Structural characterization of {101¯2} twin boundaries in cobalt

Abstract

Using high-resolution transmission electron microscopy, we characterized the structures of {101¯2} deformation twin boundaries (TBs) in cobalt and found that TBs consist of {101¯2} coherent twinning boundaries and basal-prismatic interfaces (BPs or PBs). According to these structural features, the propagation of {101¯2} twins cannot be simply accomplished through the glide-shuffle mechanism of twinning dislocations. Correspondingly, two migration mechanisms of such TBs are proposed based on dislocation theory. In addition, abundant basal stacking faults are observed experimentally to connect with TBs, and this phenomenon is ascribed to the release of residual dislocations resulting from the migration of the BPs and PBs.