Laser powder bed fusion of isomorphic multi-phase nanoparticles synergistically reinforced aluminum-based alloys, methods and applications

Abstract

The application discloses a laser powder bed fusion isomorphic multi-phase nanoparticle synergistically reinforced aluminum-based alloy and a method and application thereof. The laser powder bed fusion isomorphic multi-phase nanoparticle synergistically reinforced aluminum-based alloy is composed of equiaxed nanoscale alpha-Al grains. Nanoscale hard phase particles are dispersedly distributed at grain boundaries of the equiaxed nanoscale alpha-Al grains, and nanoscale Al3(Er, Zr) particles and nanoscale Al3Nb particles are distributed in the grains. 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 composed of the equiaxed nanoscale alpha-Al grains and the nanoscale hard phase particles jointly form a unique soft / hard heterogeneous structure. The laser powder bed fusion isomorphic multi-phase nanoparticle synergistically reinforced aluminum-based alloy has excellent strength, toughness, thermal stability and wear resistance, and has a wide application prospect in the fields of rail transportation, new energy vehicles and aerospace.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy additive manufacturing technology, and in particular relates to a method and application of laser powder bed melting heterogeneous multiphase nanoparticles synergistically reinforcing aluminum-based alloys. Background Technology

[0002] Aluminum alloys, as a representative of lightweight structural materials, occupy an important position in aerospace vehicle skins, automotive body frames, and rail transit components due to their low density (approximately 2.7 g / cm³), excellent specific strength (strength / density ratio), and good formability. Among them, Al-Mg aluminum alloys (such as 5052 and 5083), due to the solid solution strengthening effect of magnesium, possess both good weldability and resistance to marine corrosion, making them the preferred materials for applications such as ship decks and storage tanks. However, the room temperature tensile strength of traditional Al-Mg alloys is generally below 400 MPa (e.g., the typical value of 5083-H116 alloy is 290 MPa), and their yield strength decreases significantly at temperatures exceeding 200°C, severely limiting their application in high-temperature environments such as engine nacelles and hot-end components of supersonic aircraft.

[0003] In recent years, researchers have introduced rare earth elements erbium (Er) and zirconium (Zr) into Al-Mg aluminum alloys using microalloying strategies. Due to the extremely low solid solubility of Er and Zr in the aluminum matrix, they preferentially react with Al during rapid solidification to form L12-structured nanoscale Al3(Er,Zr) precipitates. These coherent precipitates can hinder dislocation movement through the Orowan bypass mechanism and suppress grain boundary migration, thereby improving the room-temperature strength and high-temperature stability of the alloy. Nevertheless, the strengthening effect of a single rare earth element still faces the following challenges: the Er / Zr addition amount is limited by cost and process feasibility, resulting in a limited volume fraction of the Al3(Er,Zr) phase and insufficient precipitate density, making it difficult to achieve higher strength requirements; when the service temperature exceeds 400℃, the Al3(Er,Zr) phase undergoes Ostwald ripening, weakening the pinning effect. Furthermore, the strengthening mode that relies solely on Al3(Er,Zr) precipitates results in a lack of high-hardness dispersed phase support at the grain boundaries. Under frictional contact stress, this easily leads to grain boundary slip and plastic deformation, resulting in a significant shortcoming 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 melting heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloy, method and application. The laser powder bed melting heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloy has excellent strength, toughness, thermal stability and wear resistance, and has broad application prospects in the fields of rail transportation, new energy vehicles and aerospace.

[0005] The first objective of this invention is to provide a laser powder bed melting heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloy.

[0006] The second objective of this invention is to provide a method for synergistic reinforcement of aluminum-based alloys by laser powder bed melting of heterogeneous multiphase nanoparticles.

[0007] The third objective of this invention is to provide a method for applying laser powder bed melting heterogeneous multiphase nanoparticles to synergistically reinforce aluminum-based alloys.

