Shear-band thickness and shear-band cavities in a Zr-based metallic glass
Shear-band thickness and shear-band cavities in a Zr-based metallic glass
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DOI：
10.1016/j.actamat.2017.08.032
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发表时间：
2017-11-01
期刊：
影响因子：
9.4
通讯作者：
Maass, R.
中科院分区：
文献类型：
--
作者：
Liu, C.;Roddatis, V.;Maass, R.
应变局部化到金属玻璃中的剪切带中通常被描述为发生在纳米级的机制，留下厚度为10-20 nm的剪切缺陷。在这里，我们样本的结构，一个单一的系统跨越剪切带，进行了所有的塑性流动与高角度环形暗场扫描透射电子显微镜（HAADF-STEM）和高能X射线断层扫描（XRT）。研究发现，剪切带厚度和密度相对于基体的变化敏感地依赖于沿剪切带沿着的位置。剪切带厚度（10 nm-210 nm）和密度变化（-1%至-12%）的宽分布被揭示。剪切带厚度和密度变化之间没有明显的相关性，但较大的厚度通常对应于较高的密度变化。在剪切带平面上识别出超过100个微米尺寸的剪切带空腔，并且它们的三维排列表明剪切平面的强烈波动的局部曲率。这些发现敦促一个更复杂的剪切带比一个简单的纳米级平面缺陷的看法。(C)2017 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
Strain localization into shear bands in metallic glasses is typically described as a mechanism that occurs at the nano-scale, leaving behind a shear defect with a thickness of 10-20 nm. Here we sample the structure of a single system-spanning shear band that has carried all plastic flow with high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and high-energy x-ray tomography (XRT). It is found that the shear-band thickness and the density change relative to the matrix sensitively depend on position along the shear band. A wide distribution of shear-band thickness (10 nm-210 nm) and density change (-1% to -12%) is revealed. There is no obvious correlation between shear-band thickness and density change, but larger thicknesses correspond typically to higher density changes. More than 100 micron-size shear-band cavities were identified on the shear-band plane, and their three- dimensional arrangement suggests a strongly fluctuating local curvature of the shear plane. These findings urge for a more complex view of a shear band than a simple nano-scale planar defect. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.