Two-Sided Diffusion Quantitative Phase-Field Model for Isothermal Solidification of Multi-component Alloys

To achieve quantitative simulation of microstructure evolution during the solidification process of industrial alloys, this study extended one-sided diffusion quantitative phase-field model for isothermal solidification of multi-component alloys to two-sided diffusion one. The model was coupled with actual thermodynamic and kinetic data of the alloy, fully considering the interactions between different alloying elements. On the basis of eliminating the chemical potential jump at the interface, the anti-solute trapping coefficient Ai and phase-field mobility M in the two-sided diffusion quantitative phase-field model were redefined. Results show that taking Ti-45Al-8Nb (at%) ternary alloy as an example, 1D and 2D numerical simulations were conducted and compared with experimental results, validating the effectiveness of the established model in predicting the microstructure during solidification. The results provide theoretical support for further optimization of casting process and precise control of solidification microstructures.