Microstructural characterization of SiC/Al and FP/Al metal matrix composites subjected to dynamic loadings

The Split Hopkinson Pressure Bar technique was used to study the dynamic response of silicon carbide particle- and whisker-reinforced aluminium (SiC/Al-P and SiC/Al-W) and continuous Fibre FP-reinforced aluminium (FP/Al), metal matrix composites, subjected to high strain rates in the range of 300–3200 s^–1. The response of these composites was characterized by macroscopic and microscopic observations. Experiments on SiC/Al-W and FP/Al were conducted with the whiskers/fibres oriented in the axial, as well as, in the transverse direction with respect to the loading direction. It was observed that for the silicon carbide-reinforced metal matrix composites, the dynamic flow stress values were consistently higher than the static/quasi-static values. Experiments conducted on FP/Al with the fibres oriented transversely to the loading direction, revealed failure stress values considerably lower than the static/quasi-static values. This anomalous behaviour was attributed to the predominantly shear mode failure of the material. Microscopic observations using optical and scanning electron microscopy corroborate the macroscopically observed behaviour.