WEAR BEHAVIOUR OF ALUMINIUM METAL MATRIX …

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WEAR BEHAVIOUR OF ALUMINIUM METAL MATRIX COMPOSITES

REINFORCED WITH COPPER AND GRAPHITE

B. N. V. SRINIVAS1, K. DORATHI2, Dr. N. TULASI RADHA3 & G. RAMAPRASAD4

1,2,4Assistant Professor, Department of Mechanical Engineering, Sri Vasavi Engineering College, Tadepalligudem, Andhra

Pradesh, India

3Scholar, Department of Mechanical Engineering, GITAM University, Visakhapatnam, Andhra Pradesh, India

ABSTRACT

A low cost system of Al 6063 4%Cu xGr (x = 2, 4 and 6 wt. %) metal matrix composites (MMCs) were fabricated by stir

casting technique. These fabricated composites were characterized by using scanning electron microscope. The dry sliding

wear behaviour of the prepared composite was investigated by using a Pin on Disc method at applied loads of 50 N. Wear

tests were carried out with no lubrication at room temperature (30–36°C). The ageing of the MMCs was done followed by

air cooled and water cooled. The results indicate that the wear rate is less for Al4CU4Gr air cooled.

KEYWORDS: Al6063, Stir casting, Graphite, Copper, Metal matrix composites, Wear & Ageing

Received: Jun 10, 2020; Accepted: Jun 30, 2020; Publibshed: Aug 31, 2020; Paper Id.: IJMPERDJUN2020990

1. INTRODUCTION

Discontinuous reinforced aluminum metal matrix composites (DRAMMCs) are a class of composite materials with

desirable properties, including low density, high specific rigidity, high specific strength, controlled thermal

expansion co-efficient, increased fatigue resistance and superior dimensional stability at high temperatures,

etc.[1,2]. Such materials have emerged as the essential class of advanced materials that offer the ability for

engineers to adapt the material properties to their needs. Such materials fundamentally vary from the typical

manufacturing materials from the homogeneity point of view. Controlled application of one or more reinforcement

materials in continuous metal matrix process is possible in composites. The vast majority of these composite

materials are metallic components reinforced with high strength, high modulus and brittle ceramic phases which can

be either continuous in the form of fibre, discontinuous in the form of whiskers,

Platelets or particulate reinforcements embedded in a matrix [3-6]. Over the past two decades, wear

performance of DRMMCs

Reinforced with various reinforcements ranging from very soft materials such as graphite, talc etc. to

highly hardened ceramic particles such as SiCp, Al2O3 etc., [3 – 6] was reported to be superior to their respective

unreinforced alloys. A large number of experiments were done independently on the Al / SiCp [4 – 6] and Al /

Graphite [3, 7]. The outer lubricant traditionally plays an important role in wear behaviour. Al alloy wear behavior

strengthened with SiCp-Graphite particles has not been newly understood. As a result, the present study used a

mixture of high-hardened SiC particles and soft graphite to examine the wear actions of the Al alloy reinforced with

SiC particles and graphite. It was observed that wear test volume losses of Al – Mg – Cu alloy continuously

decrease to 5%. It has also been found that silicon carbide particles play a significant role in improving the Al – Mg

– Cu alloying system's wear resistance. All Al – Mg – Cu alloys and Al – Mg – Cu / SiC composites were found to

Orig

inal A

rticle International Journal of Mechanical and Production

Engineering Research and Development (IJMPERD)

ISSN (P): 2249–6890; ISSN (E): 2249–8001

Vol. 10, Issue 3, Jun 2020, 10339-10350

© TJPR Pvt. Ltd.

http://www.tjprc.org/

10340 B. N. V. Srinivas, K. Dorathi, Dr. N. Tulasi Radha, G. Ramaprasad

Impact Factor (JCC): 8.8746 SCOPUS Indexed Journal NAAS Rating: 3.11

form mechanically mixed layer (MML) due to the move of Fe from counter face disk to plate [8]. In their analysis on the

sliding wear of in situ composites Al–4Cu – TiB2, Mandal et al[9] reported that TiB2 particles greatly improved the wear

efficiency of the alloy Al–4Cu. The reaction mixture of K2TiF6 and KBF4 with molten alloy prepared a low-cost system

of Al 6063 xTiB2 (x = 0, 5, 10 wt. per cent) in situ metal matrix composites (MMCs). Such composites prepared in situ

were characterized by the use of scanning electron microscope, X-ray diffractometer and study of micro hardness. The

prepared composite’s dry sliding wear behavior was investigated using a Pin on Disc method at different applied loads of

