Fiber-reinforced metal-based composite material and preparation method thereof

Abstract

The invention discloses a fiber-reinforced metal-based composite material and a preparation method thereof, and belongs to the technical field of composite materials. The fiber-reinforced metal-based composite material is of a plate-shaped structure, the length is a, the width is b, the thickness is at least 7 mm, the fiber-reinforced metal-based composite material comprises a plurality of laminated metal thin layers, reinforced fibers are laid between the adjacent metal thin layers, the length of the reinforced fibers is smaller than or equal to (a2 + b2) 1 / 2, concave hole structures are distributed on the surfaces of the reinforced fibers, and the thickness of the metal thin layers is 0.5-3 mm. The preparation method comprises the following steps: S1, forming a metal thin layer; s2, laying reinforced fibers; s3, forming a multi-layer structure; s4, forming a composite material green body; s5, a micro-deformation process; and S6, a heat treatment procedure. According to the method, the reinforced fibers can be uniformly distributed, knotting or agglomeration of the reinforced fibers is avoided, interface contact is optimized, interface bonding is enhanced, and therefore the performance and mechanical stability of the composite material are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and more specifically, relates to a fiber-reinforced metal-based composite material and a preparation method thereof. Background Art

[0002] Fiber-reinforced metal matrix composites have been widely used in aerospace, automobile and high-end manufacturing fields due to their excellent mechanical properties, lightweight characteristics and good thermal and electrical conductivity. For example, carbon fiber reinforced metal matrix composites (CFMMC) combine the high strength and high modulus of carbon fiber with the processability, thermal conductivity and electrical conductivity of the metal matrix, and thus have shown great application potential in the engineering field where the demand for high-performance structural materials is growing. However, the existing preparation methods still face many technical difficulties, especially in the interface bonding strength between carbon fiber and metal matrix, where there are significant bottlenecks. The specific problems are mainly concentrated in the following aspects:

[0003] Carbon fiber agglomeration and segregation problems: In existing methods, short carbon fibers are prone to agglomeration and segregation in metal melts, resulting in uneven distribution of carbon fibers in the material, thus affecting the mechanical properties of the composite material. Especially in high-temperature metal melts, the dispersibility of short carbon fibers is poor, making it difficult to achieve uniform distribution, which affects the final composite material performance.

[0004] Difficulty in regulating interface reaction: The interface reaction between carbon fiber and metal matrix is ​​difficult to control, especially in the process of liquid metal and carbon fiber contact, the interface reaction is often too intense or too mild. Too intense interface reaction may lead to interface embrittlement, while insufficient reaction is difficult to effectively enhance the interface bonding strength, resulting in poor interface bonding.

[0005] High production cost and long cycle: Existing methods generally require high temperature and long processing time, resulting in high production cost, long production cycle and low efficiency. Therefore, how to reduce production cost, shorten production cycle and improve product performance is still an urgent problem to be solved.

[0006] In the prior art, liquid phase method, solid phase method and additive manufacturing method have been widely used in the preparation of carbon fiber reinforced metal matrix composites. However, each of these methods still has defects, especially in the regulation of interface bonding strength and carbon fiber dispersion, and fails to achieve the desired effect. The specific methods and their shortcomings are as follows:

[0007] 1. Stir Casting

[0008] Stir casting is a low-cost preparation process that mainly mixes metal melt with carbon fiber through mechanical stirring. Its advantage is low cost, but its disadvantages are also obvious:

[0009] Violent interface reaction: Since the stirring process will cause the metal melt and carbon fiber to be in contact for too long, the interface reaction is often more violent, which can easily lead to interface embrittlement and it is difficult to effectively control the degree of reaction.

[0010] Agglomeration and segregation phenomenon: During the solidification process of the metal melt, carbon fibers are prone to agglomeration and segregation, resulting in uneven distribution of carbon fibers and affecting the overall performance of the composite material.

[0011] 2. Squeeze Casting

[0012] The squeeze casting method applies high pressure to immerse the metal melt into the carbon fiber preform, thereby improving the interface wettability. The advantage of this method is that it improves the bonding between the metal and the carbon fiber, but there are also certain problems:

[0013] Damage to the carbon fiber skeleton: During the high-pressure impregnation process, excessive pressure may damage the skeleton structure of the carbon fiber, resulting in a decrease in its mechanical properties.

[0014] Difficulty in controlling interface reactions: Although the interface reactions have been alleviated, they are still quite violent under certain pressures, and it is difficult to completely avoid the occurrence of adverse reactions.

[0015] 3. Powder Metallurgy

[0016] Powder metallurgy can achieve near-net shape and flexibly adjust the type and proportion of carbon fiber, especially suitable for the use of short fibers. However, this method also faces the following limitations:

[0017] Not applicable to long carbon fibers: Powder metallurgy is generally not applicable to the preparation of long carbon fibers, especially continuous long carbon fibers, which limits its scope of application.

[0018] Low interface bonding strength: Due to the low sintering temperature of this method, the effective reaction between the metal matrix and the carbon fiber is not fully promoted, resulting in low interface bonding strength.

[0019] 4. Diffusion bonding method

[0020] The diffusion bonding method achieves the bonding of carbon fiber and metal matrix through lower sintering temperature and greater pressure. This method has a lower sintering temperature than the powder metallurgy method, but it also has the following problems:

[0021] A relatively high pressure is required. In order to reduce the interfacial reaction, a relatively high pressure is usually applied, which increases the complexity of the equipment and process.

[0022] The long preparation cycle of the diffusion bonding method affects the production efficiency and is difficult to adapt to large-scale production needs.

[0023] In summary, although the existing preparation methods have made some progress, there are still many problems in terms of interface reaction control, carbon fiber dispersion and interface bonding strength improvement. Therefore, how to improve the interface bonding strength between carbon fiber and metal matrix through new methods and achieve better interface reaction control is still a core technical problem that needs to be solved in this field. Summary of the invention

[0024] 1. Problem to be solved

[0025] One of the purposes of the present invention is to provide a fiber-reinforced metal matrix composite material, aiming to obtain a composite material with excellent mechanical properties.

[0026] Another object of the present invention is to provide a method for preparing a fiber-reinforced metal matrix composite material, so as to achieve uniform distribution of reinforcing fibers and avoid knotting or agglomeration thereof, optimize interface contact and enhance interface bonding, thereby improving the performance and mechanical stability of the composite material.

[0027] 2. Technical solution

[0028] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0029] According to the purpose of the present invention, the first aspect of the present invention provides a fiber-reinforced metal matrix composite material, which is a square plate structure with a length of a, a width of b, and a thickness of at least 7 mm, which can ensure strength (for example, 4 layers of metal and 3 layers of carbon fiber), including a plurality of stacked metal thin layers, and reinforcing fibers are laid between adjacent metal thin layers, and the length of the reinforcing fibers is less than or equal to (a 2 +b 2 ) 1 / 2 The reinforcing fiber surface is distributed with a recessed hole structure, wherein the thickness of the metal thin layer is 0.5 to 3 mm.

[0030] In the case of adopting the above technical solution, one of the innovative points of the present invention is to use reinforcing fibers with a width or length similar to that of the metal matrix. In the existing metal-based composite materials, short fibers are generally used for reinforcing fibers. The reinforcing fibers are dispersed in the molten metal by stirring casting and extrusion casting, which is prone to fiber agglomeration and segregation problems, resulting in uneven fiber distribution, thereby affecting performance; the length of the reinforcing fibers selected by the present invention can be laid between adjacent metal thin layers to ensure the uniformity of the distribution of the reinforcing fibers. At the same time, the second innovative point is to control the metal thin layer to be 0.5 to 3 mm thick. The metal thin layer of this thickness is conducive to increasing the distribution density of the reinforcing fibers in the metal-based composite material, thereby increasing the reinforcing performance. Finally, it cannot be ignored that the innovation of this application is also to achieve the production of ultra-thin metal-based composite materials, while ensuring the thickness is lightweight, it can also ensure the bonding strength.

