In the L12 structure, a superdislocation with a <110> Burgers vector could undergo one of two basic dissociations:

[110]  ½[110] + APB + ½[110]

or

[110]  1/3[112] + SISF + 1/3[112]

This was shown by observations carried out under weak-beam conditions in Zr3Al deformed at room temperature. Contrary to previous conclusions (Howe, Rainville and Schulson, 1974), it was found that superdislocations which dissociated via the second scheme coexisted with others which dissociated via the first scheme. The latter were commonly observed in Zr3Al, provided that the character of the parent dislocation was nearly screw. When the character was larger than about 40°, the second scheme was activated. Extended low-energy SISFs then appeared as the dominant feature within the microstructure.

A Dissociation Transition in Zr3Al Deformed at Room Temperature. J.Douin: Philosophical Magazine Letters, 1991, 63[3], 109-16