CN117774340B - Preparation method of microcapsule strong pinning metal/carbon fiber composite material joint - Google Patents

Abstract

The invention belongs to the technical field of preparation of structural members of metal/CFRTP, and particularly relates to a preparation method of a microcapsule strong pinning metal/carbon fiber composite material joint. Aiming at the problems that the two materials are difficult to be compatible and a high-quality metal/CFRTP connecting component cannot be formed when the traditional metal/CFRTP structural component is prepared in a compounding way, and particularly aiming at ultrasonic welding of the metal/CFRTP, the invention adds a laser processing metal surface microstructure, a silane coupling agent and microcapsule implantation on the basis of the traditional ultrasonic welding process so as to further improve the mechanical locking and chemical bonding strength of a metal and carbon fiber connecting joint.

Description

A method for preparing a microcapsule strong pinning metal/carbon fiber composite material joint

Technical Field

The invention belongs to the technical field of metal/CFRTP structural parts preparation, and in particular relates to a method for preparing a microcapsule strong-pinning metal/carbon fiber composite material joint.

Background technique

Carbon fiber composite materials (CFRP) have a series of excellent properties such as light weight and high strength, and play an extremely important role in the development of national defense science and technology, weapons and equipment, civil aviation, mechanical transportation and other fields. In particular, carbon fiber composite materials are widely used in weapons and equipment with lightweight requirements such as rockets, aircraft, vehicles, and missiles, and the trend is gradually increasing. In addition, metal alloys are still the main lightweight materials at present. The composite connection of metal and carbon fiber composite materials can give full play to the respective advantages of metal materials and carbon fiber composite materials. It is also an important requirement for the manufacturing of complex engineering components and the integration of product structure and function.

As a type of carbon fiber composite material, thermoplastic carbon fiber composite material (CFRTP) is weldable and recyclable. Compared with thermosetting carbon fiber composite material (CFRTS), CFRTP and metal have more abundant connection methods, mainly including bonding, mechanical fastening and welding. However, traditional connection technology has many disadvantages. Bonding technology is affected by curing time and environmental sensitive factors, and mechanical fastening technology has problems such as stress concentration. With the development of welding technology, connection technologies such as laser welding, stir friction welding, resistance welding and ultrasonic welding are gradually applied to the preparation of metal/CFRTP structural parts. Among them, ultrasonic welding technology has the characteristics of short welding time and low energy input compared with other welding technologies. However, under the traditional ultrasonic welding process, due to the poor compatibility of metal and CFRTP materials and weak interface adsorption, the two cannot be tightly connected. Such problems cannot be further improved by simply changing process parameters and material surface conditions.

In order to solve the problem that metal/CFRTP are difficult to connect, surface treatment is usually used to change the state of the interface to be connected between the two, so as to improve the connection effect between the two. However, no matter whether mechanical treatment or chemical treatment is used, it is still necessary to compound two dissimilar materials with extremely poor compatibility, metal and CFRTP. Therefore, it becomes possible to achieve the connection of metal/CFRTP by adding an intermediate medium, which places stringent requirements on the intermediate medium and needs to be able to meet the high compatibility of metal and CFRTP at the same time. Therefore, the present invention proposes to embed resin-based microcapsules on the metal surface, which can solve this problem well and further enhance the connection effect of metal and CFRTP.

Summary of the invention

The present invention aims to solve the problem that in the composite preparation of existing metal/CFRTP structural parts, the two materials are difficult to be compatible and high-quality metal/CFRTP connecting components cannot be formed, especially for ultrasonic welding of metal/CFRTP. On the basis of traditional ultrasonic welding technology, the present invention adds laser processing of metal surface microstructure, silane coupling agent and microcapsule implantation to further improve the mechanical locking and chemical bonding strength of the metal and carbon fiber connection joints.

