Prismatic dislocation- {11-21} twin interaction as a source of uncommon pyramidal-〈a〉 dislocation in HCP metals

The interaction between prismatic dislocations and a {112¯1} twin boundary is systematically investigated using atomistic simulations. Interestingly, when the slip plane is parallel to the plane of shear, the parent prismatic dislocation is transmuted into a prismatic dislocation in the twin while the Burgers vector remains unchanged. In contrast, when the prismatic slip plane is inclined with the plane of shear, the prismatic dislocation is transmuted into the uncommon pyramidal-⟨a⟩ dislocation on the {101¯1} plane. The energetics during twin-slip interactions are quantified by Nudged Elastic Band calculations. Our results provide a new understanding in terms of twin-slip interaction in HCP metals. We reveal a novel formation mechanism for the uncommon pyramidal-⟨a⟩ dislocation via twin-slip interactions and quantify the associated energy barrier, advancing our understanding of twin-slip interactions in HCP metals.