Self-repairing type carbon fiber reinforced metal laminate and microcapsule filling repairing process thereof

Abstract

The invention discloses a self-repairing type carbon fiber reinforced metal laminate and a microcapsule filling repairing process thereof.The self-repairing type carbon fiber reinforced metal laminate is structurally composed of a metal substrate, a carbon fiber layer and microcapsules filled between the metal substrate and the carbon fiber layer, when the laminate is damaged, the microcapsules are broken, a repairing agent flows out and fills a damaged part, and then the self-repairing type carbon fiber reinforced metal laminate is repaired. Self-repairing is achieved, and durability and reliability of the laminate are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite material preparation, and in particular relates to a self-repairing carbon fiber reinforced metal laminate and a microcapsule filling and repairing process thereof. Background Art

[0002] In key equipment sectors such as new energy vehicles and transportation, material performance requirements are increasing. Carbon fiber reinforced metal laminates, as a new type of composite material, offer advantages such as high specific strength and high specific stiffness. However, due to the significant differences in the thermophysical properties of dissimilar materials during use, they are prone to problems such as low interface strength, numerous pore defects, and poor interlayer performance. These problems can easily lead to damage to components when subjected to external forces, impacting their service performance and lifespan. Traditional repair methods typically require external intervention, such as welding and bonding, which are not only complex to operate but can also cause secondary damage to the material itself. Summary of the Invention

[0003] To solve the above problems, the present invention provides a self-repairing carbon fiber reinforced metal laminate, comprising: Metal substrate, made of alloy sheet optimized by heat treatment process, with smooth surface and uniform thickness; The carbon fiber layer is made of carbon fiber prepreg plies, and the ply angle and structure are optimized according to the service performance requirements; The microcapsules are uniformly filled between the metal substrate and the carbon fiber layer. The shell material of the microcapsules is a high molecular polymer and the repair agent is encapsulated inside. The particle size of the microcapsules ranges from 50 to 120 microns and the filling density is 10 to 25 per square centimeter.

[0004] Preferably, the metal substrate is made of aluminum alloy or titanium alloy, and its heat treatment process includes aging treatment and deformation control method to obtain mechanical properties matching strength and plasticity; the shell material of the microcapsule is one of polyurea, polyurethane or their modified derivatives, and the repair agent is one of epoxy resin repair agents or modified epoxy resins.

[0005] Preferably, the surface of the metal substrate is anodized and sprayed with an adhesive, and the adhesive is an epoxy adhesive that has been anodized with phosphoric acid; the carbon fiber layer and the metal substrate are combined by a hot molding process, the hot molding temperature is 150-250°C, the insulation pressure is 5-15MPa, and the mold closing insulation time is 30-120 minutes.

[0006] A microcapsule filling and repair process comprises the following steps: S1. Microcapsule Preparation: Microcapsules are prepared using emulsion polymerization. The shell material is a high molecular weight polymer and the repair agent is encapsulated inside. S2. Microcapsule filling: After spraying adhesive on the metal substrate surface, evenly spread the microcapsules on the adhesive layer, and then lay the carbon fiber prepreg; S3. Hot Pressing: The adhesive is cured through a hot press process, simultaneously securing the microcapsules between the metal substrate and the carbon fiber layer. S4. Release of repair agent: When the laminate is damaged, the microcapsule shell ruptures, the repair agent flows out and fills the damaged area, and solidifies itself at room temperature.

[0007] Preferably, during the preparation of the microcapsules, the mass ratio of the shell material to the repair agent is 1:2 to 1:5; in the hot pressing curing process, the mold heating temperature is 180-220°C, the mold closing insulation pressure is 8-12 MPa, and the insulation time is 60-90 minutes.

[0008] Preferably, the repair agent is a two-component epoxy resin system, comprising a base resin and a curing agent in a mass ratio of 100:(20-40); the microcapsules need to be surface treated before filling to improve the interfacial bonding strength with the adhesive.

