Carbon fiber composite aluminum alloy and preparation method and application thereof

Abstract

The invention provides a carbon fiber composite aluminum alloy and a preparation method and application thereof. The preparation method comprises the steps that an aluminum alloy plate is provided, and the aluminum alloy plate is provided with a first surface and a second surface which are oppositely arranged; performing laser treatment on the first surface and / or the second surface of the aluminum alloy plate to activate the first surface and / or the second surface to obtain a first activated plate with an activated surface; modifying the activated surface of the first activated plate by adopting a coupling agent to obtain a second activated plate with a modified surface; and the carbon fiber composite material is attached to the modified surface of the second activated plate, a carbon fiber composite layer is formed through compounding, and then the carbon fiber composite aluminum alloy is obtained. Based on the technology of combining laser surface treatment and coupling agent modification, fine microstructure modification is carried out on the surface of the aluminum alloy, and the effect of enhancing the overall performance of the composite material is achieved.

Description

Technical Field

[0001] This invention relates to the field of composite materials, and more specifically, to a carbon fiber composite aluminum alloy, its preparation method, and its application. Background Technology

[0002] Since its development began in the mid-20th century, composite materials have seen increasingly widespread applications in aerospace, automotive, sporting goods, and many other fields, becoming an indispensable material in modern industry. Fiber-metal Laminate (FML) structures, in particular, are considered ideal for future high-performance load-bearing structures due to their combination of the rigidity and toughness of metallic materials with the lightweight and high-strength properties of polymer-based composites. However, the performance of composite materials depends not only on the properties of the matrix and reinforcing fibers, but more importantly on the interaction and bonding strength of the interfaces between them. This issue is particularly prominent for the interface of aluminum alloy and carbon fiber composites, becoming a key bottleneck limiting their application effectiveness.

[0003] CN111020685A discloses a method for preparing fiber-reinforced metal laminates to improve interlayer strength. This method involves electro-etching the surface of a titanium alloy to form a nanoscale porous structure. The titanium alloy surface treated with this process exhibits high roughness and good wettability, enabling excellent adhesion to epoxy resin and forming a strong interface layer and strong mechanical bond, resulting in high bonding strength between the titanium alloy and epoxy resin. However, this technique employs chemical processing, requiring precise solution preparation, and cannot achieve customized surface treatment. Furthermore, this technology can only achieve uniform treatment of the entire surface by changing the process, and cannot perform specialized reinforcement treatment on specific locations. Additionally, chemical etching is not suitable for large-size processing, continuous, rapid, or low-cost processing.

[0004] CN116262384A (202310143137.1) proposes a method for interface modification of fiber-reinforced metal laminates and its application. This method involves first sandblasting the metal surface, then immersing it in an ethanol solution of rare earth metal salts, drying it, and then placing a resin film between the metal and prepreg before hot pressing to modify the interface. Simultaneously, through laminate structure design and process control, a fiber-reinforced metal laminate is produced. Sandblasting constructs an irregular, clustered, curled structure on the metal surface, utilizing these peaks and valleys with sharp edges to enhance the mechanical interlocking strength between the metal and resin. At the same time, chemical bonding effectively improves the wetting performance of the resin matrix in the prepreg on the metal surface, thereby effectively improving the bonding strength between the metal and resin in the fiber-reinforced metal laminate. However, this method relies on surface sandblasting, which cannot achieve specialized treatment at specific locations. Furthermore, the formation of a hard surface layer can affect the properties of the raw materials, and residual stress exists, leading to reduced interfacial bonding strength after lamination with carbon fiber composites.

[0005] CN119590045A proposes a shear-resistant fiber-metal laminate and its preparation method. This method involves layering ultra-thin stainless steel strips, carbon fiber woven fabric, and unidirectional carbon fiber prepreg. Modified epoxy resin is coated between each two layers during the layering process, and the laminate is cured to obtain the shear-resistant fiber-metal laminate. The resulting shear-resistant fiber-metal laminate improves the shear resistance of the fiber-metal laminate and reduces the possibility of delamination damage, matrix cracking, fiber breakage, and metal plastic deformation. However, this method has a complex process flow and requires precise control of every detail, making it challenging. During the two-stage curing process, temperature or pressure fluctuations may lead to uneven resin flow, residual bubbles, or interlayer slippage. The amount of resin coated between adjacent layers needs precise control, which is difficult to guarantee uniformity in actual production, potentially affecting performance consistency. While adding a stainless steel layer enhances shear strength, it also increases material density, which is detrimental to lightweight requirements. The symmetrical layering design may limit the flexibility of the structure, resulting in poor performance under certain bending loads. Stainless steel surface treatment involves reagents such as alkaline solutions and acidic potassium dichromate, which may generate toxic waste liquids and increase environmental treatment costs.

[0006] The paper "Study on the Influence of Metal Surface Treatment on the Interlaminar Mechanical Properties of FMLs" systematically evaluates the enhancing effects of different surface treatment methods on the interfacial properties of aluminum alloys and resin matrices. It presents various interfacial treatment methods, including mechanical polishing, acid-base corrosion treatment, and phosphoric acid anodizing. Experimental results show that the core function of all treatment methods is to significantly increase the surface roughness of the metal, thereby increasing the contact area and forming mechanical interlocking, which is the physical basis for improved interfacial properties. Phosphoric acid anodizing has a particularly significant effect. However, it is important to note that the thickness and structure of the oxide layer are difficult to precisely control during the anodizing process. As the treatment time increases, the oxide layer thickness increases significantly, leading to a decrease in material properties and limiting further improvements. Furthermore, this method also cannot achieve specialized treatment for specific locations, allowing for personalized settings with different strengths at different locations.

