摘要
开发了一种耦合并行-自适应网格划分算法的相场-格子玻尔兹曼方法来模拟hcp金属的等轴和柱状枝晶生长,重点讨论了重力驱动的自然对流以及自然对流与强制对流耦合对枝晶生长的影响。模拟结果表明,二维情况下的hcp金属枝晶在重力驱动的自然对流下呈现非对称生长,同时揭示了溶质偏析和溶质羽流的演化过程。研究得出,溶质羽流的形成是由枝晶的溶质阻塞和熔体流动时溶质传输之间的竞争决定的。引入适当的强制对流可以消除溶质羽流的形成并抑制枝晶尖端溶质浓度的局部波动。研究还发现,重力驱动的自然对流丰富了hcp金属3D枝晶形貌的多样性。
A phase-field lattice-Boltzmann method coupled with the parallel-adaptive mesh refinement algorithm is developed to simulate the equiaxed and columnar dendritic growth of hcp metal alloys.The effect of gravity-driven natural convection on the dendritic growth is discussed separately and also coupled with forced convection.The simulated results show the asymmetric dendritic growth of hcp metal alloys in two dimensions under gravity-driven natural convection,and reveal the evolution process of solute segregation and solute plumes.It can be concluded that the solute plume formation is determined by the competition between the solute blocking of dendrites and solute transport of the melt flow.Introducing an appropriate forced convection can eliminate the solute plume formation and dampen the local fluctuation of solute concentration in front of the dendrite tips.It is also found that the gravity-driven natural convection enriches the diversity of the 3D dendritic morphology of hcp metal alloys.
作者
吴孟武
田冰辉
张昂
郭志鹏
熊守美
Meng-wu WU;Bing-hui TIAN;Ang ZHANG;Zhi-peng GUO;Shou-mei XIONG(Hubei Key Laboratory of Advanced Technology for Automotive Components,Wuhan University of Technology,Wuhan 430070,China;National Engineering Research Center for Magnesium Alloys,Chongqing University,Chongqing 400044,China;School of Materials Science and Engineering,Tsinghua University,Beijing 100084,China)
基金
financially supported by the National Natural Science Foundation of China(No.51805389)
the Key R&D Program of Hubei Province,China(No.2021BAA048)
the“111”Project,China(No.B17034)
the Fund of the Hubei Key Laboratory of Advanced Technology for Automotive Components,Wuhan University of Technology,China(No.XDQCKF2021011)。
关键词
枝晶生长
相场
对流
hcp金属
溶质羽流
dendritic growth
phase field
convection
hcp metals
solute plume
