Nickel-based superalloy and component

Abstract

A nickel-based superalloy is provided, comprising: 5.6 wt% to 6.6 wt% aluminum; 6.0 wt% to 9.0 wt% tantalum; 4.0 wt% to 7.0 wt% chromium; 4.0 wt% to 7.0 wt% tungsten; 0.5 wt% to 2.5 wt% molybdenum; 1.5 wt% to 5.5 wt% rhenium; 7.0 wt% to 13.0 wt% cobalt; and 0.1 wt% to 0.7 wt%... The composition comprises: % hafnium; 0.001 wt% to 0.005 wt% carbon; 0.002 wt% to 0.05 wt% boron; up to 0.1 wt% yttrium; the balance being nickel and unavoidable impurities; wherein the above composition exhibits a fracture life exceeding 80 hours at 1093.3 °C and 20 ksi, and oxidation resistance with a surface loss of less than 25.4 μm after a 400-hour Mach I test at 1176.7 °C. Components formed from this nickel-based superalloy are also provided.

Description

[0001] Federal government-funded research

[0002] This invention was developed with government support under contract number N00014-16-C-2002 granted by the Department of Defense. The U.S. government may hold certain rights to this invention. Technical Field

[0003] This disclosure relates to a nickel-based superalloy and components made of such nickel-based superalloy. Background Technology

[0004] Nickel-based single-crystal superalloys are widely used in turbine blades, nozzles, and shields of aero engines. To improve engine performance, aero engine design requires alloys to have increasingly higher temperature resistance, mainly manifested in improved creep strength (creep resistance). Attached Figure Description

[0005] Referring to the accompanying drawings, the specification describes a full and implementable disclosure (including its best mode) for those skilled in the art, wherein:

[0006] Figure 1 It is a perspective view of a component (such as a gas turbine blade) that includes the exemplary nickel-based superalloys discussed herein;

[0007] Figure 2 This is a cross-sectional schematic diagram of an exemplary gas turbine engine according to various embodiments of this subject matter; and

[0008] Figure 3 This is a table showing the chemical composition and test results of exemplary nickel-based superalloys and eight comparative superalloys according to the following embodiments. Detailed Implementation

[0009] Alloys with increased content of solid solution strengthening elements (such as Ta, W, Re, and Mo) also offer improved creep resistance, typically manifested as decreased phase stability, increased density, and lower creep resistance. Second-generation alloys, while possessing relatively stable microstructures, do not exhibit high strength. Third- and fourth-generation alloys exhibit increased strength due to the addition of high levels of refractory metals. For example, these alloys include high levels of tungsten, rhenium, and ruthenium. These refractory metals have much higher densities than nickel-based alloys, thus increasing the overall density of the alloy. For example, fourth-generation alloys may be about 6% heavier than second-generation alloys. The increased weight and cost of these alloys limit their applications to specific uses. Third- and fourth-generation alloys are also limited by microstructural instability, which can affect long-term mechanical properties.

[0010] Subsequent generations of superalloy development focused on improving the creep strength and temperature resistance of the previous generation. For example, the third-generation superalloys showed an approximately 28°C improvement in creep resistance compared to the second-generation superalloys. Fourth and fifth-generation superalloys further enhanced creep strength through high levels of solid solution strengthening elements such as rhenium, tungsten, tantalum, molybdenum, and the addition of ruthenium. As the creep resistance of directionally solidified superalloys improved with each generation, subsequent generations of superalloys compromised on environmental resistance and oxidation resistance.

[0011] Current single-crystal alloys typically contain 0.03 wt% to 0.05 wt% carbon to enhance low-angle boundary strength. However, there is a desire to provide single-crystal superalloy compositions with longer fracture life and improved oxidation resistance.

[0012] Reference will now be made in detail to embodiments of the present disclosure, with more than one embodiment shown in the accompanying drawings. Detailed description uses numerals and letters to denote features in the drawings. In the drawings and description, similar or analogous reference numerals denote similar or analogous parts of the present disclosure.

[0013] As used herein, the term "exemplary" means "as an embodiment, example, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as being more preferred or advantageous than other implementations. Furthermore, unless specifically indicated, all implementations described herein should be considered exemplary.

[0014] The singular forms of “a,” “a kind,” and “the” are used, unless the context clearly specifies otherwise, including the plural.

[0015] The term “at least one” (e.g., “at least one of A, B and C”) in the context means only A, only B, only C, or any combination of A, B and C.

[0016] In this disclosure, chemical elements are discussed using their commonly used chemical abbreviations, such as those commonly found on the periodic table. For example, hydrogen is represented by its commonly used chemical abbreviation H, helium by its commonly used chemical abbreviation He, and so on.

