High-rigidity high-strength aluminum matrix composite material and preparation method thereof

Abstract

The application provides a high-rigidity high-strength aluminum matrix composite material and a preparation method thereof. The aluminum matrix composite material comprises an aluminum matrix and a reinforcing phase, the reinforcing phase comprises SiC@Al3BC particles with a core-shell structure and in-situ generated nano reinforcing particles; the mass percentage of the added SiC in the composite material is 10-40%, the SiC@Al3BC particles with the core-shell structure are uniformly distributed between aluminum matrix grains; the in-situ generated nano reinforcing particles are gamma-Al2O3 and / or AlN; the in-situ generated nano reinforcing particles are distributed along the grain boundaries of the aluminum matrix grains, and the mass percentage of the in-situ generated nano reinforcing particles is 2.9-16%. The application also provides a preparation method of the above composite material. The composite material has high rigidity and high strength, the elastic modulus reaches 100-140 GPa, and the ultimate tensile strength at room temperature reaches 350-500 MPa.

Description

Technical Field

[0001] This invention belongs to the field of metal matrix composites, specifically relating to a high-stiffness, high-strength aluminum matrix composite and its preparation method. Background Technology

[0002] Aluminum alloys possess a series of superior properties such as low density and high specific strength, making them an important basic material for high-end manufacturing fields such as transportation and national defense. However, traditional aluminum alloys have relatively low rigidity (also known as elastic modulus), only around 70 GPa, and even aluminum-lithium alloys, known for their high rigidity, generally do not exceed 90 GPa. Developing high-rigidity, low-density, and high-strength aluminum-based composite materials has significant application prospects and practical importance.

[0003] Because ceramic particles (such as SiC, γ-Al₂O₃, TiC, TiB₂, AlN, etc.) have high elastic moduli, introducing reinforcing particles into the aluminum matrix to develop aluminum matrix composites is an effective strategy to improve the rigidity of aluminum alloys and has become a research hotspot in recent years. Among them, SiC particles are commonly used as external reinforcements for aluminum matrix composites due to their low cost, excellent stiffness (elastic modulus reaches 324 GPa), and simple preparation process. Numerous studies have reported the preparation process, microstructure, and mechanical properties of SiC particle-reinforced aluminum matrix composites. However, most studies show that it is difficult for the Al matrix and SiC to wet below 900℃. Although increasing the reaction temperature can improve the wettability of the Al-SiC interface, the literature (T. Etter, et al., Materials Science and Engineering: A, 2007, 448: 1-6) indicates that the reaction product Al₄C₃ formed at the interface is a brittle phase, which significantly reduces the bonding strength between the Al matrix and SiC. Therefore, although composite materials prepared by this method can achieve a certain stiffness, their strength is low, which greatly limits their application range.

[0004] Unlike additive methods, aluminum-based composites prepared through in-situ endogenous reactions exhibit excellent bonding between the reinforcement and the interface, effectively transferring loads and improving material strength. Furthermore, the endogenous particles can also enhance the material's stiffness to some extent. Among numerous in-situ endogenous systems, Al3BC and γ-Al2O3, with particle densities similar to the aluminum matrix, are commonly used as endogenous particle reinforcement phases. However, due to the low solubility of boron, carbon, and oxygen in aluminum melt, the in-situ synthesis of Al3BC and γ-Al2O3 particles is difficult, complex, and often involves multiple chemical reactions, making reaction control challenging. Moreover, since the reinforcing particles originate from the chemical reaction between the aluminum melt and the precursor, the precursor content cannot be too high, otherwise it will lead to numerous material defects and difficulty in forming. The low precursor content fundamentally limits the extent to which the material's stiffness can be improved. Therefore, significantly and simultaneously improving the stiffness and strength of materials and developing novel high-stiffness, high-strength aluminum-based composites faces enormous challenges. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-stiffness, high-strength aluminum-based composite material and its preparation method.

[0006] This invention is achieved through the following means:

[0007] A high-stiffness, high-strength aluminum-based composite material is disclosed, comprising an aluminum matrix and a reinforcing phase. The reinforcing phase includes core-shell structured SiC@Al3BC particles and in-situ generated nano-reinforcing particles. The core-shell structured SiC@Al3BC particles have an added SiC particle core and an in-situ generated Al3BC particle shell, exhibiting an Al3BC-coated SiC core-shell structure. The added SiC in the composite material comprises 10–40% by mass, and the core-shell structured SiC@Al3BC particles are uniformly distributed between the aluminum matrix grains. The in-situ generated nano-reinforcing particles are γ-Al2O3 and / or AlN. The in-situ generated nano-reinforcing particles are distributed along the grain boundaries of the aluminum matrix grains, and the mass percentage of the in-situ generated nano-reinforcing particles is 2.9–16%.

