Laser powder bed fused heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy and method and application thereof

Abstract

The invention discloses a laser powder bed molten heterogeneous multi-phase nanoparticle synergistically-reinforced aluminum-based alloy and a method and application thereof. The laser powder bed molten heterogeneous multi-phase nanoparticle synergistically-reinforced aluminum-based alloy is composed of equiaxial nanoscale alpha-Al crystal grains. Nano hard phase particles are dispersed and distributed at the grain boundary of the equiaxed nanoscale alpha-Al grains, nanoscale Al3 (Er, Zr) particles and nanoscale Al3Nb particles are distributed in the grains, and the nanoscale Al3 (Er, Zr) particles and the nanoscale Al3Nb particles are located in the grains of different equiaxed nanoscale alpha-Al grains; a soft phase alpha-Al matrix formed by equiaxial nanoscale alpha-Al grains and nano hard phase particles jointly form a unique soft / hard heterostructure. The laser powder bed fused heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy provided by the invention has excellent obdurability, thermal stability and wear resistance, and has wide application prospects in the fields of rail transit, new energy automobiles, aerospace and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum alloy additive manufacturing, and in particular relates to a laser powder bed melting heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloy and a method and application thereof. Background Art

[0002] As a representative of lightweight structural materials, aluminum alloys occupy an important position in aerospace vehicle skins, automobile body frames, rail transit components, and other fields due to their low density (approximately 2.7g / cm³), excellent specific strength (strength / density ratio), and good formability. Among them, Al-Mg aluminum alloys (such as 5052 and 5083) have good welding properties and resistance to marine corrosion due to the solid solution strengthening effect of magnesium, making them the preferred materials for scenarios such as ship decks and storage tanks. However, the room temperature tensile strength of traditional Al-Mg alloys is generally lower than 400MPa (for example, the typical value of 5083-H116 alloy is 290MPa), and their yield strength decreases significantly when the temperature exceeds 200°C, which seriously restricts their application in high-temperature scenarios such as engine compartments and hot end components of supersonic aircraft.

[0003] In recent years, researchers have introduced the rare earth elements erbium (Er) and zirconium (Zr) into Al-Mg alloys through microalloying. Due to their extremely low solid solubility in the aluminum matrix, Er and Zr preferentially react with Al during rapid solidification to form nanoscale Al3(Er,Zr) precipitates with an L12 structure. These coherent precipitates can hinder dislocation motion through an Orowan bypass mechanism and inhibit grain boundary migration, thereby improving the alloy's room-temperature strength and high-temperature stability. Despite this, the strengthening effect of a single rare earth element still faces the following challenges: Er / Zr additions are constrained by cost and process feasibility, resulting in a limited Al3(Er,Zr) phase volume fraction and insufficient precipitate density, making it difficult to achieve higher strength requirements. Furthermore, when the service temperature exceeds 400°C, the Al3(Er,Zr) phase undergoes Ostwald ripening, weakening the pinning effect. In addition, the strengthening mode that solely relies on Al3(Er,Zr) precipitation phase leads to a lack of high-hardness dispersed phase support at the grain boundaries, which easily induces grain boundary sliding and plastic deformation under the action of friction contact stress, resulting in significant shortcomings in the friction and wear performance of this alloy system. Summary of the Invention

[0004] In view of this, the present invention provides a laser powder bed melt heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy and a method and application. The laser powder bed melt heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy has excellent strength and toughness, thermal stability and wear resistance, and has broad application prospects in rail transportation, new energy vehicles, aerospace and other fields.

[0005] The first object of the present invention is to provide a laser powder bed melted heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy.

[0006] The second object of the present invention is to provide a method for laser powder bed melting of heterogeneous multiphase nanoparticles to synergistically strengthen aluminum-based alloys.

[0007] The third object of the present invention is to provide an application method of laser powder bed melting of heterogeneous multiphase nanoparticles to synergistically reinforce aluminum-based alloys.

