Nickel-based alloy and method for improving radiation resistance of nickel-based alloy and nickel-based alloy thin-walled pipe

Abstract

The application discloses a nickel-based alloy and a method for improving the radiation resistance of a nickel-based alloy and a thin-walled pipe of the nickel-based alloy. The method for improving the radiation resistance of the nickel-based alloy comprises: laser shocking the nickel-based alloy; wherein the laser shock has a laser energy of 50-100 mJ, a wavelength of 532 nm, a pulse width of 8-15 ns, and a spot diameter of 0.2-0.5 mm; and the dislocation loop density of the nickel-based alloy after the laser shocking is less than 2.5*10 22 m ‑3 after 20 dpa irradiation. The alloy prepared by the method has a precipitated phase dissolution rate caused by irradiation which is reduced by 40.7% and an irradiation dislocation loop size which is reduced by more than 5% and a density which is reduced by nearly 30% under an irradiation damage dose of 20 dpa, and the alloy macro hardness change delta H is reduced by 26.7% compared with the nickel-based alloy without laser shocking.

Description

Technical Field

[0001] This application relates to the field of alloy manufacturing technology, specifically to a nickel-based alloy and a method for improving the radiation resistance of nickel-based alloys and thin-walled nickel-based alloy tubing. Background Technology

[0002] With the development of advanced nuclear energy technology, increasingly stringent requirements are being placed on the performance of nuclear reactor structural materials. Materials need to maintain stable performance under higher temperatures and higher neutron fluxes to ensure the safe operation of nuclear reactors. GH4169 nickel-based superalloy is a material with high strength, high temperature resistance, and corrosion resistance. It is used as a spring material in pressurized water reactors, a candidate material for target and cladding applications in accelerator drive systems (ADS), and is also a key candidate material for fourth-generation reactors. However, it suffers from irradiation softening and embrittlement under high flux irradiation, posing potential risks to its further application in advanced reactors with even higher neutron fluxes. Summary of the Invention

[0003] To address the aforementioned deficiencies in the field, this application aims to provide a nickel-based alloy and a method for improving the radiation resistance of nickel-based alloys and thin-walled nickel-based alloy tubing.

[0004] According to one aspect of this application, a method for improving the radiation resistance of nickel-based alloys is provided, comprising: subjecting the nickel-based alloy to laser shock; wherein the laser energy of the laser shock is 50 mJ-100 mJ, the wavelength is 532 nm, the pulse width is 8 ns-15 ns, and the spot diameter is 0.2-0.5 mm; after laser shock, the dislocation loop density of the nickel-based alloy after irradiation at 20 dpa is less than 2.5 × 10⁻⁶. 22 m -3 The precipitate density of the nickel-based alloy after laser shock irradiation at 20 dpa is less than 7.4 μm. -2 .

[0005] According to some embodiments of this application, the number of laser impacts is 3-5 times.

[0006] According to some embodiments of this application, laser shock is performed at 300-350°C to maintain the flow of deionized water on the surface of the nickel-based alloy.

[0007] According to another aspect of this application, a method for improving the radiation resistance of nickel-based alloy thin-walled tubing is also provided, comprising: introducing a nano-SiO2-polyethylene glycol solution into the interior of the nickel-based alloy thin-walled tubing, welding and sealing the end, and then subjecting the nickel-based alloy thin-walled tubing to laser shock irradiation; wherein the laser energy of the laser shock irradiation is 50 mJ-100 mJ, the wavelength is 532 nm, the pulse width is 8 ns-15 ns, and the spot diameter is 0.2-0.5 mm; after laser shock irradiation, the dislocation loop density of the nickel-based alloy thin-walled tubing after 20 dpa irradiation is less than 2.5 × 10⁻⁶. 22 m -3 The precipitate density of the nickel-based alloy thin-walled tubing after laser shock irradiation at 20 dpa is less than 7.4 μm. -2 .

[0008] According to some embodiments of this application, the particle size of nano-SiO2 is 100 nm-200 nm.

