High-fatigue-resistance nickel-based alloy for fused salt photoelectric heating and preparation method of high-fatigue-resistance nickel-based alloy

Abstract

The invention discloses a high-fatigue-resistance nickel-based alloy for fused salt photoelectric heating and a preparation method of the high-fatigue-resistance nickel-based alloy. Belongs to the field of molten salt photoelectric heating corrosion-resistant nickel-based alloys, the high-fatigue-resistance nickel-based alloy for molten salt photoelectric heating is N06625 nickel-based alloy, solution heat treatment is carried out, the solution temperature is 1150 DEG C, the heat preservation time is 30 min, long-term aging treatment is carried out on the N06625 nickel-based alloy, the aging temperature is 550 DEG C, and the aging time is 200 h, 500 h, 1000 h and 2000 h; the nickel-based alloy disclosed by the invention has high fatigue resistance, and the material can work for a long time under cyclic stress or alternating load without fatigue damage. The material with good fatigue resistance can effectively inhibit crack initiation and propagation, and the service life is prolonged; in addition, the nickel-based alloy has high corrosion resistance in a molten salt environment, and the material keeps stable capacity under chemical, electrochemical or environmental erosion and resists damage such as oxidation, pitting corrosion and stress corrosion.

Description

Technical Field

[0001] The present invention belongs to the field of molten salt photoelectric heating corrosion-resistant nickel-based alloys, and relates to a nickel-based alloy for molten salt photoelectric heating with high fatigue resistance and a preparation method thereof. Background Art

[0002] As the core energy conversion unit of the solar thermal system, the performance and reliability of the molten salt transfer pipe are directly related to the efficiency, operation life and economic feasibility of the entire system. During the solar thermal power generation process, the molten salt transfer pipe plays a key role in efficiently converting solar energy into heat energy, and then driving a heat engine to generate electricity. The efficient realization of this energy conversion process depends on the stable operation of the key component nickel-based alloy inside the molten salt transfer pipe. The corrosion and damage of nickel-based alloys in a molten salt environment usually show a multi-scale material degradation process. High-temperature molten salt interacts with the alloy surface through redox reactions, triggering an intergranular corrosion network. At the same time, active elements (such as sulfur and oxygen) in the molten salt selectively corrode alloy elements (such as chromium and aluminum), resulting in surface depletion. In a dynamic corrosion environment, the convection of molten salt caused by temperature gradients will accelerate the peeling of corrosion products, forming pitting and ulcer-like morphologies. Under stress coupling conditions, the corrosion front will promote crack initiation, ultimately leading to catastrophic failure of the alloy's mechanical properties. This corrosion behavior is jointly regulated by the molten salt composition, oxygen partial pressure and the alloy microstructure, showing non-uniform material loss and embrittlement. Nickel-based alloys are exposed to an extremely complex multi-physical field coupling environment for a long time and face multiple severe challenges. These challenges not only come from the strong dynamic corrosion effect generated by the binary molten nitrate (mainly composed of 60% NaNO3 and 40% KNO3) flowing inside the pipe at high temperatures (290 - 565 °C), but also include the selective dissolution of grain boundaries caused by trace chloride ion impurities in the molten salt, further exacerbating the weakening of the pipe along the grain boundaries.

[0003] In addition, affected by meteorological conditions, nickel-based alloys also need to withstand high-frequency and high-speed thermal shocks. This thermal shock not only has a fast temperature change rate, up to 2.5 - 5 °C / s, but also the number of daily cycles can be as high as dozens of times. At the same time, nickel-based alloys also need to withstand a high radiation flux of up to 800 kW / m 2 which is equivalent to 800 times the sunlight intensity, and an internal pressure load of 1.0 MPa. The combined action of these extreme conditions causes nickel-based alloys to face the combined damage of low-cycle fatigue and thermo-mechanical fatigue, further shortening their service life. Summary of the Invention

[0004] Aiming at the above problems, the purpose of the present invention is to disclose a nickel-based alloy for molten salt photoelectric heating with high fatigue resistance and a preparation method thereof. By solution treatment and long-term aging treatment, the fatigue resistance of the nickel alloy pipe is improved, and it has high molten salt corrosion resistance.

