The influence of texture, strain rate, temperature, and chemistry on the mechanical behavior of hafnium

The compressive mechanical behavior of highly textured, polycrystalline hafnium has been examined as a function of texture, strain rate, temperature, and material chemistry. The microstructural and substructural evolution in Hf was also examined as a function of texture. Decreasing temperature, increasing strain rate, and increasing impurity concentrations were found to increase the yield-stress and work-hardening rates, as well as increase the amount of twinning in Hf. Crystallographic texture was found to exhibit the most marked effect on the mechanical behavior of Hf. Differences in the orientation of the c-axis with respect to the loading direction were found to affect the yield stress, work-hardening behavior, and anisotropy of the tested specimen, with the highest yield stresses and rates of work hardening and the lowest anisotropies in specimens compressed along the c-axis. The amount of deformation twinning and the slip systems activated during deformation were seen to vary based on texture and are shown to correlate well with the observed yield stresses and work-hardening behaviors.