It was noted that disorder-to-order reactions in the stoichiometric alloys involved a face-centered cubic to tetragonal (D022) transformation. The structural changes which occurred during the transformation resulted in a lamellar morphology of D022 domains, with {110}fcc-type interfaces. The propagation of stacking faults across domain boundaries was studied using transmission electron microscopy. Various modes of propagation of the stacking faults across the boundaries were observed. These modes were explained in terms of the generation of suitable gliding partials at the domain boundaries. The nature, and Burgers vectors, of these partials were identified by using visibility/invisibility criteria. Computer simulation was used to confirm the results of contrast experiments. The dislocation-reaction mechanisms which were responsible for the generation of these gliding partials were identified. Particular emphasis was placed on the propagation mode in which stacking faults crossed domain boundaries in the same glide plane.

Propagation of Stacking Faults across Domain Boundaries in Ni-V and Ni-V-Nb Alloys with D022 Structure. J.B.Singh, M.Sundararaman, P.Mukhopadhyay: Philosophical Magazine A, 2000, 80[9], 1983-2010