9.8, 19.6 and 29.4 N for different temperatures (100, 200 and 300 C). The findings show that with the change in the weight

percentage of TiB2 the wear rate decreases, although it increases with the rise in the load added [10]. Roy et al. [11]

compared aluminum wear resistance reinforced with TiC, TiB2, B4C, SiC powder metallurgy route synthesized. TiB2 had

been reported to show better wear resistance than other dispersoids. However, limited work has been reported on the wear

and friction behavior of these composites at high temperatures [12–22]. Jianxin et al. [12] reported Al2O3–TiB2 / SiC

composites wear conduct at a temperature of up to 800 C. It has been emphasized that at higher temperatures oxidative

wear was regulated. Oxidation of the materials plays a significant role in sliding contact of materials under conditions

when the operating temperature is high, causing changes in overall wear rate. Several researchers have established the

value of oxidation during wear of metallic materials and a classification of moderate and extreme wear was suggested

based on contact resistance assessment, wear debris analysis and microscopic inspection. Quinn et al.[13] and Lim and

Ashby[14] extensively discussed the role of the oxide scale for ambient temperature wear. Many investigators have also

studied the impact of applied load on the wear rate of Al-based composite prepared by other routes [22–33]. It was stressed

that the rate of wear increases with the load applied.

2. EXPERIMENTATION

Preparation of Composite

Stir casting is a two – step mixing process. In this process, the matrix material is heated to above its liquid temperature so

that the metal is totally melted. The melt is then cooled down to a temperature between the liquids and solidus points and

kept in a semi solid state. At this stage, the preheated particles are added and mixed. The slurry is again heated to a fully

liquid state and mixed thoroughly. This two – step mixing process has been used in the fabrication of aluminium. Among

all the well – established metal matrix composite fabrication methods, stir casting is the most economical. For that reason,

stir casting is currently the most popular commercial method of producing aluminium based composites.

Figure 1: SEM Image of Al 6063

Wear Behaviour of Aluminium Metal Matrix Composites Reinforced with Copper and Graphite 10341


Muffle furnace is used as a pre heated furnace for the matrix materials copper and graphite which is heated at

4000c for 1 hour.. The powder samples are indicated below.

Figure 2: Copper and Graphite Powders

The copper and graphite powder samples are taken into a bowl and mixed. The mixed powder is placed in muffle

furnace for pre-heating purpose. This is done in order to remove moisture content because the presence of moisture content

might result in formation of air gaps in the final mould.

Stir Casting Procedure

The experimental setup consist of an assembled coupling gear box motor and mild steel four blade stirrer. The melting of

the aluminium (Al6063) pieces and copper, graphite powder are carried out in a graphite crucible. The capacity of the

crucible is 1kg. First the pieces of aluminium in their respective composition are placed in the furnace by keeping them in a

crucible. The temperature of the furnace is set to reach 7000c because the melting point of aluminium is 6500c and this is

done to compensate losses during stirring and other heat losses. The rising temperature of the furnace is checked from time

to time. Copper and graphite powders are taken in a bowl and mixed thoroughly and placed in a muffle furnace for pre-

heating. The pre-heating ensure elimination of moisture content so that the mould obtained does not have any air gaps.

During the melting of aluminium there is formation of film above the molten metal. The film formed is removed by using a

cast iron rod and the process is made to progress. After the temperature reaches 7000c the furnace door is opened, the

power supply is switched off and the pre-heated copper and graphite mixture is poured carefully into the crucible.