[0017] As used herein, the term "substantially free" should be understood to mean completely free of the said ingredient, or containing trace amounts of the ingredient. "Trace amounts" refers to quantitative levels of chemical components that are virtually undetectable and do not contribute to the functional or aesthetic properties of the subject composition. The term "substantially free" also includes completely free.

[0018] Nickel-based superalloys are generally provided, including components superformed from single-crystal nickel-based superalloys (e.g., for turbine blades). Generally, nickel-based superalloys exhibit improved fracture life and oxidation resistance compared to their base alloys. This improved performance is achieved by reducing the carbon content in the base alloy, which surprisingly leads to improvements in corrosion, oxidation, and creep strength. For example, the carbon content is limited to a maximum of 0.005 wt% carbon. Exemplary embodiments disclosed herein involve extremely reduced carbon content (e.g., 0.001 wt% to 0.005 wt% carbon, such as 0.001 wt% to 0.003 wt% carbon) to improve fracture life and oxidation resistance.

[0019] The exemplary embodiments disclosed herein provide unique alloying methods for obtaining nickel-based superalloys with enhanced oxidation resistance and fracture resistance. In specific embodiments, the composition and / or components formed from the composition exhibit a fracture life exceeding 80 hours at 1093.3°C and oxidation resistance with a surface loss of less than 25.4 μm (i.e., 1 mil) after 400 hours of Mach I testing at 1176.7°C. In some embodiments, the composition and / or components formed from the composition exhibit a fracture life exceeding 100 hours at 1093.3°C (e.g., 100 to 200 hours at 1093.3°C) and oxidation resistance with a surface loss of less than 25.4 μm after 600 hours of Mach I testing at 1176.7°C (e.g., less than 25.4 μm after 600 to 1000 hours of Mach I testing at 1176.7°C).

[0020] The exemplary embodiments disclosed herein may include aluminum to enhance the oxidation resistance of nickel-based superalloys. For example, the nickel-based superalloy may contain 5.6 wt% to 6.6 wt% aluminum.

[0021] The exemplary embodiments disclosed herein may include tantalum to enhance the gamma-prime strength of nickel-based superalloys. For example, the nickel-based superalloy may contain 6.0 wt% to 9.0 wt% tantalum (e.g., 6.25 wt% to 7.5 wt% tantalum).

[0022] The exemplary embodiments disclosed herein may include chromium to improve the heat corrosion resistance of nickel-based superalloys. For example, the nickel-based superalloy may contain 4.0 wt% to 7.0 wt% chromium.

[0023] The exemplary embodiments disclosed herein may include tungsten as a reinforcing agent in nickel-based superalloys. For example, the nickel-based superalloy may contain 4.0 wt% to 7.0 wt% tungsten (e.g., 4.0 wt% to 6.0 wt% tungsten).

[0024] The exemplary embodiments disclosed herein may include molybdenum to enable solid solution strengthening of nickel-based superalloys. For example, the nickel-based superalloy may contain 0.5 wt% to 2.5 wt% molybdenum (e.g., 1 wt% to 2 wt% molybdenum).

[0025] The exemplary embodiments disclosed herein may include rhenium, an effective solid solution strengthening agent classified as the γ phase in nickel-based superalloys. Furthermore, rhenium is also a slow-diffusion element, which limits the coarsening of the γ' phase. For example, the nickel-based superalloy may contain 1.5 wt% to 5.5 wt% rhenium.

[0026] The exemplary embodiments disclosed herein may include cobalt in nickel-based superalloys. For example, a nickel-based superalloy may contain 7.0 wt% to 13.0 wt% cobalt.

[0027] The exemplary embodiments disclosed herein may optionally include hafnium, which can enhance the oxidation resistance and heat corrosion resistance of nickel-based superalloys. When a thermal barrier coating is applied thereto, hafnium can improve the life of the thermal barrier coating. For example, the nickel-based superalloy may contain 0.1 wt% to 0.7 wt% hafnium (e.g., 0.1 wt% to 0.3 wt% hafnium).

[0028] The exemplary embodiments disclosed herein may include boron to provide tolerance to small-angle grain boundaries in nickel-based superalloys. Exemplary embodiments may contain about 0.002 to about 0.05 wt% boron. In one specific embodiment, the boron content may be increased to offset any small-angle grain boundary strength reduction caused by a decrease in carbon concentration.

[0029] By summing the concentrations of these specific elements, nickel-based superalloys exhibit the enhanced oxidation resistance and fracture resistance discussed above (e.g., fracture life exceeding 80 hours at 1093.3 °C, and oxidation resistance with less than 25.4 μm surface loss after 400 hours of Mach I testing at 1176.7 °C).