To achieve the above object, the present invention adopts the following technical solutions:

A method for preparing a microcapsule strong pinning metal/carbon fiber composite material joint comprises the following steps:

Step 1, selecting plates: selecting the required metal plates and carbon fiber composite plates, and processing the metal plates and carbon fiber composite plates into the actual required shapes and sizes;

Step 2, plate surface treatment: removing oil stains and oxide films on the surface of metal plates and carbon fiber composite plates;

Step 3, laser processing of the metal plate surface: performing laser drilling on the surface-treated metal plate to produce a micron-level porous structure;

Step 4, silane coupling agent modification of the metal plate surface: a silane coupling agent is attached to the surface of the metal plate after laser processing, and a high-temperature modification treatment is performed;

Step 5, microcapsule preparation: adding a polymer resin material to a solvent, stirring evenly, and then adding an emulsifier to form a uniform encapsulation liquid, then immersing the chopped fiber bundle in the encapsulation liquid, cooling and solidifying with liquid nitrogen, separating the solvent, and drying to obtain a resin-based microcapsule encapsulating the chopped fiber bundle;

Step 6, microcapsule embedding: embedding the resin-based microcapsules encapsulating the chopped fiber bundles into the micron-scale porous structure on the modified metal plate;

Step 7, ultrasonic welding: the surface treated carbon fiber composite material plate and the metal plate with embedded microcapsules are stacked and fixed in a single-side overlap manner to be connected, and ultrasonic welding is performed;

Step 8: Cool the finished product.

Furthermore, the material of the metal plate in step 1 is aluminum alloy, magnesium alloy or stainless steel.

Furthermore, in step 2, anhydrous ethanol is used for the surface treatment of the plate.

Furthermore, in step 3, the metal plate surface laser processing adopts a nanosecond laser processing system, and the parameters of the nanosecond laser processing system are set as follows: speed is 200-500 mm/s, frequency is 25 kHz, and power is 75-155 W.

Furthermore, in step 3, the width or diameter of the micron-scale porous structure is 300-400 μm, and the depth is 200-600 μm.

Furthermore, the specific steps of modifying the metal plate surface with a silane coupling agent in step 4 are:

The metal plate is completely soaked with clean water to produce a seamless water film, and then immediately immersed in the silane coupling agent for 1 to 2 minutes; after the metal plate is taken out, the surface water film is dried, and then maintained at a high temperature of 120°C for 20 minutes to complete the silane coupling agent modification of the metal plate surface.

Furthermore, the silane coupling agent in step 4 is KH-550 type silane coupling agent.

Furthermore, in step 5, the polymer resin material is nylon or polyetheretherketone. When the polymer resin material is nylon, formic acid is selected as the solvent, and a phospholipid emulsifier with a mass fraction of 1% is selected as the emulsifier. The weight percentages of nylon, chopped fiber bundles, formic acid and phospholipid emulsifier are 40%:10%:20%:30%. When the polymer resin material is polyetheretherketone, dichloromethane is selected as the solvent, and a polyvinyl alcohol emulsifier with a mass fraction of 5% is selected as the emulsifier. The weight percentages of polyetheretherketone, chopped fiber bundles, dichloromethane and polyvinyl alcohol emulsifier are 40%:5%:25%:30%.

Furthermore, the resin-based microcapsules that embed the chopped fiber bundles in step 5 are spherical microcapsules with a diameter of 80 to 150 μm.

Furthermore, in step 7, the ultrasonic welding is performed on an ultrasonic welding device, and the parameters of the ultrasonic welding device are set as follows: rated power of 4 kW, rated frequency of 20 kHz, maximum welding amplitude of 52 μm, welding time of 2500-4000 ms, and welding pressure of 0.3-0.6 MPa.

Compared with the prior art, the present invention has the following advantages:

1. When using the traditional ultrasonic welding method, the high viscosity of the resin in the molten state causes the movement of the chopped carbon fiber bundles to be hindered and unable to enter the holes on the surface of the metal plate. The present invention uses laser processing technology to process the metal plate surface into a micron-level porous structure, and embeds the resin-based microcapsules that embed the chopped carbon fibers into the micron-level porous structure on the surface of the metal plate. During the ultrasonic welding process, the resin film on the surface of the microcapsules is melted at high temperature, and the chopped carbon fiber bundles in the microcapsules are released, forming a significant pinning effect; under the action of pressure, the melted resin of the carbon fiber composite material plate is filled into the micron-level porous structure on the surface of the metal plate, and is melted with the melted resin film on the surface of the microcapsules, squeezing the melted microcapsules into close contact with the metal plate, and at the same time helps the resin to wet and spread on the surface of the metal plate, providing a favorable environment for the chemical bonding reaction at the connection interface of the metal/carbon fiber composite material, and forming a firm and reliable connection joint. It can be applied to the joint connection of simple structural parts such as L-shaped and T-shaped parts and complex structural parts such as lattices.

