WEAR AND MECHANICAL PROPERTIES OF ALUMINIUM HYBRID COMPOSITE (AL2024/AL 2 O 3 /GRAPHITE) FABRICATED BY POWDER METALLURGY

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1 Volume 116 No , ISSN: (printed version); ISSN: (on-line version) url: ijpam.eu WEAR AND MECHANICAL PROPERTIES OF ALUMINIUM HYBRID COMPOSITE (AL2024/AL 2 O 3 /GRAPHITE) FABRICATED BY POWDER METALLURGY 1 Aatthisugan, 2 Razal Rose A, 3 Iruthayaraj R; 4 Palani S, 5 Shanmugan S 1,2 Department of Mechanical Engineering, SRM University, Kattankulathur, Chennai. 3,4 Department of Mechanical Engineering, Vel Tech Multitech, Avadi, Chennai Department of Physics, Vel Tech Multitech, Vel Tech Multitech, Avadi, Chennai aatthisugan@gmail.com; 2 razalrose.a@ktr.srmuniv.ac.in 3 iruthayaraj@veltechmultitech.org; 4 spalani@veltechmultitech.org 5 s.shanmugam1982@gmail.com Abstract: In this paper, it is aimed to present the experimental results of the studies tribological properties of aluminium hybrid composites. The dry sliding wear test is carried out for sliding speeds at 1 m/s, normal loads up to 30N and sliding distance up to 3000m using a pin on disc apparatus. It is found that the addition of Al 2 O 3 and graphite reinforcements increases the wear resistance of the composites. The wear loss increases with the increase in load and sliding distance same as the coefficient of friction. The microphotographs of the hybrid composites studied revealed the uniform distribution of the particles in the matrix system. As compared with pure Al2024, the density and porosity values of Al2024 hybrid composite were decreased and hardness values slightly increased. Key Words: Aluminum-based composite, powder metallurgy, microstructure, wear, friction. 1. Introduction The application of powder metallurgy process is economically feasible only for high mass production and parts made by powder metallurgy process exhibit properties, which cannot be produced by conventional methods. Simple shaped parts can be made to size with high precision without waste, and completely or almost ready for installation [1]. Among the MMCs, Aluminium MMCs are smarter because of their low density, high specific stiffness and specific strength, as well as arrogant wear resistance [2]. Ceramic particles such as SiC and Al 2 O 3 are the most widely used materials for reinforcement of aluminium [3]. The convince of sliding speed on the dry sliding wear performance and subsurface warp of hybrid metal matrix composites by a liquid metallurgy technique [4]. The development of a tribolayer deferred the transition from mild wears to severe. In powder metallurgy process, the Aluminium MMCs are made-up from powders without fleeting through a completely melting condition. Also, P/M technique can achieve a further consistent circulation of particulates in the metal matrix not including or with less extreme reactions between the matrix and reinforcement [5]. The combination of graphite and its exceptional properties are more significant for a wide range of applications in erosive, abrasive, corrosive or high-temperature environments. Through the past years, huge quantities of methods have been working for the production of MMCs. Among these methods, powder metallurgy (P/M) procedure provides a number of rewards for making composites. It requires the low built-up temperature and can gain the equivalence in the reinforcement distribution [6]. In the current effort, the major aim is to study the possibility of the production of Al 2 O ceramic particulate and graphite solid lubricant reinforced aluminium MMCs by P/M technique. An attempt is made to in sort to build up a more inexpensive and easy process for aluminium matrix composite production Materials 2. Experimental setup and procedures The details of elemental metal powders used in this study to make Al 2024 (matrix alloy) are presented in Table 1. The powders used for the fabrication of composite in this study were: aluminum powder with an average particle size of 40µm (commercial D grade Al, 99% purity), copper powder with an average particle size of 30µm and magnesium powder with an average particle size of 60µm as a matrix and silicon carbide powder purity that exceeds 99.5% with an average particle size of 50µm and flake Graphite powder with an average particle size of 55µm. Table 2 provides the specifics of the Al 2 O 3 and graphite particulates, which were worn as reinforcements. Powder mixtures with calculated concerto of wt % Al 2 O 3 and graphite be varied by ball milling for 6 h, and were cold pushed uniaxially into cylindrical preforms (18mm diameter and 25mm height) at pressures of ranging from 250 MPa. The green 231

