Microstructure-based modelling of fracture of particulate reinforced metal matrix composites

Abstract

This paper aims to develop a microstructure-based model to describe the material deformation and fracture of the particulate reinforced metal matrix composites. The A359/SiC composite was used as a material example. The most important factors, such as particle morphology, distribution and fracture, matrix deformation and failure, and particle-matrix debonding, were comprehensively integrated into the modelling. Relevant experiments were also conducted. It was found that such a microstructure-based model can capture the major material deformation and failure mechanisms. The particle geometry and distribution can be described by normalized shape factor and clustering distance. Stress concentrations occur at the clustered particles, especially at the sharp corners, particle-matrix interfaces and the edges along the loading direction. The stress in the matrix is much lower than that in the particles and concentrates along 45° to the loading direction. Matrix-particle debonding is not noticeable. Particle fracture happens near its sharp corners, while matrix failure initiates around the particle crack tips and propagates to connect the microcracks caused by particle fracture, or through the area with high stress/strain concentration, leading to the fracture of the whole workpiece.