EAGER: Investigation of Environmental Effects on the Fatigue Degradation Properties in Metallic Nanostructures

本研究的目的是对金属纳米结构在非惰性环境中的疲劳退化特性有一个基本的认识。本研究的具体研究目标是开发一种利用微机电系统（MEMS）器件精确测量纳米结构在非惰性环境下的疲劳性能的实验技术，并研究尺寸和环境对金属纳米结构应力寿命疲劳曲线和疲劳裂纹扩展速率的影响。该方法的新颖之处在于使用电（电阻）测量来推断结构变化，例如裂缝，而不需要现场SEM/TEM能力（测试将在环境室中进行）。本研究将解决关于在纳米级器件中使用金属纳米结构的未探索的可靠性问题；这些问题最终可能会限制它们的成功商业化。深入了解纳米材料的降解特性及其对尺寸和环境的依赖关系，是确保采用新兴纳米技术制造的器件具有适当结构可靠性的基础。拟议研究的教育广泛影响在于有机会促进来自科学、技术、工程和数学（STEM）领域代表性不足群体的高中生的动机、学习和学业成功，并发展高中教师的教学技能。公团计划与高中教师一起，以9、10年级的高中学生为对象，开发以“工程材料断裂”为主题的暑期强化课程。

TECHNICAL SUMMARYThe goal of the proposed research is to gain a fundamental understanding on the fatigue degradation properties of metallic nanostructures in non-inert environments. The specific research objectives of the proposed research are to develop an experimental technique using microelectromechanical system (MEMS) devices to accurately measure the fatigue properties of nanostructures in non-inert environments and to investigate the size and environmental effects on the stress-life fatigue curves and fatigue crack growth rates in metallic nanostructures. The novelty of the approach is to use electrical (resistance) measurements to infer structural changes, such as cracking, without the need for in-situ SEM/TEM capability (testing will instead take place in an environmental chamber).NON-TECHNICAL SUMMARYThis research will address unexplored reliability issues regarding the use of metallic nanostructures in nanoscale devices; such issues may ultimately limit their successful commercialization. A thorough understanding of the degradation properties and their dependence on size and environment is fundamental to ensure proper structural reliability of devices fabricated with emerging nanotechnologies. The educational broad impact of the proposed research lies in the opportunities to promote motivation, learning and academic success of high school students from underrepresented groups in the fields of Science, Technology, Engineering and Mathematics (STEM), and to develop the teaching skills of high school teachers. The PI intends to develop, with high school teachers, a summer enrichment program dedicated to the fracture of engineering materials and targeted for high school students in grades 9 and 10.