Antiphase Domain Boundary Tubes in Ordered Alloys

Abstract

AbstractAPB tubes have been observed in both a B2 and an L12 ordered alloy by means of weak beamtransmission electron microscopy. The tubes are attached to near—edge dislocations, either to single superdislocations or to superdipoles. The majority appearto have been formed by cross slip of screw dislocations. A computer model of the cross slip process in B2 alloys is described. The tubes formed by cross slip drag on edge dislocations and are capable in principle of explaining the extra work hardening shown by ordered over disordered crystals. The temperature and orientation dependence of the work hardening are similar to those of the proof stress which is also thought to be controlled by cross slip. This new mechanism of work hardening is shown to give order of magnitudeagreement with experiment.