A manufacturing method of an electron beam selective area 3D printing Ni-based single crystal superalloy hollow blade

Abstract

The application provides a manufacturing method of an electron beam selective area 3D printed Ni-based single crystal high-temperature alloy hollow blade, which comprises the following steps: putting alloy raw materials into a water-cooled copper crucible induction melting furnace for melting, obtaining a Ni-based alloy rod B2 through casting and machining, using a plasma rotating electrode method to prepare spherical Ni-based alloy powder F1, obtaining spherical Ni-based alloy powder F2 after cleaning and screening, and loading the powder into an electron beam 3D printer; performing additive design on a hollow blade model, setting parameters of the printer, and performing electron beam selective area 3D printing; after the printing is completed, recycling the powder to obtain a Ni-based alloy hollow blade rough piece Z1, performing solid solution and aging treatment to obtain a Ni-based alloy hollow blade rough piece Z2, performing machining to obtain a Ni-based alloy hollow blade Z3, and performing plasma polishing treatment to obtain a Ni-based single crystal hollow blade. The application can be used for preparing high-temperature alloy parts with complex structures and large sizes, and has the advantages of high efficiency, good uniformity of structure, high cleanliness and high yield.

Description

Technical Field

[0001] This invention relates to the field of metal additive manufacturing technology, and more particularly to a method for manufacturing Ni-based single-crystal high-temperature alloy hollow blades using electron beam selective 3D printing. Background Technology

[0002] In modern advanced turbine engines, more than 50% of the materials used are high-temperature alloys, of which Ni-based single-crystal alloys account for about 40%. Ni-based single-crystal alloys have excellent comprehensive performance at medium and high temperatures and are mainly used in structural components that operate at 850℃~1150℃ in the aerospace field, such as working blades, turbine disks, and combustion chambers of aero engines. At present, Ni-based single-crystal blades are mainly prepared by investment casting, but the casting method has some disadvantages, such as: (1) the water-cooled copper crucible vacuum induction melting equipment is complicated to operate and expensive; (2) the casting yield is low, and problems such as impurities or large-angle skewed crystals and shrinkage porosity are easy to occur during the casting process; (3) the casting cycle is long and the flexibility is poor. In addition, Ni-based single-crystal high-temperature alloys are expensive. These factors have resulted in a high price for Ni-based single-crystal blades, which restricts the application of Ni-based single-crystal materials in aerospace vehicles and gas turbines. Summary of the Invention

[0003] Traditional casting methods for preparing Ni-based single-crystal hollow blades suffer from low yield (approximately 10%) and poor performance due to impurities, large-angle skewed crystals, and shrinkage porosity. This invention provides a method for manufacturing Ni-based single-crystal high-temperature alloy hollow blades using selective electron beam 3D printing. The invention primarily utilizes full-process control, employing high-purity metal components for melting to obtain high-purity Ni-based alloy rods. Ni-based alloy powder is then prepared using a rotating electrode method, followed by vacuum plasma cleaning to further remove impurities. After sieving, high-purity Ni-based alloy powder for selective electron beam 3D printing is obtained. Subsequently, in the vacuum environment of the electron beam 3D printing equipment's forming chamber, Ni-based alloy hollow blade blanks are prepared using a selector method. Following solution treatment and aging, machining, and plasma polishing, Ni-based single-crystal hollow blades meeting design requirements are finally obtained. This method can prepare high-temperature alloy parts with complex structures and large dimensions, offering advantages such as high efficiency, good microstructure uniformity, high cleanliness, and high yield. The yield of Ni-based single-crystal hollow blades (over 90%) is significantly improved compared to traditional casting methods (approximately 10%). This method is highly suitable for manufacturing high-value, structurally complex parts such as Ni-based single-crystal hollow blades, and features high efficiency, high yield, and excellent performance.

[0004] The technical means employed in this invention are as follows:

[0005] A method for manufacturing Ni-based single-crystal superalloy hollow blades using selective electron beam 3D printing includes the following steps:

[0006] Step 1: The proportioned alloy raw materials are placed in a water-cooled copper crucible induction melting furnace for melting, and Ni-based alloy rod B2 is obtained by casting and machining.

[0007] Step 2: Prepare spherical Ni-based alloy powder F1 from Ni-based alloy rod B2 using the plasma rotating electrode method;

[0008] Step 3: Clean and sieve the spherical Ni-based alloy powder F1 to obtain spherical Ni-based alloy powder F2, and load the spherical Ni-based alloy powder F2 into the powder storage box of the electron beam 3D printer.

