A process method for eliminating printing cracking of GH3230 composite powder

Abstract

This application relates to the field of metal additive manufacturing, and in particular to a process method for eliminating printing cracks using GH3230 composite powder, characterized by the following steps: S1: preparing basic GH3230 powder, adding a crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment to obtain composite powder; S2: using SLM printing technology to print the composite powder to obtain a printed component; S3: performing post-printing heat treatment on the printed component, which improves upon the existing technology's difficulty in effectively suppressing microcracks in GH3230 alloy SLM forming while maintaining the material's original high-temperature oxidation resistance and mechanical stability.

Description

Technical Field

[0001] This application relates to the field of metal additive manufacturing, and in particular to a process method for eliminating printing cracks using GH3230 composite powder. Background Technology

[0002] With the increasing demand for complex structural components in high-end equipment, surface-mount metal (SLM) printing technology, as a typical powder-layout metal additive manufacturing technology, has become an ideal choice for processing complex GH3230 alloy components due to its advantages such as flexible forming, rapid response, and unrestricted forming structures. Compared with traditional casting, forging, and milling processes, it can significantly shorten the R&D cycle and reduce processing costs. However, in practical applications, it has been found that even under optimized SLM process parameters, the formed GH3230 alloy components still generally have a large number of microcracks. The formation of these microcracks is closely related to the solidification characteristics of GH3230 alloy and the coupling effect of thermal stress and strain during the SLM forming process, and cannot be effectively reduced by simply adjusting process parameters such as laser power and scanning speed.

[0003] Currently, some existing technologies have attempted to address the cracking problem in SLM forming of GH3230 alloy by adding ceramic particles. While this can reduce cracks to some extent, ceramic particles have low thermal conductivity, and excessive addition can lead to insufficient powder melting, resulting in new crack defects. Furthermore, the compatibility between ceramic particles and the metal matrix is ​​limited, which can easily cause interfacial stress concentration.

[0004] Regarding the aforementioned technologies, the inventors believe that existing technologies are insufficient to effectively suppress microcracks in the SLM forming of GH3230 alloy while simultaneously maintaining the material's original high-temperature oxidation resistance and mechanical stability. Summary of the Invention

[0005] To address the limitations of existing technologies in effectively suppressing microcracks during SLM forming of GH3230 alloy while maintaining the material's original high-temperature oxidation resistance and mechanical stability, this application provides a process method for eliminating printing cracks using GH3230 composite powder, characterized by the following steps: S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; S2: The composite powder is printed using SLM printing technology to obtain a printed component; S3: Perform post-forming heat treatment on the printed component; The crack-suppressing dopant phase is selected from one or more of molybdenum powder, niobium powder, and tungsten powder; wherein, when only molybdenum powder is used as the crack-suppressing dopant phase, the mass of molybdenum powder is 0.2-2.0% of the mass of the base GH3230 powder; when only niobium powder is used as the crack-suppressing dopant phase, the mass of niobium powder is 0.2-1.5% of the mass of the base GH3230 powder; when only tungsten powder is used as the crack-suppressing dopant phase, the mass of tungsten powder is 0.2-2.5% of the mass of the base GH3230 powder; when the crack-suppressing dopant phase is a composite addition or a combination of the above three powders, the total added mass is 0.2-2.5% of the mass of the base GH3230 powder.

[0006] By adopting the above technical solution, and adding a specific proportion of molybdenum powder, niobium powder, or tungsten powder to the base GH3230 powder as crack-suppressing dopant phases, the solidification structure of the alloy can be refined and the solidification rate can be adjusted. This effectively alleviates the thermal stress concentration during SLM forming and inhibits the precipitation of brittle phases and grain boundary embrittlement, thus improving the situation where a large number of microcracks are commonly found in traditional SLM-formed GH3230 alloy components. By using molybdenum, niobium, and tungsten as high-strength metal elements for composite doping in specific proportions, and combining this with post-printing heat treatment, not only are stress concentration points caused by crack defects effectively reduced, but the matrix structure is further optimized through the solid solution strengthening effect of the elements. This significantly improves the room temperature microhardness, yield strength, tensile strength, and elongation of the printed components, thus improving the weak load-bearing capacity and easy fracture failure of components formed by traditional undoped processes.

[0007] Preferably, the basic GH3230 powder in step S1 comprises, by mass fraction: C 0.05%-0.15%, Cr 20%-24%, Co 1%-5%, W 13%-15%, Mo 1%-3%, Al 0.2%-0.5%, Ti 0.01%-0.1%, Fe 0.01%-3%, La 0.005%-0.05%, B 0.01%-0.015%, Si 0.25%-0.75%, Mn 0.3%-1%, with the balance being Ni and unavoidable impurities.

[0008] Preferably, the particle size distribution of the composite powder in step S1 is 15-53 μm, and the average particle size of the molybdenum powder, niobium powder and tungsten powder is less than 5 μm.

[0009] By adopting the above technical solution, the particle size of the basic GH3230 powder is controlled within the range of 15-53μm, and micro-nano grade molybdenum powder, niobium powder and tungsten powder with an average particle size of less than 5μm are used in combination. This allows the fine doped powder to uniformly coat and adhere to the surface of the larger basic powder, reducing the agglomeration of high melting point doped metal powder, while ensuring the overall high fluidity and dense powder spreading of the composite powder.

[0010] Preferably, the method for preparing the basic GH3230 powder in step S1 is any one of vacuum induction melting gas atomization process, electrode induction melting gas atomization process, and plasma rotating electrode process.

[0011] By adopting the above technical solutions and using advanced powder preparation processes such as vacuum induction melting gas atomization, electrode induction melting gas atomization, or plasma rotating electrode to prepare basic alloy powders, the oxygen content and impurities inside the powder can be effectively controlled, resulting in basic metal powders with high sphericity, density, and excellent flowability.

[0012] Preferably, in step S1, the specific method of the mixing pretreatment is as follows: The basic GH3230 powder, molybdenum powder, niobium powder, and tungsten powder are placed in a vacuum drying oven at 80-120℃ and dried for 1-3 hours to remove the moisture and oil adsorbed on the powder surface and prevent porosity defects during the forming process. The powder was mixed using a high-speed mixer at a speed of 1300-1700 rpm. Each mixing session lasted 1-1.5 minutes. After mixing, the powder was cooled for 15-25 minutes. The mixing process was repeated 2-3 times until the powder was uniformly mixed and there was no obvious agglomeration. The final product was GH3230-Mo, GH3230-Nb, or GH3230-W single-doped composite powder, or GH3230-Mo-Nb-W mixed-doped composite powder.

[0013] By adopting the above technical solution, using vacuum drying at specific temperatures and times, and combining it with a high-speed mixing process with specific rotation speeds, short cycles, and cooling gaps, heat accumulation and powder agglomeration during the mixing process are reduced, ensuring that the fine crack-suppressing dopant phase is uniformly dispersed and adheres to the surface of the base powder.

[0014] Preferably, in step S2, the process parameters of the SLM printing forming technology are: laser power 170-310W, scanning speed 650-1050mm / s, powder layer thickness 30-70μm, scanning spacing 70-130μm, scanning strategy is bidirectional staggered scanning, and the interlayer scanning angle is deflected by 60°; argon gas protection is used during the forming process, and the oxygen content is controlled below 0.1%.

[0015] Preferably, the printed component is subjected to hot isostatic pressing at a temperature of 1080-1200℃ and a pressure of 160±10MPa for 1-5 hours, followed by solution strengthening treatment, in which the temperature is increased to 1160-1200℃ at a rate of 8-12℃ / min and held for 1-4 hours to ensure that the alloying elements are fully dissolved and to eliminate microstructure segregation; then argon gas is used for forced cooling.

[0016] Preferably, the vacuum induction furnace body is evacuated to 10... -2 -10 -3 The GH3230 raw material alloy is placed in a crucible and heated to 1540-1570 ℃ by medium-frequency induction heating. It is then held at this temperature for 5-20 minutes for refining. After the gas filling is completed, the temperature is lowered to 1400-1450 ℃. The molten metal flows into the atomizing nozzle through the bottom guide hole of the heat-insulating intermediate ladle. High-pressure argon gas of 3-6 MPa is introduced into the atomizing nozzle. The gas flow and the molten metal flow converge, breaking them into fine droplets of 10-150 μm. The droplets form spherical shapes due to surface tension during their fall. They are then rapidly cooled in an inert atmosphere. The powder is classified by a cyclone separator and falls into a collection tank. After cooling to room temperature, it is taken out and sieved to obtain basic GH3230 powder that meets the particle size specifications for laser additive manufacturing.

