Preparation method of CNT composite material energy-conducting rib, CNT composite material energy-conducting rib and method for preparing high-interface-strength welding joint by using CNT composite material energy-conducting rib

Abstract

The invention discloses a preparation method of a CNT composite material energy-conducting rib, the CNT composite material energy-conducting rib and a method for preparing a high-interface-strength welding joint by using the CNT composite material energy-conducting rib. A thermoplastic material is used as a matrix, a resin film of a carbon nanotube is added into the matrix, and a thermoplastic resin-based composite material laminated plate to be welded is pretreated; the to-be-welded areas of the two pretreated thermoplastic resin matrix composite laminated plates are in lap joint, and a lap joint is formed; the CNT composite material energy-conducting rib is placed in a lap joint contact face, and a to-be-machined weldment is obtained; ultrasonic vibration is placed on a to-be-machined welding part, pressure maintaining is carried out after ultrasonic vibration is finished, and the thermoplastic resin matrix composite material welding joint is obtained after cooling. The carbon nanotubes are added into the energy guider, and the strength of a welded joint is improved by utilizing relatively good electrical conductivity, thermal conductivity and rigidity of the carbon nanotubes. And the interface strength of the joint is improved by adding the carbon nano tubes into the thermoplastic energy-conducting ribs, so that high-quality welding joint strength is formed.

Description

Technical Field

[0001] The invention discloses a material connection technology field, and in particular, a method for preparing CNT composite material energy conductors, CNT composite material energy conductors, and a method for preparing high interface strength welding joints using the same. Background Art

[0002] Ultrasonic welding technology is gaining more and more attention in modern industrial production due to its significant advantages such as fast and efficient, no need for additional adhesives or solvents, small heat-affected zone, molecular-level bonding, environmental friendliness, strong adaptability, easy automation, no need for preheating materials, and stability and durability of welded joints. This technology is particularly suitable for the integrity, load-bearing capacity, fatigue life and environmental adaptability of composite structures, and plays an important role in reducing manufacturing and maintenance costs, ensuring product safety and promoting the research and development of new materials and new processes. The design of ultrasonic welding joints is the core of composite material connection technology, which directly affects the reliability and economy of products, especially in key areas such as aerospace and automobile manufacturing. Optimized welding joint design helps to simplify maintenance processes, reduce environmental impact, and meet the strict environmental protection requirements of modern manufacturing, improve production efficiency and ensure the excellent performance of welded structures. Ultrasonic welding, as a green and efficient welding method, is widely used in the connection of carbon fiber reinforced thermoplastic composites, in which the design of welding joints is crucial to welding quality. Ultrasonic welding is particularly suitable for welding thermoplastic materials. It heats the thermoplastic resin at the welding interface to a molten state, allowing the molecular chains to move freely and cross-link with the molecular chains on the other side through the interface to achieve complete healing, thereby completing the welding process.

[0003] Ultrasonic welding is a technology that uses high-frequency vibration waves of 20kHz to 40kHz to connect materials. The electrical energy is converted into mechanical vibrations through a transducer and transmitted to the surface of the material to be welded, so that the material in the contact area generates heat and melts under the action of pressure and friction. In the molten state, the molecular chains of the material move freely, diffuse and entangle between the two contact surfaces to form new molecular bonds. Energy directors (EDs) are usually used in the welding process to concentrate and transfer the heat generated by ultrasound to improve melting efficiency. When the ultrasonic vibration stops and maintains a certain pressure, the molten material solidifies during the cooling process to form a strong connection. This technology is particularly suitable for the connection of thermoplastic composites because it is fast, efficient, environmentally friendly and does not damage the reinforcing fibers.