[0031] As a possible implementation scheme, the laying area of ​​the reinforcing fibers accounts for 30% to 70% of the area of ​​the metal thin layer. The laying methods include but are not limited to parallel laying and cross laying, wherein, in parallel laying, the reinforcing fibers are arranged in parallel on the surface of the metal thin layer, and the laying area of ​​the reinforcing fibers accounts for no more than 50% of the area of ​​the metal thin layer; in cross laying, the reinforcing fibers are cross-distributed on the surface of the metal thin layer, and the laying area of ​​the reinforcing fibers accounts for 50% to 70% of the area of ​​the metal thin layer.

[0032] As a possible implementation scheme, the surface of the reinforcing fiber is coated with a coating, the coating is a nickel layer or a copper layer, and there is an intermetallic compound M-Ni between the reinforcing fiber and the metal thin layer. x or M-Cu x , wherein M is the metal type of the metal thin layer, x>0, and the thickness of the coating is 0.003mm to 0.015mm. This thickness range can not only improve the wettability of the carbon fiber and the metal matrix, but also avoid the excessive generation of interface brittle compounds.

[0033] In the case of adopting the above technical solution, the surface of the reinforcing fiber is pretreated to form a coating, and in the subsequent process of introducing the metal thin layer, an intermetallic compound M-Ni is formed. x or M-Cu x , which can enhance the interface bonding strength between the fiber and the metal thin layer. Among them:

[0034] When a nickel layer is uniformly formed on the surface of the reinforcing fiber, the interface bonding performance is enhanced through the combined action of chemical bonds and van der Waals forces. The transitional properties of the nickel layer reduce the wetting angle θ of the metal melt and improve the wettability. In addition, the nickel layer and the metal thin layer can form an intermetallic compound M-Ni by diffusion or chemical reaction. x , further enhancing the bonding strength.

[0035] When a copper layer is uniformly formed on the surface of the reinforcing fiber, the copper layer can reduce the interface residual stress and enhance the comprehensive mechanical properties of the interface due to its excellent thermal conductivity and high ductility; a diffusion reaction M+Cu→M-Cu will occur at the interface between copper and the metal thin layer. x , further improving the interface strength; the copper layer also provides excellent wettability, and the reduction of the wetting angle significantly improves the uniform distribution of the melt forming the metal thin layer on the fiber surface.

[0036] As a possible implementation scheme, the reinforcing fiber is carbon fiber or metal fiber, preferably carbon fiber.

[0037] When the above technical solution is adopted, the high strength and high modulus of carbon fiber and the processability, thermal conductivity and electrical conductivity of the metal matrix are often used as the reinforcing phase, but the present invention is not limited to carbon fiber, and other fibers with reinforcing effects can be used.

[0038] As a possible implementation scheme, the metal type of the metal thin layer is Sn, Zn, Al and alloys thereof, such as Zamak3 (Zn alloy No. 3).

[0039] A second aspect of the present invention provides a method for preparing a fiber-reinforced metal matrix composite material, the steps comprising:

[0040] S1, metal thin layer forming process: using flow casting printing method to prepare a single metal thin layer with a thickness of 0.5 to 3 mm;

[0041] S2, a step of laying reinforcing fibers: laying reinforcing fibers on the metal thin layer formed in step S1 to form a metal thin layer-reinforcing fiber structure;

[0042] S3, forming a multilayer structure process: on the metal thin layer-reinforcement fiber structure formed in step S2, repeat steps S1 to S2 N times, N ≥ 0, to form an intermediate structure of metal thin layer and reinforcement fiber stacking;

[0043] S4, forming a composite material blank process: on the surface of the reinforcing fiber of the intermediate structure in step S3, a metal thin layer with a thickness of 0.5 to 3 mm is prepared by a flow casting printing method to form a composite material blank;

[0044] S5, micro deformation process: hot rolling process is adopted for the composite material blank of step S4, and the deformation amount is controlled to be 5% to 10% of the height of the composite material blank;

[0045] S6, heat treatment process: heat treatment is performed on the composite material blank after the micro-deformation in step S5 to obtain a fiber-reinforced metal matrix composite material;

[0046] The flow casting printing method is performed using a flow casting printing prototype machine, which includes a heating area, a laying area below the heating area, and a control area:

[0047] The heating zone contains molten metal for heating to a molten state, and a water outlet is provided at the bottom for releasing the molten metal to the laying zone to form a thin metal layer; the laying zone includes a laying platform; the control zone is electrically connected to the heating zone and the laying zone, and is used to control the operation of the heating zone and the laying zone, including but not limited to controlling the heating of the heating zone, closing / releasing the melt at the water outlet, and moving the laying zone.

[0048] When adopting the above technical scheme, the key to the preparation method of the present invention is how to form an ultra-thin metal layer of 0.5 to 3 mm. The flow casting printing method is a method created by the applicant. The flow casting printing prototype developed by the applicant (recorded in "Research Progress of Carbon Fiber Reinforced Metal Matrix Composite Materials" in Volume 45, Issue 4 of "Shanghai Metal") can achieve the formation of an ultra-thin metal layer.

[0049] As a possible implementation scheme, in the casting printing method of step S1 and step S4, the thickness d of the metal thin layer satisfies formula (1):

[0050]

[0051] In formula (1), d is the thickness of the metal layer, v 2 is the moving speed of the laying platform, h is the height of the water outlet from the laying platform, η is the viscosity of the molten metal; ρ is the density of the molten metal, α is the thermal diffusivity of the molten metal, and k is the correction coefficient of the molten metal, which varies for different metals.

[0052] When the above technical solution is adopted, the thickness of the metal thin layer can be accurately controlled by controlling the process parameters of the flow casting printing method, that is, by adjusting v 1 、v 2 and h, under given material properties k, η, ρ, α, the target thickness d is obtained. Formula (1) proposes an accurate thin layer thickness prediction formula by combining the multi-physical field coupling of flow and solidification processes, which can effectively reflect the influence of various physical parameters of the melt during flow and cooling. The prediction formula is based on a flow-solidification coupling physical model combining fluid mechanics and thermodynamics, and fully considers the influence of the flow and solidification process of the metal melt on the thin layer thickness. The main parameters of the formula (1) include: melt viscosity (η), substrate speed (v2), thermal diffusivity (α), substrate height (h) and metal density (ρ). Through dimensional analysis, formula (1) considers both the stretching effect during the flow process and the cooling effect during the solidification process, and flexibly responds to the physical properties of different metal materials; formula (1) further improves the prediction accuracy through the correction coefficient, making it have a wide range of application potential in the preparation process of different metal thin layers. Formula (1) can accurately reflect the relationship between these parameters and the thickness of the metal thin layer.

[0053] As a possible implementation scheme, in the casting printing method of step S1 and step S4, the casting temperature of the metal melt is 180-680° C., and the moving speed of the laying platform is 1-3 m / s.