[0008] The first object of the present invention can be achieved by adopting the following technical solutions: A laser powder bed melt heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy, the laser powder bed melt heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy consisting of equiaxed nanoscale α-Al grains; nanoscale hard phase particles are dispersed at the grain boundaries of the equiaxed nanoscale α-Al grains, nanoscale Al3(Er, Zr) particles and nanoscale Al3Nb particles are distributed within the grains, and the nanoscale Al3(Er, Zr) particles and nanoscale Al3Nb particles are located within the grains of different equiaxed nanoscale α-Al grains; a soft phase α-Al matrix composed of the equiaxed nanoscale α-Al grains and the nanoscale hard phase particles together constitute a unique soft / hard heterogeneous structure; wherein the nanoscale hard phase particles include nanoscale Al2CuMg particles, nanoscale Mg2Si particles and nanoscale Al5Mo particles.

[0009] Furthermore, the grain size of the equiaxed nanoscale α-Al grains is 450~500nm, the grain sizes of the nanoscale Al3(Er,Zr) and Al3Nb particles are 25~35nm and 20~35nm, respectively; the grain sizes of the nanoscale Al2CuMg, Mg2Si and Al5Mo particles are 35~50nm, 40~55nm and 50~70nm, respectively.

[0010] Furthermore, the nano-scale Al3(Er, Zr) particles and nano-scale Al3Nb particles act as efficient heterogeneous nucleating agents, promoting the formation of equiaxed nano-scale α-Al grains and playing a role in grain refinement strengthening; the soft / hard heterogeneous structure plays a role in heterogeneous deformation-induced strengthening.

[0011] Furthermore, the laser powder bed melt heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy after aging treatment has a yield strength of 560-660 MPa, a tensile strength of 620-850 MPa, and an elongation of 6-15%; the softening temperature is increased to 525-550°C; and the wear rate is 0.808×10 -3 ~1.616×10 -3 mm 3 / (N·m).

[0012] The second object of the present invention can be achieved by adopting the following technical solutions: A method for laser powder bed melting of heterogeneous multiphase nanoparticles to synergistically reinforce aluminum-based alloys comprises the following steps: S1: uniformly mixing aluminum-based alloy composite powders in a mechanical powder mixer, and then vacuum drying the powders; wherein the aluminum-based alloy composite powders have a chemical composition of Mg 4.5-4.7 wt.%, Er 0.6-0.8 wt.%, Zr 0.6-0.8 wt.%, Cu 0.5-5 wt.%, Nb 0.5-3 wt.%, MoSi 2 0.2-3 wt.%, and the balance is Al; the aluminum-based alloy composite powders have a particle size of 15-53 μm and a powder purity higher than 99.9%; S2: Build a 3D model and perform layered slicing. Generate a series of laser selective melting scanning trajectories for the primary melting process and in-situ high-speed secondary melting scanning trajectories based on the slice contour information. S3: Pour the dried composite powder into the powder chamber in the printer, fix the substrate on the forming platform, close the chamber door, and then turn on the fan to introduce argon gas to make the oxygen content in the sealed chamber reach the set value; S4: Spreading powder and performing initial melting using laser; S5: In-situ high-speed secondary melting using laser; S6: repeat steps S4 and S5 until the printing of heterogeneous multiphase nanoparticle-synergistically reinforced aluminum-based alloy is completed; S7: The printed heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy is heat treated to promote the precipitation of multiphase nanoparticles to obtain the final heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy.

[0013] Furthermore, in step S4, the process parameters of the initial melting are: laser power of 200~1000W, laser scanning rate of 600~1800mm / s, laser spot diameter of 100μm, scanning spacing of 50~80μm, powder layer thickness of 25~30μm, and interlayer laser scanning direction rotation angle of 67°.

[0014] Furthermore, in step S5, the in-situ high-speed secondary melting process parameters are: laser power of 200~1000W, laser scanning rate of 3000~8000mm / s, laser spot diameter of 100μm, scanning spacing of 50~80μm, powder layer thickness of 25~30μm, and interlayer laser scanning direction rotation angle of 67°.

[0015] Furthermore, the heat treatment in step S7 is: aging treatment at 250-500° C. for 2-6 hours, followed by air cooling.

[0016] Furthermore, the substrate is an aluminum alloy, and the set value of the oxygen content is 200-1000 ppm.

[0017] The third object of the present invention can be achieved by adopting the following technical solutions: A method for applying laser powder bed fusion heterogeneous multiphase nanoparticles to synergistically reinforce aluminum-based alloys, based on the application of the above-mentioned laser powder bed fusion heterogeneous multiphase nanoparticles to synergistically reinforced aluminum-based alloys or the laser powder bed fusion heterogeneous multiphase nanoparticles to synergistically reinforced aluminum-based alloys prepared by the above-mentioned method in the fields of rail transportation, new energy vehicles and aerospace technology.

