高等学校化学学报 ›› 2018, Vol. 39 ›› Issue (3): 514-520.doi: 10.7503/cjcu20170496

• 物理化学 • 上一篇    下一篇

金属纳米线中凸凹微结构对初始形变的影响

李韧1, 赵健伟1,2(), 侯进1(), 贺园园2, 程娜2   

  1. 1. 西南交通大学信息科学与技术学院, 成都 610031
    2. 嘉兴学院材料与纺织工程学院, 嘉兴 314001
  • 收稿日期:2017-07-21 出版日期:2018-03-10 发布日期:2018-01-15
  • 作者简介:联系人简介: 赵健伟, 男, 博士, 教授, 博士生导师, 主要从事有机分子和二维材料的电子输运研究. E-mail:jwzhao@mail.zjxu.edu.cn;侯 进, 女, 博士, 副教授, 主要从事计算机图形学与深度学习研究. E-mail:jhou@swjtu.edu.cn
  • 基金资助:
    国家自然科学基金(批准号: 21273113)资助

Effect of the Convex and the Concave Microstructures in the Metallic Nanowires on the Initial Deformation Behavior

LI Ren1, ZHAO Jianwei1,2,*(), HOU Jin1,*(), HE Yuanyuan2, CHENG Na2   

  1. 1. Southwest Jiaotong University, School of Information Science and Technology, Chengdu 610031, China
    2. Jiaxing University, College of Materials and Textile Engineering, Jiaxing 314001, China
  • Received:2017-07-21 Online:2018-03-10 Published:2018-01-15
  • Contact: ZHAO Jianwei,HOU Jin E-mail:jwzhao@mail.zjxu.edu.cn;jhou@swjtu.edu.cn
  • Supported by:
    † Supported by the National Natural Science Foundation of China(No.21273113)

摘要:

构建了具有代表性的系列凸纳米线和凹纳米线, 利用分子动力学模拟研究了2种微结构对拉伸形变的影响. 结果表明, 微凸纳米线与单晶纳米线表现出类似的行为, 其能量和应力应变曲线等均无显著差异. 改变不同的凸起高度未发现显著差别. 沿z轴的应力分布分析表明凸微结构使局域应力降低, 不能诱导产生初始位错滑移; 微凹纳米线表现更明显的塑性形变特征, 小应变时能量上升的幅度低于单晶和凸纳米线, 但大应变条件下能量上升更高, 微凹纳米线的第一屈服点早于单晶和凸纳米线, 且其屈服应力不是最大应力, 沿z轴的应力分布表明凹陷处产生增加的局域应力, 凹陷附近可以诱导产生初始位错滑移. 原子排布位图从微观上进一步阐述了上述形变特征.

关键词: 金属纳米线, 纳米结构, 应力应变, 纳米拉伸, 分子动力学

Abstract:

A series of simplified nanowires with specific convex and concave nanostructures was modelled and investigated via molecular dynamics simulations. The tensile speed was as low as 0.0758%/ps, allowing the nanowire system keeping in an equilibrium stretching state. The deformation behavior had been compared with the single crystal nanowire as well. The results demonstrate that the convex nanowire has the similar deformation behavior as the single crystal nanowire does, showing a coincident evolution of the potential and stress-strain curves. Although the stress distribution along the z-axis exhibits a decrease around the convex nanostructure, it cannot induce any initial dislocation and slip. On the contrary, the concave nanowire possesses plastic character rather than the elastic one. When the strain is less then 0.03, the potential energy of the concave nanowire increases slower than the convex and the single crystal nanowires do. However, this behavior becomes the reverse when the strain is larger than this value. In addition, the first yield point comes earlier than the maximum stress for the concave nanowire. The stress distribution along the z-axis presents an increased stress around the concave nanostructure. Therefore, the first dislocations are generated near to the concave nanostructure. The analysis of the atomic arrangement further confirms this explanation.

Key words: Metallic nanowires, Nanostructure, Stress-strain, Nano-stretching, Molecular dynamics

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