Laser Hybrid Additive Manufacturing Method and Application of Lightweight Heat-Resistant High-Strength Aluminum Matrix Composites

Abstract

The present invention discloses a laser composite additive manufacturing method and application for lightweight, heat-resistant, high-strength aluminum-based composite materials. The method comprises: extracting oxygen from a sealed printing chamber and introducing argon to balance the pressure difference between the inside and outside of the printing chamber; coupling the laser beams output by a pulsed fiber laser and a continuous fiber laser, and adjusting the coupled laser beam; using the adjusted focused coupled laser beam to selectively melt aluminum-based composite powder on a substrate; after the printed aluminum-based composite material single layer cools and solidifies, laying TiB2 powder on its surface, and covering the TiB2 powder with transparent quartz glass, then using a pulsed laser to defocus and irradiate the TiB2 powder through the quartz glass to generate a high-explosive plasma; and utilizing the thermal-mechanical coupling effect of selective melting of the coupled laser beam and defocused pulsed laser shock strengthening to alternate layer by layer, in sequence. The present invention combines coupled laser with a single pulse laser to produce a lightweight, heat-resistant, high-strength aluminum-based composite material.

Description

Technical Field

[0001] The present invention belongs to the fields of laser additive manufacturing technology and metal composite material preparation technology, and in particular relates to a laser composite additive manufacturing method and application of a lightweight, heat-resistant, high-strength aluminum-based composite material. Background Art

[0002] With the continuous development of cutting-edge industries such as aerospace, the demand for improved high-temperature strength and heat resistance of metal structural parts has become increasingly urgent. Against this backdrop, ceramic particle-reinforced aluminum matrix composites (AMCs) have become a hot topic, offering excellent properties such as lightweight, high specific strength and stiffness, excellent thermal stability, and superior wear and corrosion resistance. Titanium diboride (TiB2) particles, as an ideal thermally stable dispersion-strengthened phase material, possess high melting point, high strength, excellent chemical stability, and good compatibility with the aluminum matrix. MoSi2 reacts with aluminum alloys at high temperatures to form a high-temperature oxidation film, while HfO2 purifies the grain boundaries of the aluminum alloy matrix, improving its high-temperature cracking resistance. These TiB2, MoSi2, and HfO2 particles have become key research targets.

[0003] However, improving the strength and heat resistance of the above-mentioned particle-reinforced aluminum-based composites faces a series of challenges, mainly due to the fact that nano-sized particles have the best dispersion strengthening effect on aluminum-based composites, but are difficult to prepare. Existing research has mainly focused on improving the preparation process, including stirring and casting, powder metallurgy, and additive manufacturing technology. These methods have certain limitations in the dispersion, morphology, and size of the reinforcing particles, which affects the performance of the composites. In the stirring and casting method, the agglomeration of nanoparticles, the stress concentration caused by the irregular shape of the particles, and the introduction of gas and impurities become restrictive factors. Although the powder metallurgy method can achieve uniform dispersion of nanoparticles, it is expensive and difficult to carry out industrial production. In the single continuous laser selective melting forming process, since the melting point of TiB2, MoSi2, and HfO2 particles is much higher than that of the aluminum matrix material, increasing the energy density of the high-energy beam continuous laser will only increase the melting of the aluminum matrix and expand the molten pool area, but cannot change the morphology of the TiB2, MoSi2, and HfO2 reinforcement particles. Most of the reinforcement particles always exist in the molten pool in the original solid non-nanoscale powder particle form, and nano-sized particles cannot be obtained, resulting in poor dispersion strengthening effect. Summary of the Invention

[0004] In order to address the deficiencies of the above-mentioned prior art, the present invention provides a laser composite additive manufacturing method and application of lightweight, heat-resistant, high-strength aluminum-based composite materials, which utilizes continuous and high-peak intensity pulsed dual laser coupling scanning to prepare aluminum alloy block layers with nano-sized TiB2, TiB, MoSi2 and HfO2 particle dispersion strengthening, and then utilizes the impact strengthening and large plastic deformation effect of high-peak intensity pulsed laser to eliminate the internal stress and metallurgical defects of the block layer layer by layer, thereby preparing a lightweight, high-strength, heat-resistant, high-performance aluminum-based composite material with fine-grained structure.

