Formation of adiabatic shear band within Ti-6Al-4V: An in-situ study with high-speed photography and temperature measurement

Shear failure is frequently accompanied by the formation of an adiabatic shear band (ASB) under dynamic loading conditions. It was widely believed that both the thermal softening and stress state exert great influence on the initiation of the ASB. However, clear knowledge regarding the true mechanisms is still lacking and experimental research is especially needed. In this paper, a novel in-situ experimental setup was developed to observe the deformation localization and temperature evolution of the ASB simultaneously, by using the high-speed photography and high-speed infrared radiation (IR). The effect of the temperature increase on the initiation of the ASB was studied with the modified shear-compression specimens (SCS) of three different degrees. It is found that before the initiation of the ASB, the temperature of the deformed region in the SCS does not increase rapidly. Then, intense increment of temperature was found with the initiation and propagation of the ASB. The typical events—including the peak stress, the initiation of the ASB, and the maximum temperature—for adiabatic shear failure are ordered chronologically. It is proved that temperature increase may not the primary factor that triggers the initiation of the ASB.