[0007] In summary, while existing surface treatment technologies for aluminum alloy-carbon fiber composite interfaces each have their merits, none have been able to simultaneously improve interfacial bonding strength while also considering cost-effectiveness, environmental friendliness, and the feasibility of large-scale production. Ideally, a technology should significantly improve the interfacial bonding strength without altering the original properties of the metal and composite material, while also possessing high flexibility and applicability to adapt to components of various shapes and sizes. Furthermore, considering the demands of composite materials in high-end applications such as aerospace, the technology should also exhibit good environmental adaptability and long-term stability, ensuring high performance even under extreme conditions.

[0008] Therefore, how to more effectively optimize the interface between aluminum alloy and carbon fiber, and thus provide a method for preparing carbon fiber composite aluminum alloy, so as to prepare carbon fiber composite aluminum alloy with high interfacial bonding strength in a more efficient, lower cost and more environmentally friendly manner, is one of the important technical problems to be solved in this field. Summary of the Invention

[0009] The main objective of this invention is to provide a carbon fiber composite aluminum alloy, its preparation method, and its application, so as to solve the problem that the existing technology cannot prepare carbon fiber composite aluminum alloys with high interfacial bonding strength in a more efficient, lower cost, and more environmentally friendly manner.

[0010] To achieve the above objectives, a first aspect of the present invention provides a method for preparing a carbon fiber composite aluminum alloy, comprising: step S1, providing an aluminum alloy sheet having a first surface and a second surface disposed opposite to each other; performing laser treatment on the first surface and / or the second surface of the aluminum alloy sheet to activate it, thereby obtaining a first activated sheet having an activated surface; step S2, using a coupling agent to modify the activated surface of the first activated sheet, thereby obtaining a second activated sheet having a modified surface; and step S3, bonding a carbon fiber composite material to the modified surface of the second activated sheet, thereby forming a carbon fiber composite layer, and thus obtaining a carbon fiber composite aluminum alloy.

[0011] Furthermore, in step S1, the power of the laser processing is 50W~100W, and the scanning speed is 500mm / s~800mm / s; the waveform of the laser processing is selected from linear waveform, square waveform, or circular waveform.

[0012] Further, step S2 includes: preparing a coupling agent solution with a mass concentration of 1wt% to 5wt%, and adjusting the pH value of the coupling agent solution to 4 to 4.5 using a pH adjuster; immersing the activated surface in the coupling agent solution with a pH value of 4 to 4.5, and performing a modification treatment for 0.1 min to 60 min to obtain a second activated plate with a modified surface; preferably, the pH adjuster is selected from one or more of acetic acid, boric acid, phosphoric acid, and citric acid.

[0013] Furthermore, the coupling agent solution uses ethanol and / or water as solvents, and the coupling agent is a silane coupling agent.

[0014] Furthermore, the water contact angle of the modified surface is 7.3°~76.2°, preferably 7.3°~45.0°; the carbon fiber composite material includes a resin matrix and carbon fibers dispersed in the resin matrix, and the weight percentage of the resin matrix is ​​30±5% based on the total weight of the carbon fiber composite material as 100%.

[0015] Further, in step S3, the composite is achieved by hot pressing, and the hot pressing is carried out at 80℃~145℃ and 0.1MPa~0.7MPa for 2 hours~5 hours; preferably, the composite includes the following steps in sequence: heating from 25±2℃ to 80℃~90℃ at a heating rate of 2±0.2℃ / min and holding at that temperature for 0.5±0.05h; heating from 80℃~90℃ to 115±5℃ at a heating rate of 2±0.2℃ / min and holding at that temperature for 1±0.02h at 0.1MPa~0.7MPa; heating from 115±5℃ to 135℃~145℃ at a heating rate of 2±0.2℃ / min and holding at that temperature for 2±0.05h at 0.1MPa~0.7MPa; and cooling down to 25±2℃ at a cooling rate of 2±0.2℃ / min.

[0016] A second aspect of the present invention provides a carbon fiber composite aluminum alloy, which is prepared by the above-described method for preparing carbon fiber composite aluminum alloy.

[0017] Furthermore, the carbon fiber composite aluminum alloy includes an aluminum alloy sheet and a carbon fiber composite layer disposed on at least one surface of the aluminum alloy sheet, wherein the thickness of the carbon fiber composite layer is 0.1 mm to 3 mm, and the thickness ratio of the carbon fiber composite layer to the aluminum alloy sheet is (0.1 to 3): 1, preferably (0.5 to 1): 1.