Figure 3: Stir Casting Equipment Setup

The mixture is now thoroughly stirred by using the stirrer which is operated by a motor and rotates at 200rpm. the

stirring process is carried out for 10 minutes. Now the furnace power supply is again switched on because the molten metal

losses heat during the stirring process. So the process is again carried out until the furnace reaches 8000c. the temperature is




now being raised to 8000c because the re-crystallization temperatures of graphite and copper are higher than that of

aluminium. The actual melting points of copper and graphite are 10830c and 35000c respectively. But the temperature is

only maintained at 8000c because only minute quantities of copper gets mixed up. The main aim of the project is to

continue the properties of aluminium and also imparting strength and conductivity properties by adding copper and

graphite. So only lesser weight quantities of copper and graphite are added because higher quantities may affect the

properties of aluminium. Now as the temperature reaches 8000c the crucible is taken out and the molten metal mould is

poured into the die carefully. The pouring should be continuous or otherwise there will be formation of air gaps and also

uneven distribution of the molten metal in the die takes place which may lead to cracks or even breakage of the material

after solidification of the material. Three composites were fabricated by taking copperas 4% and graphite is taken as 2%,

4%, 6% and according to that aluminium is arranged. The total composition is taken as 750 grams and as per that weight

percentages were calculated and weighed by using weighing machine. In this way, stir casting setup is used for all the three

compositions as stated above.

The die is now kept in air for half an hour. During this time the mould solidifies. The mould is now taken out by

removing the bolts of the die and removed carefully. The obtained mould is separated into pieces and then machined for

better finish. Now the machined piece again cut into different cross-section required for the different tests to be conducted

on them. The mould cavity is used to make the molten metal into a desired shape and size based on our requirements. The

permanent die made up of cast iron. The depth of the cavity is 100mm and the diameter is 15mm.

The matrix composite mixture is poured into the mould. The die is fixed by nut and bolt arrangement. After that

the metal matrix samples are formed and it is cut into required sizes.

Figure 4: MMC Specimens

The formed samples are cut into required sizes by using abrasive cutting machine and then they are taken for

different tests.

The final obtained metal matrix samples are of diameter about 15mm and 100mm in length.

3. RESULTS AND DISCUSSION

Experimental Wear Tests

Pin-on - disk monitoring is used to determine the slipping wear behaviour. The simple wear test equipment design is shown

in Fig. This consists of a screw connected to a spinning disc. The test piece of concern can be either the pin or the tape. The

pin's touch surface can be spherical, or square. Such tests have been performed in compliance with ASTM G99, which



requires the use of a rounded pin, but does not define precise values for the parameters, and thus these are chosen by the

users to match the method.

This is lightweight equipment designed specifically for testing wear under sliding pressure. Typically, slipping is

between a fixed pin and a spinning disk. The disk rotates with the help of a D. C. Motor; has a frequency of 0–2000rpm

with a wear track diameter of 20–150 mm, and may achieve sliding speeds of 0 to 30m / sec. Load is to be placed by dead

weight arrangement on pin (specimen). The machine has a maximum 1000N loading capacity. The substrate / coated

samples used the cylindrical pins (10 mm diameter and 25 mm height) as test material. The polished chromium steel disk

(100Cr6) was used as the coating on the counter side. The wear checks were conducted at 50N, sliding speed held at

600rpm. Wear tests were carried out with no lubrication at room temperature (30–36°C). Weight of the specimens before

and after the experiment was taken. This test was done before and after ageing. After ageing, cooling was also done in two

ways such as Air cooled and water cooled.

Figure 5: Wear Test Samples

Figure 6: Wear Test Machine




Figure 7: Graph of Al 4%Cu2%Gr – Before Ageing

Figure 8: Graph of Al 4%Cu2%Gr – After Ageing (air cooled)

Figure 9: Graph of Al 4%Cu2%Gr – After Ageing (water cooled)




Figure 11: Graph of Al 4%Cu4%Gr – After Ageing (Air Cooled)

Figure 12: Graph of Al 4%Cu4%Gr – After Ageing (Water Cooled)





Figure 14: Graph of Al 4%Cu6%Gr – After Ageing (Air Cooled)

Figure 15: Graph of Al 4%Cu4%Gr – After Ageing (Water Cooled)



Table 1: Wear of Materials with Varying Ageing and Cooling

% of Samples Before Ageing

(gms)

After Ageing(gms)

Air Cooled Water Cooled

Al4%Cu2%Gr 0.33 0.05 0.25

Al4%Cu4%Gr 0.77 0.56 0.02

Al4%Cu6%Gr 0.59 0.25 0.1

Figure 16: Graph of Wear of Various Samples

Wear behaviour of Al4%Cu4%Gr was studied and analyzed using the SEM images. From the above graph, we

can observe that the wear rate increases with the increase of both frictional force and time. But by observing, frictional

force vs time, we can clearly say that, as the time increases the frictional force is constant and decreases and again remains

constant.




