Interaction of migrating grain boundaries with crystal defects : observation by in situ SR topography

The study of migration of well-characterized grain boundaries (GBs) in bicrystals of an Fe-Si alloy by in situ synchrotron radiation (SR) topography is described. The differences in migration behaviour of the (100)/(110) asymmetrical tilt GB and {hk0} symmetrical tilt GB in the 45° [001] bicrystal at 1293 K are evidently connected with intersections of the GB with low angle subgrain boundaries or changes of the circular shape of migrating GB to a straight one (faceting on low-index GB planes). From reliable data the product of GB mobility and energy was determined which is comparable with that obtained previously by optical measurements after annealing experiments.