High-strength anti-cracking Al-Mn-Sc alloy powder, preparation method thereof and application of high-strength anti-cracking Al-Mn-Sc alloy powder in additive manufacturing

Abstract

The invention discloses high-strength anti-cracking Al-Mn-Sc alloy powder, a preparation method of the high-strength anti-cracking Al-Mn-Sc alloy powder and application of the high-strength anti-cracking Al-Mn-Sc alloy powder in additive manufacturing, and belongs to the technical field of additive manufacturing. The alloy powder comprises the following components in percentage by mass: 1.5 to 3 weight percent of Mn, 1 to 5 weight percent of Mg, 0.7 to 0.9 weight percent of Sc, 0.2 to 0.5 weight percent of Zr, 0.01 to 2 weight percent of X element and the balance of Al. The alloy powder is excellent in laser 3D printing formability, free of macroscopic and microcosmic cracks after 3D printing and high in density; after one-step aging heat treatment, the yield strength can reach 530 MPa or above, the ductility can reach 14% or above, the room-temperature fatigue strength can reach 250 MPa, and the high-toughness and fatigue-resistant characteristics are achieved; the yield strength at 250 DEG C can reach 530 MPa or above, the ductility can reach 14% or above, and the alloy is suitable for additive manufacturing and powder metallurgy of light-weight high-performance parts.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, and in particular to a high-strength, crack-resistant Al-Mn-Sc alloy powder, its preparation method, and its application in additive manufacturing. Background Technology

[0002] Aluminum alloys are widely used in various industrial fields due to their lightweight and high specific strength. With the rapid development of additive manufacturing (3D printing) technology, the manufacturing methods of aluminum alloys have undergone significant innovation. Processes such as laser bed fusion (LPBF) achieve the freeform shaping of complex components by melting metal powder layer by layer, greatly improving design freedom and material utilization, and allowing for optimization of microstructure by controlling process parameters. Furthermore, other additive technologies such as directed energy deposition (DED) provide new solutions for large-scale manufacturing, parts repair, and gradient material preparation.

[0003] In the aerospace field, components such as engines and combustion chambers need to operate at temperatures of 300-400°C for extended periods while meeting stringent lightweight requirements. However, most commercially available aluminum alloys lack sufficient high-temperature strength, while titanium alloys are expensive and can increase the weight of structural components by 25%-40%, diminishing the advantages of lightweight design. Therefore, developing a dedicated heat-resistant, high-strength aluminum alloy suitable for additive manufacturing and capable of maintaining a tensile strength of over 300 MPa over a wide working window has become an ideal lightweight solution.

[0004] To address this, researchers have developed aluminum alloys based on the Al-Mg-Sc system. These alloys primarily achieve strengthening through the precipitation of thermally stable Al3Sc nano-precipitates, exhibiting high thermal stability and maintaining strength and creep resistance at high temperatures. However, the strengthening of this system mainly relies on Mg, and there is still room for improvement in absolute strength. Furthermore, Al-Mg-Sc alloys still face a series of technical bottlenecks in practical applications: excessively high Mg content can lead to smoke generation during printing, contaminating equipment and affecting corrosion resistance; excessively high Mn content may cause macroscopic cracking; and excessively high Sc content can impair plasticity and significantly increase costs. These factors collectively limit their application in high-performance scenarios.

[0005] Therefore, there is an urgent need to develop a new type of Al-Mn-Sc alloy, which can overcome the problem of difficulty in achieving strength, heat resistance and printability in the existing alloy system by reasonably adjusting the composition of Mn, Mg and Sc elements. Summary of the Invention

[0006] The purpose of this invention is to provide a high-strength, crack-resistant Al-Mn-Sc alloy powder, its preparation method, and its application in additive manufacturing. By rationally allocating the content of solid solution elements and precipitation strengthening elements in the aluminum alloy, and combining it with a specific 3D printing post-heat treatment scheme, the high-strength aluminum alloy can be prepared.

