A high cobalt and gamma apos; high-content nickel-based superalloy and preparation method and application thereof

Abstract

The invention provides a nickel-based superalloy with high cobalt and gamma'content and a preparation method and application thereof, and belongs to the technical field of superalloy additive manufacturing. The invention provides spherical nickel-based high-temperature alloy powder which comprises the following components in percentage by mass: 20 to 30 percent of Co, 8 to 10 percent of Cr, 4 to 7 percent of Al + Ti, 14 to 16 percent of W + Mo + Ta, 0 to 3.5 percent of Nb, 0.001 to 0.015 percent of B, 0.05 to 0.1 percent of C and the balance of Ni. And the spherical nickel-based superalloy powder serves as a printing raw material, laser additive manufacturing is conducted, then heat treatment is conducted, and the nickel-based superalloy with the high cobalt content and the high gamma'content is obtained. The nickel-based superalloy with high cobalt and gamma'content prepared by the method has excellent high-temperature mechanical properties and excellent printability, and is suitable for direct forming of turbine blades or additive manufacturing repair of damaged turbine blades.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-temperature alloy additive manufacturing, and particularly relates to a high-cobalt and gamma-prime content nickel-based high-temperature alloy and a preparation method and application thereof. BACKGROUND

[0002] The nickel-based high-temperature alloy is widely applied to components under extreme working conditions such as turbine blades of an aero-engine due to excellent high-temperature strength, creep resistance and corrosion resistance. The turbine blade often faces problems such as wear, crack and surface degradation during service, and the traditional replacement of the whole component is costly. The additive manufacturing technology provides an efficient solution for repairing the damaged turbine blade, and can prolong the service life by restoring the aerodynamic shape, microstructure and mechanical properties. However, the additive manufacturing of the nickel-based high-temperature alloy faces inherent contradictions between process and mechanical properties. The high-temperature strength needs to be improved by increasing the Al, Ti or Ta element content to increase the volume fraction of gamma prime phase, but the high Al, Ti and Ta content will expand the solidification temperature interval of the alloy, resulting in cracks in the additive manufacturing process. The existing high-strength high-temperature alloy (such as IN738LC) is designed for investment casting, and cannot adapt to the rapid cooling and high thermal stress in the additive manufacturing process, and the crack sensitivity is significantly increased, which seriously restricts the application of the additive manufacturing technology in key high-temperature components such as turbine blades.

[0003] In order to balance the additive manufacturing process and mechanical properties of the nickel-based high-temperature alloy, the current research mainly adopts two strategies: (1) reducing the Al, Ti and Ta content to reduce the gamma prime phase content, which can inhibit cracks, but will cause a significant decrease in high-temperature mechanical properties, and cannot meet the requirements of high-temperature strength and creep resistance of the turbine blade; (2) increasing the Co content to 30-40 at.%, and developing a crack-free CoNi-based high-temperature alloy for additive manufacturing by widening the gamma / gamma prime two-phase region, however, the addition of Co will reduce the thermal stability of the gamma prime phase, resulting in a decrease in high-temperature mechanical properties. SUMMARY

[0004] The present application aims to provide a high-cobalt and gamma-prime content nickel-based high-temperature alloy and a preparation method and application thereof. The high-cobalt and gamma-prime content nickel-based high-temperature alloy prepared by the method has excellent high-temperature mechanical properties and excellent printability, and is suitable for directly forming a turbine blade or additive manufacturing repair of a damaged turbine blade.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions: The application provides a preparation method of a high-cobalt and high-gamma' content nickel-based superalloy, comprising the following steps: providing a spherical nickel-based superalloy powder, the composition of the spherical nickel-based superalloy powder comprises, in terms of mass content, Co: 20-30%, Cr: 8-10%, Al+Ti: 4-7%, W+Mo+Ta: 14-16%, Nb: 0-3.5%, B: 0.001-0.015%, C: 0.05-0.1%, and the balance is Ni; using the spherical nickel-based superalloy powder as a printing raw material to perform laser additive manufacturing to obtain a printed alloy; the laser additive manufacturing mode comprises laser direct energy deposition printing forming or laser powder bed fusion printing forming; and performing heat treatment on the printed alloy to obtain the high-cobalt and high-gamma' content nickel-based superalloy. By adding high-content Al, Ti and Ta elements, high-volume-fraction gamma' phases are introduced to ensure the high-temperature mechanical properties of the alloy, high-content Co elements are added, the gamma / gamma' two-phase region is widened, the solidification temperature range is reduced, the printability of the alloy is significantly improved, the cracking problem caused by high-content Al, Ti and Ta elements is solved, the alloy can be directly formed into a turbine blade or used for additive manufacturing repair of a damaged turbine blade, and the alloy is suitable for large-scale industrial promotion.

[0006] Further, the application introduces dispersed Y2O3 nanoparticles by increasing the cobalt content to ensure the additive manufacturability, can hinder dislocation movement, inhibit grain boundary migration, can further improve the high-temperature mechanical properties of the nickel-based superalloy, and is suitable for directly forming a turbine blade or performing additive manufacturing repair of a damaged turbine blade.

[0007] Further, the application mixes the spherical nickel-based superalloy powder and Y2O3 nanoparticles by using an acoustic resonance mixer, uniformly attaches the nanoscale Y2O3 particles to the surface of the micron-scale spherical nickel-based superalloy powder through the joint action of macroscopic mixing flow, microscopic strong mixing flow and longitudinal acoustic waves, does not damage the sphericity of the powder, solves the problem of dispersion of Y2O3 nanoparticles in laser additive manufacturing, makes the Y2O3 nanoparticles uniformly and dispersedly distributed in the nickel-based superalloy, and the obtained alloy has excellent high-temperature mechanical properties and is suitable for directly forming a turbine blade or performing additive manufacturing repair of a damaged turbine blade. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 It is a light microscope photo of the LDED printed alloy in Example 1; Figure 2 It is a light microscope photo of the LPBF printed alloy in Example 1; Figure 3 It is a scanning electron microscope photo of the LDED aged alloy and the LPBF aged alloy in Example 1; Figure 4Scanning electron micrograph of the LDED as-printed alloy of Example 2; Figure 5 Optical micrograph of the LDED as-printed alloy of Example 2; Figure 6 Scanning electron micrograph of the LDED aged alloy of Example 2; Figure 7 Optical micrograph of the LDED hot isostatic pressed alloy of Example 2; Figure 8 Optical micrograph of the LDED as-printed alloy of Example 3; Figure 9 Optical micrograph of the LPBF as-printed alloy of Example 3; Figure 10 Scanning electron micrograph of the LDED aged alloy and the LPBF aged alloy of Example 3; Figure 11 Optical micrograph of the LDED as-printed alloy of Example 4; Figure 12 Scanning electron micrograph of the LDED aged alloy of Example 4; Figure 13 Optical micrograph of the LPBF as-printed alloy of Comparative Example 1. DETAILED DESCRIPTION

