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Generalization of X-ray microanalysis in analytical electron microscopy and its application to microstructure-controlled materials

分析电子显微镜中X射线微分析的推广及其在微结构控制材料中的应用

基本信息

批准号：
03650580
负责人：
NEMOTO Minoru
金额：
$ 1.34万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

It was shown that the analytical electron microscope equipped with an energy dispersive X-ray spectrometer(AEM-EDS)is useful for the evaluation of microstructure-controlled materials. 1. Generalization of AEM-EDS method. (1) It was recognized that the errors in k factors were larger with use of the standard bulk specimens than the standard thin-film specimens because the S/N ratio is smaller for the former. (2) A new form of the extrapolation method was presented.It permitted the analysis of a region equivalent to a focused beam size or of a specimen with a uniform thickness. (3) A rapid processing for X-ray absorption correction was presented.This involved use of the extrapolation method assisted by a computer-based system for analytical electron microscopy with a field emission gun. 2. Applications of AEM-EDS to microstructure-controlled materials. (1) The volume fraction of particles which is an important parameter for the strengthening of alloys containing fine dispersion of particles was determined by AEM-EDS.The differential X-ray absorption method was shown to be applicable to the thickness measurement of the two types of intermetallic compounds,Ni_3(Al,Ti)and TiAl,containing finely dispersed precipitate particles. (2) Phase equilibria between the gamma and gamma' phases in Ni-base Ni-Al-Ta alloys were studied.The chemical compositions of the gamma and gamma' phases in the two-phase alloys were determined by AEM-EDS.From the composition,it was possible to obtain the tie-lines for the gamma and gamma' phases and also the partitioning coefficients of Ta in the gamma' phase. (3) Observation and microanalysis were conducted across the interfaces of the diffusion couples,Ni/Ni_3Al and Ni_3Al/ NiAl.It was shown that the interdiffusivities obtained by AEM-EDS are consistent with those by an electron probe microanalyzer(EPMA).It was then demonstrated that the AEM-EDS is suitable for the diffusivity measurement at lower annealing temperatures.

结果表明，配有能量色散X射线能谱仪(AEM-EDS)的分析电子显微镜对微观结构可控材料的评价是有用的。1.AEM-EDS方法的推广。(1)由于S/N比较小，采用标准块体试件的k因子误差大于标准薄膜试件。(2)提出了一种新的外推方法，它可以分析等效于聚焦光束大小的区域或具有均匀厚度的试件。(3)提出了一种X射线吸收校正的快速处理方法，包括使用计算机辅助的场发射枪分析电子显微镜系统的外推方法。2.AEM-EDS在微观结构控制材料中的应用(1)用AEM-EDS法测定了颗粒弥散细小的合金强化过程中的一个重要参数--颗粒体积分数。差示X射线吸收法适用于含有弥散细小颗粒的Ni_3(Al，Ti)和TiAl两种金属间化合物的厚度测量。(2)研究了镍基Ni-Al-Ta合金中伽马和伽马‘相之间的相平衡，用AEM-EDS测定了两相合金中伽马和伽马’相的化学成分，由此可以得到伽马和伽马‘相的连接线以及Ta在伽马’相中的分配系数。(3)对扩散偶Ni/Ni_3Al和Ni_3Al/NiAl的界面进行了观察和微观分析，结果表明，AEM-EDS测量的扩散系数与电子探针(EPMA)测量的结果基本一致，证明了AEM-EDS适用于较低温度下的扩散系数测量。