Aluminum-based alloy powder for additive manufacturing and method for producing the same

Abstract

This invention relates to the field of additive manufacturing materials technology, specifically to an aluminum-based alloy powder for additive manufacturing and its preparation method. The preparation method of the aluminum-based alloy powder for additive manufacturing includes: using recycled aluminum as raw material, after pretreatment, batching, and smelting, adding a composite refining agent for refining, degassing, and slag removal, followed by semi-continuous casting to obtain a master alloy; placing the master alloy in an induction melting furnace for induction remelting to obtain a molten master alloy; introducing the molten master alloy through a liquid guide pipe into a ring-hole type tightly coupled atomizer for supersonic vacuum atomization, followed by sieving and classification to obtain aluminum-based alloy powder. This application features a compact process flow, requires no complex high-end equipment, is compatible with mainstream additive manufacturing equipment such as Concept Laser and EOS, reduces production costs by more than 30%, and is suitable for additive manufacturing of large and complex components in aerospace, automotive, and transportation fields.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing materials technology, specifically to an aluminum-based alloy powder for additive manufacturing and its preparation method. Background Technology

[0002] Aluminum-based alloy powders, due to their low density, high specific strength, and excellent corrosion resistance, have become one of the core raw materials in the additive manufacturing field, especially in the manufacture of lightweight components, where they possess irreplaceable advantages. However, existing aluminum-based alloy powder preparation technologies for additive manufacturing face several bottlenecks: on the one hand, the smelting process of the master alloy is complex and costly, and inclusions and gases in waste aluminum raw materials are difficult to remove effectively, resulting in high oxygen content and numerous inclusions in the powder, which seriously affects the mechanical properties of additively manufactured components; on the other hand, the traditional atomizing nozzle structure design is unreasonable, and the matching between airflow velocity and liquid flow atomization is poor, resulting in low powder sphericity, high defect rates of hollow powder and satellite powder, and a yield of less than 60% in the 10~53μm narrow particle size range; in addition, foreign high-end aluminum-based alloy powders monopolize the market and are expensive, while domestic products suffer from poor batch stability and substandard performance, which restricts the industrialization development of additive manufacturing technology in my country.

[0003] Existing technologies mostly focus on improving single steps, such as optimizing atomization pressure or improving refining agent formulations, but they fail to form a synergistic control system for the entire process of "master alloy preparation - atomization powder production - sieving and classification," making it difficult to simultaneously address the needs of powder quality, production efficiency, and cost control. Therefore, developing an integrated preparation method that combines low-cost master alloy smelting, efficient atomization, and precise classification to achieve the domestic production and low-cost manufacturing of high-quality aluminum-based alloy powders has significant engineering value and market prospects. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing aluminum-based alloy powder for additive manufacturing, which solves the problems of low purity, many inclusions, insufficient sphericity and high cost of aluminum-based alloy powder in the prior art.

[0005] The present invention also provides an aluminum-based alloy powder for additive manufacturing, which solves the problems of low purity, many inclusions and insufficient sphericity of aluminum-based alloy powder in the prior art.

[0006] To address the aforementioned problems, this invention proposes a method for preparing aluminum-based alloy powder for additive manufacturing. The technical solution adopted is as follows: A method for preparing aluminum-based alloy powder for additive manufacturing includes the following steps: Step 1: Using recycled aluminum as raw material, after pretreatment, batching, electric furnace / gas furnace smelting, alloying treatment, a composite refining agent is added for refining, degassing and slag removal, and then after slag removal, static refining and semi-continuous casting, a master alloy with hydrogen content ≤0.09µg / gAl and inclusion content ≤0.035mm² / kg is obtained. Step 2: Place the master alloy in an induction melting furnace for induction remelting to obtain a molten master alloy. Step 3: After the molten master alloy is introduced into the annular tightly coupled atomizer through the liquid guide tube for supersonic vacuum atomization, it is then sieved and classified to obtain aluminum-based alloy powder.

[0007] The beneficial effects of this invention are as follows: This invention is an improved invention. It uses recycled aluminum as raw material and processes it through a complete process of "pretreatment-batching-smelting-alloying treatment-refining-slag removal-static refining-semi-continuous casting" to obtain a master alloy. Using recycled aluminum as raw material reduces production costs. The composite refining agent achieves a synergistic effect of degassing, slag removal, and inclusion modification, preparing a master alloy with high cleanliness and uniform structure. The obtained master alloy has a hydrogen content ≤0.9µg / g Al and an inclusion content ≤0.035mm² / kg, significantly improving powder purity and solving the problems of low purity and high cost of master alloy in traditional processes. Furthermore, the use of supersonic gas atomization technology efficiently crushes and rapidly solidifies the master alloy, preparing aluminum-based alloy powder with low defects, high sphericity, and high adaptability. The powder yield is ≥95.8%, significantly improving powder purity and output. Ultimately, it achieves the dual goals of "recycled aluminum resource utilization" and "high-quality powder for additive manufacturing," taking into account both economy and practicality, and expanding the high-end application scenarios of recycled aluminum.

