Method for improving bonding performance of thermoplastic carbon fiber composite material-aluminum alloy

Abstract

The invention relates to a method for improving the bonding performance of a thermoplastic carbon fiber composite material and an aluminum alloy. Aiming at different characteristics of a thermoplastic composite material and an aluminum alloy, different process combinations such as mechanical polishing, organic solvent cleaning, vacuum plasma treatment and flame treatment are adopted to carry out cooperative treatment on the surfaces of the thermoplastic composite material and the aluminum alloy base material, so that the surface roughness of the base material is effectively changed, surface dirt is removed, and a polar functional group is introduced; compared with a traditional single mechanical polishing or plasma treatment method, the method has the advantages that the bonding strength and plasticity of the thermoplastic composite material and the aluminum alloy can be greatly improved, and the method is applied to the field of connection of the thermoplastic composite material and the aluminum alloy heterogeneous material.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of dissimilar material joining, in particular to a method for improving the bonding performance of thermoplastic carbon fiber composite material-aluminum alloy. BACKGROUND

[0002] Under the driving of lightweight and green demand, thermoplastic carbon fiber composite material has been widely concerned in the field of automobile manufacturing due to its high specific strength, high specific stiffness and recyclable characteristics. In the process of using thermoplastic carbon fiber composite parts, it is inevitable to connect with metal parts. As a common connection method, bonding has the advantages of good fatigue resistance and good corrosion resistance. However, due to the difference in the physical and chemical properties of the surface of the bonding substrate, there will be great performance difference. The surface energy of thermoplastic composite material and aluminum alloy is low, and the adhesive is difficult to infiltrate, so the direct bonding strength and plasticity are difficult to guarantee, which limits the application of thermoplastic carbon fiber composite parts in automobile engineering. SUMMARY

[0003] The present application provides a method for improving the bonding performance of thermoplastic carbon fiber composite material and aluminum alloy, which is based on the surface treatment method combining mechanical polishing, vacuum plasma treatment technology and flame treatment technology, to improve the bonding strength and plasticity of thermoplastic carbon fiber composite material and aluminum alloy, thereby improving the connection performance.

[0004] To achieve the above-mentioned purpose, the present application provides a method for improving the bonding performance of thermoplastic carbon fiber composite material-aluminum alloy, which comprises the following steps:

[0005] Step one, the surface treatment process of the substrate is as shown in Figure 1 The thermoplastic carbon fiber composite material and aluminum alloy are selected as the bonding substrate. First, the bonding surface of the substrate is polished with sandpaper, then the surface is cleaned with organic solvent, and finally the substrate is dried in an oven;

[0006] Step two, the process parameter combination suitable for the surface activation treatment of the composite material is obtained by optimizing the process parameter combination of the vacuum plasma treatment, such as power, distance and time, etc., using the thermoplastic composite material substrate to be bonded. The composite material substrate is placed in the vacuum plasma machine for surface treatment with the optimized process parameter combination;

[0007] Step three, the process parameter combination suitable for the surface activation treatment of the aluminum alloy substrate is obtained by optimizing the process parameter combination of the flame treatment, such as flame temperature, distance and time, etc., using the aluminum alloy substrate to be bonded. The aluminum alloy is surface treated with the optimized process parameter combination;

[0008] Step four, the composite material substrate, aluminum alloy substrate and adhesive are preheated in an oven;

[0009] Step five, after the adhesive is evenly mixed after preheating, it is applied to the bonding area of the composite material, then glass beads are placed at the bonding position, and finally the aluminum alloy is gently placed on the composite material for bonding, and a clamping device is used to pressurize the bonding position;

[0010] Step six, the test piece is placed in an oven for heating, and after initial curing, the test piece is taken out and the glue tumor at the connection of the test piece is cleaned, and after post-curing, the mechanical property test is performed.

[0011] Through the processing setting method in the above steps, a high-performance thermoplastic carbon fiber composite material and aluminum alloy bonded joint can be prepared, which is suitable for application fields requiring high strength and good plastic connection of heterogeneous materials.

[0012] Preferably, the thermoplastic carbon fiber composite material is a polyamide-based carbon fiber composite material, the aluminum alloy is 6082-T6 aluminum alloy, and the substrate size is 100×25×3.0 mm 3 , as shown in Figure 2 . The composite material is polished with 400-800# sandpaper, and the aluminum alloy is polished with 180-400# sandpaper.

[0013] Preferably, in step one, isopropyl alcohol is used as a cleaning agent to remove surface dirt.

