发表机构
The Ohio State University; University of Michigan; Federal Institute of Materials Research and Testing; Seoul National University; Denison University; Korea Basic Science Institute（俄亥俄州立大学; 密歇根大学; 联邦材料研究与测试研究所; 首尔国立大学; 丹尼森大学; 韩国基础科学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究结合同步辐射G(r)与4D-STEM，发现几何和拓扑中程有序共同决定Zr基金属玻璃的延展性，其中Zr含量增加通过抑制FCC类有序并促进HCP类有序来提升延展性。
AI 中文摘要
金属玻璃表现出显著的成分依赖性力学性能，然而识别这些变化的微观结构起源仍然困难。一个悬而未决的问题是如何关联不同形式的中程有序（MRO），这些中程有序在不同长度尺度上定义，并通过不同的实验观测手段获取，以及理解它们与性能的联系。我们将同步辐射约化密度函数G(r)与机器学习辅助的四维扫描透射电子显微镜（4D-STEM）相结合，研究了五种Zr基金属玻璃中的几何和拓扑中程有序。G(r)的密度波分析通过原子密度相关的相干长度提供了几何中程有序的描述符，而4D-STEM揭示了纳米尺度的拓扑和化学中程有序图案，包括具有不同旋转对称性的类晶体局域有序。我们表明，由G(r)导出的相干长度捕捉了协同延性弛豫的重要基线趋势，而成分依赖的拓扑中程有序提供了额外的结构贡献，有助于解释观察到的力学响应。特别是，增加Zr含量抑制了富Cu的面心立方（FCC）类中程有序，增加了协同相干体积，并促进了与增强延展性相关的富Zr的六方密排（HCP）类局域有序。这些结果确定了几何和拓扑中程有序的综合结构影响是金属玻璃成分依赖性力学响应的关键基础。
英文摘要
Metallic glasses exhibit pronounced composition-dependent mechanical properties, yet identifying the structural origins of these changes remains difficult. An outstanding issue is how to correlate different forms of medium range order (MRO), defined at different length scales and accessed through different experimental observables, and to understand their connection to properties. We combine synchrotron reduced density function, G(r), with machine-learning-assisted four dimensional scanning transmission electron microscopy (4D-STEM) to examine geometric and topological MRO in five Zr-based metallic glasses. Density wave analysis of G(r) provides a geometric MRO descriptor through the coherence length of atomic density correlations, while 4D-STEM reveals nanoscale topological and chemical MRO motifs, including crystal-like local ordering with distinct rotational symmetries. We show that the G(r)-derived coherence length captures an important baseline tendency for cooperative ductile relaxation, while composition-dependent topological MRO provides an additional structural contribution that helps explain the observed mechanical responses. In particular, increasing Zr content suppresses Cu-rich FCC-like MRO, increases the cooperative coherence volume, and promotes fine Zr-rich HCP-like local order associated with enhanced ductility. These results identify the combined structural influence of geometric and topological MRO as a key basis for composition-dependent mechanical response in metallic glasses.
