Characterization of shock-induced anomalous {11(2)over-bar1} twinning activity in a beta-cooled zirconium

摘要

In this work, quasi-static compression and shock loading experiments were performed on a beta-cooled commercial pure zirconium at room temperature to investigate the corresponding twinning behaviors, utilizing electron channeling contrast (ECC) imaging and electron backscatter diffraction (EBSD) technique. Results show that twins are introduced under both deformation conditions, while their fractions are quite different. The high strain rate during shock loadings facilitates the activation of twins, leading to a much larger fraction of deformation twins. Distinct from previous work, we report anomalous parallel {11 (2) over bar1} (1)over bar>(1) over bar 26> twinning activities in the shock loading sample but not in the quasi-static compression one, implying that the facilitating effect of strain rate on such twinning mode might be more obvious in the present work. Based on Schmid factor calculation, the special grain orientations obtained by beta slow cooling, together with the poor strain accommodation capacity due to suppressing prismatic slips, are responsible for the dense {11 (2) over bar1} < <(1)over bar>(1) over bar 26> twins under shock loadings.