NIRT: Uncovering Deformation Mechanisms of Nanostructured Materials

该项目是一项合作的跨学科研究，旨在阐明纳米结构材料的变形和断裂机制并对其进行建模。这些研究对于与机械性能密切相关的下一代MEMS、NEMS、磁性和超硬薄膜以及微/纳米器件的可靠性具有重要意义。一个主要的目标是彻底和扎实地了解在纳米材料中工作的变形机制。这项研究是专门为探索材料在纳米尺度上的机械响应而设计的。新设计的原位电子显微镜观察和微观样品拉伸和瞬变实验将被用来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。将根据实验结果开发包含物理模型的多尺度有限元计算。这些模型以及纳米晶材料中具有原子性晶界描述的自适应网格化和内聚性元素将被用于开发预测纳米晶颗粒汇编的集体宏观响应的模型。参与该项目的本科生、研究生和博士后研究员将得到共同建议。将组成两个平行的团队，每个团队包括一名博士后、研究生和一名本科生研究助理，并将在所有级别发展指导技能。拟议研究的压倒一切的智力挑战是开发一种基于科学的方法，用于测量、描述和模拟纳米级或接近纳米级的变形和断裂过程。这一结果将在MEMS、NEMS和其他使用磁性和超硬薄膜的技术中得到应用。该项目汇集了纳米晶体材料合成、电子显微镜、微量样品测试以及自适应网格化和内聚元素建模等方面的专业知识。强调团队合作的重要性，并将教育所有参与者在纳米级的跨学科、多尺度的环境中工作。

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.