Method for 3D printing of high-strength GH4169 alloy through laser powder bed melting

Abstract

The invention belongs to the field of 3D printing nickel-based high-temperature alloy materials, and particularly provides a method for 3D printing of a high-strength GH4169 alloy through laser powder bed melting. The manufacturing process comprises the steps that GH4169 and WC alloy powder are mixed, fusion printing is conducted through a laser powder bed, and heat treatment is conducted. The GH4169 alloy powder comprises the following components in percentage by mass: less than or equal to 0.08% of C, 15.0-25.0% of Cr, 50.0-55.0% of Ni, 2-4% of Mo, 4-6% of Nb, 0.8-1.2% of Ti, 0.3-0.7% of Al and the balance of Fe. The adding proportion of the WC alloy powder is 2%-5%. The printing technology specifically comprises the steps that the laser power ranges from 200 W to 400 W, the scanning speed ranges from 600 mm / s to 1500 mm / s, the scanning distance ranges from 0.08 mm to 0.15 mm, and the layer thickness ranges from 80 micrometers to 120 micrometers. Compared with GH4169 without WC alloy powder, the strength and plasticity of the alloy at high temperature are improved at the same time, and the WC alloy powder has wide application prospects.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing of nickel-based alloy materials, and in particular to a method for laser powder bed fusion 3D printing of high-strength GH4169 alloy. Background Technology

[0002] GH4169 alloy manufactured using Laser Powder Bed Fusion (LPBF) technology offers advantages such as moldless forming, short production cycle, and high forming efficiency. Compared to other additive manufacturing technologies, LPBF enables the complete melting of metal powder under the action of a high-energy-density laser, thereby improving the density and surface quality of the formed parts.

[0003] Currently, the room temperature tensile strength of GH4169 alloy printed samples is typically 960~1000 MPa, and the yield strength is 640~680 MPa, which is insufficient. Solution treatment and double-aging heat treatment are usually required, but the entire heat treatment process typically exceeds 18 hours, which is time-consuming. Furthermore, the elongation decreases from approximately 40% to 20% after heat treatment, resulting in a significant reduction in plasticity. Even after standard post-heat treatment, the crystallographic anisotropy present in the finished microstructure may persist, affecting mechanical properties. Therefore, it is necessary to ensure the toughness of the printed samples while further improving the room temperature and high temperature strength of LPBF-formed GH4169 alloy.

[0004] In CN202510543498.4, 20-50 nm of La2Zr2O7 powder was added to GH4169 alloy powder and melt-formed using laser additive manufacturing. This composite strengthening phase significantly reduced the alloy grain size (refining it to 3-10 μm), improving room-temperature mechanical properties. However, the excessively fine grains and numerous grain boundaries resulted in insufficient high-temperature performance. CN202510765072.3, by increasing the homogenization annealing heat treatment time, combined with water quenching and two-stage aging, still failed to solve the problem of uneven grain size distribution after more than 18 hours, resulting in an excessive number of coarse columnar grains and a maximum elongation of only 22.4%.

[0005] Therefore, a laser powder bed fusion 3D printing method is needed to improve the room temperature and high temperature strength and elongation of GH4169 alloy and ensure uniform grain size distribution. Summary of the Invention

[0006] Currently, when GH4169 alloy is industrially prepared using laser powder bed fusion technology, it results in a columnar grain structure with strong anisotropy and insufficient mechanical properties. Metal matrix composites exhibit extremely high hardness and brittleness, leading to high residual stress, which in turn causes microcracks, porosity, elemental segregation, and poor mechanical properties. Normally printed samples lack sufficient strength, and heat-treated samples exhibit insufficient plasticity in some applications. To address the shortcomings of laser powder bed fusion technology in preparing GH4169 alloy, this invention provides a method for laser powder bed fusion 3D printing of high-strength GH4169 alloy. This method involves adding WC alloy powder to the GH4169 alloy raw material powder and simultaneously alloying the GH4169 alloy powder and WC alloy powder in situ during the laser powder bed fusion process, thereby obtaining a GH4169 alloy material with high density and good mechanical properties.

[0007] To achieve the above objectives, the present invention adopts the following technical solution.

