The preliminary results of a high-resolution electron microscopic study of grain boundary structure in bulk nanocrystalline material were presented. A recently developed method of image analysis was applied to an experimental image of a grain boundary between 2 grains. Maps of the fringe spacing and of the local rotation of the lattice were produced as a function of position in the image. An analysis of the fringe spacing showed that no oxide layer existed between the grains. This confirmed that the surface oxide layer coating the particles could be eliminated during the formation of the bulk material. By studying the manner in which rotation of the lattice took place across the grain boundary, an upper limit for the interface width was obtained.

Evidence for Crystallographically Abrupt Grain Boundaries in Nanocrystalline Copper. Y.Champion, M.J.Hytch: European Physics Journal, 1998, 4[2], 161-4