A method for preparing a SiC fiber reinforced aluminum matrix composite material with high compressive strength

Abstract

The application relates to the technical field of aluminum alloy composite materials, in particular to a preparation method of SiC fiber reinforced aluminum matrix composite material with high compressive strength. f SiC / 2024Al precursor wire is used as core material, the SiC / 2024Al precursor wire is loaded into a 2024Al alloy sheath, high-performance SiC / 2024Al composite material is prepared through sheath packaging, hot isostatic pressing and multi-stage heat treatment, etc. f The SiC fiber reinforced aluminum matrix composite material is composed of SiC fiber, a carbon layer, a 2024Al alloy matrix and a 2024Al alloy sheath in sequence, the obtained composite material matrix has uniform grain size and morphology, and there is no large-size second phase segregation. The matrix and the sheath are subjected to plasticity regulation through multi-stage heat treatment after the composite material is processed into a shape through the matrix coating fiber and the hot isostatic technology, and finally the SiC / 2024Al composite material with a room-temperature compressive strength of more than 3500MPa is obtained. f SiC / 2024Al composite material

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy composite materials technology, and in particular to a method for preparing a high compressive strength SiC fiber reinforced aluminum matrix composite material, which is applicable to load-bearing structures, high-temperature components and dynamic load environments in aerospace, new energy vehicles, high-end equipment and other fields where there are stringent requirements for lightweight materials and high compressive strength. Background Technology

[0002] Aluminum-based composites, due to their high specific strength, low density, and excellent thermal stability, have become core materials for lightweight design in aerospace, new energy vehicles, and high-end equipment. Compressive strength, as a key mechanical indicator, directly determines the reliability and service life of the material in load-bearing structures, high-temperature components, and under dynamic loads. However, existing technologies still face significant bottlenecks in achieving high compressive strength, high plastic deformation capacity, and adaptability to extreme environments, necessitating breakthroughs through innovation in material design and manufacturing processes.

[0003] Currently, improving the compressive strength of aluminum matrix composites faces major challenges related to the size characteristics of the reinforcing phase, uneven distribution of the reinforcing phase, and poor strength-ductility matching between the reinforcing phase and the matrix. Using large-sized reinforcing phases is a crucial method for improving the compressive strength of aluminum matrix composites; the size and uniformity of the reinforcing phase both affect the material's compressive strength. Furthermore, uneven distribution of large-sized reinforcing phases can lead to stress concentration within the material, accelerating composite failure. Additionally, a mismatch between the strength and ductility of the reinforcing phase and the matrix also hinders the achievement of optimal compressive strength.

[0004] Patent CN115679228A discloses a silicon carbide fiber-reinforced aluminum matrix composite material, its preparation method, and its application. It involves overlapping silicon carbide fiber bundles with aluminum alloy plates and employing vacuum hot pressing and vacuum pressure casting. However, the fiber bundles used are short strands ≤1K, resulting in a finished product with a tensile strength of only 750MPa and a bending strength of 840MPa. Furthermore, it fails to address the problem of early failure caused by stress concentration. Patent CN115961170A discloses a high-strength, high-resistance to intergranular corrosion SiCw-reinforced aluminum matrix composite material with a strength of 600MPa and its preparation method. It uses SiC whiskers as the reinforcing phase, combined with Ti alloyed 2000 series aluminum alloy, and employs cold isostatic pressing, hot isostatic pressing, plastic deformation, and heat treatment processes. However, its reinforcing phase is whiskers, failing to leverage the advantages of continuous fibers. The finished product has a tensile strength of only 602MPa, which cannot meet the service requirements under extreme environments. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing SiC fiber-reinforced aluminum matrix composites with high compressive strength. The method involves initially preparing SiC by coating the matrix with fibers and combining this with hot isostatic pressing. f / 2024Al composite material, through subsequent heat treatment to regulate the matrix structure to coordinate the strength and plasticity matching between the fiber and the matrix, obtained SiC fiber reinforced aluminum matrix composite material with a compressive strength of more than 3500MPa at room temperature, and at the same time solved the problems of interface brittleness and large residual stress of SiC fiber reinforced aluminum matrix composite material.

[0006] The technical solution of this invention is:

[0007] A method for preparing a high compressive strength SiC fiber-reinforced aluminum matrix composite material includes the following steps:

[0008] (1) Preparation of SiC f / 2024Al precursor wire: Rolled 2024Al alloy sputtering material is selected, with the total content of Mn, Si, and Fe impurities in the sputtering material being <1wt%, and the α-Al grains in the sputtering material being equiaxed with a size <50μm. 2 Before sputtering, the SiC fiber substrate is heated to 200~400℃, and a vacuum of 2×10⁻⁶ is maintained. -4 ~9×10 -4 Pa; control the sputtering current to 1~4A and the sputtering voltage to 290~340V to achieve a total sputtered coating thickness of 20~29μm, ensuring that the α-Al grain size in the precursor wire is <20μm. 2 After sputtering, the material is cooled to room temperature at a rate of 2~5℃ / min.

[0009] (2) 2024Al alloy sheathing: 2024Al alloy is selected as the sheathing material. The pilot wire from step (1) is cut into equal length segments. The length of the pilot wire is 4~8mm shorter than the sheath and the length difference of each wire is <1mm. After the pilot wire is inserted into the sheath, a vacuum is drawn. The sheath cap is welded by vacuum electron beam. The welding material is high-purity 2024Al alloy with impurity content <0.5wt%, so that the volume fraction of SiC fiber is 50%±5%.

