Fracture mechanics behaviour of aluminium matrix composites reinforced with SiC

Low fracture toughness in metal matrix composites is one of the main obstacles to using these materials in widespread ways and, therefore, various aspects of fracture mode would be examined closely, pointing out the microstructure influence. In the present paper, fracture nucleation and propagation of two aluminium matrix composites having about 30 vol.% SiC as reinforcement were studied. Tensile tests and fracture toughness tests were executed and the effect of reinforcement particle size and distribution was considered. The effect of T4 treatment (solution treating at 495°C for 2 h, quenching in water at 10°C and natural ageing three weeks long) was also evaluated in terms of mechanical properties and fracture mechanism.