Nickel-based superalloy containing nanometer strengthening phase and preparation method of nickel-based superalloy

Abstract

The invention provides a nickel-based superalloy containing a nanometer strengthening phase and a preparation method of the nickel-based superalloy, and belongs to the technical field of metal materials. According to the method, the nano carbon material and the nickel-based high-temperature alloy powder are uniformly mixed and then prepared into the alloy by adopting the laser additive manufacturing technology, and the nano carbon material is induced to react in situ in the alloy forming process to form the nano carbide. The nano carbon material and the nano carbide have a second phase strengthening effect on the nickel-based superalloy, so that the performance of the nickel-based superalloy is greatly improved. The prepared nickel-based superalloy containing the nano carbon material is simple in process, environmentally friendly, low in cost and excellent in mechanical property, and has wide application prospects in the fields of aero-engine hot end parts and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of metallic materials, and particularly to a nickel-based superalloy containing nano-strengthening phases and a preparation method thereof. Background Art

[0002] Nickel-based superalloys are widely used in the preparation of hot-end components such as turbine disks, fuel nozzles, and turbine blades of aero-engines and advanced gas turbines due to their excellent mechanical properties at room temperature and high temperature, as well as high-temperature oxidation and hot corrosion resistance. With the continuous development of modern advanced aero-engines and gas turbines, higher and higher requirements are put forward for nickel-based superalloys. In order to meet the growing performance requirements and conform to the development of aero-engines and advanced gas turbines, the performance optimization of nickel-based superalloys is of great significance.

[0003] Carbon nanomaterials include graphene, carbon nanofibers, carbon nanotubes, etc. Due to their excellent electrical and thermal properties, low density, and high strength and elastic modulus, they are often used as strengthening phases to improve the alloy properties. Since carbon nanomaterials such as graphene have a good interfacial relationship with Ni, and the contents of carbide-forming elements such as Mo, W, Cr, Ti, Nb, Ta, etc. in nickel-based superalloys are relatively high, carbon nanomaterials can form carbides through reactions to strengthen the alloy. At the same time, if part of the carbon nanomaterials are retained, it is expected to improve the thermal conductivity of the alloy while increasing the alloy strength, and realize the strengthening of the alloy by the synergistic reaction of nano-carbon particles to induce nano-carbides, which is of great significance for further improving the performance of nickel-based superalloys.

[0004] Compared with the traditional method of directly adding carbon to the master alloy to prepare carbon-containing powders, in the alloy prepared by adding external nano-carbon materials, the carbide size is finer and the distribution is more uniform. The rapidly developing laser additive manufacturing technology is suitable for preparing complex parts, and can achieve one-time forming, without subsequent machining, saving costs. At the same time, due to its process characteristics of forming point by point and layer by layer, highly non-equilibrium metallurgical characteristics and unique sub-micron-scale microstructure of the formed parts, it can effectively promote the uniform distribution of nano-precipitation phases. Based on this, the present invention proposes a nano-carbon material / nano-carbide strengthened nickel-based superalloy, which can significantly improve the performance of nickel-based superalloys. Summary of the Invention

[0005] The purpose of the present invention is to provide a nickel-based superalloy containing nano-strengthening phases and a preparation method thereof. The nano-carbon materials provided by the present invention realize the dispersion distribution of nano-carbon particles and nano-carbides formed by reaction induction in the matrix of nickel-based superalloys, and improve the strength of the alloy. The method has simple process, is green and environmentally friendly, and both the hardness and tensile properties are improved.

[0006] To achieve the above object, the present invention proposes a nickel-based superalloy containing nano-strengthening phases and a preparation method thereof, and its technical solution is as follows:

[0007] The alloy is prepared by laser additive manufacturing technology using a mixture of nano-carbon material and nickel-based high-temperature alloy powder as raw materials; the content of nano-carbon material added to the mixture is 0.02-0.50wt.%, preferably 0.10-0.50wt.%, and more preferably 0.10-0.15wt.%.

[0008] As the preferred technical solution:

[0009] The nickel-based high-temperature alloy containing a nano-strengthening phase can form nano-carbides due to the addition of nano-carbon materials, that is, a nano-scale carbon-containing second phase (including one or more of carbon, tantalum carbide, titanium carbide and niobium carbide) can be formed in the alloy, thereby improving the mechanical properties of the nickel-based high-temperature alloy; the carbon content in the nickel-based high-temperature alloy powder is usually 0.01-0.07wt.%, the primary carbides are blocky or spherical, and the maximum width (the distance between the two farthest points on the surface) is 0.66-1.12μm, which is 4.4-110 times that of nano-carbides. The primary carbides will not be transformed or decomposed into nano-carbides during the laser additive manufacturing process.