[0018] The present invention has the following beneficial effects compared to the prior art: (1) The laser powder bed melt heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy provided by the present invention is composed entirely of equiaxed nanoscale α-Al grains. Al3(Er,Zr) and Al3Nb nanoparticles are distributed within the equiaxed nanoscale α-Al grains, acting as efficient heterogeneous nucleating agents to promote the formation of equiaxed nanoscale α-Al grains and achieve grain refinement through the Hall-Petch effect. At the same time, Al2CuMg, Mg2Si and Al5Mo nanoscale hard phase particles are dispersed at the grain boundaries of the equiaxed nanoscale α-Al grains, forming a unique soft / hard heterogeneous structure together with the soft phase α-Al matrix, which synergistically improves strength through heterogeneous deformation-induced strengthening, dislocation pinning and load transfer. The intracrystalline nanoparticles stabilize the lattice structure by hindering dislocation climb, and the hard nanoparticles at the grain boundaries inhibit high-temperature grain boundary migration and grain coarsening through pinning to improve thermal stability. At the same time, they act as a high-hardness barrier to directly resist wear and improve wear resistance.

[0019] (2) The laser powder bed melt heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy provided by the present invention has a yield strength of 560-660 MPa, a tensile strength of 620-850 MPa, and an elongation of 6-15%; the softening temperature is increased to 525-550°C; the wear rate is 0.808×10 -3 ~1.616×10 -3 mm 3 / (N·m). BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0021] Figure 1Schematic diagram of the microstructure of laser powder bed melted heterogeneous multiphase nanoparticles synergistically reinforced aluminum-based alloys according to Examples 1 to 3 of the present invention.

[0022] Figure 2 Schematic diagram of the apparatus and laser scanning strategy for preparing heterogeneous multiphase nanoparticle-synergistically reinforced aluminum-based alloys by laser powder bed fusion according to Examples 1 to 3 of the present invention.

[0023] in, Figure 2 middle: 1- galvanometer, 2- laser, 3- scraper, 4- powder chamber, 5- printed part, 6- substrate, 7- powder recovery chamber, 8- forming table. DETAILED DESCRIPTION

[0024] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. It should be understood that the specific embodiments described are only used to explain this application and are not used to limit this application.

[0025] Example 1: The method provided in this embodiment for laser powder bed melting of heterogeneous multiphase nanoparticles to synergistically reinforce aluminum-based alloys specifically comprises the following steps: (1) Powders with a purity of more than 99.9% are selected, and the contents of the components of the aluminum-based alloy composite powder are: Mg 4.5wt.%, Er 0.6wt.%, Zr 0.6wt.%, Cu 2.0wt.%, Nb 1wt.%, MoSi 20.6wt.%, and the balance is Al; (2) The weighed composite powder was placed in a powder mixer and mechanically mixed for 3 h at a speed of 49.5 r / min, and then placed in a vacuum drying oven and dried at 80 °C for 3 h; (3) A 7mm×15mm×8mm cuboid 3D model was created in advance using 3D software and sliced ​​into layers with a thickness of 25μm. The STL file was then exported and copied to the computer control system. A series of laser selective melting scanning trajectories for the primary melting process and in-situ high-speed secondary melting scanning trajectories were generated based on the slice contour information. (4) Pour the dried composite powder into the printing powder feeding cabin. Use the aluminum alloy plate that has been rust-removed and sandblasted as the base material to level the forming platform and scraper. Then close the cabin door, turn on the fan, and introduce argon gas to make the oxygen content in the sealed cabin reach 800ppm; (5) Turn on the laser controller and use the computer control system to set the initial melting process parameters as follows: laser power 300 W, laser scanning rate 1000 mm / s, laser spot diameter 100 μm, scanning spacing 80 μm, powder layer thickness 25 μm, and interlayer laser scanning direction rotation angle 67°; (6) Based on the primary melting process parameters, the in-situ high-speed secondary melting process parameters were set as follows: laser power of 300 W, laser scanning rate of 4000 mm / s, laser spot diameter of 100 μm, scanning spacing of 80 μm, powder layer thickness of 25 μm, and interlayer laser scanning direction rotation angle of 67°; (7) According to the scanning trajectory generated by the program settings, the powder is melted through the process parameters of the primary melting to form a process part, and then the process part is subjected to in-situ high-speed secondary melting; the steps of powder laying, primary melting and secondary melting are repeated until a three-dimensional solid aluminum-based alloy that meets the size is formed by layer-by-layer accumulation, and the printing work is completed; (8) The substrate is removed by wire cutting to obtain a well-formed heterogeneous multiphase nanoparticle-synergistically reinforced aluminum-based alloy; (9) The alloy was placed in a muffle furnace and aged at 350°C for 2.5 h, followed by air cooling. The heat-treated specimens were then subjected to phase, microstructure, and composition analysis, followed by tensile strength testing, thermal stability testing, and friction and wear performance testing.