[0009] According to some embodiments of this application, the mass ratio of nano-SiO2 to polyethylene glycol is 0.67-1.22.

[0010] According to some embodiments of this application, the amount of nano-SiO2-polyethylene glycol solution introduced is 55%-70% of the internal capacity of the nickel-based alloy thin-walled tube.

[0011] According to some embodiments of this application, laser shock is performed at 300°C-350°C while maintaining the flow of deionized water on the surface of the nickel-based alloy;

[0012] The laser impact is performed 3-5 times.

[0013] According to some embodiments of this application, the process further includes: completing the laser shock, waiting for the alloy tube to cool to 100°C-120°C, cutting off the seals at both ends, and pouring out the nano-SiO2-polyethylene glycol solution.

[0014] According to another aspect of this application, a nickel-based alloy is provided, prepared by the above method;

[0015] The dislocation ring density of irradiated nickel-based alloys is less than 2.5 × 10⁻⁶. 22 m -3 ;

[0016] The density of precipitated phases in the irradiated nickel-based alloy is less than 7.4 μm. -2 . Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the metallographic structure of a nickel-based alloy in an example embodiment of this application (a and b are before laser shock; c and d are after laser shock).

[0018] Figure 2This is a schematic diagram showing the dissolution rate of the precipitated phase after irradiation of a nickel-based alloy, which is an example embodiment of this application.

[0019] Figure 3 This is a schematic diagram of the density / size of the precipitated phase after irradiation of a nickel-based alloy, as shown in the example embodiment of this application.

[0020] Figure 4 This is a schematic diagram of the dislocation ring density / size of a nickel-based alloy after irradiation, as shown in the example embodiment of this application.

[0021] Figure 5 This is a schematic diagram showing the hardness values ​​of a nickel-based alloy in an example embodiment of this application. Detailed Implementation

[0022] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] It should be particularly noted that similar substitutions and modifications made to this application are obvious to those skilled in the art, and they are all considered to be included in this application. Those skilled in the art can obviously make modifications or appropriate alterations and combinations to the methods and applications described herein without departing from the content, spirit, and scope of this application to implement and apply the technology of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0024] Unless otherwise specified, this application shall be made in accordance with conventional conditions or conditions recommended by the manufacturer. The raw materials or excipients used, as well as the reagents or instruments used, whose manufacturers are not specified, are all conventional products that can be obtained commercially.

[0025] The following is a detailed description of this application.

[0026] Nickel-based superalloys are precipitation-strengthened alloys, in which the dispersed γ' and γ'' phases are the main sources of their strength and ductility. Irradiation can cause amorphization of the γ' and γ'' phases in nickel-based superalloys, the severity of which is directly proportional to the dose and dose rate of neutron irradiation. When high temperatures intensify the diffusion of atoms in the material, a large number of solute atoms diffuse into the matrix from the disordered regions of the precipitates caused by irradiation, leading to severe dissolution of the precipitates. This manifests in the macroscopic mechanical properties of the material as a significant softening of the ultimate tensile strength.

[0027] Nickel-based superalloys (such as GH4169 nickel-based superalloy) also experience irradiation embrittlement under irradiation. This is mainly due to the continuous accumulation of irradiation defects in the material caused by cascading collisions induced by neutrons. These defects gradually grow into immobile defects such as dislocation loops and stacking fault tetrahedra, hindering dislocation slip during material deformation. The nucleation sites of these defects easily become crack initiation sites. In addition, irradiation softening and irradiation embrittlement can couple with other factors such as stress and corrosion, forming more complex material failure mechanisms such as irradiated stress corrosion.

[0028] In some examples, this application provides a nickel-based alloy and a method for improving the radiation resistance of the nickel-based alloy. Optionally, it is a method for preparing a radiation-resistant nickel-based alloy based on laser shock irradiation technology. The alloy prepared by this method, under an irradiation damage dose of 20 dpa, exhibits a 40.7% decrease in the dissolution rate of irradiated precipitates compared to the untreated nickel-based alloy, a reduction of over 5% in the size of irradiated dislocation loops, a decrease in density of nearly 30%, and a 26.7% decrease in the change in macroscopic hardness ΔH compared to the untreated laser-shocked nickel-based alloy.

