Nickel-based superalloy resistant to neutron irradiation and high temperature and used for nuclear fusion reactor and preparation method of nickel-based superalloy

Abstract

The invention provides a neutron-irradiation-resistant and high-temperature-resistant nickel-based superalloy for a nuclear fusion reactor and a preparation method of the nickel-based superalloy, and belongs to the technical field of nuclear fusion materials. According to the invention, alloy formula design and process technology optimization measures are provided from the angles of grain boundary strengthening, grain refinement, multi-stage aging heat treatment optimization, solid solution cooling rate control, surface coating, surface oxidation and passivation and the like; and the produced cladding material for the nuclear fusion device has higher high-temperature strength, high neutron radiation resistance, better thermal shock resistance and longer service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nuclear fusion materials, in particular to a nickel-based superalloy for nuclear fusion reactors and a preparation method thereof. BACKGROUND

[0002] Controllable nuclear fusion is a technology of releasing energy by artificially controlling light atomic nuclei fusion, mainly using hydrogen isotopes deuterium (D) and tritium (T) to generate helium nuclei (He) and release neutrons and energy.

[0003] The reaction conditions should meet:

[0004] 1) High temperature: temperature > 1 billion ℃, ionizing fuel into plasma to overcome the repulsive force between atomic nuclei.

[0005] 2) High density: plasma density needs to be > 10 20 / m 3 .

[0006] 3) Long time constraint: meet the Lawson criterion (n·τ·T>3×10keV·s / m 3 ) to maintain energy gain.

[0007] The key equipment of controllable nuclear fusion device includes toroidal vacuum chamber and superconducting magnet, which confines the plasma of 100 million degrees by strong magnetic field.

[0008] China EAST device has realized 1.6 billion ℃ plasma stable operation. The demonstration reactor (such as CFETR) is expected to operate in 2035, and commercialization is expected before 2050.

[0009] Currently, there are problems in the shielding cladding materials and vacuum chamber materials of nuclear fusion devices:

[0010] 1) Insufficient radiation resistance

[0011] After irradiation of high-energy neutrons (14.1 MeV), the grain boundary precipitated phase coarsens, resulting in a decrease of more than 40% in 600℃ fracture toughness.

[0012] When irradiated for 100 days, the elongation decays to less than 35% of the initial value.

[0013] Helium bubbles gather at the grain boundary to cause swelling, with an annual swelling rate > 3% / year under the working condition of the fusion reactor.

[0014] 2) Insufficient high-temperature stability

[0015] After long-term operation (> 1000 hours), the attenuation rate of tensile strength at 900℃ is 28%, and the attenuation rate of yield strength is > 32%, affecting the structural stability of the first wall.

[0016] 3) Insufficient thermal fatigue life

[0017] In the thermal cycle condition of 600-900℃ (simulating the transient thermal load of plasma), the crack initiation cycle is only 800-1200 times, which cannot meet the requirement of 5-year design life of fusion reactor.

[0018] 4) Weak thermal shock resistance

[0019] Facing ELMs event (10MW / m 2 Instantaneous heat flux), the surface local melting depth is >150μm, inducing micro-cracks and accelerating erosion. SUMMARY

[0020] The purpose of the present application is to propose alloy formula design and process optimization measures from the aspects of strengthening grain boundary, refining grain, multi-stage aging heat treatment optimization, solid solution cooling rate control, surface coating, surface oxidation passivation, etc., so that the produced nuclear fusion device cladding material has higher high-temperature strength, higher neutron radiation resistance, better thermal shock resistance and longer service life.

[0021] The problems to be solved by the present application include:

[0022] (1) Alloy formula design to obtain obvious grain boundary strengthening effect and grain refinement effect.

[0023] (2) Two-stage aging heat treatment process design and implementation.

[0024] (3) Surface oxidation passivation process design and implementation.

[0025] (4) Surface coating process design and implementation.

[0026] In order to achieve the above purpose, the present application adopts the following technical scheme: a nickel-based superalloy for nuclear fusion reactor with resistance to neutron irradiation and high temperature, comprising the following components by weight percentage:

[0027] C: ≤0.09%,

[0028] Si: ≤1.1%,

[0029] Mn: ≤1.1%,

[0030] S ≤0.01%,

[0031] P ≤0.015%,

[0032] Cr: 13.5-17.5%,

[0033] Al: 0.3-1.1%,

[0034] Ti: 2.15-2.85%,

[0035] B: 0.001-0.03%,

[0036] Nb: 0.8-1.3%,

[0037] Zr: 0.001-0.1%,

[0038] Fe: 4-10%,

[0039] Ni: ≥ 65%,

[0040] The alloy has a tensile strength of ≥1100 MPa at 1000° C. after solution treatment and two-stage aging treatment, and an elongation retention rate of ≥60% after neutron irradiation.

