Nickel-based superalloy material for laser additive emergency repair and preparation method and repair method thereof

Abstract

This invention relates to a nickel-based superalloy material for emergency repair of laser additive manufacturing, its preparation method, and its repair method, and pertains to the field of laser additive remanufacturing and emergency repair technology. The nickel-based superalloy material, by mass percentage, comprises the following components: C: 0.04–0.07%; Cr: 17.2–18.0%; Co: 7.0–7.9%; W: 1.10–1.60%; Mo: 4.6–5.3%; Al: 1.5–2.0%; Ti: 1.6–1.9%; Fe: 0.5–1.5%; Ta: 0.6–1.1%; Nb: 1.8–2.6%; B: 0.002–0.01%; Zr: 0.005–0.02%; with the balance being Ni; the sum of the mass percentages of all the above components is 100%. By adjusting the composition and proportions of the nickel-based superalloy, this invention allows for direct repair of components without heat treatment. After repair, the components can operate directly at high temperatures, significantly shortening the repair cycle for high-temperature components.

Description

Technical Field

[0001] This invention relates to the field of laser additive remanufacturing and emergency repair technology, and in particular to a nickel-based high-temperature alloy material for emergency repair of laser additive manufacturing, its preparation method, and its repair method. Background Technology

[0002] Nickel-based superalloys are a class of high-temperature materials with γ phase as the matrix. Among them, precipitation-strengthened nickel-based superalloys have γ′ phase as the main strengthening phase. However, while the high γ′ content improves the high-temperature strength of the alloy, it also leads to a sharp increase in the crack sensitivity of the material, making it prone to cracking under rapid melting and strong thermal cycling conditions, which poses a great challenge to the manufacturing and emergency repair of high-temperature components.

[0003] Laser additive manufacturing repair technology offers advantages such as concentrated heat input, high repair efficiency, and high material utilization, providing a new technical approach for the emergency repair of hot-end components of high-temperature alloys. However, existing nickel-based high-temperature alloys are still prone to cracking during laser additive manufacturing repair due to rapid cooling, large temperature gradients, and significant elemental segregation, resulting in insufficient stability in the repair process and limiting its engineering application in the field of emergency repair of high-temperature components. Summary of the Invention

[0004] The purpose of this invention is to provide a special nickel-based superalloy material for laser additive manufacturing used in the repair of nickel-based superalloy components, as well as its preparation and repair methods, in order to solve the problems of high crack sensitivity and long process cycle in emergency repair of nickel-based superalloys with high γ′ content.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a nickel-based high-temperature alloy material for emergency repair using laser additive manufacturing, comprising the following components (elements) by mass percentage:

[0007] C: 0.04–0.07%; Cr: 17.2–18.0%; Co: 7.0–7.9%; W: 1.10–1.60%; Mo: 4.6–5.3%; Al: 1.5–2.0%; Ti: 1.6–1.9%; Fe: 0.5–1.5%; Ta: 0.6–1.1%; Nb: 1.8–2.6%; B: 0.002–0.01%; Zr: 0.005–0.02%; balance Ni;

[0008] The sum of the mass percentages of the above components is 100%.

[0009] Furthermore, the nickel-based superalloy material comprises, by mass percentage, the following components (elements):

[0010] C: 0.053%; Cr: 17.67%; Co: 7.34%; W: 1.325%; Mo: 4.91%; Al: 1.76%; Ti: 1.81%; Fe: 1.07%; Ta: 0.88%; Nb: 2.14%; B: 0.0045%; Zr: 0.011%; balance Ni;

[0011] The sum of the mass percentages of the above components is 100%.

[0012] Furthermore, the nickel-based superalloy material is in powder form. Preferably, the particle size of the nickel-based superalloy powder is 53 μm to 106 μm.

[0013] This invention is applicable to the emergency repair of hot-end components with a tensile strength of less than 400 MPa at 900℃ in the deposited state. After laser additive repair using this nickel-based superalloy powder (i.e., powdered nickel-based superalloy material), the component can be used without heat treatment; during actual service, the working temperature of the repaired component can achieve the corresponding heat treatment effect.

[0014] Secondly, the present invention provides a method for preparing a nickel-based high-temperature alloy material for emergency repair using laser additive manufacturing, comprising the following steps:

[0015] According to the target composition ratio, the intermediate alloy containing the required components (elements) of the nickel-based superalloy material is formulated into an alloy mixture;

[0016] The alloy mixture is vacuum melted to obtain a liquid alloy.