[0005] The first object of the present invention is to provide a laser composite additive manufacturing method for lightweight, heat-resistant, and high-strength aluminum-based composite materials.

[0006] The second object of the present invention is to provide a lightweight, heat-resistant, high-strength aluminum-based composite material.

[0007] The third object of the present invention is to provide an application of a lightweight, heat-resistant, high-strength aluminum-based composite material.

[0008] The first object of the present invention can be achieved by adopting the following technical solutions:

[0009] A laser composite additive manufacturing method for a lightweight, heat-resistant, high-strength aluminum-based composite material, the method comprising:

[0010] The oxygen in the printing chamber is extracted and argon is introduced to balance the pressure difference between the inside and outside of the printing chamber;

[0011] The laser beams output by the pulsed fiber laser and the continuous fiber laser are coupled, and the coupled laser beams are adjusted to ensure the consistency of the laser beam focus spot size and energy density on the substrate. According to the generated two-dimensional scanning trajectory, the adjusted focused coupled laser beam is used to selectively melt the aluminum-based composite powder and print it in lanes and layers on the preheated substrate. The aluminum-based composite powder is micron TiB2, MoSi2, and HfO2 particles dispersed in AlSi10Mg powder, and their mass ratios are 5-8wt.%, 10-20 ... 3~5wt.%, 1~2wt.% and 85~91wt.%; the process parameters of the adjusted focused coupled laser beam selective melting are: scanning speed of 1000~2000mm / s, overlap rate of 20~50%, layer thickness of 20~30μm, and coupling laser rotation angle of 67° or 90° during interlayer scanning. The pulsed laser induces the precipitation of high-melting-point TiB2, MoSi2, and HfO2 micron particles in various ways to form nano-sized TiB2, TiB, MoSi2 and HfO2 reinforcement particles;

[0012] After a single layer of aluminum-based composite material to be printed cools and solidifies, a layer of TiB2 powder is laid on its surface and a transparent quartz glass is pressed on the TiB2 powder. A single high-peak intensity pulsed laser is then used to defocus and irradiate the TiB2 powder through the quartz glass to generate a high-explosive plasma. This allows the printed single layer of composite material to undergo the large plastic deformation effect of the defocused single pulse laser shock strengthening, thereby eliminating internal stress and metallurgical defects. The process parameters for the defocused single pulse laser shock strengthening are: a pulse repetition frequency of 1 Hz to 10 kHz, a scanning speed of 1 to 100 mm / s, an overlap ratio of 20 to 50%, and a layer thickness of 15 to 20 μm.

[0013] The thermal-mechanical coupling effect of the adjusted focused coupled laser beam selective melting and the defocused single high-peak intensity pulse laser shock strengthening is used to interact layer by layer, in sequence, until the size of the prepared lightweight, heat-resistant, and high-strength aluminum-based composite material meets the requirements.

[0014] Furthermore, when the adjusted focused coupled laser beam is used for selective melting, the laser beams output by the pulsed fiber laser and the continuous fiber laser are coupled through the optical fiber. The setting parameters of the pulsed fiber laser are: central wavelength of 1064nm, laser power of 10 to 100W, peak pulse width of 1 to 100ns, pulse repetition frequency of 1kHz, and focused spot diameter of 25μm; the setting parameters of the continuous fiber laser are: central wavelength of 1064nm, laser power of 100 to 500W, maximum modulation frequency of 100kHz, and focused spot diameter of 50μm.

[0015] Furthermore, when a defocused single pulse laser is used for shock peening, the setting parameters of the pulse fiber laser are: central wavelength of 1064nm, laser power of 10-100W, pulse repetition frequency of 1Hz-10kHz, and defocused laser spot diameter of 800-1200μm.

[0016] Furthermore, the aluminum-based composite powder is obtained by the following method:

[0017] TiB2, MoSi2, HfO2 micron particles and titanium alloy powder in a set proportion are mixed, and then the mixed powder is mechanically ball-milled at room temperature under an argon protective atmosphere to disperse the TiB2, MoSi2, HfO2 micron particles in the titanium alloy powder; the mixed powder after room temperature mechanical ball milling is subjected to low-temperature mechanical ball milling in liquid nitrogen to obtain ultrafine near-spherical aluminum-based composite powder that meets the requirements for laser selective melting forming, and finally vacuum drying is performed.