[0041] Preferably, the microstructure of the alloy comprises:

[0042] γ matrix phase,

[0043] γ' strengthening phase (Ni3Al / Ni3Ti), with an average size of 10-100nm,

[0044] Grain boundary purification phase (ZrB2), with an average size of 20-50 nm.

[0045] Further preferably, the alloy surface is provided with a protective coating, and the protective coating comprises:

[0046] Inner layer: 20-50μm vapor-phase aluminized layer,

[0047] Outer layer: 100-150μm CoCrAlY coating.

[0048] To achieve the purpose of the present invention, another technical solution is provided: a method for preparing a neutron irradiation-resistant and high-temperature resistant nickel-based superalloy for a nuclear fusion reactor, comprising the following steps:

[0049] (1) Raw material smelting: the raw materials are prepared according to the above-mentioned composition ratio and smelted by vacuum induction melting + electroslag remelting dual process;

[0050] (2) Hot working: hot forging at 1100-1200℃ for 1-7 hours;

[0051] (3) Solution treatment: keep at 1100-1180℃ for 1-2 hours and then quench with water;

[0052] (4) Two-level aging treatment:

[0053] First stage aging: 825-865℃ for 4-8 hours, air cooling;

[0054] Second stage aging: 675-735℃ for 18-26 hours, air cooling;

[0055] (5) surface treatment:

[0056] The component is loaded into a heating furnace, heated to 800 DEG C, and pre-oxidized in an air environment for 2 hours to promote the formation of a dense Cr2O3 protective film;

[0057] First, a vapor phase aluminizing treatment is performed to form an aluminized layer of 20-50 microns;

[0058] Then, a plasma sprayed CoCrAlY coating is applied, with a thickness of 100-150 microns.

[0059] Preferably, in the two-stage aging treatment:

[0060] The first stage aging is preferably at 850±5 DEG C for 6 hours;

[0061] The second stage aging is preferably at 720±5 DEG C for 20 hours.

[0062] Preferably, the vapor phase aluminizing treatment is performed at an aluminizing temperature of 820-880 DEG C for 4-12 hours.

[0063] Further preferably, the CoCrAlY coating has a difference in thermal expansion coefficient with the GH4145 base material of Delta alpha < 1x10-6 / DEG C, and after the coating is applied, vacuum diffusion annealing is performed at a temperature of 960-1000 DEG C for 1-3 hours.

[0064] The application also provides a nuclear fusion device vacuum chamber component made of the above nickel-based superalloy, which has a service life of > 6 years in a 14.1 MeV neutron irradiation environment and a reduction of 90% in tritium permeation rate.

[0065] The application also provides a nuclear fusion device shielding blanket structure, comprising:

[0066] Base material: the above nickel-based superalloy,

[0067] Cooling channel: liquid metal coolant,

[0068] Wherein, the structure has a thermal shock cycle number of > 1000 times at a working temperature of 1000 DEG C.

[0069] Compared with the prior art, the application achieves the following technical effects:

[0070] Compared with the previous generation of alloys, the nickel-based superalloy of the application has a significantly refined grain of 12 microns, a significantly improved tensile strength at 1000 DEG C of 1160 MPa, a significantly improved high-temperature fatigue life at 600 DEG C of up to 80000 cycles, and a significantly reduced tritium permeation rate of 4.6x10 13atoms / (m2·s), the reduction rate is 90%, and the high-temperature service life can reach 6 years. BRIEF DESCRIPTION OF DRAWINGS

[0071] For ease of illustration, the present application is described in detail by the following specific embodiments and drawings.

[0072] Figure 1 The forging heating process chart of the nickel-based superalloy for the anti-neutron irradiation and high-temperature-resistant nuclear fusion reactor of the present application;

[0073] Figure 2 The heat treatment process chart of the nickel-based superalloy for the anti-neutron irradiation and high-temperature-resistant nuclear fusion reactor of the present application;

[0074] Figure 3 The solid solution heat treatment process curve chart of the nickel-based superalloy for the anti-neutron irradiation and high-temperature-resistant nuclear fusion reactor of the present application. DETAILED DESCRIPTION

[0075] The following is a specific embodiment of the present application and further describes the technical solutions of the present application in combination with the drawings, but the present application is not limited to these embodiments; in the following description, specific details such as specific configurations are provided only to help a comprehensive understanding of the embodiments of the present application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application.

