Optimizing the Tribological Performance of Copper-Reinforced A356 Aluminum Alloy: Influence of Heat Treatment and Composition Variation

Recent progress in metal matrix composites (MMCs) has led to significant research efforts aimed at refining reinforcement methods and processing techniques and enhancing material properties. Incorporating reinforcements has notably improved both mechanical strength and tribological performance while addressing issues such as porosity and particle agglomeration. This study investigates the impact of copper reinforcement (1–4 wt.%) on the tribological characteristics of A356 alloy under both as-cast and heat-treated conditions. The process of heat treatment involved age hardening, where the composites were solution heat treated (SHT) at 535 °C for 2 h, followed by rapid quenching and aging at 100 °C and 200 °C. The results demonstrate that increasing the copper content enhances the composite’s mechanical properties. Specifically, heat treatment promoted the redistribution of the Al₂Cu intermetallic phase during peak aging, leading to improved hardness and wear resistance. Wear testing demonstrated that heat-treated composites exhibited significantly better wear resistance than their as-cast counterparts, with improvements of 50–60% under lower loads and 80–90% under higher loads. Among the tested samples, A356 alloy reinforced with 4 wt.% copper showed the lowest wear rate across all the applied loads, along with a reduced coefficient of friction and enhanced load-bearing capacity, minimizing material deformation. Additionally, aging at 100 °C resulted in the greatest hardness and the lowest wear rate in comparison to untreated A356 alloy. These findings underscore the viability of copper-reinforced A356 composites for applications demanding enhanced mechanical characteristics and wear resistance.