Method for inhibiting thermal treatment cracking of laser additive manufacturing nickel-based superalloy and application

Abstract

The invention provides a method for inhibiting heat treatment cracking of a laser additive manufacturing nickel-based superalloy and application, and relates to the field of metal additive manufacturing, and the method comprises the steps that before heat treatment is conducted on the laser additive manufacturing nickel-based superalloy, residual stress distribution data of a nickel-based superalloy part is obtained; the residual stress grade distribution of the nickel-based high-temperature alloy part is obtained according to the residual stress grade division standard; and according to the residual stress grades of different areas on the surface of the nickel-based superalloy part, corresponding shot blasting parameters are matched for surface mechanical shot blasting treatment. According to the method, appropriate shot blasting parameters are selected according to the size and distribution of the residual stress on the surface of the nickel-based superalloy to conduct surface mechanical shot blasting treatment on different areas of the surface of a part, surface residual compressive stress is introduced, and in combination with subsequent heat treatment such as hot isostatic pressing, solid solution and aging, macroscopic cracking is inhibited; and meanwhile, the component does not deform, and the surface roughness is not increased.

Description

Technical Field

[0001] This invention relates to a method and application for suppressing heat treatment cracking of nickel-based superalloys manufactured by laser additive manufacturing, and belongs to the field of metal additive manufacturing. Background Technology

[0002] Nickel-based superalloys with high γ´ content have higher high-temperature strength and creep resistance, and can serve for a long time in high-temperature environments above 850℃. They are widely used in hot-end components such as combustion chambers and turbine blades.

[0003] In recent years, with the rapid development of laser additive manufacturing technology, it has been widely applied to the rapid prototyping of complex hot-end components for gas turbines or aero engines. The extremely high cooling rates and rapid heating / cooling cycles in laser additive manufacturing processes lead to enormous thermal stress, making them highly susceptible to defects such as cracks and porosity. Only a few nickel-based superalloys with medium-to-low service temperatures do not crack during laser additive manufacturing, such as IN625, IN718, and Hastelloy X. However, nickel-based superalloys with high γ´ content at higher service temperatures, such as IN738LC, IN713, and CM247LC, suffer from severe cracking problems during the forming process and subsequent hot isostatic pressing or heat treatment.

[0004] Cracks in laser additive manufacturing are mainly solidification cracks, mostly microcracks, which can be suppressed or closed through printing parameter optimization, substrate preheating, and subsequent hot isostatic pressing. However, in the subsequent heat treatment of high γ´ content nickel-based superalloys manufactured by laser additive manufacturing, the large amount of γ´ precipitation leads to the coupling effect of lattice stress and residual stress formed during the printing process, resulting in severe time-induced deformation cracking (macro-cracking). Especially for complex components, the risk of cracking at stress concentration points is extremely high, leading to the direct scrapping of the component.

[0005] To address the technical problem of heat treatment cracking in additively manufactured nickel-based superalloys with high γ' content, CN114247899A and CN117840458A propose stress-relief annealing before solution heat treatment, which can mitigate the risk of cracking to some extent. However, for nickel-based superalloys such as IN738LC and CM247LC, the γ' phase begins to precipitate in large quantities above 700℃, and the stress-relief annealing temperature needs to be below the γ' phase precipitation temperature. Therefore, problems such as a small stress-relief annealing temperature window and poor stress-relief effect exist, making it difficult to solve the problem of heat treatment cracking. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and application for suppressing heat treatment cracking of nickel-based superalloys manufactured by laser additive manufacturing. By performing mechanical shot peening on the surface of the additively manufactured nickel-based superalloy with high γ´ content, the problem of easy cracking during heat treatment of nickel-based superalloys is solved.

[0007] To achieve the above objectives, the present invention is implemented using the following technical solution: In a first aspect, the present invention provides a method for suppressing heat treatment cracking of laser additive manufacturing nickel-based superalloys, comprising: before heat treatment of the laser additive manufacturing nickel-based superalloy, performing mechanical shot peening on the surface of the nickel-based superalloy part by the following steps: obtaining residual stress distribution data of the nickel-based superalloy part; obtaining the residual stress level distribution of the nickel-based superalloy part according to the residual stress level classification standard; and performing surface mechanical shot peening by matching corresponding shot peening parameters according to the residual stress level of different areas on the surface of the nickel-based superalloy part.