[0008] A method for laser powder bed fusion 3D printing of high-strength GH4169 alloy includes the following steps: Step 1: Prepare GH4169 powder and WC alloy powder raw materials; Step 2: GH4169 alloy powder and WC alloy mixed powder are melted together using a laser powder bed melting method to obtain GH4169 alloy.

[0009] Furthermore, the mass of WC alloy powder is 2% to 5% of the total mass of the alloy mixed powder.

[0010] Furthermore, the particle size of GH4169 powder is 54~105μm, and the average particle size of WC alloy powder is 600nm.

[0011] Furthermore, the process parameters for laser powder bed melting include: laser power of 200~400W, scanning rate of 600~1500mm / s, scanning spacing of 0.08~0.15mm, and layer thickness of 80~120μm.

[0012] Furthermore, the GH4169 alloy powder comprises the following elements: C≤0.08%, Cr: 15.0~25.0%, Ni: 50.0~55.0%, Mo: 2~4%, Nb: 4~6%, Ti: 0.8~1.2%, Al: 0.3~0.7%, with the balance being Fe, where all percentages are by mass.

[0013] The GH4169 alloy has a density ≥99%, a tensile strength of 1019~1365MPa, a yield strength of 695~953MPa, and an elongation of 30.8~35.2%; at 650℃, the GH4169 alloy has a tensile strength of 897~1265MPa, a yield strength of 625~854MPa, and an elongation of 28.1~36.9%.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0015] When manufacturing high-temperature alloys using traditional manufacturing techniques, the addition of reinforcing phases such as WC can lead to extremely high hardness and brittleness, high residual stress, cracking at the reinforcing phase / matrix interface, and uneven distribution of the reinforcing phase. These problems can affect the mechanical properties of the manufactured parts. Additive manufacturing processes can produce more uniform and finer precipitates in the matrix, thereby significantly improving the properties of the metal. In this invention, WC, a nanoscale metal ceramic material with better compatibility with GH4169, is selected as the reinforcing phase.

[0016] In the strengthening of GH4169 alloy, the high melting point of W (3422℃) makes it difficult to disperse uniformly in conventional melting processes, and elemental segregation easily leads to uneven microstructure. However, WC-reinforced GH4169 materials prepared by LPBF technology can fully utilize its process characteristics to achieve efficient retention and strengthening of WC. Rapid solidification of the molten pool can inhibit the agglomeration and growth of WC particles, achieving a uniform distribution of nano- or submicron-sized WC in the matrix. At the same time, some WC decomposes, leading to the solid solution of high-melting-point element W and the precipitation of in-situ (Ti, Nb)C, which together with the undissolved WC particles form a composite strengthening phase. On the one hand, WC particles hinder dislocation movement through the Orowan ring mechanism; on the other hand, the in-situ generated (Nb, Ti)C can act as a heterogeneous nucleation core to refine the grains. Both work synergistically to improve the material's strength and high-temperature stability.

[0017] During the solidification of WC-reinforced GH4169 material in the molten pool, the solute concentration varies due to the addition of atoms to the γ-matrix. If the liquidus temperature is higher than the actual solidification temperature, a wider compositionally supercooled zone (CSZ) is generated to promote nucleation. The growth limiting factor Q quantifies the development rate of the CSZ, and is expressed as: .

[0018] Where m is the slope of the liquid curve, k is the solute distribution coefficient, and C0 is the solute concentration. According to the W-Ni binary phase diagram, the Q value of W in nickel alloys is 0.3K, which means that due to its low Q value, the structural undercooling is limited by WC. Meanwhile, grain refinement also originates from in-situ (Ti, Nb)C precipitation, and the interfacial energy for heterogeneous nucleation is given by the following formula: .

[0019] Where r, ΔFV, γ, and θ represent the nucleus radius, free energy per unit volume, interfacial energy, and wetting angle, respectively. It can be observed that nucleation is hindered at high wetting angles and large interfacial energies. The interface between (Ti,Nb)C and the matrix is ​​almost coherent, and the precipitates are at the nanoscale. Therefore, they will become ideal nucleation sites in the melt pool, thus increasing the number of nucleation sites per unit time.

[0020] Generally, excessive grain refinement affects high-temperature performance. At high temperatures, the reduced resistance to grain boundary slip leads to a decrease in overall mechanical properties. Therefore, we controlled the added WC content to below 5% and the grain size to 10-20 μm. By retaining some coarse columnar grains and reducing the number of grain boundaries, the material exhibits a bimodal structure of fine equiaxed grains and coarse columnar grains, achieving synergistic strengthening through multiple mechanisms. This improves both room-temperature and high-temperature mechanical properties.