[0005] The technical solution of the present invention is as follows: A nickel-based alloy for molten salt photoelectric heating with high fatigue resistance, the nickel-based alloy is N06625 nickel-based alloy, and its chemical components are calculated by mass percentage as follows: Cr: 21.36 wt.%, Mo: 7.82 wt.%, Nb: 4.11 wt.%, Fe: 3.94 wt.%, and the balance is Ni.

[0006] Furthermore, a preparation method of a nickel-based alloy for molten salt photoelectric heating with high fatigue resistance. First, polish the surface of the N06625 nickel-based alloy, then conduct solution heat treatment, and then conduct long-term aging treatment to obtain a solution-state nickel-based alloy, so that uniformly refined γ' phase and carbides are precipitated in the alloy.

[0007] Furthermore, the solution temperature is 1150 °C and the holding time is 30 min.

[0008] Furthermore, the aging temperature for the long-term aging treatment is 550 °C, and the aging times are 200 h, 500 h, 1000 h, and 2000 h, so as to obtain a nickel-based alloy microstructure with refinement and uniformly fine precipitation phases as required.

[0009] Furthermore, the operation process for detecting the corrosion resistance of the solution-state nickel-based alloy after long-term aging treatment is as follows:

[0010] Conduct long-term molten salt corrosion on the solution-state nickel-based alloy. Use solar salt as the molten salt material. Place the nickel-based alloy specimen in an alumina square covered crucible with dimensions of 200×100×50 mm, and fill the crucible with a powder of 60% NaNO3 and 40% KNO3 in a ratio of 3:2; use a KSL-1000X box furnace to conduct a molten salt corrosion test on the nickel-based alloy, and observe the corrosion layer through SEM to detect the corrosion resistance of the material.

[0011] Furthermore, the molten salt material is composed of 60% NaNO3 and 40% KNO3 together;

[0012] The time for molten salt corrosion in the crucible is 2000 h, and the corrosion temperature is 550 °C.

[0013] Further, the operation process of detecting the anti-fatigue performance of the solution-treated nickel-based alloy after long-term aging is as follows: All low-cycle fatigue experiments are carried out on an 8802 10T electro-hydraulic servo fatigue testing machine. After removing the rust layer on the surface of the nickel-based alloy to expose the bright metal surface, on the basis of the machined specimen, in order to remove the machining marks and surface scratches remaining on the surface of the specimen during machining, the surface and side surfaces of the working section of the specimen are subjected to rough turning - finish turning - grinding - polishing treatment in accordance with the method of GB / T 15248-2008. After polishing, the specimen is degreased. The low-cycle fatigue is carried out according to GB / T 15248-2008 "Test Method for Axial Equal-Amplitude Low-Cycle Fatigue of Metallic Materials", and the loading mode of axial tension-compression fully reversed external total strain amplitude control is adopted, and the external nominal total strain amplitude Δε t / 2 is 0.15%, 0.2%, 0.25%, 0.3%, 0.4% and 0.5%. All fatigue experiments are carried out until the nickel-based alloy fractures, and the corresponding number of cycles at this time is used as the fatigue life N of the alloy under the corresponding experimental conditions f .

[0014] Further, the strain ratio Re of the fatigue test is -1.

[0015] Further, the fatigue test adopts a triangular waveform.

[0016] Further, the cyclic frequency adopted in the fatigue test is 1 Hz.

[0017] Further, after long-term aging, the dislocation density in the dislocation substructure after fatigue deformation is greater, more dislocation tangles are generated, so a greater fatigue resistance is generated and the fatigue life is higher.

[0018] Principle of the invention: Long-term aging treatment can change the dislocation substructure of metallic materials, increase their dislocation density and generate more dislocation tangles; dislocations are line defects caused by irregular atomic arrangements in crystalline materials, and their movement leads to plastic deformation; during fatigue deformation, the slip and interaction of dislocations are one of the main mechanisms of fatigue damage.

