Large-scale phase-field study of anisotropic grain growth: Effects of misorientation-dependent grain boundary energy and mobility
Large-scale phase-field study of anisotropic grain growth: Effects of misorientation-dependent grain boundary energy and mobility
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DOI：
10.1016/j.commatsci.2020.109992
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发表时间：
2021
影响因子：
3.3
通讯作者：
Eisuke Miyoshi;T. Takaki;S. Sakane;M. Ohno;Y. Shibuta;T. Aoki
中科院分区：
文献类型：
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作者：
Eisuke Miyoshi;T. Takaki;S. Sakane;M. Ohno;Y. Shibuta;T. Aoki
通过相场模拟研究了各向异性（取向差相关）晶界能和迁移率下的三维晶粒生长行为。基于多相场模型和超级计算机上的并行图形处理单元计算，实现了超过300万个晶粒的超大规模模拟，从而能够对各向异性晶粒生长进行可靠的统计评估。通过经典的Read-Shockley模型和S形模型引入各向异性边界性质，并将这些模型中包含的阈值取向差角Δθh作为确定系统各向异性强度的量。对不同的Δθ h值进行了系统的模拟，研究了各向异性强度与晶粒尺寸和取向差分布等晶粒生长特性之间的关系。结果表明，各向异性晶粒长大达到稳态区与Δθ h值无关。然而，在稳态生长过程中的动力学和微观结构形态在很大程度上取决于Δθh。此外，通过与模拟结果的比较，验证了晶粒长大解析理论对各向异性体系的适用性。实验结果表明，现有理论不能很好地描述各向异性生长中的稳态微结构，这可能是因为理论的基本假设不适用于各向异性系统。
Three-dimensional grain growth behaviors under anisotropic (misorientation-dependent) grain boundary energy and mobility are investigated via phase-field simulations. Based on a multi-phase-field model and parallel graphics-processing unit computing on a supercomputer, very large-scale simulations with more than three million grains are achieved, enabling reliable statistical evaluation of anisotropic grain growth. The anisotropic boundary properties are introduced by the classical Read-Shockley and sigmoidal models; the threshold misorientation angle, Δθh, included in these models is used as a quantity to determine the anisotropy strength of the system. Systematic simulations are performed for different Δθhvalues, through which the correlations between the anisotropy strength and grain growth characteristics such as grain size and misorientation distributions are examined. The obtained results show that anisotropic grain growth reaches the steady-state regime irrespective of the Δθhvalue. However, the kinetics and microstructural morphology during the steady-state growth are largely dependent on Δθh. Furthermore, by comparison with the simulated results, the applicability of analytical grain growth theories to anisotropic systems are tested. The tests reveal that the steady-state microstructure in anisotropic growth cannot be well captured by the existing theories, which is likely because the basic assumptions of the theories do not hold for anisotropic systems.