[0007] To achieve the above objectives, the present invention provides a high-strength, crack-resistant Al-Mn-Sc alloy powder, comprising the following components by mass percentage: 1.5-3wt% Mn, 1-5wt% Mg, 0.7-0.9wt% Sc, 0.2-0.5wt% Zr, 0.01-2wt% X element, with the balance being Al and unavoidable impurity elements, wherein the unavoidable impurity elements are ≤0.2wt%.

[0008] Preferably, element X is a strengthening element, selected from one or more of La, Ce, Y, Nd, Ti, Er, Ni, Gd, Cr, Dy and Yb.

[0009] The present invention also provides a method for preparing the above-mentioned high-strength crack-resistant Al-Mn-Sc alloy powder, wherein the Al-Mn-Sc alloy powder is prepared by melting aluminum, magnesium, manganese, zirconium, aluminum-scandium alloy and aluminum-based master alloy or X metal containing element X, and then using any one of the following preparation methods: gas atomization, ultrasonic atomization, or wire powdering.

[0010] Preferably, the smelting method involves placing the raw materials into a smelting furnace, subjecting them to vacuum treatment, then introducing argon gas to atmospheric pressure for protection, and heating the smelting furnace to melt the raw materials.

[0011] Preferably, the vacuum degree is within 200Pa, the typical melting temperature is 800-900℃, and the holding time is 20-40min.

[0012] The high-strength, crack-resistant Al-Mn-Sc alloy powder provided by this invention is applied in additive manufacturing.

[0013] Preferably, it includes the following steps: (1) Pretreatment of Al-Mn-Sc alloy powder; (2) The Al-Mn-Sc alloy powder is subjected to laser powder bed melting (LPBF), electron beam powder bed melting (EB-PBF), directed energy deposition (DED), binder spraying (BJ), and selective laser sintering (SLS). Metal Injection Molding ( MIM 3D printing and powder metallurgy forming can be performed using any of the following processes; (3) Heat treatment: Heat the printed sample in step (2) to 275-325℃ and keep it warm for 1-12 hours; after the heat treatment is completed, cool it rapidly at a rate of ≥10℃ / min.

[0014] Preferably, the Al-Mn-Sc alloy powder has a particle size of 15-150 μm and a sphericity > 0.85.

[0015] Preferably, in step (1), the pretreatment method is: vacuum drying of Al-Mn-Sc alloy powder, with a typical drying temperature of 130-150℃ and a time of 8-24h.

[0016] Preferably, the printed sample after step (3) has a yield strength ≥530MPa, a tensile strength ≥540MPa, and an elongation ≥15% at room temperature.

[0017] Therefore, the present invention, employing the above-mentioned high-strength, crack-resistant Al-Mn-Sc alloy powder, its preparation method, and its application in additive manufacturing, possesses the following beneficial effects: (1) This invention utilizes the high cooling rate and solute retention characteristics of 3D printing technology to rationally control the elemental content of solid solution elements Mn and Mg in aluminum alloys, thereby obtaining supersaturated solid solution elements while inhibiting the formation of excessive Al-Mn intermetallic compounds and avoiding the generation of macroscopic and microscopic cracks. After heat treatment, a large number of fine and thermally stable Al3(Sc,Zr) nanophases are precipitated from the supersaturated solid solution, achieving a significant precipitation strengthening effect and thus obtaining excellent room temperature strength and toughness matching.

[0018] (2) By adding an appropriate amount of X element, the microstructure and phase stability of the alloy were further optimized, so that the aluminum alloy has high high temperature strength and can maintain high strength in a wide temperature range, which significantly improves the heat resistance and high temperature service capability of the alloy.