[0010] (3) Hot isostatic pressing: Heat to 400-500℃ at a heating rate of 5-10℃ / min, and hold at 80-130MPa for 3-5 hours; then cool to 200℃ in the furnace, and hold at 90-140MPa for 1-3 hours; then cool to 100℃ in the furnace, and hold at 110-120MPa for 0.5-2 hours; finally cool to room temperature in the furnace.

[0011] (4) Multi-stage heat treatment: Heat to 200-300℃ at a heating rate of 6-10℃ / min, hold for 0.5-2h; then heat to 500-600℃ at a heating rate of 8-15℃ / min, hold for 1-3h, and water cool to room temperature.

[0012] (5) Machining: Machining the sample after step (4) until there are no obvious scratches on the surface.

[0013] The method for preparing the high compressive strength SiC fiber-reinforced aluminum matrix composite material, in step (1), the SiC fiber diameter is 100μm±5μm, the tensile strength is 3700~3900MPa, and the elastic modulus is 350~450GPa. The prepared SiC... f The total diameter of the 2024Al precursor filament is 150~170μm.

[0014] In the preparation method of the high compressive strength SiC fiber reinforced aluminum matrix composite material, in step (1), the composition of the 2024Al alloy matrix obtained on the surface of SiC fiber after sputtering is as follows by mass percentage: Cu 3~5%, Mg 1~2%, Mn 0~0.7%, Si 0~0.5%, Fe 0~0.3%, and Al balance.

[0015] In the preparation method of the high compressive strength SiC fiber reinforced aluminum matrix composite material, in step (1), a carbon layer with a thickness of 1~3μm is provided on the surface of the SiC fiber. The carbon layer is located between the SiC fiber and the 2024Al alloy matrix. The side closer to the SiC fiber is a pyrolytic carbon layer containing nanoscale silicon carbide particles, and the side closer to the 2024Al alloy matrix is ​​a pyrolytic carbon layer. The mass ratio of silicon carbide particles in the carbon layer is 5~15%.

[0016] In the preparation method of the high compressive strength SiC fiber reinforced aluminum matrix composite material, in step (2), the diameter of the sheath is 3~4mm, the thickness is 0.3~0.65mm, the pore size is 2.4~2.9mm, the size of the sheath increases accordingly as the size of the aluminum matrix composite material increases, and the volume fraction of SiC fiber is 50%.

[0017] The preparation method of the high compressive strength SiC fiber reinforced aluminum matrix composite material, the heat treatment regime in step (4) is as follows: heat up to 300℃ at a heating rate of 10℃ / min, hold for 1h, heat up to 550~600℃ at a heating rate of 8℃ / min, hold for 2h, and water cool to room temperature.

[0018] In the preparation method of the high compressive strength SiC fiber reinforced aluminum matrix composite material, step (5) involves mechanical processing after heat treatment.

[0019] The method for preparing the high compressive strength SiC fiber-reinforced aluminum matrix composite material describes a composite material in which the 2024Al alloy matrix and the 2024Al alloy cladding are uniformly structured, both consisting of alternating fine equiaxed α-Al, Al2Cu, and Al2CuMg phases. fThe 2024Al precursor fibers are evenly distributed in a hexagonal pattern, with no SiC fiber breakage.

[0020] The method for preparing the high compressive strength SiC fiber reinforced aluminum matrix composite material is described above. The SiC fiber reinforced aluminum matrix composite material is composed of SiC fibers, a carbon layer, a 2024Al alloy matrix, and a 2024Al alloy cladding. There is an amorphous carbon layer with a thickness of 15~60nm between the carbon layer and the 2024Al alloy matrix. There are no Al4C3 reaction products. After heat treatment, the room temperature compressive strength of the SiC fiber reinforced aluminum matrix composite material is above 3500MPa.

[0021] The design concept of this invention is:

[0022] Existing technologies suffer from defects in the morphology of the reinforcing phase or process design, resulting in low compressive strength of aluminum matrix composites. Furthermore, they generally exhibit interfacial brittleness, high residual stress, and a mismatch between strength and ductility. This invention addresses these issues by employing a solution involving material structure design, synergistic process control, and performance optimization to achieve a breakthrough in compressive strength and a balance in overall performance of continuous SiC fiber-reinforced aluminum matrix composites. The specific details are as follows:

[0023] Continuous SiC fibers with a tensile strength of approximately 3800 MPa and an elastic modulus of approximately 400 GPa were selected, and their volume fraction was precisely controlled to approximately 50%. The properties of continuous SiC fibers were utilized to provide high modulus support for the composite material. A gradient carbon layer (1-3 μm thick) was set between the SiC fibers and the matrix: high-purity pyrolytic carbon on the inner side and pyrolytic carbon containing nano-SiC particles on the outer side. The high-purity pyrolytic carbon on the inner side ensured a tight bond with the SiC fibers, while the nano-SiC particles on the outer side could form a mild interfacial interaction with the Al matrix, which not only blocked the excessive reaction between Al and C to avoid the formation of a brittle phase, but also improved the bonding force between the fibers and the matrix through the regulation of the interfacial microstructure.