[0004] The heat source of ultrasonic welding mainly comes from two aspects: interface friction and viscoelastic friction. In the early stage of welding, the interface friction generates a lot of heat due to the friction between the workpieces driven by the ultrasonic vibration energy, which is the initial heat source in the welding process. As the resin temperature in the welding area reaches the glass transition temperature (Tg), the viscoelastic friction begins to dominate. When the material is subjected to periodic sinusoidal alternating force, the friction between the molecules is converted into internal energy, generating a large amount of heat energy. The two heat sources work together to enable the contact surface of the thermoplastic material to melt quickly, forming a strong fusion between the molecular chains, achieving efficient and concentrated heat input, and facilitating the formation of high-quality welded joints. The energy director is crucial in ultrasonic welding. Its main function is to concentrate the viscoelastic friction energy generated by ultrasonic welding at the contact interface to promote the rapid melting and flow of the resin, thereby wetting the surface of the connected parts, enhancing the molecular diffusion and entanglement between the interfaces, and forming a stable connection. The energy director helps to improve the quality of the welded joint, reduce damage to the parent material, control the size and shape of the welded area, and adapt to the welding needs of complex shapes, ensuring the controllability and repeatability of the welding process.

[0005] By using energy directors (energy directors), it is possible to ensure that the resin in the welding area is fully melted and evenly distributed, reduce welding defects, and improve welding efficiency and joint stability. Therefore, it is very meaningful to develop an energy director. Summary of the invention

[0006] In view of this, the present invention provides a method for preparing CNT composite energy conductors, CNT composite energy conductors and a method for preparing high interface strength welding joints using the same, so as to improve the interface strength of ultrasonic welding joints.

[0007] The present invention includes the following technical solutions:

[0008] In one aspect, the present invention provides a method for preparing a CNT composite material energy conductor, comprising:

[0009] Processing carbon nanotubes: physically grinding carbon nanotubes to obtain granular carbon nanotube particles;

[0010] A thermoplastic material solution is prepared, and when the thermoplastic material solution begins to change from a fluid state to a viscous fluid state, the ground carbon nanotubes are added thereto and stirred continuously to obtain a uniformly mixed solution, and the uniformly mixed solution is subjected to ultrasonic treatment to obtain a thermoplastic material solution with carbon nanotubes added thereto;

[0011] Then pour the thermoplastic material solution with carbon nanotubes added onto the aluminum alloy sheet, and then spread the solution evenly with a film-laying brush;

[0012] Then put it into a vacuum oven and dry it. After the vacuum oven cools down to room temperature, take it out and peel off the thermoplastic material film from the aluminum alloy sheet to obtain the CNT composite material energy-conducting ribs.

[0013] Preferably, a thermoplastic material is used as a matrix, and a resin film with carbon nanotubes is added to the matrix, wherein the thermoplastic material is one or a mixture of polycarbonate (PC), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyetherimide (PEI), polyetherketoneketone (PEKK), and polyetherketone (PEK).

[0014] Preferably, the CNT composite material energy conductor has a thickness of 0.1 mm to 0.4 mm.

[0015] On the other hand, the present invention also provides a method for preparing a composite material welding joint using the CNT composite material energy conductor, comprising:

[0016] Pre-treating thermoplastic resin-based composite laminates to be welded;

[0017] overlapping the areas to be welded of two pretreated thermoplastic resin-based composite laminates to form a lap joint;

[0018] Placing the CNT composite material energy conductor in the contact surface of the lap joint to obtain a weldment to be processed;

[0019] Ultrasonic vibration is placed on the workpiece to be welded, and ultrasonic vibration is applied to the welding area for welding. After the ultrasonic vibration ends, pressure is maintained, and after cooling, a thermoplastic resin-based composite material welding joint is obtained.

[0020] Preferably, the welding is performed by applying ultrasonic vibration to the area to be welded: the vibration frequency is 15 kHz, the vibration amplitude is 15-30 μm, the welding pressure is 0.2-0.6 MPa, and the ultrasonic time is 1-10 s.

[0021] Preferably, the thermoplastic resin-based composite material laminates to be welded are pretreated: the two thermoplastic resin-based composite material laminates to be welded are cleaned to remove surface impurities.

[0022] The present invention provides a method for preparing CNT composite energy conductors, CNT composite energy conductors and a method for preparing high interface strength welded joints using the same, wherein carbon nanotubes are added to the energy director to improve the strength of the welded joint by using the relatively good electrical conductivity, thermal conductivity and rigidity thereof. Furthermore, carbon nanotubes are added to the thermoplastic energy conductors to improve the interface strength of the joint, thereby forming a high-quality welded joint strength.