[0009] Step 4: Perform additive design on the hollow blade model, set printer parameters, and perform electron beam selective 3D printing;

[0010] Step 5: After electron beam selective 3D printing is completed, the powder is recycled to obtain Ni-based alloy hollow blade blank Z1;

[0011] Step 6: Perform solution treatment and aging treatment on the Ni-based alloy hollow blade blank Z1 to obtain the Ni-based alloy hollow blade blank Z2;

[0012] Step 7: Machining the Ni-based alloy hollow blade blank Z2 to obtain the Ni-based alloy hollow blade Z3;

[0013] Step 8: Perform plasma polishing on the Ni-based alloy hollow blade Z3 to obtain a Ni-based single-crystal hollow blade.

[0014] Furthermore, in step one, the alloy raw materials are all pure metal raw materials with a purity of 99.999%, containing the following components in parts by weight: Cr: 2.0-4.6%; Co: 0.2-16.5%; Mo: 1.0-3.9%; W: 5.0-6.0%; Ta: 5.0-8.25%; Al: 5.5-6.0%; Re: 4.0-6.9%; Ru: 2.0-6.0%; Hf: 0.1%; and the remainder is Ni.

[0015] Furthermore, in step one, when the vacuum degree is less than 10... -3 The master alloy is smelted in a water-cooled copper crucible induction levitation melting furnace at a temperature of 1550-1750℃ for 5-15 minutes. The alloy composition is homogenized by 1-5 meltings. A Ni-based alloy rod B1 is cast into a melting mold shell made of CaO. The size of Ni-based alloy rod B1 is 71×290mm. After machining, Ni-based alloy rod B2 with a size of 70×285mm and a surface roughness Ra<0.8μm is produced.

[0016] Furthermore, in step two, the plasma rotating electrode method uses a plasma rotating electrode powder preparation device. The Ni-based alloy rod B2 is loaded into the plasma rotating electrode powder preparation device, the electrode rotation speed is set to 16000-25000 r / min, the plasma arc current is 1500-2600 A, and the Ni-based alloy powder is prepared under vacuum. After preparation, spherical Ni-based alloy powder F1 with a particle size distribution of 50-175 μm is obtained by sieving.

[0017] Further, in step three, Ni-based alloy powder F1 is loaded into a vacuum plasma cleaning device, using a mixed gas medium of H2:Ar2 = 1:1, with a power setting of 210-270W and a time of 1-10 minutes for argon ion cleaning; after cleaning, Ni-based alloy powder F1 is sieved to obtain spherical Ni-based alloy powder F2 with a particle size distribution of 45-155μm.

[0018] Further, in step four, the additive design method is as follows: A machining allowance of 0.5–1.5 mm is added to the outside of the hollow blade 3D model M1 to form a 3D printed hollow blade blank part model M2. A spiral crystal selector structure 3D model X1 is designed at the bottom center of the 3D printed hollow blade blank part model M2, and combined to form a 3D printed hollow blade model Y1. The spiral crystal selector has a pitch of 20–35 mm, a diameter of 10–30 mm, a wire diameter of 4–6 mm, a helix angle of 35–70°, and 1–3 spiral turns, so that the obtained single crystal main orientation is in the

[001] direction. The 3D printed hollow blade model Y1 is sliced, with a slice layer thickness of 0.03–0.3 mm, to obtain 3D printed hollow blade data parameters Y2, and the 3D printed hollow blade data parameters Y2 are imported into an electron beam 3D printer.

[0019] The printer parameter settings include: vacuuming to ≤0.3Pa, preheating temperature setting to 1000~1300℃, and holding time to 30min; the part solid printing parameters are set as follows: electron beam current to 25~48mA, and scanning speed to 5-15m / s; after printing, the vacuum is allowed to cool naturally to room temperature with the furnace.

[0020] Furthermore, in step five, when the powder is in a pseudo-sintered state and forms sintered bricks under the action of preheating and sintering at high temperature for a long time, the part is in the sintered bricks. The sintered bricks are transported to the electron beam powder recovery equipment, and 1kg of Ni-based alloy powder F2 is pre-placed in the powder recovery equipment. After the equipment door is sealed, the spraying is started. Ni-based alloy powder F2 is sprayed out from the spray gun under high pressure, spraying the sintered bricks and gradually breaking up the bricks to form recovered Ni-based alloy powder F3. After the spraying is completed, the Ni-based alloy hollow blade blank Z1 is taken out.

