Mechanical properties and dislocation structure in L1₂long-range ordered Ni₃Fe

Abstract Although Ni3Fe belongs to the group of L12 long-range ordered intermetallics the critical resolved shear stress (CRSS) does not depend strongly on the deformation temperature. Dipoles and bundles of dipoles near edge orientations are characteristic features in the dislocation structure. Few screw superlattice dislocations are observed. There are striking similarities to the dislocation structure of pure f.c.c. metals or dilute solid solutions after low and medium plastic deformation. Cross-slip of screw superlattice dislocations onto cube (010) planes plays a minor role and is not regarded to be the rate-controlling factor for dislocation motion. The reason for the absence of cube cross-slip is the high activation enthalpy necessary to constrict widely dissociated Shockley partials to form unit screw superlattice partials.