[0030] In one embodiment, the nickel-based superalloy comprises: 5.6 wt% to 6.6 wt% aluminum; 6.0 wt% to 9.0 wt% tantalum (e.g., 6.25 wt% to 7.5 wt% tantalum); 4.0 wt% to 7.0 wt% chromium; 4.0 wt% to 7.0 wt% tungsten (e.g., 4.0 wt% to 6.0 wt% tungsten); and 0.5 wt% to 2.5 wt% molybdenum (e.g., 1 wt% to 2 wt% molybdenum). 1.5 wt% to 5.5 wt% rhenium; 7.0 wt% to 13.0 wt% cobalt; 0.1 wt% to 0.7 wt% hafnium (e.g., 0.1 wt% to 0.3 wt% hafnium); 0.001 wt% to 0.005 wt% carbon (e.g., 0.001 wt% to 0.003 wt% carbon); 0.002 wt% to 0.05 wt% boron; up to 0.1 wt% yttrium; balance nickel and unavoidable impurities.

[0031] In one specific embodiment, the nickel-based superalloy comprises: 5.6 wt% to 6.6 wt% aluminum (e.g., 6.0 wt% to 6.4 wt% aluminum); 6.0 wt% to 9.0 wt% tantalum (e.g., 6.25 wt% to 7.5 wt% tantalum, such as 6.5 wt% to 7 wt% tantalum); 4.0 wt% to 7.0 wt% chromium (e.g., 6.0 wt% to 7 wt% chromium); 4.0 wt% to 7.0 wt% tungsten (e.g., 4.0 wt% to 6.0 wt% tungsten); and 0.5 wt% to 2.5 wt% molybdenum (e.g., 1 wt% to 1 wt% molybdenum). 2 wt% molybdenum; 1.5 wt% to 5.5 wt% rhenium (e.g., 2.5 wt% to 3.5 wt% rhenium); 7.0 wt% to 13.0 wt% cobalt (e.g., 6.0 wt% to 8.0 wt% cobalt); 0.1 wt% to 0.7 wt% hafnium (e.g., 0.1 wt% to 0.3 wt% hafnium); 0.001 wt% to 0.005 wt% carbon (e.g., 0.001 wt% to 0.003 wt% carbon); 0.002 wt% to 0.05 wt% boron; up to 0.1 wt% yttrium; balance nickel and unavoidable impurities. For example, a nickel-based superalloy may contain: 6.0 wt% to 6.4 wt% aluminum; 6.5 wt% to 7 wt% tantalum; 6.0 wt% to 7 wt% chromium; 4.0 wt% to 6.0 wt% tungsten; 1 wt% to 2 wt% molybdenum; 2.5 wt% to 3.5 wt% rhenium; 6.0 wt% to 8.0 wt% cobalt; 0.1 wt% to 0.3 wt% hafnium; 0.001 wt% to 0.003 wt% carbon; 0.002 wt% to 0.05 wt% boron; 0.001 wt% to 0.1 wt% yttrium; with the balance being nickel and unavoidable impurities. In one specific embodiment, the nickel-based superalloy comprises: 6.0 wt% to 6.4 wt% aluminum; 6.5 wt% to 7 wt% tantalum; 6.0 wt% to 7 wt% chromium; 4.0 wt% to 6.0 wt% tungsten; 1 wt% to 2 wt% molybdenum; 2.5 wt% to 3.5 wt% rhenium; 6.0 wt% to 8.0 wt% cobalt; 0.1 wt% to 0.3 wt% hafnium; 0.001 wt% to 0.003 wt% carbon; 0.002 wt% to 0.05 wt% boron; 0.001 wt% to 0.1 wt% yttrium; with the balance being nickel and unavoidable impurities.