[0008] The method for preparing aluminum-based alloy powder for additive manufacturing disclosed in this application features fully quantifiable and controllable process parameters, ensuring batch-to-batch powder stability and compatibility with mainstream additive manufacturing equipment. Furthermore, the process flow is compact, requiring no complex high-end equipment, and is compatible with mainstream additive manufacturing equipment such as Concept Laser and EOS, reducing production costs by more than 30%. It is suitable for additive manufacturing of large and complex components in aerospace, automotive, and transportation fields, demonstrating significant technological innovation and industrialization value. Moreover, the use of recycled aluminum raw materials aligns with resource recycling and carbon emission reduction policies, possessing broad prospects for industrialization and promotion, and is of great significance for promoting the localization of additive manufacturing technology in my country.

[0009] Preferably, the ingredients are: The pretreated recycled aluminum and alloying elements are proportioned according to the AlSi10Mg or AlSi12 alloy composition ratio. By using the AlSi10Mg or AlSi12 composition ratio for the pretreated recycled aluminum and alloying elements, the alloy composition can be precisely controlled, ensuring uniform distribution of alloying elements. This results in a stable master alloy composition and uniform microstructure, providing a stable raw material basis for the subsequent gas atomization preparation of powders with high sphericity and low defects. This is beneficial for improving the batch stability of powders and the mechanical properties of additive manufacturing products.

[0010] Preferably, the low-magnification microstructure of the master alloy is free of inclusions, and the size of the inclusions in the microstructure is ≤50µm, wherein the number of inclusions of 20~50µm is ≤5 per cm².

[0011] Preferably, the melting temperature is 720~780℃; the refining temperature is 720~750℃, and the time is 40~60min; the standing refining time is 20~30min. By controlling the melting temperature at 720~780℃, the waste aluminum raw material can be melted quickly and uniformly, avoiding insufficient melting and component segregation due to excessively low temperature, while preventing excessively high temperature from aggravating aluminum melt oxidation, gas absorption, and grain coarsening; setting the refining temperature at 720~750℃ and the refining time at 40~60min ensures that the composite refining agent reacts fully with the melt, achieving deep removal of gases, inclusions, and alkaline earth metals; the standing refining time of 20~30min is conducive to the full floating and aggregation of residual bubbles and fine flux inclusions, further improving the cleanliness of the melt and providing a high-purity melt for subsequent atomization powder production.

[0012] Preferably, the composite refining agent is composed of the following components by mass percentage: NaCl 30-40%, Na3AlF6 25-35%, CaF2 15-20%, and CeO2 3-8%; the amount of the composite refining agent added is 0.8-1.2% of the mass of the melt after smelting. Through the physicochemical reaction between the composite refining agent and the melt, degassing, slag removal, and inclusion modification are achieved. Using a composite refining agent composed of NaCl, Na3AlF6, CaF2, and CeO2, the components work synergistically to significantly reduce the surface tension of the melt, efficiently adsorb oxidized inclusions, remove dissolved hydrogen, and neutralize harmful impurities. Specifically, NaCl and Na3AlF6 reduce the surface tension of the melt, promoting the floating of bubbles and inclusions; CaF2 adsorbs oxide inclusions; and CeO2 further purifies the melt and improves the morphology of inclusions, achieving synergistic optimization of degassing and slag removal.

[0013] More preferably, the composite refining agent is composed of the following components by mass percentage: NaCl 35~38%, Na3AlF6 28~30%, CaF2 16~18%, CeO2 7~8%.

[0014] Preferably, the semi-continuous casting parameters are: casting speed 0.8~1.5m / min, cooling water flow rate 5~8m³ / h; and the diameter of the master alloy is 150~300mm. Semi-continuous casting can achieve a uniform and dense ingot structure with fine grains, avoiding defects such as cracking, shrinkage cavities, and segregation caused by excessive or insufficient cooling. Stable casting parameters can ensure that the master alloy ingot has a uniform composition and clean interior, providing a master alloy raw material with a uniform structure and excellent flowability for subsequent atomization powder production, thus improving powder quality from the source.

[0015] Preferably, the induction remelting temperature is 750~900℃, and the time is 15~25min; the induction remelting is performed under a vacuum degree ≤1×10 - The process is carried out under ³Pa conditions. Melting and holding the master alloy at 750~900℃ for 15~25 min ensures complete melting, homogeneous composition, and melt flowability that meets atomization requirements; under a vacuum degree ≤1×10 - Melting at ³Pa can significantly reduce the hydrogen and oxygen content of the melt, suppress high-temperature oxidation, greatly reduce defects such as hollow powder and oxide inclusions, and significantly improve the high purity requirements of aluminum-based powders for additive manufacturing.

