Slip-Driven B 1 − B 2 Phase Transition in Shock-Compressed KCl

The mechanisms, pathways, and driving force for the classical B1-B2 transitions have long been elusive. Here, we conduct ultrafast x-ray diffraction measurements and systematic atomistic simulations of single-crystal KCl under shock compression and establish a unified model for the B1-B2 transition in KCl. The transition proceeds via resolved-shear-stress-driven slip through two generalized transition pathways, yielding two generalized B1-B2 orientation relationships. Resolved-shear-stress-driven slip is potentially a common mechanism for general B1-B2 transitions.