GH4169 alloy and additive manufacturing method and application thereof

Abstract

The invention belongs to the technical field of alloy manufacturing, and relates to a GH4169 alloy and an additive manufacturing method and application thereof, and the additive manufacturing method at least comprises the steps of alloy powder blending, selective laser melting forming, solid solution heat treatment and aging heat treatment which are sequentially carried out; wherein the solid solution temperature of the solid solution heat treatment is greater than or equal to 1080 DEG C, and the cooling speed is greater than or equal to 400 DEG C / min; the aging heat treatment comprises first-step aging and second-step aging which are sequentially carried out, and the temperature of the first-step aging is greater than or equal to 735 DEG C. The heat treatment process is simplified, the solid solution temperature is increased, the cooling speed is increased, the anisotropy of the additive manufacturing GH4169 alloy is effectively improved, meanwhile, material softening caused by high-temperature solid solution is compensated by improving the aging heat treatment system and the aging strengthening effect, and finally the comprehensive mechanical property of the additive manufacturing GH4169 alloy is effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of alloy manufacturing technology, and relates to a GH4169 alloy, and more particularly to a GH4169 alloy and its additive manufacturing method and application. Background Technology

[0002] Metal additive manufacturing technology uses high-energy beams such as lasers, electron beams, or electric arcs as heat sources to achieve precise layer-by-layer deposition of materials based on three-dimensional digital models. It can directly form high-performance, large, and complex metal components, achieving integrated net-shape forming of materials and structures. In recent years, it has been increasingly widely used in high-end manufacturing fields such as aerospace and energy. Among them, GH4169 nickel-based superalloy, due to its excellent high-temperature mechanical properties even at an operating temperature of approximately 650℃, has become an important material for additive manufacturing research and application, and its additively manufactured components have been successfully engineered and promoted.

[0003] However, due to the high temperature gradient and rapid solidification behavior caused by the extremely high cooling rate during additive manufacturing, GH4169 alloy is prone to forming a non-equilibrium solidification structure, characterized by small grain size, high residual stress level, insufficient high-temperature plasticity, and significant differences in microstructure and properties between the fabrication direction and perpendicular to the fabrication direction. Therefore, effective control of microstructure and mechanical properties must be achieved through subsequent heat treatment processes. In its original deposited state, GH4169 high-temperature alloy is mainly composed of fine columnar crystals, exhibiting obvious anisotropic microstructure, high residual stress, and accompanied by microscopic defects such as brittle Laves phase and porosity. Compared to traditional forming processes, the extremely high cooling rate in additive manufacturing suppresses the precipitation of the δ phase and the main strengthening phases γ″ and γ′, resulting in insufficient mechanical properties of the alloy at high temperatures and exhibiting significant anisotropy. Therefore, high-temperature heat treatment is necessary to promote microstructure homogenization and induce appropriate grain growth, thereby improving its high-temperature plasticity. Subsequently, solution heat treatment is used to induce the precipitation of an appropriate amount of δ phase at grain boundaries and within the grains to enhance grain boundary bonding strength. Finally, a two-stage aging treatment is employed to allow the γ″ and γ′ strengthening phases to precipitate in a dispersed form and distribute uniformly in the matrix, thereby significantly improving the overall strength of the alloy.

[0004] In practical applications, traditional heat treatment methods face multiple problems. On the one hand, the pinning of the δ phase at the original grain boundaries hinders grain growth. The complete dissolution temperature of the δ phase is 1020℃, but a longer holding time is required at this temperature to completely dissolve the δ phase. In the homogenization heat treatment for microstructure recrystallization in traditional forming methods (casting, forging, etc.), the homogenization temperature of the casting is generally 1095℃ for 2 hours. Applying this method to the laser selective melting forming of GH4169 alloy can completely dissolve the δ phase at the grain boundaries to promote grain growth, but due to factors such as fluctuations in the chemical composition of GH4169 alloy powder and different laser selective melting forming process parameters, incomplete recrystallization often occurs, resulting in low high-temperature plasticity of the alloy.

[0005] On the other hand, the solution heat treatment of GH4169 alloy castings and forgings involves holding at 950-980℃ for 1 hour, and the aging heat treatment involves holding at 720℃ for 8 hours followed by furnace cooling to 620℃ for 8 hours. When using the traditional "homogenization + solution + aging" heat treatment system, not only will the microstructure not be completely transformed after homogenization due to fluctuations in the chemical composition of GH4169 alloy and differences in forming parameters, but it is also necessary to further regulate the strengthening phases δ, γ″, and γ′ through solution and aging, making the heat treatment process cumbersome. Moreover, the high-temperature tensile plasticity of GH4169 alloy after treatment is poor, and the creep time and elongation still cannot reach the level of castings and forgings.

