Method for preparing magnesium-based composite material based on semi-solid injection molding and product and application of magnesium-based composite material

Abstract

The invention discloses a method for preparing a magnesium-based composite material based on semi-solid injection molding and a product and application of the magnesium-based composite material, and belongs to the technical field of magnesium-based composite material preparation.The method comprises the following steps that a semi-solid injection molding method is adopted, a mixture of magnesium alloy matrix particles (millimeter-level) and high-entropy alloy powder is sequentially heated and stirred, and the magnesium alloy matrix particles (millimeter-level) and the high-entropy alloy powder are obtained; performing injection molding and cooling to obtain a sample; and the sample is annealed, and the magnesium-based composite material is prepared. Wherein the magnesium alloy matrix particles comprise the following components in percentage by mass: 1-9% of aluminum, 1-7% of zinc and the balance of magnesium and inevitable impurities (impurity elements are less than or equal to 0.1%); the high-entropy alloy powder is particles containing Al, Co, Cr, Fe and Ni elements, and the particle size is 0.5-50 microns. Magnesium alloy matrix particles and AlCoCrFeNi particles are mixed, and then a semi-solid injection molding technology is combined, so that the sedimentation problem of a high-density reinforced phase can be eliminated, the reinforced phase is uniformly dispersed in the material, and the comprehensive mechanical property of the composite material is further improved.

Description

Technical Field

[0001] This invention belongs to the field of magnesium-based composite material preparation technology, and particularly relates to a method for preparing magnesium-based composite materials based on semi-solid injection molding, as well as its products and applications. Background Technology

[0002] Magnesium-based composites, with their low density and high specific strength, have broad application prospects in aerospace and electronic equipment fields. Their research and application have been significantly promoted, especially against the backdrop of the rapid development of the new energy vehicle industry. Currently, ceramic particles such as SiC and Al2O3 are the most widely used reinforcing phases in magnesium-based composites. However, due to the brittleness of ceramic materials, SiC and Al2O3 often lead to a significant decrease in ductility while improving material strength. Compared with ceramic reinforcing phases, metallic reinforcing phases have higher toughness and the ability to coordinate matrix deformation, effectively preventing the initiation and propagation of cracks in composite materials, thus providing a feasible technical path for the synergistic improvement of material strength and toughness. However, because the density of AlCoCrFeNi high-entropy alloy is significantly higher than that of the magnesium matrix, traditional stir casting processes face the problem of particle sedimentation, leading to the aggregation of reinforcing phases within the material and making uniform dispersion difficult. This localized aggregation of reinforcing phases not only fails to improve the performance of the composite material but also becomes a weak area, impairing its overall performance. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention proposes a method for preparing magnesium-based composite materials based on semi-solid injection molding, along with its products and applications.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] One of the technical solutions of this invention:

[0006] A method for preparing magnesium-based composite materials based on semi-solid injection molding includes the following steps:

[0007] A semi-solid injection molding method was used to heat and stir a mixture of magnesium alloy matrix particles (millimeter-scale) and high-entropy alloy powder sequentially, followed by injection molding and cooling to obtain the sample.

[0008] The sample was annealed to prepare the magnesium-based composite material.

[0009] Of which, in terms of mass percentage,

[0010] The magnesium alloy matrix particles contain the following components: aluminum: 1% to 9%, zinc: 1% to 7%, with the balance being magnesium and unavoidable impurities (impurity elements ≤ 0.1%).

[0011] The high-entropy alloy powder is a particle containing Al, Co, Cr, Fe and Ni elements, with a particle size of 0.5 to 50 μm.