2 preforms were heated to 510 C in a furnace, kept 1 hr for soaking. Table 1. Chemical composition of the matrix alloy % Al Fe Mn Cu Mg Cr Si Al max 0.15 min max 0.05 max Table 2. Details of reinforcements Sample No. Al2024 (%) Al 2 O 3 (%) Gr (%) Density measurement By the rule of mixtures theoretical density was calculated [7]. The exact densities for the uncontaminated Al2024 and composite are calculated using Archimedes principle. The cylindrical section be weighed in air (W a ), then balanced in distilled water and weighed another time (W w ). The actual density was projected according to Eq. (1). ρ a = W a / (W a - W w ) x ρ w (1) ρ a = Actual Density ρ w = Density of water The section is to be weighed by a photoelectric balance among an accuracy of 0.1mg Wear testing Dry sliding wear tests are performing by pin-on-disc equipment (Ducom, model No: ED-201, Bangalore, India). The contradict disc substance was of EN31 steel. Earlier to test, the pins and disc face be cleaned by acetone. All the test were carried out using hybrid composites pins of various compositions with an applied load of 5 to 30N,sliding speed of 1m/s for a varying sliding distance of 500 to 3000m. Following every test, the sample and counter face disk is cleaned by organic solvents to eliminate traces. The pin is weighed ahead of and after testing to an accuracy of 0.1 mg to conclude the quantity of wear loss. Each test was repeated three times and results were averaged. 3. Results and discussion 3.1 Density and hardness measurement Table 3 shows the theoretical density and Brinell hardness (BHN) of the samples. It can be concluded that the densities of composites are higher than that of their base alloy. Further the density of the composite increases with increase in percentage of reinforcement content in the composite. The results of hardness measurement of composites show that the decrease in the size of the particle increases the strength of the composite. The reinforcement hard materials are responsible for increase in strength and hardness of the composite. Hardness was measured in Brinell hardness machine at 500kgf load and the steel ball of diameter 2.5mm was used as indenter. Table 3. Mechanical properties of samples Material Hardness Density (g/cm3) Type (BHN) Sample Sample Sample Microstructure analysis The optical microstructures of the specimens were shown in Fig. 1. Before analysis the specimen, were wet ground using abrasive paper (400, 600, 1000 & 1200 grit, respectively). Then the specimen was polished using diamond paste. Fig. 1(a) shows microstructure of pure aluminium alloy Fig. 1(b) shows the microstructure of aluminium alloy added 10 wt% Al 2 O 3 particles. It is observed that particles the uniformly distributed. Fig. 1 (c) shows the further adding 5wt% of graphite particles Al- Al 2 O 3 composite. The even circulation improves the mechanical and tribological properties of the composites. 232

3 Figure 1. Microstructure analysis (a) Al2024, (b) Al- Al 2 O 3, (c) Al- Al 2 O 3 -Gr 3.3. Wear loss and coefficient of friction Effect of load Fig. 2 shows the variation of wear loss with applied load and Fig. 3 shows the variation of coefficient of friction with applied load. The tests have been carried out by taken a constant applied load of 15 N and constant sliding velocity of 1m/s. It is observed that an increase in load results in increased wear loss and coefficient of friction for the samples. However, Al Al 2 O 3 possesses the lower wear loss when compared with base alloy at all the loads studied. In this study it is observed that the composite Al/ Al 2 O 3 /Gr were lowest wear loss compare to other composites and base alloy, because of solid lubricant graphite. Figure 2. Variation of wear loss against load 233

