Influence of Hybrid Ceramic Reinforcements on Wear Response Features of Al-7068 Metal Matrix Composites

This paper explores the tribological research of hybrid composites that have been developed by reinforcing Al7068 aluminum alloy with Silicon Carbide (SiC) and Silicon Nitride (Si3N4). The reinforcement levels of the micro-sized particles were varied to form a uniform distribution of the reinforcements within the Al7068 matrix by the stir casting technique. Silicon Carbide (SiC) was incorporated at 0--1% by weight, and Silicon Nitride ( Si3N4) was added at 0--2.5% by weight. The material's tribology and hardness were measured using a pin-on-disc apparatus and a Rockwell hardness tester. The presence of Si3N4 improved the overall wear behaviour of the composite by reducing crack propagation, while SiC contributed to increased hardness and wear resistance. FESEM and optical microscopic investigations revealed significant variations in dendritic structures and reinforcement dispersion across different compositions from S1 to S5.