[0012] Beneficial Effects: This invention combines magnesium alloy matrix particles with AlCoCrFeNi particles. AlCoCrFeNi possesses high elastic modulus and yield strength, resulting in high load-bearing capacity during deformation, thus strengthening the composite material. Simultaneously, AlCoCrFeNi exhibits plastic deformation capability; its edge regions in contact with the matrix undergo plastic deformation due to high stress, coordinating matrix deformation and enhancing the composite material's plasticity. Furthermore, the Al element in AlCoCrFeNi helps improve the bonding between the particles and the matrix, thereby enhancing the composite material's overall mechanical properties. In addition, this invention provides an effective method for preparing magnesium-based composite materials using semi-solid injection molding technology. The working principle involves heating the metal to a semi-solid state, using a screw to stir and shear the semi-solid slurry, and then injecting it at high speed into a mold. This process solves the problem of sedimentation of the high-density reinforcing phase, enabling uniform dispersion of the reinforcing phase within the material and further improving the composite material's overall performance. The rapid solidification process of semi-solid injection results in a fine-grained structure, which is beneficial for increasing strength.

[0013] In addition, semi-solid injection molding has advantages in terms of energy efficiency and environmental friendliness, as its heating temperature is lower than that of traditional casting processes and it does not require the use of protective gas.

[0014] Optionally, the magnesium alloy matrix particles, in addition to magnesium and unavoidable impurities, have an aluminum mass fraction of 9% and a zinc mass fraction of 1%.

[0015] or,

[0016] The mass fraction of aluminum is 3%, and the mass fraction of zinc is 7%.

[0017] Beneficial effects: Both aluminum and zinc can lower the liquidus line of magnesium alloys, with aluminum having a more significant effect (e.g., the liquidus line of AZ61 is 610℃, and that of AZ91 is below 600℃). Lowering the liquidus line allows for reduced heating temperature and power, saving energy and reducing the material's oxidation tendency. The temperature range between the solidus and liquidus lines constitutes a semi-solid region, within which both solid and liquid phases exist simultaneously. A typical semi-solid region for AZ91 is 125℃. Increasing the zinc content expands this semi-solid region, broadening the process window for semi-solid injection molding. Given the good fluidity and filling capacity of high-aluminum magnesium matrices, aluminum in the matrix provides both solid solution and precipitation strengthening, increasing matrix strength. Zinc also provides both solid solution and precipitation strengthening; high-zinc magnesium matrices have lower strength than high-aluminum matrices but higher elongation. The magnesium alloy matrix particles with the above-described composition ratio, as defined in this invention, mixed with high-entropy alloy particles, can produce composite materials that combine strength and plasticity.

[0018] Optionally, in the magnesium-based composite material, the magnesium alloy matrix comprises 82–95 wt.% and the high-entropy alloy powder comprises 5–18 wt.%.

[0019] Furthermore, in the magnesium-based composite material, the high-entropy alloy powder accounts for 5.7 to 15.7 wt.%, with the balance being the magnesium alloy matrix.

[0020] Optionally, the high-entropy alloy powder contains 6%–43% Al atoms and 20%–35% Ni atoms; preferably Al3CoCrFeNi, AlCoCrFeNi, or AlCoCrFeNi. 2.1 .

[0021] Beneficial effects: The strength of high-entropy alloy powder is significantly higher than that of magnesium matrix, and its introduction can effectively improve the strength of the material; high-entropy alloy particles have plastic deformation ability, which can improve plasticity by coordinating matrix deformation; Al and Ni elements in high-entropy alloy particles can undergo interdiffusion and interfacial reaction with elements in magnesium alloy matrix to obtain composite materials with strong interfacial bonding.

[0022] Optionally, the heating process is carried out in the barrel in a segmented heating manner, with each segment having a temperature of 480 to 630°C and a heating time of 2 to 35 minutes.

[0023] Furthermore, during the segmented heating process:

[0024] The first stage heating temperature is 480℃; the heating time is 20 seconds to 5 minutes.

[0025] The second stage heating temperature is 550℃; the heating time is 20s to 5min.

[0026] The third stage heating temperature is 580℃; the heating time is 20 seconds to 5 minutes.

[0027] The fourth stage heating temperature is 600-625℃; the heating time is 20 seconds to 5 minutes.

[0028] The fifth stage heating temperature is 600-625℃; the heating time is 20 seconds to 5 minutes.

[0029] The sixth stage heating temperature is 605℃; the heating time is 20 seconds to 5 minutes.

[0030] The seventh stage heating temperature is 580℃; the heating time is 20s to 5min.