[0018] Furthermore, by weight percentage, the aluminum alloy sheet comprises 0.8%–1.2% Mg, 0.4%–0.8% Si, 0.15%–0.4% Cu, 0.04%–0.35% Cr, 0.07%–0.15% Mn, 0.03%–0.25% Zn, 0.025%–0.15% Ti, and 0.3%–0.6% Fe, with the balance being Al and unavoidable impurities; and / or, the carbon fiber diameter in the carbon fiber composite layer is 5–7 mm. m; Preferably, the interfacial shear strength between the aluminum alloy sheet and the carbon fiber composite layer is 40MPa~55MPa.

[0019] A third aspect of the present invention provides an application of the above-mentioned carbon fiber composite aluminum alloy as a structural material in the fields of aerospace, transportation, and high-end equipment and industry.

[0020] By applying the technical solution of this invention, based on the combination of laser surface treatment and coupling agent modification, the surface of aluminum alloy is finely modified with microstructure, the surface chemical activity is enhanced, the physical and chemical bonding with carbon fiber composite material is promoted, and the microstructure of the composite interface is optimized. This achieves the goal of significantly improving the bonding strength of the hybrid interface of aluminum alloy and carbon fiber composite material, thereby enhancing the overall performance of the composite material. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 The scanning electron microscope (SEM) characterization results of the untreated aluminum alloy sheet in Example 1 of this invention;

[0023] Figure 2 The above are the SEM characterization results of the activated surface of the aluminum alloy sheet obtained by laser treatment in Example 1 of this invention;

[0024] Figure 3 The above are the energy scattering spectrometry (EDS) surface scan results of the modified surface of the aluminum alloy sheet obtained by coupling agent modification treatment in Example 1 of this invention;

[0025] Figure 4 This is the EDS surface scan result of the modified surface of the aluminum alloy sheet obtained by coupling agent modification treatment in Comparative Example 2 of the present invention. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0027] As described in the background art, existing technologies have the problem of being unable to prepare carbon fiber composite aluminum alloys with high interfacial bonding strength in a more efficient, lower cost, and more environmentally friendly manner. To solve the above-mentioned technical problem, a first aspect of the present invention provides a method for preparing carbon fiber composite aluminum alloys, comprising: step S1, providing an aluminum alloy sheet having a first surface and a second surface disposed opposite to each other; laser-treating the first surface and / or the second surface of the aluminum alloy sheet to activate it, obtaining a first activated sheet with an activated surface; step S2, using a coupling agent to modify the activated surface of the first activated sheet, obtaining a second activated sheet with a modified surface; step S3, bonding a carbon fiber composite material to the modified surface of the second activated sheet, thereby forming a carbon fiber composite layer, and thus obtaining a carbon fiber composite aluminum alloy.

[0028] This invention significantly improves the interfacial bonding strength between the aluminum alloy sheet and the carbon fiber composite layer through laser treatment and coupling agent modification. In the above preparation method:

[0029] First, laser processing can precisely control the microstructure of the metal surface, forming a microporous structure. This not only increases the surface roughness of the aluminum alloy sheet but also increases the contact area with the subsequent carbon fiber composite material, which is conducive to forming a mechanical interlocking effect, thereby improving the interfacial bonding force. At the same time, compared with traditional methods such as chemical etching, laser processing reduces the use of chemical reagents, lowers the emission of harmful substances, and has a smaller environmental impact. In practical applications, laser processing is also more flexible, allowing adjustments to different areas to suit various complex surface treatments, thus enabling customization and personalization. In this step, the high-energy laser beam acts on the aluminum alloy surface, instantly heating it and melting the surface metal to form tiny pits. As the laser moves, these pits cool and form microstructures of specific shapes, thereby enhancing the chemical activity of the aluminum alloy sheet surface.

[0030] In step S2, the wettability of the activated aluminum alloy surface is further improved through coupling agent treatment, which facilitates the uniform coverage of the subsequent carbon fiber composite material, forming a tight bond without gaps or defects. During the modification process, the coupling agent can form a connection with the aluminum alloy surface, improving its interfacial chemical compatibility with the subsequent carbon fiber composite layer and enhancing the interfacial bonding force. In the subsequent composite process, the organic functional groups in the coupling agent can form covalent bonds with the active groups on the carbon fiber composite material, while the inorganic functional groups form chemical bonds with the oxides or active metal atoms on the laser-treated aluminum alloy surface, acting as a bridge to tightly bind the aluminum alloy and carbon fiber composite material at the molecular level.

[0031] Of course, besides the individual effects of laser treatment and coupling agent modification, the most important factor is the synergistic effect of these two techniques in the preparation process, which significantly enhances the interfacial bonding of the resulting carbon fiber composite aluminum alloy. Specifically, laser treatment first constructs a microstructure on the aluminum alloy surface that strengthens mechanical interlocking, while coupling agent treatment further enhances interfacial bonding by forming chemical bonds. Simultaneously, the microstructure introduced by laser treatment can absorb and disperse interfacial stress, reducing interfacial damage caused by stress concentration; while the chemical bonds formed by coupling agent treatment enhance the flexibility and stability of the interface. Under this combined effect, the resulting composite material exhibits superior performance under dynamic loads.

[0032] In general, this invention is based on a combination of laser surface treatment and coupling agent modification. By performing fine microstructure modification on the aluminum alloy surface, enhancing surface chemical activity, and promoting its physical and chemical bonding with carbon fiber composites, it achieves the goal of significantly improving the interfacial bonding strength of aluminum alloy carbon fiber composite materials.

