The Effect of Ceramic Reinforcement on the Microstructure, Mechanical Properties and Tribological Behavior of Al-7.5%Si-0.5%Mg Alloy

Abstract:

In this investigation, A357 (Al-7.5%Si-0.5%Mg) alloy/Al₂O₃ composites with various weight fractions (4%, 8%, 10%) were prepared by using permanent mould casting. In addition, A357 alloys were cast for comparison purposes. Microstructure, hardness and tensile properties of these composites were evaluated and compared with as-cast alloy. In addition, tribological properties of these composites were evaluated using a Pin-on-Disc apparatus at a constant sliding velocity of 1m/s and pressure of 0.35 MPa. The microstructure of the composites shows homogenous distribution of Al₂O₃ plate-like particles in the Al matrix except in the A357/10%Al₂O₃ composite. The wear and mechanical properties of composites improve with increasing the weight percentage of Al₂O₃ upto 8% and then decreases. Particularly, mechanical properties of the A357/10%Al₂O₃ composite are lower than the alloy indicating that the critical weight fraction of Al₂O₃ reinforcement in the A357 alloy is 8%. Wear morphology studies show that higher wear rate in case of unreinforced specimen was associated with higher thickness of hardened layer and consequent delamination of wear debris from the surface which was confirmed by optical and scanning electron micrography.Whereas ductile and brittle mode of fracture is observed in Fractographic observation of composite. The present paper highlights the salient features of casting technique and characterization of aluminum alloy A357 and alumina metal matrix composite.

• Periodical: Applied Mechanics and Materials (Volume 867)
• Pages: 3-9
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.867.3
• Online since: July 2017
• Authors: L. Avinash*, Hemanth Kumar, Adithya Parthasarathy, K.N. Varun Kumar, Basavaraj Sajjan
• Keywords: Permanent Mould Casting, Reinforcement, Sliding Velocity, Tribology

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