电子背散衍射花样的数学特征

电子背散衍射(EBSD)花样揭示了材料的物相成分、晶体结构、晶粒取向、晶粒大小和晶界的信息。EBSD花样非常复杂,通常需要借助专门的计算软件才能解析。本文系统地研究了EBSD花样的数学特征,建立了任意晶体取向与EBSD花样之间的数理关系,推导了面心立方、体心立方和六方晶体的基本晶带轴的理论EBSD花样的数学特征,以及面心立方晶体的(001)<110>取向和(001)<100>取向的理论菊池(Kikuchi)花样特征。在实测EBSD花样的分析中与各晶系各点阵的基本晶带轴的理论EBSD花样特征比较,即通过图像特征对比,就可以直接确定实测EBSD花样所属的晶系、点阵和Kikuchi线交点对应的晶带轴uvw],再由基本晶带轴的坐标计算出晶体取向,还能提供基本晶面信息,如原子密排晶面在样品中的空间分布,这有利于晶体的变形或生长机理研究。EBSD为单晶芯片质量检验提供了新方法。

Mathematical Characterization of Electron Backscattering Diffraction Patterns

Electron backscattering diffraction (EBSD) patterns reveal information about the phase component, crystal structure, grain orientation, grain size and grain boundaries of the material. EBSD patterns are very complex and usually require special computing software to analyze. A systematic study of the mathematical characteristics of EBSD patterns is carried out in this paper. A mathematical relationship between arbitrary crystal orientation and EBSD pattern is established, mathematical characteristics of EBSD patterns at pattern center of the basal zone axes of face-centered cubic, body-centered cubic, and close-packed hexagonal crystals are derived, as well as the theoretical Kikuchi patterns of (001)<110> orientation and (001)<100> orientation of face-centered cubic crystals. The theoretical EBSD pattern characteristics of the basic crystal zone axes of each lattice are compared in the analysis of the measured EBSD patterns, that is, by comparing the image features, the crystal system, lattice and the crystal zone axes uvw] corresponding to the intersection points of some Kikuchi lines of the measured patterns can be directly determined. The crystal orientation or texture can be calculated from the coordinates of the basic crystal zone axes, and the spatial distribution of the basic crystal plane can also be provided, such as atomic close-packed plane in the sample, which is beneficial to the study on the deformation or growth mechanism of the crystal. EBSD provides new methods for single-crystal chip quality inspection.