[0017] Preferably, the electrode induction melting gas atomization process includes the following steps: evacuating the vacuum induction furnace to 10... -2 -10 -3 Under a protective atmosphere of 0.05-0.1 MPa, high-purity argon gas is introduced. A consumable electrode made from a GH3230 master alloy rod is clamped in a lifting and rotating mechanism and fed into a ring-shaped induction coil inside the furnace. Medium-frequency induction heating causes the electrode tip to consumable melt to 1540-1570 ℃. The electrode is held at this temperature for 5-20 minutes for refining. The heating power is adjusted to stabilize the molten pool temperature within the range required for atomization. The electrode descent rate is adjusted to form a stable droplet beam of molten metal, which falls vertically into the atomizing nozzle. High-pressure argon gas of 3-6 MPa is introduced into the atomizing nozzle. The gas flow converges with the molten metal droplet beam, breaking it into fine droplets of 10-150 μm. The powder is rapidly cooled in an inert atmosphere. After being classified by a cyclone separator, the powder falls into a collection tank, cools to room temperature, and is then sieved to obtain basic GH3230 powder conforming to the particle size specifications for laser additive manufacturing.

[0018] Preferably, the plasma rotating electrode process includes the following steps: The vacuum induction furnace body is evacuated to 10. -2 -10 -3A protective atmosphere of 0.05-0.1 MPa is established by filling the atmosphere with high-purity argon gas. The GH3230 master alloy rod is made into an electrode and clamped onto the high-speed rotating spindle of the equipment. The electrode tip is heated by plasma arc focusing to melt it to 1540-1570 ℃. The electrode is then held at this temperature for 5-20 minutes for refining. The plasma power is adjusted to make the temperature of the melting area at the electrode tip suitable for atomization. The plasma power and electrode rotation speed are adjusted so that the molten metal is thrown out under centrifugal force to form fine droplets of 10-150 μm. The droplets form spherical shapes due to surface tension during their fall. The powder is then rapidly cooled in an inert atmosphere. The powder is separated by a sedimentation and grading device and falls into a collection tank. After cooling to room temperature, the powder is removed and sieved to obtain basic GH3230 powder that meets the particle size specifications for additive manufacturing.

[0019] In summary, this application includes at least one of the following beneficial technical effects: Molybdenum powder, niobium powder, and tungsten powder have excellent compatibility with the GH3230 alloy matrix. They can effectively alleviate the thermal stress concentration during the SLM forming process by refining the solidification structure and adjusting the solidification rate of the alloy. At the same time, they can inhibit the precipitation of brittle phases and grain boundary embrittlement, thus improving the occurrence of hot cracks and strain aging cracks. Molybdenum, niobium, and tungsten, as high-strength metallic elements, can not only enhance the strength of the alloy matrix through solid solution strengthening, but also reduce stress concentration points by eliminating crack defects, thus greatly enhancing the load-bearing capacity of components. The addition of molybdenum powder, niobium powder, and tungsten powder does not change the solid solution strengthening system of GH3230 alloy. The components still maintain a wide temperature range of 700~1050℃. Their high-temperature oxidation resistance and thermal stability are comparable to those of pure GH3230 undoped printed alloy, which can meet the high-temperature service requirements of aerospace and other fields. This technology improves upon existing techniques that struggle to effectively suppress microcracks in the SLM forming of GH3230 alloy while maintaining the material's original high-temperature oxidation resistance and mechanical stability. Attached Figure Description

[0020] Figure 1 This is a scanning electron microscope image of the microstructure of the crack suppression doped phase used in Example 1 of this application.

[0021] Figure 2 This is a scanning electron microscope image of the microstructure of GH3230 composite powder obtained by mixing and pretreating basic GH3230 powder and molybdenum powder in Example 1 of this application.

[0022] Figure 3 This is a scanning electron microscope image of the cross-sectional microstructure of a pure GH3230 printout prepared without doping and powder mixing process in Comparative Example 1 of this application after heat treatment.

[0023] Figure 4The printed part was prepared using GH3230 composite powder. The cross-sectional microstructure of the part after heat treatment after forming shows that the microcracks were effectively suppressed and the structure was dense.

[0024] Figure 5 This is a scanning electron microscope (SEM) image of the room-temperature tensile fracture morphology of the pure GH3230 printed part prepared without doping and powder mixing process in Comparative Example 2 of this application.

[0025] Figure 6 This is a scanning electron microscope image of the room temperature tensile fracture morphology of the printed part prepared by the niobium powder doping and mixing process in Example 2 of this application.

[0026] Figure 7 This is an energy dispersive electron microscope (EDS) image of a printed part prepared by a tungsten powder doping and mixing process after heat treatment.

[0027] Figure 8 This is an energy dispersive electron microscope (EDS) image of a printed part prepared by a mixed doping process of molybdenum powder, niobium powder, and tungsten powder after heat treatment. Detailed Implementation

[0028] The following is in conjunction with the appendix Figure 1-8 This application will be described in further detail.

[0029] This application discloses a process method for eliminating printing cracks using GH3230 composite powder.

[0030] Performance testing adopts the tensile yield test standard: room temperature GB / T 228.1-2021, high temperature GB / T 228.2-2021 and "Metallic materials, tensile testing - Part 1: room temperature test method".

[0031] The basic raw materials include: 305 alloy, metallic chromium, Jinchuan cobalt, tungsten bars, molybdenum bars, pure iron, pure aluminum, 301 alloy, and Jinchuan nickel.

[0032] Example 1

[0033] S1 prepares basic GH3230 powder, adds crack-inhibiting dopant phase to basic GH3230 powder for mixing and pretreatment, and obtains composite powder; Basic GH3230 powder preparation adopts vacuum induction melting gas atomization process: Raw material smelting: Vacuuming to 5×10 -3 Pa, fill with high-purity argon gas to a protective atmosphere of 0.07 MPa, place the basic component raw materials in a vacuum induction furnace, then raise the temperature to 1550 ℃ at a rate of 7 ℃ / min, and hold for 18 minutes for refining.

[0034] Atomization powder preparation: The atomizing tank is purged with argon twice, the atomization pressure is controlled at 3.6 MPa, and after the purging is completed, the temperature is reduced to 1430℃. The molten metal flows into the atomizing nozzle through the bottom guide hole of the heat-insulated intermediate tank. The outlet temperature of the molten metal is 1430℃. The nozzle is preheated to 320℃. High-pressure argon gas of 4.5 MPa is introduced into the atomizing nozzle. The gas flow and the molten metal flow converge and break into fine droplets of 10~150 μm. The droplets form spherical shapes due to surface tension during the falling process. They are rapidly cooled in an inert atmosphere. The powder is classified by a cyclone separator and falls into a collection tank. After cooling to room temperature, it is taken out to obtain the initial powder.

[0035] Powder sieving: After ultrasonic vibration sieving, basic powder with a particle size distribution of 15~53 μm was obtained, with a Hall flow rate of 14.5 s / 50g and a sphericity of 0.93.

[0036] Basic powder formulation and pretreatment: The GH3230 powder composition by mass fraction includes: C 0.07%, Cr 21.8%, Co 2.8%, W 13.8%, Mo 1.8%, Al 0.32%, Ti 0.05%, Fe 1.8%, La 0.018%, B 0.009%, Si 0.42%, Mn 0.55%, with the balance being Ni and unavoidable trace impurities. The powder was dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0037] Doping powder ratio and pretreatment: Molybdenum powder with a purity ≥99.9% and an average particle size of 3 μm was selected, and the mass of the molybdenum powder was 0.7% of the mass of the base GH3230 powder. The powders were dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0038] Composite powder preparation: The mixture was prepared by mixing with a high-speed mixer at 1400 rpm for 1 minute each time. After cooling for 18 minutes, the mixing was repeated twice. The uniformity of the mixture was ≥94% to obtain the composite powder.

[0039] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing process: The core process parameters are adjusted to: laser power 180 W, scanning speed 750 mm / s, powder layer thickness 38 μm, scanning spacing 105 μm, scanning strategy is bidirectional staggered scanning, and the oxygen content in the printing chamber is controlled below 0.08%.

[0040] S3: Perform post-forming heat treatment on the printed component; Post-forming heat treatment: First, hot isostatic pressing is performed at a temperature of 1160 ℃ and a pressure of 160±10 MPa for 3 hours. Then, solution strengthening is performed by heating to 1180 ℃ at a rate of 8 ℃ / min and holding for 2 hours.

[0041] Performance test results: No obvious microcracks were observed after heat treatment of the mixed powder printing; the micropore size was ≤4 μm; the room temperature microhardness was 386 HV, which was 30.4% higher than that of pure GH3230 undoped printed components; the yield strength was 858 MPa, the tensile strength was 1042 MPa, the elongation was 12.8%, and after holding at 800 ℃ for 100 hours, the antioxidant weight gain was ≤0.9 mg / cm³. 2 .

[0042] Comparative Example 1 The basic powder ratio and pretreatment, basic GH3230 powder preparation, SLM printing process, and post-forming heat treatment were all the same as in Example 1, with no added doped powder.

