Microstructure and Mechanical Behavior of FeNiMnAl Eutectic Alloys

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This Award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).TECHNICAL SUMMARYThe objective of this proposal is to understand and model the microstructure and deformation mechanisms controlling the strength and ductility as a function of temperature and strain rate for different lamellar spacings in a recently-discovered, high-strength, ductile, two-phase, FeNiMnAl eutectic alloy, Fe30Ni20Mn35Al15, using state-of-the-art techniques. At Dartmouth College, work will focus on microstructural characterization, mechanical testing, determining deformation mechanisms and modeling. Microchemical measurements using a LEAP and microstructural characterization of interfaces using a Hitachi 3300 HRTEM will be performed through collaborations at the Oak Ridge National Laboratory. While the work is focused on a particular eutectic alloy, it is expected that the resulting experimental observation-based modeling will have applicability to eutectic alloys as a whole providing a transformative paradigm for improving the strength and ductility of polycrystalline lamellar microstructures.NON-TECHNICAL SUMMARYThe aim of this project is to understand the deformation mechanisms controlling the strength and ductility of a recently-discovered, high-strength, ductile, FeNiMnAl alloy, a material that could potentially be used in high-temperature power plant applications. The work will use a variety of advanced materials characterization techniques both at Dartmouth College and at the Oak Ridge National Laboratory. The project will also evaluate existing models of strength and ductility of similar materials and develop new models based on the experimentally-observed deformation mechanisms with a view to developing a paradigm for how to improve the strength and ductility of both FeNiMnAl alloys and alloys with similar microstructures. The results of the research will be published in refereed journals, presented at conferences, and documented on a web page. The project will lead to the training of both a Ph.D. student and several undergraduates. In spring 2008, Dartmouth's Thayer School of Engineering launched a Ph.D. "Innovation Program" designed to teach students the skills needed to be effective in the innovation process. Innovation fellowship funding is available to support the student's research after the 3rd year of their Ph.D. The undergraduates, who will integrate closely with the Ph.D. student's studies, will be supported by Dartmouth's nationally-honoured Women In Science Project or Dartmouth Presidential Scholarships. In addition, a DOD/NSF-funded summer student will work on the project each year.