[0021] In the LPBF printing process of GH4169, high Nb segregation in the liquid phase produces continuous long Laves. However, with the addition of WC phase to GH4169, the precipitation temperature of the Laves phase decreases with increasing WC content, resulting in insufficient precipitation time. Secondly, at the start of composite solidification, Nb / Ti elements in the liquid are consumed by C, forming (Nb, Ti)C. Therefore, the Laves phase is difficult to precipitate in the interdendritic region, reducing harmful phases in the alloy and thus improving its strength, elongation, and high-temperature mechanical properties. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be further described below.

[0023] Figure 1 The figure shows the mechanical properties of GH4169 alloys with different WC contents at room temperature (25℃).

[0024] Figure 2 The figure shows the high-temperature mechanical properties of GH4169 alloys with different WC contents at 650℃.

[0025] Figure 3 This is a SEM image of the precipitate from Example 7 of the present invention. Detailed Implementation

[0026] The present invention is further illustrated below with reference to the specification and embodiments, making its technical content clearer and easier to understand. The present invention can be embodied in many different embodiments, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0027] A method for laser powder bed fusion 3D printing of high-strength GH4169 alloy includes the following steps: Step 1: Prepare GH4169 powder and WC alloy powder raw materials. The particle size of GH4169 powder is 54~105μm, and the average particle size of WC alloy powder is 600nm. GH4169 alloy powder includes the following elements: C≤0.08%, Cr: 15.0~25.0%, Ni: 50.0~55.0%, Mo: 2~4%, Nb: 4~6%, Ti: 0.8~1.2%, Al: 0.3~0.7%, with the balance being Fe. All percentages are by mass. Step 2: GH4169 alloy powder and WC alloy mixed powder are melted together using a laser powder bed melting method to obtain GH4169 alloy; wherein, the mass of WC alloy powder is 2%~5% of the total mass of the alloy mixed powder; the process parameters for laser powder bed melting include: laser power of 200~400W, scanning rate of 600~1500mm / s, scanning spacing of 0.08~0.15mm, and layer thickness of 80~120μm.

[0028] The GH4169 alloy has a density ≥99%, a tensile strength of 1019~1365MPa, a yield strength of 695~953MPa, and an elongation of 30.8~35.2%; at 650℃, the GH4169 alloy has a tensile strength of 897~1265MPa, a yield strength of 625~854MPa, and an elongation of 28.1~36.9%.

[0029] Example 1.

[0030] The alloy powders GH4169 and WC, with the alloy element contents shown in Table 1, were used in a mass ratio of 98:2. The particle size of the GH4169 alloy powder was 54~105μm, and the particle size of the WC alloy powder was 600nm. GH4169 alloy powder and WC alloy powder were mixed. 316L steel balls with a diameter of 2mm were placed in a stainless steel ball mill jar. The mixed powder was then placed in the stainless steel ball mill jar for ball milling. The mixed powder obtained after ball milling is placed in a vacuum drying oven to obtain the dried mixed powder, which is the nickel-based alloy mixed powder material for laser powder bed melting and forming; GH4169 alloy was selected as the printing substrate. The surface was sanded to expose a flat and bright upper surface. After sanding, it was cleaned and dried with ethanol, and then placed in a laser powder bed melting and forming equipment. The laser power for laser powder bed melting was set to 200W, the scanning rate to 600mm / s, the scanning spacing to 0.08mm, and the layer thickness to 80μm. After printing, the substrate is removed from the equipment. After the substrate temperature drops to room temperature, the substrate is separated from the formed part by wire cutting to obtain a nickel-based alloy block without macroscopic cracks, namely GH4169 alloy.

[0031] The nickel-based alloy formed part of Example 1 has a tensile strength of 1098.1 MPa, a yield strength of 751.3 MPa, an elongation of 32.2%, and a density of 99.8%. The formed part has a tensile strength of 998.1 MPa, a yield strength of 651.3 MPa, an elongation of 34.2%, and a density of 99.8% at 650°C.

[0032] Example 2.