[0031] Optionally, the injection speed during the injection molding process is 1-5 m / s, the screw speed is 80-250 rpm, and the mold temperature is 200-350℃.

[0032] The cooling process takes 5-60 seconds.

[0033] Beneficial effects: The process parameters in the injection molding process defined by the present invention enable the screw shearing to effectively break dendrites, so that fine, equiaxed solid phases are uniformly distributed in the semi-solid slurry, and high-performance composite materials with fine grain size and uniform distribution of reinforcing phase in the matrix are prepared by rapid solidification.

[0034] Optionally, the annealing temperature during the annealing process is 150-300℃, and the time is 30 min-4 h.

[0035] Optionally, the method includes the following steps:

[0036] Magnesium alloy is melted, refined and purified and cast into ingots, and the ingots are cut into particles of millimeter size;

[0037] Mix magnesium alloy matrix particles with high-entropy alloy powder;

[0038] The particle-powder mixture is added to a semi-solid injection molding machine, the barrel is heated to form a semi-solid slurry, the slurry is mixed and stirred by the screw rotation, then injection molding is performed, and finally stress-relief annealing is carried out to obtain the magnesium-based composite material.

[0039] The second technical solution of this invention:

[0040] A magnesium-based composite material was prepared by the above method.

[0041] The third technical solution of this invention:

[0042] The above-mentioned magnesium-based composite materials are used in the preparation of lightweight structures and components.

[0043] Optionally, the lightweight structures and components include, but are not limited to, laptop shells, displays, electric vehicle wheel hubs, car steering wheels, engine lower cylinder blocks, integrated subframes, and new energy motor housings.

[0044] Compared with the prior art, the present invention has the following advantages and technical effects:

[0045] The high-entropy alloy-reinforced magnesium matrix composite material prepared by this invention has uniformly distributed reinforcing particles. By effectively utilizing the high toughness and deformability of metal particles, the composite material has both high strength and high plasticity, overcoming the shortcomings of poor plasticity in traditional ceramic particle-reinforced magnesium matrix composite materials.

[0046] The semi-solid injection molding technology used in this invention can be used for near-net-shape forming of high-entropy alloy particle-reinforced magnesium matrix composites, and has broad application potential in the aerospace, consumer electronics and automotive fields.

[0047] The high-entropy alloy-reinforced magnesium matrix composite material prepared by this invention exhibits a tight interfacial bond between the matrix and the high-entropy alloy particles. The interface is free of voids or coarse brittle phases, and a nanoscale reaction layer is formed at the interface, effectively improving interfacial bonding strength and load transfer efficiency. During loading, the high-entropy alloy particles effectively bear the load, enhancing the composite material's strength. Simultaneously, the high-entropy alloy particles coordinate matrix deformation through interfacial plastic deformation, providing localized hardening without causing cracking. Attached Figure Description

[0048] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0049] Figure 1 This is a microstructure image of the high-entropy alloy-reinforced magnesium-based composite material prepared in Example 1 of the present invention.

[0050] Figure 2 The energy spectrum of the microstructure of the high-entropy alloy-reinforced magnesium-based composite material prepared in Example 1 of this invention is shown.

[0051] Figure 3 This is a grain structure diagram of the high-entropy alloy-reinforced magnesium-based composite material prepared in Example 1 of the present invention;

[0052] Figure 4 This is a transmission electron micrograph of the interface region in the high-entropy alloy-reinforced magnesium matrix composite material prepared in Example 1 of the present invention. Detailed Implementation

[0053] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0054] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0055] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0056] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0057] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0058] This invention discloses a high-entropy alloy-reinforced magnesium-based composite material, which comprises the following raw materials by mass percentage:

[0059] The magnesium alloy matrix comprises 82-95% and the high-entropy alloy particles comprise 5-18%.

[0060] In the magnesium alloy matrix, aluminum is 1 wt.% to 9 wt.%, zinc is 1 wt.% to 7 wt.%, other impurity elements are ≤0.1%, and the remainder is magnesium. Hereinafter, magnesium-aluminum-zinc alloy will be abbreviated as AZ alloy, where the two digits after AZ represent the mass fraction of aluminum and zinc, respectively. For example, AZ91 is an alloy with 9% aluminum, 1% zinc, and the remainder magnesium.

