Planar shock compression of single crystal tantalum from 6-23 GPa

Planar impact experiments have been performed to produce simultaneous shock loading of the three principal orientations of single crystal tantalum ([100], [110] and [111]) to peak stresses of 6 and 23 GPa. Results reveal that the [100] orientation exhibits the largest elastic limit. Shock velocity measurements indicate that for all of the materials, and most notably in the [100] orientation, there is a low stress excursion from a linear U-s-u(p) plot similar to that previously seen in polycrystalline tantalum. This suggests sensitivities at low stress which require further investigation. The experiments have been simulated using a single crystal plasticity finite element model that accounts for thermally-activated and drag-resisted dislocation motion, and for evolution of the dislocation density. The model is seen to qualitatively describe some of the features described above.