[0014] Preferably, in step one, after the dirt is cleaned, the test piece is placed in an oven at a temperature of 20-35 ºC for 10-30 min for drying, and after natural cooling, the test piece is placed in a sealed environment for standby.

[0015] Preferably, in step two, for the vacuum plasma treatment method of the composite material, the gas is air, the vacuum degree in the treatment chamber is controlled at -10 to -40 Pa, the power is 100-160 W, the gas flow rate is 40-80 mL / min, and the treatment time is 250-400 s.

[0016] Preferably, in step three, the aluminum alloy flame treatment temperature is 1100-1300°C, the flame nozzle distance from the test piece is 100-130 mm, and the treatment time is 30-50 s.

[0017] Preferably, in step four, the adhesive is a two-component polyurethane adhesive, and the preheating temperature of the adhesive and the substrate to be bonded is 25-40°C.

[0018] Preferably, in step five, 60-mesh glass beads are placed in the bonding area at 10-30, the pressurization mode is "F" clamping pressurization, and the bonding thickness is 0.5-1 mm.

[0019] Preferably, in the step six, the initial curing time is 20-26 h, the curing temperature is 20-40 DEG C, the post-curing time is 7 days, and the curing temperature is 20-30 DEG C.

[0020] By the synergistic treatment of mechanical polishing, organic solvent cleaning, vacuum plasma treatment, flame treatment and the like, the quality and mechanical properties of the thermoplastic carbon fiber composite material and the aluminum alloy adhesive joint are improved, and compared with the prior art, the present application has the following beneficial technical effects:

[0021] 1. By mechanical polishing treatment, the roughness of the adhesive surface can be increased to form a micro-mechanical embedding effect.

[0022] 2. By isopropanol cleaning, oil stains, release agents or contaminants can be removed to improve the surface tension of the substrate.

[0023] 3. By controlling the power, distance and treatment time of the vacuum plasma treatment process, polar functional groups can be introduced to improve the surface energy of the polyamide carbon fiber composite material, and the wettability and interfacial strength of the thermoplastic carbon fiber composite material and the adhesive.

[0024] 4. By controlling the temperature, distance and treatment time of the flame treatment process, the roughness of the adhesive surface can be further improved to enhance the embedding effect, and polar functional groups can be introduced to improve the surface energy of the aluminum alloy, and the wettability and interfacial strength of the aluminum alloy and the adhesive.

[0025] 5. Compared with the traditional single surface treatment process, after the synergistic treatment of mechanical polishing, organic solvent cleaning, vacuum plasma treatment, flame treatment and the like, the adhesive strength and plasticity of the polyamide-based carbon fiber composite material and the aluminum alloy are obviously improved.

[0026] 6. Compared with the traditional adhesive bonding process, as shown in Figure 3 After the synergistic treatment of mechanical polishing, organic solvent cleaning, vacuum plasma treatment, flame treatment and the like, the adhesive failure mode is changed from the mixed failure mode of adhesive interface failure and adhesive cohesive failure to the adhesive cohesive failure mode.

[0027] By the adhesive bonding process of the present application, the adhesive strength between the thermoplastic carbon fiber composite material and the aluminum alloy can be significantly improved and has good plasticity, which is suitable for the application scenarios of high-strength light-weight components such as automobiles, aerospace, rail transportation and the like. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 - composite material substrate and aluminum alloy substrate surface treatment flowchart of the present application;

[0029] Figure 2- The schematic diagram of the thermoplastic carbon fiber composite material plate and the metal plate of the present application is glued;

[0030] Figure 3 - (1) The failure mode of the tensile specimen made by the surface treatment process of organic solvent cleaning; (2) The failure mode of the tensile specimen made by the surface treatment process of mechanical polishing; (3) The failure mode of the tensile specimen made by the collaborative treatment of the processes of mechanical polishing, organic solvent cleaning, vacuum plasma treatment, and flame treatment. DETAILED DESCRIPTION

[0031] The embodiments of the present application will be clearly and completely described below by examples. Obviously, the described examples are only used to illustrate the present application, but cannot be used to limit the scope of the present application.

