华东师范大学学报(自然科学版) ›› 2024, Vol. 2024 ›› Issue (3): 54-63.doi: 10.3969/j.issn.1000-5641.2024.03.006

• 第一性原理计算 • 上一篇    下一篇

异质固液界面中多界面态的原子模拟研究

刘娇娇, 梁洪涛, 杨洋*()   

  1. 华东师范大学 物理与电子科学学院 凝聚态物理研究所, 上海 200241
  • 收稿日期:2023-09-19 出版日期:2024-05-25 发布日期:2024-05-25
  • 通讯作者: 杨洋 E-mail:yyang@phy.ecnu.edu.cn
  • 基金资助:
    国家自然科学基金(11874147); 上海市自然科学基金(23ZR1420200)

Research on atomistic simulation of the coexistence of multiple interfacial states at heterogeneous solid-liquid interface

Jiaojiao LIU, Hongtao LIANG, Yang YANG*()   

  1. Institute of Condensed Matter Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
  • Received:2023-09-19 Online:2024-05-25 Published:2024-05-25
  • Contact: Yang YANG E-mail:yyang@phy.ecnu.edu.cn

摘要:

在晶界和固体表面系统中, 针对界面“complexion” (或界面相、界面态) 转变及其调控相关的研究, 近年来呈现出持续增长的关注趋势. 与此同时, 这些界面相之间的转变问题, 在异质固液界面体系中尚未得到足够的关注. 使用分子动力学模拟方法预言了处于Pb熔点温度之上, Cu(111)/Pb(L)固液界面体系中存在的多界面相共存的界面状态; 观察到4种单原子层的界面状态, 即2种界面CuPb层状合金液相以及2种界面预凝固的Pb层状固相, 共存于固体Cu和液体Pb之间的双原子界面层内; 通过计算界面相在面内共存的各种性质空间分布, 模拟出了该体系多界面相共存的力学、热力学和动力学性质的不均匀性和面内各向异性; 计算获得的界面态热力学与动力学性质数值显著区别于固相Cu和液相Pb的相应性质. 另外, 测量得到的Cu(111)/Pb(L)固液界面态共存的“相平衡”条件具有共晶二元合金相图特征, 而不是CuPb合金的偏晶相图. 故所报道的数据有望为调节异质形核和润湿过程提供新的理论思路.

关键词: 异质合金, 固液界面, 预凝固相变, 界面相图, 分子动力学

Abstract:

Engineering interfacial complexion (or phase) transitions has been a growing trend in grain boundary and solid surface systems. In addition, little attention has been paid to chemically heterogeneous solid-liquid interfaces. In this study, atomistic simulations are conducted to reveal the coexistence of novel in-plane multi-interfacial states in a Cu(111)/Pb(L) interface at a temperature just above the Pb freezing point. Four monolayer interfacial states, that is, two CuPb alloy liquids and two pre freezing Pb solids, are observed to coexist within two interfacial layers sandwiched between the bulk solid Cu and bulk liquid Pb. Computation of the spatial variations of various properties along the direction normal to the in-plane solid-liquid boundary lines for both interfacial layers presents a rich and varied picture of inhomogeneity and anisotropy in the mechanical, thermodynamical, and dynamical properties. The “bulk” values extracted from the in-plane profiles suggest that each interfacial state examined has distinct equilibrium values and significantly deviates from those of the bulk solid and liquid phases. It also indicates that the “complexion (or phase) diagrams” for the Cu(111)/Pb(L) interface bear a resemblance to those of the eutectic binary alloy systems as opposed to the monotectic phase diagram for the bulk CuPb alloy. The reported data supports the development of interfacial complexion (or phase) diagrams and interfacial phase rules and provides new guidelines for regulating heterogeneous nucleation and wetting processes.

Key words: heterogeneous alloy, solid-liquid interface, prefreezing transition, interfacial phase diagram, molecular dynamics

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