Loading Metal Nanostructures Under Extreme Conditions Using Stress Waves with Rarefaction Shock Profiles

使用具有稀疏冲击曲线的应力波在极端条件下加载金属纳米结构

• 批准号: 1024353
• 负责人: Vijay Gupta
• 金额: $ 60.19万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1024353&HistoricalAwards=false
• 关键词: Loading; Metal; Nanostructures; Under; Extreme

This research project combines experimental and multi-scale modeling efforts to investigate novel deformation mechanisms occurring in metals during extremely high rates of stress and strain. In this study, nanostructured samples will be subjected to laser-generated stress waves of sub-nanosecond rise times. As a result, the material experiences 50 GigaPascals or higher stresses within 1 nanosecond. The material's response to such dynamic conditions has not been explored in detail before. The laser shock experiments will be combined with electron microscopic characterization of the same samples before and after deformation and multi-scale modeling. This approach enables direct correlation between the evolved structures and experimental parameters of pressure and strain rate. Additionally, the sample geometries are amenable to modeling and thereby allowing for a direct comparison. These studies will establish scientific underpinning for the experimentally-observed and/or simulation-predicted new deformation mechanisms and provide an atomic-scale understanding of the material stability in extreme environments. The work should help in the design of alternate energy systems and advanced armors. The combination of advanced nanofabrication and microscopy, sophisticated optics and mechanical testing, and state-of-the-art modeling strategies provides excellent interdisciplinary training for graduate students and undergraduates. To promote awareness of the research ideas: the Los Angeles Unified School District high-school students will be provided with research opportunities; research results will be integrated into the engineering curriculum; and, underrepresented groups and undergraduates will be encouraged to participate in the research activities.

该研究项目结合了实验和多尺度建模工作，以研究在极高的应力和应变速率下金属中发生的新型变形机制。在这项研究中，纳米结构的样品将受到激光产生的应力波的亚纳秒上升时间。结果，材料在1纳秒内经历50吉帕斯卡或更高的应力。材料对这种动态条件的响应以前没有详细探讨过。激光冲击实验将与变形前后相同样品的电子显微镜表征和多尺度建模相结合。这种方法使演化的结构和压力和应变率的实验参数之间的直接相关性。此外，样品几何形状易于建模，从而允许直接比较。这些研究将为实验观察和/或模拟预测的新变形机制建立科学基础，并提供对极端环境中材料稳定性的原子尺度理解。 这项工作应该有助于设计替代能源系统和先进的装甲。先进的纳米纤维和显微镜，复杂的光学和机械测试，以及最先进的建模策略的结合为研究生和本科生提供了优秀的跨学科培训。促进研究理念的意识：洛杉矶联合学区的高中学生将提供研究机会;研究成果将被纳入工程课程;并，代表性不足的群体和本科生将被鼓励参与研究活动。