EFFECTS OF INTERFACE DEBONDING ON THE TOUGHNESS OF DUCTILE PARTICLE REINFORCED CERAMICS

A debonding-stretching model is proposed in this work to analyse the effects of interfacial debonding on the ductile particle toughening of ceramics. Perfect bonding imposes lateral constraints on the particles thus prohibiting the full utilization of the particle's inherent ductility. In contrast, partial debonding increases the plastic stretching which leads to a larger crack opening displacement in the bridging zone. The theoretical prediction of the fracture toughness based on the debondingstretching model is closer to that measured by experiments. A continuous model based on the micromechanical analysis of the plastically stretched particles is used to calculate the deformation field in the bridging zone for a Mode I plane strain crack loaded under small scale bridging condition. The length of the bridging zone is determined numerically as a function of the applied stress intensity factor and relevant material parameters. © 1990.