Multi-field coupling driving metallurgical-mechanical interlocking composite connecting method and device

Abstract

This invention relates to the field of metal welding technology, and discloses a multi-field coupling driven metallurgical-mechanical interlocking composite connection method and apparatus. The method includes: processing locking structures on both sides of the welding center of the welding surface of a first metal substrate; placing insulating cloth on the coil of an electromagnetic pulse welding device, placing a second metal substrate on the insulating cloth, and placing pads on both sides of the welding area on the surface of the second metal substrate; then placing the first metal substrate on the pads, and subsequently placing pressure blocks on the first metal substrate; activating the electromagnetic pulse welding device to drive the second metal substrate to collide with the first metal substrate, causing the first and second metal substrates to undergo solid-state metallurgical bonding in the welding area, and filling the locking structures on both sides of the welding area of ​​the second metal substrate to form a mechanical interlock; thereby achieving solid-state metallurgical bonding and mechanical interlocking between metal materials quickly without the need for structural adhesive, improving peel resistance and connection reliability.

Description

Technical Field

[0001] This invention relates to the field of metal welding technology, and in particular to a multi-field coupling driven metallurgical-mechanical interlocking composite connection method and apparatus. Background Technology

[0002] With the urgent need for lightweight structures in fields such as aerospace, new energy vehicles and rail transportation, the application of aluminum alloys, magnesium alloys, high-strength steel and dissimilar metal composite structures is becoming increasingly widespread.

[0003] Electromagnetic pulse welding (MPW), an advanced high-speed solid-state joining technology, utilizes the Lorentz force generated by a high-energy electromagnetic field to drive a workpiece (typically a flyplate) to impact a substrate at high speed within microseconds. At the point of impact, the jet effect generated by the high-speed impact removes the oxide film on the metal surface, bringing the interatomic distance within the bonding range, thus achieving metallurgical bonding. This technology offers significant advantages such as no heat-affected zone, high joint strength, and suitability for joining dissimilar metals.

[0004] However, electromagnetic pulse welding (MPW) typically uses a flat plate lap joint. Limited by the dynamic changes in the coil magnetic field distribution and collision angle, it often only forms an effective metallurgical bond in the central collision region, while a certain width of non-bonded area usually exists on both sides of the joint edge. The existence of this non-bonded area leads to the following main technical problems: 1. Weak peel resistance: Under peel loads, the non-bonded gaps at the joint edges create significant stress concentration, causing cracks to propagate rapidly along the joint interface, resulting in brittle tearing of the joint; 2. Limited connection reliability: Relying solely on the metallurgical bond in the central region, for dissimilar metal connections, if brittle intermetallic compounds form at the interface, the joint is highly susceptible to instantaneous failure under impact loads, lacking safety redundancy.

[0005] To address the aforementioned issues, the preferred solution currently is adhesive-welded composite bonding, which involves applying structural adhesive to the unbonded areas. However, structural adhesives require long curing times, demand extremely high cleanliness of the metal surface, and fail in extremely cold or high temperature environments, limiting the material's service life. Furthermore, insulating structural adhesives hinder the transfer of current and heat, severely impacting the electrical and thermal conductivity of the welded components.

[0006] In view of this, the present invention proposes an all-metal transient composite bonding solution that is free from aging risks, resistant to extreme environments, and requires no curing waiting period, in order to break through the application bottleneck of polymer materials under harsh working conditions. Summary of the Invention

[0007] This invention proposes a multi-field coupling driven metallurgical-mechanical composite connection method and device to overcome the shortcomings of the prior art. This connection method can quickly realize solid-state metallurgical bonding and mechanical interlocking between metal materials without the need for structural adhesive, thereby improving the anti-peeling performance and connection reliability between metal materials.

[0008] The technical solution of this invention is: a multi-field coupling driven metallurgical-mechanical composite connection method for connecting a first metal substrate and a second metal substrate, comprising the following steps: Locking structures are machined on both sides of the welding center of the welding surface of the first metal substrate. The locking structures include through holes, blind holes, or grooves. Deburr and clean the locking structure on the first metal substrate; An insulating cloth is placed on the coil of the electromagnetic pulse welding equipment, a second metal substrate is placed on the insulating cloth, and pads are placed on both sides of the welding area on the surface of the second metal substrate. Then, the locking structure of the first metal substrate is placed on the pads with the locking structure facing down, and the effective magnetic field area of ​​the coil covers the central welding area and the locking structure. Then, a pressure block is placed on the surface of the first metal substrate. The electromagnetic pulse welding equipment is activated so that the second metal substrate collides with the first metal substrate under the drive of Lorentz force, so that the first metal substrate and the second metal substrate undergo solid-state metallurgical bonding in the welding area, and the two sides of the welding area of ​​the second metal substrate are filled with locking structures to form mechanical interlock.

