Tailoring mechanical properties of the nanowire (NW) with intricate composite structure helps to design nanodevices with novel functionalities. Here, we performed in situ tensile deformation electron microscopy for the evaluation of the mechanical properties of the focused ion beam (FIB) irradiated silicon nitride (Si₃N₄) nanowires (NWs). Young’s modulus of the FIB-fabricated NWs was mediated between the range of 522 and 65 GPa by modifying the shell thickness of the core–shell structure. The ion-beam-induced amorphization is found to induce the structural transition from an utter crystalline state to a composite NW with an amorphous shell, which results in a brittle-to-ductile transition and an unexpected plastic deformation. These results have practical implications for optimizing nanostructures with the desired mechanical properties, which are of fundamental relevance in designing and fabricating nanomechanical devices.

中文翻译：

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聚焦离子束辐照诱导氮化硅纳米线的可调力学性能和结构转变。

定制具有复杂复合结构的纳米线（NW）的机械性能有助于设计具有新颖功能的纳米器件。在这里，我们进行了原位拉伸变形电子显微镜，以评估聚焦离子束（FIB）辐照的氮化硅（Si ₃ N ₄纳米线（NWs）。通过改变核-壳结构的壳厚度，FIB制造的NW的杨氏模量介于522和65 GPa之间。发现离子束诱导的非晶化诱导了从完全结晶态到具有非晶态壳的复合NW的结构转变，这导致了脆性到韧性的转变以及意外的塑性变形。这些结果对于优化具有所需机械性能的纳米结构具有实际意义，这对设计和制造纳米机械装置具有根本意义。