Fast Surface Dynamics on a Metallic Glass Nanowire
Fast Surface Dynamics on a Metallic Glass Nanowire
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DOI：
10.1021/acsnano.1c00500
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发表时间：
2021-06-21
期刊：
影响因子：
17.1
通讯作者：
Voyles, Paul M.
中科院分区：
文献类型：
--
作者：
Chatterjee, Debaditya;Annamareddy, Ajay;Voyles, Paul M.
玻璃表面附近的动力学可能比本体快得多。我们使用亚纳米分辨率的电子相关显微镜研究了铂基金属玻璃的表面动力学。我们的研究表明，表面玻璃化转变温度受到类似于 20 K 的抑制。通过在金属玻璃上涂上一层薄薄的无定形碳来抑制表面动力学的增强。 Ni80P20 的并行分子动力学模拟显示，表面玻璃化转变温度具有类似的温度抑制作用，并且增强的表面动力学被与玻璃表面化学结合的覆盖层所抑制。近地表区域的移动性是通过原子笼和跳跃发生的，缓慢的动力学与高笼打破势垒和弦状协作运动之间存在很强的相关性。表面和体动力学随着各自玻璃化转变温度重新调整的温度函数一起崩溃。
The dynamics near the surface of glasses can be much faster than in the bulk. We studied the surface dynamics of a Pt-based metallic glass using electron correlation microscopy with sub-nanometer resolution. Our studies show an similar to 20 K suppression of the glass transition temperature at the surface. The enhancement in surface dynamics is suppressed by coating the metallic glass with a thin layer of amorphous carbon. Parallel molecular dynamics simulations on Ni80P20 show a similar temperature suppression of the surface glass transition temperature and that the enhanced surface dynamics are arrested by a capping layer that chemically binds to the glass surface. Mobility in the near-surface region occurs via atomic caging and hopping, with a strong correlation between slow dynamics and high cage-breaking barriers and stringlike cooperative motion. Surface and bulk dynamics collapse together as a function of temperature rescaled by their respective glass transition temperatures.