Evaluation method for mechanical properties of additively manufactured GH4169 alloy thin-walled parts

Abstract

This application discloses a method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts, comprising the following steps: simulation part setup, part forming and placement determination, substrate selection, laser selective melting forming, post-processing, heat treatment, non-destructive testing, simulation part sampling performance testing, furnace test bar performance testing, and mechanical property correction and evaluation. This application corrects the mechanical property data of the furnace test bars using mechanical property data obtained from simulation part sampling, thereby obtaining mechanical properties closer to those of real additively manufactured GH4169 alloy thin-walled parts. This provides more realistic mechanical property data input for the strength and life assessment of additively manufactured GH4169 alloy thin-walled parts, making the strength and life assessment of additively manufactured GH4169 alloy thin-walled parts more accurate and reliable.

Description

Technical Field

[0001] This application relates to the field of mechanical property testing technology for parts, and in particular, to a method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts. Background Technology

[0002] Currently, GH4169 nickel-based superalloy is widely used in hot-end components of aero-engines, such as turboshaft engine parts, due to its excellent mechanical properties, oxidation resistance, and corrosion resistance. However, turboshaft engine parts using GH4169 nickel-based superalloy typically have complex structures, large dimensions, uneven wall thickness, and high requirements for dimensional accuracy and flow channel surface roughness. Traditional casting methods suffer from low yield rates and long production cycles. While additive manufacturing can significantly shorten the production cycle, laser selective melting (SDM) for large parts presents challenges due to complex anti-deformation support structures prone to cracking, leading to a high risk of part scrap. Currently, for SDM-formed parts similar to those with thin walls and internal cavities, the common method for obtaining mechanical properties is to print in-furnace test bars and perform mechanical property testing. However, although the printing parameters of the test bars are consistent with the parts, the test bars do not have the complex irregular structures of the parts. Different structures result in different mechanical properties after forming. Meanwhile, stress concentration does not occur during the printing process with the in-furnace test bar, and the microstructure of the test bar differs from that of the part. The microstructure of the in-furnace test bar is related to the laser scanning path, exhibiting a fish-scale morphology laterally and a laser scanning path vertically. This phenomenon will lead to corresponding differences in mechanical properties. Furthermore, the mechanical properties of parts from different batches inherently vary. If the anisotropic results obtained from in-furnace test bar testing are used to calculate the strength and life of the part, it will introduce even greater errors. Therefore, conventionally using in-furnace test bars to characterize the mechanical properties of additively manufactured thin-walled parts may lead to inaccurate assessments of the part's strength and life, resulting in a deviation between the part's design and actual application. Summary of the Invention

[0003] This application provides a method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts, in order to solve the technical problem that the use of furnace-in-the-place test bars to characterize the mechanical properties of additively manufactured thin-walled parts may lead to inaccurate evaluation of the strength and life of the parts, and cause a certain deviation between the design state of the parts and the actual application.

[0004] The technical solution adopted in this application is as follows:

[0005] A method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts, comprising the following steps:

[0006] Simulation component setup: Based on the sampling requirements, the 3D model of the GH4169 alloy thin-walled part is simplified and iteratively modified to obtain a simulation component of the real part. The simulation component retains the characteristic structure of the real part and the parts where stress concentration is likely to occur during the additive manufacturing process.

[0007] Part Forming and Placement Determination: Taking into account the structural characteristics of the parts, the part forming and placement determination considers the principles of forming difficulty, part deformation, saving machine time, and saving costs. While ensuring the forming accuracy of the parts, the addition of supports should be minimized and the addition of internal supports should be avoided to reduce the difficulty of post-processing. At the same time, the dangerous sections during part forming should be reduced, and the forming space of the equipment should be fully utilized to determine the placement method and forming direction of the simulation parts and furnace test bars.

[0008] Substrate selection: GH4169 alloy is selected as the substrate for laser selective melting forming, and the size is determined according to the part.

[0009] Laser selective melting forming: After the final three-dimensional model is converted into a two-dimensional sheet digital model file and imported into the computer, the computer controls the laser selective melting equipment to prepare simulated parts and furnace test bars on the GH4169 alloy substrate according to the determined process parameters, placement method and forming direction.