[0016] Preferably, during the supersonic vacuum atomization process, dual-beam detection technology is used to monitor the powder morphology in real time, controlling the satellite powder defect rate to ≤0.15‰ and the hollow powder rate to ≤0.23‰. The real-time monitoring of powder morphology during atomization using dual-beam detection technology allows for online identification and dynamic process adjustment, achieving closed-loop defect control. Maintaining a satellite powder defect rate of ≤0.15‰ and a hollow powder rate of ≤0.23‰ significantly improves powder sphericity, flowability, and bulk density, meeting the stringent requirements of additive manufacturing for high powder consistency and low defects, and enhancing the density and mechanical stability of printed parts.

[0017] Preferably, the number of annular holes in the tightly coupled atomizer is 12-32, the spray apex angle is 35-55°, and the ratio of the annular hole diameter to the pitch circle diameter is (0.3-1.5):(55-75). The liquid guide tube is made of graphite, and the ratio of the inner diameter of the liquid guide tube to the annular hole diameter is (8-12):(0.3-1.5). The distance between the outlet of the liquid guide tube and the spray plane of the tightly coupled atomizer is 8-12 mm, and the coaxiality deviation between the liquid guide tube and the tightly coupled atomizer is ≤0.5 mm. A reasonable ratio of the number, angle, and size of the holes allows the high-pressure airflow to form a stable, symmetrical, and highly convergent atomization field, significantly improving the airflow velocity and liquid flow breaking efficiency. This enables efficient melt breaking, ensures concentrated powder particle size distribution and high sphericity, reduces the proportion of irregular and coarse powder, and improves the powder's flowability and spreading performance suitable for additive manufacturing. In use, this structure, combined with supersonic gas atomization technology, achieves a powder sphericity ≥95.5%, a 10~53μm particle size ratio ≥65%, and a yield of qualified products ≥95.8%, overcoming the bottlenecks of low fine powder yield and poor powder morphology in traditional atomization technology. The ratio of the inner diameter of the graphite liquid guide tube to the diameter of the annular hole is (8~12):(0.3~1.5); the distance between the liquid guide tube outlet and the spray plane of the annular hole-type tightly coupled atomizer is 8~12mm; the liquid guide tube is made of graphite, and the coaxiality deviation between the liquid guide tube and the annular hole-type tightly coupled atomizer is ≤0.5mm. It can achieve precise coupling of airflow and melt flow; it can avoid airflow backflow causing blockage of the liquid guide tube and melt splashing, and ensure that the melt is efficiently broken up at the optimal position, further improving powder sphericity, reducing satellite balls, hollow powder, and flash defects, and improving powder yield and quality stability. The liquid guide tube is made of graphite, which is resistant to high temperatures, does not chemically react with the aluminum alloy melt, is not prone to aluminum adhesion, and does not contaminate the melt. At the same time, it has good thermal shock stability, which can ensure stable melt flow and avoid high-temperature cracking. The coaxiality deviation between the liquid guide tube and the annular tightly coupled atomizer is controlled to ≤0.5mm, which can ensure precise alignment and symmetrical coupling between the melt flow and the supersonic airflow. This avoids uneven melt breakage, local overspray, or insufficient atomization caused by flow deviation, thereby significantly improving the consistency of powder sphericity, reducing satellite powder, irregular powder, and hollow powder defects, improving powder flowability and yield, and ensuring batch stability of powders for additive manufacturing.

[0018] Preferably, the sieving and grading is carried out under an ambient humidity of ≤40% to obtain aluminum-based alloy powder with a particle size range of 10-53μm, such that the proportion of aluminum-based alloy powder in this particle size range is ≥65%.

[0019] Preferably, the process of supersonic gas atomization technology is as follows: Argon gas with a purity ≥99.99% is used as the atomizing gas. The gas is preheated to 120~180℃, the atomization pressure is 4~7MPa, and the pressure rise rate of the atomization canister is ≤0.67Pa / h. The atomized powder is collected by a cyclone separation and collection system. Using argon gas with a purity ≥99.99% and preheating it to 120~180℃ reduces the temperature difference between the melt and the gas, avoiding morphological defects caused by rapid powder solidification. The atomization pressure is controlled at 4~7MPa to ensure the gas outlet velocity reaches supersonic speed, guaranteeing that the molten metal flow is fully broken into fine droplets.

[0020] This invention also proposes an aluminum-based alloy powder for additive manufacturing, the technical solution of which is as follows: An aluminum-based alloy powder for additive manufacturing is prepared by the above-described method for preparing aluminum-based alloy powder for additive manufacturing. The performance indicators of the qualified product of the aluminum-based alloy powder for additive manufacturing are as follows: oxygen content ≤290ppm, nitrogen content ≤190ppm, sphericity ≥95.5%, Hall flow rate ≤35s / 50g, loose packing density ≥1.48g / cm³, tap density ≥2.08g / cm³; and the yield of the qualified product is ≥95.8%.