[0009] In at least one embodiment of the present invention, the locking structure is a blind hole or through hole with an inverted conical or dovetail groove cross section.

[0010] In at least one embodiment of the present invention, when processing the locking structure, a rounded corner or chamfer is provided at the cavity opening of the locking structure.

[0011] In at least one embodiment of the present invention, if the locking structure adopts a blind hole design, an exhaust hole is machined at the bottom of the locking structure.

[0012] In at least one embodiment of the present invention, before welding, the welding surfaces of the first metal substrate and the second metal substrate are polished to remove the oxide layer, and then the welding surfaces are cleaned and dried before welding.

[0013] In at least one embodiment of the present invention, the thickness of the pad is 0.5 mm to 2.0 mm.

[0014] In at least one embodiment of the present invention, the angle between the inner inclined surface of the locking structure and the surface direction of the first metal substrate is 30° to 60°.

[0015] In at least one embodiment of the present invention, before welding, the pressure block is located on the longitudinal projection of the two pad blocks, and the locking structure is located between the two pad blocks.

[0016] In at least one embodiment of the present invention, the first metal substrate and the second metal substrate are made of the same or different materials.

[0017] The present invention also proposes a multi-field coupling driven metallurgical-mechanical composite connection device, which is used to realize the multi-field coupling driven metallurgical-mechanical composite connection method, including an electromagnetic pulse welding device, a coil, an insulating cloth, a pad, and a pressure block.

[0018] Compared with the prior art, the beneficial effects of the present invention are: The multi-field coupling driven metallurgical-mechanical composite joining method proposed in this invention achieves solid-state metallurgical bonding in the welding area by setting locking structures on both sides of the welding center of the first metal substrate and using an electromagnetic pulse welding device to drive the second metal substrate to impact at high speed. Simultaneously, the material on both sides of the second metal substrate is embedded in the locking structures to form a reliable mechanical interlock. This method converts the kinetic energy originally dissipated in the edge region during electromagnetic pulse welding into mechanical deformation energy, achieving enhanced connection strength without additional energy input. The connection can be completed within seconds or even microseconds, aligning with the concepts of green manufacturing and maximizing energy efficiency. Furthermore, it eliminates the need for easily aging and poorly temperature-resistant polymers. The adhesive forms a pure metal composite connection structure with excellent high temperature resistance, radiation resistance, and chemical corrosion resistance, effectively solving the problem of reduced reliability of traditional adhesive welding structures under extreme service conditions such as around aero-engines and in space environments. Its mechanical locking area is an interference fit structure with direct and tight metal contact, which has significantly lower contact resistance than adhesive layers and a larger effective metal contact area, which can greatly improve the electrical and thermal conductivity of the joint. It has a decisive advantage in the connection scenarios of new energy vehicle battery pack busbars and other new energy three-electric systems with stringent requirements for high current transmission and electrothermal performance, and achieves efficient utilization of waste energy at the edge of electromagnetic pulse welding. Attached Figure Description

[0019] Figure 1 This is a process flow diagram of the present invention; Figure 2 This invention relates to a dissimilar material riveting and welding process structure based on electromagnetic pulses; Figure 3 This is a cross-sectional schematic diagram of the electromagnetic pulse welding-mechanical riveting composite connection assembly of the present invention; Figure 4 This is a partially enlarged view of the locking structure of the present invention; Figure 5 This is a cross-sectional view of the connector after the connection is completed according to the present invention.

[0020] Explanation of reference numerals in the attached figures: 1. First metal substrate; 11. Locking structure; 111. Chamfer; 2. Second metal substrate; 3. Electromagnetic pulse welding equipment; 31. Coil; 32. System resistor; 33. System capacitor; 34. System inductor; 4. Insulating cloth; 5. Pad; 6. Press block; 7. Interface wave structure. Detailed Implementation

[0021] The accompanying drawings in this invention are not strictly drawn to scale, and the specific dimensions and quantity of each structure can be determined according to actual needs. The drawings described in this invention are merely structural schematic diagrams.

