Preparation method for improving mechanical property of fiber-reinforced metal-based composite material

Abstract

The invention discloses a preparation method for improving the mechanical property of a fiber reinforced metal matrix composite, and belongs to the technical field of metal alloy composites.The preparation method comprises the steps that high-strength continuous fibers of specific specifications are prepared, stacked into multiple layers and then placed in a clamp, and multi-level interfaces such as PyC, Si C and BN are sequentially deposited on the surfaces of the fibers through the chemical vapor deposition technology; and the fiber prefabricated body and the metal alloy are combined through a hot pressing method, and the metal-based composite material with excellent performance and uniform and compact tissue is obtained. According to the method, the mechanical property of the metal-based composite material is effectively improved, light-weight treatment of the metal alloy is achieved, and a new thought is provided for performance improvement of the metal-based composite material.

Description

Technical Field

[0001] The present invention relates to the technical field of metal alloy composite materials, and in particular to a preparation method for improving the mechanical properties of fiber-reinforced metal matrix composite materials. Background Art

[0002] Although traditional metal alloys (such as aluminum alloys, magnesium alloys, titanium alloys, etc.) have mature preparation processes and good casting, forging and machining properties, their inherent limitations in mass-to-strength and mass-to-modulus make it difficult to meet the modern industry's demand for extreme lightweighting. With the urgent demand for lightweight and high-strength materials in the automotive and aerospace fields, traditional metal materials have faced performance bottlenecks. In contrast, Metal Matrix Composites (MMCs) have achieved a synergistic improvement in high specific strength, high specific modulus, corrosion resistance and oxidation resistance by introducing a reinforcing phase. They have now been widely used in aircraft load-bearing components, new energy vehicle structural parts and precision electronic devices. However, the existing MMCs preparation technology still has key problems such as uneven distribution of the reinforcing phase and insufficient interface bonding strength, which restricts its performance stability and engineering application potential.

[0003] Reinforcements such as carbon fiber, alumina fiber, ceramic fiber (such as SiC, Si3N4), metal fiber (W, Mo), glass fiber and aramid fiber generally have high temperature resistance, low thermal expansion coefficient, high elastic modulus and fatigue resistance, making them gradually replace traditional metal materials in the field of lightweight automobiles. By combining the ductility of the metal matrix with the high stiffness of the fiber reinforcement phase, a composite material system with both toughness and strength can be constructed, which can then be expanded to high-tech fields such as nanoelectronics and biomedicine. However, the traditional hot-pressing infiltration process is prone to thermal damage to the fiber (interfacial reaction in the molten state leads to strength degradation), which seriously deteriorates the material properties.

[0004] Therefore, providing a preparation method that can improve the mechanical properties of fiber-reinforced metal matrix composites is a problem that needs to be solved at present. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method for improving the mechanical properties of fiber-reinforced metal matrix composites. By in-situ depositing a nanoscale transition layer (such as a SiC coating), harmful interfacial reactions between the fiber and the matrix are suppressed, while optimizing the interfacial bonding strength and reducing the structural damage rate of the fiber during the composite process, thereby solving the problem of low mechanical properties of current composite materials and providing a new approach for the development of high-performance MMCs.

[0006] To achieve the above object, the present invention provides a preparation method for improving the mechanical properties of fiber-reinforced metal matrix composite materials, comprising the following steps:

[0007] Step 1: Providing a fiber and metal alloy substrate: 1) preparing two-dimensional or three-dimensional continuous fibers, fixing them with a fixture or crucible, and controlling the fiber spacing; 2) preparing a metal alloy, wherein the metal alloy includes at least one of an aluminum alloy, a magnesium alloy, a titanium alloy, a copper alloy, and a nickel alloy;

[0008] Step 2: Debonding the plain mesh continuous fiber: In a CVD tube furnace, introduce an inert gas at a flow rate of 10-300 ml / min and keep the fiber sheet at 600-1200°C for 1-3 hours;