[0021] The beneficial effects of the present invention are: the aluminum-based alloy powder for additive manufacturing prepared by the method of the present invention has low defects, high sphericity, and high adaptability, significantly improving powder purity and yield, and ultimately achieving the dual goals of "recycled aluminum resource utilization" and "high quality powder for additive manufacturing", taking into account both economy and practicality. Detailed Implementation

[0022] Existing technologies for aluminum-based alloy powders suffer from low purity, numerous inclusions, insufficient sphericity, and high cost. This invention proposes a method for preparing aluminum-based alloy powders for additive manufacturing with ferroelectric properties, comprising the following steps: Step 1: Using recycled aluminum as raw material, after pretreatment, batching, electric furnace / gas furnace smelting, alloying treatment, compound refining agent is added for refining, and then after slag removal, static refining and semi-continuous casting, a master alloy with hydrogen content ≤0.09µg / g Al and inclusion content ≤0.035mm² / kg is obtained. Step 2: Place the master alloy in an induction melting furnace for induction remelting to obtain a molten master alloy; Step 3: After the molten master alloy is introduced into the annular tightly coupled atomizer through the liquid guide tube for supersonic vacuum atomization, it is then sieved and classified to obtain aluminum-based alloy powder.

[0023] The technical concept of this invention is as follows: First, recycled aluminum is used as the core raw material to replace traditional primary aluminum, significantly reducing raw material costs while aligning with resource recycling and carbon emission reduction policies. Second, pretreatment removes oil, moisture, and impurities from the recycled aluminum, and precise control of alloy composition is achieved through batching. Temperature and time are controlled during the smelting process to ensure complete melting and uniform composition of the raw materials. After the raw materials are completely melted, alloying treatment is performed to precisely adjust the alloy composition to the target requirements. Then, through the physicochemical reaction between the composite refining agent and the melt, deep degassing and slag removal are achieved, thoroughly removing hydrogen, oxide inclusions, and harmful impurities from the melt, solving the core problem of low cleanliness in recycled aluminum melt. After slag removal and static refining, residual inclusions are floated to the surface. Finally, a master alloy with a dense structure, uniform composition, and no obvious defects is obtained through semi-continuous casting, providing a high-quality base material for subsequent atomization powder production and fundamentally avoiding powder defects caused by poor master alloy quality.

[0024] After the master alloy is melted, the high-speed airflow of supersonic gas atomization breaks the molten master alloy into fine droplets. The droplets are then rapidly cooled and solidified to form alloy powder. Compared with traditional atomization technology, supersonic gas atomization can achieve rapid droplet breakage and rapid cooling, effectively reducing defects such as hollow powder and satellite powder, and improving the sphericity and uniformity of powder size distribution. At the same time, by matching the master alloy melting parameters and atomization process parameters, the powder is ensured to have excellent flowability, loose density and chemical composition consistency, fully meeting the stringent requirements of additive manufacturing for powder (uniform powder spreading, high printing density and stable mechanical properties).

[0025] The method for preparing aluminum-based alloy powder for additive manufacturing of the present invention adopts a whole process of "low-cost and high-cleanliness master alloy preparation - high-efficiency tight-coupled supersonic gas atomization - precise sieving and classification", innovatively designs a ring hole type tight-coupled atomizer structure, and optimizes the master alloy smelting and atomization process parameters to achieve low-cost and stable production of AlSi10Mg / AlSi12 alloy powder.

[0026] The method for preparing aluminum-based alloy powder for additive manufacturing of the present invention constructs an integrated preparation concept of "recycled aluminum resource utilization + precise quality control throughout the process", realizing the core goal of "low cost, high purity, low defect and high adaptability" of aluminum-based alloy powder for additive manufacturing, and providing aluminum-based alloy powder with stable performance and high cost performance for the additive manufacturing field to promote the resource application of recycled aluminum in high-end additive manufacturing.

