透射电镜带轴系列倾转的数学模型设计

Design of mathematical model for tilting series of zone axes in TEM

透射电镜(TEM)是一个集多功能于一体的微结构表征工具,对分析材料的形貌、结构和性能意义较大。TEM采集的数据是三维物体在二维空间的投影图,想要得到全面准确的信息,需将样品倾转至特定晶带轴方向。晶带轴系列倾转的操作主要依赖菊池极的位置,然而由于不同晶带轴之间的角度相差较大,在荧光屏上难以观测到多个不同菊池极,且倾转过程中样品位置会发生大幅度偏移,需在衍射和成像模式之间反复多次切换方可获得理想的结果。为降低带轴系列倾转的操作难度,该文建立数学模型,通过测量菊池线与水平方向的夹角,可简单快速地获得目标晶带轴所需的倾转角度。该工作为高校充分利用TEM检测晶体微观结构、确定取向关系提供具体的理论和实验指导。

Transmission electron microscope(TEM) is a multi-functional microstructure characterization tool,which is of great significance to analyze the morphology, structure and performance for materials. The data collected by TEM is projections of three-dimensional objects in two-dimensional space. In order to obtain comprehensive and accurate information, it is necessary to tilt the sample to the direction of specific crystal zone-axes. The operation of tilting zone-axes in series mainly depends on the position of Kikuchi poles. However,due to the large difference of angles between different crystal zone-axes, it is difficult to observe multiple different Kikuchi poles on the phosphor screen. In addition, the sample position will be shifted greatly during the tilting process, and desired results can only be obtained by repeatedly switching between diffraction and imaging modes.In order to reduce the operating difficulty of tilting zone-axes in series, a mathematical model is established in this paper. By measuring the angle between Kikuchi line and horizontal direction, the tilting angle required by the target belt axis can be obtained simply and quickly. By measuring the angle between the Kikuchi line and the horizontal direction, the tilting angle required of the target crystal zone-axes can be obtained quickly and simply.This work provides specific theoretical and experimental guidance for colleges and universities to make full use of TEM to detect the microstructure of crystals and determine the orientation relationship.