The (111) intrinsic stacking fault energy γISF in Ni and Ni-Co alloy was calculated and compared using two different ab initio methods, viz., the super-cell approach and the axial interaction model, based on density functional theory. The super-cell approach uses energies of crystal structure in slab geometry with and without the stacking fault. In the axial interaction model approach, the problem was mapped to a 1D spin-model and the interaction parameters were obtained using energies for ordered structures, thus obviating the need to handle faulted structure. For elemental Ni, the calculated values of γISF from the axial interaction model and super-cell approaches differ by not more than by 2%, and compares well with experimental value. For Ni-Co alloy, the axial interaction model predicts a slightly faster decrease in γISF with increasing Co concentration compared to super-cell approach and experimental data. Overall, there was good agreement between the two approaches.

First-Principle Calculation of Stacking Fault Energies in Ni and Ni-Co Alloy. M.Chandran, S.K.Sondhi: Journal of Applied Physics, 2011, 109[10], 103525