High strain-rate strength response of single crystal Tantalum through in-situ hole closure imaging experiments

The properties of crystalline materials often depend on directionality and operating conditions. Specifically, the strength of materials can depend anisotropically on crystal direction and the loading condition. To probe these effects, a preliminary series of high strain-rate (>10⁵/s) strength plate-impact hole closure experiments were performed on high purity single crystal Tantalum cubes. The impact/loading condition and orientation of the single crystals with respect to loading were varied to provide data to inform crystal plasticity modeling efforts. The experiments consist of in-situ high-resolution X-ray radiographic imaging of the hole collapse under dynamic compression conditions to infer the material strength via its resistance to closure at ever increasing levels of plastic strain. The experiments are compared against hydrocode simulation predictions. The samples are recovered and characterized with EBSD to evaluate the deformation structure that developed during the extreme loading.