The intersection of deformation twins with 2 plates, in a 2-phase -phase alloy that had been deformed at room temperature, was investigated by means of transmission electron microscopy. Two types of configuration could be distinguished, depending upon the orientation of the intersection line. In the case of type-I intersection along a line that was parallel to <110], the deformation twins were blocked by the 2 plate. At these intersections, ordinary glide dislocations were emitted back into the  matrix on cube slip planes. This was accompanied by twinning in ; parallel to the /2 interface. No transfer of shear across the /2 interface was observed in this case. In the case of type-II intersections with a line that was parallel to <110], the incident twinning shear was usually associated with a-type slip on {1¯1•0} planes in the 2 plate. On one occasion, {2¯2•1} twinning was observed in the 2 plate at the intersection. The observations were analyzed by taking account of all possible dissociations of one or more twinning partial dislocations into 2 glissile dislocations, or into 1 glissile dislocation (glissile in the matrix or plate) and a residual interface dislocation. This was done by considering various conditions for the dissociation of twinning partials at the intersection and for subsequent relaxation via slip. These conditions were similar to those which had been reported for twin-twin intersections in the  phase, and for slip transfer at grain boundaries in metals. Analysis showed that, for a particular dissociation, not all of the conditions could be fulfilled at the same time. There was an order of priority among the conditions. These were: a common line of intersection with the interface of the incoming twinning plane and the relaxation slip planes, slip directions (of the glissile product dislocations) which were consistent with the applied load, zero or small residual interface dislocations, and a high value of the Schmid factor.

Y.G.Zhang, F.D.Tichelaar, F.W.Schapink, M.C.Chaturvedi: Materials Science and Engineering A, 1996, 219[1-2], 162-79