International Conference on Challenges and Opportunities in Mechanical Engineering, Industrial Engineering and Management Studies 16

(ICCOMIM - 2012), 11-13 July, 2012

ISBN 978-93-82338-03-1 | © 2012 Bonfring

Abstract--- The demand of today’s and future aluminium alloys are best suitable materials in engineering

applications. Now day’s rapid changes in the materials, they are looking towards weight reduction and low cost

materials like aluminum alloys and its composites. The present study reveals the effect of thermal behavior in the

aluminum alloys especially Al-12%Si (LM13) matrix material and Al-12%Si / Magnesium oxide composites. The as-

cast Al-12%Si (LM13) alloy and its composites were fabricated using stir-casting method by varying the

reinforcement content from 0 wt.% to 10 wt.% in steps of 2. The specimens were prepared as per ASTME standards.

The samples were subjected to solutionizing at a temperature 5100c for duration of 2 hrs followed by Ice quenching

media & then the samples were heat treated at temperature 1900c for 6hrs. The thermal conductivity of as-cast and

heat treated alloy and its composites were tested and the result reveals that the thermal conductivity of as-cast and

heat treated alloy and its composites was decreases as the reinforcement content increases. These composites may

be the alternate materials for spacecrafts & aero-plane components, automobile parts like piston rod, connecting

rod & cylinder head.

Keywords--- LM 13, MgO, Stir-Casting Method, MMC’s, Thermal Conductivity.

I. INTRODUCTION

OW days, the world-wide upsurge in MMCs research and development activities is focusing mainly on

Aluminium and its alloys. Because of its unique combination of properties like, good corrosion resistance, low

density and excellent mechanical properties. The unique thermal properties of Aluminium composites such as

metallic conductivity with coefficient of expansion, that can be tailored down to zero and are used in aerospace and

avionics1-5

. LM13/quartz was studied by Joel hemanth6 & Norman tommis

7 were also studied & received patent

award in US. They explained details of light metals properties of LM13/zicronia and thermal properties were

studied. Successful developments of MMCs are critical in reaching the goals of many advanced aerospace

propulsion and power development programs. The specific space propulsion and power applications require high

temperature; higher thermal conductivity and high strength materials. MMCs either fulfil or have the potential of full

filling these requirements and also offer considerable promise to help automotive engineers to meet the challenges

of future & current demands8-10

. LM13 based MMCs refer to the class of light weight materials suitable in

applications where weight reduction has first priority.

The as-cast Al-12%Si (LM13) alloy and its composites were fabricated using stir-casting method by varying the

reinforcement content from 0 wt.% to 10 wt.% in steps of 2. The properties of LM13 based MMCs can be tailored to

the demands of different industrial applications by suitable combination of reinforcements & processing route9-11

.

II. EXPERIMENTAL SETUP

The matrix material selected was Al-12%Si (LM13) and reinforcement material was MgOp and particles were

dispersed in the matrix material and chemical composition is as shown in Table 1 11-12

. The size of the MgO

particulates dispersed varies from 5 to 8 µm. The chemical composition of the reinforcement is shown in table 2.

G.K. Ananda, Student, Department of Mechanical Engineering, Sri Siddhartha Institute of Technology, Maralur Post, Tumkur 572105, India.

E-mail: ananda_gk@roketmail.com C.S. Ravindra Sagar, Department of Mechanical Engineering, Sri Siddhartha Institute of Technology, Maralur Post, Tumkur 572105, India

T.K. Chandrasekhar, Professor, Department of Mechanical Engineering, Sri Siddhartha Institute of Technology, Maralur Post, Tumkur

572105, India

PAPER ID: MED03

Studies on Thermal Behaviour of Lm13/ MGOP

Metal Matrix Composites G.K. Ananda, C.S. Ravindra Sagar and T.K. Chandrasekhar

N

International Conference on Challenges and Opportunities in Mechanical Engineering, Industrial Engineering and Management Studies 17