[0019] After long-term aging treatment, the dislocations in metallic materials will rearrange and aggregate; in the initial stage of aging, the dislocations are activated, and through movements such as dislocation slip and climb, the opposite-sign dislocations cancel each other out, and the dislocation network forms a dislocation wall, and the dislocation density decreases somewhat; but as the aging time prolongs, the dislocations will undergo complex interactions, and the dislocations entangle into dislocation cells; dislocation cells are substructures formed by a large number of dislocation tangles, which can hinder the further movement of dislocations and increase the resistance to dislocation slip.

[0020] Meanwhile, dislocation tangles also cause changes in the stress distribution within the material; local stress concentration occurs in the dislocation tangle regions, but to a certain extent, this stress concentration can improve the work hardening ability of the material; when the material is subjected to cyclic loading, dislocation tangles can effectively prevent the initiation and propagation of cracks, thereby improving the fatigue resistance of the material and extending its fatigue life.

[0021] The beneficial effects of the present invention are as follows: 1. The present invention improves the microstructure of nickel-based alloys through long-term aging treatment. The molten salt corrosion of the solution-treated nickel-based alloy is a process of uniform corrosion, with a very flat surface and no internal corrosion; the thickness of the NiO corrosion layer is very thin, and when the corrosion time is 200 h, the corrosion thickness is only 0.2 μm; as the molten salt corrosion time increases, the corrosion gradually intensifies and the corrosion layer thickness also gradually increases, but it is still uniform corrosion; 2. After the aging treatment of the metal material according to the present invention, its fatigue resistance is significantly enhanced and its fatigue life is greatly improved; the alloy composition can be flexibly and freely adjusted, the process flow is simple, the investment is small, and it is easy to fabricate complex nickel-based alloy plates. Brief Description of the Drawings

[0022] Figure 1 It is a schematic diagram of the fatigue source area in the fatigue fracture of N06625 nickel-based alloy obtained in Example 3 of the present invention under a strain amplitude of 0.5%;

[0023] Figure 2 It is a schematic diagram of the crack propagation area in the fatigue fracture of N06625 nickel-based alloy obtained in Example 3 of the present invention under a strain amplitude of 0.5%;

[0024] Figure 3 It is a schematic diagram of the instantaneous fracture area in the fatigue fracture of N06625 nickel-based alloy obtained in Example 3 of the present invention under a strain amplitude of 0.5%;

[0025] Figure 4 It is a schematic diagram of the dislocation distribution within the grains of the solution-treated N06625 nickel-based alloy obtained in Example 4 of the present invention after fatigue deformation;

[0026] Figure 5 It is a schematic diagram of the dislocation distribution in the twin boundaries of the solution-treated N06625 nickel-based alloy obtained in Example 4 of the present invention after fatigue deformation;

[0027] Figure 6 It is a schematic diagram of the dislocation distribution in the grain boundaries of the solution-treated N06625 nickel-based alloy obtained in Example 4 of the present invention after fatigue deformation;

[0028] Figure 7 It is a schematic diagram of the dislocation distribution in the precipitation phases of the solution-treated N06625 nickel-based alloy obtained in Example 4 of the present invention after fatigue deformation;

[0029] Figure 8 It is a schematic diagram of the dislocation distribution in the dislocation tangles after fatigue deformation of the solution-treated N06625 nickel-based alloy obtained in Example 4 of the present invention;

[0030] Figure 9 It is a schematic SEM cross-section diagram of the solution-treated N06625 nickel-based alloy obtained in Example 5 of the present invention after 2000 h of molten salt corrosion;

[0031] Figure 10 It is a schematic SEM scratch diagram of the solution-treated N06625 nickel-based alloy obtained in Example 5 of the present invention after 2000 h of molten salt corrosion. Detailed implementation manners

[0032] The following further elaborates on the specific technical solutions of the present invention with reference to specific examples.