[0032] Example 1:

[0033] The purpose of the present application is to provide a process technology for improving the single lap joint strength of thermoplastic carbon fiber composite material and aluminum alloy by collaborative treatment of the processes of mechanical polishing, organic solvent cleaning, vacuum plasma treatment, and flame treatment on the surface of the glued base material, to solve the problems in the prior art. The specific steps are as follows:

[0034] Step one, the surface treatment method is as shown in Figure 1 The polyamide-based carbon fiber composite material and 6082-T6 aluminum alloy are selected as the glued base material. First, the 400# sandpaper is used to polish the glued surface of the aluminum alloy base material, the 600# sandpaper is used to polish the glued surface of the polyamide-based carbon fiber composite material base material, then the isopropyl alcohol is used to clean the polished surface, and finally the oven is used for drying treatment at 40 ℃ for 30 min;

[0035] Step two, the composite material glued surface is treated by using the vacuum plasma technology, the gas is air, the vacuum degree in the treatment chamber is controlled at-20 Pa, the power is 150 W, the gas flow rate is 60 mL / min, and the treatment time is 300 s;

[0036] Step three, the aluminum alloy surface is treated by using the flame treatment process, the flame temperature is 1200 ℃, the distance between the flame nozzle and the specimen is 110 mm, and the treatment time is 30 s;

[0037] Step four, the YQDB7823 two-component polyurethane adhesive is selected, and the glued base material and the adhesive are preheated to 25 ℃;

[0038] Step five, 5 glass beads of 35 mesh are uniformly placed in the glued area, the "F" clamp is used to clamp the glued area for pressure curing, and the glued thickness is 0.5 mm;

[0039] Step six, the test piece is placed in the oven for heating and curing, the initial curing temperature is 35 DEG C, the initial curing time is 24 h, after the initial curing is completed, post-curing is carried out, the post-curing temperature is 25 DEG C, and the curing time is 7 days.

[0040] Compared with the use of traditional single mechanical polishing or organic solvent cleaning process for bonding, the use of mechanical polishing, organic solvent cleaning, vacuum plasma treatment and other processes for synergistic treatment of the surface of the composite material, the use of mechanical polishing, organic solvent cleaning, flame treatment and other processes for synergistic treatment of the surface of the aluminum alloy, the bonding strength can reach 16 MPa, the performance is improved by more than 33%, and the elongation rate reaches 12%, the performance is improved by more than 50%. The specific test results are shown in the following table.

[0041]

[0042] Example 2:

[0043] The purpose of the present application is to provide a process technology for synergistically treating the surface of the bonding material by mechanical polishing, organic solvent cleaning, vacuum plasma treatment, flame treatment and other processes, and improving the bonding strength of thermoplastic carbon fiber composite material and aluminum alloy single lap joint, to solve the problems in the prior art, and the specific steps are as follows:

[0044] Step one, selecting polyamide-based carbon fiber composite material and 6082-T6 aluminum alloy as the bonding base material; first, using 400# sandpaper to polish the bonding surface of the aluminum alloy base material, using 600# sandpaper to polish the bonding surface of the polyamide-based carbon fiber composite material base material, then using isopropyl alcohol to clean the polished surface, and finally placing in an oven for drying treatment at 40 DEG C for 30 min;

[0045] Step two, using vacuum plasma technology to treat the bonding surface of the composite material, the gas is air, the vacuum degree in the treatment chamber is controlled at-20 Pa, the power is 150 W, the gas flow rate is 60 mL / min, and the treatment time is 300 s;

[0046] Step three, using flame treatment process to treat the surface of the aluminum alloy, the flame temperature is 1200 DEG C, the distance between the flame nozzle and the test piece is 110 mm, and the treatment time is 30 s;

[0047] Step four, selecting YQDB7823 two-component polyurethane adhesive, and preheating the bonding base material and the adhesive to 25 DEG C;

[0048] Step five, placing 5 glass beads of 18 mesh in the bonding area, using "F" clamp to clamp the bonding area for pressure curing, and the bonding thickness is 1 mm;

[0049] Step 6: Place the specimen in an oven for heating and curing. The initial curing temperature is 35 ℃ and the initial curing time is 24 h. After the initial curing is completed, perform post-curing at 25 ℃ for 7 days.

[0050] Compared to traditional single mechanical grinding or organic solvent cleaning processes followed by bonding, using a combination of mechanical grinding, organic solvent cleaning, and vacuum plasma treatment to treat the composite material surface, and using a combination of mechanical grinding, organic solvent cleaning, and flame treatment to treat the aluminum alloy surface, the bonding strength can reach 15 MPa, an improvement of over 31%, and the elongation reaches 16%, an improvement of over 60%. Specific test results are shown in the table below.

[0051]

[0052] This invention significantly improves the bonding performance between thermoplastic carbon fiber composites and aluminum alloys by using a combination of mechanical grinding, organic solvent cleaning, vacuum plasma treatment, and flame treatment to treat the substrate. This overcomes the shortcomings of traditional treatment methods and can effectively promote the application of thermoplastic composites in the automotive manufacturing field, thereby improving the safety and reliability of the structure.