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "inner," "outer," "upper," "lower," "far," "near," "front," and "rear" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] Electromagnetic pulse welding (MPW), as an advanced high-speed solid-state joining technology, utilizes the Lorentz force generated by a high-energy electromagnetic field to drive a workpiece (typically a flyplate) to impact a substrate at high speed within microseconds. At the impact point, due to the jet effect generated by the high-speed impact, the oxide film on the metal surface is removed, and the interatomic distance reaches the bonding range, thereby achieving metallurgical bonding. This technology has significant advantages such as no heat-affected zone, high joint strength, and suitability for joining dissimilar metals. However, in practical engineering applications, existing electromagnetic pulse welding technology suffers from the following significant technical bottlenecks:

[0025] 1. Limitations of the Effective Welding Window: The formation of electromagnetic pulse welding is highly dependent on the collision velocity and collision angle. Effective metallurgical bonding can only be achieved when both parameters fall within a specific "welding window." In welding processes driven by flat or plate coils, the magnetic field pressure distribution typically exhibits a "high in the middle, low at the edges" characteristic, and the collision angle dynamically changes with the deformation of the flyplate. This means that welding conditions are usually met only within a certain area at the collision center (i.e., an elliptical or runway-shaped area) to form a strong solid-phase weld.

[0026] 2. The hazards of the "unbonded zone" at the edge: In the area extending laterally from the welded region, although the fly plate still impacts the substrate at a high speed, due to excessive impact angle or insufficient impact pressure, the metal material undergoes violent plastic flow but fails to form an interatomic metallurgical bond. This "fitted but unwelded" edge area forms a natural gap. When the joint is subjected to tensile stress (peeling force) perpendicular to the plate surface or fatigue load, this gap will generate significant stress concentration, becoming the source of crack initiation.

[0027] 3. Poor anti-peeling performance: Once an edge crack initiates, it will rapidly propagate towards the central metallurgical bond zone, leading to brittle tearing failure of the joint (similar to tearing adhesive tape). Especially for dissimilar metal connections such as aluminum-steel and copper-aluminum, the central weld often has a micron-sized brittle intermediate layer, which is already weak in impact and peeling resistance. The presence of unbonded areas at the edges further exacerbates this risk, severely restricting the reliability of this technology in load-bearing structural components.

[0028] In summary, while existing electromagnetic pulse welding technology has achieved high-quality connections in the central region, it has failed to effectively utilize the plastic deformation energy in the edge region, and the unbonded areas at the edges result in poor joint anti-peeling performance.

[0029] The best solution to the problem of limited performance in MPW (Multi-Purpose Welded Wall) technology is adhesive bonding, where structural adhesive is applied to the unbonded areas. However, this method still has the following drawbacks: 1. Process efficiency and production cycle time: Adhesives typically require curing time. Even fast-curing adhesives require heating or resting, which can disrupt continuous production lines (requiring the addition of curing ovens or buffer zones). Furthermore, extremely high surface cleanliness requirements (degreasing and oil removal) are necessary before application, increasing the pretreatment process.

[0030] 2. Aging and Environmental Adaptability: Adhesives are high-molecular materials (polymers). Aging: Over time, they become brittle and powdery; Temperature Sensitive: They become brittle (easily crack) at extremely cold temperatures and soften (strength drops sharply) at high temperatures. Most structural adhesives fail above 200℃;

[0031] 3. Electrical and thermal conductivity: Structural adhesives are typically insulators (or have very poor electrical conductivity). Applying adhesive occupies contact area, hindering the lateral transfer of current and heat.

[0032] 4. Energy efficiency: Adhesive welding requires additional materials (adhesive) and additional energy (curing heat). It is evident that although adhesive bonding can also improve peel resistance, this invention provides an all-metal transient composite bonding solution that is free from aging risks, resistant to extreme environments, and requires no curing waiting period, thus breaking through the application bottleneck of polymer materials under harsh working conditions.