[0027] Specifically, the method for preparing aluminum-based alloy powder for additive manufacturing includes the following steps: (1) Preparation of high-purity homogenized master alloy: The process route of “recycled aluminum pretreatment - batching and charging - electric furnace / gas furnace smelting - alloying - refining - slag removal - static refining - semi-continuous casting - ingot surface cleaning” is adopted. The furnace purification treatment, composition adjustment and degassing are carried out in sequence. The refining temperature is controlled at 720~780℃, the refining time is 40~60min, and the static time is 20~30min. A composite refining agent is added during the refining process. Its mass composition is: NaCl 30~40%, Na3AlF6 25~35%, CaF2 15~20%, CeO2 3~8%, and the addition amount is 0.8~1.2% of the melt mass. Finally, AlSi10Mg / AlSi12 master alloy is obtained. (2) High-efficiency tight-coupled supersonic gas atomization: The master alloy obtained in step (1) is placed in an induction melting furnace, and the vacuum degree is ≤1×10 - The mixture is heated to 750~900℃ under ³Pa conditions and remelted. After holding at this temperature for 15~25 min, it is introduced into a ring-hole type tightly coupled atomizer through a liquid guide tube. The atomizer has 12~32 ring holes with a diameter of 0.3~1.5 mm, a spray apex angle of 35~55°, a pitch circle diameter of 55~75 mm, and a distance of 8~12 mm between the outlet of the liquid guide tube and the spray plane of the atomizer. Argon gas with a purity of ≥99.99% is used as the atomizing gas. The gas is preheated to 120~180℃, the atomization pressure is 4~7 MPa, and the pressure rise rate of the atomizing tank is ≤0.67 Pa / h. The atomized powder is collected by a cyclone separation and collection system. (3) Precise screening and grading: In a dry environment with humidity ≤40%, a multi-stage vibrating screening process is adopted, and aluminum-based alloy powder with a particle size range of 10~53μm is obtained by sequentially passing through 120 mesh and 270 mesh screens, and the proportion of this particle size range is controlled to be ≥65%; (4) Inspection and Packaging: The graded powder is tested for oxygen and nitrogen content, sphericity, hollow powder rate, flowability and density. Qualified products are sealed in a vacuum environment to avoid moisture absorption and oxidation during transportation and storage, thus obtaining aluminum-based alloy powder for additive manufacturing. Among them, products that meet the following indicators are qualified: hydrogen content ≤0.10µg / g Al, oxygen content ≤300ppm, nitrogen content ≤200ppm, sphericity ≥95%, satellite powder defect rate ≤0.15‰, hollow powder rate ≤0.23‰, laser particle size d50=25~45μm, 10~53μm particle size ratio ≥65%, Hall flow rate ≤36s / 50g, loose density ≥1.45g / cm³, tapped density ≥2.0g / cm³, powder yield ≥95%.

[0028] This method achieves low-cost and stable production of AlSi10Mg / AlSi12 alloy powder through a complete process of "low-cost and high-purity master alloy preparation - high-efficiency tight-coupled supersonic gas atomization - precise sieving and classification". It innovatively designs a ring-hole type tight-coupled atomizer structure and optimizes the master alloy smelting and atomization process parameters.

[0029] Specifically, the pretreatment of recycled aluminum includes: manual sorting to remove impurities such as iron blocks and plastics, crushing to a particle size of 50~100mm, drying at 200~300℃ for 2~4 hours, and removing surface oil and moisture.

[0030] Ingot surface cleaning includes: grinding and cleaning the surface of the ingot to remove oxide scale and surface defects.

[0031] More specifically, the method for preparing aluminum-based alloy powder for additive manufacturing includes the following steps: (1) Preparation of high-purity homogenized master alloy: Recycled aluminum is used as the main raw material. Impurities such as iron blocks, plastics, and soil are removed by manual sorting. The aluminum is crushed to a particle size of 50-100 mm and dried at 200-300℃ for 2-4 hours to remove surface oil and moisture. The pretreated recycled aluminum and alloying elements (Si, Mg, etc.) are mixed according to the AlSi10Mg or AlSi12 alloy composition ratio and loaded into an electric furnace / gas furnace and heated to 720-780℃ for melting. After the raw materials are completely melted, alloying treatment is carried out. Then, a composite refining agent is added and refined at 720-750℃ for 40-60 minutes. Through the physicochemical reaction between the refining agent and the melt, degassing, slag removal and inclusion modification are achieved. After refining, the slag is removed, and the mixture is allowed to stand for 20-30 minutes to allow any remaining inclusions to float to the surface. A semi-continuous casting process is then used to cast the ingot, with a casting speed of 0.8-1.5 m / min, a cooling water flow rate of 5-8 m³ / h, and an ingot diameter of 150-300 mm. Finally, the ingot is surface-polished to remove oxide scale and surface defects, yielding a highly clean and homogeneous master alloy.