[0008] Furthermore, obtaining the residual stress distribution data of the nickel-based superalloy parts includes: obtaining the predicted residual stress distribution of the additively manufactured nickel-based superalloy parts by using numerical simulation based on the process parameters of laser additive manufacturing; The residual stress of a predetermined area on the surface of a nickel-based superalloy part was tested using the XRD diffraction nondestructive testing method to obtain the actual value of the residual stress in the predetermined area. Based on the expected distribution of residual stress of the nickel-based superalloy part and the actual value of the residual stress in the predetermined area, the residual stress distribution data of the nickel-based superalloy part was obtained.

[0009] Furthermore, the residual stress level classification standard is as follows: a residual stress of 850 MPa is defined as a high stress zone; a residual stress between 500 MPa and 850 MPa is defined as a medium stress zone; and a residual stress not exceeding 500 MPa is defined as a low stress zone.

[0010] Furthermore, steel shot is used for surface mechanical shot peening, with a peening distance of 100-200 mm; the shot peening energy in high-stress areas is 0.3-0.4 mmA; the shot peening energy in medium-stress areas is 0.1-0.2 mmA; and no shot peening is performed in low-stress areas.

[0011] Furthermore, the heat treatment includes one or more of hot isostatic pressing, solution treatment, and aging treatment.

[0012] Furthermore, the gas pressure of the hot isostatic pressing treatment is 120-180 MPa, the holding temperature is 1180-1245℃, the holding time is 1-6h, and the heating rate is 5-20℃ / min.

[0013] Furthermore, the solution treatment temperature is 1080-1250 ℃, the solution treatment time is 1-4 h, and the heating rate is 5-20 ℃ / min.

[0014] Furthermore, the aging temperature for the aging treatment is 750-900 ℃; the aging time is 12-48 h; and the heating rate is 5-20 ℃ / min.

[0015] In a second aspect, the present invention provides an application of the method for suppressing heat treatment cracking of nickel-based superalloys manufactured by laser additive manufacturing as described in the first aspect in the laser additive manufacturing of nickel-based superalloys with high γ´ content.

[0016] Thirdly, the present invention provides a nickel-based material prepared by the method described in the first aspect for suppressing heat treatment cracking of laser additive manufacturing nickel-based superalloys.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The method for suppressing heat treatment cracking of nickel-based superalloys manufactured by laser additive manufacturing provided by the present invention selects appropriate shot peening parameters according to the magnitude and distribution of residual stress on the surface of the nickel-based superalloy to perform surface mechanical shot peening treatment on different areas of the part surface, introduces residual compressive stress on the surface, and combines it with subsequent heat treatments such as hot isostatic pressing, solution treatment, and aging to suppress macroscopic cracking, while ensuring that the component does not deform and does not increase the surface roughness. Attached Figure Description

[0018] Figure 1 This is a flowchart of the method for suppressing heat treatment cracking in laser additive manufacturing of nickel-based superalloys provided in Embodiment 1 of the present invention; Figure 2 This is a diagram showing the residual stress distribution along the X-axis at the center position of the surface of the laser selective melting IN738LC sample in Embodiment 2 of the present invention. Figure 3 This is a diagram showing the residual stress distribution along the X-axis at the center of the surface of the IN738LC sample after surface mechanical shot peening in Example 2 of the present invention. Figure 4 This is a macroscopic photograph of the IN738LC sample after surface mechanical shot peening and heat treatment in Example 2 of the present invention. Figure 5 This is a cross-sectional scanning electron microscope image of the IN738LC sample after heat treatment following surface mechanical shot peening in Example 2 of the present invention. Figure 6 Macroscopic cracking occurred after heat treatment of the IN738LC sample prepared by laser selective melting in Example 2 of this invention; Figure 7 This is a scanning electron microscope image of the cross-section of the IN738LC sample prepared by laser selective melting in Example 2 of the present invention after heat treatment; Figure 8 This is a macroscopic photograph of the high γ´ content nickel-based superalloy sample after surface mechanical shot peening and heat treatment in Example 3 of the present invention. Figure 9 Macroscopic cracking occurred after heat treatment of the high γ´ content nickel-based superalloy sample prepared by laser selective melting in Example 3 of this invention. Detailed Implementation

[0019] The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or apparatus.

