The interaction between extended dislocations and antiphase domain boundaries — II: uncoupled superpartial dislocations and planar slip

Due to their interactions with antiphase domain boundaries, superdislocations can move effectively as uncoupled superpartial dislocations in ordered structures. It is shown that there is a critical domain size below which this will occur irrespective of the grain size and APB energy. Our analysis also indicates that, because of superdislocation/domain boundary interactions, the stress required to move a superdislocation on a ‘fresh’ slip plane is maximum. Once superdislocations glide over a slip plane, an increasingly easy slip channel is created for the following superdislocations gliding on the same plane. Therefore, planar slip is expected. The smaller the APD size, the more likely is planar slip.