Extension of the modified quasichemical model in the distinguishable-pair approximation to multicomponent solutions via an on-the-fly interpolation framework

Abstract

The Modified Quasichemical Model in the Distinguishable-Pair Approximation (MQMDPA) was originally developed to describe thermodynamic properties of binary solutions with manifold short-range ordering (SRO) among atoms. This study extends the MQMDPA to multicomponent solutions through the development of an on-the-fly bond-energy formalism (OTFBEF). The OTFBEF employs interpolation functions to dynamically transform bond energy expressions from binary to ternary and higher-order multicomponent systems. By fixing the interpolation functions to specific values, the OTFBEF seamlessly reduces to traditional geometric methods, the generic method, or the hybrid Kohler-Toop loop framework, ensuring compatibility with established approaches, particularly with the widely used MQMPA. The interpolation functions can be optimized using experimental data from ternary systems or theoretically defined through integral and partial methods, providing flexibility for both prediction and calibration. The versatility and generality of the OTFBEF empower the MQMDPA to model multicomponent solutions with complex configurations effectively. Future work will focus on expanding the MQMDPA within a two-sublattice framework to address reciprocal solutions, further enhancing its applicability.