Fiber metal laminate with improved interlaminar shear strength and weather resistance and method of manufacture

Abstract

The application discloses a kind of improving interlaminar shear strength and weather resistance fiber metal laminates and preparation method, belong to composite material preparation field.The application constructs network flocculation nanostructure by improving titanium alloy plate surface treatment method, effectively enhances the interface bonding force of titanium alloy and resin-based fiber composite material.From short beam shear test, the interlaminar shear strength of fiber metal laminates manufactured by the method is increased by 23.6% compared with the sample without treatment on the surface of titanium alloy.After wet heat treatment, the sample manufactured by the method shows better weather resistance, and the interlaminar shear strength after treatment is 42% higher than that of the sample without treatment.The method can be widely applied to the manufacture of Ti / CFRP fiber metal laminates, the bonding of titanium alloy and resin-based fiber composite material, and has strong practical value.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation, specifically relating to a fiber-metal laminate and its preparation method for improving interlaminar shear strength and weather resistance. Background Technology

[0002] Fiber-reinforced metal laminates are manufactured by alternating layers of metal and fiber-reinforced composite materials and then curing them through hot pressing. Compared to traditional single-material composites such as aluminum alloys, titanium alloys, and resin fiber-reinforced composites, fiber-reinforced metal laminates combine the advantages of both materials, exhibiting high strength, high modulus, and lightweight properties, as well as corrosion resistance, high toughness, and excellent impact resistance, making them widely used in the aerospace field. Fiber-reinforced metal laminates were first proposed by researchers at Delft University and have since evolved through four generations. Compared to the first-generation aramid-reinforced aluminum alloy laminates, the second-generation glass fiber-reinforced aluminum alloy laminates, and the third-generation carbon fiber-reinforced aluminum alloy laminates, the fourth-generation fiber-reinforced metal laminates have solved the electrochemical corrosion problem between aluminum alloys and carbon fibers. Furthermore, the superior strength of titanium alloys compared to aluminum alloys significantly improves the mechanical properties of titanium alloy / carbon fiber laminates, demonstrating excellent application prospects.

[0003] Although fiber-reinforced metal laminates (FRPs) offer significant advantages over traditional single-material composites, the numerous alternating interlayer interfaces—including the resin-fiber interface, interlayer interfaces within the CFRP, and the metal-resin interface between the CFRP and the titanium plate—make delamination a common problem during application. The metal-resin interface generally exhibits the weakest bond strength, making improving the metal-resin adhesion strength a crucial step in laminate manufacturing. The metal-resin adhesion strength is primarily determined by factors such as the metal surface morphology, the wettability of the metal and resin, and their bonding ability. Titanium plate surface treatment methods can be broadly categorized into three types based on their processes: mechanical treatments such as mechanical grinding, shot peening, and sandblasting; chemical treatments such as chemical passivation, anodizing, and surface chemical etching; and methods involving adding a coupling interface layer between the metal and resin. Current research largely focuses on improving the metal surface roughness, but the improvement in interfacial adhesion remains insufficient and requires further refinement. Summary of the Invention

[0004] The purpose of this invention is to overcome the deficiencies in the prior art and provide a fiber-reinforced metal laminate with improved interlaminar shear strength and weather resistance, as well as a method for its preparation. This invention starts by improving the microstructure of titanium alloy surfaces, constructing a network-like flocculent nanostructure, which effectively improves the interlaminar shear strength and weather resistance of the fiber-reinforced metal laminate.

[0005] The specific technical solution adopted in this invention is as follows:

[0006] In a first aspect, the present invention provides a method for preparing a fiber-reinforced metal laminate with improved interlaminar shear strength and weather resistance, as detailed below:

[0007] The pretreated titanium alloy is anodized using an electrolyte, then washed and dried. The anodized titanium alloy is then subjected to stress-relief annealing, followed by spraying a resin film onto its surface. The titanium alloy and carbon fiber prepreg are laid in a layering sequence of [M / P / M / P / M / … / P / M] and pre-compacted. After hot pressing and curing, the fiber-metal laminate is formed, where M represents the titanium alloy and P represents a single or multiple layers of carbon fiber prepreg.

[0008] Preferably, the electrolyte is a mixture of ammonium fluoride, deionized water and ethylene glycol in a mass ratio of 1:5:94.