2. The present invention is a microcapsule-assisted metal/carbon fiber composite material strong pinning ultrasonic welding, which has the characteristics of good interface connection strength.

3. The laser processing microstructure and microcapsule embedding technology adopted by the present invention are advanced, reasonable, feasible, and can be used for the composite preparation of high-strength and high-quality metal/CFRTP structural parts.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a microscopic morphology of the connection interface of the metal/carbon fiber composite material joint in Example 1;

FIG2 is a morphology of a micrometer-scale porous structure obtained by laser processing in Example 1;

FIG3 is a three-dimensional profile image of a micrometer-scale porous structure obtained by laser processing in Example 1;

FIG4 is a microscopic morphology of the metal/carbon fiber composite material joint connection interface without embedded microcapsules.

Detailed ways

In order to further illustrate the technical solution of the present invention, the present invention is further described below through embodiments.

Example 1

A method for preparing a microcapsule strong pinning metal/carbon fiber composite material joint comprises the following steps:

Step 1, selecting plates: selecting the required metal plates and carbon fiber composite plates, and processing the metal plates and carbon fiber composite plates into the actual required shapes and sizes;

In this embodiment, a 5052 aluminum alloy plate with a length of 60 mm, a width of 20 mm, and a thickness of 1 mm and a short-cut carbon fiber reinforced nylon plate (SCF-PA) of the same size are selected, that is, the metal plate in this embodiment is a 5052 aluminum alloy plate, and the carbon fiber composite material plate is a short-cut carbon fiber reinforced nylon plate.

Step 2, plate surface treatment: use anhydrous ethanol to remove oil stains and oxide films on the surface of metal plates and carbon fiber composite plates;

Step 3, laser processing of the metal plate surface: using a nanosecond laser processing system to perform laser drilling on the surface-treated metal plate to produce a micron-level porous structure;

The parameters of the nanosecond laser processing system are set as follows: speed of 200 mm/s, frequency of 25 kHz, power of 75 W, and the processed micron-scale porous structure is cylindrical, with a width or diameter of 300 μm and a depth of 200 μm.

Step 4: Silane coupling agent modification of the metal plate surface: Silane coupling agent is attached to the surface of the metal plate after laser processing, and high-temperature modification treatment is performed. The specific steps are as follows:

The metal plate is completely soaked with clean water to produce a seamless water film, and then immediately immersed in the silane coupling agent for 1 to 2 minutes; after taking out the metal plate, the surface water film is dried, placed in a box-type heating furnace, and then maintained at a high temperature of 120°C for 20 minutes to complete the silane coupling agent modification of the metal plate surface. The silane coupling agent in this embodiment is KH-550 type silane coupling agent.

Step 5, microcapsule preparation: adding a polymer resin material to a solvent, stirring evenly, and then adding an emulsifier to form a uniform encapsulation liquid, then immersing the chopped fiber bundle in the encapsulation liquid, cooling and solidifying with liquid nitrogen, separating the solvent, and drying to obtain a resin-based microcapsule encapsulating the chopped fiber bundle;

The polymer resin material of this embodiment is nylon, the solvent is formic acid, and the emulsifier is a phospholipid emulsifier with a mass fraction of 1%. The weight percentages of nylon, chopped fiber bundles, formic acid and phospholipid emulsifier are 40%:10%:20%:30%, and the resin-based microcapsules that embed the chopped fiber bundles are spherical microcapsules with a diameter of 80~120μm.

Step 6, microcapsule embedding: embedding the resin-based microcapsules encapsulating the chopped fiber bundles into the micron-scale porous structure on the modified metal plate;

Step 7, ultrasonic welding: the surface treated carbon fiber composite material plate and the metal plate with embedded microcapsules are stacked and fixed in a single-side overlap manner to be connected, and ultrasonic welding is performed;

The ultrasonic welding of this embodiment is performed on an ultrasonic welding device, and the parameters of the ultrasonic welding device are set as follows: rated power of 4 kW, rated frequency of 20 kHz, maximum welding amplitude of 52 μm, welding time of 2500 ms, and welding pressure of 0.3 MPa. The actual energy consumption range of ultrasonic welding of this embodiment is 600-1000 J.

Step 8: Cool the finished product.

