JPH0569891B2 - - Google Patents

Description

[Detailed description of the invention]

The United States Government has rights in this invention pursuant to Contract No. F33615-77-C-5200 awarded by the United States Air Force. DISCLOSURE OF RELATED APPLICATIONS The invention disclosed and claimed herein is disclosed in U.S. Patent Application No. 565,803, filed on the same date as this application.
related to the invention disclosed and claimed in No. BACKGROUND OF THE INVENTION The present invention relates generally to nickel-based superalloys useful for manufacturing high-temperature area components of aircraft gas turbine engines, such as vanes and rotating blades, and in particular from advanced nickel-based superalloys and nickel-based eutectic superalloys. The present invention relates to a compliant coating that is particularly useful for improving the environmental resistance of high heat area components such as those described above. Modern nickel-based superalloys, such as monocarbide-reinforced nickel-based eutectic superalloys of the type described in U.S. Pat. No. 4,292,076 to Giglioffi, Jr. et al. It is designed for use in the form of vanes and rotating blades in gas turbine engines.
The superalloy of U.S. Pat. No. 4,292,076 undergoes directional solidification (DS) under strict conditions.
planar front solidification (PFS)
When achieving front solidification, strong fibers of reinforcing metal carbide (MC) become embedded in the γ/γ′ nickel-based superalloy matrix into a eutectic composite microstructure. Because a highly aligned microscopic structure is formed during planar front solidification, U.S. Pat.
The superalloy of No. 4292076 exhibits potential structural stability and property retention over a wider range of solidification temperatures than other alloys. Eutectic superalloys are considered the next generation blade alloys beyond directionally solidified and single crystal superalloys. However, in order to take full advantage of the thermal advantages of these superalloys, coatings are needed that provide environmental protection at the intended high service temperatures. Stringent requirements are placed on coatings and coating/substrate composites. For example, the coating must be intimately bonded, or metallurgically bonded, to the substrate, ideally based on the mechanical properties of the substrate (e.g. ductility, stress fracture strength, thermal fatigue resistance) and the chemical properties of the substrate (e.g. oxidation resistance). (corrosion resistance and high-temperature corrosion resistance) must not deteriorate. Examples of adverse effects on eutectic superalloys resulting from incompatible coatings include fiber erosion near the coating/substrate interface due to outdiffusion of carbon from the fibers into the coating, and interaction between the coating and the substrate. The formation of brittle precipitates within the substrate due to diffusion is mentioned. Although a number of coatings and barrier/coating systems have been proposed and tried, conventional techniques have generally been based on properties that are truly compatible with the substrate, i.e., provide improved protection from the environment and provide good metallurgical bonding with the substrate. It has not been possible to define a coating or barrier/coating system that forms and does not degrade the mechanical and chemical properties of the substrate, especially when the substrate is made of an alloy of the type described in U.S. Pat. No. 4,292,076. That's true. Accordingly, the latest generation of superalloys, especially superalloys designed for use as vanes and rotating blades in aircraft gas turbine engines, such as the directionally solidified monocarbide reinforced nickel-based superalloys of the type described in U.S. Pat. No. 4,292,076. There is a need for environmentally protective coatings that are truly compatible with eutectic superalloys. SUMMARY OF THE INVENTION In accordance with the present invention, a nickel-based superalloy is provided that is mechanically and chemically compatible with advanced nickel-based superalloys and nickel-based eutectic superalloys and has excellent resistance to high temperature oxidation. be done. The alloys of the present invention therefore provide environmental protection for the external surfaces of high-temperature stage components of aircraft gas turbine engines, such as rotating blades and stationary vanes, formed from advanced nickel-based superalloys and nickel-based eutectic superalloys. Particularly useful as a coating. Broadly speaking, the superalloys of the present invention essentially contain, by weight, 1 to 10% cobalt, 6 to 12% chromium, 5%
~8% aluminum, 1-10% tantalum, 1
~10% tungsten, 0-3% rhenium, 0
~2% molybdenum, 0.1-2% hafnium,
