New Intermetallic Strengthened Cobalt Alloys

该奖项是根据2009年美国复苏和再投资法案(公法111-5)资助的。技术摘要：最近发现在Co-Al-W三元系统中存在稳定的L12相场，这为开发一类新的高温合金提供了一条途径。这项研究计划将建立对Co-Al-W三元及更高阶系单晶的凝固、相平衡和高温力学性能的基本理解。为此，将通过以下途径实现：(1)选择一系列Co-Al-W基合金，目的是扩大两相场，提高固溶体温度和/或改变析出物的断层能；(2)单晶的生长；(3)凝固偏析的表征以及这些材料易于凝固不稳定的倾向；(4)微观组织和析出物形态的表征；(5)高温强度和蠕变抗力的测量；(6)变形机制的透射电子显微镜研究。这项研究的更广泛影响是确定了新的高温合金，这些合金有可能取代镍基合金，并通过大幅提高性能和能源效率来改变广泛的航空、空间和能源发电系统。非技术摘要：提高利用结构、承重材料的各种先进工程系统的能效是未来经济健康和社会福祉的基本要素。更高温度/更轻重量的材料是提高航空、空间、汽车和发电系统性能和效率的途径。该计划将研究一类新的高温合金，这种合金以钴为基础，并用新发现的金属间化合物相的高体积分数进行强化。为了评估这些新材料的潜力，将生长单晶，并将表征关键的高温物理和机械性能。研究生和本科生将参与这一研究计划，该计划将得到来自GE Energy、劳斯莱斯、GE航空和波音的行业资源的补充。该项目还将为ASM教师S高中科学教师夏令营提供技术资源，该夏令营自2001年以来每年在密歇根大学材料科学与工程系举办。

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.