[0033] As shown in the figure, for a nickel-based alloy for molten salt photoelectric heating with high fatigue resistance of the present invention, in order to improve the low-cycle fatigue performance deterioration and cracking caused by the molten salt corrosion process during the use of traditional nickel-based alloys as materials for molten salt photoelectric heating, the nickel-based alloy for molten salt photoelectric heating with high fatigue resistance is N06625 nickel-based alloy. The surface of the nickel-based alloy is polished and solution heat treatment is carried out. The solution temperature and holding time are 1150 °C and 30 min respectively, so as to obtain a solution-treated nickel-based alloy, and uniformly refined γ' phase and carbides are precipitated in the alloy. The solution-treated nickel-based alloy has better microstructure and mechanical properties than the original nickel-based alloy.

[0034] Further, the nickel-based alloy is N06625 nickel-based alloy, and the N06625 nickel-based alloy includes the following elements in mass percentages: Cr: 21.36 wt.%, Mo: 7.82 wt.%, Nb: 4.11 wt.%, Fe: 3.94 wt.%, and the balance is Ni.

[0035] Further, long-term aging treatment is carried out after solution heat treatment; that is: the N06625 nickel-based alloy is subjected to long-term aging treatment, and its aging temperature is 550 °C, and the aging times are 200 h, 500 h, 1000 h, and 2000 h, so as to obtain a nickel-based alloy microstructure with refinement and uniformly fine precipitation phases. These precipitation phases can effectively hinder dislocation movement and improve the strength and fatigue resistance of the alloy. By controlling the aging temperature and time, the size and distribution of the precipitation phases can be optimized to avoid coarsening, thus maintaining good high-temperature stability.

[0036] Further, it is subjected to 2000 h of molten salt corrosion in a powder of 60% NaNO3 and 40% KNO3 with a ratio of 3:2, and the corrosion temperature is 550 °C, so as to detect the corrosion resistance of the material by observing the corrosion layer through SEM, and the molten salt corrosion resistance characteristics of the solution-treated nickel-based alloy are improved.

[0037] Furthermore, the low-cycle fatigue test is carried out until the metal fractures, with nominal total strain amplitudes of 0.15%, 0.2%, 0.25%, 0.3%, 0.4% and 0.5% applied. By comparing the fatigue life and cyclic stress of the material under different strain amplitude conditions, the nickel-based alloy under the optimal long-term aging time and temperature conditions can be obtained, and this nickel-based alloy has the best fatigue resistance and strength.

[0038] A loading mode with axial tension-compression fully reversed external total strain amplitude control is adopted, the strain ratio Re = -1, a triangular waveform is used, and nominal total strain amplitudes of 0.15%, 0.2%, 0.25%, 0.3%, 0.4% and 0.5% are applied. The cyclic frequency used is 1 Hz. All fatigue experiments are carried out until the nickel-based alloy fractures, and the corresponding number of cycles at this time is taken as the fatigue life N of the alloy under the corresponding experimental conditions. f 。

[0039] Furthermore, the strain ratio Re of the fatigue test is -1; a triangular waveform is used in the fatigue test; the cyclic frequency used in the fatigue test is 1 Hz.

[0040] Example 1

[0041] A preparation method of a nickel-based alloy for molten salt photothermal heating with high fatigue resistance includes the following steps:

[0042] (1) Pretreat the nickel-based superalloy: Select the N06625 nickel-based alloy, remove the surface oil stains and stains with alcohol or acetone, remove the rust on the substrate surface, and form a rough surface on the substrate surface;

[0043] (2) Perform long-term aging treatment on the N06625 nickel-based alloy, with the aging temperature being 550 °C and the aging times being 200 h, 500 h, 1000 h and 2000 h;

[0044] (3) Adopt a loading mode with axial tension-compression fully reversed external total strain amplitude control, the strain ratio Re = -1, use a triangular waveform, apply nominal total strain amplitudes of 0.15%, 0.2%, 0.25%, 0.3%, 0.4% and 0.5%, and the cyclic frequency used is 1 Hz;