[0008] According to a preferred embodiment of the present invention, the size of the aluminum matrix grains is 0.2 to 1 μm.

[0009] According to a preferred embodiment of the present invention, the size of the externally added SiC particles is 1 to 20 μm; the size of the in-situ generated Al3BC particles is 0.1 to 1 μm.

[0010] According to a preferred embodiment of the present invention, the size of the in-situ generated nano-reinforcing particles is 5 to 100 nm.

[0011] The preparation method of the above-mentioned high-stiffness and high-strength aluminum-based composite material includes the following steps:

[0012] (1) Prepare the required raw materials according to the following mass percentages: aluminum powder 49.7-87.9%, boronite 2.0-10.0%, silicon carbide powder 10.0-40.0%, catalyst 0.1-0.3%;

[0013] (2) Mix the aluminum powder, boronite, silicon carbide powder and catalyst in step (1), and ball mill the resulting material under an argon atmosphere to obtain a mixture.

[0014] (3) Degas the mixture obtained in step (2) and press it into a preform in a cold isostatic press;

[0015] (4) The preform is placed in a heating furnace for heat preservation treatment, and then extruded using a hot extruder to obtain a high-rigidity and high-strength aluminum-based composite material.

[0016] According to a preferred embodiment of the present invention, the aluminum powder size in step (1) is ≤80μm, and more preferably 1~50μm.

[0017] According to a preferred embodiment of the present invention, the boron body in step (1) is B2O3 and / or BN, and the size of the boron body is ≤10μm, more preferably 1-5μm.

[0018] According to a preferred embodiment of the present invention, the size of the silicon carbide powder in step (1) is ≤20μm, and more preferably 1~10μm.

[0019] According to a preferred embodiment of the present invention, the catalyst in step (1) is graphene oxide.

[0020] According to a preferred embodiment of the present invention, the rotation speed of the ball mill in step (2) is ≥300 r / min, more preferably 300-400 r / min; the ball milling time is 2-6 h, and the ball-to-material ratio is 5-12:1.

[0021] According to a preferred embodiment of the present invention, in step (3), the pressure of the cold isostatic press is 200-300 MPa.

[0022] According to a preferred embodiment of the present invention, the temperature of the heat preservation treatment in step (4) is 570℃~800℃, and the heat preservation time is 0.5~4h.

[0023] According to a preferred embodiment of the present invention, the extrusion ratio of the extruder in step (4) is 5 to 25:1.

[0024] The technical features and beneficial effects of this invention are as follows:

[0025] 1. In the aluminum-based composite material of this invention, γ-Al₂O₃, AlN, and Al₃BC particles are generated in situ, with clean and uncontaminated surfaces, exhibiting high interfacial bonding strength with the aluminum matrix. γ-Al₂O₃ and / or AlN nanoparticles are distributed along the grain boundaries of the matrix, fully utilizing their configurational strengthening effect to enhance material strength. High-modulus SiC is dispersed between grains, effectively increasing material stiffness and achieving strong bonding with the aluminum matrix through the in-situ formed SiC@Al₃BC core-shell structure, while simultaneously preventing the formation of the brittle Al₄C₃ phase. Based on the synergistic composite strengthening of these phases with different distributions, sizes, and structures, the composite material can achieve an elastic modulus of 100–140 GPa and a room-temperature ultimate tensile strength of 350–500 MPa.

[0026] 2. A specific amount of catalyst is added to the aluminum-based composite material of this invention. The catalyst can lower the reaction temperature, regulate the reaction process, and prevent Al3BC particles from growing into undesirable morphologies such as needles. Furthermore, due to the low density of γ-Al2O3, AlN, Al3BC, and SiC particles, the composite material prepared by this method has a density ≤2.8 g / cm³. 3 It has a significant lightweight characteristic.

[0027] 3. The method of the present invention is simple. By changing the ratio of aluminum powder, boronite and silicon carbide powder, the mass percentage and distribution characteristics of the reinforcing particles can be controlled. By changing the heat preservation temperature and time, the size of γ-Al2O3 or / and AlN particles, as well as the size of each part of the SiC@Al3BC core-shell structure, can be controlled, thereby customizing the strength and stiffness of the composite material according to the application requirements. Attached Figure Description

[0028] Figure 1 The image shows a transmission electron microscope (TEM) image of the high-rigidity, high-strength aluminum-based composite material prepared in Example 1. In the image, 1 represents SiC particles, 2 represents Al3BC particles formed in situ on the outer layer of SiC particles, 3 represents the aluminum matrix, and 4 represents in situ endogenous γ-Al2O3 particles.

