Abstract: A process is disclosed for forming an improved aluminide coating which includes one or more oxygen active elements. A metallic substrate is coated with an overlay coating, such as an MCrAl coating, including one or more oxygen active elements such as yttrium, hafnium and silicon, by a conventional overlay process such as low pressure plasma spray. A metal, preferably a Series VIII transition metal such as platinum, is applied to the substrate, for example by electroplating. The substrate is then aluminized, for example by chemical vapor deposition, and is preferably heat treated. A ceramic thermal barrier may also be applied. The present invention provides an active element containing aluminide coating having a more consistent composition and having improved durability, either as a standalone coating or as a bond coat for a subsequently-applied thermal barrier coating.

Abstract: Compositional requirements and processing improvements are disclosed which improve the hydrogen embrittlement resistance and the fatigue resistance in air of nickel base single crystal articles. The compositional requirements enlarge the difference between the &ggr;′ solvus temperature and the incipient melting temperature, thus enabling the solution of &ggr;/&ggr;′ eutectic islands without causing incipient melting, while hot isostatic pressing and careful melt practice eliminate porosity and carbides, borides and nitrides, all of which act as crack initiation sites.

Abstract: Improved compositions for fabricating nickel superalloy single crystal articles are described. The compositions are characterized by the substantial absence of carbon, boron, zirconium and vanadium and intentional additions of cobalt. The cobalt additions increase the stability of the compositions and provide enhanced heat treatability. Single crystal articles of these compositions have utility as gas turbine engine components.

Abstract: A superalloy composition and single crystal articles of the composition are disclosed. The broad range, in weight percent, is 3.0-20.0% Co, 5.0-10.0% W, 5.0-7.0% Al, 0.4-2.9% Cr, 4.0-8.0% Ta, 0-1.0% V, 0-8.5% Re, 0-1.5% Ti, 0-3.0% Hf, 0-4.0% Mo, 0-2.0% Nb, 0-10.0% of one or more elements selected from the group consisting of Ru, Rh, Pd, Os, Ir, Pt, 0-1.0 of one or more elements selected from the group consisting of Y, La, Sc, Ce, lanthanides or actinides series of elements, balance essentially Ni. An equation is presented to select the most useful specific compositions from within this range.

Abstract: Single crystal superalloy castings are described which have excellent oxidation resistance. The oxidation resistance is due to the presence of small but effective amounts of magnesium in the casting. Single crystal castings containing magnesium in the range of 5-200 parts per million, by weight, are described.

Abstract: Single crystal superalloy castings are described which have excellent oxidation resistance. The oxidation resistance is due to the presence of small but effective amounts of magnesium in the casting. Single crystal castings containing magnesium in the range of 5-200 parts per million, by weight, are described.

Abstract: Superalloy articles are made more oxidation resistant by a process which includes heat treating the article in the presence of foreign chemical species, at a temperature at which the foreign chemical species reacts with and modifies any oxide film present on the article surface. The heat treatment is best carried out at a temperature above the gamma prime solvus temperature of the article and below the incipient melting temperature of the article. Alternatively, the heat treatment may be carried out within the range defined by the incipient melting temperature of the article and about 150.degree. C. below the incipient melting temperature of the article. At such temperatures the foreign chemical species reacts with and modifies the oxide film on the article surface. Sulfur is then able to diffuse through such modified film, and a more oxidation resistant component is produced.

Abstract: An article exhibiting superior mechical properties and resistance to oxidation corrosion at elevated temperatures as described. The article has particular utility in gas turbine engines and is comprised of a nickel base superalloy consisting essentially of 3-10% Cr, 12.1-16% Co, 1.0-1.9% Mo, 3-10% W, 0-5% Re, 4-7% Al, 0-1.5% Ti, 0-8% Ta, 0.5-3% Hf, 0-2% Cb, 0-1% V, 0.02-0.12% Zr, 0.03-0.2% C, 0.005-0.25% B, 0-0.15% of an oxygen active element such as yttrium, balance essentially nickel. This composition is melted and directionally solidified in columnar grain form to provide useful articles.

Abstract: The anisotropy typically observed in single crystal nickel base superalloys is reduced by intentionally adding certain small amounts of carbon, boron, zirconium or hafnium, either individually or in combination, to the alloy composition.

Abstract: Nickel base superalloys having properties equal to or better than alloys currently used in gas turbine engines are described. Preferably, the alloys of the present invention are cast into single crystals.

