Grain-boundary migration was demonstrated to proceed by lateral propagation of a small step in a (113)[110] symmetrical Al tilt grain-boundary. In situ high-resolution transmission electron microscopy at 523K allowed the study of atomic-scale detail at video rates during the migration process. The grain-boundary translational states on both sides of the step were identical, which leads to a step dislocation. This defect could move laterally by a combination of climb and glide. Dynamic high-resolution transmission electron microscopic images indicated considerable atomic agitation within the dislocation core. A detailed temporal analysis of the step movements revealed small random displacements of the dislocation core.

High-Resolution Electron Microscopy at a (113) Symmetric Thermally Activated Step Motion Observed by Tilt Grain-Boundary in Aluminium. K.L.Merkle, L.J.Thompson, F.Phillipp: Philosophical Magazine Letters, 2002, 82[11], 589-97