[0029] In some examples, this application found that nickel-based alloys exhibit irradiation softening and irradiation embrittlement under long-term irradiation, due to the dissolution of precipitated phases and the growth of dislocation rings. Since the γ' and γ'' phases are crucial to the excellent high-temperature mechanical properties and corrosion resistance of nickel-based alloys, if the precipitation of these two phases is suppressed before service through heat treatment or other means, the prepared material will not exhibit irradiation softening, but its high-temperature mechanical properties will not meet the requirements. However, if these two second phases are retained, the irradiation softening problem cannot be solved.

[0030] The aforementioned contradictions are the main reasons for the current lack of improvement in the radiation resistance of nickel-based superalloys. Furthermore, the dissolution of precipitated phases accelerates the growth rate of irradiated dislocation loops. In addition, irradiation softening and embrittlement can couple with other factors such as stress and corrosion, forming more complex material failure mechanisms such as irradiated stress corrosion. Therefore, this application aims to suppress the dissolution of precipitated phases and the growth of dislocation loops in nickel-based alloys under irradiation conditions, thereby improving their radiation resistance. Moreover, this method is suitable for the large-scale manufacturing of large-scale components.

[0031] This application reveals that improving the radiation resistance of materials must be done while simultaneously maintaining their formability. Thin-walled tubes are widely used in the nuclear industry. Direct laser shock processing on thin-walled tubes can lead to deformation or even breakage due to intense deformation. On the one hand, to improve the radiation resistance, the power density of the laser shock must be high enough to induce sufficient plastic deformation within the material; on the other hand, to maintain dimensional accuracy, the laser shock must not cause overall deformation or breakage of the material. These two aspects are contradictory. Balancing these two aspects is particularly difficult for thin-walled components.

[0032] In some examples, this application also provides a method for improving the radiation resistance of thin-walled nickel-based alloy tubing. This method designs a suitable laser shock processing method for thin-walled tubing, which can reduce the reflection of instantaneous laser shock force during processing and avoid workpiece deformation and breakage caused by laser shock.

[0033] The technical solution of this application will be further described below with reference to specific embodiments.

[0034] Example 1

[0035] Processing target: 0.5 mm thick GH4169 pipes that have undergone solution treatment and double-stage aging heat treatment, with a processing length of 0.5 m.

[0036] Laser shock:

[0037] A nano-SiO2-polyethylene glycol solution, comprising 70% of the total volume of the alloy tube, is introduced into the GH4169 tube. The nano-SiO2 particles in the solution have a size of 100 nm, and the mass ratio of SiO2 particles to polyethylene glycol is 0.8. The two ends of the alloy tube are sealed by welding, and the sealed alloy tube is heated to 300°C by induction heating.

[0038] Laser shock treatment was performed on the outer surface of the GH4169 alloy tube at 300℃. The laser energy was 50 mJ, the wavelength was 532 nm, the pulse width was 8 ns, the spot diameter was 0.2 mm, and the spot overlap rate was 50%. During the processing, deionized water was kept flowing on the outer surface of the tube to cover the laser spot processing area. The temperature of the deionized water outside the tube was between room temperature and 50℃. The laser shock uniformly covered the outer surface of the alloy tube, and the shock was repeated 3-5 times to ensure the uniformity of the shock processing.

[0039] After laser shock is completed, and the alloy tube is cooled to 100℃-120℃, the 2 cm-5 cm area of ​​the sealed section at both ends is cut off, and the polyethylene glycol solution of nano-SiO2 particles is poured out. The solution can be collected and reused.

[0040] The inner and outer walls of the GH4169 alloy tube after laser shock processing are rinsed with deionized water, rinsed with ethanol, and dried to complete the processing.

[0041] Example 2

[0042] Processing target: 0.5 mm thick GH4169 pipes that have undergone solution treatment and double-stage aging heat treatment, with a processing length of 5.0 m.