[0019] (3) The alloy powder laser 3D printing of the present invention has excellent formability, no macro and micro cracks after 3D printing, and high density; after one-step aging heat treatment, the yield strength can reach more than 530 MPa, the elongation can reach more than 14%, and the room temperature fatigue strength can reach 250 MPa, which has high strength, toughness and fatigue resistance; the yield strength at 250℃ can reach more than 530 MPa and the elongation can reach more than 14%, which is suitable for additive manufacturing and powder metallurgy of lightweight high-performance parts in aerospace, energy and chemical industry, low-altitude economy, automotive industry, etc., especially suitable for integrated manufacturing of high-temperature service parts such as engines, combustion chambers, heat exchangers, etc.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 SEM image of the Al-Mn-Sc alloy powder prepared in Example 1; Figure 2Metallographic images of the printed sample prepared for Example 1; Figure 3 A photograph of the printed sample prepared in Example 1; Figure 4 The engineering stress-strain curves of the printed and aged samples prepared in Example 1 are shown. Figure 5 The stress-strain curves of the samples prepared in Examples 1, 2 and 3 under aging conditions are shown. Figure 6 Physical photographs of the printed samples prepared for comparison; Figure 7 The stress-strain curves of the aged samples prepared for comparison are shown. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0024] This invention addresses the problems of hot cracking tendency and insufficient high-temperature performance in additively manufactured aluminum alloys through precise element synergistic design: by controlling the Mn content, it provides strengthening and inhibits the formation of coarse and brittle Al-Mn phases, thereby avoiding cracking; an appropriate amount of Mg is added for auxiliary solid solution strengthening; at the same time, X elements such as Sc, Zr and specific rare earth elements are introduced to form thermally stable nano-precipitates Al3(Sc,Zr) or to play a grain boundary strengthening role, thereby significantly improving the room temperature toughness, high temperature strength and stability of the alloy.

[0025] This high-strength, crack-resistant Al-Mn-Sc alloy powder contains the following components by mass percentage: 1.5-3 wt% Mn, 1-5 wt% Mg, 0.7-0.9 wt% Sc, 0.2-0.5 wt% Zr, 0.01-2 wt% X element, with the balance being Al and unavoidable impurity elements, with unavoidable impurity elements ≤0.2 wt%. X element is a strengthening element selected from one or more of La, Ce, Y, Nd, Ti, Er, Ni, Gd, Cr, Dy, and Yb.

[0026] This invention provides an aluminum alloy suitable for additive manufacturing, the preparation and implementation methods of which are as follows: Step 1: Alloy smelting and base material preparation Weigh the raw materials according to the designed proportions, including pure aluminum, pure magnesium, aluminum-manganese master alloy, aluminum-scandium master alloy, and other master alloys or metals containing X elements (La, Ce, Y, Nd, Ti, Er, Ni, Gd, Cr, Dy, and Yb). Place the raw materials in a vacuum induction melting furnace, evacuate to below 200 Pa, and then purge with high-purity argon to atmospheric pressure as a protective atmosphere. Heat to 800-900℃ to completely melt the furnace charge and hold at that temperature for 30-40 minutes, during which time electromagnetic stirring is performed to ensure sufficient diffusion and uniform distribution of alloying elements. Then, cast the melt into a uniformly composed aluminum alloy masterbatch ingot.

[0027] Step 2: Prepare Al-Mn-Sc alloy powder using any one of the following methods: gas atomization, ultrasonic atomization, or wire powder preparation.

[0028] Preferably, to obtain spherical powder with highly uniform elemental distribution, a stepwise gas atomization process is adopted: The aforementioned aluminum alloy base material ingot is placed in the vacuum melting chamber of a gas atomization device and reheated for melting. Under argon protection, the melt temperature is stabilized within the range of 900-950℃ and held for 20-30 minutes. This process promotes secondary and thorough diffusion of alloying elements such as Mn, Sc, and Zr, resulting in a more uniform distribution within the aluminum matrix, eliminating micro-segregation, and achieving macro- and micro-uniformity of the melt composition. After holding, the highly homogeneous melt is introduced into an atomizing nozzle and prepared into spherical powder using high-pressure inert gas.