[0023] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 The ultrasonic welding process schematic diagram provided for the disclosed implementation of the present invention is as follows: 1-ultrasonic vibration head; 2-thermoplastic composite material plate; 3-energy director;

[0027] Figure 2 Schematic diagram of the process of preparing the PEI solution provided in the embodiment disclosed in the present invention: 1-N,N-dimethylacetamide solution; 12-PEI particles; 13-carbon nanotubes;

[0028] Figure 3 A schematic diagram of the ultrasonic treatment process of a PEI solution provided in an embodiment disclosed in the present invention.

[0029] Figure 4 A schematic diagram of preparing energy conducting ribs containing carbon nanotubes by tape casting is provided as an example of the disclosed implementation of the present invention. DETAILED DESCRIPTION

[0030] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of methods consistent with some aspects of the present invention as detailed in the appended claims.

[0031] In order to improve the interface strength of the ultrasonic welded joint of the thermoplastic resin-based composite material, firstly, this embodiment provides a method for preparing CNT composite energy conductor ribs, comprising:

[0032] Processing carbon nanotubes: physically grinding carbon nanotubes to obtain granular carbon nanotube particles;

[0033] A thermoplastic material solution is prepared, and when the thermoplastic material solution begins to change from a fluid state to a viscous fluid state, the ground carbon nanotubes are added thereto and stirred continuously to obtain a uniformly mixed solution, and the uniformly mixed solution is subjected to ultrasonic treatment to obtain a thermoplastic material solution with carbon nanotubes added thereto;

[0034] Then pour the thermoplastic material solution with carbon nanotubes added onto the aluminum alloy sheet, and then spread the solution evenly with a film-laying brush;

[0035] Then put it into a vacuum oven and dry it. After the vacuum oven cools down to room temperature, take it out and peel off the thermoplastic material film from the aluminum alloy sheet to obtain the CNT composite material energy-conducting ribs.

[0036] Preferably, the method for making CNT composite energy conductors is as follows: for the treatment of carbon nanotubes, an appropriate amount of carbon nanotubes is measured and placed in a grinding mortar for physical grinding until there are no large particles and then set aside. For the preparation of PEI solution, 450 ml of N, N-dimethylacetamide solution is weighed and poured into a three-necked flask in an oil bath, and the temperature of the oil bath is set to 140°C; then 150 g of PEI particles are poured into the three-necked flask with the help of a funnel, and stirring is started at the same time; when the temperature of the oil bath reaches 140°C, the timing is started, and the three-necked flask is taken out after four hours. During this process, when the prepared PEI solution begins to change from a flowing state to a viscous flow state, an appropriate amount of ground carbon nanotubes is added and stirring is continued until the end of 4 hours. Then, ultrasonic treatment is performed under the conditions of an ultrasonic power of 325 Hz and an ultrasonic time of 90 min. Then pour the PEI solution with carbon nanotubes onto a 200mm×200mm aluminum alloy sheet, and then use a film-laying brush to spread the PEI solution flat; then put it into a vacuum oven and let it stand at 90°C for 6 hours. After the vacuum oven cools down to room temperature, take it out and use a scalpel to peel off the PEI film from the aluminum alloy sheet to obtain a new energy director and energy ribs.

[0037] In a second aspect, the present embodiment also provides that the energy conducting ribs are made of a resin-based composite material resin to form a 0.1mm-0.4mm resin film (generally 0.2mm).

[0038] The material used for the energy director (also called energy guiding rib) is a thermoplastic composite material. More preferably, the material used for the energy director is one of thermoplastic polymer materials such as polyetheretherketone (PEEK) or polyetherimide (PEI).

[0039] The energy director is made by tape casting. The thickness of the new energy director made by tape casting is 0.1mm-0.4mm resin film (usually 0.2mm).

[0040] In a third aspect, the present embodiment provides a method for preparing a composite material welding joint using the CNT composite material energy conductor, comprising: step 1: pretreating two thermoplastic resin-based composite material laminates to be welded to remove impurities on their surfaces; wherein the cleaning agent used for cleaning is preferably acetone (CH 3 COCH 3 ).

