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

The effects of electric pulse heat (EPH) treatment on microstructures and mechanical properties of hot-rolled equiaxed TC4 alloy were investigated. Results show that the original equiaxed microstructure of hot-rolled TC4 alloy turns into the typical lamellar microstructure through EPH within 5 min, and the time microstructure transformation needs becomes shorter with the increasing heat treatment temperature. Recrystallization happens in the equiaxed microstructure before microstructure transformation; after microstructure transformation, the prior beta grains grow with higher temperature and longer holding time. The results of quasi-static and dynamic compression tests indicate that the fracture strain value of alloys after EPH treatment is significantly improved, which decreases with the increasing temperature and holding time, while the susceptibility to the adiabatic shear bands (ASBs) of the hot-rolled TC4 titanium alloy is obviously decreased. Compared with the original hot-rolled titanium alloy, the adiabatic shear fracture strain of the alloy after EPH treatment at 1000℃ for 5 min is increased by 133%, and the energy absorbed by materials before adiabatic shear failure is increased by 192%.