The metal/carbon fiber composite material joint prepared in Example 1 was observed for its microstructure, and the results are shown in Figures 1 to 3, wherein Figure 1 is a microscopic morphology of the connection interface of the metal/carbon fiber composite material joint, Figure 2 is a morphology of the micron-scale porous structure obtained by laser processing, Figure 3 is a three-dimensional contour morphology of the micron-scale porous structure obtained by laser processing, and Figure 4 is a microscopic morphology of the connection interface of the metal/carbon fiber composite material joint without embedded microcapsules.

The single-sided lapped metal/carbon fiber composite material joint obtained in this embodiment has a good morphology. It is observed that at the connection interface, the high-temperature melted microcapsules release a large number of chopped carbon fiber bundles, which fully fill the micron-level porous structure on the surface of the metal plate, forming a significant pinning effect; the melted resin of the carbon fiber composite plate is filled into the micron-level porous structure on the surface of the metal plate under the action of pressure, and melts with the melted resin film of the microcapsules, and the melted microcapsules are squeezed into close contact with the metal plate, which helps the resin to wet and spread on the surface of the metal plate; with the help of favorable conditions such as high temperature, pressure and extrusion of the molten resin in the micron-level porous structure, a chemical bonding reaction is formed at the connection interface between the metal plate and the carbon fiber composite material plate, and this chemical bonding reaction is particularly concentrated in the micron-level porous structure; the maximum tensile shear force of the metal/carbon fiber composite joint tested by the Instron 5900 electronic universal testing machine is 1997.86N. When the traditional ultrasonic welding method is used under the same surface treatment conditions, the maximum tensile shear force of the metal/carbon fiber composite joint is 144.36N.

Example 2

A method for preparing a microcapsule strong pinning metal/carbon fiber composite material joint comprises the following steps:

Step 1, selecting plates: selecting the required metal plates and carbon fiber composite plates, and processing the metal plates and carbon fiber composite plates into the actual required shapes and sizes;

In this embodiment, an AZ318 magnesium alloy plate with a length of 60 mm, a width of 20 mm, and a thickness of 1 mm and a short-cut carbon fiber reinforced nylon plate (SCF-PA) of the same size are selected, that is, the metal plate in this embodiment is an AZ318 magnesium alloy plate, and the carbon fiber composite material plate is a short-cut carbon fiber reinforced nylon plate.

Step 2, plate surface treatment: use anhydrous ethanol to remove oil stains and oxide films on the surface of metal plates and carbon fiber composite plates;

Step 3, laser processing of the metal plate surface: using a nanosecond laser processing system to perform laser drilling on the surface-treated metal plate to produce a micron-level porous structure;

The parameters of the nanosecond laser processing system are set as follows: speed of 300 mm/s, frequency of 25 kHz, power of 110 W, and the processed micron-scale porous structure is cylindrical, with a width or diameter of 350 μm and a depth of 500 μm.

Step 4: Silane coupling agent modification of the metal plate surface: Silane coupling agent is attached to the surface of the metal plate after laser processing, and high-temperature modification treatment is performed. The specific steps are as follows:

The metal plate is completely soaked with clean water to produce a seamless water film, and then immediately immersed in the silane coupling agent for 1 to 2 minutes; after taking out the metal plate, the surface water film is dried, placed in a box-type heating furnace, and then maintained at a high temperature of 120°C for 20 minutes to complete the silane coupling agent modification of the metal plate surface. The silane coupling agent in this embodiment is KH-550 type silane coupling agent.

Step 5, microcapsule preparation: adding a polymer resin material to a solvent, stirring evenly, and then adding an emulsifier to form a uniform encapsulation liquid, then immersing the chopped fiber bundle in the encapsulation liquid, cooling and solidifying with liquid nitrogen, separating the solvent, and drying to obtain a resin-based microcapsule encapsulating the chopped fiber bundle;

The polymer resin material of this embodiment is nylon, the solvent is formic acid, and the emulsifier is a phospholipid emulsifier with a mass fraction of 1%. The weight percentages of nylon, chopped fiber bundles, formic acid and phospholipid emulsifier are 40%:10%:20%:30%, and the resin-based microcapsules that embed the chopped fiber bundles are spherical microcapsules with a diameter of 80~120μm.

