SUPERDISLOCATION DISSOCIATION IN INTERMETALLIC COMPOUND Ni3Al

The dissociation of a [1-01] superdislocation in Ni 3Al was studied by computer simulation techniques using the embedded atom method (EAM). Three types of dissociation were obtained, depending on the initial position of elastic centers of the superdislocation. One is the stable planar dissociation that the superdislocation dissociates on only one {111} plane into a pair of 1/2[1-01] superpartials separated by antiphase boundary (APB). Another stable dissociation is that it occurs on two adjacent {111} planes joined by an intersecting {111} or (010) plane. The metastable one is that the dissociation occurs in T shape: the superdislocation dissociates on two intersecting {111} planes into three partials: one 1/2[1-01] partial and two widely separated 1/6〈112〉 Shockley partials with a complex stacking fault (CSF) in between.