Fracture behaviour of 2D-weaved, silica-silica continuous fibre-reinforced, ceramic-matrix composites (CFCCs)

摘要

Significantly improved fracture resistance (in terms of fracture toughness and fracture energy) can be imparted to monolithic ceramics by adopting composite design methodology based on fibre reinforcement technology. The present paper describes the fracture behaviour of one such fibre-reinforced material, namely the silica-silica based continuous fibre-reinforced, ceramic-matrix composite (CFCC) in two orthogonal notch orientations of crack divider and crack arrester orientations. Different fracture resistance parameters have been evaluated to provide a quantitative treatment of the observed fracture behaviour. From this study, it has been concluded that the overall fracture resistance of the CFCC is best reflected by total fracture energy release rate (J_C), which parameter encompasses most of the fracture events/processes. The J_c values of the composite are found to be more than an order of magnitude higher than the energy values corresponding to the plane strain fracture toughness (J_(KQ), derived from K_(IC), the plane strain fracture toughness) and >200 percent higher than elastic-plastic fracture toughness (J_(IC)). Apart from this, the composite is found to exhibit high degree of anisotropy in the fracture resistance and also, a significant variation in the relative degree of shear component with crack extension.v