Crystallization of Lennard-Jones liquids under dynamic compression: Heterogeneous and homogeneous nucleation.
Crystallization of Lennard-Jones liquids under dynamic compression: Heterogeneous and homogeneous nucleation.
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DOI：
10.1063/1.5010088
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发表时间：
2017-12
期刊：
影响因子：
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通讯作者：
J. Cai;J. E;M. Tang;X. Zhu;Y. Cai;S. Luo
中科院分区：
文献类型：
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作者：
J. Cai;J. E;M. Tang;X. Zhu;Y. Cai;S. Luo
我们用大规模的分子动力学模拟研究了动态压缩下Lennard-Jones液体在衬底上的结晶。所研究的衬底包括具有不同晶向的单晶和双晶，加载路径包括冲击加载和准等熵加载。用模拟X射线衍射仪和取向图对其微观结构进行了表征。对于冲击加载，只有非均相成核发生在模拟尺度上。准等熵加载导致较少的加热和较大的过冷度；结果是，尽管衬底是结晶的，但在低加载强度下，非均质成核发生，而在高加载强度下，非均质成核和均匀成核都发生。晶化取决于衬底结构(晶体取向和晶界)和加载特性。变形可能会导致基片的晶粒结构变化(例如，重新取向和孪晶)，并影响后续的结晶。晶化速率是各向异性的，与衬底平面和主{111}生长面之间的二面角的余弦成反比。
We investigate crystallization of Lennard-Jones liquids on substrates under dynamic compression with large-scale molecular dynamics simulations. The substrates examined include single crystals and bicrystals with different crystallographic orientations, and the loading paths include shock and quasi-isentropic loading. Microstructure is characterized with simulated x-ray diffraction and orientation mapping. For shock loading, only heterogeneous nucleation occurs at the simulation scales. Quasi-isentropic loading induces less heating and larger supercooling; as a result, heterogeneous nucleation occurs at low loading strengths, and both heterogeneous and homogeneous nucleation occur at high loading strengths, despite the crystalline substrates. Crystallization depends on the substrate structure (crystal orientation and grain boundary) and loading characteristics. Deformation may induce grain structure change (e.g., reorientation and twinning) of substrates and affect subsequent crystallization. Crystallization rate is anisotropic, inversely proportional to the cosine of the dihedral angle between the substrate plane and a main {111} growth plane.