Viscoplastic deformations and compressive damage in an A359/SiC_p metal-matrix composite

Recent work by the authors has examined the high-strain-rate compression of a metal-matrix composite consisting of an A359 Al alloy matrix reinforced by 20 vol.% of silicon carbide particulates (SiC_p). The work-hardening that is observed in the experiments is much lower than that predicted by analytical and computational models which assume perfect particle-matrix interfaces and undamaged particles. In this work, we show that the discrepancy is a result of particle damage that develops within the A359/SiC_p composite under compression. The evolution of particle damage has been characterized using quantitative microscopy, and is shown to be a function of the applied strain. A simple analytical model that incorporates evolving damage within the composite is proposed, and it is shown that the analytical predictions are consistent with the experimental observations over a wide range of strain rates.