[0033] The alloy powders used, GH4169 and WC, have the alloy element contents shown in Table 1, and their mass ratio is 98:2. The particle size of the GH4169 alloy powder is 54~105μm, and the particle size of the pure metal WC powder is 600nm. GH4169 alloy powder and WC alloy powder were mixed. 316L steel balls with a diameter of 2mm were placed in a stainless steel ball mill jar. The mixed powder was then placed in the stainless steel ball mill jar for ball milling. The mixed powder obtained after ball milling is placed in a vacuum drying oven to obtain the dried mixed powder, which is the nickel-based alloy mixed powder material for laser powder bed melting and forming; GH4169 alloy was selected as the printing substrate. The surface was sanded to expose a flat and bright upper surface. After sanding, it was cleaned and dried with ethanol, and then placed in a laser powder bed melting and forming equipment. The laser power for laser powder bed melting was set to 300W, the scanning rate to 1050mm / s, the scanning interval to 0.12mm, and the layer thickness to 100μm. After printing is completed, the substrate is removed from the equipment. After the substrate temperature drops to room temperature, the substrate is separated from the molded part by wire cutting to obtain a nickel-based alloy block without macroscopic cracks.

[0034] The nickel-based alloy formed part of Example 2 has a tensile strength of 1089.6 MPa, a yield strength of 745.5 MPa, an elongation of 31.6%, and a density of 99.5%. The formed part has a tensile strength of 989.6 MPa, a yield strength of 648.5 MPa, an elongation of 34.6%, and a density of 99.5% at 650°C.

[0035] Example 3.

[0036] The alloy powders used, GH4169 and WC, have the alloy element contents shown in Table 1, and their mass ratio is 98:2. The particle size of the GH4169 alloy powder is 54~105μm, and the particle size of the pure metal WC powder is 600nm. GH4169 alloy powder and WC alloy powder were mixed. 316L steel balls with a diameter of 2mm were placed in a stainless steel ball mill jar. The mixed powder was then placed in the stainless steel ball mill jar for ball milling. The mixed powder obtained after ball milling is placed in a vacuum drying oven to obtain the dried mixed powder, which is the nickel-based alloy mixed powder material for laser powder bed melting and forming; GH4169 alloy was selected as the printing substrate. The surface was sanded to expose a flat and bright upper surface. After sanding, it was cleaned and dried with ethanol, and then placed in a laser powder bed melting and forming equipment. The laser power for laser powder bed melting was set to 400W, the scanning rate to 1500mm / s, the scanning spacing to 0.15mm, and the layer thickness to 120μm. After printing is completed, the substrate is removed from the equipment. After the substrate temperature drops to room temperature, the substrate is separated from the molded part by wire cutting to obtain a nickel-based alloy block without macroscopic cracks.

[0037] The nickel-based alloy formed part of Example 3 has a tensile strength of 1101.3 MPa, a yield strength of 749.5 MPa, an elongation of 32.1%, and a density of 99.6%. The formed part has a tensile strength of 1001.3 MPa, a yield strength of 649.5 MPa, an elongation of 35.1%, and a density of 99.6% at 650°C.

[0038] Example 4.

[0039] GH4169 alloy powder and WC alloy powder, with alloy element contents as shown in Table 1, were used in a mass ratio of 97:3. The particle size of the GH4169 alloy powder was 54~105μm, and the particle size of the WC alloy powder was 600nm. GH4169 alloy powder and WC alloy powder were mixed. 316L steel balls with a diameter of 2mm were placed in a stainless steel ball mill jar. The mixed powder was then placed in the stainless steel ball mill jar for ball milling. The mixed powder obtained after ball milling is placed in a vacuum drying oven to obtain the dried mixed powder, which is the nickel-based alloy mixed powder material for laser powder bed melting and forming; GH4169 alloy was selected as the printing substrate. The surface was sanded to expose a flat and bright upper surface. After sanding, it was cleaned and dried with ethanol, and then placed in a laser powder bed melting and forming equipment. The laser power for laser powder bed melting was set to 200W, the scanning rate to 600mm / s, the scanning spacing to 0.08mm, and the layer thickness to 80μm. After printing is completed, the substrate is removed from the equipment. After the substrate temperature drops to room temperature, the substrate is separated from the molded part by wire cutting to obtain a nickel-based alloy block without macroscopic cracks.

