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。技术概述：最近在Co-Al-W三元体系中发现了一个稳定的L12相场，这为开发一类新的高温合金指明了道路。本研究项目将建立对三元钴铝钨单晶和高阶体系的凝固、相平衡和高温力学性能的基本认识。这将通过以下方式实现：(1)选择一系列Co-Al-W基合金，以扩大两相&amp；#947；——和# 947;’场，提高溶剂温度和/或改变沉淀断层能量；(2)单晶生长；(3)凝固偏析的表征和这些材料的凝固不稳定性倾向；(4)微观组织和析出物形貌表征；(5)高温强度和抗蠕变性能的测定；(6)变形机理的透射电镜研究。这项研究的更广泛的影响是确定新的高温合金，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，改变广泛的航空、航天和能源生产系统。非技术总结：利用结构和承重材料的各种先进工程系统的能源效率的改进是未来经济健康和社会福祉的基本要素。在航空、航天、汽车和发电系统中，更高温度/更轻重量的材料是提高性能和效率的途径。该项目将研究一类新型高温合金，该合金以钴为基础，并通过新发现的金属间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，并对关键的高温物理和机械性能进行表征。研究生和本科生将参与该研究项目，并将辅以GE能源、劳斯莱斯、GE航空和波音公司的行业资源。该项目还将为ASM教师提供技术资源。从2001年开始，每年在密歇根大学材料科学与工程系举办的高中科学教师夏令营。

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.