Dry sliding wear behaviour of aluminium/alumina/graphite hybrid metal matrix composites

Purpose - Recent trends in material science show a considerable interest in the manufacturing of metal matrix composites to meet the stringent demands of lightweight, high strength and corrosion resistance. Aluminium is the popular matrix metal currently in vogue that can be reinforced with ceramic materials such as particulates to meet the desired property. The purpose of this paper is to fabricate hybrid metal matrix composites to improve the dry sliding wear resistance and to study of the effect of sliding speed, load and reinforcement (alumina and graphite) on wear properties, as well as its contact friction. Design/methodology/approach - The present study addresses the dry sliding wear behaviour of Al-Si10Mg alloy reinforced with 3, 6 and 9 wt% of alumina along with 3 wt% of graphite. Stir casting method was used to fabricate the composites. Mechanical properties such as hardness and tensile strength have been evaluated. A pin-on-disc wear test apparatus was used to evaluate the wear rate and coefficient of friction by varying the loads of 20, 30 and 40 N, sliding speeds of 1.5 m/s, 2.5 m/s and 3.5 m/s at a constant sliding distance of 2100 m. Findings - Mechanical properties of hybrid metal matrix composites (HMMCs) have shown significant improvement. The wear rate and coefficient of friction for alloy and composites decreased with increase in sliding speed and increased with increase in applied load. Temperature rise during wearing process for monolithic alloy was larger than that of HMMCs and Al/9% Al2O3/3% Gr composite showing the minimum temperature rise.The worn surfaces of the composites were investigated using scanning electron microscope. Practical implications - The paper shows that aluminium composites can improve strength and wear resistance. Originality/value - HMMCs has proven to be useful in improving the dry sliding wear resistance.