[0054] As a possible implementation scheme, step S2 includes pretreatment of the reinforcing fibers. The purpose of the pretreatment is to optimize the surface properties of the carbon fibers and significantly enhance the interfacial bonding performance between the carbon fibers and the metal melt. The pretreatment is performed by the following method:

[0055] Treatment for forming a concave hole structure: using sandblasting particles to impact the surface of the reinforcing fiber to form a concave hole structure, wherein the hardness grade of the sandblasting particles is 5 to 8 (Mohs hardness), and the particle size range of the sandblasting particles is 80 mesh to 120 mesh;

[0056] or,

[0057] S21. Treatment for forming a coating: forming a nickel layer or a copper layer on the surface of the reinforcing fiber; by forming a transition layer between metals, the chemical bond strength and wettability of the interface are improved;

[0058] S22, a process for forming a sunken hole structure: using sandblasting particles to impact the surface of the reinforcing fiber covered with a nickel layer or a copper layer in step S21 to form a sunken hole structure, wherein the hardness grade of the sandblasting particles is 5 to 8 (Mohs hardness), and the particle size range of the sandblasting particles is 80 mesh to 120 mesh.

[0059] As a possible implementation scheme, in step S2, the sandblasting particles include but are not limited to aluminum oxide sand, silicon carbide sand or glass beads; the impact pressure is 0.3 to 0.5 MPa, and the impact time is 2 to 4 minutes.

[0060] In the case of adopting the above technical solution, a microscopic concave pore structure is formed by the impact of hard sandblasting particles, which significantly increases the actual contact area; at the same time, the weak interface layer is removed, so that the wettability of the metal melt and the fiber surface is enhanced, the wetting angle θ is reduced, the surface energy is improved, and the mechanical interlocking effect and wettability are increased. The selected sandblasting particles must be materials with high hardness and stable chemical properties, including but not limited to aluminum oxide sand, silicon carbide sand or glass beads, with a hardness range of 5 to 8 (Mohs hardness) and a particle size range of 80 to 120 meshes, to ensure that a moderate roughness is generated during the sandblasting process, thereby enhancing the bonding force between the carbon fiber surface and the metal matrix. Too small a particle size (less than 80 meshes) will result in insufficient impact force and it is difficult to effectively increase the roughness; too large a particle size (greater than 120 meshes) may cause excessive erosion, damage the carbon fiber structure, and affect the interface bonding strength. The particle shape is preferably circular or approximately circular to ensure the uniformity of particle impact during sandblasting. The sandblasting pressure is 0.3-0.5MPa, which can ensure that the particle impact energy is sufficient to change the surface morphology without causing fiber breakage. The sandblasting time is 2-4 minutes, which can form a uniform surface roughness while avoiding excessive wear of the matrix. If the sandblasting time exceeds 4 minutes, the fiber surface may deteriorate in quality due to excessive wear, thereby affecting the final interface bonding performance. The above conditions can produce moderate roughness on the carbon fiber surface, improve the mechanical interlocking and wettability of the carbon fiber and the metal matrix, and thus significantly enhance the interface bonding performance.

[0061] As a possible implementation scheme, in step S3, in the intermediate structure of the stacked metal thin layers and the stacked reinforcing fibers, the number of the stacked metal thin layers and the stacked reinforcing fibers is 1 to 5.

[0062] In the case of the above technical solution, the number of stacked layers is 1 to 5, which can ensure the comprehensive balance of interface bonding quality, thermal conductivity and mechanical properties. With the increase of the number of superimposed layers, the interface bonding error will gradually accumulate. Too many layers may cause the interface roughness and wettability to decrease, and the interface bonding strength to weaken, thereby reducing the overall performance. In addition, according to Fourier's law of heat conduction, the increase in the number of superimposed layers will significantly increase the interface thermal resistance, thereby reducing the thermal conductivity of the composite material. In terms of mechanical properties, the stress transfer capacity of the composite structure depends on the volume fraction of carbon fiber. According to the mechanical model of composite materials, too high a volume fraction of carbon fiber leads to a decrease in material plasticity and stress concentration, affecting the overall structural stability. At the same time, each layer of stacking in the manufacturing process requires high-precision control, and too many layers will significantly increase the cumulative effect of processing errors. Therefore, limiting the number of metal thin layers and reinforcing fiber stacking to 1 to 5 can effectively achieve a balance between performance optimization and process controllability, and avoid performance degradation and process difficulties caused by excessive stacking.

[0063] As a possible implementation scheme, in step S5, the hot rolling process is performed 1 to 3 times, the single deformation is about 0.1 mm, the rolling pressure is controlled between 30 and 50 MPa, and the rolling temperature is controlled at 20 to 30°C below the melting point of the metal.

[0064] When the above technical solution is adopted, the total deformation can be 5% to 10% of the height of the composite material blank by controlling the number of rolling times, rolling pressure and rolling temperature. This can ensure the interface bonding performance of the composite material while avoiding interface defects or structural performance degradation caused by excessive deformation.

[0065] As a possible implementation scheme, in step S6, the heat treatment temperature is 180-680° C. and is kept at this temperature for 0.5-4 hours.

[0066] When the above technical solution is adopted, the heat treatment temperature range ensures the release of stress inside the metal matrix and promotes the diffusion of metal atoms at the interface; the holding time regulates the diffusion depth and ensures the uniformity of the interface bonding. Holding at 180-680°C for 0.5-4 hours can effectively avoid excessive generation of interface compounds (such as carbides) and oxidation or decomposition of carbon fibers, thereby optimizing the interface bonding characteristics and improving the overall performance of the composite material.

[0067] 3. Beneficial effects

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] (1) The present invention provides a fiber-reinforced metal matrix composite material, which significantly improves the mechanical properties of the composite material, especially in terms of tensile strength, shear strength and high temperature resistance. In addition, through the preparation method of the present invention, the composite material has better mechanical properties and meets the requirements for material durability and stability in high-performance applications.

[0070] (2) The present invention adopts a laying structure of long reinforcing fibers and metal thin layers, which effectively solves the problems of short carbon fiber knotting, agglomeration and uneven distribution in the melt in traditional processes. The use of continuous long fibers as reinforcements can ensure the uniform distribution and stability of the fibers in the metal matrix, thereby forming an optimized bonding structure at the metal-fiber interface. The composite laying structure further improves the interface bonding strength through a reasonable lamination method (such as parallel laying, cross laying, etc.), avoids the problems of weak interface bonding and interface defects in traditional processes, ensures the close bonding between the carbon fibers and the metal matrix, and thus improves the mechanical properties of the overall material.

[0071] (3) The present invention further optimizes the bonding strength between the metal thin layer and the carbon fiber through micro-deformation treatment and heat treatment process. The micro-deformation treatment makes the interface between the metal thin layer and the carbon fiber closer, and the heat treatment promotes metallurgical bonding and enhances the heat resistance and long-term stability of the composite material.

[0072] In summary, the present invention significantly improves the mechanical properties of metal-reinforced fiber composites through innovative interface design and process optimization, especially in terms of high load, shear resistance and high temperature resistance, meeting the application requirements of high-performance composites in complex working environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 The process flow chart of the preparation method of the present invention is as follows;

[0074] Figure 2 This is a structural schematic diagram of the carbon reinforced fiber laying method in Example 1;

[0075] Figure 3 This is a structural schematic diagram of the carbon reinforced fiber laying method in Example 2;

[0076] Figure 4 It is a structural schematic diagram of the carbon reinforced fiber laying method in Examples 3 and 4;

[0077] Figure 5 A schematic diagram of the working principle of a flow casting printing prototype machine of the flow casting printing method used in the present invention;

[0078] Figure 6 A magnified schematic diagram of the paving area for the flow casting printing prototype;

[0079] In the figure:

[0080] 1. Heating area; 11. Water outlet; 2. Laying area; 21. Laying platform; 3. Control area; 4. Metal melt. DETAILED DESCRIPTION

[0081] The present invention is further described below in conjunction with specific embodiments.

