Thermomechanical behavior of single crystalline tantalum in the static and dynamic regime

This paper reports the thermomechanical behavior of single crystalline tantalum (Ta) in the [1 0 0] and [1 1 0] orientations. Mechanical testing was carried out at low and high strain rates using a Kolsky bar together with the simultaneous recording of the specimen's temperature by means of an infrared detector. The results show a marked difference in terms of flow curve and strain hardening between the two orientations, irrespective of the strain-rate. Similarly, the thermomechanical behavior, namely the efficiency of the thermomechanical conversion at high strain-rates (beta(int)), is observed to be different for each orientation. A comparison of the present results with those obtained for pure polycrystalline Ta (Rittel et aL, 2007) reveals some similarity of flow curves with the [1 0 0] orientation. By contrast, the [1 1 0] orientation is observed to possess beta(int) characteristics that are similar to those of the polycrystalline material. These results are presented and discussed, thus completing the overall experimental characterization of this material in order to enable the simulation and validation of the dynamic behavior of polycrystalline Ta on the basis of its single-crystal characteristics. (C) 2009 Elsevier Ltd. All rights reserved.