权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Atom-level analysis of structures of lattice defects in materials

材料晶格缺陷结构的原子级分析

基本信息

批准号：
62460187
负责人：
SAKURAI Junji
金额：
$ 4.48万
依托单位：
HIROSHIMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

Some materials newly found as well as recently synthesized were examined by not only the X-ray or electron diffraction methods but also the electron microscopy.High-Tc superconducting materials, Y-Ba-Cu-Oxide: Observations of the microstructures by high-resolution electron microscopy have pointed that the twin-lamellar structures are also important for the quality of the supercon-ductivity. Bi-Ca-Sr-Cu-Oxide: The conditions under which more than 70% of the 107K-class superconducting materials are synthesized without Pb in the pellets of the oxise are determined. The Bi-concentration in the materials is unexpectedly high.Shape memory alloy, Ti-Ni: Three features in the diffuse scattering have been confirmed. Diffuse maxima locate near n/7, 2n/7, 3n/7 (n an integer) and equivalent positions. A ring-type diffuse scattering is observed in the h01 reciprocal plane and the distribution is found to be reversively changed at low temperatures. All the diffuse scattering disappear in the electron diffraction pattern when the electron beam is incident parallel to the <111>-direction.[(GaAS)_4/(AlAs)_4]_<150>-Superlattice: The period of the superlattice is not the same throughout the specimen, and fluctuates between eight and nine times of the atomic layer. B19-ordered alloy: Below the phase transition temperature, an interesing domain structure has been discovered. The micro-structures are interpreted by the existence of various types of disclinations. Laves phase alloys: Boundary structure of layer structures are analyzed by proposing an extention of the concept of the CSL-model.Ce-intermetallic compounds: Various intermetallic compounds containing Ce, have been investigated at low temperatures. Anomalous temperature dependences of the electric resistivities as well as the thermo-electric power have been discovered. Anomaly in the thermal expansion coeffeicients and latticc transformations have also been detected.

对一些新发现的和新近合成的材料，不仅用X射线衍射和电子衍射方法，而且用电子显微镜进行了研究。高Tc超导材料Y-Ba-Cu氧化物：用高分辨电子显微镜观察其微观结构，指出孪晶层结构对超导电性的质量也是重要的。Bi-Ca-Sr-Cu-氧化物：确定了在氧化物芯块中不含Pb的条件下，70%以上的107 K级超导材料得以合成。Bi在材料中的浓度出乎意料地高。形状记忆合金，Ti-Ni：漫散射中的三个特征已被证实。扩散最大值位于n/7、2n/7、3 n/7（n为整数）附近及相当位置。在h 01倒易面观察到环形漫散射，发现在低温下分布发生反向变化。当电子束平行于入射方向入射时，电子衍射图样中的漫散射全部消失<111>。[（GaAS）_4/（AlAs）_4]_<150>-超晶格：超晶格的周期在整个样品中并不相同，并且在原子层的八到九倍之间波动。B19有序合金：在相变温度以下，发现了有趣的畴结构。显微结构的解释是存在各种类型的向错。Laves相合金：通过提出CSC模型概念的扩展，分析了层结构的边界结构。Ce金属间化合物：各种含有Ce的金属间化合物在低温下进行了研究。发现了电介电常数和热电功率的反常温度依赖性。在热膨胀系数和晶格转变中也发现了反常现象。