Superdislocation core structures in L12 Ni3Ge, Fe3Ge and Ni3Al were determined on the basis of ab-initio generalized stacking fault (GSF) energetics calculations. Superdislocation dissociation schemes, partials separation and core widths were calculated within the modified Peierls-Nabarro (PN) model with ab-initio GSF parameterization. Calculated superdislocation core structure parameters were found to be in agreement with available experimental data. The superdislocation core with type I (fourfold) dissociation was found to be unstable in Fe3Ge but stable and energetically preferred in Ni3Ge and Ni3Al. These results allows us to suggest a mechanism for the octahedral glide being inactive in Fe3Ge which is found to be different in several aspects with those discussed so far in the literature.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys