The impact of faceting on the high-angle grain boundary motion was studied. The non-steady-state motion of the 57° [11•0] tilt grain boundary half-loop in a Zn bicrystal was studied in situ. Above 678K the slowly migrating grain boundary half-loop was continuously curved. Below this temperature, the moving grain boundary was fully or partially faceted. The transformation of a curved grain boundary into a grain boundary facet with increasing temperature was observed for the first time. Overlapping faceting/roughening of three crystallograpically different grain boundary facets led to the complicated non-steady-state motion. As a result, the grain boundary mobility values and migration enthalpy were not unique, but lay in a certain interval.

Motion of the Faceted 57° [11•0] Tilt Grain Boundary in Zinc. V.G.Sursaeva, A.S.Gornakova, V.P.Yashnikov, B.B.Straumal: Journal of Materials Science, 2008, 43[11], 3860-6