[0009] Step 3: Depositing an interface layer: The fiber sheet is placed in a CVD tube furnace, and different gases are introduced in batches at different flow rates to deposit one or more layers of interface on the surface of the fiber sheet to obtain a fiber preform; the tube furnace is heated to 500-1500°C at a rate of 5-100°C / min. During the heating process, argon is introduced as a protective gas; the deposited interface layer includes one or more interfaces such as PyC, SiC, and BN;

[0010] Step 4: Prepare metal-based composite materials by hot pressing: Place the fiber preform in a customized mold and fix it, place the metal alloy on top of the mold, and use inert gas as a protective gas in an oxygen-free environment to prevent the metal alloy from undergoing oxidation reaction or forming an oxide film during the infiltration process, which will affect the performance of the composite material; set the furnace temperature to above the melting point of the metal alloy, and then maintain the furnace temperature above the melting point of the metal alloy through an insulation process to allow the metal matrix to fully melt and allow the metal and fiber to be evenly mixed; apply pressure and use the pressure to infiltrate the metal alloy melt into the fiber preform; when the pressure is over, the preform solidifies and hardens to obtain the required metal-based composite material.

[0011] Preferably, in the above-mentioned preparation method for improving the mechanical properties of fiber-reinforced metal matrix composite materials, in step 1, the continuous fiber is one of carbon fiber, alumina fiber, ceramic fiber, metal fiber, glass fiber, aramid fiber, natural fiber, etc., and the fiber diameter ranges from 5 to 200 μm; the density ranges from 1.4 to 3.9 g / cm 3 between.

[0012] Preferably, in the above-mentioned preparation method for improving the mechanical properties of fiber-reinforced metal matrix composite materials, in step 1, the element composition and content of the aluminum alloy are as follows: Cu is 0.15%-0.4%; Mg is 0.8%-1.2%; Si is 0.4%-0.8%; Mn is 0.04%-0.15%; Cr is 0.04%-0.35%; Zn is 0.25%; Ti is 0.15%; and Al is the balance;

[0013] The element composition and content of the magnesium alloy are as follows: Al is 3.0%-9.0%; Zn is 0.5%-1.5%; Mn is 0.1%-0.5%; Mg is the balance;

[0014] The element composition and content of the titanium alloy are as follows: Al is 4.0%-6.0%; Sn is 2.0%-3.0%; O is <0.2%; Ti is the balance;

[0015] The element composition and content of the copper alloy are as follows: Zn is 5%-40%; Be is 0.5%-2.0%; Cu is the balance;

[0016] The element composition and content of the nickel alloy are as follows: Cr is 20.5%-23%, Fe is 17%-20%, Mo is 8%-10%, and Ni is 47%-52%.

[0017] Preferably, in the above-mentioned preparation method for improving the mechanical properties of fiber-reinforced metal matrix composite materials, in step 2, the glue content of the fiber is about 1.5-2.5%.

[0018] Preferably, in the above-mentioned preparation method for improving the mechanical properties of fiber-reinforced metal matrix composite materials, in step 3, the processes of depositing the interfaces of PyC, SiC, BN, etc. are as follows:

[0019] Deposition of PyC interface: After heating to the required temperature, the tubular furnace is kept warm for 1-20 hours. During the holding period, CH4 gas is introduced at a flow rate of 10-200 ml / min. The pressure in the furnace is controlled at 0-25 kPa. CH4 is cracked at high temperature, and a layer of PyC interface is deposited on the fiber sheet;

[0020] Deposition of SiC interface: After heating to the required temperature, the tube furnace is kept warm for 0-20 hours. During the insulation process, H2 is introduced into the tube furnace in two ways. When H2 is used as a dilution gas, it is directly introduced into the tube furnace. When H2 is used as a carrier gas, it is introduced into a vacuum stainless steel tank filled with MTS and then into the tube furnace. H2 brings CH3SiCl3 into the tube furnace by bubbling. The flow rate of the dilution gas H2 is 20-180 ml / min. The flow rate ratio of H2 used as a dilution gas and a carrier gas is controlled at 1:1-5. The gas passes through the tube furnace and deposits a layer of SiC interface on the surface of the fiber sheet at high temperature.