[0076] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0077] The materials, practices and experimental equipment involved in the embodiments of the present application, if not specifically stated, are consistent with the commercially available products in the relevant chemical and biotechnology fields.

[0078] 1. Alloy formula design

[0079] Al and Ti are added to the alloy to form more content of γ'(Ni3Al, Ni3Ti) with nickel. Because γ' is coherent with the austenite matrix, it can hinder dislocation movement, delay crack initiation and propagation, and improve the creep performance of the alloy.

[0080] Grain boundary strengthening: Zr is added to form stable compounds with impurity elements (such as S, O), purify the grain boundary, reduce the precipitation of weak phases, and improve the grain boundary strength. B is added, B is segregated at the grain boundary, reduces the grain boundary energy, reduces the grain boundary cavity and crack nucleation, enhances the grain boundary bonding force, so that the alloy is not easy to break along the grain boundary under high temperature stress.

[0081] Add Zr, B, Nb, Al, Ti, etc. to form carbide, carbonitride and nitride on the grain boundary, inhibit grain boundary sliding, reduce crack propagation rate, improve alloy fatigue performance and improve alloy endurance performance.

[0082] Inhibit the precipitation of harmful phases: B and Zr cooperatively inhibit the precipitation of brittle phases such as η phase (Ni□Ti), σ phase and G phase at the grain boundary, avoid the fragmentation of the matrix continuity, and maintain the uniformity and stability of the structure at high temperature.

[0083] Enhance the anti-creep performance: add Zr, which promotes the transformation of carbide from chain to block, and the block carbide can effectively pin the grain boundary, hinder the grain boundary sliding and diffusion during high temperature creep. Add B, which can slow down the grain boundary diffusion rate, reduce the deformation rate in the third stage of creep, and prolong the creep fracture life.

[0084] Grain boundary oxidation strengthening: B enhances the grain boundary bonding force, reduces the expansion of oxidation cracks along the grain boundary, and at the same time promotes the continuity of Cr2O3 protective film in the grain boundary area, improving the overall oxidation resistance. The purification effect of Zr reduces the impurity concentration at the grain boundary, reduces the defects of the oxidation film (such as holes and cracks), and improves the density and adhesion of the oxidation film.

[0085] Therefore, the alloy system of the present application is designed as follows:

[0086] Table 1 Basic composition of superalloy for controllable nuclear fusion device (percentage, %)

[0087]

[0088] 2. Production process route

[0089] The specific production process route of the present application is as follows:

[0090] Raw material preparation → vacuum induction → electroslag remelting → forging → ultrasonic flaw detection → heat treatment → surface treatment → inspection, packaging and storage.

[0091] 2.1 Raw material preparation:

[0092] The main raw materials include: pure iron, Jinchuan nickel, metallic chromium, pure titanium, pure aluminum, niobium strip, B iron, metallic zirconium, silicon calcium powder, aluminum powder, lime, fluorite, Ni-Mg, etc.

[0093] Raw material requirements: The raw materials are low phosphorus and low carbon grade, without oil stains and moisture. The deoxidizers (silicon calcium powder, aluminum powder, lime, fluorite, Ni-Mg) should be dried in a 450-550℃ oven.

[0094] 2.2 Vacuum smelting:

[0095] This process mainly includes charging, melting, refining, pouring and other processes.

[0096] (1)Charging:

[0097] Charging principle: loose on top and tight on bottom to prevent "bridge".

[0098] Before charging large materials, a layer of small and light materials should be laid on the bottom of the furnace.

[0099] High melting point and not easily oxidized furnace charge such as Jinchuan nickel, metal chromium, and niobium strip should be charged in the middle and lower high temperature zone of the crucible.

[0100] Easily oxidized furnace charge such as Ti, Al, and B iron should be added from the charging hopper 2-5 minutes before tapping under the condition of good deoxidation of the metal liquid.

[0101] (2) Melting period:

[0102] After charging is complete, vacuum should be started. When the pressure in the vacuum chamber reaches 0.03 mbar, power heating should be started.

[0103] During the initial melting period, a relatively high vacuum degree and slow melting speed should be maintained.

[0104] Melting time is 120-150 minutes. After melting, take a sample for full analysis.

