Achieving DFT accuracy in short range ordering and stacking fault energy using moment tensor potential for CoCrFeNi and CoCrNi
Phys. Rev. Materials 10, 053801 – Published 8 May, 2026
DOI: https://doi.org/10.1103/nqsc-gzkw
Abstract
A Moment Tensor Potential (MTP) is developed for equiatomic CoCrNi and CoCrFeNi alloys to enable large-scale simulations of chemical short-range order (CSRO) and defect energetics with near density functional theory (DFT) accuracy. The training database includes unary to quaternary configurations as well as DFT derived short-range ordered structures, ensuring accurate representation of thermodynamically relevant chemical environments. The MTP reproduces DFT energies, forces, stresses, and elastic constants across diverse compositions and phases. Hybrid Monte Carlo/molecular dynamics simulations recover key CSRO trends, including Cr–Cr and Fe–Fe repulsion and Ni–Cr ordering, with correct sign structure across temperature. Intrinsic stacking fault (ISF) energies are predicted to be for CoCrNi and for CoCrFeNi, consistent with DFT trends and sensitive to local chemical fluctuations. The potential further enables simulations of solute segregation at grain boundaries while preserving structural units. The developed MTP enables transferable, physically consistent simulations of thermodynamic stability and defect mediated mechanical response in fcc medium entropy alloys across extended length and timescales.