4 Figure 3. Variation of Coefficient of friction against load Effect of sliding distance Fig. 4 shows the variation of wear loss of Al2024, Al Al 2 O 3, Al/Al 2 O 3 /Gr hybrid composites with varying sliding distance. It is observed that, the wear loss increases drastically up to a sliding distance of 500m. With further increase in sliding distance there is a steady increase in the wear loss. The enhancement in wear loss in the initial period can be ascribed to the higher loss of material due to running condition during which a perfect contact between the pin and the disc will be made. It is clearly observed that the base alloy materials have higher wear loss compare to the composite. Fig. 5 shows the variation of co-efficient of friction against sliding distance. The tests have been carried out by taken a constant applied load of 15 N and constant sliding velocity of 1m/s. It is observed that with increased load the coefficient of friction increase gradually up to a sliding distance 3000m. For the both the base alloy and composites, the coefficient friction increases with increase in sliding distance because the increase sliding distance. Figure 4. Variation of co-efficient of friction against sliding distance 234

5 Figure 5. Variation of co-efficient of friction against sliding distance 4. Conclusion In the current study, the aluminium matrix hybrid composite was successfully fabricated by the powder metallurgy process. The hardness, wear test and micro structural study of the hybrid composite were evaluated. The obtained density and hardness results can be summarized as mentioned above. The hybrid composite displays higher hardness compared with the base material, which is attributed to the presence of hard Al 2 O 3. Furthermore, the decrease in hardness for the hybrid composite when compared to Al/ Al 2 O composite may be due to the presence of Gr particles. The incorporation of Al 2 O 3 reinforcement to Aluminium matrix increases the wear resistance of the composites. The addition graphite reinforcement in Al/Al 2 O 3 composite as hybrid reinforcement further increases the wear resistance of the composite. References [1] Rajender singh. Introduction to basic manufacturing processes and workshop technology. New Age International (P) Ltd., Publishers, (2006). [2] Suresha S, Sridhara BK. Effect of addition of graphite particulates on the wear behaviour in aluminium silicon carbide graphite composites. Mater Des (2010); 31: [3] Kaczmar JW, Pietrzak K, Wlosinski W. The production and application of metal matrix composite materials. J Mater Process Technol (2000); 106: [4] Basavarajappa S, Chandramohan G, Mukund K, Ashwin M, Prabu M. Dry sliding wear behaviour of Al2219/SiCp Gr hybrid metal matrix composites. J Mater Eng Perform (2006); 15: [5] Riahi AR, Alpas AT. The role of tribo-layers on the sliding wear behaviour of graphitic aluminum matrix composites. Wear (2001); 251: [6] P. Ravindran, K. Manisekar, P. Narayanasamy, N. Selvakumar, R. Narayanasamy, Application of factorial techniques to study the wear of Al hybrid composites with graphite addition. Materials and Design 39 (2012) [7] M. Merola, Mater. Sci. Eng., A Struct. Mater: Prop. Microstruct. Process. 214 (1996) [8] T.Padmapriya and V.Saminadan, Utility based Vertical Handoff Decision Model for LTE-A networks, International Journal of Computer Science and Information Security, ISSN , vol.14, no.11, November [9] T. Padmapriya and V. Saminadan, Priority based fair resource allocation and Admission Control Technique for Multi-user Multi-class downlink Traffic in LTE-Advanced Networks, International Journal of Advanced Research, vol.5, no.1, pp , January [10] S.V.Manikanthan and V.Rama Optimal Performance Of Key Predistribution Protocol In Wireless Sensor Networks International Innovative Research Journal of Engineering and Technology,ISSN NO: ,Vol-2,Issue Special March [11] S.V.Manikanthan and T.Padmapriya Recent Trends In M2m Communications In 4g Networks And Evolution Towards 5g International Journal of Pure and Applied Mathematics, ISSN NO: , Vol- 115, Issue -8, Sep

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