Searching for new multi-component alloys with desirable stacking fault energies: The compositional dependency of binary interaction terms

The Calculation of Phase Diagrams (CALPHAD) method has proven useful in assessing the phase stability of multi-component alloys. This success does not extend to the prediction of stacking fault energy (SFE) in fcc systems. We propose this can be viewed as a consequence of the (largely unknown) compositional dependency of the binary interaction terms. To make the case, we compare CALPHAD-predicted SFEs with atomistic computations based on the axial Ising model. To facilitate the search for new multi-component alloys while acknowledging this shortfall in knowledge, we propose an approach whereby binary interaction terms are refined during the search. As an illustrative case study, we apply this method to a directed search for Cr-Fe-Ni alloys with reduced Ni contents while preserving the value of the SFE.