In order to study interface boundary structures, a 3-dimensional near-coincidence site lattice model, based upon Bollmann’s O-lattice method, was proposed. Previous studies had shown that intragranular α-phase precipitates in Ti-22V-4Al had a lath-like morphology, with 2 well-defined facet planes. Detailed transmission electron microscopic observations were made of the laths. The accommodation mechanism of misfit dislocations, and the Burgers vectors of the defects observed at the broad face and side

facet plane of the intragranular α-phase precipitates were determined. The structural ledges on the side facet, as predicted by the present analysis, were consistent with the high-resolution transmission electron microscopic observations. The Burgers vector of misfit dislocations at the broad face was in good agreement with that previously reported for a Zr-2.6Nb alloy which had almost the same lattice parameter ratio as the present alloy. Although the Burgers vector of the defects on the broad face could be determined by high-resolution transmission electron microscopy, the boundary plane was not well-defined. However, it was demonstrated that the interface boundary structure of the broad face could be rationalized in terms of both the near-coincidence site lattice analysis and the high-resolution transmission electron microscopic observations.

HRTEM Observation and Atomic Modelling of α/β Interphase Boundary in a Ti-22V-4Al Alloy. N.Miyano, K.Ameyama, G.C.Weatherly: Materials Transactions, 2002, 43[7], 1547-51

 Table 6

 Diffusivity of Fe in Zr41Be27.8Ti8.7Cu12.5Ni10