NIRT: Uncovering Deformation Mechanisms of Nanostructured Materials

本项目是一项跨学科合作研究，旨在阐明和模拟纳米结构材料的变形和断裂机制。这些研究对于下一代MEMS、NEMS、磁性和超硬薄膜以及微/纳米器件的可靠性非常重要，因为这些器件与它们的机械性能密切相关。一个主要的目标是获得一个彻底的和坚实的理解操作变形机制在纳米尺度材料操作。这项研究是专门设计来探测纳米尺度上材料的机械响应的。新设计的原位透射电镜观察和微样品拉伸和瞬态实验将用于揭示和表征高纯气相和电沉积纳米结构薄膜的主要变形和断裂机制。包含物理模型的多尺度有限元计算将基于实验结果进行开发。这些模型以及自适应网格划分和具有纳米晶体材料晶界原子描述的内聚元素将用于开发模型来预测纳米晶体的集体宏观响应。参与本项目的本科生、研究生和博士后将共同指导。将成立两个平行的团队，每个团队包括一名博士后、一名研究生和一名本科生研究助理，并在各个层面发展指导技能。提出的研究最重要的智力挑战是开发一种基于科学的方法来测量、描述和模拟纳米或接近纳米长度尺度的变形和断裂过程。该结果将应用于MEMS， NEMS和其他使用磁性和超硬薄膜的技术。该项目汇集了纳米晶体材料合成、电子显微镜、微样品测试、自适应网格划分和内聚元素建模等专业知识的协同组合。强调团队合作的重要性，所有参与者都将接受在纳米尺度的跨学科多尺度环境中工作的教育。

This project is a collaborative inter-disciplinary research to elucidate and model the deformation and fracture mechanisms of nanostructured materials. These studies are important for the reliability of next-generation MEMS, NEMS, magnetic and ultra-hard films, and micro/nano devices, in general, that are closely tied to their mechanical performance. A major objective is to obtain a thorough and solid understanding of operative deformation mechanisms operative in nanoscale materials. The study is specifically designed to probe the mechanical response of materials at nano-scales. Novel designs for in situ TEM observations and microsample tensile and transient experiments will be used to uncover and characterize the dominant deformation and fracture mechanisms in high purity vapor and electro-deposited nanostructured thin films. Multi-scale finite element calculations containing physical models will be developed based on the experimental findings. These models along with adaptive meshing and cohesive elements with atomistic descriptions of grain boundaries in nanocrystalline materials will be used to develop models to predict the collective macroscopic response of a compilation of nanocrystalline grains. The undergraduate and graduate students and post-doctoral fellows engaged in this project would be co- advised. Two parallel teams, each including a post-doc, graduate student and an undergraduate research assistant, will be formed and mentoring skills will be developed at all levels.The overriding intellectual challenge of the proposed study is to develop a science based methodology for measuring, describing and modeling deformation and fracture processes at or near nanometer length scales. The results will have application in MEMS, NEMS and other technologies where magnetic and ultra-hard films are used. This project brings together a synergistic combination of expertise on the synthesis of nanocrystalline materials, the electron microscopy, microsample testing, and adaptive meshing and cohesive element modeling. The importance of teamwork is emphasized and all participants will be educated to work in an inter-disciplinary multi-scale environment at the nano scale.