Effects of Secondary α Phase Width on Dynamic Mechanical Properties and Sensitivity of Adiabatic Shear Banding in Bimodal Microstructures of TC4 Alloy

Dynamic mechanical properties and sensitivity of adiabatic shear banding of TC4 alloy with bimodal microstructures were investigated using Split Hopkinson Bar. The bimodal microstructures with different-width secondary α phase (α_s) were obtained via different heat treatment. The results show that the width of α_s increases with the decreasing of cooling rate. In dynamic compression experiments, the dynamic strength decreases as the width of α_s increases; while the dynamic strain exhibits an opposite trend. In forced shearing experiments, the sensitivity of adiabatic shear banding decreases as the width of α_s increases. Besides, the sensitivity of adiabatic shear banding increases for the same microstructure with the increasing of impact velocity.