[0021] Furthermore, in step six, the Ni-based alloy hollow blade blank Z1 is placed in a high-vacuum heat treatment furnace for solution treatment and aging treatment, specifically including the following steps:

[0022] The pressure inside the high-vacuum heat treatment furnace was reduced to 10. -3 Pa, heat treatment: starting from room temperature of 20℃, heat up to 1000℃ at a heating rate of 10℃ / min, then heat up to 1300±5℃ at a heating rate of 5℃ / min, then heat up to 1350±5℃ at a heating rate of 2.5℃ / min, and hold at 1350±5℃ for 10h~20h.

[0023] After the heat preservation period, 99.999% high-purity argon gas is slowly introduced into the furnace, and the furnace blower is started. Argon gas is introduced until the furnace pressure reaches 90 kPa, at which point the argon gas introduction is stopped. Cooling is then started at a cooling rate of 2.5℃ / s to 50℃. After that, starting from the furnace temperature of 50℃, the temperature is increased to 870-920℃ at a heating rate of 10℃ / min, and held for 12-30 hours. After the heat preservation period, 99.999% high-purity argon gas is slowly introduced into the furnace, and the furnace blower is started. Argon gas introduction is stopped until the furnace pressure reaches 90 kPa, at which point the argon gas introduction is stopped. Cooling is then started at a cooling rate of 2.5℃ / s to 50℃. The furnace door is then opened, and the Ni-based alloy hollow blade blank Z2, which has undergone solution treatment and aging treatment, is removed.

[0024] Furthermore, in step seven, the cutting speed of the machining is 400-1600 r / min, the feed rate is 200-1200 mm / min, and the cutting width is 4-10 mm, in order to remove the surface machining allowance.

[0025] Furthermore, in step eight, the polishing temperature of the plasma polishing treatment is 75℃, the polishing voltage is 250-350V, the polishing time is 2-10min, and the plasma polishing treatment is performed using a plasma liquid composed of ammonium sulfate, sodium citrate, and distilled water, with the ratio of ammonium sulfate:sodium citrate:distilled water being (1-5):(0.5-2.5):100; the surface roughness Ra of the Ni-based single crystal hollow blade Z4 is <0.8μm.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. This invention utilizes a fully controlled process, employing high-purity metal components for smelting to obtain high-purity Ni-based alloy rods. Ni-based alloy powder is then prepared using a rotating electrode method, followed by vacuum plasma cleaning to further remove impurities. After sieving, high-purity Ni-based alloy powder is obtained. Subsequently, in the vacuum forming chamber of an electron beam 3D printing machine, Ni-based alloy hollow blade blanks are prepared using a crystal selector method. Following solution treatment and aging, machining, and plasma polishing, satisfactory Ni-based single-crystal hollow blades are obtained. This method is highly suitable for the high-performance manufacturing of Ni-based single-crystal hollow blades, featuring high efficiency and high yield, and holds broad promise for the manufacture of high-temperature, high-performance blades in the aerospace and gas turbine fields.

[0028] 2. The method of this invention can prepare high-temperature alloy parts with complex structures and large dimensions, and has the advantages of high efficiency, good microstructure uniformity, high cleanliness and high yield. The yield of Ni-based single crystal hollow blades (over 90%) is significantly improved compared with traditional casting methods (about 10%).

[0029] Based on the above reasons, this invention can be widely applied in fields such as metal additive manufacturing. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0035] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0036] Example 1

[0037] This invention provides a method for manufacturing Ni-based single-crystal superalloy hollow blades using selective electron beam 3D printing. It discloses a complete manufacturing process for Ni-based alloy powder and selective electron beam 3D printing to prepare Ni-based single-crystal superalloy hollow blades. This invention provides an additive manufacturing method for preparing Ni-based single-crystal superalloy hollow blades that is superior to traditional casting methods. It is a complete manufacturing process that utilizes high-purity Ni-based superalloy powder and prepares Ni-based single-crystal superalloy hollow blades using selective electron beam 3D printing equipment, resulting in a significantly improved yield (over 90%) and high-temperature performance.

[0038] The present invention discloses a method for manufacturing Ni-based single-crystal superalloy hollow blades using selective electron beam 3D printing, comprising the following steps:

[0039] (1) Select pure metal raw materials with a purity of 99.999% and formulate them according to the alloy composition. The chemical composition of the alloy is calculated by weight percentage as follows: Cr: 2.0-4.6%; Co: 0.2-16.5%; Mo: 1.0-3.9%; W: 5.0-6.0%; Ta: 5.0-8.25%; Al: 5.5-6.0%; Re: 4.0-6.9%; Ru: 2.0-6.0%; Hf: 0.1%; and the remainder is Ni.