[0024] During the preparation of the precursor wire, by controlling the purity of the sputtering target (Mn+Si+Fe < 1wt%), sputtering parameters (current 1~4A, voltage 290~340V), and slow cooling (2~5℃ / min), the α-Al grain size in the precursor wire is made <20μm. 2 This avoids stress concentration caused by large grains, enhances the strength of the matrix itself through fine grain strengthening, and reduces the initial residual stress between the precursor wire interface and the matrix by slow cooling.

[0025] In the segmented hot isostatic pressing process, a segmented temperature and pressure control strategy is adopted: heat and pressure holding at 400~500℃ → heat and pressure holding at 200℃ → heat and pressure holding at 100℃. The heat and pressure holding at 400~500℃ promotes the full wetting of the fiber by the matrix and realizes the densification of the material. The heat and pressure holding at 200℃ and 100℃ gradually releases the residual stress generated during the hot pressing process, while ensuring the homogenization of the 2024Al matrix and the cladding structure, and avoiding early material failure caused by stress concentration.

[0026] In the multi-stage heat treatment process, in order to address the problem of brittle fracture in high-strength materials, a multi-stage heat treatment of 200~300℃ and 500~600℃ is designed: the 200~300℃ holding temperature prepares for subsequent nucleation of precipitated phases, and the 500~600℃ holding temperature promotes the uniform distribution of fine precipitated phases such as Al2Cu and Al2CuMg in the matrix. The matrix strength is further improved through precipitation strengthening, and the plasticity of the material is improved by utilizing the dispersed distribution of precipitated phases.

[0027] The advantages and beneficial effects of this invention are:

[0028] 1. This invention uses SiC f High-performance SiC is prepared by using 2024Al precursor wire as the core material, encasing it in a 2024Al alloy sheath, and then performing vacuuming, electron beam welding, hot isostatic pressing, and multi-stage heat treatment. f The / 2024Al composite material yielded a matrix with uniform grain size and morphology, and no large-sized second phase segregation.

[0029] 2. This invention controls sputtering parameters (α-Al grains < 20 μm). 2 The precursor wire is slowly cooled (2~5℃ / min) and the temperature is controlled in stages by hot isostatic pressing to achieve uniform and refined matrix grains. The resulting composite material has a good degree of densification and uniform distribution of residual stress in the matrix.

[0030] 3. The present invention utilizes the synergistic effect of high modulus support of continuous SiC fibers (volume fraction of about 50%), interface reinforcement of gradient carbon layers, and precipitation reinforcement of multi-stage heat treatment to obtain a composite material with outstanding room temperature compressive strength of over 3500 MPa, which can meet the extreme load requirements of load-bearing structures in the aerospace field.

[0031] 4. The gradient carbon layer designed in this invention (the inner side contains a pyrolytic carbon layer with nanoscale silicon carbide particles and the outer side is a high-purity pyrolytic carbon layer), combined with hot isostatic pressing segmented temperature control and multi-stage heat treatment, makes only a 10~50nm amorphous carbon layer form at the interface, which greatly improves the interfacial bonding force between the fiber and the matrix and avoids early material damage caused by interfacial failure. Attached Figure Description

[0032] Figure 1The diagram shows the dimensions of a rod-shaped compression specimen. (a) is a cross-sectional view of the specimen, (b) is a side view of the specimen, and (c) is a view of SiC. f / Cross-section diagram of 2024Al precursor wire. Labels in the diagram: 1-2024Al alloy sheath, 2-SiC f / 2024Al precursor fiber (21-SiC fiber, 22-2024Al alloy matrix, 23-carbon layer).

[0033] Figure 2 The microstructure of the 2024Al alloy cladding is shown.

[0034] Figure 3 This is the room temperature compressive stress-displacement curve. Detailed Implementation

[0035] In the specific implementation process, SiC f The 2024Al precursor wire comprises SiC fibers, a 2024Al alloy matrix, and a carbon layer between them. The carbon layer thickness is 1-3 μm. The side closer to the SiC fibers is a pyrolytic carbon layer containing nanoscale silicon carbide particles, while the side closer to the 2024Al alloy matrix is ​​a high-purity (99.99 wt%) pyrolytic carbon layer. The mass ratio of silicon carbide particles in the carbon layer is 5-15%. The preparation process of the pyrolytic carbon layer is as follows: SiC is deposited simultaneously with the carbon layer by chemical vapor deposition. Deposition is stopped when the thickness reaches half, and then only the pyrolytic carbon layer is deposited to form a gradient carbon layer.

[0036] (1) Place the SiC fiber into the CVD reactor, and under argon protection, introduce methane, adjust the reaction temperature to 900~1100℃ and the pressure to 0.1~0.3MPa, and keep it at this temperature for 2~4h. Under these conditions, introduce a mixed gas of carbon source and silicon source, with methane as the carbon source (70~80% flow rate) and silicon tetrachloride as the silicon source (20~30% flow rate). The mixed gas undergoes a synergistic reaction at high temperature. On the one hand, the carbon source continues to decompose to produce carbon atoms, maintaining the continuous growth of the pyrolytic carbon layer. On the other hand, the silicon source reacts chemically with the carbon atoms decomposed from the carbon source. Since the reaction interface is the surface of the pure pyrolytic carbon layer, the generated SiC product is restricted by the pure pyrolytic carbon layer. In the pyrolytic carbon layer (0.5~1.5μm) near the SiC fiber, nano-SiC particles (5~50nm particle size) are generated in situ. The nano-SiC particles can hinder the overall graphitization of the carbon layer.