[0008] The first objective of this invention can be achieved by adopting the following technical solution:

[0009] A laser-fused powder bed heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloy is disclosed. This alloy is composed of equiaxed nanoscale α-Al grains. Nanoscale hard phase particles are dispersed at the grain boundaries of the equiaxed nanoscale α-Al grains, and nanoscale Al3(Er,Zr) particles and nanoscale Al3Nb particles are distributed within the grains. These particles are located within different equiaxed nanoscale α-Al grains. The soft α-Al matrix composed of the equiaxed nanoscale α-Al grains and the nanoscale hard phase particles together form a unique soft / hard heterostructure. The nanoscale hard phase particles include nanoscale Al2CuMg particles, nanoscale Mg2Si particles, and nanoscale Al5Mo particles.

[0010] Furthermore, the equiaxed nanoscale α-Al grains have a grain size of 450~500nm, the nanoscale Al3(Er,Zr) and Al3Nb particles have grain sizes of 25~35nm and 20~35nm, respectively; and the nanoscale Al2CuMg, Mg2Si and Al5Mo particles have grain sizes of 35~50nm, 40~55nm and 50~70nm, respectively.

[0011] Furthermore, the nanoscale Al3(Er,Zr) particles and nanoscale Al3Nb particles serve as highly efficient heterogeneous nucleating agents, promoting the formation of equiaxed nanoscale α-Al grains and playing a grain-refining strengthening role; the soft / hard heterostructure plays a heterogeneous deformation-induced strengthening role.

[0012] Furthermore, the laser-reinforced aluminum-based alloy with heterogeneous multiphase nanoparticles, after aging treatment, exhibits a yield strength of 560–660 MPa, a tensile strength of 620–850 MPa, and an elongation of 6–15%; its softening temperature is increased to 525–550 °C; and its wear rate is 0.808 × 10⁻⁶. -3 ~1.616×10 -3 mm 3 / (N·m).

[0013] The second objective of this invention can be achieved by adopting the following technical solution:

[0014] A method for laser powder bed melting of heterogeneous multiphase nanoparticles to synergistically reinforce aluminum-based alloys includes the following steps:

[0015] S1: The aluminum-based alloy composite powder is uniformly mixed using a mechanical powder mixer and then subjected to vacuum drying. The chemical composition of the aluminum-based alloy composite powder is: 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.%, MoSi2 0.2~3 wt.%, with the balance being Al. The particle size of the aluminum-based alloy composite powder is 15~53 μm, and the powder purity is higher than 99.9%.

[0016] S2: Establish a 3D model and perform layered slicing. Based on the slice contour information, generate a series of laser selective melting and forming primary melting scanning trajectories and in-situ high-speed secondary melting scanning trajectories.

[0017] S3: Pour the dried composite powder into the powder chamber of the printer, fix the substrate on the forming platform, close the chamber door, and then turn on the fan to introduce argon gas so that the oxygen content in the sealed chamber reaches the set value.

[0018] S4: Spread powder and use laser for initial melting;

[0019] S5: In-situ high-speed secondary melting using laser;

[0020] S6: Repeat steps S4 and S5 until the printing of the heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloy is completed;

[0021] S7: Heat-treat the printed heterogeneous multiphase nanoparticle synergistic reinforced aluminum-based alloy to promote the precipitation of multiphase nanoparticles and obtain the final heterogeneous multiphase nanoparticle synergistic reinforced aluminum-based alloy.

[0022] Furthermore, in step S4, the process parameters for 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°.

[0023] Furthermore, in step S5, the in-situ high-speed secondary melting process parameters are as follows: laser power is 200~1000W, laser scanning rate is 3000~8000mm / s, laser spot diameter is 100μm, scanning spacing is 50~80μm, powder layer thickness is 25~30μm, and the rotation angle of the interlayer laser scanning direction is 67°.

[0024] Furthermore, the heat treatment in step S7 is as follows: aging treatment at 250~500°C for 2~6 hours, followed by air cooling.

[0025] Furthermore, the substrate is an aluminum alloy, and the oxygen content is set at 200~1000ppm.

