Atomic vibration as an indicator of the propensity for configurational rearrangements in metallic glasses,Materials Horizons

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Atomic vibration as an indicator of the propensity for configurational rearrangements in metallic glasses
Materials Horizons ( IF 12.2 ) Pub Date : 2021-07-12 , DOI: 10.1039/d1mh00491c
Huiyang Fan _{1,

2} , Zhao Fan ₂ , Xiongjun Liu ₁ , Zhaoping Lu ₁ , En Ma ₃

Affiliation

In a metallic glass (MG), the propensity for atomic rearrangements varies spatially from location to location in the amorphous solid, making the prediction of their likelihood a major challenge. One can attack this problem from the “structure controls properties” standpoint. But all the current structure-centric parameters are mostly based on local atomic packing information limited to short-range order, hence falling short in reliably forecasting how the local region would respond to external stimuli (e.g., temperature and/or stress). Alternatively, one can use indicators informed by physical properties to bridge the static structure on the one hand, and the response of the local configuration on the other. A sub-group of such physics-informed quantities consists of atomic vibration parameters, which will be singled out as the focus of this article. Here we use the Cu₆₄Zr₃₆ alloy to systematically demonstrate the following two points, all using a single model MG. First, we show in a comprehensive manner the interrelation among common vibrational parameters characterizing the atomic vibrational amplitude and frequency, including the atomic mean square displacement, flexibility volume, participation fraction in the low-frequency vibrational modes and boson peak intensity. Second, we demonstrate that these vibrational parameters fare much better than purely static structural parameters based on local geometrical packing in providing correlation with the propensity for local configurational transitions. These vibrational parameters also share a correlation length similar to that in structural rearrangements induced by external stimuli. This success, however, also poses a challenge, as it remains to be elucidated as to why short-time dynamical (vibrational) behavior at the bottom of the energy basin can be exploited to project the height of the energy barrier for cross-basin activities and in turn the propensity for locally collective atomic rearrangements.

中文翻译：

原子振动作为金属玻璃中构型重排倾向的指标

在金属玻璃 (MG) 中，原子重排的倾向在无定形固体中的不同位置在空间上不同，这使得预测它们的可能性成为一项重大挑战。可以从“结构控制属性”的角度来解决这个问题。但是当前所有以结构为中心的参数大多基于仅限于短程顺序的局部原子堆积信息，因此无法可靠地预测局部区域对外部刺激（例如、温度和/或应力）。或者，可以使用由物理特性通知的指标一方面桥接静态结构，另一方面桥接本地配置的响应。此类物理量的一个子组由原子振动参数组成，这些参数将作为本文的重点。这里我们使用 Cu ₆₄ Zr ₃₆合金系统地论证了以下两点，均使用单一模型MG。首先，我们全面展示了表征原子振幅和频率的常见振动参数之间的相互关系，包括原子均方位移、柔度、低频振动模式中的参与率和玻色子峰强度。其次，我们证明了这些振动参数比基于局部几何堆积的纯静态结构参数在提供与局部构型转变倾向的相关性方面要好得多。这些振动参数也具有与外部刺激引起的结构重排相似的相关长度。然而，这种成功也带来了挑战，

更新日期：2021-08-02

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