[0105] (3) Refining period:

[0106] The main tasks of the refining period are: deoxidation, degassing, removal of volatile inclusions, temperature adjustment, and composition adjustment.

[0107] Refining temperature is 1550-1600℃, further increase the vacuum degree to 0.013 mba, and refining time is greater than 35 minutes.

[0108] The number of slag making during the refining period is 5-7 times. Take a sample for full analysis.

[0109] Adjust the alloy composition to the process requirements, add easily oxidized alloys such as Zr, B, Al, Ti, and high-power stirring for 5-7 minutes.

[0110] Add Ni-Mg 4-6 minutes before tapping for further deoxidation and desulfurization. The addition amount of Ni-Mg is controlled at 0.2-0.4% of the steel quantity.

[0111] (4) Pouring:

[0112] High-power stirring for 2-4 minutes before tapping.

[0113] Tapping temperature is controlled at 1550-1580℃.

[0114] Ingot pouring type Φ220.

[0115] 2.3 Electroslag Remelting:

[0116] Electrode size: Φ220

[0117] Electrode finishing: cutting off the shrinkage cavity at the head of the electrode, grinding the surface of the electrode to remove defects such as cold steel, cracks, slag inclusions, etc.

[0118] Electroslag slag system: using low-melting-point four-component slag CaF2: Al2O3: MgO: CaO = 70:20:5:5 with good fluidity.

[0119] Voltage and current system: voltage 60-65V, current 8000-8500A.

[0120] Electroslag ingot finishing: cutting off the shrinkage cavity at the head of the electroslag ingot, cleaning the surface of the electroslag ingot to remove defects such as heavy oxide scale, slag inclusions, etc.

[0121] 2.4 Forging (see Figure 1 ) :

[0122] Forging equipment uses hydraulic air hammer or fast-forging hydraulic press.

[0123] Forging pressure ratio requirement: 4-12.

[0124] Soaking temperature: 1100-1200℃, heating rate ≦120℃ / hour, soaking time: (0.2-0.4)*D (D is the maximum size of the ingot, unit mm) minutes, but not less than 60 minutes, generally not more than 420 minutes.

[0125] Open forging temperature ≧1130-1170℃, final forging temperature ≧950℃.

[0126] According to the material flaw detection grade requirement, when the flaw detection requirement is high grade, 2-3 times of roughening can be added.

[0127] 2.5 Ultrasonic flaw detection:

[0128] Ultrasonic flaw detection is carried out according to GB / T4162-2008 "Ultrasonic Detection Method for Forging Steel Bar", and the acceptance level is required according to the technical conditions.

[0129] 2.6 Heat treatment (see Figure 2 ) :

[0130] First step, solid solution treatment, soaking temperature 1100-1180℃, soaking time 1-2 minutes / mm, but not less than 1 hour, not more than 2 hours.

[0131] Rapid water cooling after heat treatment, cooling speed ≧100℃ / second.

[0132] Solid solution heat treatment process curve is shown in Figure 3 .

[0133] Second step, once aging, heated to 825-865℃, held for 4-8 hours, air cooled, induced M23 C6 carbide diffuses and precipitates more γ' strengthening phase, increases high temperature strength and fatigue strength, and improves neutron irradiation stability.

[0134] Third step, secondary aging, heating to 675-735℃, holding for 18-26 hours, air cooling, stabilizing carbide size, precipitating fine γ', enhancing hydrogen embrittlement resistance and stress relaxation resistance.

[0135] 2.7 Surface treatment

[0136] 2.7.1 Oxidation passivation

[0137] The component is loaded into a heating furnace, heated to 800℃, and pre-oxidized in air environment for 2 hours to promote the formation of dense Cr□O3 protective film.

[0138] 2.7.2 Vapor phase aluminizing

[0139] The temperature is controlled at 820-880℃, the holding time is controlled at 4-12h, and the thickness of the aluminizing layer is controlled at 20-50μm. Ensure that Al□O · continuous film is formed on the surface of the component.

[0140] 2.7.3 Surface coating

[0141] A CoCrAlY coating with a difference in thermal expansion coefficient Δα < 1×10-6 / ℃) from the substrate is used, and the coating thickness is controlled at 100-150μm to prevent thermal cycle cracking.

[0142] After coating, vacuum diffusion annealing is carried out at a temperature of 960-1000℃ for 1-3h.

