超稳Ni-Nb金属玻璃稳定性增强的结构起源

Structural Origin of Enhanced Stability of Ni-Nb Ultrastable Metallic Glass

摘要:

采用模拟气相沉积过程的分子动力学方法，探究Ni-Nb金属玻璃结构随基底温度的演化规律。结果表明：约850 K为最佳基底温度，此时玻璃体系势能最低，稳定性最高。超稳定玻璃的形成伴随着短程有序结构由扭曲二十面体转变为完美二十面体结构。该现象在Mg-Cu-Y、La-Ni-Al、Zr-Cu-Al及Cu-Zr金属玻璃体系中得到进一步验证。本研究明确了超稳定金属玻璃形成的结构起源，可为理解玻璃转变本质提供新视角。

Abstract:

Molecular dynamics simulations were used to simulate the vapor deposition process for the investigation of the structural evolution of Ni-Nb metallic glasses as a function of substrate temperature. Results show that optimal substrate temperature is approximately 850 K, at which the glass attains the lowest potential energy and thus the highest stability. The formation of ultrastable glass is accompanied by a transition of short-range ordered structure from a distorted icosahedron to a perfect icosahedron. This phenomenon can be further confirmed in Mg-Cu-Y, La-Ni-Al, Zr-Cu-Al, and Cu-Zr metallic glass systems. In this research, the structural origin of ultrastable metallic glass formation is established, providing new insights into the nature of the glass transition.