Kear-Wilsdorf locks and the generation of antiphase-boundary tubes in L1 2 alloys

The two available mechanisms for antiphase-boundary tube formation under single-slip conditions are compared. Some of the assumptions involved such as the driving force for limited fast climb at jogs and the conditions for the transformation of Kear-Wilsdorf locks into dipoles are re-examined. Various implications of the two mechanisms are analysed and they are also compared with experimental observations in L1 2 alloys. It is shown that the trailing of APB tubes by climb-relaxed jogs offers explanations of current microstructural features that are often less constraining than the bypassing of Kear-Wilsdorf locks and subsequent dipolar cross-slip annihilation. Evidence is also provided in support of the generation of APB tubes by direct cross-slip annihilation confirming a manoeuvre originally proposed for B2 alloys.