[0026] The microstructure of the laser powder bed melted heterogeneous multiphase nanoparticles synergistically reinforced aluminum-based alloy prepared in this example after heat treatment is shown in FIG. Figure 1 The average grain size of the equiaxed nano-α-Al grains is 483 nm, the average grain sizes of the Al3(Er,Zr) and Al3Nb nanoparticles are 32 nm and 31 nm, respectively, and the average grain sizes of the Al2CuMg, Mg2Si, and Al5Mo nanoparticles are 42 nm, 50 nm, and 63 nm, respectively. The alloy has a yield strength of 576 MPa, a tensile strength of 643 MPa, an elongation of 12.4%, and a wear rate of 1.414×10 -3 mm 3 / (N·m). Compared with AlMgErZr alloy, its tensile strength is increased by 26.3%, the softening temperature is increased by 25℃, and the wear rate is reduced by 65%.

[0027] Example 2: The method provided in this embodiment for laser powder bed melting of heterogeneous multiphase nanoparticles to synergistically reinforce aluminum-based alloys specifically comprises the following steps: (1) Powders with a purity of more than 99.9% are selected, and the contents of the components of the aluminum-based alloy composite powder are: Mg 4.7wt.%, Er 0.7wt.%, Zr 0.8wt.%, Cu 3.5wt.%, Nb 2wt.%, MoSi 21.5wt.%, and the balance is Al; (2) The weighed composite powder was placed in a powder mixer and mechanically mixed for 3 h at a speed of 49.5 r / min, and then placed in a vacuum drying oven and dried at 80 °C for 3 h; (3) A 7mm×15mm×8mm cuboid 3D model was created in advance using 3D software and sliced ​​in layers with a slice thickness of 30μm. The STL file was then exported and copied to the computer control system. A series of laser selective melting primary melting scanning trajectories and in-situ high-speed secondary melting scanning trajectories were generated based on the slice contour information. (4) Pour the dried composite powder into the printing powder feeding cabin. Use the aluminum alloy plate that has been rust-removed and sandblasted as the base material to level the forming platform and scraper. Then close the cabin door, turn on the fan, and introduce argon gas to make the oxygen content in the sealed cabin reach 1000ppm; (5) Turn on the laser controller and use the computer control system to set the initial melting process parameters as follows: laser power 450 W, laser scanning rate 1200 mm / s, laser spot diameter 100 μm, scanning spacing 80 μm, powder layer thickness 30 μm, and interlayer laser scanning direction rotation angle 67°; (6) Based on the primary melting process parameters, the high-speed secondary melting process parameters were set as follows: laser power 450 W, laser scanning rate 5000 mm / s, laser spot diameter 100 μm, scanning spacing 80 μm, powder layer thickness 30 μm, and interlayer laser scanning direction rotation angle 67°; (7) According to the scanning trajectory generated by the program settings, the powder is melted through the process parameters of the initial melting to form a process part, and then the process part is subjected to high-speed secondary melting; the steps of powder laying, initial melting and secondary melting are repeated until a three-dimensional solid aluminum-based alloy that meets the size is formed by layer-by-layer accumulation, and the printing work is completed; (8) The substrate is removed by wire cutting to obtain a well-formed heterogeneous multiphase nanoparticle-synergistically reinforced aluminum-based alloy; (9) The alloy was placed in a muffle furnace and aged at 375°C for 4 h, followed by air cooling. The heat-treated specimens were then subjected to phase, microstructure, and composition analysis, followed by tensile strength testing, thermal stability testing, and friction and wear performance testing.

