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arXiv 2201.07857cond-mat.dis-nn
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金属玻璃快速弛豫的瞬态性质

Transient Nature of Fast Relaxation in Metallic Glass

Leo Zella, Jaeyun Moon, David Keffer, Takeshi Egami

摘要:

金属玻璃在远低于玻璃化转变的温度下表现出快速的机械弛豫,其中之一显示出几乎不随温度变化,称为近恒定损耗(NCL)。尽管这一现象对老化和变形有重要意义,但松弛的起源尚不清楚。通过分子动力学模拟的模型金属玻璃,Cu_(64. 5)Zr_(35. 5),我们实现了动态力学分析与系统应力分解成原子级应力,以确定组的原子负责NCL。这项工作表明,NCL弛豫是由于完全瞬态组的原子,成为正常的皮秒时间尺度。它们在空间上分布在整个玻璃中,没有突出的特征,而不是像以前报道的那样有缺陷。

英文摘要:

Metallic glasses exhibit fast mechanical relaxations at temperatures well below the glass transition, one of which shows little variation with temperature known as nearly constant loss (NCL). Despite the important implications of this phenomenon to in aging and deformation, the origin of the relaxation is unclear. Through molecular dynamics simulations of a model metallic glass, Cu_64.5Zr_35.5, we implement dynamic mechanical analysis with system stress decomposed into atomic-level stresses to identify the group of atoms responsible for NCL. This work demonstrates that NCL relaxation is due to fully transient groups of atoms that become normal over picosecond timescales. They are spatially distributed throughout the glass and have no outstanding features, rather than defect-like as previously reported.

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