[0053] The embodiments of the present invention are provided for illustrative and descriptive purposes. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, and substitutions to the above embodiments within the scope of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for improving the bonding performance of thermoplastic carbon fiber composites with aluminum alloys, characterized in that, Based on the different properties of thermoplastic carbon fiber composites and aluminum alloys, different combinations of process methods, including mechanical grinding, organic solvent cleaning, vacuum plasma treatment, and flame treatment, were used to process the thermoplastic carbon fiber composite substrate and the aluminum alloy substrate in sequence, including the following steps: Step 1: Select thermoplastic carbon fiber composite material and aluminum alloy as the bonding substrate. First, sand the bonding surface of the substrate with sandpaper, then clean the surface with organic solvent, and finally put it in an oven to dry. Step 2: Place the thermoplastic carbon fiber composite substrate into a vacuum plasma machine and perform plasma treatment on the surface of the composite to be bonded using the preferred combination of process parameters. Step 3: Place the aluminum alloy substrate on the flame treatment machine frame and flame treat the surface of the aluminum alloy substrate to be bonded with the preferred combination of process parameters. Step 4: Place the adhesive and the surface-treated composite material substrate and aluminum alloy substrate into an oven for preheating; Step 5: After uniformly mixing the preheated adhesive, apply it to the bonding area of ​​the composite material. Then place glass microbeads at the bonding position. Finally, gently place the aluminum alloy on the composite material for bonding and use a clamping device to apply pressure to the bonding position. Step 6: Place the specimen in an oven and heat it. After initial curing, remove the specimen and clean the glue nodules at the joints. After final curing, perform mechanical property testing. By using the processing and setting methods described above, high-performance thermoplastic carbon fiber composite materials and aluminum alloy single-lap joints can be prepared, which are suitable for applications requiring high-strength, high-plasticity, and lightweight joint materials.

2. The method for improving the bonding performance of thermoplastic carbon fiber composite materials with aluminum alloys according to claim 1, characterized in that, In step one, the thermoplastic carbon fiber composite material is a polyamide-based carbon fiber composite material, the aluminum alloy grade is 6082-T6 extruded aluminum alloy, and the substrate size is 100×25×3.0 mm. 3 For grinding composite materials, use 400~800# sandpaper; for grinding aluminum alloys, use 180~400# sandpaper.

3. The method for improving the bonding performance of thermoplastic carbon fiber composite materials with aluminum alloys according to claim 1, characterized in that, In step one, the organic solvent used is isopropanol.

4. The method for improving the bonding performance of thermoplastic carbon fiber composite materials with aluminum alloys according to claim 1, characterized in that, In step one, the drying temperature is 20~35 ºC and the drying time is 10~30 min.

5. The method for improving the bonding performance of thermoplastic carbon fiber composite materials with aluminum alloys according to claim 1, characterized in that, In step two, the gas introduced into the vacuum plasma treatment of the composite material substrate is air, the vacuum degree in the treatment chamber is controlled at -10 to -40 Pa, the power is 100 to 160 W, the gas flow rate is 40 to 80 mL / min, and the treatment time is 250 to 400 s.

6. The method for improving the bonding performance of thermoplastic carbon fiber composite materials with aluminum alloys according to claim 1, characterized in that, In step three, the flame treatment temperature of the aluminum alloy is 1100~1300℃, the distance between the flame nozzle and the specimen is 100~130 mm, and the treatment time is 30-50 s.

7. The method for improving the bonding performance of thermoplastic carbon fiber composite materials with aluminum alloys according to claim 1, characterized in that, In step four, the adhesive is a two-component polyurethane adhesive, and the preheating temperature of the substrate to be bonded and the adhesive is 25~40℃.

8. The method for improving the bonding performance of thermoplastic carbon fiber composite materials with aluminum alloys according to claim 1, characterized in that, In step five, 5-10 glass microbeads are evenly placed in the area to be bonded, and the bonding thickness is controlled at 0.5-1 mm.

9. The method for improving the bonding performance of thermoplastic carbon fiber composite materials with aluminum alloys according to claim 1, characterized in that, In step five, the pressurization method is "F" clamping pressurization.

10. The method for improving the bonding performance of thermoplastic carbon fiber composite materials with aluminum alloys according to claim 1, characterized in that, In step six, the initial curing time of the adhesive is 20-26 hours, the curing temperature is 20-40℃, the subsequent curing time is 7 days, and the curing temperature is 20-30℃.

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