Transfer mechanisms of deformation at ordered domain interfaces in polysynthetically twinned alloys were studied by means of in situ straining at room temperature in a transmission electron microscope. Several situations were analysed which differed with regard to the nature of the incident dislocations and the orientation of the applied stress. Some cases were considered for which no dislocations were emitted in the second lamella. The interpretation of the results was based upon a geometrical analysis of the various situations, and calculations of the stress distributions due to the applied stress and to pile-ups of dislocations at the interface. The emission of dislocations was found to occur if the applied stress and the internal stress were favourable. When the incident system was formed by a twin, ordinary and superlattice dislocations were emitted in the second lamella in the plane; as a continuation of the glide plane of the incident dislocations. When the incident system consisted of ordinary dislocations, Shockley dislocations which resulted from dissociation of the incident dislocations were emitted in the plane which contained their Burgers vectors.

Transmission of the Deformation through γ-γ Interfaces in a Polysynthetically Twinned TiAl Alloy - I. Ordered Domain Interfaces (120° Rotational). S.Zghal, A.Coujou, A.Couret: Philosophical Magazine A, 2001, 81[2], 345-64