Dissociation of a dislocation into partial dislocations bounding an unstable stacking fault

Though a stable stacking fault is usually assumed to exist for a dislocation to dissociate into partial dislocations, we show in this paper that a dissociation can occur even when the stacking fault is unstable. In the case where both the undissociated and dissociated states are stable and the former state has the lower energy than the latter, a yield stress anomaly is expected to occur because the metastable state can have much higher mobility than the stable state.