Dynamic crystal plasticity modeling of single crystal tantalum and validation using Taylor cylinder impact tests

We have significantly extended a previous dislocation-density based constitutive theory to enable modeling the strong influence of temperature and strain rate on the thermomechanical behavior of single crystal body centered cubic (BCC) tantalum. The extension include an expression of saturation dislocation density as a function of instantaneous strain rate and temperature and a dynamic recovery fraction that effectively saturates the immobile dislocation density. Crystallographic slip along <111> on the {110} or {112} planes as well as their combination are examined. The model is calibrated using a Bayesian approach against experimental measurements include uniaxial stress-strain curves obtained from quasi-static and split Hopkinson pressure bar (SHPB) compression tests in a wide range of strain rate and temperature, and velocity-time histories from single crystal flyer plate impact experiments. The calibrated model was applied to simulate previous Taylor cylinder impact experiments. The comparison of deformed Taylor cylinder shapes between the simulation and experiments sheds light on activated slip systems in single crystal tantalum.