[0028] The microstructure of the laser powder bed melted heterogeneous multiphase nanoparticles synergistically reinforced aluminum-based alloy prepared in this example after heat treatment is shown in FIG. Figure 1The average grain size of the equiaxed nano-α-Al grains is 461 nm, the average grain sizes of the Al3(Er,Zr) and Al3Nb nanoparticles are 29 nm and 26 nm, respectively, and the average grain sizes of the Al2CuMg, Mg2Si, and Al5Mo nanoparticles are 39 nm, 52 nm, and 61 nm, respectively. The alloy has a yield strength of 618 MPa, a tensile strength of 706 MPa, an elongation of 9.5%, and a wear rate of 1.091×10 -3 mm 3 / (N·m). Compared with AlMgErZr alloy, its tensile strength is increased by 38.7%, the softening temperature is increased by 30℃, and the wear rate is reduced by 73%.

[0029] Example 3: The method provided in this embodiment for laser powder bed melting of heterogeneous multiphase nanoparticles to synergistically reinforce aluminum-based alloys specifically comprises the following steps: (1) Powders with a purity of more than 99.9% are selected, and the contents of the components of the aluminum-based alloy composite powder are: Mg 4.6wt.%, Er 0.8wt.%, Zr 0.7wt.%, Cu 5wt.%, Nb 2.5wt.%, MoSi 22wt.%, and the balance is Al; (2) The weighed composite powder was placed in a powder mixer and mechanically mixed for 3 h at a speed of 49.5 r / min, and then placed in a vacuum drying oven and dried at 80 °C for 3 h; (3) A 7mm×15mm×8mm cuboid 3D model was created in advance using 3D software and sliced ​​in layers with a slice thickness of 30μm. The STL file was then exported and copied to the computer control system. A series of laser selective melting primary melting scanning trajectories and in-situ high-speed secondary melting scanning trajectories were generated based on the slice contour information. (4) Pour the dried composite powder into the printing powder feeding cabin. Use the aluminum alloy plate that has been rust-removed and sandblasted as the base material to level the forming platform and scraper. Then close the cabin door, turn on the fan, and introduce argon gas to make the oxygen content in the sealed cabin reach 500ppm; (5) Turn on the laser controller and use the computer control system to set the optimal primary melting process parameters as follows: laser power of 500 W, laser scanning rate of 1500 mm / s, laser spot diameter of 100 μm, scanning spacing of 80 μm, powder layer thickness of 30 μm, and interlayer laser scanning direction rotation angle of 67°; (6) Based on the primary melting process parameters, the high-speed secondary melting process parameters were set as follows: laser power of 500 W, laser scanning rate of 6000 mm / s, laser spot diameter of 100 μm, scanning spacing of 80 μm, powder layer thickness of 30 μm, and interlayer laser scanning direction rotation angle of 67°.

[0030] (7) According to the scanning trajectory generated by the program settings, the powder is melted through the process parameters of the initial melting to form a process part, and then the process part is subjected to high-speed secondary melting; the steps of powder laying, initial melting and secondary melting are repeated until a three-dimensional solid aluminum-based alloy that meets the size is formed by layer-by-layer accumulation, and the printing work is completed; (8) The substrate is removed by wire cutting to obtain a well-formed heterogeneous multiphase nanoparticle-synergistically reinforced aluminum-based alloy; (9) The alloy was placed in a muffle furnace and aged at 400°C for 3.5 h, followed by air cooling. The heat-treated specimens were then subjected to phase, microstructure, and composition analysis, followed by tensile strength testing, thermal stability testing, and friction and wear performance testing.

[0031] The microstructure of the laser powder bed melted heterogeneous multiphase nanoparticles synergistically reinforced aluminum-based alloy prepared in this example after heat treatment is shown in FIG. Figure 1 The average grain size of the equiaxed nano-α-Al grains is 452 nm, the average grain sizes of the Al3(Er,Zr) and Al3Nb nanoparticles are 26 nm and 23 nm, respectively, and the average grain sizes of the Al2CuMg, Mg2Si, and Al5Mo nanoparticles are 38 nm, 46 nm, and 58 nm, respectively. The alloy has a yield strength of 655 MPa, a tensile strength of 749 MPa, an elongation of 7.2%, and a wear rate of 0.864×10 -3 mm 3 / (N·m). Compared with AlMgErZr alloy, its tensile strength is increased by 47.1%, the softening temperature is increased by 35℃, and the wear rate is reduced by 78.6%.

