Effects of prior ECAP process on the dynamic impact behaviors of hypereutectic Al-Si alloy

The dynamic mechanical responses of as-cast and ECAPed hypereutectic Al-Si alloy subjected to high strain rate compression by split Hopkinson pressure bar (SHPB) system were investigated. The result shows that the dynamic yield strength of the investigated alloy first decreases with the first ECAP pass, followed by an increase in strength with further increase in ECAP passes. Increasing the number of ECAP passes also results in the refinement of both grains and deleterious crack-nucleating particles and in turn, results in the decrease in susceptibility to thermo-mechanical instability and formation of adiabatic shear bands (ASBs). The activation of dynamic recovery (DRV) and dynamic recrystallization (DRX) by increasing the number of ECAP passes were found to significantly suppress dynamic mechanical damage.