[0026] The third objective of this invention can be achieved by adopting the following technical solution:

[0027] A method for applying laser-driven powder bed melting heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloys, and the application of the above-mentioned laser-driven powder bed melting heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloys or the laser-driven powder bed melting heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloys prepared by the above method in the fields of rail transit, new energy vehicles and aerospace technology.

[0028] The present invention has the following advantages over the prior art:

[0029] (1) The laser powder bed melting heterogeneous multiphase nanoparticle synergistic reinforcement 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-Page 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 heterostructure together with the soft phase α-Al matrix, which synergistically improves strength through heterogeneous deformation-induced strengthening, dislocation pinning and load transfer. The nanoparticles within the grains stabilize the lattice structure by hindering dislocation climb, while the hard nanoparticles at the grain boundaries inhibit high-temperature grain boundary migration and grain coarsening through pinning to improve thermal stability, and at the same time act as a high-hardness barrier to directly resist wear and improve wear resistance.

[0030] (2) The aluminum-based alloy with synergistic reinforcement by laser powder bed melting heterogeneous multiphase nanoparticles provided by the present invention has a yield strength of 560~660MPa, a tensile strength of 620~850MPa, and an elongation of 6~15%; the softening temperature is increased to 525~550℃; and the wear rate is 0.808×10 -3 ~1.616×10 -3 mm 3 / (N·m). Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0032] Figure 1 These are schematic diagrams of the microstructure of aluminum-based alloys synergistically reinforced by laser powder bed melting heterogeneous multiphase nanoparticles in Examples 1-3 of the present invention.

[0033] Figure 2 The diagram shows the apparatus and laser scanning strategy for preparing heterogeneous multiphase nanoparticle-synergistically reinforced aluminum-based alloys by laser powder bed melting in Examples 1-3 of this invention.

[0034] in, Figure 2 middle:

[0035] 1-Galvanometer, 2-Laser, 3-Scraper, 4-Powder chamber, 5-Printed part, 6-Substrate, 7-Powder recovery chamber, 8-Forming table. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. 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. It should be understood that the specific embodiments described are merely used to explain this application and are not intended to limit this application.

[0037] Example 1:

[0038] The method for synergistic reinforcement of aluminum-based alloys by laser powder bed melting of heterogeneous multiphase nanoparticles provides in this embodiment specifically includes the following steps:

[0039] (1) Select powder with a purity of 99.9% or higher. The contents of each component of the aluminum-based alloy composite powder are as follows: Mg 4.5wt.%, Er 0.6wt.%, Zr 0.6wt.%, Cu 2.0wt.%, Nb 1wt.%, MoSi 20.6wt.%, with the balance being Al;

[0040] (2) The weighed composite powder was placed in a powder mixer and mechanically mixed for 3 hours at a speed of 49.5 r / min. Then it was placed in a vacuum drying oven and dried at 80°C for 3 hours.

[0041] (3) A 7mm×15mm×8mm cuboid 3D model was first established using 3D software and layered slicing was performed. The slice thickness was 25μm. Then, the STL file was exported and copied to the computer control system. A series of laser selective melting and forming primary melting scanning trajectories and in-situ high-speed secondary melting scanning trajectories were generated based on the slice contour information.

[0042] (4) Pour the dried composite powder into the printing powder feeding chamber. Use aluminum alloy sheet that has been rust-removed and sandblasted as the substrate, and level the forming platform and scraper. Then close the chamber door, turn on the fan, and introduce argon gas to make the oxygen content in the sealed chamber reach 800ppm;

[0043] (5) Turn on the laser controller and use the computer control system to set the initial melting process parameters as follows: laser power is 300W, laser scanning rate is 1000mm / s, laser spot diameter is 100μm, scanning interval is 80μm, powder layer thickness is 25μm, and the rotation angle of the interlayer laser scanning direction is 67°.

[0044] (6) Based on the initial melting process parameters, the in-situ high-speed secondary melting process parameters are set as follows: laser power is 300W, laser scanning rate is 4000mm / s, laser spot diameter is 100μm, scanning interval is 80μm, powder layer thickness is 25μm, and the rotation angle of the interlayer laser scanning direction is 67°.

