Effect of sliding speed on tribological behaviour of heat treated hypoeutectic Al-7Si alloy and hybrid metal matrix composites

In the present paper, effect of sliding speed on wear behaviour of as-cast and heat treated hypoeutectic Al-7Si alloy and hybrid metal matrix composites have been investigated. Aluminium is used as matrix and Silicon Carbide (SiC) and graphite (Gr) particles are used as reinforcements. The proposed Aluminium Metal Matrix Composites (AMMCs) was fabricated by stir-cast method. Aluminium A356 matrix and reinforcements of SiCp was varied from 0 to 9% by weights in steps of 3%, and addition of fixed quantity of 3% by weight of Gr particles. The castings were machined as per ASTM standard and T6-heat-treatment was carried out. Specimens were aged at different durations from 3 to 12 hrs in steps of 3 hrs at a temperature of 155 ºC. The pin-on-disc wear testing machine was employed to evaluate the wear rate of the composites. As per the results, addition of reinforcement and aged at T6-9 hrs shows most wear resistance in all sliding tests. The increase in sliding speed with increase of wear rate was observed. The wear tested samples were examined using scanning electron microscope (SEM) and energy dispersive spectrum (EDS) and analysed.