Detection of particle damage event by acoustic emission during tensile straining of SiC particle reinforced aluminium alloy composites

The fracture mechanisms of composites which contain coarse second phase (30 µmSiC) have been studied by acoustic emissions measurement. The fracture mechanism for these composites is different from that for composites containing small particles. In the latter case, it is well known that the void nucleation during fracture occurs at interface between matrix and reinforcement. The experimental data and the current model for fracture were compared, and fracture strain has been estimated using a modified particle fracture model based on the Evensen void growth model. Acoustic emissions were detected from fractured particle, although there are some differences in AE responses caused by difference in heat treatment. Void nucleation occurs by particle fracture in all of the materials. A modified equation for the fracture strain has been proposed and this equation provides a good quantitative agreement with experimental data.