Abstract
In the L12 structure, a superdislocation with a 〈110〉 Burgers vector may undergo either one of the following basic dissociation schemes: This is exemplified by observations carried out under weak-beam conditions in Zr3Al deformed at room temperature. Different from the conclusions drawn by Howe, Rainville and Schulson (1974), it is found that superdislocations dissociated under scheme (II) coexist with others dissociated under scheme (I). The latter are commonly observed in Zr3Al provided the character of the parent dislocation is nearly screw. It is when the character is larger than about 40° that scheme (II) is activated. Extended, low energy SISFs then appear as the dominant feature within the microstructure.