(ICCOMIM - 2012), 11-13 July, 2012

ISBN 978-93-82338-03-1 | © 2012 Bonfring

Table 1: Chemical Composition of LM13 Alloy

Si Mg Cu Fe Ti Ni Mn Al

12.1 1.2 0.8 0.8 0.02 0.9 0.2 84.30

Table 2: Chemical Composition of MgOP

Magnesium oxide Silica

75% 20%

The as-cast Al-12%Si (LM13) alloy and its composites were fabricated using stir-casting method by varying the

reinforcement content from 0 wt.% to 10 wt.% in steps of 2. The matrix material was first superheated to above its

melting temperature and preheated reinforcement particulates were added into molten metal. The molten metal was

stirred for duration of 8 min using a mechanical stirrer and speed of the stirrer was maintained at 450 rpm. The melt

at 750°C was poured into the pre-heated cast iron dies. The castings were tested to know the common casting

defects using ultrasonic flaw detector. The specimens were prepared as per ASTME13-15

standards and the samples

were subjected to solutionizing at a temperature 5100c for duration of 2 hrs followed by Ice quenching media & then

the samples were heat treated at temperature 1900c for 6hrs

16-18.

The thermal conductivity test was conducted on the as-cast and heat treated composites. The surface of the

specimens were cleaned by alcohol and then by acetone to remove the dust particle. Then the specimen in mounted

in the testing column and the temperature is increased to 500c by heat input and once the temperature attains

equilibrium condition, the thermocouple readings were recorded. The procedure was repeated up to 2000c in steps of

500c. The thermal conductivity of the specimen was calculated by using the principle of Fourier‟s law of conduction

at steady state operating condition with unidirectional heat conduction. The experiment was repeated thrice for each

specimen and the average value was taken.

III. RESULT & DISCUSSION

3.1 Thermal Conductivity (K)

In general, the heat transfer in which energy exchanged between the high temperature region to lower

temperature region due to kinetic motion or direct impact of molecules. due to Fourier law of conduction.

P.L.Balley19-20

, Studies on conduction & showed that thermal conductivity of the MMCs depends on the size &

shape of the reinforcement. This benefits the presents investigation in that lower thermal conductivity due to

addition of MgOP as reinforcement results in lower heat loss from engine resulting in an increase in the thermal

efficiency.

Figure 1: Effect of Temperature Rise on Thermal Conductivity for Different Wt% of Reinforcement

International Conference on Challenges and Opportunities in Mechanical Engineering, Industrial Engineering and Management Studies 18

(ICCOMIM - 2012), 11-13 July, 2012

ISBN 978-93-82338-03-1 | © 2012 Bonfring

Thermal conductivity results obtained at different temperature for cast MMCs of LM13 with different volume %

of dispersoid contents. It can easily observed results fig1.Thermal conductivity decreases as dispersiod content &

temperature increasing. From this come to know that thermal conductivity mainly depends on temperature

distribution & what type of use reinforcement & heat treatment process are carried out casted LM13 Material.

Comparing both heat treatment & as cast of LM13/MgOp in above fig1& fig 2. It clearly indicates that value of

thermal conductivity is decreases with increases temperature & also increase in wt.% of reinforcement. Due to

ageing of the material, it becomes hardening so it looses its thermal conductivity value as compare to as-cast

LM13.It also depends upon type of material & reinforcement. Since temperature in the substance varies in the

course of heat propagation, it is important to find out how thermal conductivity depends on temperature.

Experiments shows that for most materials, they dependence is linear.

i.e K=k0(1+at)

Figure 2: Effects on Temperature Rise on Thermal Conductivity for Different wt% of Reinforcement

IV. CONCLUSION

The following conclusions were drawn from the above study,

1. The LM 13/ MgO composites were fabricated successfully in stir-casting technique.

2. The thermal conductivity of the alloy is maximum as compared to composites. The thermal conductivity of

the alloy decreases as the reinforcement content increases.

3. The thermal conductivity of alloy and its composites decreases as the heat input increase and also thermal

conductivity decrease for the heat treated alloy and its composites.

4. The thermal conductivity composites developed is slightly less than of the matrix material.

5. The addition of reinforcement results in lower heat loss from the engine resulting in increasein the thermal

efficiency.