[0009] The present application provides a preparation method of a high cobalt and gamma prime content nickel-based superalloy, comprising the following steps: A spherical nickel-based superalloy powder is provided, the components of the spherical nickel-based superalloy powder include, in terms of mass content, Co: 20-30%, Cr: 8-10%, Al+Ti: 4-7%, W+Mo+Ta: 14-16%, Nb: 0-3.5%, B: 0.001-0.015%, C: 0.05-0.1%, and the balance is Ni; The spherical nickel-based superalloy powder is used as a printing raw material to perform laser additive manufacturing to obtain an as-printed alloy; the laser additive manufacturing method includes laser direct energy deposition printing forming or laser powder bed fusion printing forming; The as-printed alloy is subjected to heat treatment to obtain the high cobalt and gamma prime content nickel-based superalloy.

[0010] In the present application, unless otherwise specified, the raw materials used are commercially available products or are prepared by methods well known to those skilled in the art.

[0011] The present application provides a spherical nickel-based superalloy powder, the composition of the spherical nickel-based superalloy powder includes, in terms of mass content: Co: 20-30%, Cr: 8-10%, Al+Ti: 4-7%, W+Mo+Ta: 14-16%, Nb: 0-3.5%, B: 0.001-0.015%, C: 0.05-0.1%, and the balance is Ni. Details are described below.

[0012] The composition of the spherical nickel-based superalloy powder according to the present application includes Co 20-30%, specifically 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%, in terms of mass percentage.

[0013] The composition of the spherical nickel-based superalloy powder according to the present application includes Cr 8-10%, specifically 8%, 8.3%, 8.5%, 8.7%, 9%, 9.3%, 9.5%, 9.7% or 10%, in terms of mass percentage.

[0014] The composition of the spherical nickel-based superalloy powder according to the present application includes Al+Ti, totaling 4-7%, specifically 4%, 4.5%, 5%, 5.5%, 6%, 6.5% or 7%, in terms of mass percentage. As an embodiment of the present application, the mass content of Al in the spherical nickel-based superalloy powder can be 4-6%, specifically 4%, 4.5%, 5%, 5.5% or 6%; the mass content of Ti can be 0.5-2%, specifically 0.5%, 1%, 1.5% or 2%.

[0015] The composition of the spherical nickel-based superalloy powder according to the present application includes W+Mo+Ta, totaling 14-16%, specifically 14%, 14.5%, 15%, 15.5% or 16%, in terms of mass percentage. As an embodiment of the present application, the mass content of W in the spherical nickel-based superalloy powder can be 4-7%, specifically 4%, 4.5%, 5%, 5.5%, 6%, 6.5% or 7%; the mass content of Mo can be 1-4%, specifically 1%, 1.5%, 2%, 2.5%, 3%, 3.5% or 4%; the mass content of Ta can be 5-8%, specifically 5%, 5.5%, 6%, 6.5%, 7%, 7.5% or 8%.

[0016] The composition of the spherical nickel-based superalloy powder according to the present application includes Nb 0-3.5%, specifically 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3% or 3.5%, in terms of mass percentage.

[0017] The ball-shaped nickel-based superalloy powder according to the present application contains B in an amount of 0.001-0.015% by mass, and specifically, 0.001%, 0.005%, 0.01% or 0.015%.

[0018] The ball-shaped nickel-based superalloy powder according to the present application contains C in an amount of 0.05-0.1% by mass, and specifically, 0.05%, 0.07%, 0.09% or 0.1%.

[0019] The ball-shaped nickel-based superalloy powder according to the present application contains the balance of Ni.

[0020] The ball-shaped nickel-based superalloy powder according to the present application contains high amounts of Al, Ti and Ta, which are intended to precipitate high-volume γ' phase during subsequent heat treatment, so as to ensure that the final nickel-based superalloy has excellent high-temperature mechanical properties. In addition, the ball-shaped nickel-based superalloy powder according to the present application contains high amounts of Co, which is intended to widen the γ / γ' two-phase region and narrow the solidification temperature range, so as to improve the printability of the nickel-based superalloy. The introduction of Nb into the ball-shaped nickel-based superalloy powder according to the present application can promote the formation of γ' phase.

[0021] As an embodiment of the present application, the particle size of the ball-shaped nickel-based superalloy powder can be 10-120 μm, and specifically, 10-53 μm or 53-120 μm, so as to meet the requirements of different laser additive manufacturing methods. The preparation method of the ball-shaped nickel-based superalloy powder comprises the following steps: After the ball-shaped nickel-based superalloy powder is proportioned according to the composition, suspension induction melting and casting are performed to obtain a master alloy ingot. The master alloy ingot is machined to obtain a master alloy electrode rod. The master alloy electrode rod is used as a raw material to perform powdering by using a plasma rotating electrode atomization method, so as to obtain the ball-shaped nickel-based superalloy powder.

[0022] After the ball-shaped nickel-based superalloy powder is proportioned according to the composition, suspension induction melting and casting are performed to obtain a master alloy ingot. As an embodiment of the present application, the preparation raw material of the ball-shaped nickel-based superalloy powder can comprise metal raw material, carbon raw material and boron raw material. The metal raw material can comprise Ni particles, Co particles, Cr particles, Al particles, Ti particles, Ta bulk, Mo particles and W bulk. When the ball-shaped nickel-based superalloy powder contains Nb, the metal raw material further comprises Nb bulk. The carbon raw material can be graphite particles, and the boron raw material can be B particles. As an embodiment of the present application, the purity of the metal raw material, carbon raw material and boron raw material is preferably >99.95wt%.

