The Equilibrium with Freeze-in Temperature Model calculates equilibrium at the freeze-in temperature and evaluates the properties at a different temperature. The assumption is that diffusion and phase transformations are negligible when changing from the freeze-in-temperature and, therefore, that the phase amounts and compositions of phases are kept at all other temperatures.
The electrical resistivity due to phase interface scattering is evaluated as the scattering constant times sum of the interaction between the volume fraction of all the phases. The contribution to thermal conductivity is assumed to be related to that of electrical resistivity, following the Wiedemann-Franz law. See references.
The plot shows the lattice parameters for gamma and gamma prime plotted against experimental data from Nathal et al. It is a one axis calculation of a Ni0.6Mo0.92Ta12.5Al1.83Ti10.5Cr3.3W alloy evaluated with a range of 20 °C to 1000 °C using the Equilibrium with Freeze-in Temperature Nickel Property Model in Thermo-Calc. The freeze-in temperature is set to 1000 °C.