Composition stability of single fcc phase in Cr–Fe–Mn–Ni alloys: First-principles prediction and experimental validation

Abstract

The relative phase stability of fcc and bcc Cr–Fe–Mn–Ni alloys has been investigated using a combination of density functional theory, cluster expansion (CE), and Monte Carlo (MC) simulations. The MC simulations for fcc and bcc Cr–Fe–Mn–Ni alloys performed using the CE models enabled computing the Gibbs free energies of formation of 1767 fcc and bcc alloys in the whole range of compositions of each element and analyzed as a function of temperature. In order to determine regions of stability of single fcc/bcc structures and atomic fractions of these phases in two-phase regions, we constructed the thermodynamic databases (TDBs) derived from MC simulations with their application in the OpenCalphad calculations. The results obtained using this approach are in qualitative agreement with the available experimental data from the literature and the experiments performed within this work for the samples of [CrFeMn]100−xNix (x = 20, 25 and 35 at.%) alloys synthesized using arc-melting and annealed at 1273 K for 48 h. The analysis of fcc fractions of the near-equiatomic alloy compositions has enabled the identification of the alloys that are predicted to be single fcc phase for a wide range of temperatures.