Effect of faceting on grain boundary motion in Zn

The impact of faceting on the motion of a high-angle grain boundary (GB) in Zn was studied. The steady-state motion of a [101¯0] tilt GB half-loop was recorded in situ. Above 673 K the migrating GB half-loop was continuously curved. Below this temperature a facet appeared and coexisted with the curved GB. The length of the facet increased with decreasing temperature. The temperature dependence of the facet length and the steady-state motion of the GB half-loop with and without facet was investigated. A theory for the motion of a faceted GB is presented. It allows us to account for the observed phenomena and to extract the mobility and the temperature dependence of a moving facet.