.Sobczak:Tłokikompozytowedosilnikówspalinowych,InstytutTransportuSamochodowe-5. go, Warszawa, 2001, ISBN 83-913045-7-4.K. Pietrzak, J. Sobczak, D. Rudnik, N. Sobczak, A. Wojciechowski: Zastosowanie komputerowej analizy 6. obrazuwilościowejoceniemikrostrukturymetalowychmateriałówkompozytowych,IVSeminariumKOMPOZYTY2000,Teoriaipraktyka,Częstochowa2000,pp.191-200.

44


P-2.3

MICROSTRUCTURE OF SaFFIl FIBER PREFORMS

J.W. Kaczmar1, K. Naplocha1, K. Pietrzak2, M. Pomorska3, J. Morgiel3

1Institute of Production Engineering and Automation, Wroclaw University of Technology Wroclaw, Poland

2Institute of Technology of Electronic Materials, Warsaw, Poland3Institute of Metallurgy and Materials Science, PAS, Krakow, Poland

Keywords: characterization, TEM, SEM, SAFFIL preform, Al-MMC

The nano-crystalline Al2O3 with 3-5% SiO2 SaffilTM fibers are used for strengthe-ning of the metal matrix composites (MMC) since the end of 20th century. The problems with machining and especially the final working of MMC stirred interest in near net shape (NNS) technologies, like the one relying on infiltration of ceramic performs with liquid al-loys.

The ceramic preforms are manufactured by mixing of fibers with the binder, for-ming it into a desired shape and firing [1]. The last operation should create stable and relatively strong mechanical joints between fibers necessary to withstand considerable stresses raised during the infiltration with liquid alloys. Otherwise, the heat of liquid metal could cause binder decay followed by breaking connection between individual fibers. Such preform degradation may result in its deformation resulting in production of defected final products.

The investigation of the SaffilTM incorporated MMC are usually focused on their mechanical properties and limited to scanning observations of the ceramic and metallic phases distribution [2]. The more advanced observations including high resolution once are limited to reactions at the fiber surface interface during contact with metallic liquid [3]. However, there is practically no information on bond coating and interfiber joints in fired pre- infiltrated perform microstructure. Therefore, the aim of the present paper was to investigate the process of bond application and firing of the perform with special emphasize on microstructure of the resulting fiber to fiber joining areas.

Experimental The SafillTM fibers in “as received”, coated with the binder prepared on the base of

sodiumwater-glass,aswellasintheshapeoftheperformfiredat1000°Cwereinvestiga-ted. The microstructure observations were performed using scanning (Philips XL30) and transmission microscopy (Tecnai FEg 200 kV). Thin foils were cut from carbon coated fibers and preforms with the application of the focused ion beam (Quanta 3D).

Results The SEM observations showed that SafillTM fibers were characterized by smooth

surface and diameter of a few microns (Fig. 1a). The microstructure investigations of fiber cross-section indicated, that they are built of very fine 20–100 nm size crystallites (Fig. 1b). The boundaries of these crystallites are populated with pores which close only in fiber near surface layer.

45


Fig.1. The SEM image of SaffilTM fibers (a) and its TEM cross-section (b)

Fig. 2. SEM image of the joint formed between SaffilTM fibers with binder in as coated state (a) and after firing (b)

The soaking of the fibers with the liquid binder followed by subsequent drying hel-ped to fix the structure by stabilizing of fiber contact places with binder residues for-ming feather like forms (Fig. 2a). The binder prepared on the base of sodium water-glass decays during processing and drying to hydrated SiO2. In order to produce joints of su-itablestrengththesilicaallotropictransformationofquartzαtotridymiteβtakingplaceat870°Cisrequired.Thelattergoalisachievedbyfiringperformsathightemperature.The latter heat treatment helps to built the strong joints at the fiber contacts and effects on the increasing of the smoothness of the fibers surface as well as the fiber contact area (Fig. 2b).

SummaryThe performed observations using SEM and TEM techniques allowed characterizing

the effect of application of the sodium water glass binder on to the SafillTM fibers at diffe-rent stages of production of ceramic performs.

Acknowledgments: The experiments were executed within the Research Project POIG.01.03.01-14-013/08-00 KomCerMet “Ceramic - Metal Composites and Nanocomposites for the Aerospace and Car Industry”.

ReferencesT.W. Clyne: Encyclopaedia of Materials: Science and Technology, Metal Matrix Composites: Matrices and 1. Processing, A Mortensen (ed.), Elsevier, 2001.H.X. Peng, Z. Fan, J.R.g. Evans, Novel MMC microstructure with tailored distribution of the reinforcing pha-2. se, Journal of Microscopy, 201(2001), pp. 303-338.Z. Zhou, Z. Fan, H.X. Peng, D.X. Li, HREM observations of interface microstructure of a cast AlMgSiBiP-3. b(6262)/Al2O3 composite, Journal of Microscopy, 201(2001), pp.144-152.

46


CaST METal MaTRIX COMPOSITES REInFORCEd WITH CaRBIdE PHaSES

M. Cholewa, M. Kondracki

Silesian University of Technology, Chair of Foundry Engineering, 7 Towarowa Str., 44-100 gliwice, Poland

Keywords: processing, Al-MMC, carbide reinforced, characterization

In this work authors presented collected results from studies concerning the manufacturing of metal matrix composites with reinforcement, mainly carbides, with use of different casting techniques. For composite matrix, different Al-Si alloys were used. Presented results include microstructural studies, quantitative analysis, phases description and their chemical composition. In this part of the work authors characterized the transition zone between the reinforcing particles and metal matrix, showing the possibilities of controlling the properties of the transition zone and type of occurring transition phases.

During the studies two casting methods were used: permanent mould casting and lost wax casting. Authors indicated restrictions and possibilities of these methods in dispersive composite elements reinforced with metallic particles. The characteristic feature of such particles is their physical and chemical reactivity, which deteriorates the rheological properties of the liquid dispersion. Selection of technological parameters for manufacturing and casting was aimed on proper filling of the mould with liquid dispersion.

Both methods of casting were used for manufacturing of elements, which technical application requires special tribological properties, e.g. brake discs. Operating properties of all obtained composites were studied and analyzed. Authors showed the analysis of tribological studies related with the composite structure and type and quantity of the reinforcement used.

P-2.4

47


I - 2InterfacesI-2.1 (nvited)

Interaction between molten metals and ceramic materialsA. Passerone, M.L. Muolo, F. Valenza

I-2.2Effect of oxidation and testing conditions on wetting behavior and interfaces in al/ni systemA. Siewiorek, A. Kudyba, N. Sobczak

I-2.3Microstructure of the reaction product region formed due to the high temperature contact of liquid aluminium and ZnO single crystalJ. Wojewoda-Budka, N. Sobczak, R. Nowak

I-2.4Wettability and reactivity between liquid aluminium and Y2O3-containing ceramicsN. Sobczak, R. Nowak, E. Sienicki, L. Stobierski

48


I-2.1 (invited)

InTERaCTIOn BETWEEn MOlTEn METalS and CERaMIC MaTERIalS

A. Passerone, M.L. Muolo, F. Valenza

IENI-CNR, via de Marini, 6, 16149, genova, Italy

Keywords: interfaces, reactivity, Ni-MMC, borides

The ultra high temperature performance of ceramic-based complex structures mayrequirethedevelopmentofjoiningtechniques;thisinturnrequiresthedefinitionofthe wettability of these materials by various metals over a wide range of compositions and temperatures.

After a short description of the relevant experimental aspects of wettability studies at high temperatures, a discussion will be presented on how these results can be used to derive chemical and structural information on the solid-liquid interactions. Reference will be made mainly to metal-ceramic systems (borides, oxides and carbides), analyzing reactive and non-reactive wetting processes.

In particular, data on the wettability and the interfacial characteristics of systems based on hot-pressed HfB2 ceramics in contact with liquid Ni-X alloys (X = Ti, B) to pro-mote/control wettability will be shown. The experimental data, obtained by sessile drop testsat1500°Cundercarefullycontrolledconditions,willbereportedanddiscussedasa function of time, compositions and ceramic micro-structure characterised by optical microscopy, SEM, EDS and WDS analysis.

In order to provide a basis for the correct interpretation of the experimental re-sults and for the design of optimal brazing alloys, a special emphasis will be given to the need of complex phase diagrams, and in particular on the use of that newly computed for the B-Hf-Ni system.

The morphology of the drop/substrate interfaces, the specific spreading kinetics curves and the influence of interfacial structure on wetting and adhesion (also mecha-nical), as well as the need of further research aiming at optimizing the ceramic/ceramic joining procedures, will be discussed.

49


I-2.2

EFFECT OF OXIdaTIOn and TESTInG COndITIOnS On WETTInG BEHaVIOR and InTERFaCES In al/ni SYSTEM

A. Siewiorek, A. Kudyba, N. Sobczak


Keywords: wettability, oxidation, Al-MMCs, Ni-coating

Deposition of technological coatings on ceramic reinforcement is a widely used method for the improvement of wetting and infiltration of reinforcement with liquid metallic matrix. For Al-MMCs, metallic coatings (e.g. Ni, Cu or Ag) are used. During composite processing by pressure infiltration of liquid matrix into porous ceramic preforms, the last ones should be preheated before contact with liquid matrix. It might cause oxidation of metallic coating, especially under conditions of high oxygen partial pressure (e.g. in air). The study was focused on understanding the effects of testing procedure and surface (both substrate and metal) oxidation on wetting behavior of liquid aluminum on nickel, used as technological coating in practice of Al-MMCs synthesis. Thewettabilitytestswerecarriedoutunderavacuumat700°Cinthemodeldrop/substra-te couples, where the drops were pure aluminium (99.9999%) and the substrates – freshly polished pure Ni (99.8%) plates or those additionally oxidized at 700ºC for 2 hours (Niox). The tests were carried out by a sessile drop method using two different testing procedures: classical sessile drop method coupled with contact heating of the same Al/Ni couple (CH) and capillary purification (CP), where a primary oxide film is removed in situ from the surface of liquid aluminum directly during wettability tests. After wettability tests, cross-sections of the samples were observed using optical microscope in order to identify phase boundaries of Al/Ni and Al/Niox couples and its phase morpho-logy. For 5 min contact, as the most common processing time, liquid aluminium wets both Ni and Nioxsubstratesformingthecontactanglesofθ=26-38º(Table1).Theseresultshaveagoodagreement with our recent studies (Sobczak et al, 2007) showing wetting of NiO single crystal by liquid Al due to the redox reaction resulting in the formation of very fine (nanoscale) Al2O3 precipita-tes. The effect of Al-drop oxidation is somewhat unexpected since for Ni and Niox substrates, the contact angles of oxide-free droplets recorded in CP procedure are about 8-9º higher than tho-se of Al droplets covered with primary oxide film in CH procedure. This effect can be explained by dissimilar contact conditions for these two procedures. Mainly it is caused from the fact that for CH procedure, the interaction takes place during contact heating before reaching the testing tempera-ture while subsequent 5 min contact at that temperature is not sufficient for reaching the equilibrium conditions. This statement has been confirmed experimentally in the 15 min test by CH showing the final contact angle of 23º after ~8 min.

Table 1. Effect of testing conditions on wettability and reactivity in Al/Ni couples.

SubstrateConditions Contact angle

θ[°]

Thickness of IMC-layer

[µm]Procedure Time [min] Pressure [hPa]

Ni CP 5 7.99×10-6-7.69×10-6 38 80

Ni CH 5 7.23×10-6-6.49×10-6 30 65

Niox CP 5 1.11×10-5-9.70×10-6 35 60

Niox CH 5 5.50×10-6-5.18×10-6 26 50

Ni CH 15 4.96×10-7-3.67×10-7 23 ~40

50


Fig. 1. Microstructures of cross-sectioned Al/Ni couple after testing (700°C, 5 min): a) CP; b) CH

Fig. 2. Microstructures of cross-sectioned Al/Niox couple after testing (700°C, 5 min): a) CP; b) CH

Independently on testing conditions and substrate oxidation, the structural observations of the solidified and cross-sectioned sessile drop samples show the presence of Al3Ni precipitates in the drop and a thick intermediate region between the drop and the Ni substrate (Figs. 1,2). The intermediate region is composed of a few continuous layers of intermetallic compounds (IMC). SE-M+EDSanalysishasshownthepresenceofcontinuouslayersofAl3Ni2 (reactively formed during Al/Ni interaction) and Al3Ni (mainly nucleated at the substrate surface during solidification) intermet-talic compounds while the formation of other phases in accordance with Al-Ni phase diagram has not been distinguished. The testing procedure and substrate surface oxidation affect the thickness of IMC layer, showing its smallest thickness and the finest structure for oxidized Al-drop on oxidized Ni substrate (Table 1). The results obtained demonstrate that oxidation of Ni due to preheating of Ni-coated ce-ramic performs in air should not make worse its wetting and infiltration with liquid aluminum. Mo-reover, under certain conditions, the Ni oxidation might have positive effects since the presence of NiO suppresses the growth of IMC interfacial layers while liquid Al reduces NiO oxide to form nanoscale Al2O3 precipitates, resulting in strengthening of material.

Acknowledgements: The study has been financed by the Ministry of Science and Higher Education of Poland in frame of the Polish-German Bilateral Project “3D-textile reinforced Al-matrix composites (3D-CF/Al-MMC) for com-plex stressed components in automobile applications and mechanical engineering”.

51


I-2.3

MICROSTRUCTURE CHaRaCTERISTICS OF THE REaCTIOn PROdUCT REGIOn FORMEd dUE TO THE HIGH TEMPERaTURE COnTaCT OF MOlTEn alUMInUM and ZnO SInGlE CRYSTal

J. Wojewoda-Budka1, N. Sobczak2, J. Morgiel1, R. Nowak2

1Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta Str., 30-059 Krakow, Poland


Keywords:interfaces;TEM,Al/ZnO,Al-Al2O3 composites, C4 structure

Metal-ceramic Al-Al2O3 composites are the group of advanced engineering ma-terials which can be applied in the aviation and ground transport industry. Among many methods they can be also formed by in situ synthesis using the redox reactions between molten aluminum and binary or complex oxides such as SiO2, NiO, CoO, MgAl2O4, mullite or kaolinite. As a result of these reactions the ceramic and metallic phases are created interpenetrating each other leading to the formation of a new material named Co-Conti-nuous-Ceramic-Composite (C4). This extraordinary microstructure is responsible for the properties of the produced composites like a high modulus, high strength, resistance to the thermal shocks and stability of the dimensions. Such a unique combination of desira-ble advantages is practically impossible or much more expensive to obtain by conventio-nal liquid-phase composites manufacturing methods. However, the mechanism of the for-mation of C4 structure is still not clear, particularly the role of processing parameters and type of initial oxide on the type and morphology of the reactively formed oxides [1-4].

