中文摘要：

本文利用自创的热双金属片拉伸装置实现了在透射电镜中,对单晶Mo纳米线的原位拉伸实验。实验发现单晶Mo纳米线具有块体单晶材料2倍左右的塑性变形能力。观察发现变形过程中位错不断的形核产生、然后快速的运动并消失在纳米线表面是单晶Mo纳米线具有大塑性变形能力的一个重要原因。另外,利用选区电子衍射对拉伸断裂后的样品分析,发现拉伸后的纳米线的断口附近呈现多晶化。可以认为在高应变作用下,位错的滑移等因素导致单晶点阵局部扭转形成小角度晶界,纳米线局部从单晶转变成多晶。

英文摘要：

Using a homemade bi-metallic extensor,the in-situ tensile experiments of Mo nanowire was conducted in a transmission electron microscope. We demonstrate that the Mo nanowire exhibit ultra-large plastic deformation ability,which is about twice as much as its bulk counterpart. The dislocation nucleation,motion and escaping are responsible for the ultra-large strain ability. In addition,the selected area electron diffraction patterns indicated deformation can lead to single-crystal to poly-crystal transformation near the fracture,which was rarely seen in previous. Under high stress,the local crystal lattice distortion,dislocation slip etc. lead to singlecrystal to poly-crystal transformation.