[0032] (2) High-efficiency tight-coupled supersonic gas atomization: The master alloy ingot is placed in an induction melting furnace and vacuumed to ≤1×10 -The solution is heated to 750-900℃ and remelted, then held for 15-25 minutes to ensure homogenization of the composition. The molten master alloy is introduced into a tightly coupled annular atomizer through a graphite liquid guide tube (inner diameter 8-12mm). The coaxiality deviation between the liquid guide tube and the atomizer is ≤0.5mm to avoid liquid flow deviation affecting the atomization effect. The atomizer has an optimized structural design with 12-32 annular holes, an annular hole diameter of 0.3-1.5mm, a spray apex angle of 35-55°, a pitch circle diameter of 55-75mm, and a distance of 8-12mm between the liquid guide tube outlet and the atomizer spray plane, which can significantly improve the airflow velocity and liquid flow breaking efficiency. Argon gas with a purity of ≥99.99% is used as the atomizing gas and preheated to 120~180℃ to reduce the temperature difference between the melt and the gas, avoiding morphological defects caused by rapid powder solidification. The atomization pressure is controlled at 4~7MPa to ensure that the gas outlet velocity reaches supersonic speed, ensuring that the molten metal flow is fully broken into fine droplets. During atomization, the pressure rise rate of the atomizing tank is maintained at ≤0.67Pa / h. The powder is collected by a cyclone separation and collection system, and the powder morphology is monitored in real time using dual-beam detection technology to control the satellite powder defect rate at ≤0.15‰ and the hollow powder rate at ≤0.23‰.

[0033] (3) Precise sieving and grading: The collected atomized powder is transferred to the drying workshop (ambient humidity ≤40%) and graded using a multi-stage vibrating sieving device. First, coarse powder larger than 125μm is removed by passing it through a 120-mesh sieve, and then fine powder smaller than 53μm is removed by passing it through a 270-mesh sieve, to obtain aluminum-based alloy powder with a target particle size range of 10~53μm, ensuring that this particle size range accounts for ≥65%. Inert gas protection is used during the sieving process to avoid the powder absorbing moisture or oxidizing.

[0034] (4) Inspection and Packaging: Comprehensive performance testing is conducted on the graded powder: oxygen and nitrogen content is detected using an oxygen and nitrogen analyzer, sphericity and hollow powder rate are observed using a scanning electron microscope, particle size distribution is tested using a laser particle size analyzer, and flowability, loose packing density, and tapped density are detected using a Hall flow meter and a densitometer. Products meeting the following indicators are considered qualified: oxygen content ≤290ppm, nitrogen content ≤190ppm, sphericity ≥95.5%, 10~53μm particle size percentage ≥65%, Hall flow rate ≤35s / 50g, loose packing density ≥1.48g / cm³, tapped density ≥2.08g / cm³, and powder yield ≥95%. Qualified products are sealed in a vacuum environment to prevent moisture absorption and oxidation during transportation and storage.

[0035] The implementation process of the present invention will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. It should also be noted that, for ease of description, only the parts related to the invention are shown in the embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present application will now be described in detail with reference to the embodiments. It should be noted that the endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0036] In the following examples, all raw materials used are common commercially available products that can be purchased directly or can be prepared using conventional techniques in the field.

[0037] I. Examples of the preparation method of aluminum-based alloy powder for additive manufacturing according to the present invention Example 1 The method for preparing aluminum-based alloy powder for additive manufacturing provided in this embodiment includes the following steps: (1) Preparation of high-purity homogenized master alloy: Recycled aluminum is used as the main raw material. Impurities such as iron blocks, plastics and mud are removed by manual sorting. The material is crushed to a particle size of 50~100mm and dried at 250℃ for 3h to remove surface oil and moisture. The pretreated recycled aluminum is batched according to the AlSi10Mg alloy composition ratio and loaded into a gas furnace and heated to 750℃ for melting. After the raw material is completely melted, alloying treatment is carried out. Then, a composite refining agent (NaCl 35%, Na3AlF6 30%, CaF2 18%, CeO2 7%) is added at a rate of 1.0% of the melt mass. The material is refined at 730℃ for 50min. After refining, the slag is removed and the material is allowed to stand for 25min to allow the remaining inclusions to float. The ingot is cast using a semi-continuous casting process with a casting speed of 1.2m / min, a cooling water flow of 6m³ / h, and an ingot diameter of 200mm. Finally, the ingot was surface-polished to remove oxide scale and surface defects, yielding a highly clean and homogeneous master alloy. The master alloy was found to have a hydrogen content of 0.08 µg / g Al, a slag content of 0.03 mm² / kg, and inclusion sizes ≤45 μm.

[0038] (2) High-efficiency tight-coupled supersonic gas atomization: The master alloy ingot is placed in an induction melting furnace and vacuumed to ≤1×10 -The solution is heated to 750℃ and remelted, then held for 20 minutes to ensure homogenization of the composition. The molten master alloy is introduced into a ring-hole tightly coupled atomizer through a graphite liquid guide tube (8mm inner diameter). Argon gas with a purity ≥99.99% is used as the atomizing gas, preheated to 150℃, and the atomization pressure is controlled at 5MPa. The powder is collected by a cyclone separation and collection system. Simultaneously, dual-beam detection technology is used to monitor the powder morphology in real time, controlling the satellite powder defect rate to 0.15‰ and the hollow powder rate to 0.2‰. The atomizer has 20 ring holes with a diameter of 1mm, a spray apex angle of 45°, a pitch circle diameter of 65mm, and a distance of 10mm between the liquid guide tube outlet and the spray plane of the ring-hole tightly coupled atomizer.