[0010] Post-processing: After the laser selective melting and forming is completed, the simulation part and the furnace test bar are cut off from the substrate. The simulation part and the furnace test bar are then subjected to powder cleaning, support removal and grinding post-processing operations to obtain the simulation part and the furnace test bar that meet the technical requirements.

[0011] Heat treatment: The simulated parts and test bars undergo solution treatment and aging treatment in the same furnace as the post-treatment parts;

[0012] Non-destructive testing: Fluorescence testing, X-ray testing, and CT testing are performed on the heat-treated simulants and furnace test bars to ensure that the simulants and furnace test bars meet the technical requirements;

[0013] Simulated component sampling performance testing: Samples in different directions are cut from different parts of simulated components from different batches of furnaces, and the samples are processed and tested, including microstructure testing, tensile property testing at different temperatures, and creep rupture testing, to obtain comprehensive performance data of the simulated components and obtain the correspondence between the structure, defects and performance of the simulated components.

[0014] Performance testing of test bars in furnace: Microstructure testing, tensile performance testing at different temperatures, and creep rupture testing are conducted on test bars in different directions from different furnace batches to obtain comprehensive performance data of the test bars in furnace.

[0015] Mechanical property correction and evaluation: The mechanical property data obtained by sampling the simulated part is used to correct the mechanical property data obtained by the furnace test bar, and the correction coefficient is obtained to correct the mechanical property data of the furnace test bar, so as to obtain the mechanical properties of the real additively manufactured GH4169 alloy thin-walled parts, and to evaluate the strength and life of the additively manufactured GH4169 alloy thin-walled parts.

[0016] Furthermore, before simplifying and modifying the 3D model of the GH4169 alloy thin-walled part according to the sampling requirements, the following steps are also included:

[0017] Raw material preparation involves analyzing the properties of GH4169 alloy raw material powder prepared by gas atomization to ensure that the physical properties of the powder, such as chemical composition, flowability, particle size, sphericity, and hollow powder ratio, meet the technical requirements for additive manufacturing powders.

[0018] Furthermore, the iterative modification of the 3D model of the GH4169 alloy thin-walled part to obtain a simulation of the real part specifically includes the following steps:

[0019] Computer simulations were performed on the 3D models before and after the modification. The manufacturing process of the auxiliary support for the parts was simulated and predicted based on the MSC Simufact Additive simulation software. The deformation state of the parts was compared between different schemes.

[0020] The optimal support scheme was determined by comparing different schemes, and the easily deformable areas and stress concentration locations of the parts were extracted based on the calculation results of the optimal printing support scheme.

[0021] Through continuous optimization and iteration of the 3D model, the support scheme and stress concentration location of the simulated part used for sampling are made similar to those of the real part, ensuring that the process parameters, placement method and forming direction used in the additive manufacturing process of the simulated part are consistent with those of the real part.

[0022] Furthermore, before laser selective melting and forming, the surface of the substrate is polished with coarse sandpaper to remove the surface oxide scale and expose a bright metal surface. After polishing with 1000# sandpaper, it is cleaned with alcohol and dried for later use.

[0023] Furthermore, the laser selective melting forming is carried out in an argon atmosphere, and the argon gas filling conforms to the requirements of GB / T 4842. The oxygen content in the equipment working chamber is controlled below 0.1%. The printing parameters are as follows: scanning direction: layered rotational scanning; laser power: 250~400W; scanning speed: 1000~1250mm / min; spot diameter: 0.08~0.12mm; layer thickness: 0.03~0.06mm.

[0024] Furthermore, the solution treatment specifically includes the following steps:

[0025] The furnace temperature was raised to (950~980)℃±10℃ at a heating rate of 10℃ / min, held at (950~980)℃±10℃ for 1 hour, and then cooled to room temperature under vacuum argon gas.

[0026] Furthermore, the timeliness processing includes the following steps:

[0027] The furnace temperature was raised to 720℃±5℃ at a heating rate of 8℃ / min and held at 720℃±5℃ for 8 hours. The furnace temperature was then lowered to 620℃±5℃ at a cooling rate of 50℃ / min and held at 620℃±5℃ for 8 hours. Finally, the furnace was cooled to room temperature under vacuum argon gas.

[0028] Furthermore, before sample processing and testing, samples in different orientations are cut from different parts of the simulated parts from different batches of furnaces. The process also includes the following steps:

[0029] Samples cut from different parts of different batches of simulated parts in different directions are first inspected by X-ray and CT to ensure that there are no defects.

