The diffusion of B was studied by means of plan-view and cross-sectional transmission electron microscopy. This showed that misfit dislocation half-loops were initially generated at the surface. The Burgers vector of the dislocation half-loop was inclined with respect to the surface, and the initial misfit dislocations were therefore not very efficient with regard to strain relaxation. As diffusion proceeded, non-parallel dislocations interacted and gave rise to product segments that had in-plane Burgers vectors which were parallel to the surface. On the basis of the observations, a model was presented in order to clarify the details of these interactions; and the formation or more efficient misfit dislocations from less-efficient inclined ones.

X.J.Ning, P.Pirouz: Acta Materialia, 1996, 44[5], 2127-43