Disconnection-mediated motion of ⟨110⟩ tilt grain boundaries in a-Fe

Abstract

It is possible for ⟨110⟩ tilt grain boundaries (GBs) in bcc metals to perform a conservative displacement by the glide of intrinsic GB line defects, namely, disconnections. The paper presents the characteristic of these defects in {112} and {332} twin boundaries, their vicinal GBs, and the {116} GB studied by molecular dynamics simulation. The sources of disconnections and their interaction with the other GB dislocations are described together with their role in the shear-coupled GB migration. The absence of gliding disconnections in the {111} GB impedes the shear-coupled GB migration, but two pure shuffles inside the coincident site lattice unit facilitate the transformation of the {111} GB into {110}/{001} or {110}/{112} facets in regions of concentration of stresses.