Post shock mechanical behavior of fcc and bcc metals: Application to copper and tantalum

Abstract
In the first part of this paper, the mechanical characterization carried out on pure copper and tantalum grades are presented. The analysis of these data puts in evidence the activation of thermally activated mechanisms within a large range of temperature and strain rate. In a second part of the paper, shock recovery tests are reported. The range of shock pressure is 10 GPa - 40 GPa. Based on the comparison between the as received and post shock copper and tantalum viscoplastic behaviors, we show that shock wave effects are related to strain rate history effects and/or microstructural modifications. The activation of the different deformation mechanisms can be related to the shock pressure level and the typical material crystallographic structure (bcc, fcc).