[0023] As an embodiment of the present application, the number of times of the suspension induction melting is preferably 3-5, and each of the suspension induction melting independently comprises: heating the raw material for preparing the spherical nickel-based superalloy powder at a power of 90-110 kW for 8-12 min, then increasing the power to 190-210 kW to completely melt the raw material, and finally decreasing the power to 140-160 kW for 8-12 min; specifically, the raw material for preparing the spherical nickel-based superalloy powder can be heated at a power of 100 kW for 10 min, then the power is increased to 200 kW to completely melt the raw material, and finally the power is decreased to 150 kW for 10 min. As an embodiment of the present application, the suspension induction melting preferably further comprises: before the suspension induction melting, the vacuum in the furnace is pumped to ≤7×10 -3 Pa, and then the working gas (argon, purity ≥99.99%) is filled to 0.2-0.3 MPa. The suspension induction melting under the above conditions in the present application is beneficial to obtain the master alloy ingot with high purity and high uniformity.

[0024] As an embodiment of the present application, the temperature of the casting can be 1450-1500 ℃, and specifically can be 1450 ℃, 1460 ℃, 1470 ℃, 1480 ℃, 1490 ℃ or 1500 ℃. As an embodiment of the present application, the size of the master alloy ingot can be Φ 35 mm (diameter) × 200 mm (length); and the impurity element content of the master alloy ingot is preferably <5 ppm.

[0025] After obtaining the master alloy ingot, the master alloy ingot is machined to obtain a master alloy electrode rod. As an embodiment of the present application, the diameter of the master alloy electrode rod can be 30 mm, and the length can be 160-200 mm; in the present application, the size of the master alloy electrode rod is specifically Φ 30 mm × 160 mm. As an embodiment of the present application, the machining is preferably performed after the riser of the master alloy ingot is cut off. The method of the machining is not particularly limited in the present application, and a method well known to those skilled in the art can be used to obtain the master alloy electrode rod meeting the above size requirements.

[0026] After obtaining the master alloy electrode rod, the present application adopts plasma rotating electrode atomization method to carry out powdering with the master alloy electrode rod as raw material, and obtains the spherical nickel-based high-temperature alloy powder. As an embodiment of the present application, the conditions of the plasma rotating electrode atomization method include that the main arc current can be 600-800 A, and specifically can be 700 A; the auxiliary arc current can be 90-110 A, and specifically can be 100 A; the rotating speed of the master alloy electrode rod can be 15000-20000 r / min, and specifically can be 15000 r / min, 16000 r / min, 17000 r / min, 18000 r / min, 19000 r / min or 20000 r / min; the feeding speed can be 1-3 mm / s, and specifically can be 1.2 mm / s or 1.5 mm / s; the flow rate of the working gas can be 9-11 L / min, and specifically can be 10 L / min; the working gas can be specifically argon, and the purity of the argon can be ≥99.99%. As an embodiment of the present application, the powdering preferably further includes: vacuumizing the atomization chamber to ≤5×10 -3 Pa, and then filling the working gas to a working pressure of 0.04-0.06 MPa. In the embodiment of the present application, the plasma rotating electrode atomization method is adopted to carry out powdering under the above conditions, so as to ensure that the finally obtained spherical nickel-based high-temperature alloy powder has the characteristics of uniform composition, controllable and narrow distribution range of particle size, good sphericity, low O and N content, high purity, and no satellite powder. In the embodiment of the present application, specifically, the master alloy electrode rod is installed on the rotating electrode shaft of the plasma rotating electrode device, and under the high-speed rotating state, the plasma beam generated by the plasma generator melts the end part of the master alloy electrode rod, the molten alloy is atomized into droplets under the action of centrifugal force, and then is cooled and solidified in the working gas protection atmosphere, so as to finally obtain the spherical nickel-based high-temperature alloy powder.

[0027] As an embodiment of the present application, the powdering preferably further includes screening, and the spherical nickel-based high-temperature alloy powder with a particle size of 10-53 μm and the spherical nickel-based high-temperature alloy powder with a particle size of 53-120 μm are obtained respectively; wherein the yield of the spherical nickel-based high-temperature alloy powder with a particle size of 10-53 μm can be 50%, and the yield of the spherical nickel-based high-temperature alloy powder with a particle size of 53-120 μm can be 50%. As an embodiment of the present application, the screening preferably further includes drying, and the drying can be vacuum drying; the temperature of the drying can be 120 ℃, and the time can be 2 h.

[0028] After obtaining the spherical nickel-based superalloy powder, the present application uses the spherical nickel-based superalloy powder as a printing raw material to carry out laser additive manufacturing to obtain a printed alloy. In the present application, the method of laser additive manufacturing includes laser direct energy deposition (LDED) printing forming or laser powder bed fusion (LPBF) printing forming, wherein the spherical nickel-based superalloy powder with a particle size of 53-120 μm is used for laser direct energy deposition printing forming, and the spherical nickel-based superalloy powder with a particle size of 10-53 μm is used for laser powder bed fusion printing forming.

[0029] As an embodiment of the present application, the conditions of the laser direct energy deposition printing forming include that the laser power can be 1800-2200 W, specifically 1800 W, 1900 W, 2000 W, 2100 W or 2200 W; the laser scanning speed can be 600-960 mm / s, specifically 600 mm / s, 650 mm / s, 700 mm / s, 750 mm / s, 800 mm / s, 850 mm / s or 960 mm / s; the powder feeding amount can be 1-2 r / min, specifically 1 r / min, 1.2 r / min, 1.5 r / min, 1.8 r / min or 2 r / min; the overlap width can be 1-2 mm, specifically 1 mm, 1.2 mm, 1.5 mm, 1.8 mm or 2 mm; and the layer thickness can be 0.5-1.5 mm, specifically 0.5 mm, 0.8 mm, 1 mm, 1.2 mm or 1.5 mm. The printed alloy prepared by the laser direct energy deposition printing forming method of the present application has no cracks inside, high density, no or only a small amount of un-melted areas, exhibits excellent printing performance, and the porosity is ≤0.07%, further ≤0.06%.

[0030] As an embodiment of the present application, the conditions of the laser powder bed fusion printing forming include: the laser power can be 215-335 W, specifically 215 W, 235 W, 265 W, 295 W or 335 W; the laser scanning speed can be 800-1100 mm / s, specifically 800 mm / s, 850 mm / s, 900 mm / s, 950 mm / s, 1000 mm / s, 1050 mm / s or 1100 mm / s; the scanning interval can be 0.1-0.3 mm, specifically 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm or 0.3 mm; the powder layer thickness can be 0.02-0.06 mm, specifically 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm or 0.06 mm. The printing state alloy prepared by the laser powder bed fusion printing forming method of the present application has almost no defects in the interior, high density, and excellent printing performance, and the porosity is ≤0.04%.