[0009] Preferably, the pretreatment method for the titanium alloy is as follows:

[0010] The titanium alloy is first mechanically ground to remove surface oil stains, then washed and dried; subsequently, the surface of the titanium alloy is acid-washed to remove the surface oxide film, then washed and dried.

[0011] Furthermore, the pickling solution used in the pickling process is a mixture of hydrofluoric acid and nitric acid in a volume ratio of 1:3, and the pickling time is 40 seconds.

[0012] Preferably, the voltage during the anodizing process is 30V and the processing time is 5min.

[0013] Preferably, in the stress-relief annealing process, the temperature is raised from room temperature to 500°C at a rate of 5°C / min, held for 15 minutes, and then cooled in the furnace.

[0014] Preferably, the resin film is formed by spraying a solution of structural adhesive film onto the surface of the titanium alloy.

[0015] Furthermore, the spraying density is 40 g / m³. 2 The spraying pressure is 1.6 bar.

[0016] Preferably, during the hot pressing process, the temperature is raised from room temperature to 80°C at a rate of 0.5°C / min and held for 60 min, then raised to 120°C at a rate of 0.5°C / min and held for 120 min, and finally lowered to room temperature at a rate of 1.5°C / min, with the pressure maintained at 6.6 bar throughout the process.

[0017] In a second aspect, the present invention provides a fiber-metal laminate with improved interlaminar shear strength and weather resistance obtained by any of the preparation methods described in the first aspect.

[0018] By means of the above scheme, the invention has at least the following advantages: On the one hand, the titanium alloy surface treated by this method has a network of flocculent nanostructures, which can not only uniformly and effectively improve the interfacial bonding force of the fiber metal laminate and enhance the interlaminar shear strength, but also improve the weather resistance of the fiber metal laminate; on the other hand, the steps described in this method are not only applicable to flat parts, but also to simple irregular parts, and have a wide range of applications.

[0019] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the following describes in detail a method for preparing a fiber metal laminate with improved interlaminar shear strength and weather resistance provided by the present invention, in conjunction with the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This is a SEM image of the processed titanium alloy surface in an embodiment of the present invention;

[0021] Figure 2 The image shown is an AFM image of the treated titanium alloy surface in an embodiment of the present invention.

[0022] Figure 3 The interlaminar shear strength of fiber-reinforced metal laminates prepared with different surface treatments in the embodiments and comparative examples of the present invention;

[0023] Figure 4 The variation in moisture absorption rate of the fiber-metal laminate in the embodiments and comparative examples of the present invention;

[0024] Figure 5 This refers to the interlaminar shear strength of the fiber-metal laminate after hygrothermal treatment in the embodiments and comparative examples of the present invention. Detailed Implementation

[0025] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly, provided that there is no mutual conflict.

[0026] This invention provides a method for preparing fiber-reinforced metal laminates with improved interlaminar shear strength and weather resistance. The specific preparation method is as follows:

[0027] First, the pre-treated titanium alloy is anodized using a specific electrolyte solution. After rinsing with water, it is dried in an oven. The anodized titanium alloy undergoes stress-relief annealing, followed by spraying a resin film onto its surface. The titanium alloy and carbon fiber prepreg are then laid in a [M / P / M / P / M / … / P / M] layering sequence and pre-compacted. After hot pressing and curing, a fiber-metal laminate is formed, where M represents the titanium alloy and P represents single or multiple layers of carbon fiber prepreg.

[0028] In practical applications, the electrolyte can be a mixture of ammonium fluoride, deionized water, and ethylene glycol in a mass ratio of 1:5:94.

[0029] In practical applications, the pretreatment methods for titanium alloys are as follows:

[0030] First, the titanium alloy is mechanically polished to remove surface oil stains, rinsed with clean water, and then dried in an oven. Next, the titanium alloy surface is pickled to remove the surface oxide film, rinsed with clean water, and then dried in an oven. Specifically, the pickling solution used is a mixture of hydrofluoric acid and nitric acid in a 1:3 volume ratio, and the pickling time is controlled to be approximately 40 seconds.

[0031] In actual use, the voltage should be maintained at around 30V during the anodizing process, and the anodizing time should be controlled at around 5 minutes.