[0021] Deposition of BN interface: After heating to the required temperature, the tubular furnace is kept warm for 1-8 hours, and BCl3 and NH4 gases are introduced at the same time, maintaining the flow ratio of the two gases at 1:1-5. After the BCl3 and NH3 gases react and decompose in the furnace tube, a layer of BN interface is deposited on the surface of the fiber sheet.

[0022] Preferably, in the above-mentioned preparation method for improving the mechanical properties of fiber-reinforced metal matrix composite materials, in step three, the deposition of PyC and SiC interfaces is carried out at a temperature of 800-1500°C, and the air pressure in the furnace is controlled at 0-20 kPa; the deposition of BN interfaces is carried out at a temperature of 500-1300°C, and the air pressure in the furnace is maintained in a vacuum state.

[0023] Preferably, in the above-mentioned preparation method for improving the mechanical properties of fiber-reinforced metal matrix composite materials, in step 4, the pressure required for the hot pressing method is 10-180 MPa.

[0024] Therefore, the present invention adopts the above-mentioned preparation method for improving the mechanical properties of fiber-reinforced metal matrix composite materials, which has the following beneficial effects:

[0025] 1) The technical core of the present invention is to controllably construct multi-component interface phases such as pyrolytic carbon (PyC), silicon carbide (SiC), and boron nitride (BN) inside the fiber preform through a chemical vapor deposition (CVD) process. By precisely controlling the gradient, thickness distribution, and uniformity of the chemical components of the interface phase, the directional construction of a multi-level heterogeneous interface structure on the fiber surface is achieved. The CVD-modified interface layer has dual functions: first, it inhibits harmful interface reactions between the fiber and the metal matrix; second, it optimizes the load transfer path and induces a crack deflection toughening mechanism. This strategy significantly improves the fracture toughness and crack propagation resistance of the composite material while reducing the processing damage rate of the fiber reinforcement. This technology breaks through the limitations of traditional interface modification methods and provides an innovative solution for the development of high-performance fiber-reinforced metal-based composite materials.

[0026] 2) The present invention's preparation process utilizes hot pressing technology, which optimizes the kinetics of molten metal infiltration to effectively suppress the formation of internal pore defects in the composite material and significantly improve the material's density. Combined with high-pressure solidification technology, this significantly refines the metal matrix's grains and homogenizes its microstructure, resulting in an optimized balance of strength and toughness for the composite material.

[0027] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a local scanning electron microscope (SEM) morphology image of the fiber-reinforced metal matrix composite material of the present invention;

[0029] Figure 2 This is a scanning electron microscope (SEM) morphology image of the fiber-reinforced metal matrix composite material in Example 1 of the present invention;

[0030] Figure 3 This is an energy spectrum (EDS) diagram of the fiber-reinforced metal matrix composite material in Example 1 of the present invention;

[0031] Figure 4 This is a scanning electron microscope (SEM) fracture image of the fiber-reinforced metal matrix composite material in Example 1 of the present invention;

[0032] Figure 5 XRD spectra of the fiber-reinforced metal matrix composite materials in Examples 2 and 3 of the present invention;

[0033] Figure 6 Graphs showing three-point bending-force-displacement curves of the fiber-reinforced metal matrix composite materials in Examples 2, 3, and 4 of the present invention. DETAILED DESCRIPTION

[0034] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] The terms used in the embodiments of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The singular forms "a," "an," "the," and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, and unless the context clearly indicates otherwise, "a plurality" generally includes at least two.

[0036] It should also be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or device. In the absence of further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the product or device comprising the element.