Previous study [4] has demonstrated that the Al/ZnO system is a good candidate for in situ synthesis of C4 material in which the reactively formed oxide was characterized by scanning electron microscopy and found to be Al2O3 while its type as well as detailed structure of reaction products region (RPR) were not identified. It was suggested also that the high-temperature interaction between liquid Al and ZnO is affected by the strong evaporation of reactively formed Zn. As a consequence, it contributes to the enhanced transport of Al and Zn to and from the reaction front, respectively, resulting in creating favorite conditions for redox reaction. Moreover, the significant difference in the molar volume of the initial oxide ZnO and the reactively formed Al2O3 coupled with the high so-lubility of zinc in liquid aluminum and its subsequent strong evaporation was concluded to be responsible for cracking the freshly formed Al2O3 interfacial layer thus resulting in the formation of the C4 structure of Al-Al2O3 composite [4].

The aim of this study was to identify, by applying advanced techniques for struc-tural characterization, the type and morphology of alumina phase formed due to the inte-raction between liquid aluminium and ZnO (0001) single crystal.

TheAl/ZnOcouplewasproducedbycontactheatingat700°Cfor40minutes,followed by the holding of the couple at 800ºC for 10 minutes and finally at 1000ºC for 55 minutes under dynamic vacuum. The complementary microstructure examination of the reaction product region was performed using the optical, scanning and transmission electron microscopes.

52


The structural observations confirmed the formation of the reaction product re-gion of ~ 50 µm of thickness extending into the ZnO single crystal substrate. The RPR structure corresponds to the C4 type since it is composed of ceramic Al2O3 and metallic Al(Zn) mutually interpenetrating networks (Fig. 1a).

Further examination using TEM techniques such as energy dispersive spectro-scopy and selected area electron diffraction patterns revealed that the α-Al2O3 type was the main component of the RPR layer. Moreover, the thin columnar layer next to the ZnO substrate was observed. The analysis showed that it corresponds to the δ-Al2O3 phase (Fig. 1b). Most probably, this low-temperature modification of aluminum oxide is formed during cooling of the Al/ZnO couple.

(0001)Zno

250 nm

α-Al2o3 Al(Zn)

1 µm

δ-Al2o3

(0001)Zno

Al(Zn)

α-Al2o3

Fig. 1. TEM microstructure of the reaction product region (RPR) formed due to the Al-ZnO single crystal interaction where two interpenetrating phases Al(Zn) and α-Al2O3 were observed (a). At the

interface of the ZnO/RPR the thin layer of the δ-Al2O3 phase was formed (b)

Acknowledgments: This work has been supported by the Ministry of Science and Higher Education of Poland under Project N N507 272836.

References

DR Clarke (1992) J Am Ceram Soc 75, p. 7391. MC. Breslin, J. Ringnalda, L. Xu, M. Fuler, J. Seeger, gS. Daehn, T. Otani, HL. Fraser (1995) Mat Sci Eng 2. A 195, p.113.Liu W, Koster U (1996) Scripta Mater 35, p. 353. N. Sobczak (2005) Solid State Phenomena 101-102, p. 221.4.

53


I-2.4

WETTaBIlITY and REaCTIVITY BETWEEn lIQUId alUMInUM and Y2O3-COnTaInInG CERaMICS

N. Sobczak1,2, R. Nowak1, E. Sienicki2, L. Stobierski3

1Foundry Research Institute, 73 Zakopianska Str., 30-418 Krakow, Poland2Motor Transport Institute, 80 Jagiellonska Str., Warsaw, Poland

3Academy of Mining and Metallurgy, Krakow, Poland

Keywords: wettability, interfaces, redox reaction, C4 structure, Al-Y2O3, Al-Al2O3

The aim of this work is to study the phenomena affecting wetting behavior and reac-tivity between liquid aluminum and Y2O3-containing ceramic oxides as potential materials for reinforcing aluminum castings by porous performs or dense inserts. The following methods and procedures have been used: 1) classical sessile drop methodcoupledwithcontactheatingoftheAl/oxidecouples(CH);2)dispenseddropmethod(DD) coupled with in situ removal of the primary oxide from the Al surface by squeezing metal throughceramiccapillary;3)dropsucking(DS);4)singleverticalplateprocedure(SVP)and5) sandwiched vertical double plates procedure (SVDP). The tests were done under vacuum at 800-1000ºC for 2h using Al 99.999% and oxide substrates, i.e. polycrystalline - Y2O3

PC and Al2O3

PC;singlecrystals-YAGSC (Y3Al5O12) and YAP (YAlO3). Independently of testing procedure, liquid Al does not wet Y2O3at800°C,whileat900°C itwetsbyDDandat1000°CbyCH(Fig.1).ForY2O3-Al2O3 system, the wettability increases in the order Al2O3Y2O3 YAlO3Y3Al5O12 (Table 1).Structural characterization by optical and scanning electron microscopy (Fig. 2) evidences high reactivity with all Y2O3-containing oxides, resulting in alloying the Al drop with Y and the formation of thick reaction product region (RPR) of the highest thickness for Y2O3 (Table 1). Moreover, for CH and DD procedures, the presence of protuberant metallic layer was noted at the substrate surface between RPR and Y2O3. Visual observation in the SVD test, compared with that of DS test has evidenced that it is squeezed liquid layer (SLL, Fig. 1c) formed due to significant changes in substrate and RPR volume caused by accompanying redox reactions.

Fig. 1. Wettability kinetics in Al/Y2O3PC by different methods at 800-1000ºC

54


Table 1. Contact angles in Al/oxide couples (1000ºC, 2 h, CH)

Parameter Al2O3PC YAgSC (Y3Al5O12) YAPSC (YAlO3) Y2O3

PC

θ(º) 92 64 83 87ΔRPRmax (mm) 0 0.03 0.1 ~2

pc-polycrystalline;sc–singlecrystal

Fig. 2. Microstructure of Al/Y2O3 couples: a) 800ºC, CH; b) 1000ºC, CH; c) SEM top-view (1000ºC, CH); d) 1000ºC, SVP; e-g) 1000ºC, SVDP (e – scheme showing evacuation of gases depending

on different Y2O3 surface roughness, f – polished surface; g – rough surface)

Contrary to DD tests, the RPR in the Al/Y2O3 couples produced by CH has unusual shape (thinner in the central part of the drop) that was explained by different contact condi-tions between the drop and the surface. By applying SVP and SVDP procedures (Figs. 2 d-g), it was demonstrated that the presence of primary oxide film on Al drop in CH and the kinetics ofitsinsituremovalathightemperature(duetoreactionofAl+Al2O3= Al2O) are responsi-ble for the shape of RPR formed. In such a case, the substrate surface roughness plays an important role in the removal of primary oxide from the drop/substrate interface by effective evacuation of gaseous reaction product Al2O outside of the drop/substrate contact. For the Al/Y2O3 couples, scanning electron microscopy observations coupled with EDS analysis show that the RPR presents typical C4 structure (Co-Continuous Ceramic Composite), composed of ternary oxide precipitates (YAg, YAP) surrounded with metallic Al-Y matrix. On the contrary, in case of Al/YAg and Al/YAP couples, the EDS analysis sug-gests the formation of Al2O3. The results of structural characterization imply that interaction in the Al/Y2O3couplesalsomightstartfromtheformationofaluminabyredoxreaction(2Al+Y2O3 = Al2O3 +2Y)andchangetothe(Al-Y)/Al2O3/Y2O3 phase composition. At the next step, the reaction might occur at the unstable Al2O3/Y2O3 interface, leading to the formation of YAg or YAP phases, depending of processing conditions. The results obtained show high reactivity and good wettability of yttria-containing oxide ceramics in contact with liquid Al. It might have negative effect if such materials were used for porous performs or dense inserts serving as a reinforcement of aluminum castings, particularly by pressure infiltration techniques.

Acknowledgements: This work has been sponsored by the Ministry of Science and Higher Educa-tion of Poland under the projects No PBZ-KBN-114/T08/2004 and No NN507450634.

55


S - 1Special session devoted to the 3-D Ai-CF composites

S-1.1Textile-reinforced carbon fibre aluminium composites manufactured with gas pressure infiltration methods W. Hufenbach, M. gude, A. Czulak, F. Engelmann, A. Boczkowska

S-1.2Carbon long fibre reinforced al-matrix composites by high pressure die castingH. Ballmes, C.A. Rottmair, R.F. Singer

S-1.3Investigations of the interfaces between carbon fibres and aluminium alloy matrix in the composites fabricated by pressure infiltration process R. Kozera, A. Dolata-grosz, M. Dyzia, J. Bielinski, A. Broda, A. Boczkowska, M. gude, J. Sleziona, K.J. Kurzydlowski

S-1.4Factors affecting wettability and infiltration of 3d-CF reinforcement with liquid al-based matrix N. Sobczak, A. Kudyba, A. Siewiorek, J. Sleziona, A. Dolata-grosz, M. Dyzia, R. Kozera, J. Bielinski, A. Boczkowska, K.J. Kurzydłowski, H. Ballmes, C.A. Rottmair, R.F. Singer, M. gude, A. Czulak, F. Engelmann, W. Hufenbach

S-1.5Modelling of fibres breaking in composites using fractals characteristicsM. Rybaczuk, D. Aniszewska

56


S-1.1

TEXTIlE-REInFORCEd CaRBOn FIBRE alUMInIUM COMPOSITES ManUFaCTUREd WITH GaS PRESSURE InFIlTRaTIOn METHOdS

W. Hufenbach1, M. gude1, A. Czulak1, F. Engelmann1, A. Boczkowska2

1Institute of Lightweight Structures and Polymer Technology (ILK), Dresden University of Technology, germany

2Division of Materials Design (ZPM), Warsaw University of Technology, Poland

Keywords: textile-reinforced carbon fibre aluminium composites, CF/Al-MMC, metal matrix composites

Textile-reinforced carbon fibre aluminium composites (CF/Al-MMC) with aload-adaptedpropertyprofileofferagreatpotentialforlightweightconstructionofstruc-tural components subjected to high thermo-mechanical loads. However, the use of these new textile-reinforced aluminium composites in engineering requires an in-depth knowl-edgeoftheproductionprocessofcompositematerialsanditsinfluenceonthemicrostruc-ture.

CF/Al-MMChavebeenmanufacturedbygaspressureinfiltration(GPI)usingdif-ferentgraphiteandsteelmoulds.Theinfluenceofthetemperature,theprocesstimeofgaspressure infiltrationprocess (GPI)and thecompositionofdifferentalloysandfibrecoatings on the composite quality have been studied. good mechanical properties of CF/Al composites are highly dominated by the control and enhancement of the interface betweenthecarbonfibresandthealuminiummatrix.Furthereffects,e.g.interfacialreac-tionsoroxideskinscoveringthealuminiummelt,leadtoadegradationofthefibreproper-tiesorratherapoorwettabilityofcarbonfibreswithaluminium.Hence,asuitablechoiceofthealuminiumalloy,fibrecoatingsandtheprocessparameters(e.g.temperature,contacttime and pressure of the surrounding atmosphere) are required.

Generallygoodinfiltrationresultscanbeachievedbyusingnickelcoatedcarbonfibresandmodifiedaluminiumalloys.ThereforewovenfabricsfromTohoTenaxHTS40fibresandamodified226Dcastalloywereused.MicrosectionsofmanufacturedCF/Al-MMC specimenshowalmostcompletewettedfibrefilamentswithonlyafewporesandblowholes (Fig. 1).

Fig. 1. SEM micrograph of a microsection of a CF/Al-MMC plate after GPI-Process, ZPM Warsaw

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Fig. 2. SEM micrograph with EDX measurements of a microsection of a CF/AL-MMC plate after GPI-Process

However, closer inspections by SEM provided evidence of aluminium carbide forma-tion at the interface between carbon fibres and aluminium. Additional EDX measurements at the interfacial region between fibres and matrix detected other phases basically from aluminium, nickel and copper. These cluster-wise phases in the aluminium matrix are located close to the fibre surface and seem to be intermetallic compounds (Fig. 2).

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S-1.2

CaRBOn lOnG FIBRE REInFORCEd al-MaTRIX COMPOSITES BY HIGH PRESSURE dIE CaSTInG

H. Ballmes, C.A. Rottmair, R.F. Singer

Institute of Advanced Materials and Processes, University Erlangen-Nuremberg, germany

Keywords: processing, high pressure die casting, Al-CF

The demand for highly stressed lightweight structures, especially in the area of transportation, machine building and plant engineering, is rising. But just because of the high stresses the use of conventional monolithic materials, like polymers or light metals, is limited. In contrast continuous fibre reinforced composites can tolerate much higher load due to the structure and thus they offer a good opportunity to replace the monolithic materials. The advantages of a metal matrix rather than the usual polymer one consist in higher stiffness and compressive strength, as well as better elevated temperature capa-bilities.

The main problem for a broad utilisation of metal matrix composites is the po-ssibility to manufacture such composites. Established manufacturing processes, which are based on melt infiltration of long fibre performs, are the gas pressure infiltration [1-3] and the squeeze casting process [4-5]. The gas pressure infiltration process allows the manufacture of highly complex components, but in economical aspects this process is not suitable for serial production because of the procedural complexity and the long process cycles. In contrast squeeze casting is characterised by a short cycle time, but the com-plexity of preform and part geometry is limited.

A good alternative for the fabrication process would be the high pressure die casting technology. It offers short cycle times and the possibility to get thin walled and complex part geometries because of the high melt velocity. Previous studies for the ma-nufacture of metal matrix composites by high pressure die casting are almost limited to the infiltration of particle and short fibre preforms.

The aim of this project is the development of a cost efficient and reliable produc-tion technique to infiltrate carbon fibre yarns with aluminium in a cold chamber die casting machine. Of high importance is the influence of process parameters, like plunger velocity and temperature of die, melt and carbon fibre preform [6-10].

The biggest influence for a successful infiltration is the right temperature control of mould and fibres. If the fibres are arranged very close to the mould cavity or have even contactwithit,mouldtemperaturesupto250°C,whicharecommonforpressuredieca-sting, are not enough to get a complete macroscopic infiltration of the fibres. The reason for this is the strong cooling down of the fibres which are in contact with the relatively cold mould. Just because of this there is premature freezing and the melt solidifies at the surface without infiltrating the structure. To reduce this effect we have integrated electrical cartridgeheatersintothemouldwhichincreasethemouldtemperatureupto400°Candimprove therefore the macroscopic infiltration quality. But the high mould temperature causes strong adhesions of the aluminium melt at the mould which lead to a reduced

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lifetime.Forthisreasonmouldtemperaturesof350°Cshouldnotbeexceeded.Butwiththis temperature a complete infiltration cannot be reached. Hence additionally the tempe-rature of the fibres has to be considered.

A temperature of the fibres near the melting point of the used metal alloy should be high enough to avoid premature freezing of the melt and therefore allows a complete infiltration. But cooling down of the fibres after the preheating process cannot be preven-ted and so a overheating of the fibres is necessary. Our results show that an increase of thepreheatingtemperatureupto900°Ceffectsabigimprovementofmacroscopicinfil-tration quality.

Making use of these adapted parameters the examination of the microstructure shows an almost complete infiltration of the fibres. The porosity of the specimen is less than 5 percent.

In summary our results demonstrate the large potential of pressure die casting as a low cost manufacturing process for carbon long fibre reinforced aluminium matrix composites. Essential is an accurate control of the melt, the mould and the perform tem-perature in combination with the mould filling and the infiltration velocity. This is the only way to avoid premature freezing and a deformation of the preform.

