Effects of electric pulse heat treatment on mechanical properties and adiabatic shear banding of hot-rolled lamellar TC4 alloy

The effects of electric pulse heat treatment performed by SPS equipment on mechanical properties and the susceptibility to adiabatic shear bands of hot-rolled lamellar TC4 alloy were studied. The results show that electric pulse heat treatment has little effect on the strength and ductility of TC4 alloy at the static compression loading, and it also has little effect on the yielding strength at the dynamic compression loading, but the heat treatment has evident effects on the susceptibility to adiabatic shear bands of the hot-rolled TC4. After electric pulse heat treatment at 900℃, TC4 alloy exhibits the highest adiabatic shear failure strain under the dynamic compression loading and the highest energy absorption of unit volume before fracture. Compared with the hot-rolled TC4 alloy, the adiabatic shear failure strain of heat-treated TC4 increases by 57% and the energy absorption of unit volume increases by 42%, indicating that the susceptibility to adiabatic shear bands of TC4 significantly decreases. The microstructure analysis results reveal that the electric pulse heat treatment has obvious influences on the original β grain size and the detailed microstructure characteristics of TC4 alloy. After the heat treatment at 900℃, the original β grain size decreases remarkably, while the transformed β colony size increases, but the width of α plate shows no change.