[0029] Step 3: Additive Manufacturing and Heat Treatment Al-Mn-Sc alloy powder is pretreated by vacuum drying at 130-150℃ for 8-24 hours. The powder is then 3D printed using any of the following methods: microprinting, DED (Dual Engraving), or powder-spreading printing.

[0030] Preferably, the obtained alloy powder is used for laser powder bed melting (LPBF) forming. Preferred process parameters are: laser power 300-375W, scanning speed 1000-1600 mm / s, scanning spacing 0.10-0.12 mm, and powder layer thickness 0.03-0.05 mm. This combination of parameters, synergistically with the alloy composition, allows elements such as Mn and Mg to dissolve in the aluminum matrix, effectively suppressing the in-situ formation of coarse Al-Mn intermetallic compounds, thereby avoiding hot cracking. The formed parts are then heat-treated at 275-325℃ to promote the uniform precipitation of nano-scale Al3(Sc,Zr) strengthening phases, resulting in components with excellent room temperature and high temperature mechanical properties.

[0031] To adapt this solution to other 3D printing processes, the powder particle size and energy parameters can be adjusted accordingly, while the core mechanism of suppressing cracking and achieving reinforcement remains unchanged.

[0032] The printed samples were heated to 275-325℃ and held for 1-12 hours. After the holding time, they were rapidly cooled at a rate of 100-200℃ / min.

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following description will be provided in conjunction with the accompanying drawings of the embodiments of the present invention. Figures 1 to 7 The technical solutions of the present invention have been clearly and completely described. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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] Example 1 This embodiment provides a method for applying high-strength, crack-resistant Al-Mn-Sc alloy powder in 3D printing. The composition and mass percentage of the Al-Mn-Sc alloy powder are: Mn: 2.0%, Mg: 3.0%, Sc: 0.75%, Zr: 0.3%, Ti: 0.05%, with the balance being Al. The application method includes the following steps: (1) Alloy smelting: Based on the content of raw materials in the above aluminum alloy powder, weigh the corresponding mass of pure aluminum, pure magnesium, pure manganese, pure zirconium, pure titanium, and aluminum-scandium alloy, and place them in a smelting furnace. Evacuate the smelting furnace to a vacuum degree below 200 Pa, and then fill it with argon gas to make the pressure inside the smelting furnace reach atmospheric pressure. Heat the smelting furnace to 800℃ to completely melt the raw materials into liquid, and then hold it at that temperature for 30 min. Then, pour the alloy melt into an ingot in the vacuum chamber, and remove the ingot after 5 min for air cooling.

[0035] (2) Powder atomization: The master alloy ingot is placed in the crucible of the atomization equipment and heated to 900℃. After the alloy is completely melted, it is held at that temperature for 20 minutes. Then, the molten alloy is guided into the falling channel and blown into fine droplets by a high-speed argon atomizer. After solidification, it forms spherical alloy powder. The original powder is then sieved using a vibrating screen to obtain powder that meets the requirements of 3D printing. The SEM image of the powder is shown below. Figure 1 As shown, the vast majority of particles are spherical or nearly spherical, with a particle size of 15-65 micrometers.

[0036] (3) Preparation of Al-M-Sc alloy components: The sieved aluminum alloy powder was vacuum dried at a temperature of 140℃ for 24 hours. The dried aluminum alloy powder was then printed using a laser powder bed fusion device with a laser power of 375W, a scanning speed of 1200mm / s, a scanning distance of 0.1mm, and a powder layer thickness of 0.03mm.

[0037] (4) Heat treatment of Al-Mn-Sc alloy components: The printed parts are 65 (length) × 12 (width) × 65 (height) mm in size. The printed samples are heat-treated at 300℃ for 7 hours, and then rapidly cooled to room temperature at a rate of 100℃ / min. Metallographic photographs of the alloy are shown below. Figure 2 As shown, the sample has only a very small number of submicron-sized pores, with a density as high as 99.9%. The alloy photograph is shown below. Figure 3 As shown.

