Grain boundary and triple junction migration

The current status and latest achievements of grain boundary (GB) and triple junction (TJ) migration in metals are reviewed. The migration of 90 degrees [112] planar tilt symmetrical and asymmetrical GB in specially grown Bi-bicrystals driven by magnetic force and the dependence of GB mobility on temperature, driving force and the direction of motion are addressed. The motion of low-and high angle planar tilt [112] and [111] GBs moved by shear stresses and the peculiarities of such a motion are considered. In particular, the sharp transition from low- to high-angle boundaries was observed. In practice the motion of a straight GB is the exception rather than the rule. The shape of a moving GB is a source of new and useful findings concerning GB migration. The experimentally derived shape of a GB in Al-bicrystals was compared with theoretical calculations in the Lucke-Detert approximation. The experimental and theoretical results of a motion of grain boundary systems with triple junctions are presented. Their impact on the kinetics of microstructure evolution and, in particular, on Von Neumann-Mullins relation is outlined. (C) 2001 Elsevier Science B.V. All rights reserved.