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Mapping Shear Bands in Metallic Glasses: From Atomic Structure to Bulk Dynamics
Physical Review Letters ( IF 8.1 ) Pub Date : 2022-06-16 , DOI: 10.1103/physrevlett.128.245501 Huaping Sheng 1 , Daniel Şopu 1, 2 , Simon Fellner 1 , Jürgen Eckert 1, 3 , Christoph Gammer 1
Physical Review Letters ( IF 8.1 ) Pub Date : 2022-06-16 , DOI: 10.1103/physrevlett.128.245501 Huaping Sheng 1 , Daniel Şopu 1, 2 , Simon Fellner 1 , Jürgen Eckert 1, 3 , Christoph Gammer 1
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A deep understanding of the mechanisms controlling shear banding is of fundamental importance for improving the mechanical properties of metallic glasses. Atomistic simulations highlight the importance of nanoscale stresses and strains for shear banding, but corresponding experimental proofs are scarce due to limited characterization techniques. Here, by using precession nanodiffraction mapping in the transmission electron microscope, the atomic density and strain distribution of an individual shear band is quantitatively mapped at 2 nm resolution. We demonstrate that shear bands exhibit density alternation from the atomic scale to the submicron scale and complex strain fields exist, causing shear band segmentation and deflection. The atomic scale density alternation reveals the autocatalytic generation of shear transformation zones, while the density alternation at submicron scale results from the progressive propagation of shear band front and extends to the surrounding matrix, forming oval highly strained regions with density consistently higher () than the encapsulated shear band segments. Through combination with molecular dynamic simulations, a complete picture for shear band formation and propagation is established.
中文翻译：
绘制金属玻璃中的剪切带：从原子结构到体动力学
深入了解控制剪切带的机制对于提高金属玻璃的机械性能至关重要。原子模拟强调了纳米级应力和应变对剪切带的重要性，但由于表征技术有限，相应的实验证明很少。在这里，通过在透射电子显微镜中使用进动纳米衍射映射，以 2 nm 分辨率定量映射单个剪切带的原子密度和应变分布。我们证明剪切带表现出从原子尺度到亚微米尺度的密度交替，并且存在复杂的应变场，导致剪切带分割和偏转。原子尺度密度交替揭示了剪切转变区的自催化生成，) 比封装的剪切带段。通过与分子动力学模拟相结合，建立了剪切带形成和传播的完整图景。
更新日期：2022-06-16
中文翻译：
绘制金属玻璃中的剪切带：从原子结构到体动力学
深入了解控制剪切带的机制对于提高金属玻璃的机械性能至关重要。原子模拟强调了纳米级应力和应变对剪切带的重要性，但由于表征技术有限，相应的实验证明很少。在这里，通过在透射电子显微镜中使用进动纳米衍射映射，以 2 nm 分辨率定量映射单个剪切带的原子密度和应变分布。我们证明剪切带表现出从原子尺度到亚微米尺度的密度交替，并且存在复杂的应变场，导致剪切带分割和偏转。原子尺度密度交替揭示了剪切转变区的自催化生成，) 比封装的剪切带段。通过与分子动力学模拟相结合，建立了剪切带形成和传播的完整图景。
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