[0029] Figure 2 Electron probe X-ray microscopy (EPXM) images of SiC@Al3BC core-shell structured particles in the high-stiffness, high-strength aluminum matrix composite material prepared in Example 1. Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments, but is not limited thereto.

[0031] Furthermore, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods; and unless otherwise specified, the reagents, materials and equipment are all commercially available.

[0032] The purity of the aluminum powder, boronite, and silicon carbide powder used in the examples was 99.9%.

[0033] Example 1

[0034] A method for preparing a high-stiffness, high-strength aluminum-based composite material includes the following steps:

[0035] (1) Prepare the required raw materials according to the following mass percentages: 84.8% spherical aluminum powder (approximately 1 μm in size), 5.0% boronite (B2O3 powder) (approximately 1 μm in size), 10.0% silicon carbide powder (approximately 1 μm in size), and 0.2% catalyst (graphene oxide);

[0036] (2) Mix the spherical aluminum powder, boron body, silicon carbide powder and catalyst in step (1), and ball mill the resulting material at high speed (360 r / min) for 2.5 h in an argon atmosphere. The ball-to-material ratio is set at 7:1 to obtain the mixture.

[0037] (3) The mixture obtained in step (2) is degassed and pressed into a preform in a cold isostatic press at a pressure of 200 MPa;

[0038] (4) The preform obtained in step (3) is placed in a heating furnace and kept at 750°C for 1.5 hours. It is then extruded using a hot extruder with an extrusion ratio of 10:1 to obtain a high-rigidity and high-strength aluminum-based composite material.

[0039] This embodiment yields a high-modulus, high-strength aluminum matrix composite material reinforced with γ-Al2O3 and SiC@Al3BC core-shell particles. The γ-Al2O3 particles have a size of approximately 20 nm and a mass fraction of 7.3%, distributed along the grain boundaries of the aluminum matrix. Al3BC particles are formed in situ around the SiC particles, with a size of 200 nm. The core-shell structured SiC@Al3BC particles are dispersed between the aluminum matrix grains. The composite material has an elastic modulus of 103 GPa and a room temperature ultimate tensile strength of 435 MPa.

[0040] Example 2

[0041] A method for preparing a high-stiffness, high-strength aluminum-based composite material includes the following steps:

[0042] (1) Prepare the required raw materials according to the following mass percentages: 57.7% spherical aluminum powder (approximately 20 μm in size), 2.0% boronite (BN powder) (approximately 5 μm in size), 40.0% silicon carbide powder (approximately 10 μm in size), and 0.3% catalyst (graphene oxide);

[0043] (2) Mix the spherical aluminum powder, boron body, silicon carbide powder and catalyst in step (1), and then ball mill the resulting material at high speed (300 r / min) for 6 h in an argon atmosphere. The ball-to-material ratio is set at 5:1 to obtain the mixture.

[0044] (3) The mixture obtained in step (2) is degassed and pressed into a preform in a cold isostatic press at a pressure of 300 MPa;

[0045] (4) The preform obtained in step (3) is placed in a heating furnace and kept at 800℃ for 0.5h. It is then extruded using a hot extruder with an extrusion ratio of 5:1 to obtain a high-rigidity and high-strength aluminum-based composite material.

[0046] This embodiment yields a high-modulus, high-strength aluminum matrix composite material reinforced with AlN and SiC@Al3BC core-shell particles. The AlN particles have a size of 80 nm and a mass fraction of 3.3%, distributed along the grain boundaries of the aluminum matrix. Al3BC particles with a size of 800 nm are formed in situ around the SiC particles, and the resulting core-shell SiC@Al3BC particles are dispersed between the aluminum matrix grains. The composite material has an elastic modulus of 138 GPa and a room temperature ultimate tensile strength of 365 MPa.

[0047] Example 3

[0048] A method for preparing a high-stiffness, high-strength aluminum-based composite material includes the following steps:

[0049] (1) Prepare the required raw materials according to the following mass percentages: 64.9% spherical aluminum powder (approximately 50 μm in size), 10.0% boronite (equal mass mixture of B2O3 and BN powders) (approximately 2 μm in size), 25.0% silicon carbide powder (approximately 5 μm in size), and 0.1% catalyst (graphene oxide);

[0050] (2) Mix the spherical aluminum powder, boron body, silicon carbide powder and catalyst in step (1), and ball mill the resulting material at high speed (ball mill speed 400 r / min) for 2 h in an argon atmosphere. The ball-to-material ratio is set at 10:1 to obtain the mixture.

[0051] (3) The mixture obtained in step (2) is degassed and pressed into a preform in a cold isostatic press at a pressure of 250 MPa;

[0052] (4) The preform obtained in step (3) is placed in a heating furnace and kept at 600℃ for 3 hours. It is then extruded using a hot extruder with an extrusion ratio of 20:1 to obtain a high-rigidity and high-strength aluminum-based composite material.