[0043] Performance test results: Electron microscopy revealed numerous microcracks after printing without powder mixing. The room temperature microhardness was 296 HV, yield strength was 536 MPa, tensile strength was 564 MPa, elongation was 1.73%, and after 100 hours of heat treatment at 800 ℃, the antioxidant weight gain was ≤1.2 mg / cm³. 2 .

[0044] Example 2

[0045] S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; Basic GH3230 powder preparation adopts electrode induction melting gas atomization process: Raw material smelting: The GH3230 master alloy rod is made into a consumable electrode, clamped in a lifting and rotating mechanism and fed into the ring induction coil of the vacuum induction furnace. The vacuum induction furnace body is evacuated to 3×10-3 Pa and then filled with high-purity argon gas to 0.07 MPa protective atmosphere. Medium frequency induction heating is used to make the electrode tip consumable melt to 1560 ℃ and hold for 15 minutes.

[0046] Atomization powder production: The atomizing tank is purged with high-purity argon four times, the atomizing nozzle is preheated to 380 ℃, and 3.5 MPa high-pressure argon is introduced into the nozzle. The heating power is adjusted to stabilize the temperature of the molten pool within the range required for atomization. The electrode descent rate is adjusted to form a stable droplet beam of molten metal. The high-pressure argon flow and the molten metal droplet beam converge and break it into fine droplets. The temperature of the molten metal exiting the tank is controlled at 1450 ℃, and it is broken into fine droplets of 10~150 μm. The droplets are rapidly cooled in an inert protective atmosphere to improve the powder cooling rate.

[0047] Powder sieving: After cooling, the powder is initially classified by a cyclone separator, and then finely screened by a combination of "ultrasonic vibration screen + airflow classification" to obtain GH3230 alloy powder with a particle size of 15~53 μm. The powder has a Hall flow rate of 13.5 s / 50g and a sphericity of 0.95.

[0048] Basic powder formulation and pretreatment: The GH3230 powder composition by mass fraction includes: C 0.12%, Cr 23.2%, Co 4.1%, W 14.6%, Mo 2.7%, Al 0.42%, Ti 0.08%, Fe 2.6%, La 0.035%, B 0.013%, Si 0.65%, Mn 0.85%, with the balance being Ni and unavoidable trace impurities. The powder was dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0049] Doping powder ratio and pretreatment: Niobium powder with a purity ≥99.9% was selected, with an average particle size of 4 μm. The mass of the niobium powder was 1.0% of the mass of the base GH3230 powder. The powders were dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0050] Composite powder preparation: A high-speed mixer was used for mixing. The mixing speed was set to 1600 rpm and the mixing time was 1.5 minutes each time. After mixing, the mixture was cooled for 25 minutes. The mixing was repeated 3 times. SEM detection confirmed that the particles were uniformly attached, the agglomerate size was ≤3 μm, and the mixing uniformity was ≥96%.

[0051] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing process: The SLM 280 metal additive manufacturing equipment is used, and the oxygen content in the printing chamber is controlled below 0.05%. The laser power is 200 W, the scanning speed is 900 mm / s, the powder layer thickness is 45 μm, the scanning spacing is 120 μm, and a bidirectional interlaced scanning mode is adopted with a 60° deflection between layers.

[0052] S3: Perform post-forming heat treatment on the printed component; Post-forming heat treatment: First, hot isostatic pressing is performed at a temperature of 1180 ℃ and a pressure of 160±10 MPa for 3 hours. Then, solution strengthening is performed by heating to 1160 ℃ at a rate of 10 ℃ / min and holding for 1 hour.

[0053] Performance test results: Electron microscopy revealed no microcracks in the component, and the fracture morphology was more ductile than that of the component without powder mixing. The room temperature microhardness was 405 HV, which is 36.8% higher than that of the pure GH3230 undoped printed component. The yield strength was 912 MPa, the tensile strength was 1128 MPa, the elongation was 13.5%, and the creep rupture life at 800 ℃ was 55% higher than that of the pure GH3230 undoped printed component. It has excellent high-temperature oxidation resistance and is fully suitable for the service requirements of aerospace hot-end components.

[0054] Comparative Example 2 The basic powder ratio and pretreatment, basic GH3230 powder preparation, SLM printing process, and post-forming heat treatment were all the same as in Example 2, with no added doped powder.

[0055] Performance test results: room temperature microhardness 298 HV, yield strength 539 MPa, tensile strength 566 MPa, elongation 1.71%, after being kept at 800 ℃ for 100 hours, the antioxidant weight gain ≤1.3 mg / cm2, and the creep rupture life at 800 ℃ is about 55% lower than that of Example 2.

[0056] Example 3

[0057] S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; Basic GH3230 powder was prepared using a plasma rotating electrode process: Raw material smelting: The GH3230 master alloy rod is made into an electrode, clamped on the high-speed rotating spindle of the equipment and placed in the plasma rotating electrode powder making furnace. After the vacuum induction furnace body is evacuated to 5×10-3 Pa, high-purity argon gas is introduced to a protective atmosphere of 0.05~0.1 MPa. The electrode tip is heated by plasma arc focusing and heated to 1560 ℃ at a rate of 8 ℃ / min. The temperature is held for 20 minutes. The plasma power is adjusted to stabilize the temperature of the melting area at the electrode tip within the range required for atomization.

[0058] Atomization powder production: High-purity argon gas is introduced into the furnace for purging three times. The plasma power and electrode rotation speed are adjusted so that the molten metal is thrown out under centrifugal force to form fine droplets of 10~150 μm. The temperature of the molten metal is controlled at 1540℃. The droplets are rapidly cooled and shaped in an inert protective atmosphere to obtain the initial powder.

[0059] Powder sieving: After initial separation by a sedimentation classifier, the cooled initial powder is finely classified by an ultrasonic vibrating screen. Large particles are first removed by passing through a 200-mesh screen, and then screened through a 400-mesh screen to finally obtain basic GH3230 powder with a particle size distribution of 15~53 μm, a Hall flow rate of 13.8 s / 50g, and a sphericity of 0.94.

[0060] The GH3230 powder composition by mass fraction includes: C 0.09%, Cr 22.5%, Co 3.2%, W 14.2%, Mo 2.1%, Al 0.35%, Ti 0.06%, Fe 2.2%, La 0.025%, B 0.010%, Si 0.50%, Mn 0.65%, with the balance being Ni and unavoidable trace impurities. The powder was dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0061] Doping powder ratio and pretreatment: Tungsten powder with a purity of ≥99.9% and an average particle size of 3 μm was selected, and the mass of the tungsten powder was 1.5% of the mass of the base GH3230 powder. The powders were dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0062] Composite powder preparation: The powder was mixed using a high-speed mixer at a speed of 1500 rpm for 1.2 minutes each time. After mixing, the powder was allowed to cool naturally for 20 minutes. The mixing was repeated 3 times. The powder was confirmed to be uniformly mixed and free of obvious agglomerates by scanning electron microscopy, thus obtaining the composite powder.

[0063] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing process: The SLM 280 metal additive manufacturing equipment is used. High-purity argon gas is introduced into the printing chamber, and the oxygen content is controlled below 0.06%. The laser power is 190 W, the scanning speed is 800 mm / s, the powder layer thickness is 40 μm, the scanning spacing is 110 μm, and a bidirectional staggered scanning mode is adopted with a 60° deflection between layers.

[0064] S3: Perform post-forming heat treatment on the printed component; Post-forming heat treatment: First, hot isostatic pressing is performed at a temperature of 1200 ℃ and a pressure of 160±10 MPa for 2 hours. Then, solution strengthening is performed by heating to 1200 ℃ at a rate of 10 ℃ / min and holding for 2 hours.

[0065] Performance test results: Electron microscopy revealed no visible microcracks inside the component, and tungsten nucleation sites were found on the surface under high magnification. The room temperature microhardness was 392 HV, a 32.4% improvement compared to undoped pure GH3230 printed components. The yield strength was 886 MPa, the tensile strength was 1085 MPa, and the elongation was 13.2%. After being kept at 800 ℃ for 100 hours, the oxidation weight gain was ≤0.8 mg / cm³. 2 .

[0066] Comparative Example 3 The basic powder ratio and pretreatment, basic GH3230 powder preparation, SLM printing process, and post-forming heat treatment were all the same as in Example 3, with no added doped powder.

[0067] Performance test results: room temperature microhardness is 300 HV, yield strength is 540 MPa, tensile strength is 570 MPa, elongation is 1.72%, and after being kept at 800 ℃ for 100 hours, the antioxidant weight gain is ≤1.1 mg / cm³. 2 .

[0068] Example 4

[0069] Basic powder formulation and pretreatment: The mass fraction of GH3230 powder components is the same as in Example 1. The powder is dried in a vacuum drying oven at 120°C for 2 hours.