[0033] In step S1, the laser processing power is preferably 50W~100W, and the scanning speed is 500mm / s~800mm / s, to facilitate the formation of a more uniformly distributed micro / nano-scale porous structure. The laser processing waveform is selected from linear, square, or circular waveforms. To form a superior, more continuous microporous structure that is neither too rough, leading to a decrease in material properties, nor too smooth, affecting the bonding strength, the laser processing power is more preferably 70W~80W, the scanning speed is 600±50mm / s, and the laser processing waveform is a linear waveform. This, combined with the chemical reaction formed by the coupling agent, ultimately achieves a higher interfacial bonding strength.

[0034] In step S2, this step preferably includes: preparing a coupling agent solution with a mass concentration of 1wt% to 5wt%, and adjusting the pH value of the coupling agent solution to 4 to 4.5 using a pH adjuster; immersing the activated surface in the coupling agent solution with a pH value of 4 to 4.5, and performing a modification treatment for 0.1 min to 60 min to obtain a second activated plate with a modified surface. In the above process, by optimizing the concentration of the coupling agent solution, especially its pH value, it is possible to promote the coupling agent to form chemical bonds more effectively on the aluminum alloy surface, thereby significantly improving its chemical compatibility with carbon fiber composites. The preferred reaction time window of 0.1 min to 60 min allows for sufficient modification reaction, promoting chemical bonding while effectively reducing adverse chemical side reactions that may be caused by prolonged reactions. In order to reduce the degradation of interfacial properties caused by excessive accumulation of coupling agent on the aluminum alloy surface, the modification treatment time is preferably 5±2 min, so that the chemical bonding formed can be more coordinated with the physical microstructure formed in the previous step, and ultimately promote the further improvement of the interfacial strength of the resulting composite material.

[0035] In practical applications, the pH adjuster can be selected from one or more of acetic acid, boric acid, phosphoric acid, and citric acid. Furthermore, the coupling agent solution can use ethanol and / or water as a solvent, and the coupling agent is a silane coupling agent, more preferably KH560 and / or KH550.

[0036] When the coupling agent is a silane-based coupling agent, especially one selected from KH560 and / or KH550, its molecule typically consists of two parts: one is a hydrolyzable silane group, such as methoxy (-OMe) or ethoxy (-OEt); the other is a functional organic group, such as amino (-NH2), epoxy (-CH2-CH(OH)-), or vinyl (-CH=CH2). This enables efficient and stable interfacial bonding between aluminum alloys and carbon fiber composites (other silane coupling agents, such as KH570, are slightly less effective due to their functional groups). Specifically, the oxide layer formed after laser treatment of aluminum alloy sheets will form hydrated alumina during the modification stage; while the silane group undergoes hydrolysis to generate a silanol intermediate with active hydroxyl groups (-OH). The two then undergo dehydration condensation to form Si-O-Al bonds (covalent bonds), thereby tightly fixing the silane coupling agent molecules to the aluminum alloy surface. In the subsequent composite stage, the organic functional groups on the silane coupling agent can chemically react with the active functional groups on the surface of the carbon fiber composite (mainly the resin matrix). Ultimately, this achieves a more efficient and stable interfacial bond between the aluminum alloy and the carbon fiber composite.

[0037] Furthermore, the coupling agent solution preferably uses a mixture of ethanol and water as the solvent, with a weight ratio of ethanol to water of (6~8):1. In this mixture, ethanol, as an organic solvent, can better dissolve the coupling agent, while the presence of water is key to initiating the hydrolysis reaction of the coupling agent. Optimizing this weight ratio allows for a better balance between solubility and the reactivity of the coupling agent, promoting the formation of a more uniform and stable chemical bond layer on the aluminum alloy surface. This, in turn, allows for better integration with the physical microstructure formed by laser processing, further enhancing the interfacial bonding strength of the resulting composite material.

[0038] In several typical embodiments, the water contact angle of the modified surface is 7.3°~76.2° (more preferably 7.3°~45.0°). That is, the modified surface obtained after laser treatment and coupling agent modification has higher wettability. Good wettability means a tighter and more uniform interfacial bond between the modified surface and the carbon fiber composite, ultimately significantly improving the overall structural stability and reliability of the resulting composite material. Based on this, energy dispersive spectroscopy was used to analyze the elements on the modified surface. Preferably, the content of C on the modified surface is 20wt%~25wt%, the content of O is 6wt%~10wt%, and the content of Si is 2wt%~4wt%. In this preferred embodiment, the carbon element comes from the coupling agent treatment, and its higher content indicates that the coupling agent has successfully covered and modified the aluminum alloy surface; the higher oxygen element content may reflect the degree of oxide layer on the aluminum alloy surface at this time, which is conducive to further improving surface activity and promoting a tighter bonding with the carbon fiber composite layer in the future; while the appropriate content of silicon element comes from the silane group in the coupling agent, which can participate in the formation of chemical bonds, thereby significantly enhancing the interfacial bonding force in the final carbon fiber composite aluminum alloy.