[0010] The nanocarbon material includes but is not limited to one or more of nanocarbon fibers, graphene nanosheets and carbon nanotubes, and has a diameter or sheet size of 2nm-130nm and a length of 1μm-30μm. The nanocarbon fibers are cylindrical, with a diameter of 50-100nm and a length of 1-200μm, the graphene nanosheets are lath-shaped, with a sheet diameter of 1-10μm and a thickness of 4-20nm, and the carbon nanotubes are cylindrical, with a tube diameter of 2-3nm and a length of 1-30μm.

[0011] The nickel-based superalloy described above has alloy powder with nickel as the matrix element. By mass fraction, with the mass fraction of nickel element as the remainder, to ensure the formation of nano-carbides, the alloy contains one or two or three of the elements tantalum, titanium, and niobium, and the total composition of these three elements in the alloy is 5.6 - 8.1% (mass fraction, preferably 5.6 - 7.2%); meanwhile, the alloy should also contain cobalt (9% - 25.1%, preferably 9.5% - 21%), tungsten (1.2% - 7.5%, preferably 2% - 7%), aluminum (2.2% - 6.1%, preferably 2.5% - 6%), chromium (3.4% - 13.8%, preferably 3.5% - 13%), molybdenum (0.6% - 2.7%, preferably 0.8% - 2.5%), carbon (0.01% - 0.07%, preferably 0.02% - 0.05%) and other elements; in addition, the alloy does not contain or may also contain but not limited to one or more of rhenium (mass content less than or equal to 4.2%, preferably 0.8% - 3.5%), hafnium (mass content less than or equal to 1.2%, preferably 0.2% - 1.0%), boron (mass content less than or equal to 0.017%, preferably 0.01% - 0.015%), zirconium (mass content less than or equal to 0.027%, preferably 0.02% - 0.025%).

[0012] For the preparation method of the nickel-based superalloy described above, after mixing the nano-carbon material with the nickel-based superalloy powder, it is prepared into an alloy through laser additive manufacturing forming technology to form a nano-scale carbon-containing second phase in the alloy. The content of the nano-carbon material in the mixture is 0.02 - 0.5 wt.%, preferably 0.1 - 0.5 wt.%, more preferably 0.1 - 0.15 wt.%.

[0013] For the preparation method described above, the laser additive manufacturing forming technology is adopted, and the range of the forming parameters used includes: laser power 180 - 360 W (preferably 200 - 300 W), scanning speed 8 - 800 mm / s (preferably 10 - 700 mm / s), laser scanning spacing 0.02 - 0.15 mm (preferably 0.02 - 0.1 mm), and spot diameter 0.1 mm.

[0014] For the preparation method described above, the grain morphology of the prepared nickel-based superalloy is one or more of equiaxed grains, directionally columnar grains, and single crystals; the carbon-containing second phase is formed by the reaction of the added nano-carbon material with the alloy powder during the forming process; the size of the second phase is nanoscale, spherical, with a size of 10 nm - 150 nm.

[0015] For the preparation method described above, the carbon-containing second phase includes but is not limited to one or more of nano-carbon materials and nano-carbides; the carbide is of the MC type and includes but is not limited to one or more of titanium carbide, tantalum carbide, and niobium carbide.

[0016] The described preparation method forms a carbon-containing second phase at the nanoscale in the alloy, thereby improving the mechanical properties of the nickel-based superalloy. The mechanical properties refer to the hardness, tensile properties, high-temperature creep properties, etc. of the alloy.

[0017] In the present invention, after uniformly mixing the nanocarbon material with the nickel-based superalloy powder, the alloy is prepared by laser additive manufacturing technology, inducing in-situ reaction of the nanocarbon material during the alloy forming process to form nanocarbonides. The nanocarbon material and nanocarbonides have a second-phase strengthening effect on the nickel-based superalloy, greatly improving the performance of the nickel-based superalloy. The nickel-based superalloy containing nanocarbon material prepared by the present invention has a simple process, is green and environmentally friendly, has a low cost, excellent mechanical properties, and has broad application prospects in fields such as hot-end components of aeroengines. Brief Description of the Drawings

[0018] Figure 1 SEM and TEM images of nanocarbonides in a nickel-based single-crystal superalloy containing 0.02 wt% carbon nanofibers in Example 1;