[0038] Example 2: This embodiment provides a method for applying high-strength, crack-resistant Al-Mn-Sc alloy powder in 3D printing. The composition and mass percentage of the Al-Mn-Sc alloy powder are: Mn: 2.5%, Mg: 2.5%, Sc: 0.75%, Zr: 0.3%, Cr: 1%, Ni: 0.01%, with the balance being Al. The application method includes the following steps: (1) Alloy smelting: Based on the content of the above raw materials, weigh out the corresponding masses of pure aluminum, pure magnesium, pure manganese, pure zirconium, pure nickel, aluminum-scandium alloy, and aluminum-chromium alloy, and place them in a smelting furnace. Evacuate the smelting furnace to a vacuum degree of 200 Pa, and then fill it with argon gas to bring the pressure inside the smelting furnace to atmospheric pressure. Heat the smelting furnace to 800°C to completely melt the raw materials into a liquid, and then hold it at that temperature for 30 minutes. Then, pour the alloy melt into an ingot in the vacuum chamber, and remove the ingot after 5 minutes for air cooling.

[0039] (2) Powder atomization: The master alloy ingot is placed in the crucible of the atomization equipment and heated to 900°C. After the alloy is completely melted, it is kept at this temperature for 20 minutes. Then, the molten alloy is guided into the falling channel and blown into fine droplets by a high-speed argon atomizer. After solidification, it forms spherical alloy powder. The original powder is then sieved using a vibrating screen to obtain powder that meets the requirements of 3D printing.

[0040] (3) Preparation of Al-Mn-Sc alloy components: The sieved aluminum alloy powder was vacuum dried at a temperature of 140℃ for 24 hours. The dried aluminum alloy powder was then printed using a laser powder bed fusion device with a laser power of 375W, a scanning speed of 1200mm / s, a scanning distance of 0.1mm, and a powder layer thickness of 0.03mm.

[0041] (4) Heat treatment of Al-Mn-Sc alloy components: The printed sample was heat treated at a temperature of 300℃ for 4 hours and then rapidly cooled at a rate of 150℃ / min.

[0042] Example 3: This embodiment provides a method for applying high-strength, crack-resistant Al-Mn-Sc alloy powder in 3D printing. The composition and mass percentage of the Al-Mn-Sc alloy powder are: Mn: 2.0%, Mg: 3.0%, Sc: 0.75%, Zr: 0.3%, Y: 0.4%, with the balance being Al. The application method includes the following steps: (1) Alloy smelting: Based on the content of the above raw materials, weigh the corresponding masses of pure aluminum, pure magnesium, pure manganese, pure zirconium, aluminum-scandium alloy, and aluminum-yttrium alloy, and place them in a smelting furnace. Evacuate the smelting furnace to a vacuum degree of less than 200 Pa, and then fill it with argon gas to bring the pressure inside the smelting furnace to atmospheric pressure. Heat the smelting furnace to 800°C to completely melt the raw materials into a liquid, and then hold it at that temperature for 30 minutes. Then, pour the alloy melt into an ingot in the vacuum chamber, and remove the ingot after 5 minutes for air cooling.

[0043] (2) Powder atomization: The master alloy ingot is placed in the crucible of the atomization equipment and heated to 900°C. After the alloy is completely melted, it is kept at this temperature for 20 minutes. Then, the molten alloy is guided into the falling channel and blown into fine droplets by a high-speed argon atomizer. After solidification, it forms spherical alloy powder. The original powder is then sieved using a vibrating screen to obtain powder that meets the requirements of 3D printing.

[0044] (3) Preparation of Al-Mn-Sc alloy components: The sieved aluminum alloy powder was vacuum dried at a temperature of 140℃ for 24 hours. The dried aluminum alloy powder was then printed using a laser powder bed fusion device with a laser power of 325W, a scanning speed of 1000mm / s, a scanning distance of 0.1mm, and a powder layer thickness of 0.03mm.

[0045] (4) Heat treatment of Al-Mn-Sc alloy components: The printed sample was heat treated at a temperature of 300℃ for 5 hours. After the heat treatment, it was rapidly cooled to room temperature at a rate of 150℃ / min.

