On the mechanism of shear-coupled grain boundary migration in FCC crystals

One of the possible mechanisms of metal plasticity is shear-coupled migration of grain boundaries under applied mechanical stress. Several different approaches to the description of shear-coupled migration of grain boundaries and to the prediction of the coupling factor exist in the literature. Some of them are based on the solution of Frank–Bilby equation and consideration of grain boundary (GB) dislocation content; other is based on consideration of disconnection glide along the GB. The first approach describes the boundary as an array of dislocations; the second one considers the glide of disconnection along a dislocation-free boundary. Despite the existence of opinions that these approaches are incompatible, we demonstrate internal interrelation between them by consideration of shear-coupled migration of Σ3(111) boundary in face-centred cubic copper. It is demonstrated that there is no contradiction between approaches and their combination can help to understand the physical mechanisms of shear-coupled boundary migration.