[0018] Furthermore, the average particle size of micron TiB2, MoSi2, and HfO2 is 1~3μm, and the average particle size of aluminum-based alloy powder is 15~53μm.

[0019] Furthermore, the chemical composition of the micron TiB2 particle powder is (wt.%): B ≥30.0%, O ≤1.0%, C ≤0.1%, and the balance is Ti; the chemical composition of the micron MoSi2 particle powder is (wt.%): Si ≥36.0%, O ≤0.15%, C ≤0.03%, and the balance is Mo; the chemical composition of the micron HfO2 particle powder is (wt.%): O ≥15.0%, S ≤1.0%, and the balance is Hf; the chemical composition of the AlSi10Mg powder is (wt.%): Si 9.0~11.0%, Mg 0.2~0.45%, Fe ≤0.55%, Mn ≤0.45%, Zn ≤0.1%, and the balance is Al.

[0020] Furthermore, in lightweight, heat-resistant, and high-strength aluminum-based composite materials, TiB2 and TiB are uniformly dispersed in the refined aluminum matrix in the form of nano-sized spherical particles, which refines the aluminum matrix grains to form a fine-grain strengthening effect, which is beneficial to the dispersion strengthening effect of TiB2 and TiB; nano-sized MoSi2 and HfO2 are both dispersed at the grain boundaries of α-Al, and nano-MoSi2 will react with Al under high temperature conditions to form an excellent high-temperature resistant protective film, and nano-HfO2 can significantly purify the grain boundaries to improve its crack resistance.

[0021] Furthermore, the average particle size of the nano-sized TiB2, TiB, MoSi2 and HfO2 reinforcement particles is 300 to 800 nm.

[0022] The second object of the present invention can be achieved by adopting the following technical solutions:

[0023] A lightweight, heat-resistant, high-strength aluminum-based composite material is prepared based on the above-mentioned laser composite additive manufacturing method.

[0024] The third object of the present invention can be achieved by adopting the following technical solutions:

[0025] An application of a lightweight, heat-resistant, high-strength aluminum-based composite material, and the application of the lightweight, heat-resistant, high-strength aluminum-based composite material prepared by the above-mentioned laser composite additive manufacturing method in the fields of aerospace, rail transportation, and electronic industry technology.

[0026] The present invention has the following beneficial effects compared to the prior art:

[0027] 1. Compared with the single laser technology that only relies on heat input characteristics for selective melting using continuous laser, when the high melting point TiB2, MoSi2, HfO2 reinforcement phase and aluminum matrix composite powder with large differences in thermal properties are selectively melted, the above reinforcement phase always exists in the aluminum liquid matrix in solid form and does not undergo physical state transformation, and the aluminum-based material has high reflectivity, so nano-sized particles cannot be obtained; the present invention first uses continuous / pulse dual laser coupling to print aluminum-based material composite powder with dispersed distribution of ultrafine TiB2, MoSi2, HfO2 particles, and uses continuous / pulse composite laser to induce extraordinary composite effects such as material thermal deposition, plasma excitation activation and compressive stress shock wave to cause TiB2, MoSi2, HfO2 to undergo physical state transformation. , transforming from micron-sized particles into solid state into plasma and liquid phase with multiple physical components coexisting in the aluminum liquid matrix. During the rapid solidification process, a large number of nano-sized TiB2, TiB, MoSi2 and HfO2 strengthening phase particles will be precipitated in various ways such as electrolytic precipitation, solid solution precipitation, and secondary precipitation. The interface bonding strength between the strengthening phase and the aluminum matrix is high. After the dual laser scanning forming layer is cooled and solidified, a layer of TiB2 powder is laid on its surface and covered with transparent quartz glass. A single high-peak intensity pulsed laser is continued to be used to irradiate the newly laid TiB2 powder through the quartz glass to form a high-explosive plasma, so that the dual laser coupled scanning forming layer is subjected to the impact strengthening large plastic deformation effect generated by the single pulse laser to eliminate the internal stress and metallurgical defects of the block layer.

