原位透射电镜在纳米多孔金原子尺度变形研究中的应用

Recent progress in the study of atomic⁃scale deformation in nanoporous gold via in situ transmission electron microscopy

纳米多孔金(NPG)具有高曲率、高比表面积的结构特征,且比强度较高,作为一种结构功能一体化材料受到广泛关注。然而,影响NPG实际应用的最大障碍之一是其在拉伸作用下内部单根韧带失效导致的塑性失稳。过去的研究主要集中在宏观力学实验的研究,无法直接观察单根韧带的塑性变形行为。随着原位透射电子显微镜(transmission electron microscopy,TEM)的发展,已具备从原子尺度研究NPG中单根韧带塑性变形过程的能力,这对理解NPG变形机理进而合理设计制备高塑性纳米多孔结构金属具有重要意义。本文主要以近几年利用球差校正透射电子显微镜(Cs⁃corrected TEM)原位原子尺度研究NPG塑性变形的系列工作为例,简要综述了NPG单根韧带在塑性变形过程中位错运动(攀移和滑移)和表面原子扩散行为的最新进展,并对纳米结构金属材料的未来研究进行了展望。

Nanoporous gold(NPG)exhibits unique structural characteristics such as high curvature,high specific surface area,and high specific strength,which have rendered it as a structurally functional integrated material that has attracted significant attention.Despite these unique characteristics,NPG suffers from a major drawback,namely,plastic instability caused by the failure of a single internal ligament under tension,which significantly limits its practical applications.Previous researches mainly focus on macroscopic mechanical experiments,which can not directly observe the plastic deformation behavior of single ligaments.With the development of in situ transmission electron microscopy(TEM),the study of the plastic deformation process of single ligaments in NPG at the atomic scale is of great significance for the understanding of the deformation mechanism of NPG and for the design and the preparation of highly plastic nanoporous metals reasonably.This article mainly shows recent in⁃situ atomic⁃scale studies on NPG plastic deformation using Cs⁃corrected transmission electron microscopy(TEM).The latest progress in dislocation movement(climbing and sliding)and surface atomic diffusion behavior of single NPG ligaments during plastic deformation is discussed.The prospects for future research on nanostructured metal materials are proposed.