Multiplied dislocations in single crystals having the Ll2 structure were studied via the weak-beam technique of transmission electron microscopy. Non-screw dislocations multiplied on {111} planes at low temperatures were shown to be dissociated into two unit dislocations with b = a/2<110> bounding the antiphase boundary on the {111} plane. The energy was estimated to be 110mJ/m2. Straight screw dislocations were found to have undergone a sessile transition via the Kear-Wilsdorf mechanism. Dislocations multiplied on {100} plane at high temperatures were widely dissociated, bounding an antiphase boundary on the {100} plane whose energy was 17mJ/m2. The energy criterion for the dissociation schemes of a superlattice dislocation on a {111} plane in the L12 structure was calculated, based upon the isotropic elasticity theory of dislocations.

Dissociated Structure of Superlattice Dislocations in Ni3Ga with the L12 Structure. K.Suzuki, M.Ichihara, S.Takeuchi: Acta Metallurgica, 1979, 27[2], 193-200