[0046] Example 4 This embodiment provides a method for applying high-strength, crack-resistant Al-Mn-Sc alloy powder in 3D printing. The composition and mass percentage of the Al-Mn-Sc alloy powder are: Mn: 2.0%, Mg: 3.0%, Sc: 0.75%, Zr: 0.3%, Ti: 0.8%, with the balance being Al. The application method includes the following steps: (1) Alloy smelting: Based on the content of the above raw materials, weigh out the corresponding masses of pure aluminum, pure magnesium, pure manganese, pure zirconium, aluminum-scandium alloy, and pure titanium, and place them in a smelting furnace. Evacuate the smelting furnace to a vacuum degree of 200 Pa, and then fill it with argon gas to bring the pressure inside the smelting furnace to atmospheric pressure. Heat the smelting furnace to 800°C to completely melt the raw materials into a liquid, and then hold it at that temperature for 30 minutes. Then, pour the alloy melt into an ingot in the vacuum chamber, and remove the ingot after 5 minutes for air cooling.

[0047] (2) Powder atomization: The master alloy ingot is placed in the crucible of the atomization equipment and heated to 900°C. After the alloy is completely melted, it is kept at this temperature for 20 minutes. Then, the molten alloy is guided into the falling channel and blown into fine droplets by a high-speed argon atomizer. After solidification, it forms spherical alloy powder. The original powder is then sieved using a vibrating screen to obtain powder that meets the requirements of 3D printing.

[0048] (3) Preparation of Al-Mn-Sc alloy components: The sieved aluminum alloy powder was vacuum dried at a temperature of 140℃ for 24 hours. The dried aluminum alloy powder was then printed using a laser powder bed fusion device with a laser power of 375W, a scanning speed of 1400mm / s, a scanning distance of 0.1mm, and a powder layer thickness of 0.03mm.

[0049] (4) Heat treatment of Al-Mn-Sc alloy components: The printed sample was heat treated at a temperature of 325℃ for 7 hours. After the heat treatment, it was rapidly cooled to room temperature at a rate of 150℃ / min.

[0050] Example 5 This embodiment provides a method for applying high-strength, crack-resistant Al-Mn-Sc alloy powder in 3D printing. The composition and mass percentage of the Al-Mn-Sc alloy powder are: Mn: 2.0%, Mg: 3.0%, Sc: 0.75%, Zr: 0.3%, Ni: 0.9%, with the balance being Al. The application method includes the following steps: (1) Alloy smelting: Based on the content of the above raw materials, weigh out the corresponding masses of pure aluminum, pure magnesium, pure manganese, pure zirconium, aluminum-scandium alloy, and pure nickel, and place them in a smelting furnace. Evacuate the smelting furnace to a vacuum degree of 200 Pa, and then fill it with argon gas to bring the pressure inside the smelting furnace to atmospheric pressure. Heat the smelting furnace to 800°C to completely melt the raw materials into a liquid, and then hold it at that temperature for 30 minutes. Then, pour the alloy melt into an ingot in the vacuum chamber, and remove the ingot after 5 minutes for air cooling.

[0051] (2) Powder atomization: The master alloy ingot is placed in the crucible of the atomization equipment and heated to 900°C. After the alloy is completely melted, it is kept at this temperature for 20 minutes. Then, the molten alloy is guided into the falling channel and blown into fine droplets by a high-speed argon atomizer. After solidification, it forms spherical alloy powder. The original powder is then sieved using a vibrating screen to obtain powder that meets the requirements of 3D printing.

[0052] (3) Preparation of Al-Mn-Sc alloy components: The sieved aluminum alloy powder was vacuum dried at a temperature of 140℃ for 24 hours. The dried aluminum alloy powder was then printed using a laser powder bed fusion device with a laser power of 350W, a scanning speed of 1200mm / s, a scanning distance of 0.1mm, and a powder layer thickness of 0.03mm.