References

H.P. Degischer, P. Schulz, W. Lacom, in Key Engineering Materials, 1997, Vol. 127-131, pp. 99-110.1. O. Öttinger, R.F: Singer, in Zeitschrift für Metallkunde, 1993, Vol. 84 (12), pp. 827-831.2. L.J. Mazur, A. Mortensen, J.A. Cornie, M.C. Flemings, Metallurgical Transactions A, 1989, Vol. 20A, pp. 3. 2549-2557.C. Hausmann, O. Beffort, S. Long, in Verbundwerkstoffe und Werkstoffverbunde, 1999, pp. 153-158.4. A. Vassel, in Materials Science and Engineering A, 1999, Vol. 263, pp. 305-313.5. S.C. Kurnaz, M. Durman, in Zeitschrift für Metallkunde, 2002, Vol. 93(12), pp. 1252-1258.6. S. Long, O. Beffort, g. Moret, P. Thevoz, in Aluminium, 2000, Vol. 76(1/2), pp. 82-89.7. H. Kaufmann, R. Auer-Knobl, H.P. Degischer, in Zeitschrift für Metallkunde, 1994, Vol. 85(4), pp. 241-248. 8. C.g. Kang, K.S. Yun, in ICCM 9, 1993, S. 739-746.N.W. Rasmussen, P.N. Hansen, S.F. Hansen, in Materials Science and Engineering A, 1991, Vol. 135, pp. 9. 41-43.H. Eibisch, M. Hartmann, R.F. Singer, in 3. Ranshofener Leichtmetalltage, 2004, pp. 142-151.10. H. Eibisch, R.F. Singer, in Verbundwerkstoffe und Werkstoffverbunde, 2005, pp. 3-8.11.

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S-1.3

R. Kozera1, A. Dolata-Grosz2, M. Dyzia3, J. Bieliński4, A. Broda5, A. Boczkowska6, M. Gude7,

J. Śleziona8, K.J.Kurzydłowski9

1,5,6,9 Warsaw University of Technology, Faculty of Materials Science and Engineering, Woloska 141, 02-507 Warszawa 2,3,8 Silesian University of Technology Faculty of Materials Science and Metallurgy, Krasińskiego 8 40-019 Katowice4, Warsaw University of Technology, Faculty of Chemistry, Noakowskiego 3, 00-664 Warszawa7 Technische Universität Dresden, Institut für Leichtbau und Kunststofftechnik, 01062 Dresden

Investigations of the interfaces between carbon fibres and aluminium alloy matrix in the composites fabricated by pressure infiltration process

Aluminiummatrixcompositesreinforcedwithcarbonfibresareperspectiveengineeringmaterialsforlight-weightstructuralapplications.Particularadvantageofmetal–carbonfibercom-positesover theoneswithpolymermatrix ishigher transversestrengthandstiffnessandhigherthermalstability.Ontheotherhand,achallengeinproductionofsuchcompositesaretheinterfacereactionsbetweenfiberandmatrix.Theseinteractionsareespeciallyintensiveifdirectcontactofthefibreswithamoltenmetaltakesplace,asitmayresultinfiberdegradationand/orformationofundesirablebrittleintermetalliccompoundsneartothefibermatrixinterface.Detrimentaleffectsofthecontactwithmoltenmetalcanbereducedbycoatingthefibreswithprotectivelayersand/orbymodifiingthematrixalloyswithadditives,whichchangethesolubilityofthefiberatomsinametalmatrix.Bothmethodsmayalsoimprovewettabilityofthefibreswithaluminummatrixandreducepropoensityofformationofaluminiumcarbide,whichisbrittle,reactswithwaterandmaydramaticallydegradethemechanicalpropertiesofcomposites. Inthisworknickelcoatingswereappliedontothecarbonfibresbyelectro-lessdeposition.Alsoaspecialaluminiumalloywasusedwithexhibitingimprovedwettingofthecoatedfibres.Aseriesofcompositeswasfabricatedusing2Dwovenfabrics(TenaxHTA40)coatedwithNi(P)–seeFig.1aandb.Priortocoating,thefibreswereannealedat400°Cinairtoremovefromepoxysizingandsubsequentlyactivated/sensitizedwithSnCl2/PdCl2solution.TheNi(P)coatingprocesswascarriedoutwithaglycinebufferedbath(pH=8,5)for15minutes.Phosphorouscontentinthecoatingswas4.5wt%.ThemorphologyandstructureofNi(P)coatingswascontrolledbyobserva-tionswithScanningElectronMicroscopy,SEM. Thematrixchemicalcompositionwasoptimizedtoobtaingoodbondingwithcoatedfi-bres[1].ThereductionofthereactivityintheAl-Csystemwaspossiblebytheadditionof7wt%Si.SuchadditivesasMg,LiorNawerealsousedtoensureareductionofsurfacetensionandgoodwetting.

TheinfiltrationprocesswascarriedoutusingtheDegussapress(T=7200C,p=15MPa),[2].ThestructureofthecompositeswasstudiedusingLight,ScanningElectron(Fig.2)andTrans-missionElectronMicroscopictechniques.

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Figure1

2DwovenfabriccoatedwithNi(P)coating,(a)Compositeobtainedbyinfiltrationprocess.(b)

Figure2Surfaceofatfractureof thealuminaalloymatrixcompositereinforcedwith2DNi(P)coatedwovenfabrics

AcknowledgmentsThestudiesweresupportedbyPolishMinistryofScienceandHigherEducationandbyDFGinGermanyasthePolish-GermanBilateralProject“3D-textilereinforcedAl-matrixcomposites(3D-CF/Al-MMC)forcomplexstressedcomponentsinautomobileapplicationsandmechanicalengineering”.

Keywords:electro-lessplating,Ni(P)coatings,carbonfibres,aluminaalloys,composites,pres-sureinfiltration

References:A.Dolata-Grosz,M.Dyzia,J.Śleziona:Influenceofmodificationonstructure,fluidityand1.strengthof226Daluminiumalloy,ArchivesofFoundryEngineering,Vol.8,SpecialIssue3/2008,p.13-16.M.DyziaA.Dolata-Grosz,J.ŚlezionaW.Hufenbach,M.Gude,A.Czulak:Infiltrationtest2.ofcarbonfibrestextilebymodifiedAlSi9Cu(Fe),(Composites)9:3(2009),p.210-213.

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S-1.4

FaCTORS aFFECTInG WETTaBIlITY and InFIlTRaTIOn OF 3d-CF REInFORCEMEnT WITH lIQUId al-BaSEd MaTRIX

N. Sobczak1, A. Kudyba1, A. Siewiorek1, J. Sleziona2, A. Dolata-grosz2, M. Dyzia2, J. Bielinski3, R. Kozera4, A. Boczkowska4, K.J. Kurzydlowski4, H. Ballmes5,

C.A. Rottmair5, R.F. Singer5, M. gude6, A. Czulak6, F.Engelmann6, W. Hufenbach6

1Foundry Research Institute, 73 Zakopianska Str., 30-418 Krakow, Poland2Silesian University of Technology, Faculty of Materials Science and Metallurgy,

8 Krasinskiego Str., 40-019 Katowice, Poland3Warsaw University of Technology, Faculty of Chemistry, 3 Noakowskiego Str.,

00-664 Warsaw, Poland 4Warsaw University of Technology, Faculty of Materials Science and Engineering,

141 Woloska Str., 02-507 Warsaw, Poland5Institute of Metals Science and Technology, University of Erlangen-Nuernberg,

Martensstr. 5, 91058 Erlangen, germany6Institute of Lightweight Engineering and Polymer Technology (ILK), Technische

Universität Dresden, germany

Keywords: 3D-CF/Al-MMC, high-temperature phenomena, in situ observation

The paper summarizes the research on understanding the factors affecting high-temperature liquid-assisted interfacial phenomena, which take place at different stages of cast ceramic-metal composite fabrication and influence the quality of the final products. The work has been done by collaborating teams in Polish-german research project devoted to the development of Al-matrix composites reinforced with continuous carbon fibres (CF) by infiltration of textile type 3D-CF preforms with liquid Al-matrix alloys. It is widely recognized that at industrially important low temperatures (<800ºC), liquid Al and most Al-alloys do not wet carbon materials, independently on their type (graphite, vitreous carbon, diamond, carbon fibers). At high temperature, wetting in the Al/C system is accompanied by intensive formation of undesirable carbide Al4C3, responsible for low corrosion resistance and brittleness of the composite material. The real-time observations of the wetting behaviour and solidification of model (liquid Al-matrix/dense substrate using graphite, vitreous carbon, Ni) and real (liquid Al/CF using 2D- and 3D-carbon fibres preforms) systems have been performed under high vacuum using different testing procedures (classical sessile drop, improved dispensed drop, “up-“ or “down-” infiltration, pre-preg infiltration). The results have evidenced the following key factors affecting the wetting, infiltration, physicochemical compatibility between Al-matrix and CF reinforcement and the formation of the casting defects (porosity, cracks, non-uniform reinforcement distribution) responsible for weakening of 3D-CF/Al composites (Figure 1):

coatingcarbonmaterialswithNi-Playerof≤4%Passuresthestrongestwettability1. improvement(contactangleθ<<90º);furtherincreaseinPcontentresultsinnon-wet-tinganddebondingofthecoatingandthusinthelostofitsfunctionality;

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Fig. 1. Light microscopy images of 3D-CF/Al-MMC produced by pressure-less infiltration of Ni-P-coated CF performs illustrating the presence of large crystals of brittle Al3Ni formed due to dissolution of Ni-P coating in liquid Al-matrix (a-c), residual sizing inclusions (a,c), gas and

shrinkage porosity (b-d), oxide films (b,c), non-wetting due to discontinuities in Ni-P coating (d), non-uniform CF distribution (d).

Acknowledgements: The study has been financed by the Ministry of Science and Higher Educa-tion of Poland and DFG in Germany in frame of the Polish-German Bilateral Project “3D-textile reinforced Al-matrix composites (3D-CF/Al-MMC) for complex stressed components in automobile applications and mechanical engineering”.

for Ni-P-coated CF, temperature and time of liquid metal/CF contact as well as the 2. P content should be optimized for each selected Al-matrix in order to suppress undesirable growth of brittle intermetallic phases, both as continuous layers at the interfacesorseparateprecipitatesinAl-alloymatrix;alloying Al-matrix with carbide-forming elements improves wetting, bonding and, 3. under certain processing conditions, it may improve physicochemical compatibility by the formation of beneficial carbide instead of Al4C3;primary oxide film on Al-matrix prevents the formation of a true Al/C contact resulting 4. in local non-wettinganddebonding; therefore, the liquidmetal shouldbeproperlyprepared before its contact with CF reinforcement while the metal oxidation should be limited, especially at the first stages of the composite processing by infiltration methods;special attention should be paid to the pretreatment of 3D-CF preforms since during 5. heating, gasification from industrially available CF due to presence of epoxy sizing strongly influences infiltration kinetics and the released gases are responsible for secondaryliquidmetaloxidationandtheformationofstructuraldiscontinuities;liquid alloy shrinkage during solidification results in the formation of porosity, cracking, 6. CF displacement and thus non-uniform distribution of reinforcement.

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S-1.5

MoDellinG of fiBRes BReAKinG in coMposites usinG fRActAls chARActeRistics

M. Rybaczuk, D. Aniszewska

Wroclaw University of Technology Institute of Materials Science and Applied Mechanics25 Smoluchowskiego Str., 50-370 Wroclaw, Poland

Keywords: modelling,fibresbreaking,fractals

Making use of the proposed numerical methods of modelling we can observe damage growth for static, dynamic and fatigue loads without using invasive experimental methods.Well-knownnumericalmethods are based on finite-elementmethod, but ourresearch is based on cellular automata, which is an alternative method to study behaviour ofdynamicalsystems.Thenumberoffiniteelementsnecessarytostudychangesinstressfieldsresultingfromsinglefiberbreakexceedsabilitiesofexistingcomputers.Weassumedefects evolution in composite as a dynamical system depending on external and internal forcesandpropertiesoffibres.Ourworkisamoreadvancedresearchthanfractalgrowthexaminationincross-sectionofcompositeduringstochasticsimulationsoffibresbreakingpresented in [1]. Modelling composite with cellular automata makes possible observation of mate-rial processes precede defects appearance an their propagation over full range of length scales: micro-, meso- and macroscopic. The fatigue experiments are performed for speci-mens with different kind of material defects, even a notch. The existing notches or other inhomogeneities make differences in material behaviour and defects growth. Precise nu-mericalmodelofcompositeallowuscontrolmaterialstructure,propertiesoffibresandmatrix, external conditions and fatigue experiment requirements. Theproposedmodeloffibresbreakingisessentiallythestochasticonereflectingrandomnatureofdefectsevolution.Theindividualfibrebeakdisturbsstressfieldinthevincinityofbreakpoint.Thismodifiesprobabilityofbreakoffibressufficientlysufficientlyclosetobreakpoint.Simplyforcesactingontoneighbooringfibresincrease.Theprobabil-ityoffibrebreakisgivenbyWeibulldistribution.AccordingtonumerofbrokennearfibresandspatialdistributionthisWeibullprobabilitybecomesmodified.Inmetalmatricompositefibres interact throughmatrix.ThereforemodificationofWeibulldistributiondependsonmatrix characteristics. Our goal is investigation of defects evolution and formulating them in terms of fractals. Fractal geometry is able to describe the complexity of defects in composite, as in any other material, using fractal dimension and their size with fractal measure. It is ap-plied to examine irregular or fragmented shapes in nature from very beginning. Structure of composite model provided by cellular automata is discrete, point defects in composite are included into mesoscopic range and make continual approximation possible, therefore

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fractal geometry can be applied. Fractal characteristics are used to measure and verify that certain irregularity is a crack. SimulationsofbreakingfibresincompositemodelcreatedwithcellularautomataconcernrectangularandNOLspecimenswithparallelfibreswithvarioussettingsofmini-malandmaximalforceforsinglefibre,variousvaluesofparametersofWeibulldistribu-tion, time and correlation radius. Different settings generate different behaviour of com-posite As an example a few different behaviour are presented.

Acknowledgments: The work has been prepared as part of the Polish-German grant „3D textile reinforced aluminium-matrix composites for complex loading situations in automobile and machine parts”.Calculations have been carried out in Wroclaw Centre for Networking and Supercomputing (http://www.wcss.wroc.pl).

References

M. Rybaczuk, P. Stoppel: The fractal growth of fatigue defects in materials, International Journal of 1. Fracture 103: 71–94, 2000.