[0041] Specifically, two thermoplastic resin-based composite material laminates to be welded are cleaned to remove surface impurities.

[0042] Step 2: Overlap the areas to be welded of two treated thermoplastic resin-based composite materials (here carbon fiber / polyetheretherketone composite materials) to form a lap joint, and place the prepared energy guiding ribs on the contact surface of the lap joint (placed between two carbon fiber / polyetheretherketone composite materials plates) to obtain the weldment to be processed; place ultrasonic vibration on the weldment to be processed, apply ultrasonic vibration to the welding area for welding, maintain pressure after the ultrasonic vibration ends, and obtain the carbon fiber / polyetheretherketone composite material welded joint after cooling.

[0043] In step 2, ultrasonic vibration is applied for welding, wherein the vibration frequency is 15kHz, the vibration amplitude is 15-30μm, the welding pressure is 0.2-0.6MPa, and the ultrasonic time is 1-10s. Ultrasonic welding has the characteristics of short cycle, high efficiency, easy automation and suitability for mass production. And no special circulation method is required to remove smoke and cool down. And the efficiency of ultrasonic welding technology makes it have higher yield and higher cost compared with other connection technologies.

[0044] Taking carbon fiber / polyetheretherketone composite laminates as an example, a method for adding carbon nanotubes in the preparation of energy guiding ribs to improve the strength of carbon fiber / polyetheretherketone composite ultrasonic welded joints has a single lap welded joint shear strength (LSS) of 30-50MPa.

[0045] This embodiment provides an energy director in the form of a PEEK resin plus carbon nanotubes, in which the carbon nanotubes form protrusions in the resin film, which play an energy-guiding role, so that during the ultrasonic welding of the carbon fiber / polyetheretherketone composite material, the polyetheretherketone composite material is heated under the combined action of interface friction and intermolecular forces, wherein the heat source during the ultrasonic welding of the carbon fiber / polyetheretherketone composite material mainly comes from friction heat and viscoelastic heat. In the initial stage of welding, interface friction mainly occurs, and after the temperature rises to the glass transition temperature of the resin, viscoelasticity mainly occupies a major position. When the temperature reaches the glass transition temperature (Tg), the thermoplastic composite material is mainly heated by the viscoelastic material, and the viscoelastic heat provides the most needed heat during the welding process; when the temperature is lower than Tg, the thermoplastic composite material obtains heat energy through interface friction, thereby increasing the temperature of the welding zone. The mechanism of action of adding CNTs to energy guiding ribs is mainly manifested in the following three synergistic effects: first, CNTs significantly improve the mechanical properties of energy guiding ribs through their ultra-high stiffness and strength, optimize the efficiency of vibration energy transfer, and reduce energy loss; second, the high thermal conductivity of CNTs can quickly disperse the heat of the welding interface, avoid local overheating and promote uniform melting of the material, while accelerating the welding process through friction-assisted heat generation; in addition, CNTs are embedded in the matrix at the molten interface to form a nano-scale reinforced network, which strengthens the mechanical interlocking effect and reduces micropores and crack defects, thereby improving the overall strength and density of the welded joint. These characteristics jointly optimize the welding quality and process efficiency.

[0046] The present invention is further explained below in conjunction with specific embodiments, but is not intended to limit the protection scope of the present invention.

[0047] Example 1

[0048] Carbon nanotubes are added into polyimide powder, and an energy-conducting fascia containing carbon nanotubes is prepared by a tape casting method, thereby obtaining a new type of director with a carbon nanotube content of 0.02wt%.

[0049] The obtained new energy director is placed in the lap welding area of ​​the carbon fiber reinforced polyetheretherketone (CF / PEEK) thermoplastic composite material to obtain a welded part to be processed, and the welded part to be processed is placed in a welding fixture, and an ultrasonic vibration head applies ultrasonic vibration on the upper side of the welded area; during the welding process, the ultrasonic vibration head applies a vibration frequency of 15kHz, an amplitude of 24μm, a welding pressure of 0.4MPa, an ultrasonic time of 3s, and a holding time of 10s; after cooling, a CF / PEEK thermoplastic resin-based composite ultrasonic welding joint is obtained, and its LSS value reaches 41.4MPa.

