Abstract
The dislocation structure resulting from the compression of single crystals of Ni3(Al,Ti) at room temperature has been studied using transmission electron microscopy imaging methods. Deformed samples of ε = 1% and ε = 9% true strain were sliced parallel to (111) and (010) planes. Weak-beam imaging methods reveal the (010) planes to be the dissociation planes of the screw superlattice dislocations. Transition of superlattice dislocations from (111) onto (010) planes by the Kear-Wilsdorf mechanism was identified. Remarkable dislocation movement on (010) planes was found. The flow stress is interpreted as a dislocation interaction on octahedral and cube planes. Measurements of the antiphase-boundary energies on (111) and (010) planes yielded values of γ111 = γ010 =250±30mJm−2