[0045] (7) According to the scanning trajectory generated by the program setting, the powder is melted through the process parameters of the first melting to form a process part, and then the process part is melted in situ at high speed. Repeat the powder spreading, first melting and second melting steps until a three-dimensional solid aluminum-based alloy that meets the size is formed by layering. Then the printing work is ended.

[0046] (8) The substrate is removed by wire cutting to obtain a well-formed aluminum-based alloy with synergistic reinforcement of heterogeneous multiphase nanoparticles;

[0047] (9) The above alloy was placed in a muffle furnace and aged at 350°C for 2.5 h, and then air-cooled. The heat-treated sample was then subjected to phase, microstructure and composition analysis, followed by tensile strength test, thermal stability test and tribological test.

[0048] The microstructure of the laser powder bed fusion heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloy prepared in this embodiment after heat treatment is shown in [reference]. Figure 1The average grain size of the equiaxed α-Al nanoparticles is 483 nm, while the average grain sizes of Al3(Er,Zr) and Al3Nb nanoparticles are 32 nm and 31 nm, respectively. The average grain sizes of Al2CuMg, Mg2Si, and Al5Mo nanoparticles are 42 nm, 50 nm, and 63 nm, respectively. This alloy exhibits a yield strength of 576 MPa, a tensile strength of 643 MPa, an elongation of 12.4%, and a wear rate of 1.414 × 10⁻⁶. -3 mm 3 / (N·m). Compared with AlMgErZr alloy, its tensile strength is increased by 26.3%, its softening temperature is increased by 25℃, and its wear rate is reduced by 65%.

[0049] Example 2:

[0050] The method for synergistic reinforcement of aluminum-based alloys by laser powder bed melting of heterogeneous multiphase nanoparticles provides in this embodiment specifically includes the following steps:

[0051] (1) Select powder with a purity of 99.9% or higher. The contents of each component of the aluminum-based alloy composite powder are as follows: Mg 4.7wt.%, Er 0.7wt.%, Zr 0.8wt.%, Cu 3.5wt.%, Nb 2wt.%, MoSi 21.5wt.%, with the balance being Al;

[0052] (2) The weighed composite powder was placed in a powder mixer and mechanically mixed for 3 hours at a speed of 49.5 r / min. Then it was placed in a vacuum drying oven and dried at 80°C for 3 hours.

[0053] (3) A 7mm×15mm×8mm cuboid 3D model was first established using 3D software and layered slicing was performed. The slice thickness was 30μm. Then, the STL file was exported and copied to the computer control system. A series of laser selective melting and forming primary melting scanning trajectories and in-situ high-speed secondary melting scanning trajectories were generated based on the slice contour information.

[0054] (4) Pour the dried composite powder into the printing powder feeding chamber. Use aluminum alloy sheet that has been rust-removed and sandblasted as the substrate, and level the forming platform and scraper. Then close the chamber door, turn on the fan, and introduce argon gas to make the oxygen content in the sealed chamber reach 1000ppm;

[0055] (5) Turn on the laser controller and use the computer control system to set the initial melting process parameters as follows: laser power is 450W, laser scanning rate is 1200mm / s, laser spot diameter is 100μm, scanning interval is 80μm, powder layer thickness is 30μm, and the rotation angle of the interlayer laser scanning direction is 67°.

[0056] (6) Based on the initial melting process parameters, the high-speed secondary melting process parameters are set as follows: laser power is 450W, laser scanning rate is 5000mm / s, laser spot diameter is 100μm, scanning spacing is 80μm, powder layer thickness is 30μm, and the rotation angle of the interlayer laser scanning direction is 67°.

[0057] (7) According to the scanning trajectory generated by the program setting, the powder is melted through the process parameters of the first melting to form a process part, and then the process part is melted at high speed. Repeat the steps of powder spreading, first melting and second melting until a three-dimensional solid aluminum-based alloy that meets the size is formed by layering. Then the printing work is ended.

