A  = 5 (210)/[001] symmetrical tilt grain boundary was produced by the diffusion bonding of precisely oriented single crystals in an ultra-high vacuum environment. The atomic structure of the boundary was characterized by means of high-resolution transmission electron microscopy. Atomic models of the coincident site lattice boundary were constructed, and a comparison of the model structures with high-resolution micrographs was carried out using high-resolution image simulation. The resultant models were equivalent to twins at the atomic scale. The high-resolution images revealed no rigid crystal translations away from the perfect mirror reflection relationship. It was noted that many aspects of the boundary structure were properly reproduced by the models, while some details of the high-resolution images indicated that discrepancies remained. Thus, the atomic model was in good agreement with experimental images when viewed parallel to the tilt axis, but disagreed with images perpendicular to the tilt axis. The agreement between the simulated images and experimental images could be improved by changing the composition of the grain boundary with respect to the bulk.

G.H.Campbell: Journal of the American Ceramic Society, 1996, 79[11], 2883-91