AI 中文总结
研究快速合金凝固微观结构预测问题，核心方法是基于优化校准策略将目标响应函数嵌入相场公式获优化扩散率函数，主要贡献为证明模型准确性通用性、研究溶质拖拽影响及扩展到多元合金，为相关模拟提供途径。
AI 中文摘要
快速凝固微观结构的定量预测需要能表示界面性质速度依赖性的相场模型，如溶质分配、动力学液相线响应、溶质拖拽和动力学过冷。这些响应函数控制微观偏析和形态选择，但在相场模拟中难以准确规定。本文引入基于优化的校准策略，通过将界面扩散率插值函数视为响应匹配自由度，将目标尖锐界面响应函数嵌入稀合金相场公式。从一维稳态相场解获得优化扩散率函数，以再现规定的连续生长模型目标。通过在稀Al-Cu中再现规定响应函数证明校准模型的准确性和通用性，并进行二维定向凝固模拟研究溶质拖拽的影响。还将公式扩展到稀多元合金。该框架为将非平衡界面动力学纳入快速凝固合金的定量相场模拟提供了途径。
英文摘要
Quantitative prediction of rapid solidification microstructures requires phase field models that represent the velocity dependence of interfacial properties, including solute partitioning, kinetic liquidus response, solute drag, and kinetic undercooling. These response functions control both microsegregation and morphology selection, but are difficult to prescribe accurately in phase field simulations that employ large interfaces for numerical efficiency. We introduce an optimization-based calibration strategy that embeds target sharp-interface response functions into a dilute alloy phase field formulation by treating the interfacial diffusivity interpolation function as a response-matching degree of freedom. The optimized diffusivity functions are obtained from one-dimensional steady-state phase field solutions, constrained to reproduce prescribed continuous-growth-model targets for velocity-dependent solute trapping and drag-modified liquidus kinetics. We demonstrate the calibrated model's accuracy and versatility in dilute Al-Cu by reproducing the prescribed response functions for intermediate solute drag coefficients relevant to rapid solidification. Two-dimensional directional-solidification simulations are conducted to isolate the effect of drag at fixed composition, thermal gradient, and pulling velocity. We show that increasing solute drag shifts the solidification morphology from dendritic/cellular growth to mixed dendritic-banded structures, and finally to predominantly banded growth. We extend the formulation to dilute multicomponent alloys, enabling independent specification of equilibrium partition coefficients and liquidus slopes for multiple solute species. The framework provides a route for incorporating experimentally, theoretically, or atomistically informed nonequilibrium interface kinetics into quantitative phase field simulations of rapidly solidified alloys.
Comments19 pages, 6 figures, 10 pages of Supplementary Material with 1 figure