[0033] Combination Figures 1 to 5 As shown, a multi-field coupling driven metallurgical-mechanical composite connection method is used for connecting a first metal substrate 1 and a second metal substrate 2, including the following steps: Based on the dimensional characteristics (thickness, width, etc.) and connection requirements (service environment, assembly characteristics, connection strength, etc.) of the first metal substrate 1 and the second metal substrate 2, a suitable locking structure 11 (hole, slot, pit, etc., including blind hole, through hole, etc.) is designed. The design focus is on determining the non-welding area on the first metal substrate 1, which is usually located on both sides of the welding center. Locking structures 11 are machined on both sides of the welding center of the welding surface of the first metal substrate 1. The locking structures 11 include through holes, blind holes or grooves. Specifically, the machining method can be precision manufacturing means such as numerical control machining (CNC), laser machining or electrical discharge machining. The locking structure 11 on the first metal substrate 1 is deburred and cleaned to ensure surface smoothness and avoid stress concentration. An insulating cloth 4 is placed on the coil 31 of the electromagnetic pulse welding equipment 3. The second metal substrate 2 is placed on the insulating cloth 4, and pads 5 are placed on both sides of the welding area on the surface of the second metal substrate 2. Then, the locking structure 11 of the first metal substrate 1 is placed on the pads 5 with the bottom facing down, ensuring that the effective magnetic field area of ​​the coil covers the central welding area and completely covers the pre-made locking structures 11 on both sides of the first metal substrate 1. Then, a pressure block 6 is placed on the surface of the first metal substrate 1. The centering can be achieved by laser during the setting process. The electromagnetic pulse welding equipment 3 is activated to charge the capacitor bank to a preset voltage (10kV-25kV). Then, the discharge switch is triggered. In a very short time (microseconds), a high-frequency pulse current flows through the coil 31, inducing a high-strength magnetic field and generating eddy currents on the second metal substrate 2. Driven by a huge Lorentz force, the second metal substrate 2 gains high-speed kinetic energy of hundreds of meters per second. At this time, two different connection forms will appear: In the central region, the second metal substrate 2 and the first metal substrate 1 undergo a high-speed tilting collision, generating a metal jet that carries away the surface oxides, achieving solid-state metallurgical bonding at the interatomic distance; In the two side regions, the material of the second metal substrate 2 undergoes violent high-strain-rate plastic flow driven by the multi-field coupling of inertial force and residual electromagnetic force, filling the locking structure 11 in the first metal substrate 1 at high speed, and undergoing upsetting or springback after impacting the bottom of the hole, forming a stable macroscopic mechanical interlock;

[0034] After the discharge is complete, the power supply to the electromagnetic pulse welding equipment 3 is disconnected, and the first metal substrate 1 and the second metal substrate 2, which have been connected, are removed for visual inspection. It is confirmed that the locking structure 11 is fully filled with metal, without macroscopic cracks, flash, or material tearing. Thus, the integrated composite connection of the same or dissimilar materials via welding and riveting is completed. This joint possesses a high-strength metallurgical bond at the center and anti-peel mechanical locking at the edges, achieving comprehensive enhancement of structural performance.

[0035] In traditional MPW (Multi-Metal Wheat Wire) processes, the metal flow at the edge of the welding area is usually uncontrollable, easily leading to defects such as flash or wall thinning. This invention, during a single microsecond-level pulse discharge, relies on the Lorentz force to drive this same physical process, simultaneously achieving microscopic metallurgical bonding and macroscopic mechanical interlocking of the joint. This spatiotemporal synchronization characteristic constitutes a significant process innovation. At the same time, by designing groove / hole structures of specific shapes on the workpiece, the edge metal flow is actively guided and constrained, transforming the originally disordered metal flow into an effective strengthening structure. Furthermore, it fully utilizes the residual kinetic energy and high-speed plastic rheology at the edge of the welding area, which were originally difficult to participate in metallurgical bonding, to drive the metal to fill and lock into the preset cavity, greatly improving the process energy utilization efficiency.

[0036] As an alternative embodiment, the locking structure 11 is a blind hole or through hole with an inverted conical or dovetail groove cross section; the locking structure 11 includes, but is not limited to, an inverted trapezoidal (dovetail) groove with a narrow opening and a wide bottom; the bottom width of the hole / groove is greater than the opening width, which forms the key to "locking" and prevents the material of the second metal substrate 2 from being pulled out.

[0037] As an alternative embodiment, when processing the locking structure 11, a rounded corner or chamfer 111 is provided at the cavity opening of the locking structure 11. The rounded corner or chamfer 111 can prevent the second metal substrate 2 from being sheared by the sharp edge of the locking structure 11 during high-speed impact, ensuring that the material can flow in smoothly. Figure 3 As shown, after discharge, the locking structure 11 in the first metal substrate 1 causes the middle part of the second metal substrate 2 to undergo high-speed plastic deformation along the Z-axis and impact the center of the first metal substrate 1 at high speed. Since the Z-axis of the first metal substrate 1 is constrained by the pressure block 6, no displacement occurs. Therefore, an annular weld bead is formed in the center. The second metal substrate 2 continues to undergo plastic deformation along both sides of the coil. When it flows to the locking structure 11, the metal flows quickly and fills the locking structure 11, forming a riveting structure.

