A scanning probe microscopic study was made of grain boundary migration in Ni-rich material at 1400C. The migration of grain boundaries during annealing was quantified by using scanning probe microscopic measurements of the surface topography of the regions which had been swept through by migrating grain boundaries. It was shown that quantitative conclusions concerning the dynamics of grain boundary motion could be drawn from a study of the surface topography in the vicinity of individual migrated boundaries and of migrated triple junctions. In the case of the individual boundaries, the curvature of the blunted root of the grain-boundary groove which formed at the original boundary position provided information on the start of the migration process. In the case of triple junctions that moved along one of the 3 boundaries forming the junction, the variable width of the grain-boundary groove reflected the dynamics of the migration process. By using the Mullins model for grain-boundary grooving, and its modifications, it was estimated that the grain boundary migration rate was 0.52μm/s. This was much higher than the average migration rate which was deduced by dividing the migration distance by the total annealing time. It was concluded that, in the near-surface region, the grain boundaries migrated in a jerky intermittent fashion.

Scanning Probe Microscopy Study of Grain Boundary Migration in NiAl. E.Rabkin, Y.Amouyal, L.Klinger: Acta Materialia, 2004, 52[17], 4953-9