[0050] Example 2

[0051] Carbon nanotubes are added into polyimide powder, and an energy-conducting fascia containing carbon nanotubes is prepared by a tape casting method, thereby obtaining a new type of director with a carbon nanotube content of 0.04wt%.

[0052] The obtained new energy director is placed in the lap welding area of ​​the carbon fiber reinforced polyetheretherketone (CF / PEEK) thermoplastic composite material to obtain a welded part to be processed, and the welded part to be processed is placed in a welding fixture, and an ultrasonic vibration head applies ultrasonic vibration on the upper side of the welded area; during the welding process, the ultrasonic vibration head applies a vibration frequency of 15kHz, an amplitude of 24μm, a welding pressure of 0.4MPa, an ultrasonic time of 3s, and a holding time of 10s; after cooling, a CF / PEEK thermoplastic resin-based composite ultrasonic welding joint is obtained, and its LSS value reaches 43.8MPa.

[0053] Example 3

[0054] Carbon nanotubes are added to polyimide powder, and an energy-conducting fascia containing carbon nanotubes is prepared by a tape casting method, thereby obtaining a new type of director with a carbon nanotube content of 0.06wt%.

[0055] The obtained new energy director is placed in the lap welding area of ​​the carbon fiber reinforced polyetheretherketone (CF / PEEK) thermoplastic composite material to obtain a welded part to be processed, and the welded part to be processed is placed in a welding fixture, and an ultrasonic vibration head applies ultrasonic vibration on the upper side of the welded area; during the welding process, the ultrasonic vibration head applies a vibration frequency of 15kHz, an amplitude of 24μm, a welding pressure of 0.4MPa, an ultrasonic time of 3s, and a holding time of 10s; after cooling, a CF / PEEK thermoplastic resin-based composite ultrasonic welding joint is obtained, and its LSS value reaches 44.1MPa.

[0056] Example 4

[0057] Carbon nanotubes are added into polyimide powder, and an energy-conducting fascia containing carbon nanotubes is prepared by a tape casting method, thereby obtaining a new type of director with a carbon nanotube content of 0.08wt%.

[0058] The obtained new energy director is placed in the lap welding area of ​​the carbon fiber reinforced polyetheretherketone (CF / PEEK) thermoplastic composite material to obtain a welded part to be processed, and the welded part to be processed is placed in a welding fixture, and an ultrasonic vibration head applies ultrasonic vibration on the upper side of the welded area; during the welding process, the ultrasonic vibration head applies a vibration frequency of 15kHz, an amplitude of 24μm, a welding pressure of 0.4MPa, an ultrasonic time of 3s, and a holding time of 10s; after cooling, a CF / PEEK thermoplastic resin-based composite ultrasonic welding joint is obtained, and its LSS value reaches 45.2MPa.

[0059] Example 5

[0060] Carbon nanotubes are added into polyimide powder, and an energy-conducting fascia containing carbon nanotubes is prepared by a tape casting method, thereby obtaining a new type of director with a carbon nanotube content of 0.1wt%.

[0061] The obtained new energy director is placed in the lap welding area of ​​the carbon fiber reinforced polyetheretherketone (CF / PEEK) thermoplastic composite material to obtain a welded part to be processed, and the welded part to be processed is placed in a welding fixture, and an ultrasonic vibration head applies ultrasonic vibration on the upper side of the welded area; during the welding process, the ultrasonic vibration head applies a vibration frequency of 15kHz, an amplitude of 24μm, a welding pressure of 0.4MPa, an ultrasonic time of 3s, and a holding time of 10s; after cooling, a CF / PEEK thermoplastic resin-based composite ultrasonic welding joint is obtained, and its LSS value reaches 47.3MPa.