REFERENCE

[1] G. Ondracek, Werkstoffkunde: Leitfaden für Studium und, Expert-Verlag,Würzburg (1994).

[2] TechTrends, International Reports on Advanced Technologies: Metal Matrix Composites: Technology and

Industrial Application, Innovation 128, Paris(1990).

[3] T. W. Clyne, P. J. Withers, An Introduction to Metal Matrix Composites, Cambridge University Press,

Cambridge(1993).

[4] K.U.Kainer, Keramische Partikel, Fasern und Kurzfasern für eine Verstärkung von metallischen

Werkstoffen.MetallischeVerbundwerkstoffe,K.U.Kainer(Ed.),DGM Informationsgesellschaft,Oberursel (1994),

pp. 43–64.

International Conference on Challenges and Opportunities in Mechanical Engineering, Industrial Engineering and Management Studies 19

(ICCOMIM - 2012), 11-13 July, 2012

ISBN 978-93-82338-03-1 | © 2012 Bonfring

[5] J. Schröder, K. U. Kainer, Magnesium Base Hybrid Composites Prepared by Liquid state fabrication, Mater.

Sci. Eng., A 1991, 135, 33–36.

[6] Joel Hemanth. Quartz(SiO2p) reinforced chilled metal matrix composite for automotive applications,2008 30

V323-329

[7] Norman tommis,bradford,composition of matter and their manufacture Nov 25 1986,recived U.S patent

No.3,625,676

[8] Schulte in Metal Matrix Composites -Processing Microstructure and Properties,N. Hansen et al. (Ed.), Risø

National Laboratory, Roskilde (1991), pp. 429–434.

[9] J. Janczak et al., Grenzflächenunter-suchungen an endlosfaserverstärkten Aluminum matrix

Verbundwerkstoffen für die Raumfahrttechnik, Oberflächen Werkstoffe (1995) Heft 5.

[10] Lloyd D J 1999 Particle reinforced aluminium and magnesium matrix composites. Int. Mater. Rev.39: 1–23.

[11] Maruyama B 1998 Progress and promise in aluminium metal matrix composites. The AMPTIAC NewsLett.

2(3):

[12] Smithells Light Metals Handbook E. A. Brandes CEng, BSc(Lond), ARCS, FIMandG. B. Brook DMet(Sheff),

FEng, FIM

[13] John L., Jorstad (September 2006), "Aluminum Future Technology in Die Casting", Die Casting Engineering:

18–25, archived from the original on 11-12-2010,

[14] NADCA Product Specification Standards for Die Castings / 2006

[15] Liu, Wen-Hai (2009-10-08), The Progress and Trends of Die Casting Process and Application, archived from

the original on 2010-10-19,

[16] Avedesian, M. M.; Baker, Hugh; ASM International (1999),

[17] Magnesium& magnesium alloys (2nd ed.) ASM International,p.76, ISBN 9780871706577

[18] Davis, J. (1995), Tool Materials, Materials Park: ASM International, ISBN 9780871705457.

[19] P.L.Balley Thermal engineering, khanna publishers Delhi p272-275

[20] Heat & mass transfer, Dr.D.S.Kumar, S.k. kataria & sons sixth edition 2003 p1-10

[21] Ozkan Sarikaya “The effect on residual stresses of porosity in plasma sprayed MgO–ZrO2 coatings for an

internal combustion diesel engine” Vol 11-16, 2008

[22] J.M. Molina” The eff ect of porosity on the thermal conductivity of Al–12 wt.% Si/SiC composites” 2008 Vol

582-5586

[23] L.N. Thanh, M. Suery, Influence of oxide coating on chemical stability of SiC particles in liquid aluminum,

Scripta Metall. Mater. 25 (1991) 2781–2786.

[24] M. Huang, X. Li, H. Yi, N. Ma, H. Wang, Effect of in situ TiB2 particle reinforcement on the creep resistance

of hypoeutectic Al–12Si alloy, J. Alloys Comp. 389 (2005) 275–280.