[0039] In step S3, the composite is preferably achieved through hot pressing, and the hot pressing is carried out at 80℃~145℃ and 0.1MPa~0.7MPa for 2~5 hours. By optimizing the parameters in the above composite process based on the surface state of the aluminum alloy at this time, not only can the molding of the composite material be accelerated, but the microstructure at the interface of the resulting composite material can also be further optimized, promoting a tighter bond between the aluminum alloy and the carbon fiber composite material, forming a bubble-free, denser, and stronger composite interface. In several more typical embodiments, in order to form a more uniform and denser carbon fiber composite layer, and to further enhance the bonding strength between the formed composite layer and the aluminum alloy, the composite process preferably includes the following steps: heating from 25±2℃ to 80℃~90℃ at a heating rate of 2±0.2℃ / min, and holding at that temperature for 0.5±0.05h; heating from 80℃~90℃ to 115±5℃ at a heating rate of 2±0.2℃ / min, and holding at that temperature for 1±0.02h at 0.1MPa~0.7MPa; heating from 115±5℃ to 135℃~145℃ at a heating rate of 2±0.2℃ / min, and holding at that temperature for 2±0.05h at 0.1MPa~0.7MPa; and cooling down to 25±2℃ at a cooling rate of 2±0.2℃ / min.

[0040] Furthermore, the preferred carbon fiber composite material includes a resin matrix and carbon fibers dispersed within the resin matrix. With the total weight of the carbon fiber composite material being 100%, the resin matrix accounts for 30±5% of the total weight. This facilitates the bonding of the matrix resin, acting as a binder within the carbon fiber composite material, more tightly to the modified surface, thereby significantly improving the interfacial bonding strength. Simultaneously, it further enhances the plasticity of the formed carbon fiber composite layer, resulting in a carbon fiber composite aluminum alloy with higher fatigue resistance and reliability. In practical applications, the resin matrix can be epoxy resin.

[0041] A second aspect of this invention provides a carbon fiber composite aluminum alloy, which is prepared by the aforementioned method for preparing carbon fiber composite aluminum alloys. Based on the preparation method including laser treatment and coupling agent modification, the obtained carbon fiber composite aluminum alloy product possesses higher interfacial shear strength, lower risk of interfacial delamination, and superior fatigue resistance. It should be noted that due to the complex structural changes during the preparation process, and due to the special characteristics of composite materials and limitations of existing testing and characterization methods, it is difficult to comprehensively and quantitatively characterize the complex microstructure of the aforementioned carbon fiber composite aluminum alloy. However, performance test results have already shown that in the aforementioned carbon fiber composite aluminum alloy obtained by this invention, the aluminum alloy sheet and the carbon fiber composite layer are more tightly bonded, thus better balancing various performance characteristics.

[0042] Furthermore, the carbon fiber composite aluminum alloy includes an aluminum alloy sheet and a carbon fiber composite layer disposed on at least one surface of the aluminum alloy sheet. The thickness of the carbon fiber composite layer is 0.1 mm to 3 mm, and the thickness ratio of the carbon fiber composite layer to the aluminum alloy sheet is (0.1~3):1, preferably (0.5~1):1. Within the above-mentioned preferred thickness and thickness relationship range, the resulting carbon fiber composite aluminum alloy can better bear the load, reduce delamination damage, and more significantly exert the advantages of lightweight and high strength.

[0043] For aluminum alloy sheets, the preferred composition by weight percentage includes 0.8%~1.2% Mg, 0.4%~0.8% Si, 0.15%~0.4% Cu, 0.04%~0.35% Cr, 0.07%~0.15% Mn, 0.03%~0.25% Zn, 0.025%~0.15% Ti, and 0.3%~0.6% Fe, with the balance being Al and unavoidable impurities. This composition better provides structural support and strength, further optimizing the overall performance of the resulting carbon fiber composite aluminum alloy. The preferred carbon fiber diameter in the carbon fiber composite layer is 5μm~7μm. Continuous carbon fibers of m can improve the uniformity of carbon fiber distribution in the carbon fiber composite layer, and at the same time further enhance the tightness of the interfacial bonding, forming a composite interface with higher shear strength.

[0044] In several preferred embodiments, the interfacial shear strength between the aluminum alloy sheet and the carbon fiber composite layer is 40 MPa to 55 MPa. That is to say, the carbon fiber composite aluminum alloy obtained by this invention possesses an interfacial shear strength far exceeding that of traditional composite materials, signifying a particularly significant improvement in its stability under shear force.

[0045] A third aspect of this invention provides an application of the aforementioned carbon fiber composite aluminum alloy as a structural material in the aerospace, transportation, and high-end equipment and industrial fields. Based on the synergistic optimization of laser processing and coupling agent modification, the composite material obtained by this invention possesses superior interfacial bonding properties, while also exhibiting significant enhancements in physical structure and chemical properties, thus better meeting application standards in various fields.

[0046] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0047] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0048] Example 1

[0049] A method for preparing carbon fiber composite aluminum alloy:

[0050] (1) An aluminum alloy with the following composition was prepared: 0.656% Si, 0.507% Fe, 0.174% Cu, 0.0706% Mn, 1.027% Mg, 0.131% Cr, 0.00547% Ni, 0.034% Zn, and 0.0267% Ti, with the balance being Al and unavoidable impurities. The above raw materials were melted, cast, and rolled to obtain an aluminum alloy sheet with a thickness of 1 mm. The SEM characterization results are shown in [Figure number missing]. Figure 1 Laser modification was performed on one side of the obtained aluminum alloy sheet using a linear waveform. The laser power was 70W, and the scanning speed was 600mm / s to activate the surface. SEM characterization of the surface was then performed, and the results are shown below. Figure 2 .