[0031] As an embodiment of the present application, the laser direct energy deposition printing forming or the laser powder bed fusion printing forming is preferably carried out under the condition that the oxygen content is less than 10 ppm and the water content is less than 50 ppm; the laser direct energy deposition printing forming or the laser powder bed fusion printing forming is preferably carried out in a protective atmosphere, and the protective atmosphere can be argon, and the purity of the argon can be ≥99.99%. As an embodiment of the present application, in the process of the laser direct energy deposition printing forming or the laser powder bed fusion printing forming, the laser scanning direction is rotated by 67° after printing each layer. In the process of the laser direct energy deposition printing forming or the laser powder bed fusion printing forming of the present application, a 67° rotating scanning path is used for each layer, and the laser head starts scanning from the farthest end after the end of each layer, that is, the starting point of each layer is set according to the "maximum span principle" to disperse thermal stress.

[0032] As an embodiment of the present application, the printing raw material can further comprise Y2O3 nanoparticles, that is, the printing raw material is spherical nickel-based superalloy powder and Y2O3 nanoparticles; when the printing raw material further comprises Y2O3 nanoparticles, the laser additive manufacturing method is specifically laser direct energy deposition printing forming. As an embodiment of the present application, the particle size of the Y2O3 nanoparticles can be 50-200 nm, and further can be 50-150 nm, and in the embodiment, Y2O3 nanoparticles with an average particle size of 100 nm are specifically used; the mass content of Y2O3 nanoparticles in the printing raw material is ≤1%, and further can be 0.5-1%, and specifically can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%. The present application introduces Y2O3 nanoparticles into high cobalt and γ' content nickel-based superalloy, which can hinder dislocation movement and grain boundary migration, and is beneficial to improve the oxidation resistance and high temperature strength of the alloy.

[0033] As an embodiment of the present application, when the printing raw material is spherical nickel-based superalloy powder and Y2O3 nanoparticles, the preparation method of the printing raw material comprises the following steps: mixing the spherical nickel-based superalloy powder and Y2O3 nanoparticles by using an acoustic resonance mixer to obtain the printing raw material; the mixing frequency can be 5-15 times, and specifically can be 10 times; the mixing time of each time can be 2 min, that is, the total effective mixing time is 10-30 min; and the acceleration of each mixing can be independently 65-85 g, and specifically can be 75 g. In the embodiment of the present application, the spherical nickel-based superalloy powder and Y2O3 nanoparticles are placed in the mixing tank of the acoustic resonance mixer for mixing, the mixing tank is taken out for cooling after each mixing is completed, and the next mixing is continued after the powder is cooled to room temperature, and finally the uniformly mixed printing raw material is obtained. In the embodiment of the present application, the acoustic resonance mixer is used for mixing, through the joint action of macroscopic mixing flow, microscopic strong mixing flow and longitudinal acoustic wave, the nano-sized Y2O3 particles are uniformly attached to the surface of the micron-sized spherical nickel-based superalloy powder, and the sphericity of the powder is not damaged, the problem of dispersion of Y2O3 nanoparticles in laser additive manufacturing is solved, the Y2O3 nanoparticles are uniformly and dispersedly distributed in the nickel-based superalloy, the obtained alloy has excellent high temperature mechanical properties, and is suitable for directly forming turbine blades or additive manufacturing repair of damaged blades. If the ball milling method is used, on the one hand, the sphericity of the powder is damaged, the flowability of the powder is reduced, and the pore density of the sample in the additive manufacturing process is increased; on the other hand, the Y2O3 nanoparticles are easy to agglomerate due to high surface tension, thereby causing uneven mixing, and harmful elements such as oxygen and nitrogen are inevitably introduced in the ball milling process, which is easy to produce cracks and unmelted areas in the subsequent laser additive manufacturing process.

[0034] As an embodiment of the present application, when the printing raw material further comprises Y2O3 nanoparticles, the optional condition of the laser direct energy deposition printing forming is preferably consistent with the above technical solution, which will not be repeated here. In the present application, when the printing raw material further comprises Y2O3 nanoparticles, the printing state alloy prepared by using the laser direct energy deposition printing forming method has no internal cracks, only a small amount of un-melted area, exhibits excellent printing performance, and the porosity is ≤0.09%, further ≤0.06%. In the present application, when the printing raw material further comprises Y2O3 nanoparticles, it is not suitable to use the laser powder bed melting printing forming method, because the temperature of the molten pool in the laser powder bed melting printing forming process is extremely high, which can cause part of the Y2O3 nanoparticles to be thermally decomposed into active Y atoms and O atoms, and the decomposed O atoms are segregated to high-angle grain boundaries in the rapid solidification process. The enrichment of O atoms at the grain boundaries significantly reduces the grain boundary binding energy, inducing grain boundary embrittlement; in addition, the extremely high cooling rate of the laser powder bed melting printing forming causes the molten pool to rapidly solidify, producing huge thermal stress, thereby causing a large number of defects in the nickel-based high-temperature alloy during the laser powder bed melting printing forming process after adding Y2O3 nanoparticles.

[0035] After obtaining the printing state alloy, the printing state alloy is heat treated to obtain the high cobalt and gamma prime content nickel-based superalloy. As an embodiment of the present application, the heat treatment can include solution-aging treatment or hot isostatic pressing treatment. As an embodiment of the present application, the solution-aging treatment includes solution treatment and aging treatment in sequence. As an embodiment of the present application, the solution treatment includes that the temperature can be 1150-1250 DEG C, and specifically can be 1150 DEG C, 1180 DEG C, 1200 DEG C, 1220 DEG C or 1250 DEG C; the holding time can be 1-3 h, and specifically can be 1 h, 1.5 h, 2.0 h, 2.5 h or 3.0 h; and after the holding time ends, air cooling is preferably further included. As an embodiment of the present application, the aging treatment includes that the temperature can be 950-1050 DEG C, and specifically can be 950 DEG C, 980 DEG C, 1000 DEG C, 1020 DEG C or 1050 DEG C; the holding time can be 45-55 h, and specifically can be 45 h, 47 h, 49 h, 51 h or 55 h; and after the holding time ends, air cooling is preferably further included. As an embodiment of the present application, the isostatic pressing treatment includes that the temperature can be 1150-1250 DEG C, and specifically can be 1150 DEG C, 1180 DEG C, 1200 DEG C, 1220 DEG C or 1250 DEG C; the pressure can be 110-130 MPa, and specifically can be 110 MPa, 115 MPa, 120 MPa, 125 MPa or 130 MPa; and the holding and pressure maintaining time can be 3-6 h, and specifically can be 3 h, 3.5 h, 4.0 h, 5.0 h or 6.0 h. Through the heat treatment, the present application can close the small amount of un-melted areas in the printing state alloy, improve the alloy density and high temperature mechanical properties.

