Shock wave-induced multiple deformation modes in a HfNbZrVTi high-entropy alloy

The deformation behaviors in HfNbZrVTi high-entropy alloy (HEA) under shock loading are investigated. We find that, in addition to dislocation slip, multiple deformation modes are activated, including {112} kink banding, {112}<111> deformation twinning, and body-centered cubic (BCC) to omega phase transition. Atomic-scale characterization of deformation interfaces reveals that pressure dependent kink banding is driven by the movement of a₀/2<111>{112} edge dislocation pairs, while the BCC to omega phase transition involves atomic shuffling of 1/12[111¯] and 1/12[1¯1¯1] on adjacent (21¯1)_BCC planes. Furthermore, the omega phase distributes at the twin boundary accompanied with the formation of transient omega phase. These findings reflect unique deformation behaviors of HEAs comprising mixed multiple elements in extreme loading conditions.