[0082] The flow casting printing method of the present application prepares an ultra-thin metal layer of 0.5 to 3 mm. The flow casting printing prototype developed by the applicant (recorded in "Research Progress of Carbon Fiber Reinforced Metal Matrix Composite Materials" in Volume 45, Issue 4 of "Shanghai Metal") can realize the formation of an ultra-thin metal layer. The structure of the flow casting printing prototype is shown in Figure 5 , 6 , including a heating zone 1 and a laying zone 2 thereon, and a control zone 3 electrically connected to the heating zone 1 and the laying zone 2, for controlling the operation of the heating zone 1 and the laying zone 2. The heating zone 1 is used to hold the molten metal 4 for heating to a molten state, and a water outlet 11 is arranged at the bottom for releasing the molten metal 4 to the laying zone 2 to form a thin metal layer; the workbench of the laying zone 2 is called a laying platform 21; the control zone 3 includes electrical components such as a PLC, a temperature control meter, and a stepper motor driver, and completes the normal operation of the heating zone 1 and the laying zone 2 by electrical control, including but not limited to controlling the heating of the heating zone 1, closing / releasing the molten metal at the water outlet 11, and moving the laying zone 2.

[0083] Example 1

[0084] A method for preparing a fiber-reinforced metal matrix composite material according to this embodiment, such as Figure 1 As shown, the following steps are included:

[0085] Step 1: Forming a thin layer of tin: Add metallic tin (Sn) to the heating zone 1 and heat it to above the melting point of tin to ensure that it is completely melted. Then, align the laying platform 21 below the water outlet 11 of the metallic tin, and start the control zone 3 to make the liquid tin flow out at a constant flow rate. As the laying platform 21 moves forward, the liquid tin is evenly laid on the surface of the laying platform 21, and quickly solidifies to form a uniform thin layer of tin with an average thickness of 0.92 mm. The process parameters are shown in Table 1.

[0086] Step 2: Laying carbon reinforced fiber process:

[0087] First, the carbon reinforced fiber is pretreated. This embodiment is a treatment for forming a recessed pore structure: silica sand is used to impact the surface of the carbon reinforced fiber to form a recessed pore structure, wherein the hardness grade of the silica sand is 5 to 8 (Mohs hardness), the particle size range of the silica sand is 80 mesh to 120 mesh, the pressure of the silica sand blasting is 0.3 to 0.5 MPa, and the time of the silica sand blasting is 2 to 4 minutes; through this silica sand blasting treatment, the oxide layer and other impurities that may exist on the surface of the carbon fiber can be effectively removed, and an appropriate roughness can be formed on its surface, so that the treated carbon fiber surface has a higher surface energy, thereby enhancing the bonding strength between the carbon fiber and the metal matrix, and the sand blasting pretreatment process helps to improve the interface bonding performance of the composite material and enhance the mechanical properties of the final composite material.

[0088] Then, the pretreated carbon reinforced fibers are uniformly laid in parallel on the upper surface of the tin thin layer formed in step 1 to form a tin thin layer-carbon reinforced fiber structure. The carbon reinforced fibers can be laid parallel to the length or width of the tin thin layer, or can be laid obliquely to the length and width of the tin thin layer. The maximum length of the carbon reinforced fibers is the length of the diagonal line of the upper surface of the tin thin layer, such as Figure 2 As shown, in this embodiment, each carbon fiber has an equal width, a length equal to the length of the tin thin layer, and a fiber direction and a 0° angle with the surface of the tin thin layer. The coverage of the carbon fiber is 30%. This density range usually helps to improve the tensile strength and bending resistance of the composite material, and can effectively avoid excessive fiber agglomeration or shedding problems, ensuring uniform distribution of the carbon fiber in the tin thin layer and good bonding strength.

[0089] Step 3, process of forming a composite material blank: transfer the tin thin layer-carbon reinforced fiber structure formed in step 2 to the laying area 2: first, place the tin thin layer-carbon reinforced fiber structure on the laying platform 21 to ensure its stability. Then, adjust the laying platform 21 to below the tin melt outlet 11. When starting the laying, the tin melt flows out at a constant flow rate through the circuit control of the control area. The laying platform 21 moves forward quickly, and the tin melt evenly covers the surface of the carbon fiber layer, combining with the tin thin layer to form a uniform tin thin layer. This process should ensure that the tin melt completely covers the carbon fiber while avoiding displacement or damage to the carbon fiber. As the tin melt is laid on the surface of the carbon fiber layer, the tin layer solidifies rapidly to form a composite structure of tin-carbon fiber-tin.

[0090] Step 4, micro-deformation process: Place the tin-carbon fiber-tin composite structure prepared in step 3 on a hot rolling mill, adjust the rolling temperature at 210°C, and adjust the rolling pressure to 30MPa. When rolling begins, ensure that the composite structure is evenly stressed along the rolling direction during each rolling process. The hot rolling process is performed once, with a single deformation of about 0.1mm, and the overall deformation is controlled at 5% to 10% of the height of the composite material.

[0091] Step 5, heat treatment process: heat treat the composite structure after micro-deformation in step 4 to promote the formation of a good interface between tin and carbon fiber: put the composite structure into a heat treatment furnace, adjust the furnace temperature to 210℃ and keep it for 0.5 hours to ensure stable heating of the composite structure. After the heat treatment is completed, take out the composite material and cool it naturally to room temperature.

[0092] Example 2

[0093] A method for preparing a fiber-reinforced metal matrix composite material according to this embodiment, such as Figure 1 As shown, the following steps are included:

[0094] Step 1: Forming a thin layer of zinc alloy: Add zinc alloy No. 3 (Zamak 3) to the heating zone 1 and heat it to 550°C to ensure that the zinc alloy is completely melted. Then, align the laying platform 21 below the outlet 11 of the zinc alloy, and control the liquid zinc alloy to flow out at a constant flow rate through the control zone 3. As the laying platform 21 moves forward, the liquid zinc alloy is evenly laid on the surface of the platform and quickly solidifies to form a uniform zinc alloy thin layer with an average thickness of 1.77 mm. The process parameters are shown in Table 1. The composition of zinc alloy No. 3 is shown in the following table.

[0095] No. 3 zinc alloy aluminum copper magnesium iron lead cadmium tin Zinc Zamak 3 3.8～4.3％ <0.030％ 0.035～0.06％ <0.020％ <0.003％ ≤0.003％ <0.001％ margin

[0096] Step 2: Laying carbon reinforced fiber process:

[0097] First, the carbon reinforced fiber is pretreated. In this embodiment, a nickel plating layer is formed and then a concave hole structure is formed.

[0098] Nickel plating: The surface of the carbon fiber is electroplated with nickel. The electroplating process uses a nickel sulfate solution and the electroplating current density is set to 3A / dm 2 The electroplating time is 12 minutes and the coating thickness is controlled at 10μm. During the electroplating process, the solution temperature is maintained between 50℃ and 60℃ to ensure the uniformity and stability of the electroplating process. The nickel coating can effectively increase the roughness and adhesion of the carbon fiber surface, significantly enhance the bonding force between the carbon fiber and the metal thin layer, and provide better interface conditions for the subsequent laying of the metal melt, thereby improving the mechanical properties of the metal-carbon fiber composite material.

[0099] Treatment for forming a sunken pore structure: Silica sand is used to impact the surface of the nickel-plated carbon reinforced fiber to form a sunken pore structure, wherein the hardness grade of the silica sand is 5 to 8 (Mohs hardness), the particle size range of the silica sand is 80 mesh to 120 mesh, the pressure of the silica sand blasting is 0.3 to 0.5 MPa, and the time of the silica sand blasting is 2 to 4 minutes.

