Abstract Reducing the size of metallic glasses (MG) to submicron or nanoscale levels improves their strength and ductility. However, there is no clear consensus in the literature regarding their mechanical behavior in the presence of a flaw or notch. In this work, quantitative tensile tests on notched submicron sized CuZr MG specimens were conducted inside a transmission electron microscope to study their deformation characteristics. Strength was found to be notch insensitive for shallow notched thick specimens, although reducing specimen dimensions and increasing notch sharpness enhances it by 14%. It was reasoned that the severity with which shear bands are geometrically constrained determines the strength and fracture morphology of notched specimens. Softening, accompanied with a transition to necking failure, occurs when the width of ligament that connects the notches is smaller than 80 nm. The competition between shear band propagation and plastic zone growth-mediated homogeneous activation of shear transformation zones was found to be responsible for this brittle to ductile transition. Current results provide unique insights into the various design aspects to be considered for reliable engineering of small scale components.

中文翻译：

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缺口对亚微米尺寸金属玻璃变形行为的影响：原位实验的见解

摘要 将金属玻璃 (MG) 的尺寸减小到亚微米或纳米级可提高其强度和延展性。然而，关于它们在存在缺陷或缺口时的机械行为，文献中没有明确的共识。在这项工作中，在透射电子显微镜内对缺口亚微米尺寸的 CuZr MG 试样进行定量拉伸试验，以研究它们的变形特性。发现对于浅缺口厚试样，强度对缺口不敏感，尽管减小试样尺寸和增加缺口锐度将其提高 14%。原因是剪切带几何约束的严重程度决定了缺口试样的强度和断裂形态。软化，伴随着向颈缩失败的过渡，当连接凹槽的韧带宽度小于 80 nm 时发生。剪切带传播和塑性区生长介导的剪切转变区的均匀激活之间的竞争被发现是造成这种脆性向韧性转变的原因。当前的结果为小型组件的可靠工程需要考虑的各种设计方面提供了独特的见解。