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

Abstract

The nature of ‘grown-in’ dislocations formed in melt spun ribbons of the compound Nb₃Al 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 V₃Si and the consequences of the observed dissociation for the plastic deformation of A15 compounds are discussed.