c slip in Ti₃Al

Abstract

Strained Ti₃Al polycrystals exhibit local evidence of slip in the c direction on a [20] prism plane. Dislocation mobility appears to be affected in the edge and several specific mixed orientations by their interaction with the lattice. Segmentation of the dislocation lines along the <010> edge direction and, to a lesser extent, along the <012> and <013> mixed directions attests to pronounced first- and second-order Peierls valleys respectively. Contrary to what is usually observed in such processes, it is within about 30[ddot] from the screw orientation that dislocations appear to be the least affected by Peierls effects. Dislocation dissociation is not detectable under weak-beam conditions. It is pointed out that the favoured line orientations could originate from core spreading out of the prism slip plane possibly in the basal or second-order pyramidal planes for the edge orientation and in the first- and second-order pyramidal planes for the kinks.