[0053] (4) Heat treatment of Al-Mn-Sc alloy components: The printed sample was heat treated at a temperature of 325℃ for 5 hours. After the heat treatment, it was rapidly cooled to room temperature at a rate of 150℃ / min.

[0054] Comparative Example This embodiment provides a method for applying high-strength, crack-resistant Al-Mn-Sc alloy powder in 3D printing. The composition and mass percentage of the Al-Mn-Sc alloy powder are: Mn: 5.0%, Mg: 3.0%, Sc: 0.75%, Zr: 0.3%, with the balance being Al. The application method includes the following steps: (1) Alloy smelting: Based on the content of raw materials in the above aluminum alloy powder, weigh the corresponding mass of pure aluminum, pure magnesium, pure manganese, pure zirconium, and aluminum-scandium alloy, and place them in a smelting furnace. Evacuate the smelting furnace to a vacuum degree below 200 Pa, and then fill it with argon gas to bring the pressure inside the smelting furnace to atmospheric pressure. Heat the smelting furnace to 800°C to completely melt the raw materials into a liquid, and then hold it at that temperature for 30 minutes. Then, pour the alloy melt into an ingot in the vacuum chamber, and remove the ingot after 5 minutes for air cooling.

[0055] (2) Powder atomization: The master alloy ingot is placed in the crucible of the atomization equipment and heated to 900℃. After the alloy is completely melted, it is held at that temperature for 20 minutes. Then, the molten alloy is guided into the falling channel and blown into fine droplets by a high-speed argon atomizer. After solidification, it forms spherical alloy powder. The original powder is then sieved using a vibrating screen to obtain powder that meets the requirements of 3D printing. The SEM image of the powder is shown below. Figure 1 As shown, the vast majority of particles are spherical or nearly spherical, with a particle size of 15-65 micrometers.

[0056] (3) Preparation of Al-M-Sc alloy components: The sieved aluminum alloy powder was vacuum dried at a temperature of 140℃ for 24 hours. The dried aluminum alloy powder was then printed using a laser powder bed fusion device with a laser power of 375W, a scanning speed of 1200mm / s, a scanning distance of 0.1mm, and a powder layer thickness of 0.03mm.

[0057] (4) Heat treatment of Al-Mn-Sc alloy components: The printed parts are 65 (length) × 12 (width) × 65 (height) mm in size. The printed samples are heat treated at 300℃ for 7 hours, and then rapidly cooled to room temperature at a rate of 100-200℃ / min. The alloy samples have only a very small number of submicron-sized pores and a density of up to 99.9%.

[0058] The Al-Mn-Sc alloy powder prepared in Example 3 above was tested, and its physical properties are shown in Table 1: Table 1 Physical properties of Al-Mn-Sc alloy powder

[0059] The results show that the prepared powder has good flowability and a relatively uniform particle size distribution, which meets the requirements of 3D printing powder.

[0060] Tensile tests and density measurements were performed on the printed samples prepared in Examples 1-3, and their engineering stress-strain curves are shown below. Figure 5 As shown, Figure 5 The results are summarized in Table 2: Table 2 Tensile test results of printed samples from Examples 1-3

[0061] The results show that the additively manufactured samples in this invention exhibit high density, high room temperature strength (yield strength: ~540MPa) and high plasticity (elongation: ~16%). In addition, their high-temperature tensile properties at 250℃ are also excellent. The sample in Example 3 has a tensile strength of up to 270MPa and an elongation of up to 16.9% at 250℃.

[0062] The axial fatigue performance test results of the printed samples prepared in Example 3 are shown in Table 3: Table 3 Fatigue performance of the printed samples in Example 3

[0063] In this table, the horizontal direction refers to the direction perpendicular to the sample construction (i.e., 65mm × 12mm).

[0064] The results show that the fatigue limit of the sample can reach 250 MPa, demonstrating outstanding fatigue performance.

