Grown-In and Shear-Produced APB Faults in Ordered Intermetallics

Antiphase Domain Boundaries play an important role in phase changes and microstructural stability of ordered alloys and intermetallics as well as affecting mechanical behaviour. The origin of APB faults in annealed material is examined here, and in particular the differences between a sharp boundary, as produced by crystal shear, and a relaxed fault structure are emphasized. The kinetics of relaxation of a shear-produced fault are examined and it is shown that fast relaxation may greatly affect the movement of dislocations by creating locking stresses as well as affecting cross slip behaviour, and hence significantly affecting mechanical properties.