[0039] (3) Precise sieving and grading: The collected atomized powder is transferred to the drying workshop (ambient humidity 35%) and graded using a multi-stage vibrating sieving device. First, coarse powder larger than 125μm is removed by passing it through a 120-mesh sieve, and then fine powder smaller than 53μm is removed by passing it through a 270-mesh sieve. The aluminum-based alloy powder with a target particle size range of 10~53μm is obtained by screening, ensuring that this particle size range accounts for 65%, and inert gas protection is used during the sieving process.

[0040] (4) Packaging Inspection: A comprehensive performance test was conducted on the graded powder: oxygen and nitrogen content was detected using an oxygen and nitrogen analyzer, sphericity was observed using a scanning electron microscope, particle size distribution was tested using a laser particle size analyzer, and flowability, loose packing density, and tapped density were detected using a Hall flow meter and a densitometer. Test results: oxygen content 280ppm, nitrogen content 180ppm, sphericity 96.2%, Hall flow rate 34s / 50g, loose packing density 1.52g / cm³, tapped density 2.15g / cm³, yield 96.5%, meeting the requirements. Vacuum-sealed packaging qualified products were sealed and packaged in a vacuum environment.

[0041] Example 2 The method for preparing aluminum-based alloy powder for additive manufacturing provided in this embodiment includes the following steps: (1) Preparation of high-purity homogenized master alloy: Recycled aluminum is used as the main raw material. Impurities such as iron blocks, plastics and mud are removed by manual sorting. The material is crushed to a particle size of 60~100mm and dried at 280℃ for 2.5h to remove surface oil and moisture. The pretreated recycled aluminum is batched according to the AlSi12 alloy composition ratio and loaded into a gas-fired furnace and heated to 760℃ for melting. After the raw material is completely melted, alloying treatment is carried out. Then, a composite refining agent (NaCl 38%, Na3AlF6 28%, CaF2 16%, CeO2 8%) is added at a rate of 1.1% of the melt mass. The material is refined at 740℃ for 45min. After refining, the slag is removed and the material is allowed to stand for 22min to allow the remaining inclusions to float. The ingot is cast using a semi-continuous casting process with a casting speed of 1.0m / min, a cooling water flow of 7m³ / h, and an ingot diameter of 250mm. Finally, the ingot was surface-polished to remove oxide scale and surface defects, yielding a highly clean and homogeneous master alloy. The master alloy was found to have a hydrogen content of 0.09 µg / g Al, a slag content of 0.035 mm² / kg, and inclusion sizes ≤25 μm.

[0042] (2) High-efficiency tight-coupled supersonic gas atomization: The master alloy ingot is placed in an induction melting furnace and vacuumed to 1×10 - Below 3Pa, the material is heated to 880℃ and remelted, then held for 18 minutes to ensure homogenization of the composition. The molten master alloy is introduced into a ring-hole tightly coupled atomizer through a graphite liquid guide tube (12mm inner diameter). Argon gas with a purity ≥99.99% is used as the atomizing gas, preheated to 160℃, and the atomization pressure is controlled at 6MPa. The powder is collected by a cyclone separation and collection system. Simultaneously, dual-beam detection technology is used to monitor the powder morphology in real time, controlling the satellite powder defect rate to 0.15‰ and the hollow powder rate to 0.15‰. The atomizer has 30 ring holes with a diameter of 0.5mm, a spray apex angle of 50°, a pitch circle diameter of 70mm, and a distance of 9mm between the liquid guide tube outlet and the spray plane of the ring-hole tightly coupled atomizer.

[0043] (3) Precise sieving and grading: The collected atomized powder is transferred to the drying workshop (ambient humidity 38%) and graded using a multi-stage vibrating sieving device. First, coarse powder larger than 125μm is removed by passing it through a 120-mesh sieve, and then fine powder smaller than 53μm is removed by passing it through a 270-mesh sieve. The aluminum-based alloy powder with a target particle size range of 10~53μm is obtained by screening, ensuring that this particle size range accounts for 66%, and inert gas protection is used during the sieving process.

[0044] (4) Packaging Inspection: A comprehensive performance test was conducted on the graded powder: oxygen and nitrogen content was detected using an oxygen and nitrogen analyzer, sphericity was observed using a scanning electron microscope, particle size distribution was tested using a laser particle size analyzer, and flowability, loose packing density, and tapped density were detected using a Hall flow meter and a densitometer. Test results: oxygen content 290ppm, nitrogen content 190ppm, sphericity 95.5%, Hall flow rate 35s / 50g, loose packing density 1.48g / cm³, tapped density 2.08g / cm³, yield 95.8%, meeting the requirements. Vacuum-sealed packaging qualified products were sealed and packaged in a vacuum environment.

