Fracture toughness of cast and extruded Al6061/15%Al2O3p metal matrix composites

Particulate reinforced metal matrix composites (PRMMCs) are of interest owing to the low cost of their raw materials and their ease of fabrication, making them suitable for applications requiring relatively high-volume production. The improved properties of PRMMCs result from the addition of hard ceramic particles (such as Al2O3 or SiC); the size, shape, volume fraction, interfacial properties and distribution of these (together with the fabrication method) determine the mechanical behaviour of the composite. However, PRMMCs have inferior ductility, toughness and low-cycle fatigue properties compared with unreinforced alloys, often limiting their usefulness in practice. Reinforcements of between 15 volume % and 25 volume % (but most commonly 20 volume %) have found commercial application, as these are considered to provide the optimal combination of structural properties.