Abstract: Single crystal nickel base superalloys, having low chromium and cobalt contents are described. The alloys have a unique combination of aluminum, tantalum, and rhenium, which results in surprisingly good oxidation and corrosion resistance, and a melting point in excess of 2500.degree. F. The properties of the alloys of the present invention make them suitable for use as components in the high temperature section of gas turbine engines.

Abstract: The additions of minor additions of hafnium and silicon and mixtures thereof to nickel base superalloy single crystal articles provide significantly improved oxidation resistance. The oxidation resistance is improved both for the case of uncoated articles and in the case where a protective coating such as for example, a MCrAlY coated is present. For example the addition of 0.1% hafnium is observed to improve the oxidation resistance by a factor of 4 at 2100.degree. F. and a similar addition improved the coating oxidation resistance by a factor of about 2.5 at 2150.degree. F.

Abstract: A superalloy composition and single crystal articles of the composition are described. The broad range is 3-12% Cr, 0-3% Mo, 3-10% W, 0-5% Re, 6-12% Ta, 4-7% Al, 0-15% Co, 0-0.045% C, 0-0.02% B, 0-0.1% Zr, 0-0.8% Hf, 0-2% Nb, 0-1% V, 0-0.7% Ti, 0-10% (Ru+Rh+Pd+Os+Ir+Pt), balance essentially Ni. An equation is presented to select the most useful specific compositions from within this range. An exemplary preferred composition is 5.0% Cr, 10.0% Co, 2.0% Mo, 6.0% W, 3.1% Re, 5.6% Al, 9.0% Ta, 0.1% Hf, balance essentially Ni.

Abstract: Corrosion resistant, high strength, superalloy single crystal articles are described. Starting with a nominal composition of 11.75% Cr, 9% Co, 1.75% Mo, 4.5% W, 2.5% Ta, 2.5% Al, 4% Ti, balance essentially nickel, intentional additions are made of carbon and extra tantalum. From 0.05-0.15% carbon is added along with sufficient tantalum to combine with the carbon to form tantalum carbon. The resultant articles have substantially improved hot corrosion resistance and creep properties.

Abstract: Nickel base superalloys intended for use at low to moderate temperatures are provided with improved corrosion resistance by the addition of from 0.2 to 0.6% manganese. The manganese addition also improves the creep properties of the alloys. The manganese modified alloys are suited for use as elements in gas turbine engines for marine environments.

Abstract: Single crystal superalloy articles of a composition similar to that of IN-939 are given a combined coating and heat treatment cycle. The cycle includes a solution treatment step, a coating application step, a post coating treatment at a temperature above the gamma prime solvus and one or more aging steps. Articles so treated have improved mechanical properties.

Abstract: The microstructural stability of nickel base alloys at high temperatures is nhanced by the addition of cobalt within the range of 10.0 to 14.9 weight percent for reducing the precipitation of the sigma phase in alloys with more than 12 weight percent chromium. The nickel-base alloys having cobalt addition in the range as set forth are characterized by an electron vacancy number within the range of 2.4 to 2.7 inclusive.

Abstract: A specific composition range and process sequence are described for the production of single crystal superalloy articles which have an exceptional combination of high temperature mechanical properties and resistance to oxidation and hot corrosion. The nominal composition is 6% Ta, 9% Cr, 5% Co, 1% Ti, 1% Mo, 7% W, 5.5% Al, 0.15% Hf balance essentially nickel. Material of this composition is cast and solidifed in single crystal form and heat treated to produce an optimum microstructure.

Abstract: A specific composition range and process sequence are described for the production of single crystal superalloy articles which have an exceptional combination of high temperature mechanical properties and resistance to oxidation and hot corrosion. The nominal composition in weight percent is 7.5% Cr, 5.0% Al, 1.0% Ti, 2.0% Mo, 4.0% W, 12.0% Ta, 5% Co, balance nickel. Material of this composition is cast and solidified in single crystal form and heat treated to produce an optimum microstructure.

Abstract: A specific composition range and process sequence are described for the production of single crystal superalloy articles which have an exceptional combination of high temperature mechanical properties and resistance to oxidation and hot corrosion. The nominal composition is 5.2% Cr, 5.4% Al, 1.1% Ti, 2.0% Mo, 4.9% W, 6.4% Ta, 3% Re, 0.4% V, balance nickel. Material of this composition is cast and solidified in single crystal form and heat treated to produce an optimum microstructure.