Behavior of Ti-6Al-4V alloy at high strain rates, shear testing up to 6 x 10^E4 1/s and failure criterion

Abstract
Plastic behavior in shear of Ti-alloy : Ti-6Al-4V is the theme of this paper. A fast hydraulic machine, and the direct impact technique with impact velocities from 2 m/s to 120 m/s were applied to study this alloy. The following range of strain rate was applied : l0^E-3 to 5* 10^E4 1/s using the MDS specimen geometry, [2]. The role of the stress concentrator is discussed in triggering of failure by Adiabatic Shear Bands (ASB). A local failure criterion is proposed which is based on the critical strain of the final localization. The criterion has been applied in a numerical code, [10], permitting to calculate dynamic failure by adiabatic shearing. Finally, a brief discussion is includes on the Critical Impact Velocity in shear, [1,2,7,10].