[0009] The beneficial effects of the present invention are: Microcapsules containing a repair agent are introduced into carbon fiber reinforced metal laminates. When the laminate is damaged, the microcapsules rupture, allowing the repair agent to flow out and fill the damaged area, achieving self-repair and improving the durability and reliability of the laminate. By optimizing the preparation of microcapsules, the filling process and the selection of repair agents, we ensure that the microcapsules are evenly distributed in the laminates and that the repair agents can be released promptly and effectively when damaged, achieving good repair effects. DETAILED DESCRIPTION

[0010] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Example

[0011] Material selection for metal substrate preparation: 6061-T6 aluminum alloy sheet with a thickness of 1.2 mm and a surface roughness of Ra ≤ 0.8 μm.

[0012] Heat treatment process: Solution treatment: keep at 530℃ for 1 hour and then quench in water to dissolve the alloy elements and form a supersaturated solid solution; Aging treatment: keep at 170℃ for 8 hours to decompose the supersaturated solid solution and precipitate the strengthening phase to obtain mechanical properties of tensile strength ≥310MPa and elongation ≥12%.

[0013] Surface treatment: Anodizing: In a sulfuric acid solution (150g / L), treat at 20V for 20 minutes to form an oxide film with a thickness of 8-12μm, thereby improving the surface roughness of the substrate and the adhesion of the adhesive. Adhesive spraying: Spraying an epoxy adhesive (brand EA9394) that has been anodized with phosphoric acid, with a coating thickness controlled at 30±5μm to ensure a strong bond between the metal substrate and the carbon fiber layer.

[0014] The shell material for microcapsule preparation is a polyurea-polyurethane copolymer with a mass ratio of 7:3, which exhibits excellent flexibility and chemical corrosion resistance. The repair agent is a two-component epoxy resin system with a mass ratio of 100:30 between the base resin E51 and the curing agent D230, which exhibits excellent bonding properties and post-curing strength. The preparation process uses an emulsion polymerization method with a controlled mass ratio of 1:3 between the shell material and the repair agent to ensure the stability of the microcapsules and the release efficiency of the repair agent. The microcapsule particle size is controlled by screening to 90μm, and the filling density is 15 pieces / cm² to meet the self-repair requirements.

[0015] Preparation of carbon fiber layer prepreg layup: T800 grade carbon fiber / epoxy prepreg was selected and laid symmetrically at [0° / 90° / ±45°]s with a total thickness of 0.6mm to optimize the mechanical properties of the laminate; interface treatment: before microcapsule filling, the microcapsule surface was sprayed with silane coupling agent (KH560) to enhance the interface bonding strength with the adhesive.

[0016] Hot press curing process parameters: mold heating temperature: 200°C; mold closing insulation pressure: 10 MPa; insulation time: 75 minutes; operation steps: evenly spread microcapsules on the adhesive layer of the aluminum alloy substrate; lay carbon fiber prepreg and cover with release film; load into the hot press and cure according to the set process parameters; cool to room temperature and demold to obtain a self-healing laminate.

[0017] Performance verification self-repair test: impact damage of 3mm in diameter and 0.2mm in depth was applied to the laminate. The repair agent was cured at 25°C for 24 hours, and the repair efficiency (remaining strength / original strength) reached over 85%. Mechanical properties: interlaminar shear strength ≥ 65MPa, fatigue life (R = 0.1, Δσ = 200MPa) ≥ 1×10 5 times of circulation, meeting the use requirements in aerospace and other fields. Example

[0018] 1. Metal Substrate Preparation Material Selection: TC4 titanium alloy sheet, 1.0 mm thick, with a surface roughness of Ra ≤ 0.6 μm. Heat Treatment: Annealing: 700°C for 2 hours followed by air cooling to eliminate work hardening and improve substrate plasticity. Deformation Control: Grain size is regulated by cold rolling with a 15% deformation to achieve a balance between strength and plasticity. Surface Treatment: Anodizing: 60 V in a 100 g / L phosphoric acid solution for 30 minutes to form an oxide film 5-8 μm thick, enhancing substrate surface activity. Adhesive Spraying: A modified epoxy adhesive (brand FM73) is sprayed to a coating thickness of 25 ± 3 μm to ensure good adhesion to the titanium alloy substrate.