[0043] Laser shock:

[0044] A nano-SiO2-polyethylene glycol solution, comprising 55% of the total volume of the alloy tube, is introduced into the GH4169 tube. The nano-SiO2 particles in the solution have a size in the range of 200 nm, and the mass ratio of SiO2 particles to polyethylene glycol is 1.2. The two ends of the alloy tube are sealed by welding, and the sealed alloy tube is heated to 300°C by induction heating.

[0045] Laser shock treatment was performed on the outer surface of GH4169 alloy tubes at 300℃. The laser energy was 100 mJ, wavelength was 532 nm, pulse width was 15 ns, spot diameter was 0.5 mm, and spot overlap rate was 50%. During the processing, deionized water was kept flowing on the outer surface of the tube to cover the laser spot processing area. The temperature of the deionized water outside the tube was between room temperature and 50℃. The laser shock uniformly covered the outer surface of the alloy tube, and the shock was repeated 3-5 times to ensure the uniformity of the shock processing.

[0046] After laser shock is completed, and the alloy tube is cooled to 100℃-120℃, the 2 cm-5 cm area of ​​the sealed section at both ends is cut off, and the polyethylene glycol solution of nano-SiO2 particles is poured out. The solution can be collected and reused.

[0047] The inner and outer walls of the GH4169 alloy tube after laser shock processing are rinsed with deionized water, rinsed with ethanol, and dried to complete the processing.

[0048] Example 3

[0049] Processing target: GH4169 pipe with a wall thickness of 1.0 mm that has undergone solution treatment and double-stage aging heat treatment, with a processing length of 1.0 m.

[0050] Laser shock:

[0051] A nano-SiO2-polyethylene glycol solution, comprising 66% of the total volume of the alloy tube, is introduced into the GH4169 tube. The nano-SiO2 particles in the solution have a size in the range of 150 nm, and the mass ratio of SiO2 particles to polyethylene glycol is 0.9. The two ends of the alloy tube are sealed by welding, and the sealed alloy tube is heated to 300°C by induction heating.

[0052] Laser shock treatment was performed on the outer surface of the GH4169 alloy tube at 300℃. The laser energy was 80 mJ, the wavelength was 532 nm, the pulse width was 11 ns, the spot diameter was 0.3 mm, and the spot overlap rate was 50%. During the processing, deionized water was kept flowing on the outer surface of the tube to cover the laser spot processing area. The temperature of the deionized water outside the tube was between room temperature and 50℃. The laser shock uniformly covered the outer surface of the alloy tube, and the shock was repeated 3-5 times to ensure the uniformity of the shock processing.

[0053] After laser shock is completed, and the alloy tube is cooled to 100℃-120℃, a 2cm-5cm section of the sealed ends is cut off, and the polyethylene glycol solution of nano-SiO2 particles is poured out. The solution can be collected and reused.

[0054] The inner and outer walls of the GH4169 alloy tube after laser shock processing are rinsed with deionized water, rinsed with ethanol, and dried to complete the processing.

[0055] Example 4

[0056] Processing object: Nickel-based alloy sheet.

[0057] Laser shock treatment was performed on the surface of a nickel-based alloy sheet at 300℃. The laser energy was 70 mJ, the wavelength was 532 nm, the pulse width was 14 ns, the spot diameter was 0.3 mm, and the spot overlap rate was 50%. Deionized water was kept flowing over the sheet during the process, covering the laser-treated area. The temperature of the deionized water on the sheet surface ranged from room temperature to 50℃. The laser shock was applied evenly to the sheet surface, and the treatment was repeated 3-5 times to ensure uniformity.

[0058] The surface of the plate after laser shock processing is rinsed with deionized water, rinsed with ethanol, and dried to complete the processing.

[0059] Comparative Example 1

[0060] The preparation steps are the same as in Example 1, except that the number of laser shocks is 6.

[0061] Tests showed that after six laser shocks, the radiation resistance of the nickel-based alloy was essentially the same as after five laser shocks.

