Modelling single crystal tantalum across a dynamic range of strain rates with a new crystal plasticity model

Tantalum is a body-centered cubic (BCC) material used in a number of applications that undergo high strain rates and temperatures. In the design of such applications, it is important to understand the material's behavior as it transitions to these extreme conditions. Recent sets of single crystal high strain rate and quasi-static experiments have been conducted on tantalum which have challenged traditional crystal plasticity models. We will first present here a new crystal plasticity model. Then we will show how three different experimental platforms at very different strain rates allow us to parameterize different aspects of the model. Additionally, we will examine how different modelling assumptions affect the quasi-static single crystal response. Finally, we will show the predictive capabilities of the optimized material set against a series of hole closure type experiments. This work is performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DEAC52-07NA27344 (LLNL-ABS- 845082).