Figure 17: SEM Images of the Worn Surfaces of Al4Cu4Gr a) Before Ageing b) After Ageing (Air Cooled) c) After

Ageing (Water Cooled)

4. CONCLUSIONS

Al4Cu4Gr4 has shown a typical trend during the ageing and the cooling process.

Al 92% Cu 4% Gr4% i.e 0.02 grams (after ageing and water cooled) has less wear rate.

REFERNCES

1. Ibrahim, I. A., Mohamed, F. A., Lavernia, E. J. Metal Matrix Composites. A Review Journal of Material Science 26 1991: pp.

1137 – 1157.

2. Sinclair, I., Gregson, P. J. Structural Performance of Discontinuous Metal Matrix Composites Material Science and

Technology 3 1997: pp. 709 – 725.

3. REDDY, A. CHENNAKEESAVA. "Low and High Temperature Micromechanical Behavior of BN/3003 Aluminum Alloy

Nanocomposites." International Journal of Mechanical Engineering and Technology 6.4 (2017): 27-34.

4. Hsiao Yeh Chu, Jen Fin Lin. Experimental Analysis of the Tribological Behavior of Electroless Nickel-Coated Graphite

Particles in Aluminum Matrix Composites under Reciprocating Motion Wear 239 2000: pp. 126 – 142.

5. Lim, S. C., Gupta, M., Ren, L., Kwok, J. K. M. The Tribological Properties of Al-Cu/SiCp Metal Matrix Composites Fabricated

using the Rheocasting Technique Journal of Materials Processing Technology 89 – 90 1999: pp. 591 – 596.

6. Park, B. G., Crosky, A. G., Hellier, A. K. Material Characterization and Mechanical Properties of Al2O3-Al Metal Matrix

Composites Journal of Material Science 36 2001: pp. 2417 – 2426.

7. Grigoris Kiourtsidis, E., Stefanos Skolianos, M. Wear Behaviour of Artificially Aged AA2024/40µm SiCp Composites in

Comparison with Conventionally Wear Resistance Ferrous Materials Wear 253 2002: pp. 946 – 956.

8. Mohan, S., Pathak, J. P., Gupta, R. C., Srivastava, S. Wear Behavior of Graphitic Aluminium Composite Sliding under Dry



Conditions Wear 93 2002: pp. 1245 – 1251.

9. Adel M, HassanA, AlrashdanM, T. Hayajneh A, TurkiM, Wear behavior of Al–Mg–Cu–based composites containing SiC

particles, Tribology International, 42 2009: pp 1230-1238.

10. Mandal A, Chakraborty M, Murty BS. Effect of TiB2 particles on sliding wear behaviour of Al–4Cu alloy. Wear 2007;262: pp

160–166.

11. S. Natarajan, R. Narayanasamy, S. P. Kumaresh Babu, G. Dinesh, B. Anil Kumar, K. Sivaprasad, Sliding wear behaviour of Al

6063/TiB2 in situ composites at elevated temperatures, Materials and Design 30 (2009) 2521–2531

12. Roy M, Venkataraman B, Bhanuprasad VV, Mahajan YR, Sundararajan G. The effect of particulate reinforcement on the

sliding wear behaviour of aluminium matrix composites. Metall Mater Trans A 1992;23:2833–47.

13. Deng Jianxin. Friction and wear behaviour of Al2O3/TiB2/SiC ceramic composites at temperatures up to 800 C. Ceram Int

2001;27:135–41.

14. Quinn TFJ, Sullivan JL, Rowson DM. Origins and development of oxidational wear at low ambient temperatures. Wear

1984;94:175–91.

