New Insights into Deformation of Metallic Glasses by Combining Mesoscale Simulation and Fluctuation Electron Microscopy
New Insights into Deformation of Metallic Glasses by Combining Mesoscale Simulation and Fluctuation Electron Microscopy
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DOI：
10.1017/s1431927616008023
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发表时间：
2016-07
影响因子：
2.8
通讯作者：
P. Zhao;Soohyun Im;Jinwoo Hwang;Yunzhi Wang
中科院分区：
文献类型：
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作者：
P. Zhao;Soohyun Im;Jinwoo Hwang;Yunzhi Wang
我们提出了一种新的金属玻璃（mg）的中尺度变形模型，该模型结合了来自波动电子显微镜（FEM）的纳米尺度原子有序信息。了解镁合金的变形机制，包括室温下的剪切带，对于克服其有限的延性和早期破坏至关重要，这是镁合金广泛应用的主要障碍。目前的理解将剪切带的产生归因于剪切转变区（STZs）之间的集体相互作用，其中剪切变形发生在纳米尺度体积[1]的一组原子之间。我们之前的研究表明，涉及不同STZ类型的中尺度模拟可以提供有用的见解，了解剪切带和mggs的整体变形特征，超出了原子模拟的时间和长度尺度[2]。在这里，我们证明了通过将实验测量的中范围有序（MRO）信息直接结合到我们模型中的异质随机STZ环境中，可以实现更真实的变形模拟。我们的方法是基于这样的假设，即每一种MRO类型，位于STZ的相同长度尺度上，将有一组不同的参数来表征STZ事件，这也被其他人指出了[见例3]。
We present a new mesoscale deformation model of metallic glasses (MGs) that incorporates nanoscale atomic ordering information from fluctuation electron microscopy (FEM). Understanding the deformation mechanism of MGs, including shear banding at room temperature, is crucial to overcome their limited ductility and early failure, which have been a major obstacle to widespread applications of MGs. The current understanding attributes shear band initiation to collective interaction among shear transformation zones (STZs) where shear deformation occurs among a group of atoms in a nanoscale volume [1]. We previously showed that mesoscale simulation involving diverse STZ types can provide useful insights into shear banding and overall deformation characteristics of MGs beyond the time and length scale of atomistic simulations [2]. Here we demonstrate that more realistic deformation simulations can be achieved by incorporating the experimentally measured medium range ordering (MRO) information using FEM directly into the heterogeneously randomized STZ environment in our model. Our approach is based on the assumption that each MRO type, which resides at the same length scale of STZ, will have a different set of parameters that characterize the STZ events, which has also been indicated by others [see, e.g., 3].