[0058] (8) The substrate is removed by wire cutting to obtain a well-formed aluminum-based alloy with synergistic reinforcement of heterogeneous multiphase nanoparticles;

[0059] (9) The above alloy was placed in a muffle furnace and aged at 375°C for 4 hours, and then air-cooled. The heat-treated sample was then subjected to phase, microstructure and composition analysis, followed by tensile strength test, thermal stability test and tribological test.

[0060] The microstructure of the laser powder bed fusion heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloy prepared in this embodiment after heat treatment is shown in [reference]. Figure 1 The average grain size of the equiaxed α-Al nanoparticles is 461 nm, while the average grain sizes of Al3(Er,Zr) and Al3Nb nanoparticles are 29 nm and 26 nm, respectively. The average grain sizes of Al2CuMg, Mg2Si, and Al5Mo nanoparticles are 39 nm, 52 nm, and 61 nm, respectively. The alloy exhibits a yield strength of 618 MPa, a tensile strength of 706 MPa, an elongation of 9.5%, and a wear rate of 1.091 × 10⁻⁶. -3 mm 3 / (N·m). Compared with AlMgErZr alloy, its tensile strength is increased by 38.7%, its softening temperature is increased by 30℃, and its wear rate is reduced by 73%.

[0061] Example 3:

[0062] The method for synergistic reinforcement of aluminum-based alloys by laser powder bed melting of heterogeneous multiphase nanoparticles provides in this embodiment specifically includes the following steps:

[0063] (1) Select powder with a purity of 99.9% or higher. The contents of each component of the aluminum-based alloy composite powder are as follows: Mg 4.6wt.%, Er 0.8wt.%, Zr 0.7wt.%, Cu 5wt.%, Nb 2.5wt.%, MoSi 22wt.%, with the balance being Al;

[0064] (2) The weighed composite powder was placed in a powder mixer and mechanically mixed for 3 hours at a speed of 49.5 r / min. Then it was placed in a vacuum drying oven and dried at 80°C for 3 hours.

[0065] (3) A 7mm×15mm×8mm cuboid 3D model was first established using 3D software and layered slicing was performed. The slice thickness was 30μm. Then, the STL file was exported and copied to the computer control system. A series of laser selective melting and forming primary melting scanning trajectories and in-situ high-speed secondary melting scanning trajectories were generated based on the slice contour information.

[0066] (4) Pour the dried composite powder into the printing powder feeding chamber. Use aluminum alloy sheet that has been rust-removed and sandblasted as the substrate, and level the forming platform and scraper. Then close the chamber door, turn on the fan, and introduce argon gas to make the oxygen content in the sealed chamber reach 500ppm;

[0067] (5) Turn on the laser controller and use the computer control system to set the optimal initial melting process parameters as follows: laser power is 500W, laser scanning rate is 1500mm / s, laser spot diameter is 100μm, scanning interval is 80μm, powder layer thickness is 30μm, and the rotation angle of the interlayer laser scanning direction is 67°.

[0068] (6) Based on the initial melting process parameters, the high-speed secondary melting process parameters are set as follows: laser power is 500W, laser scanning rate is 6000mm / s, laser spot diameter is 100μm, scanning spacing is 80μm, powder layer thickness is 30μm, and the rotation angle of the interlayer laser scanning direction is 67°.

[0069] (7) According to the scanning trajectory generated by the program setting, the powder is melted through the process parameters of the first melting to form a process part, and then the process part is melted at high speed. Repeat the steps of powder spreading, first melting and second melting until a three-dimensional solid aluminum-based alloy that meets the size is formed by layering. Then the printing work is ended.

[0070] (8) The substrate is removed by wire cutting to obtain a well-formed aluminum-based alloy with synergistic reinforcement of heterogeneous multiphase nanoparticles;

[0071] (9) The above alloy was placed in a muffle furnace and aged at 400°C for 3.5 h, and then air-cooled. The heat-treated sample was then subjected to phase, microstructure and composition analysis, followed by tensile strength test, thermal stability test and tribological wear test.

