Cost-Effective Powder Metallurgy TiAl-Based Components For Aerospace Use

Gamma titanium aluminide (TiAl) alloys with their low density (~3.9g/cm3), good elevated temperature strength, stiffness, creep resistance and acceptable burn and oxidation resistance have excellent potential for use in high temperature aerospace applications at temperatures between 500oC to 1000oC instead of the currently used high density (~8.9g/cm3) Ni-based superalloys. However, its poor intermediate and room temperature ductility cause conventional manufacturing operations such as rolling, forging or drawing to be difficult for titanium aluminides, thus leading to very high cost of TiAl components (currently up to $10,000 per 30? by 12? by 0.04? sheet from an offshore source, Plansee in Austria). In the proposed program cost-effective flat products (sheet/foil) and NNS ?chunky? components of monolithic TiAl and composites concepts (TiAl/Ti high-temp alloy/TiAl, TiAl/Ti3Al/TiAl, and TiAl/ceramic concepts) will be fabricated by a patented loose sintering approach. This low cost approach, which allows flexibility in gauge product, a hot pressing approach, microstructure and mechanical properties of the products as well as formability and joining/diffusion bonding capabilities will be evaluated with the goal of achieving the requirements for structural use. These components can be used in next generation launch vehicle airframe (experiencing extensive aerodynamic heating) and engine applications.