[0019] Figure 2 SEM and TEM images of nanocarbonides in a nickel-based single-crystal superalloy containing 0.05 wt% carbon nanofibers in Example 2;

[0020] Figure 3 SEM and TEM images of nanocarbonides in a nickel-based directionally solidified columnar crystal superalloy containing 0.1 wt% graphene nanosheets in Example 3;

[0021] Figure 4 SEM and TEM images of nanocarbonides in a nickel-based polycrystalline superalloy containing 0.5 wt% carbon nanotubes in Example 4. Detailed Embodiments

[0022] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0023] Example 1

[0024] A nickel-based single-crystal (characterized by EBSD) superalloy strengthened by carbon nanofibers in cooperation with nanocarbonides and its preparation method specifically include the following operation steps:

[0025] Preparation of reinforced high-temperature alloy: Industrially applied carbon nanofibers and nickel-based high-temperature alloy powders were mixed at mass fractions of 0.02wt.% and 99.98wt.% respectively (as raw materials), the carbon nanofibers used were cylindrical, with a diameter of 50-100nm and a length of 1-100μm, the high-temperature alloy powder particle size was 15-58μm, and the nickel-based high-temperature alloy powder composition was shown in Table 1. The mixed powder was formed by the selective laser melting technology in the laser additive manufacturing forming technology, with a laser power of 300W, a scanning speed of 8mm / s, a laser scanning interval of 0.02mm, and a spot diameter of 0.1mm. A nickel-based single crystal (characterized by EBSD) high-temperature alloy containing a nanocarbide strengthening phase was prepared; the high-temperature alloy was in a block shape with a size of 60 mm (length) × 20 mm (width) × 3 mm (height), the nanocarbides in the alloy were spherical with a particle size of 30-150 nm, the carbides were (Ta, Ti) C, and the area fraction of the nanocarbides was measured by SEM images and Image pro plus software to be 26% (based on the area fraction of the nanocarbides per unit field of view obtained by measuring the nanocarbides under a scanning electron microscope). In addition, there were blocky primary carbides (Ta, Ti) C, and the maximum width (the distance between the two farthest points on the surface) was 0.83-1.10 μm, such as Figure 1 As shown. The Vickers hardness and room temperature mechanical properties of the strengthened alloy were tested based on GB / T4340.1 and GB / T228.1 respectively, and the hardness of the strengthened alloy was 450±7HV, which was 19% higher than that of the original laser additive manufacturing alloy (the original laser additive manufacturing alloy is made of nickel-based high-temperature alloy powder as raw material, and the other process conditions are the same as the preparation of the above strengthened high-temperature alloy. It can be seen from the scanning electron microscope that it contains primary carbides (Ta, Ti) C, and the distance between the two farthest points on the surface of the primary carbide is 0.78-1.12μm, but it does not contain nanocarbides, and the content, morphology and size of the primary carbides are equivalent to or the same as those in the above high-temperature alloy. This is because the initial nickel-based high-temperature alloy powder contains carbon, which precipitates during the solidification process, and the content is related to the carbon content in the initial alloy powder) 377±10HV. The room temperature tensile strength of the strengthened alloy is 1448±34MPa, which is 5.6% higher than that of the original laser additively manufactured alloy (1370±4MPa).

[0026] The alloy system includes: γ matrix, primary carbides (large size), and nanocarbides (nanoscale); primary carbides are spontaneously precipitated from the carbon elements contained in the alloy powder during the solidification process, and nanocarbides are generated by the reaction of added nanocarbon particles and alloy powder during the forming process.

[0027] Table 1 Composition of nickel-based superalloy powder used to prepare carbon nanofiber reinforced nickel-based single crystal superalloy

[0028]

[0029] Example 2

[0030] A carbon nanofiber-coordinated nanocarbide-reinforced nickel-based single crystal (characterized by EBSD) high-temperature alloy and a preparation method thereof, specifically comprising the following steps:

[0031] Preparation of reinforced high-temperature alloy: Industrially applied carbon nanofibers and nickel-based high-temperature alloy powders were mixed at mass fractions of 0.05wt.% and 99.95wt.% respectively (as raw materials), the carbon nanofibers used were cylindrical, with a diameter of 50-100nm and a length of 1-200μm, the high-temperature alloy powder particle size was 15-58μm, and the nickel-based high-temperature alloy powder composition was shown in Table 2. The mixed powder was formed by the selective laser melting technology in the laser additive manufacturing forming technology, with a laser power of 360W, a scanning speed of 8mm / s, a laser scanning spacing of 0.06mm, and a spot diameter of 0.1mm. A nickel-based single crystal (characterized by EBSD) high-temperature alloy containing a nanocarbide strengthening phase was prepared; the high-temperature alloy was in a block shape with a size of 60 mm (length) × 20 mm (width) × 3 mm (height); the nanocarbides in the alloy were spherical with a particle size of 40-150 nm; the carbides were TaC; the area fraction of the carbides was measured by SEM images and Image pro plus software to be 29% (based on the area fraction of the nanocarbides per unit field of view obtained by measuring the nanocarbides under a scanning electron microscope); in addition, there were blocky primary carbides of TaC, with a maximum width (the distance between the two farthest points on the surface) of 0.83-0.93 μm, such as Figure 2 As shown. The Vickers hardness and room temperature mechanical properties of the strengthened alloy were tested based on GB / T4340.1 and GB / T228.1 respectively, and the hardness of the strengthened alloy was 357±10HV, which was 13% higher than that of the original laser additive manufacturing alloy (the original laser additive manufacturing alloy is made of nickel-based high-temperature alloy powder as raw material, and the other process conditions are the same as the preparation of the above strengthened high-temperature alloy. It can be seen from the scanning electron microscope that it contains primary carbides TaC, and the distance between the two farthest points on the surface of the primary carbides is 0.85-1.06μm, but it does not contain nanocarbides, and the content, morphology and size of the primary carbides are equivalent to or the same as those in the above high-temperature alloy. This is because the initial nickel-based high-temperature alloy powder contains carbon, which precipitates during the solidification process, and the content is related to the carbon content in the initial alloy powder). The room temperature tensile strength of the strengthened alloy is 1366±5MPa, which is 28% higher than that of the original laser additive manufacturing alloy 1069±4MPa.

[0032] The alloy system includes: γ matrix, primary carbides (large size), and nanocarbides (nanoscale); primary carbides are spontaneously precipitated from the carbon elements contained in the alloy powder during the solidification process, and nanocarbides are generated by the reaction of added nanocarbon particles and alloy powder during the forming process.

[0033] Table 2 Alloy powder composition used to prepare carbon nanofiber reinforced nickel-based single crystal high-temperature alloy

[0034]

[0035] Example 3

[0036] A graphene nanosheet-coordinated nanocarbide-reinforced nickel-based oriented columnar crystal (characterized by EBSD) high-temperature alloy and a preparation method thereof, specifically comprising the following steps:

[0037] Preparation of reinforced high-temperature alloy: industrially applied graphene nanosheets and nickel-based high-temperature alloy powders were mixed at mass fractions of 0.1wt.% and 99.9wt.% respectively (as raw materials). The graphene nanosheets used were in the form of laths, with a length of 1-10μm, a width of 2-6μm, and a thickness of 4-20nm. The particle size of the high-temperature alloy powder was 15-58μm. The composition of the nickel-based high-temperature alloy powder used was shown in Table 3. The mixed powder was formed by the selective laser melting technology in the laser additive manufacturing forming technology. The laser power used was 350W, the scanning speed was 10mm / s, the laser scanning interval was 0.15mm, and the spot diameter was 0.1mm. A nickel-based single crystal (characterized by EBSD) high-temperature alloy containing a nanocarbide strengthening phase was prepared; the high-temperature alloy was in a block shape with a size of 60 mm (length) × 20 mm (width) × 3 mm (height), the nanocarbides in the alloy were spherical with a particle size of 30-100 nm, the carbides were (Ti, Ta) C, and the area fraction of the carbides was measured by SEM images and Image pro plus software to be 55% (based on the area fraction of the nanocarbides per unit field of view obtained by measuring the nanocarbides under a scanning electron microscope). In addition, there were also flaky primary carbides (Ti, Ta) C, with a maximum width (the distance between the two farthest points on the surface) of 0.73-0.89 μm, such as Figure 3As shown. The Vickers hardness and room temperature mechanical properties of the formed alloy were tested based on GB / T4340.1, GB / T228.1 and GB2039 respectively. The hardness of the strengthened alloy was 499±12HV, which was 28% higher than that of the laser additive manufactured alloy with the original composition (the laser additive manufactured alloy with the original composition was made of nickel-based superalloy powder, and the remaining process conditions were the same as those for the preparation of the strengthened superalloy. It could be seen from the scanning electron microscope that it contained primary carbide (Ti,Ta)C, and the farthest distance between two points on the surface of the primary carbide was 0.68 - 1.02μm, and it did not contain nano-carbide, and the content, morphology and size of the primary carbide were equivalent or the same as those of the primary carbide in the above superalloy. This was because the initial nickel-based superalloy powder contained carbon, which precipitated during the solidification process, and the content was related to the carbon content in the initial alloy powder) 391±13HV. The room temperature tensile strength of the strengthened alloy was 1429±24MPa, which was 40% higher than that of the original alloy 1021±17MPa. The high temperature creep life of the strengthened alloy at 900°C / 200MPa was 26±3h, which was 37% longer than that of the original alloy 19±2h.