[0030] Furthermore, before conducting microstructure testing, tensile property testing, and creep rupture property testing on test bars from different batches and in different orientations, the following steps are also included:

[0031] Test bars from different batches and in different directions are first inspected by X-ray and CT to ensure that there are no defects.

[0032] Compared with the prior art, this application has the following advantages:

[0033] a) Design a simulated part based on the 3D model of the real part, retain the simplified model of the real part’s characteristic structure, simulate the modified 3D model, and after iterative optimization, obtain a support scheme and stress concentration location of the simulated part that are similar to the real part, and determine the final 3D model of the simulated part.

[0034] b) By optimizing the forming process, problems such as cracking during part forming and stress-induced cracking of parts are solved. By post-processing, the problem of part deformation is solved.

[0035] c) Samples were taken from the simulated parts that retain the characteristic structure of the parts for microstructure and mechanical property testing. The anisotropy of the obtained mechanical property data was significantly reduced, and the mechanical property differences between batches of parts were small. This can more realistically reflect the mechanical properties of additively manufactured GH4169 alloy thin-walled parts. Furthermore, the correspondence between the microstructure, defects, and properties of the additively manufactured simulated parts can be obtained through the simulated parts.

[0036] d) The mechanical property data obtained by sampling the simulated parts are used to correct the mechanical property data of the furnace test bar, so as to obtain the mechanical properties that are closer to the real thin-walled parts of additively manufactured GH4169 alloy, and the strength and life assessment of additively manufactured GH4169 alloy thin-walled parts is more accurate and reliable.

[0037] In addition to the purposes, features, and advantages described above, this application has other purposes, features, and advantages. The application will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0038] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0039] Figure 1 This is a schematic flowchart of a preferred embodiment of the method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts according to this application.

[0040] Figure 2 It is a three-dimensional model of the actual part;

[0041] Figure 3 This is a front view schematic diagram of a real 3D model of the part;

[0042] Figure 4 This is a simplified three-dimensional model of the simulated component.

[0043] Figure 5 This is a simplified front view schematic diagram of the 3D model of the simulated component;

[0044] Figure 6 This is a side view of the placement and forming direction of the laser selective melting forming simulation part and the test bar in the furnace;

[0045] Figure 7 This is a top view of the placement and forming direction of the laser selective melting forming simulation part and the furnace test bar;

[0046] Figure 8 These are typical transverse microstructure images of the simulated part;

[0047] Figure 9 These are typical longitudinal microstructure images of the simulated part;

[0048] Figure 10 These are typical transverse microstructure images of test bars produced during furnace operation;

[0049] Figure 11 These are typical longitudinal microstructure images of test bars produced during furnace operation. Detailed Implementation

[0050] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0051] Reference Figure 1 A preferred embodiment of this application provides a method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts, comprising the following steps:

[0052] S1. Raw material preparation: The properties of GH4169 alloy raw material powder prepared by gas atomization method are analyzed to ensure that the physical properties of chemical composition (see Table 1), powder flowability, particle size distribution, sphericity and hollow powder ratio (see Table 2) meet the technical requirements of additive manufacturing powder.

[0053] Table 1: Chemical composition of GH4169 powder

[0054] element C Mn Si S P Cr Fe Co Wt / % 0.02～0.08 ≤0.35 ≤0.35 ≤0.015 ≤0.015 17.0-21.0 Remain ≤1.0 element Mo Ni Nb Ti Al Ta Cu Nb+Ta Wt / % 2.80-3.30 50.0-55.0 4.75-5.50 0.70-1.15 0.30-0.70 ≤0.05 ≤0.20 4.8-5.5 element Ca Mg B Pb Bi Ag / / Wt / % ≤0.01 ≤0.01 0.002～0.006 ≤0.0010 ≤0.0001 ≤0.0005 / /

[0055] Table 2: Physical properties of GH4169 powder

[0056]

[0057] Specifically, in the preferred embodiment, the chemical composition of the GH4169 powder raw material is shown in Table 3, and the physical properties of the powder are shown in Table 4.