[0006] Currently, the conventional solution is to increase the solution temperature to accelerate the dissolution of the δ phase, thereby dissolving the δ phase pinning the grain boundaries and promoting grain growth under high-temperature solution treatment, thus improving high-temperature plasticity. However, excessively high solution temperatures and excessively long holding times can lead to excessive grain growth, resulting in reduced strength. Furthermore, depending on the fluctuation of the chemical composition of the raw materials, excessively high solution temperatures can easily lead to over-solution in additive manufacturing of GH4169 alloy, severely reducing the material strength. The age-hardening effect of traditional aging processes is insufficient to improve the low strength problem caused by over-solution.

[0007] It is evident that existing heat treatment technologies for additive manufacturing GH4169 alloy suffer from problems such as cumbersome processes, large performance fluctuations, difficulty in balancing strength and plasticity, and failure to meet key performance standards. There is an urgent need to improve the heat treatment scheme to solve the aforementioned industry pain points. Summary of the Invention

[0008] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a GH4169 alloy and its additive manufacturing method and application, and to solve the problems of cumbersome process, large performance fluctuation, difficulty in balancing strength and plasticity, and failure to meet key performance standards in the existing additive manufacturing heat treatment technology for GH4169 alloy.

[0009] To achieve this objective, the present invention employs the following technical solution:

[0010] In a first aspect, the present invention provides an additive manufacturing method for GH4169 alloy, comprising at least the following steps in sequence: alloy powder preparation, laser selective melting forming, solution heat treatment, and aging heat treatment.

[0011] The solution heat treatment has a solution temperature ≥1080℃ and a cooling rate ≥400℃ / min; the aging heat treatment includes a first aging step and a second aging step performed sequentially, and the aging temperature of the first aging step is ≥735℃.

[0012] The additive manufacturing process proposed in this invention simplifies the traditional "homogenization treatment + solution heat treatment" into a one-step high-temperature heat treatment by optimizing the solution heat treatment regime. This ensures sufficient recrystallization while promoting the precipitation of grain boundary strengthening phases and effectively inhibiting excessive grain growth. By increasing the solution temperature and cooling rate, this process significantly improves the microstructure anisotropy of the additive-manufactured GH4169 alloy. Simultaneously, by adjusting the aging heat treatment process, the age-strengthening effect is enhanced, effectively compensating for the material softening caused by high-temperature solution treatment. Ultimately, the above synergistic optimization strategy significantly improves the overall mechanical properties of the additive-manufactured GH4169 alloy.

[0013] Preferably, the elemental composition of the alloy powder, by mass fraction, includes: Ni 50-55wt%, Cr 17-21wt%, Nb 4.75-5.50wt%, Mo 2.8-3.3wt%, Ti 0.65-1.15wt%, Al 0.2-0.8wt%, with the balance being Fe.

[0014] Preferably, the elemental composition of the alloy powder, by mass fraction, further includes: Co ≤ 1.00 wt%, Cu ≤ 0.30 wt%, C 0.035-0.055 wt%, Si ≤ 0.35 wt%, Mn ≤ 0.35 wt%, P ≤ 0.015 wt%, S ≤ 0.015 wt%, B ≤ 0.006 wt%, O ≤ 0.025 wt%, N ≤ 0.025 wt%, and Mg ≤ 0.01 wt%.

[0015] Preferably, the laser selective melting forming includes: after spreading powder, filling the forming environment with a protective gas, and performing laser scanning using a strip scanning method.

[0016] Preferably, the thickness of the powder coating is 60-80 μm.

[0017] Preferably, the protective gas includes argon and / or helium, and the oxygen content in the forming environment is controlled to be ≤0.05%.

[0018] Preferably, the diameter of the laser scanning spot is 75-85 μm.

[0019] Preferably, the laser power of the laser scanning is 300-340W.

[0020] Preferably, the scanning speed of the laser scanning is 1000-1100 mm / s.

[0021] Preferably, during the laser scanning process, the scanning directions of adjacent laser lines are opposite, and the scanning distance between adjacent laser lines is 0.09-0.11 mm.

[0022] Preferably, the width of the strip scan is 7-10 mm.

[0023] Preferably, the strip spacing of the strip scan is 0.05-0.08 mm.

[0024] Preferably, during the strip scanning process, the rotation angle of the strips between layers is 60°-70°.

[0025] Preferably, the solution heat treatment is carried out in a vacuum heat treatment furnace, and the vacuum degree inside the furnace is ≤1 Pa.

[0026] Preferably, the solution temperature of the solution heat treatment is 1110-1120℃.

[0027] Preferably, the heat treatment holding time is 1-2 hours.

[0028] Preferably, the aging heat treatment is carried out in a vacuum heat treatment furnace, and the vacuum degree inside the furnace is ≤1 Pa.