Consisting of 0.005-0.1% boron, 0.005-0.25% carbon, balance nickel and incidental impurities. Although it is contemplated that the new superalloys described above will often be applied as environmentally protective coatings to form at least a portion of the exterior surfaces of gas turbine engine components and articles, the new alloys of the present invention However, it has also been found useful as a fairly thick weld metal deposit formed on selected areas of a substrate, such as an aircraft gas turbine engine component, for repair purposes, or as the tip of a rotating blade. Examples of such applications include an article formed from a nickel-based superalloy or a nickel-based eutectic superalloy, such as an airfoil in a gas turbine engine, as the substrate and continuous with, ie, bonded to and an integral part of, the substrate. Composite manufactured articles are contemplated having one or more thickened welded metal regions forming a portion, where the one or more regions constitute at least a portion of the outer surface of the composite article; It is of the new superalloy composition mentioned above. DESCRIPTION OF THE PREFERRED EMBODIMENTS As explained in the Summary section above, the present invention is mechanically and chemically compatible with advanced nickel-based superalloys and nickel-based eutectic superalloys, and has excellent resistance to high temperature oxidation. The present invention relates to a nickel-based superalloy having properties. The superalloy of the present invention consists essentially of cobalt, chromium, aluminum, tantalum, tungsten, rhenium, molybdenum, hafnium, boron and carbon in the proportions (weight percent) set forth in the table below, with the balance being nickel and It is an incidental impurity.

[Table] The reason for adding each alloying element in the above alloy composition and the reason for limiting the amount added are as follows. Cobalt is required to provide a stable microstructure and also serves to prevent the formation of deleterious topologically close-packed phases (TCP phases). Less than the minimum amount will not provide the required stability, and too much above the maximum amount will prevent the use of other alloying elements by removing room for their use. Chromium is required for high temperature corrosion resistance and also serves to increase the activity of aluminum and aid in the formation of thin aluminum oxide films. If less than the minimum amount is used, high temperature corrosion resistance will not be sufficient. If present in excess of the maximum amount, a harmful TCP phase will be formed at the interface between the coating and the substrate when used as a coating. Aluminum is required to form a protective oxide layer. The minimum amount is the minimum amount necessary to obtain a homogeneous coating. If used in excess of the maximum amount, the melting point of the alloy will decrease. Tantalum is required to strengthen the γ' or reinforcing phase. If it is too small and falls below the minimum amount, a sufficient reinforcing phase will not be provided, and if it is too large and exceeds the maximum amount, the melting start point will be lowered and a TCP phase will be formed. Tungsten is required as a solid solution toughener. If the amount is less than the minimum amount, it will not provide the required reinforcement, and if it is too much and exceeds the maximum amount, it will cause the formation of TCP phase. Rhenium is required as a solid solution toughener.
If the amount is less than the minimum amount, it will not provide the required reinforcement, and if it is too much and exceeds the maximum amount, it will cause the formation of TCP phase. Molybdenum is required as a solid solution toughener. If the amount is less than the minimum amount, it will not provide the required reinforcement, and if it is too much and exceeds the maximum amount, it will cause the formation of TCP phase. Hafnium improves the adhesion of the oxide layer. Below the minimum amount, there is no increase in adhesion. If the amount is too large and exceeds the maximum amount, the melting start point will be lowered. Boron acts as a grain boundary strengthener. Less than the minimum amount provides no additional reinforcement, while too much and above the maximum amount lowers the melting point. Carbon acts as a grain boundary strengthener. Less than the minimum amount provides no additional reinforcement, while too much and above the maximum amount lowers the melting point. The absence of titanium, slightly more aluminum than normal, and the additional presence of hafnium in combination with carbon and other refractory elements present in the right balance provide a protective layer when exposed to air. Helps form and maintain alumina scale, which increases oxidation resistance. The alloys of the present invention operate in solid and hollow fluid-cooled gas turbine engine parts, such as rotating blades and It is particularly useful as an environmentally protective coating for the outer surface of stationary vanes, about 0.002 to 0.1 inch thick. Although it is contemplated that the new alloys described herein may be applied as environmentally protective coatings to form at least a portion of the exterior surfaces of gas turbine engine components and articles, the It has been found that the alloy is also useful as one or more substantial deposits of weld metal applied to selected areas of such article or part-like substrates. Whether the new alloy is applied as a coating or as a fairly thick build-up of deposited metal, plasma spray techniques are preferably used to deposit the alloy of the present invention. Low pressure plasma spraying (LPPD) is described in U.S. Pat. No. 3,839,618 to Muehlberger.
