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| Temperature dependence and correlation of initial microstructural defects and breaking |
| Author Name | Affiliation | E-mail | | ZHAO Jian-Wei | Key Laboratory of Yarn Materials Forming and Composite Processing Technology, Jiaxing University, Jiaxing, Zhejiang 314001, China | jwzhao@zjxu.edu.cn | | SHEN Kun-Yan | School of Computing and Artificial Intelligence, Southwest Jiaotong University, Chengdu 611756, China | | | YU Xiao-Hui | Key Laboratory of Yarn Materials Forming and Composite Processing Technology, Jiaxing University, Jiaxing, Zhejiang 314001, China | | | HOU Jin | Laboratory of Intelligent Perception and Smart Operation & Maintenance, School of Information Science and Technology, Southwest Jiaotong University, Chengdu 611756, China
National Engineering Laboratory of Integrated Transportation Big Data Application Technology, Southwest Jiaotong University, Chengdu 611756, China | jhou@swjtu.edu.cn |
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| Abstract: The microstructural defects within the nanowire (NW) have a significant impact on the mechanical properties of the NW. The prediction of the breaking position of the NW has raised concerns owning to it is a crucial point in the application of nanodevices. In this work, based on the statistical analysis, the breaking positions and the positions of the initial microstructural defects generated at the stress yield point are studied separately to analyze their temperature dependence, then further investigate the relationship between the breaking failure and the initial microstructural defects. At the temperature range from 20 to 300 K, including six ensembles, the single-crystal Cu NWs have been performed using molecular dynamics (MD) simulations. The ensemble at each temperature includes 300 independent samples. Based on machine learning, the hexagonal close-packed (hcp) atoms at the stress yield point have been clustered to every initial microstructural defect by the density-based spatial clustering of applications with noise (DBSCAN) algorithm. According to the statistical results, it is found that the initial microstructural defects of NWs simulated in this paper tend to generate at the two ends of the NW while the temperature is less than 50 K. Following the increasing temperature, the MD simulation results have shown a strong temperature dependence of mechanical properties for the single-crystal Cu NWs, including Young's modulus, average yield stress, average potential energy, etc. It is attributed that there are more initial microstructural defects generated as the increase in temperature, and the positions of initial microstructural defects are averaged out from the two ends of the distribution towards the middle part. The breaking positions for all the simulation temperatures are mainly concentrated on the ends of the NW. The statistical results indicate that this temperature range has little effect on breaking position but a great effect on the initial microstructural defects. It shows a consistency between the initial slip distributions and breaking distributions while the temperature is less than 100 K. However, it has been observed that the differences between them are gradually shown with the increase in temperature due to their different temperature dependents. The microstructural deformation behaviors under different temperatures reveal that the breaking failure is affected by the surface effect and blocking effect of the ends. Based on the results, the final breaking position is correlated to the middle and late stages of the plastic deformation rather than the positions of initial microstructural defects first generated. |
| Keywords: nanowires initial microstructural defects breaking failure molecular dynamics statistical analysis mechanical properties |
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| ZHAO Jian-Wei,SHEN Kun-Yan,YU Xiao-Hui,HOU Jin.Temperature dependence and correlation of initial microstructural defects and breaking[J].Chinese Journal of Inorganic Chemistry,2023,39(6):1193-1207. |
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