[0037] The present invention provides a preparation method for improving the mechanical properties of fiber-reinforced metal matrix composite materials, such as Figure 1 As shown, the method includes:

[0038] Step 1: Provide fiber and metal alloy substrate:

[0039] Specifically, continuous fibers, including carbon fibers, alumina fibers, ceramic fibers, metal fibers, glass fibers, aramid fibers, natural fibers, etc., are prepared, fixed with a fixture or a crucible, and the fiber spacing is controlled;

[0040] The carbon fiber, alumina fiber, ceramic fiber, metal fiber, glass fiber, aramid fiber, natural fiber, etc. are continuous fibers with a fiber diameter ranging from 5 to 200 μm and a density ranging from 1.4 to 3.9 g / cm 3 between.

[0041] Specifically, metal alloys such as aluminum alloy, magnesium alloy, titanium alloy, copper alloy, and nickel alloy are prepared;

[0042] The elemental composition and content of the aluminum alloy are as follows: Cu: 0.15%-0.4%; Mg: 0.8%-1.2%; Si: 0.4%-0.8%; Mn: 0.04%-0.15%; Cr: 0.04%-0.35%; Zn: 0.25%; Ti: 0.15%; and Al: balance.

[0043] The element composition and content of the magnesium alloy are: Al: 3.0%-9.0%; Zn: 0.5%-1.5%; Mn: 0.1%-0.5%; Mg: balance.

[0044] The element composition and content of the titanium alloy are: Al: 4.0%-6.0%; Sn: 2.0%-3.0%; O: <0.2%; Ti: balance.

[0045] The element composition and content of the copper alloy are: Zn: 5%-40%; Be: 0.5%-2.0%; Cu: balance.

[0046] The element composition and content of the nickel alloy are: Cr: 20.5%-23%; Fe: 17%-20%; Mo: 8%-10%; Ni: 47%-52%.

[0047] Step 2: Debonding of plain mesh continuous fibers:

[0048] Specifically, in a CVD tube furnace, an inert gas with a flow rate of 10-300 ml / min is introduced, and the continuous fiber sheet is kept at a temperature of 600-1200° C. for 1-3 hours; the obtained fiber sheet has a glue content of about 1.5-2.5%, and the glue weight is removed when calculating the thickness.

[0049] Step 3: Deposition of PyC, SiC, BN and other interfaces:

[0050] Specifically, a fiber sheet is placed in a CVD tube furnace, and different gases are introduced in batches at varying flow rates to deposit one or more interfaces on the fiber sheet surface, yielding a fiber preform. The tube furnace is heated at a rate of 5-100°C / min to a temperature of 500-1500°C. During this heating process, argon is introduced as a protective gas.

[0051] Deposition of PyC interface: After heating to the required temperature, the tubular furnace is kept warm for 1-20 hours. During the insulation, CH4 gas is introduced at a flow rate of 10-200 ml / min. The gas pressure in the furnace is controlled at 0-25 kPa. CH4 is cracked at high temperature and a layer of PyC interface is deposited on the surface of the fiber sheet.

[0052] Deposition of SiC interface: After heating to the required temperature, the tubular furnace is kept warm for 0-20 hours. During the insulation process, H2 is introduced into the tubular furnace in two ways. When H2 is used as a dilution gas, it is directly introduced into the tubular furnace. When H2 is used as a carrier gas, it is introduced into a vacuum stainless steel tank filled with MTS and then into the tubular furnace (H2 brings CH3SiCl3 into the tubular furnace by bubbling). The flow rate of the dilution gas H2 is 20-180 ml / min, and the flow ratio of H2 used as a dilution gas and a carrier gas is controlled at 1:1-5. The gas passes through the tubular furnace and deposits a layer of SiC interface on the surface of the fiber sheet at high temperature.

[0053] Deposition of BN interface: After heating to the required temperature, the tubular furnace is kept warm for 1-8 hours, and BCl3 and NH4 gases are introduced at the same time, maintaining the flow ratio of the two gases at 1:1-5. After the BCl3 and NH3 gases react and decompose in the furnace tube, a layer of BN interface is deposited on the surface of the fiber sheet.

