Zheng Kaifeng, Yuan Suyue, Hahn Horst, Branicio Paulo S
Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 3651 Watt Way, Los Angeles, CA, 90089, USA.
Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Germany.
Sci Rep. 2021 Sep 28;11(1):19246. doi: 10.1038/s41598-021-98494-8.
Nanoglass (NG) as a new structure-tunable material has been investigated using both experiments and computational modeling. Experimentally, inert gas condensation (IGC) is commonly employed to prepare metallic glass (MG) nanoparticles that are consolidated using cold compression to generate an NG. In computational modeling, various methods have been used to generate NGs. However, due to the high computational cost involved, heretofore modeling investigations have not followed the experimental synthesis route. In this work, we use molecular dynamics simulations to generate an NG model by consolidating IGC-prepared CuZr nanoparticles following a workflow similar to that of experiments. The resulting structure is compared with those of NGs produced following two alternative procedures previously used: direct generation employing Voronoi tessellation and consolidation of spherical nanoparticles carved from an MG sample. We focus on the characterization of the excess free volume and the Voronoi polyhedral statistics in order to identify and quantify contrasting features of the glass-glass interfaces in the three NG samples prepared using distinct methods. Results indicate that glass-glass interfaces in IGC-based NGs are thicker and display higher structural contrast with their parent MG structure. Nanoparticle-based methods display excess free volume exceeding 4%, in agreement with experiments. IGC-prepared nanoparticles, which display Cu segregation to their surfaces, generate the highest glass-glass interface excess free volume levels and the largest relative interface volume with excess free volume higher than 3%. Voronoi polyhedral analysis indicates a sharp drop in the full icosahedral motif fraction in the glass-glass interfaces in nanoparticle-based NG as compared to their parent MG.
纳米玻璃（NG）作为一种新型的结构可调材料，已通过实验和计算建模进行了研究。在实验方面，通常采用惰性气体凝聚法（IGC）制备金属玻璃（MG）纳米颗粒，然后通过冷压将其固结以生成NG。在计算建模中，已使用各种方法来生成NG。然而，由于涉及高昂的计算成本，迄今为止，建模研究并未遵循实验合成路线。在这项工作中，我们使用分子动力学模拟，按照与实验类似的工作流程，通过固结IGC制备的CuZr纳米颗粒来生成NG模型。将所得结构与先前使用的另外两种方法制备的NG结构进行比较：采用Voronoi镶嵌直接生成以及固结从MG样品中切割出的球形纳米颗粒。我们专注于对过量自由体积和Voronoi多面体统计进行表征，以便识别和量化使用不同方法制备的三种NG样品中玻璃-玻璃界面的对比特征。结果表明，基于IGC的NG中的玻璃-玻璃界面更厚，并且与其母体MG结构相比显示出更高的结构对比度。基于纳米颗粒的方法显示出超过4%的过量自由体积，这与实验结果一致。表面出现Cu偏析的IGC制备的纳米颗粒产生了最高的玻璃-玻璃界面过量自由体积水平以及最大的相对界面体积，过量自由体积高于3%。Voronoi多面体分析表明，与母体MG相比，基于纳米颗粒的NG中玻璃-玻璃界面的全二十面体 motif 分数急剧下降。