[0100] Then, the pretreated carbon reinforced fibers are uniformly cross-laid on the upper surface of the zinc alloy thin layer formed in step 1 to form a zinc alloy thin layer-carbon reinforced fiber structure, such as Figure 3 As shown in the figure, carbon reinforced fibers are laid parallel to the length and width of the zinc thin layer, and the angle between each carbon fiber and the zinc thin layer surface is 0°. The coverage of carbon fiber is 50%, and this density range usually helps to improve the tensile strength and bending resistance of the composite material, while effectively avoiding excessive fiber agglomeration or shedding problems, ensuring uniform distribution of carbon fiber in the zinc alloy thin layer and good bonding strength.

[0101] Step 3, process of forming a composite material blank: transfer the zinc alloy thin layer-carbon reinforced fiber structure formed in step 2 to the laying area. First, place the zinc alloy thin layer-carbon reinforced fiber structure on the laying platform 21 to ensure its stability. Then, adjust the laying platform 21 to below the zinc alloy melt outlet 11. When starting the laying, the control area 3 allows the zinc alloy melt to flow out at a constant flow rate. The laying platform 21 moves forward quickly, and the zinc alloy melt evenly covers the surface of the carbon fiber layer, combining with the zinc alloy thin layer to form a uniform zinc alloy thin layer. This process should ensure that the zinc alloy melt completely covers the carbon fiber while avoiding displacement or damage to the carbon fiber. As the zinc alloy melt is laid on the surface of the carbon fiber layer, the zinc alloy layer solidifies rapidly to form a composite structure of zinc alloy-carbon fiber-zinc alloy.

[0102] Step 4: Micro-deformation process: Place the composite structure prepared in step 3 on a hot rolling mill, adjust the rolling temperature to 355°C, and adjust the rolling pressure to 30MPa. When rolling begins, ensure that the composite structure is evenly stressed along the rolling direction during each rolling process. The hot rolling process is performed twice, with a single deformation of about 0.1mm, and the overall deformation is controlled within 5% to 10% of the height of the composite material.

[0103] Step 5: Heat treatment process: Heat treat the composite structure after micro-deformation in step 4, adjust the heat treatment temperature to 355°C and maintain it for 2 hours to promote the formation of a good interface between the zinc alloy and the carbon fiber. After the heat treatment is completed, take the composite material out of the furnace and cool it naturally to room temperature.

[0104] Example 3

[0105] A method for preparing a fiber-reinforced metal matrix composite material according to this embodiment, such as Figure 1 As shown, the following steps are included:

[0106] Step 1: Forming a thin layer of aluminum alloy: Add A356 aluminum alloy to the heating zone 1 and heat it to 650°C to ensure that it is completely melted. Subsequently, align the laying platform 21 below the outlet 11 of the liquid A356 aluminum alloy, and start the control zone 3 to make the liquid aluminum alloy flow out at a constant flow rate. The laying platform 21 moves forward, and the liquid aluminum alloy is evenly laid on the surface of the platform, and quickly solidifies to form a uniform thin layer of aluminum alloy with a thickness of about 1.51 mm. The process parameters are shown in Table 1. The composition of A356 aluminum alloy is as follows:

[0107] Si Mg Fe Cu Zn Mn Ti Other impurities Al 6.5-7.5％ 0.25-0.45％ 0.13％ 0.1％ 0.05％ 0.05％ 0.2％ <0.15％ margin

[0108] Step 2: Laying carbon reinforced fiber process:

[0109] First, the carbon reinforced fiber is pretreated. In this embodiment, a copper plating layer is formed and then a recessed hole structure is formed.

[0110] Treatment for forming a copper plating layer: Place the carbon fiber in an electroplating tank containing a copper salt solution, and apply electricity to reduce the copper ions and deposit them on the surface of the carbon fiber. The electroplating current density is set to 2A / dm 2 The copper plating time is 25 minutes, and the copper plating thickness is controlled at 10μm. During the electroplating process, the solution temperature is maintained between 40℃ and 50℃ to ensure uniform deposition and stable coating quality. The copper plating treatment can significantly improve the adhesion and roughness of the carbon fiber surface, provide good interface conditions for the subsequent laying of the metal melt, enhance the bonding force between the metal and the carbon fiber, and thus improve the mechanical properties and interface strength of the composite material.

[0111] Treatment for forming a sunken hole structure: Silica sand is used to impact the copper-plated carbon reinforced fiber surface to form a sunken hole structure, wherein the hardness grade of the silica sand is 5 to 8 (Mohs hardness), the particle size range of the silica sand is 80 mesh to 120 mesh, the pressure of the silica sand blasting is 0.3 to 0.5 MPa, and the time of the silica sand blasting is 2 to 4 minutes.

[0112] Then, the pretreated carbon reinforced fibers are uniformly cross-laid on the upper surface of the aluminum alloy thin layer formed in step 1 to form a zinc alloy thin layer-carbon reinforced fiber structure, such as Figure 4 As shown, in this embodiment, the carbon reinforced fibers are laid parallel to the length and width directions of the aluminum alloy thin layer, and are also laid parallel to the length and width directions of the aluminum alloy thin layer at an angle of 0° to the surface of the tin thin layer. The coverage of the carbon fibers is 70%.

[0113] Step three, forming a composite material blank process: transfer the aluminum alloy thin layer-carbon reinforced fiber structure formed in step two to the laying area. First, place the zinc alloy thin layer-carbon reinforced fiber structure on the laying platform 21 to ensure its stability. Then, adjust the laying platform to below the aluminum alloy melt outlet 11. When starting the laying, the control area 3 allows the aluminum alloy melt to flow out at a constant flow rate. The laying platform 21 moves forward quickly, and the aluminum alloy melt evenly covers the surface of the carbon fiber layer, combining with the aluminum alloy thin layer to form a uniform aluminum alloy thin layer. This process should ensure that the aluminum alloy melt completely covers the carbon fiber while avoiding displacement or damage to the carbon fiber. As the aluminum alloy melt is laid on the surface of the carbon fiber layer, the aluminum alloy layer solidifies rapidly to form a composite structure of aluminum alloy-carbon fiber-aluminum alloy.

[0114] Step 4: Micro-deformation process: Place the composite structure prepared in step 3 on a hot rolling mill, adjust the rolling temperature to 535°C, and adjust the rolling pressure to 30MPa. When rolling begins, ensure that the composite structure is evenly stressed along the rolling direction during each rolling process. The hot rolling process is performed once, with a single deformation of about 0.1mm, and the overall deformation is controlled within 5% to 10% of the height of the composite material.

[0115] Step 5, heat treatment process: heat treat the composite structure after micro-deformation in step 4 to promote the formation of a good interface between the aluminum alloy and the carbon fiber. Put the aluminum alloy composite material with carbon fiber laid into the heat treatment furnace, adjust the furnace temperature to 535℃ and keep it for 3 hours to ensure stable heating of the composite structure. After the heat treatment is completed, take out the composite material and cool it naturally to room temperature.

[0116] Example 4

[0117] A method for preparing a fiber-reinforced metal matrix composite material according to this embodiment, such as Figure 1 As shown, the following steps are included:

[0118] Step 1: Forming a thin layer of zinc alloy: Add zinc alloy No. 3 to the heating zone 1 and heat it to 550°C to ensure that it is completely melted. Subsequently, align the laying platform below the outlet 11 of the liquid zinc alloy No. 3, and control the control zone 3 to make the liquid zinc alloy flow out at a constant flow rate. The laying platform 21 moves forward, and the liquid zinc alloy is evenly laid on the surface of the platform, and quickly solidifies to form a uniform zinc alloy thin layer with a thickness of about 1.79 mm. The process parameters are shown in Table 1. The composition of zinc alloy No. 3 is as follows:

[0119]

[0120] Step 2: Laying carbon reinforced fiber process:

[0121] First, the carbon reinforced fiber is pretreated. In this embodiment, a nickel plating layer is formed and then a concave hole structure is formed.

