It was recalled that the atomic-scale structures of face-centered cubic oxide and metal grain boundaries were habitually investigated by means of high-resolution electron microscopy. Attention was here focused on the examination of structures that evolved when the grain boundary deviated from the ideal planar periodic geometry. Examples were given of atomic-scale grain boundary steps, with and without a dislocation character. The misorientation dependence of atomic-scale grain boundary structures was investigated in <110> tilt grain boundaries of Au near to the (113)(113) low-energy cusp. Common grain-boundary relaxation modes included those of stacking disorder, low-index asymmetrical facets and micro-facets. All of the observed structures and atomic relaxation modes in grain boundaries were consistent with the short-range nature of the interatomic interactions which led to misfit localization and a tendency to preserve the atomic coordination of the defect-free solid.

K.L.Merkle: Journal of the Physics and Chemistry of Solids, 1994, 55[10], 991-1005