3D microscopy at the nanoscale reveals unexpected lattice rotations in deformed nickel

• 成果类型: Article
• 署名作者: He, Qiongyao; Schmidt, Soren; Zhu, Wanquan; Wu, Guilin; Huang, Tianlin; Zhang, Ling; Jensen, Dorte Juul; Feng, Zongqiang; Godfrey, Andrew; Huang, Xiaoxu
• 署名单位: Chongqing University; European Spallation Source (ESS); Chongqing University; Chongqing University; University of Science & Technology Beijing; Technical University of Denmark; Tsinghua University
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-8799
• DOI: 10.1126/science.adj2522
• 发表日期: 2023-12-01
• 页码: 1065-1069
• 关键词: grain rotation; plastic-deformation; nanocrystalline; metals; mechanism; BOUNDARIES; STABILITY; strain

摘要

In polycrystalline metals, plastic deformation is accompanied by lattice rotations resulting from dislocation glide. Following these rotations in three dimensions requires nondestructive methods that so far have been limited to grain sizes at the micrometer scale. We tracked the rotations of individual grains in nanograined nickel by using three-dimensional orientation mapping in a transmission electron microscope before and after in situ nanomechanical testing. Many of the larger-size grains underwent unexpected lattice rotations, which we attributed to a reversal of rotation during unloading. This inherent reversible rotation originated from a back stress-driven dislocation slip process that was more active for larger grains. These results provide insights into the fundamental deformation mechanisms of nanograined metals and will help to guide strategies for material design and engineering applications.