[0017] The alloy liquid is atomized and solidified into alloy powder using a vacuum atomization process.

[0018] The alloy powder is sieved to obtain a powdered nickel-based high-temperature alloy material.

[0019] Further, the master alloy is selected from at least one of In738LC, In625, nickel-chromium, nickel-molybdenum, nickel-aluminum, nickel-niobium, cobalt-nickel-tungsten, and nickel-tantalum. Preferably, the master alloy includes In738LC, In625, nickel-chromium, nickel-molybdenum, nickel-aluminum, nickel-niobium, cobalt-nickel-tungsten, and nickel-tantalum.

[0020] Furthermore, the mass percentage of impurity elements in the alloy mixture is ≤0.03%.

[0021] Furthermore, the atomizing medium used in the vacuum atomization process is a high-purity inert gas. Preferably, the high-purity inert gas is argon with a purity of not less than 99.999%.

[0022] Furthermore, the sieving process involves passing the alloy powder through a 150-320 mesh sieve to collect powder with a particle size of 53μm-106μm.

[0023] Thirdly, the present invention also provides an application of the above-mentioned nickel-based superalloy material in laser additive manufacturing repair. Specifically, it provides an emergency repair method for laser additive manufacturing, which uses the aforementioned nickel-based superalloy material (powder) to repair a substrate. The method mainly includes the following steps: providing a substrate to be repaired; using powdered nickel-based superalloy material, depositing and repairing it on the surface of the substrate to be repaired through a laser additive manufacturing process.

[0024] Furthermore, the laser additive manufacturing emergency repair method includes the following steps:

[0025] S01. Substrate treatment:

[0026] Pre-treat (e.g., grind) and clean and dry the surface of the substrate of the metal component to be repaired;

[0027] S02. Parameter Settings:

[0028] The laser wavelength was set to 1064–1080 nm, the laser focal length to 200 mm, and the defocusing amount to 25 mm.

[0029] The laser power density was set at 390 W / mm², the scanning speed at 550 mm / min, and the overlap rate at 50%.

[0030] The powder feeding speed is set to 4.3 g / min;

[0031] The protective gas flow rate is set to 14 L / min and the powder feeding gas flow rate is set to 10 L / min. Both the protective gas and the powder feeding gas are high-purity inert gases.

[0032] S03. Laser Additive Repair:

[0033] The substrate to be repaired is fixed on a cooling fixture, and a laser beam is used to melt the synchronously conveyed powdered nickel-based high-temperature alloy material, which is then deposited layer by layer on the surface of the substrate to be repaired along a preset scanning trajectory to complete the additive repair.

[0034] Furthermore, the S01. substrate treatment step specifically includes:

[0035] Select the metal component to be repaired as the base material (the base material can be a γ′ phase strengthened nickel-based high-temperature alloy material, such as IN738LC), grind and remove rust (remove the oxide layer) on its surface, and then clean and dry it with an organic solvent (such as anhydrous ethanol).

[0036] Furthermore, S03. The laser additive repair steps specifically include:

[0037] Powdered nickel-based superalloy material is supplied to a powder feeding device (e.g., a powder feeder), and the substrate to be repaired is fixed on a cooling fixture (e.g., a water-cooled platform). The laser processing head and the substrate to be repaired are controlled to move relative to each other along a preset scanning trajectory. The laser beam is used to melt the synchronously fed powdered nickel-based superalloy material and deposit it layer by layer on the surface of the substrate to be repaired, thus completing the additive repair.

[0038] Furthermore, the high-purity inert gas is argon with a purity of not less than 99.999%. Preferably, the high-purity inert gas is argon with a purity of 99.999%.

[0039] Compared with the prior art, the present invention has the following advantages:

[0040] 1. By adjusting the composition and ratio of nickel-based high-temperature alloys, components can be repaired directly without heat treatment. After repair, the components can operate directly at high temperatures, significantly shortening the repair cycle of high-temperature components.

[0041] 2. This study solves the current problems of nickel-based superalloys exhibiting high strength but brittle fracture when used for emergency repair of turbine blades at high temperatures, as well as the issues of not brittle fracture at high temperatures but insufficient strength to meet stable operating conditions. This saves costs and provides basic data for the industrialization of nickel-based superalloys in the repair of high-temperature hot-end components. Attached Figure Description

[0042] Figure 1 The stress-strain diagram is obtained by directly performing a tensile test on the alloy of Example 1 of the present invention at room temperature.