[0045] All fatigue experiments are carried out until the nickel-based alloy bar fractures, and the corresponding number of cycles at this time is taken as the fatigue life N of the alloy under the corresponding experimental conditions. f 。

[0046] Table 1 shows the fatigue life of nickel-based alloys under different heat treatment processes. Compared with the solution-treated nickel-based alloy, the fatigue life of the nickel-based alloy after 1000 h of long-term aging is significantly improved. After the aging time reaches 2000 h, under the conditions of low strain amplitudes (0.15%, 0.2%), the fatigue life of the solution-treated sample is improved compared with that after 1000 h of aging, but under the conditions of strain amplitudes of 0.25%, 0.3%, 0.4%, and 0.5%, the change in its fatigue life is not obvious.

[0047] Table 1 Fatigue life of nickel-based alloys under different heat treatment processes

[0048] Strain amplitude / % 1.5％ 0.2％ 0.25％ 0.3％ 0.4％ 0.5％ Number of cycles in solution state 4437 1292 873 604 298 164 Number of cycles after 1000h aging 6205 2390 1123 718 519 348 Number of cycles after 2000h aging 9095 2901 1190 706 518 337

[0049] Example 2

[0050] A preparation method of a nickel-based alloy for molten salt optoelectronic heating with high fatigue resistance, comprising the following steps:

[0051] (1) Pretreat the nickel-based superalloy: Select the N06625 nickel-based alloy, remove the surface oil stains and stains with alcohol or acetone, remove the rust on the surface of the substrate, and form a rough surface on the surface of the substrate;

[0052] (2) Perform long-term aging treatment on the N06625 nickel-based alloy, with the aging temperature of 550 °C and the aging times of 200 h, 500 h, 1000 h, and 2000 h;

[0053] (3) After the specimen is polished, use a full-range extensometer with a range of 10 mm to perform tensile tests at a strain rate of 10 -3 s -1 . To ensure the accuracy of the test data, each tensile experiment is repeated three times.

[0054] As shown in Table 2, the initial tensile strength of the solution-treated N06625 nickel-based alloy is 913 MPa, and the elongation after fracture is 42.9%. As the aging time extends, the mechanical properties of the alloy do not change significantly. When the aging time t = 200 h, the tensile strength and elongation after fracture are 907 MPa and 45.1% respectively, showing no significant change compared with the non-aged state. When the aging time is extended to t = 500 h, compared with the non-aged state, the tensile strength increases slightly by 7 MPa, with an increase rate of about 0.77%, while the elongation after fracture decreases slightly by 1.1%, and the overall change range is small. When the aging time is further extended to t = 1000 h, the tensile strength rises slightly to 950 MPa, and at the same time the plasticity decreases slightly, with the elongation after fracture being 42.3%. When the aging time reaches t = 2000 h, the tensile strength is significantly increased to 1009 MPa, an increase of about 10.5% compared with the non-aged state. However, the plasticity decreases significantly, and the elongation after fracture decreases from 42.9% to 36.2%, with a decrease rate of 15.6%.

[0055] Mechanical property data of nickel-based alloys under different heat treatment processes in Table 2

[0056]

[0057] Example 3

[0058] A preparation method of a nickel-based alloy for molten salt photoelectric heating with high fatigue resistance, comprising the following steps:

[0059] (1) Pretreat the nickel-based superalloy: Select N06625 nickel-based alloy, remove surface oil stains and dirt with alcohol or acetone, remove rust on the substrate surface, and form a rough surface on the substrate surface;

[0060] (2) Perform long-term aging treatment on N06625 nickel-based alloy, with an aging temperature of 550 °C and aging times of 200 h, 500 h, 1000 h, and 2000 h;

[0061] (3) Figure 1 - 3 They are the fatigue source area, fatigue crack propagation area, and instantaneous fracture area of the fatigue fracture surface of the solution-treated N06625 nickel-based alloy under a 0.5% strain amplitude; The fatigue crack initiates from the free surface of the specimen in a transgranular manner, and the early stage of the fatigue crack also propagates in a transgranular manner, showing obvious radial textures, and the area occupied by the transgranular fatigue crack source area is small; From the microscopic morphology in the stable propagation stage of the fatigue crack, very clear fatigue striations can be seen in the fatigue crack propagation area; The instantaneous fracture area of the low-cycle fatigue specimen shows obvious dimple morphology, showing ductile fracture, indicating that the N06625 nickel-based alloy has good fatigue resistance, and this part accounts for the largest area and exists in the center of the sample fracture.