[0036] The method of the present application can realize crack-free laser additive manufacturing of nickel-based superalloy and excellent high temperature mechanical properties through component design and process control while maintaining high Al+Ti+Ta content and high gamma prime phase fraction.

[0037] The high cobalt and gamma' content nickel-based superalloy prepared by the preparation method has excellent high-temperature mechanical properties, and the yield strength can be 154-437 MPa, further can be 285-306 MPa; the tensile strength can be 162-480 MPa, further can be 315-337 MPa; and the elongation can be 2.3-16.4%, further can be 4.5-8.6% under the condition of 1000 DEG C high temperature.

[0038] The application provides application of the high cobalt and gamma' content nickel-based superalloy in an aero-engine turbine blade. As an embodiment of the application, the aero-engine turbine blade of the high cobalt and gamma' content nickel-based superalloy material can be directly prepared by laser additive manufacturing and heat treatment of the printing raw material; or the printing raw material can be used as a repair material to repair the damaged aero-engine turbine blade by laser additive manufacturing and heat treatment.

[0039] The technical solutions in the application will be described clearly and completely in combination with the embodiments in the application. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments. Based on the embodiments in the application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0040] In the following experiments, the specific process or condition is not specified, and the conventional process or condition is used; the reagent or instrument used is not specified by the manufacturer, and is a conventional product that can be purchased on the market.

[0041] Embodiment 1 The embodiment provides a high cobalt and gamma' content nickel-based superalloy, which comprises the following components in percentage by mass: Cr 8%, Co 30%, W 4%, Mo 4%, Al 6%, Ti 1%, Ta 7%, B 0.015%, C 0.1%, and the balance is Ni; and a preparation method of the high cobalt and gamma' content nickel-based superalloy comprises the following steps. (1) according to the element ratio of the nickel-based superalloy, Ni particles, Co particles, Cr particles, Al particles, Ti particles, Ta bulk, Mo particles, W bulk, graphite particles and B particles (purity > 99.95%) are used as raw materials for batching, and then 5 times of suspension induction melting is carried out, and the obtained melt is cast into a mold at 1450-1500 ℃ to obtain a master alloy ingot with a size of Φ 35 mm*200 mm (impurity element content < 5 ppm); the furnace is vacuumed to 7*10 - 3 Pa, and then argon (purity ≥ 99.99%) is filled to 0.3 MPa, and each suspension induction melting includes: first, heat the raw materials at a power of 100 kW for 10 min, then increase the power to 200 kW to completely melt the raw materials, and finally reduce the power to 150 kW for 10 min; (2) the riser of the master alloy ingot is cut off, and then turned into a master alloy electrode rod with a size of Φ 30 mm*160 mm, and fixed on the feeding platform of the plasma rotating electrode device, and powder is prepared to obtain spherical nickel-based superalloy powder with a particle size of 10-120 μm; the spherical nickel-based superalloy powder is screened to obtain spherical nickel-based superalloy powder with a particle size range of 53-120 μm (coarse powder, yield 50%) and 10-53 μm (fine powder, yield 50%); the atomization chamber is vacuumed to 5*10 -3 Pa, and then argon (purity ≥ 99.99%) is filled, and the working pressure of argon is controlled at 0.04-0.06 MPa; the powder preparation conditions include: main arc current 700 A, maintenance arc current 100 A, master alloy electrode rod rotating speed 15000-20000 r / min, feeding speed 1.2 mm / s, argon (purity ≥ 99.99%) flow rate 10 L / min; (3) the spherical nickel-based superalloy powder with a particle size of 53-120 μm (coarse powder) and 10-53 μm (fine powder) is placed in a vacuum drying box and dried at 120 ℃ for 2 h to obtain dried coarse powder (particle size 53-120 μm) and dried fine powder (particle size 10-53 μm), respectively; The dried coarse powder (particle size 53-120 μm) is loaded into the powder bin of the laser energy deposition (LDED) equipment, the forming bin of the laser energy deposition equipment is subjected to a circulating gas washing operation, and then laser direct energy deposition printing forming is carried out to obtain a size of 100*50*20 mm 3a printed-state nickel-based superalloy block (denoted as LDED printed-state alloy); the laser direct energy deposition printing forming conditions include: a laser power of 2200 W, a scanning speed of 960 mm / s, a powder feeding amount of 1 r / min, and a lap width of 1.4 mm; in order to reduce thermal stress, after the end of each layer printing, the laser head starts scanning from the farthest end, and the scanning direction is rotated by 67° for each layer; during the laser direct energy deposition printing forming, the oxygen content in the printing chamber of the laser energy deposition equipment is <10 ppm and the water content is <50 ppm; The dry fine powder (particle size of 10-53 μm) is loaded into the chamber of a laser powder bed fusion (LPBF) equipment, the chamber is subjected to a circulating gas washing operation, and then laser powder bed fusion printing forming is performed to obtain a printed-state nickel-based superalloy block (denoted as LPBF printed-state alloy) with a size of 100×50×20 mm 3 The laser powder bed fusion printing forming conditions include: a laser power of 275 W, a scanning speed of 1100 mm / s, a scanning interval of 0.1 mm, and a powder layer thickness of 0.04 mm; in order to reduce thermal stress, after the end of each layer printing, the laser head starts scanning from the farthest end, and the scanning direction is rotated by 67° for each layer; during the laser powder bed fusion printing forming, the oxygen content in the printing chamber of the laser powder bed fusion equipment is <10 ppm and the water content is <50 ppm. (4) The LDED printed-state alloy and the LPBF printed-state alloy are independently subjected to solid solution treatment and aging treatment in sequence, respectively, to obtain LDED aged-state alloy and LPBF aged-state alloy, which are target high-cobalt and high-γ' content nickel-based superalloys; the solid solution treatment temperature is 1250 ℃, the holding time is 2 h, and water cooling is performed after the holding; the aging treatment temperature is 1000 ℃, the holding time is 50 h, and water cooling is performed after the holding. Alternatively, the LDED printed-state alloy and the LPBF printed-state alloy are independently subjected to hot isostatic pressing treatment to obtain LDED hot isostatic pressed alloy and LPBF hot isostatic pressed alloy, which are target high-cobalt and high-γ' content nickel-based superalloys; the hot isostatic pressing treatment temperature is 1180 ℃, the pressure is 120 MPa, and the holding and pressure maintaining time is 4 h.