Step 6, microcapsule embedding: embedding the resin-based microcapsules encapsulating the chopped fiber bundles into the micron-scale porous structure on the modified metal plate;

Step 7, ultrasonic welding: the surface treated carbon fiber composite material plate and the metal plate with embedded microcapsules are stacked and fixed in a single-side overlap manner to be connected, and ultrasonic welding is performed;

The ultrasonic welding of this embodiment is performed on an ultrasonic welding device, and the parameters of the ultrasonic welding device are set as follows: rated power of 4 kW, rated frequency of 20 kHz, maximum welding amplitude of 52 μm, welding time of 3000 ms, and welding pressure of 0.4 MPa. The actual energy consumption range of ultrasonic welding of this embodiment is 1000-1500 J.

Step 8: Cool the finished product.

The single-sided overlapped metal/carbon fiber composite material joint obtained in this embodiment has a good morphology. It is observed that the molten resin and the chopped carbon fiber bundles fill the micron-level porous structure on the surface of the metal plate at the connection part, forming a significant pinning effect, which improves its bonding strength; the maximum tensile shear force of the metal/carbon fiber composite material joint tested by the Instron 5900 electronic universal testing machine is 1020.93N. When the traditional ultrasonic welding method is used under the same surface treatment conditions, the maximum tensile shear force of the metal/carbon fiber composite material joint is 123.78N.

Example 3

A method for preparing a microcapsule strong pinning metal/carbon fiber composite material joint comprises the following steps:

Step 1, selecting plates: selecting the required metal plates and carbon fiber composite plates, and processing the metal plates and carbon fiber composite plates into the actual required shapes and sizes;

In this embodiment, a SS304 stainless steel plate with a length of 60 mm, a width of 20 mm, and a thickness of 1 mm and a short-cut carbon fiber reinforced polyetheretherketone plate (SCF-PEEK) of the same size are selected, that is, the metal plate in this embodiment is a SS304 stainless steel plate, and the carbon fiber composite material plate is a short-cut carbon fiber reinforced polyetheretherketone plate.

Step 2, plate surface treatment: use anhydrous ethanol to remove oil stains and oxide films on the surface of metal plates and carbon fiber composite plates;

Step 3, laser processing of the metal plate surface: using a nanosecond laser processing system to perform laser drilling on the surface-treated metal plate to produce a micron-level porous structure;

The parameters of the nanosecond laser processing system are set as follows: speed of 500 mm/s, frequency of 25 kHz, power of 155 W, and the processed micron-scale porous structure is cylindrical, with a width or diameter of 400 μm and a depth of 600 μm.

Step 4: Silane coupling agent modification of the metal plate surface: Silane coupling agent is attached to the surface of the metal plate after laser processing, and high-temperature modification treatment is performed. The specific steps are as follows:

The metal plate is completely soaked with clean water to produce a seamless water film, and then immediately immersed in the silane coupling agent for 1 to 2 minutes; after taking out the metal plate, the surface water film is dried, placed in a box-type heating furnace, and then maintained at a high temperature of 120°C for 20 minutes to complete the silane coupling agent modification of the metal plate surface. The silane coupling agent in this embodiment is KH-550 type silane coupling agent.

Step 5, microcapsule preparation: adding a polymer resin material to a solvent, stirring evenly, and then adding an emulsifier to form a uniform encapsulation liquid, then immersing the chopped fiber bundle in the encapsulation liquid, cooling and solidifying with liquid nitrogen, separating the solvent, and drying to obtain a resin-based microcapsule encapsulating the chopped fiber bundle;

The polymer resin material of this embodiment is polyetheretherketone, the solvent is dichloromethane, and the emulsifier is a polyvinyl alcohol emulsifier with a mass fraction of 5%. The weight percentages of the polyetheretherketone, the chopped fiber bundles, dichloromethane and the polyvinyl alcohol emulsifier are 40%:5%:25%:30%, and the resin-based microcapsules that embed the chopped fiber bundles are spherical microcapsules with a diameter of 120~150μm.

Step 6, microcapsule embedding: embedding the resin-based microcapsules encapsulating the chopped fiber bundles into the micron-scale porous structure on the modified metal plate;

Step 7, ultrasonic welding: the surface treated carbon fiber composite material plate and the metal plate with embedded microcapsules are stacked and fixed in a single-side overlap manner to be connected, and ultrasonic welding is performed;

The ultrasonic welding of this embodiment is performed on an ultrasonic welding device, and the parameters of the ultrasonic welding device are set as follows: rated power of 4 kW, rated frequency of 20 kHz, maximum welding amplitude of 52 μm, welding time of 4000 ms, and welding pressure of 0.6 MPa. The actual energy consumption of ultrasonic welding of this embodiment can reach up to 2000 J.

