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High-Temperature High-resolution Electron Microscopy by Image Recording

通过图像记录进行高温高分辨率电子显微镜

基本信息

批准号：
61850117
负责人：
HIRABAYASHI Makoto
金额：
$ 5.76万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

项目摘要

Atomic-scale observations by teansmission electron microscopy (TEM) have widely been applied in materials science, but still restricted for static scenes at ambient temperature. It is necessarily important, therefore, to make efforts for extending this method at higher and lower temperatures. In this project, we aimed to develop an in-situ observation system of high resolution electron microscopy at elevated temperatues for studying dynamical behaviors of structural phase transformations.A 200 KV electroc mictoscope (JEOL-200 CX) is modified installing a double-tilt top-entry gonimeter which is capable to heat a specimen up to about 800゜C in combination with a newly designed pole-piece with C_s=1.0mm. A computer-aided system is utilized for recording dynamical changes of high resolution imager, and for calculating simulation images to analyze the observations.Following experiments were carried out to testify the capability of this apparatus.(1) Incommensurate-commensurate phase transformation of Ag_3Mg: When an alloy Ag_3Mg with non-integral period M=1.83 is heated in the microscope at about 320゜C, dynamical motion of discommensuration lines can be recorded for consecutive 2-3 hours with the use of a side-entry goniometer.(2) Formation processes of CuAuII in CuAuI: Nucleation and growth processes of antiphase boundaries of the long-period superstrecture CuAuII in the matrix of CuAuI are observed in situ at about 300゜C using the top-entry gonimeter and the recording system.(3) Ordering processes of Ni_4Mo: High resolution images on Ni_4Mo at an early stage of ordering form the disordered structure are observed inrterpreted well using the image-analysis system.

透射式电子显微镜的原子尺度观测在材料科学中得到了广泛的应用，但仍然局限于常温下的静态场景。因此，努力在更高和更低的温度下推广这种方法是必要的。为了研究结构相变的动力学行为，我们研制了一套高温高分辨电子显微镜原位观察系统。对200KV电子显微镜(JEOL-200CX)进行了改装，安装了双倾斜顶部入口式测温仪，可将样品加热到约800゜C，并结合新设计的C_S=1.0 mm的极片。利用计算机辅助系统记录高分辨率成像仪的动态变化，并计算模拟图像对观测结果进行分析。(1)Ag_3 Mg的非公度相变：当在大约320゜C的显微镜下加热非整周期为M=1.83的Ag_3 Mg时，(2)CuAuII在CuAuI中的形成过程：利用顶部入口式测角仪和记录系统在300゜C左右原位观察到了CuAuI中长周期超结构CuAuII反相界的形核和生长过程。(3)Ni_4Mo的有序化过程：利用图像分析系统很好地解释了有序化初期Ni_4Mo上的高分辨率图像。