[0070] Doping powder formulation and pretreatment: Molybdenum powder with a purity ≥99.9% and an average particle size of 2 μm was selected, with the mass of molybdenum powder being 0.2% of the mass of the base GH3230 powder. Niobium powder with a purity ≥99.9% and an average particle size of 4 μm was selected, with the mass of niobium powder being 0.3% of the mass of the base GH3230 powder. Tungsten powder with a purity ≥99.9% and an average particle size of 3 μm was selected, with the mass of tungsten powder being 0.5% of the mass of the base GH3230 powder. All powders were dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0071] The preparation of basic GH3230 powder is the same as in Example 1.

[0072] Composite powder preparation: The mixture was prepared by mixing with a high-speed mixer at 1500 rpm for 1.2 minutes each time. After cooling for 20 minutes, the mixing was repeated 3 times. The uniformity of the mixture was ≥95% to obtain the composite powder.

[0073] SLM printing process: The SLM 280 metal additive manufacturing equipment is used. The core process parameters are adjusted as follows: laser power 200 W, scanning speed 850 mm / s, powder layer thickness 42 μm, scanning spacing 115 μm, scanning strategy is bidirectional staggered scanning, interlayer scanning angle deflection 60°, and oxygen content in the printing chamber is controlled below 0.05%.

[0074] Post-forming heat treatment: First, hot isostatic pressing is performed at a temperature of 1080 ℃ and a pressure of 160±10 MPa for 3 hours. Then, solution strengthening is performed by heating to 1180 ℃ at a rate of 8 ℃ / min and holding for 2 hours.

[0075] Performance test results: No obvious microcracks were observed after heat treatment of the mixed powder printing. The room temperature microhardness was 389 HV, which is 30.5% higher than that of pure GH3230 undoped printed components; the yield strength was 860 MPa, the tensile strength was 1045 MPa, the elongation was 12.9%, and after holding at 800 ℃ for 100 hours, the antioxidant weight gain was ≤0.85 mg / cm³. 2 .

[0076] Comparative Example 4 The basic powder ratio and pretreatment, basic GH3230 powder preparation, SLM printing process, and post-forming heat treatment were all the same as in Example 4, with no added doped powder.

[0077] Performance test results: room temperature microhardness 296 HV, yield strength 536 MPa, tensile strength 564 MPa, elongation 1.80%, after being kept at 800 ℃ for 100 hours, the antioxidant weight gain ≤1.2 mg / cm2.

[0078] Experimental Example 1 Molybdenum powder with a purity of ≥99.9% was selected, with an average particle size of 2 μm. The doping amount was 0.05% of the mass of the base GH3230 powder. The remaining preparation, printing, and heat treatment processes were completely consistent with those in Example 1.

[0079] Experimental conclusions: A large number of fine flower-shaped microcracks still exist inside the component, and the crack elimination effect is extremely poor; the room temperature microhardness is 310 HV, which is only 4.7% higher than that of pure GH3230 undoped printed components; the yield strength is 585 MPa, the tensile strength is 620 MPa, and the elongation is 3.2%, with a slight improvement in mechanical properties, which cannot solve the original cracking problem and performance shortcomings.

[0080] Experimental Example 2 Molybdenum powder with a purity of ≥99.9% was selected, with an average particle size of 2 μm. The doping amount was 3.0% of the mass of the base GH3230 powder. The remaining preparation, printing, and heat treatment processes were completely consistent with those in Example 1.

[0081] Experimental conclusions: Excessive addition of molybdenum powder resulted in severe agglomeration, leading to insufficient powder melting during printing. This resulted in coarse cracks and numerous pores in the components, with the maximum crack width reaching 30 μm. Although the room temperature microhardness increased to 410 HV, the yield strength was only 720 MPa, the tensile strength 750 MPa, and the elongation only 2.5%. After holding at 800 ℃ for 100 hours, the antioxidant weight gain was 1.8 mg / cm³. 2 Its high-temperature performance has decreased significantly.

[0082] Experimental Example 3 Niobium powder with a purity of ≥99.9% was selected, with an average particle size of 4 μm. The doping amount was 0.1% of the mass of the base GH3230 powder. The remaining preparation, printing, and heat treatment processes were completely consistent with those in Example 2.

[0083] Experimental conclusions: There are obvious microcracks inside the component, and the crack elimination effect is not as expected; the room temperature microhardness is 325HV, which is 9.8% higher than that of the pure GH3230 printed component; the yield strength is 630 MPa, the tensile strength is 680 MPa, and the elongation is 4.5%, with limited improvement in mechanical properties and no significant improvement in high temperature creep performance.

[0084] Experiment Example 4 Niobium powder with a purity of ≥99.9% was selected, with an average particle size of 4 μm. The doping amount was 2.0% of the mass of the base GH3230 powder. The remaining preparation, printing, and heat treatment processes were completely consistent with those in Example 2.

[0085] Experimental conclusions: Excess niobium powder causes interfacial stress concentration with the GH3230 alloy matrix, resulting in large cracks in the component, accompanied by microstructure segregation. The room temperature microhardness is 395 HV, yield strength is 705 MPa, tensile strength is 740 MPa, and elongation is 3.8%, indicating a decrease in mechanical properties. Furthermore, high-temperature oxidation resistance is reduced; after holding at 800 ℃ for 100 hours, the oxidation weight gain is 1.5 mg / cm³. 2 .

[0086] Experimental Example 5 Tungsten powder with a purity of ≥99.9% was selected, with an average particle size of 3 μm. The doping amount was 0.1% of the mass of the base GH3230 powder. The remaining preparation, printing, and heat treatment processes were completely consistent with those in Example 3.

[0087] Experimental conclusions: Microcracks still exist inside the component, and the crack suppression effect is weak; the room temperature microhardness is 320 HV, which is 8.1% higher than that of the pure GH3230 printed component; the yield strength is 610 MPa, the tensile strength is 660 MPa, the elongation is 4.0%, and there is no significant improvement in mechanical properties and high temperature thermal stability.

[0088] Experimental Example 6 Tungsten powder with a purity of ≥99.9% was selected, with an average particle size of 3 μm. The doping amount was 3.0% of the mass of the base GH3230 powder. The remaining preparation, printing, and heat treatment processes were completely consistent with those in Example 3.

[0089] Experimental conclusions: Excessive tungsten powder leads to decreased powder flowability, uneven powder spreading, and cracks, pores, and incomplete fusion defects in the printed components; the room temperature microhardness is 400 HV, the yield strength is 690 MPa, the tensile strength is 720 MPa, and the elongation is 3.0%, indicating a deterioration in mechanical properties. Furthermore, the excessive precipitation of tungsten leads to an abnormal high-temperature thermal expansion coefficient of the alloy, making it unable to meet the dimensional stability requirements of high-temperature components.

[0090] Example 5

[0091] S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; Basic GH3230 powder was prepared using a vacuum induction gas atomization process: Raw material smelting: The vacuum induction furnace is evacuated to 10°C. -2 Pa, fill with high-purity argon gas to a protective atmosphere of 0.05 MPa; place the basic component raw materials in a vacuum induction furnace, and heat with medium frequency induction heating to 1540 ℃ to completely melt the raw materials, and hold for 5 minutes for refining.

[0092] Atomization powder preparation: The atomizing tank is purged with argon gas once. After the gas filling is completed, the temperature is reduced to 1400 ℃. The molten metal flows into the atomizing nozzle through the bottom guide hole of the heat-insulating intermediate tank. The outlet temperature of the molten metal is 1400 ℃. The nozzle is preheated to 320 ℃. High-pressure argon gas of 3MPa is introduced into the atomizing nozzle. The gas flow and the molten metal flow converge and break into fine droplets of 10~150 μm. The droplets form spherical shapes due to surface tension during the falling process. They are rapidly cooled in an inert atmosphere. The powder is classified by a cyclone separator and falls into a collection tank. After cooling to room temperature, it is taken out to obtain the initial powder.

[0093] Powder sieving: After ultrasonic vibration sieving, basic powder with a particle size distribution of 15~53 μm is obtained, with a Hall flow rate of 15s / 50g and a sphericity of 0.85.

[0094] Basic powder formulation and pretreatment: The GH3230 powder composition by mass fraction includes: C 0.05%, Cr 20%, Co 1%, W 13%, Mo 1%, Al 0.2%, Ti 0.01%, Fe 0.01%, La 0.005%, B 0.01%, Si 0.25%, Mn 0.3%, with the balance being Ni and unavoidable trace impurities. The powder was dried in a vacuum drying oven at 80 ℃ for 1 hour.

[0095] Doping powder formulation and pretreatment: Molybdenum powder with a purity ≥99.9% was selected as the single dopant phase, with a doping amount of 0.2% of the mass of the base GH3230 powder and an average particle size of 2 μm. The powders were dried in a vacuum drying oven at 80 ℃ for 1 hour.