[0032] In actual use, the annealing process starts from room temperature and heats to 500°C at a rate of 5°C / min, then holds at that temperature for about 15 minutes, and finally cools down with the furnace.

[0033] In practical applications, the resin film used is formed by uniformly spraying a solution of structural adhesive film onto the titanium alloy surface under high pressure. Specifically, the spraying density is controlled at 40 g / m². 2 The spraying pressure is controlled at around 1.6 bar.

[0034] In actual use, the equipment for hot pressing curing is an autoclave. The hot pressing process starts from room temperature and heats to 80°C at a rate of 0.5°C / min, then holds for 60 minutes. Then it continues to heat to 120°C at a rate of 0.5°C / min and holds for 120 minutes. Finally, it cools to room temperature at a rate of 1.5°C / min. The pressure is maintained at around 6.6 bar throughout the process.

[0035] The preparation method and effects of the material of the present invention will be specifically described below with reference to the embodiments and comparative examples.

[0036] Example

[0037] This embodiment provides a method for preparing fiber-reinforced metal laminates with improved interlaminar shear strength and weather resistance. The steps of this method are as follows:

[0038] S1: First, mechanically grind the TA2 titanium alloy to remove surface oil stains, rinse with clean water, and then place it in an oven to dry. In this step, the clean water is deionized water, and the washing operations before drying in the following steps are also performed with deionized water.

[0039] S2: The titanium alloy surface treated in step S1 is pickled to remove the surface oxide film. After rinsing with clean water, it is placed in an oven to dry. In this step, the pickling solution is a mixture of hydrofluoric acid and nitric acid in a volume ratio of 1:3. During pickling, appropriate stirring is performed. The front side is pickled for 20 seconds, then flipped and pickled for another 20 seconds, with the total time controlled at approximately 40 seconds. In addition, a large amount of orange-red gas, NO2, will be released during the pickling process; operators should take appropriate protective measures.

[0040] S3: The titanium alloy treated in step S2 is anodized using an electrolyte solution with a specific ratio. After rinsing with clean water, it is dried in an oven. In this step, the electrolyte solution is a mixture of ammonium fluoride, deionized water, and ethylene glycol in a mass ratio of 1:5:94. Graphite or the untreated titanium alloy is used as the cathode, and the titanium alloy to be treated is used as the anode. The anodizing process is carried out at room temperature, with the voltage maintained at approximately 30V and the time controlled at approximately 5 minutes.

[0041] S4: Perform stress-relief annealing on the titanium alloy treated in step S3. In this step, the annealing process starts from room temperature, heats to 500°C at a rate of 5°C / min, holds at that temperature for about 15 minutes, and finally cools in the furnace. The titanium alloy after the above treatment should complete the subsequent spraying and curing operations within 24 hours to avoid failure of the titanium alloy surface treatment.

[0042] S5: A resin film is sprayed onto the titanium alloy surface after step S4. In this step, the resin film is formed by uniformly spraying a solution of structural adhesive film onto the titanium alloy surface under high pressure. The solvent is dichloromethane, and the structural adhesive film is J272 adhesive film. The spraying density is controlled at 40 g / m³. 2 The spraying pressure should be controlled at around 1.6 bar. After spraying and drying, the coating should be laid down and cured immediately, or stored properly to prevent dust and impurities from falling onto the titanium alloy surface.

[0043] S6: The titanium alloy treated in step S5 and the carbon fiber prepreg are laid out and pre-compacted in the sequence [Ti / 0 / 90 / Ti / 0 / 90 / Ti / 90 / 0 / Ti / 90 / 0 / Ti], and then hot-pressed and cured to form a fiber-metal laminate. Here, Ti represents TA2 titanium alloy, 0 represents a single layer of carbon fiber prepreg with fibers along the 0° direction, and 90 represents a single layer of carbon fiber prepreg with fibers along the 90° direction. In this step, the hot-pressing equipment is an autoclave. The hot-pressing process starts at room temperature, heating to 80°C at a rate of 0.5°C / min and holding for 60 minutes, then continuing to heat to 120°C at a rate of 0.5°C / min and holding for 120 minutes, finally cooling to room temperature at a rate of 1.5°C / min, with the pressure maintained at approximately 6.6 bar throughout the process.

