| The behavior of tantalum single crystals when compressed with the loading axis parallel to <125> has been studied at three temperatures (198K, 298K, and 373K), two strain rates (10-4s-1 and 1s-1), and two strain histories (as-grown and pre-strained). Out of plane displacements were measured using a two surface in situ interferometer and strain rosettes were used to record axial and transverse surface strains. These methods of collecting data allowed the detailed observation of micro-yield and the influence of the loading geometry on the deformation. An analysis of the limits of strain gauge measurements of crystals oriented for single slip supported the experimental data. A finite element analysis of the loading geometry indicated the stress distribution was not uniform. Relaxation tests revealed the rate sensitivity of both the pre-yield and work hardening behavior. |