[0040] The nickel-based alloy formed part of Example 4 has a tensile strength of 1254.9 MPa, a yield strength of 830.1 MPa, an elongation of 34.3%, and a density of 99.9%. The formed part has a tensile strength of 1054.9 MPa, a yield strength of 730.1 MPa, an elongation of 36.3%, and a density of 99.9% at 650°C.

[0041] Example 5.

[0042] GH4169 alloy powder and WC alloy powder, with alloy element contents as shown in Table 1, were used in a mass ratio of 97:3. The particle size of the GH4169 alloy powder was 54~105μm, and the particle size of the WC alloy powder was 600nm. GH4169 alloy powder and WC alloy powder were mixed. 316L steel balls with a diameter of 2mm were placed in a stainless steel ball mill jar. The mixed powder was then placed in the stainless steel ball mill jar for ball milling. The mixed powder obtained after ball milling is placed in a vacuum drying oven to obtain the dried mixed powder, which is the nickel-based alloy mixed powder material for laser powder bed melting and forming; GH4169 alloy was selected as the printing substrate. The surface was sanded to expose a flat and bright upper surface. After sanding, it was cleaned and dried with ethanol, and then placed in a laser powder bed melting and forming equipment. The laser power for laser powder bed melting was set to 300W, the scanning rate to 1050mm / s, the scanning interval to 0.12mm, and the layer thickness to 100μm. After printing is completed, the substrate is removed from the equipment. After the substrate temperature drops to room temperature, the substrate is separated from the molded part by wire cutting to obtain a nickel-based alloy block without macroscopic cracks.

[0043] The nickel-based alloy formed part of Example 5 has a tensile strength of 1247.1 MPa, a yield strength of 822.4 MPa, an elongation of 33.7%, and a density of 99.8%. The formed part has a tensile strength of 1097.1 MPa, a yield strength of 722.4 MPa, an elongation of 36.7%, and a density of 99.8% at 650°C.

[0044] Example 6.

[0045] GH4169 alloy powder and WC alloy powder, with alloy element contents as shown in Table 1, were used in a mass ratio of 97:3. The particle size of the GH4169 alloy powder was 54~105μm, and the particle size of the WC alloy powder was 600nm. GH4169 alloy powder and WC alloy powder were mixed. 316L steel balls with a diameter of 2mm were placed in a stainless steel ball mill jar. The mixed powder was then placed in the stainless steel ball mill jar for ball milling. The mixed powder obtained after ball milling is placed in a vacuum drying oven to obtain the dried mixed powder, which is the nickel-based alloy mixed powder material for laser powder bed melting and forming; GH4169 alloy was selected as the printing substrate. The surface was sanded to expose a flat and bright upper surface. After sanding, it was cleaned and dried with ethanol, and then placed in a laser powder bed melting and forming equipment. The laser power for laser powder bed melting was set to 400W, the scanning rate to 1500mm / s, the scanning spacing to 0.15mm, and the layer thickness to 120μm. After printing is completed, the substrate is removed from the equipment. After the substrate temperature drops to room temperature, the substrate is separated from the molded part by wire cutting to obtain a nickel-based alloy block without macroscopic cracks.

[0046] The nickel-based alloy formed part of Example 6 has a tensile strength of 1193.5 MPa, a yield strength of 819.6 MPa, an elongation of 32.9%, and a density of 99.6%. The formed part has a tensile strength of 1123.5 MPa, a yield strength of 719.6 MPa, an elongation of 36.9%, and a density of 99.6% at 650°C.

[0047] Example 7.

[0048] GH4169 alloy powder and WC alloy powder, with alloy element contents as shown in Table 1, were used in a mass ratio of 95:5. The particle size of the GH4169 alloy powder was 54~105μm, and the particle size of the WC alloy powder was 600nm. GH4169 alloy powder and WC alloy powder were mixed. 316L steel balls with a diameter of 2mm were placed in a stainless steel ball mill jar. The mixed powder was then placed in the stainless steel ball mill jar for ball milling. The mixed powder obtained after ball milling is placed in a vacuum drying oven to obtain the dried mixed powder, which is the nickel-based alloy mixed powder material for laser powder bed melting and forming; GH4169 alloy was selected as the printing substrate. The surface was sanded to expose a flat and bright upper surface. After sanding, it was cleaned and dried with ethanol, and then placed in a laser powder bed melting and forming equipment. The laser power for laser powder bed melting was set to 200W, the scanning rate to 600mm / s, the scanning spacing to 0.08mm, and the layer thickness to 80μm. After printing is completed, the substrate is removed from the equipment. After the substrate temperature drops to room temperature, the substrate is separated from the molded part by wire cutting to obtain a nickel-based alloy block without macroscopic cracks.

