Lu Hongquan, Dong Bin, Zhang Junqian, Lü Chaofeng, Zhan Haifei
College of Civil Engineering and Architecture, Quzhou University, Quzhou 324000, China.
College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China.
Nanomaterials (Basel). 2022 Jun 27;12(13):2203. doi: 10.3390/nano12132203.
Metallic nanowires (NWs) are essential building blocks for flexible electronics, and experience different deformation modes due to external mechanical loading. Using atomistic simulations, this work investigated the deformation behavior of copper nanowire under coupled tension-torsion loading. A transition in both yielding pattern and dislocation pattern were observed with varying torsion/tension strain ratios. Specifically, increasing the torsion/tension strain ratio (with larger torsional strain) triggered the nucleation of different partial dislocations in the slip system. At low torsion/tension strain ratios, plastic deformation of the nanowire was dominated by stacking faults with trailing partial dislocations pinned at the surface, shifting to two partial dislocations with stacking faults as the strain ratio increases. More interestingly, the NW under tension-dominated loading exhibited a stacking fault structure after yielding, whereas torsion-dominated loading resulted in a three-dimensional dislocation network within the structure. This work thus suggests that the deformation behavior of the NW varies depending on the coupled mechanical loading, which could be beneficial for various engineering applications.
金属纳米线（NWs）是柔性电子器件的重要组成部分，并且由于外部机械载荷而经历不同的变形模式。通过原子模拟，这项工作研究了铜纳米线在拉伸-扭转耦合载荷下的变形行为。随着扭转/拉伸应变比的变化，观察到屈服模式和位错模式都发生了转变。具体而言，增加扭转/拉伸应变比（较大的扭转应变）会触发滑移系统中不同部分位错的形核。在低扭转/拉伸应变比下，纳米线的塑性变形以堆垛层错为主导，尾部部分位错固定在表面，随着应变比增加转变为具有堆垛层错的两个部分位错。更有趣的是，在拉伸主导载荷下的纳米线在屈服后呈现出堆垛层错结构，而扭转主导载荷则导致结构内形成三维位错网络。因此，这项工作表明纳米线的变形行为取决于耦合机械载荷，这对各种工程应用可能是有益的。