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67


postersession

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69


Poster SessionPS-1.1

Porous ceramic preforms for production of metal-ceramic composites by infiltration methodA. Ozieblo, Z. Jaegermann

PS-1.2Changes of properties of aluminium matrix composite reinforced with SiC particles after multiple remeltingA. Klasik, A. Wojciechowski, N. Sobczak, J.J. Sobczak

PS-1.3al3Ti particles reinforced aluminium matrix composites for plastic working W. Szymanski, M. Lech-grega

PS-1.4Microstructure differences of composites reinforced with SiC particles K. Pietrzak, D. Rudnik, A. Wojciechowski, J.J. Sobczak, P. Darlak

PS-1.5Interaction between liquid titanium and ZrO2-based ceramics A. Karwinski, N. Sobczak, R. Nowak, A. Kudyba, M. Homa, W. Lesniewski,

E. Sienicki

PS-1.6austempered ductile iron – new grade of the first man-made compositeD. Myszka

PS-1.7Wettability and reactivity in al/MgO and al/Mgal2O4 systemsR. Nowak, N. Sobczak, E. Sienicki

PS -1.8Interaction between molten Inconel 740 alloy and oxide ceramicsR.M. Purgert, N. Sobczak, R. Nowak, M. Homa, E. Sienicki

PS - 1.9Experimental complex for investigations of high-temperature capillarity phenomenaN. Sobczak, R. Nowak, W. Radziwill, J. Budzioch, A. glenz

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PS - 1.10Interaction between molten aluminium and cobalt oxide single crystalN. Sobczak, W. Radziwill, R. Nowak, A. Kudyba, J. Morgiel, J. Wojewoda-Budka

PS - 1.11Effect of carbon coating on wetting and bonding of al alloys with al2O3 substrates R. Nowak, N. Sobczak, W. Radziwill, A. Kudyba, A. Wojciechowski, D. Rudnik

PS - 1.12Wetting and reactivity between molten aluminium and zinc oxideN. Sobczak, W. Radziwill, A. Kudyba, R. Nowak, J. Oblakowski

PS - 1.13Theoretical aspects of ordered porosity metallic materials produced by unidirectional solidification of gas saturated meltL. Drenchev, J.J. Sobczak

PS - 1.14Investigation of composition and thermodynamic characteristics of al-based casting composite materials N.I. Llinykh, V.E. Sidorov

PS - 1.15The influence of heat treatment of metallic melts (HTM) on structure and properties of solidified hypo-autectic silumines P. Popel, E. Rozhicina, I. Brodova, O. Chikova

PS - 1.16Graphite to 304SS braze joining by active metal brazing technique - Improvement of mechanical propertyA.K. Ray, A. Kar. S.A. Kori, L.C. Pathak, A. Sonnad

PS - 1.17Interface analysis of YSZ - to - metal brazes fabricated with reactive filler metalsJ.E. Indacochea, O.A. Quintana

PS - 1.18Surface treatment of the aluminium matrix composite materials with concentrated electric discharge in magnetic fieldT.A. Chernyshova, R.S. Mikheev, A.M. Rybachuk

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POROUS CERaMIC PREFORMS FOR PROdUCTIOn OF METal-CERaMIC COMPOSITES BY InFIlTRaTIOn METHOd

A. Ozieblo, Z. Jaegermann

Institute of glass, Ceramics, Refractory and Construction Materials, Warsaw, Poland

Keywords: processing ceramic, preforms, characterization

Squeeze casting - the type of pressure infiltration - is one of the production me-thod of metal-ceramics composites. This process is based on filling ceramic performs (porous ceramic with cellular structure) by liquid metal using external pressure. The main advantage of this method is the possibility of forming percolation microstructure compo-sites with defined distribution of ceramic phase. This is possible due to stiff, high open porous ceramic preform which allows its infiltration by liquid metal. The method avo-ids disadvantages of sedimentation or flotation, typical for production of metal–ceramics composites in other ways. The main requirements for the preforms are the following: total open porosity 60–90%, good wettability by liquid metal, mechanical strength sufficient to ensure preform rigidity during infiltration and minimal chemical reactivity.

Selected technological aspects of forming alumina preforms of homogeneous porosity by polymeric sponge method will be discussed in the article. The technique con-sists in depositing ceramic slip on polyurethane sponge and then sintering the ceramic body. During firing the sponge burns and ceramic structure correspond reproducing the structure of the sponge – sinters. Polymeric sponge forming method is the best for manu-facturing high open porosity materials with large pore size.

For the preform production alumina material based on Al2O3 powder doped by magnesium and calcium oxides was used. Cylinder-shaped preforms measuring 70 mm in diameter and about 16 mm in height, characterized by total porosity about 80–90% and pore size about 0.2–0.7 mm were formed. One of the preforms and its porous structure were shown on Figure 1.

Mechanical compressive strength of preforms was also evaluated. Performed tests showed that compressive strength of porous alumina material depended mainly on total porosity but almost not on the density of sponge matrix and varied between below 1 and 10 MPa.

Preforms were used for manufacturing composite castings by pressure infiltration of alumina scaffolds by liquid aluminium alloys.

PS-1.1

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Fig. 1. Exemplary alumina preform (a) and (b) stereomicroscopic image of its porous structure

Fig. 2. Compressive strength vs. total porosity of alumina preforms based on sponge matrices of 30, 45 and 60 pore per inch density

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CHanGES OF PROPERTIES OF alUMInUM MaTRIX COMPOSITE REInFORCEd WITH SiC PaRTIClES aFTER MUlTIPlE REMElTInG

A. Klasik1, A. Wojciechowski1, N. Sobczak1,2, J.J. Sobczak2


Keywords: aluminium matrix composite, remelting, recycling

1. Introduction The development of production techniques results in increase of ready products,

which after the end of the technical exploitation demand their recycling or storage. One of more ardous groups of products determines car vehicles with drawn from exploitation. Toge-ther with the increase of the quantity of used up cars, the interest in recycling problems occurs because more than one this process determines not only the guarantee of the environment protection, but simultaneously the possibility of gaining over of valuable secondary raw ma-terials. Introduced again to the technological circulation they can be the source of materials about similar functional properties as the original material. From the materials engineering point of view, Al-matrix composites are the group of advanced materials, which can be applied in the automotive industry because of their light-weight, low-cost and very attractive functional properties [1–3]. However, the problem of the recycling is still open and should be solved in order to introduce metal matrix composites (MMCs) to wide-scale production. The simple, univocal selection of used composites element for brake assembly allows producers to recycle material and use it for secondary parts production through multi-remelting.

Following the EU environmental regulations (e.g. Directive 2000/53/EC of the Euro-pean Parliament and of the Council of 18 September 2000 on end-of-life vehicles), there is a need on information regarding the behavior of materials during different recycling treatments before introduction new products in industry.

2. Experimental procedure The analysis of conditions for MMCs remelting and of the effect of remelting number

on selected physical, mechanical and utility properties has been done on example of F3S.10S composite (A359 aluminum alloy reinforced with 10 vol.% SiC particulates). After each remel-ting operation, structural characterization coupled with X-ray examination as well as the me-asurements of electrical conductivity, density, hardness (HBW), ultimate strength (Rm), Young modulus (E), elongation (A), yield limit (R0.2), elastic limit (R0.05), wear resistance (defined as mass decrement) were carried out and compared with those investigations of as-received composite material.

3. Results and discussion The results of investigation of physical and mechanical properties show that recycling

treatment, characterized by the number of remelting followed by the same casting procedure, causes the noticeable change of all properties of composite material. Examples are shown in the Figures 1, 2.

PS-1.2

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90

110

130

150

170

190

210

230

250

1 2 3 4 5 6 7 8 9 10

Remelts

Stre

ss, M

Pa

R0.2

Rm

R0.05

y=-2E-05x+0,0047R2 = 0,0742

y = -7E-06x - 0,0039R2 = 0,0022-0,006

-0,004

-0,002

0

0,002

0,004

0,006

1 2 3 4 5 6 7 8 9

Remelt number

Wea

r res

ista

nce

[g]

Material of sample

Material of antisample

Fig. 2. Wear resistance of F3S.10S after successive remelting

Fig. 1. Tensile strength properties of F3S.10S composite after successive remelting

For multiple remelting (up to 10th remelting), structural observations by optical and scanning electron microscopy do not demonstrate any remarkable changes, compared to as-received composite (Figs. 3, 4).

Fig. 4. Microstructure of F3S.10S composite after 1st remelting, magnification 500x

Fig. 3. Microstructure of F3S.10S composite after 1st remelting, magnification 500x

Moreover, there is no essential degradation of SiC particles while the qualitative inva-riability of the reinforcing phase morphology is ascertained within the range of its content and distribution, independently on the remelting number. In the same time, a continuous decrease in utility properties of composite material with increase of the number of remelting operations was recorded, showing their tolerable reduction after 9th remelting. The results obtained are analyzed from point of view of possible improvements of recycling process by proper selection of liquid metal treatment and subsequent casting procedure.

Acknowledgments: This work was sponsored by the Ministry of Science and Higher Education of Poland under the project No. PBZ-KBN-114/T08/2004.

ReferencesD.Rudnik,J.Sobczak:Tłokikompozytowedosilnikówspalinowych,InstytutTransportuSamochodowego,1. Warszawa, 2001, ISBN 83-913045-7-4.J. Sobczak: Kompozyty metalowe, Instytut Odlewnictwa, Instytut Transportu Samochodowego, Kraków-2. Warszawa, 2001. ISBN 83-913045-8-2.A. Wojciechowski, J. Sobczak: Kompozytowe tarcze hamulcowe pojazdów drogowych, Instytut Transportu 3. Samochodowego, Warszawa, 2001, ISBN 83-913045-6-6.

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al3Ti PaRTIClES REInFORCEd alUMInIUM MaTRIX COMPOSITES FOR PlaSTIC WORKInG

W. Szymanski, M. Lech-grega

Institute of Non-Ferrous Metals in gliwice, Light Metals Division at Skawina

Keywords: Al-Al3Ti, processing, characterization

In all sectors of the industry, the materials used currently are expected to meet the always more stringent requirements. This is why materials engineers are searching for new combinations of metals, alloys and intermetallic compounds, mainly through new technologies of their fabrication, to mention as an example the composite materials assi-gned for plastic working.

For some time now, studies of the composites based on aluminium and alumi-nium alloys have been successfully carried out by the Institute of Non-Ferrous Metals in gliwice and its Light Metals Division at Skawina (IMN-OML Skawina).

The aim of the studies was, among others, to improve the structure and proper-ties of the aluminium alloy-based composites reinforced with particles of an intermetallic Al3Ti phase, assigned for further plastic working, i.e. for extrusion and forging. As descri-bed in this paper, the studies included the extrusion process carried out under laboratory conditions on a press of 600 kN extrusion force. Due to the application of extrusion it has been possible to produce a material characterised by the mechanical properties definitely superior to those obtained by a casting process (Fig. 1). The said properties are incre-asing with an increasing content of the reinforcing phase, i.e. Al3Ti (Fig. 2).

The properties of the extruded composites were comparable to the properties of the extruded 7475 alloy processed to T6 condition. The hydrostatic state of stress created by the extrusion process resulted in good consolidation of the composite constituents, while the following heat treatment improved further the properties of the fabricated mate-rial.

Fig. 1. Hardness values obtained in a 7475 alloy-based composite reinforced with Al3Ti particles: as-cast () and as-extruded ()

condition

Fig. 2. The values of Rp0.2 obtained during com-pression test in an extruded 7475 alloy-based

composite reinforced with Al3Ti particles

PS-1.3

Volume fraction of Al3Ti [5%] Volume fraction of Al3Ti [5%]

76


Within the “Innovative Economy” Operational Programme, Priority 2, Axis 2.2, the „MałopolskieCentreofInnovativeTechnologiesandMaterials”,whichisaConsortiumoffour research entities, has been granted a financial support for the Investment Project entitled:“RetrofittingaResearchInfrastructureof theMałopolskieCentreof InnovativeTechnologies and Materials”. Under this project, the IMN-OML Skawina will purchase some equipment to enable further tests to be carried out on semi-industrial scale. The following equipment will be purchased:

a CONFORM type device for continuous extrusion where the feedstock can be either -in the form of solid material (bars, wire) or in the form of rapidly cooling loose mate-rials(powders,chips)(Fig.3.);a horizontal hydraulic, direct-indirect, extrusion press of a 500 T locking force, provi- -ded with a handling equipment, a puller and a receiver for the extruded stock with a drive system, as well as an induction heater for zone heating of the billets, and a 20 T locking force stretching machine for bars 2 to 7 metres long (Fig. 4.). The above mentioned devices are expected to offer wide research opportunities

and enable further studies to be conducted on the techniques of composite forming to improve the consolidation behaviour and properties of thus produced materials.

Fig. 3. A CONFORM type device for continuous extrusion

Fig. 4. A horizontal hydraulic press of 500T locking force

This year, at IMN-OML Skawina, a vertical hydraulic press of 250 T maximum locking force has been put in operation (Fig. 5.). The press is a part of the new stand to test the plastic working of aluminium and magnesium alloys.

Fig. 5. A PHC 250 press (test stand operating at IMN-OML Skawina)

77


Fig. 1. Microstructure of AK12 alloy, phase contrast, magn. 100x: a) argon,

b) nitrogen

Fig. 2. Microstructure of F3S20S compo-site, reinforced with SiC particles (20% content) phase contrast, magn. 100x:

a) argon, b) nitrogen

a b

c d

MICROSTRUCTURE dIFFEREnCES OF COMPOSITES REInFORCEd WITH SiC PaRTIClES

K. Pietrzak1, D. Rudnik1, A. Wojciechowski1, J.J. Sobczak2, P. Darlak2

1 Motor Transport Institute, 80 Jagiellonska Str., 03-301 Warsaw, Poland2 Foundry Research Institute, 73 Zakopianska Str., 30-418 Krakow, Poland

Keywords: Al-SiC, particulate, reinforcement, microstructure

1. Introduction Metal matrix composites are a class of material that have been the subject of significant research

and development effort over the past 30 years. MMCs offer many advantages over conventional metallic alloys including: high tensile strength and stiffness under lightweight design, enhanced fatigue resistance, increased elevated temperature strength, improved wear resistance, control over thermo-physical properties (thermal expansion and conductivity) through variations in reinforcement type and volume fraction [1, 2, 3, 4].

These advantages make MMCs an attractive class of engineering materials for industrial applica-tions such as motorization, military and aerospace. They are involved also in the electronics, sporting goods (especially as nanocomposites). The use of composite materials is obligatory if a special properties can only be achieved by application of these materials. The application of these material in technical design requires investigations of material characteristics including the influence of technological parameters on microstructure. This research is concentrated on aluminium alloys reinforced with silicon carbide particles.

2. Experimental procedure The qualitative microstructure observations of AK 12 alloy (as reference material) and F3S20S com-

posite were carried out in not etched state by means of an optical microscope. The aim of these observations was to answer on the question whether exists or not the influence of used atmosphere on the microstructure of the alloy and composite. The same observations were performed in the case of composite material produced by squeeze casting and heat treated. The aim of these observation was to ascertain the microstructure stability or not of tested samples. The next problem was to assess the influence of centrifugal casting on differences of composite microstructure.

3. Results and discussionThe microstructures of AK12 alloy cast in argon and nitrogen atmosphere are shown in

Figure 1. Microstructures of F3S20S composite (argon and nitrogen atmosphere too) are shown in Figure 2.

PS-1.4

In both kinds of materials, within the range of the light-microscopy, were not observed any structural significant differences independently on used atmosphere.

78


The microstructures of composites produced by squeeze casting and heat treated are visualized in

Figure 3. Qualitative investigations in the optical microscopy range confirm the microstructure stability of tested samples. In the case of centrifugal casting the material discontinuities were observed as well as the significant decrease of SiC particles content near the sample surface (Fig. 4).