[0029] Preferably, the aging temperature of the first aging step is 735-750℃.

[0030] Preferably, the time required for the first step of the aging process is 6-8 hours.

[0031] Preferably, the aging temperature in the second step is 620-635℃.

[0032] Preferably, the aging time for the second step is 4-6 hours.

[0033] Preferably, furnace cooling is performed between the first aging step and the second aging step, and the furnace cooling time is 1-3 hours.

[0034] Preferably, after the second step of aging is completed, argon gas is used for cooling.

[0035] In a second aspect, the present invention provides a GH4169 alloy, which is prepared by the additive manufacturing method described in the first aspect.

[0036] Thirdly, the present invention provides an application of the GH4169 alloy as described in the second aspect, wherein the GH4169 alloy is used to manufacture large and complex metal components.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The additive manufacturing process proposed in this invention simplifies the traditional "homogenization treatment + solution heat treatment" into a one-step high-temperature heat treatment by optimizing the solution heat treatment regime. This ensures sufficient recrystallization while promoting the precipitation of grain boundary strengthening phases and effectively inhibiting excessive grain growth. By increasing the solution temperature and cooling rate, this process significantly improves the microstructure anisotropy of the additive-manufactured GH4169 alloy. Simultaneously, by adjusting the aging heat treatment process, the age-strengthening effect is enhanced, effectively compensating for the material softening caused by high-temperature solution treatment. Ultimately, the above synergistic optimization strategy significantly improves the overall mechanical properties of the additive-manufactured GH4169 alloy. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the scanning method and the laser scanning trajectory inside the part in two adjacent scanning layers of the additive manufacturing method provided in Example 1. Detailed Implementation

[0040] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0041] One embodiment of the present invention provides an additive manufacturing method for GH4169 alloy, which includes at least the sequential processes of alloy powder preparation, laser selective melting forming, solution heat treatment, and aging heat treatment.

[0042] The solution heat treatment has a solution temperature ≥1080℃ and a cooling rate ≥400℃ / min; the aging heat treatment includes a first aging step and a second aging step performed sequentially, and the aging temperature of the first aging step is ≥735℃.

[0043] The additive manufacturing process proposed in this invention simplifies the traditional "homogenization treatment + solution heat treatment" into a one-step high-temperature heat treatment by optimizing the solution heat treatment regime. This ensures sufficient recrystallization while promoting the precipitation of grain boundary strengthening phases and effectively inhibiting excessive grain growth. By increasing the solution temperature and cooling rate, this process significantly improves the microstructure anisotropy of the additive-manufactured GH4169 alloy. Simultaneously, by adjusting the aging heat treatment process, the age-strengthening effect is enhanced, effectively compensating for the material softening caused by high-temperature solution treatment. Ultimately, the above synergistic optimization strategy significantly improves the overall mechanical properties of the additive-manufactured GH4169 alloy.

[0044] Specifically, this invention raises the solution temperature to above 1080℃, primarily to completely dissolve the δ phase in the microstructure. Traditional solution temperatures are too low, leading to incomplete dissolution of the δ phase. Furthermore, the precipitation of the δ phase consumes the precipitating elements of the γ″ phase during aging heat treatment, reducing the amount of γ″ phase precipitated in the alloy and thus adversely affecting the yield strength and tensile strength of the alloy. Simultaneously, this invention limits the cooling rate to no less than 400℃ / min, which will precipitate some δ phase. An appropriate amount of δ phase will pin grain boundaries, inhibiting excessive grain growth and thus reducing... Low-alloy steels are notch sensitive, and slow cooling during traditional homogenization heat treatment will precipitate more δ phase, thereby inhibiting the precipitation of γ″ phase and reducing the strength of the alloy. Furthermore, this invention raises the aging temperature of the first aging step to above 735℃, mainly to increase the precipitation of γ″ phase, because γ″ phase precipitates between 595-870℃, with its precipitation peak temperature range between 732-760℃, and γ″ phase has a large lattice mismatch degree, which plays an important role in improving the mechanical properties of the material such as hardness, tensile strength and fatigue life.

[0045] In some embodiments, the elemental composition of the alloy powder, by mass fraction, includes: Ni 50-55wt%, Cr 17-21wt%, Nb 4.75-5.50wt%, Mo 2.8-3.3wt%, Ti 0.65-1.15wt%, Al 0.2-0.8wt%, with the balance being Fe.

