Effect of ageing time on mechanical properties and tribological behaviour of aluminium hybrid composite

Aluminium/alumina/graphite hybrid metal matrix composites prepared by using the stir casting technique were heat treated to enhance mechanical properties such as strength, hardness and wear resistance. The present study evaluates the effect of ageing time on the hardness, tensile strength and tribological behaviour of both unreinforced Al-Si10Mg alloy and aluminium hybrid metal matrix composites. Results for composite samples were compared with those of as-cast samples. Results showed that heat treated samples of alloy and composite showed higher hardness, tensile strength and tribological properties compared to both as-cast alloy and composite. Among the different ageing times employed, specimens aged for 4 hours showed maximum mechanical and tribological properties. Investigations of the worn surfaces were carried out using scanning electron microscopy to understand the wear mechanism.