Low energy planes for tilt grain boundaries in gold

Abstract

Thin film bicrystals of gold were annealed to create a large variety of grain boundaries of controlled crystal misorientation. The faceting of these boundaries was studied, and some low-energy boundary planes were identified. Tilt boundaries with a (100) misorientation axis were found to facet more readily than those with a (100) axis. The results were considered in terms of O-lattices and coincident site lattices, but neither of these approaches is able to explain all the observations. Consequently, no simple and general criteria, based on geometrical considerations, were found for the occurrence of grain boundary planes of low energy. A further set of observations relates to the dissociation of some specific high-angle grain boundaries into a twin and another low-energy boundary. Boundaries with a ..sigma..33 coincidence site lattice relationship frequently appear to be characterized by a relatively low energy. 12 figures, 2 tables.