Lightweight, High Temperature Beta Gamma Alloy/Process Development for Air Frame Structure Applications Navy SBIR FY2008.1 Sol No.: Navy SBIR FY2008.1 Topic No.: N08-071 Topic Title: Lightweight, High Temperature Beta Gamma Alloy/Process Development for Air Frame Structure Applications Proposal No.: N081-071-0166 Firm: UES, Inc. 4401 Dayton-Xenia Road Dayton, Ohio 45432-1894 Contact: Young-Won Kim Phone: (937) 255-1321 Web Site: www.ues.com Abstract: Gamma titanium aluminide alloys (gamma alloys) possess the attractive combination of low density (~50% of that of superalloys) and high temperature (up to 1500�F) capability, ideal for hot airframe structure and turbine engine applications. Yet, gamma alloys have not been inserted into aerospace service due to their material and manufacturing limitations. The primary limitations include processing difficulties, requiring costly non-conventional or multi-step processing requirements, and large lamellar grains, often leading to lowered damage tolerance. We have developed a new class of TiAl-based alloys, called beta gamma, which would remove or reduce such barriers. Unlike existing gamma alloys, beta gamma alloys are designed such that the ductile beta phase is adequate at elevated temperatures (for processing) but low or negligible at the anticipated use temperatures (for performance). The alloys also feature significant grain refinement and compositional homogeneity. This program is aimed to utilize such beneficial beta-phase distribution and microstructure features to develop the process technology to produce low-cost beta gamma alloy mill products such as thin sheets and rectangular bars with potentially improved properties. These low-density (4.1g/cm3) products are expected to be used at least up to 1300�F, showing application potential for airframe and engine structures. Benefits: Expected benefits: The research proposed in Phase I would allow us to demonstrate that processing of beta gamma alloys into various mill product forms is technically very feasible at a temperature that can be easily attained in industry furnaces. Furthermore, a successful execution of Phase I Option task (low-cost direct rolling) will show the production can be even affordable. These demonstrations made using a crude rolling mill and an air furnace will provide a rolling process (parameters and conditions) window for producing even thinner and/or wider sheets, which is planned for Phase II program. In addition, the selected beta gamma alloy will show significant improvements in various attributes and properties, including strength and ductility, machinability (due to Cu and Mn additions) as well as increased resistances to oxidation and wear/erosion (due to the Nb+Mo combined effect). Another significance is that this work is the first step toward establishing a domestic fabrication capability for high temperature gamma-based beta gamma alloy bars and sheets. There is ample evidence for industrial need of these products for various (space, defense as well as commercial) applications. This work will accelerate the development of affordable engineering beta gamma alloy/process for such applications. Expected Commercial Applications: Due to their low density, high temperature capability (up to 700�C for long-term use or 800�C for short-term use), expected damage tolerance improvements and low production cost, beta gamma alloy products that can be readily produced into various forms will find their potential applications for various hot structures in air vehicles, automobile engine components (such as turbocharger and valves), and land-base turbines. In particular, beta gamma alloy sheets and bars will offer substantial potential for thin-section components in the systems for the next generation of advanced engines (UCAS-D, Long Range Strike) and even for current high performance engines (such as B2, F-35, F/A-18, and Global Hawk). The components include nozzle-section structures, TPS panels, and low-density structural alternative to conventional titanium alloys and superalloys in respective temperature ranges. Return