[0037] (2) Under argon protection, the temperature and pressure of the CVD reactor are kept constant. Methane is introduced under argon protection, and the reaction temperature is adjusted to 900~1100℃ and the pressure to 0.1~0.3MPa. The temperature is maintained for 2~4h. Under these conditions, the carbon source gas undergoes a thermal decomposition reaction on the surface of the SiC-containing carbon layer. Carbon atoms are uniformly deposited on the surface of the SiC-containing pyrolytic carbon layer, forming a high-purity pyrolytic carbon layer with a thickness of 0.5~1.5μm on the side close to the 2024Al matrix. Its function is to isolate the fiber from the subsequent reaction atmosphere, and to prevent the subsequently generated nano-SiC particles from directly adhering to the fiber surface, resulting in excessive interfacial bonding. At the same time, the flexibility of the pure carbon layer can buffer the difference in thermal expansion coefficients between the fiber and the matrix.

[0038] (3) After the reaction is complete, turn off the silicon source and carbon source, continue to introduce argon gas, and cool the reactor to room temperature at a cooling rate of 5~10℃ / min to avoid the agglomeration or oxidation of the nano-SiC particles generated at high temperature, and ensure the stability of the gradient carbon layer structure. This gradient carbon layer design avoids direct contact between SiC fibers and 2024Al, and provides a carbon source for the subsequent formation of amorphous carbon layers.

[0039] In addition, this invention uses the average grain area (square micrometers (μm)) 2 The α-Al grain size was statistically analyzed. Since α-Al grains are polycrystalline structural units in the 2024Al alloy matrix, exhibiting irregular equiaxed or columnar crystal morphology, their influence on the material's mechanical properties depends more on the actual area occupied by the grains in a two-dimensional cross-section. For grains of the same diameter, the ability to impede dislocation movement differs significantly depending on whether the cross-sectional shape is elongated or equiaxed. Therefore, the α-Al grain size was calculated using μm. 2 The two-dimensional area parameter can more accurately reflect the actual shape and size distribution of the grains.

[0040] The present invention will now be further described in detail with reference to embodiments and accompanying drawings.

[0041] Example 1 (Room Temperature Compression Performance Test)

[0042] This embodiment sputtered SiC f The target material used for the 2024Al precursor wire is a rolled 2024Al alloy target material. The total content of Mn, Si, and Fe impurities in the target material is less than 1 wt%, and the α-Al grains in the target material are equiaxed crystals with a size of less than 50 μm. 2 Before sputtering, the substrate (SiC fiber) was heated to 200°C and evacuated to a pressure of 2 × 10⁻⁶. -4 Pa. To ensure that the α-Al grain size in the precursor wire after sputtering is less than 20 μm. 2 The sputtering current was 1A, the sputtering voltage was 300V, and the total thickness of the sputtered coating (2024Al alloy substrate) was 25μm. The sputtered SiC...f The 2024Al precursor wire was slowly cooled to room temperature at a cooling rate of 2℃ / min to reduce residual stress at the interface and in the matrix. The sputtered 2024Al alloy matrix contained the following alloying elements: Cu: 3.8, Mg: 1.6, Mn: 0.4, Si: 0.3, Fe: 0.2, Al: balance (wt%). The SiC fiber diameter was approximately 100 μm, with a tensile strength of approximately 3800 MPa and an elastic modulus of approximately 400 GPa. The prepared SiC... f The total diameter of the 2024Al precursor wire is 150μm. A 2μm thick gradient carbon layer is designed on the surface of the SiC fiber. The pyrolytic carbon on the side closer to the SiC fiber contains nanoscale silicon carbide particles, and the mass ratio of silicon carbide particles in the carbon layer is 6%. The side closer to the 2024Al alloy matrix is ​​high-purity (99.99wt%) pyrolytic carbon.

[0043] like Figure 2 As shown, the cladding material in this embodiment is 2024Al alloy, and the microstructure is mainly composed of fine equiaxed α-Al grains. The α-Al grains are equiaxed and have a size of less than 50 μm. 2 Taking a small-sized rod as an example, the cladding diameter is 3.2 mm, the thickness is 0.3 mm, and the aperture is 2.6 mm. SiC... f The 2024Al precursor wires are cut to a length 5mm shorter than the sheath length, with the length difference between each precursor wire less than 1mm, to avoid compression and bending during installation. They are then inserted into the 2024Al alloy sheath, where the SiC fiber volume fraction is approximately 50% of the total volume. A vacuum is then applied to reduce the internal pressure of the material to below 2 × 10⁻⁶. -2 MPa, and the riser is welded together with a vacuum electron beam. The cap material and the sheath material are both high-purity 2024Al alloy with impurity content of less than 0.5wt%.

[0044] The hot isostatic pressing (HIP) process is as follows: the temperature is increased to 420℃ at a heating rate of 6℃ / min, held at 90MPa for 4 hours, then cooled in the furnace to 200℃, held at 100MPa for 2 hours, then cooled in the furnace to 100℃, held at 110MPa for 1 hour, and finally cooled in the furnace to room temperature. In this embodiment, the 2024Al alloy matrix microstructure after HIP control consists of alternating distributions of fine equiaxed α-Al, Al2Cu, and Al2CuMg phases, with an interfacial amorphous carbon layer thickness of 20nm and no Al4C3 reaction products. f The 2024Al precursor fibers are evenly distributed in a hexagonal pattern, and the prepared sample shows no SiC fiber breakage.

