Predicting Texture Evolution in Ta and Ta-10W Alloys Using Polycrystal Plasticity

Abstract

We present results of texture characterization and predictions of a multiscale physically based constitutive law developed to predict the mechanical response and texture evolution of body-centered cubic metals. The model is unique in the sense that single crystal deformation results not only from the resolved shear stress along the direction of slip (Schmid law) but also from shear stresses resolved along directions orthogonal to the slip direction as well as the three normal stress components (non-Schmid effects). The single crystal model is implemented into a visco-plastic self-consistent homogenization scheme containing a hardening law for crystallographic slip. The polycrystal model is calibrated using a set of mechanical test data collected on a tantalum-tungsten alloy, Ta-10W, in tension and compression and pure tantalum, Ta, in tension, compression, and cross-rolling. We demonstrate that the model effectively captures the texture evolution in all cases. We show that alloying has the effect of increasing the dislocation friction stress, the trapping rate of dislocations, and activation barrier for recovery.