Step 8: Cool the finished product.

The single-sided overlapped metal/carbon fiber composite material joint obtained in this embodiment has a good morphology. It is observed that the molten resin and the chopped carbon fiber bundles fill the micron-level porous structure on the surface of the metal plate at the connection part, forming a significant pinning effect, which improves its bonding strength; the maximum tensile shear force of the metal/carbon fiber composite material joint tested by the Instron 5900 electronic universal testing machine is 983.57N. When the traditional ultrasonic welding method is used under the same surface treatment conditions, the maximum tensile shear force of the metal/carbon fiber composite material joint is 110.12N.

Comparative Example 1

The ultrasonic enhanced connection method of aluminum alloy/SCF-PA is as follows:

Step 1, selection of experimental plates: select 5052 aluminum alloy plates with a length of 60 mm, a width of 20 mm, and a thickness of 1 mm, and short-cut carbon fiber reinforced nylon plates (SCF-PA) of the same size.

Step 2, plate surface treatment: scrub the aluminum plate and SCF-PA plate with anhydrous ethanol cleaning solution.

Step 3, electrolytic processing of aluminum plate surface: The electrolytic processing technology adopts constant current processing, the current is 5A, the electrolyte is selected as 2mol/LNaOH solution, and the depth of small hole processing is controlled by the duration of electrolytic processing. A 6*6 micron-level porous, inclined cylindrical lattice structure is processed, the micron structure has a diameter of 300μm, a depth of 500μm, a spacing of 200μm, and an inclination angle of 60°.

Step 4: Silane coupling agent treatment on the surface of the aluminum plate: completely soak the aluminum plate with clean water to produce a seamless water film, and immediately immerse it in the silane treatment agent to enhance the bonding effect.

Step 5, ultrasonic welding: The SCF-PA plate from which the surface oil has been removed is combined with the portion to be connected of the aluminum plate obtained by electrolytic processing in a single-side overlap manner, and ultrasonic welding is performed. The rated power of the ultrasonic equipment is 4kW, the rated frequency is 20kHz, the welding time is 2500ms, the maximum welding amplitude is 52μm, and the welding pressure is 0.3MPa. The actual energy consumption of ultrasonic welding in this embodiment is about 1000J.

Step 6: Cool the finished product.

This embodiment uses electrolytic processing on the metal surface to process a micron-scale porous and inclined cylindrical lattice structure, and uses the effect of the ultrasonic energy field to squeeze the molten resin and chopped carbon fiber bundles into the metal surface, which can promote the close bonding of the metal/carbon fiber composite material. However, the prepared interface area has the problem of damage to the carbon fiber composite material. The maximum tensile shear force of the metal/carbon fiber composite joint tested by the Instron 5900 electronic universal testing machine is 1087.64N. Example 1 of the present invention adopts the method of "metal surface laser processing microstructure + silane coupling agent pretreatment + microcapsule implantation" to embed the resin-based microcapsules embedded with chopped fiber bundles into the micron-scale porous structure on the surface of the metal plate, melt the microcapsules during ultrasonic welding, release the chopped carbon fiber bundles in the microcapsules, and make the molten resin and chopped carbon fiber bundles tightly adsorbed on the surface of the metal plate. The present invention uses laser processing to produce a micron-level porous structure. Compared with electrolytic processing, it has higher precision, is conducive to the embedding of microcapsules of specific sizes, and further enhances the close contact between the resin, carbon fiber bundles and metal. The prepared bonding interface is tighter, the bonding strength is higher, and the morphology is better. In terms of connection strength, using the same material, the maximum tensile shear force obtained by the method of the present invention increases by 910.22N.

In summary: The present invention adopts a microcapsule-assisted metal/carbon fiber composite material strong pinning ultrasonic welding method, which can realize the preparation of high-strength structural parts of different metal materials (aluminum alloy, magnesium alloy, stainless steel, etc.) and carbon fiber composite materials (SCF-PA, SCF-PEEK, etc.), and its experimental data are shown in Table 1.

Table 1 Experimental data of metal/carbon fiber composite material joints in the embodiment

The above shows and describes the main features and advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the present invention.