[0096] Composite powder preparation: A high-speed mixer was used for mixing. The mixing speed was set to 1300 rpm and the mixing time was 1 minute each time. After mixing, the mixture was cooled for 15 minutes. The mixing was repeated twice. The powder uniformity was tested to be ≥92% and there was no obvious agglomeration. GH3230-Mo composite powder was obtained.

[0097] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing process: SLM metal additive manufacturing equipment is used. The printing chamber is filled with high-purity argon gas, and the oxygen content is controlled at 0.1%. The core process parameters are selected to match the lower limit of the composition: laser power 170 W, scanning speed 650 mm / s, powder layer thickness 30 μm, scanning spacing 70 μm, scanning strategy is bidirectional staggered scanning, interlayer scanning angle deflection 60°, and argon gas protection is used during the forming process to avoid powder oxidation.

[0098] S3: Perform post-forming heat treatment on the printed component; Heat treatment after forming: First, hot isostatic pressing is performed at a temperature of 1080 ℃ and a pressure of 160±10 MPa for 1 hour; then, solution strengthening is performed by heating to 1160 ℃ at a rate of 8 ℃ / min and holding for 1 hour, followed by forced cooling to room temperature with argon gas.

[0099] Performance test results: Metallographic examination revealed no obvious microcracks in the component, with only a small number of tiny pores ≤3 μm in size, indicating that the crack elimination effect met the standard; the room temperature microhardness was 385 HV, which is 30.1% higher than that of the pure GH3230 undoped printed component; the yield strength was 850 MPa and the tensile strength was 1030 MPa, both meeting the lower limit of the present invention, with an elongation of 12.5%; after being kept at 800 ℃ for 100 hours, the antioxidant weight gain was ≤0.95 mg / cm³. 2 .

[0100] Example 6

[0101] S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; Basic GH3230 powder was prepared using a vacuum induction gas atomization process: Raw material smelting: The vacuum induction furnace is evacuated to 10°C. -3 Pa, fill with high-purity argon gas to a protective atmosphere of 0.1 MPa; place the basic component raw materials in a vacuum induction furnace, and heat with medium frequency induction heating to 1570 ℃ to completely melt the raw materials, and hold for 20 minutes for refining.

[0102] Atomization powder preparation: The atomizing barrel is purged with argon three times. After the purging is completed, the temperature is reduced to 1450 ℃. The molten metal flows into the atomizing nozzle through the bottom guide hole of the heat-insulating intermediate pot. The outlet temperature of the molten metal is 1450 ℃. The nozzle is preheated to 320 ℃. 6MPa high-pressure argon gas is introduced into the atomizing nozzle. The gas flow and the molten metal flow converge and break into fine droplets of 10~150 μm. The droplets form spherical shapes due to surface tension during the falling process. They are rapidly cooled in an inert atmosphere. The powder is classified by a cyclone separator and falls into a collection tank. After cooling to room temperature, it is taken out to obtain the initial powder.

[0103] Powder sieving: After ultrasonic vibration sieving, basic powder with a particle size distribution of 15~53 μm is obtained, with a Hall flow rate of 12s / 50g and a sphericity of 0.92.

[0104] Composite powder preparation: A high-speed mixer was used for mixing, with a mixing speed of 1700 rpm and a mixing time of 1.5 minutes each time. After mixing, the mixture was cooled for 25 minutes. The mixing was repeated 3 times. The powder mixing uniformity was tested to be ≥96%, and there was no agglomeration. GH3230-Mo composite powder was obtained.

[0105] Basic powder formulation and pretreatment: The GH3230 powder composition by mass fraction includes: C 0.15%, Cr 24%, Co 5%, W 15%, Mo 3%, Al 0.5%, Ti 0.1%, Fe 3%, La 0.05%, B 0.015%, Si 0.75%, Mn 1%, with the balance being Ni and unavoidable trace impurities. The powder was dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0106] Doping powder formulation and pretreatment: Molybdenum powder with a purity ≥99.9% was selected as the single dopant phase, with a doping amount of 2.0% of the mass of the base GH3230 powder and an average particle size of 4 μm. The powders were dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0107] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing process: SLM metal additive manufacturing equipment is used. The printing chamber is filled with high-purity argon gas, and the oxygen content is controlled at 0.05%. The core process parameters are selected to match the upper limit of the composition: laser power 310 W, scanning speed 1050 mm / s, powder layer thickness 70 μm, scanning spacing 130 μm, scanning strategy is bidirectional staggered scanning, and the interlayer scanning angle is deflected by 60°.

[0108] S3: Perform post-forming heat treatment on the printed component; Heat treatment after forming: First, hot isostatic pressing is performed at a temperature of 1200 ℃ and a pressure of 160±10 MPa for 5 hours; then, solution strengthening is performed by heating to 1200 ℃ at a rate of 12 ℃ / min and holding for 4 hours, followed by forced cooling to room temperature with argon gas.

[0109] Performance test results: Metallographic examination revealed no microcracks in the component, indicating a dense internal structure with micropores ≤2μm in size, demonstrating excellent crack elimination. The room temperature microhardness was 412 HV, a 39.2% improvement compared to undoped pure GH3230 printed components. Yield strength was 925 MPa, tensile strength 1150 MPa, and elongation 13.8%, showing a significant improvement in mechanical properties. After holding at 800 ℃ for 100 hours, the antioxidant weight gain was ≤0.8 mg / cm³. 2 Its high-temperature oxidation resistance and thermal stability are superior to those of pure GH3230 alloy, making it suitable for high-end high-temperature service scenarios such as hot-end components of aerospace engines.

[0110] Example 7

[0111] S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; The basic GH3230 powder was prepared using an electrode induction melting gas atomization process. Raw material smelting: The GH3230 master alloy rod is made into a consumable electrode, clamped in a lifting and rotating mechanism, and fed into the annular induction coil of the vacuum induction furnace. The vacuum induction furnace body is evacuated to 10°C. -2 Pa, fill with high-purity argon gas to a protective atmosphere of 0.05 MPa; medium-frequency induction heating causes the electrode tip to self-melt to 1540 ℃, and hold for 5 minutes for refining.

[0112] The atomizing tank is purged twice with high-purity argon gas. The atomizing nozzle is preheated to 300 ℃. High-pressure argon gas of 3 MPa is introduced into the nozzle. The high-pressure argon gas flow converges with the metal droplet stream, breaking it into fine droplets of 10~150 μm. The temperature of the molten metal exiting the tank is controlled at 1400 ℃. The droplets are rapidly cooled in an inert protective atmosphere.

[0113] Powder sieving: After cooling, the powder is initially classified by a cyclone separator and then finely screened by an ultrasonic vibrating screen to obtain GH3230 alloy powder with a particle size of 15~53 μm. The Hall flow rate of the powder was measured to be 15 s / 50g and the sphericity was 0.85, which meets the powder spreading requirements for SLM printing.

[0114] Basic powder formulation and pretreatment: The composition of GH3230 powder is the same as in Example 5. It is dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0115] Doping powder formulation and pretreatment: Niobium powder with a purity ≥99.9% was selected as the single doping phase, with a doping amount of 0.2% of the mass of the base GH3230 powder and an average particle size of 4 μm. The powders were dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0116] Composite powder preparation: A high-speed mixer was used for mixing. The mixing speed was set to 1300 rpm and the mixing time was 1 minute each time. After mixing, the mixture was cooled for 15 minutes. The mixing was repeated twice. SEM detection confirmed that the niobium powder particles were uniformly attached to the surface of GH3230 powder, the agglomerate size was ≤3 μm, and the mixing uniformity was ≥92%, thus obtaining GH3230-Nb composite powder.

[0117] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing process: SLM metal additive manufacturing equipment is used. The printing chamber is filled with high-purity argon gas and the oxygen content is controlled at 0.1%. The core process parameters are selected to match the lower limit of the process: laser power 170 W, scanning speed 650 mm / s, powder layer thickness 30 μm, scanning spacing 70 μm, bidirectional staggered scanning mode, and interlayer scanning angle deflection 60°.

[0118] S3: Perform post-forming heat treatment on the printed component; Heat treatment after forming: First, hot isostatic pressing is performed at a temperature of 1080 ℃ and a pressure of 160±10 MPa for 1 hour; then solid solution strengthening is performed by heating to 1160 ℃ at a rate of 8 ℃ / min and holding for 1 hour, followed by forced cooling with argon gas to suppress the precipitation of harmful phases.