[0028] 2. In the aluminum-based composite material prepared by the present invention, TiB2 and TiB are uniformly dispersed in the refined aluminum matrix in the form of nano-sized spherical particles, so as to refine the aluminum matrix grains and form a fine-grain strengthening effect, which is beneficial for TiB2 and TiB to better play the role of dispersion strengthening and improve the mechanical properties of the material; and nano-TiB2 and TiB are firmly bonded to the aluminum matrix, and there is no adverse reaction at the interface; nano-sized MoSi2 and HfO2 are both dispersed at the grain boundaries of α-Al, and nano-MoSi2 will react with Al under high temperature conditions to form an excellent high-temperature resistant protective film, and nano-HfO2 can significantly purify the grain boundaries to improve its crack resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] 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.

[0030] Figure 1Schematic diagram of a dual-laser coupled selective melting process for forming nanoparticle (TiB2 as an example) dispersion-reinforced aluminum-based composite material according to an embodiment of the present invention;

[0031] Figure 2 This is a scanning electron microscope image of an aluminum-based material composite powder with dispersed ultrafine particles (taking TiB2 as an example) according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] 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 embodiments described are part of the embodiments of the present invention, not all of them. 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 the present application and are not used to limit the scope of the present application.

[0033] Example:

[0034] The laser composite additive manufacturing method for lightweight, heat-resistant, high-strength aluminum-based composite materials provided in this embodiment can be referred to Figure 1 , specifically including the following steps:

[0035] (1) Preparation of aluminum-based composite powder.

[0036] The original purity of TiB2 powder, MoSi2 powder and HfO2 powder is above 99.5%, and the average particle size is 1μm~3μm; the purity of aluminum-based powder is above 99.5%, and the average particle size is 15μm~53μm. Among them, the chemical composition of TiB2 particle powder is (wt.%): B ≥ 30.0%, O ≤ 1.0%, C ≤ 0.1%, and the balance is Ti; the chemical composition of MoSi2 particle powder is (wt.%): Si ≥ 36.0%, O ≤ 0.15%, C ≤ 0.03%, and the balance is Mo; the chemical composition of HfO2 particle powder is (wt.%): O ≥ 15.0%, S ≤ 1.0%, and the balance is Hf; the aluminum-based powder is AlSi10Mg powder, and its chemical composition is (wt.%): Si 9.0~11.0%, Mg 0.2~0.45%, Fe ≤ 0.55%, Mn ≤ 0.45%, Zn ≤ 0.1%, and the balance is Al.

[0037] In this embodiment, the TiB2 powder, MoSi2 powder, and HfO2 powder selected have an initial purity of 99.5% or higher, and an average particle size of 3 μm. The aluminum-based powder has a purity of 99.5% or higher, and an average particle size of 15 μm. The chemical composition of the TiB2 granular powder is (wt.%): 30.0% B, 1.0% O, 0.1% C, and the balance Ti. The chemical composition of the MoSi2 granular powder is (wt.%): 36.0% Si, 0.15% O, 0.03% C, and the balance Mo. The chemical composition of the HfO2 granular powder is (wt.%): 15.0% O, 1.0% S, and the balance Hf. The aluminum-based powder is AlSi10Mg powder, whose chemical composition is (wt.%): 10.0% Si, 0.30% Mg, 0.55% Fe, 0.45% Mn, 0.10% Zn, and the balance Al.

[0038] A mixed powder consisting of 5~8wt.% TiB2 powder, 3~5wt.% MoSi2 powder, 1~2wt.% HfO2 powder and 85~91wt.% AlSi10Mg powder was mixed for 240 minutes using a powder mixer at a mixing speed of 12rpm. After being taken out, it was dried to obtain an aluminum-based composite powder with dispersed ultrafine TiB2, MoSi2 and HfO2 particles.

[0039] The mass ratio of TiB2 powder, MoSi2 powder, HfO2 powder and AlSi10Mg powder selected in this embodiment is 5:3:2:90.

[0040] The scanning electron microscopy of the aluminum-based composite powder (using TiB2 as an example) prepared in this embodiment can be referred to Figure 2 , TiB2 powder and AlSi10Mg powder are mixed evenly without a large amount of agglomeration.

[0041] (2) A three-dimensional model is established based on the lightweight, heat-resistant, high-strength aluminum-based composite material to be prepared and layered slicing is performed. A series of two-dimensional scanning trajectories for laser selective melting are generated based on the slice contour information.

[0042] (3) According to the generated two-dimensional scanning trajectory, dual laser coupling selective melting is used to print the aluminum-based composite powder in lanes and layers on the substrate.