[0044] S7: Short beam shear samples were fabricated from the prepared fiber-reinforced metal laminate and tested. The interlaminar shear strength was found to be 55.6 MPa. In this step, the fiber-reinforced metal laminate thickness was 2.8 mm, and its length and width were determined to be 22 × 12 mm according to standard GB / T 35100-2018. The short beam shear samples were obtained after wire cutting. The sample length direction was along the 0° fiber direction of the outermost CFRP layer of the fiber-reinforced metal laminate.

[0045] S8: After hydrothermal treatment of the short beam shear sample, a second short beam shear test was conducted, yielding an interlaminar shear strength of 43.2 MPa. In this step, the hydrothermal treatment equipment was a water bath at 80°C and 100% humidity. The final moisture absorption rate was 0.42% after two consecutive changes in moisture loss were less than 0.02%. The sample testing standards, dimensions, processing method, and orientation were the same as in S7.

[0046] Comparative Example 1

[0047] The difference between this comparative example and the embodiment is that step S3 is omitted. The steps of this method are as follows:

[0048] S1: First, mechanically grind the TA2 titanium alloy to remove surface oil stains, rinse with clean water, and then place it in an oven to dry. In this step, the clean water is deionized water, and the washing operations before drying in the following steps are also performed with deionized water.

[0049] S2: Pickling is performed on the titanium alloy surface treated in step S1 to remove the surface oxide film. After rinsing with clean water, it is placed in an oven to dry. In this step, the pickling solution is a mixture of hydrofluoric acid and nitric acid with a volume ratio of 1:3. Appropriate stirring is performed during pickling. The front side is pickled for 20 seconds, then flipped and pickled for another 20 seconds, with the total time controlled at approximately 40 seconds. In addition, a large amount of orange-red gas, NO2, will be released during the pickling process; operators should take appropriate protective measures.

[0050] S3: Perform stress-relief annealing on the titanium alloy treated in step S2. In this step, the annealing process starts from room temperature, heats to 500°C at a rate of 5°C / min, holds at that temperature for about 15 minutes, and finally cools in the furnace. The titanium alloy after the above treatment should complete the subsequent spraying and curing operations within 24 hours to avoid failure of the titanium alloy surface treatment.

[0051] S4: A resin film is sprayed onto the titanium alloy surface after step S3. In this step, the resin film is formed by uniformly spraying a solution of the structural adhesive film onto the titanium alloy surface under high pressure. The solvent is dichloromethane, and the structural adhesive film is J272 adhesive film. The spraying density is controlled at 40 g / m³. 2 The spraying pressure should be controlled at around 1.6 bar. After spraying and drying, the coating should be laid down and cured immediately, or stored properly to prevent dust and impurities from falling onto the titanium alloy surface.

[0052] S5: The titanium alloy treated in step S4 and the carbon fiber prepreg are laid out and pre-compacted in the sequence [Ti / 0 / 90 / Ti / 0 / 90 / Ti / 90 / 0 / Ti / 90 / 0 / Ti], and then hot-pressed and cured to form a fiber-metal laminate. Ti represents TA2 titanium alloy, 0 represents a single layer of carbon fiber prepreg with fibers along the 0° direction, and 90 represents a single layer of carbon fiber prepreg with fibers along the 90° direction. In this step, the hot-pressing equipment is an autoclave. The hot-pressing process starts at room temperature, heating to 80°C at a rate of 0.5°C / min and holding for 60 minutes, then continuing to heat to 120°C at a rate of 0.5°C / min and holding for 120 minutes, finally cooling to room temperature at a rate of 1.5°C / min, with the pressure maintained at approximately 6.6 bar throughout the process.

[0053] S6: Short beam shear samples were fabricated from the prepared fiber-reinforced metal laminate and tested. The interlaminar shear strength was found to be 45 MPa. In this step, the fiber-reinforced metal laminate thickness was 2.8 mm, and its length and width were determined to be 22 × 12 mm according to standard GB / T35100-2018. The short beam shear samples were obtained after wire cutting. The sample length direction was along the 0° fiber direction of the outermost CFRP layer of the fiber-reinforced metal laminate.