[0062] Comparative Example 2

[0063] The preparation steps are the same as in Example 1, except that the number of laser shocks is 2.

[0064] Tests showed that after two laser shocks, a uniform strengthening layer could not be formed due to insufficient shock treatment. Under irradiation, the uneven strengthening layer would result in uneven suppression of precipitate dissolution and dislocation ring nucleation, ultimately leading to a negligible improvement in the radiation resistance of the nickel-based alloy. In fact, the unevenness could even cause cracks to preferentially initiate at stress concentration sites, reducing the material's radiation resistance.

[0065] Comparative Example 3

[0066] The preparation steps are the same as in Example 2, except that the laser energy is 1000 mJ.

[0067] Testing revealed that at a laser energy of 1000 mJ, the excessively high laser power density caused significant ablation and even microcracks on the surface of the alloy tubing. This excessive energy input not only damaged the integrity of the tubing surface but also introduced a thermal damage zone near the surface. Under irradiation, these defects introduced by over-processing become preferential sites for the rapid nucleation and growth of dislocation loops, ultimately leading to a severe decline in the radiation resistance of the nickel-based alloy.

[0068] Comparative Example 4

[0069] The preparation steps are the same as in Example 2, except that the laser energy is 10 mJ.

[0070] Tests showed that when the laser energy was 10 mJ, the shock wave pressure was insufficient to generate a sufficiently concentrated dislocation network structure inside the alloy, producing only an extremely weak stress field on the alloy surface.

[0071] This application finds that the stress field alone cannot significantly inhibit the dissolution of precipitates and the growth of dislocation rings after irradiation. Irradiation-induced point defects can still freely migrate and aggregate, leading to the dissolution and diffusion of precipitates and the nucleation and growth of dislocation rings. Therefore, excessively low laser energy results in minimal improvement in radiation resistance.

[0072] Comparative Example 5

[0073] The preparation steps are the same as in Example 1, except that no solution is introduced into the GH4169 tube and laser impact is performed directly.

[0074] In the comparative example, the pipe underwent significant deformation after laser shock. Due to the lack of support and buffering effect from the internal solution, the laser shock wave was strongly reflected from the inner wall of the alloy pipe. The reflected shock wave generated tensile waves, which, combined with subsequent shock waves, caused stress superposition, resulting in overall deformation of the pipe and severely damaging its geometric accuracy.

[0075] Comparative Example 6

[0076] The preparation steps are the same as in Example 1, except that the amount of nano-SiO2-polyethylene glycol solution introduced is 95% of the internal capacity of the GH4169 pipe.

[0077] After laser shock, the pipes in the comparative example bulged and even broke. Under high temperature, the excessive liquid volume inside the pipe caused excessive pressure, leading to bulging and deformation of the 0.5 mm alloy pipe. Under laser shock, the thin-walled alloy pipe experienced a brief tensile-compression cycle due to the shock wave, further aggravating the instantaneous stress and potentially causing breakage.

[0078] Comparative Example 7

[0079] The preparation steps are the same as in Example 1, except that the amount of nano-SiO2-polyethylene glycol solution introduced is 30% of the internal capacity of the GH4169 pipe.

[0080] In the comparative example, after laser shock, localized deformation occurred on the surface of the pipe. Due to insufficient internal solution capacity, it could not provide adequate support and buffering. Therefore, the laser shock wave was strongly reflected from the inner wall of the alloy pipe. The reflected shock wave generated tensile waves, which, combined with subsequent shock waves, caused stress superposition, resulting in overall deformation of the pipe and severely compromising its dimensional accuracy.

[0081] Test case

[0082] Radiation resistance tests were conducted on the GH4169 pipes before and after laser shock in Example 1:

[0083] The alloy tube of Example 1 was irradiated with Fe ions at 450°C with an irradiation dose of 20 dpa. The microstructure and nanohardness of the irradiated alloy tube were characterized. Compared with the unprocessed initial state alloy tube, the irradiation-induced dissolution rate of the precipitated phase decreased by 40.7%, the size of the irradiated dislocation ring decreased by more than 5%, the density decreased by nearly 30%, and the change in macroscopic hardness ΔH of the alloy tube decreased by 26.7% compared with the untreated laser-shocked GH4169 alloy tube, indicating a significant improvement in radiation resistance.