[0040] (2) When the vacuum degree is less than 10 -3 The master alloy is smelted in a water-cooled copper crucible induction levitation furnace at a temperature of 1550-1750℃ for 5-15 minutes. The alloy composition is homogenized by 1-5 smelting cycles. A melting mold shell made of CaO is then used to cast Ni-based alloy rods B1. The obtained Ni-based alloy rod B1 has a size of 71×290mm. After machining, it is made into Ni-based alloy rod B2 with a size of 70×285mm and a surface roughness Ra<0.8μm.

[0041] (3) Load the Ni-based alloy rod B2 into the plasma rotating electrode powder making equipment, and carry out Ni-based alloy powder preparation under vacuum. The electrode rotation speed is 16000-25000 r / min, the plasma arc current is 1500-2600 A, and spherical Ni-based alloy powder F1 with a particle size distribution of 50-175 μm is obtained by sieving.

[0042] (4) The obtained Ni-based alloy powder F1 is loaded into a vacuum plasma cleaning equipment for argon ion cleaning. A mixed gas medium of H2:Ar2 = 1:1 is selected, the power is 210-270W, and the time is 1-10 minutes. After the treatment, the powder is sieved to obtain spherical Ni-based alloy powder F2 with a diameter of 45-155μm, which is used for electron beam selective melting 3D printing.

[0043] (5) Load a sufficient amount of Ni-based alloy powder F2 into the powder storage box of the electron beam 3D printer;

[0044] (6) The hollow blade 3D model M1 is additively designed, and a machining allowance of 0.5-1.5mm is added to its exterior to form a 3D printed hollow blade blank part model M2. Then, a spiral crystal selector structure 3D model X1 is designed at the bottom center of model M2, and combined to form a 3D printed hollow blade model Y1. The spiral crystal selector has a pitch of 20-35mm, a diameter of 10-30mm, a wire diameter of 4-6mm, a helix angle of 35-70°, and 1-3 spiral turns, so that the main orientation of the obtained single crystal is in the

[001] direction. Model Y1 is sliced, and the slice layer thickness is 0.03-0.3mm to obtain the 3D printed hollow blade data parameters Y2. The data parameters Y2 are imported into the electron beam 3D printer.

[0045] (7) Set up the electron beam 3D printer for printing preparation and processing: Evacuate to ≤0.3Pa, set the preheating temperature parameters to 1000~1300℃, and the holding time to 30min; set the solid part printing parameters: electron beam current 25~48mA, scanning speed 5-15m / s; until printing is completed, the vacuum will naturally cool to room temperature with the furnace.

[0046] (8) Due to the long-term preheating and sintering of the powder at high temperature, the powder has already shown a pseudo-sintered state, forming sintered bricks, and the parts are in the sintered bricks. The sintered bricks are transported to the electron beam powder recovery equipment, and 1kg of Ni-based alloy powder F2 is pre-placed in the equipment. The equipment is similar to a sandblasting machine. After the equipment door is sealed, the spraying is started. Ni-based alloy powder F2 is sprayed out from the spray gun under high pressure, spraying the sintered bricks and gradually breaking up the bricks to form recovered Ni-based alloy powder F3. Finally, the Ni-based alloy hollow blade blank Z1 is taken out.

[0047] (9) Place the Ni-based alloy hollow blade blank Z1 into a high-vacuum heat treatment furnace for solution treatment and aging treatment. The parameters are: reduce the pressure inside the furnace to 10. -3 Pa, then set the heat treatment temperature and time parameters, starting from 20℃ (room temperature), heating to 1000℃ at a heating rate of 10℃ / min, heating to 1300±5℃ at a heating rate of 5℃ / min, and then heating to 1350±5℃ at a heating rate of 2.5℃ / min, with a holding time of 10h~20h. After the heat preservation period, 99.999% high-purity argon gas is slowly introduced into the furnace, and the furnace blower is started. Argon gas is introduced until the furnace pressure reaches 90 kPa, at which point the argon gas introduction is stopped. Cooling is then started at a cooling rate of 2.5℃ / s to 50℃. Immediately afterwards, the furnace temperature is increased from 50℃ to 870-920℃ at a heating rate of 10℃ / min, and the temperature is maintained for 12-30 hours. After the heat preservation period, 99.999% high-purity argon gas is slowly introduced into the furnace, and the furnace blower is started. Argon gas introduction is stopped until the furnace pressure reaches 90 kPa, at which point the argon gas introduction is stopped. Cooling is then started at a cooling rate of 2.5℃ / s to 50℃. The furnace door is then opened, and the Ni-based alloy hollow blade blank Z2, which has undergone solution treatment and aging treatment, is removed.

