Molecular dynamics simulations of grain boundary migration of a bcc metal, tungsten, were carried out. The grain boundary was of asymmetrical <110> tilt type. Detailed examinations of atomic processes in the migration, showed that the grain boundary migration consisted mainly of grain boundary dislocation glide. Furthermore, each motion of a grain boundary dislocation involved a cooperative motion of about 3 atoms on each of the atomic planes perpendicular to the tilt axis, leading to their realignment from the receding grain to the advancing grain. This collective motion was not synchronized in all of the atomic planes, but appeared to be in two or three adjacent planes, suggesting a kink mechanism for glides of the grain boundary dislocations.

Collective Motion of Atoms in Grain Boundary Migration of a BCC Metal. L.Zhou, N.Zhou, G.Song: Philosophical Magazine, 2006, 86[36], 5885-95