[0084] like Figure 1 As shown, the average grain size of the alloy tube cross-section in the initial state was 28.30 μm, while the average grain size after five laser shock treatments was 27.26 μm. The results indicate that five laser shock treatments do not significantly refine the grain size of the material. Compared to the initial state alloy tube, the alloy tube treated with five laser shocks exhibits a wider range of residual plastic strain, mainly concentrated near grain boundaries and twin boundaries.

[0085] Figure 2 In the figures, (a) is a transmission electron microscope (TEM) image of GH4169 alloy before laser shock strengthening, showing a long strip-shaped γ'' phase; (b) is a TEM image of GH4169 alloy after laser shock strengthening, showing the dissolution of the long strip-shaped γ'' phase; (c) is a TEM image of GH4169 alloy after five laser shock strengthenings, showing the suppression of irradiation dissolution of the long strip-shaped γ'' phase; (df) the selected area electron diffraction spots at the location of the long strip-shaped γ'' phase in the figure confirm that the phase is the γ'' phase.

[0086] like Figure 2 , Figure 3 As shown, after irradiation, the size and density of the γ'' phase in the initial state of the alloy tube decreased from 277 nm to 7.4 μm. -2Reduced to 208nm and 5.9μm -2 The results showed that irradiation caused the dissolution of the γ'' phase. The shrinkage of the irradiated precipitates in the alloy tube after five laser shocks was reduced. Here, the γ'' phase is approximated as a cylinder, and its dissolution degree is quantified by the change in the volume of the γ'' phase with the irradiation dose. Compared to the initial state of the alloy tube, the dissolution rate of the precipitates in the alloy tube after five laser shocks decreased by approximately 40.7%. This result indicates that laser shock treatment significantly improves the irradiation stability of the precipitates.

[0087] Figure 4 (a1) Rel-rod transmission electron microscopy (TEM) image of GH4169 alloy after irradiation without laser shock strengthening, observed under the conditions of positive band axis =

[011] and g vector = 3-11, showing irradiated dislocation loops (long, bright spots in the image); (a2) Diffraction spot under Rel-rod conditions; (b1) Rel-rod TEM image of GH4169 alloy after five laser shock strengthenings, observed under the same conditions as a1, showing inhibition of irradiated dislocation loop growth; (b2) Diffraction spot under Rel-rod conditions; (c1) GH4169 alloy without laser shock strengthening. (c1) Rel-rod transmission electron microscope image of GH4169 alloy after irradiation, with observation conditions of positive band axis =

[011] and g vector = 31-1, irradiated dislocation rings can be observed (long strip-shaped bright spots in the image); (c2) Diffraction spot under Rel-rod conditions; (d1) Rel-rod transmission electron microscope image of GH4169 alloy after five laser shock strengthening, with observation conditions the same as c1, irradiated dislocation ring growth inhibition can be observed; (d2) Diffraction spot under Rel-rod conditions; (e) Statistical results of dislocation ring density in AD image; (f) Statistical results of dislocation ring length in AD image.

[0088] like Figure 4 As shown, the total density of irradiated dislocation loops in the initial state alloy tube is estimated to be 2.5 × 10⁻⁶. 22 m -3 In contrast, the ring density in the alloy tube after five laser shock treatments was significantly reduced to 1.76 × 10⁻⁶. 22 m -3 The reduction was approximately 30%. Furthermore, the average size of the irradiated dislocation rings in the alloy tube after five laser shocks (14.5 nm) was slightly smaller than that in the initial state alloy tube (14.97 nm). These results indicate that laser shock significantly improves the radiation resistance of the alloy tube.

[0089] Figure 5In the figures, (a) nanoindentation test results of all samples; (b) data results of the samples before irradiation after processing the nanoindentation data based on the Nix-Gao method; (c) data results of the samples after irradiation after processing the nanoindentation data based on the Nix-Gao method; and (d) macroscopic hardness values ​​before and after irradiation.