[0048] (10) According to the blade design drawings, the Ni-based alloy hollow blade blank Z2, which has undergone solution treatment and aging treatment, is machined to remove the surface machining allowance. The cutting speed is 400-1600 r / min, the feed rate is 200-1200 mm / min, and the cutting width is 4-10 mm to obtain the machined Ni-based alloy hollow blade Z3.

[0049] (11) The machined Ni-based alloy hollow blade Z3 was subjected to plasma polishing to remove the surface defect layer. The plasma solution formula was ammonium sulfate: sodium citrate: distilled water = (1-5):(0.5-2.5):100. The polishing temperature was 75℃, the polishing voltage was 250-350V, and the polishing time was 2-10min. Finally, Ni-based single crystal hollow blade Z4 with a surface roughness Ra < 0.8μm and dimensional accuracy meeting the drawing requirements was obtained.

[0050] This invention employs a complete manufacturing process to develop high-purity Ni-based superalloy powder and fabricate Ni-based single-crystal superalloy hollow blades using electron beam selective 3D printing. The fabricated Ni-based single-crystal alloy blades undergo surface material removal (1 mm), ultimately yielding the Ni-based single-crystal alloy blade. Domestic and international methods for preparing Ni-based single-crystal alloys mainly include seed crystal methods and non-seed crystal methods, both employing casting techniques. Seed crystal methods suffer from significant limitations due to their complex manufacturing process, difficulty in seed crystal preparation, and extreme difficulty in preparing large-sized seed crystals. Only alloys with α-phase in the primary solidification phase can be prepared using seed crystal methods for single-crystal fabrication. Non-seed crystal methods suffer from crucible material contamination of the alloy, as well as difficulties in mold shell preparation and low yield. This invention belongs to the additive manufacturing method for preparing Ni-based single-crystal hollow blades, enabling the manufacture of complex structures, large-size parts, high efficiency, high microstructure uniformity, high purity, and high yield.

[0051] Ni-based single-crystal superalloys are mainly used to manufacture hot-end turbine blades for aero engines and gas turbines. Their heat resistance is a key technical indicator for improving engine performance, efficiency, and reliability. Ni-based single-crystal superalloys have evolved to the fourth and fifth generation alloys with service temperatures exceeding 1100℃. The structure of single-crystal blades is also becoming increasingly complex. For example, single-crystal hollow blades with high-efficiency cooling typically have hundreds of film cooling pores on the blade body. They are usually processed using electrohydraulic beam or electrical discharge machining (EDM), but the processing efficiency is low, making it difficult to meet the needs of engineering mass production. Furthermore, because a remelted layer exists on the surface of the hole after EDM drilling, subsequent electrolytic methods are used to remove the remelted layer. However, insufficient electrolyte filling at the hole wall results in the incomplete removal of the remelted layer, leading to a yield of less than 10% for single-crystal hollow blades.

[0052] This invention develops a high-purity Ni-based superalloy powder using a complete process preparation method, and then prepares Ni-based superalloy hollow blades in an electron beam selective 3D printing device. After removing 1 mm of material from the surface of the prepared Ni-based alloy blades, Ni-based single-crystal alloy blades are finally obtained. The yield is high (over 90%), and the creep life at high temperature (1100℃ / 137MPa) is 49% higher than that of traditionally processed parts, showing good feasibility and application prospects for promotion and application.

[0053] Taking Ni-based single-crystal high-temperature alloy hollow blades for engines and gas turbines as an example, the technology of this invention can significantly improve the yield and performance of Ni-based single-crystal high-temperature alloy hollow blades, greatly improve the development progress of new models and new products, shorten the research and development and production cycle, reduce production costs, and has broad market potential.

[0054] Example 2

[0055] In this embodiment, a method for manufacturing Ni-based single-crystal superalloy hollow blades using electron beam selective 3D printing includes the following steps:

[0056] (1) Select pure metal raw materials with a purity of 99.999% and formulate them according to the alloy composition. The chemical composition of the alloy is calculated by weight percentage as follows: Cr: 3.0%; Co: 5.6%; Mo: 2.8%; W: 5.6%; Ta: 5.6%; Al: 5.6%; Re: 6.9%; Ru: 5.0%; Hf: 0.1%; and the remainder is Ni.

