Simulation and experimental validation of three-dimensional dendrite growth  

三维枝晶生长数值模拟及实验验证(英文)

作　　者：石玉峰[1] 许庆彦[1] 柳百成[1] 

机构地区：[1]清华大学机械工程系,先进成形制造教育部重点实验室,北京100084

出　　处：《Transactions of Nonferrous Metals Society of China》2012年第11期2756-2761,共6页中国有色金属学报（英文版）

基　　金：Projects (2005CB724105, 2011CB706801) supported by the National Basic Research Program of China;Projects (10477010, 51171089) supported by the National Natural Science Foundation of China;Project (2007AA04Z141) supported by the High-Tech Research and Development Program of China;Projects (2009ZX04006-041-04, 2011ZX04014-052) supported by the Important National Science & Technology Specific

摘　　要：A three-dimensional （3-D） modified cellular automaton （MCA） method was developed for simulating the dendrite morphology of cubic system alloys. Two-dimensional （2-D） equations of growth velocities of the dendrite tip, interface curvature and anisotropy of the surface energy were extended to 3-D system in the model. Therefore, the model was able to describe the morphology evolution of 3-D dendrites. Then, the model was applied to simulate the mechanism of spacing adjustment for 3-D columnar dendrite growth, and the competitive growth of columnar dendrites with different preferred growth orientations under constant temperature gradient and pulling velocity. Directional solidification experiments of NH4Cl-H2O transparent alloy were performed. It was found that the simulated results compared well with the experimental results. Therefore, the model was reliable for simulating the 3-D dendrite growth of cubic system alloys.建立了用于模拟立方晶系合金三维枝晶生长的改进元胞自动机模型。该模型将枝晶尖端生长速率、界面曲率和界面能各向异性的二维方程扩展到三维直角坐标系,从而能够描述三维枝晶生长形貌演化。应用本模型模拟在确定温度梯度和抽拉速度条件下三维柱状晶生长过程的一次臂间距调整机制和不同择优取向柱状晶之间的竞争生长。使用NH4Cl?H2O透明合金进行凝固实验,模拟结果和实验结果吻合较好。

关 键 词：modified cellular automation 3-D dendrite morphology dendrite growth directional solidification NH4Cl-H2O transparent alloy 

分 类 号：O782[理学—晶体学]