[0119] Performance test results: Metallographic examination revealed no obvious microcracks in the component, with only a small number of tiny pores ≤3 μm in size, achieving the basic requirements for crack elimination. The room temperature microhardness was 390 HV, a 31.8% improvement compared to undoped pure GH3230 printed components. The yield strength was 865 MPa, tensile strength 1055 MPa, and elongation 12.7%, all meeting the mechanical properties standards. After holding at 800 ℃ for 100 hours, the antioxidant weight gain was ≤0.92 mg / cm³. 2 Its high-temperature oxidation resistance is comparable to that of pure GH3230 alloy, and its high-temperature creep performance at 800 ℃ is 40% better than that of pure powder printed components.

[0120] Example 8

[0121] S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; The basic GH3230 powder was prepared using an electrode induction melting gas atomization process. Raw material smelting: The GH3230 master alloy rod is made into a consumable electrode, clamped in a lifting and rotating mechanism, and fed into the annular induction coil of the vacuum induction furnace. The vacuum induction furnace body is evacuated to 10°C. -3 Pa, fill with high-purity argon gas to a protective atmosphere of 0.1 MPa; medium-frequency induction heating causes the electrode tip to self-melt to 1570 ℃, and hold for 20 minutes for refining.

[0122] Atomization powder production: The atomizing barrel is purged with high-purity argon four times, the atomizing nozzle is preheated to 400 ℃, and 6 MPa high-pressure argon is introduced into the nozzle. The high-pressure argon flow and the metal droplet beam converge and break into fine droplets. The temperature of the molten metal is controlled at 1450 ℃ to improve the powder cooling rate and optimize the powder sphericity.

[0123] Powder sieving: After cooling, the powder is initially classified by a cyclone separator and then finely screened by an ultrasonic vibrating screen to obtain GH3230 alloy powder with a particle size of 15~53 μm. The Hall flow rate of the powder was measured to be 12.5 s / 50g, the sphericity was 0.94, and the powder density was excellent.

[0124] Basic powder formulation and pretreatment: The composition of GH3230 powder is the same as in Example 6. It is dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0125] Doping powder formulation and pretreatment: Niobium powder with a purity ≥99.9% was selected as the single doping phase, with a doping amount of 1.5% of the mass of the base GH3230 powder and an average particle size of 4 μm. The powders were dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0126] Composite powder preparation: A high-speed mixer was used for mixing. The mixing speed was set to 1700 rpm and the mixing time was 1.5 minutes each time. After mixing, the mixture was cooled for 25 minutes. The mixing was repeated 3 times. SEM detection confirmed that the niobium powder particles were uniformly attached and there were no obvious agglomerates. The mixing uniformity was ≥97%, and GH3230-Nb composite powder was obtained.

[0127] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing process: SLM metal additive manufacturing equipment is used. The printing chamber is filled with high-purity argon gas, and the oxygen content is controlled at 0.05%. The core process parameters are selected to match the upper limit of the process: laser power 310 W, scanning speed 1050 mm / s, powder layer thickness 70 μm, scanning spacing 130 μm, bidirectional staggered scanning mode, and interlayer scanning angle deflection 60°.

[0128] S3: Perform post-forming heat treatment on the printed component; Heat treatment after forming: First, hot isostatic pressing is performed at a temperature of 1200 ℃ and a pressure of 160±10 MPa for 5 hours; then solid solution strengthening is performed by heating to 1200 ℃ at a rate of 12 ℃ / min and holding for 4 hours, followed by forced cooling with argon gas to ensure that the alloying elements are fully dissolved and to eliminate microstructure segregation.

[0129] Performance test results: Metallographic examination revealed no microcracks in the component, with a dense and uniform internal structure and micropores ≤2 μm in size, demonstrating excellent crack elimination. The room temperature microhardness was 418 HV, a 41.2% improvement compared to undoped pure GH3230 printed components. Yield strength was 935 MPa, tensile strength 1165 MPa, and elongation 14.0%, indicating a significant improvement in mechanical properties. The fracture morphology exhibited typical ductile fracture characteristics. After holding at 800 ℃ for 100 hours, the antioxidant weight gain was ≤0.78 mg / cm³. 2 The creep fracture life at 800℃ is 60% higher than that of pure powder printed components. It has excellent high-temperature thermal stability and oxidation resistance, and is fully adapted to the stringent requirements of high-end high-temperature service scenarios such as hot-end components of aerospace engine combustion chambers.

[0130] Example 9

[0131] S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; The basic GH3230 powder was prepared using a plasma rotating electrode process: Raw material smelting: GH3230 master alloy rods are made into electrodes, clamped on the high-speed rotating spindle of the equipment, and placed in a plasma rotating electrode powder making furnace. The vacuum induction furnace body is evacuated to 10°C. -2 Pa, high-purity argon gas is introduced to a protective atmosphere of 0.05 MPa; the electrode tip is heated by plasma arc focusing, and the temperature is increased to 1540 ℃ at a rate of 6 ℃ / min, and the temperature is held for 5 minutes for refining. The plasma power is adjusted to stabilize the temperature of the melting area at the electrode tip within the range required for atomization.

[0132] Atomization powder making: High-purity argon gas is introduced into the furnace twice for purging. The plasma power and electrode rotation speed are adjusted so that the molten metal is thrown out under centrifugal force to form fine droplets. The temperature of the molten metal is controlled at 1400 ℃. The droplets are rapidly cooled and shaped in an inert protective atmosphere to obtain the initial powder.

[0133] Powder sieving: After initial separation by a sedimentation classifier, the cooled initial powder is finely classified by an ultrasonic vibrating sieve to obtain basic GH3230 powder with a particle size distribution of 15~53 μm. The Hall flow rate of the powder was measured to be 15 s / 50g and the sphericity was 0.85, which meets the powder spreading requirements for SLM printing.

[0134] Basic powder formulation and pretreatment: The composition of GH3230 powder is the same as in Example 5. It is dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0135] Doping powder formulation and pretreatment: Tungsten powder with a purity ≥99.9% was selected as the single dopant phase, with a doping amount of 0.2% of the mass of the base GH3230 powder and an average particle size of 4 μm. The powders were dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0136] Composite powder preparation: A high-speed mixer was used for mixing, with a mixing speed of 1300 rpm and a mixing time of 1 minute each time. After mixing, the mixture was cooled for 15 minutes and the mixing was repeated twice. SEM detection confirmed that the tungsten powder particles were uniformly attached to the surface of the GH3230 powder without obvious agglomeration and the mixing uniformity was ≥92%, thus obtaining the GH3230-W composite powder.

[0137] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing process: SLM metal additive manufacturing equipment is used. The printing chamber is filled with high-purity argon gas and the oxygen content is controlled at 0.1%. The core process parameters are selected to match the lower limit of the process: laser power 170 W, scanning speed 650 mm / s, powder layer thickness 30 μm, scanning spacing 70 μm, bidirectional staggered scanning mode, and interlayer scanning angle deflection 60°.

[0138] S3: Perform post-forming heat treatment on the printed component; Heat treatment after forming: First, hot isostatic pressing is performed at a temperature of 1080 ℃ and a pressure of 160±10 MPa for 1 hour; then solid solution strengthening is performed by heating to 1160 ℃ at a rate of 8 ℃ / min and holding for 1 hour. Subsequently, argon gas is used for forced cooling to suppress the precipitation of harmful phases and eliminate microstructure segregation.

[0139] Performance test results: Metallographic examination revealed no obvious microcracks in the component, with only a small number of tiny pores ≤3 μm in size. The crack elimination effect met the basic indicators of this invention. The room temperature microhardness was 388 HV, which is 31.1% higher than that of the pure GH3230 undoped printed component. The yield strength was 862 MPa, the tensile strength was 1048 MPa, and the elongation was 12.6%, all meeting the mechanical properties standards. After being kept at 800 ℃ for 100 hours, the antioxidant weight gain was ≤0.90 mg / cm³. 2 Its high-temperature thermal stability is comparable to that of pure GH3230 alloy, and its high-temperature deformation resistance at 800 ℃ is 35% higher than that of pure powder printed components.

[0140] Example 10

[0141] S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; The basic GH3230 powder was prepared using a plasma rotating electrode process: (1) Raw material smelting: The GH3230 master alloy rod is made into an electrode, clamped in the high-speed rotating spindle of the equipment and placed in the plasma rotating electrode powder making furnace. The vacuum induction furnace body is evacuated to 10 -3 Pa, high-purity argon gas is introduced to a protective atmosphere of 0.1 MPa; the electrode tip is heated by plasma arc focusing, and the temperature is increased to 1570 ℃ at a rate of 9 ℃ / min, and the temperature is held for 20 minutes for refining. The plasma power is precisely controlled to stabilize the temperature of the melting area at the electrode tip within the optimal atomization range.

[0142] Atomization powder production: High-purity argon gas is introduced into the furnace four times for purging, and the plasma power and electrode rotation speed are precisely matched so that the molten metal is evenly thrown out under the action of centrifugal force to form fine droplets. The temperature of the molten metal exiting the furnace is controlled at 1450 ℃ to improve the cooling rate of the droplets and optimize the sphericity and density of the powder. The droplets are rapidly cooled and shaped in an inert protective atmosphere to obtain the initial powder.

