Phase equilibria and thermodynamics of binary copper systems with 3d-metals. IV. Copper-manganese system

Thermodynamic properties of alloys and phase diagram of Cu-Mn system have been assessed in the spirit of the CALPHAD-approach using simultaneously data about thermodynamic properties of phases and their equilibria. Thermodynamic data are known only for liquid and (Cu, γMn)-phase, model parameters for (δMn)-and (βMn)-phases were therefore estimated using phase equilibria data. The excess Gibbs free energy of phases is described by models with Redlich-Kister polynomials. The models of Gibbs free energy of liquid and (Cu, γMn)-phase take into account excess heat capacity of these phases. Thermodynamic model of the system provides a self-consistent description of all thermodynamic values and phase equilibria, including metastable immiscibility of (Cu, γMn)-phase in close agreement with experimental data. Low-temperature part of the diagram is added in accordance with published data on ordering reactions in (Cu, γMn)-phase.