[0032] In one specific embodiment, the nickel-based superalloy comprises: 5.6 wt% to 6.6 wt% aluminum (e.g., 5.6 wt% to 6.0 wt% aluminum); 6.0 wt% to 9.0 wt% tantalum (e.g., 6.25 wt% to 7.5 wt% tantalum, such as 7.0 wt% to 7.5 wt% tantalum); 4.0 wt% to 7.0 wt% chromium (e.g., 4.0 wt% to 5 wt% chromium); 4.0 wt% to 7.0 wt% tungsten (e.g., 4.0 wt% to 6.0 wt% tungsten); 0.5 wt% to 2.5 wt% molybdenum (e.g., 1 wt% to 2 wt% molybdenum); 1.5 wt%... Rhenium (e.g., 5.0 wt% to 5.5 wt%); cobalt (e.g., 12.0 wt% to 13.0 wt%); hafnium (e.g., 0.1 wt% to 0.7 wt%); carbon (e.g., 0.1 wt% to 0.3 wt%); boron (e.g., 0.001 wt% to 0.005 wt%; yttrium (e.g., 0.001 wt% to 0.003 wt%, such as 0.001 wt% to 0.0015 wt%); boron (0.002 wt% to 0.05 wt%); yttrium (up to 0.1 wt%); balance nickel and unavoidable impurities. In one specific embodiment, the nickel-based superalloy may comprise: 5.6 wt% to 6.0 wt% aluminum; 7.0 wt% to 7.5 wt% tantalum; 4.0 wt% to 5 wt% chromium; 4.0 wt% to 6.0 wt% tungsten; 1 wt% to 2 wt% molybdenum; 5.0 wt% to 5.5 wt% rhenium; 12.0 wt% to 13.0 wt% cobalt; 0.1 wt% to 0.3 wt% hafnium; 0.001 wt% to 0.0015 wt% carbon; 0.002 wt% to 0.05 wt% boron; 0.001 wt% to 0.1 wt% yttrium; with the balance being nickel and unavoidable impurities. In one specific embodiment, the nickel-based superalloy comprises: 5.6 wt% to 6.0 wt% aluminum; 7.0 wt% to 7.5 wt% tantalum; 4.0 wt% to 5 wt% chromium; 4.0 wt% to 6.0 wt% tungsten; 1 wt% to 2 wt% molybdenum; 5.0 wt% to 5.5 wt% rhenium; 12.0 wt% to 13.0 wt% cobalt; 0.1 wt% to 0.3 wt% hafnium; 0.001 wt% to 0.0015 wt% carbon; 0.002 wt% to 0.05 wt% boron; 0.001 wt% to 0.1 wt% yttrium; with the balance being nickel and unavoidable impurities.

[0033] In one embodiment, the nickel-based superalloy comprises: 5.6 wt% to 6.6 wt% aluminum (e.g., 6.0 wt% to 6.5 wt% aluminum); 6.0 wt% to 9.0 wt% tantalum (e.g., 6.25 wt% to 7.5 wt% tantalum, e.g., 6.0 wt% to 7.0 wt% tantalum); 4.0 wt% to 7.0 wt% chromium (e.g., 5.5 wt% to 6.5 wt% chromium); 4.0 wt% to 7.0 wt% tungsten (e.g., 5.5 wt% to 7.0 wt% tungsten); 0.5 wt% to 2.5 wt% molybdenum (e.g., 1.5 wt% to 2.5 wt% molybdenum); 1 0.5 wt% to 5.5 wt% rhenium (e.g., 1.5 wt% to 2.0 wt% rhenium); 7.0 wt% to 13.0 wt% cobalt (e.g., 7.0 wt% to 8.0 wt% cobalt); 0.1 wt% to 0.7 wt% hafnium (e.g., 0.5 wt% to 0.7 wt% hafnium); 0.001 wt% to 0.005 wt% carbon (e.g., 0.001 wt% to 0.003 wt% carbon); 0.002 wt% to 0.05 wt% boron (e.g., 0.002 wt% to 0.05 wt% boron); up to 0.1 wt% yttrium; the balance being nickel and unavoidable impurities. In one specific embodiment, the nickel-based superalloy may comprise: 6.0 wt% to 6.5 wt% aluminum; 6.0 wt% to 7.0 wt% tantalum; 5.5 wt% to 6.5 wt% chromium; 5.5 wt% to 7.0 wt% tungsten; 1.5 wt% to 2.5 wt% molybdenum; 1.5 wt% to 2.0 wt% rhenium; 7.0 wt% to 8.0 wt% cobalt; 0.5 wt% to 0.7 wt% hafnium; 0.001 wt% to 0.003 wt% carbon; 0.002 wt% to 0.05 wt% boron; up to 0.1 wt% yttrium; with the balance being nickel and unavoidable impurities. In one specific embodiment, the nickel-based superalloy comprises: 6.0 wt% to 6.5 wt% aluminum; 6.0 wt% to 7.0 wt% tantalum; 5.5 wt% to 6.5 wt% chromium; 5.5 wt% to 7.0 wt% tungsten; 1.5 wt% to 2.5 wt% molybdenum; 1.5 wt% to 2.0 wt% rhenium; 7.0 wt% to 8.0 wt% cobalt; 0.5 wt% to 0.7 wt% hafnium; 0.001 wt% to 0.003 wt% carbon; 0.002 wt% to 0.05 wt% boron; up to 0.1 wt% yttrium; with the balance being nickel and unavoidable impurities.

[0034] As previously mentioned, nickel-based superalloys with extremely low carbon content are particularly suitable for use as components in high-temperature environments, such as components present in gas turbine engines, including combustor components, turbine blades, shields, nozzles, heat shields, and vanes. In one specific embodiment, an exemplary nickel-based superalloy can be used to form components located within the hot air passages of a gas turbine.