[0143] Powder sieving: After cooling, the initial powder was finely separated by a sedimentation classifier to obtain basic GH3230 powder with a particle size distribution of 15~53 μm. The Hall flow rate of the powder was measured to be 12 s / 50g, the sphericity was 0.95, and the powder density and flowability were excellent.

[0144] Basic powder formulation and pretreatment: The composition of GH3230 powder is the same as in Example 6. It is dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0145] Doping powder formulation and pretreatment: Tungsten powder with a purity ≥99.9% was selected as the single dopant phase, with a doping amount of 2.5% of the mass of the base GH3230 powder and an average particle size of 3 μm. The powders were dried in a vacuum drying oven at 120 ℃ for 2 hours.

[0146] Composite powder preparation: A high-speed mixer was used for mixing, with a mixing speed of 1700 rpm and a mixing time of 1.5 minutes each time. After mixing, the mixture was cooled for 25 minutes and the mixing was repeated 3 times. SEM detection confirmed that the tungsten powder particles were uniformly coated on the surface of GH3230 powder without agglomerates and the mixing uniformity was ≥97%, thus obtaining GH3230-W composite powder.

[0147] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing process: SLM metal additive manufacturing equipment is used. The printing chamber is filled with high-purity argon gas, and the oxygen content is controlled at 0.05%. The core process parameters are selected to match the upper limit of the process: laser power 310 W, scanning speed 1050 mm / s, powder layer thickness 70 μm, scanning spacing 130 μm, bidirectional staggered scanning mode, and interlayer scanning angle deflection 60°.

[0148] S3: Perform post-forming heat treatment on the printed component; Post-forming heat treatment: First, hot isostatic pressing is performed at a temperature of 1200 ℃ and a pressure of 160±10 MPa for 5 hours; then, solution strengthening treatment is performed by heating to 1200 ℃ at a rate of 12 ℃ / min and holding for 4 hours, followed by forced cooling with argon gas to ensure that tungsten elements are fully dissolved in the alloy matrix, effectively reducing microstructure segregation and internal stress.

[0149] Performance test results: Metallographic examination revealed that the internal structure of the component was dense and uniform, with no visible microcracks and micropores ≤2 μm in size. Tungsten formed uniformly distributed nucleation sites in the matrix. The room temperature microhardness was 425 HV (approximately 43.4% higher than that of undoped pure GH3230 printed components). The yield strength was 950 MPa, the tensile strength was 1180 MPa, and the elongation was 14.2%. After being held at 800 ℃ for 100 hours, the oxidation weight gain was ≤0.75 mg / cm³. 2 The high-temperature creep fracture life at 800 ℃ is improved by about 65% compared with the pure GH3230 undoped printed components.

[0150] Example 11

[0151] S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; Basic powder formulation and pretreatment: Same as in Example 5. Vacuum drying at 120℃ for 2 hours.

[0152] Doping powder ratio and pretreatment: Molybdenum powder: 0.1% (base powder mass, average particle size 2μm) Niobium powder: 0.1% (base powder mass, average particle size 4μm) Total addition: 0.2%. Vacuum dried at 120℃ for 2h.

[0153] Preparation of GH3230 base powder: Same as in Example 5. Preparation of composite powder: Mix at 1300 rpm for 1 min, cool for 15 min, repeat twice, with a mixing uniformity ≥92%.

[0154] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing parameters: laser power 170W, scanning speed 650mm / s, powder layer thickness 30μm, scanning spacing 70μm, oxygen content ≤0.1%. Heat treatment: hot isostatic pressing 1080℃ / 160MPa / 1h; solution treatment 1160℃ / 1h, rapid cooling with argon.

[0155] S3: Perform post-forming heat treatment on the printed component; Performance test results: The component showed no obvious microcracks, and the porosity was ≤3μm; the room temperature hardness was 387 HV, an increase of 30.7%; the yield strength was 855 MPa, the tensile strength was 1038 MPa, and the elongation was 12.6%; after being kept at 800℃ for 100 hours, the weight gain due to oxidation was ≤0.93mg / cm³. 2 High-temperature creep life is increased by 42%.

[0156] Example 12

[0157] S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; Basic powder formulation and pretreatment: Same as in Example 6. Vacuum drying at 120℃ for 2 hours.

[0158] Doping powder ratio and pretreatment: molybdenum powder: 1.0%, niobium powder: 1.5%, total addition: 2.5%. Vacuum drying at 120℃ for 2 hours.

[0159] Preparation of GH3230 base powder: Same as in Example 6. Preparation of composite powder: Mix at 1700 rpm for 1.5 min, cool for 25 min, repeat 3 times, uniformity ≥97%.

[0160] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing parameters: laser power 310W, scanning speed 1050mm / s, powder layer thickness 70μm, scanning spacing 130μm, oxygen content ≤0.05%. Heat treatment: hot isostatic pressing 1200℃ / 160MPa / 5h; solution treatment 1200℃ / 4h, rapid cooling with argon.

[0161] S3: Perform post-forming heat treatment on the printed component; Performance test results: No cracks, dense structure, pores ≤2μm; room temperature hardness 422 HV, an increase of 42.6%; yield strength 940 MPa, tensile strength 1170 MPa, elongation 13.9%; oxidation weight gain at 800℃ ≤0.76mg / cm³. 2 Creep life is improved by 63%.

[0162] Example 13

[0163] S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; Basic powder formulation and pretreatment: Same as in Example 5. Vacuum drying at 120℃ for 2 hours.

[0164] Doping powder ratio and pretreatment: molybdenum powder: 0.1%, tungsten powder: 0.1%, total addition: 0.2%. Vacuum drying at 120℃ for 2 hours.

[0165] Preparation of GH3230 base powder: Same as in Example 5. Preparation of composite powder: Mix at 1300 rpm for 1 min, cool for 15 min, repeat twice, uniformity ≥92%.

[0166] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing parameters: Same as the lower limit parameters in Example 5. Heat treatment: Same as the lower limit process in Example 5.

[0167] S3: Perform post-forming heat treatment on the printed component; Performance test results: No obvious cracks, porosity ≤3μm; room temperature hardness 386 HV, an increase of 30.4%; yield strength 853 MPa, tensile strength 1035 MPa, elongation 12.5%; oxidation weight gain at 800℃ ≤0.92mg / cm³.2 High-temperature deformation resistance is improved by 40%.

[0168] Example 14

[0169] S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; Basic powder formulation and pretreatment: Same as in Example 5. Vacuum drying at 120℃ for 2 hours.

[0170] Doping powder ratio and pretreatment: molybdenum powder: 1.5%, tungsten powder: 1.0%, total addition: 2.5%. Vacuum drying at 120℃ for 2 hours.

[0171] Preparation of GH3230 base powder: Same as in Example 6. Preparation of composite powder: Mix at 1700 rpm for 1.5 min, cool for 25 min, repeat 3 times, uniformity ≥97%.

[0172] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing parameters: Same as the lower limit parameters in Example 6. Heat treatment: Same as the lower limit process in Example 6.

[0173] S3: Perform post-forming heat treatment on the printed component; Performance test results: No cracks, dense and uniform microstructure, pore size ≤2μm; room temperature hardness 426 HV, an increase of 43.9%; yield strength 955 MPa, tensile strength 1185 MPa, elongation 14.1%; oxidation weight gain at 800℃ ≤0.74mg / cm³. 2 Creep life is improved by 66%.

[0174] Example 15

[0175] S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; Basic powder formulation and pretreatment: Same as in Example 5. Vacuum drying at 120℃ for 2 hours.

[0176] Doped powder formulation and pretreatment: Niobium powder: 0.1%, Tungsten powder: 0.1%, Total addition: 0.2%. Vacuum drying at 120℃ for 2 hours. GH3230 Basic powder preparation: Same as the lower limit process in Example 5. Composite powder preparation: Mix at 1300 rpm for 1 min, cool for 15 min, repeat twice, uniformity ≥92%.

[0177] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing parameters: Same as the lower limit parameters in Example 7. Heat treatment: Same as the lower limit process in Example 7.

[0178] S3: Perform post-forming heat treatment on the printed component; Performance test results: No obvious cracks, pores ≤3μm; room temperature hardness 390 HV, an increase of 31.8%; yield strength 868 MPa, tensile strength 1058 MPa, elongation 12.8%; oxidation weight gain at 800℃ ≤0.91mg / cm³. 2 Creep life is increased by 45%.

[0179] Example 16

[0180] S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; Basic powder formulation and pretreatment: Same as in Example 6. Vacuum drying at 120℃ for 2 hours.

