Effects of Volume Fraction of Transformed β Matrix on Dynamic Mechanical Properties and Sensitivity of Adiabatic Shear Banding in Bimodal Microstructures of TC4 Alloy

The 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 volume fractions of transformed β matrix were obtained via different heat treatments. Results show that the volume fraction of transformed β matrix increases with the increasing of solution temperature. In dynamic compression experiments, the dynamic strength rises at first and decreases later as the volume fraction of transformed β matrix increases, and reaches its maximum value when the volume fraction of transformed β matrix is 80.7%. While the dynamic strain decreases with the increasing of volume fraction of transformed β matrix. In forced shearing experiments, the sensitivity of adiabatic shear banding decreases at first and increases later as the volume fraction of transformed β matrix increases, and reaches its minimum value when the volume fraction of transformed β matrix is 80.7%. Besides, the sensitivity of adiabatic shear banding increases for the same microstructure with the increasing of impact velocity.