[0090] like Figure 5 As shown, the hardness values ​​H0 of the initial alloy tube before and after irradiation were 5.64 GPa and 5.49 GPa, respectively, while the hardness values ​​H0 of the alloy tube after five laser shock treatments were 5.93 GPa and 5.82 GPa, respectively. The results indicate that the laser shock treatment described in this application can improve the hardness of the alloy tube. However, irradiation caused a decrease in the hardness of the alloy tube before and after laser shock treatment. Notably, the hardness reduction ΔH (0.11 GPa) of the alloy tube after five laser shock treatments was lower than that of the initial alloy tube (0.15 GPa), representing a reduction of 26.7%.

[0091] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of this application. It should be noted that, for those skilled in the art, several improvements and modifications can be made to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A method of improving the irradiation resistance of a nickel-based alloy, characterized in that, include: The nickel-based alloy was subjected to laser shock at 300-350℃; The laser energy of the laser shock is 50 mJ-100 mJ, the wavelength is 532 nm, the pulse width is 8 ns-15 ns, and the spot diameter is 0.2-0.5 mm. The dislocation loop density of the nickel-based alloy after laser shock is less than 2.5x10 22 m -3 ; The density of precipitates of the nickel-based alloy after laser shocking and irradiation of 20 dpa is less than 7.4 μm -2 ; The laser impact is performed 3-5 times; The nickel-based alloy subjected to laser shock exhibits residual plastic strain.

2. The method of claim 1, wherein the nickel-base alloy is a nickel-chromium alloy. During the laser shock, deionized water is kept flowing on the surface of the nickel-based alloy.

3. A method of improving the irradiation resistance of a thin-walled nickel-base alloy tube, characterized by, include: A nano-SiO2-polyethylene glycol solution was introduced into the interior of the nickel-based alloy thin-walled tube. After welding and sealing, the nickel-based alloy thin-walled tube was subjected to laser impact at 300℃-350℃. The laser energy of the laser shock is 50 mJ-100 mJ, the wavelength is 532 nm, the pulse width is 8 ns-15 ns, and the spot diameter is 0.2-0.5 mm. The dislocation loop density of the nickel-based alloy thin-walled pipe after laser shock is less than 2.5x10 22 m -3 ; The precipitate density of the nickel-based alloy thin-walled pipe after laser shock is less than 7.4 μm after 20 dpa irradiation -2 ; The laser impact is performed 3-5 times; The nickel-based alloy after laser shock exhibits residual plastic strain; The amount of nano-SiO2-polyethylene glycol solution introduced is 55%-70% of the internal volume of the nickel-based alloy thin-walled tube.

4. The method of claim 3, wherein the nickel-base alloy thin-walled tubing is irradiated at a dose rate of 0.1 to 1 Mrad / second. The particle size of the nano-SiO2 is 100 nm-200 nm.

5. The method of claim 4, wherein the nickel-base alloy thin-walled tubing has a wall thickness of 0.030 inch or less. The mass ratio of nano-SiO2 to polyethylene glycol is 0.67-1.

22.

6. The method of claim 3, wherein the nickel-base alloy thin- walled tubing has a wall thickness of 0.030 inch or less. During the laser shock, deionized water is kept flowing on the surface of the nickel-based alloy; The laser impact is performed 3-5 times.

7. The method of claim 3, wherein the nickel-base alloy thin- walled tubing has a wall thickness of 0.030 inch or less. After laser shock is completed and the alloy tube is cooled to 100℃-120℃, the two ends are cut off and the nano-SiO2-polyethylene glycol solution is poured out.

8. A nickel-based alloy characterized in that, Prepared using the method described in claim 1 or 2; The nickel-based alloy has a dislocation loop density of less than 2.5 x 10 22 m -3 ; The nickel-based alloy has a precipitate density of less than 7.4 μm after irradiation of 20 dpa -2 .

Images