Mechanical behaviour of stir cast aluminum matrix composites reinforced with silicon carbide and palm kernel shell ash

Microstructural analysis and mechanical behaviour of aluminum matrix composites (AMCs) reinforced with palm kernel shell ash (PKSA) and silicon carbide (SiC) were studied. The AMCs containing 6, 8, 10 and 12 wt.% reinforcements, with weight ratios of 0:1, 1:3, 1:1, 3:1 and 1:0 (PKSA: SiC) were produced using stir casting method. % Porosity, hardness, tensile strength (UTS), ductility and fracture toughness were determined following standard procedures, while Scanning electron microscopy (SEM-EDS) was used for structural characterization. The results show that the composites produced have improved hardness. The UTS improved with increase in PKSA attaining maximum value at reinforcement weight ratio 1:1 and then decreases, the 6 wt.% reinforcement being the only exception. The ductility of the composites was lower than the unreinforced aluminum alloy with the SiC single-reinforced having the lowest. Also Fracture toughness was observed to be less than the unreinforced aluminum alloy with the SiC single reinforced having the lowest value. The PSKA:SiC weight ratio 1:1 gave the best property combination with optimum properties in terms of UTS (175.48MPa), ductility (8.61) and fracture toughness [6.5MPa(m)1/2].