The interaction between extended dislocations and antiphase domain boundaries — I: superpartial separation and the yield stress

The interaction between an extended superdislocation in an ordered structure and an antiphase domain boundary (APB) has been analysed. In contrast to previous treatments (Cottrell AH. Relation of properties to microstructure. ASM Monograph 1954. p. 131; Ardley GW. Acta Metall 1955;3:525) we include the effects of (i) the small strip of perfect crystal within an extended dislocation straddling an APDB and (ii) the ledge in an APDB which has been cut by a dislocation. We also revisit the concept of ‘APDB thickness’. The new analysis leads to a more marked variation of superpartial separation with domain size than previously calculated and also predicts a variation of yield stress with domain size which is in better agreement with experiment than are previous calculations.