Microstructure and twinning behavior of b.c.c tantalum under dynamic plastic deformation

Abstract

In this paper, dynamic plastic deformation (DPD) of tantalum (Ta) was achieved by split Hopkinson pressure bar and a variety of DPD conditions were set to systematically investigate the microstructure of the deformed samples, focusing on the twinning behavior. Results showed that the deformation conditions have a significant effect on the number and distribution of {112}<111>twins. Compared with {100} and {111} grains, {110} grains are more prone to twinning due to the fewer slip systems. As the strain rate increases or the deformation temperature decreases, the number of twins increases dramatically. In addition, the texture of Ta samples gradually changes from {110} to mixed {100} and {111} textures with the increasing deformation, and the number of twins first increases and then decreases. After calculation, it is found that the selection of twin variants in Ta under DPD not only follows Schmid law but is also influenced by strain coordination. The research in this paper deepens the understanding of tantalum as a material for armour-piercing projectile.