High-resolution transmission electron microscopic observations of <110> symmetrical tilt boundaries showed that, at a boundary near to the incoherent (112¯)  = 3 coincidence boundary, there existed a periodic structure which consisted of 2 types of atomic arrangement. One was a mirror-symmetrical atomic arrangement in crystals adjacent to the boundary, and the other was a periodical mixed structure of mirror-symmetrical and asymmetrical arrangements. Two types of asymmetrical structure were observed; depending upon a slight deviation from the ideal misorientation. This fact was explained by a displacement shift discrete dislocation (b = a/6[112¯]) and lattice dislocation (b = a/2[011¯]) which extended on their boundaries after dissociating into 2 partial dislocations. The periodic structures which were observed at the boundary could be explained in terms of displacement shift discrete dislocations that were based upon the coincidence site lattice model and boundary dislocations which were predicted by the O-lattice model.

K.Morita, S.Tsurekawa, H.Nakashima, H.Yoshinaga: Journal of the Japan Institute of Metals, 1995, 59[9], 881-8