Influence of ageing temperature on the tribological characteristics of LM25/Al₂O₃/SiC hybrid metal matrix composite for lightweight applications

The demand for hybrid composites has lately increased due to their extraordinary qualities, which include unique mechanical, tribological, and physical capabilities not found in other materials. These composites improve performance and utility by mixing different reinforcing components, making them highly sought after. However, there is a study gap on the effects of long-term ageing on the tribological characteristics of LM25 (Al-6.6Si-0.2Mg)/Al2O3/SiC metal matrix composites (MMCs). As a result, extensive studies on the influence of ageing temperature on the tribological properties of LM25/Al2O3/SiC MMCs via long-term ageing effects still need to be included. Therefore, this study investigated the metallurgical and hardness properties of stir-cast LM25 alloy reinforced with Al2O3 and SiC particulates with varying ageing temperatures. Furthermore, dry sliding wear behaviour is also examined. The investigation concluded that adding micron-sized Al2O3 and SiC particles to LM25 improves hardness and tribological properties. As the ageing temperature increased, the eutectic particles became coarser. Furthermore, the result illustrates that the coefficient of friction (COF) values also enhanced with wear rates. Higher loads increased the wear rate and COF, whereas higher sliding speeds decreased the COF and wear rate.