A technique called ``deposition'' is also suitable. The alloys of the present invention produce very dense coatings or sprayed layers after plasma spraying, and in particular by the LPPD method described above, with as-sprayed densities of over 95% readily available. Because the difference in evaporation rate (or vapor pressure) between high vapor pressure elements such as chromium, manganese or aluminum and low vapor pressure elements such as tantalum or tungsten is large, other methods such as physical vacuum evaporation It is difficult, if not impossible, to coat and control the composition of the new alloys of this invention. However, it is understood that it is possible to form coatings by methods such as physical vapor deposition and ion plating without any process improvements or modifications to the methods, and therefore it is also possible to use these methods. being considered. Other techniques such as sputtering and slurry sintering can also be considered. To specifically illustrate the present invention, a series of coatings hereinafter referred to as "6M" or 6M-type coatings for presentation purposes are:
The alloy of the present invention, i.e. essentially 4% Co, 8.5% Cr, 6% in nominal weight percentages within normal melting tolerances.
Al, 5%Ta, 4.5%W, 1.5%Re, 1.5%Mo, 0.9
% Hf, 0.01% B and 0.09% C, balance nickel and incidental impurities, were prepared for environmental testing purposes by low pressure plasma spraying onto flat and pin substrates. . Nickel-based superalloys consistent with U.S. Pat. No. 4,292,076, i.e., essentially on a weight basis, B in excess of the amount of impurities up to 0.02%, Re from 0 to 9%,
<0.8% Ti, 0-20% Cr, 0-10% Al, 3
~15% Ta, 0.1-1% C, 0-20% Co, 0
~20% W, 0-7% V, 0-10% Mo, 0
It consists of ~3% Cb, 0-3% Hf, 0-1.5% Zr, the remaining amount of nickel and incidental impurities, but in terms of weight it is approximately 0.01% B, 6.44% Re, 3.84% Cr,
5.34%Al, 11.37%Ta, 0.43%C, 3.8%Co, 4.33
%W, 3.01% Mo, balance nickel and incidental impurities (hereinafter referred to as "B" or B-type substrate for presentation purposes)
was prepared as the first substrate. Nickel-based superalloys that can be cast as single crystals by directional solidification and conform to those described in U.S. Pat. , 1-5%
Mo, 3-5% Ti, 3-5% Al, 5-15%
Co, 3-12% W, 2-6% Ta, up to 10%
Re, up to 2% Cb, up to 3% V, up to 2%
Hf, residual amounts of nickel and incidental impurities, further characterized by the substantial absence of C, B and Zr, with an Al:Ti ratio maintained in the range of about 0.5 to about 1, and a Cr:Al ratio A nickel-based superalloy in which the ratio was maintained in a range of about 1.5 to 4 was prepared as a second substrate. This nickel-based superalloy is hereinafter referred to as "N" or N-type substrate for presentation purposes. More specifically, the composition of the second substrate material is nominally by weight: 9.3% Cr, 7.5% Co, 37% Al, 4% Ta;
4.2% Ti, 1.5% Mo, 6% W, 0.5% Nb, residual amount of nickel and incidental impurities. For comparison, each of the B-type and N-type substrates described above was also provided with a typical coating conventionally used to increase the resistance of these types of substrates to environmental degradation. In this case, the chosen coating material is of the type described in U.S. Pat. No. 3,928,026.
NiCoCrAlY (Ni−23Co−18Cr−12.5Al−0.3Y)
It was hot. All NiCoCrAlY type coatings were applied using commercially available equipment using the physical vapor deposition (PVD) method described in the aforementioned US Pat. No. 3,928,026. Prior to the formation of the film, independently of the film,
The B type substrate was solution treated at 1273.9°C (2325〓) for 2 hours, and the N type substrate was solution treated at 1265.5°C (2310〓) for 2 hours. The method of forming the NiCoCrAlY type coating has already been described. The 6M coating was formed by the LPPD plasma spray method described above. For Type B substrates, a commercially available standard internally fed plasma spray gun and the processing parameters listed in Table 1 were used. For type N substrates, a commercially available standard externally fed plasma spray gun and the processing parameters listed in Table 1 were used.

