本文件描述了使用电子背散射衍射（EBSD）测量二维抛光横截面的平均晶粒尺寸的程序。这需要测量取向、错取向和图案质量因子，作为晶体样品中位置的函数。本文件中的测量是在二维截面上进行的。读者应仔细注意所使用的定义（3.3），这些定义区分了测量的截面晶粒度和可从中导出的与三维晶粒度相关的平均晶粒度。 注1:虽然使用光学显微镜测定晶粒尺寸的传统方法已经成熟，但与这些技术相比，EBSD方法具有许多优势，包括提高了空间分辨率和晶粒取向的定量描述。 注2:该方法也适用于测量复杂材料的粒度，例如具有显著双重成分的材料。 注3:警告读者，在试图调查高变形程度的试样时，应谨慎解释结果。

This document describes procedures for measuring average grain size derived from a two-dimensional polished cross-section using electron backscatter diffraction (EBSD). This requires the measurement of orientation, misorientation and pattern quality factor as a function of position in the crystalline specimen^[1]. The measurements in this document are made on two dimensional sections. The reader should note carefully the definitions used (3.3) which draw a distinction between the measured sectional grain sizes, and the mean grain size which can be derived from them that relates to the three dimensional grain size. NOTE 1 While conventional methods for grain size determination using optical microscopy are well-established, EBSD methods offer a number of advantages over these techniques, including increased spatial resolution and quantitative description of the orientation of the grains. NOTE 2 The method also lends itself to the measurement of the grain size of complex materials, for example those with a significant duplex content. NOTE 3 The reader is warned to interpret the results with care when attempting to investigate specimens with high levels of deformation.