[0042] Figure 1 It is a photomicrograph of the LDED printed-state alloy in Example 1, and the results show that the LDED printed-state alloy has no internal cracks and high density, showing excellent printing performance; the Image J software is used to count the surface defects of the sample, and the results show that the porosity of the sample is 0.06%.

[0043] Figure 2The optical microscope photos of the LPBF printed alloy in Example 1 show that the LPBF printed alloy has almost no defects inside, high density and excellent printing performance; the sample surface defects are counted by using Image J software, and the results show that the porosity of the sample is 0.04%.

[0044] Figure 3 The scanning electron microscope photos of the LDED aged alloy and the LPBF aged alloy in Example 1, wherein (a) is the scanning electron microscope photo of the LDED aged alloy, and (b) is the scanning electron microscope photo of the LPBF aged alloy; the results show that the average size of the γ' phase in the LDED aged alloy is 679 nm, and the volume fraction is about 63%; the average size of the γ' phase in the LPBF aged alloy is 402 nm, and the volume fraction is about 53%.

[0045] Example 2 In this example, Y2O3 nanoparticles are introduced on the basis of Example 1, and laser direct energy deposition is used for printing and forming, so as to finally prepare a Y2O3 nanoparticle reinforced high cobalt and high γ' content nickel-based superalloy. If not otherwise specified, the operation conditions in this example are the same as those in Example 1, which are described in detail as follows.

[0046] The Y2O3 nanoparticle reinforced high cobalt and high γ' content nickel-based superalloy comprises the following components in mass percentage: Cr 8%, Co 30%, W 4%, Mo 4%, Al 6%, Ti 1%, Ta 7%, B 0.015%, C 0.1%, Y2O3 1%, and the balance is Ni. (1) According to the element ratio of the nickel-based superalloy, Ni particles, Co particles, Cr particles, Al particles, Ti particles, Ta bulk, Mo particles, W bulk, graphite particles and B particles (all with a purity of > 99.95%) are used as raw materials for batching, and then the operation in step (1) of Example 1 is performed to obtain a master alloy ingot; (2) The operation in step (2) of Example 1 is performed to prepare and screen the spherical nickel-based superalloy powder with a particle size range of 53-120 μm by using the master alloy ingot; (3) The spherical nickel-based superalloy powder and Y2O3 nanoparticles (with an average particle size of 100 nm) are placed in the powder mixing tank of the acoustic resonance mixer for powder mixing to obtain the spherical nickel-based superalloy powder containing Y2O3 nanoparticles; the acceleration of the powder mixing is 75 g, the number of powder mixing is 5 times, the time of each powder mixing is 2 min (i.e. the total running time of the powder mixing is 10 min), and after each powder mixing is completed, the powder mixing tank is taken out for cooling, and after the powder is cooled to room temperature, the next powder mixing is continued. (4) The Y2O3 nanoparticle-containing spherical nickel-based superalloy powder was placed in a vacuum drying oven and dried at 120 °C for 2 h, and then the obtained dried powder was subjected to laser direct energy deposition printing according to the operation of step (3) of Example 1, to obtain a printed nickel-based superalloy block with a size of 100 x 50 x 20 mm (denoted as LDED printed alloy); 3 (5) The LDED printed alloy was sequentially subjected to solution treatment and aging treatment according to the operation of step (4) of Example 1, to obtain an LDED aged alloy, which is the target Y2O3 nanoparticle-reinforced high-cobalt and high-γ' nickel-based superalloy; Alternatively, the LDED printed alloy was subjected to hot isostatic pressing according to the operation of step (4) of Example 1, to obtain an LDED hot isostatic pressed alloy, which is the target Y2O3 nanoparticle-reinforced high-cobalt and high-γ' nickel-based superalloy.

[0047] Figure 4 FIG. 2 is a scanning electron microscope image and an element distribution diagram of the Y2O3 nanoparticle-containing spherical nickel-based superalloy powder in Example 2, wherein (a), (b), and (c) are scanning electron microscope images, and (d) is an element distribution diagram. As can be seen from (a) and (b) in FIG. 2, the powder has good sphericity; as can be seen from (c) and (d) in FIG. 2, the Y2O3 nanoparticles are uniformly coated on the spherical nickel-based superalloy powder, and the sphericity of the alloy powder is not damaged after mixing the powder by using an acoustic resonance mixer. Figure 4 Figure 4

[0048] Figure 5 FIG. 5 is an optical microscope image of the LDED printed alloy in Example 2, and the results show that the LDED printed alloy has no cracks inside and only a small amount of un-melted areas, showing excellent printing performance; the surface defects of the sample were counted by using Image J software, and the results show that the porosity of the sample is 0.06%.

[0049] Figure 6 FIG. 6 is a scanning electron microscope image of the LDED aged alloy in Example 2, and the results show that the average size of the γ' phase in the LDED aged alloy is 663 nm, and the volume fraction is about 70%.

[0050] Figure 7 FIG. 7 is an optical microscope image of the LDED hot isostatic pressed alloy in Example 2, and the results show that the LDED hot isostatic pressed alloy has no cracks, and a small amount of un-melted areas are closed under high temperature and high pressure conditions, and the sample has high density.

[0051] Example 3 ​​​The embodiment introduces Nb and adjusts the content of each element on the basis of embodiment 1, and finally prepares a high cobalt and γ' content nickel-based superalloy. If there is no special instruction, the related operation conditions in this embodiment are the same as those in embodiment 1, which are described in detail below.