[0058] Table 3: Chemical composition of GH4169 powder (wt.%)

[0059] element C Mn Si S P Cr Co Actual measurement 0.037 0.030 0.050 ＜0.0020 ＜0.01 19.15 0.24 element Mo Ni Nb Ti Al Ta Cu Actual measurement 3.12 52.91 5.10 1.02 0.53 ＜0.01 0.038 element Ca Mg B Pb Bi Ag Nb+Ta Actual measurement ＜0.002 ＜0.01 ＜0.005 ＜0.0001 ＜0.00001 ＜0.0001 5.12

[0060] Table 4: Physical properties of GH4169 powder

[0061]

[0062] S2. Simulation Part Setup: Based on the sampling requirements, create a 3D model of the GH4169 alloy thin-walled part (see...). Figure 2 and Figure 3 The simulation part is simplified and iteratively modified through simulation to obtain a model of the real part. This model retains the characteristic structure of the real part and areas prone to stress concentration during additive manufacturing. Specifically, this embodiment retains the part's ring structure, internal support plate, support plate rotation structure, and chamfers between the support plate and the inner and outer rings. The specific 3D model of the simulation part can be found in [link to model]. Figure 4 and Figure 5 The iterative modification of the 3D model of the GH4169 alloy thin-walled part to obtain a simulation of the actual part specifically includes the following steps:

[0063] S21. Perform computer simulation on the three-dimensional models before and after modification, and conduct simulation analysis and prediction of the auxiliary support manufacturing process of the parts based on MSC Simufact Additive simulation software, and compare the deformation state of the parts between different schemes.

[0064] S22. Determine the optimal support scheme by comparing different schemes, and extract the easily deformable areas and stress concentration locations of the parts based on the calculation results of the optimal printing support scheme.

[0065] S23. Through continuous optimization and iteration of the 3D model, the support scheme and stress concentration location of the simulated part used for sampling are made similar to those of the real part, ensuring that the process parameters, placement method and forming direction used in the additive manufacturing process of the simulated part are consistent with those of the real part.

[0066] Simulation analysis results show that both the real part and the simulated part are central support plate structures. Due to the shrinkage deformation of the rotation feature during the forming process, stress concentration occurs in the area connected to the rotation structure.

[0067] This embodiment retains the part's ring structure, internal support plate, support plate rotation structure, and chamfers between the support plate and the inner and outer rings, among other structural features. See the specific model for details. Figure 4 and Figure 5 .

[0068] S3. Part Forming and Placement Determination: The part forming and placement determination considers the structural characteristics of the part, taking into account forming difficulty, part deformation, saving machine time, and cost savings. While ensuring forming accuracy, it minimizes the addition of supports, avoids adding internal supports, and reduces post-processing difficulty. Simultaneously, it reduces dangerous sections during part forming and fully utilizes the forming space of the equipment. The placement method and forming direction of the simulation part and furnace test bar are determined, specifically as follows: Figure 6 and Figure 7 As shown, the arrows indicate the forming direction of the part. To address the issues of large laser selective melting sintering area and easy cracking of supports, solid supports are added around the part during support addition to avoid the forming risk of cracking associated with ordinary supports. Simultaneously, to address deformation and dimensional issues during post-processing, the process support scheme is optimized through iterative testing to reduce part deformation and ensure that the part dimensions meet requirements.

[0069] S4. Substrate Selection: GH4169 alloy is selected as the substrate for selective laser melting (SLM). The size is determined based on the part. In this embodiment, the size of the GH4169 alloy substrate is 600mm × 600mm × 800mm. A GH4169 high-temperature alloy simulation part and a furnace test bar are laser-precision formed (SLM) on a 600mm × 600mm plane. Before SLM, the substrate surface is sanded with coarse sandpaper to remove the oxide scale, exposing a bright metal surface. Sanding continues until 1000# sandpaper is used, followed by cleaning with alcohol and drying.

[0070] S5. Selective Laser Melting: After the finalized 3D model is converted into a 2D layered digital model file and imported into the computer, the computer controls the selective laser melting equipment to prepare simulated parts and furnace test bars on the GH4169 alloy substrate according to the determined process parameters, placement method, and forming direction. The selective laser melting is carried out in an argon atmosphere, and the argon gas filling conforms to GB / T 4842. The oxygen content in the equipment's working chamber is controlled below 0.1%. The printing parameters are as follows: Scanning direction: layered rotational scanning; Laser power: 250–400W; Scanning speed: 1000–1250mm / min; Spot diameter: 0.08–0.12mm; Layer thickness: 0.03–0.06mm.

