Unusual dissociation of dislocations in Ni₃Ta

Dislocations in ordered Ni₃Ta are examined by transmission electron microscopy. [100] super‐dislocations dissociate visibly into two dislocations both of which presumably consist of closely spaced partial dislocations. [001] super‐dislocations dissociate into two dislocations one of which is a partial dislocation and the other consists presumably of three very closely spaced partial dislocations. These dissociations seem to occur when the antiphase boundary energy is much larger than the stacking fault energy. The dissociation of the [100] superdislocations allows an estimation of the order fault energy which is found to be of the order of 130 erg/cm².