Understanding the atomic structure of shear bands in metallic glass using a newly developed STEM diffraction technique: RDF imaging

在这项计划中，我们计划首次提供大块金属玻璃(BMG)剪切带原子结构的直接实验验证，并利用径向分布函数成像(RDFI)将它们与母体进行比较。结构研究将集中在键长、键角和配位数方面的中短程原子有序性以及它们在各个剪切带中的变化。原子密度、拓扑和化学有序的相应变化将与理论模拟和其他间接实验观测进行比较。这些结果将是理解剪切带形成过程中的关键信息，并为将BMG的结构和机械性能联系起来创造一个起点。能够对非晶相进行详细的局部结构分析的基本方法将进一步改进和扩展，以表征非均质玻璃材料中的单个剪切带和变化。

Within the proposed project, we plan to provide the first direct experimental verification of the atomic-structure in shear bands of bulk metallic glasses (BMGs) and compare them with the parent matrix by using radial distribution function imaging (RDFI). The structural investigation will focus on the short- and medium range atomic order in terms of bond length, bond angle and coordination number and their variation in individual shear bands. The corresponding changes in atomic density, topological and chemical order will be compared to theoretical simulations and other indirect experimental observations. The results will be key information to understand the processes during shear band formation and create a starting point to correlate the structure and mechanical properties of BMGs. The principle method enabling a detailed local structural analysis of amorphous phase will be further improved and extended to characterize individual shear bands and variations in heterogeneous glassy materials.