15. Lim SC, Ashby MF. Overview no. 55 wear-mechanism maps. Acta Metall 1987;35:1–24.

16. Singh J, Alpas AT. Elevated temperature wear of Al6061 and A16061–20%Al2O3. Scripta Metall Mater 1995;32:1099–105.

17. Stott FH. High-temperature sliding wear of metals. Tribol Int 2002;35:489–95.

18. Omar, ADEL A., M. El-Shennawy, and M. Ayad. "Study of Wear Behavior of as Cast TiC/7075 Composite." International

Journal of Mechanical Engineering 4.4 (2015): 45-52.

19. Degnan CC, Shipway PH, Wood JV. Elevated temperature sliding wear behaviour of TiC-reinforced steel matrix composites.

Wear 2001;251:1444–51.

20. Liu Yao-hui, Du Juna, Yu Si-rong, Wang Wei. High temperature friction and wear behaviour of Al2O3 and/or carbon short

fibre reinforced Al–12Si alloy composites. Wear 2004;256:275–85.

21. Muratoglu M, Aksoy M. The effects of temperature on wear behaviours of Al– Cu alloy and Al–Cu:SiC composite. Mater Sci

Eng A 2000;282:91–9.

22. Pauschitz, Manish Roy, Franek F. Mechanisms of sliding wear of metals and alloys at elevated temperatures. Tribiol Int

2007;41:584–602.

23. Hans Berns, Stefan Koch. High temperature sliding abrasion of a nickel-base alloy and composite. Wear 1999;225–229:154–

62.

24. Xie Z-H, Hoffman M, Moon RJ, Munroe PR, Cheng YB. Sliding wear behaviour of Ca–Sialon ceramics at 600 C in air. Wear

2006;260:1356–60.

25. Basavarajappa S, Chandramohan G, Subramanian R, Chandrasekar. Dry sliding wear behaviour of Al 2219/SiC metal matrix

composites. Mater Sci Pol 2006;24. No. 2/1.

26. Ferhat Gul, Mehmet Acilar. Effect of the reinforcement volume fraction on the dry sliding wear behaviour of Al–10Si/SiC

composites produced by vacuum infiltration technique. Compos Sci Technol 2004;64:1959–70.

27. Andrew Emgea, Karthikeyan S, Kima HJ, Rigney DA. The effect of sliding velocity on the tribological behavior of copper.

Wear 2007;263:614–8.

28. Saduman Sen, Ugur Sen. Sliding wear behavior of niobium carbide coated AISI 1040 steel. Wear 2008;264:219–25.

29. Saber, D., Kh Abd El-Aziz, and A. Fathy. "Corrosion behavior of copper–alumina nanocomposites in different corrosive

media." Int. J. Mech. Eng 5 (2016): 1-10.

30. Tjong SC, Lau KC. Sliding wear of stainless steel matrix composite reinforced with TiB2 particles. Mater Lett 1999;41:153–8.

31. Abachi P, Masoudi A, Purazrang K. Dry sliding wear behavior of SiC/QE22 magnesium alloy matrix composites. Mater Sci

Eng A 2006;435–436: 653–7.

32. Rajan, S. Thanga Kasi, et al. "Compression and corrosion behaviour of sintered copper-fly ash composite material." Materials

Research Express 6.4 (2019): 046524.


https://www.sciencedirect.com/science/article/pii/S0301679X09000796#!






33. Daoud MT, Abou El-Khair, Abdel-Azim AN. Effect of Al2O3 particles on the microstructure and sliding wear of 7075 Al alloy

manufactured by squeeze casting method. ASM Int 2004;13:135–43.

34. Jianxin D, Xing A. Friction and wear behavior of Al2O3/TiB2 composite against cemented carbide in various atmospheres at

elevated temperature. Wear 1996;195:128–32.

35. Jianxin D, Xing A. SiC whisker reinforced Al2O3/TiB2 ceramic composites. Chin Ceram Soc 1995;23(4):385–92.

36. Jianxin D, Xing A. Ceramic composites. J Chin Soc Corros Prot 1997;17(2):276–83.

37. Mandal R, Maiti M, Chakraborty, Murty BS. Effect of TiB2 particles on aging response of Al–4Cu alloy. Mater Sci Eng A

2004;386:296–300.

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