Plasticity of metallic nanowires is often controlled by the activities of single deformation mode. It remains largely unclear whether multiple deformation modes can be activated in an individual metallic nanowire and how much plasticity they can contribute. In situ nanomechanical testing reveals a superior plastic deformation ability of body-centered cubic (BCC) niobium nanowires, in which a remarkable elongation of more than 269% is achieved before fracture. This superplastic deformation originates from a synergy of consecutively nucleated multiple reorientation processes that occur for more than five times via three distinct mechanisms, that is, stress-activated phase transformation, deformation twinning, and slip-induced crystal rotation. These three coupled mechanisms work concurrently, resulting in sequential reorientations and therefore superplastic deformation of Nb nanowires. Our findings reveal a superior mechanical property of BCC Nb nanowires through the close coordination of multiple deformation modes, which may have some implications in other metallic nanowire systems.

中文翻译：

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连续晶体学取向和体心立方铌纳米线的超塑性。

金属纳米线的可塑性通常由单一变形模式的活动来控制。在单个金属纳米线中是否可以激活多种变形模式，以及它们可以贡献多少塑性，目前尚不清楚。原位纳米力学测试表明，体心立方（BCC）铌纳米线具有出色的塑性变形能力，其中断裂前可实现超过269％的显着伸长率。这种超塑性变形源自连续成核的多重重新定向过程的协同作用，该过程通过三种不同的机制发生了五次以上，即应力激活的相变，形变孪晶和滑移引起的晶体旋转。这三种耦合的机制可以同时工作，导致顺序重新定向，并因此导致Nb纳米线的超塑性变形。我们的发现通过多种变形模式的紧密配合揭示了BCC Nb纳米线的优异机械性能，这可能对其他金属纳米线系统具有一定的影响。