[0071] Preferably, the laser selective melting equipment includes a 500W IPG laser, a CNC worktable, a working chamber, a water cooling system, a purification system, and an atmosphere control system. The maximum formable area has a length, width, and height of 600mm, 600mm, and 600mm, respectively. Printing parameters are set as follows: laser power: 300W; scanning speed: 1100mm / min; spot diameter: 0.10mm; layer thickness: 0.05mm; the argon gas used for filling should comply with GB / T4842, with a purity of not less than 99.99%, and the oxygen content should be confirmed as 0.05% by an oxygen analyzer. Three batches of simulated parts were formed, each batch including a furnace test bar.

[0072] S6. Post-processing: After the laser selective melting and forming is completed, the simulation part and the furnace test bar are cut off from the substrate. The simulation part and the furnace test bar are then subjected to powder cleaning, support removal and grinding post-processing operations to obtain the simulation part and the furnace test bar that meet the technical requirements.

[0073] S7. Heat Treatment: The post-processed simulated parts and furnace-accompanied test bars are subjected to solution treatment and aging treatment in the same furnace. A high-pressure gas-quenched vacuum furnace with an accuracy meeting ±5℃ and NADCAP certification is required. The simulated parts and furnace-accompanied test bars are placed together in the high-pressure gas-quenched vacuum furnace, leaving gaps between each test piece. When the vacuum level inside the furnace drops below the set value, the simulated parts and furnace-accompanied test bars undergo the following heat treatment to resolve the stress problem generated during laser selective melting and forming. Stress-relief heat treatment is performed promptly after part forming to prevent cracking due to stress. The solution treatment specifically includes the following steps:

[0074] The furnace temperature was raised to (950~980)℃±10℃ at a heating rate of 10℃ / min, held at (950~980)℃±10℃ for 1 hour, and then cooled to room temperature under vacuum argon gas.

[0075] The timeliness processing includes the following steps:

[0076] The furnace temperature was raised to 720℃±5℃ at a heating rate of 8℃ / min and held at 720℃±5℃ for 8 hours. The furnace temperature was then lowered to 620℃±5℃ at a cooling rate of 50℃ / min and held at 620℃±5℃ for 8 hours. Finally, the furnace was cooled to room temperature under vacuum argon gas.

[0077] In a preferred embodiment, the solution treatment specifically includes the following steps: raising the furnace temperature to 970°C at a heating rate of 10°C / min, holding at 970°C for 1 hour, and then cooling to room temperature under vacuum argon gas; the aging treatment includes the following steps: raising the furnace temperature to 720°C at a heating rate of 8°C / min, holding at 720°C for 8 hours, lowering the furnace temperature to 620°C at a cooling rate of 50°C / min, holding at 620°C for 8 hours, and then cooling to room temperature under vacuum argon gas.

[0078] S8. Non-destructive testing: Fluorescence testing, X-ray testing, and CT testing are performed on the heat-treated simulants and furnace test bars. Preferably, when performing fluorescence penetrant testing on the simulants and furnace test bars, the penetrant time is 10 minutes, the imaging time is 20 minutes, and a sensitivity level of 3 is used. After the surface quality meets the technical requirements, X-ray testing is performed using a micro-coke device and a Class B testing level. The X-ray testing meets the technical requirements. Then, CT testing is performed on the simulants and furnace test bars to ensure that they meet the technical requirements. After meeting the technical requirements, the next step is performed.

[0079] S9. Performance Testing of Simulated Parts: Samples in different directions are cut from different parts of simulated parts from different batches. After X-ray and CT inspection to ensure there are no defects, the samples are processed and tested, including microstructure analysis, tensile property testing at different temperatures, and creep rupture testing. Comprehensive performance data of the simulated parts are obtained, and the correspondence between the simulated part's structure, defects, and performance is derived. The results are shown in […]. Figure 8 , Figure 9 Tables 5 and 6:

[0080] Table 5: Tensile properties of simulated parts

[0081]

[0082]

[0083] Table 6: Durability of Simulated Components

[0084]

[0085] In this implementation case, the simulated specimens in different orientations had completely recrystallized, and the laser scanning paths in the microstructure disappeared completely after heat treatment, exhibiting a near-equiaxed crystal state. The differences in the transverse and longitudinal microstructures were not significant, with no obvious anisotropy. However, the furnace-bearing test bars showed significant differences in the transverse and longitudinal microstructures, and the longitudinal specimens exhibited a clear orientation along the deposition direction. The mechanical properties obtained from the simulated specimens were basically equivalent in the transverse and longitudinal directions, and the anisotropy of the mechanical properties of each specimen was significantly reduced.

