Phase-field models for anisotropic interfaces.
Phase-field models for anisotropic interfaces.
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DOI：
10.1103/physreve.48.2016
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发表时间：
1993-09
期刊：
影响因子：
--
通讯作者：
G. McFadden;A. A. Wheeler-A.;Richard J. Braun;S. Coriell;R. Sekerka
中科院分区：
文献类型：
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作者：
G. McFadden;A. A. Wheeler-A.;Richard J. Braun;S. Coriell;R. Sekerka
研究了在相场模型中引入各向异性表面自由能和各向异性线性界面动力学对纯材料凝固过程的影响。该配方描述为一个二维系统与一个光滑的晶体-熔体界面和表面自由能，随着取向的变化而平滑，在这种情况下，一个相当普遍的依赖性的表面自由能和动力学系数的取向可以被处理;它被假定为各向异性是足够温和的，失踪的取向不会发生。匹配渐近展开的方法是用来恢复适当的各向异性形式的吉布斯-汤姆逊方程在尖锐的接口限制，其中的扩散接口的宽度是薄的相比，其局部曲率半径。结果发现，表面自由能和扩散界面的厚度具有相同的各向异性，而动力学系数具有各向异性，其特征在于由产品的界面厚度与相场的本征迁移率。
The inclusion of anisotropic surface free energy and anisotropic linear interface kinetics in phase-field models is studied for the solidification of a pure material. The formulation is described for a two-dimensional system with a smooth crystal-melt interface and for a surface free energy that varies smoothly with orientation, in which case a quite general dependence of the surface free energy and kinetic coefficient on orientation can be treated; it is assumed that the anisotropy is mild enough that missing orientations do not occur. The method of matched asymptotic expansions is used to recover the appropriate anisotropic form of the Gibbs-Thomson equation in the sharp-interface limit in which the width of the diffuse interface is thin compared to its local radius of curvature. It is found that the surface free energy and the thickness of the diffuse interface have the same anisotropy, whereas the kinetic coefficient has an anisotropy characterized by the product of the interface thickness with the intrinsic mobility of the phase field.