Nanomechanics on deformation processes in nanocrystalline materials

纳米晶材料变形过程的纳米力学

• 批准号: 0625733
• 负责人: Scott Mao
• 金额: --
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-10-01 至 2011-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0625733&HistoricalAwards=false
• 关键词: Nanomechanics; deformation; processes; nanocrystalline; materials

Nanomechanics on deformation processes in nanocrystalline materialsPI: Scott X. Mao, Department of Mechanical Engineering and Materials Science, University of PittsburghNanocrystalline (nc) materials exhibit ultra-high yield strength, superior wear resistance and superplastic deformability. In extremely low grain size range (less than 20 nm), a reduction of yield strength with decreasing grain size has been found. This project focuses on discovery of deformation processes in nc materials with extremely low grain size through critical nanomechanical experiments: 1) in-situ dark field transmission electron microscope (TEM), 2) in-situ high resolution TEM and 3) in-situ nano beam electron diffraction. It will produce new insights regarding unique deformation process in nc materials such as GB sliding, stress induced grain agglomeration and lattice/GB dislocation dynamics. Hence, direct evidence on plastic deformation processes in nc materials will be provided. It is expected to find "strongest grain size" relationship with its individual grain behavior. The research on novel in-situ experiments is expected to result in a direct impact on nanoscale experimental mechanics and nanomaterials development. Furthermore, the project will integrate research and education by (i) providing training for graduate and undergraduate students, and education through graduate students' participation in DOE national laboratories, (ii) course development in "nanomechanics and nanomaterials" and (iii) increased participation of underrepresented groups into the research through current Minority Engineering Mentoring Program in University of Pittsburgh. The proposed novel experimental technique will add new capabilities to the multi-user facilities at the University of Pittsburgh and the National Center for Electron Microscopy in Lawrence Berkeley Laboratories, which is open to all US universities.

纳米晶体材料的纳米力学有关变形过程：匹兹堡大学机械工程与材料科学系Scott X. Mao，匹兹堡大学材料（NC）材料具有超高产量强度，出色的磨损耐药性和超塑性性不良性。在极低的晶粒尺寸范围（小于20 nm）中，发现差异降低晶粒尺寸的屈服强度。该项目的重点是通过关键的纳米力学实验发现具有极低晶粒尺寸的NC材料中的变形过程：1）原位深色场传输电子显微镜（TEM），2）静脉内高分辨率TEM和3）原位纳米束束电子衍射。它将在NC材料（例如GB滑动，应力诱导的谷物团聚和晶格/GB脱位动力学）中产生有关独特变形过程的新见解。因此，将提供有关NC材料中塑性变形过程的直接证据。预计它将发现与其个体谷物行为的“最强的晶粒大小”关系。关于新型现场实验的研究有望直接影响纳米级实验力学和纳米材料的发展。此外，该项目将通过（i）为研究生和本科生提供培训，以及通过研究生参与DOE国家实验室的教育，（ii）“纳米力学和纳米材料”的课程发展，（iii）通过在现任少数群体中，通过在现任少数群体中培养的群体参与，通过现有少数派的研究，而不是现有的少数群体工程培训计划。拟议的新型实验技术将为匹兹堡大学的多用户设施和劳伦斯·伯克利实验室的国家电子显微镜中心增加新功能，该设施向所有美国大学开放。