基于透射电镜暗场圆锥扫描模式的纳米结构材料微观组织可视化方法
蔡 炜1，朱万全1，2，4*，黄潇冰1，尉 瑞1，黄天林1，2，3，4，吴桂林1，黄晓旭1，2*
（1.重庆大学材料科学与工程学院，轻合金材料国际合作联合实验室（MOE），重庆 400044；2.重庆大学高端装备机械传动全国重点实验室，重庆 400044；3.重庆大学前沿交叉学科研究院，重庆 400044；4.重庆大学超瞬态装置实验室，重庆 401331）
摘 要 纳米结构材料的微观组织表征是理解其结构-性能关系的重要桥梁。基于衍射衬度的透射电镜明、暗场像仅能获得部分晶粒的形态和尺寸，难以高效表征纳米结构材料的微观组织。本文提出了一种基于暗场圆锥扫描模式的微观组织可视化方法，将配准的系列圆锥扫描暗场像中同一个像素位置的强度值组成一阶张量，计算每个像素位置与其相邻8个像素位置对应的一阶张量距离指标（Distance metric）的平均值进而重构微观组织。使用该方法表征了纳米晶铜和层状纳米结构铝合金的微观组织。结果表明，本文的方法能够可视化表征区域内完整的晶界网络，晶界网络中晶粒的形态和尺寸与明场像和暗场像中的基本一致。
关键词 透射电镜显微术；暗场圆锥扫描；纳米结构材料；微观组织；晶粒尺寸
中图分类号：O766+.1；TG113.1；TG146；TG115.21+5.3 文章标识码：A Doi:10.3969/j.issn.1000-6281.2025.05.009
A visualization method for the microstructure of nanostructured materials based on dark-field conical scanning technique in TEM
CAI Wei1, ZHU Wanquan1，2，4*, HUANG Xiaobing1, WEI Rui1, HUANG Tianlin1，2，3，4,
WU Guilin1, HUANG Xiaoxu1，2*
(1. International Joint Laboratory for Light Alloys (MOE), College of Materials Science and Engineering, Chongqing University, Chongqing 400044; 2. State Key Laboratory of Mechanical Transmission for Advanced Equipment, Chongqing University, Chongqing, 400044; 3. Institute of Advanced Interdisciplinary Studies,Chongqing University, Chongqing, 400044; 4. Laboratory for Ultrafast Transient Facility, Chongqing University, Chongqing 401331, China)
Abstract Characterizing the microstructure of nanostructured materials is essential for understanding their structure–property relationships. Conventional bright-field and dark-field imaging in transmission electron microscopy (TEM), which relies on diffraction contrast, typically reveals only partial information on grain morphology and size, limiting its efficiency for comprehensive microstructural analysis. In this study, we propose a visualization method based on conical-scanning dark-field TEM for efficient microstructural reconstruction. A series of registered CSDF images is acquired, and for each pixel location, the corresponding intensity values across the image stack are assembled into a first-order tensor. A distance metric is then calculated between each pixel’s tensor and those of its eight neighboring pixels, with the average distance used to reconstruct the microstructural features. This method is applied to nanocrystalline copper and a lamellar-nanostructured aluminum alloy. The results demonstrate that the proposed approach enables visualization of complete grain boundary networks within the field of view, with grain morphologies and sizes consistent with those observed in conventional bright-field and dark-field images.
Keywords transmission electron microscopy; dark-field conical scanning; nanostructured materials; microstructure; grain size
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