[0035] The exemplary embodiments disclosed herein include components such as blades, nozzles, shrouds, splash guards, and burners of a gas turbine engine, wherein such components having the above-described compositions substantially comprise single crystals. The use of the exemplary alloy compositions discussed herein is not limited to gas turbine blades; they can be used in other components 100, particularly components 100 within a turbine, such as gas turbine nozzles, blades, shrouds, or other components of a gas turbine engine. The term “turbine” or “turbomachinery” refers to a machine comprising one or more compressors, a heat-generating section (e.g., a combustion section), and one or more turbines that collectively produce torque output. The term “gas turbine engine” refers to an engine that uses a turbine as its power source, either entirely or partially. Example gas turbine engines include turbofan engines, turboprop engines, turbojet engines, turboshaft engines, and hybrid electric versions of one or more of these engines.

[0036] Refer to the attached diagram. Figure 1 A component 100 of a gas turbine engine is depicted, illustrated as a gas turbine blade. Component 100 includes an airfoil 120, a laterally extending platform 160, and a structure for connecting component 100 to a turbine disk (discussed below). Figure 2 The dovetail-shaped connector 140. In some components, multiple cooling channels extend through the interior of the airfoil 120 and terminate at an opening 180 on the surface of the airfoil 120.

[0037] In one exemplary embodiment, component 100 is substantially single-crystal. That is, at least 80 vol% (vol%), for example, 80 vol% to 100 vol% (e.g., 95 vol% to 100 vol%) of component 100 is a single crystal with a single crystal orientation. There may be other crystal orientations with small volume fractions, as well as regions separated by small-angle grain boundaries. The single-crystal structure is prepared by the directional solidification of the alloy composition, typically by seed crystals or other structures that induce single-crystal and single-crystal orientation growth.

[0038] Figure 2 This is a schematic cross-sectional view of a gas turbine engine according to an exemplary embodiment of the present disclosure. More specifically, for Figure 2 In this implementation, the gas turbine engine is a high-bypass turbofan engine 10, referred to herein as "turbofan engine 10". For example... Figure 2As shown, the turbofan engine 10 defines an axial direction A (extending parallel to the longitudinal axis 12 for reference) and a radial direction R. Generally, the turbofan engine 10 includes a fan section 14 and a core turbine engine 16 disposed downstream of the fan section 14. Although described below with reference to the turbofan engine 10, this disclosure is generally applicable to turbomachinery, including turbojet, turboprop, and turboshaft gas turbine engines, including industrial and marine gas turbine engines and auxiliary power units. It is also applicable to other high-temperature applications where water vapor is present in the gas phase, such as water vapor produced by the combustion of hydrocarbon fuels.

[0039] The depicted exemplary core turbine engine 16 generally includes a generally tubular housing 18 defining an annular inlet 20. The housing 18, in a series flow relationship, includes: a compressor section comprising a boost or low-pressure (LP) compressor 22 and a high-pressure (HP) compressor 32; a combustion section 26; a turbine section comprising a high-pressure (HP) turbine 28 and a low-pressure (LP) turbine 30; and an exhaust nozzle section 32. A high-pressure (HP) shaft or spool 34 drives the HP turbine 28 to the HP compressor 24. A low-pressure (LP) shaft or spool 36 drives the LP turbine 30 to the LP compressor 22.

[0040] In the described embodiment, fan section 14 includes a variable-pitch fan 38 having a plurality of fan blades 40 spaced apart from disk 42. As shown, the fan blades 40 generally extend outward from disk 42 along a radial direction R. Since the fan blades 40 are operatively connected to suitable actuating components 44, each fan blade 40 rotates relative to disk 42 about a tilt axis P, and the actuating components 44 are configured to uniformly and collectively change the pitch of the fan blades 40. The fan blades 40, disk 42, and actuating components 44 rotate together about a longitudinal axis 12 via an LP spool 36 passing through an optional power gearbox 46. The power gearbox 46 includes a plurality of gears for progressively reducing the rotational speed of the LP spool 36 to a more efficient fan speed.

[0041] Continue to refer to Figure 2 In an exemplary embodiment, disk 42 is covered by a rotatable forward nacelle 48 having an aerodynamic profile to facilitate airflow through multiple fan blades 40. Furthermore, the exemplary fan portion 14 includes an annular fan housing or outer nacelle 50 circumferentially surrounding at least a portion of the fan 38 and / or the core turbine engine 16. It should be understood that the nacelle 50 can be configured to be supported relative to the core turbine engine 16 by a plurality of circumferentially spaced outlet guide vanes 52. Additionally, a downstream portion 54 of the nacelle 50 may extend externally over the core turbine engine 16 to define a bypass airflow passage 56 therebetween.

[0042] During operation of the turbofan engine 10, a volume of air 58 enters the turbofan engine 10 through the relevant inlet 60 of the nacelle 50 and / or the fan section 14. As the volume of air 58 passes through the fan blades 40, a first portion of the air 58, as indicated by arrow 62, is directed or guided into the bypass airflow passage 56, and a second portion of the air 58, as indicated by arrow 64, is directed or guided into the LP compressor 22. The ratio between the first portion of air 62 and the second portion of air 64 is commonly referred to as the bypass ratio. The pressure of the second portion of air 64 then increases as it is guided through the high-pressure (HP) compressor 24 and into the combustion section 26, where it mixes with fuel and is burned to provide combustion gases 66.

