Quantitative Measurement of Density in a Shear Band of Metallic Glass Monitored Along its Propagation Direction.
Quantitative Measurement of Density in a Shear Band of Metallic Glass Monitored Along its Propagation Direction.
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DOI：
10.1103/physrevlett.115.035501
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发表时间：
2015-05
影响因子：
8.6
通讯作者：
V. Schmidt;H. Rösner;M. Peterlechner;G. Wilde;P. Voyles
中科院分区：
文献类型：
--
作者：
V. Schmidt;H. Rösner;M. Peterlechner;G. Wilde;P. Voyles
电子散射定量密度测量结果表明，Al_（88）Y_（77）Fe_（5）金属玻璃中的剪切带相对于未变形基体呈现出高密度区和低密度区交替出现的现象，其范围为-9%~+6%。剪切带从主传播方向的小偏转与密度从高于矩阵到低于矩阵的开关相一致，反之亦然，表明在传播过程中发生更快和更慢的运动（粘滑）。纳米束衍射分析提供了明确的证据，密度变化伴随着结构的变化，这表明剪切改变紧密结合的短程或中程原子簇的包装。这与颗粒介质变形后形成的颗粒剪切带中的堆积行为有着惊人的相似之处。
Quantitative density measurements from electron scattering show that shear bands in deformed Al88Y7Fe5 metallic glass exhibit alternating high and low density regions, ranging from -9% to +6% relative to the undeformed matrix. Small deflections of the shear band from the main propagation direction coincide with switches in density from higher to lower than the matrix and vice versa, indicating that faster and slower motion (stick slip) occurs during the propagation. Nanobeam diffraction analyses provide clear evidence that the density changes are accompanied by structural changes, suggesting that shear alters the packing of tightly bound short- or medium-range atomic clusters. This bears a striking resemblance to the packing behavior in granular shear bands formed upon deformation of granular media.