Fig. 3. Microstructures of composite material, reinforced with SiC particles (20% con-tent), produced by squeeze casting and heat treated (T71), phase contrast, magn.

500x, samples: a) 51,

b) 52, c) 53, d) 54

a b

d

c

a b c

Fig. 4. Microstructures of F3D 30S composite material, reinforced with SiC particles (30% content), centrifugal casting, phase contrast, magn. 100x, samples: a) C1-1- near the surface,

b) C1-2 - a half of distance from the rotation axis, c) C1-3 - near the rotation axis

3. ConclusionsThe results allow to formulate the following conclusions:

the change of the argon/nitrogen atmosphere does not cause the significant changes of the AK12 alloy •microstructureandF3S20Scompositemicrostructurequalitativeassessed;metal matrix composites produced by means of squeeze casting show the microstructural stability in the •range of geometrical parameters of introduced SiC particles as well as in the range of geometrical para-metersofcompositematrixcompounds;metal matrix composites produced by centrifugal casting show that microstructure, closed to sample sur-•face, is SiC semi-free but in the a half of distance from the rotation axis and near it microstructural stability is observed in the range of introduced SiC particles as well as in the range of composite matrix compo-unds;metal matrix composites produced by centrifugal casting show the occurrence of material discontinuities.•

Acknowledgments: This work was sponsored by the Ministry of Science and Higher Education of Poland under the project No. PBZ-KBN-114/T08/2004.

ReferencesJ. Sobczak : Kompozyty metalowe, Instytut Odlewnictwa-Instytut Transportu Samochodowego, Kraków-1. Warszawa 2001, ISBN 83-913045-8-2.K.U.Kainer: Metal matrix composites. Custom-made materials for Automotive and Aerospace Engineering, 2. ISBN 3-527-31360-5, Copyright 2006 WILEY-VCH Verlag gmbH & Co. KgaA, Weinheim.Achievements in Materials and Manufacturing Engineering, Volume 24, ISUUES 2, October 2007, 3. pp. 183-186.A. Wojciechowski, J. Sobczak: Kompozytowe tarcze hamulcowe do pojazdów drogowych, Instytut Trans-4. portu Samochodowego, Warszawa, 2001, ISBN 83-913045-6-6.

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PS-1.5

InTERaCTIOn BETWEEn lIQUId TITanIUM and ZrO2-BaSEd CERaMICS

A. Karwinski1, N. Sobczak1,2, R. Nowak1, A. Kudyba1, M. Homa1, W. Lesniewski1, E. Sienicki2

1Foundry Research Institute, 73, Zakopianska Str., 30-418 Krakow, Poland 2 Motor Transport Institute, 80 Jagiellonska Str., 03-301 Warsaw, Poland

Keywords: titanium, ZrO2, Y2O3, CeO, wetting, reactivity, interfaces, bonding

The aim of this work was to study the wetting behavior and interfaces between liquid titanium and selected oxide substrates in order to identify their applicability for the production of Ti castings locally reinforced with porous or dense ceramic preforms. The oxide substrates were made from a powder of ZrO2 stabilized by CaO using different binders containing colloidal nanoparticles of CeO, ZrO2 and Y2O3. For compari-son, the tests were done also with oxide substrates produced by conventional technique using binders (Titanbinder or Ecosil). Thewettabilitytestshavebeendonebyasessiledropat1800°Cinflowingargonusing contact heating of a couple of materials to testing temperature.Melting, wetting, spreading and solidification behaviors have been recorded using high-speed CCD camera. The images of the drop/substrate couples were used for the image analysis in order to measure the contact angles formed by the liquid alloy on the selected substrates as well as to estimate the alloy expansion and shrinkage during heating and cooling, respectively. The structures of the surfaces and interfaces in solidified sessile drop samples were examined by optical and scanning electron microscopy (SEM) coupled with EDS analysis.

Table 1. Contact angles and bonding of liquid Ti (99.5%) with selected Zr2O3-based substrates (1800°C, Ar)

PropertyColloidal nanoparticle additions Binders

ZrO2 Y2O3 CeO Titanbinder EcosilContact angle,

θ[°]151 156 124 145 124

Bonding no yes no no noReactivity slight no no yes yes

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The selected results of the wettability tests and structural examinations are sum-marized in Table 1. Liquid titanium does not wet the novel ZrO2-based ceramics produced using additions of CeO, ZrO2 and Y2O3 nanoparticles. The SEM+EDS characterization does not distinguish any new phases at thesurface and inside the Ti droplets after interaction with novel ceramics. Contrary to the substrates produced using conventional binders, the examination of the substrate-side interfaces does not show any continuous layers of reaction products.Only in the case of ZrO2 substrates produced with ZrO2-nanoparticles, the presence of separate precipitates was noted at the substrate-side interface. For all tests except those with the substrates produced using Y2O3-nanoparticles, visual observation of the behavior of Ti droplet during high-temperature wettability tests and subsequent cooling evidenced the droplet debonding. Most probably, it takes place due to metal shrinkage and mismatch in the coefficients of thermal expansion for Ti and ceramic. Thus, after the tests, the Ti droplet was always separated from the substrate. For the substrates produced using Y2O3-nanoparticles, the solidified sessile drop couples had a good drop/substrate bonding despite a high contact angle recorded (Table 1). The novel ceramic materials produced using different binders containing colloidal nanopartices demonstrate much better chemical stability in contact with liquid Ti, com-pared with conventional ceramics. Thus they might be recommended for the production of porous performs or dense inserts for local reinforcing of Ti parts using liquid-assisted processes.

Acknowledgements: This work has been sponsored by the Ministry of Science and Higher Educa-tion of Poland under the project No N507 048 31/1208.

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PS-1.6

aUSTEMPEREd dUCTIlE IROn – nEW GRadE OF THE FIRST Man-MadE COMPOSITE

D. Myszka

Warsaw University of TechnologyPlac Politechniki 1, 00-661 Warsaw, Poland

Keywords: in situ composites, ADI, processing

Though invented nearly 2500 years ago, cast iron as a first man-made composite still remains the most important casting material. It is cheap, the process of its manufac-ture has been well mastered by now, while numerous grades of this material offer a wide range of properties, to mention just some of the benefits. Its never-ending popularity the cast iron also owes to wide-scale investigations, an outcome of which has been the in-vention of new grades of this material, e.g. the ductile iron and ADI (Austempered Ductile Iron).

The studies published since early 70ties of the past century clearly indicate that ADI has been created to play the role of a highly responsible engineering material, which – owing to its undeniable advantages – is expected to replace many other well-known materials. This article offers a review of the numerous research works which have been recently done on ADI in Poland and in the world.

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PS-1.7

WETTaBIlITY and REaCTIVITY In al/MgO and al/Mgal2O4 SYSTEMS

R. Nowak1, N. Sobczak1,2, W. Radziwill1, E. Sienicki2


Keywords: wettability, reactivity, Al/MgO, Al/MgAl2O4

The effects of testing procedure, temperature and single crystal oxide orientation on wetting behavior of liquid aluminum on MgO and MgAl2O4 were investigated in a vacuum atatemperatureof800-1000°Cfor2htimeofcontact.Thecontactanglemeasurementswere done with monocrystalline oxide substrates of (100), (110) and (111) crystallogra-phic orientation polished up to 1 nm roughness. A sessile drop method was applied using two procedures: 1) conventional contact heating (CH) of the Al/oxide couples to experi-mental temperature and 2) separate heating of a couple applied together with capillary purification (CP) of a drop by squeezing a metal through a graphite capillary.

Under test conditions, liquid Al does not wet both MgO and MgAl2O4, independently on substrate crystallographic orientation and testing temperature. These two factors af-fect both high temperature behavior of the Al/oxide couples and the value of final contact angles (Fig. 1).

Fig. 1. Wettability kinetics for a) Al/MgAl2O4 system; b) Al/MgO system (CH - contact heating, CP - capillary purification)

83


For both oxides, the formation of whiskers at the substrate surface is noted to oc-cur during wettability tests while the degree of substrate surface whiskering, characterized by the length and number of whiskers, depend on the oxide type, substrate orientation and temperature, showing the strongest effect on the (100) oriented substrates. Structu-ral characterization of sessile drop samples evidences the substrate surface roughening near the Al drop. The formation of reaction product region in the substrate under the Al drop was noted to occur (Fig. 2). It is composed of alumina precipitates surrounded with Al(Mg) continuous phase formed due to oxy-redox reaction between Al and oxide which was suggested to be a main reason of the substrate whiskering effect.

Fig. 2. a) SEM side-view of Al/MgAl2O4 (110) couple showing substrate surface whiskering effect due to contact heating at 900°C for 2 h;

b) SEM view of cross-sectioned Al/MgO(111) couple (CH, 1000°C, 1 h) showing the formation of reacting product region composed with 2 zones of different morphology and phase composition:

I – Al2O3 + Al(Mg); II – Mg(Al) + MgAl2O4

Acknowledgements: This work is sponsored by the Ministry of Science and Higher Education of Poland under the project No. PBZ-KBN-114/T08/2004.

a) b)

84


PS-1.8

InTERaCTIOn BETWEEn MOlTEn InCOnEl 740 allOY and OXIdE CERaMICS

R.M. Purgert1, N. Sobczak2,3, R. Nowak2, M. Homa2, E. Sienicki3

1Energy Industries of Ohio, Park Center Plaza, Suite 200, 6100 Oak Tree Boulevard, Independence, OH 44131, USA

2Foundry Research Institute, 73 Zakopianska Str., 30-418 Krakow, Poland3Motor Transport Institute, 80 Jagiellonska Str., 03-301 Warsaw, Poland

Keywords: Ni-MMC, wettability, reactivity, Inconel 740, oxides

The aim of this work was to study the wetting behavior and interfaces between liquid titanium and selected oxide substrates in order to identify their applicability for the production of Ni-superalloy castings locally reinforced with porous or dense ceramic per-forms as well as by dispersion of oxide particles in Ni-based matrix using liquid assisted methods. The sessile drop method has been applied for the investigation of wettability and reactivity between molten Ni-superalloy Inconell IN740 (Fe-2, C-0.07, Co-20, Cr-24, Nb-2, Mo-0.5, Ti-2, Al-1, Ni-bal, wt.%) and selected oxides. Two types of polycrystalline substrates of Al2O3, Y2O3, and ZrO2 produced by high-temperature synthesis were used: 1) dense substrates produced by conventional high-temperature synthesis: Al2O3, Y2O3, and ZrO2;2)poroussubstratesproducedusingadditionsofoxidenanoparticles:(Y2O3)

np and ZrO2)

np. Thewettabilitytestshavebeenmadeunderhighvacuumat1500°Cinflowinggas (Ar) under pressure of 850-900 mbar using contact heating up to experimental tem-perature together with continuous recording of temperature (by 3 thermocouples) and pressure level. Melting, wetting, spreading and solidification behaviors have been re-corded using high-speed CCD camera. The images of the drop/substrate couples were used for the image analysis in order to measure the contact angles formed by the liquid alloy on the selected substrates as well as to estimate the alloy expansion and shrinkage during heating and cooling, respectively. The solidified sessile drop couples were used for detailed characterization of structure and chemistry of surfaces and interfaces using optical and scanning electron microscopy coupled with energy dispersion surface (EDS) analysis.

Table 1. Wetting properties of selected oxide substrates by molten IN740 alloy

Substrate Contactangle,θ[º] Reactivity Bonding ZrO2+(Y2O3)

np 150 + -ZrO2+(ZrO2)

np 129 + -Al2O3 94 + +Y2O3 98 + +

ZrO2+3%Y2O3 95 + +

85


The results of wettability tests and structural characterizations are summarized in Tab. 1. Interaction of IN740 alloy with all selected substrates shows non-wetting cha-racter despite the fact that certain degree of reactivity was recorded and the formation of oxygen-rich precipitates at the drop surface as well as at the substrate-side interface was noted (e.g. Fig. 2). For dense ZrO2+3%Y2O3 substrates, the interaction with liquid IN740 alloy is accompanied by the nucleation of gas bubbles at the substrate surface (Fig. 2). Visual observations of the behavior of IN740 droplet during high-temperature tests show that among the examined substrates, those produced using nanoparticles do not bond with IN740. For other substrates, debonding takes place during droplet soli-dification and cooling due to mismatch in thermal expansion coefficients between IN740 and ceramic substrate. In most cases debonding occurs along the drop/substrate inter-face and only the IN740/Y2O3 couple evidences a mixed fracture (inside the substrate and at the interface).

a)

b)

drop-side interface

drop surface

Fig. 1. SEM images of drop-side (a) and substrate-side (b) interfaces of the IN740/ZrO2+3%Y2O3 couple (1500ºC)

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PS-1.9

EXPERIMEnTal COMPlEX FOR InVESTIGaTIOn OF HIGH TEMPERaTURE CaPIllaRITY PHEnOMEna

N. Sobczak1, R. Nowak1, W. Radziwill1, J. Budzioch2, A. glenz2

1Foundry Research Institute, 73 Zakopianska Str., 30-418 Krakow, Poland2PREVAC Ltd, 61 Raciborska Str., 44-362 Rogow, Poland

Keywords: high-temperature measurements, equipment design, testing methods

The paper presents the description of unique experimental complex that has been designedforinvestigationsofdifferentmaterials(metals,alloys,ceramics,glass,fluxes,dross)athightemperature(upto2100°C)andundervacuumorinprotectiveatmosphere(static or flowing gaswith controlled rate at required level of pressure). Particularly, itis useful for visualization of materials behavior in order to understand high-temperature phenomena and to estimate materials thermo-physical properties, e.g. surface tension, densityandfluidityofliquidandsemi-liquidmaterials,shrinkageofmetalsandalloysdur-ingcoolingandsolidificationinliquid,semi-liquidandsolidstates,wettingandspreadingkineticsofliquidsonandoversurfacesofrefractorymaterials,infiltrationkineticsofliquidsin to porous materials, stability and reactivity of liquid metals and alloys in contact with re-fractorymaterials,gasificationofmaterialsduringtheirheatingorchemicalreactionintheexamined system at high temperature. The complex (Figs. 1a, b) is build on the concept of LEgO's blocks. It contains several apparatuses of own design having unique possibilities for complex materials characterization at high temperatures by different testing methods and various procedures or for simultaneous estimation of different characteristics in one test under high vacuumor flowing inert gas. Its central part presents the chamber fortransfer of the samples between different chambers and apparatuses without their open-ing and dehermetization, while the samples have no contact with air. Vacuum of 10-7-10-10 mbar is produced by turbomolecular and ionic pumps. The chamber for samples treatment and their surface characterization (chemistry, impurities, oxidation) is equipped with Auger spectro-meter and ion gun (for surface cleaning or for neutralization of electrical charge at the surfaces of ceramic samples). The main part of the complex is high temperature chamber(upto2100°C),workingunderhighvacuumorflowinginertgas;itisequippedwith quadropole residual gas analyzer (for characterization of gases formed during materi-als heating), manipulator for movement of experimental table in XY plane or its rotation up to270°,manipulatorfor loading,removalandtransferofthesamplesbetweendifferentchambers and apparatuses, manipulator located above the drop in order to transfer from the top an additional substrate or capillary with liquid metal, which can also squeeze metal throughcapillaryinordertorealizetheinsitudropcleaningfrominitialoxidefilmbycapil-larypurificationprocedureordispenseddropmethod. Besides classical sessile drop method, several improved testing methods and procedures can be applied (Fig. 1c). Among them such ones as the drop sucking, drop spreading,droppushing(dropmoving)havebeendeveloped for thefirst time.Severalexamples of high temperature wettability studies curried out with molten Sn, Al, Ni and Ti alloys are discussed in order to demonstrate wide testing possibilities of a new experimen-tal complex.