[0062] Example 4

[0063] A preparation method of a nickel-based alloy for molten salt photoelectric heating with high fatigue resistance, comprising the following steps:

[0064] (1) Pretreat the nickel-based superalloy: Select N06625 nickel-based alloy, remove surface oil stains and dirt with alcohol or acetone, remove rust on the substrate surface, and form a rough surface on the substrate surface;

[0065] (2) Perform long-term aging treatment on N06625 nickel-based alloy, with an aging temperature of 550 °C and aging times of 200 h, 500 h, 1000 h, and 2000 h;

[0066] (3) Figure 4 - 8They are respectively the dislocation distributions in the grains, twin boundaries, grain boundaries, precipitation phases, and dislocation tangles of the solution-treated N06625 nickel-based alloy during fatigue deformation; the slip bands exhibit a series of linearly arranged structures parallel to each other, with uniform spacing and consistent directions, reflecting the regular movement of dislocations during the plastic deformation of the material; the formation mechanism of the slip bands is mainly related to the activation of slip systems in the crystal structure, and their uniformity indicates that the material has experienced a relatively uniform stress distribution during deformation; the dislocation density is very high, and strong interactions occur between dislocations and twin boundaries, as well as between dislocations and grain boundaries, effectively hindering the movement of dislocations and causing a large number of dislocations to pile up at twin boundaries and grain boundaries; at the same time, high-density dislocations are wound around the precipitation phases, resulting in severe dislocation pile-up near them, and the precipitation phases further pin the dislocations; relatively complex dislocation configurations such as dislocation walls and dislocation tangles are formed; the number of NbC secondary phases precipitated in the sample increases significantly, and these nano-scale precipitation phases are uniformly distributed in the matrix; secondly, the NbC secondary phases are more likely to segregate at grain boundaries, forming a continuous network of grain boundary precipitation phases; this change in microstructure has an important impact on the mechanical properties of the material: on the one hand, the increased NbC secondary phases provide more dislocation pinning points, enhancing the strength of the material; on the other hand, the segregation of NbC phases at grain boundaries helps to improve the grain boundary bonding strength, thereby enhancing the fatigue resistance of the material.

[0067] Example 5

[0068] A preparation method of a nickel-based alloy for molten salt photothermal heating with high fatigue resistance, comprising the following steps:

[0069] (1) Pretreat the nickel-based superalloy: Select the N06625 nickel-based alloy, remove the surface oil stains and stains with alcohol or acetone, remove the rust on the substrate surface, and form a rough surface on the substrate surface;

[0070] (2) Perform long-term aging treatment on the N06625 nickel-based alloy at an aging temperature of 550 °C for aging times of 200 h, 500 h, 1000 h, and 2000 h;

[0071] (3) Figure 9 - 10They are respectively the cross-sectional SEM photo and the scratch photo of the solution-treated N06625 nickel-based alloy after 2000 h of molten salt corrosion; the molten salt corrosion of the solution-treated nickel-based alloy is a process of uniform corrosion, with a very flat surface and no internal corrosion; the thickness of the NiO corrosion layer is very thin, and as the molten salt corrosion time increases, the corrosion gradually intensifies and the thickness of the corrosion layer also gradually increases, but it is still uniform corrosion, and the thickness of the corrosion layer is 0.9 μm at the end of 2000 h; the solution-treated N06625 alloy shows relatively serious breakage and peeling in the scratch test at different aging times, which is due to the insufficient adhesion of the film, and it is easy to break and peel off under external mechanical pressure; the nickel-based alloy has good corrosion resistance after long-term aging.