[0045] This demonstrates that the aluminum-based alloy powder for additive manufacturing prepared by the method of the present invention has an oxygen content ≤290ppm, a nitrogen content ≤190ppm, a sphericity ≥95.5%, a particle size ratio of 10~53μm ≥65%, a Hall flow rate ≤35s / 50g, a loose packing density ≥1.48g / cm³, a tap density ≥2.08g / cm³, and a powder yield ≥95.8%. It reduces production costs by more than 30% and is suitable for additive manufacturing of large and complex components in aerospace, automotive, and transportation fields, possessing significant technological innovation and industrialization value.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A method for preparing aluminum-based alloy powder for additive manufacturing, characterized in that, Includes the following steps: Step 1: Using recycled aluminum as raw material, after pretreatment, batching, electric furnace / gas furnace smelting, alloying treatment, compound refining agent is added for refining, and then after slag removal, static refining and semi-continuous casting, a master alloy with hydrogen content ≤0.09µg / g Al and inclusion content ≤0.035mm² / kg is obtained. Step 2: Place the master alloy in an induction melting furnace for induction remelting to obtain a molten master alloy; Step 3: After the molten master alloy is introduced into the annular tightly coupled atomizer through the liquid guide tube for supersonic vacuum atomization, it is then sieved and classified to obtain aluminum-based alloy powder.

2. The method for preparing aluminum-based alloy powder for additive manufacturing according to claim 1, characterized in that, The ingredients are: The pretreated recycled aluminum and alloying elements are mixed according to the AlSi10Mg or AlSi12 alloy composition ratio.

3. The method for preparing aluminum-based alloy powder for additive manufacturing according to claim 1, characterized in that, The melting temperature is 720~780℃; the refining temperature is 720~750℃ and the time is 40~60min; the standing refining time is 20~30min.

4. The method for preparing aluminum-based alloy powder for additive manufacturing according to claim 1, characterized in that, The composite refining agent is composed of the following components by mass percentage: NaCl 30~40%, Na3AlF6 25~35%, CaF2 15~20%, CeO2 3~8%; the amount of the composite refining agent added is 0.8~1.2% of the mass of the melt after smelting.

5. The method for preparing aluminum-based alloy powder for additive manufacturing according to claim 1, characterized in that, The parameters for the semi-continuous casting are: casting speed 0.8~1.5m / min, cooling water volume 5~8m³ / h; and the diameter of the master alloy is 150~300mm.

6. The method for preparing aluminum-based alloy powder for additive manufacturing according to claim 1, characterized in that, The induction remelting temperature is 750~900℃, and the time is 15~25 min; the induction remelting is carried out under a vacuum degree ≤1×10 - The test was conducted under conditions of ³Pa.

7. The method for preparing aluminum-based alloy powder for additive manufacturing according to claim 1, characterized in that, During the supersonic vacuum atomization process, dual-beam detection technology is used to monitor the powder morphology in real time, controlling the satellite powder defect rate to be ≤0.15‰ and the hollow powder rate to be ≤0.23‰.

8. The method for preparing aluminum-based alloy powder for additive manufacturing according to claim 1, characterized in that, The number of annular holes in the tightly coupled atomizer is 12-32, the spray apex angle is 35-55°, and the ratio of the annular hole diameter to the pitch circle diameter is (0.3-1.5):(55-75). The liquid guide tube is made of graphite, and the ratio of the inner diameter of the liquid guide tube to the annular hole diameter is (8-12):(0.3-1.5). The distance between the outlet of the liquid guide tube and the spray plane of the tightly coupled atomizer is 8-12 mm, and the coaxiality deviation between the liquid guide tube and the tightly coupled atomizer is ≤0.5 mm.

9. The method for preparing aluminum-based alloy powder for additive manufacturing according to claim 1, characterized in that, The sieving and grading is carried out under an ambient humidity of ≤40% to obtain aluminum-based alloy powder with a particle size range of 10-53μm, such that the proportion of aluminum-based alloy powder in this particle size range is ≥65%.

10. An aluminum-based alloy powder for additive manufacturing, characterized in that, It is prepared by the method for preparing aluminum-based alloy powder for additive manufacturing as described in any one of claims 1 to 9; the performance indicators of the qualified product of the aluminum-based alloy powder for additive manufacturing are: oxygen content ≤ 290 ppm, nitrogen content ≤ 190 ppm, sphericity ≥ 95.5%, Hall flow rate ≤ 35 s / 50 g, loose packing density ≥ 1.48 g / cm³, tap density ≥ 2.08 g / cm³; the yield of the qualified product is ≥ 95.8%.