The formation of intrinsic stacking-fault tetrahedra in deformed F.C.C. alloys

It has been suggested (Loretto et al. 1965) that triangular loops of Frank dislocation and stacking-fault tetrahedra in deformed f.c.c. metals and alloys are formed from a length of dislocation lying along the ⟨110⟩ perpendicular to its Burgers vector. Experiments have been done to determine the origin of this length of dislocation and it is concluded that the collapse of a dislocation barrier, which is expected theoretically to be only slightly extended, is the source of such dislocations. Consideration of this mechanism shows that intrinsic rather than extrinsic faulted loops and tetrahedra will invariably be formed simply because glide dislocations dissociate to form intrinsic faults.