计算物理

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Al纳米线不同晶向力学行为和变形机制的模拟研究

侯兆阳 牛媛 肖启鑫 王真 邓庆田   

  1. 长安大学理学院 西安 710064

  • 收稿日期:2021-08-12 修回日期:2021-08-27 接受日期:2021-08-27 出版日期:2021-10-14 发布日期:2021-10-14
  • 基金资助:
    国家自然科学基金资助项目(50831003)

Simulation Study of Mechanical Behavior and Deformation Mechanism of Al Nanowire along Different Crystal Orientations

HOU Zhaoyang,  NIU Yuan,  XIAO Qixin  WANG Zhen  DENG Qingtian   

  1. School of Science, Chang’an University, Xi’an 710064, China
  • Received:2021-08-12 Revised:2021-08-27 Accepted:2021-08-27 Online:2021-10-14 Published:2021-10-14

摘要: 金属纳米线的力学行为是影响其应用的重要指标之一,而具有较高层错能的Al纳米线往往呈现出与其它FCC金属纳米线不同的变形机制。本文采用分子动力学模拟计算的方法,考察了具有较高层错能的Al纳米线沿不同晶向的力学行为和变形机制,同时在计算条件下与具有较低层错能的Ni、Cu、Au和Ag等FCC金属纳米线进行了比较。结果表明:在力学行为方面,Al纳米线的弹性模量呈现明显的结构各向异性,满足E[111]>E[110]>E[100]的关系,这一关系在其它FCC金属纳米线中普遍成立;Al纳米线的屈服应力随晶向呈现σy[100]>σy[111]>σy[110]的关系,这一关系在其它具有较低层错能的FCC金属纳米线中不具有普遍性,这与体系中位错形成机制密切相关。进一步,根据拉伸变形过程微观结构的演变规律,阐明了Al纳米线不同晶向的变形机制,并与其它具有较低层错能的Ni、Cu、Au和Ag等FCC金属纳米线的变形机制进行了比较。结果还表明,对于尺度较小的高层错能Al纳米线,Schmid因子和广义层错能均难以准确预测其变形机制。

关键词: Al纳米线, 变形机制, 晶向, 分子动力学模拟

Abstract: The mechanical behavior is an important factor that affect its application, and the Al nanowire with high stacking fault energy usually displays different deformation mechanisms comparing with other FCC metal nanowires. Thus, the mechanical behavior and deformation mechanism of Al nanowire along different crystal orientations are investigated by molecular dynamics simulation, and they are compared with other FCC metal nanowires with lower fault energy such as Ni, Cu, Au and Ag under the same computational conditions. It is found that the elastic module of Al nanowire along different crystal orientations displays the relationship of E[111]>E[110]>E[100], which is generally true in other FCC nanowires. The yield stress of Al nanowire along different crystal orientations displays the relationship of σy[100]>σy[111]>σy[110], which is not generally true in other FCC nanowires. Furthermore, the deformation mechanism of Al nanowire along crystal orientations is clarified according to the evolution of microstructures. And it is compared with the nanowires of Ni, Cu, Au and Ag. It is also found that it difficult to predict the deformation mechanism accurately by the Schmid factor and the stacking fault energy for Al nanowire with high fault energy in such small scale.

Key words: Al nanowire, deformation mechanism, crystal orientations, molecular dynamics simulation

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