[0038] The alloy system altogether includes: γ matrix, primary carbide (large size), nano-carbide (nano-scale); among them, the primary carbide is spontaneously precipitated from the carbon element contained inside the alloy powder during the solidification process, and the nano-carbide is formed by the reaction of the added nano-carbon particles and the alloy powder during the forming process.

[0039] Table 3 Composition of alloy powder used to prepare graphene nanosheet strengthened nickel-based superalloy

[0040]

[0041] Example 4

[0042] A carbon nanotube co - strengthened nickel-based equiaxed crystal (characterized by EBSD) superalloy and its preparation method, specifically including the following operation steps:

[0043] Preparation of reinforced high-temperature alloy: Industrial carbon nanotubes and nickel-based high-temperature alloy powders were mixed at mass fractions of 0.5wt.% and 99.5wt.% respectively (as raw materials). The carbon nanotubes used were cylindrical, with an outer diameter of 4-6nm, an inner diameter of 1-3nm, and a length of 1-30μm. The particle size of the high-temperature alloy powder was 15-58μm. The composition of the nickel-based high-temperature alloy powder was shown in Table 4. The mixed powder was formed by the selective laser melting technology in the laser additive manufacturing forming technology. The laser power used was 180W, the scanning speed was 800mm / s, the laser scanning spacing was 0.1mm, and the spot diameter was 0.1mm. A nickel-based single crystal (characterized by EBSD) high-temperature alloy containing nanocarbide strengthening phase was obtained; the high-temperature alloy was in block shape, with a size of 60mm (length) × 20mm (width) × 3mm (height), the nanocarbides in the alloy were spherical, with a particle size of 10-150nm, and the carbides were (Ti, Nb) C. The area fraction of carbides was measured by SEM images and Image pro plus software to be 73% (based on the area fraction of nanocarbides per unit field of view obtained by measuring nanocarbides under a scanning electron microscope), but there were still carbon nanotubes remaining at the grain boundaries. In addition, there were also flaky primary carbides (Ti, Nb) C, with a maximum width (the distance between the two farthest points on the surface) of 0.66-0.78μm, such as Figure 4 As shown. The Vickers hardness and room temperature mechanical properties of the formed alloy were tested based on GB / T4340.1 and GB / T228.1 respectively, and the hardness of the strengthened alloy was 495±14HV, which was 25% higher than that of the original laser additive manufacturing alloy (the original laser additive manufacturing alloy was made of nickel-based high-temperature alloy powder as raw material, and the other process conditions were the same as the preparation of the above strengthened high-temperature alloy. The scanning electron microscope showed that it contained primary carbides (Ti, Nb) C, and the distance between the two farthest points on the surface of the primary carbide was 0.77-0.89μm, but it did not contain nanocarbides, and the content, morphology and size of the primary carbides were equivalent to or the same as those in the above high-temperature alloy. This is because the initial nickel-based high-temperature alloy powder contains carbon, which precipitates during the solidification process, and the content is related to the carbon content in the initial alloy powder). The room temperature tensile strength of the strengthened alloy is 1456±7MPa, which is 36% higher than that of the original alloy 1074±5.5MPa.

[0044] The alloy system includes: γ matrix, primary carbides (large size), and nanocarbides (nanoscale); primary carbides are spontaneously precipitated from the carbon elements contained in the alloy powder during the solidification process, and nanocarbides are generated by the reaction of added nanocarbon particles and alloy powder during the forming process.

[0045] Table 4 Alloy powder composition used to prepare carbon nanotube reinforced nickel-based high-temperature alloy

[0046]

Claims

1. A nickel-based high-temperature alloy containing a nano-strengthening phase, characterized in that: The alloy is prepared by laser additive manufacturing technology using a mixture of nano-carbon material and nickel-based high-temperature alloy powder as raw materials; The content of the nano-carbon material added to the mixture is 0.02-0.50 wt.%, preferably 0.10-0.50 wt.%, and more preferably 0.10-0.15 wt.%.