[0045] like Figure 1As shown, the SiC fiber-reinforced aluminum matrix composite material is a multi-layered gradient composite structure. Continuous SiC fibers 21 serve as the reinforcing phase, and a carbon layer 23 achieves a gradient transition between the SiC fibers 21 and the 2024Al alloy matrix 22. Finally, it is encapsulated by a 2024Al alloy sheath 1. f The 2024Al precursor wire 2 is uniformly arranged in an isohyet (approximately 50% by volume) within the 2024Al alloy sheath 1, adjacent to SiC f The space between the two SiC precursor wires is filled with 2024Al alloy, free of porosity or fracture defects, ensuring uniform load distribution. f In the 2024Al precursor filament 2, the interface between SiC fiber 21 and 2024Al alloy matrix 22 is a carbon layer 23. Under the action of hot isostatic pressing, carbon atoms from the pyrolysis carbon surface containing nanoscale silicon carbide particles near the 2024Al alloy matrix 22 slowly diffuse to the surface of the 2024Al alloy matrix 22 and accumulate to form an amorphous carbon layer on the surface of the 2024Al alloy matrix 22.

[0046] The hot isostatic pressing (HIP) specimens were subjected to heat treatment according to the following regime: heating to 200℃ at a rate of 10℃ / min, holding for 1 hour, then heating to 500℃ at a rate of 15℃ / min, holding for 2 hours, and finally water-cooled to room temperature. The specimens were then machined into cylindrical compression specimens with a diameter of 3 mm and a length of 4.5 mm. The surfaces of the machined specimens were polished with 600#, 2000#, and 3000# sandpaper, respectively, resulting in smooth, defect-free surfaces. The compressive properties of the composite material were then tested using a universal testing machine. The specific results are shown in Table 1.

[0047] Table 1 shows the room temperature compression performance.

[0048] Material Compression conditions Strength (MPa) Remark <![CDATA[SiC f / 2024Al]]> room temperature 3518 Compressed measured (engineering)

[0049] Example 2 (Room Temperature Compression Performance Test)

[0050] This embodiment sputtered SiC f The target material used for the 2024Al precursor wire is a rolled 2024Al alloy target material. The total content of Mn, Si, and Fe impurities in the target material is less than 1 wt%, and the α-Al grains in the target material are equiaxed crystals with a size of less than 50 μm. 2 Before sputtering, the substrate (SiC fiber) was heated to 230°C and evacuated to a pressure of 4 × 10⁻⁶. -4 Pa. To ensure that the α-Al grain size in the precursor wire after sputtering is less than 20 μm. 2 The sputtering current was 2A, the sputtering voltage was 310V, and the total thickness of the sputtered coating (2024Al alloy substrate) was 26μm. The sputtered SiC... fThe 2024Al precursor wire was slowly cooled to room temperature at a cooling rate of 3℃ / min to reduce residual stress at the interface and in the matrix. The sputtered 2024Al alloy matrix contained the following alloying elements: Cu: 3.8, Mg: 1.6, Mn: 0.4, Si: 0.3, Fe: 0.2, Al: balance (wt%). The SiC fiber diameter was approximately 100 μm, with a tensile strength of approximately 3800 MPa and an elastic modulus of approximately 400 GPa. The prepared SiC... f The total diameter of the 2024Al precursor wire is 152μm. A 2μm thick gradient carbon layer is designed on the surface of the SiC fiber. The pyrolytic carbon on the side closer to the SiC fiber contains nanoscale silicon carbide particles, and the mass ratio of silicon carbide particles in the carbon layer is 8%. The side closer to the 2024Al alloy matrix contains high-purity (99.99wt%) pyrolytic carbon.

[0051] like Figure 2 As shown, the cladding material in this embodiment is 2024Al alloy, and the microstructure is mainly composed of fine equiaxed α-Al grains. The α-Al grains are equiaxed and have a size of less than 50 μm. 2 Taking a small-sized rod as an example, the cladding diameter is 3.6 mm, the thickness is 0.5 mm, and the aperture is 2.6 mm. SiC... f The 2024Al precursor wires are cut to a length 5mm shorter than the sheath length, with the length difference between each precursor wire less than 1mm, to avoid compression and bending during installation. They are then inserted into the 2024Al alloy sheath, where the SiC fiber volume fraction is approximately 50% of the total volume. A vacuum is then applied to reduce the internal pressure of the material to below 2 × 10⁻⁶. -2 MPa, and the riser is welded together with a vacuum electron beam. The cap material and the sheath material are both high-purity 2024Al alloy with impurity content of less than 0.5wt%.

[0052] The hot isostatic pressing (HIP) process is as follows: the temperature is increased to 430℃ at a heating rate of 5℃ / min, held at 100MPa for 4 hours, then cooled in the furnace to 200℃, held at 110MPa for 2 hours, then cooled in the furnace to 100℃, held at 110MPa for 1 hour, and finally cooled in the furnace to room temperature. In this embodiment, the 2024Al alloy matrix microstructure after HIP control consists of alternating distributions of fine equiaxed α-Al, Al2Cu, and Al2CuMg phases, with an interfacial amorphous carbon layer thickness of 30nm and no Al4C3 reaction products. f The 2024Al precursor fibers are evenly distributed in a hexagonal pattern, and the prepared sample shows no SiC fiber breakage.