[0020] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0021] This invention provides a method for suppressing heat treatment cracking in laser additive manufacturing of nickel-based superalloys. First, the nickel-based superalloy parts prepared by laser additive manufacturing are subjected to shot peening to induce plastic deformation of the surface layer, forming a reinforcing layer of a certain thickness. Then, hot isostatic pressing or solution treatment is performed, followed by air cooling to room temperature. Finally, aging treatment is performed, followed by air cooling to room temperature. This results in the formation of high residual stress within the reinforcing layer, which can offset some of the stress when the part is subjected to load, thus obtaining a laser additive manufacturing nickel-based superalloy that suppresses heat treatment cracking.

[0022] Example 1 This embodiment takes nickel-based superalloys prepared by laser additive manufacturing technology as the research object and provides a method for suppressing heat treatment cracking of laser additive manufactured nickel-based superalloys, such as... Figure 1 As shown, it includes: Step 1: Prepare nickel-based superalloy parts using laser additive manufacturing technology.

[0023] The laser additive manufacturing technologies mentioned in this embodiment include: laser powder bed fusion (LPBF) or selective laser melting (SLM) and laser directional energy deposition (DED).

[0024] The nickel-based superalloys mentioned in this embodiment include commercial grades such as IN713, K418, GH4099, IN738LC, K438, CM247LC, and CMSX-4, as well as other nickel-based superalloys with high γ´ content.

[0025] Step 2: Obtain residual stress distribution data for nickel-based superalloy parts, including: Step 21: Based on the process parameters of laser additive manufacturing, the expected distribution of residual stress in the laser additive manufacturing nickel-based superalloy parts is obtained by numerical simulation.

[0026] In some specific embodiments, the finite element method is used to simulate the residual stress in the laser additive manufacturing process. The basic idea is to establish a thermo-mechanical coupling model based on process parameters such as laser power, scanning speed, and powder feeding amount. First, the temperature field of the molten pool is simulated, and then the generation and evolution of thermal stress are calculated based on the temperature gradient and the thermophysical properties of the material. Finally, the residual stress distribution after the part solidifies can be obtained.

[0027] Step 22: Use XRD diffraction nondestructive testing method to test the residual stress in a preset area on the surface of the nickel-based superalloy part and obtain the actual value of the residual stress in the preset area.

[0028] The XRD diffraction nondestructive testing method used in this embodiment is an analytical technique that utilizes the diffraction effect of crystals on X-rays to obtain residual stress without damaging the sample. It is prior art, and the specific process is not within the scope of this invention and will not be described further here.

[0029] Before laser additive manufacturing of nickel-based superalloy parts, key areas with high stress concentration, large gradient, and lifespan are pre-selected based on the specific shape of the target part as areas that need to be tested for residual stress using XRD diffraction non-destructive testing methods. These areas include tenons, sealing teeth, and the edges of cooling holes. This ensures that the key areas can be accurately matched with suitable mechanical shot peening parameters, effectively suppressing the occurrence of heat treatment cracking in laser additive manufacturing of nickel-based superalloys.

[0030] Step 23: Obtain residual stress distribution data for nickel-based superalloy parts based on the predicted residual stress distribution and the actual residual stress value in the preset area.

[0031] This embodiment combines the critical region measured by XRD with the remaining low gradient region of numerical simulation, reducing the number of measured points by 70-90%, ensuring accurate safety margin while effectively controlling economic costs.

[0032] In some more specific embodiments, the simulation parameters of the prediction region are also corrected based on the predicted and actual values ​​of residual stress at the measured points, so that the simulated stress field in the prediction region is closer to the actual value.

[0033] Step 3: Obtain the residual stress level distribution of nickel-based superalloy parts according to the residual stress level classification standard, and perform surface mechanical shot peening treatment by matching the corresponding shot peening parameters.

[0034] Before laser additive manufacturing of nickel-based superalloy parts, a standard for classifying residual stress levels is pre-defined: a residual stress of 850 MPa is defined as a high-stress zone; a residual stress between 500 MPa and 850 MPa is defined as a medium-stress zone; and a residual stress not exceeding 500 MPa is defined as a low-stress zone.

[0035] It is also necessary to set corresponding mechanical shot peening parameters for areas with different residual stress levels. In this embodiment, steel shot is used for mechanical shot peening, with a coverage of no more than 300% and a shot peening distance of 100-200 mm. The shot peening energy in the high stress area is 0.4 mmA; the shot peening energy in the medium stress area is 0.2 mmA; and no shot peening is performed in the low stress area.