[0122] Nickel plating: The surface of the carbon fiber is electroplated with nickel. The electroplating process uses a nickel sulfate solution and the electroplating current density is set to 3A / dm 2 The electroplating time is 12 minutes and the coating thickness is controlled at 10μm. During the electroplating process, the solution temperature is maintained between 50℃ and 60℃ to ensure the uniformity and stability of the electroplating process. The nickel coating can effectively increase the roughness and adhesion of the carbon fiber surface, significantly enhance the bonding force between the carbon fiber and the metal thin layer, and provide better interface conditions for the subsequent laying of the metal melt, thereby improving the mechanical properties of the metal-carbon fiber composite material.

[0123] Treatment for forming a sunken pore structure: Silica sand is used to impact the surface of the nickel-plated carbon reinforced fiber to form a sunken pore structure, wherein the hardness grade of the silica sand is 5 to 8 (Mohs hardness), the particle size range of the silica sand is 80 mesh to 120 mesh, the pressure of the silica sand blasting is 0.3 to 0.5 MPa, and the time of the silica sand blasting is 2 to 4 minutes.

[0124] Then, the pretreated carbon reinforced fibers are uniformly cross-laid on the upper surface of the zinc alloy thin layer formed in step 1 to form a zinc alloy thin layer-carbon reinforced fiber structure, such as Figure 3 As shown, in this embodiment, the carbon reinforced fibers are laid parallel to the length and width directions of the zinc alloy thin layer, and the angle between each carbon fiber and the surface of the zinc alloy thin layer is 0°. The coverage of the carbon fibers is 70%.

[0125] Step 3: Forming a multilayer structure: Repeat steps 1 and 2 multiple times on the zinc alloy thin layer-carbon reinforced fiber structure formed in step 2. In this embodiment, repeat steps 3 times to form an intermediate structure of a metal thin layer and reinforced fiber stacking.

[0126] Step 4, process of forming a composite material blank: transfer the intermediate structure formed in step 3 to the laying area. First, place the intermediate structure on the laying platform to ensure its stability. Then, adjust the laying platform 21 to below the outlet of the zinc alloy melt. When starting the laying, allow the zinc alloy melt to flow out at a constant flow rate. The laying platform 21 moves forward quickly, and the zinc alloy melt evenly covers the surface of the carbon fiber layer, combining with the zinc alloy thin layer to form a uniform zinc alloy thin layer. This process should ensure that the zinc alloy melt completely covers the carbon fiber while avoiding displacement or damage to the carbon fiber. As the zinc alloy melt is laid on the surface of the carbon fiber layer, the zinc alloy layer solidifies rapidly. A composite structure of zinc alloy-carbon fiber-zinc alloy-carbon fiber-zinc alloy-carbon fiber-zinc alloy is formed.

[0127] Step 5, micro-deformation process: Place the composite structure prepared in step 4 on a hot rolling mill, adjust the rolling temperature at 535°C, and adjust the rolling pressure to 30MPa. When rolling begins, ensure that the composite structure is evenly stressed along the rolling direction during each rolling process. The hot rolling process is performed once, with a single deformation of about 0.4mm, and the overall deformation is controlled within 5% to 10% of the height of the composite material.

[0128] Step 6: Heat treatment process: Heat treat the composite structure after micro-deformation in step 5 to promote the formation of a good interface between the zinc alloy and the carbon fiber. Put the zinc alloy composite material with laid carbon fiber into the heat treatment furnace, adjust the furnace temperature to 535℃ and keep it for 3 hours to ensure stable heating of the composite structure. After the heat treatment is completed, take out the composite material and cool it naturally to room temperature.

[0129] Table 1 Process parameters of the casting printing method for forming the metal thin layer in each embodiment

[0130]

[0131] From Table 1, the theoretical thickness of the metal thin layer of the present application is calculated using formula (1):

[0132]

[0133] The specific advantages are:

[0134] (1) Innovative integration of multi-physics coupling models: This invention proposes for the first time a metal thin layer thickness prediction formula (1) based on a flow-solidification coupling physical model, breaking through the limitations of traditional single process analysis. Formula (1) achieves accurate prediction of the entire physical field of thin layer thickness formation by dynamically coupling the flow process of the metal melt (affected by viscosity μ and substrate speed v2) and the solidification process (affected by thermal diffusivity α and substrate height h). Compared with the prior art methods that only rely on empirical adjustments or isolated consideration of a single parameter, this invention significantly improves the accuracy of thickness prediction and solves the problem of thickness fluctuations caused by insufficient parameter coupling in traditional processes.

[0135] (2) Dimensional analysis ensures the rigor and universality of the formula: Through strict dimensional balance analysis, formula (1) is completely self-consistent in physical units, eliminating the systematic errors caused by dimensional mismatch in traditional empirical formulas. The power relationship of each parameter (such as μ, ρ, v2, α, h) is derived based on the physical essence, ensuring its universality under different metal materials and process conditions. For example, the formula can be accurately adapted to the preparation of thin layers of various metals such as tin, aluminum, and zinc. The average deviation between the measured thickness and the theoretical prediction value is within 8% (see the data of Examples 1-4), which verifies its scientificity and reliability.

[0136] (3) Real-time optimization capability of dynamically responding to process parameters: It can dynamically reflect the synergistic effect of substrate movement speed (v2) and melt viscosity (μ), providing a theoretical basis for real-time regulation of process parameters. Experiments show that when the substrate speed increases from 1m / s to 3m / s, the thickness reduction predicted by the formula is highly consistent with the actual measured value. This feature makes the present invention have important practical application prospects in experimental research, especially in future industrial production. By adjusting parameters such as v2 and h in real time, it is possible to achieve online precise control of the thickness of the metal thin layer, thereby improving production efficiency and product quality consistency;

[0137] (4) Correction coefficient adaptation for accurate prediction of multi-metal materials: In view of the differences in physical properties of different metal materials, the present invention introduces a correction coefficient k to further improve the prediction accuracy of the formula. The correction coefficient is associated with physical parameters (such as viscosity, density, and thermal diffusivity) through experimental calibration to ensure the adaptability of the formula to materials such as tin, zinc alloy, and aluminum alloy. For example, in Example 2 (zinc alloy), k=1.36, and in Example 3 (aluminum alloy), k=1.11. The deviation between the corrected theoretical thickness and the actual thickness is less than 8%. This design is significantly better than the "one-size-fits-all" empirical model in the prior art and solves the prediction problem in multi-material scenarios;

[0138] (5) Significantly reduce the cost of trial and error and process development cycle: Traditional metal thin layer preparation requires repeated experiments to determine process parameters, which is time-consuming and material-consuming. The present invention can directly infer the optimal process parameters (such as v2, h, temperature) based on the target thickness through the parameterized prediction ability of the formula, reducing the number of trial and error by more than 50% (see the comparative analysis of comparative examples 1-3 and the embodiments). For example, in Example 4, the parameters are optimized through the formula to achieve the precise preparation of 8.42mm composite material blanks in one go, shortening the process development cycle by 30% compared with traditional methods, significantly improving production efficiency and economy.

[0139] (6) Provide theoretical support for the preparation of ultra-thin metal-based composite materials: The formula of the present invention is particularly outstanding in the preparation of ultra-thin metal layers (0.5-3 mm). By precisely controlling the synergistic relationship between the thickness of the metal thin layer and the fiber distribution density (such as the thickness of the tin thin layer in Example 1 is 0.92 mm), fiber agglomeration and interface defects are effectively avoided, and the tensile strength of the composite material is increased by 17% to 30% (compared with Comparative Examples 1-3). This technological breakthrough provides core process theoretical support for the demand for lightweight, high-strength composite materials in the fields of aerospace, new energy vehicles, etc.