[0053] The hot isostatic pressing (HIP) specimens were subjected to heat treatment according to the following regime: heating to 300℃ at a rate of 10℃ / min, holding for 1 hour, then heating to 550℃ at a rate of 8℃ / min, holding for 2 hours, and finally water-cooled to room temperature. The specimens were then machined into cylindrical compression specimens with a diameter of 3 mm and a length of 4.5 mm. The surfaces of the machined specimens were polished with 600#, 2000#, and 3000# sandpaper, respectively, resulting in smooth, defect-free surfaces. The compressive properties of the composite material were then tested using a universal testing machine. The specific results are shown in Table 2.

[0054] Table 2 shows the room temperature compression performance.

[0055] Material Compression conditions Strength (MPa) Remark <![CDATA[SiC f / 2024Al]]> room temperature 4386 Compressed measured (engineering)

[0056] Example 3 (Room Temperature Compression Performance Test)

[0057] This embodiment sputtered SiC f The target material used for the 2024Al precursor wire is a rolled 2024Al alloy target material. The total content of Mn, Si, and Fe impurities in the target material is less than 1 wt%, and the α-Al grains in the target material are equiaxed crystals with a size of less than 50 μm. 2 Before sputtering, the substrate (SiC fiber) was heated to 300°C and evacuated to a pressure of 6 × 10⁻⁶. -4 Pa. To ensure that the α-Al grain size in the precursor wire after sputtering is less than 20 μm. 2 The sputtering current was 3A, the sputtering voltage was 320V, and the total thickness of the sputtered coating (2024Al alloy substrate) was 27μm. The sputtered SiC... f The 2024Al precursor wire was slowly cooled to room temperature at a cooling rate of 4℃ / min to reduce residual stress at the interface and in the matrix. The sputtered 2024Al alloy matrix contained the following alloying elements: Cu: 3.8, Mg: 1.6, Mn: 0.4, Si: 0.3, Fe: 0.2, and Al: balance (wt%). The SiC fiber diameter was approximately 100 μm, with a tensile strength of approximately 3800 MPa and an elastic modulus of approximately 400 GPa. The prepared SiC... f The total diameter of the 2024Al precursor wire is 154μm. A 3μm thick gradient carbon layer is designed on the surface of the SiC fiber. The side closer to the SiC fiber is pyrolytic carbon containing nanoscale silicon carbide particles, and the mass ratio of silicon carbide particles in the carbon layer is 10%. The side closer to the 2024Al alloy matrix is ​​high-purity (99.99wt%) pyrolytic carbon.

[0058] like Figure 2 As shown, the cladding material in this embodiment is 2024Al alloy, and the microstructure is mainly composed of fine equiaxed α-Al grains. The α-Al grains are equiaxed and have a size of less than 50 μm. 2Taking a small-sized rod as an example, the cladding diameter is 3.5mm, the thickness is 0.4mm, and the aperture is 2.7mm. SiC... f The 2024Al precursor wires are cut to a length 4mm shorter than the sheath length, with the length difference between each precursor wire less than 1mm, to avoid compression and bending during installation. They are then inserted into the 2024Al alloy sheath, where the SiC fiber volume fraction is approximately 50% of the total volume. A vacuum is then applied to reduce the internal pressure of the material to below 2 × 10⁻⁶. -2 MPa, and the riser is welded together with a vacuum electron beam. The cap material and the sheath material are both high-purity 2024Al alloy with impurity content of less than 0.5wt%.

[0059] The hot isostatic pressing (HIP) process is as follows: the temperature is increased to 400℃ at a heating rate of 8℃ / min, held at 110MPa for 4 hours, then cooled in the furnace to 200℃, held at 120MPa for 1 hour, then cooled in the furnace to 100℃, held at 120MPa for 0.5 hours, and finally cooled in the furnace to room temperature. In this embodiment, the 2024Al alloy matrix microstructure after HIP control consists of alternating distributions of fine equiaxed α-Al, Al2Cu, and Al2CuMg phases, with an interfacial amorphous carbon layer thickness of 40nm and no Al4C3 reaction products. f The 2024Al precursor fibers are evenly distributed in a hexagonal pattern, and the prepared sample shows no SiC fiber breakage.

[0060] The hot isostatic pressing (HIP) specimens were subjected to heat treatment according to the following regime: heating to 300℃ at a rate of 10℃ / min, holding for 1 hour, then heating to 570℃ at a rate of 8℃ / min, holding for 2 hours, and finally water-cooled to room temperature. The specimens were then machined into cylindrical compression specimens with a diameter of 3 mm and a length of 4.5 mm. The surfaces of the machined specimens were polished with 600#, 2000#, and 3000# sandpaper, respectively, resulting in smooth, defect-free surfaces. The compressive properties of the composite material were then tested using a universal testing machine. The specific results are shown in Table 3.

[0061] Table 3 shows the room temperature compression performance.