[0052] The embodiment provides a high cobalt and γ' content nickel-based superalloy, which comprises the following components in mass percentage: Cr 9%, Co 20%, W 7%, Mo 1%, Al 4%, Ti 0.5%, Ta 5.5%, Nb 3.5%, B 0.005%, C 0.05%, and the balance of Ni; and the preparation method of the high cobalt and γ' content nickel-based superalloy comprises the following steps: (1) According to the element ratio of the nickel-based superalloy, Ni particles, Co particles, Cr particles, Al particles, Ti particles, Ta blocks, Mo particles, W blocks, Nb blocks, graphite particles and B particles (all with a purity of > 99.95%) are used as raw materials for batching, and then the operation of step (1) of embodiment 1 is performed to obtain a master alloy ingot; (2) According to the operation of step (2) of embodiment 1, the master alloy ingot is used to prepare spherical nickel-based superalloy powder with particle sizes of 53-120 μm (coarse powder) and 10-53 μm (fine powder); (3) According to the operation of step (3) of embodiment 1, the spherical nickel-based superalloy powder with particle sizes of 53-120 μm (coarse powder) and 10-53 μm (fine powder) is used to prepare LDED printing state alloy and LPBF printing state alloy, respectively; (4) According to the operation of step (4) of embodiment 1, the LDED printing state alloy and the LPBF printing state alloy are used to prepare LDED aging state alloy and LPBF aging state alloy, respectively, after solid solution treatment and aging treatment; Alternatively, according to the operation of step (4) of embodiment 1, the LDED printing state alloy and the LPBF printing state alloy are used to prepare LDED hot isostatic pressing state alloy and LPBF hot isostatic pressing state alloy, respectively, after hot isostatic pressing treatment.

[0053] Figure 8 It is the optical microscope photo of the LDED printing state alloy in embodiment 3, and the results show that the LDED printing state alloy has no cracks inside and high density, showing excellent printing performance; the Image J software is used to count the surface defects of the sample, and the results show that the porosity of the sample is 0.07%.

[0054] Figure 9The optical microscope photos of the LPBF printed alloy in Example 3 show that the LPBF printed alloy has almost no defects inside, high density, and excellent printing performance; the Image J software is used to count the surface defects of the sample, and the results show that the porosity of the sample is 0.04%.

[0055] Figure 10 The scanning electron microscope photos of the LDED aged alloy and the LPBF aged alloy in Example 3, wherein (a) is the scanning electron microscope photo of the LDED aged alloy, and (b) is the scanning electron microscope photo of the LPBF aged alloy; the results show that the average size of the γ' phase in the LDED aged alloy is 384 nm, and the volume fraction is about 44%; the average size of the γ' phase in the LPBF aged alloy is 305 nm, and the volume fraction is about 61%.

[0056] Example 4 This example introduces Y2O3 nanoparticles and Nb on the basis of Example 1 and adjusts the content of each element, and finally prepares a Y2O3 nanoparticle reinforced high cobalt and high γ' content nickel-based superalloy. If not otherwise specified, the operation conditions in this example are the same as those in Example 1, which are described in detail as follows.

[0057] This example provides a Y2O3 nanoparticle reinforced high cobalt and high γ' content nickel-based superalloy, which comprises the following components in mass percentage: Cr 9%, Co 20%, W 7%, Mo 1%, Al 4%, Ti 0.5%, Ta 5.5%, Nb 3.5%, B 0.005%, C 0.05%, Y2O3 0.5%, and the balance of Ni; the preparation method of the Y2O3 nanoparticle reinforced high cobalt and high γ' content nickel-based superalloy comprises the following steps: (1) According to the element ratio of the nickel-based superalloy, Ni particles, Co particles, Cr particles, Al particles, Ti particles, Ta blocks, Mo particles, W blocks, Nb blocks, graphite particles and B particles (all with a purity of > 99.95%) are used as raw materials for batching, and then the operation of step (1) in Example 1 is performed to obtain a master alloy ingot; (2) The operation of step (2) in Example 2 is performed to prepare and screen the spherical nickel-based superalloy powder with a particle size range of 53-120 μm using the master alloy ingot; (3) Put the spherical nickel-based superalloy powder and Y2O3 nanoparticles (particle size of 100 nm) into the powder mixing tank of the acoustic resonance mixer for powder mixing to obtain the spherical nickel-based superalloy powder containing Y2O3 nanoparticles; the acceleration of the powder mixing is 75 g, the number of powder mixing is 5 times, the time of each powder mixing is 2 min (i.e. the total running time of powder mixing is 10 min), the powder mixing tank is taken out for cooling after each powder mixing, and the next powder mixing is continued after the powder is cooled to room temperature; (4) Put the spherical nickel-based superalloy powder containing Y2O3 nanoparticles into a vacuum drying oven, dry at 120 ℃ for 2 h, and then according to the operation of step (3) of Example 1, the obtained dry powder is subjected to laser direct energy deposition printing to obtain a printed nickel-based superalloy block with a size of 100x50x20 mm 3 (Recorded as LDED printed alloy); (5) According to the operation of step (4) of Example 1, the LDED printed alloy is sequentially subjected to solution treatment and aging treatment to obtain an LDED aged alloy, which is the target Y2O3 nanoparticle reinforced high cobalt and high γ' content nickel-based superalloy. Alternatively, according to the operation of step (4) of Example 1, the LDED printed alloy is subjected to hot isostatic pressing to obtain an LDED hot isostatic pressed alloy, which is the target Y2O3 nanoparticle reinforced high cobalt and high γ' content nickel-based superalloy.

[0058] Figure 11 The optical microscope image of the LDED printed alloy in Example 4 shows that the LDED printed alloy has no cracks in the interior and a small amount of un-melted areas, showing excellent printing performance; the Image J software is used to count the surface defects of the sample, and the results show that the porosity of the sample is 0.09%.

[0059] Figure 12 The scanning electron microscope image of the LDED aged alloy in Example 4 shows that the average size of the γ' phase in the LDED aged alloy is 482 nm, and the volume fraction is about 58%.

[0060] Comparative Example 1 In this example, Y2O3 nanoparticles are introduced based on Example 1, and laser powder bed fusion printing is used for forming, and finally a Y2O3 nanoparticle reinforced high cobalt and high γ' content nickel-based superalloy is prepared. If not otherwise specified, the operation conditions in this example are the same as those in Example 1, which are described in detail as follows.

