npj Computational Materials

Ultra-large-scale phase-field simulation study of ideal grain growth (理想晶粒生长的超大规模相场模拟研究)
Eisuke Miyoshi, Tomohiro Takaki, Munekazu Ohno, Yasushi Shibuta, Shinji Sakane, Takashi Shimokawabe & Takayuki Aoki
npj Computational Materials 3:25 (2017)
doi:10.1038/s41524-017-0029-8
Published online:03 July 2017
Abstract| Full Text | PDF OPEN

摘要: 晶粒生长，是伴随曲率驱动边界迁移的竞争性生长，是冶金学及其他相关学科中最重要的现象之一。然而，即使是最简单、最“理想”的晶粒生长，其真实物理图像也还是争议不断，要解决这个问题非通过大规模数值模拟不可。本研究通过超大规模相场模拟分析了理想晶粒的生长，阐明了相应的真实的统计行为。所进行的数值模拟在时空尺度上比之前所谓最大规模的模拟还要大十倍以上，通过对统计学数量足够多晶粒大规模模拟，强有力展示晶粒的真实、稳态生长行为。此外，我们对理想晶粒生长行为进行全面理论分析，并进行了相关定量化。本研究为理想晶粒生长提供了结论性理解，为研究真实晶粒生长过程奠定基础。　　

Abstract: Grain growth, a competitive growth of crystal grains accompanied by curvature-driven boundary migration, is one of the most fundamental phenomena in the context of metallurgy and other scientific disciplines. However, the true picture of grain growth is still controversial, even for the simplest (or ‘ideal’) case.This problem can be addressed only by large-scale numerical simulation. Here, we analyze ideal grain growth via ultra-large-scale phase-field simulations on a supercomputer for elucidating the corresponding authentic statistical behaviors. The performed simulations are more than ten times larger in time and space than the ones previously considered as the largest; this computational scale gives a strong indication of the achievement of true steady-state growth with statistically sufficient number of grains. Moreover, we provide a comprehensive theoretical description of ideal grain growth behaviors correctly quantified by the present simulations. Our findings provide conclusive knowledge on ideal grain growth, establishing a platform for studying more realistic growth processes.

Editorial Summary

Grain growth: Simulations elucidate statistical behavior (晶粒生长：计算模拟阐明了其统计行为)

本研究采用超大时空尺度的相场计算，模拟理想条件下的晶粒生长，以便阐明晶粒生长的统计行为。来自日本京都理工大学的Tomohiro Takaki及其团队对理想条件下的晶粒生长行为进行了大规模的相场模拟。模拟中所用的时空尺度比之前报道的尺度要大10倍以上，以足够多的晶粒数量确保了统计学意义，使这些模拟能够达到真正的稳态近似。基于模拟结果导出了一个全面理论解释，用来理解理想晶粒的生长行为。这些研究结果为理解真实材料复杂影响因素提供一个理论模型，从而为研究真实晶粒生长过程奠定基础。

Grain growth under ideal conditions is simulated by phase-field simulations in ultra-large time and space scales to elucidate the statistical behaviors. A team led by Tomohiro Takaki at Kyoto Institute of Technology in Japan performed large scale phase-field simulations to study ideal grain growth behavior. The time and space scales used in the simulations are more than ten times larger than those in previous reports, enabling them to reach a true steady-state with a statistically significant number of grains. A comprehensive theoretical description was derived to understand the ideal grain growth behavior based on the simulations. The knowledge provided by these findings may offer a model to understand the effects of complicated factors present in real materials and thus establish a platform to study more realistic grain growth phenomena in the future.