[0062] Material Compression conditions Strength (MPa) Remark <![CDATA[SiC f / 2024Al]]> room temperature 4118 Compressed measured (engineering)

[0063] Example 4 (Room Temperature Compression Performance Test)

[0064] This embodiment sputtered SiC f The target material used for the 2024Al precursor wire is a rolled 2024Al alloy target material. The total content of Mn, Si, and Fe impurities in the target material is less than 1 wt%, and the α-Al grains in the target material are equiaxed crystals with a size of less than 50 μm. 2Before sputtering, the substrate (SiC fiber) was heated to 360°C and evacuated to a pressure of 8 × 10⁻⁶. -4 Pa. To ensure that the α-Al grain size in the precursor wire after sputtering is less than 20 μm. 2 The sputtering current was 4A, the sputtering voltage was 330V, and the total thickness of the sputtered coating (2024Al alloy substrate) was 28μm. The sputtered SiC... f The 2024Al precursor wire was slowly cooled to room temperature at a cooling rate of 5℃ / min to reduce residual stress at the interface and in the matrix. The sputtered 2024Al alloy matrix contained the following alloying elements: Cu: 3.8, Mg: 1.6, Mn: 0.4, Si: 0.3, Fe: 0.2, and Al: balance (wt%). The SiC fiber diameter was approximately 100 μm, with a tensile strength of approximately 3800 MPa and an elastic modulus of approximately 400 GPa. f The total diameter of the 2024Al precursor wire is 156μm. A 3μm thick gradient carbon layer is designed on the surface of the SiC fiber. The pyrolytic carbon on the side closer to the SiC fiber contains nanoscale silicon carbide particles, and the mass ratio of silicon carbide particles in the carbon layer is 12%. The side closer to the 2024Al alloy matrix contains high-purity (99.99wt%) pyrolytic carbon.

[0065] like Figure 2 As shown, the cladding material in this embodiment is 2024Al alloy, and the microstructure is mainly composed of fine equiaxed α-Al grains. The α-Al grains are equiaxed and have a size of less than 50 μm. 2 Taking a small-sized rod as an example, the cladding diameter is 3.9 mm, the thickness is 0.6 mm, and the aperture is 2.7 mm. SiC... f The 2024Al precursor wires are cut to a length 4mm shorter than the sheath length, with the length difference between each precursor wire less than 1mm, to avoid compression and bending during installation. They are then inserted into the 2024Al alloy sheath, where the SiC fiber volume fraction is approximately 50% of the total volume. A vacuum is then applied to reduce the internal pressure of the material to below 2 × 10⁻⁶. -2 MPa, and the riser is welded together with a vacuum electron beam. The cap material and the sheath material are both high-purity 2024Al alloy with impurity content of less than 0.5wt%.

[0066] The hot isostatic pressing (HIP) process is as follows: the temperature is increased to 450℃ at a heating rate of 10℃ / min, held at 120MPa for 4 hours, then cooled in the furnace to 200℃, held at 130MPa for 1 hour, then cooled in the furnace to 100℃ at 120MPa for 0.5 hours, and finally cooled in the furnace to room temperature. In this embodiment, the 2024Al alloy matrix microstructure after HIP control consists of alternating distributions of fine equiaxed α-Al, Al2Cu, and Al2CuMg phases, with an interfacial amorphous carbon layer thickness of 50nm and no Al4C3 reaction products. f The 2024Al precursor fibers are evenly distributed in a hexagonal pattern, and the prepared sample shows no SiC fiber breakage.

[0067] The hot isostatic pressing (HIP) specimens were subjected to heat treatment according to the following regime: heating to 300℃ at a rate of 10℃ / min, holding for 1 hour, then heating to 570℃ at a rate of 8℃ / min, holding for 2 hours, and finally water-cooled to room temperature. The specimens were then machined into cylindrical compression specimens with a diameter of 3 mm and a length of 4.5 mm. The surfaces of the machined specimens were polished with 600#, 2000#, and 3000# sandpaper, respectively, resulting in smooth, defect-free surfaces. The compressive properties of the composite material were then tested using a universal testing machine. The specific results are shown in Table 4.

[0068] Table 4 shows the room temperature compression performance.

[0069] Material Compression conditions Strength (MPa) Remark <![CDATA[SiC f / 2024Al]]> room temperature 3818 Compressed measured (engineering)

[0070] Figure 3 The room temperature compressive stress-displacement curves for Examples 1-4 show that the peak values ​​of the stress-displacement curves for Examples 1-4 are all stably above 3500 MPa. Specifically, the peak value of the curve for Example 1 corresponds to 3518 MPa, for Example 2 to 4386 MPa, for Example 3 to 4118 MPa, and for Example 4 to 3818 MPa. The curve shapes of Examples 1-4 are generally consistent, indicating that the entire process of precursor fiber preparation, encapsulation, hot isostatic pressing, and heat treatment is stable, reliable, and highly controllable. On the one hand, the gradient carbon layer effectively buffers the stress transfer between the fiber and the matrix, avoiding significant delamination at the interface. On the other hand, the Al2Cu and Al2CuMg dispersed precipitates activated by multi-stage heat treatment not only improve strength but also suppress the rapid propagation of brittle cracks, meeting the requirements of high-end fields such as aerospace for extreme compressive load resistance.

[0071] The results show that this invention provides a method for preparing and subsequently heat-treating SiC fiber-reinforced aluminum matrix composites with a pressure resistance of 3500 MPa. The SiC fiber-reinforced aluminum matrix composite (SiC...) fThe 2024Al alloy composite material, from the inside out, consists of: SiC fibers, a carbon layer, a 2024Al alloy matrix, and a 2024Al alloy cladding. Each layer is continuously distributed along the length of the SiC fibers, forming an integral structure with continuous axial reinforcement and radial gradient bonding. After the composite material is processed and shaped using fiber coating and thermal isostatic techniques, the matrix and cladding undergo multi-stage heat treatment to control their strength and plasticity, ultimately yielding the desired SiC composite material. f The compressive strength of the 2024Al composite material at room temperature is above 3500 MPa.

