The field of metallurgy has greatly benefited from the development of electron microscopy over the last two decades. Scanning electron microscopy (SEM) has become a powerful tool for the investigation of nano- and microstructures. This article reviews the complete set of tools for crystallographic analysis in the SEM, i.e., electron backscatter diffraction (EBSD), transmission Kikuchi diffraction (TKD), and electron channeling contrast imaging (ECCI). We describe recent relevant developments in electron microscopy, and discuss the state-of-the-art of the techniques and their use for analyses in metallurgy. EBSD orientation measurements provide better angular resolution than spot diffraction in TEM but slightly lower than Kikuchi diffraction in TEM, however, its statistical significance is superior to TEM techniques. Although spatial resolution is slightly lower than in TEM/STEM techniques, EBSD is often a preferred tool for quantitative phase characterization in bulk metals. Moreover, EBSD enables the measurement of lattice strain/rotation at the sub-micron scale, and dislocation density. TKD enables the transmitted electron diffraction analysis of thin-foil specimens. The small interaction volume between the sample and the electron beam enhances considerably the spatial resolution as compared to EBSD, allowing the characterization of ultra-fine-grained metals in the SEM. ECCI is a useful technique to image near-surface lattice defects without the necessity to expose two free surfaces as in TEM. Its relevant contributions to metallography include deformation characterization of metals, including defect visualization, and dislocation density measurements. EBSD and ECCI are mature techniques, still undergoing a continuous expansion in research and industry. Upcoming technical developments in electron sources and optics, as well as detector instrumentation and software, will likely push the border of performance in terms of spatial resolution and acquisition speed. The potential of TKD, combined with EDS, to provide crystallographic, chemical, and morphologic characterizations of nano-structured metals will surely be a valuable asset in metallurgy.

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冶金学中扫描电子显微镜晶体学分析方法的最新进展

在过去的二十年中，冶金学领域极大地受益于电子显微镜的发展。扫描电子显微镜（SEM）已成为研究纳米和微观结构的强大工具。本文介绍了用于SEM中晶体学分析的完整工具集，即电子背散射衍射（EBSD），透射菊池衍射（TKD）和电子通道对比成像（ECCI）。我们描述了电子显微镜的最新发展，并讨论了该技术的最新发展及其在冶金分析中的应用。EBSD取向测量比TEM中的点衍射提供更好的角分辨率，但比TEM中的菊池衍射更低，但是，其统计意义优于TEM技术。尽管空间分辨率略低于TEM / STEM技术，但是EBSD通常是用于定量分析大块金属的首选工具。此外，EBSD能够测量亚微米级的晶格应变/旋转和位错密度。TKD使得能够对薄箔样品进行透射电子衍射分析。与EBSD相比，样品与电子束之间较小的相互作用体积可显着提高空间分辨率，从而可在SEM中表征超细晶粒金属。ECCI是一种使近表面晶格缺陷成像的有用技术，而无需像TEM中那样暴露两个自由表面。它对金相学的相关贡献包括金属的变形表征（包括缺陷可视化）和位错密度测量。EBSD和ECCI是成熟的技术，在研究和行业中仍在不断扩展。电子源和光学技术以及检测器仪器和软件方面即将出现的技术发展，可能会在空间分辨率和采集速度方面推动性能的发展。TKD与EDS结合提供纳米结构金属的晶体学，化学和形态学表征的潜力必将是冶金学中的宝贵资产。