[0054] Specifically, the CVD-PyC / SiC interface is carried out at a temperature of 800-1500°C, and the pressure in the furnace is controlled at 0-20kPa; the CVD-BN interface is carried out at a temperature of 500-1300°C, and the pressure in the furnace is maintained in a vacuum state.

[0055] Step 4: Preparation of metal matrix composite materials by hot pressing:

[0056] Specifically, the fiber preform is first placed in a customized mold and fixed, and the metal alloy is placed above the mold. Inert gas is used as a protective gas in an oxygen-free environment to prevent the metal alloy from undergoing oxidation reaction or forming an oxide film during the infiltration process, which affects the performance of the composite material. The furnace temperature is set to above the melting point of the metal alloy, and then maintained for a certain period of time through an insulation process to allow the metal matrix to fully melt and ensure that the metal and fiber can be evenly mixed. Apply a suitable pressure and use pressure to infiltrate the metal alloy melt into the carbon fiber preform. When the pressure is over, the preform solidifies and hardens, and the desired metal matrix composite material is obtained. The pressure required for the hot pressing method is relatively large, between 10-180MPa.

[0057] The present invention proposes an innovative preparation process, which uses chemical vapor deposition (CVD) technology to gradiently deposit multilayer interface coatings (such as PyC, SiC, BN, etc.) on the surface of flat stacked continuous fiber sheets, and then places the modified fiber preform and metal alloy in an inert gas protection atmosphere, and achieves composite densification by hot pressing assisted melt infiltration. This process optimizes the fiber-matrix interface bonding strength through interface engineering and successfully prepares high-performance continuous fiber reinforced metal matrix composites. Experimental results show that the key mechanical performance indicators of the obtained composite materials, such as three-point bending strength, tensile strength and Vickers hardness, are significantly improved. This technology has the advantages of both process simplicity and high repeatability, can achieve uniform distribution of fibers in the matrix and controllable adjustment of material properties, and has outstanding potential for industrial application.

[0058] In order to illustrate the technical solution of the present invention in detail, the following is a description of the embodiment: using the T700 grade high-strength carbon fiber imported from the United States as the reinforcement, 6061 aluminum alloy as the matrix material, and the carbon fiber reinforced aluminum matrix composite material prepared according to the above process, its typical micromorphology is as follows Figure 1 Scanning electron microscopy (SEM) was used to characterize the fiber morphology and interface structure, while energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were used to analyze the elemental distribution and phase composition. The three-point bending strength was measured using a universal testing machine. The results showed that the optimized composite material exhibited good interfacial bonding, significantly improved fiber distribution uniformity, and a three-point bending strength increase of approximately 126.3% compared to the unmodified system.

[0059] Example 1

[0060] S1. Prepare 12 woven carbon fiber sheets measuring 4 × 6.5 cm. Divide them into two equal groups of 6 sheets each. Stack them flat and place them in a graphite fixture in two layers, with a spacing of approximately 2 mm. The mass of the upper carbon fiber group is 2.8992 g, and the mass of the lower carbon fiber group is 2.8654 g. After removing the glue from the fibers obtained in the debonding step, the actual masses are approximately 2.8412 g and 2.8081 g, respectively.

[0061] S2. Place the graphite fixture in a tube furnace. Turn on the vacuum pump to evacuate the furnace, then introduce inert gas as a protective gas. Set the furnace program to heat up to 1100°C at a rate of 10°C / min. During this process, the glue contained in the carbon fiber sheet will be removed.

[0062] S3. After the temperature rises to 1100℃, keep it warm for 1 hour. While closing the inert gas pipeline, open the CH4 gas cylinder and the access switch, adjust its flow rate to 100ml / min, and adjust the vacuum valve so that the gas pressure in the furnace tube remains at around 3kPa.

