Nanoscale Mechanics of Bulk Amorphous Metals

抽象为？大块非晶金属的纳米尺度力学P. M. Voyles和D. S.这个项目的目标是了解大块非晶金属的结构-性能关系。 宽带纳米压痕蠕变将用于测量在抑制低应变下失效的约束条件下选定的合金的塑性变形。 塑性变形的激活体积和激活能将从覆盖5-6个数量级的应变速率的蠕变数据导出。 波动显微镜，这是基于电子纳米衍射的空间波动，将用于测量相同的合金中的纳米级结构。 比较蠕变数据和结构数据应该可以揭示结构是如何控制变形的，也许是通过控制剪切转变区的尺寸、临界应变和密度。大块非晶金属是一类新的金属合金。 它们的特殊性能，如硬度大于传统钢，但密度较低，高拉伸强度，高屈服强度，高弹性极限和优异的耐腐蚀性，指出令人兴奋的应用作为结构材料或生物医学植入物和工具。 如果能够理解塑性变形并最终在原子和纳米长度尺度上进行控制，这些应用将受益，这是该项目的长期目标之一。 该项目还将促进工程教育，让来自历史上在工程领域代表性不足的群体的本科生参与前沿工程研究，并通过公开访问的网络数据库传播材料前沿电子显微镜表征的方法和实例。

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.