[0054] S7: After hydrothermal treatment of the short beam shear sample, a second short beam shear test was conducted, yielding an interlaminar shear strength of 30.4 MPa. In this step, the hydrothermal treatment equipment was a water bath at 80°C and 100% humidity. The final moisture absorption rate was 0.34% after two consecutive changes in moisture loss were less than 0.02%. The sample testing standards, dimensions, processing method, and orientation were the same as in S6.

[0055] Comparative Example 2

[0056] The difference between this comparative example and the embodiment is that step S3, anodizing, is replaced by sandblasting, and step S2 is omitted. The steps of this method are as follows:

[0057] S1: First, mechanically grind the TA2 titanium alloy to remove surface oil stains, rinse it with clean water, and then place it in an oven to dry. In this step, the clean water is deionized water.

[0058] S2: The titanium alloy treated in step S1 is then sandblasted. In this step, a pressure-feed sandblasting machine is used, employing 150-mesh bauxite sand. The sand is evenly blown onto the surface of the titanium alloy plate under a spray gun pressure of 0.6 MPa for 30 seconds, until the surface achieves a matte finish. After treatment, the sample is removed for later use.

[0059] S3: Perform stress-relief annealing on the titanium alloy treated in step S2. In this step, the annealing process starts from room temperature, heats to 500°C at a rate of 5°C / min, holds at that temperature for about 15 minutes, and finally cools in the furnace. The titanium alloy after the above treatment should complete the subsequent spraying and curing operations within 24 hours to avoid failure of the titanium alloy surface treatment.

[0060] S4: A resin film is sprayed onto the titanium alloy surface after step S3. In this step, the resin film is formed by uniformly spraying a solution of the structural adhesive film onto the titanium alloy surface under high pressure. The solvent is dichloromethane, and the structural adhesive film is J272 adhesive film. The spraying density is controlled at 40 g / m³. 2 The spraying pressure should be controlled at around 1.6 bar. After spraying and drying, the coating should be laid down and cured immediately, or stored properly to prevent dust and impurities from falling onto the titanium alloy surface.

[0061] S5: The titanium alloy treated in step S4 and the carbon fiber prepreg are laid out and pre-compacted in the sequence [Ti / 0 / 90 / Ti / 0 / 90 / Ti / 90 / 0 / Ti / 90 / 0 / Ti], and then hot-pressed and cured to form a fiber-metal laminate. Ti represents TA2 titanium alloy, 0 represents a single layer of carbon fiber prepreg with fibers along the 0° direction, and 90 represents a single layer of carbon fiber prepreg with fibers along the 90° direction. In this step, the hot-pressing equipment is an autoclave. The hot-pressing process starts at room temperature, heating to 80°C at a rate of 0.5°C / min and holding for 60 minutes, then continuing to heat to 120°C at a rate of 0.5°C / min and holding for 120 minutes, finally cooling to room temperature at a rate of 1.5°C / min, with the pressure maintained at approximately 6.6 bar throughout the process.

[0062] S6: Short beam shear samples were fabricated from the prepared fiber-reinforced metal laminate and tested. The interlaminar shear strength was found to be 48.5 MPa. In this step, the fiber-reinforced metal laminate thickness was 2.8 mm, and its length and width were determined to be 22 × 12 mm according to standard GB / T 35100-2018. The short beam shear samples were obtained after wire cutting. The sample length direction was along the 0° fiber direction of the outermost CFRP layer of the fiber-reinforced metal laminate.

[0063] S7: After hydrothermal treatment of the short beam shear sample, a second short beam shear test was conducted, yielding an interlaminar shear strength of 37.7 MPa. In this step, the hydrothermal treatment equipment was a water bath at 80°C and 100% humidity. The final moisture absorption rate was 0.26% after two consecutive changes in moisture loss were less than 0.02%. The sample testing standards, dimensions, processing method, and orientation were the same as in S6.

[0064] Comparative Example 3

[0065] The difference between this comparative example and the embodiment is that step S3, the anodic oxidation method, is replaced by the traditional NaTESi anodic oxidation method, the steps of which are as follows:

[0066] S1: First, mechanically grind the TA2 titanium alloy to remove surface oil stains, rinse with clean water, and then place it in an oven to dry. In this step, the clean water is deionized water, and the washing operations before drying in the following steps are also performed with deionized water.