[0065] Tensile tests were performed on the printed samples prepared in Example 3 and the comparative example, and their engineering stress-strain curves are shown below. Figure 4 and 7 As shown, the results are summarized in Table 3: Table 3. Results of room temperature tensile tests on printed samples from Example 3 and the comparative example.

[0066] In this table, the horizontal direction is perpendicular to the additive manufacturing process, and the vertical direction is the additive manufacturing process direction.

[0067] The results show that the embodiments of the present invention exhibit good formability and no cracking. Figure 3 It also exhibits good room temperature tensile properties, with a yield strength exceeding 530 MPa and an elongation exceeding 14% in the heat-treated state; while the comparative sample showed poor formability and obvious printing cracks. Figure 6 The sample exhibited extremely poor plasticity.

[0068] Therefore, the present invention provides a high-strength, crack-resistant Al-Mn-Sc alloy powder, its preparation method, and its application in additive manufacturing. It is low-cost, has good formability, high toughness, hardenability, and hardenability. At the same time, rare earth elements are used to purify, modify, and alloy it to achieve a long service life of the liner.

[0069] 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 preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-strength, crack-resistant Al-Mn-Sc alloy powder, characterized in that, It contains the following components by mass percentage: 1.5-3 wt% Mn, 1-5 wt% Mg, 0.7-0.9 wt% Sc, 0.2-0.5 wt% Zr, 0.01-2 wt% element X, and the balance is Al.

2. The high-strength, crack-resistant Al-Mn-Sc alloy powder according to claim 1, characterized in that, Element X is a strengthening element, selected from one or more of La, Ce, Y, Nd, Ti, Er, Ni, Gd, Cr, Dy, and Yb.

3. A method for preparing high-strength, crack-resistant Al-Mn-Sc alloy powder as described in any one of claims 1-2, characterized in that, The Al-Mn-Sc alloy powder is prepared by melting aluminum, magnesium, manganese, zirconium, aluminum-scandium alloy and aluminum-based master alloy or X metal containing element X, and then using any one of the following methods: gas atomization, ultrasonic atomization, or wire powder preparation.

4. The method for preparing a high-strength, crack-resistant Al-Mn-Sc alloy powder according to claim 3, characterized in that, The smelting method involves placing the raw materials into a smelting furnace, vacuuming them, and then introducing argon gas to atmospheric pressure for protection before heating the furnace to melt the raw materials.

5. The method for preparing a high-strength, crack-resistant Al-Mn-Sc alloy powder according to claim 4, characterized in that, The vacuum degree is within 200Pa, the typical melting temperature is 800-900℃, and the holding time is 20-40min.

6. The application of the high-strength, crack-resistant Al-Mn-Sc alloy powder as described in any one of claims 1-2, characterized in that, Al-Mn-Sc alloy powder is used in additive manufacturing.

7. The application of the high-strength, crack-resistant Al-Mn-Sc alloy powder according to claim 6, characterized in that, Includes the following steps: (1) Pretreatment of Al-Mn-Sc alloy powder; (2) Al-Mn-Sc alloy powder is printed into shape by additive manufacturing; (3) Heat treatment: Heat the printed sample in step (2) to 275-325℃ and keep it warm for 1-12 hours; after the heat treatment is completed, cool it rapidly at a rate of ≥20℃ / min.

8. The application of the high-strength, crack-resistant Al-Mn-Sc alloy powder according to claim 7, characterized in that, The Al-Mn-Sc alloy powder has a spherical powder particle size of 15-150 μm and a sphericity >0.

85.

9. The application of the high-strength, crack-resistant Al-Mn-Sc alloy powder according to claim 7, characterized in that, In step (1), the pretreatment method is: vacuum drying of Al-Mn-Sc alloy powder, with a typical drying temperature of 130-150℃ and a time of 8-24h.

10. The application of the high-strength, crack-resistant Al-Mn-Sc alloy powder according to claim 7, characterized in that, After step (3), the printed sample has a yield strength ≥530MPa, tensile strength ≥540MPa, and elongation ≥15% at room temperature.

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