[0036] Step 4: Perform heat treatment on the nickel-based superalloy parts after mechanical shot peening, and then cool them to room temperature.

[0037] In this embodiment, the heat treatment includes: hot isostatic pressing, solution treatment, and aging treatment.

[0038] Specifically, the gas pressure for hot isostatic pressing is 120-180 MPa, the holding temperature is 1180-1245℃, the holding time is 1-6h, the heating rate is 5-20℃ / min, and furnace cooling or gas cooling is used to reach room temperature. The specific process parameters are adjusted according to different grades.

[0039] The solution treatment temperature is 1080-1250 ℃, the solution treatment time is 1-4h, the heating rate is 5-20℃ / min, and it is cooled to room temperature by air or gas. The solution temperature and time are adjusted according to different grades.

[0040] The aging temperature is 750-900 ℃; the aging time is 12-48 h; the heating rate is 5-20℃ / min; and the temperature is cooled to room temperature by air.

[0041] In some embodiments, only one or two of these heat treatments are used.

[0042] Therefore, the method provided in this embodiment can be used in conjunction with in-situ parameter control and post-processing. In-situ parameters include: temperature field, thermal history, beam shaping, scanning strategy, etc. In addition, the shot peening material, shot peening distance, shot peening size, shot peening time and atmosphere can be adaptively adjusted according to the actual processing conditions.

[0043] Example 2 This embodiment provides an application of the method described in Embodiment 1 in suppressing heat treatment cracking of laser additive manufacturing nickel-based superalloys. In this embodiment, IN738LC nickel-based superalloy blocks prepared by selective laser melting (SLM) are used as samples for comparative experiments to highlight the effect of the mechanical shot peening technology provided in Embodiment 1 in suppressing heat treatment cracking of laser additive manufacturing nickel-based superalloys.

[0044] The sample size in this embodiment is 16 mm × 16 mm × 12 mm. The printing process parameters are: laser power 280 W, scanning speed 1200 mm / s, overlap spacing 80 μm, layer thickness 40 μm, and a 90° interlayer rotation scanning strategy. The IN738 alloy weight percentage is: 8.37 Co - 16.1 Cr - 3.45 Al - 3.48 Ti - 1.72 Mo - 2.57 W - 1.75 Ta - 0.87 Nb - 0.001 B - 0.1 C, with the balance being Ni.

[0045] Step 1: After cutting the printed IN738LC block from the substrate using wire electrical discharge machining, clean the sample surface.

[0046] Step 2: Use an XRD stress analyzer to test the residual stress on the upper surface of the sample, such as... Figure 2 As shown, the residual stress on the upper surface of the sample before shot peening ranged from 264 to 776 MPa, with a significant difference in residual stress values ​​between the two directions. The surface roughness of the sample before shot peening was measured using a surface roughness measuring instrument, and the average roughness was 14 μm.

[0047] Step 3: Based on the residual stress level in different areas of the sample's upper surface, areas with residual stress greater than 500 MPa are treated with surface mechanical shot peening at an energy of 0.3 mmA, while areas with residual stress not greater than 500 MPa are treated with surface mechanical shot peening at an energy of 0.1 mmA. The shot peening distance is 150 mm, ensuring 100% coverage of the entire sample's upper surface. Steel shot with a particle size of 1 mm is selected.

[0048] Step 4: After shot peening, residual stress on the upper surface of the sample is tested using an XRD stress tester, such as... Figure 3 As shown, the residual compressive stress on the upper surface of the sample after mechanical shot peening ranges from 628 to 684 MPa, and the difference in residual stress values ​​in the two directions is significantly reduced. The surface roughness of the sample after shot peening was then measured using a surface roughness measuring instrument, and the roughness was comparable to that before shot peening.

[0049] Step 5: The mechanically shot-peened sample is subjected to solution treatment in a vacuum heat treatment furnace, with the temperature increased from room temperature to 1200℃ at a rate of 10℃ / min, and held at that temperature for 2 hours. After the holding period, it is air-cooled to room temperature.

[0050] Step 6: The sample after the above solution treatment is subjected to aging treatment in a vacuum heat treatment furnace. The temperature is increased from room temperature to 850°C at a rate of 10°C / min and held for 24 hours. After the holding period, it is air-cooled to room temperature.

