Development of Niobium-Based Alloys for Turbine Applications

Current Ni-based alloys used in turbine blade applications are operating at 1100°C, which is approximately 90% of their melting temperatures. Refractory alloys, such as niobium (Nb) alloys, can withstand higher temperatures. Oak Ridge National Laboratory (ORNL) will use computational modeling tools and advanced characterization to develop two classes of Nb alloys for use in a tri-layered turbine system consisting of a core high strength Nb-alloy layer, an intermediate layer consisting of a more oxidation resistant Nb alloy compatible with a core layer, and an external thermal barrier/coating such as a commercially available silicide coating designed to provide oxidation resistance. The alloys will be able to continuously operate at 1300°C with coatings. This capability will enable gas turbine inlets of 1800°C or higher.