[0140] In summary, the metal thin layer thickness prediction formula of the present invention realizes the scientific, precise and efficient metal thin layer preparation process through multi-physical field coupling modeling, dimensional analysis, dynamic parameter response and correction coefficient design, and solves the key problems in the prior art such as thickness control relying on experience, poor adaptability of multiple materials, and long process development cycle.

[0141] Comparative Example 1

[0142] The preparation method of a fiber-reinforced metal matrix composite material in this comparative example is basically the same as that in Example 1, the main difference is that the laying length of each carbon fiber in Comparative Example 1 is 1 / 6 of the length of the metal thin layer, that is, short fibers are used for laying.

[0143] Comparative Example 2

[0144] The preparation method of a fiber-reinforced metal matrix composite material in this comparative example is basically the same as that in Example 1, the main difference is that in Comparative Example 2, carbon fibers are not laid on the surface of the tin thin layer.

[0145] Comparative Example 3

[0146] The preparation method of a fiber-reinforced metal matrix composite material in this comparative example is basically the same as that in Example 1, except that the carbon-reinforced fiber in Comparative Example 3 is not pretreated.

[0147] Performance Testing

[0148] 1. Tensile strength

[0149] Test standard: Tensile test is carried out according to ASTM E8 / E8M standard.

[0150] Testing equipment: The tensile test was carried out using a JITAI-universal tensile testing machine.

[0151] Sample preparation: The sample is rectangular with a size of 50 mm in length and 20 mm in width. Ensure that the surface of the sample is flat and has no obvious defects.

[0152] Test steps:

[0153] Clamp the specimen in the testing machine and ensure that the loading direction is consistent with the specimen axis.

[0154] The test was carried out at a constant tensile rate of 2 mm / min until the specimen broke.

[0155] The stress-strain curve was recorded and analyzed, and the tensile strength was calculated by dividing the maximum load by the original cross-sectional area of ​​the specimen.

[0156] 2. Shear strength

[0157] Test standard: According to ASTM D5379, the V-notched beam method is used to measure the shear properties of composite materials.

[0158] Test equipment: Use a double shear test fixture.

[0159] Sample preparation: The shear surface of the specimen is parallel to the fiber laying direction.

[0160] Test steps:

[0161] Place the specimen in the test fixture, ensuring that the shear plane is consistent with the loading direction.

[0162] The load was applied at a constant loading rate of 1 mm / min until the specimen failed in shear.

[0163] The maximum shear load was recorded and divided by the shear area to calculate the shear strength.

[0164] 3. Yield Strength

[0165] Test standard: Based on ASTM E8 / E8M standard, determined by the stress-strain curve of the tensile test.

[0166] Test equipment: Use JITAI-universal tensile testing machine.

[0167] Sample preparation: The specimen size is consistent with the tensile strength test.

[0168] Test steps:

[0169] A standard tensile test was performed and the stress-strain curve was recorded.

[0170] The yield strength is calculated using the 0.2% offset method, that is, on the stress-strain curve, the stress value corresponding to the intersection of the curve is shifted 0.2% to the right along the strain axis, and the yield strength is obtained.

[0171] 4. Fatigue strength

[0172] Test standard: According to ASTM E466 standard, axial tension-tension fatigue test is carried out using a high-frequency fatigue testing machine.

[0173] Test equipment: MTS 810 high frequency fatigue testing machine was used.

[0174] Sample preparation: The specimen size is consistent with the tensile strength test.

[0175] Test steps:

[0176] Set the stress ratio R=0.1, the frequency to 10 Hz, and the number of cycles to 10 6 Second-rate.

[0177] The fatigue test is carried out under the above conditions until the specimen breaks or the set number of cycles is reached.

[0178] Fatigue strength is defined as the 6 The maximum stress amplitude after cycles without fracture.

[0179] 5. Hardness

[0180] Test standard: According to ASTM E10 standard, the test is carried out using a Brinell hardness tester.

[0181] Test equipment: Wilson 3000 Brinell hardness tester was used for testing.

[0182] Sample preparation: The sample surface needs to be polished before testing to ensure it is flat and free of defects.

[0183] Test steps:

[0184] Select appropriate load and carbide indenter according to different metal substrates, and the holding time is 15 seconds.

[0185] Five different areas were selected on the surface of the sample for measurement, and the average value was taken as the final result.

[0186] 6. Impact strength

[0187] Test standard: According to ASTM E23 standard, the impact test of unnotched specimens was carried out using a Charpy impact tester.

[0188] Testing Equipment: A Tinius Olsen 84 Charpy impact tester was used.

[0189] Sample preparation: The sample size is consistent with the tensile strength test, and the impact direction is perpendicular to the fiber laying plane.

[0190] Test steps:

[0191] Place the specimen in the testing machine and ensure that the impact direction is perpendicular to the fiber laying plane.

[0192] A specified impact energy is applied and the energy absorbed is recorded.

[0193] Impact strength is calculated by dividing the impact absorbed energy by the cross-sectional area of ​​the specimen.

[0194] Table 2 Performance test results of composite materials obtained in various embodiments and comparative examples

[0195]

[0196] in conclusion:

[0197] 1. Comparison of Example 1 (Sn substrate) with Comparative Examples 1, 2, and 3

[0198] Example 1 significantly improves the mechanical properties of the composite material by combining the uniform laying of long fibers, interface strengthening (sandblasting) and micro-deformation process. Compared with Comparative Example 1 (short fiber laying), the tensile strength of Example 1 is 55MPa, which is about 17% higher than the 47MPa of Comparative Example 1. This improvement is attributed to the higher load transfer efficiency brought about by the uniform laying of long fibers, which avoids the agglomeration phenomenon that may occur when short fibers are laid, thereby effectively enhancing the load transfer capacity between the fiber and the matrix, and significantly improving the tensile strength and shear strength of the material. Compared with Comparative Example 2 (unlaid fibers), the improvement in tensile strength of Example 1 reaches about 31%, which shows that the introduction of carbon fibers directly enhances the mechanical properties of composite materials, especially in applications with high strength requirements. In terms of interface strengthening, Example 1 enhances the mechanical interlocking effect between carbon fibers and metal matrix through sandblasting process, and improves the interface bonding strength. Compared with Comparative Example 3 (unpretreated), the interface bonding force of Example 1 is stronger, and the tensile strength and shear strength are increased by about 15% and 35%, respectively. This improvement shows that interface optimization not only improves the adhesion between fiber and matrix, but also enhances the load transfer efficiency, reduces stress concentration, and further improves the overall mechanical properties of the composite material.

[0199] 2. Comparison between Example 2 (Zn alloy substrate) and Example 4 (multilayer Zn alloy substrate)

[0200] The multilayer structure of Example 4 significantly improves fatigue strength from 172MPa in Example 2 to 190MPa. The multilayer structure optimizes the stress dispersion mechanism and reduces stress concentration through the synergy between layers, thereby enhancing the stability of the material under repeated loads and significantly extending the fatigue life. In contrast, the single-layer structure of Example 2 failed to effectively disperse the load, resulting in its lower fatigue strength.

[0201] In terms of impact resistance, the impact strength of Example 4 is 52 J, which is significantly higher than 45 J of Example 2. The multilayer structure enhances the energy absorption capacity of the material under impact load and reduces local damage by optimizing interface bonding and metallurgical stability. The single-layer structure of Example 2 has poor impact resistance due to uneven energy transfer and exhibits low impact strength.

[0202] In addition, the multilayer structure of Example 4 maintains good static performance while improving fatigue strength and impact resistance. The combination of each layer of metal and fiber, through interlayer synergy, makes the composite material have higher stability and reliability under complex working conditions.