[0057] (2) When the vacuum degree is less than 10 -3 The master alloy was smelted in a water-cooled copper crucible suspension smelting furnace at a temperature of 1650℃ for 10 minutes. The alloy composition was homogenized by two smelting processes. A melting mold shell made of CaO was then used to cast Ni-based alloy rod B1. The obtained Ni-based alloy rod B1 has a size of 71×290mm. After machining, it was made into Ni-based alloy rod B2 with a size of 70×285mm and a surface roughness Ra of 0.67μm.

[0058] (3) Load the Ni-based alloy rod B2 into the plasma rotating electrode device and carry out Ni-based alloy powder preparation under vacuum. The electrode rotation speed is 18500 r / min and the plasma arc current is 2250 A. After sieving, spherical Ni-based alloy powder F1 with a particle size distribution of 50-175 μm is obtained.

[0059] (4) The obtained Ni-based alloy powder F1 is loaded into a vacuum plasma cleaning equipment for argon ion cleaning. A mixed gas medium of H2:Ar2 = 1:1 is selected, the power is 240W, and the time is 3 minutes. After the treatment, the powder is sieved to obtain spherical Ni-based alloy powder F2 of 45-155μm, which is used for electron beam selective melting 3D printing.

[0060] (5) Load a sufficient amount of Ni-based alloy powder F2 into the powder storage box of the electron beam 3D printer;

[0061] (6) The hollow blade 3D model M1 is additively designed, and a 1mm machining allowance is added to its entire exterior to form a 3D printed hollow blade blank part model M2. Then, a spiral crystal selector structure 3D model X1 is designed at the bottom center of model M2, and combined to form a 3D printed hollow blade model Y1. The spiral crystal selector has a pitch of 25mm, a diameter of 20mm, a wire diameter of 5mm, a helix angle of 45°, and 1 spiral turn, so that the main orientation of the obtained single crystal is in the

[001] direction. Model Y1 is sliced, and the slice layer thickness is 0.04mm to obtain the 3D printed hollow blade data parameters Y2. The data parameters Y2 are imported into the electron beam 3D printer.

[0062] (7) Set up the electron beam 3D printer for printing preparation and processing: Evacuate to ≤0.3Pa, set the preheating temperature parameter to 1030℃, and the holding time to 30min; set the part solid printing parameters: electron beam current 46mA, scanning speed 6.5m / s; until printing is completed, the vacuum will naturally cool to room temperature with the furnace.

[0063] (8) Due to the long-term preheating and sintering of the powder at high temperature, the powder has already shown a pseudo-sintered state, forming sintered bricks, and the parts are in the sintered bricks. The sintered bricks are transported to the electron beam powder recovery equipment, and 1kg of Ni-based alloy powder F2 is pre-placed in the equipment. The equipment is similar to a sandblasting machine. After the equipment door is sealed, the spraying is started. Ni-based alloy powder F2 is sprayed out from the spray gun under high pressure, spraying the sintered bricks and gradually breaking up the bricks to form recovered Ni-based alloy powder F3. Finally, the Ni-based alloy hollow blade blank Z1 is taken out.

[0064] (9) Place the Ni-based alloy hollow blade blank Z1 into a high-vacuum heat treatment furnace for solution treatment and aging treatment. The parameters are: reduce the pressure inside the furnace to 10. -3 Pa, then set the heat treatment temperature and time parameters, starting from 20℃ (room temperature), heating to 1000℃ at a heating rate of 10℃ / min, heating to 1300±5℃ at a heating rate of 5℃ / min, and then heating to 1350±5℃ at a heating rate of 2.5℃ / min, and holding for 18h. After the heat preservation period, 99.999% high-purity argon gas is slowly introduced into the furnace, and the furnace blower is started. Argon gas is introduced until the furnace pressure reaches 90 kPa, at which point the argon gas introduction is stopped. Cooling is then started at a cooling rate of 2.5℃ / s to 50℃. Immediately afterwards, the furnace temperature is increased from 50℃ to 900℃ at a heating rate of 10℃ / min, and the temperature is maintained for 12-30 hours. After the heat preservation period, 99.999% high-purity argon gas is slowly introduced into the furnace, and the furnace blower is started. Argon gas introduction is stopped until the furnace pressure reaches 90 kPa, at which point the argon gas introduction is stopped. Cooling is then started at a cooling rate of 2.5℃ / s to 50℃. The furnace door is then opened, and the Ni-based alloy hollow blade blank Z2, which has undergone solution treatment and aging treatment, is removed.