[0061] In some alternative embodiments, the reinforcing high-entropy alloy particles in the magnesium-based composite material are AlCoCrFeNi particles, with a composition ranging from 6% to 43% aluminum atoms. A typical low-aluminum composition is Al. 0.3 CoCrFeNi, a typical high-aluminum composition is Al3CoCrFeNi; the nickel atom content is 20%–35%, with typical low-nickel compositions being AlCoCrFeNi and high-nickel compositions being AlCoCrFeNi. 2.1 ;

[0062] The particle size of the high-entropy alloy particles is 0.5–50 μm.

[0063] This invention also discloses a method for preparing the above-mentioned high-entropy alloy reinforced magnesium-based composite material, comprising the following steps:

[0064] Magnesium alloy is mixed according to its components, then melted, refined and purified, and cast into ingots to obtain magnesium alloy ingots.

[0065] Magnesium alloy ingots are cut into millimeter-sized particles and mixed with high-entropy alloy powder.

[0066] The raw material, which is a mixture of particles and powder, is fed from the barrel into a semi-solid injection molding machine. The segmented heating of the barrel section heats the magnesium alloy to a semi-solid state, while the AlCoCrFeNi particles remain solid. The heating temperature range is 480 to 630°C.

[0067] The semi-solid slurry is stirred by screw rotation, breaking down coarse dendrites and ensuring that equiaxed, uniform, and fine solid phases are evenly distributed in the slurry. The screw speed is >80 rpm. The stirring of the screw prevents AlCoCrFeNi particles from agglomerating and promotes their uniform distribution. In addition, the high viscosity of the semi-solid slurry prevents AlCoCrFeNi particles from settling.

[0068] The semi-solid slurry is injected into the mold at high speed to form samples and parts; finally, the material is subjected to stress-relief annealing to obtain the high-entropy alloy particle-reinforced magnesium matrix composite material.

[0069] Traditional methods for preparing magnesium-based composite materials using stir casting require heating to above the melting point of magnesium, resulting in high energy consumption and a tendency to introduce oxide inclusions, which reduces the mechanical properties of the material. This invention proposes a semi-solid injection molding method for preparing magnesium-based composite materials. This near-net-shape molding method integrates preparation, transport, and molding processes. The semi-solid slurry exhibits shear-thinning thixotropic properties, giving it good fluidity and facilitating better dispersion of reinforcing particles within the matrix.

[0070] Furthermore, in the process of preparing magnesium-based composite materials by semi-solid injection, the magnesium alloy is a semi-solid slurry, and the high-entropy alloy particles do not melt, becoming the nucleation points for solidification within the matrix. The rotation of the screw transports the mixed slurry to the nozzle and fully mixes the magnesium alloy matrix with the high-entropy alloy particles, resulting in a uniform distribution of high-entropy alloy particles within the matrix of the prepared composite material.

[0071] Furthermore, the semi-solid injection molding method used in this invention does not require metal melting equipment and has a low heating temperature, which greatly reduces energy consumption compared to die casting. Moreover, semi-solid injection does not require the greenhouse gas SF6 as a protective gas, making it safe and environmentally friendly; and it is highly efficient in producing samples and parts, with a cooling process requiring only 5-10 seconds.

[0072] Therefore, this invention refines the grain size of the composite material through the shearing effect of the screw rotation on the slurry and the high cooling rate of injection molding. The rotational shear force generated by the screw movement effectively breaks down dendrites, resulting in a uniform distribution of fine equiaxed primary phases in the slurry. During rapid solidification, this leads to the formation of near-spherical fine grains. The semi-solid injection-molded magnesium-based composite material has a grain size of <20μm and exhibits a significant grain-refining strengthening effect.

[0073] In an optional embodiment, the injection speed during the injection molding process is 1-5 m / s, and the mold temperature is 200-350°C.

[0074] In an optional embodiment, the annealing temperature during the stress-relief annealing process is 150–300°C.

