物理化学学报 >> 2013, Vol. 29 >> Issue (02): 245-249.doi: 10.3866/PKU.WHXB201212251

理论与计算化学 上一篇    下一篇

嵌入纳米Fe颗粒的Fe液凝固过程的分子动力学模拟

吴永全, 沈通, 陆秀明, 张宁, 赖莉珊, 高帅   

  1. 上海大学材料科学与工程学院, 上海市现代冶金及材料制备重点实验室, 上海200072
  • 收稿日期:2012-12-03 修回日期:2012-12-25 发布日期:2013-01-14
  • 通讯作者: 吴永全 E-mail:yqwu@shu.edu.cn
  • 基金资助:

    国家重点基础研究发展计划(973)(2012CB722805);国家自然科学基金(50504010, 50974083, 51174131);国家自然科学基金钢铁联合基金(50774112);上海市青年科技启明星计划(07QA4021)资助项目

Solidification of Liquid Fe with Embedded Homogeneous Solid Fe Nanoparticles from Molecular Dynamics Simulations

WU Yong-Quan, SHEN Tong, LU Xiu-Ming, ZHANG Ning, LAI Li-Shan, GAO Shuai   

  1. Solidification processes of liquid Fe with embedded homogeneous solid nanoparticle with radius ranging from 0.4 to 1.8 nm were studied by molecular dynamics (MD) simulation adopting the Sutton-Chen potential. It was found that the particles whose radii exceed 0.82 nm could obviously decrease the critical undercooling (ΔT*) and induce solidification. The microstructural evolution during the solidification process was traced through the atom definition with cluster-type index method (CTIM-2). Results revealed that when the embedded particle induced solidification, the growth process of nucleus would proceed as a cross-nucleation between hcp and fcc structures, a little similar to the eutectic crystallization process. Moreover, the heredity effect attributed by embedded solid nanoparticle was clearly observed during the microstructural evolution.
  • Received:2012-12-03 Revised:2012-12-25 Published:2013-01-14
  • Supported by:

    The project was supported by the National Key Basic Research Program of China (973) (2012CB722805), National Natural Science Foundation of China (50504010, 50974083, 51174131), Joint Funds of ational Natural Science Foundation of China-Steel, China (50774112), Shanghai “Phosphor” Science Foundation, China (07QA4021 ).

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摘要：

采用Sutton-Chen 势函数及分子动力学(MD)方法对嵌入了Fe纳米团簇(半径从0.4-1.8 nm)的Fe液凝固过程进行了模拟. 模拟结果表明只有当嵌入的纳米团簇半径超过0.82 nm才能降低凝固时所需要的临界过冷度(ΔT*), 起到诱导凝固的作用. 同时采用原子键型指数法(CTIM-2)对样本在凝固过程中的原子结构进行了标定, 通过观察微观结构演变发现当嵌入纳米团簇能够作为凝固核心时, 体系按照hcp-fcc 交叉形核的方式长大. 同时还发现嵌入纳米团簇对体系凝固过程晶核的生长方向及凝固的最终构型存在“结构遗传效应”.

关键词: Fe纳米团簇, 过冷度, 凝固过程, 微观结构演化, 分子动力学

Abstract:

Solidification processes of liquid Fe with embedded homogeneous solid nanoparticle whose radius ranges from 0.4 to 1.8 nm have been studied by molecular dynamics simulation adopting the Sutton-Chen potential. It was found that the particles whose radii exceed 0.82 nm can obviously decrease the critical undercooling (ΔT*) and induce solidification. The microstructural evolution during the solidification process is traced through the atom definition with cluster-type index method (CTIM-2). Results revealed that when the embedded particle induced solidification, the growth process of nucleus would proceed as a cross-nucleation between hcp and fcc structures, a little similar to the eutectic crystallization process. Moreover, the heredity effect attributed by embedded solid nanoparticle is clearly observed during the microstructural evolution.

Key words: Solid Fe nanoparticle, Undercooling, Solidification process, Microstructural evolution, Molecular dynamics simulation