Dissimilar material connection method based on additive and subtractive cooperative regulation and control of joint performance
By constructing micro-textures on the surface of metal workpieces and forming a composite additive layer on the surface of resin workpieces, combined with the stir friction welding process, the problem of poor bonding effect at the interface of dissimilar materials is solved, and high-strength and durable connection of dissimilar materials is achieved.
Patent Information
- Application Number
- CN202511105617.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-07
- Publication Date
- 2025-09-19
AI Technical Summary
Existing technologies are difficult to use in the field of aviation manufacturing. Traditional riveting, screwing and other technologies are difficult to use in the connection of dissimilar materials. Existing technologies have poor interface compatibility, resulting in poor interface bonding, which leads to poor interface bonding effect of dissimilar materials connection, and cannot meet the requirements of the new generation of aircraft for weight reduction, high strength and long life.
A method of collaboratively regulating joint performance by adding and subtracting materials is adopted. By constructing a micro-texture on the surface of the metal workpiece and forming a composite additive layer on the surface of the resin workpiece, the metal and resin workpieces are connected using a stir friction welding process to form a deposition layer of aluminum alloy debris and CFRP, achieving cross-scale compatibility and chemical bonding.
It improves the interface bonding ability and dynamic load reliability of dissimilar material connections, solves the universal connection problem of thermoplastic/thermosetting resins, and enhances the strength and durability of the connection joints.
Smart Images
Figure CN120663543A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of dissimilar material connection, and specifically relates to a dissimilar material connection method based on collaborative regulation of joint performance by adding and subtracting materials. Background Art
[0002] In the field of lightweight aviation manufacturing, the reliable connection between aluminum alloys and carbon fiber reinforced resin-based composites (CFRP) is the key to improving structural performance. Traditional mechanical fastening (such as riveting and bolting) and adhesive bonding processes have significant defects: mechanical connections add extra weight and are prone to stress concentration, while adhesive bonding faces problems such as adhesive aging, poor weather resistance, and environmental pollution. These methods are difficult to meet the core requirements of the new generation of aircraft for weight reduction, high strength, and long life. Although existing welding technology can achieve connection, it is still limited by three major bottlenecks: poor interface compatibility, low material adaptability, and insufficient dynamic load reliability. In this regard, how to enhance the bonding effect of the interface between dissimilar materials is the current main exploration path.
[0003] Currently, single-sided optimization strategies are commonly used to enhance the interfacial bonding of dissimilar materials. For example, existing literature, such as CN202410649021X, CN2024116123151, CN2022106927788, and CN2021109633137, employs micro-nanostructures (e.g., laser etching and anodizing) on metal surfaces to enhance mechanical anchoring, or introduces active coatings (e.g., electroless plating and plasma treatment) onto CFRP surfaces to improve chemical bonding. However, existing single-sided metal modification techniques rely heavily on resin flow to fill the microstructures, making them poorly compatible with low-flow thermosetting resins and unable to address the weak bonding at the resin / fiber interface. Existing single-sided CFRP modification requires specific functional groups to achieve chemical bonding, resulting in poor modification effectiveness for resins with inactive functional groups. In summary, existing approaches fail to simultaneously control the cross-scale compatibility of the metal-resin interface, fail to systematically address the universal joining challenges of thermoplastic / thermosetting resins, and suffer from poor dynamic load reliability of the joints. Summary of the Invention
[0004] At least in order to solve the technical problems mentioned in the background technology, the purpose of the present invention is to provide a method for connecting dissimilar materials based on the coordinated regulation of joint performance by adding and subtracting materials.
[0005] The present invention adopts the following technical solutions.
[0006] A method for joining dissimilar materials based on collaboratively regulating joint performance by adding and subtracting materials, comprising: Step 1: Producing surface micro-texture on the connecting surface of the metal workpiece using a subtractive process; Step 2: forming a composite additive layer on the surface of the resin workpiece using a friction stir additive process, wherein metal debris is dispersed in the composite additive layer; Step 3: After clamping the metal workpiece and the resin workpiece, the metal workpiece and the resin workpiece are connected together using a stir friction welding process.
[0007] Preferably, the particle size of the metal chips is 0.1-3 mm.