[0065] (10) According to the blade design drawings, the Ni-based alloy hollow blade blank Z2, which has undergone solid solution treatment and aging treatment, is machined to remove the surface machining allowance. The cutting speed is 800 r / min, the feed rate is 400 mm / min, and the cutting width is 5 mm to obtain the machined Ni-based alloy hollow blade Z3.

[0066] (11) The machined Ni-based alloy hollow blade Z3 was subjected to plasma polishing to remove the surface defect layer. The plasma solution formula was ammonium sulfate: sodium citrate: distilled water = 3:1.5:100. The polishing temperature was 75℃, the polishing voltage was 290V, and the polishing time was 3min. Finally, Ni-based single crystal hollow blade Z4 with a surface roughness Ra of 0.3μm and dimensional accuracy meeting the drawing requirements was obtained.

[0067] Using the same powder and process as Ni-based single-crystal hollow blades, Ni-based single-crystal mechanical tensile specimens (R7) were processed in the same furnace, and high-temperature creep tests were conducted. The results showed that the Ni-based single-crystal specimens exhibited a creep stress of 137 MPa and a creep life of 1074 h at 1100 °C. Compared with traditional Ni-based single-crystal materials (137 MPa and 721 h), the creep life was improved by more than 49%, demonstrating a significant performance improvement. The yield of Ni-based single-crystal hollow blades exceeded 90%, higher than the yield of traditional processing (approximately 10%). Therefore, the high-temperature performance of the Ni-based single-crystal hollow blades prepared by this invention is significantly superior to that of traditional processing methods, which is beneficial for promoting the widespread application of Ni-based single-crystal materials / parts.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing Ni-based single-crystal superalloy hollow blades using selective electron beam 3D printing, characterized in that, Includes the following steps: Step 1: The proportioned alloy raw materials are placed in a water-cooled copper crucible induction melting furnace for melting, and Ni-based alloy rod B2 is obtained by casting and machining. Step 2: Prepare spherical Ni-based alloy powder F1 from Ni-based alloy rod B2 using the plasma rotating electrode method; Step 3: Clean and sieve the spherical Ni-based alloy powder F1 to obtain spherical Ni-based alloy powder F2, and load the spherical Ni-based alloy powder F2 into the powder storage box of the electron beam 3D printer. Step 4: Perform additive design on the hollow blade model, set printer parameters, and perform electron beam selective 3D printing; Step 5: After electron beam selective 3D printing is completed, the powder is recycled to obtain Ni-based alloy hollow blade blank Z1; Step 6: Perform solution treatment and aging treatment on the Ni-based alloy hollow blade blank Z1 to obtain the Ni-based alloy hollow blade blank Z2; Step 7: Machining the Ni-based alloy hollow blade blank Z2 to obtain the Ni-based alloy hollow blade Z3; Step 8: Plasma polishing is performed on the Ni-based alloy hollow blade Z3 to obtain a Ni-based single crystal high-temperature alloy hollow blade. In step three, Ni-based alloy powder F1 is loaded into a vacuum plasma cleaning device, using a mixed gas medium of H2:Ar2=1:1, with a power of 210-270W and a time of 1-10 minutes for argon ion cleaning; after cleaning, Ni-based alloy powder F1 is sieved to obtain spherical Ni-based alloy powder F2 with a particle size distribution of 45~155μm. In step four, the additive design method is as follows: A machining allowance of 0.5~1.5mm is added to the outside of the hollow blade 3D model M1 to form a 3D printed hollow blade blank part model M2. A spiral crystal selector structure 3D model X1 is designed at the center of the bottom of the 3D printed hollow blade blank part model M2. The 3D printed hollow blade blank part model M2 and the spiral crystal selector structure 3D model X1 are combined to form a 3D printed hollow blade model Y1. The spiral crystal selector has a pitch of 20-35mm, a diameter of 10-30mm, a wire diameter of 4-6mm, a helix angle of 35-70°, and 1-3 spiral turns, so that the main orientation of the obtained single crystal is in the [001] direction. The 3D printed hollow blade model Y1 is sliced, with a slice layer thickness of 0.03~0.3mm, to obtain the 3D printed hollow blade data parameters Y2. The 3D printed hollow blade data parameters Y2 are then imported into an electron beam 3D printer. The parameters for the electron beam 3D printer include: vacuuming to ≤0.3Pa, preheating temperature set to 1000~1300℃, and holding time of 30min; the parameters for printing the solid part are: electron beam current of 25~48mA and scanning speed of 5-15m / s; after printing, the vacuum is allowed to cool naturally to room temperature with the furnace.