[0043] Specifically, aluminum-based composite powder was loaded into the hopper of an automatic powder feeder. Before the experiment, the printing chamber was cleaned and the substrate plane was adjusted. The chamber was evacuated to a vacuum, reducing the oxygen content to less than 1000 ppm. Argon was then filled to balance the pressure difference between the inside and outside of the chamber. In this example, the residual oxygen content in the chamber was 100 ppm.

[0044] The process parameters of dual laser coupled selective melting in this embodiment are: the scanning speed of the coupled laser beam is 1500 mm / s, the overlap rate is 50%, the layer thickness is 20 μm, the coupled laser rotation angle is 90° during interlayer scanning, and the high melting point TiB2, MoSi2, and HfO2 micron particles are induced by pulse laser to precipitate in various ways to form nano-sized TiB2, TiB, MoSi2, and HfO2 enhanced particles. Among them, the parameters of the pulsed fiber laser are: wavelength of 1064 nm, laser power of 50 W, pulse width of 10 ns, pulse repetition frequency of 1 kHz, and focused spot diameter of 25 μm; the parameters of the continuous fiber laser are: wavelength of 1064 nm, laser power of 300 W, focused spot diameter of 50 μm, modulation frequency of 100 kHz; the composite laser energy density is 78.24 J / mm 3 .

[0045] (4) After the coupled laser scanning forming layer cools and solidifies, another layer of TiB2 powder is laid on its surface and covered with translucent quartz glass. A single high-peak intensity pulsed laser is used to irradiate the newly laid TiB2 powder through the quartz glass to form a high-explosive plasma, which produces a shock-hardening large plastic deformation effect. The shock-hardening large plastic deformation effect of the high-peak intensity pulsed laser is used to eliminate the internal stress and metallurgical defects of the block layer layer by layer. The thermal-mechanical coupling effect of dual laser coupled selective melting and single pulse laser shock hardening is repeated layer by layer, and finally a lightweight, heat-resistant, high-strength aluminum-based composite material with a fine-grained structure is obtained.

[0046] The process parameters of high peak intensity pulsed laser shock peening in this embodiment are: the defocused laser spot diameter is 1000 μm, the pulse repetition frequency is 100 Hz, the scanning speed is 10 mm / s, the overlap rate is 25%, and the layer thickness is 20 μm.

[0047] The microstructure characterization and mechanical properties analysis of lightweight, heat-resistant, high-strength aluminum-based composite materials led to the following conclusions:

[0048] Scanning electron microscopy (SEM) was used to characterize the microstructure and investigate the typical microstructure. SEM images of cladding layers prepared with TiB2, MoSi2, and HfO2 on AlSi10Mg and native AlSi10Mg alloy were analyzed. The results show that the native AlSi10Mg alloy exhibits a columnar unit cell morphology. In contrast, the AlSi10Mg alloy reinforced with TiB2, MoSi2, and HfO2 particles exhibits uniform ultrafine equiaxed crystals with no apparent orientation. Aggregates of nanoparticles can be observed at the common vertices of multiple unit cells. Furthermore, electron backscattered scattering (EBSD) was used to determine grain size and area. Magnified images of the samples revealed a large number of nanostructured particles exhibiting a cubic prism-like morphology with particle sizes less than 500 nm. In the TiB2, MoSi2, and HfO2 particle-reinforced AlSi10Mg alloy, approximately 40% of the grains are smaller than 1 μm, with an average diameter of approximately 2.1 μm.

[0049] Mechanical properties were analyzed using dog-bone tensile test specimens machined according to ASTM-E8M standards and tested on a Zwick / Roell Z100 testing machine. Tensile tests were conducted on samples of AlSi10Mg alloy reinforced with TiB2, MoSi2, and HfO2 particles, as well as on native AlSi10Mg alloy samples. Specifically, the native AlSi10Mg alloy exhibited a room-temperature tensile strength of approximately 490 MPa and an elongation of 3.7%. The room-temperature tensile strength and elongation of the AlSi10Mg reinforced with TiB2, MoSi2, and HfO2 were significantly enhanced, reaching 530 MPa and 8%, respectively, with a tensile strength of 155 MPa at 420°C. Therefore, the AlSi10Mg composite reinforced with TiB2, MoSi2, and HfO2 exhibited significant improvements in both tensile strength and ductility, while also exhibiting excellent high-temperature strength resistance. Consequently, through the combined effects of grain refinement and solid solution strengthening, a lightweight, high-strength, and heat-resistant aluminum-based composite with a fine-grained structure was formed.

