多元合金等温凝固的双边扩散定量相场模型

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

摘要:

为实现工业合金凝固过程中微观组织演化的定量模拟，本研究将多元合金等温凝固的单边扩散定量相场模型扩展为双边扩散模型，并与合金实际的热力学和动力学数据进行耦合，以充分考虑多组元合金成分之间的相互作用。在消除界面化学势跳跃的基础上，重新确定了双边扩散定量相场模型中的反溶质截留系数A_i和相场迁移率M。结果表明：以Ti-45Al- 8Nb（at%）三元合金为例，进行了一维（1D）和二维（2D）数值模拟，并与实验结果进行对比，验证了所建立模型在合金凝固过程中对微观组织预测的有效性。研究结果为进一步优化工业合金的铸造工艺和凝固组织的精准调控提供了理论支撑。

Abstract:

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 A_i 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.