[0043] Combustion gas 66 is guided through HP turbine 28, where it passes through a series of stages: HP turbine stator blades 68 connected to housing 18 and HP turbine rotor blades 70 connected to HP shaft or spool 34. Part of the thermal and / or kinetic energy from the combustion gas 66 is extracted, causing the HP shaft or spool 34 to rotate, thereby supporting the operation of HP compressor 24. Then, combustion gas 66 is guided through LP turbine 30, where it passes through a series of stages: LP turbine stator blades 72 connected to housing 18 and LP turbine rotor blades 74 connected to LP shaft or spool 36. A second portion of the thermal and kinetic energy from the combustion gas 66 is extracted, causing the LP shaft or spool 36 to rotate, thereby supporting the operation of LP compressor 22 and / or fan 38.

[0044] Combustion gas 66 is then directed through the injection exhaust nozzle section 32 of the core turbine engine 16 to provide propulsion. Simultaneously, the pressure of the first portion of air 62 increases significantly as it is directed through the bypass airflow passage 56 before exiting from the fan nozzle exhaust section 76 of the turbofan engine 10, also providing propulsion. The HP turbine 28, LP turbine 30, and injection exhaust nozzle section 32 at least partially define the hot gas passage 78 for directing combustion gas 66 through the core turbine engine 16.

[0045] Example

[0046] An exemplary nickel-based superalloy was prepared and compared with eight comparative nickel-based superalloys. Figure 3 The chemical compositions of exemplary alloys and eight comparative nickel-based superalloys are shown, along with the resulting fracture life (in hours) and Mach I oxidation (in hours) data. Figure 3 The test results clearly show that the reduction in carbon content in the exemplary nickel-based superalloy leads to an increase in fracture life and Mach I oxidation.

[0047] Fracture life was measured according to ASTM E139-11. Oxidation resistance was determined by a Mach I test run at a cycle rate of 20 cycles per hour (30 seconds of heating, 90 seconds of holding, and 60 seconds of cooling per cycle), in which the test probe was exposed to combustion gases produced by the combustion of type A injector fuel with an air / fuel mixture ratio of approximately 30, burning at near Mach I speeds on a rotating disc. Temperature was monitored using a pyrometer. Surface oxidation loss was measured using a Keyence microscope. The test probe, with a diameter of 6.2 mm and a length of 90 mm, was machined from a cast rod of the target alloy.

[0048] Further aspects are provided by the subject matter of the following clauses:

[0049] 1. A nickel-based superalloy comprising: 5.6 wt% to 6.6 wt% aluminum; 6.0 wt% to 9.0 wt% tantalum; 4.0 wt% to 7.0 wt% chromium; 4.0 wt% to 7.0 wt% tungsten; 0.5 wt% to 2.5 wt% molybdenum; 1.5 wt% to 5.5 wt% rhenium; 7.0 wt% to 13.0 wt% cobalt; 0.1 wt% to 0.7 wt% hafnium; 0.001 wt% to 0.005 wt% carbon; 0.002 wt% to 0.05 wt% boron; up to 0.1 wt% yttrium; the balance being nickel and unavoidable impurities; wherein the above composition has a fracture life of more than 80 hours at 1093.3 °C and 20 ksi, and oxidation resistance with a surface loss of less than 25.4 μm after 400 hours of Mach I testing at 1176.7 °C.

[0050] 2. Any of the preceding clauses of the nickel-based superalloy, wherein the nickel-based superalloy contains 0.001 wt% to 0.003 wt% carbon.

[0051] 3. Any of the preceding clauses of the nickel-based superalloy, wherein the nickel-based superalloy comprises 6.25 wt% to 7.5 wt% tantalum.

[0052] 4. Any of the preceding clauses of the nickel-based superalloy, wherein the nickel-based superalloy contains 4.0 wt% to 6.0 wt% tungsten.

[0053] 5. Any of the preceding clauses of the nickel-based superalloy, wherein the nickel-based superalloy contains 1 wt% to 2 wt% molybdenum.

[0054] 6. The nickel-based superalloy of any of the foregoing clauses, wherein the nickel-based superalloy contains 0.1 wt% to 0.3 wt% hafnium.

[0055] 7. The nickel-based superalloy of any of the foregoing clauses, wherein the nickel-based superalloy comprises 6.0 wt% to 6.4 wt% aluminum, 6.5 wt% to 7 wt% tantalum, 6.0 wt% to 7 wt% chromium, 2.5 wt% to 3.5 wt% rhenium, and 6.0 wt% to 8.0 wt% cobalt.

