Abstract
<jats:p>The growing demand for lightweight and high-performance materials in engineering applications has led to the extensive development of aluminium-based hybrid metal matrix composites (HMMCs). In the present investigation, AA6061 aluminium alloy was selected as the matrix material and reinforced with a combination of Pista Shell Ash (PSA), an agrowaste material, and Silicon Carbide (SiC), a ceramic reinforcement, in varying weight percentages. The composites were fabricated using the friction stir casting technique to ensure uniform distribution of reinforcement particles and improved interfacial bonding. Four different compositions were prepared, namely unreinforced AA6061, and hybrid composites containing 1% PSA + 1% SiC, 2% PSA + 2% SiC, and 3% PSA + 3% SiC. Mechanical properties such as hardness, toughness, and compressive strength were evaluated to assess the influence of reinforcement addition. The results revealed a progressive increase in hardness and compressive strength with increasing reinforcement content, with maximum improvements of 19% and 23% respectively observed for the highest reinforcement composition. However, a reduction in toughness was observed, indicating increased brittleness due to the presence of hard ceramic phases. The study demonstrates that PSA can be effectively utilized as a sustainable reinforcement material in hybrid composites, enhancing mechanical performance while contributing to waste valorization.</jats:p>