[0072] The microstructure of the laser powder bed fusion heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloy prepared in this embodiment after heat treatment is shown in [reference]. Figure 1The average grain size of the equiaxed α-Al nanoparticles is 452 nm, while the average grain sizes of Al3(Er,Zr) and Al3Nb nanoparticles are 26 nm and 23 nm, respectively. The average grain sizes of Al2CuMg, Mg2Si, and Al5Mo nanoparticles are 38 nm, 46 nm, and 58 nm, respectively. This alloy exhibits a yield strength of 655 MPa, a tensile strength of 749 MPa, an elongation of 7.2%, and a wear rate of 0.864 × 10⁻⁶. -3 mm 3 / (N·m). Compared with AlMgErZr alloy, its tensile strength is increased by 47.1%, its softening temperature is increased by 35℃, and its wear rate is reduced by 78.6%.

[0073] The above three embodiments obtained high-strength, heat-resistant, and wear-resistant laser powder bed fusion heterogeneous multiphase nanoparticle synergistic reinforced aluminum-based alloys by changing the chemical composition of the aluminum-based alloy composite powder, printing process parameters, and heat treatment process parameters. It is understood that more high-strength, heat-resistant, and wear-resistant laser powder bed fusion heterogeneous multiphase nanoparticle synergistic reinforced aluminum-based alloys can be obtained through more embodiments (different chemical compositions of aluminum-based alloy composite powders, different laser powder bed fusion process parameters, and heat treatment process parameters), which will not be listed individually in the embodiments of this invention. The laser powder bed fusion heterogeneous multiphase nanoparticle synergistic reinforced aluminum-based alloys obtained through multiple experiments are entirely composed of equiaxed nanoscale α-Al grains (size 450~500nm). Al3(Er,Zr) and Al3Nb nanoparticles are distributed within the equiaxed nanoscale α-Al grains at sizes of 25~35nm and 20~35nm, respectively, acting as efficient heterogeneous nucleating agents to promote the formation of equiaxed nanoscale α-Al grains. Meanwhile, Al2CuMg, Mg2Si and Al5Mo nanoscale particles (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.

[0074] The apparatus and laser scanning strategy for preparing heterogeneous multiphase nanoparticle-reinforced aluminum-based alloys by laser powder bed melting in Examples 1-3 can be found in [reference needed]. Figure 2 .

[0075] In summary, this invention addresses the limitations of existing AlMgErZr alloys in terms of strength, thermal stability, and wear resistance by innovatively introducing copper (Cu), niobium (Nb), and molybdenum disilicide (MoSi2). During laser powder bed melting, Cu and Nb form Al2CuMg and Al3Nb nanoparticles, respectively. MoSi2 decomposes in situ into Mo and Si during laser powder bed melting, which interact with Al and Mg elements to generate Al5Mo and Mg2Si nanoparticles, respectively. Al3(Er,Zr) is also formed in situ during laser powder bed melting. The intragranular Al3(Er,Zr) and Al3Nb nanoparticles act as highly efficient heterogeneous nucleating agents, significantly refining the grain size. The Al2CuMg, Mg2Si, and Al5Mo nanoparticles at the grain boundaries, together with the α-Al matrix, constitute a unique soft (α-Al matrix) / hard (intermetallic compound particles) heterostructure, which synergistically enhances strength through heterogeneous deformation-induced strengthening, dislocation pinning, and load transfer. Intracrystalline nanoparticles stabilize the crystal structure by hindering dislocation climb, while hard nanoparticles at grain boundaries enhance thermal stability by suppressing high-temperature grain boundary migration and grain coarsening through pinning. Simultaneously, they act as a high-hardness barrier to directly resist wear and improve wear resistance. This synergistic design of "intracrystalline nanorefinement + grain boundary multiphase dispersion" provides a new approach for preparing high-performance aluminum-based materials.