[0067] S2: The titanium alloy surface treated in step S1 is pickled to remove the surface oxide film. After rinsing with clean water, it is placed in an oven to dry. In this step, the pickling solution is a mixture of hydrofluoric acid and nitric acid in a volume ratio of 1:3. During pickling, appropriate stirring is performed. The front side is pickled for 20 seconds, then flipped and pickled for another 20 seconds, with the total time controlled at approximately 40 seconds. In addition, a large amount of orange-red gas, NO2, will be released during the pickling process; operators should take appropriate protective measures.

[0068] S3: The titanium alloy treated in step S2 is anodized using an electrolyte solution with a specific ratio. After rinsing with clean water, it is dried in an oven. In this step, the electrolyte is a traditional NaTESi electrolyte (i.e., NaOH 7.5M / L, Na2SiO3·9H2O 0.05M / L, Na2C4H4O6·2H2O 0.33M / L, EDTA 0.07M / L). Graphite or the untreated titanium alloy is used as the cathode, and the titanium alloy to be treated is used as the anode. The anodizing process is carried out at room temperature, with the voltage maintained at approximately 10V and the time controlled at approximately 20 minutes.

[0069] S4: Perform stress-relief annealing on the titanium alloy treated in step S3. In this step, the annealing process starts from room temperature, heats to 500°C at a rate of 5°C / min, holds at that temperature for about 15 minutes, and finally cools in the furnace. The titanium alloy after the above treatment should complete the subsequent spraying and curing operations within 24 hours to avoid failure of the titanium alloy surface treatment.

[0070] S5: A resin film is sprayed onto the titanium alloy surface after step S4. In this step, the resin film is formed by uniformly spraying a solution of the structural adhesive film onto the titanium alloy surface under high pressure. The solvent is dichloromethane, and the structural adhesive film is J272 adhesive film. The spraying density is controlled at 40 g / m³. 2 The spraying pressure should be controlled at around 1.6 bar. After spraying and drying, the coating should be laid down and cured immediately, or stored properly to prevent dust and impurities from falling onto the titanium alloy surface.

[0071] S6: The titanium alloy treated in step S5 and the carbon fiber prepreg are laid out and pre-compacted in the layup sequence [Ti / 0 / 90 / Ti / 0 / 90 / Ti / 90 / 0 / Ti / 90 / 0 / Ti], and then hot-pressed and cured to form a fiber-metal laminate. Ti represents TA2 titanium alloy, 0 represents a single layer of carbon fiber prepreg with fibers along the 0° direction, and 90 represents a single layer of carbon fiber prepreg with fibers along the 90° direction. In this step, the hot-pressing equipment is an autoclave. The hot-pressing process starts at room temperature, heating to 80°C at a rate of 0.5°C / min and holding for 60 min, then continuing to heat to 120°C at a rate of 0.5°C / min and holding for 120 min, finally cooling to room temperature at a rate of 1.5°C / min, with the pressure maintained at approximately 6.6 bar throughout the process.

[0072] S7: Short beam shear samples were fabricated from the prepared fiber-reinforced metal laminate and tested. The interlaminar shear strength was found to be 53.8 MPa. In this step, the fiber-reinforced metal laminate thickness was 2.8 mm, and its length and width were determined to be 22 × 12 mm according to standard GB / T 35100-2018. The short beam shear samples were obtained after wire cutting. The sample length direction was along the 0° fiber direction of the outermost CFRP layer of the fiber-reinforced metal laminate.

[0073] S8: After the short beam shear sample underwent hydrothermal treatment, a second short beam shear test was performed, yielding an interlaminar shear strength of 42.5 MPa. In this step, the hydrothermal treatment equipment was a water bath at 80°C and 100% humidity. The final moisture absorption rate was 0.26% after two consecutive changes in moisture loss were less than 0.02%. The sample testing standards, dimensions, processing method, and orientation were the same as in S7.

