Lu Xiaoqian, Feng Shidong, Li Lin, Wang Li-Min, Liu Riping
State Key Laboratory of Metastable Materials Science and Technology, and College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, China.
School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States.
J Phys Chem Lett. 2023 Aug 10;14(31):6998-7006. doi: 10.1021/acs.jpclett.3c01674. Epub 2023 Jul 31.
Due to the chaotic structure of amorphous materials, it is challenging to identify defects in metallic glasses. Here we tackle this problem from a thermodynamic point of view using atomic vibrational entropy, which represents the inhomogeneity of atomic contributions to vibrational modes. We find that the atomic vibrational entropy is correlated to the vibrational mean-square displacement and polyhedral volume of atoms, revealing the critical role of vibrational entropy in bridging dynamics, thermodynamics, and structure. On this method, the local vibrational entropy obtained by coarse-graining the atomic vibrational entropy in space can distinguish more effectively between liquid-like and solid-like atoms in metallic glasses and establish the correlation between the local vibrational entropy and the structure of metallic glasses, offering a route to predict the plastic events from local vibrational entropy. The local vibration entropy is a good indicator of thermally activated and stress-driven plastic events, and its predictive ability is better than that of the structural indicators.
由于非晶态材料的结构混乱，识别金属玻璃中的缺陷具有挑战性。在这里，我们从热力学角度利用原子振动熵来解决这个问题，原子振动熵代表了原子对振动模式贡献的不均匀性。我们发现原子振动熵与原子的振动均方位移和多面体体积相关，揭示了振动熵在连接动力学、热力学和结构方面的关键作用。基于这种方法，通过在空间中对原子振动熵进行粗粒化得到的局部振动熵能够更有效地区分金属玻璃中类液态和类固态原子，并建立局部振动熵与金属玻璃结构之间的相关性，为从局部振动熵预测塑性事件提供了一条途径。局部振动熵是热激活和应力驱动塑性事件的良好指标，其预测能力优于结构指标。