[0046] The Ni mass fraction is 50-55 wt%, for example, it can be 50 wt%, 50.5 wt%, 51 wt%, 51.5 wt%, 52 wt%, 52.5 wt%, 53 wt%, 53.5 wt%, 54 wt%, 54.5 wt%, or 55 wt%, and the Cr mass fraction is 17-21 wt%, for example, it can be 17 wt%, 17.5 wt%, 18 wt%, 18.5 wt%, 19 wt%, 19.5 wt%, 20 wt%, or 20.5 wt%. The mass fraction of Nb is 4.75-5.50 wt%, for example, it can be 4.75 wt%, 4.80 wt%, 4.85 wt%, 4.90 wt%, 4.95 wt%, 5.00 wt%, 5.05 wt%, 5.10 wt%, 5.15 wt%, 5.20 wt%, 5.25 wt%, 5.30 wt%, 5.35 wt%, 5.40 wt%, 5.45 wt%, or 5.50 wt%, and the mass fraction of Mo is 2.8- 3.3 wt%, for example, could be 2.8 wt%, 2.85 wt%, 2.9 wt%, 2.95 wt%, 3 wt%, 3.05 wt%, 3.1 wt%, 3.15 wt%, 3.2 wt%, 3.25 wt%, or 3.3 wt%, and the mass fraction of Ti is 0.65-1.15 wt%, for example, could be 0.65 wt%, 0.7 wt%, 0.75 wt%, 0.8 wt%, 0.85 wt%, 0.9 wt%, 0.95 wt%, 1 wt%. 1.05wt%, 1.1wt%, or 1.15wt%, with an Al mass fraction of 0.2-0.8wt%, for example, 0.2wt%, 0.25wt%, 0.3wt%, 0.35wt%, 0.4wt%, 0.45wt%, 0.5wt%, 0.55wt%, 0.6wt%, 0.65wt%, 0.7wt%, 0.75wt%, or 0.8wt%, but not limited to the listed values; other unlisted values ​​within this range also apply.

[0047] In some embodiments, the elemental composition of the alloy powder, by mass fraction, further includes: Co ≤ 1.00 wt%, Cu ≤ 0.30 wt%, C 0.035-0.055 wt%, Si ≤ 0.35 wt%, Mn ≤ 0.35 wt%, P ≤ 0.015 wt%, S ≤ 0.015 wt%, B ≤ 0.006 wt%, O ≤ 0.025 wt%, N ≤ 0.025 wt%, and Mg ≤ 0.01 wt%.

[0048] Wherein, the mass fraction of Co is ≤1.00wt%, for example, it can be 0.10wt%, 0.20wt%, 0.30wt%, 0.40wt%, 0.50wt%, 0.60wt%, 0.70wt%, 0.80wt%, 0.90wt%, or 1.00wt%; the mass fraction of Cu is ≤0.30wt%, for example, it can be 0.05wt%, 0.10wt%, 0.15wt%, 0.20wt%, 0.25wt%, or 0.30wt%; and the mass fraction of C is 0.035-0.055wt%, for example, it can be 0.035wt%, 0.040wt%, 0.04wt%, or 0.05wt%. The mass fractions of Si are ≤0.35wt%, for example, 0.05wt%, 0.10wt%, 0.15wt%, 0.20wt%, 0.25wt%, 0.30wt%, or 0.35wt%; the mass fractions of Mn are ≤0.35wt%, for example, 0.05wt%, 0.10wt%, 0.15wt%, 0.20wt%, 0.25wt%, 0.30wt%, or 0.35wt%; and the mass fractions of P are ≤0.015wt%, for example, 0.002wt%, 0.004wt%, or 0.006wt%. t%, 0.008wt%, 0.010wt%, 0.012wt%, 0.014wt% or 0.015wt%, S mass fraction ≤ 0.015wt%, for example, it can be 0.002wt%, 0.004wt%, 0.006wt%, 0.008wt%, 0.010wt%, 0.012wt%, 0.014wt% or 0.015wt%, B mass fraction ≤ 0.006wt%, for example, it can be 0.001wt%, 0.002wt%, 0.003wt%, 0.004wt%, 0.005wt% or 0.006wt%, O mass fraction The mass fraction of N is ≤0.025wt%, for example, it can be 0.005wt%, 0.010wt%, 0.015wt%, 0.020wt% or 0.025wt%, and the mass fraction of Mg is ≤0.01wt%, for example, it can be 0.005wt%, 0.010wt%, 0.015wt%, 0.020wt% or 0.025wt%, and the mass fraction of Mg is ≤0.01wt%, for example, it can be 0.002wt%, 0.004wt%, 0.006wt%, 0.008wt% or 0.01wt%, but it is not limited to the listed values. Other unlisted values ​​within this range also apply.

[0049] In some embodiments, the laser selective melting forming includes: after powder spreading, filling the forming environment with a protective gas, and performing laser scanning using a strip scanning method.