[0019] 2. Optimization of microcapsule filling and repair process Microcapsule parameters: Shell material: A modified polyurethane derivative improves the microcapsule's temperature and chemical resistance; Healing agent: Nanosilica-modified epoxy resin (5wt%) enhances the healer's mechanical properties and curing speed; Particle size range: 60-90μm, packing density: 18 particles / cm², optimizing the self-healing effect; Hot press curing parameters: Mold heating temperature: 180°C; Mold closing and holding pressure: 12MPa; Holding time: 90 minutes to ensure sufficient curing of the adhesive and microcapsules.

[0020] 3. Performance Verification Self-repair test: The laminate was scratched (width 0.5mm, depth 0.1mm). The repair agent cured at room temperature for 48 hours, with a repair efficiency of over 80%. Mechanical properties: interlaminar shear strength ≥ 70MPa, fatigue life (R = 0.1, Δσ = 250MPa) ≥ 8×10 4 cycles, suitable for high stress environments.

[0021] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A self-repairing carbon fiber reinforced metal laminate, characterized in that: include: Metal substrate, made of alloy sheet optimized by heat treatment process, with smooth surface and uniform thickness; The carbon fiber layer is made of carbon fiber prepreg plies, and the ply angle and structure are optimized according to the service performance requirements; The microcapsules are uniformly filled between the metal substrate and the carbon fiber layer. The shell material of the microcapsules is a high molecular polymer and the repair agent is encapsulated inside. The particle size of the microcapsules ranges from 50 to 120 microns and the filling density is 10 to 25 per square centimeter.

2. The self-repairing carbon fiber reinforced metal laminate according to claim 1, characterized in that: The metal substrate is made of aluminum alloy or titanium alloy, and its heat treatment process includes aging treatment and deformation control method to obtain mechanical properties that match strength and plasticity; the shell material of the microcapsule is one of polyurea, polyurethane or their modified derivatives, and the repair agent is one of epoxy resin repair agents or modified epoxy resins.

3. The self-repairing carbon fiber reinforced metal laminate according to claim 2, characterized in that: The surface of the metal substrate is anodized and sprayed with an adhesive, which is an epoxy adhesive that has been anodized with phosphoric acid. The carbon fiber layer and the metal substrate are combined through a hot molding process, with a hot molding temperature of 150-250°C, a holding pressure of 5-15 MPa, and a mold closing and holding time of 30-120 minutes.

4. A microcapsule filling and repairing process for preparing the self-repairing carbon fiber reinforced metal laminate according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Microcapsule Preparation: Microcapsules are prepared using emulsion polymerization. The shell material is a high molecular weight polymer and the repair agent is encapsulated inside. S2. Microcapsule filling: After spraying adhesive on the metal substrate surface, evenly spread the microcapsules on the adhesive layer, and then lay the carbon fiber prepreg; S3. Hot Pressing: The adhesive is cured through a hot press process, simultaneously securing the microcapsules between the metal substrate and the carbon fiber layer. S4. Release of repair agent: When the laminate is damaged, the microcapsule shell ruptures, the repair agent flows out and fills the damaged area, and solidifies itself at room temperature.

5. The microcapsule filling and repairing process according to claim 4, characterized in that: During the preparation of the microcapsules, the mass ratio of the shell material to the repair agent is 1:2 to 1:5; in the hot pressing curing process, the mold heating temperature is 180-220°C, the mold closing insulation pressure is 8-12 MPa, and the insulation time is 60-90 minutes.

6. The microcapsule filling and repairing process according to claim 4, characterized in that: The repair agent is a two-component epoxy resin system, comprising a base resin and a curing agent in a mass ratio of 100:(20-40); the microcapsules need to be surface treated before filling to improve the interfacial bonding strength with the adhesive.