[0043] Figure 2 The stress-strain curve of the alloy in Example 1 of this invention is obtained by directly conducting a high-temperature tensile test at 900 °C without high-temperature operation treatment (heat treatment).

[0044] Figure 3 The stress-strain diagram is obtained by performing a high-temperature tensile test at 900 °C on the alloy of Example 1 of the present invention after aging heat treatment at 900 °C for 10 h.

[0045] Figure 4 The stress-strain diagram is obtained from a high-temperature tensile test of alloy 1 at 900 °C.

[0046] Figure 5 The stress-strain diagram is obtained from a high-temperature tensile test of alloy 2 at 900 °C.

[0047] Figure 6 This is a metallographic microstructure of the alloy in Example 1 of the present invention at room temperature;

[0048] Figure 7 The image shows the metallographic microstructure of the alloy in Example 1 of this invention after aging heat treatment at 900 °C for 10 h.

[0049] Figure 8 This is a scanning electron microscope image (low magnification) of the tensile fracture surface of the alloy in Example 1 of the present invention at room temperature.

[0050] Figure 9 This is a scanning electron microscope image (high magnification) of the tensile fracture surface of the alloy in Example 1 of the present invention at room temperature.

[0051] Figure 10 The image shows a scanning electron microscope (low magnification) image of the tensile fracture surface of the alloy in Example 1 of this invention after aging at 900 °C for 10 h.

[0052] Figure 11 The image shows a scanning electron microscope (high magnification) image of the tensile fracture surface of the alloy in Example 1 of this invention after aging at 900 °C for 10 h.

[0053] Figure 12 This is a scanning electron microscope image showing the microstructure of the alloy in Example 1 of the present invention at room temperature.

[0054] Figure 13 This is a scanning electron microscope image showing the microstructure of the alloy in Example 1 of the present invention after aging at 900 °C for 10 h. Detailed Implementation

[0055] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention.

[0056] It should be noted that the nickel-based superalloy material described in this invention is not limited to powder form, but can also be in conventional forms such as ingots, wires, or plates. In this embodiment, powder is used as an example for illustration.

[0057] This invention provides a high-performance nickel-based high-temperature alloy powder for emergency repair using laser additive manufacturing. The elements and their mass percentages are as follows: C: 0.04–0.07%; Cr: 17.2–18.0%; Co: 7.0–7.9%; W: 1.10–1.60%; Mo: 4.6–5.3%; Al: 1.5–2.0%; Ti: 1.6–1.9%; Fe: 0.5–1.5%; Ta: 0.6–1.1%; Nb: 1.8–2.6%; B: 0.002–0.01%; Zr: 0.005–0.02%; the balance is Ni; the sum of the mass percentages of all the above elements is 100%.

[0058] Furthermore, the high-performance nickel-based high-temperature alloy powder for emergency repair using laser additive manufacturing contains the following elements and their mass percentages: C: 0.053%; Cr: 17.67%; Co: 7.34%; W: 1.325%; Mo: 4.91%; Al: 1.76%; Ti: 1.81%; Fe: 1.07%; Ta: 0.88%; Nb: 2.14%; B: 0.0045%; Zr: 0.011%; the balance is Ni; the sum of the mass percentages of all the above elements is 100%.

[0059] To prepare the above powder, the intermediate alloy containing the above elements can be vacuum melted in proportion, and then atomized into powder using vacuum atomization; then the powder is obtained by sieving.

[0060] This invention improves the forming stability of nickel-based superalloy powder in the laser additive repair process, reduces the risk of cracking during the repair process, and can be used for laser additive repair without subsequent heat treatment. It is suitable for emergency rapid repair of components such as high-temperature turbines.

[0061] Specifically, the steps for preparing the above-mentioned high-performance nickel-based high-temperature alloy powder for emergency repair using laser additive manufacturing are as follows:

[0062] S01. Prepare alloy mixture: Select intermediate alloys such as In738LC, In625, nickel-chromium, nickel-molybdenum, nickel-aluminum, nickel-niobium, cobalt-nickel-tungsten, and nickel-tantalum, and prepare alloy mixture according to the elements contained in the above powder and the mass percentage of each element.

[0063] In this step, the mass percentage of impurity elements is controlled to be ≤0.03% by limiting the purity of the selected intermediate alloy.

