Effect of applied pressure on high-stress abrasive wear behavior of hybrid Al–Mg–Si composites

In this experimental investigation, the effect of applied pressure on high-stress abrasive wear resistance characteristics of stir-cast Al 6082-5 wt% SiC-5 wt%Gr (Al–SiC–Gr) hybrid metal matrix composites was studied and compared with its unreinforced matrix alloy and 10 wt% SiC-reinforced (Al–SiC) composites. The tests were carried on pin-on-disc equipment at applied pressures of 0.1–0.3 MPa, sliding distance of 75 m, and SiC abrasive grit size of 100 µm and 200 µm. It was noted that the wear resistance decreases with increase in applied pressure in both as-cast and T6 conditions. The improvement in wear resistance was 1.63 (alloy) to 3.29 m/mm³ (Al–SiC–Gr) in case of lower grit size and applied pressures. However, the marginal improvement of wear resistance was observed i.e. 0.67 (alloy) to 1.05 m/mm³ (Al–SiC–Gr) at higher grit size and applied pressures. Relative wear resistance plots indicate that hybrid composites conceded better wear resistance properties compared to SiC-reinforced composites. The evaluation of wear mechanisms, worn surfaces of the pins, emery papers, and debris was also studied using scanning electron microscopy.