Ding Zhijie, Li Peng, Qin Zhiwei, Huang Weiben, Zhao Peng, Zhou Dianwu, Meng Xiangchen, Sato Yutaka S, Dong Honggang
School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China.
State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle, Hunan University, Changsha 410082, China.
Nano Lett. 2024 Oct 2;24(39):12171-12178. doi: 10.1021/acs.nanolett.4c03115. Epub 2024 Sep 6.
In the pursuit of rapid atomic migration in lightweight Fe-Al diffusion couples, rationally designing short-circuit diffusion paths has become paramount. Herein, a strain-mediated defect engineering strategy was proposed for reducing the vacancy activation energy and enhancing diffusion behaviors along dislocations (DLs) and grain boundaries (GBs). Combining the modified Arrhenius-type relationship, an interfacial apparent activation energy of 139 kJ mol was acquired utilizing defect engineering, which was decreased by about 49%. This was closely related to high-density vacancies, DLs, and GBs formed in strained Fe and Al materials, which provided more low activation energy paths for atomic migration. First-principles calculations indicated that the lattice diffusion barrier mediated by monovacancy was reduced with strain incorporation, attributed to the weakened atom-vacancy bond as a consequence of less electron transport. The synergistic effect of abnormal electron-charge distribution in the bulk and strong attraction force at the Al/Fe interface radically resulted in rapid atomic migration, collectively regulating the "breaking-forming bond" process.
在追求轻质铁铝扩散偶中的快速原子迁移过程中，合理设计短路扩散路径变得至关重要。在此，提出了一种应变介导的缺陷工程策略，以降低空位激活能并增强沿位错（DLs）和晶界（GBs）的扩散行为。结合修正的阿累尼乌斯型关系，利用缺陷工程获得了139 kJ/mol的界面表观激活能，降低了约49%。这与应变铁和铝材料中形成的高密度空位、位错和晶界密切相关，它们为原子迁移提供了更多低激活能路径。第一性原理计算表明，由于电子传输减少导致原子-空位键减弱，单空位介导的晶格扩散势垒随应变引入而降低。体相中异常电子电荷分布与铝/铁界面处强吸引力的协同效应从根本上导致了快速原子迁移，共同调节“断键-成键”过程。