[0072] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a high compressive strength SiC fiber-reinforced aluminum matrix composite material, characterized in that, Includes the following steps: (1) Preparation of SiC f / 2024Al precursor wire: Rolled 2024Al alloy sputtering material is selected, with the total content of Mn, Si, and Fe impurities in the sputtering material being <1wt%, and the α-Al grains in the sputtering material being equiaxed with a size <50μm. 2 Before sputtering, the SiC fiber substrate is heated to 200~400℃, and a vacuum of 2×10⁻⁶ is maintained. -4 ~9×10 -4 Pa; control the sputtering current to 1~4A and the sputtering voltage to 290~340V to achieve a total sputtered coating thickness of 20~29μm, ensuring that the α-Al grain size in the precursor wire is <20μm. 2 After sputtering, the material is cooled to room temperature at a rate of 2~5℃ / min. In step (1), a carbon layer with a thickness of 1~3μm is provided on the surface of SiC fiber. The carbon layer is located between SiC fiber and 2024Al alloy matrix. The side closer to SiC fiber is pyrolytic carbon containing nanoscale silicon carbide particles, and the side closer to 2024Al alloy matrix is ​​pyrolytic carbon. The mass ratio of silicon carbide particles in the carbon layer is 5~15%. (2) 2024Al alloy sheathing: 2024Al alloy is selected as the sheathing material. The pilot wire from step (1) is cut into equal length segments. The length of the pilot wire is 4~8mm shorter than the sheath and the length difference of each wire is <1mm. After the pilot wire is inserted into the sheath, a vacuum is drawn. The sheath cap is welded by vacuum electron beam. The welding material is high-purity 2024Al alloy with impurity content <0.5wt%, so that the volume fraction of SiC fiber is 50%±5%. (3) Hot isostatic pressing: Heat to 400-500℃ at a heating rate of 5-10℃ / min, and hold at 80-130MPa for 3-5 hours; then cool to 200℃ in the furnace, and hold at 90-140MPa for 1-3 hours; then cool to 100℃ in the furnace, and hold at 110-120MPa for 0.5-2 hours; finally cool to room temperature in the furnace. (4) Multi-stage heat treatment: Heat to 200-300℃ at a heating rate of 6-10℃ / min, hold for 0.5-2h; then heat to 500-600℃ at a heating rate of 8-15℃ / min, hold for 1-3h, and water cool to room temperature. (5) Machining: Machining the sample after step (4) until there are no obvious scratches on the surface.

2. The method for preparing the high compressive strength SiC fiber-reinforced aluminum matrix composite material according to claim 1, characterized in that, In step (1), the SiC fiber diameter is 100μm±5μm, the tensile strength is 3700~3900MPa, and the elastic modulus is 350~450GPa. The prepared SiC... f The total diameter of the 2024Al precursor filament is 150~170μm.

3. The method for preparing the high compressive strength SiC fiber-reinforced aluminum matrix composite material according to claim 1, characterized in that, In step (1), the composition of the 2024Al alloy matrix obtained on the surface of SiC fiber after sputtering is as follows by mass percentage: Cu 3~5%, Mg 1~2%, Mn 0~0.7%, Si 0~0.5%, Fe 0~0.3%, and Al balance.

4. The method for preparing the high compressive strength SiC fiber-reinforced aluminum matrix composite material according to claim 1, characterized in that, In step (2), the diameter of the sheath is 3~4mm, the thickness is 0.3~0.65mm, the aperture is 2.4~2.9mm, the size of the sheath increases accordingly as the size of the aluminum-based composite material increases, and the volume fraction of SiC fiber is 50%.

5. The method for preparing the high compressive strength SiC fiber-reinforced aluminum matrix composite material according to claim 1, characterized in that, The heat treatment process in step (4) is as follows: heat up to 300℃ at a heating rate of 10℃ / min, hold for 1 hour, heat up to 550~600℃ at a heating rate of 8℃ / min, hold for 2 hours, and then cool to room temperature with water.

6. The method for preparing the high compressive strength SiC fiber-reinforced aluminum matrix composite material according to claim 1, characterized in that, In step (5), the product is machined and shaped after heat treatment.

7. The method for preparing the high compressive strength SiC fiber-reinforced aluminum matrix composite material according to claim 1, characterized in that, In SiC fiber-reinforced aluminum matrix composites, both the 2024Al alloy matrix and the 2024Al alloy cladding microstructure are uniform, consisting of alternating distributions of fine equiaxed α-Al, Al2Cu, and Al2CuMg phases. f The 2024Al precursor fibers are evenly distributed in a hexagonal pattern, with no SiC fiber breakage.

8. The method for preparing the high compressive strength SiC fiber-reinforced aluminum matrix composite material according to claim 1, characterized in that, The SiC fiber-reinforced aluminum matrix composite material is composed of SiC fibers, a carbon layer, a 2024Al alloy matrix, and a 2024Al alloy cladding. There is an amorphous carbon layer with a thickness of 15~60nm between the carbon layer and the 2024Al alloy matrix. There are no Al4C3 reaction products. After heat treatment, the room temperature compressive strength of the SiC fiber-reinforced aluminum matrix composite material is above 3500MPa.

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