Statistical optimization and cryogenic treatment effects on the wear behavior of stir-cast Al-SiC-Gr hybrid composites

Abstract Aluminum matrix composites are increasingly used in automotive and aerospace applications due to their superior strength-to-weight ratio and wear resistance; however, improving their tribological performance remains a key challenge. This study numerically investigates the wear behavior of Al6061–SiC–Gr hybrid composites fabricated by the stir casting method. The matrix alloy Al6061 was reinforced with 13 wt% Silicon Carbide (SiC) and Graphite (Gr) at 1, 2, and 3 wt% levels. Taguchi’s L16 orthogonal array was employed to design experiments considering reinforcement percentage, cryogenic treatment duration (0, 24, 36, and 48 h), load (10–40 N), sliding speed (600–1200 rpm), and sliding time (5–20 min) as factors. Wear scar depth and coefficient of friction were analyzed as responses. Results showed that the Al–13%SiC–2%Gr composite exhibited the best wear resistance with the lowest wear scar depth and coefficient of friction. A 36 h cryogenic treatment further enhanced performance through microstructural refinement and phase stabilization. Fractography confirmed uniform reinforcement dispersion and the lubricating effect of graphite. The study concludes that combining hybrid reinforcement with optimized cryogenic treatment significantly improves wear performance of aluminum composites. It is recommended for applications requiring high wear resistance, and the findings imply potential for extending component life in tribological systems.