[0051] Depend on Figure 1 It is evident that the surface of the untreated aluminum alloy sheet samples exhibits typical characteristics of rolled sheet materials. The overall morphology is relatively smooth, but there are obvious parallel stripes or groove-like structures extending along a dominant direction. These rolling textures are macroscopic mechanical marks left by the interaction between the rolls and the aluminum sheet surface during the final rolling process. After laser treatment, however, the surface becomes... Figure 2 It can be seen that there are obvious micropores on the surface of the aluminum material, and even the inside of a single micropore can be seen.

[0052] (2) Prepare a silane coupling agent solution with a mass concentration of 3.5 wt% by mixing silane coupling agent (KH560), anhydrous ethanol, and deionized water in a mass ratio of 3.5:85:11.5 (i.e., the weight ratio of ethanol to water in the mixed solvent is 7.4:1). During the preparation process, anhydrous ethanol and deionized water are added first, followed by the silane coupling agent. Adjust the pH of the silane coupling agent solution to 4 to 4.5 using acetic acid solution. Then, immerse the activated surface formed in step (1) in the silane coupling agent solution and carry out a modification reaction for 5 minutes to further transform the activated surface into a modified surface.

[0053] The modified surface was subjected to EDS surface scanning, and the characterization results are shown in the figure. Figure 3 .Depend on Figure 3 It can be seen that the content of Al on this surface is 64.2 wt%, C is 24.1 wt%, O is 7.9 wt%, and Si is 2.8 wt%. Meanwhile, from... Figure 3It is known that laser-assisted silanization treatment further disperses the enriched regions of C, O, and Si elements on the surface of aluminum alloy sheets, and increases the content of these three elements. The elements introduced by silanization treatment may alter the physical and chemical properties of the aluminum surface. From a chemical perspective, the enrichment of C, O, and Si elements may form new chemical bonds and functional groups. This change in chemical composition has a significant impact on the surface properties of the aluminum alloy sheet. After treatment, the contact angle of the aluminum alloy sheet with water is also significantly improved.

[0054] (3) The carbon fiber composite prepreg (a mixture of epoxy resin and carbon fiber, wherein the mass percentage of epoxy resin is 30% and the carbon fiber is continuous carbon fiber with a diameter of 6) is used. The resin (70% by mass) is bonded to the modified surface formed in step (2), and heated from room temperature to 80°C at a rate of 2°C / min, and held for 0.5 h to ensure that the resin fully wets the metal and removes air bubbles. Next, the pressure is increased to 0.6 MPa (the pressure is kept constant in the subsequent process), and the temperature is increased to 115°C at a rate of 2°C / min and held for 1 h. Then, the temperature is increased to 145°C at a rate of 2°C / min and held for 2 h. Finally, the temperature is decreased to room temperature at a rate of 2°C / min to obtain a carbon fiber composite aluminum alloy with a carbon fiber composite layer thickness of 0.5 mm.

[0055] Example 2

[0056] A method for preparing carbon fiber composite aluminum alloy:

[0057] The only difference between this embodiment and embodiment 1 is that in step (1), the waveform of the laser processing is changed to a square waveform, and the power of the laser processing is changed to 50W and the scanning speed is changed to 500mm / s.

[0058] Example 3

[0059] A method for preparing carbon fiber composite aluminum alloy:

[0060] The only difference between this embodiment and embodiment 1 is that in step (1), the waveform of the laser processing is changed to a circular waveform, and the power of the laser processing is changed to 100W, and the scanning speed is changed to 800mm / s.

[0061] Example 4

[0062] A method for preparing carbon fiber composite aluminum alloy:

[0063] The only difference between this embodiment and embodiment 1 is that in step (2), a mixture of ethanol and water in a weight ratio of 3:1 is used as the solvent, while the mass concentration of the silane coupling agent remains unchanged.

[0064] Example 5

[0065] A method for preparing carbon fiber composite aluminum alloy:

[0066] The only difference between this embodiment and Example 1 is that in step (2), acetic acid was not used to adjust the pH value of the silane coupling agent, but a silane coupling agent solution with a basically neutral pH was directly used for modification.

[0067] Example 6

[0068] A method for preparing carbon fiber composite aluminum alloy:

[0069] The only difference between this embodiment and embodiment 1 is that in step (2), the time for modifying the coupling agent solution is changed from 5 min to 1 min.

[0070] Example 7

[0071] A method for preparing carbon fiber composite aluminum alloy:

[0072] The only difference between this embodiment and embodiment 1 is that in step (2), the time for modifying the coupling agent solution is changed from 5 min to 60 min.

[0073] Example 8

[0074] A method for preparing carbon fiber composite aluminum alloy:

[0075] The only difference between this embodiment and embodiment 1 is that in step (2), the coupling agent is changed from KH560 to KH570.