[0032] The three aforementioned examples achieve different levels of high strength, heat resistance, and wear resistance through laser powder bed fusion heterogeneous multiphase nanoparticle synergistic reinforcement of aluminum-based alloys by varying the chemical composition, printing process parameters, and heat treatment process parameters of the aluminum-based alloy composite powder. It is understood that further examples (different aluminum-based alloy composite powder chemical compositions, laser powder bed fusion process parameters, and heat treatment process parameters) can yield even more high strength, heat resistance, and wear resistance laser powder bed fusion heterogeneous multiphase nanoparticle synergistic reinforcement of aluminum-based alloys, which are not listed in the examples of this invention. The laser powder bed fusion heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloys obtained through multiple experiments are composed entirely of equiaxed nanoscale α-Al grains (size 450-500 nm). Al3(Er,Zr) and Al3Nb nanoparticles, with sizes of 25-35 nm and 20-35 nm, respectively, are distributed within the equiaxed nanoscale α-Al grains, acting as highly efficient heterogeneous nucleating agents to promote the formation of the equiaxed nanoscale α-Al grains. At the same time, Al2CuMg, Mg2Si and Al5Mo nanoparticles (as hard phases) are dispersed at the grain boundaries of equiaxed nanoscale α-Al grains (as soft phases) with sizes of 35~50nm, 40~55nm and 50~70nm, respectively, forming a unique soft (α-Al matrix) / hard (intermetallic compound particles) heterostructure with the α-Al matrix.

[0033] In Examples 1 to 3, the device and laser scanning strategy for preparing heterogeneous multiphase nanoparticles synergistically reinforced aluminum-based alloys by laser powder bed fusion can be referred to Figure 2 .

[0034] In summary, in order to break through the bottlenecks of strength, thermal stability and wear resistance of existing AlMgErZr alloys, the present invention innovatively introduces copper (Cu), niobium (Nb) and molybdenum disilicide (MoSi2) at the same time. Cu and Nb form Al2CuMg and Al3Nb nanoparticles respectively during the laser powder bed melting process; MoSi2 decomposes into Mo and Si in situ during the laser powder bed melting process, and interacts with Al and Mg elements to form Al5Mo and Mg2Si nanoparticles respectively; Al3(Er, Zr) is formed in situ during the laser powder bed melting process; Al3(Er, Zr) and Al3Nb nanoparticles in the crystal act as efficient heterogeneous nucleating agents, significantly refining the grains; Al2CuMg, Mg2Si and Al5Mo nanoparticles on the grain boundaries and the α-Al matrix together constitute a unique soft (α-Al matrix) / hard (intermetallic compound particles) heterostructure, which synergistically improves strength through heterogeneous deformation-induced strengthening, dislocation pinning and load transfer. Intracrystalline nanoparticles stabilize the lattice structure by hindering dislocation climb, while hard nanoparticles at grain boundaries inhibit high-temperature grain boundary migration and grain coarsening through pinning, improving thermal stability. They also act as a high-hardness barrier to directly resist wear, enhancing wear resistance. This synergistic design of "intracrystalline nanorefinement + grain boundary multiphase dispersion" offers a new approach to the preparation of high-performance aluminum-based materials.

[0035] The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solution and inventive concept of the present invention within the scope disclosed by the present invention, which falls within the scope of protection of the present invention.

Claims

1. A laser powder bed melted heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy, characterized in that: The laser powder bed melt heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy is composed of equiaxed nano-scale α-Al grains; nano-hard phase particles are dispersed at the grain boundaries of the equiaxed nano-scale α-Al grains, and nano-scale Al3(Er, Zr) particles and nano-scale Al3Nb particles are distributed in the grains, and the nano-scale Al3(Er, Zr) particles and nano-scale Al3Nb particles are located in the grains of different equiaxed nano-scale α-Al grains; the soft phase α-Al matrix composed of the equiaxed nano-scale α-Al grains and the nano-hard phase particles together constitute a unique soft / hard heterogeneous structure; wherein the nano-hard phase particles include nano-scale Al2CuMg particles, nano-scale Mg2Si particles and nano-scale Al5Mo particles.