[0062] In ultrasonic welding, if the concentration of carbon nanotubes (CNTs) in the energy conductors is too high, firstly, the nanotubes will agglomerate and cause uneven dispersion, which will induce stress concentration and weaken the interfacial bonding force, reducing the mechanical properties and energy transfer efficiency of the energy conductors. Secondly, the excessive thermal conductivity of CNTs may cause the heat at the welding interface to dissipate too quickly, resulting in insufficient melting of the material. At the same time, the lubricating effect of high-concentration CNTs may reduce frictional heat generation and prolong the welding time. In addition, excessive CNTs will significantly increase the brittleness of the material and the internal vibration damping, making the energy conductors prone to brittle fracture and hindering the effective transmission of high-frequency ultrasonic energy, further deteriorating the welding quality and process stability.

[0063] Comparative Example 1

[0064] When ultrasonic vibration is applied to the welding area of ​​two carbon fiber / polyetheretherketone composite materials to be welded without placing an energy director, direct welding has a high probability of failure or low interface welding strength.

[0065] Comparative Example 2

[0066] A new energy director with carbon nanotubes added is placed in the lap welding area of ​​the CF-reinforced PEEK thermoplastic resin-based composite material to obtain a welded part to be processed. Ultrasonic vibration is performed on the welding area without applying pressure, and direct welding fails and there is no welding strength.

[0067] Comparative Example 3

[0068] An energy director without carbon nanotubes is placed in the area to be welded of the CF-reinforced PEEK thermoplastic resin-based composite material to obtain a welded part to be processed. The welded part to be processed is placed in a welding fixture. An ultrasonic vibration head applies ultrasonic vibration on the upper side of the area to be welded. During the welding process, the ultrasonic vibration head applies a vibration frequency of 15 kHz, an amplitude of 24 μm, a welding pressure of 0.4 MPa, an ultrasonic time of 3 s, and a holding time of 10 s. After cooling, a CF / PEEK thermoplastic resin-based composite ultrasonic welding head is obtained, and its LSS value is 25.6 MPa.

[0069] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0070] It should be understood that the present invention is not limited to what has been described above and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing CNT composite material energy-conducting ribs, characterized in that: include: Processing carbon nanotubes: physically grinding carbon nanotubes to obtain granular carbon nanotube particles; A thermoplastic material solution is prepared, and when the thermoplastic material solution begins to change from a fluid state to a viscous fluid state, the ground carbon nanotubes are added thereto and stirred continuously to obtain a uniformly mixed solution, and the uniformly mixed solution is subjected to ultrasonic treatment to obtain a thermoplastic material solution with carbon nanotubes added thereto; Then pour the thermoplastic material solution with carbon nanotubes added onto the aluminum alloy sheet, and then spread the solution evenly with a film-laying brush; Then put it into a vacuum oven and dry it. After the vacuum oven cools down to room temperature, take it out and peel off the thermoplastic material film from the aluminum alloy sheet to obtain the CNT composite material energy-conducting ribs.

2. The CNT composite material energy conductor prepared by the method according to claim 1, characterized in that: The resin film is made of a thermoplastic material as a matrix and carbon nanotubes are added into the matrix, wherein the thermoplastic material is one of PEEK and PEI.

3. The CNT composite material energy conductor according to claim 2, characterized in that: The thickness is 0.1mm-0.4mm.

4. A method for preparing a composite material welding joint using the CNT composite material energy conductor according to any one of claims 2 to 3, characterized in that: include: Pre-treating thermoplastic resin-based composite laminates to be welded; overlapping the areas to be welded of two pretreated thermoplastic resin-based composite laminates to form a lap joint; Placing the CNT composite material energy conductor in the contact surface of the lap joint to obtain a weldment to be processed; Ultrasonic vibration is placed on the workpiece to be welded, and ultrasonic vibration is applied to the welding area for welding. After the ultrasonic vibration ends, pressure is maintained, and after cooling, a thermoplastic resin-based composite material welding joint is obtained.

5. The method for preparing a composite material welding joint according to claim 4, characterized in that: The ultrasonic vibration is applied to the welding area for welding: the vibration frequency is 15kHz, the vibration amplitude is 15-30μm, the welding pressure is 0.2-0.6MPa, and the ultrasonic time is 1-10s.

6. The method for preparing a composite material welding joint according to claim 4, characterized in that: Pre-treating the thermoplastic resin-based composite laminates to be welded: cleaning the two thermoplastic resin-based composite laminates to be welded to remove surface impurities.

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