Fracture analysis of the transition zone between unreinforced alloy and composite

The transition zone between unreinforced alloy and composite is an important problem for selectively reinforced metal-matrix composites manufactured by the squeeze casting technique, mainly because of the weakness of this zone. Developing an understanding of transition zone behaviour is therefore essential. The main purpose of this research was to evaluate the influence of ageing time on the fracture behaviour of such a zone for Saffil (γ-alumina) A356 aluminium alloy composites. Tensile tests were carried out and the fracture surfaces were analysed to evaluate the fracture behaviour. Analysis of microstructure and fracture surfaces was performed using optical and scanning electron microscopies.