Weak-beam study of superlattice dislocations moving on cube planes in Ni₃(Al, Ti) deformed at room temperature

Abstract

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