2. The nickel-based high-temperature alloy containing nano-strengthening phase according to claim 1, characterized in that: Since the addition of nano-carbon materials can form nano-carbides, a nano-scale carbon-containing second phase (including one or more of carbon, tantalum carbide, titanium carbide and niobium carbide) can be formed in the alloy, thereby improving the mechanical properties of the nickel-based high-temperature alloy; The carbon content in nickel-based high-temperature alloy powder is usually 0.01-0.07wt.%, and the primary carbides are blocky or spherical, with a maximum width (the distance between the two farthest points on the surface) of 0.66-1.12μm, which is 4.4-110 times that of nanocarbides. Primary carbides will not transform or decompose into nanocarbides during the laser additive manufacturing process.

3. The nickel-based high-temperature alloy according to claim 1, characterized in that: The nanocarbon material includes but is not limited to one or more of nanocarbon fibers, graphene nanosheets or carbon nanotubes; The nano-carbon fiber is cylindrical, with a diameter of 50-100nm (preferably 50-80nm) and a length of 1-200μm (preferably 1-100μm); the graphene nanosheet is lath-shaped, with a length of 1-10μm (preferably 1-5μm), a width of 2-6μm (preferably 2-4μm), and a thickness of 4-20nm (preferably 6-10nm); the carbon nanotube is cylindrical, with an outer diameter of 4-6nm (preferably 4-5nm), an inner diameter of 1-3nm (preferably 1-2nm), and a length of 1-30μm (preferably 1-10μm).

4. The nickel-based high-temperature alloy according to claim 1, characterized in that: The nickel-based high-temperature alloy powder uses nickel as the matrix element, and the nickel element mass fraction is the balance. To ensure the formation of nano-carbides, the alloy contains one, two or three elements of tantalum, titanium and niobium, and the total composition of these three elements in the alloy is 5.6-8.1% (mass fraction, preferably 5.6-7.2%). At the same time, the alloy should also contain cobalt (9%-25.1%, preferably 9.5%-21%), tungsten (1.2%-7.5%, preferably 2%-7%), aluminum (2.2%-6.1%, preferably 2.5%-6%), chromium (3.4%-13.8%, preferably 3.5%-13%), molybdenum (0.6%-2.7%, preferably 0.8%-2.5%), carbon (0.01%-0.07%, preferably 0.02%-0.05%) elements; In addition, the alloy does not contain or may also contain but is not limited to one or more elements of rhenium (mass content is less than or equal to 4.2%, preferably 0.8%-3.5%), hafnium (mass content is less than or equal to 1.2%, preferably 0.2%-1.0%), boron (mass content is less than or equal to 0.017%, preferably 0.01%-0.015%), and zirconium (mass content is less than or equal to 0.027%, preferably 0.02%-0.025%).

5. A method for preparing the nickel-based high-temperature alloy according to any one of claims 1 to 4, characterized in that: After the nano-carbon material is mixed with nickel-based high-temperature alloy powder, an alloy is prepared by laser additive manufacturing technology to form a nano-scale carbon-containing second phase in the alloy. The content of the nano-carbon material in the mixture is 0.02-0.5wt.%, preferably 0.1-0.5wt.%, and more preferably 0.1-0.15wt.%.

6. The preparation method according to claim 5, characterized in that: Laser additive manufacturing forming technology is adopted, and the forming parameter range used includes: laser power 180-360W (preferably 200-300W), scanning speed 8-800mm / s (preferably 10-700mm / s), laser scanning spacing 0.02-0.15mm (preferably 0.02-0.1mm), and spot diameter 0.1mm.

7. The preparation method according to claim 5, characterized in that: The grain morphology of the prepared nickel-based high-temperature alloy is one or more of equiaxed crystals, oriented columnar crystals and single crystals; The carbon-containing second phase is generated by the reaction of the added nano-carbon material with the alloy powder during the forming process; The size of the second phase is nanoscale, spherical, and has a size of 10nm-150nm.

8. The preparation method according to claim 5 or 7, characterized in that: The carbon-containing second phase includes but is not limited to one or more of nanocarbon materials and nanocarbides; The carbide is of MC type, including but not limited to one or more of titanium carbide, tantalum carbide and niobium carbide.

9. The preparation method according to claim 5, characterized in that: A nanoscale carbon-containing second phase is formed in the alloy, thereby improving the mechanical properties of the nickel-based high-temperature alloy. The mechanical properties refer to the hardness, tensile properties and high-temperature durability of the alloy.

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