【table】

Table: All coated substrates were subjected to post-spray heat treatment to optimize substrate properties. This heat treatment typically consists of a first aging at 1079.4°C (1975〓) for 2 to 8 hours, followed by a second aging at 898.9°C (1650〓) for 4 to 16 hours. At this stage, the coating is referred to as an "as-coated" coating.
The structure of the B-type substrate is a structure in which aligned eutectic (TaC) fiber reinforcing phases exist in the γ/γ′ matrix, and the structure of the N-type substrate is a structure in which γ′ precipitates exist in the γ matrix. It is. Table 1 shows the results of cyclic oxidation tests conducted on pin samples under the conditions shown using a natural gas flame at the speeds shown. The samples were rotated for uniform exposure and periodically removed from the flame once or six times per hour to cool the samples to approximately 426.6°C (800°C). Failure was defined as the extent to which (substrate) oxidation begins as penetration of the coating. High heat corrosion test at 926.6℃
(1700〓) Using the combustion flame of JP-5 fuel,
5 ppm of salt was added to the combustion products. The samples were rotated for uniform exposure and periodically removed from the flame once every hour. From the table it can be seen that the alloy of the invention as a coating provides good protection for both substrates, especially for Type B substrates. The oxidation resistance provided by the alloy of the present invention is slightly greater than would be expected based on a study of its overall composition. These unexpected properties are due to the absence of titanium and the presence of hafnium in combination with a slightly higher than usual aluminum content (6%) and the right balance of carbon and other refractory metals. This elemental balance helps form and maintain a protective alumina scale when exposed to air. The alloy of the present invention is
Although its high-temperature corrosion resistance is lower than that of NiCoCrAlY, the coating achieves good environmental protection against high-temperature corrosion, i.e., a life of more than 540 hours on type B substrates and a life of more than 1000 hours on type N substrates. The test was completed before damage occurred).

[Table] The coated samples were evaluated metallographically to determine the range of interaction between the coating and the substrate. The results are shown in Table 1. That is, the table shows the extent of erosion and platelet formation areas after exposure to oxidation tests at the temperatures and times indicated, the sum of these areas forming the interaction area. NiCoCrAlY on B and N type substrates

Table 1 Platolets, as shown in FIGS. 3 and 7, respectively, result from interdiffusion of elements between the coating and the substrate, ie, chemical incompatibility between the coating and the substrate. Plaitlets are undesirable because of their acicular form and brittleness. The eroded areas, also shown in FIGS. 3 and 7, are areas where γ' is diluted due to diffusion of elements from the substrate into the coating, leaving a weakened primarily γ matrix. Looking at FIGS. 2 and 6, it can be seen that substantially no interaction zone is observed between the 6M coating and the B-type or N-type substrate in the as-formed state. However, in Figures 1 and 5,
A small area of interaction is seen between the NiCoCrAl coating and the B-type and N-type substrates. Referring to Figures 3 and 4 and Table 1, in the oxidation test, after 500 hours of exposure at 1148.9°C (2100°C), an interaction zone was formed between the NiCoCrAlY coating and the Type B substrate, which was compared to the 6M coating. It can be seen that the interaction zone formed between the substrate and the B-type substrate is approximately three times deeper. Furthermore, in the NiCoCrAlY/B combination approximately 45% of the interaction area consists of the deleterious plaitolite phase. Similarly, referring to Figures 7 and 8 and the table, in the oxidation test, 400
After time exposure, an interaction zone is formed between the NiCoCrAlY coating and the N-type substrate, which is compared to the interaction zone formed between the 6M coating and the N-type substrate, and the 6M/N combination is Despite being subjected to oxidation testing for about 40% longer, it is found to be about 4 times deeper. In the NiCoCrAlY/N combination, about 70% of the interaction area consists of the deleterious platelet phase. In addition to the unique combination of reducing diffusion interactions and providing a favorable environment, the alloy of the present invention
It also has higher high temperature strength than alloys. NiCoCrAlY
982.2°C from high temperature tensile tests performed on extremely thick (approximately 1.27 cm (1/2 inch)) coatings of Type 6M alloy.