[0049] The nickel-based alloy formed part of Example 7 has a tensile strength of 1300.2 MPa, a yield strength of 925.6 MPa, an elongation of 35.2%, and a density of 99.7%. The formed part has a tensile strength of 1200.2 MPa, a yield strength of 825.6 MPa, an elongation of 35.4%, and a density of 99.7% at 650°C.

[0050] Example 8.

[0051] GH4169 alloy powder and WC alloy powder, with alloy element contents as shown in Table 1, were used in a mass ratio of 95:5. The particle size of the GH4169 alloy powder was 54~105μm, and the particle size of the WC alloy powder was 600nm. GH4169 alloy powder and WC alloy powder were mixed. 316L steel balls with a diameter of 2mm were placed in a stainless steel ball mill jar. The mixed powder was then placed in the stainless steel ball mill jar for ball milling. The mixed powder obtained after ball milling is placed in a vacuum drying oven to obtain the dried mixed powder, which is the nickel-based alloy mixed powder material for laser powder bed melting and forming; GH4169 alloy was selected as the printing substrate. The surface was sanded to expose a flat and bright upper surface. After sanding, it was cleaned and dried with ethanol, and then placed in a laser powder bed melting and forming equipment. The laser power for laser powder bed melting was set to 300W, the scanning rate to 1050mm / s, the scanning interval to 0.12mm, and the layer thickness to 100μm. After printing is completed, the substrate is removed from the equipment. After the substrate temperature drops to room temperature, the substrate is separated from the molded part by wire cutting to obtain a nickel-based alloy block without macroscopic cracks.

[0052] The nickel-based alloy formed part of Example 8 has a tensile strength of 1365.1 MPa, a yield strength of 953.7 MPa, an elongation of 34.4%, and a density of 99.7%. The formed part has a tensile strength of 1265.1 MPa, a yield strength of 853.7 MPa, an elongation of 35.4%, and a density of 99.7% at 650°C.

[0053] Example 9.

[0054] GH4169 alloy powder and WC alloy powder, with alloy element contents as shown in Table 1, were used in a mass ratio of 95:5. The particle size of the GH4169 alloy powder was 54~105μm, and the particle size of the WC alloy powder was 600nm. GH4169 alloy powder and WC alloy powder were mixed. 316L steel balls with a diameter of 2mm were placed in a stainless steel ball mill jar. The mixed powder was then placed in the stainless steel ball mill jar for ball milling. The mixed powder obtained after ball milling is placed in a vacuum drying oven to obtain the dried mixed powder, which is the nickel-based alloy mixed powder material for laser powder bed melting and forming; GH4169 alloy was selected as the printing substrate. The surface was sanded to expose a flat and bright upper surface. After sanding, it was cleaned and dried with ethanol, and then placed in a laser powder bed melting and forming equipment. The laser power for laser powder bed melting was set to 400W, the scanning rate to 1500mm / s, the scanning spacing to 0.15mm, and the layer thickness to 120μm. After printing is completed, the substrate is removed from the equipment. After the substrate temperature drops to room temperature, the substrate is separated from the molded part by wire cutting to obtain a nickel-based alloy block without macroscopic cracks.

[0055] The nickel-based alloy formed part of Example 9 has a tensile strength of 1321.6 MPa, a yield strength of 939.2 MPa, an elongation of 33.9%, and a density of 99.5%. The formed part has a tensile strength of 1221.6 MPa, a yield strength of 839.2 MPa, an elongation of 35.9%, and a density of 99.5% at 650°C.

[0056] Comparative Example 1.