[0051] Figure 4 These are photos of IN738LC samples before and after heat treatment, showing that the surface of the samples did not crack after heat treatment. Figure 5 This is a cross-sectional scanning image of an IN738LC specimen that has undergone surface mechanical shot peening; no cracks were observed.

[0052] For comparison purposes, this embodiment provides the following four comparative examples: Comparative Example 1 The only difference between Comparative Example 1 and Example 2 is that the mechanical shot peening treatment in the third step is omitted; otherwise, they are the same. Figure 6 These are photos of the IN738LC printed sample in Comparative Example 1 before and after heat treatment. Figure 7 The image shows a cross-sectional scan of the IN738LC printed sample after heat treatment in Comparative Example 1. As can be seen from the image, the IN738LC printed sample, which omitted mechanical shot peening, showed obvious cracks on its surface after heat treatment, and the cross-sectional scan also showed obvious cracks.

[0053] Comparative Example 2 The only difference between Comparative Example 2 and Example 2 is that the mechanical shot peening in the third step was changed to hot isostatic pressing (HIP). The HIP process used a gas pressure of 155 MPa, a holding temperature of 1210°C, a holding time of 2 hours, and a heating rate controlled at 15°C / min (from room temperature). Air cooling to room temperature was used. All other steps remained the same. The resulting IN738LC nickel-based superalloy underwent heat treatment. Testing revealed that the sample exhibited significant surface cracking and obvious fissures after heat treatment.

[0054] Comparative Example 3 The only difference between Comparative Example 3 and Example 2 is that the mechanical shot peening treatment in the third step was changed to an annealing process, with a holding temperature of 680°C, a holding time of 24 hours, a heating rate controlled at 15°C / min (from room temperature), and air cooling to room temperature; the rest were the same, and the heat-treated IN738LC nickel-based superalloy was obtained. The test showed that the surface of the sample showed obvious cracks after heat treatment.

[0055] Comparative Example 4 The only difference between Comparative Example 4 and Comparative Example 2 is that the annealing process of Comparative Example 3 is added before the hot isostatic pressing process. The rest is the same. The resulting IN738LC nickel-based superalloy was heat-treated. The test showed that the surface of the sample showed obvious cracks after heat treatment.

[0056] As can be seen from the comparison between Example 2 and the four comparative examples, mechanical shot peening of the IN738LC nickel-based superalloy sample surface before heat treatment can effectively suppress cracking of the laser additive manufacturing nickel-based superalloy during heat treatment.

[0057] Example 3 In this embodiment, a high γ´ content nickel-based superalloy block was prepared using selective laser melting technology as a sample for comparative experiments to highlight the effect of the mechanical shot peening technology provided in Example 1 in suppressing hot-working cracking of laser additive manufacturing nickel-based superalloys.

[0058] The sample size in this embodiment is 16 mm × 16 mm × 12 mm. The specific printing process parameters are: laser power of 280 W, scanning speed of 1200 mm / s, overlap spacing of 80 μm, layer thickness of 40 μm, and a 90° interlayer rotation scanning strategy. The weight percentage of the high γ´ content nickel-based superalloy is: 8.13 Co - 15.6 Cr - 3.55 Al - 3.26 Ti - 1.99 Mo - 4.92 W - 4.83 Ta - 0.68 Nb - 0.01 Zr - 0.001 B - 0.056 C, with the balance being Ni.

[0059] After the printed high γ´ content nickel-based superalloy block was cut from the substrate by wire electrical discharge machining, the sample surface was cleaned.

[0060] To obtain the residual stress distribution on the surface of the high γ´ content nickel-based superalloy block, the area with residual stress greater than 500 MPa was treated with surface mechanical shot peening energy of 0.3 mmA, and the area with residual stress not greater than 500 MPa was treated with surface mechanical shot peening energy of 0.1 mmA. The shot peening distance was 150 mm, and the entire upper surface of the sample was 100% covered. Steel shot with a particle size of 1 mm was selected.

[0061] The sample after surface mechanical shot peening was subjected to solution treatment in a vacuum heat treatment furnace. The temperature was increased from room temperature to 1200℃ at a rate of 10℃ / min and held for 2 hours. After the holding period, the sample was air-cooled to room temperature.

[0062] The sample after the above solution treatment was subjected to aging treatment in a vacuum heat treatment furnace, and the temperature was increased from room temperature to 850°C at a heating rate of 10°C / min and held for 24 hours. After the holding period, it was air-cooled to room temperature.

