Weak fringing faults were observed, using transmission electron microscopy, in planar slip bands in a Ti-6wt%Al alloy. The magnitude of the contrast increased with the number of dislocations which sheared a particular region of the slip plane, and the fringe contrast saturated along a slip band. The fault fringes were found to be caused by a residual displacement of the form, R = (1/n)<11•0>. The upper bound on the magnitude of R for prism slip bands was estimated to be between (1/145)<11•0> and (1/104)<11•0>

by using quantitative image-matching simulations. The sign of R was found to be anti-parallel to the direction of the Burgers vector of a-type dislocations in the slip bands. It was also observed that the fringe contrast was always weaker for basal slip bands. A comparison with image simulations indicated that the magnitude of the residual displacement was smaller on the basal plane. The residual displacements were attributed to relaxation processes that were associated with the destruction of short-range order.

Observation and Analysis of Weak-Fringing Faults in Ti-6wt%Al. T.Neeraj, M.J.Mills: Philosophical Magazine A, 2002, 82[4], 779-802