[0076] Example 9

[0077] A method for preparing carbon fiber composite aluminum alloy:

[0078] The only difference between this embodiment and embodiment 1 is that in step (3), the conditions of vacuum hot pressing are changed to: heating from room temperature to 115°C at a heating rate of 2°C / min, pressurizing to 0.6MPa at this temperature and holding for 1h, then heating to 145°C at a heating rate of 2°C / min and holding for 2h, and finally cooling to room temperature at a rate of 2°C / min to obtain carbon fiber composite aluminum alloy.

[0079] Example 10

[0080] A method for preparing carbon fiber composite aluminum alloy:

[0081] The difference between this embodiment and Embodiment 1 is only that in step (3), the conditions of the vacuum hot pressing process are changed to: heating from room temperature to 80°C at a heating rate of 2°C / min, holding at that temperature for 0.5h to ensure that the resin fully impregnates the metal and removes air bubbles. Then, pressurizing to 0.6MPa (keeping the pressure constant in subsequent processes), heating to 145°C at a heating rate of 2°C / min, holding at that temperature for 3h, and finally cooling to room temperature at a rate of 2°C / min to obtain carbon fiber composite aluminum alloy.

[0082] Comparative Example 1

[0083] A method for preparing carbon fiber composite aluminum alloy:

[0084] The only difference between this comparative example and Example 1 is that no coupling agent modification treatment was performed. Instead, the aluminum alloy sheet obtained in step (1) and the carbon fiber composite layer were directly combined to form a carbon fiber composite aluminum alloy. The specific composite operation was carried out in step (3) of Example 1.

[0085] Comparative Example 2

[0086] A method for preparing carbon fiber composite aluminum alloy:

[0087] The only difference between this comparative example and Example 1 is that: no laser treatment was performed, but the aluminum alloy sheet without any treatment was directly modified with a coupling agent according to step (2), and the aluminum alloy sheet modified with only the coupling agent was combined with the carbon fiber composite layer according to step (3) to form a carbon fiber composite aluminum alloy.

[0088] Meanwhile, prior to composite preparation, the coupling agent-modified surfaces obtained in this comparative example were subjected to EDS surface scanning, and the characterization results are shown in [Figure number missing]. Figure 4 .

[0089] Comparative Example 3

[0090] A method for preparing carbon fiber composite aluminum alloy:

[0091] The only difference between this comparative example and Example 1 is that no laser treatment and coupling agent modification were performed. Instead, the aluminum alloy sheet without any treatment was directly composited with the carbon fiber composite layer in step (3) to form a carbon fiber composite aluminum alloy.

[0092] Comparative Example 4

[0093] A method for preparing carbon fiber composite aluminum alloy:

[0094] The only difference between this comparative example and Example 1 is that, in step (2), an equal weight of sodium dodecylbenzenesulfonate surfactant is used to replace the coupling agent KH560.

[0095] Test methods

[0096] Contact angle of aluminum alloy sheet surface before composite with carbon fiber layer: measured using a contact angle tester.

[0097] Interfacial shear strength at the interface between the carbon fiber layer and the aluminum alloy sheet: obtained by testing according to GB / T 1450.1-2005.

[0098] For each embodiment and comparative example, the contact angle of the aluminum alloy sheet surface before being combined with the carbon fiber layer, and the interfacial shear strength of the interface between the carbon fiber layer and the aluminum alloy sheet in the final carbon fiber composite aluminum alloy sample are all shown in Table 1.

[0099] Table 1

[0100]

[0101] As can be seen from the above description, compared with the various comparative examples, the above embodiments of the present invention, based on the combination of laser surface treatment and coupling agent modification, have achieved the preparation of high-performance carbon fiber composite aluminum alloy materials. The resulting composite material not only has high interfacial bonding strength, but also significantly improves the flexibility of its preparation process, environmental friendliness, and product benefits.

[0102] Specifically, in each embodiment:

[0103] Comparing Examples 2 and 3 with Example 1, it can be seen that by optimizing the specific conditions of laser treatment, a superior microporous structure with a more continuous arrangement can be formed. This structure is neither too rough, which would lead to a decrease in material performance, nor too smooth, which would affect the bonding force. Ultimately, it combines with the chemical action formed by the coupling agent to achieve a higher interfacial bonding strength.

[0104] Comparing Example 4 with Example 1, it can be seen that by optimizing the solvent system used to prepare the coupling agent solution during the modification process, the solubility and reactivity of the coupling agent can be better balanced, which promotes the coupling agent to form a more uniform and stable chemical bond connection layer on the aluminum alloy surface, thereby better cooperating with the physical microstructure formed by laser treatment and further improving the interfacial bonding strength in the obtained composite material.

[0105] Comparing Example 5 with Example 1, it can be seen that by adjusting the pH of the coupling agent solution used in the modification process, the coupling agent can be made to form chemical bonds more effectively on the aluminum alloy surface, thereby significantly improving its chemical compatibility with carbon fiber composites.

[0106] Comparing Examples 6 and 7 with Example 1, it can be seen that by optimizing the timing of the coupling agent modification, the resulting chemical bonding effect can be more coordinated with the physical microstructure formed in the previous step, ultimately leading to a further improvement in the interfacial strength of the resulting composite material.

[0107] Comparing Example 8 with Example 1, it can be seen that by optimizing the type of coupling agent used for modification, a more efficient and stable interfacial connection between aluminum alloy and carbon fiber composite can be achieved.

