Oxidation resistant niobium based alloys

Abstract

Oxidation resistant niobium based alloys have a composition to provide a stable ternary phase such as PtYAl or PdYAl, which supplies yttrium and aluminum to the system and forms a protective oxide such as Yttria-Aluminum-Garnet (YAG) scale at elevated temperature. These niobium based alloys further achieve an optimal combination of oxidation resistance and creep strength through a fine dispersion of a coherent second phase. The alloys, withstanding higher combustion temperatures, are useful for extreme-environment propulsion and power applications, including hot sections of gas turbine engines, aerospace turbine blades, and chemical and petroleum plants, where higher turbine efficiency and reduction of operating costs, by-products emissions, and global fuel reserves consumption are desired.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims benefits and priority of provisional application U.S. Ser. No. 60 / 592,924, filed Jul. 30, 2004, entitled, “Oxidation Resistant Niobium Based Alloys”, which is incorporated herewith by reference.CONTRACTUAL ORIGIN OF THE INVENTION [0002] This disclosure was supported, at least in part, by Air Force Office of Scientific Research, Grant No. F49 620-01-1-0529 and may be subject to contract, license and other rights granted to the United States Government.FIELD OF THE INVENTION [0003] In a principal aspect, the present invention relates to oxidation resistant niobium based alloys, and, in particular, niobium based alloys with a protective oxide scale such as Yttrium-Aluminum-Garnet (YAG), enabling a myriad of practical applications including, but not limited to, turbine blades viable at temperatures in the range of 1100 to 1300° C., and structural and internal operating components in hot sections of nuclear reactors. ...

AI Technical Summary

Benefits of technology

[0007] The invention comprises niobium based alloys having improved oxidation resistance at elevated temperatures, such as for example 1100 degrees C. and above. In an illustrative embodiment of the invention, the niobium based alloys include a c

Problems solved by technology

However, with peak use temperature of 1100° C. being greater than 90% of their melting temperatures, nickel based alloys are reaching the point where there is limited room to improve upon the operating efficiency of manufactured components.

However, conventional niobium based refractory alloys lack appropriate oxidation resistance at high temperatures.

However, conventional niobium based alloys form non-protective oxides that exhibit linear growth kinetics, unlike the protective oxide layer in nickel based alloys.

Current commercial niobium silicide alloys suffer from limited ductility.

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