[0064] S02, Atomization Powder Making: The alloy mixture is melted into a qualified alloy liquid using a vacuum induction furnace. The alloy liquid is then injected into the intermediate tundish of the vacuum atomization powder making device. The alloy liquid flows out from the bottom hole of the intermediate tundish and is atomized into fine droplets when it comes into contact with high-purity argon gas as it passes through the atomization cladding nozzle of the vacuum atomization powder making device. The fine droplets are rapidly solidified into alloy powder in the atomization cylinder of the vacuum atomization device.

[0065] In this step, the high-purity argon gas is argon gas with a purity of not less than 99.999%.

[0066] S03. Sieving process: The obtained powder is sieved through a 150-320 mesh sieve to obtain a high-performance nickel-based high-temperature alloy powder for emergency repair of laser additive manufacturing with a particle size of 53μm-106μm.

[0067] On the other hand, the steps for laser additive manufacturing (such as repair) using the aforementioned nickel-based superalloy powder are as follows:

[0068] S01. Selection and treatment of substrate: Select the metal component to be repaired as the substrate, such as γ′ phase reinforced nickel-based high-temperature alloy material as the substrate; grind the surface of the substrate with a grinding machine to remove the surface oxide layer, clean it with anhydrous ethanol, and dry it in a drying oven for later use.

[0069] In this step, the substrate material is IN738LC.

[0070] S02. Laser Additive Manufacturing Technology Repair Platform Parameter Settings: Place the substrate on the water-cooled platform and determine the laser scanning path according to the shape to be repaired. Add high-performance nickel-based high-temperature alloy powder for emergency repair in laser additive manufacturing to the laser powder feeder, fusing the alloy powder onto the substrate until the required repair thickness is achieved. Set the laser wavelength to 1064–1080 mm, the laser focal length to 200 mm, the defocusing amount to 25 mm, and the laser power density to 390 W / mm². 2 The powder feeding rate was 4.3 g / min, the scanning speed was 550 mm / min, the central protective gas flow rate was 14 L / min, the powder feeding gas flow rate was 10 L / min, and the overlap rate was 50%. Both the protective gas and the powder feeding gas were argon with a purity of 99.999%.

[0071] In this step, the laser additive manufacturing equipment includes a laser, a cladding nozzle, and a CNC work platform.

[0072] S03, Laser Additive Repair: Add high-performance nickel-based high-temperature alloy powder for emergency repair in laser additive manufacturing to the laser cladding machine. Use the coaxial synchronous powder feeding method (or coaxial lateral powder feeding method) to add the high-performance nickel-based high-temperature alloy powder to the substrate surface along the laser scanning trajectory to complete the additive repair.

[0073] The advantages of this invention compared to existing technologies are as follows: By adjusting the composition and ratio of the nickel-based superalloy, components can be repaired directly without heat treatment. After repair, the components can operate directly at high temperatures, significantly reducing the repair cycle for high-temperature components. This solves the current problems of nickel-based superalloys used in emergency turbine blade repair exhibiting high strength but brittle fracture at high temperatures, and the issue of not fracturing at high temperatures but not achieving stable operating strength. It saves costs and provides fundamental data for the industrialization of nickel-based superalloys in the repair of high-temperature hot-end components.

[0074] Samples manufactured using laser additive manufacturing technology from powder prepared by the aforementioned nickel-based superalloy preparation method exhibit a yield strength of 640-680 MPa, a tensile strength of 940-980 MPa, and an elongation of approximately 33% at room temperature, without significant cracking. When subjected to tensile testing at 900℃ without heat treatment, the yield strength reaches 440-470 MPa, the tensile strength 490-520 MPa, and the elongation remains at approximately 5.8%. After aging at 900℃ for 10 hours, the yield strength reaches 380-400 MPa, the tensile strength 430-450 MPa, and the elongation is approximately 12%, meeting the mechanical performance requirements for high-temperature hot-end components under prolonged high-temperature service conditions after repair. This demonstrates broad application prospects in the field of high-temperature component repair.

[0075] Compared with existing high-strength nickel-based superalloys, this invention optimizes the alloy element ratio to reduce the cracking risk during laser additive manufacturing while ensuring high-temperature strength. Specifically, it appropriately reduces the Ti and Al content to weaken the crack sensitivity caused by excessive γ′ phase precipitation, while reducing the W and Ta content to decrease the formation of high-temperature brittle phases; it appropriately increases the Co and Mo content to improve alloy strength through solid solution strengthening; and trace amounts of B strengthen grain boundaries, thereby improving the material's crack resistance and microstructure stability under high-temperature conditions.