87


Fig. 1. a, b) Scheme of experimental complex design: 1- vacuum chamber for the first stage ofsample preparation by preheating in vacuum up to 200°C in order to remove adsorbed gases; 2- chamber for transferring the samples between the chambers using a manipulator that allows to bring the samples of different sizes and various shapes; 3- analytical chamber containing 3.1) Auger spectroscopefor surface characterization of examined materials before and after high temperature treatment, 3.2) ion beam foretching/cleaningsamplesand removalof surfacefilms fromexaminedsamples;4-portablecham-ber (vacuum “traveling-bag”) for storage and collection of specimens after testing under vacuum; 5- experi-mental chamber for high-temperature studies of materials in solid, semi-solid or molten states, containing 5.1) experimental table with rotation and up-and-down movement, the heater and screens with up-and-down movement, additional windows for observation and recording, 5.2) Quadropole residual gas analyzer for real time recording of chemical composition of vacuum, 5.3) capillary with up-and-down movement (for capillary purification procedure or for removal of a drop after testing, for example in order to “open” the interface/re-action products at the interface), 5.4) manipulator, located under a drop/substrate couple, which allows to delivery another substrate (sandwiched drop procedure) or alloying additions (in situ alloying in vacuum chamber), 5.5) automatic real-time temperature control by 4 thermocouples located in selected positions, c)testingmethodsandprocedures;c)methodsandproceduresthatcanbeappliedinanewcomplex

Acknowledgements: This work has been sponsored by the Ministry of Science and Higher Educa-tion of Poland and by the Foundry Research Institute under the projects No 4644/IA/425/2004 and No PBZ-KBN-114/T08/2004.

(c)

88


PS-1.10

InTERaCTIOn BETWEEn MOlTEn alUMInUM and COBalT OXIdE SInGlE CRYSTal

N. Sobczak1,W.Radziwiłł1, R. Nowak1, A. Kudyba1, J. Morgiel2, J. Wojewoda-Budka2

1Foundry Research Institute, 73 Zakopianska Str., 30-418 Krakow, Poland2Institute of Metallurgy and Materials Science, Polish Academy of Sciences,

25 Reymonta Str., 30-059 Krakow, Poland

Keywords: wettability, Al/CoO, reactivity, redox reaction, C4 composite structure

Wetting behavior and reactivity between molten aluminum and cobalt oxide single crystals wereinvestigatedbyasessiledropmethodinavacuumat800and1000°Cfor120minusingcon-tactheatingprocedure.ThesolidifiedsessiledropAl/CoOcoupleswerecross-sectionedandtheirmicrostructure were examined by optical microscopy in conventional and polarized light as well as by transmission electron microscopy (TEM) coupled with x-ray energy dispersive spectrometry (EDS).ThethinfilmsforTEManalysiswerepreparedusingfocusedionbeam.

At800°CmoltenAldoesnotwetCoOsubstrateandcontactangledecreases from initialvalueof110°toafinalvalueof104°after40min.For1000°Ctest, theinteractionintheAl/CoOcouple takes place during contact heating to experimental temperature resulting in the drop defor-mationthuscontributingtoapparentcontactangles.Thecontactangleof66°wasrecordedatthefirstmomentofreaching1000°Candinafewminutesitdecreasedto60°remainingconstantduringfurther holding at that temperature (Fig. 1).

Fig. 1. Wettability kinetics and vacuum level during wettability tests Al/CoO at 1000 and 700°C

Atbothtemperatures,AlreactswithCoObyredoxreaction(2Al+3CoO=3Co+Al2O3) ac-companied with the IMC formation resulting in the formation of thick reaction product region (RPR) ofinterpenetratingstructure,whichislocatedinsidethesubstrateunderthedrop(Fig.2);whenpro-duced at 1000ºC the RPR is also extended inside the drop (Fig. 3). Detailed TEM characterization (Figs. 2b, 3b-e) suggests that the redox reaction starts from the consumption of oxygen by Al from CoO,resultingintheformationofcontinuouslayerofpureCoattheCoO/RPRinterface.At1000°C,interaction in the Al/CoO couple results in pattering of RPR due to the formation of modulated oxide precipitation zone of periodic layered morphology (Fig. 3a). It might be caused from several compet-ing kinetic processes such as nucleation and growth rate of oxide and intermetallic phase precipi-tates, rejection rate of Co from reaction front and diffusion rates of Co, Al and O in each participating phase. The results obtained present experimental evidence that the Al/CoO system is a suitable can-didate for in situ synthesis of Al/Al2O3 composites of C4 structure by applying liquid phase reactive routes.Moreover,specificmechanismofinteractioninAl/CoOsystemallowstoproducematerialsofgradedorlayeredstructuresthusachievinghigherfunctionalityoffinalproducts.

T=1000ºC ♦ contact angle

vacuum

T=1000ºC

♦ contact angle

vacuum

89


Fig. 2. Microstructure of cross-sectioned Al/CoO couple (973 K): a) optical microscopy of interface; b) TEM view of RPR

a) b)

Fig. 3. Microstructure of cross-sectioned Al/CoO couple (1000°C):

a) optical microscopy of RPR; b) TEM view of RPR and corresponding

distribution of Al (c), Co (d) and O (e)

Acknowledgements: This work has been sponsored by the Ministry of Science and Higher Education of Poland under the project No PBZ-KBN-114/T08/2004.

a) b)

c) d) Al Kα Co Kα

O Kα e)

90


PS-1.11

EFFECT OF CaRBOn COaTInG On WETTInG and BOndInG OF al allOYS WITH al2O3 SUBSTRaTES

R. Nowak1, N. Sobczak1,2, W. Radziwill1, A. Kudyba1, A. Wojciechowski2, D. Rudnik2


Keywords: wettability, bonding, carbon coating, Al/Al2O3

The wettability of carbon-coated and uncoated polycrystalline Al2O3 (99.9%) sub-strates by molten Al and its binary alloys containing Ti, Si and Cu has been studied at 1273 K in vacuum by a sessile drop method using three testing procedure: CH – contact heating,CP–capillarypurification,andCP+DS–capillarypurificationwithdropsucking.Three types of carbon coating were used, i.e.:

1) Cgr – graphite coating deposited as a paste from a pencil,2) CPVD – covered by physical vapor deposition,3) Cs – soot coating produced by burning of candle.

The interface structure of the solidified sessile drop couples has been characteri-zed by optical and scanning electron microscopy coupled with EDS analysis. Mechanical strength of the drop/Al2O3 and drop/C/Al2O3 model joints has been determined using an improved push-off shear test directly on solidified sessile drop samples. Among selected materials a positive effect of carbon coating on alumina substra-tes on both wetting and bonding properties has been demonstrated with pure Al as well as with Al-Ti and Al-Si alloys (Table 1, Fig.1 a-b). The results have been explained by notable beneficial changes of interface struc-ture caused by chemical reactions between carbon layer and either Al or alloying element (Ti, Si) resulting in the formation of carbides Al4C3, TiC or SiC, respectively (Figs. 1d, 2).

Table 1. Final contact angle and shear strength for Al/C/Al2O3 systemsAlloy Ra, nm Procedure θ,° τ, MPa

Al/Al2O3 80 CP 94 42.11Al/Al2O3 80 CH 96 47.1

Al/Cgr/Al2O3 80 CP 90 59.95Al/CPVD/Al2O3 30 CH 79 56.72AlTi6/Al2O3 80 CH 103 17.81

AlTi6/Cgr/Al2O3 80 CH 52 42.83AlTi6/Cs/Al2O3 30 CH 17 -

AlTi6/CPVD/Al2O3 30 CH 18 -AlSi11/Al2O3 30 CH 84 66.19

AlSi11/CPVD/Al2O3 30 CH 125 82.62AlSi20/Al2O3 30 CH 99 32.44

AlSi22/CPVD/Al2O3 30 CH 69 25.43AlSi22/CPVD/Al2O3 30 CP 63 -

91


a) b) c)

Fig. 1. a-b) Side-views of Al/Al2O3 (a), AlTi6/Cgr/Al2O3 (b) and AlTi6/Cs/Al2O3 (c) couples produced by CH at 1273 K; d) SEM view of cross-sectioned AlTi6/Cgr/Al2O3 couple

Al3Ti

TiC

AlTi6 drop

al2O3PC

d)

Fig. 2. a) Scheme of sucking drop procedure applied after capillary purification and wettability test; b,c) side views of AlSi22/CPVD/Al2O3 couple after testing and drop sucking at 1273 K;

d) SEM view of the interface formed between AlSi22 drop and CPVD-coated Al2O3 substrate that was in situ opened by the drop sucking at testing temperature, showing the formation of SiC crystals at

the carbon-coated substrate

Acknowledgements: This work is sponsored by the Ministry of Science and Higher Education of Poland under the project No PBZ-KBN-114/T08/2004.

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PS-1.12

WETTInG and REaCTIVITY BETWEEn MOlTEn alUMInUM and ZInC OXIdE

N. Sobczak1, W. Radziwill1, A. Kudyba1, R. Nowak1, J. Oblakowski2

1Foundry Research Institute, 73 Zakopianska Str., 30-418 Krakow, Poland2AgH University of Science and Technology, 30-059 Krakow, Poland

Keywords: wettability, reactivity, Al/ZnO, redox reaction

The effects of testing procedure and substrate type (single crystal, polycrystalline) on the wettability and reactivity of liquid aluminum with the ZnO substrates were investi-gatedusingthesessiledropmethodinavacuumatatemperatureof700-1000°C. ThesolidifiedsessiledropAl/ZnOcoupleswerecross-sectionedandtheirmicro-

structure were examined by optical microscopy in polarized light as well as by scanning electron microscopy coupled with EDS analysis. Independently on the type of the ZnO substrates, temperature and testing proce-

dure, the results did not show wetting phenomenon (Table 1) despite experimental evi-dence of chemical reaction between liquid aluminum and ZnO leading to the formation of wettable reaction product Al2O3,(2Al+3ZnO=Al2O3 +3Zn). This reaction results in the growth of the interpenetrating reaction products region

(RPR), located in the ZnO substrate. It is composed of Al2O3 particles surrounded with Al(Zn) phase (Fig. 1). The RPR is characterized by C4 structure (Co-Continuous Ceramic Composite) as experimental evidence for recommendation of the Al/ZnO system for the in situ synthesis of Al/Al2O3 composites. Based on the detailed structural characterization of interfaces the recorded poor wettabilityofAl/ZnOcouples(finalcontactanglesθf>>90º) was explained by the phenom-ena of secondary substrate roughening and secondary drop oxidation taking place during wettability tests. Strong evaporation of reactively formed Zn was suggested to affect oxy-gen transport to the drop surface and thus contributing to the secondary oxidation effect.

Table 1. Results of wettability tests and thickness of reactive product region measured at AlZnO systems

ZnOsc – single crystal, ZnOpc – polycrystalline *-stepheatingatagiventemperature;#-timeatgiventemperature;&-finalcontactangleat1000°C

Substrate Procedure T(°C) t(min) p(hPa) θt(°)RPR(µm)

ZnOSC CH 700-800-1000* 40-10-55# 7.61×10-61.29×10-5 111& 70

ZnOSC CH 800 120 8.20×10-65.40×10-6 120 13

ZnOPC CP 750 120 1.09×10-55.47×10-6 124 ~ 0

ZnOPC CH 1000 10 2.67×10-51.99×10-5 141 ~ 2

ZnOPC CP 1000 30 2.71×10-52.43×10-5 122 34

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In case of polycrystalline zinc oxide substrates, the interaction in the Al/ZnOpc cou-ples is accompanied with strong reactive liquid metal penetration inside the substrate along grain boundaries. It results in the formation of the RPR of different thickness and phase composition, compared to single crystal substrates, since unreacted ZnO grains are surrounded with the reactively formed Al-Al2O3 layer of C4 structure (Fig. 2).

Acknowledgements: This work has been sponsored by the Ministry of Science and Higher Educa-tion of Poland under the project No PBZ-KBN-114/T08/2004.

Fig. 2. SEM image of cross-sectioned Al/ZnOsc (a) and Al/ZnOpc (b) couples after testing at 1000ºC showing the formation of reaction product region of C4 structure composed of large Al2O3 crystals surrounded with Al(Zn) alloy (a) and reactive liquid metal penetration along

grain boundaries (b)

a) b)

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PS-1.13

THEORETICal aSPECTS OF ORdEREd POROSITY METallIC MaTERIalS PROdUCEd BY UnIdIRECTIOnal SOlIdIFICaTIOn OF

GaS SaTURaTEd MElT

L. Drenchev1 , J.J. Sobczak2

1InstituteofMetalScience,67ShipchenskiProhodStr.,1574Sofia,Bulgaria2Foundry Research Institute, 73 Zakopianska Str., 30-418 Krakow, Poland

Keywords: modelling, ordered porosity, cast composites, gASAR, unidirectional solidification

Whereas ordered porosity materials have been extensively studied in the last de-cade in view of their unusual properties and potential applications, there has been a lack of fundamental understanding of their formation process.

This work is devoted to theoretical aspects of the formation of gASARs (gas rein-forced metals) also named as lotus type materials. For this group of ordered porosity ma-terialsproducedbyunidirectionalsolidificationofgassaturatedmeltitisnotclearwhetherthe porous structure obtained results from gas-eutectic reaction or it is produced by gas pore nucleation at a solid/liquid interface.

Different approaches for mathematical modelling of the basic physical processes involved in the gasar technology as well as corresponding relationships between process-ing parameters and structure characteristics will be discussed.

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InVESTIGaTIOn OF COMPOSITIOn and THERMOdYnaMIC CHaRaCTERISTICS OF al-BaSEd CaSTInG COMPOSITE

MaTERIalS

N.I. Ilinykh, V.E. Sidorov

Ural Technical Institute of Communications and Informatics Ural State Pedagogical University, Ekaterinburg, Russia

Keywords: Al-MMC, thermodynamic modeling, in situ composites

Nowadays Al-based casting composite materials reinforced with different disper-sed particles (carbides, nitrides, oxides etc.) become more and more popular. Their phy-sical and chemical properties can vary in a wide range and depend on production condi-tions. In order to make some prognoses, it is necessary to know thermodynamic characteristics of compounds as well as properties of the melts.

In the present work the thermodynamic modeling of equilibrium composition and properties of Al-Al2O3, Al-Al2O3-Ni, Al-Al2O3-Fe, Al-SiO2, Al-SiO2-Ni and Al-SiO2-Fe sys-tems was performed.

