In-Situ TEM and SEM Studies of Fundamental Deformation and Failure Processes of Nano-Grained FCC Metals Using MEMS Stages

使用 MEMS 平台对纳米晶粒 FCC 金属的基本变形和失效过程进行原位 TEM 和 SEM 研究

• 批准号: 0237400
• 负责人: Ian Robertson
• 金额: $ 40万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-02-01 至 2008-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0237400&HistoricalAwards=false
• 关键词: Situ; TEM; SEM; Studies; Fundamental

This grant is on a study of the mechanical properties of nano-grained Cu, Al and Ni using MEMS stages with emphasis on in-situ testing to characterize the underlying deformation mechanisms that involve dislocation-dominated versus grain-boundary controlled as small grain sizes are approached. Another objective is to investigate the failure modes in nano-grained materials since dramatic changes are expected as the crack tip dimension becomes comparable to the grain or particle size. Understanding these processes at this length scale are important if reliable devices and new structural materials are to be constructed intelligently from these nanoscale building blocks. A major goal of the project is to use a novel microelectromechanical-based tensile test device that was designed and fabricated at the University of Illinois to measure the mechanical properties and to simultaneously observe the operative deformation and fracture process of two- and three-dimensional nanograin structures. The same device will be used in both the scanning and transmission electron microscopes, and thus it will be possible for the first time to directly correlate macroscopic mechanical properties with deformation and fracture processes in ultra-fine grained materials as a function of grain size. The aim is to investigate these aspects in FCC metals such as Cu, Al and Ni. In addition to the experimental studies, molecular dynamics simulations will be made to predict deformation mechanisms as grain size is reduced to nanometer size. The model predictions will be correlated with the experimental results.The outcome of the proposed program will provide the foundation for developing new physical-based models for predicting the mechanical response of structures and devices containing nanosized grains and particles. The grant involves graduate student participation along with outreach program that has been in place at the University of Illinois.

这项资助是用MEMS阶段研究纳米晶铜、铝和镍的力学性能，重点是原位测试，以表征潜在的变形机制，涉及位错主导与晶界控制的变形机制，当接近小的晶粒度时。另一个目标是研究纳米晶材料的失效模式，因为随着裂纹尖端尺寸变得与颗粒或颗粒尺寸相当，预计会发生巨大变化。如果要从这些纳米级的积木中智能地构建可靠的设备和新的结构材料，在这种长度范围内了解这些过程是重要的。该项目的一个主要目标是使用伊利诺伊大学设计和制造的一种新型的基于微电子机械的拉伸测试设备来测量机械性能，并同时观察二维和三维纳米颗粒结构的工作变形和断裂过程。扫描电子显微镜和透射电子显微镜将使用相同的设备，因此将首次有可能直接将宏观机械性能与超细晶粒材料的变形和断裂过程作为晶粒度的函数联系起来。目的是研究面心立方金属如铜、铝和镍中的这些方面。除了实验研究外，还将进行分子动力学模拟，以预测晶粒度减小到纳米尺寸时的变形机制。模型预测将与实验结果相关联。所提出的程序的结果将为开发新的基于物理的模型来预测包含纳米颗粒和颗粒的结构和器件的力学响应提供基础。这笔助学金涉及研究生的参与，以及伊利诺伊大学已经实施的外展计划。