High strength hot corrosion and oxidation resistant, directionally solidified nickel base superalloy and articles
OwnerAlan D. Cetelinventor
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Abstract
Corrosion and oxidation resistant, high strength, directionally solidified superalloy alloys and articles are described. The articles have a nominal composition in weight percent of about 12% Cr, 9% Co, 1.9% Mo, 3.8% W, 5% Ta, 3.6% Al, 4.1% Ti, 0.015% B, 0.1% C, up to about 0.02 Zr, balance essentially nickel, and include no intentional additions of hafnium or zirconium, and also have a small amounts of tantalum carbide. The resultant articles have good hot corrosion resistance and superior oxidation resistance and creep properties. The articles are preferably columnar grain, but may also be single crystal.
Claims14
A directionally solidified article comprising a high strength, corrosion and oxidation resistant nickel base superalloy which comprises a matrix and from about 0.4 to 1.5 vol. % of a phase based on tantalum carbide, the alloy consisting essentially of, in weight percent, of:
- 10-13.5% chromium;
- 8-10% cobalt;
- 1.25-2.5% molybdenum;
- 3.25-4.25% tungsten;
- 4.5-6% tantalum;
- 3.25-4.5% aluminum;
- 3-4.75% titanium;
- 0.0025-0.025% boron;
- up to about 0.05% zirconium;
- 0.05-0.15% carbon;
- and having no intentional addition of niobium;
- no intentional addition of hafnium;
- and balance essentially nickel;
- wherein aluminum+titanium is between about 6.5-8%;
- said article having at least comparable hot corrosion resistance (measured at 1600° F.) and at least twice the oxidation resistance (measured at 2000° F.) when compared with a directionally solidified having a nominal composition of 14 Cr, 4.9 Ti, 1.5 Mo, 3.8 W, 2.8 Ta, 3 Al, 9.5 Co, 0.01 B, 0.02 Zr, 0.1 C, and balance Ni.
A high strength, corrosion resistant, nickel base superalloy adapted for use in columnar grain directionally solidified articles, comprising in weight percent of about 12% chromium;
- 9% cobalt;
- 1.9% molybdenum;
- 3.8% tungsten;
- 5% tantalum;
- 3.6% aluminum;
- 4.1% titanium;
- 0.015% boron;
- 0.1% carbon;
- and having no intentional addition (and in any event less than about 0.02) zirconium and no intentional amount of niobium;
- balance essentially nickel and incidental impurities, and wherein aluminum+titanium is between about 6.5-8%;
- and including a matrix containing from about 0.4 to 1.5 vol. % of a phase based on tantalum carbide, the article is characterized by oxidation resistance at 2000° F. of roughly 2.5× and creep rupture life at 1400° F. of roughly 2.4× compared to a similar article having a nominal composition of 14 Cr, 4.9 Ti, 1.5 Mo, 3.8 W, 2.8 Ta, 3 Al, 9.5 Co, 0.01 B, 0.02 Zr, 0.1 C, and balance Ni.
Dependencies are inferred from the claim text.