Evaluation of slip patterns observed in association with deformation twins in Mo-35 at%Re alloy

Abstract

The crystallographic features of twins terminating inside the grains and of associated emissary slip have been correlated using transmission electron microscopy. It is observed that when the slip patterns are simple, the Burgers vector of slip dislocations is always parallel to the direction of the twinning shear; this conclusion is consistent with the suggestions of Hull (1961, 1964) and Sleeswyk (1962). It is proposed that the emissary sub-structures evolve to relax the stresses at the tips of the twins which have stopped growing inside the crystal, and their evolution could be rationalized in terms of Hull's coalescence model. It is suggested that the coalescence reaction is more likely to occur than the dissociation reaction proposed by Sleeswyk, because the former is energetically less unfavourable.