Claims

1. A nickel-based alloy for molten salt photoelectric heating with high fatigue resistance, characterized in that, The nickel-based alloy is N06625 nickel-based alloy, and its chemical components are by mass percentage: Cr: 21.36 wt.%, Mo: 7.82 wt.%, Nb: 4.11 wt.%, Fe: 3.94 wt.%, and the balance is Ni.

2. The preparation method of a nickel-based alloy for molten salt optoelectronic heating with high fatigue resistance according to claim 1, characterized in that, First, polish the surface of the N06625 nickel-based alloy, then conduct solution heat treatment, and then conduct long-term aging treatment to obtain a solution-state nickel-based alloy, so that uniformly refined γ'-phase and carbides precipitate in the alloy.

3. The preparation method of a nickel-based alloy for molten salt optoelectronic heating with high fatigue resistance according to claim 2, characterized in that, The solution temperature is 1150 °C and the holding time is 30 min.

4. The preparation method of a nickel-based alloy for molten salt optoelectronic heating with high fatigue resistance according to claim 2, characterized in that, The aging temperature for the long-term aging treatment is 550 °C, and the aging times are 200 h, 500 h, 1000 h, and 2000 h, so as to obtain a nickel-based alloy microstructure with refinement and uniform and fine precipitation phases as required.

5. The preparation method of a nickel-based alloy for molten salt optoelectronic heating with high fatigue resistance according to claim 2, characterized in that, The operation process for detecting the corrosion resistance of the solution-state nickel-based alloy after long-term aging treatment is as follows: Conduct long-term molten salt corrosion on the solution-state nickel-based alloy. Use solar salt as the molten salt material. Place the nickel-based alloy specimen in an alumina square covered crucible with dimensions of 200×100×50 mm, and fill the crucible with 60% NaNO3 and 40% KNO3 powder in a ratio of 3:2; use a KSL-1000X box furnace to conduct molten salt corrosion test on the nickel-based alloy, and observe the corrosion layer through SEM to detect the corrosion resistance of the material.

6. The preparation method of a nickel-based alloy for molten salt optoelectronic heating with high fatigue resistance according to claim 5, characterized in that, The molten salt material is composed of 60% NaNO3 and 40% KNO3 together; The time for molten salt corrosion in the crucible is 2000 h, and the corrosion temperature is 550 °C.

7. The preparation method of a nickel-based alloy for molten salt optoelectronic heating with high fatigue resistance according to claim 2, characterized in that, The operation process for detecting the fatigue resistance of the solution-state nickel-based alloy after long-term aging treatment is: all fatigue experiments are carried out on an 8802 10T type electro-hydraulic servo fatigue testing machine; Remove the rust layer on the surface of the nickel-based alloy to expose the bright metal surface. On the basis of the machined specimen, conduct rough machining - finish machining - grinding - polishing treatment on the working section surface and side surface of the specimen. After polishing, degrease the specimen. Adopt a loading mode with axial tension-compression fully reversed externally applied total strain amplitude control, and the externally applied nominal total strain amplitude Δε t / 2 is 0.15%, 0.2%, 0.25%, 0.3%, 0.4% and 0.5%; All fatigue experiments were carried out until the nickel-based alloy fractured, and the corresponding number of cycles at this time was taken as the fatigue life N of the alloy under the corresponding experimental conditions f .

8. The preparation method of a nickel-based alloy for molten salt optoelectronic heating with high fatigue resistance according to claim 7, characterized in that, The strain ratio Re of the fatigue test is -1.

9. The preparation method of a nickel-based alloy for molten salt optoelectronic heating with high fatigue resistance according to claim 7, characterized in that, The fatigue test adopts a triangular waveform.

10. The preparation method of a nickel-based alloy for molten salt photoelectric heating with high fatigue resistance according to claim 7, characterized in that, The cyclic frequency adopted in the fatigue test is 1 Hz.

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