[0063] S4. After keeping warm for 1 hour, continue to keep warm for 4 hours. At the same time, close the CH4 gas cylinder and the access switch, and then open the two hydrogen channels for dilution and carrier gas. The dilution hydrogen flow rate is adjusted to 70ml / min. The carrier hydrogen passes through the MTS tank and takes out the MTS by bubbling. The carrier hydrogen flow rate is controlled at 150ml / min, and the air pressure in the furnace tube is still maintained at about 3kPa.

[0064] S5. After 4 hours of holding, the tube furnace program ends. The MTS inlet and outlet switches are closed, allowing only hydrogen to flow through the furnace tubes. After 10 minutes of cleaning the tubes, the hydrogen cylinder and its access switch are closed. Argon is introduced again while the tube furnace cools down. The sample is removed after the furnace cools to room temperature. The sample obtained at this point is free of glue. After weighing, the CVD-PyC interface thickness is calculated to be 0.03 μm, and the CVD-SiC interface thickness is 0.97 μm.

[0065] S6. Place 6061 aluminum alloy on top of the mold where the carbon fiber preform is placed. Then use argon as a protective gas in an oxygen-free environment. When the temperature rises to 800°C, apply a pressure of 80 MPa to squeeze the molten 6061 aluminum alloy into the carbon fiber preform, and finally obtain a CVD-coated carbon fiber reinforced aluminum-based composite material.

[0066] Example 2

[0067] The preparation method of this continuous carbon fiber reinforced aluminum-based composite material is different from that of Example 1 in that: the mass of the upper carbon fiber group is 2.5746 g, and the mass of the lower carbon fiber group is 2.7554 g; the holding time of the deposited PyC interface is 2 h, and the holding time of the deposited SiC interface is 4 h; the CVD-PyC interface thickness is 0.06 μm, and the CVD-SiC interface thickness is 0.97 μm.

[0068] Example 3

[0069] The preparation method of this continuous carbon fiber reinforced aluminum-based composite material is different from that of Example 1 in that: the mass of the upper carbon fiber group is 2.6338 g, and the mass of the lower carbon fiber group is 2.3443 g; the holding time of the deposited PyC interface is 3 h, and the holding time of the deposited SiC interface is 4 h; the CVD-PyC interface thickness is 0.09 μm, and the CVD-SiC interface thickness is 0.97 μm.

[0070] Example 4

[0071] The preparation method of this continuous carbon fiber reinforced aluminum-based composite material is different from that of Example 1 in that: the mass of the upper carbon fiber group is 2.9584 g, and the mass of the lower carbon fiber group is 3.0225 g; the holding time of the deposited PyC interface is 4 h, and the holding time of the deposited SiC interface is 4 h; the CVD-PyC interface thickness is 0.12 μm, and the CVD-SiC interface thickness is 0.97 μm.

[0072] Comparative Example 1

[0073] The preparation method of the continuous carbon fiber reinforced aluminum-based composite material is different from that of Example 1 in that: the mass of the upper carbon fiber group is 2.8665 g, and the mass of the lower carbon fiber group is 2.7786 g; the holding time of the deposited PyC interface is 0 h, and the holding time of the deposited SiC interface is 4 h; the CVD-PyC interface thickness is 0, and the CVD-SiC interface thickness is 0 μm, and the CVD-SiC interface thickness is 0.97 μm.

[0074] Comparative Example 2

[0075] The preparation method of this continuous carbon fiber reinforced aluminum-based composite material is different from that of Example 1 in that: the mass of the upper carbon fiber group is 3.0445 g, and the mass of the lower carbon fiber group is 2.8857 g; the holding time of the deposited PyC interface is 0 h, and the holding time of the deposited SiC interface is 0 h; no interface is deposited, and the thickness of the CVD-PyC / SiC interface is 0.

