相场方法模拟铝合金三维枝晶生长

以相场模型为基础，采用宏微观耦合方法和界面捕获液态方法对铝合金枝晶生长进行模拟计算.为解决试样全场微观计算的困难，采取宏微观耦合的计算方法，试样整体计算温度场，而微观组织计算只在一个确定的宏观单元内进行，宏观微观计算交替耦合进行.在不改变相场模型的条件下，提出界面捕获液态计算方法.赋值计算单元界面标志，只对界面处的单元求解相场变量，当枝晶生长时，捕获液态单元为界面从而推进界面，并对捕获到的单元校正相场变量.通过界面捕获液态方法加速相场模型的计算，实现了铝合金试件局部三维单晶粒和多晶粒的模拟.对模拟结果与实关键词：相场方法液态捕获微观组织枝晶

Simulating the three-dimensional dendritic growth of Al alloy using the phase-fi eld method

Numerical simulation of three-dimensional dendritic growth is performed by using a macro-micro coupled method and a capturing liquid method. The growth of the dendritic is controlled by the solution of the phase field equation. Since it is difficult to compute the microstructure of a whole casting, a scheme is adopted that the temperature field is calculated on the whole casting while the microstructure computation is carried out by selecting a macro-cell in the casting samples. Under the condition of not changing the phase-field model, a calculating method is advanced, which captures the liquid cells into the interface ones. In that method, every calculated micro-cell is endowed with a variable which identifies whether the cell is in the interface region and the phase field equation is only solved for those cells in that region. When the grain grows, the method captures the liquid cells into the interface ones and pushes the interface regi on forward. For the captured liquid cells, the values of the phase variable are modified. We apply the calculating method to improve the calculating efficiency, so the simulation of three-dimensional single grain and multiple grains growth for aluminum alloy samples, can be processed. The simulation results are compared with those obtained experimentally.