[0050] In some embodiments, the thickness of the powder coating is 60-80 μm, for example, it can be 60 μm, 62 μm, 64 μm, 66 μm, 68 μm, 70 μm, 72 μm, 74 μm, 76 μm, 78 μm or 80 μm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0051] In some embodiments, the protective gas includes argon and / or helium, and the oxygen content in the forming environment is controlled to be ≤0.05%, for example, 0.005%, 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045%, or 0.05%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0052] In some embodiments, the diameter of the laser scanning spot is 75-85 μm, for example, it can be 75 μm, 76 μm, 77 μm, 78 μm, 79 μm, 80 μm, 81 μm, 82 μm, 83 μm, 84 μm or 85 μm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0053] In some embodiments, the laser power of the laser scanning is 300-340W, for example, it can be 300W, 305W, 310W, 315W, 320W, 325W, 330W, 335W or 340W, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0054] In some embodiments, the scanning speed of the laser scan is 1000-1100 mm / s, for example, it can be 1000 mm / s, 1010 mm / s, 1020 mm / s, 1030 mm / s, 1040 mm / s, 1050 mm / s, 1060 mm / s, 1070 mm / s, 1080 mm / s, 1090 mm / s or 1100 mm / s, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0055] In some embodiments, during the laser scanning process, the scanning directions of adjacent laser lines are opposite, and the scanning distance between adjacent laser lines is 0.09-0.11 mm, for example, it can be 0.09 mm, 0.092 mm, 0.094 mm, 0.096 mm, 0.098 mm, 0.1 mm or 0.11 mm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0056] In some embodiments, the strip width of the strip scan is 7-10 mm, for example, it can be 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm or 10 mm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0057] In some embodiments, the strip spacing of the strip scan is 0.05-0.08 mm, for example, it can be 0.05 mm, 0.055 mm, 0.06 mm, 0.065 mm, 0.07 mm, 0.075 mm or 0.08 mm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0058] In some embodiments, during the strip scanning process, the rotation angle of the strips between layers is 60°-70°, for example, it can be 60°, 61°, 62°, 63°, 64°, 65°, 66°, 67°, 68°, 69° or 70°, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0059] In some embodiments, the solution heat treatment is carried out in a vacuum heat treatment furnace, and the vacuum degree inside the furnace is ≤1 Pa, for example, it can be 0.1 Pa, 0.2 Pa, 0.3 Pa, 0.4 Pa, 0.5 Pa, 0.6 Pa, 0.7 Pa, 0.8 Pa, 0.9 Pa or 1 Pa, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0060] In some embodiments, the solution temperature of the solution heat treatment is 1110-1120°C, for example, it can be 1110°C, 1111°C, 1112°C, 1113°C, 1114°C, 1115°C, 1116°C, 1117°C, 1118°C, 1119°C or 1120°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0061] In some embodiments, the holding time for the solution heat treatment is 1-2 hours, for example, it can be 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours or 2 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0062] In some embodiments, the aging heat treatment is carried out in a vacuum heat treatment furnace, and the vacuum degree inside the furnace is ≤1Pa, for example, it can be 0.1Pa, 0.2Pa, 0.3Pa, 0.4Pa, 0.5Pa, 0.6Pa, 0.7Pa, 0.8Pa, 0.9Pa or 1Pa, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0063] In some embodiments, the aging temperature of the first aging step is 735-750℃, for example, it can be 735℃, 736℃, 737℃, 738℃, 739℃, 740℃, 741℃, 742℃, 743℃, 744℃, 745℃, 746℃, 747℃, 748℃, 749℃ or 750℃, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0064] In some embodiments, the time for the first step of aging is 6-8 hours, for example, it can be 6 hours, 6.2 hours, 6.4 hours, 6.6 hours, 6.8 hours, 7 hours, 7.2 hours, 7.4 hours, 7.6 hours, 7.8 hours or 8 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0065] In some embodiments, the aging temperature of the second step is 620-635℃, for example, it can be 620℃, 621℃, 622℃, 623℃, 624℃, 625℃, 626℃, 627℃, 628℃, 629℃, 630℃, 631℃, 632℃, 633℃, 634℃ or 635℃, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0066] In some embodiments, the aging time of the second step is 4-6 hours, for example, it can be 4 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours, 5 hours, 5.2 hours, 5.4 hours, 5.6 hours, 5.8 hours or 6 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0067] In some embodiments, furnace cooling is performed between the first aging step and the second aging step, and the furnace cooling time is 1-3 hours, for example, it can be 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours or 3 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0068] In some embodiments, argon purging and cooling are performed after the second aging step is completed.

[0069] One embodiment of the present invention also provides a GH4169 alloy, which is obtained by the additive manufacturing method described in any of the above embodiments.

[0070] One embodiment of the present invention also provides an application of the GH4169 alloy described in any of the above embodiments, wherein the GH4169 alloy is used to manufacture large and complex metal components.