[0108] Comparing Examples 9 and 10 with Example 1, it can be seen that by optimizing the specific conditions of composite hot pressing, the microstructure at the interface of the obtained composite material can be further optimized, enabling the aluminum alloy to bond more tightly with the carbon fiber composite material, forming a composite interface that is bubble-free, denser, and has a stronger bond.

[0109] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those described herein.

[0110] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for producing a carbon fiber-reinforced aluminum alloy, characterized by, The method comprises the following steps: S1, providing an aluminum alloy plate having a first surface and a second surface arranged oppositely; carrying out laser treatment on the first surface and / or the second surface to activate the same, thereby obtaining a first activated plate having an activated surface; S2, modifying the activated surface of the first activated plate by using a coupling agent, thereby obtaining a second activated plate having a modified surface; S3, bonding a carbon fiber composite material to the modified surface of the second activated plate, and forming a carbon fiber composite layer by compounding, thereby obtaining the carbon fiber composite aluminum alloy.

2. The method of claim 1, wherein the carbon fiber reinforced aluminum alloy is prepared by the steps of: preparing an aluminum alloy; preparing a carbon fiber; and mixing the aluminum alloy and the carbon fiber. In the step S1, the power of the laser treatment is 50 W to 100 W, and the scanning speed is 500 mm / s to 800 mm / s; the waveform of the laser treatment is selected from a linear waveform, a square waveform or a circular waveform.

3. The method for producing a carbon fiber-reinforced aluminum alloy according to claim 1 or 2, characterized by, The step S2 comprises: the coupling agent is prepared into a coupling agent solution with a mass concentration of 1 wt% to 5 wt%, and a pH adjuster is used to adjust the pH value of the coupling agent solution to 4 to 4.5; the activated surface is soaked in the coupling agent solution with a pH value of 4 to 4.5, and the modification treatment is carried out for 0.1 min to 60 min, thereby obtaining the second activated plate having the modified surface; Preferably, the pH adjuster is selected from one or more of acetic acid, boric acid, phosphoric acid and citric acid.

4. The method of producing a carbon fiber-reinforced aluminum alloy according to claim 3, characterized by, The coupling agent solution uses ethanol and / or water as a solvent, and the coupling agent is a silane coupling agent.

5. The method for preparing the carbon fiber composite aluminum alloy according to any one of claims 1 to 4, wherein the water contact angle of the modified surface is 7.3° to 76.2°, preferably 7.3° to 45.0°; the carbon fiber composite material comprises a resin matrix and carbon fibers dispersed in the resin matrix, and the weight percentage of the resin matrix in the total weight of the carbon fiber composite material is 30±5%.

6. The method of producing a carbon fiber-reinforced aluminum alloy according to any one of claims 1 to 5, characterized by, In the step S3, the compounding is realized by hot pressing, and the hot pressing is carried out at 80°C to 145°C and 0.1 MPa to 0.7 MPa, and the time of the hot pressing is 2 hours to 5 hours; Preferably, the compounding comprises the following steps in sequence: heating from 25±2°C to 80°C to 90°C at a heating rate of 2±0.2°C / min, and maintaining the temperature for 0.5±0.05 h; heating from 80°C to 90°C to 115±5°C at a heating rate of 2±0.2°C / min, and maintaining the temperature at 0.1 MPa to 0.7 MPa for 1±0.02 h; heating from 115±5°C to 135°C to 145°C at a heating rate of 2±0.2°C / min, and maintaining the temperature at 0.1 MPa to 0.7 MPa for 2±0.05 h; and cooling to 25±2°C at a cooling rate of 2±0.2°C / min.

7. A carbon fiber reinforced aluminum alloy characterized by, The carbon fiber composite aluminum alloy is prepared by the method for preparing the carbon fiber composite aluminum alloy according to any one of claims 1 to 6.

8. The carbon fiber composite aluminum alloy of claim 7, wherein, The carbon fiber composite aluminum alloy comprises the aluminum alloy plate and the carbon fiber composite layer arranged on at least one side surface of the aluminum alloy plate, and the thickness of the carbon fiber composite layer is 0.1 mm to 3 mm, and the ratio of the thickness of the carbon fiber composite layer to the thickness of the aluminum alloy plate is (0.1-3):1, preferably (0.5-1):

1.

9. The carbon fiber composite aluminum alloy of claim 7 or 8, wherein, The composition of the aluminum alloy plate includes, in percentage by weight, 0.8%~1.2% of Mg, 0.4%~0.8% of Si, 0.15%~0.4% of Cu, 0.04%~0.35% of Cr, 0.07%~0.15% of Mn, 0.03%~0.25% of Zn, 0.025%~0.15% of Ti, and 0.3%~0.6% of Fe, with the balance being Al and inevitable impurities; and / or, the carbon fiber in the carbon fiber composite layer has a diameter of 5 m~7 m; Preferably, the interfacial shear strength of the interface between the aluminum alloy plate and the carbon fiber composite layer is 40 MPa to 55 MPa.

10. Application of the carbon fiber composite aluminum alloy in any one of claims 7 to 9 as a structural material in the fields of aerospace, transportation, and high-end equipment and industry.

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