[0075] Unless otherwise specified, "room temperature" in this invention refers to 20-30℃.

[0076] All raw materials used in this invention were purchased from the market.

[0077] The technical solution of the present invention will be further illustrated by the following embodiments.

[0078] Example 1

[0079] A method for preparing a high-entropy alloy-reinforced magnesium-based composite material includes the following steps:

[0080] (1) Weigh the raw materials for later use: The matrix material is AZ91 magnesium alloy, and the mass percentage of the matrix magnesium alloy (i.e., magnesium matrix) is 94.3%; the mass percentage of AlCoCrFeNi (atomic ratio of 1:1:1:1:1) high entropy alloy particles is 5.7%.

[0081] (2) The AZ91 magnesium alloy ingot was granulated using machining equipment to obtain magnesium matrix particles with a particle size of approximately 1.2×1.2×4mm.

[0082] Magnesium matrix particles and high-entropy alloy powder are mixed using the reciprocating motion and rotation of a three-dimensional mixer as raw materials for semi-solid injection.

[0083] (3) The mixed raw materials are added to the semi-solid injection molding machine through the hopper. The barrel section is heated in seven stages, with temperatures from the far end to the nozzle being 480℃, 550℃, 580℃, 615℃, 615℃, 605℃ and 580℃ respectively. The screw rotates continuously at a speed of 120 rpm to shear the semi-solid slurry, break up coarse dendrites, and make the fine equiaxed primary phase evenly distributed in the liquid phase. The semi-solid slurry is injected into the mold at a speed of 2.8 m / s (the temperature of the mold is 300℃), and the cooling time is 5 seconds.

[0084] (4) The semi-solid injection molded sample was subjected to stress-relief annealing (annealing temperature was 250℃, time was 2 hours) to prepare high-entropy alloy particle reinforced magnesium matrix composite material.

[0085] Figure 1 The image shows the microstructure of the high-entropy alloy-reinforced magnesium-based composite material prepared in Example 1 of this invention. As can be seen from the image, the high-entropy particles are uniformly distributed in the matrix of the magnesium-based composite material prepared in Example 1.

[0086] Figure 2 The energy dispersive spectroscopy (EDS) results for the microstructure of the high-entropy alloy-reinforced magnesium-based composite material prepared in Example 1 of this invention are shown below; Figure 2 The surface scan results show that the high-entropy reinforced particles contain Al, Co, Cr, Fe and Ni elements;

[0087] Figure 3 The grain structure results of the high-entropy alloy-reinforced magnesium-based composite material prepared in Example 1 of this invention; from Figure 3 Electron backscatter diffraction results of the grain structure show that the composite material has fine grains;

[0088] Figure 4 The image shows the transmission electron microscope observation results of the interface region in the high-entropy alloy-reinforced magnesium matrix composite material prepared in Example 1 of the present invention. As can be seen from the figure, the matrix and the reinforcing particles have good interfacial bonding, and a nanoscale interfacial reaction layer is generated.

[0089] Example 2

[0090] Same as Example 1, except that the mass fraction of high-entropy reinforced particles AlCoCrFeNi is increased to 15%; and the maximum heating temperature of the barrel is increased to 625°C.

[0091] Example 3

[0092] Same as Example 1, except that the magnesium matrix is ​​AZ37 alloy (3% aluminum by mass, 7% zinc by mass), and the high-entropy reinforcing particles AlCoCrFeNi by mass are 7%.

[0093] Example 4

[0094] Same as Example 1, except that the high-entropy alloy particles are Al3CoCrFeNi.

[0095] Example 5

[0096] Same as Example 1, except that the high-entropy alloy particles are AlCoCrFeNi. 2.1 .

[0097] Comparative Example 1

[0098] Same as Example 1, except that AlCoCrFeNi reinforcing particles are not added; the maximum heating temperature of the barrel is reduced to 610°C.

[0099] Comparative Example 2

[0100] Same as Example 1, except that the magnesium matrix uses AZ17 alloy (1% aluminum and 7% zinc by mass); the mass fraction of high-entropy alloy particles is increased to 25%; and the maximum heating temperature of the barrel is increased to 625°C.