Themodelingwasmadeintheinitialgasatmospheresofargonandargon+airat common pressure of P = 105 Pa, and the content of Al2O3 (Al2O3+Ni(Fe))andSiO2 (SiO2 +Ni (Fe))additionswaschanged in the interval 0–50% (mass.).The investiga-ted temperature range was 700–2100 K. The following elements, compositions and ions (components of the systems) were taken into account at the modeling: gaseous Ar, O, O2, Al, Al2, AlO2, Al2O3,O3,O+,O2+,O-,O2+,Al+,Al2+,AlO-,AlO2-, N, N2, N3, NO, NO2, N2O, N2O3, Si, Si2, Si3, SiO2,SiO,Si+,N2O4, N2O5, AlN, NO2+,NO2-,N+,N2+,N2+,NO+,NO3AlO, Ni,NiО,Fe,FeO,FeO2,Fe+,е-andcondensedAl,Al2O3, AlN, Si, SiO2, Al2SiO5, Si3N4, Ni, NiO, NiAl, NiAl3, Ni2Al3, Ni3Al, Ni5Al3, Fe, Fe2O3, FeO, Fe3O4, FeAl2O4, FeAl, FeAl3, Fe2Al5, FeAl2, Fe2N, Fe4N.

From the results obtained for Al-Al2O3 system it comes that there is no chemical interaction between components of condensed phase. The exchange of aluminum atoms between matrix and doped elements seems very probable here. The temperature incre-ase from 700 to 2100 K practically does not influence on components behavior.

As for Al-SiO2 system, the existence of Al2O3, Al2SiO5 compounds was confirmed here, whereas the oxide SiO2 was not found.

The thermodynamic modeling for Al-Al2O3-Ni system predicts the conditions when the formation of Ni2Al3 and Ni5Al3 compounds can take place. Moreover, for the compo-sition50%Al+50%(x%Al2O3+y%Ni)thetemperatureandconcentrationintervalswiththe enlarged content of NiAl3 phase were determined.

The same results were obtained for Al-Al2O3-Fe system: the intervals with the increased content of FeAl3 and FeAl were determined.

All these results can be useful for prediction of casting optimal conditions and modifications in producing technologies.

PS-1.14

96


THE InFlUEnCE OF HEaT TREaTMEnT OF METallIC MElTS (HTM) On STRUCTURE and PROPERTIES OF SOlIdIFIEd

HYPO-EUTECTIC SIlUMInES

P. Popel, E. Rozhicina, I. Brodova, O. Chikova

Ural State Pedagogical University, Ekaterinburg, Russia

Keywords: processing, liquid metal treatment, structure, properties

The investigation of the influence of HTM on structure and properties of liquid steels was began in 1970th by B.Baum and coworkers. They were the first people who used property temperature dependences of liquid steels for optimization time-temperatu-re mode of melting. Steps in the development of HTM regimes:

Study of physical properties and structure of melt investigated in the course of its 1. heating and subsequent cooling and determination of characteristic temperatures Tc (homogenization temperature and/or temperatures corresponding to intermediate rearrangements).Laboratory melting of the alloy with heating the melt below and above Tc.2. Analysis of obtained samples structure and determination of an optimal HTM regime 3. at industrial production.Experimental industrial melting with HTM, analysis of solidified samples structure 4. before and after their heat treatment, comparison of service properties of alloys ob-tained using ordinary technology and HTM.Correction of the HTM regime basing on obtained results.5. Estimation of an efficacy of the new technology.6. We demonstrated in 1980th that after liquid Al-based alloys transition to the state

of a homogeneous solution:considerable over-saturation of the solid solution, •shift of the eutectic point to the region of larger concentration of the second compo-•nent, appearance of quasi-eutectic structure in samples with the hyper-eutectic composi-•tion, fragmentation of eutectic phases and initial crystals, •change of their morphology •

were revealed. Because of irreversibility of melt homogenization, one can cool homoge-nized system down to liquidus with any rate without waste of these effects.It would be very good to change primary aluminum alloys by secondary analogs. But secondary alloys have excess concentration of Fe, Mg, Cr, Ni, Zn at al. These impurities influence negatively on service properties of castings. That is why secondary alloys are of limited application in aircraft and automotive industries.

Iron is the most dangerous impurity in secondary silumines (more then 1%). Fe deteriorates castability, machinability, porocity, plasticity and durability of the alloys. It is a result of appearance of additional phases enriched by iron with a specific morphology. There are two kinds of Fe-based phases:

Primary crystals (long needles, plates or sceletons).1.

PS-1.15

97


Phases of eutectic origin (usually in grain boundaries).2. To improve quality of secondary aluminum-silicon alloys, it is necessary to decrease the volume fraction and the mean size of both kinds of the particles and to change forms of the primary crystals to more appropriate ones (for example, to “chinese script”).During fullfilement of our project that was supported by general Motors Corporation (USA) we have investigated the influence of HTM on service properties of secondary silumine. Our objects were alloys containing: (6.3-7.0)%Si, (1.0-1.2)%Fe, (0.27-0.40)%Mg, (0.21-0.37)%Mn and (0.18-0.35)%Cu. We measured viscosity and density temperature dependences of the alloys in liquid state at heating and subsequent cooling and discovered hysteresis of both the properties with branchingpointat960-1020°C.Regimesofmeltingandcasting:

Regimes

Temperature of melt heating Th, °C

Exposition at Th, min

Coolingrate, K/s

No.1 (ordinary) No.2 (ordinary) No.2 (experimental) No.3 (experimental)

74074011001100

20202020

~ 1~ 100~ 1~ 100

Castingtemperaturewasidenticalinalltheregimes(740°C).Asaresultoftheho-

mogenizing overheating the melt and following cooling with the rate of 1 K/s:primary crystals of Fe-rich phases becomes comparable in size with the same pha- -sesofeutecticorigin;volumefractionofFe-richphasesdecreasesfrom8%to6%; -microhardness of the a-solid solution grows from 760 up to 830 MPa. -

After cooling rate growth up to 100 K/s:volume fraction of Fe-rich phases decreases from 8% to 5.5% and their mean size -decreasesfrom30–50mmto8–10mm;microhardness of the a-solid solution grows from 760 up to 860 MPa. - Therefore, heat treatment of liquid secondary silumines is rather effective method

for their properties improvement. A similar method can be used for other alloys using our equipment for liquid alloys investigation.

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GRaPHITE TO 304SS BRaZE JOInInG BY aCTIVE METal BRaZInG TECHnIQUE - IMPROVEMEnT OF MECHanICal PROPERTY

A.K. Ray1, A. Kar1,2, S. A. Kori3, L. C. Pathak1, A. Sonnad3

1MST Division, National Metallurgical Laboratory, Jamshedpur 2 Advanced Joining Technology, EMPA-ETH Domain, Swiss Federal Laboratories,

Dübendorf, Switzerland,3R&D Centre, Dept. of Mechanical Eng., Basaveshwar Engg. College,

Bagalkot, Karnataka

Keywords: joining, graphite, SiC coating, mechanical property

Development of high strength graphite-304 stainless steel joint, using Ag-Cu-Ti filler alloy is studied in the present investigation. Due to excellent thermal shock resistan-ce, chemical inertness (except in oxygen at high temperature) good electrical and thermal conductivities, graphite is being used in various industrial applications, however due to its low mechanical strength its applications are restricted many fold. In aerospace it is being used in combination with metal. The mechanical properties of graphite are poor due to the presence of both open and closed porosities.

The mechanical property of the joint sample decreases further when filler metal goes into the pores of the graphite. Therefore, it is very difficult to achieve a high mecha-nicalstrengthforthegraphite-steelbrazejoint;ingeneralitvariesfrom10to15MPa.Inthe preset investigation a thin coating of SiC was applied on graphite.

Active filler alloy Ag-Cu-Ti was used to braze the substrates. The brazing were car-riedoutatanintervalof50°Cstaringfrom850°Ctill1000°C.Theinterfaceofthebrazejoints were characterized using SEM-EDS and XRD. From the correlation between struc-tural and mechanical property, we demonstrate improved shear strength i.e. ~35 MPa, for Graphite-304SSbrazejointproducedat900°C.

PS-1.16

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PS-1.17

InTERFaCE analYSIS OF YSZ-TO-METal BRaZES FaBRICaTEdWITH REaCTIVE FIllER METalS

O.A. Quintana, J.E. Indacochea

University of Illinois at Chicago, Materials Engineering Joining Science and Advanced Materials Research Laboratory, USA

Keywords: interfaces, characterization, YSZ

Solid Oxide Fuel Cells (SOFC) are potentially the most beneficial and robust alternatives for producing environmentally clean power. SOFCs utilize yttria stabilized zirconia (YSZ), an ionic conducting ceramic, as the active membrane (electrolyte) that produces the electrochemical poten-tial of the device under a chemical gradient to develop an electrical potential to generate electrical power. The major operation challenge of SOFCs is to produce a hermetic seal between the elec-trolyte and the ferritic stainless steel interconnect. The seals, besides being hermetic, must operate atelevatedtemperaturesthatmayreach850ºC;inaddition,theymustendurebothoxidizingandreducing conditions, and accommodate the mismatch in thermal expansion due to the dissimilar materials [1-5]. Zirconia is brittle and easily susceptible to cracking caused by the thermal stresses which limits the selection of the type of seals.

The fundamental issue of overcoming the seal challenge is to develop an efficient method to join the dissimilar materials. Current sealing methods for SOFCs include using glass sealants and compressive seals depending on the design and configuration of the fuel cell stack. glass se-als have the advantage of being cheap but also have an inherent problem of becoming brittle during the thermal cycling [2]. The solid oxide fuel cell is subject to stresses imposed by the different ther-mal expansion of the components and the glass seals do not yield. Ultimately the glass seals do not provide a solution for a long term 10,000 hr seal [4]. Compressive metal seals form a dynamic seal that conforms to the components and can handle the mismatch in thermal expansion coefficients, CTE. The objective of this work is to develop metallic seals between yttria stabilized zirconia (YSZ) electrolyte and Crofer-22APU® by metallic brazing.

It is recognized that the addition of titanium to commercially available filler metals promo-tes wetting of zirconia [6, 7]. The diffusion of titanium to the ceramic surface and its reaction with it controls the overall process. The reaction layer is the topic of many studies and understanding the mechanism and kinetics is complicated [5-8]. Thermodynamic analysis can show which pro-ducts are favorable during the process but only explain a portion of what is actually happening. For example, the reduction of zirconia, even at the high temperatures of brazing process by titanium, is thermodynamically unfavorable.

Our study focuses on investigating the formation and characterization of the reaction layer at the YSZ/braze metal interface using two different filler metal systems, as well as different levels of Ti for the sets of brazes produced.

Experimental Work A set of brazes of stainless steel to YSZ were fabricated using Ni and Ti foils. The Ti foil

was sandwiched between two thin Ni foils. The foil thickness and braze temperatures were selec-ted to produce a braze composition near the eutectic point based on the Ni-Ti. The other set of brazes were yttria stabilized zirconia disks (12.6 mm diameter/0.6-0.75 mm thick) brazed to 1.5 mm-thickCrofer22-APUsampleswith50-μmthickAg-Cu-Ti foils (CusilandTicusil fillermetals).All brazes were done under vacuum (6x10-6 torr). The brazes were cross sectioned and prepared metallographically to examine their joint quality, microstructure, and reaction layer characteristics particularly at the ceramic-metal interfaces. The local composition and reaction products present of the successful and failed samples were assessed using EDS, XRD, and the Advanced Photon Source (APS).

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Results

SoundbrazeswereobtainedwiththeNiTifillermetalwhenprocessingat1010°Cfor60minutes as seen in Fig. 1. An important finding at the braze metal/YSZ interface was the lack of a familiarreactionlayer;insteadfinesecondphasenoduleswereattachedtotheceramicsubstratethat grow perpendicular to the interface, as seen in Fig. 2. The lack of the reaction layer might be due to ZrO2 being very stable and not easily reduced by Ti since TiO2 is less stable. Yet there must besomesortofinteractionatthisinterfacesinceanα-Timatrixofthebrazemetalhasbondedtothe YSZ. The interfaces at either side of the braze metal have been carefully analyzed.

All YSZ-Ticusil®-YSZbrazesmanufacturedat900°Cbondedwellandthecrosssectionsare shown in Fig. 3. Two filler metals were used in this part of the study, Cusil ABA® and Ticusil®;both have Ti as reactive metal, the later one has a larger content of Ti. This difference impacted on the thickness and density of the reaction layers (Fig. 4).

Fig. 3. YSZ-Ticusil®-YSZ brazes made at 900°Cforbrazingtimesof(a)30’, and

(a) (b)

Fig. 3. YSZ-Ticusil®-YSZ brazes made at 900°C for brazing times of (a) 30 min, and (b) 60 min

0

1

2

3

4

5

6

7

0 10 20 30 40 50 60 70 Time (min)

Reac

tion

laye

r thi

ckne

ss (μ

m)

Cusil® Ticusil®

Fig. 4. Reaction layer thickness as function of brazing timeat900°Cfor YSZ-Cusil-ABA®-YSZ & YSZ-Ticusil®-YSZ brazes.

Fig. 1. Optical micrograph of braze cross section fabricated at 1010°C for 60 min

Fig. 2. SEM micrograph of braze cross section produced at 1010ºC for 60 min

Fig. 4. Reaction layer thickness as function of brazing time at 900°C for YSZ-Cusil-ABA®-YSZ &

YSZ-Ticusil®-YSZ brazes

The results of the Ag-Cu-Ti filler metal brazes imply that the increase in the Ti level enhances the formation of the reaction layer. In the case of the Ni/Ti filler metal system, initial expectation wasthatadenserandlargerreactionlayerwouldappear;however,asvirtuallynoreactionlayerdeveloped.

ReferencesF.Tietz, H.P. Buckkremer, and D. Stover, Solid State Ionics. (2002) 152-153, pp. 373-381.1. S. P. Simner and J. W. Stevenson, Journal of Power Sources. (2001) 102, pp. 310-316.2. D. Sciti, A. Ballios, and L. Esposito, Journal of the European Ceramic Society. (2001) 21, pp. 45-52.3. K.S. Weil, C.A. Coyle, J.T. Darsell, g.g. Xia, and J. S. Hardy, J. Power Sources (2005).4. H.Q. Hao, Y. L. Wang, Z. H. Jin, and X. T. Wang, Journal of Materials Processing Technology. (1995) 52, 5. pp. 238-247.M. Paulasto, g. Ceccone and S. D. Peteves, Scripta Materialia. (1997) 36 No. 10, pp. 1167-1173.6. M. ghosh, S. Das, P.S. Banarjee, and Chatterjee, Materials Science and Engineering A. (2005) 390, pp. 7. 217-226.