(1800〓), the ultimate tensile strength (UTS) of these materials is approximately 48.23 and 206.7 MPa (7
and 30ksi), and at 1093.3°C (2000〓) the UTS of these materials is approximately 20.67 and
It was shown to be 48.23Mpa (3 and 7ksi). It is believed that the high strength of type 6M alloy leads to a significant improvement in thermal/mechanical fatigue crack resistance. Since the alloy of the present invention is itself a superalloy, the difference in coefficient of thermal expansion (α) between the alloy of the present invention and a nickel-based superalloy substrate is less than the difference between NiCoCrAlY and the same superalloy substrate. A small difference in α reduces the stress applied to the coating alloy during use, which reduces the tendency for coating delamination and thermal fatigue cracking. The low tendency of the inventive alloys to form interaction zones, particularly platelets, combined with the high strength and thermal expansion compatibility with the superalloy substrate makes the inventive alloys The alloy not only provides the environmental resistance needed in the harsh high-pressure, high-temperature turbine environment, but also provides a coating that is truly chemically and physically compatible with the nickel-based superalloy substrate. The new alloys of the present invention commonly occur in selected areas of aircraft gas turbine engine components, such as in the form of fairly thick weld metal deposits formed on the tips of rotating blades and stationary vanes, or on components such as airfoil. It has also been found useful for the purpose of repairing defective or damaged areas. In this regard, the alloys of the present invention have greater properties of the superalloys from which the components are made, such as structural or heavy-duty alloys, and lesser properties of the coating. The modifications to the plasma spray method required to form a fairly thick overlay of deposited metal, as opposed to a thin coating, are within the knowledge and skill of one of ordinary skill in the art of plasma spraying. be. Various changes and modifications not specifically mentioned in this specification can be made to the present invention itself and its embodiments without departing from the gist of the present invention.

[Brief explanation of the drawing]

Figure 1 shows the metallographic structure of the NiCoCrAlY type coating on the B type nickel-based eutectic superalloy substrate.
Figure 2 is a 250x micrograph showing the metallographic structure of the alloy of the present invention coated as a film on a type B substrate by low-pressure plasma spraying (LPPD). Figure 3 is a 250x micrograph showing the sample. 426.6℃ 6 times per hour
(800〓) in an oxidation test at a gas velocity of 16.55 m/s (Matsuha 0.05) at 1148.9℃ (2100〓).
NiCoCrAlY on type B substrate after 500 hours of exposure
200x micrograph showing the metallography of the mold coating; Figure 4 shows the metallography of the alloy of the invention on a Type B substrate after 500 hours of exposure in the same oxidation test as described for Figure 3; A 500x micrograph, Figure 5 shows the metallographic structure of the NiCoCrAlY type coating on the N-type nickel-based single crystal superalloy substrate.
Figure 6 is a 500x micrograph showing the metallographic structure of the alloy of the present invention coated as a film on an N-type substrate by the LPPD method. In an oxidation test at a gas velocity of 16.55 m/s (Matsuha 0.05) circulating at
200 showing the metallographic structure of a NiCoCrAlY type coating on an N type substrate after 400 hours of exposure at 1135°C (2075〓)
Magnified micrograph, and Figure 8 shows the same oxidation test described for Figure 7 at 1135°C (2075〓).
Figure 2 is a 200x micrograph showing the metallographic structure of the alloy of the present invention on an N-type substrate after 550 hours of exposure.