[0056] 8. Any of the preceding clauses of the nickel-based superalloy, wherein the nickel-based superalloy comprises: 6.0 wt% to 6.4 wt% aluminum; 6.5 wt% to 7 wt% tantalum; 6.0 wt% to 7 wt% chromium; 5.0 wt% to 6.0 wt% tungsten; 1 wt% to 2 wt% molybdenum; 2.5 wt% to 3.5 wt% rhenium; 6.0 wt% to 8.0 wt% cobalt; 0.1 wt% to 0.3 wt% hafnium; 0.001 wt% to 0.003 wt% carbon; 0.002 wt% to 0.05 wt% boron; 0.001 wt% to 0.1 wt% yttrium; the balance being nickel and unavoidable impurities.

[0057] 9. Any of the preceding clauses of the nickel-based superalloy, wherein the nickel-based superalloy comprises 5.6 wt% to 6.0 wt% aluminum.

[0058] 10. The nickel-based superalloy of any of the foregoing clauses, wherein the nickel-based superalloy comprises 7.0 wt% to 7.5 wt% tantalum.

[0059] 11. The nickel-based superalloy of any of the foregoing clauses, wherein the nickel-based superalloy contains 4.0 wt% to 5 wt% chromium.

[0060] 12. The nickel-based superalloy of any of the foregoing clauses, wherein the nickel-based superalloy contains 5.0 wt% to 5.5 wt% rhenium.

[0061] 13. The nickel-based superalloy of any of the foregoing clauses, wherein the nickel-based superalloy comprises 12.0 wt% to 13.0 wt% cobalt.

[0062] 14. The nickel-based superalloy of any of the foregoing clauses, wherein the nickel-based superalloy contains 0.001 wt% to 0.0015 wt% carbon.

[0063] 15. Any nickel-based superalloy of the foregoing clauses, wherein the nickel-based superalloy comprises: 5.6 wt% to 6.0 wt% aluminum; 7.0 wt% to 7.5 wt% tantalum; 4.0 wt% to 5 wt% chromium; 4.0 wt% to 6.0 wt% tungsten; 1 wt% to 2 wt% molybdenum; 5.0 wt% to 5.5 wt% rhenium; 12.0 wt% to 13.0 wt% cobalt; 0.1 wt% to 0.3 wt% hafnium; 0.001 wt% to 0.0015 wt% carbon; 0.002 wt% to 0.05 wt% boron; 0.001 wt% to 0.1 wt% yttrium; the balance being nickel and unavoidable impurities.

[0064] 16. The nickel-based superalloy of any of the foregoing clauses, wherein the nickel-based superalloy comprises: 6.0 wt% to 6.5 wt% aluminum; 6.0 wt% to 7.0 wt% tantalum; 5.5 wt% to 6.5 wt% chromium; 5.5 wt% to 7.0 wt% tungsten; 1.5 wt% to 2.5 wt% molybdenum; 1.5 wt% to 2.0 wt% rhenium; 7.0 wt% to 8.0 wt% cobalt; 0.5 wt% to 0.7 wt% hafnium; 0.001 wt% to 0.003 wt% carbon; 0.002 wt% to 0.05 wt% boron; at most 0.1 wt% yttrium; the balance being nickel and unavoidable impurities.

[0065] 17. Components of nickel-based superalloys that include any of the foregoing clauses.

[0066] 18. Any component of the foregoing clauses, wherein the component comprises a single crystal of the nickel-based superalloy.

[0067] 19. Any component of the foregoing clauses, wherein the component comprises 80 vol% to 100 vol% of a single crystal of the nickel-based superalloy.

[0068] 20. Any component of the foregoing clauses, wherein the component is a gas turbine blade.

[0069] This written specification uses examples to disclose this disclosure, including the best mode, and to enable any person skilled in the art to practice this disclosure, including making and using any apparatus or system and performing any incorporated methods. The patentable scope of this disclosure is defined by the claims and may include other embodiments as would be expected by a person skilled in the art. Such other embodiments are intended to fall within the scope of the claims if they contain structural elements that are not different from the literal language of the claims, or if they contain equivalent structural elements that are not substantially different from the literal language of the claims.

Claims

1. A nickel-based superalloy comprising: 5.6 wt% to 6.6 wt% aluminum; 6.0 wt% to 9.0 wt% tantalum; Chromium content greater than 4.0 wt% to 7.0 wt%; 4.0 wt% to 7.0 wt% tungsten; 0.5 wt% to 2.5 wt% molybdenum; Rhenium ranging from 1.5 wt% to 5.5 wt%; 7.0 wt% to 13.0 wt% cobalt; 0.1 wt% to 0.7 wt% of hafnium; 0.001 wt% to 0.003 wt% carbon; Boron from 0.002 wt% to 0.05 wt%; At most 0.1 wt% yttrium; and The balance consists of nickel and unavoidable impurities; in, The nickel-based superalloy exhibits a fracture life exceeding 80 hours at 1093.3 °C and 20 ksi, and oxidation resistance with a surface loss of less than 25.4 µm after a 400-hour Mach I test at 1176.7 °C.

