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Creep of Temperature Stabilized Nanocrystalline Metals - a High Throughput Approach

温度稳定纳米晶金属的蠕变 - 高通量方法

基本信息

批准号：
1635332
负责人：
Maarten P de Boer
金额：
$ 42万
依托单位：
Carnegie-Mellon University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2016
资助国家：
美国
起止时间：
2016-09-01 至 2019-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1635332&HistoricalAwards=false
关键词：
Creep Temperature Stabilized Nanocrystalline Metals

项目摘要

This award supports fundamental research to map nanocrystalline metal creep, for which there is limited understanding, as a function of temperature and stress. High strength metals are used to reduce weight in many structural applications including aircraft and automobile components. Typically, metals are polycrystalline materials with grain size on the order of one hundred micrometers. One of the most effective methods to increase metal strength is to reduce the grain size to the nanometer scale. Such nanocrystalline metals are extremely strong at higher temperatures but typically suffer from creep at these temperatures. Thermally stabilized nanocrystalline metals are strong candidates for improved protective coatings, electrical contacts and are of great interest in nuclear material applications. This project will be beneficial for the training of graduate and undergraduate students in mechanical property evaluation, nanofabrication, electrodeposition and electron microscopy. Outreach activities will also be performed to develop YouTube videos relating fictional super powers of comic book characters to real-life materials enhancements. A micromachined creep test platform has been developed and will be optimized. Objective one is to synthesize the first creep maps of nanocrystalline metals over a wide range of temperature and stresses. Previous work suggests that there is a threshold stress for secondary creep that scales inversely with grain size. Objective two is to investigate if this threshold stress exists and to explore its dependence on grain size. Objective three is to determine the underlying diffusion and dislocation-based mechanisms, in part through the use of transmission electron microscopy. In summary, this project endeavors to significantly improve the fundamental understanding of creep in nanocrystalline metals.

该奖项支持基础研究，以映射纳米晶金属蠕变，其中有有限的理解，作为温度和应力的函数。高强度金属在许多结构应用中用于减轻重量，包括飞机和汽车部件。典型地，金属是具有大约一百微米的晶粒尺寸的多晶材料。提高金属强度的最有效方法之一是将晶粒尺寸减小到纳米尺度。这种纳米晶体金属在较高温度下非常坚固，但通常在这些温度下遭受蠕变。热稳定的纳米晶金属是用于改进保护涂层、电接触的强有力的候选者，并且在核材料应用中具有极大的兴趣。本计画将有助于培养研究生与本科生在机械性质评估、奈米织物、电沉积与电子显微镜等方面的能力。还将开展外联活动，制作YouTube视频，将漫画人物的虚构超能力与现实生活中的材料增强相联系。微机械蠕变测试平台已经开发，并将优化。目标一是合成纳米晶金属在较宽温度和应力范围内的第一蠕变图。以前的工作表明，有一个门槛应力二次蠕变的比例与晶粒尺寸成反比。目的二是研究该阈值应力是否存在，并探讨其对晶粒尺寸的依赖性。第三个目标是确定潜在的扩散和位错为基础的机制，部分通过使用透射电子显微镜。总之，本项目致力于显著提高纳米晶金属蠕变的基本理解。