[0101] Effect verification

[0102] The mechanical properties (quasi-static room temperature tensile properties test, test standard GB / T 228.1-2021) of the high-entropy alloy particle reinforced magnesium matrix composites prepared in the embodiments and comparative examples of the present invention were determined, and the results are shown in Table 1.

[0103] Table 1 Mechanical Properties

[0104]

[0105] The mechanical properties in Table 1 show that the high-entropy alloy particle-reinforced magnesium matrix composites prepared in Examples 1-5 of this invention have both high strength and high plasticity. The increase in the content of high-entropy alloy particles in the composites improves the yield strength and tensile strength. Furthermore, the composites prepared from magnesium matrices with high Al content have higher strength, while the composites prepared from magnesium matrices with high Zn content have better plasticity.

[0106] Furthermore, in Comparative Example 1, no reinforcing particles were added, and the yield strength, tensile strength, and elongation of the alloy material were significantly lower than those of the composite material. Comparative Example 2 used a high-Zn, low-Al magnesium matrix and increased the mass fraction of reinforcing particles to 25%. However, due to insufficient slurry flowability, the screw jammed, preventing injection. Therefore, if the raw material or component ratios and semi-solid injection parameters are not within the range specified in the embodiments of this invention, the slurry flowability and a wide process window cannot be guaranteed.

[0107] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing magnesium-based composite materials based on semi-solid injection molding, characterized in that, Includes the following steps: A semi-solid injection molding method was used to heat and stir a mixture of magnesium alloy matrix particles and high-entropy alloy powder in sequence, then injection mold and cool to obtain the sample. The sample was annealed to prepare the magnesium-based composite material; Of which, in terms of mass percentage, The magnesium alloy matrix particles include the following components: Aluminum: 1%–9%, ​​Zinc: 1%–7%, balance being magnesium and unavoidable impurities; The high-entropy alloy powder is a particle containing Al, Co, Cr, Fe and Ni elements, with a particle size of 0.5 to 50 μm.

2. The method for preparing magnesium-based composite materials based on semi-solid injection molding according to claim 1, characterized in that, The magnesium alloy matrix particles contain, in addition to magnesium and unavoidable impurities, 9% aluminum and 1% zinc.

3. The method for preparing magnesium-based composite materials based on semi-solid injection molding according to claim 1, characterized in that, The magnesium alloy matrix particles, in addition to magnesium and unavoidable impurities, contain 3% aluminum and 7% zinc.

4. The method for preparing magnesium-based composite materials based on semi-solid injection molding according to claim 1, characterized in that, In the magnesium-based composite material, the magnesium alloy matrix comprises 82–95 wt.% and the high-entropy alloy powder comprises 5–18 wt.%.

5. The method for preparing magnesium-based composite materials based on semi-solid injection molding according to claim 4, characterized in that, In the magnesium-based composite material, the high-entropy alloy powder accounts for 5.7 to 15.7 wt.%, with the balance being the magnesium alloy matrix.

6. The method for preparing magnesium-based composite materials based on semi-solid injection molding according to claim 1, characterized in that, The high-entropy alloy powder contains 6%–43% Al atoms and 20%–35% Ni atoms.

7. The method for preparing magnesium-based composite materials based on semi-solid injection molding according to claim 1, characterized in that, The heating process is carried out in the barrel in a segmented heating manner, with each segment having a temperature range of 480 to 630°C and a total heating time of 2 to 35 minutes.

8. The method for preparing magnesium-based composite materials based on semi-solid injection molding according to claim 1, characterized in that, The injection speed during the injection molding process is 1–5 m / s; the screw speed is 80–250 rpm; and the mold temperature is 200–350 °C; and / or, The annealing temperature during the annealing process is 150–300°C, and the time is 30 min–4 h.

9. A magnesium-based composite material, characterized in that, It is prepared by the method described in any one of claims 1-8.

10. The application of the magnesium-based composite material as described in claim 9 in the preparation of lightweight structures and components.

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