Nanoscale Mechanics of Bulk Amorphous Metals

大块非晶态金属的纳米力学？P.M.Voyles和D.S.Stone本项目的目标是了解大块非晶态金属的结构-性质关系。宽带纳米压痕蠕变将被用来测量选定合金在约束条件下的塑性变形，这些约束条件抑制了低应变下的破坏。塑性变形激活体积和激活能将从5-6个数量级的应变率蠕变数据中得到。基于电子纳米衍射空间涨落的涨落显微镜将被用来测量相同合金中的纳米结构。将蠕变数据和组织数据进行比较，可以揭示结构是如何控制变形的，可能是通过控制剪切相变区的大小、临界应变和密度。块状非晶金属是一种新的金属合金。它们的特殊性能，如硬度高于传统钢，但密度较低，抗拉强度高，屈服强度高，弹性极限高，耐腐蚀性能优异，在结构材料或生物医学植入物和工具方面具有令人兴奋的应用前景。如果能够理解并最终在原子和纳米尺度上控制塑性变形，这些应用将会受益，这是该项目的长期目标之一。该项目还将促进工程学教育，让工程学领域历来代表性不足的群体的本科生参与最前沿的工程学研究，并通过可公开访问的网络数据库传播最前沿的电子显微镜材料表征的方法和实例。

Abstract for ?Nanoscale Mechanics of Bulk Amorphous Metals?P. M. Voyles and D. S. StoneThe goal of this project is to understand structure-property relationships in bulk amorphous metals. Broadband nanoindentation creep will be used to measure plastic deformation of selected alloys under constrained conditions which suppress failure at low strain. The activation volume and activation energy of plastic deformation will be derived from creep data covering 5-6 orders of magnitude in strain rate. Fluctuation microscopy, which is based on spatial fluctuations in electron nanodiffraction, will be used to measure the nanometer-scale structure in the same alloys. Comparing the creep data and structure data should reveal how structure controls deformation, perhaps through controlling the size, critical strain, and density of shear transformation zones.Bulk amorphous metals are a new class of metal alloys. Their exceptional properties, such as hardness greater than conventional steels, but at lower density, high tensile strength, high yield strength, high elastic limit, and excellent corrosion resistance, point to exciting applications as structural materials or in biomedical implants and tools. Those applications will benefit if plastic deformation can be understood and eventually controlled at atomic and nanometer length scales, which is one of the long-term goals of this project. This project will also promote engineering education by involving undergraduates from groups historically underrepresented in engineering in forefront engineering research, and by disseminating methods and examples in forefront electron microscopy characterization of materials via a publicly accessible web database.