[0071] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0072] Example 1

[0073] This embodiment provides a GH4169 alloy and its additive manufacturing method, the additive manufacturing method including the following steps:

[0074] (1) Alloy powder: The elemental composition of the alloy powder, by mass fraction, includes: Ni 52wt%, Cr 18wt%, Nb 5.2wt%, Mo 3.1wt%, Ti 1.05wt%, Al 0.6wt%, Co 0.84wt%, Cu 0.26wt%, C 0.04wt%, Si 0.31wt%, Mn 0.28wt%, P 0.01wt%, S 0.012wt%, B 0.004wt%, O 0.02wt%, N 0.017wt%, Mg 0.006wt%, with the balance being Fe.

[0075] (2) Selective laser melting and forming: After the powder is laid (average thickness is 70 μm), argon gas is introduced into the forming environment to control the oxygen content in the forming environment to ≤0.05%. Then, laser scanning is performed by strip scanning. The spot diameter is set to 80 μm, the laser power is 320 W, and the scanning speed is 1050 mm / s. During the laser scanning process, the scanning directions of adjacent laser lines are opposite, and the scanning distance between adjacent laser lines is 0.1 mm. The strip width of the strip scanning is 8 mm, the strip spacing is 0.06 mm, and the rotation angle of the strip between layers is 67° to ensure that the laser lines of each layer do not repeat, and at the same time ensure the consistency of the cross-sectional structure along the powder laying direction and perpendicular to the powder laying direction. Figure 1 The scanning method and laser path inside the part are shown for two adjacent scanning layers (only one strip laser path is shown in the figure). The part is located in the forming chamber plane, and the part is divided into multiple scanning strips within the cross section of the forming section.

[0076] (3) Solution heat treatment: The vacuum degree inside the vacuum heat treatment furnace is evacuated to 0.8 Pa, the solution temperature is controlled at 1110℃, the holding time is 2h, and the cooling rate is 400℃ / min.

[0077] (4) Aging heat treatment: The vacuum degree inside the vacuum heat treatment furnace is evacuated to 0.8 Pa, and the first aging step and the second aging step are performed in sequence; wherein, the aging temperature of the first aging step is 735℃ and the aging time is 8h; the aging temperature of the second aging step is 620℃ and the aging time is 6h; furnace cooling is performed between the first aging step and the second aging step, and the furnace cooling time is 2h; after the second aging step is completed, argon gas is used for cooling.

[0078] Example 2

[0079] This embodiment provides a GH4169 alloy and its additive manufacturing method, the additive manufacturing method including the following steps:

[0080] (1) Alloy powder: The elemental composition of the alloy powder is the same as that in Example 1 according to mass fraction, so it will not be repeated here.

[0081] (2) Selective laser melting and forming: After powdering (average thickness of 60 μm), argon gas is introduced into the forming environment to control the oxygen content in the forming environment to ≤0.05%. Then, laser scanning is performed by strip scanning. The spot diameter is set to 75 μm, the laser power is 300 W, and the scanning speed is 1000 mm / s. During the laser scanning process, the scanning directions of adjacent laser lines are opposite, and the scanning distance between adjacent laser lines is 0.09 mm. The strip width of the strip scanning is 7 mm, the strip spacing is 0.05 mm, and the rotation angle of the strip between layers is 60° to ensure that the laser lines of each layer do not repeat, and at the same time ensure the consistency of the cross-sectional structure along the powdering direction and perpendicular to the powdering direction.

[0082] (3) Solution heat treatment: The vacuum degree inside the vacuum heat treatment furnace is evacuated to 1 Pa, the solution temperature is controlled at 1115℃, the holding time is 1.5h, and the cooling rate is 420℃ / min.

[0083] (4) Aging heat treatment: The vacuum degree inside the vacuum heat treatment furnace is evacuated to 1 Pa, and the first aging step and the second aging step are performed in sequence; wherein, the aging temperature of the first aging step is 740℃ and the aging time is 7h; the aging temperature of the second aging step is 628℃ and the aging time is 5h; furnace cooling is performed between the first aging step and the second aging step, and the furnace cooling time is 2h; after the second aging step is completed, argon gas is used for cooling.

[0084] Example 3

[0085] This embodiment provides a GH4169 alloy and its additive manufacturing method, the additive manufacturing method including the following steps:

[0086] (1) Alloy powder: The elemental composition of the alloy powder is the same as that in Example 1 according to mass fraction, so it will not be repeated here.

[0087] (2) Selective laser melting and forming: After the powder is laid (average thickness is 80μm), argon gas is introduced into the forming environment to control the oxygen content in the forming environment to ≤0.05%. Then, laser scanning is performed by strip scanning. The spot diameter is set to 85μm, the laser power is 340W, and the scanning speed is 1100mm / s. During the laser scanning process, the scanning directions of adjacent laser lines are opposite, and the scanning distance between adjacent laser lines is 0.11mm. The strip width of the strip scanning is 10mm, the strip spacing is 0.08mm, and the rotation angle of the strip between layers is 70° to ensure that the laser lines of each layer do not repeat, and at the same time ensure the consistency of the cross-sectional structure along the powder laying direction and perpendicular to the powder laying direction.