In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims (10)

1. A method for preparing a microcapsule strong pinning metal/carbon fiber composite material joint, characterized in that it comprises the following steps: Step 1, selecting plates: selecting the required metal plates and carbon fiber composite plates, and processing the metal plates and carbon fiber composite plates into the actual required shapes and sizes; Step 2, plate surface treatment: removing oil stains and oxide films on the surface of metal plates and carbon fiber composite plates; Step 3, laser processing of the metal plate surface: performing laser drilling on the surface-treated metal plate to produce a micron-level porous structure; Step 4, silane coupling agent modification of the metal plate surface: a silane coupling agent is attached to the surface of the metal plate after laser processing, and a high-temperature modification treatment is performed; Step 5, microcapsule preparation: adding a polymer resin material to a solvent, stirring evenly, and then adding an emulsifier to form a uniform encapsulation liquid, then immersing the chopped fiber bundle in the encapsulation liquid, cooling and solidifying with liquid nitrogen, separating the solvent, and drying to obtain a resin-based microcapsule encapsulating the chopped fiber bundle; Step 6, microcapsule embedding: embedding the resin-based microcapsules encapsulating the chopped fiber bundles into the micron-scale porous structure on the modified metal plate; Step 7, ultrasonic welding: the surface treated carbon fiber composite material plate and the metal plate with embedded microcapsules are stacked and fixed in a single-side overlap manner to be connected, and ultrasonic welding is performed; Step 8: Cool the finished product. 2. The method for preparing a microcapsule strongly pinned metal/carbon fiber composite material joint according to claim 1 is characterized in that the material of the metal plate in step 1 is aluminum alloy, magnesium alloy or stainless steel. 3. The method for preparing a microcapsule strongly pinned metal/carbon fiber composite material joint according to claim 1 is characterized in that anhydrous ethanol is used for the surface treatment of the plate in step 2. 4. According to the method for preparing a microcapsule strongly pinned metal/carbon fiber composite material joint according to claim 1, it is characterized in that the laser processing of the metal plate surface in step 3 adopts a nanosecond laser processing system, and the parameters of the nanosecond laser processing system are set as: speed is 200-500 mm/s, frequency is 25 kHz, and power is 75-155 W. 5. A method for preparing a microcapsule strongly pinned metal/carbon fiber composite material joint according to claim 1 or 4, characterized in that the width or diameter of the micron-scale porous structure in step 3 is 300-400 μm, and the depth is 200-600 μm. 6. The method for preparing a microcapsule strong pinning metal/carbon fiber composite material joint according to claim 1, characterized in that the specific steps of modifying the metal plate surface with a silane coupling agent in step 4 are: The metal plate is completely soaked with clean water to produce a seamless water film, and then immediately immersed in the silane coupling agent for 1 to 2 minutes; after the metal plate is taken out, the surface water film is dried, and then maintained at a high temperature of 120°C for 20 minutes to complete the silane coupling agent modification of the metal plate surface. 7. A method for preparing a microcapsule strong pinning metal/carbon fiber composite material joint according to claim 1 or 6, characterized in that the silane coupling agent in step 4 is a KH-550 silane coupling agent. 8. A method for preparing a microcapsule strong pinning metal/carbon fiber composite material joint according to claim 1, characterized in that the polymer resin material in step 5 is nylon or polyetheretherketone. When the polymer resin material is nylon, formic acid is selected as the solvent, and the emulsifier is selected as a phospholipid emulsifier with a mass fraction of 1%, and the weight percentage of nylon, chopped fiber bundles, formic acid and phospholipid emulsifier is 40%:10%:20%:30%; when the polymer resin material is polyetheretherketone, dichloromethane is selected as the solvent, and a polyvinyl alcohol emulsifier with a mass fraction of 5% is selected as the emulsifier, and the weight percentage of polyetheretherketone, chopped fiber bundles, dichloromethane and polyvinyl alcohol emulsifier is 40%:5%:25%:30%. 9. A method for preparing a microcapsule strongly pinned metal/carbon fiber composite material joint according to claim 1 or 8, characterized in that the resin-based microcapsules that embed the chopped fiber bundles in step 5 are spherical microcapsules with a diameter of 80-150 μm. 10. The method for preparing a microcapsule strongly pinned metal/carbon fiber composite material joint according to claim 1 is characterized in that the ultrasonic welding in step 7 is performed on an ultrasonic welding device, and the parameters of the ultrasonic welding device are set as follows: rated power of 4 kW, rated frequency of 20 kHz, maximum welding amplitude of 52 μm, welding time of 2500~4000 ms, and welding pressure of 0.3~0.6 MPa.