• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Physica, C. Superconductivity and its applications >MICROSTRUCTURE ANALYSIS OF MELT-TEXTURED YBA2CU3O7-X CERAMICS BY POLARIZED LIGHT MICROSCOPY
【24h】

MICROSTRUCTURE ANALYSIS OF MELT-TEXTURED YBA2CU3O7-X CERAMICS BY POLARIZED LIGHT MICROSCOPY

机译：偏光显微镜对YBA2CU3O7-X熔体陶瓷的微观结构分析

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In this paper the microstructure features of melt-textured YBa2Cu3O7-x (123) such as observed phases, grain boundaries, macro- and microcracking and twin structure are characterized. We have revealed subgrains of rectangular shape within 123 grains in the extinction orientation of the ''c''-axis with respect to the vector of polarized light. Segments of boundaries are parallel or perpendicular to the a-b-plane, having maximum occurrence of tilting angle at 6 degrees, they are not wetted by secondary phases and not preferentially cracked. It has been shown that the lines parallel to the a-b-plane are microcracks formed at the tetragonal-orthorhombic (T-O) transition due to the difference in thermal expansion coefficients between 123 and Y2BaCuO5 (211) phases. The microcracking phenomenon obeys the model devised for the multiple failure of a fiber composite under uniaxial tension resulting in a linear relationship between microcrack spacing and 211 particle size or the reciprocal value of 211 volume fraction. A residual tensile stress of 290 MPa in the ''c''-direction was estimated on the basis of the 123 fracture toughness. Oxygenation of the melt-textured samples was shown to be a combination of oxygen volume diffusion, microcracking and penetration of oxygen through the cracks. A new secondary phase having a composition close to Ba2Cu5Ox has been found. A lower 211 interparticle distance generally leads to lowering of twin spacing. [References: 56]
机译：在本文中，表征了熔融织构的YBa2Cu3O7-x（123）的微观结构特征，例如观察到的相，晶界，宏观和微裂纹以及孪晶结构。我们已经揭示了相对于偏振光矢量在``c''轴消光方向上123个晶粒内矩形的亚晶粒。边界段平行于或垂直于a-b平面，最大倾斜角度为6度，它们不会被第二相润湿，也不会发生裂纹。已经表明，平行于a-b平面的线是由于123和Y2BaCuO5（211）相之间的热膨胀系数不同而在四方斜方晶（T-O）过渡处形成的微裂纹。微裂纹现象遵循为纤维复合材料在单轴张力下多次破坏而设计的模型，该模型导致微裂纹间距与211粒度或211体积分数的倒数之间呈线性关系。根据123断裂韧性估算出在``c''方向上的290 MPa残余拉应力。熔融织构样品的充氧表现为氧气体积扩散，微裂纹和氧气穿过裂纹的结合。已经发现了具有接近Ba 2 Cu 5 O x的成分的新的第二相。较低的211粒子间距离通常导致孪晶间距的减小。 [参考：56]

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号