2. The laser powder bed fusion heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy according to claim 1, characterized in that: The grain size of the equiaxed nanoscale α-Al grains is 450~500nm, the grain sizes of the nanoscale Al3(Er,Zr) and Al3Nb particles are 25~35nm and 20~35nm respectively; the grain sizes of the nanoscale Al2CuMg, Mg2Si and Al5Mo particles are 35~50nm, 40~55nm and 50~70nm respectively.

3. The laser powder bed fusion heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy according to claim 1, characterized in that: The nano-scale Al3(Er, Zr) particles and nano-scale Al3Nb particles act as efficient heterogeneous nucleating agents, promoting the formation of equiaxed nano-scale α-Al grains and playing a role in grain refinement strengthening; the soft / hard heterogeneous structure plays a role in heterogeneous deformation-induced strengthening.

4. The laser powder bed fused heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy according to any one of claims 1 to 3, characterized in that: The laser powder bed melt heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy has a yield strength of 560-660 MPa, a tensile strength of 620-850 MPa, and an elongation of 6-15% after aging treatment; the softening temperature is increased to 525-550°C; the wear rate is 0.808×10 -3 ~1.616×10 -3 mm 3 / (N·m).

5. A method for laser powder bed melting of heterogeneous multiphase nanoparticles to synergistically reinforce aluminum-based alloys, characterized in that: The following steps are involved: S1: uniformly mixing aluminum-based alloy composite powders in a mechanical powder mixer, and then vacuum drying the powders; wherein the aluminum-based alloy composite powders have a chemical composition of Mg 4.5-4.7 wt.%, Er 0.6-0.8 wt.%, Zr 0.6-0.8 wt.%, Cu 0.5-5 wt.%, Nb 0.5-3 wt.%, MoSi 2 0.2-3 wt.%, and the balance is Al; the aluminum-based alloy composite powders have a particle size of 15-53 μm and a powder purity higher than 99.9%; S2: Build a 3D model and perform layered slicing. Generate a series of laser selective melting scanning trajectories for the primary melting process and in-situ high-speed secondary melting scanning trajectories based on the slice contour information. S3: Pour the dried composite powder into the powder chamber in the printer, fix the substrate on the forming platform, close the chamber door, and then turn on the fan to introduce argon gas to make the oxygen content in the sealed chamber reach the set value; S4: Spreading powder and performing initial melting using laser; S5: In-situ high-speed secondary melting using laser; S6: repeat steps S4 and S5 until the printing of heterogeneous multiphase nanoparticle-synergistically reinforced aluminum-based alloy is completed; S7: The printed heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy is heat treated to promote the precipitation of multiphase nanoparticles to obtain the final heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy.

6. The method according to claim 5, characterized in that The process parameters for the initial melting in step S4 are: laser power of 200-1000 W, laser scanning rate of 600-1800 mm / s, laser spot diameter of 100 μm, scanning spacing of 50-80 μm, powder layer thickness of 25-30 μm, and interlayer laser scanning direction rotation angle of 67°.

7. The method according to claim 5, characterized in that The process parameters of the in-situ high-speed secondary melting in step S5 are as follows: laser power of 200-1000 W, laser scanning rate of 3000-8000 mm / s, laser spot diameter of 100 μm, scanning spacing of 50-80 μm, powder layer thickness of 25-30 μm, and interlayer laser scanning direction rotation angle of 67°.

8. The method according to claim 5, characterized in that The heat treatment in step S7 is: aging treatment at 250-500°C for 2-6 hours, followed by air cooling.

9. The method according to any one of claims 5 to 8, characterized in that The substrate is aluminum alloy, and the set value of oxygen content is 200-1000ppm.

10. An application method of laser powder bed melting heterogeneous multiphase nanoparticles to synergistically reinforce aluminum-based alloys, characterized in that: Application of the laser powder bed fused heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy according to any one of claims 1 to 4 or the laser powder bed fused heterogeneous multiphase nanoparticle synergistically reinforced aluminum-based alloy prepared by the method according to any one of claims 5 to 9 in the fields of rail transportation, new energy vehicles and aerospace technology.

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