Constitutional and/or Thermal Vacancies in some Intermetallic Compounds

某些金属间化合物中的结构空位和/或热空位

基本信息

批准号：
08455289
负责人：
SHIRAI Yasuharu
金额：
$ 4.42万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08455289/
关键词：
atomic vacancy positron annihilation intermetallic compound lattice defects 構造欠陥

项目摘要

Nonstoichiometry of intermetallics may give rise to the existence of constitutional defects such as atoms occupying atomic sites of a sublattice other than its own sublattice (antisite atoms) or vacancies of deficient atomic species (constitutional vacancies). Such structural defects and their properties in intermetallics, which depend on nonstoichiometry, have been studied by positron annihilation methods.Positron annihilation methods are very sensitive to vacancies and small vacancy clusters which are quite difficult to be studied by other techniques. Positron studies of constitutional defects in some intermetallics have been carried out in this work. In-situ measurements of thermal equilibrium defects and studies of non-equilibrium defects on some intermetallics have been also done. The vacancy formation and migration properties in some important intermetallic componds have been directly observed by the positron-annihilation lifetime method.The conventional positron-lifetime measurement, however, is difficult to be carried out at high temperatures. In order to achieve in-situ studies of given materials at high temperatures more easily, a new beta^+_<-gamma> coincidence lifetime spectrometer using energy-selected fast-positron beam has been constructed by the author's group. The new positron apparatus will become a very powerful tool to study lattice defects at high temperatures in refractory materials.

金属间学的非缩放计量法可能会导致存在构成缺陷的存在，例如占据了sublattice的原子位点的原子，而不是其自身的sublattice（反静脉原子）或缺乏原子种类的空位（宪法空位）。这种结构缺陷及其在金属层中的特性依赖于非构思计量法，已通过正电子歼灭方法研究了。Positronan灭方法对空位和较小的空位簇非常敏感，这些方法很难被其他技术研究。在这项工作中，已经对某些金属层中的宪法缺陷进行了正电子研究。也已经完成了对某些金属层的非平衡缺陷的热平衡缺陷的原位测量。在某些重要的金属间中，空位的形成和迁移特性已通过正电子通知寿命方法直接观察到。但是，在高温下很难进行常规的千篇一律测量。为了更容易地在高温下对给定材料进行原位研究，使用了作者组建立了使用能量选择的快速稳定束的新的beta^+_ <-gamma>巧合寿命光谱仪。新的正电子设备将成为在难治性材料中高温下研究晶格缺陷的非常强大的工具。