[0143] In a preferred embodiment, the chemical composition of the nickel-based superalloy for high-temperature neutron-irradiation-resistant nuclear fusion reactors according to the present application is as follows (see Table 2):

[0144] Table 2 Optimization of the chemical composition of the nickel-based superalloy for high-temperature neutron-irradiation-resistant nuclear fusion reactors

[0145]

[0146] Preferably, the optimization scheme of the Zr content of the nickel-based superalloy for high-temperature neutron-irradiation-resistant nuclear fusion reactors according to the present application is as follows (see Table 3)

[0147] Table 3 Optimization scheme of the Zr content of the nickel-based superalloy for high-temperature neutron-irradiation-resistant nuclear fusion reactors according to the present application

[0148]

[0149] Preferably, the optimized solution of the solid solution heat treatment system of the nickel-based superalloy for the anti-neutron irradiation and high-temperature resistant nuclear fusion reactor of the present application (see Table 4)

[0150] Table 4 Optimized solution of the solid solution heat treatment system of the nickel-based superalloy for the anti-neutron irradiation and high-temperature resistant nuclear fusion reactor of the present application

[0151] Scheme name Solution temperature Soaking time, h Note Scheme 1 1100 0.5 Scheme 2 1100 1.0 Scheme 3 1100 1.5 Scheme 4 1100 2.0 Scheme 5 1120 1.0 Scheme 6 1130 1.0 Scheme 7 1140 1.0 Scheme 8 1150 1.0 Preferred Scheme 9 1160 1.0 Scheme 10 1170 1.0 Scheme 11 1180 1.0

[0152] Preferably, the optimized solution of the cooling rate after solid solution of the nickel-based superalloy for the anti-neutron irradiation and high-temperature resistant nuclear fusion reactor of the present application (see Table 5)

[0153] Table 5 Optimized solution of the cooling rate after solid solution of the nickel-based superalloy for the anti-neutron irradiation and high-temperature resistant nuclear fusion reactor of the present application

[0154] Scheme name Cooling method Cooling rate, ℃ / s Note Scheme 1 Sand cooling 0.1–0.5 Scheme 2 Air cooling 0.5-5 Scheme 3 Air cooling 10-50 Scheme 4 Water cooling ＞100 Preferred

[0155] The nickel-based superalloy for the anti-neutron irradiation and high-temperature resistant nuclear fusion reactor of the present application has a significant grain refinement compared to the previous generation alloy. For specific data, see Table 6.

[0156] Table 6 Comparison of grain size of the nickel-based superalloy for the anti-neutron irradiation and high-temperature resistant nuclear fusion reactor of the present application and the previous generation alloy

[0157]

[0158] The nickel-based superalloy for the anti-neutron irradiation and high-temperature resistant nuclear fusion reactor of the present application has a significant improvement in 1000℃ tensile strength compared to the previous generation alloy. For specific data, see Table 7.

[0159] Table 7 Comparison of 1000℃ tensile strength of the nickel-based superalloy for the anti-neutron irradiation and high-temperature resistant nuclear fusion reactor of the present application and the previous generation alloy

[0160]

[0161]

[0162] The nickel-based superalloy for the anti-neutron irradiation and high-temperature resistant nuclear fusion reactor of the present application has a significant improvement in 600℃ high-temperature fatigue life compared to the previous generation alloy. For specific data, see Table 8.

[0163] Table 8 Comparison of 600℃ high-temperature fatigue life of the nickel-based superalloy for the anti-neutron irradiation and high-temperature resistant nuclear fusion reactor of the present application and the previous generation alloy

[0164]

[0165] The nickel-based superalloy for the anti-neutron irradiation and high-temperature resistant nuclear fusion reactor of the present application has a significant reduction in tritium permeation rate compared to the previous generation alloy. For specific data, see Table 9.

[0166] Table 9 Comparison of tritium permeation rate of the nickel-based superalloy for nuclear fusion reactor with neutron irradiation resistance and high temperature resistance of the present application and the previous generation alloy

[0167]

[0168] The nickel-based superalloy for nuclear fusion reactor with neutron irradiation resistance and high temperature resistance of the present application has obvious improvement in neutron irradiation resistance compared with the previous generation alloy. The specific data are shown in Table 10.

[0169] Table 10 Comparison of neutron irradiation resistance of the nickel-based superalloy for nuclear fusion reactor with neutron irradiation resistance and high temperature resistance of the present application and the previous generation alloy

[0170]

[0171] The nickel-based superalloy for nuclear fusion reactor with neutron irradiation resistance and high temperature resistance of the present application has obvious improvement in high temperature service life compared with the previous generation alloy. The specific data are shown in Table 11.

