Crystallite size distribution and dislocation structure determined by diffraction profile analysis: principles and practical application to cubic and hexagonal crystals
Crystallite size distribution and dislocation structure determined by diffraction profile analysis: principles and practical application to cubic and hexagonal crystals
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DOI：
10.1107/s0021889801003715
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发表时间：
2001-06
影响因子：
6.1
通讯作者：
T. Ungár;J. Gubicza;G. Ribárik;A. Borbély
中科院分区：
文献类型：
--
作者：
T. Ungár;J. Gubicza;G. Ribárik;A. Borbély
提出了两种不同的衍射面分析方法。首先，用改进的Williamson-Hall和Warren-Averach方法分析了衍射谱的宽度和前几个傅里叶系数。提出了一种在应变作用下测定微晶尺寸分布的简单实用的方法。在第二种方法中，用尺寸和应变分布的从头算函数的傅里叶系数来拟合测量的物理轮廓的傅里叶系数。在这两个过程中，应变各向异性均由均方应变的位错模型来合理化。这些程序在氮化硅纳米晶粉末和严重塑性变形的大块铜试件上进行了应用和测试。并将X射线微晶粒度分布与透射电子显微镜的粒度分布进行了比较。纳米晶疏松粉末的X射线和透射电子显微镜数据吻合较好。在块状材料中，需要对微观结构有更深入的了解，以便将X射线和透射电子显微镜的结果关联起来。
Two different methods of diffraction profile analysis are presented. In the first, the breadths and the first few Fourier coefficients of diffraction profiles are analysed by modified Williamson–Hall and Warren–Averbach procedures. A simple and pragmatic method is suggested to determine the crystallite size distribution in the presence of strain. In the second, the Fourier coefficients of the measured physical profiles are fitted by Fourier coefficients of well established ab initio functions of size and strain profiles. In both procedures, strain anisotropy is rationalized by the dislocation model of the mean square strain. The procedures are applied and tested on a nanocrystalline powder of silicon nitride and a severely plastically deformed bulk copper specimen. The X-ray crystallite size distributions are compared with size distributions obtained from transmission electron microscopy (TEM) micrographs. There is good agreement between X-ray and TEM data for nanocrystalline loose powders. In bulk materials, a deeper insight into the microstructure is needed to correlate the X-ray and TEM results.