2. The nickel-based superalloy as described in claim 1, wherein, The nickel-based superalloy contains 6.25 wt% to 7.5 wt% tantalum.

3. The nickel-based superalloy as described in claim 1, wherein, The nickel-based superalloy contains 4.0 wt% to 6.0 wt% tungsten.

4. The nickel-based superalloy as described in claim 1, wherein, The nickel-based superalloy contains 1 wt% to 2 wt% molybdenum.

5. The nickel-based superalloy as described in claim 1, wherein, The nickel-based superalloy contains 0.1 wt% to 0.3 wt% hafnium.

6. The nickel-based superalloy as described in claim 1, wherein, The nickel-based superalloy comprises 6.0 wt% to 6.4 wt% aluminum, 6.5 wt% to 7 wt% tantalum, 6.0 wt% to 7 wt% chromium, 2.5 wt% to 3.5 wt% rhenium, and 7.0 wt% to 8.0 wt% cobalt.

7. The nickel-based superalloy as described in claim 1, wherein, The nickel-based superalloy is composed of the following: Aluminum from 6.0 wt% to 6.4 wt%; 6.5 wt% to 7 wt% tantalum; 6.0 wt% to 7 wt% chromium; 5.0 wt% to 6.0 wt% tungsten; 1 wt% to 2 wt% molybdenum; 2.5 wt% to 3.5 wt% rhenium; 7.0 wt% to 8.0 wt% cobalt; 0.1 wt% to 0.3 wt% of hafnium; 0.001 wt% to 0.003 wt% carbon; Boron from 0.002 wt% to 0.05 wt%; 0.001 wt% to 0.1 wt% of yttrium; and The balance is nickel and unavoidable impurities.

8. The nickel-based superalloy as described in claim 1, wherein, The nickel-based superalloy contains 5.6 wt% to 6.0 wt% aluminum.

9. The nickel-based superalloy as described in claim 1, wherein, The nickel-based superalloy contains 7.0 wt% to 7.5 wt% tantalum.

10. The nickel-based superalloy as described in claim 1, wherein, The nickel-based superalloy contains more than 4.0 wt% to 5 wt% chromium.

11. The nickel-based superalloy as described in claim 1, wherein, The nickel-based superalloy contains 5.0 wt% to 5.5 wt% rhenium.

12. The nickel-based superalloy as described in claim 1, wherein, The nickel-based superalloy contains 12.0 wt% to 13.0 wt% cobalt.

13. The nickel-based superalloy as described in claim 1, wherein, The nickel-based superalloy contains 0.001 wt% to 0.0015 wt% carbon.

14. The nickel-based superalloy as described in claim 1, wherein, The nickel-based superalloy is composed of the following: 5.6 wt% to 6.0 wt% aluminum; 7.0 wt% to 7.5 wt% tantalum; Chromium content greater than 4.0 wt% to 5 wt%; 4.0 wt% to 6.0 wt% tungsten; 1 wt% to 2 wt% molybdenum; 5.0 wt% to 5.5 wt% rhenium; 12.0 wt% to 13.0 wt% cobalt; 0.1 wt% to 0.3 wt% of hafnium; 0.001 wt% to 0.0015 wt% carbon; Boron from 0.002 wt% to 0.05 wt%; 0.001 wt% to 0.1 wt% of yttrium; and The balance is nickel and unavoidable impurities.

15. The nickel-based superalloy as described in claim 1, wherein, The nickel-based superalloy is composed of the following: Aluminum from 6.0 wt% to 6.5 wt%; 6.0 wt% to 7.0 wt% tantalum; 5.5 wt% to 6.5 wt% chromium; 5.5 wt% to 7.0 wt% tungsten; 1.5 wt% to 2.5 wt% molybdenum; Rhenium ranging from 1.5 wt% to 2.0 wt%; 7.0 wt% to 8.0 wt% cobalt; 0.5 wt% to 0.7 wt% of hafnium; 0.001 wt% to 0.003 wt% carbon; Boron from 0.002 wt% to 0.05 wt%; At most 0.1 wt% yttrium; and The balance is nickel and unavoidable impurities.

16. A component comprising the nickel-based superalloy of claim 1.

17. The component as claimed in claim 16, wherein, The component comprises a single crystal of the nickel-based superalloy.

18. The component as claimed in claim 16, wherein, The component comprises 80% to 100% by volume of single crystals of the nickel-based superalloy.

19. The component as claimed in claim 16, wherein, The component is a gas turbine blade.

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