Microscopic Structural Evolution during Ultrastable Metallic Glass Formation

作者：P. Luo, Fan Zhu, Yu-Miao Lv, Zhen Lu, Laiquan Shen, Rui Zhao, Yitao Sun, G. Vaughan, Marco Di Michiel, Beatrice Ruta, H. Y. Bai, Weihua Wang · 发表于：ACS Applied Materials & Interfaces · 年份：2021 · DOI：10.1021/acsami.1c10716 · 被引用次数：23 · 研究领域：Metallic Glasses and Amorphous Alloys、Material Dynamics and Properties、Theoretical and Computational Physics

By decreasing the rate of physical vapor deposition, ZrCuAl metallic glasses with improved stability and mechanical performances can be formed, while the microscopic structural mechanisms remain unclear. Here, with scanning transmission electron microscopy and high-energy synchrotron X-ray diffraction, we found that the metallic glass deposited at a higher rate exhibits a heterogeneous structure with compositional fluctuations at a distance of a few nanometers, which gradually disappear on decreasing the deposition rate; eventually, a homogeneous structure is developed approaching ultrastability. This microscopic structural evolution suggests the existence of the following two dynamical processes during ultrastable metallic glass formation: a faster diffusion process driven by the kinetic energy of the depositing atoms, which results in nanoscale compositional fluctuations, and a slower collective relaxation process that eliminates the compositional and structural heterogeneity, equilibrates the deposited atoms, and strengthens the local atomic connectivity.