Atomic structure insight into crystallization of undercooled liquid metal Zr during isothermal relaxation processes
Atomic structure insight into crystallization of undercooled liquid metal Zr during isothermal relaxation processes
复制标题
等温弛豫过程中过冷液态金属 Zr 结晶的原子结构洞察
DOI：
10.1080/14786435.2019.1644464
复制
发表时间：
2019-07
影响因子：
1.6
通讯作者：
Peng Ping
中科院分区：
文献类型：
--
作者：
Wen Dadong;Deng Yonghe;Dai Xiongying;Tian Zean;Peng Ping
摘要采用分子动力学模拟方法研究了过冷液态锆的结晶过程。通过对分布函数、角分布函数和最大标准聚类分析对原子结构进行了表征和分析。在低温下（T = 1000 K），结晶开始于弛豫初期，结晶路径为过冷液相（UCL）→BCC→HCP，而不是UCL→HCP。 HCP型中程有序（MRO）是从BCC型MRO形成的前驱体内部形成的，并且以前驱体为代价生长，符合Ostwald阶梯规则。发现在该过程中，MRO的数量在形成晶相中起关键作用。然而，在高温（T = 1200 K）下，达到结晶的时间尺度比T = 1000 K时大两个数量级。 没有观察到结晶的中间阶段。过冷Zr熔体直接转变为BCC晶相。BCC-MRO的最大尺寸与结晶密切相关。
ABSTRACT The crystallization of undercooled liquid zirconium (Zr) was investigated via molecular dynamics simulations. The atomic structures were characterised and analysed by means of pair distribution function, angular distribution function, and the largest standard cluster analysis. At low temperature (T = 1000 K), it is found that the crystallization begins at the initial stage of relaxation and takes the pathway of undercooled liquid (UCL)→BCC→HCP instead of UCL→HCP. The HCP-type medium-range orders (MROs) are formed from the inside of the precursors formed by the BCC-type MROs, and growing at the cost of the precursors, in agreement with the Ostwald’s step rule. The number of MROs is found to play a key role in forming the crystal phases in this process. However, at high temperature (T = 1200 K) the time-scale to reach crystallization is two orders of magnitude bigger than that of T = 1000 K. No intermediate stage of crystallization is observed. The undercooled Zr melts are directly transformed into BCC crystal phases. The max size of BCC-MROs is intimately correlated with the crystallization.
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影响因子：
3.3
作者：
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影响因子：
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作者：
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影响因子：
3
作者：
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DOI：
10.1063/1.4792067
发表时间：
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期刊：
The Journal of chemical physics
影响因子：
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通讯作者：
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