[0053] This embodiment yields a high-modulus, high-strength aluminum matrix composite material reinforced with γ-Al2O3, AlN, and SiC@Al3BC core-shell particles. The γ-Al2O3 particles have a size of approximately 10 nm and a mass fraction of 7.3%, while the AlN particles have a size of 30 nm and a mass fraction of 8.2%. Both types of particles are distributed along the grain boundaries of the aluminum matrix. Al3BC particles with a size of 200 nm are formed in situ around the SiC particles. The core-shell structured SiC@Al3BC particles are dispersed between the aluminum matrix grains. The composite material has an elastic modulus of 126 GPa and a room temperature ultimate tensile strength of 480 MPa.

Claims

1. A high-stiffness, high-strength aluminum-based composite material, characterized in that, The aluminum-based composite material comprises an aluminum matrix and a reinforcing phase. The reinforcing phase includes core-shell structured SiC@Al3BC particles and in-situ generated nano-reinforcing particles. The core-shell structured SiC@Al3BC particles have an added SiC particle core and an in-situ generated Al3BC particle shell, exhibiting an Al3BC-coated SiC core-shell structure. The added SiC in the composite material has a mass percentage of 10-40%, and the core-shell structured SiC@Al3BC particles are uniformly distributed between the aluminum matrix grains. The in-situ generated nano-reinforcing particles are γ-Al2O3 and / or AlN. The in-situ generated nano-reinforcing particles are distributed along the grain boundaries of the aluminum matrix grains, and the mass percentage of the in-situ generated nano-reinforcing particles is 2.9-16%.

2. The high-stiffness, high-strength aluminum-based composite material according to claim 1, characterized in that, The size of the aluminum matrix grains is 0.2~1μm; the size of the in-situ generated Al3BC particles is 0.1~1μm.

3. The high-stiffness, high-strength aluminum-based composite material according to claim 1, characterized in that, The size of the in-situ generated nano-reinforcing particles is 5~100nm.

4. A method for preparing the high-stiffness, high-strength aluminum-based composite material according to any one of claims 1-3, comprising the following steps: (1) Prepare the required raw materials according to the following mass percentages: aluminum powder 49.7~87.9%, boronite 2.0~10.0%, silicon carbide powder 10.0~40.0%, catalyst 0.1~0.3%; (2) Mix the aluminum powder, boronite, silicon carbide powder and catalyst in step (1), and ball mill the resulting material under an argon atmosphere to obtain a mixture. (3) Degas the mixture obtained in step (2) and press it into a preform in a cold isostatic press; (4) The preform is placed in a heating furnace for heat preservation treatment, and then extruded using a hot extruder to obtain a high-rigidity and high-strength aluminum-based composite material.

5. The method for preparing the high-stiffness, high-strength aluminum-based composite material according to claim 4, characterized in that, The aluminum powder size in step (1) is ≤80μm.

6. The method for preparing the high-stiffness, high-strength aluminum-based composite material according to claim 4, characterized in that, The aluminum powder in step (1) has a size of 1~50μm.

7. The method for preparing the high-stiffness, high-strength aluminum-based composite material according to claim 4, characterized in that, The boron body mentioned in step (1) is B2O3 and / or BN, and the size of the boron body is ≤10μm.

8. The method for preparing the high-stiffness, high-strength aluminum-based composite material according to claim 4, characterized in that, The size of the boron body mentioned in step (1) is 1~5 μm.

9. The method for preparing the high-stiffness, high-strength aluminum-based composite material according to claim 4, characterized in that, The size of the silicon carbide powder in step (1) is ≤20μm; the catalyst is graphene oxide.

10. The method for preparing the high-stiffness, high-strength aluminum-based composite material according to claim 4, characterized in that, The size of the silicon carbide powder mentioned in step (1) is 1~10μm.

11. The method for preparing the high-stiffness, high-strength aluminum-based composite material according to claim 4, characterized in that, The ball milling speed in step (2) is ≥300 r / min; the ball milling time is 2~6 h, and the ball-to-material ratio is 5~12:

1.

12. The method for preparing the high-stiffness, high-strength aluminum-based composite material according to claim 4, characterized in that, The rotation speed of the ball mill in step (2) is 300~400 r / min.

13. The method for preparing the high-stiffness, high-strength aluminum-based composite material according to claim 4, characterized in that, In step (3), the pressure of the cold isostatic press is 200~300MPa.

14. The method for preparing the high-stiffness, high-strength aluminum-based composite material according to claim 4, characterized in that, The temperature of the heat preservation treatment in step (4) is 570℃~800℃, and the heat preservation time is 0.5~4h; the extrusion ratio of the extruder is 5~25:1.

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