Fundamental mechanisms of removal of stacking fault tetrahedra by mobile low energy boundaries

移动低能边界去除堆垛层错四面体的基本机制

• 批准号: 1304101
• 负责人: Xinghang Zhang
• 金额: $ 44.89万
• 依托单位: Texas A&M Engineering Experiment Station
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1304101&HistoricalAwards=false
• 关键词: Fundamental; mechanisms; removal; stacking; fault

TECHNICAL SUMMARY: The objective of this work is to understand the fundamental mechanisms through which mobile twin boundaries (TBs) actively engage and rapidly remove stacking fault tetrahedra (SFTs). The ultimate goal is to design advanced metallic materials that can effectively remove SFTs at low-to-intermediate temperatures. SFTs are detrimental defects in neutron or proton irradiated structural metallic materials with face-centered-cubic structures as they can induce significant hardening and swelling. The PI will use a combination of in situ radiation and in situ nanoindentation technique to investigate the interaction of SFTs with TBs. These studies can explain the annihilation of SFTs by TBs and provide crucial information to validate annihilation mechanisms predicted by MD simulations. Also significant mobility of TBs may make them attractive candidates to remove radiation induced immobile defects, such as SFTs. NON-TECHNICAL SUMMARY:If successful, the benefits of this research will include discovery of important criteria for the design of swelling resistant structural materials for next generation nuclear reactors, and offer the basis for further exploration of physics of radiation induced twin boundary migrations. This project will provide research training to graduate and undergraduate students at Texas A&M University (TAMU). Special effort will be made to recruit female and other minority students through the "Pathway to Ph.D program" funded by TAMU. The project will also enhance the materials science and nanoengineering curricula by incorporating relevant results into classes when introducing advanced nanomaterials, and benefit the new formed Department of Materials Science and Engineering. The PI will disseminate results to a much broader audience by involving high school teachers in the research project through NSF-RET program, and attending international conferences. Collaborations with McMaster University and several DOE National Laboratories will offer graduate students summer research experience.

技术摘要：这项工作的目的是了解移动孪晶边界 (TB) 主动参与并快速消除堆垛层错四面体 (SFT) 的基本机制。最终目标是设计能够在中低温度下有效去除 SFT 的先进金属材料。 SFT 是具有面心立方结构的中子或质子辐照结构金属材料中的有害缺陷，因为它们会引起显着的硬化和膨胀。 PI 将结合使用原位辐射和原位纳米压痕技术来研究 SFT 与 TB 的相互作用。这些研究可以解释 TB 对 SFT 的湮灭，并为验证 MD 模拟预测的湮灭机制提供重要信息。此外，TB 的显着移动性可能使其成为消除辐射引起的固定缺陷（例如 SFT）的有吸引力的候选者。非技术摘要：如果成功，这项研究的好处将包括发现下一代核反应堆抗膨胀结构材料设计的重要标准，并为进一步探索辐射引起的孪晶边界迁移物理学提供基础。该项目将为德克萨斯农工大学 (TAMU) 的研究生和本科生提供研究培训。 TAMU 资助的“博士之路项目”将特别努力招收女性和其他少数民族学生。该项目还将在介绍先进纳米材料时将相关成果纳入课堂，从而加强材料科学和纳米工程课程，并使新成立的材料科学与工程系受益。 PI 将通过 NSF-RET 计划让高中教师参与研究项目以及参加国际会议，从而向更广泛的受众传播研究成果。与麦克马斯特大学和能源部几个国家实验室的合作将为研究生提供暑期研究经验。