General Electric Company

Earl W Ross

Kevin S O'Hara

William Scott Walston

Ramgopal Darolia

Tresa M Pollock

Curtiss Mitchell Austin

Wendy Howard Murphy

Warren Tan King

Carl S Wukusick

The present invention provides a nickel base superalloy having an improved combination of stress rupture life and microstructural stability with respect to the formation of TCP phases. A unique feature is the specific combination of the content of elements consisting of Al, Ti and W in a second range defined by their sum in a nickel base superalloy having high contents of rhenium, in excess of 1.3 atomic percent (about 4.0 weight percent) to lower the propensity for TCP phase formation and thus render the alloy more stable at high temperatures. The interaction of Ru with the remaining elements to modify the refractory element phase partitioning provides unique capabilities, causing elements to partition to the gamma phase or the gamma prime phase in a reverse direction than normally experienced in Ni-base superalloys. These Ni-base superalloys are termed Ru-containing Reverse Partitioning Ni-base Superalloys. The composition of these Reverse Partitioning Ni-base superalloys is in the range, in atomic percent, of 1.3-3% Re, 2.0-3.7% Ta, 4.0-18.0% Co, 0-0.2% Hf, 0-0.3% C, 0-0.05% B, 0-0.03% Y, 0-2.0% Mo, 1.5-7.2% Cr, 0-0.3% Cb, 12.0-15.0% Al, 0-1.3% Ti, 1.0-2.5% W, in combination with 0.25-4.0 Ru and the balance Ni and incidental impurities.

Nickel base superalloy and article

A nickel base superalloy capable of being made into a single crystal article is provided with high temperature strength and improved stability by limiting the presence of an undesirable SRZ constituent. Significant to the control of formation of such undesirable constituents is the control of the amount of Re in the alloy in combination with elements such as Al, Cr, Ta, Mo, Co and W. A solution heat treatment is provided for additional control.

Nickel-base superalloy and article with high temperature strength and

There is provided by the present invention nickel-base superalloys for producing single crystal articles having improved tolerance to low angle grain boundaries and an improved balance between cyclic oxidation and hot corrosion resistance. The improved tolerance arises from the discovery that nickel-base superalloys suitable for casting as single crystal articles can be improved by the addition of small, but controlled, amounts of boron and carbon, and optionally hafnium, and is manifested principally by improved grain boundary strength. As one result of this increased grain boundary strength, grain boundary mismatches far greater than the 6.degree. limit for prior art single crystal superalloys can be tolerated in single crystal articles made from the nickel-base superalloys of this invention. This translates, for example, into lower inspection costs and higher casting yields as grain boundaries over a broader range can be accepted by visual inspection techniques without resort to expensive X-ray techniques. These alloys are especially useful when directionally solidified as hot-section components of aircraft gas turbine engines, particularly rotating blades and stationary vanes. The superalloy contains by weight percent, 7-12 Cr, 5-15 Co, 0.5-5 Mo, 3-12 W, 2-6 Ta, 2-5 Ti, 3-5 Al, 0- 2 Cb, 0.1-0.2 Hf, 0.05-0.07 C, 0.002-0.05 B, and nickel.

Nickel-based superalloys for producing single crystal articles having

A nickel base superalloy capable of being made into a single crystal article is provided with high temperature strength and improved stability by limiting the Presence of an undesirable SRZ constituent. Significant to the control of formation of such undesirable constituents is the control of the amount of Re in the alloy in combination with elements such as Al, Cr, Ta, Mo, Co and W. A solution heat treatment is provided for additional control.

One form of an improved cast, hollow, columnar grain nickel base alloy article is provided with outstanding elevated temperature stability as represented by oxidation resistance, an improved combination of longitudinal and transverse stress rupture properties, and a thin wall of less than about 0.035 inch, substantially free of cracks. Described is a heat treatment in combination with an alloy for providing such an article.

Cast columnar grain hollow nickel base alloy articles and alloy and heat

A nickel-based superalloy consisting essentially of, in weight percent, from about 4 to about 5 percent chromium, from about 11 to about 14 percent cobalt, from about 4 to about 8 percent tungsten, from about 6 to about 10 percent tantalum, from about 5 to about 7 percent aluminum, from about 5.5 to about 8 percent rhenium, from about 0 to about 0.50 percent hafnium, from about 0 to about 0.07 percent carbon, from 0 to about 0.01 percent boron, from 0 to about 0.030 percent yttrium, from 0 to about 6 percent ruthenium, from 0 to about 1 percent molybdenum, from 0 to about 1 percent niobium, and the balance essentially nickel. Articles made from the superalloy of the invention are especially useful when cast as single crystal airfoils for use in advanced gas turbine engines.

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Cincinnati, OH, United States of America

Earl W Ross