[0038] As an alternative embodiment, if the locking structure 11 adopts a blind hole design, an exhaust hole is machined at the bottom of the locking structure 11 to avoid the air compression effect inside the locking structure 11 from hindering the metal flow due to high-speed filling.

[0039] As an alternative embodiment, before welding, the welding surfaces of the first metal substrate 1 and the second metal substrate 2 are polished with sandpaper or a wire brush to remove the dense oxide layer on their surfaces; then, the polished surfaces are thoroughly cleaned with anhydrous ethanol (or acetone) to remove oil, metal debris and other impurities, and then air-dried or blow-dried to ensure that the surfaces to be joined are in a clean, dry and activated state, creating microscopic conditions for solid-state metallurgical bonding.

[0040] As an alternative embodiment, the thickness of the pad 5 is 0.5mm~2.0mm. Setting the thickness of the pad 5 to 0.5mm~2.0mm can precisely control the initial assembly gap between the second metal substrate 2 and the first metal substrate 1, ensuring that the collision speed and collision angle during the welding process are within the optimal welding window, and stably achieving solid-state metallurgical bonding in the central region; at the same time, it reserves reasonable space for the plastic flow of metal in the edge region, ensuring that the material flows smoothly into the locking structure 11 to form a mechanical interlock, avoiding insufficient impact energy and poor welding bonding due to too small a gap, or uncontrolled deformation of the flyplate and an increase in joint defects due to too large a gap, thus taking into account both welding forming quality and process stability.

[0041] As an alternative embodiment, the angle between the inner inclined surface of the locking structure 11 and the surface direction of the first metal substrate 1 is 30°~60°. Controlling the angle between the inner inclined surface of the locking structure 11 and the surface direction of the first metal substrate 1 at 30°~60° can ensure that the material of the second metal substrate 2 smoothly fills the locking structure 11 under high-speed impact, avoiding flow obstruction and incomplete filling due to too small an angle, or material shearing and fracture due to too large an angle. It can also form a reliable self-locking shape, significantly improving the joint's anti-peeling and anti-pull-out capabilities, and strengthening the mechanical fitting effect. At the same time, it reduces the stress concentration at the edge of the locking structure 11, improves the structural strength and service life, and takes into account both processability and mechanical properties.

[0042] As an alternative embodiment, before welding, the pressure block 6 is located on the longitudinal projection of the two pad blocks 5, and the locking structure 11 is located between the two pad blocks; the pressure block 6 can accurately position and rigidly constrain the first metal substrate 1 to prevent displacement, warping or bouncing during welding, and ensure welding accuracy and interface uniformity; the locking structure 11 is completely within the effective magnetic field and plastic deformation zone of the coil, ensuring that the edge metal is fully filled and tightly fitted, avoiding mechanical interlock failure due to positional deviation; the welding force distribution is optimized, the joint consistency and connection reliability are improved, and the defect rate is reduced.

[0043] As an alternative embodiment, the first metal substrate 1 and the second metal substrate 2 are made of the same or different materials. This method is applicable to the connection of the same or different metal substrates, breaking through the limitations of traditional welding technology on material compatibility, and can achieve efficient connection of lightweight and high-strength materials such as aluminum alloys, magnesium alloys, and high-strength steel. Addressing the problems of brittle intermetallic compounds and poor joint reliability in dissimilar metal connections, a composite structure combining metallurgical bonding and mechanical interlocking provides dual safety redundancy, improving the impact resistance and fatigue resistance of the joint. This meets the connection needs of lightweight dissimilar composite structures in aerospace, new energy vehicles, rail transportation, and other fields, broadening the application scope of electromagnetic pulse welding technology.

[0044] The present invention also proposes a multi-field coupling driven metallurgical-mechanical composite connection device for realizing the above connection method, including an electromagnetic pulse welding device 3, a coil 31, an insulating cloth 4, a pad 5, and a pressure block 6.