[0086] S10. Performance Testing of In-Furnace Test Bars: In-furnace test bars from different batches and in different orientations are first inspected by X-ray and CT scans to ensure there are no defects. Then, microstructure testing, tensile property testing, and creep rupture property testing are performed to obtain comprehensive performance data for the test bars. Results are shown in […]. Figure 10 , Figure 11 Tables 7 and 8.

[0087] Table 7: Tensile properties of test bars tested in the furnace

[0088]

[0089] Table 8: Creep performance of test bars in furnace

[0090]

[0091] It is evident that the transverse tensile properties of the furnace-tested bars are significantly better than those of the longitudinal specimens, while the longitudinal specimens exhibit significantly better creep properties than the transverse specimens, demonstrating anisotropy. Furthermore, although the mechanical properties of the simulated parts vary between each batch, this variation is significantly smaller than that of the furnace-tested bars from different batches.

[0092] S11. Mechanical property correction and evaluation: The mechanical property data obtained by sampling the simulated part is used to correct the mechanical property data obtained by the furnace test bar, and the correction coefficient is obtained to correct the mechanical property data of the furnace test bar, so as to obtain the mechanical properties of the real additively manufactured GH4169 alloy thin-walled parts, and to evaluate the strength and life of the additively manufactured GH4169 alloy thin-walled parts, thereby improving the accuracy of the strength and life evaluation.

[0093] This application focuses on additively manufactured GH4169 alloy thin-walled parts and provides a method for evaluating the mechanical properties of these parts. This method addresses the difficulty of sampling the thin-walled parts for mechanical property testing and the anisotropy issues associated with using test bars from the same furnace for mechanical property testing. It designs a simulated part that retains the characteristic structure of the part. Samples are taken from this simulated part, which has undergone overall heat treatment, to examine its microstructure and perform mechanical property testing. This yields a microstructure and mechanical properties that more closely resemble those of the real part, providing more accurate and reliable mechanical property data input for strength and life assessment of additively manufactured GH4169 alloy thin-walled parts.

[0094] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0095] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts, characterized in that, Including the following steps: Simulation component setup: Based on the sampling requirements, the 3D model of the GH4169 alloy thin-walled part is simplified and iteratively modified to obtain a simulation component of the real part. The simulation component retains the characteristic structure of the real part and the parts where stress concentration is likely to occur during the additive manufacturing process. Part Forming and Placement Determination: Taking into account the structural characteristics of the parts, the part forming and placement determination considers the principles of forming difficulty, part deformation, saving machine time, and saving costs. While ensuring the forming accuracy of the parts, the addition of supports should be minimized and the addition of internal supports should be avoided to reduce the difficulty of post-processing. At the same time, the dangerous sections during part forming should be reduced, and the forming space of the equipment should be fully utilized to determine the placement method and forming direction of the simulation parts and furnace test bars. Substrate selection: GH4169 alloy is selected as the substrate for laser selective melting forming, and the size is determined according to the part. Laser selective melting forming: After the final three-dimensional model is converted into a two-dimensional sheet digital model file and imported into the computer, the computer controls the laser selective melting equipment to prepare simulated parts and furnace test bars on the GH4169 alloy substrate according to the determined process parameters, placement method and forming direction. Post-processing: After the laser selective melting and forming is completed, the simulation part and the furnace test bar are cut off from the substrate. The simulation part and the furnace test bar are then subjected to powder cleaning, support removal and grinding post-processing operations to obtain the simulation part and the furnace test bar that meet the technical requirements. Heat treatment: The post-treatment simulation parts and the test bars were subjected to solution treatment and aging treatment in the same furnace; Non-destructive testing: Fluorescence testing, X-ray testing, and CT testing are performed on the heat-treated simulants and furnace test bars to ensure that the simulants and furnace test bars meet the technical requirements; Simulated component sampling performance testing: Samples in different directions are cut from different parts of simulated components from different batches of furnaces, and the samples are processed and tested, including microstructure testing, tensile property testing at different temperatures, and creep rupture testing, to obtain comprehensive performance data of the simulated components and obtain the correspondence between the structure, defects and performance of the simulated components. Performance testing of test bars in furnace: Microstructure testing, tensile performance testing at different temperatures, and creep rupture testing are conducted on test bars in different directions from different furnace batches to obtain comprehensive performance data of the test bars in furnace. Mechanical property correction and evaluation: The mechanical property data obtained by sampling the simulated part is used to correct the mechanical property data obtained by the furnace test bar, and the correction coefficient is obtained to correct the mechanical property data of the furnace test bar, so as to obtain the mechanical properties of the real additively manufactured GH4169 alloy thin-walled parts, and to evaluate the strength and life of the additively manufactured GH4169 alloy thin-walled parts.