[0050] The microstructural characteristics of the lightweight, heat-resistant, high-strength aluminum-based composite material prepared in this embodiment are as follows: the metal matrix is composed of fine equiaxed crystals, approximately 40% of the grains are less than 1 μm in size, and the average diameter is about 2.1 μm; due to a series of nonlinear effects generated by the combined action of the dual lasers, nanoparticles are precipitated in various ways such as electrochemical precipitation, solid solution precipitation, and secondary precipitation, and nano-sized TiB2, TiB, MoSi2, and HfO2 particles are evenly distributed at the grain boundaries of the metal matrix.

[0051] In summary, the present invention adopts prefabricated aluminum-based composite powder with dispersed ultrafine TiB2, MoSi2, and HfO2 particles, and utilizes the thermal deposition, photo-induced plasma excitation activation, and compressive stress shock wave extraordinary composite effects under the composite action of high peak intensity pulse / continuous dual laser to rapidly heat the composite powder to a high temperature, so that TiB2, MoSi2, and HfO2 coexist in the aluminum liquid matrix in the form of plasma and liquid phase. Nano-sized TiB2, MoSi2, TiB, and HfO2 particles are precipitated during the rapid solidification process. After the dual laser coupling scanning forming layer is cooled and solidified, the surface is re-molded. A layer of TiB2 powder is laid and covered with translucent quartz glass. A single high-peak intensity pulsed laser is then used to irradiate the newly laid TiB2 powder through the quartz glass to form a high-explosive plasma, so that the dual-laser coupled scanning forming layer is then subjected to the large plastic deformation effect of the impact strengthening generated by the single pulsed laser. The large plastic deformation effect of the impact strengthening of the high-peak intensity pulsed laser is utilized to eliminate the internal stress and metallurgical defects of the block layer layer by layer. The thermal-mechanical coupling effect of the dual-laser coupled selective melting and the pulsed single laser shock strengthening interacts layer by layer, and reciprocates in sequence, ultimately preparing a lightweight, high-strength, heat-resistant, and high-strength aluminum-based composite material with a fine-grained microstructure. The present invention is expected to provide solutions with academic value and practical application prospects for important industrial fields such as aerospace in terms of solving technical problems, optimizing process parameters, and establishing new systems and preparation methods.

[0052] 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 composite additive manufacturing method for lightweight, heat-resistant, high-strength aluminum-based composite materials, characterized in that: The method comprises: The oxygen in the printing chamber is extracted and argon is introduced to balance the pressure difference between the inside and outside of the printing chamber; The laser beams output by the pulsed fiber laser and the continuous fiber laser are coupled, and the coupled laser beams are adjusted to ensure the consistency of the laser beam focus spot size and energy density on the substrate. According to the generated two-dimensional scanning trajectory, the adjusted focused coupled laser beam is used to selectively melt the aluminum-based composite powder and print it in lanes and layers on the preheated substrate. The aluminum-based composite powder is micron TiB2, MoSi2, and HfO2 particles dispersed in AlSi10Mg powder, and their mass ratios are 5-8wt.%, 10-20 ... 3~5wt.%, 1~2wt.% and 85~91wt.%; the process parameters of the adjusted focused coupled laser beam selective melting are: scanning speed of 1000~2000mm / s, overlap rate of 20~50%, layer thickness of 20~30μm, and coupling laser rotation angle of 67° or 90° during interlayer scanning. The pulsed laser induces the precipitation of high-melting-point TiB2, MoSi2, and HfO2 micron particles in various ways to form nano-sized TiB2, TiB, MoSi2 and HfO2 reinforcement particles; After a single layer of aluminum-based composite material to be printed cools and solidifies, a layer of TiB2 powder is laid on its surface and a transparent quartz glass is pressed on the TiB2 powder. A single high-peak intensity pulsed laser is then used to defocus and irradiate the TiB2 powder through the quartz glass to generate a high-explosive plasma. This allows the printed single layer of composite material to undergo the large plastic deformation effect of the defocused single pulse laser shock strengthening, thereby eliminating internal stress and metallurgical defects. The process parameters for the defocused single pulse laser shock strengthening are: a pulse repetition frequency of 1 Hz to 10 kHz, a scanning speed of 1 to 100 mm / s, an overlap ratio of 20 to 50%, and a layer thickness of 15 to 20 μm. The thermal-mechanical coupling effect of the adjusted focused coupled laser beam selective melting and the defocused single high-peak intensity pulse laser shock strengthening is used to interact layer by layer, in sequence, until the size of the prepared lightweight, heat-resistant, and high-strength aluminum-based composite material meets the requirements.

