The motion of planar symmetrical <100> tilt boundaries in high-purity material was investigated in situ under the influence of an external mechanical stress field. It was observed that the motion of planar <100> tilt boundaries could be activated by an applied shear stress which acted perpendicularly to the grain boundary plane. The motion of the grain boundaries was thermally activated, and the activation parameters for motion could be derived from in situ data on the mobility at various temperatures. A sharp transition between low-angle grain boundaries and high-angle grain boundaries was observed, at 8.6°, for planar tilt boundaries. This was apparent from a step change in the activation enthalpy for stress-induced grain boundary motion. The observed activation parameters for stress-induced motion could be related to the activation parameters for self-diffusion, for the motion of low-angle boundaries, and to the activation parameters for grain-boundary diffusion, for the motion of high-angle grain boundaries. From these correlations, it was concluded that the motion of planar low- and high-angle grain boundaries, under the influence of a mechanical stress field, could be attributed to the movement of the grain-boundary dislocations which made up the structure of the boundary.

Motion of <100>-Tilt Grain Boundaries. M.Winning: Acta Materialia, 2003, 51[20], 6465-75