[0045] like Figure 2As shown, the system resistor 32, system capacitor 33, system inductor 34, and trigger switch constitute an electromagnetic pulse discharge system. When the trigger switch is closed, a strong instantaneous current is released, flowing through coil 31 and forming an induced magnetic field around coil 31. Since there is an insulating cloth 4 separating coil 31 from the second metal substrate 2, breakdown will not occur. However, since the second metal substrate 2 is very close to coil 31, eddy currents will be generated on the second metal substrate 2. The direction of the eddy currents is opposite to the direction of the current flow on coil 31. Therefore, the second metal substrate 2 will be driven by the Lorentz force to move in the opposite direction to coil 31. At this time, the two ends of the second metal substrate 2 are restricted by the pads 5. Therefore, only the middle region undergoes plastic deformation and impacts the first metal substrate 1. At this time, the first metal substrate 1 is fixed by the pressure block 6 and will not deform. Therefore, the impact force is concentrated on the surface where the second metal substrate 2 and the first metal substrate 1 are in contact. Atomic diffusion occurs in the central part to form a metallurgical bond between the metals. The second metal substrate 2 continues to flow to both sides and flows into the locking structure 11 to form a riveting. At this point, the electromagnetic pulse riveting process is complete.

[0046] Dissimilar metal connection interfaces, such as Figure 5 As shown, the connection mainly includes two areas: the metallurgical bonding area, also known as the welding area 7, and the locking structure filling area, also known as the riveting area 11. The welding area has MPW's unique interface wave structure 7 on both sides, which is to improve the tensile strength of the locking structure 11.

[0047] The above embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit them. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions implemented in the present invention, and should all be covered within the protection scope of the present invention.

Claims

1. A multi-field coupling driven metallurgical-mechanical composite connection method for connecting a first metal substrate and a second metal substrate, characterized in that, Includes the following steps: Locking structures are machined on both sides of the welding center of the welding surface of the first metal substrate. The locking structures include through holes, blind holes, or grooves. Deburr and clean the locking structure on the first metal substrate; An insulating cloth is placed on the coil of the electromagnetic pulse welding equipment, a second metal substrate is placed on the insulating cloth, and pads are placed on both sides of the welding area on the surface of the second metal substrate. Then, the locking structure of the first metal substrate is placed on the pads with the locking structure facing down, and the effective magnetic field of the coil is ensured to cover the central welding area and the locking structure. Subsequently, a pressure block is placed on the surface of the first metal substrate. The electromagnetic pulse welding equipment is activated, causing the second metal substrate to collide with the first metal substrate under the drive of Lorentz force, so that the first metal substrate and the second metal substrate undergo solid-state metallurgical bonding in the welding area, and the two sides of the welding area of ​​the second metal substrate are filled with locking structures to form mechanical interlock.

2. The multi-field coupling driven metallurgical-mechanical composite connection method as described in claim 1, characterized in that, The locking structure is a blind hole or through hole with an inverted conical or dovetail groove cross section.

3. The multi-field coupling driven metallurgical-mechanical composite connection method as described in claim 1, characterized in that, When machining the locking structure, rounded corners or chamfers are provided at the cavity opening of the locking structure.

4. The multi-field coupling driven metallurgical-mechanical composite connection method as described in claim 1, characterized in that, If the locking structure adopts a blind hole design, an exhaust hole is machined at the bottom of the locking structure.

5. The multi-field coupling driven metallurgical-mechanical composite connection method as described in claim 1, characterized in that, Before welding, the welding surfaces of the first and second metal substrates are polished to remove the oxide layer. Then the welding surfaces are cleaned and dried before welding.

6. The multi-field coupling driven metallurgical-mechanical composite connection method as described in claim 1, characterized in that, The thickness of the pad is 0.5mm to 2.0mm.

7. The multi-field coupling driven metallurgical-mechanical composite connection method as described in claim 2, characterized in that, The angle between the inner inclined surface of the locking structure and the surface of the first metal substrate is 30°~60°.

8. The multi-field coupling driven metallurgical-mechanical composite connection method as described in claim 1, characterized in that, Before welding, the pressure block is located on the longitudinal projection of the two pad blocks, and the locking structure is located between the two pad blocks.

9. The multi-field coupling driven metallurgical-mechanical composite connection method as described in claim 1, characterized in that, The first metal substrate and the second metal substrate are made of the same or different materials.

10. A multi-field coupling driven metallurgical-mechanical composite connection device, characterized in that, The device includes an electromagnetic pulse welding apparatus, a coil, an insulating cloth, a pad, and a pressure block, and is configured to perform the multi-field coupling driven metallurgical-mechanical composite connection method according to any one of claims 1 to 9.

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