A transmission electron microscopic study was made of a vicinal 78.7° high-angle grain boundary, in pure Ti, which had a mixed tilt-twist nature and which exhibited a characteristic dislocation arrangement. It was noted that there was no feasible constrained coincident-site lattice which could be used as the reference structure by this boundary. An alternative structure was proposed which corresponded to a 2-dimensional atomic arrangement that was inclined by about 18° with respect to the boundary plane. The dislocation configuration which was required in order to accommodate the deviation from the reference structure orientation was predicted by using an O-lattice algorithm for interfacial dislocations. The modelled configuration gave a good semi-quantitative match to the experimental observations; thus confirming that the proposed reference structure was the one adopted by this boundary. It was proposed that periodic, or nearly periodic, 2-dimensional arrangements could provide a more physically significant model for the reference structures adopted by vicinal high-angle grain boundaries.

Analysis of the Reference Structure Adopted by a Mixed Tilt-Twist Vicinal High-Angle Grain Boundary in Titanium I.MacLaren, M.Aindow: Philosophical Magazine A, 1997, 76[4], 871-88