Direct determination of structural heterogeneity in metallic glasses using four-dimensional scanning transmission electron microscopy
Direct determination of structural heterogeneity in metallic glasses using four-dimensional scanning transmission electron microscopy
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DOI：
10.1016/j.ultramic.2018.09.005
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发表时间：
2018-12-01
期刊：
影响因子：
2.2
通讯作者：
Hwang, Jinwoo
中科院分区：
文献类型：
--
作者：
Im, Soohyun;Chen, Zhen;Hwang, Jinwoo
我们首次报道了利用四维(4-D)扫描电子显微镜(STEM)数据的强度变化和角相关分析来直接量化金属玻璃中的结构不均一性。我们证明，用像素化的快速STEM探测器获得的4-D纳米衍射数据的实空间重建和分析能够定量地确定局部结构异质性的细节，包括纳米到介观尺度上的局部有序的类型、尺寸、体积分数和空间分布，这超出了以前使用传统探测器的测量的限制。我们发现，在Zr55Co25Al20玻璃中存在不同类型的局域有序化，导致了高度的结构异质性，局域有序区的总体积占总体积的14%。这些发现意义重大，因为由于缺乏来自实验的详细结构信息，金属玻璃和其他非晶态材料的结构-性质关系一直难以确定。
We report the first direct quantification of the structural heterogeneity in metallic glasses using intensity variance and angular correlation analyses of the 4-dimensional (4-D) scanning transmission electron microscopy (STEM) data. We demonstrate that the real-space reconstruction and analyses of the 4-D nanodiffraction data acquired using a pixelated fast STEM detector enables quantitative determination of the details of local structural heterogeneity, including the type, size, volume fraction and spatial distribution of local ordering at the nano- to meso-scale, beyond the limits of the previous measurements using conventional detectors. We show that different types of local ordering are present in Zr55Co25Al20 glass, leading to a high degree of structural heterogeneity, with the total volume of locally ordered regions making up to 14% of the entire volume. These findings are significant, as the structure-property relationship in metallic glasses and other amorphous materials has been difficult to establish because of the lack of detailed structural information from experiments.