等温凝固多晶粒生长相场法模拟

采用Kim模型，利用耦合溶质场的相场模型对Al-2-mole-Cu合金等温凝固过程中多晶粒相互影响下枝晶的生长过程进行数值模拟，为了提高计算效率，采用差分去实现宏微观场之间的耦合.研究了不同过冷度对多晶粒枝晶形貌和溶质分布的影响，结果表明：成分过冷对枝晶生长速度和溶质分配有着重大的影响，溶质元素Cu在固液界面前沿重新分布，结果导致实际热过冷减小，进而影响枝晶的生长和溶质向外层的扩散，致使相互接触的枝晶产生萎缩而其余没有受到抑制的枝晶生长方向产生择优现象. 关键词： 相场法 模拟 择优生长 等温凝固 二元合金

Simulation of multiple grains for isothermal solidification of binary alloy using phase-field model

The phase-field model based on Kim model which couples the solute field is used to simulate microstructural dendrite growth of multiple grains for Al-2-mole-Cu alloy. In order to improve the efficiency of calculation, an interpolative method is used to achieve the coupling of the macro field with the micro field. The influence of different undercooling on shapes of dendrites and distribution of solute is studied.The result shows that the re-distribution of solute can decrease the melting point of the alloy, and reduce the practical undercooling, so the constitutional supercooling can influence the growth rate and solute distribution of dendrites by decreasing the freezing point evidently, and at the same time results in the cease of growth for both collided dendrites and perferred growth in directions of unhindered grains.