First-principles density functional theory study of phase transformations in NbCr2 and TaCr2

Basal slip in Laves phases: The synchroshear dislocation

“…The Eb computed in Ref. [8] for US in C14 Cr2Nb (0.28 eV/Cr2Nb) is nearly the same as the Eb of SS in the same system (0.29 eV/Cr2Nb) [7]. Further, the Eb calculated for SS in Ref.…”

“…The initial NEB configurations have been linearly interpolated between the two perfect C14 Simultaneously, the glide of the middle-layer Mg atoms is $ % 〈101 ) 0〉. Without any assumption on the mechanism beside the Burgers vector of the full slip and that the linear interpolation lies in the same energy well as the MEP, it is clear that the MEP of a full shear in the C14 Mg2Al structure corresponds exactly to two successive SSs [5,7].…”

Layer-stacking irregularities in C36-type Nb–Cr and Ti–Cr Laves phases and their relation with polytypic phase transformations

“…In case of Laves phases, the Gibbs energies of the different layer-sandwich unit stacking modifications differ only slightly (e.g. [25]) and hence the stacking fault energy is also low. Thus, deviations from perfect "ordered glide" are likely.…”

Polytypic transformations of the HfCr2 Laves phase – Part II: Kinetics of the polymorphic C14 → C15 transformation

“…The majority of previous works on kinetic aspects of these transformations was of theoretical character [5,19,20]. In a recent experimental work the activation energy for the C14 / C36 transformation of TiCr 2 has been reported to be in the range 107e112 kJ/mol [21].…”