[0076] like Figure 1 As shown, a continuous and uniform CVD interface layer can be observed on the carbon fiber surface; combined with Figure 2 Scanning electron microscope morphology analysis shows that the fiber bundles and the aluminum matrix are densely bonded, and the interface protective layer effectively inhibits the interface reaction between high-temperature molten aluminum and carbon fibers. Figure 6 The flexural strength test results show that the presence of the interface layer significantly improves the three-point bending strength of the composite material (about 126.3% higher than that of the unmodified system). Figure 4 The fracture morphology shows that the energy dissipation mechanisms such as fiber pullout, interface debonding and interlayer peeling significantly increase the crack growth threshold, indicating that the composite material has excellent toughness strengthening characteristics. Figure 4 The EDS element distribution map and Figure 5 The XRD phase analysis results confirm that the interface layer is a gradient PyC / SiC composite interface layer prepared by chemical vapor deposition (CVD). Figure 6The load-displacement curve further shows that with the extension of PyC interface deposition time (thickness increases from 0.03μm to 0.12μm), the flexural strength of the composite material shows a gradient optimization trend, and the mechanical properties of the CVD-PyC / SiC interface modified sample are improved by more than 126.3% compared with the undeposited interface sample, verifying the key role of interface engineering design in material strengthening and toughening.

[0077] Therefore, the present invention adopts the above-mentioned preparation method for improving the mechanical properties of fiber-reinforced metal matrix composites. Through the chemical vapor deposition (CVD) process, a multi-component interface phase such as pyrolytic carbon (PyC), silicon carbide (SiC), and boron nitride (BN) is controllably constructed inside the fiber preform. By precisely controlling the chemical component gradient, thickness distribution, and uniformity of the interface phase, the directional construction of a multi-level heterogeneous interface structure on the fiber surface is achieved. The CVD-modified interface layer has dual functions: first, it inhibits harmful interface reactions between the fiber and the metal matrix; second, it optimizes the load transfer path and induces a crack deflection toughening mechanism. This strategy significantly improves the fracture toughness and crack propagation resistance of the composite material while reducing the processing damage rate of the fiber reinforcement. This technology breaks through the limitations of traditional interface modification methods and provides an innovative solution for the development of high-performance fiber-reinforced metal matrix composites. The preparation process adopts hot pressing molding technology, which effectively inhibits the formation of pore defects inside the composite material by optimizing the kinetic conditions of molten metal infiltration, significantly improving the material density. Combined with high-pressure solidification technology, the metal matrix grains are significantly refined and the microstructure is homogenized, so that the composite material obtains an optimized strength-toughness match.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A preparation method for improving the mechanical properties of fiber-reinforced metal matrix composite materials, characterized in that: The steps include: Step 1: Providing a fiber and metal alloy substrate: 1) preparing two-dimensional or three-dimensional continuous fibers, fixing them with a fixture or crucible, and controlling the fiber spacing; 2) preparing a metal alloy, wherein the metal alloy includes at least one of an aluminum alloy, a magnesium alloy, a titanium alloy, a copper alloy, and a nickel alloy; Step 2: Debonding the plain mesh continuous fiber: In a CVD tube furnace, introduce an inert gas at a flow rate of 10-300 ml / min and keep the fiber sheet at 600-1200°C for 1-3 hours; Step 3: Depositing the interface layer: The fiber sheet is placed in a CVD tube furnace, and different gases are introduced in batches at different flow rates to deposit one or more layers of interface on the surface of the fiber sheet to obtain a fiber preform; the tube furnace is heated at a rate of 5-100°C / min to 500-1500°C. During the heating process, argon is introduced as a protective gas; The deposited interface layer includes one or more interfaces such as PyC, SiC, and BN; Step 4: Prepare the metal matrix composite material by hot pressing: The fiber preform is placed in a customized mold and fixed, and the metal alloy is placed on top of the mold. Inert gas is used as a protective gas in an oxygen-free environment to prevent the metal alloy from undergoing oxidation reaction or forming an oxide film during the infiltration process, which would affect the performance of the composite material. The furnace temperature is set to be above the melting point of the metal alloy, and then the furnace temperature is maintained above the melting point of the metal alloy through a heat preservation process to fully melt the metal matrix and allow the metal and fiber to be evenly mixed. Pressure is applied to infiltrate the metal alloy melt into the fiber preform; when the pressure ends, the preform solidifies and hardens to obtain the desired metal matrix composite material.