[0063] Figure 8 The images show photographs of a high γ´ content nickel-based superalloy sample before and after heat treatment, which has undergone surface mechanical shot peening. As can be seen from the figures, the sample did not show obvious cracking after heat treatment.

[0064] For comparison, this embodiment provides the following comparative example, which differs from Example 3 only in that the mechanical shot peening treatment of the upper surface of the high γ´ content nickel-based superalloy block is omitted; otherwise, they are the same. Figure 9 The images show the high γ´ content nickel-based superalloy samples before and after heat treatment in this comparative example. As can be seen from the figures, the surface of the high γ´ content nickel-based superalloy sample that has not undergone mechanical shot peening shows obvious cracking after heat treatment.

[0065] Example 4 This embodiment provides a nickel-based material, prepared using the method described in Example 1 for suppressing heat treatment cracking in laser additive manufacturing of nickel-based superalloys.

[0066] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for suppressing heat treatment cracking in laser additive manufacturing of nickel-based superalloys, characterized in that, Before heat treatment of the nickel-based superalloy produced by laser additive manufacturing, the surface of the nickel-based superalloy parts is mechanically shot-peened using the following steps: Obtain residual stress distribution data for nickel-based superalloy parts; The residual stress level distribution of nickel-based superalloy parts was obtained according to the residual stress level classification standard. Based on the residual stress level of different areas on the surface of nickel-based superalloy parts, the corresponding shot peening parameters are matched for surface mechanical shot peening treatment.

2. The method for suppressing heat treatment cracking of laser additive manufacturing nickel-based superalloys according to claim 1, characterized in that, The data obtained on the residual stress distribution of the nickel-based superalloy parts include: Based on the process parameters of laser additive manufacturing, the predicted distribution of residual stress in additively manufactured nickel-based superalloy parts is obtained by numerical simulation. The residual stress of a predetermined area on the surface of a nickel-based superalloy part was tested by XRD diffraction nondestructive testing method to obtain the actual value of the residual stress in the predetermined area. Based on the predicted residual stress distribution of nickel-based superalloy parts and the actual residual stress values ​​in the preset areas, residual stress distribution data of nickel-based superalloy parts are obtained.

3. The method for suppressing heat treatment cracking of laser additive manufacturing nickel-based superalloys according to claim 1, characterized in that, The residual stress level classification standard is as follows: a residual stress of 850 MPa is defined as a high stress zone; a residual stress between 500 MPa and 850 MPa is defined as a medium stress zone; and a residual stress not exceeding 500 MPa is defined as a low stress zone.

4. The method for suppressing heat treatment cracking of laser additive manufacturing nickel-based superalloys according to claim 3, characterized in that, For surface mechanical shot peening, steel shot is used, and the peening distance is 100-200 mm. The shot peening energy for high-stress areas is 0.3-0.4 mmA; for medium-stress areas it is 0.1-0.2 mmA; and no shot peening is performed in low-stress areas.

5. The method for suppressing heat treatment cracking of laser additive manufacturing nickel-based superalloys according to claim 1, characterized in that, The heat treatment includes one or more of the following: hot isostatic pressing, solution treatment, and aging treatment.

6. The method for suppressing heat treatment cracking of laser additive manufacturing nickel-based superalloys according to claim 5, characterized in that, The gas pressure for the hot isostatic pressing treatment is 120-180 MPa, the holding temperature is 1180-1245℃, the holding time is 1-6h, and the heating rate is 5-20℃ / min.

7. The method for suppressing heat treatment cracking of laser additive manufacturing nickel-based superalloys according to claim 5, characterized in that, The solution treatment temperature is 1080-1250 ℃, the solution treatment time is 1-4 h, and the heating rate is 5-20 ℃ / min.

8. The method for suppressing heat treatment cracking of laser additive manufacturing nickel-based superalloys according to claim 5, characterized in that, The aging temperature for the aging treatment is 750-900 ℃; the aging time is 12-48 h; and the heating rate is 5-20 ℃ / min.

9. The method for suppressing heat treatment cracking of nickel-based superalloys manufactured by laser additive manufacturing as described in claims 1-8 is applied to the laser additive manufacturing of nickel-based superalloys with high γ´ content.

10. A nickel-based material, characterized in that, The method described in any one of claims 1-8 for suppressing heat treatment cracking in laser additive manufacturing of nickel-based superalloys is used.

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