Abstract
The <1126>{1121} pyramidal slip in Ti3Al shows the so-called yield stress anomaly. Near the peak-stress temperature, specimens collapse by shearing on {1121} slip plane almost immediately after yielding. Transmission electron microscope study revealed that pairs of unlike 1/6<1126>{1121} superpartial dislocations coupled by antiphase boundaries were generated in the same temperature range. These superpartials are of edge in character and are shown further to climb-dissociate on the basal plane into partials of smaller Burgers vector bounding a complex stacking fault: the dissociation is described by an equation 1/6<1126>→1/6<1013>+1/6<0113>. Fracture of single crystals at high temperatures is associated with locking of 1/6<1126> superpartials by climb dissociation.
