Cao Hui, Chen Wenke, Rui Zhiyuan, Yan Changfeng
School of Mechanical and Electronical Engineering, Lanzhou University of Technology, Lanzhou 730050, People's Republic of China.
Key Laboratory of Digital Manufacturing Technology and Application, the Ministry of Education, Lanzhou University of Technology, Lanzhou 730050, People's Republic of China.
Nanotechnology. 2022 Jun 15;33(36). doi: 10.1088/1361-6528/ac3e32.
Metal nanomaterials exhibit excellent mechanical properties compared with corresponding bulk materials and have potential applications in various areas. Despite a number of studies of the size effect on Cu nanowires mechanical properties with square cross-sectional, investigations of them in rectangular cross-sectional with various sizes at constant volume are rare, and lack of multifactor coupling effect on mechanical properties and quantitative investigation. In this work, the dependence of mechanical properties and deformation mechanisms of Cu nanowires/nanoplates under tension on cross-sessional area, aspect ratio of cross-sectional coupled with orientation were investigated using molecular dynamics simulations and the semi-empirical expressions related to mechanical properties were proposed. The simulation results show that the Young's modulus and the yield stress sharply increase with the aspect ratio except for the 〈110〉{110}{001} Cu nanowires/nanoplates at the same cross-sectional area. And the Young's modulus increases while the yield stress decreases with the cross-sectional area of Cu nanowires. However, both of them increase with the cross-sectional area of Cu nanoplates. Besides, the Young's modulus increases with the cross-sectional area at all the orientations. The yield stress shows a mildly downward trend except for the 〈111〉 Cu nanowires with increased cross-sectional area. For the Cu nanowires with a small cross-sectional area, the surface force increases with the aspect ratio. In contrast, it decreases with the aspect ratio increase at a large cross-sectional area. At the cross-sectional area of 13.068 nm, the surface force decreases with the aspect ratio of the 〈110〉 Cu nanowires while it increases at other orientations. The surface force is a linearly decreasing function of the cross-sectional area at different orientations. Quantitative studies show that Young's modulus and yield stress to the aspect ratio of the Cu nanowires satisfy exponent relationship. In addition, the main deformation mechanism of Cu nanowires is the nucleation and propagation of partial dislocations while it is the twinning-dominated reorientation for Cu nanoplates.
与相应的块状材料相比，金属纳米材料具有优异的力学性能，并且在各个领域都有潜在的应用。尽管已经有许多关于方形横截面的铜纳米线力学性能尺寸效应的研究，但对于恒定体积下不同尺寸矩形横截面的铜纳米线力学性能的研究却很少，并且缺乏对力学性能的多因素耦合效应和定量研究。在这项工作中，使用分子动力学模拟研究了拉伸状态下铜纳米线/纳米板的力学性能和变形机制对横截面面积、横截面纵横比以及取向的依赖性，并提出了与力学性能相关的半经验表达式。模拟结果表明，在相同横截面面积下，除了〈110〉{110}{001}铜纳米线/纳米板外，杨氏模量和屈服应力随纵横比急剧增加。铜纳米线的杨氏模量随横截面面积增加而增大，屈服应力则减小。然而，对于铜纳米板，两者均随横截面面积增加而增大。此外，在所有取向下，杨氏模量都随横截面面积增加而增大。屈服应力除了〈111〉铜纳米线随横截面面积增加呈轻微下降趋势外，其他情况呈下降趋势。对于横截面面积较小的铜纳米线，表面力随纵横比增加而增大。相反，在横截面面积较大时，表面力随纵横比增加而减小。在横截面面积为13.068 nm时，〈110〉铜纳米线的表面力随纵横比减小，而在其他取向则增大。在不同取向下，表面力是横截面面积的线性递减函数。定量研究表明，铜纳米线的杨氏模量和屈服应力与纵横比满足指数关系。此外，铜纳米线的主要变形机制是部分位错的形核和扩展，而铜纳米板的主要变形机制是以孪晶为主的重取向。