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PS-1.18

SURFaCE TREaTMEnT OF THE alUMInIUM MaTRIX COMPOSITE MaTERIalS WITH COnCEnTRaTEd ElECTRIC dISCHaRGE In

MaGnETIC FIEld

T.A. Chernyshova1, R.S. Mikheev1, A.M. Rybachuk2

1Russian Federation, Moscow, A.A. Baikov Institute of Metallurgy and Materials Science of Russian Academy of Sciences, Leninsky prospect, 49, Russia

2Russian Federation, Moscow, Bauman Moscow State Technical University, 2-ya Baumanskaya, 5, Russia

Keywords: Al-MMC, surface treatment, electric arc melting, magnetic field, wear-resistance, microstructure

Production of the wear resistant surface layers is an urgent task during fabri-cation and repair of machine elements. Thermomechanical, arc, laser ray and plasma methods of the surface treatment of metal workpieces are widely used in an industry [1]. The possibility of using of an electric arc melting in a magnetic field for wear-resi-stant improving of the surface layers of cast composite materials (CM) based on Al-12Si-2Cu-1Mg-1Ni alloy reinforced with silicon carbide particles (Vp=12%) have been studied in this work. Al-12Si-2Cu-1Mg-1Ni alloy can be considered as the model for estimating of the structure modifying effects, because it is well-known that the changing of the silicon crystal sizes in antifriction Al-Si alloys has the appreciable effect on their wear-resistance [2]. The surface melting of the cast CM plates was done by argon arc discharge with nonfusible cathode under continues current. Electric arc was in the centre of the four-polar magnetic system. Combined action of the lateral and transversal magnetic fields defines compression ratio of the electric arc, its penetration ability and consequently depth and wide of the melted zone [3, 4]. In addition the volumetric elecrodynamic forces directed at the surface of the workpiece appear in the melted zone. The volumetric electrodynamic force values appeared during the interaction of Foucault currents with magnetic field of the system are adjusted by changing of current values in the magnet winding.The microstructure of the modified surface layers was researched with optical microsco-pe Leica DMILM. Mechanical properties were defined by microhardness measurement using Wilson Wolpert 432SVD under the load of 0.05 kg. Dry sliding wear tests of the ini-tial cast and treated samples were carried out to estimate the modification efficiency. The tests were realized according to scheme: bush (counterface, quenched steel, HRC>45) on disk (CM sample) under constant axial loads (from 18 up to 60 N) and at sliding speed of 0.39 m*s-1. The results have shown that an increase in the magnetic induction values from 0.048 T to 0.12 T increases the width decreases the depth of the surface layers produced by arc melting in magnetic field. This effect is the result of the electric discharge defocu-sing increasing. The microstructure analysis has shown that after the treatment an eutectic spa-cing of the matrix alloy decreases more than five times. The considerable structure di-spersion was generated by high cooling rates peculiar to an electric arc process. The

102


structure dispersion is smaller near the weld line. It is the result of partial inheritance of the substrate structure during the epitaxial crystallization. The modified layer is characterized by a quite uniform microhardness distribution. The microhardness of the layers produced by arc melting in magnetic field increases more than 20% of the initial values. The magnetic induction changing almost did not influ-ence on the modified layer microhardness. The results of dry sliding wear tests of initial cast and modified samples have shown that the modification of the surface layers leads to significant improving of tribo-technical characteristics: wear rate decreases about two times. The friction coefficient va-lues of the modified samples are smaller than ones of the initial samples. The subsurface layers undergo the intense plastic deformation during dry sliding wear. Their tracks can be observed in cross section of the samples after dry sliding wear tests. Transition layer composed of dispersed mechanical mixture from counterface and sample materials and their oxides is formed on the contact areas. The transition layer promotes to decrease friction coefficient and wear rate of the samples.

References

M.V. Atamanov, V.I. Vasil’ev, V.V. Zaicev, V.A. Ivanov, O.N. Karuzin, N.V. Pleshivcev, V.N. Prohorov, 1. N.E. Chaschin: The new technologies of strength improvement of mashine parts, Avtomobil’nyi transport, 1995, No 7, pp. 31-33.S.B. Stroganov, V.A. Rotenberg: gershman g.B., Al-Si alloys, Moscow, Metallurgia, 1977, p. 272.2. A.I. Akulov, A.M. Rybachuk: The keeping of melt metal in welding pool by transversal magnetic field, Sva-3. rochnoeproizvodstvo,1972,No2,с.3-4.A.M. Rybachuk: The weld bead formation by magnetic field, Svartchik professional, 2005, No 5, pp. 9-10.4.

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GENERAL SESSION

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105


general session11.00-11.15 Introduction to the activities of the Foundry Research InstituteJ.J. Sobczak

11.15-11.35advanced techniques for structural characterization at MCITiM M. Faryna

11.35-12.00 The mystery of molten metals: methodological, scientific and practical aspects of high temperature studies of metal/ceramic interactionsN. Sobczak

12.00-13.30 Visit to laboratories of the Foundry Research Institute

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adVanCEd TECHnIQUES FOR STRUCTURal CHaRaCTERIZaTIOn aT MCITIM

M. Faryna

Institute of Metallurgy and Materials SciencesPolish Academy of Sciences

Reymonta 25 30-059 Krakow Poland

Keywords:

The lecture will be dedicated to the new scanning electron microscope purcha-sed in the frame of the MCITiM program. The Quanta 3D FEg is the most versatile high-resolution, low vacuum scanning electron microscope for 2 dimensional and 3 dimensio-nal material characterization and analysis. Innovative electron and ion optics combined with environmental SEM operating mode expand laboratory capabilities, providing bet-ter, faster and more comprehensive materials characterization. A novel, field-emission electron source delivers clear and sharp electron ima-ging. Increased electron beam current enhances both Energy Dispersive Spectrometry (EDS) and Electron Backscatter Diffraction (EBSD) analysis. Featuring three imaging modes i.e.: high-vacuum, low-vacuum and ESEM (environmental mode), the microsco-pe accommodates the widest range of samples of any SEM system. The Quanta 3D FEg has been designed to provide the widest range of data – imaging and microanalysis – from all specimens, with or without preparation. The micro-scope enables also a fast material removal for accurate cross-sectioning featuring live SEM imaging while milling. The attached ion column of ultimate parameters makes 3D analysis of morphology, chemical composition and orientation topography available.

107


THE MYSTERY OF MOlTEn METalS: METHOdOlOGICal, SCIEnTIFIC and PRaCTICal

aSPECTS OF HIGH TEMPERaTURE STUdIES OF METal/CERaMIC InTERaCTIOnS

N. Sobczak


Keywords: high-temperature phenomena, molten metal, in situ observation

Many important techniques of materials processing require the contact betwe-en molten metals and refractory materials (i.e. casting processes, liquid metal handling, joining ceramics, fabrication of metal-ceramic composite materials) when the resulting properties of final products are closely related to high-temperature properties of a liquid metal and, particularly, high-temperature surface and interfacial phenomena. Thus the interaction between a liquid metal and a solid material and the nature of interfaces for-med play a key role in selecting suitable material or processing parameters, particularly important for development of metal-ceramic composites by liquid phase route. Since at high temperature everything reacts with everything, such interactions can be accompanied by a number of complex chemical reactions at liquid metal/atmo-sphere and liquid metal/solid interfaces, leading to significant changes in interface struc-ture and chemistry thus affecting the properties of manufactured goods. Therefore, it is highly desirable to develop experimental techniques and equipment allowing in situ observation that helps in understanding of high-temperature phenomena taking place in liquid and semi-liquid alloys. The presentation will focus on the research activities of the Centre for High Tem-perature Studies at the Foundry Research Institute in Krakow (Poland) in the field of high-temperature liquid state materials science. Special attention will be paid to technical and methodological aspects of experimental apparatuses of own design as well as their unique research opportunities. Several examples of real-time observation of high-temperature behavior of diffe-rent materials will be discussed. The movies will be demonstrated in order to show the mystery hidden in liquid metals that is caused by numerous high-temperature phenome-na taking place during processing of cast metal-ceramic composites and affecting the quality of final products, i.e.:

liquid metal wettability, spreading and infiltration, •the formation of porosity due to the formation of gaseous reaction products or gasifi-•cation from ceramic material,liquid metal shrinkage or expansion, •the formation of undesirable nonmetallic inclusions, •the change in dimensions of ceramic preforms due to high reactivity between molten •metal and ceramic,secondary liquid metal oxidation,•secondary ceramic substrate roughening due to whiskering effect. •

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(alphabetically)list of authors

aAgathopoulos S. 24Aniszewska D. 64Asthana R. 16BBallmes H. 58, 62Bielinski J. 60, 62Boczkowska A. 56, 60,62Broda A. 60Brodova I. 96Budzioch J. 86CChernyshova T.A. 101Chikova O. 96Cholewa M. 46Czulak A. 56, 62

dDarlak P. 19, 27, 31, 40, 42, 77Dolata-grosz A. 33, 60, 62Drenchev L. 27, 94Dyzia M. 60, 62EEgbert A. 30Egizabal P. 21Engelmann F. 56, 62FFaryna M. 106

Ggarcía R.A. 21glenz A. 86gude M. 56, 60, 62HHoma M. 19, 35, 79, 84Hufenbach W. 56, 62IIlinykh N.I. 95Indacochea J.E. 99

JJaegermann Z. 71KKaczmar J.W. 44Kar A. 98Karantzalis A.E. 18Karwinski A. 79Klasik A. 73Kondracki M. 46Kori S.A. 98Kozera R. 60, 62Kudyba A. 19, 49, 62, 79, 88, 90, 92Kurzydlowski K.J. 60, 62lLasota P. 42Latallo-Anulewicz M. 37Lech-grega M. 35, 75Lekatou A. 18Leontaris K. 18Lesniewski W. 27, 79MMichalski R. 31Mikheev R.S. 101Morgiel J. 25, 44, 51, 88Muolo M.L. 48Myszka D. 81nNaplocha K. 44Nowak R. 51, 53, 79, 82, 84, 86, 88, 90, 92OOblakowski J. 92Ozieblo A. 71PPasserone A. 48Pathak L.C. 98Pietrzak K. 42, 44, 77Pomorska M. 25, 44Popel P. 96Przetakiewicz W. 42Purgert R.M. 40, 84

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QQuintana O.A. 99RRadziwill W. 82, 86, 88, 90, 92Ray K. 98Rottmair C.A. 58, 62Rozhicina E. 96Rudnik D. 31, 42, 77, 90Rybachuk A.M. 101Rybaczuk M. 64SSidorov V.E. 95Sienicki E. 53, 79, 82, 84Siewiorek A. 49, 62Singer R.F. 58, 62Sleziona J. 60, 62Sobczak J.J. 16, 19, 27, 31, 40, 42, 73, 77, 94Sobczak N. 16, 19, 25, 35, 40, 49, 51, 53, 60, 73, 79, 82, 84, 86, 88, 90, 92, 107Sonnad A. 98Stobierski R. 53Szymanski W. 75TTorregaray A. 21VValenza F. 48WWieliczko P. 27Wojciechowski A. 31, 40, 42, 73, 77, 90Wojewoda-Budka J. 51, 88ZZieba P. 35Zybura M. 35

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agathopoulos Simeon,University of Ioannina, greeceantosiewicz anna, Foundry Research Institute, Krakow, Polandasthana Rajiv, University of Winsconsin, USABalcerek Wojciech, Foundry Research Institute, Krakow, PolandBallmes Heiko, University Erlange-Nuremberg, germany Boczkowska anna, Warsaw University of Technology, PolandBruzda Grzegorz, Foundry Research Institute, Krakow, PolandCholewa Miroslaw, Silesian University of Technology, gliwice, PolandCzulak andrzej, Technische Universitaet, Dresden, germanydarlak Pawel, Foundry Research Institute, Krakow, Polanddolata-Grosz anna, Silesian University of Technology, Katowicedrenchev ludmil, Bulgarian Academy of Science, Bulgariadyzia Maciej, Silesian University of Technology, KatowiceEgbert andre, gE Sensin & Inspection Technologies gmbH, germany Egizabal Pedro, Fundacion Inasmet-Tecnalia, SpainEngelmann Frank,Technische Universitaet, Dresden, germany Gude Maik,Technische Universitaet, Dresden, germanyHyla Izabella, Silesian University of Technology,Katowice, PolandIlinykh nina, Ural Technical Institute of Communications and Informatics, RussiaJaszczolt Katarzyna, Foundry Research Institute, Krakow, PolandJaworska lucyna,The Institute of Advanced Manufacturing Technology, Krakow, PolandKaczmar Jacek W., Wroclaw University of Technology,PolandKaleta Jerzy, Wroclaw University of Technology, PolandKarantzalis aleksander, University of Ioannina, greeceKarwiński Aleksander, Foundry Research Institute, Krakow, PolandKlasik adam, Motor Transport Institute, Warsaw, PolandKlyszewski andrzej, Institute of Non-Ferrous Metals, Skawina, PolandKorpała Bartlomiej, Foundry Research Institute, Krakow, PolandKozera Rafal, Warsaw University of Technology, Warsaw, Poland latallo-anulewicz Marcin, Foundry Research Institute, Krakow, Polandlech-Grega Marzena, Institute of Non-Ferrous Metals, Skawina, Polandlesniewski Wojciech, Foundry Research Institute, Krakow, PolandMadej Joanna, Foundry Research Institute, Krakow, PolandMikheev Roman, Russian Academy of Sciences, Moscow, RussiaMorgiel Jerzy, Polish Academy of Sciences, Krakow, PolandMuolo Maria l., Istituto per l'Energetica e le Interfasi, genova, ItalyMyszka dawid, Warsaw University of Technology, Polandnowak Rafal, Foundry Research Institute, Krakow, PolandOziebło Artur, Institute of glass, Ceramics, Refractory and Construction Materials, Warsaw, PolandPasserone alberto, Istituto per l'Energetica e le Interfasi, genova, ItalyPiatkowski andrzej, Polish Academy of Sciences, Krakow, Poland Pietrzak Krystyna, Motor Transport Institute, Warsaw, Poland Przetakiewicz Wojciech, Motor Transport Institute, Warsaw, Poland

list of PARTICIPANTS(alphabetically)

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Purget Robert M., Energy Institute of Ohio, USARegula Tomasz, Foundry Research Institute, Krakow, PolandRottmair Christian a., University Erlange-Nuremberg, germanyRudnik dariusz, Motor Transport Institute, Warsaw, PolandRybaczuk Marek,Wroclaw University of Technology, PolandSidorov Valery, Ural State Pedagogical University, Ekaterinburg, RussiaSienicki Edmund, Motor Transport Institute, Warsaw, PolandSiewiorek aleksandra, Foundry Research Institute, Krakow, PolandSobczak Jerzy J., Foundry Research Institute, Krakow, PolandSobczak natalia, Foundry Research Institute, Krakow, PolandSuchy Jozef Sz., AgH University of Science and Technology, Krakow, PolandSypien anna, Polish Academy of Sciences, Krakow, PolandSzymanski Wojciech, Institute of Non-Ferrous Metals, Skawina, PolandSleziona Jozef, Silesian University of Technology, Katowice, PolandTrzcinski daniel, PB Technik Ltd, Warszawa,Wojciechowski andrzej, Motor Transport Institute, Warsaw, Poland Wojewoda-Budka Joanna, Polish Academy of Sciences, Krakow, PolandZieba Pawel, Polish Academy of Sciences, Krakow, PolandZietek Grazyna,WrocławUniversityofTechnology,PolandZybura Maria, The Institute of Advanced Manufacturing Technology, Krakow, Poland

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Note Book

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Documents

Cast Conference 2009