[0088] (3) Solution heat treatment: The vacuum degree inside the vacuum heat treatment furnace is evacuated to 1 Pa, the solution temperature is controlled at 1120℃, the holding time is 1h, and the cooling rate is 450℃ / min.

[0089] (4) Aging heat treatment: The vacuum degree inside the vacuum heat treatment furnace is evacuated to 1 Pa, and the first aging step and the second aging step are performed in sequence; wherein, the aging temperature of the first aging step is 750℃ and the aging time is 6h; the aging temperature of the second aging step is 635℃ and the aging time is 4h; the furnace is cooled between the first aging step and the second aging step, and the furnace cooling time is 2h; after the second aging step is completed, argon gas is used for cooling.

[0090] Example 4

[0091] This embodiment provides a GH4169 alloy and its additive manufacturing method. Except for changing the solution temperature of the solution heat treatment in step (3) to 1130℃, the other steps and conditions are the same as in embodiment 1, so they will not be repeated here.

[0092] Example 5

[0093] This embodiment provides a GH4169 alloy and its additive manufacturing method. Except for changing the solution temperature of the solution heat treatment in step (3) to 1080℃, the other steps and conditions are the same as in embodiment 1, so they will not be described in detail here.

[0094] Comparative Example 1

[0095] This comparative example provides a GH4169 alloy and its additive manufacturing method. Except for changing the solution temperature of the solution heat treatment in step (3) to 1050℃, the other steps and conditions are the same as in Example 1, so they will not be repeated here.

[0096] Comparative Example 2

[0097] This comparative example provides a GH4169 alloy and its additive manufacturing method. Except for changing the solution temperature of the solution heat treatment in step (3) to 980℃, the other steps and conditions are the same as in Example 1, so they will not be repeated here.

[0098] Comparative Example 3

[0099] This comparative example provides a GH4169 alloy and its additive manufacturing method. Except for changing the solution temperature of the solution heat treatment in step (3) to 950°C, the other steps and conditions are the same as in Example 1, so they will not be repeated here.

[0100] Comparative Example 4

[0101] This comparative example provides a GH4169 alloy and its additive manufacturing method. Except for changing the aging temperature of the first aging step in step (4) to 720°C, the other steps and conditions are the same as in Example 1, so they will not be repeated here.

[0102] Performance testing

[0103] The tensile properties of the GH4169 alloys obtained in Examples 1-5 and Comparative Examples 1-4 at room temperature (25°C) (see Tables 1 and 2 below), at high temperature (650°C), and at high temperature creep mechanical properties (see Tables 3 and 4 below) were tested respectively.

[0104] Table 1

[0105]

[0106] Table 2

[0107]

[0108] Table 3

[0109]

[0110] Table 4

[0111]

[0112] From Tables 1 to 4, we can see that:

[0113] (1) The room temperature tensile, high temperature tensile, and high temperature creep mechanical properties of the GH4169 alloys prepared in Examples 1, 4-5, and Comparative Examples 1-3 (corresponding to solution treatment temperatures of 950℃, 980℃, 1050℃, 1080℃, 1110℃, and 1130℃) were tested. With increasing solution temperature, both the room temperature and high temperature tensile strengths of the alloys gradually decreased, while the elongation increased accordingly. In terms of orientation, the transverse specimens generally exhibited higher strength than the longitudinal specimens, but their elongation was lower. The high temperature creep performance test results showed that within the solution temperature range of 950–1050℃, the creep life along both construction directions was insufficient to meet the technical requirements. When the solution temperature was increased to 1080℃ and above, the creep time in both the XY and Z directions met the technical standards, and the room temperature and high temperature tensile strengths and elongation also met the requirements. However, excessively high solution temperatures would further reduce the high temperature tensile strength of the alloys.

[0114] (2) The room temperature tensile, high temperature tensile, and high temperature creep mechanical property test results of the GH4169 alloy obtained in Example 1 and Comparative Example 4 (using two aging regimes, 735℃ / 8h + 620℃ / 6h and 720℃ / 8h + 620℃ / 6h respectively) show that increasing the first-step aging temperature helps to simultaneously improve the room temperature and high temperature yield strength and tensile strength of the alloy, and the increase in high temperature strength is more significant. Specifically, compared with Comparative Example 4, the room temperature tensile strength and yield strength of the alloy in Example 1 increased by about 5%, the high temperature tensile strength increased by about 7%, and the increase in high temperature yield strength was the most significant, reaching about 13%. The study further shows that under the traditional process conditions with a first-step aging temperature of 720℃, the room temperature yield strength and longitudinal high temperature yield strength of the alloy in both construction directions are unstable and difficult to meet the technical requirements. However, when the first-step aging temperature is increased to 735℃, the room temperature and high temperature tensile strength in both the XY and Z directions can meet the technical requirements.