[0181] Doped powder formulation and pretreatment: Niobium powder: 1.0%, Tungsten powder: 1.5%, Total addition: 2.5%. Vacuum drying at 120℃ for 2 hours. GH3230 Basic powder preparation: Same as the upper limit process in Example 6. Composite powder preparation: Mix at 1700 rpm for 1.5 min, cool for 25 min, repeat 3 times, uniformity ≥97%.

[0182] S2: The composite powder is printed using SLM printing technology to obtain a printed component; SLM printing parameters: Same as the upper limit parameters in Example 8. Heat treatment: Same as the upper limit process in Example 8.

[0183] S3: Perform post-forming heat treatment on the printed component; Performance test results: No cracks, dense structure, pores ≤2μm; room temperature hardness 424 HV, up 43.2%; yield strength 948 MPa, tensile strength 1175 MPa, elongation 14.0%; oxidation weight gain at 800℃ ≤0.75mg / cm³. 2 Creep life is improved by 64%.

[0184] The test results above are compared in the following table: The comparison of data between examples and comparative examples of crack suppression doped phases (single-element doping and mixed-element doping) is shown in Table 1 below:

[0185] Table 1 Table 2 below compares the data of crack suppression dopants below the lower limit and above the upper limit.

[0186] Table 2 The data comparison of the lower and upper limits for adding crack-inhibiting dopants is shown in Table 3 below.

[0187] Table 3 The data verification table below shows the results when the crack-inhibiting dopant is a composite addition or a combination of three powders: molybdenum powder, niobium powder, and tungsten powder.

[0188] Table 4 The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the process flow, formula ratio and technical principle of this application should be covered within the scope of protection of this application.

Claims

1. A process for eliminating printing cracks using GH3230 composite powder, characterized in that: Includes the following steps: S1: Prepare basic GH3230 powder, add crack-inhibiting dopant phase to the basic GH3230 powder for mixing and pretreatment, and obtain composite powder; S2: The composite powder is printed using SLM printing technology to obtain a printed component; S3: Perform post-forming heat treatment on the printed component; The crack-suppressing dopant phase is selected from one or more of molybdenum powder, niobium powder, and tungsten powder; wherein, when only molybdenum powder is used as the crack-suppressing dopant phase, the mass of molybdenum powder is 0.2-2.0% of the mass of the base GH3230 powder; when only niobium powder is used as the crack-suppressing dopant phase, the mass of niobium powder is 0.2-1.5% of the mass of the base GH3230 powder; when only tungsten powder is used as the crack-suppressing dopant phase, the mass of tungsten powder is 0.2-2.5% of the mass of the base GH3230 powder; when the crack-suppressing dopant phase is a composite addition or a combination of the above three powders, the total added mass is 0.2-2.5% of the mass of the base GH3230 powder.

2. The process method for eliminating printing cracks using GH3230 composite powder according to claim 1, characterized in that: The basic GH3230 powder in step S1 comprises the following components by mass fraction: C 0.05%-0.15%, Cr 20%-24%, Co 1%-5%, W 13%-15%, Mo 1%-3%, Al 0.2%-0.5%, Ti 0.01%-0.1%, Fe 0.01%-3%, La 0.005%-0.05%, B 0.01%-0.015%, Si 0.25%-0.75%, Mn 0.3%-1%, with the balance being Ni and unavoidable impurities.

3. The process method for eliminating printing cracks using GH3230 composite powder according to claim 1, characterized in that: In step S1, the particle size distribution of the composite powder is 15-53 μm, and the average particle size of the molybdenum powder, niobium powder and tungsten powder is less than 5 μm.

4. The process method for eliminating printing cracks using GH3230 composite powder according to claim 1, characterized in that: The method for preparing the basic GH3230 powder in step S1 is any one of the following: vacuum induction melting gas atomization process, electrode induction melting gas atomization process, and plasma rotating electrode process.

5. The process method for eliminating printing cracks using GH3230 composite powder according to claim 1, characterized in that: In step S1, the specific method of the mixed pretreatment is as follows: The basic GH3230 powder, molybdenum powder, niobium powder, and tungsten powder are placed in a vacuum drying oven at 80-120℃ and dried for 1-3 hours to remove the moisture and oil adsorbed on the powder surface and prevent porosity defects during the forming process. The powder was mixed using a high-speed mixer at a speed of 1300-1700 rpm. Each mixing session lasted 1-1.5 minutes. After mixing, the powder was cooled for 15-25 minutes. The mixing process was repeated 2-3 times until the powder was uniformly mixed and there was no obvious agglomeration. The final product was GH3230-Mo, GH3230-Nb, or GH3230-W single-doped composite powder, or GH3230-Mo-Nb-W mixed-doped composite powder.

6. The process method for eliminating printing cracks using GH3230 composite powder according to claim 1, characterized in that: In step S2, the process parameters of the SLM printing forming technology are: laser power 170-310W, scanning speed 650-1050mm / s, powder layer thickness 30-70μm, scanning spacing 70-130μm, scanning strategy is bidirectional staggered scanning, and the interlayer scanning angle is deflected by 60°; argon gas protection is used during the forming process, and the oxygen content is controlled below 0.1%.

7. The process method for eliminating printing cracks using GH3230 composite powder according to claim 1, characterized in that: The printed components are subjected to hot isostatic pressing (HIP) at 1080-1200℃ and 160±10MPa for 1-5 hours. Then, solution strengthening is performed by heating to 1160-1200℃ at a rate of 8-12℃ / min and holding for 1-4 hours to ensure that the alloying elements are fully dissolved and to eliminate microstructure segregation. Finally, argon gas is used for forced cooling.

8. The process method for eliminating printing cracks using GH3230 composite powder according to claim 4, characterized in that: The vacuum induction melting gas atomization process includes the following steps: Evacuate the vacuum induction furnace to 10°C. -2 -10 -3 The GH3230 raw material alloy is placed in a crucible and heated to 1540-1570 ℃ by medium-frequency induction heating. It is then held at this temperature for 5-20 minutes for refining. After the gas filling is completed, the temperature is lowered to 1400-1450 ℃. The molten metal flows into the atomizing nozzle through the bottom guide hole of the heat-insulating intermediate ladle. High-pressure argon gas of 3-6 MPa is introduced into the atomizing nozzle. The gas flow and the molten metal flow converge, breaking them into fine droplets of 10-150 μm. The droplets form spherical shapes due to surface tension during their fall. They are then rapidly cooled in an inert atmosphere. The powder is classified by a cyclone separator and falls into a collection tank. After cooling to room temperature, it is taken out and sieved to obtain basic GH3230 powder that meets the particle size specifications for laser additive manufacturing.

9. A process method for eliminating printing cracks using GH3230 composite powder according to claim 4, characterized in that: The electrode induction melting gas atomization process includes the following steps: The vacuum induction furnace body is evacuated to 10... -2 -10 -3 Under a protective atmosphere of 0.05-0.1 MPa, high-purity argon gas is introduced. A consumable electrode made from a GH3230 master alloy rod is clamped in a lifting and rotating mechanism and fed into a ring-shaped induction coil inside the furnace. Medium-frequency induction heating causes the electrode tip to consumable melt to 1540-1570 ℃. The electrode is held at this temperature for 5-20 minutes for refining. The heating power is adjusted to stabilize the molten pool temperature within the range required for atomization. The electrode descent rate is adjusted to form a stable droplet beam of molten metal, which falls vertically into the atomizing nozzle. High-pressure argon gas of 3-6 MPa is introduced into the atomizing nozzle. The gas flow converges with the molten metal droplet beam, breaking it into fine droplets of 10-150 μm. The powder is rapidly cooled in an inert atmosphere. After being classified by a cyclone separator, the powder falls into a collection tank, cools to room temperature, and is then sieved to obtain basic GH3230 powder conforming to the particle size specifications for laser additive manufacturing.

10. A process method for eliminating printing cracks using GH3230 composite powder according to claim 4, characterized in that: The plasma rotating electrode process includes the following steps: The vacuum induction furnace body is evacuated to 10. -2 -10 -3 Under a protective atmosphere of 0.05-0.1 MPa high-purity argon gas, the GH3230 master alloy rod is made into an electrode and clamped onto the high-speed rotating spindle of the equipment. The electrode tip is heated by plasma arc focusing to melt it to 1540-1570 ℃. It is then held at this temperature for 5-20 minutes for refining. The plasma power is adjusted to make the temperature of the melting area at the electrode tip suitable for atomization. The plasma power and electrode rotation speed are adjusted so that the molten metal is thrown out under centrifugal force to form fine droplets of 10-150 μm. The droplets form spherical shapes under the action of surface tension during the fall. They are then rapidly cooled in an inert atmosphere. The powder is separated by a sedimentation and classification device and falls into a collection tank. After cooling to room temperature, it is taken out and sieved to obtain basic GH3230 powder that meets the particle size specifications for additive manufacturing.

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