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

项目摘要：纳米结构金属材料中微观结构对变形和断裂机制影响的实验研究本提案将使用2009年《美国复苏与再投资法案》(公法111-5)提供的资金授予，并符合2009年3月20日白宫备忘录第2节《确保负责任地使用复苏法案资金》中规定的要求。作为认知项目官员，我还确认，该提案不支持《复苏法案》A分部第1604节所述的项目。该奖项的研究目标是通过实验研究微结构对纳米结构金属材料热机械行为的影响。纳米结构金属(晶粒度在数百纳米量级的金属)是一类令人兴奋的材料，它显示出罕见的同时具有强度和延展性的能力。该奖项的工作重点是通过量化全场应变在晶内和晶界的实时发展，并将这种应变与原位电子背散射衍射确定的局部微结构相关联，来了解这些材料中的变形机制。这项研究将以铝、镁及其合金为模型材料，研究两种截然不同的晶体系统在超细晶粒尺寸下的热机械响应。此次获奖的实验和建模工作将极大地提高我们对中间颗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。除了这项研究的基本影响外，了解纳米结构铝和镁的变形机制也具有至关重要的行业意义，因为这些金属适合于超塑性成形。项目外展包括与当地学校系统建立伙伴关系，让研究生作为研究员参加S研究小组，并为初中生和高中生创建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.