2. The method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts according to claim 1, characterized in that, Before simplifying and modifying the 3D model of the GH4169 alloy thin-walled part according to the sampling requirements, the following steps are also included: Raw material preparation involves analyzing the properties of GH4169 alloy raw material powder prepared by gas atomization to ensure that the physical properties of the powder, such as chemical composition, flowability, particle size, sphericity, and hollow powder ratio, meet the technical requirements for additive manufacturing powders.

3. The method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts according to claim 1, characterized in that, The process of iteratively modifying the 3D model of the GH4169 alloy thin-walled part to obtain a simulation of the actual part specifically includes the following steps: Computer simulations were performed on the 3D models before and after the modification. The manufacturing process of the auxiliary support for the parts was simulated and predicted based on the MSC Simufact Additive simulation software. The deformation state of the parts was compared between different schemes. The optimal support scheme was determined by comparing different schemes, and the easily deformable areas and stress concentration locations of the parts were extracted based on the calculation results of the optimal printing support scheme. Through continuous optimization and iteration of the 3D model, the support scheme and stress concentration location of the simulated part used for sampling are made similar to those of the real part, ensuring that the process parameters, placement method and forming direction used in the additive manufacturing process of the simulated part are consistent with those of the real part.

4. The method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts according to claim 1, characterized in that, Before laser selective melting and forming, the surface of the substrate is sanded with coarse sandpaper to remove the surface oxide scale and expose a bright metal surface. After sanding with 1000# sandpaper, it is cleaned with alcohol and dried for later use.

5. The method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts according to claim 1, characterized in that, Laser selective melting and forming is performed in an argon atmosphere, with the argon gas conforming to GB / T 4842. The oxygen content in the equipment's working chamber is controlled below 0.1%. The printing parameters are as follows: scanning direction: layered rotary scanning; laser power: 250–400W; scanning speed: 1000–1250 mm / min; spot diameter: 0.08–0.12 mm; layer thickness: 0.03–0.06 mm.

6. The method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts according to claim 1, characterized in that, The solution treatment specifically includes the following steps: The furnace temperature was raised to (950~980)℃±10℃ at a heating rate of 10℃ / min, held at (950~980)℃±10℃ for 1 hour, and then cooled to room temperature under vacuum argon gas.

7. The method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts according to claim 1, characterized in that, The timeliness processing includes the following steps: The furnace temperature was raised to 720℃±5℃ at a heating rate of 8℃ / min and held at 720℃±5℃ for 8 hours. The furnace temperature was then lowered to 620℃±5℃ at a cooling rate of 50℃ / min and held at 620℃±5℃ for 8 hours. Finally, the furnace was cooled to room temperature under vacuum argon gas.

8. The method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts according to claim 1, characterized in that, Before sample processing and testing, samples are cut from different parts of different batches of simulated parts in different directions. The process also includes the following steps: Samples cut from different parts of different batches of simulated parts in different directions are first inspected by X-ray and CT to ensure that there are no defects.

9. The method for evaluating the mechanical properties of additively manufactured GH4169 alloy thin-walled parts according to claim 1, characterized in that, Before performing microstructure analysis, tensile property testing, and creep rupture property testing on furnace-batch test bars of different orientations, the following steps are also included: Test bars from different batches and in different directions are first inspected by X-ray and CT to ensure that there are no defects.

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