[0057] Commercial GH4169 alloy powder with alloy element content as shown in Table 1 and a particle size of 54~105μm was used. GH4169 alloy was selected as the printing substrate. The surface was polished with sandpaper to expose a flat and bright upper surface. After polishing, it was cleaned and dried with ethanol and then placed in a laser powder bed melting and forming equipment. The laser power of the laser powder bed melting and forming equipment was set to 200W, the scanning rate was 600mm / s, the scanning spacing was 0.08mm, and the layer thickness was 80μm. After printing is completed, the substrate is removed from the equipment. After the substrate temperature drops to room temperature, the substrate is separated from the molded part by wire cutting to obtain a nickel-based alloy block without macroscopic cracks.

[0058] The nickel-based alloy formed part of Comparative Example 1 has a tensile strength of 1039.8 MPa, a yield strength of 695.6 MPa, an elongation of 31.4%, and a density of 99.2%. The formed part has a tensile strength of 917.5 MPa, a yield strength of 625.9 MPa, an elongation of 33.4%, and a density of 99.2% at 650℃.

[0059] Comparative Example 2.

[0060] The alloy powders used were GH4169 and WC, with the alloy element contents shown in Table 1, and their mass ratio was 93:7. The particle size of the GH4169 alloy powder was 54~105μm, and the particle size of the WC alloy powder was 600nm. GH4169 alloy powder and WC alloy powder were mixed. 316L steel balls with a diameter of 2mm were placed in a stainless steel ball mill jar. The mixed powder was then placed in the stainless steel ball mill jar for ball milling. The mixed powder obtained after ball milling is placed in a vacuum drying oven to obtain the dried mixed powder, which is the nickel-based alloy mixed powder material for laser powder bed melting and forming; GH4169 alloy was selected as the printing substrate. The surface was sanded to expose a flat and bright upper surface. After sanding, it was cleaned and dried with ethanol, and then placed in a laser powder bed melting and forming equipment. The laser power for laser powder bed melting was set to 200W, the scanning rate to 600mm / s, the scanning spacing to 0.08mm, and the layer thickness to 80μm. After printing is completed, the substrate is removed from the equipment. After the substrate temperature drops to room temperature, the substrate is separated from the molded part by wire cutting to obtain a nickel-based alloy block without macroscopic cracks.

[0061] In Comparative Example 2, the nickel-based alloy formed part has a tensile strength of 1019.5 MPa, a yield strength of 743.1 MPa, an elongation of 30.8%, and a density of 99.1%. The formed part has a tensile strength of 897.0 MPa, a yield strength of 657.4 MPa, an elongation of 28.1%, and a density of 99.1% at 650℃.

[0062] Table 1. Composition of GH4169 alloy powder (mass fraction).

[0063] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for laser powder bed fusion 3D printing of high-strength GH4169 alloy, characterized in that, Includes the following steps: Step 1: Prepare GH4169 powder and WC alloy powder raw materials; Step 2: GH4169 alloy powder and WC alloy mixed powder are melted together using a laser powder bed melting method to obtain GH4169 alloy.

2. The method for laser powder bed fusion 3D printing of high-strength GH4169 alloy according to claim 1, characterized in that, The mass of the WC alloy powder is 2% to 5% of the total mass of the alloy mixed powder.

3. The method for laser powder bed fusion 3D printing of high-strength GH4169 alloy according to claim 1, characterized in that, The particle size of the GH4169 powder is 54~105μm, and the average particle size of the WC alloy powder is 600nm.

4. The method for laser powder bed fusion 3D printing of high-strength GH4169 alloy according to claim 1, characterized in that, The process parameters for laser powder bed melting include: laser power of 200~400W, scanning rate of 600~1500mm / s, scanning spacing of 0.08~0.15mm, and layer thickness of 80~120μm.

5. The method for laser powder bed fusion 3D printing of high-strength GH4169 alloy according to claim 1, characterized in that, GH4169 alloy powder contains the following elements: C≤0.08%, Cr: 15.0~25.0%, Ni: 50.0~55.0%, Mo: 2~4%, Nb: 4~6%, Ti: 0.8~1.2%, Al: 0.3~0.7%, with the balance being Fe. All percentages are by mass.

6. A GH4169 alloy prepared by the laser powder bed fusion 3D printing method according to any one of claims 1-5, characterized in that, The GH4169 alloy has a density ≥99%, a tensile strength of 1019~1365MPa, a yield strength of 695~953MPa, and an elongation of 30.8~35.2%; at 650℃, the GH4169 alloy has a tensile strength of 897~1265MPa, a yield strength of 625~854MPa, and an elongation of 28.1~36.9%.

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