End-on images of dislocations in Ni3(Al,Ti) single crystals, deformed at 683 or 293K, were studied using high-resolution transmission electron microscopy. They showed a superlattice intrinsic stacking-fault type of dissociation on a {111} plane and an antiphase boundary type of dissociation on a {001} plane. The superlattice intrinsic stacking-fault and antiphase boundary energies were calculated to be 133 and 560mJ/m2, respectively, by using isotropic elasticity theory, and were compared with results obtained via field ion microscopy, weak-beam techniques and high-resolution electron microscopy. It was suggested that a decrease in dissociation distance, due to the Ti addition, resulted in an increase in the strength anomaly.

High-Resolution TEM Observations of Superdislocations in Ni3(Al,Ti). T.Kawabata, D.Shindo, K.Hiraga: Materials Transactions, 1992, 33[6], 565-70