[0076] The following specific examples will provide further explanation.

[0077] Example 1

[0078] The high-performance nickel-based high-temperature alloy powder for emergency repair of laser additive manufacturing contains the following elements and their mass percentages:

[0079] C: 0.053%; Cr: 17.67%; Co: 7.34%; W: 1.325%; Mo: 4.91%; Al: 1.76%; Ti: 1.81%; Fe: 1.07%; Ta: 0.88%; Nb: 2.14%; B: 0.0045%; Zr: 0.011%; balance Ni; the sum of the mass percentages of all elements is 100%.

[0080] The roles of some elements in the above-mentioned high-performance nickel-based superalloy powder are explained below:

[0081] C: A small amount of C is beneficial for the formation of stable MC-type carbides, which can strengthen grain boundaries, inhibit grain boundary slip, and improve the high-temperature creep performance of alloys; however, excessive C content can easily form a continuous carbide network at grain boundaries, reducing material plasticity and increasing the risk of cracking.

[0082] Cr: Cr is the main antioxidant and corrosion resistant element. It can form a dense oxide film at high temperatures, which can improve the oxidation resistance and thermal stability of the alloy. At the same time, it has a certain solid solution strengthening effect on the matrix.

[0083] Al: Al is an important forming element of the γ′ strengthening phase. Appropriate addition is beneficial to the dispersed precipitation of the γ′ phase and improves the high-temperature strength of the alloy. However, excessive content will increase the crack sensitivity in the laser additive manufacturing process.

[0084] Ti: Ti is also a γ′ phase forming element, which can improve precipitation strengthening effect and enhance the high-temperature strength of alloys. Excessive addition will increase compositional segregation and increase the risk of cracking.

[0085] Ta: Ta is a refractory strengthening element that can improve the high-temperature load-bearing capacity and creep resistance of alloys, but excessive content can promote the formation of brittle phases and increase the risk of cracking.

[0086] Nb: Nb is a solid solution strengthening element and can also participate in carbide formation. Adding a small amount can improve grain boundary stability and increase high-temperature strength.

[0087] Mo: Mo is an important solid solution strengthening element that can improve the strengthening of the matrix and enhance high-temperature strength and creep resistance.

[0088] W: W is a refractory strengthening element that can improve the high-temperature strength and structural stability of alloys, but excessive content will increase the alloy's susceptibility to cracking.

[0089] Zr: Zr is a trace grain boundary strengthening element that can improve grain boundary bonding strength, enhance high-temperature creep resistance, and improve crack resistance. However, excessive addition can cause cracking during additive manufacturing.

[0090] B: B is a typical grain boundary strengthening element. Adding trace amounts can improve grain boundary strength and high-temperature performance.

[0091] The following steps are used to prepare high-performance nickel-based high-temperature alloy powder for emergency repair using laser additive manufacturing:

[0092] S01. Prepare the alloy mixture: Select In738LC, In625, nickel-chromium, nickel-molybdenum, nickel-aluminum, nickel-niobium, cobalt-nickel-tungsten, and nickel-tantalum master alloys according to the chemical composition ratio required by this invention, weigh and mix them to obtain an alloy mixture whose composition meets the design requirements.

[0093] In this step, the mass percentage of impurity elements is controlled to be ≤0.03% by limiting the purity of the selected intermediate alloy.

[0094] S02. Atomization Powdering: The above alloy mixture is added to a vacuum induction furnace and heated and melted under vacuum or inert atmosphere conditions until completely melted and thoroughly stirred to obtain a homogeneous alloy liquid. The alloy liquid is transferred to the tundish of a vacuum atomization powdering device, flowing out through the bottom drain of the tundish, and coming into contact with high-purity argon gas at the atomization cladding nozzle, where it is atomized into fine droplets by a high-speed gas flow. The purity of the high-purity argon gas is 99.999%. The fine droplets rapidly cool and solidify within the atomization cylinder of the vacuum atomization device, forming spherical or near-spherical alloy powder.

[0095] S03. Powder sieving: The obtained alloy powder is sieved through a 150-320 mesh sieve to obtain high-performance nickel-based high-temperature alloy powder for emergency repair in laser additive manufacturing with a particle size of 53μm-106μm. If necessary, low-temperature drying can be performed under vacuum or inert atmosphere to reduce the moisture and oxygen content adsorbed on the powder surface.