[0076] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A laser-bonded powder bed melting heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloy, characterized in that, The laser-fused powder bed fusion heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloy is composed of equiaxed nanoscale α-Al grains. Nanoscale hard phase particles are dispersed at the grain boundaries of the equiaxed nanoscale α-Al grains, and nanoscale Al3(Er,Zr) particles and nanoscale Al3Nb particles are distributed within the grains. The nanoscale Al3(Er,Zr) particles and nanoscale Al3Nb particles are located within the grains of different equiaxed nanoscale α-Al grains. The soft α-Al matrix composed of equiaxed nanoscale α-Al grains and the nanoscale hard phase particles together form a unique soft / hard heterostructure. The nanoscale hard phase particles include nanoscale Al2CuMg particles, nanoscale Mg2Si particles, and nanoscale Al5Mo particles.

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

3. The laser-bonded powder bed melting heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloy according to any one of claims 1 to 2, characterized in that, The laser-fused powder bed heterogeneous multiphase nanoparticle synergistic reinforced aluminum-based alloy, after aging treatment, exhibits a yield strength of 560–660 MPa, a tensile strength of 620–850 MPa, and an elongation of 6–15%; its softening temperature is increased to 525–550 °C; and its wear rate is 0.808 × 10⁻⁶. -3 ~1.616×10 -3 mm 3 / (N·m).

4. A method for synergistic reinforcement of aluminum-based alloys using laser powder bed melting of heterogeneous multiphase nanoparticles, characterized in that, Includes the following steps: S1: The aluminum-based alloy composite powder is uniformly mixed using a mechanical powder mixer and then subjected to vacuum drying. The chemical composition of the aluminum-based alloy composite powder is: 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.%, MoSi2 0.2~3 wt.%, with the balance being Al. The particle size of the aluminum-based alloy composite powder is 15~53 μm, and the powder purity is higher than 99.9%. S2: Establish a 3D model and perform layered slicing. Based on the slice contour information, generate a series of laser selective melting and forming primary melting scanning trajectories and in-situ high-speed secondary melting scanning trajectories. S3: Pour the dried composite powder into the powder chamber of the printer, fix the substrate on the forming platform, close the chamber door, and then turn on the fan to introduce argon gas so that the oxygen content in the sealed chamber reaches the set value. S4: Spread powder and use laser for initial melting; S5: In-situ high-speed secondary melting using laser; S6: Repeat steps S4 and S5 until the printing of the heterogeneous multiphase nanoparticle synergistic reinforcement aluminum-based alloy is completed; S7: The printed heterogeneous multiphase nanoparticle synergistic reinforced aluminum-based alloy is heat-treated to promote the precipitation of multiphase nanoparticles and obtain the laser powder bed fusion heterogeneous multiphase nanoparticle synergistic reinforced aluminum-based alloy as described in any one of claims 1 to 3.

5. The method according to claim 4, characterized in that, The process parameters for the initial melting in step S4 are as follows: 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 rotation angle of interlayer laser scanning direction of 67°.

6. The method according to claim 4, characterized in that, The in-situ high-speed secondary melting process parameters in step S5 are as follows: laser power is 200~1000W, laser scanning rate is 3000~8000mm / s, laser spot diameter is 100μm, scanning spacing is 50~80μm, powder layer thickness is 25~30μm, and the rotation angle of the interlayer laser scanning direction is 67°.

7. The method according to claim 4, characterized in that, The heat treatment in step S7 is as follows: aging treatment at 250~500°C for 2~6 hours, followed by air cooling.

8. The method according to any one of claims 4 to 7, characterized in that, The substrate is an aluminum alloy, and the oxygen content is set at 200~1000ppm.

9. A method for applying laser powder bed melting heterogeneous multiphase nanoparticles synergistically reinforcing aluminum-based alloys, characterized in that, Applications of laser-bonded powder bed fusion heterogeneous multiphase nanoparticle synergistic reinforced aluminum-based alloys according to any one of claims 1 to 3 or prepared by the method according to any one of claims 4 to 8 in the fields of rail transit, new energy vehicles and aerospace technology.

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