The objective of this proposal is to develop new additive manufacturing process and post treatment procedure for light-weight γ-TiAl. The new procedure will address the unique fine microstructure inherent with additively manufactured component. It will be customized to achieve desired microstructure specific to different application and property requirement. γ-TiAl has attractive properties for structural applications in hypersonic vehicles. Instead of using the procedures set up for traditional manufacturing methods, this new procedure will increase performance while decrease weight and improve fuel efficiency. To meet the challenges in fabricating AM γ-TiAl components, this project will develop new technology based on PI’s two decades’ experience on γ-TiAl and additive manufacturing. ICME approach with thermodynamics model will also be used to guide process optimization. First, additive manufacturing processing parameters will be refined and optimized. Then the additively manufactured coupons will be HIPed and heat treated under guidance of ICME. Microstructure and mechanical properties of as built and post treated AM γ-TiAl coupons will be characterized. Developed new procedure will be used to fabricate complex components. Two application are identified in this proposal: inlet diverter flap in NASA’s turbine based combined cycle (TBCC) propulsion systems and low pressure turbine blade in gas turbine engine. Microstructure and mechanical properties of fabricated components will be characterized to validate the success of new procedure. This project will pave a solid foundation for future standardization and certification of application of additively manufactured γ-TiAl in hypersonic vehicle and other applications. The methodology developed from this project will also provide guidance in processing development for other additive manufacturing application.
NASA focuses on technologies for hypersonic vehicles, including combined cycle, air-breathing propulsion systems. Light weight AM γ-TiAl will find application in the following areas immediately: LPT blades for low pressure turbines, compressor rotor, low pressure turbine rotors, stators and vent, and static nozzle structure as we have done for HSCT. With the capability of AM to increase manufacturability, this technology will expand into new areas due to design freedom.
Light weight AM γ-TiAl technology will find the following high temperature structural application with complex geometry requirement or low batch production: turbo chargers for automotive application, small gas turbine engines for military application, compressor rotor and blade in power plants.