[0096] Based on the aforementioned high-performance nickel-based high-temperature alloy powder specifically designed for emergency laser additive repair, laser additive manufacturing is carried out according to the following method, with the following steps:

[0097] S01. Selection and treatment of the substrate: An alloy material capable of forming a good metallurgical bond with the alloy repair layer of the present invention is selected as the substrate, such as a typical nickel-based high-temperature alloy or a compatible heat-resistant steel material; in this embodiment, IN738LC is selected. The surface of the substrate is machined (polished) using a grinding machine to remove the oxide layer. The surface of the substrate is cleaned with anhydrous ethanol. After cleaning, the substrate is placed in a drying oven to dry for later use.

[0098] S02. Setting up the laser additive manufacturing equipment and process parameters: The aforementioned high-performance nickel-based high-temperature alloy powder for emergency laser additive repair is added to the powder feeder for laser additive repair. The substrate is fixed on a water-cooled platform, and the laser scanning path and interlayer overlap method are set in the CNC system according to the geometry of the defect to be repaired. The main process parameters are set as follows: Laser wavelength: 1064–1080 nm; Laser focal length: 200 mm; Defocusing amount: 25 mm; Laser power density: 390 W / mm²; Powder feeding speed: 4.3 g / min; Scanning speed: 550 mm / min; Overlap rate: 50%; Central protective gas flow rate: 14 L / min; Powder feeding gas flow rate: 10 L / min; Both the protective gas and the powder feeding gas are argon with a purity of 99.999%.

[0099] S03. Laser Cladding: Under the above process parameters, the high-performance nickel-based high-temperature alloy powder for emergency repair using laser additive manufacturing is clad layer by layer onto the substrate surface through a multi-pass, multi-layer scanning method until the required repair thickness is achieved, resulting in a repair layer with good metallurgical bonding to the substrate and a dense internal structure. The entire repair process achieves good mechanical properties without subsequent heat treatment.

[0100] In addition, to verify the superiority of the material of the present invention, two comparative examples were selected as comparative references for Example 1.

[0101] Comparative Example 1: An existing nickel-based superalloy composition was selected as the comparative material, and its main element mass percentages are as follows: Cr: 19.0%; Co: 4.34%; W: 1.325%; Mo: 5.46%; Al: 1.76%; Ti: 1.82%; Fe: 1.21%; Ta: 0.88%; Nb: 2.30%; B: 0.0032%; balance Ni.

[0102] Comparative Example 2: Another nickel-based superalloy composition was selected as the comparative material, with the following main element mass percentages: Cr: 17.25%; Co: 8.03%; W: 1.84%; Mo: 3.79%; Al: 2.85%; Ti: 2.47%; Fe: 0.71%; Ta: 1.22%; Nb: 1.68%; B: 0.0043%; balance Ni.

[0103] Comparative Examples 1 and 2 were prepared using the same laser additive repair process as in Example 1, and tensile tests were conducted at 900 °C. During the tests, it was found that the samples of Comparative Examples 1 and 2 exhibited premature fracture and insufficient plastic deformation capacity during laser additive repair and subsequent high-temperature tensile testing. This indicates that the alloy composition has poor forming stability under the repair conditions described, making it difficult to meet the requirements for emergency repair.

[0104] The tensile properties and microstructure are analyzed below.

[0105] To verify the comprehensive performance of the nickel-based high-temperature alloy powder and its repair process of the present invention, tensile specimens were prepared using the alloy powder and process parameters prepared in Example 1, and mechanical property tests and microstructure and fracture characterization were carried out at room temperature and 900℃.

[0106] Tensile properties:

[0107] The high-performance nickel-based high-temperature alloy powder for emergency repair using laser additive manufacturing in Example 1, and the high-temperature nickel-based alloy powders in Comparative Examples 1 and 2, were used to prepare deposited samples using the same laser additive manufacturing process. Subsequently, material containing only the laser additive layer was cut from each sample by wire cutting and processed into general tensile test specimens (standard tensile specimens).

[0108] For the deposited specimens of Example 1, room temperature tensile tests and high temperature tensile tests were performed directly at 900 °C without heat treatment. The specimens after aging at 900 °C for 10 hours were subjected to high temperature tensile tests at 900 °C to evaluate the mechanical behavior of the repaired specimens under different service conditions.

[0109] The deposited samples of Comparative Example 1 and Comparative Example 2 were subjected to high-temperature tensile tests at 900 °C without heat treatment to evaluate the suitability of the existing alloy composition under laser additive repair conditions.