[0115] Therefore, the additive manufacturing process proposed in this invention simplifies the traditional "homogenization treatment + solution heat treatment" into a one-step high-temperature heat treatment by optimizing the solution heat treatment regime. This ensures sufficient recrystallization while promoting the precipitation of grain boundary strengthening phases and effectively inhibiting excessive grain growth. By increasing the solution temperature and cooling rate, this process significantly improves the microstructure anisotropy of the additive-manufactured GH4169 alloy. Simultaneously, by adjusting the aging heat treatment process, the age-strengthening effect is enhanced, effectively compensating for the material softening phenomenon caused by high-temperature solution treatment. Ultimately, the above synergistic optimization strategy significantly improves the comprehensive mechanical properties of the additive-manufactured GH4169 alloy.

[0116] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An additive manufacturing method for GH4169 alloy, characterized in that, The additive manufacturing method includes at least the following sequential processes: alloy powder preparation, laser selective melting forming, solution heat treatment, and aging heat treatment. The solution heat treatment has a solution temperature ≥1080℃ and a cooling rate ≥400℃ / min; the aging heat treatment includes a first aging step and a second aging step performed sequentially, and the aging temperature of the first aging step is ≥735℃.

2. The additive manufacturing method for GH4169 alloy according to claim 1, characterized in that, The elemental composition of the alloy powder, by mass fraction, includes: Ni 50-55wt%, Cr 17-21wt%, Nb 4.75-5.50wt%, Mo 2.8-3.3wt%, Ti 0.65-1.15wt%, Al 0.2-0.8wt%, with the balance being Fe.

3. The additive manufacturing method for GH4169 alloy according to claim 2, characterized in that, The elemental composition of the alloy powder, by mass fraction, further includes: Co ≤ 1.00 wt%, Cu ≤ 0.30 wt%, C 0.035-0.055 wt%, Si ≤ 0.35 wt%, Mn ≤ 0.35 wt%, P ≤ 0.015 wt%, S ≤ 0.015 wt%, B ≤ 0.006 wt%, O ≤ 0.025 wt%, N ≤ 0.025 wt%, and Mg ≤ 0.01 wt%.

4. The additive manufacturing method for GH4169 alloy according to claim 1 or 2, characterized in that, The laser selective melting forming includes: after spreading powder, filling the forming environment with protective gas, and performing laser scanning using a strip scanning method; The thickness of the powder coating is 60-80 μm; And / or, the protective gas includes argon and / or helium, and the oxygen content in the forming environment is controlled to be ≤0.05%.

5. The additive manufacturing method for GH4169 alloy according to claim 4, characterized in that, The diameter of the laser scanning spot is 75-85 μm; And / or, the laser power of the laser scanning is 300-340W; And / or, the scanning speed of the laser scan is 1000-1100 mm / s; And / or, during the laser scanning process, the scanning directions of adjacent laser lines are opposite, and the scanning distance between adjacent laser lines is 0.09-0.11 mm.

6. The additive manufacturing method for GH4169 alloy according to claim 4, characterized in that, The width of the strip scanned band is 7-10 mm; And / or, the strip spacing of the strip scan is 0.05-0.08 mm; And / or, during the strip scanning process, the rotation angle of the strips between layers is 60°-70°.

7. The additive manufacturing method for GH4169 alloy according to claim 1 or 2, characterized in that, The solution heat treatment is carried out in a vacuum heat treatment furnace, and the vacuum degree inside the furnace is ≤1Pa; And / or, the solution temperature of the solution heat treatment is 1110-1120℃; And / or, the heat treatment holding time is 1-2 hours.

8. The additive manufacturing method for GH4169 alloy according to claim 1 or 2, characterized in that, The aging heat treatment is carried out in a vacuum heat treatment furnace, and the vacuum degree inside the furnace is ≤1Pa; And / or, the aging temperature of the first aging step is 735-750℃; And / or, the effective period of the first step is 6-8 hours; And / or, the aging temperature for the second step of aging is 620-635℃; And / or, the time limit for the second step is 4-6 hours; And / or, furnace cooling is performed between the first aging step and the second aging step, and the furnace cooling time is 1-3 hours; And / or, after the second step of aging is completed, argon gas is used for cooling.

9. A GH4169 alloy, characterized in that, The GH4169 alloy is prepared by the additive manufacturing method as described in any one of claims 1-8.

10. An application of the GH4169 alloy as described in claim 9, characterized in that, The GH4169 alloy is used to manufacture large and complex metal components.

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