Cu-Zn system is one of the most widely used nonferrous alloys. The system is also interesting since it exhibits SME. SME is explained by martensitic transformation from high temperature ordered phase to low temperature ordered phase. In the prediction of transformation temperature in SME, it is necessary to have composition and temperature dependence of thermodynamic properties and order parameters. However such information is unavailable in Cu-Zn system.
In this work, relative free energies of various phases in Cu-Zn system were numerically formulated using subregular solution model and existing thermodynamic data. Interchange energies were also formulated as a linear function of composition by using the numerically formulated relative free energies and modified BWG model. By using the calculated values, the variation of transformation temperature was predicted as a function of composition. Variation of order parameters were also predicted as a function of temperature and composition.