New Intermetallic Strengthened Cobalt Alloys

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This Award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).TECHNICAL SUMMARY:The recent discovery of the existence of a stable L12 phase field in the ternary Co-Al-W system suggests a path for development of a new class of high temperature alloys. This research program will establish a fundamental understanding of solidification, phase equilibria and high temperature mechanical properties of single crystals of ternary Co-Al-W and higher order systems. This will be accomplished by: (1) selection of a series of Co-Al-W based alloys with the objectives of expanding the two phase γ - γ' field, increasing solvus temperatures and/or modifying precipitate fault energies; (2) growth of single crystals; (3) characterization of solidification segregation and the propensity of these materials for solidification instabilities; (4) characterization of microstructure and precipitate morphology; (5) measurement of high temperature strength and creep resistance; (6) transmission electron microscopy studies of deformation mechanisms. The broader impact of this research is the identification of new high temperature alloys that have the potential to replace Ni-base alloys and transform a wide range of aviation, space and energy generation systems through substantial improvements in performance and energy efficiency.NON-TECHNICAL SUMMARY:Improvements in the energy efficiency of a wide spectrum of advanced engineering systems that utilize structural, load-bearing materials are an essential element of the future economic health and well-being of society. Higher temperature / lighter weight materials are the path to improved performance and efficiency in aviation, space, automotive and electric power generation systems. This program will investigate a new class of high temperature alloys that are based on cobalt and strengthened with a high volume fraction of a newly discovered intermetallic phase. To assess the potential of these new materials, single crystals will be grown and critical high temperature physical and mechanical properties will be characterized. Graduate and undergraduate students will participate in this research program, which will be supplemented with industry resources from GE Energy, Rolls Royce, GE Aviation and Boeing. This program will also provide technical resources for the ASM Teacher?s Camp for high school science teachers that has been hosted in the University of Michigan Department of Materials Science and Engineering yearly since 2001.