Claims (1)

[Claims] 1 1 to 10% cobalt, 6 to 12% by weight
of chromium, 5-8% aluminum, 1-10% tantalum, 1-10% tungsten, 0.1-2%
hafnium, 0.005~0.1% boron, 0.05~
A composition for application to a nickel-based superalloy substrate consisting of 0.25% carbon, balance nickel and incidental impurities. 2 1-10% cobalt, 6-12% by weight
of chromium, 5-8% aluminum, 1-10% tantalum, 1-10% tungsten, up to 3% rhenium, up to 2% molybdenum, 0.1-2% hafnium, 0.005-0.1% boron, 0.005~0.25
% carbon, balance nickel and incidental impurities for application to a nickel-based superalloy substrate. 3 1-6% cobalt, 7-10% by weight
of chromium, 5-7% aluminum, 4-6% tantalum, 3.5-5.5% tungsten, 0.5-1.5
% hafnium, 0.005-0.025% boron, 0.005
A composition according to claim 1 comprising ~0.25% carbon, balance nickel and incidental impurities. 4 1-6% cobalt, 7-10% by weight
of chromium, 5-7% aluminum, 4-6% tantalum, 3.5-5.5% tungsten, up to 3% rhenium, up to 2% molybdenum, 0.5-1.5%
hafnium, 0.005~0.025% boron, 0.005~
A composition according to claim 2 comprising 0.25% carbon, balance nickel and incidental impurities. 5 3.8-4.2% cobalt by weight, 8.3-8.7
% chromium, 5.8~6.2% aluminum, 4.7~
5.3% tantalum, 4.2-4.8% tungsten,
1.2-1.8% rhenium, 1.3-1.7% molybdenum,
5. The composition of claim 4 comprising 0.7-1.1% hafnium, 0.005-0.02% boron, 0.005-0.2% carbon, balance nickel and incidental impurities. 6. A patent claim coated on at least a portion of the outer surface of a nickel-based superalloy or nickel-based eutectic superalloy substrate, having a high degree of substrate compatibility and imparting high temperature oxidation and corrosion resistance to the substrate. A composition according to any one of the ranges 1 to 5. 7. The substrate is made of a composite of a nickel-based superalloy matrix and an aligned fibrous monocarbide eutectic reinforcing phase embedded therein, and the substrate contains boron in an amount greater than the amount of impurities by weight up to 0.02%, 3-15%
of tantalum, 0.1-1% carbon, balance nickel and incidental impurities.
Compositions as described in Section. 8. The substrate is made of a composite of a nickel-based superalloy matrix and an aligned fibrous monocarbide eutectic reinforcing phase embedded therein, and the substrate contains boron in an amount greater than the amount of impurities by weight up to 0.02%, up to 9% rhenium, less than 0.8% titanium, up to 20% chromium, up to 10% aluminum, 3-15% tantalum, 0.1-1% carbon, up to 20% cobalt,
up to 20% tungsten, up to 7% vanadium, up to 10% molybdenum, up to 3% niobium,
7. The composition of claim 6 comprising up to 3% hafnium, up to 1.5% zirconium, balance nickel and incidental impurities. 9 The above substrate contains 0.01% boron by weight, 6.44
% Rhenium, 3.84% Chromium, 5.34% Aluminum, 11.37% Tantalum, 0.43% Carbon, 3.8%
7. The composition of claim 6 comprising % cobalt, 4.33% tungsten, 3.01% molybdenum, balance nickel and incidental impurities. 10 The substrate is made of a nickel-based superalloy that can be cast as a single crystal by directional solidification, and this superalloy contains, by weight, 7 to 12% chromium, 1 to 5% molybdenum, 3 to 5% titanium, and 3 to 5% titanium. Consisting of 5% aluminum, 5-15% cobalt, 3-12% tungsten, 2-6% tantalum, balance nickel and incidental impurities, substantially free of carbon, boron and zirconium; Al:Ti ratio
7. A composition according to claim 6, wherein the Cr:Al ratio is in the range 0.5 to 1 and the Cr:Al ratio is in the range 1.5 to 4. 11 The substrate is made of a nickel-based superalloy that can be cast as a single crystal by directional solidification, and this superalloy contains 7 to 12% chromium, 1 to 5% molybdenum, 3 to 5% titanium, and 3 to 5% titanium by weight. 5% aluminum, 5-15% cobalt, 3-12% tungsten, 2-6% tantalum, up to 10% rhenium, up to 2% niobium, up to 3% vanadium,
