金属学报  2012, Vol. 48 Issue (1): 41-48    DOI: 10.3724/SP.J.1037.2011.00457

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定向凝固共晶生长的元胞自动机数值模拟

石玉峰, 许庆彦, 柳百成

清华大学机械工程系先进成形制造教育部重点实验室, 北京 100084

SIMULATION OF EUTECTIC GROWTH IN DIRECTIONAL SOLIDIFICATION BY CELLULAR AUTOMATON METHOD

SHI Yufeng, XU Qingyan, LIU Baicheng

Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanical Engineering, Tsinghua University, Beijing 100084

石玉峰 许庆彦 柳百成. 定向凝固共晶生长的元胞自动机数值模拟[J]. 金属学报, 2012, 48(1): 41-48.
, , . SIMULATION OF EUTECTIC GROWTH IN DIRECTIONAL SOLIDIFICATION BY CELLULAR AUTOMATON METHOD[J]. Acta Metall Sin, 2012, 48(1): 41-48.

摘要 参考文献 相关文章 Metrics 全文: PDF(1963 KB)   摘要: 本文在已有的二元初生相元胞自动机(CA)方法的基础上, 针对二元共晶凝固过程提出了改进的元胞自动机(MCA)模型. 该模型考虑成分过冷和曲率过冷对界面形态的影响, 通过界面溶质浓度守恒来获得共晶α相和β相生长速率, 模拟了层片的湮灭、分叉与稳态生长. 为了验证模型的可靠性, 对常见的 CBr4-C2Cl6共晶透明合金进行了模拟, 研究了抽拉速率对共晶层片间距大小的影响, 模拟结果与文献中的实验结果吻合良好; 同时模拟了共晶层片间距调整过程的形貌演化以及层片振荡不稳定性现象. 本文将 MCA模型扩展到三维定向凝固过程中, 研究了共晶形态的层--棒状转变机制. 关键词 ： 改进的元胞自动机,  共晶层片稳定性,  振荡不稳定性,  层-棒状转变     Abstract：Eutectic microstructures are one of the most common solidification patterns in the binary or multi-component alloy systems. Due to the fine periodic microstructures of the eutectic alloys, the commercial applications of the eutectic alloys can improve the mechanical properties of the castings. The solidification mechanism of eutectic alloys has been widely studied by a lot of experimental works and theoretical analysis over the years. Recently, numerical models were used to study the mechanisms of formation of phase patterns and selection dynamics of the lamellar eutectic, such as phase field (PF) and cellular automaton (CA) model, which can promote the development of eutectic growth theory. Based on the existing CA method for binary primary α phase, a modified cellular automaton (MCA) model was developed for the simulation of binary eutectic growth. In this model, the influence of constitutional and curvature undercooling on the interface morphology was considered. The growth rate of eutectic interface was calculated by the solute conservation at the $\alpha$/liquid and $\beta$/liquid interfaces. The model could simulate the phenomenon of overgrowth, splitting and steady state growth of the eutectic lamellar. CBr4-C2Cl6 eutectic transparent alloy was chosen to validate the model. The simulated results showed that the increasing pulling rate lead to a smaller eutectic lamellar spacing, which had a good agreement with the Jackson--Hunt theory and the experimental results from the literature. Eutectic morphology evolution was simulated under a constant pulling rate and temperature gradient, which showed that the stable lamellar structures existed when the initial lamellar spacing was in a finite range between the minimum stable spacing λm and the limiting maximum stable spacing λm. A smaller initial lamellar spacing would lead to lamellar annihilation. Conversely, a larger initial lamellar spacing could lead to the lamellar nucleation due to the appearance of solute rich concave at the center of the α/liquid interface. Meanwhile, the oscillatory instability of the eutectic lamellar was also reappeared by the MCA model. The MCA model was easily extended to 3D, and the lamellar-rod transition during directional solidification was simulated, which showed that the ratio of volume fraction of α and β phase was smaller than 1/Π tend to form lamellar-rod transition when the initial lamellar spacing was smaller than λm. Key words： modified cellular automaton    eutectic lamellar stability    oscillatory instability    lamellar-rod transition 收稿日期: 2011-07-18      ZTFLH:  O781   基金资助: 国家重点基础研究发展计划项目2005CB724105和2011CB706801, 国家自然科学基金项目10477010和51171089, 国家高技术研究发展计划项目2007AA04Z141及国家科技重大专项项目2009ZX04006-041-04和2011ZX04014-052资助 作者简介: 石玉峰, 男, 1985年生, 博士生 服务 把本文推荐给朋友 加入引用管理器 E-mail Alert RSS 作者相关文章 石玉峰 许庆彦 柳百成 44.8K 链接本文: https://www.ams.org.cn/CN/10.3724/SP.J.1037.2011.00457      或      https://www.ams.org.cn/CN/Y2012/V48/I1/41 [1] Aguiar M R, Caram R. J Cryst Growth, 1996; 166: 398 [2] C¸adirli E, Kaya H, G¨und¨uz M. J Alloys Compd, 2007; 431: 171 [3] Ginibre M, Akamatsu S, Faivre G. 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