2. The method for manufacturing Ni-based single-crystal high-temperature alloy hollow blades by selective electron beam 3D printing according to claim 1, characterized in that, In step one, the alloy raw materials are all pure metal raw materials with a purity of 99.999%, containing the following components in parts by weight: Cr: 2.0-4.6%; Co: 0.2~16.5%; Mo: 1.0~3.9%; W: 5.0~6.0%; Ta: 5.0~8.25%; Al: 5.5~6.0%; Re: 4.0–6.9%; Ru: 2.0–6.0%, Hf: 0.1%, the remainder being Ni.

3. The method for manufacturing Ni-based single-crystal superalloy hollow blades by selective electron beam 3D printing according to claim 1, characterized in that, In step one, the vacuum level is less than 10. -3 The master alloy is smelted in a water-cooled copper crucible induction levitation melting furnace at a temperature of 1550-1750℃ for 5-15 minutes. The alloy composition is homogenized by 1-5 meltings. A Ni-based alloy rod B1 is cast into a melting mold shell made of CaO. The size of the Ni-based alloy rod B1 is 71×290mm. After machining, a Ni-based alloy rod B2 with a size of 70×285mm and a surface roughness Ra<0.8μm is made.

4. The method for manufacturing Ni-based single-crystal superalloy hollow blades by selective electron beam 3D printing according to claim 1, characterized in that, In step two, the plasma rotating electrode method uses a plasma rotating electrode powder preparation device. The Ni-based alloy rod B2 is loaded into the plasma rotating electrode powder preparation device, and the electrode rotation speed is set to 16000-25000 r / min and the plasma arc current is 1500-2600 A. Ni-based alloy powder is prepared under vacuum. After preparation, spherical Ni-based alloy powder F1 with a particle size distribution of 50~175μm is obtained by sieving.

5. The method for manufacturing Ni-based single-crystal superalloy hollow blades by selective electron beam 3D printing according to claim 1, characterized in that, In step six, the Ni-based alloy hollow blade blank Z1 is placed in a high-vacuum heat treatment furnace for solution treatment and aging treatment, specifically including the following steps: The pressure inside the high-vacuum heat treatment furnace was reduced to 10. -3 Pa, heat treatment: starting from room temperature of 20℃, heat up to 1000℃ at a heating rate of 10℃ / min, then heat up to 1300±5℃ at a heating rate of 5℃ / min, then heat up to 1350±5℃ at a heating rate of 2.5℃ / min, and hold at 1350±5℃ for 10h~20h. After the heat preservation period, high-purity argon gas with a purity of 99.999% is slowly introduced into the furnace, and the furnace blower is started. The high-purity argon gas is stopped when the furnace pressure reaches 90 kPa. Cooling begins at a cooling rate of 2.5℃ / s to 50℃. Then, starting from the furnace temperature of 50℃, the temperature is increased to 870-920℃ at a heating rate of 10℃ / min and held for 12-30 hours. After the heat preservation period, high-purity argon gas with a purity of 99.999% is slowly introduced into the furnace, and the furnace blower is started. The high-purity argon gas is stopped when the furnace pressure reaches 90 kPa. Cooling begins at a cooling rate of 2.5℃ / s to 50℃. The furnace door is opened, and the Ni-based alloy hollow blade blank Z2, which has undergone solution treatment and aging treatment, is taken out.

6. The method for manufacturing Ni-based single-crystal high-temperature alloy hollow blades by selective electron beam 3D printing according to claim 1, characterized in that, In step seven, the cutting speed of the machining is 400~1600 r / min, the feed rate is 200~1200 mm / min, and the cutting width is 4~10 mm, in order to remove the surface machining allowance.

7. The method for manufacturing Ni-based single-crystal superalloy hollow blades by selective electron beam 3D printing according to claim 1, characterized in that, In step eight, the plasma polishing temperature is 75℃, the polishing voltage is 250-350V, and the polishing time is 2-10min. The plasma polishing is performed using a plasma solution composed of ammonium sulfate, sodium citrate, and distilled water, with the ratio of ammonium sulfate:sodium citrate:distilled water being (1-5):(0.5-2.5):

100. The surface roughness Ra of the Ni-based single-crystal high-temperature alloy hollow blade is <0.8μm.

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