up to 2% hafnium, a balance of nickel and incidental impurities, substantially free of carbon, boron and zirconium, with an Al:Ti ratio ranging from 0.5 to 1 and a Cr:Al ratio of 1.5 7. The composition of claim 6 in the range from . 12 The above substrate is 9.3% chromium by weight, 7.5
% cobalt, 3.7% aluminum, 4% tantalum, 4.2% titanium, 1.5% molybdenum, 6%
7. A composition according to claim 6, comprising % tungsten, 0.5% niobium, the balance nickel and incidental impurities. 13. The composition according to any one of claims 1 to 5, which is welded to at least a portion of the outer surface of a nickel-based superalloy or nickel-based eutectic superalloy substrate integrally with the substrate as a thick overlay. thing. 14 The substrate is made of a composite of a nickel-based superalloy matrix and an aligned fibrous monocarbide eutectic reinforcing phase embedded therein, and the substrate contains boron in an amount greater than the amount of impurities by weight up to 0.02%, 3-15
14. The composition of claim 13 comprising % tantalum, 0.1-1% carbon, <0.15% hafnium, balance nickel and incidental impurities. 15 The substrate is made of a composite of a nickel-based superalloy matrix and an aligned fibrous monocarbide eutectic reinforcing phase embedded therein, and the substrate contains boron in an amount greater than the amount of impurities by weight up to 0.02%, up to 9% rhenium, less than 0.8% titanium, up to 20% chromium, up to 10% aluminum, 3-15% tantalum, 0.1-1% carbon, up to 20% cobalt,
up to 20% tungsten, up to 7% vanadium, up to 10% molybdenum, up to 3% niobium,
14. The composition of claim 13 comprising <0.15% hafnium, up to 1.5% zirconium, balance nickel and incidental impurities. 16 The base is made of a composite of a nickel-based superalloy base material and an aligned fibrous monocarbide eutectic reinforcing phase embedded therein, and the base has a weight of 0.01
% boron, 6.44% rhenium, 3.84% chromium, 5.34% aluminum, 11.37% tantalum,
Claim 13 consisting of 0.43% carbon, 3.8% cobalt, 4.33% tungsten, 3.01% molybdenum, balance nickel and incidental impurities.
Compositions as described in Section. 17 The substrate is composed of a nickel-based superalloy that can be cast as a single crystal by directional solidification, and this superalloy contains, by weight, 7 to 12% chromium, 1 to 5% molybdenum, 3 to 5% titanium, 3 ~5% aluminum, 5-15% cobalt, 3-12% tungsten, 2-6% tantalum, balance nickel and incidental impurities, substantially free of carbon, boron and zirconium. 14. The composition of claim 13, wherein the Al:Ti ratio is in the range from 0.5 to 1 and the Cr:Al ratio is in the range from 1.5 to 4. 18 The substrate is composed of a nickel-based superalloy that can be cast as a single crystal by directional solidification, and this superalloy contains 7 to 12% chromium, 1 to 5% molybdenum, 3 to 5% titanium, 3 ~5% aluminum, 5-15% cobalt, 3-12% tungsten, 2-6% tantalum, up to 10% rhenium, up to 2% niobium, up to 3% vanadium, up to 2% hafnium , residual amounts of nickel and incidental impurities, substantially free of carbon, boron and zirconium, with an Al:Ti ratio of 0.5.
to 1, and the Cr:Al ratio is 1.5 to 4.
14. The composition of claim 13, comprising: 19 The above-mentioned substrate consists of a nickel-based superalloy that can be cast as a single crystal by directional solidification, and this superalloy contains 9.3% chromium, 7.5% cobalt, 3.7% aluminum, 4% tantalum, and 4.2% by weight.
14. The composition of claim 13 comprising: % titanium, 1.5% molybdenum, 6% tungsten, 0.5% niobium, the balance nickel and incidental impurities. 20 Claim 13, wherein the base body is a rotating blade or stationary vane of an aircraft gas turbine engine, and the welding area is a tip portion thereof.
Compositions as described in Section.