Experimental Investigation of Microstructural Effects on Deformation and Fracture Mechanisms in Nanostructured Metallic Materials

项目摘要：纳米结构金属材料微观结构对变形和断裂机制影响的实验研究本项目将使用2009年美国复苏和再投资法案（公法111-5）提供的资金，并符合2009年3月20日白宫备忘录第2节“确保负责任的复苏法案资金支出”的要求。我还确认，作为认可的项目官员，该提案不支持《复苏法案》A部分第1604条所述的项目。该奖项的研究目的是通过实验研究微观结构对纳米结构金属材料热力学行为的影响。纳米结构金属（晶粒尺寸在数百纳米量级的金属）是一类令人兴奋的材料，它显示出同时具有强度和延展性的罕见能力。该奖项的工作将集中在通过量化晶粒和跨越晶界的全场应变的实时发展来理解这些材料的变形机制，并将该应变与原位电子背散射衍射确定的局部微观结构联系起来。该研究将利用铝、镁及其合金作为模型材料，研究两种非常不同的晶体系统在超细晶粒尺寸下的热力学响应。该奖项的实验和建模工作将大大提高我们对中等晶粒尺寸的基本力学的理解，以及我们设计和开发加工工具以定制这些材料的机械性能的能力。除了本研究的基础影响外，了解纳米结构铝和镁的变形机制对工业至关重要，因为这些金属适合超塑性成形。项目外展包括与当地学校系统的伙伴关系，涉及研究生参与调查员？他还为初高中学生创建了一个关于实验技术的网络学习模块。

PROJECT ABSTRACT: Experimental Investigation of Microstructural Effects on Deformation and Fracture Mechanisms in Nanostructured Metallic MaterialsThis proposal will be awarded using funds made available by the American Recovery and Reinvestment Act of 2009 (Public Law 111-5), and meets the requirements established in Section 2 of the White House Memorandum entitled, Ensuring Responsible Spending of Recovery Act Funds, dated March 20, 2009. I also affirm, as the cognizant Program Officer, that the proposal does not support projects described in Section 1604 of Division A of the Recovery Act. The research objective of this award is to experimentally investigate the effects of microstructure on the thermo-mechanical behavior of nanostructured metallic materials. Nanostructured metals (metals with grain sizes on the order of hundreds of nanometers) are an exciting class of materials that have shown the rare ability to be simultaneously strong and ductile. The effort in this award will focus on understanding the deformation mechanisms in these materials by quantifying the real-time development of full-field strain in grains and across grain boundaries, and relating this strain to the local microstructure as determined by in-situ electron backscatter diffraction. The research will utilize Aluminum, Magnesium, and their alloys as model materials to investigate the thermo-mechanical response of two very different crystallographic systems at ultra-fine grain sizes. The experimental and modeling efforts performed with this award will greatly enhance our understanding of the fundamental mechanics of intermediate grain sizes, and our ability to design and develop processing tools to tailor the mechanical properties of these materials. In addition to the fundamental impact of this research, understanding the deformation mechanisms in nanostructured Aluminum and Magnesium is of critical industry importance due to the suitability of these metals for superplastic forming. Project outreach includes a partnership with a local school system that involves the participation of graduate students in the investigator?s research group as Teaching Fellows, and the creation of a web-learning module on experimental techniques for middle school and high-school students.