2. The method according to claim 1, characterized in that When selective melting is performed using the adjusted focused coupled laser beam, the laser beams output by the pulsed fiber laser and the continuous fiber laser are coupled through the optical fiber. The setting parameters of the pulsed fiber laser are: central wavelength of 1064nm, laser power of 10 to 100W, peak pulse width of 1 to 100ns, pulse repetition frequency of 1kHz, and focused spot diameter of 25μm; the setting parameters of the continuous fiber laser are: central wavelength of 1064nm, laser power of 100 to 500W, maximum modulation frequency of 100kHz, and focused spot diameter of 50μm.

3. The method according to any one of claims 1 and 2, characterized in that: When a defocused single pulse laser is used for shock peening, the setting parameters of the pulse fiber laser are: central wavelength of 1064nm, laser power of 10-100W, pulse repetition frequency of 1Hz-10kHz, and defocused laser spot diameter of 800-1200μm.

4. The method according to claim 1, wherein The aluminum-based composite powder is obtained by the following method: TiB2, MoSi2, HfO2 micron particles and titanium alloy powder in a set proportion are mixed, and then the mixed powder is mechanically ball-milled at room temperature under an argon protective atmosphere to disperse the TiB2, MoSi2, HfO2 micron particles in the titanium alloy powder; the mixed powder after room temperature mechanical ball milling is subjected to low-temperature mechanical ball milling in liquid nitrogen to obtain ultrafine near-spherical aluminum-based composite powder that meets the requirements for laser selective melting forming, and finally vacuum drying is performed.

5. The method according to any one of claims 1 and 4, characterized in that: The average particle size of micron TiB2, MoSi2, and HfO2 is 1~3μm, and the average particle size of aluminum-based alloy powder is 15~53μm.

6. The method according to any one of claims 1 and 4, characterized in that: The chemical composition of the micron TiB2 particle powder is (wt.%): B ≥30.0%, O ≤1.0%, C ≤0.1%, and the balance is Ti; the chemical composition of the micron MoSi2 particle powder is (wt.%): Si ≥36.0%, O ≤0.15%, C ≤0.03%, and the balance is Mo; the chemical composition of the micron HfO2 particle powder is (wt.%): O ≥15.0%, S ≤1.0%, and the balance is Hf; the chemical composition of the AlSi10Mg powder is (wt.%): Si 9.0~11.0%, Mg 0.2~0.45%, Fe ≤0.55%, Mn ≤0.45%, Zn ≤0.1%, and the balance is Al.

7. The method according to claim 1, characterized in that In lightweight, heat-resistant, high-strength aluminum-based composite materials, TiB2 and TiB are uniformly dispersed in the refined aluminum matrix as nano-sized spherical particles, forming a fine-grain strengthening effect by refining the aluminum matrix grains, which is conducive to the dispersion strengthening effect of TiB2 and TiB; nano-sized MoSi2 and HfO2 are both dispersed at the grain boundaries of α-Al, and nano-MoSi2 will react with Al under high temperature conditions to form an excellent high-temperature resistant protective film, and nano-HfO2 can significantly purify the grain boundaries to improve its crack resistance.

8. The method according to any one of claims 1 and 7, characterized in that: The average particle size of the nano-sized TiB2, TiB, MoSi2 and HfO2 reinforcement particles is 300 to 800 nm.

9. A lightweight, heat-resistant, high-strength aluminum-based composite material, characterized in that: It is prepared based on the laser composite additive manufacturing method according to any one of claims 1 to 8.

10. An application of a lightweight, heat-resistant, high-strength aluminum-based composite material, characterized in that: Application of the lightweight, heat-resistant, high-strength aluminum-based composite material prepared by the laser composite additive manufacturing method according to any one of claims 1 to 8 or the lightweight, heat-resistant, high-strength aluminum-based composite material according to claim 9 in the fields of aerospace, rail transportation, and electronic industry technology.

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