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

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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.