| Abstract Scope |
CALPHAD is a leading method for modeling and calculations of phase equilibria in materials. However, the prevailing solution model used in CALPHAD, the sublattice model, is an empirical mean-field model based on the ideal entropy approximation, which makes CALPHAD inadequate for describing chemical short-range order (SRO) in alloys. Here we develop a hybrid framework by marrying advantages from the Cluster Variation Method and CALPHAD through incorporating chemical SRO into CALPHAD with a novel cluster-based solution model. We have put more physics into CALPHAD, while maintaining its practicality and efficiency. The configurational and non-configurational (vibrational, elastic, electronic) contributions to free energy are modeled separately, gaining insights into their respective effects on phase stability. Phase diagrams of representative alloy systems are calculated, showing great comparison with experiments. This hybrid CVM-CALPHAD framework represents a new methodology for thermodynamic modeling that enables SRO to be exploited for the design of novel complex concentrated alloys. |