[0074] The following example, using the surface treatment preparation process in the embodiment, illustrates the specific technical effects of the present invention. In the embodiment, an anodizing improvement operation was performed on the titanium alloy surface, and the SEM image of the surface morphology of the treated titanium alloy is shown below. Figure 1 As shown, a network of flocculent nanostructures was constructed; the AFM image of the treated titanium alloy surface is shown below. Figure 2 As shown, synapses are formed on the surface of the titanium alloy, which effectively enhances the mechanical adhesion between the titanium alloy and the resin, improving the bonding strength between the metal and the resin, thereby strengthening the interfacial bonding force. From the short beam shear test, the fiber-reinforced metal laminate prepared by the improved anodizing method of this invention showed a 23.6% increase in interlaminar shear strength compared to the untreated titanium alloy laminate (Comparative Example 1), and also showed increases of 14.8% and 3.4% compared to the mechanically treated sandblasting method (Comparative Example 2) and the traditional NaTESi anodizing method (Comparative Example 3), respectively. The results are as follows... Figure 3 As shown.

[0075] The changes in moisture absorption rate of fiber-metal laminates in the examples and comparative examples are as follows: Figure 4 As shown, although the sample manufactured in this embodiment exhibits the highest moisture absorption rate after hydrothermal treatment, this is mainly because the network-like flocculent nanostructure provides more space for moisture. However, the presence of this structure still effectively binds the titanium alloy and resin interface, thus demonstrating better weather resistance. The interlaminar shear strength of the treated sample is 42% higher than that of the untreated sample, as shown in the results. Figure 5 As shown.

[0076] In summary, this invention proposes a method for preparing fiber-metal laminates that improves interlaminar shear strength and weather resistance. The constructed network flocculent nanostructure can not only uniformly and effectively improve the interfacial bonding force of the fiber-metal laminate and enhance the interlaminar shear strength, but also improve the weather resistance of the fiber-metal laminate.

[0077] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A method for preparing a fiber-reinforced metal laminate with improved interlaminar shear strength and weather resistance, characterized in that, Specifically as follows: The pretreated titanium alloy is anodized using an electrolyte, then washed and dried. The anodized titanium alloy undergoes stress-relief annealing, followed by spraying a resin film onto its surface. The titanium alloy and carbon fiber prepreg are then laid in a [M / P / M / P / M / … / P / M] layering sequence and pre-compacted. After hot pressing and curing, a fiber-metal laminate is obtained. Here, M represents the titanium alloy, and P represents a single or multiple layers of carbon fiber prepreg. The surface of the titanium alloy after anodizing forms a network of flocculent nanostructures; the electrolyte is a mixture of ammonium fluoride, deionized water and ethylene glycol in a mass ratio of 1:5:94; during the anodizing process, the voltage is 30V and the treatment time is 5min; during the stress-relief annealing process, the temperature is raised from room temperature to 500℃ at a rate of 5℃ / min and held for 15min, and finally cooled in the furnace.

2. The method for preparing fiber-reinforced metal laminate with improved interlaminar shear strength and weather resistance according to claim 1, characterized in that, The pretreatment method for the titanium alloy is as follows: The titanium alloy is first mechanically ground to remove surface oil stains, then washed and dried; subsequently, the surface of the titanium alloy is acid-washed to remove the surface oxide film, then washed and dried.

3. The method for preparing fiber-reinforced metal laminate with improved interlaminar shear strength and weather resistance according to claim 2, characterized in that, The pickling solution used in the pickling process is a mixture of hydrofluoric acid and nitric acid with a volume ratio of 1:3, and the pickling time is 40 seconds.

4. The method for preparing fiber-reinforced metal laminate with improved interlaminar shear strength and weather resistance according to claim 1, characterized in that, The resin film is formed by spraying a solution of structural adhesive film onto the surface of a titanium alloy.

5. The method for preparing fiber-reinforced metal laminate with improved interlaminar shear strength and weather resistance according to claim 4, characterized in that, The spraying density is 40 g / m³ 2 The spraying pressure is 1.6 bar.

6. The method for preparing fiber-reinforced metal laminate with improved interlaminar shear strength and weather resistance according to claim 1, characterized in that, During the hot pressing process, the temperature is raised from room temperature to 80°C at a rate of 0.5°C / min and held for 60 minutes. Then, the temperature is raised to 120°C at a rate of 0.5°C / min and held for 120 minutes. Finally, the temperature is lowered to room temperature at a rate of 1.5°C / min, and the pressure is maintained at 6.6 bar throughout the process.

7. A fiber-reinforced metal laminate with improved interlaminar shear strength and weather resistance, obtained by any of the preparation methods described in claims 1 to 6.

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