[0110] like Figure 1 As shown, the stress-strain curves of the alloy molded parts of the present invention in the room temperature tensile test indicate that the material has obvious yield stage and uniform plastic deformation stage, with a room temperature yield strength of 640-680 MPa, a tensile strength of 940-980 MPa, and an elongation of about 33%.

[0111] like Figure 2 As shown, when the alloy of the present invention is subjected to a tensile test at 900 °C, the overall stress-strain curve level is reduced, but the plastic deformation process is still smooth, with a yield strength of 440-470 MPa, a tensile strength of 490-520 MPa, and an elongation of about 5.8%.

[0112] like Figure 3 As shown, after aging the samples at 900 ℃ for 10 h, a high-temperature tensile test at 900 ℃ was conducted. The results showed that the yield strength could still reach 380–400 MPa, the tensile strength was 430–450 MPa, and the elongation was approximately 12%. Figures 1-3 It is evident that the alloy of this invention exhibits high strength and certain plasticity under both room temperature and long-term service conditions at 900 ℃, thus meeting the service requirements after component repair.

[0113] like Figure 4 As shown, when the alloy of Comparative Example 1 was directly subjected to a high-temperature tensile test at 900 °C, the overall load-bearing capacity of its stress-strain curve was significantly lower than that of the alloy of Example 1 of this invention, with a tensile strength of approximately 398 MPa. At the same time, the plastic deformation stage of the curve was shorter and the fracture strain was lower, indicating that the high-temperature load-bearing capacity and plastic stability of this composition system under laser additive repair conditions were relatively insufficient.

[0114] like Figure 5 As shown, the stress-strain curve of alloy 2 under high temperature tensile test at 900 °C shows that its tensile strength is about 431 MPa, which is slightly higher than that of alloy 1, but still lower than that of alloy 1 in this invention. It also shows a lower plastic deformation capacity during the tensile process, and the overall mechanical property stability of the material under high temperature service conditions decreases.

[0115] Metallographic microstructure observation:

[0116] Metallographic preparation and optical microscopy observation were performed on samples at room temperature and after aging at 900 °C for 10 h.

[0117] like Figure 6 As shown, the metallographic microstructure of the alloy of the present invention at room temperature is uniform and dense, with clear grain outlines. No through cracks or obvious shrinkage pores are observed in the microstructure, indicating that there are no serious defects in the laser additive manufacturing process.

[0118] like Figure 7 As shown, the metallographic microstructure of the alloy of the present invention remains continuous and dense after aging treatment at 900 °C for 10 h, with basically intact grain boundary morphology. No macroscopic grain boundary cracking was observed, indicating that the alloy has good microstructure stability under high temperature and long-term operation conditions.

[0119] Fracture morphology:

[0120] The tensile fracture surfaces at room temperature and after aging at 900 °C for 10 h were observed by scanning electron microscopy.

[0121] like Figure 8 , 9 As shown, the fracture surface of the alloy of the present invention after being stretched at room temperature is illustrated by a scanning electron microscope. Figure 8 The low magnification morphology shows that the fracture surface is generally rough and undulating, with visible holes and tearing areas in some areas; Figure 9 The high-magnification morphology reveals numerous pitted features, with obvious traces of plastic deformation on the pit walls.

[0122] like Figure 10 , 11 As shown, the tensile fracture surface of the alloy of the present invention after aging treatment at 900 °C for 10 h generally exhibits a relatively flat blocky step morphology. Figure 10 The low-magnification fracture morphology shows that the fracture mode is mainly block fracture, and no obvious large-sized dimple features are observed. Figure 11 The high-magnification fracture morphology shows that the fracture surface is relatively dense and the traces of plastic deformation are relatively weak, indicating that the plasticity of the sample has decreased under long-term high-temperature environment, but it still maintains a certain load-bearing capacity.

[0123] Microscopic tissue SEM details:

[0124] Scanning electron microscopy was used to observe the microstructures under conditions of room temperature and aging at 900 °C for 10 h.

[0125] like Figure 12 As shown in the detailed scanning electron microscope images of the microstructure of the alloy of the present invention at room temperature, the grain boundaries are continuous, and fine second-phase particles are uniformly distributed inside the grains and near the grain boundaries. The particles are small in size and uniformly distributed, and no obvious large-sized brittle phase aggregation is observed.