[0061] The comparative example 1 provides a Y2O3 nanoparticle reinforced high cobalt and γ' content nickel-based superalloy, which comprises the following components in mass percentage: Cr 8%, Co 30%, W 4%, Mo 4%, Al 6%, Ti 1%, Ta 7%, B 0.015%, C 0.1%, Y2O3 1%, and the balance of Ni; the preparation method of the Y2O3 nanoparticle reinforced high cobalt and γ' content nickel-based superalloy comprises the following steps: (1) according to the element ratio of the nickel-based superalloy, the raw materials of Ni particles, Co particles, Cr particles, Al particles, Ti particles, Ta bulk, Mo particles, W bulk, graphite particles and B particles (purity > 99.95%) are used for batching, and then the operation of step (1) of example 1 is carried out to obtain a master alloy ingot; (2) according to the operation of step (2) of example 1, the master alloy ingot is used to prepare and sieve to obtain spherical nickel-based superalloy powder with a particle size range of 10-53 μm; (3) the spherical nickel-based superalloy powder and Y2O3 nanoparticles (particle size 100 nm) are placed in a powder mixing tank, and the powder is mixed by using an acoustic resonance mixer to obtain spherical nickel-based superalloy powder containing Y2O3 nanoparticles; the acceleration of the powder mixing is 75 g, the number of powder mixing is 5 times, the time of each powder mixing is 2 min (i.e. the total running time of powder mixing is 10 min), after each powder mixing, the powder mixing tank is taken out for cooling, and after the powder is cooled to room temperature, the next powder mixing is carried out; (4) the spherical nickel-based superalloy powder containing Y2O3 nanoparticles is placed in a vacuum drying box and dried at 120 ℃ for 2 h, and then the dried powder is subjected to laser powder bed fusion printing according to the operation of step (3) of example 1 to obtain a printed nickel-based superalloy block with a size of 100×50×20 mm 3 , which is recorded as LPBF printed alloy, which is the target Y2O3 nanoparticle reinforced high cobalt and γ' content nickel-based superalloy.

[0062] Figure 13 The optical microscope image of the LPBF printed alloy in comparative example 1 shows that there are a small amount of pores and a large number of cracks on the surface of the sample, which is because the temperature of the molten pool in the LPBF process is extremely high, which causes part of the Y2O3 nanoparticles to decompose into active Y atoms and O atoms, and the decomposed O atoms are segregated to high-angle grain boundaries during rapid solidification, which significantly reduces the grain boundary bonding energy and induces grain boundary embrittlement; in addition, the extremely high cooling rate of LPBF causes rapid solidification of the molten pool, resulting in a large amount of defects in the nickel-based superalloy during the LPBF process after adding Y2O3 nanoparticles; the sample surface defects are counted by using ImageJ software, and the results show that the crack density of the sample is 3.84 mm / mm2 .

[0063] Test Example 1 The nickel-based superalloys prepared in Examples 1-4 were made into dog-bone shaped plate-shaped tensile samples, and high-temperature tensile property tests were performed at 1000℃, with the LDED printed-state alloy prepared in Example 2 as a comparison, and the specific test results are shown in Table 1. As can be seen from Table 1, compared with the samples without adding Y2O3 nanoparticles in Examples 1 and 3, the mechanical properties of the nickel-based superalloy prepared in Example 2 are significantly improved, and thus it can be seen that adding Y2O3 nanoparticles can effectively improve the high-temperature mechanical properties of the nickel-based superalloy. Under the condition of 1000℃ high temperature, the yield strength of the nickel-based superalloy after hot isostatic pressing in Example 2 can reach 285 MPa, the tensile strength can reach 337 MPa, and the elongation can reach 16.4%, and the comprehensive high-temperature mechanical properties are the best, and have high application potential.

[0064] Table 1 Performance test results of nickel-based superalloys in Examples 1-4 and LDED printed-state alloy in Example 2

[0065] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for preparing a nickel-based superalloy with high cobalt and γ' content, comprising the following steps: The spherical nickel-based superalloy powder is provided, and the composition of the spherical nickel-based superalloy powder by mass content includes: Co: 20~30%, Cr: 8~10%, Al+Ti: 4~7%, W+Mo+Ta: 14~16%, Nb: 0~3.5%, B: 0.001~0.015%, C: 0.05~0.1%, and the balance is Ni; Using the spherical nickel-based superalloy powder as the printing material, laser additive manufacturing is performed to obtain a printed alloy; the laser additive manufacturing method includes laser direct energy deposition printing or laser powder bed fusion printing. The printed alloy is heat-treated to obtain the high cobalt and γ' content nickel-based superalloy.

2. The preparation method according to claim 1, characterized in that, The spherical nickel-based superalloy powder contains 4-6% Al by mass, 0.5-2% Ti by mass, 4-7% W by mass, 1-4% Mo by mass, and 5-8% Ta by mass.

3. The preparation method according to claim 1, characterized in that, The printing material further includes Y2O3 nanoparticles; when the printing material further includes Y2O3 nanoparticles, the preparation method of the printing material includes: mixing the spherical nickel-based high-temperature alloy powder with Y2O3 nanoparticles using an acoustic resonance mixer to obtain the printing material; When the printing material also includes Y2O3 nanoparticles, the laser additive manufacturing method is laser direct energy deposition printing.

4. The preparation method according to claim 3, characterized in that, The Y2O3 nanoparticles have a particle size of 50~200nm, and the mass content of Y2O3 nanoparticles in the printing material is ≤1%.

5. The preparation method according to any one of claims 1 to 3, characterized in that, The conditions for laser direct energy deposition printing include: laser power of 1800~2200 W, laser scanning speed of 600~960 mm / s, powder feed rate of 1~2 r / min, overlap width of 1~2 mm, and layer thickness of 0.5~1.5 mm.

6. The preparation method according to claim 1 or 2, characterized in that, The conditions for laser powder bed fusion printing include: laser power of 215~335 W, laser scanning speed of 800~1100 mm / s, scanning spacing of 0.1~0.3 mm, and powder layer thickness of 0.02~0.06 mm.

7. The preparation method according to claim 1, characterized in that, The heat treatment includes solution-aging treatment or hot isostatic pressing treatment.

8. The preparation method according to claim 7, characterized in that, The solution-aging treatment includes sequential solution treatment and aging treatment; the conditions for solution treatment include: temperature of 1150~1250 ℃, holding time of 1~3 h, and air cooling after holding; the conditions for aging treatment include: temperature of 950~1050 ℃, holding time of 45~55 h, and air cooling after holding. The conditions for the isostatic pressing treatment include: a temperature of 1150~1250 ℃, a pressure of 110~130 MPa, and a holding time of 3~6 h.

9. The nickel-based superalloy with high cobalt and γ' content prepared by the preparation method according to any one of claims 1 to 8 has a γ' phase volume fraction ≥ 44%.

10. The application of the high cobalt and γ' content nickel-based superalloy of claim 9 in aero-engine turbine blades.

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