[0203] Although the tensile strength of Example 2 (315 MPa) is slightly higher than that of Example 4 (300 MPa), the difference is not significant in practical applications. In particular, the multilayer structure of Example 4 shows obvious advantages in terms of dynamic performance and fatigue resistance. The multilayer structure provides better comprehensive mechanical properties under high load conditions by optimizing stress dispersion and interface bonding.

[0204] 3. Comparison of Example 3 (Aluminum Alloy Matrix)

[0205] In Example 3, after the introduction of carbon fiber, the tensile strength is increased to 340MPa, which shows a 30% increase compared to the tensile strength of pure aluminum alloy (280MPa). The high strength and high modulus characteristics of carbon fiber effectively enhance the bearing capacity of the composite material. At the same time, by optimizing the interface bonding, the load transfer efficiency is improved, the stress concentration is reduced, and the fatigue strength of the composite material is further improved, and the fatigue strength is increased from 32MPa to 37MPa. On the other hand, the impact strength of the carbon fiber reinforced composite material in Example 3 is increased to 25J, which shows a significant improvement compared to 12J of pure aluminum alloy. This improvement is attributed to the enhancement of the energy absorption capacity of the material and the improvement of the interface bonding force after the introduction of carbon fiber. The addition of carbon fiber also significantly improves the high temperature stability of the composite material, avoiding the strength drop of pure aluminum alloy due to thermal expansion differences under high temperature environment. Overall, the introduction of carbon fiber enables the composite material to show excellent comprehensive performance under complex working conditions such as high strength, high fatigue, impact resistance and high temperature, and is suitable for high-end application fields such as aerospace and automobiles.

[0206] Although the present invention has been described in detail above by means of general description, specific implementation methods and tests, it is obvious to those skilled in the art that some modifications or improvements may be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A fiber-reinforced metal matrix composite material, characterized in that: It is a plate-like structure with a length of a, a width of b, and a thickness of at least 7 mm, comprising a plurality of stacked metal thin layers, and reinforcing fibers are laid between adjacent metal thin layers, wherein the length of the reinforcing fibers is less than or equal to (a 2 +b 2 ) 1 / 2 The reinforcing fiber surface is distributed with a recessed hole structure, wherein the thickness of the metal thin layer is 0.5 to 3 mm.

2. A fiber-reinforced metal matrix composite material according to claim 1, characterized in that: The laying area of ​​the reinforcing fiber accounts for 30 to 70% of the area of ​​the metal thin layer.

3. The fiber-reinforced metal matrix composite material according to claim 1, characterized in that: The surface of the reinforcing fiber is coated with a coating, which is a nickel layer or a copper layer, and an intermetallic compound M-Ni exists between the reinforcing fiber and the metal thin layer. x or M-Cu x , wherein M is the metal type of the metal thin layer, x>0, and the thickness of the coating is 0.003mm to 0.015mm.

4. The fiber-reinforced metal matrix composite material according to claim 1, characterized in that: The reinforcing fibers are carbon fibers or metal fibers.

5. A fiber-reinforced metal matrix composite material according to any one of claims 1 to 4, characterized in that: The metal types of the metal thin layer are Sn, Zn, Al and alloys thereof.

6. A method for preparing a fiber-reinforced metal matrix composite material according to any one of claims 1 to 5, characterized in that: include: S1, metal thin layer forming process: using flow casting printing method to prepare a single metal thin layer with a thickness of 0.5 to 3 mm; S2, a step of laying reinforcing fibers: laying reinforcing fibers on the metal thin layer formed in step S1 to form a metal thin layer-reinforcing fiber structure; S3, forming a multilayer structure process: on the metal thin layer-reinforcement fiber structure formed in step S2, repeat steps S1 to S2 N times, N ≥ 0, to form an intermediate structure of metal thin layer and reinforcement fiber stacking; S4, forming a composite material blank process: on the surface of the reinforcing fiber of the intermediate structure in step S3, a metal thin layer with a thickness of 0.5 to 3 mm is prepared by a flow casting printing method to form a composite material blank; S5, micro deformation process: hot rolling process is adopted for the composite material blank of step S4, and the deformation amount is controlled to be 5% to 10% of the height of the composite material blank; S6, heat treatment process: heat treatment is performed on the composite material blank after the micro-deformation in step S5 to obtain a fiber-reinforced metal matrix composite material; The flow casting printing method is performed using a flow casting printing prototype machine, which comprises a heating area (1), a laying area (2) located below the heating area (1), and a control area (3): A metal melt (4) is placed in a heating zone (1) for heating to a molten state, and a water outlet (11) is provided at the bottom for releasing the metal melt (4) to a laying zone (2) to form a metal thin layer; the laying zone (2) includes a laying platform (21); a control zone (3) is electrically connected to the heating zone (1) and the laying zone (2) and is used to control the operation of the heating zone (1) and the laying zone (2), including but not limited to controlling the heating of the heating zone (1), closing / releasing the melt at the water outlet (11), and moving the laying zone (2).

7. The method for preparing a fiber-reinforced metal matrix composite material according to claim 6, characterized in that: In the casting printing method of step S1 and step S4, the thickness d of the metal thin layer satisfies formula (1): Wherein, d is the thickness of the metal thin layer, v2 is the moving speed of the laying platform (21), h is the height of the water outlet (11) from the laying platform (21), η is the viscosity of the metal melt (4); ρ is the density of the metal melt (4), α is the thermal diffusivity of the metal melt (4), and k is the correction coefficient of the metal melt (4), and the correction coefficients are different for different metals.

8. The method for preparing a fiber-reinforced metal matrix composite material according to claim 7, characterized in that: In the casting printing method of step S1 and step S4, the casting temperature of the metal melt is 180 to 680° C., and the moving speed of the laying platform is 1 to 3 m / s.

9. The method for preparing a fiber-reinforced metal matrix composite material according to claim 6, characterized in that: Step S2 includes pretreatment of the reinforcing fibers. The purpose of the pretreatment is to optimize the surface properties of the carbon fibers and significantly enhance the interfacial bonding performance between the carbon fibers and the metal melt. The pretreatment is performed by the following method: Treatment for forming a concave hole structure: using sandblasting particles to impact the surface of the reinforcing fiber to form a concave hole structure, wherein the hardness level of the sandblasting particles is 5 to 8, and the particle size range of the sandblasting particles is 80 mesh to 120 mesh; or, S21. Treatment for forming a coating: forming a nickel layer or a copper layer on the surface of the reinforcing fiber; by forming a transition layer between metals, the chemical bond strength and wettability of the interface are improved; S22, a process for forming a sunken hole structure: using sandblasting particles to impact the surface of the reinforcing fiber covered with the nickel layer or the copper layer in step S21 to form a sunken hole structure, wherein the hardness grade of the sandblasting particles is 5 to 8, and the particle size range of the sandblasting particles is 80 mesh to 120 mesh.

10. The method for preparing a fiber-reinforced metal matrix composite material according to claim 6, characterized in that: In step S2, the sandblasting particles include but are not limited to alumina sand, silicon carbide sand or glass beads; the impact pressure is 0.3-0.5Mpa, and the impact time is 2-4 minutes; in step S3, in the intermediate structure of the metal thin layer and the reinforcing fiber stack, the number of the metal thin layer and the reinforcing fiber stack is 1-5; in step S5, the number of rolling times of the hot rolling process is 1 to 3 times, the single deformation is about 0.1mm, the rolling pressure is controlled between 30 and 50MPa, and the rolling temperature is controlled at 20-30°C below the melting point of the metal; in step S6, the heat treatment temperature is 180-680°C, and is kept at this temperature for 0.5-4 hours.

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