In previous publications the present authors proposed a method to incorporate the thermodynamics of ternary alloys and liquid diffusion-governed solidification kinetics into a multiphase volume average solidification model [23,24]. Back diffusion was disregarded. A way to access the thermodynamic data (e.g. Thermo-Calc [1]) through a tabulation and interpolation program ISAT (In Situ Adaptive Tabulation) was suggested. With the ISAT approach it is possible to perform an online call of the thermodynamic data and trace the formation of each individual solid phase (primary, peritectic, eutectic, etc.). As the number of calls of the thermodynamic data is equal to the product of the number of the discretized volume elements, the time steps and the calculation iterations per time step, the calculation becomes exhausting. Therefore, the current model is a modification of the previous model using a linearized phase diagram, and no online call of thermodynamic data is necessary. In addition, the model presented in this paper is extended to consider the back diffusion into the solid. With these modifications, the model can be used to perform casting process simulations with incorporated full diffusion-governed solidification kinetics for ternary alloys at a reasonable computation cost.
