The conditions for the existence of extended 2c+a super-dislocations in the first- and second-order pyramid planes of an ordered alloy with the D019 structure were analyzed. The thermally activated transformation of glissile super-dislocations into dislocation barriers, that occurred due to cross-slip of part of a c+a/2 super-partial dislocation onto a basal or pyramidal plane, was studied. Activation energies for the formation of barriers were calculated as a function of the applied shear stress along the [00▪1] direction. This was done for various values of the parameters that characterized the dissociation of glissile and blocked super-dislocations in the present intermetallic compound. The activation energy for formation at edge dislocations, during passage of the partial dislocation onto the basal plane, was shown to be much higher than for the formation of barriers at screw dislocations during the passage of the partial dislocation onto the prism plane.

Thermally Activated Transformations of Glissile 2c+a Superdislocations in Alloys with a D019 Superstructure. L.I.Yakovenkova, L.E.Karkina, M.J.Rabovskaya: Physics of Metals and Metallography, 1999, 88[3], 190-5