Concerning the dissociation of grown-in dislocations in melt spun ribbons of the intermetallic compound Nb3Al

The nature of 'grown-in' dislocations formed in melt spun ribbons of the compound Nb 3 Al have been studied using transmission electron microscopy. These dislocations have b = ⟨100⟩ and are predominantly screw in character. They are dissociated into two partial dislocations which bound a complex stacking fault according to the reaction The habit plane of the fault is shown to be {012}. These observations are compared with previous studies performed on the isostructural compound V 3 Si and the consequences of the observed dissociation for the plastic deformation of A15 compounds are discussed.