Limitations of preserving volume in Allen-Cahn framework for microstructural analysis
Limitations of preserving volume in Allen-Cahn framework for microstructural analysis
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DOI：
10.1016/j.commatsci.2019.109388
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发表时间：
2020-02-15
影响因子：
3.3
通讯作者：
Nestler, Britta
中科院分区：
文献类型：
--
作者：
Amos, P. G. Kubendran;Schoof, Ephraim;Nestler, Britta
在Allen-Cahn框架中保持体积是Cahn-Hilliard方法的一种计算效率高的替代方法。本文揭示了采用保体积Allen-Cahn方法分析化学平衡中曲率驱动的形态学变化的局限性。比较了Allen-Cahn框架下的能量再分配方法和包含守恒变量的广义准Allen-Cahn（qAC）方法的结果，阐明了前者的局限性.对二维和三维典型微观结构演化的分析表明，Allen-Cahn形式化中的保体积导致相变机制和最终相分布不准确，与实验观察和理论预测有很大偏差。此外，它示出的再分配能量技术，在其现有的形式，未能恢复施加在系统上的热力学条件。
Preserving volume in the Allen-Cahn framework is appealing as a computationally-efficient alternate for Cahn-Hilliard approach. The limitations of adopting volume-preserved Allen-Cahn treatment to analyse curvature-driven morphological transformations in chemical equilibrium is unraveled in the present work. The outcomes of redistribution-energy technique, which operates in Allen-Cahn framework, and a thermodynamically-consistent generalised quasi-Allen-Cahn (qAC) treatment, involving a conserved variable, is comparatively studied to explicate the limitations of the former. Analysis of representative microstructural evolution, in two- and three-dimension, indicates that preserving volume in Allen-Cahn formalism renders an inaccurate transformation mechanism and final phase-distribution, which significantly deviate from the experimental observations and theoretical predictions. Moreover, it is shown that the redistribution-energy technique, in its existing form, fails to recover the thermodynamic condition imposed on the system.