2. A preparation method for improving the mechanical properties of fiber-reinforced metal matrix composite materials according to claim 1, characterized in that: In step 1, the continuous fiber is at least one of carbon fiber, alumina fiber, ceramic fiber, metal fiber, glass fiber, aramid fiber, natural fiber, etc., with a fiber diameter ranging from 5 to 200 μm and a density ranging from 1.4 to 3.9 g / cm 3 .

3. The method for preparing a fiber-reinforced metal matrix composite material for improving mechanical properties according to claim 1, characterized in that: In step 1, the element composition and content of the aluminum alloy are as follows: Cu is 0.15%-0.4%; Mg is 0.8%-1.2%; Si is 0.4%-0.8%; Mn is 0.04%-0.15%; Cr is 0.04%-0.35%; Zn is 0.25%; Ti is 0.15%; and Al is the balance; The element composition and content of the magnesium alloy are as follows: Al is 3.0%-9.0%; Zn is 0.5%-1.5%; Mn is 0.1%-0.5%; Mg is the balance; The element composition and content of the titanium alloy are as follows: Al is 4.0%-6.0%; Sn is 2.0%-3.0%; O is <0.2%; Ti is the balance; The element composition and content of the copper alloy are as follows: Zn is 5%-40%; Be is 0.5%-2.0%; Cu is the balance; The element composition and content of the nickel alloy are as follows: Cr is 20.5%-23%, Fe is 17%-20%, Mo is 8%-10%, and Ni is 47%-52%.

4. The method for preparing a fiber-reinforced metal matrix composite material for improving mechanical properties according to claim 1, characterized in that: In step 2, the fiber contains about 1.5-2.5% glue.

5. The method for preparing a fiber-reinforced metal matrix composite material for improving mechanical properties according to claim 1, characterized in that: In step 3, the processes of depositing PyC, SiC, and BN interfaces are as follows: Deposition of PyC interface: After heating to the required temperature, the tubular furnace is kept warm for 1-20 hours. During the holding period, CH4 gas is introduced at a flow rate of 10-200 ml / min. The pressure in the furnace is controlled at 0-25 kPa. CH4 is cracked at high temperature, and a layer of PyC interface is deposited on the fiber sheet; Deposition of SiC interface: After heating to the required temperature, the tube furnace is kept warm for 0-20 hours. During the insulation process, H2 is introduced into the tube furnace in two ways. When H2 is used as a dilution gas, it is directly introduced into the tube furnace. When H2 is used as a carrier gas, it is introduced into a vacuum stainless steel tank filled with MTS and then into the tube furnace. H2 brings CH3SiCl3 into the tube furnace by bubbling. The flow rate of the dilution gas H2 is 20-180 ml / min. The flow rate ratio of H2 used as a dilution gas and a carrier gas is controlled at 1:1-5. The gas passes through the tube furnace and deposits a layer of SiC interface on the surface of the fiber sheet at high temperature. Deposition of BN interface: After heating to the required temperature, the tubular furnace is kept warm for 1-8 hours, and BCl3 and NH4 gases are introduced at the same time, maintaining the flow ratio of the two gases at 1:1-5. After the BCl3 and NH3 gases react and decompose in the furnace tube, a layer of BN interface is deposited on the surface of the fiber sheet.

6. The method for preparing a fiber-reinforced metal matrix composite material for improving mechanical properties according to claim 1, characterized in that: In step three, the PyC and SiC interfaces are deposited at a temperature of 800-1500°C, and the pressure in the furnace is controlled at 0-20 kPa; the BN interface is deposited at a temperature of 500-1300°C, and the pressure in the furnace is maintained in a vacuum state.

7. The method for preparing a fiber-reinforced metal matrix composite material for improving mechanical properties according to claim 1, characterized in that: In step 4, the pressure required for the hot pressing method is 10-180 MPa.

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