Effect of Heat Treatment on Sliding Wear Resistance of Hybrid Aluminum Matrix Composite

Abstract

Composite materials with aluminum as matrix material have a wider amplitude of large-scale applications in engineering. Some salient features of aluminum matrix composites are, low density, low thermal coefficient of performance and low weight and high strength. Among the various series of aluminum alloy, Al6061 have been widely used by researchers due to its outstanding properties particularly as they are heat treatable. Aluminum 6061 alloys have been reinforced with various particulate reinforcements such as silicon carbide, and graphite to study their friction and wear resistance properties. Adding silicon carbide particulate reinforcement improves the sliding wear resistance of composite material. However, it makes the material brittle and hard resulting in machining difficulties and rough surface finish. On the other hand, it has been found from the literature survey that the addition of graphite particulate reinforcement increases ductility and sliding wear resistance. In this context, the present article focuses on developing hybrid aluminum matrix composites by incorporating both graphite and silicon carbide. Heat treatment has been carried out to further enhance the wear resistance and strength of the composites. Vortex-stir casting was successfully utilized to fabricate Al6061-SiC-Gr hybrid composites. There was excellent bonding between the matrix and reinforcement materials as revealed by the microstructure study. The sliding wear resistance of the Al6061-SiC composite was higher than the base matrix material. Heat treatment increases the sliding wear resistance of the composite. Ice quenching results in maximum improvement. Increased content of graphite increases the sliding wear resistance of Al6061-SiC composite. Further heat treatment increases the sliding wear resistance of the hybrid composites with ice quenching resulting in maximum improvement.