Controlling interface structure in nanoglasses produced through hydrostatic compression of amorphous nanoparticles
Controlling interface structure in nanoglasses produced through hydrostatic compression of amorphous nanoparticles
复制标题
DOI：
10.1103/physrevmaterials.3.035602
复制
发表时间：
2019-03-20
影响因子：
3.4
通讯作者：
Trelewicz, Jason R.
中科院分区：
文献类型：
--
作者：
Cheng, Bin;Trelewicz, Jason R.
控制金属纳米玻璃中的玻璃-玻璃界面对于调整其机械性能至关重要，特别是通过分布式剪切带形成抑制严重应变局部化的能力。在本文中，采用分子动力学来量化通过无定形纳米颗粒的静水压缩产生的可扩展纳米玻璃模型中的界面结构特征。使用基于膨胀和原子体积分布之间的相关性区分界面与非晶晶粒的框架，我们发现纳米玻璃模型中的界面表现出体积分数为 0.36、宽度约为 2 nm、过剩自由体积为 1-2%，完整二十面体 (FI) 分数约为块体金属玻璃对应物的 30%。虽然这些特性相对于其他纳米玻璃模型（例如平面界面和泊松-沃罗诺伊结构）在数量上是独特的，但它们与由惰性气体冷凝产生的玻璃纳米粒子固结而成的纳米玻璃的实验结果一致。提高固结温度可提高 FI 分数，并对界面产生强烈的偏向，从而展示了调节纳米玻璃界面性能的途径。
Controlling glass-glass interfaces in metallic nanoglasses is essential for tuning their mechanical properties and in particular, the ability to inhibit severe strain localization through distributed shear band formation. In this paper, molecular dynamics are employed to quantify the structural characteristics of interfaces in a scalable nanoglass model produced through hydrostatic compression of amorphous nanoparticles. Using a framework for distinguishing interfaces from amorphous grains based on the correlation between dilatation and atomic volume distributions, we show that the interfaces in our nanoglass model exhibit a volume fraction of 0.36, a width of approximately 2 nm, excess free volume of 1-2%, and full icosahedral (FI) fraction roughly 30% that of a bulk metallic glass counterpart. While these characteristics are quantitatively unique relative to other nanoglass models (e.g., planar interfaces and Poisson-Voronoi constructions), they are consistent with experimental results reported for nanoglasses consolidated from glassy nanoparticles produced through inert gas condensation. Increasing the consolidation temperature enhanced the FI fraction with a strong bias to the interfaces, thus demonstrating a route for tuning interfacial properties in nanoglasses.