The migration of <110> tilt boundaries in bicrystals was investigated as a function of the misorientation angle, driving force and temperature. Two regions of differing migration behavior were observed. A change in mobility occurred as the driving force decreased. In the higher driving force region, the activation energy for grain boundary migration was equal to about 2/3 of the energy for Fe bulk self-diffusion. This indicated that the boundary motion might be governed by grain boundary diffusion. In the lower driving force region, the activation energy for migration increased to about 220kJ/mol. This value agreed well with the activation energy for the intrinsic diffusion of Si in -Fe. This suggested that the grain boundary was dragging a Si atmosphere. Moreover, the rate of boundary migration was found to depend upon the misorientation. Thus, the mobility of coincidence boundaries (especially  = 9) was higher than that of random boundaries.

S.Tsurekawa, T.Ueda, K.Ichikawa, H.Nakashima, Y.Yoshitomi, H.Yoshinaga: Materials Science Forum, 1996, 204-206, 221-6