[0126] like Figure 13 As shown in the scanning electron microscope image of the microstructure of the alloy of the present invention after aging at 900 °C for 10 h, the grain boundaries remain continuous, the second phase particles are basically uniformly distributed in the grain and grain boundary regions, no continuous network brittle phase is formed, and the overall microstructure is stable.

[0127] In summary, by optimizing the content of elements such as Ti, Al, W, and Ta in nickel-based superalloys and employing gas atomization powder preparation and laser additive repair, the emergency repair-specific nickel-based superalloy material obtained by this invention can achieve excellent room temperature and high temperature mechanical properties without heat treatment, and maintains stable microstructure and fracture toughness under long-term operation at 900 ℃, making it suitable for rapid emergency repair.

[0128] The embodiments described above are merely preferred embodiments of the present invention and are not exhaustive examples of all possible implementations of the present invention. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. Nickel-based superalloy material for laser additive emergency repair, characterized in that, By weight percentage, it includes the following components: C: 0.04~0.07%; Cr: 17.2~18.0%; Co: 7.0~7.9%; W: 1.10~1.60%; Mo: 4.6~5.3%; Al: 1.5~2.0%; Ti: 1.6–1.9%; Fe: 0.5–1.5%; Ta: 0.6~1.1%; Nb: 1.8~2.6%; B：0.002～0.01%； Zr: 0.005–0.02%; balance Ni; The sum of the mass percentages of the above components is 100%.

2. The nickel-base superalloy material of claim 1, wherein, By weight percentage, it includes the following components: C: 0.053%; Cr: 17.67%; Co: 7.34%; W: 1.325%; Mo: 4.91%; Al: 1.76%; Ti: 1.81%; Fe: 1.07%; Ta: 0.88%; Nb: 2.14%; B: 0.0045%; Zr: 0.011%; balance Ni; The sum of the mass percentages of the above components is 100%.

3. The nickel-based superalloy material according to claim 1 or 2, characterized in that, The nickel-based superalloy material is in powder form.

4. A method of producing a nickel-based superalloy material as claimed in claim 3, characterized in that Includes the following steps: According to the target composition ratio, the intermediate alloy containing the required components of the nickel-based superalloy material is formulated into an alloy mixture; The alloy mixture is vacuum melted to obtain a liquid alloy. The alloy liquid is atomized and solidified into alloy powder using a vacuum atomization process. The alloy powder is sieved to obtain a powdered nickel-based high-temperature alloy material.

5. The preparation method according to claim 4, characterized in that, The intermediate alloy is selected from at least one of In738LC, In625, nickel-chromium, nickel-molybdenum, nickel-aluminum, nickel-niobium, cobalt-nickel-tungsten, and nickel-tantalum; The mass percentage of impurity elements in the alloy mixture is ≤0.03%.

6. The preparation method according to claim 4, characterized in that, The atomizing medium used in the vacuum atomization process is a high-purity inert gas.

7. The preparation method according to claim 6, characterized in that, The high-purity inert gas is argon with a purity of not less than 99.999%.

8. The preparation method according to claim 4, characterized in that, The sieving process involves passing the alloy powder through a 150-320 mesh sieve to collect powder with a particle size of 53μm-106μm.

9. A method of laser additive manufacturing emergency repair, characterized in that, Includes the following steps: Provide the substrate to be repaired; Using the nickel-based high-temperature alloy material as described in claim 3, laser additive manufacturing process is used to deposit and repair the substrate surface.

10. The laser additive manufacturing emergency repair method of claim 9, wherein, Includes the following steps: S01. Substrate treatment: The surface of the substrate of the metal component to be repaired is pretreated, cleaned, and dried. S02. Parameter Settings: The laser wavelength was set to 1064–1080 nm, the laser focal length to 200 mm, and the defocusing amount to 25 mm. The laser power density was set at 390 W / mm², the scanning speed at 550 mm / min, and the overlap rate at 50%. The powder feeding speed is set to 4.3 g / min; The flow rate of the shielding gas is 14 L / min, and the flow rate of the powder feeding gas is 10 L / min, and the shielding gas and the powder feeding gas are both high-purity inert gases; S03. Laser additive repair: The substrate to be repaired is fixed on a cooling tool, the powder nickel-based superalloy material is synchronously conveyed, the laser beam is used to melt the powder nickel-based superalloy material, and the powder nickel-based superalloy material is deposited on the surface of the substrate to be repaired layer by layer along a preset scanning track, so that the additive repair is completed.

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