U.S.-Mexico Cooperative Research on Grain Boundary Phenomena in Oriented Bicrystals Subjected to High Tempature Fatigue

美墨合作研究高温疲劳定向双晶晶界现象

• 批准号: 8702092
• 负责人: Julia Weertman
• 金额: $ 0.78万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-08-15 至 1990-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8702092&HistoricalAwards=false
• 关键词: U.S.; Mexico; Cooperative; Research; Grain

This award supports the participation of Julia R. Weertman of Northwestern University in a program of joint research with Jose G. Cabanas of the Instituto Polytecnico Nacional of Mexico with the goal of improving our understanding of fatigue in metals and alloys. The experience of the Northwestern University research group in the study of micro-damage at grain boundaries, in the growth of bicrystalline materials for these studies, and in techniques for high-temperature fatiguing, will be combined with the experience at the Mexican institution in scanning and transmission electron microscopy. Single or bicrystalline copper will be grown, cut in predetermined orientations, and fatigued, at Northwestern. Selected-area channeling studies using a scanning electron microscope, and other analyses using transmission electron microscopy, will be performed at the Instituto Polytecnico Nacional to study the interdependence in fatigued material of grain boundary migration and sliding, cavitation, and dislocation structure in the region near where cavitation occurs. From these measurements light should be thrown on the relationship between cavities and dislocation structure, on the migration of grain boundaries, and the dynamics of void growth. Fatigue in metals and alloys, and the relationship of fatigue failure to microscopic voids and other defects in materials particularly as they occur at grain boundaries, are of increasing importance as more is asked of modern materials. In order to facilitate the performance of controlled experiments on grain-boundary effects, "model grain boundaries" which are isolated from properly oriented bicrystals, may be used. After fatiguing under controlled conditions, scanning electron microscopy channeling studies of crystalline orientation and perfection and transmission electron microscope investigation of the boundaries themselves can give an indication of the motion of grain boundaries and the relationship of this motion to micro-defects related to the fatigue. The Northwestern University principal investigator is an expert in the growth and orientation of such bicrystals while the Mexican collaborator has complementary expertise in specialized electron microscopy. This research should help answer certain fundamental questions regarding intergranular damage produced by high-temperature fatigue, and thereby contribute to the development of materials suitable for high-stress use in high-temperature environments.

该奖项支持Julia R.韦特曼 美国西北大学的一项联合研究计划与何塞G。 墨西哥国立理工学院的小屋， 提高我们对金属和合金疲劳的理解。 的 西北大学研究小组的研究经验 在双晶生长过程中， 这些研究的材料，以及高温技术 疲劳，将结合在墨西哥的经验， 扫描电子显微镜和透射电子显微镜。单个 或双晶铜将生长，切割成预定的形状， 在西北方向，疲惫不堪。 选区 使用扫描电子显微镜进行沟道研究， 使用透射电子显微镜进行分析，将在 国家理工学院研究 晶界迁移和滑动的疲劳材料， 空穴和位错结构在附近的区域， 发生气穴现象。 根据这些测量结果， 空洞与位错结构的关系， 晶界的迁移和空洞生长的动力学。 金属和合金的疲劳以及疲劳失效的关系 涉及材料中的微观空隙和其它缺陷， 它们发生在晶界，随着越来越多的 现代材料的要求。 为了方便演出 晶界效应的受控实验，“模型晶粒 与适当取向的双晶体隔离的“边界”可以 被利用 在受控条件下疲劳后，扫描 晶体取向的电子显微镜沟道研究， 完整性和透射电子显微镜研究 边界本身就能指示出晶粒的运动 边界以及这种运动与微缺陷的关系 与疲劳有关。 西北大学校长 调查员是这样的增长和方向的专家 墨西哥合作者拥有互补的专业知识， 专业的电子显微镜。 这项研究应该有助于回答 关于晶间损伤的一些基本问题 高温疲劳，从而有助于 开发适用于高应力环境的材料， 高温环境。