[0172] Table 11 Comparison of high temperature service life of the nickel-based superalloy for nuclear fusion reactor with neutron irradiation resistance and high temperature resistance of the present application and the previous generation alloy

[0173] Alloy category Nickel-based superalloy for nuclear fusion reactor with high-temperature resistance to neutron irradiation Previous generation alloy Improvement range, % High-temperature service life, years 6 years 2 years 200％

[0174] Those skilled in the art to which the present application pertains can make various modifications or supplements to the specific embodiments described or adopt similar ways to replace, but will not deviate from the inventive concept of the present application or exceed the scope defined by the appended claims.

Claims

1. A nickel-based superalloy for nuclear fusion reactors that is resistant to neutron radiation and high temperature, characterized in that: Calculated by weight percentage, it includes the following components: C：≤0.09％， Si: ≤1.1%, Mn: ≤1.1%, S≤0.01％， P≤0.015％， Cr：13.5-17.5％， Al：0.3-1.1％， Ti: 2.15-2.85%, B：0.001-0.03％， Nb: 0.8-1.3%, Zr：0.001-0.1％， Fe: 4-10%, Ni: ≥ 65%, The alloy has a tensile strength of ≥1100 MPa at 1000° C. after solution treatment and two-stage aging treatment, and an elongation retention rate of ≥60% after neutron irradiation.

2. The neutron irradiation-resistant and high-temperature-resistant nickel-based superalloy for nuclear fusion reactor according to claim 1, characterized in that: The microstructure of the alloy includes: γ matrix phase, γ' strengthening phase (Ni3Al / Ni3Ti), with an average size of 10-100nm, Grain boundary purification phase (ZrB2), with an average size of 10-50 nm.

3. The neutron irradiation-resistant and high-temperature-resistant nickel-based superalloy for nuclear fusion reactor according to claim 1 or 2, characterized in that: The alloy surface is provided with a protective coating, and the protective coating comprises: Inner layer: 20-50μm vapor-phase aluminized layer, Outer layer: 100-150μm CoCrAlY coating.

4. A method for preparing the neutron irradiation-resistant and high-temperature-resistant nickel-based superalloy for nuclear fusion reactors according to claim 3, characterized in that: The following steps are involved: (1) Raw material smelting: the raw materials are prepared according to the above-mentioned composition ratio and smelted by vacuum induction melting + electroslag remelting dual process; (2) Hot working: hot forging at 1100-1200℃ for 1-7 hours; (3) Solution treatment: keep at 1100-1180℃ for 1-2 hours and then quench with water; (4) Two-level aging treatment: First stage aging: 825-865℃ for 4-8 hours, air cooling; Second stage aging: 675-735℃ for 18-26 hours, air cooling; (5) Surface treatment: First, perform vapor phase aluminizing treatment to form a 20-50μm aluminized layer; Then plasma spray CoCrAlY coating is applied with a thickness of 100-150 μm.

5. The preparation method according to claim 4, characterized in that The surface treatment step (5) also includes an oxidation passivation step: the component is placed in a heating furnace, heated to 800°C and kept warm, and pre-oxidized in an air environment for 2 hours to promote the formation of a dense Cr□O3 protective film.

6. The preparation method according to claim 5, characterized in that In the two-stage aging treatment: The first stage aging temperature is preferably 850±5℃, and the temperature is kept for 6 hours; The second stage aging is preferably performed at 720±5℃ for 20 hours.

7. The preparation method according to claim 6, characterized in that The vapor phase aluminizing treatment adopts: aluminizing temperature: 820-880° C., aluminizing time: 4-12 hours.

8. The preparation method according to any one of claims 4 to 7, characterized in that The difference in thermal expansion coefficient between the CoCrAlY coating and the substrate is Δα<1×10 -6 / ℃, after coating, vacuum diffusion annealing is carried out at a temperature of 960-1000℃ for 1-3h.

9. A vacuum chamber component of a nuclear fusion device, characterized in that: The component is made of the nickel-based superalloy according to any one of claims 1 to 3, and has a service life of ≥6 years under a 14.1 MeV neutron irradiation environment, and tritium permeability is reduced by 90%.

10. A shielding blanket structure for a nuclear fusion device, characterized in that: include: Matrix material: the nickel-based superalloy according to any one of claims 1 to 3, Cooling channel: built-in liquid metal coolant, The structure can withstand thermal shock cycles of ≥1000 times at a working temperature of 1000°C.

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