[0008] Preferably, in step 2, the rotation speed of the stirring tool is controlled to be 600-2000 r / min, the travel speed of the stirring tool is controlled to be 20-100 mm / min, the downward pressure of the stirring tool is controlled to be 1-2 mm, and the wire feeding speed is controlled to be 1-3.5 m / min.
[0009] Furthermore, the wire used in the friction stir additive process is a composite wire with a metal skin coated with a resin material, and the volume ratio of the metal skin to the resin material of the composite wire is 1.3:1~2:1.
[0010] Furthermore, the stirring tool includes a stirring head and a static shoulder mounted on the stirring head. The outer wall of the lower section of the stirring head is provided with a spiral groove, and the wire feeding hole is provided on the static shoulder and communicates with the spiral groove. During the operation of the stirring tool, the composite wire material fed in is cut into fragments under the rotation of the stirring head and embedded in the resin workpiece, eventually forming a composite additive layer.
[0011] Preferably, in step 1, a nanosecond pulsed fiber laser is used for laser etching to obtain a surface microtexture with a tooth-like structure, wherein the groove width of the tooth-like structure is 20-40 μm, the groove depth is 50-200 μm, the tooth width is 10-20 μm, and the tooth depth is 10-20 μm.
[0012] Preferably, during the laser etching process, the laser power is 10-40 W, the scanning speed is 10-35 mm / s, the number of scans is 1-10 times, and the scanning interval is 100-2000 μm.
[0013] Preferably, during welding, when the spindle rotation speed reaches 600-1200 r / min, start pressing down 0.1-0.5 mm, maintain it for 2-10 seconds after reaching the program-set pressing position, then move along the welding direction at a welding speed of 100-500 mm / min, maintain it for 2-10 seconds after reaching the welding end position, and finally control the spindle to lift and slowly reduce the rotation speed.
[0014] Preferably, the metal workpiece is made of aluminum alloy, and the resin workpiece is made of CF-PA66.
[0015] Furthermore, the composite additive layer has a plurality of arc-shaped protrusions that are arranged at intervals and distributed regularly, and the arc-shaped protrusions are formed during the friction stir additive process.
[0016] Beneficial effects: By constructing a micro-nano structure (micro-texture) on the metal surface, and forming a composite deposition layer with metal debris on the CFRP (resin) surface by the specific process of the present invention, and then connecting the two together through a stir friction welding process, a breakthrough is made in the material adaptability challenge in the metal / CFRP connection, and it is convenient to synchronously regulate the cross-scale compatibility of the metal-resin interface, systematically solve the universal connection problem of thermoplastic / thermosetting resins, and improve the dynamic load reliability of the connection joint; in the present invention, during the rotation and movement of the stir friction tool, the surface of the additive area presents a regular arc-shaped protrusion structure, which is composed of a large amount of aluminum alloy debris, and the CFRP surface is formed by a deposition layer formed by a mixture of aluminum alloy debris and melted and re-solidified CFRP. The groove surface of the resin workpiece is enriched with alumina particles, and can be connected to the CFRP matrix through CO-Al bonds, further improving the interface bonding ability. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 Schematic diagram of surface microtexture on the metal workpiece in Example 1; Figure 2 Schematic diagram of the surface microtexture on the metal workpiece in Example 1 (surface and cross-sectional morphology) under an electron microscope; Figure 3 Schematic diagram of the composite additive layer on the resin workpiece in Example 1; Figure 4 Schematic diagram of the composite additive layer on the metal workpiece in Example 1 (cross section) by electron microscope; Figure 5 The composite additive layer bonding and EDS line scanning analysis results of the resin workpiece in Example 1; Figure 6 This is a partial schematic diagram of the stirring tool used in Example 1. DETAILED DESCRIPTION
[0018] The following is a clear and complete description of the technical solutions of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. Example 1
[0019] A method for joining dissimilar materials based on collaboratively regulating joint performance by adding and subtracting materials, comprising: Step 1: Using a subtractive process to produce a surface micro-texture on the connecting surface of a metal workpiece 3 (A6061 aluminum alloy); Step 2: forming a composite additive layer on the surface of the resin workpiece 1 (CF-PA66 carbon fiber reinforced PA66 composite material) using a friction stir additive process, wherein metal debris is dispersed in the composite additive layer; Step 3: After clamping the metal workpiece 3 and the resin workpiece 1, the metal workpiece 3 and the resin workpiece 1 are connected together using a stir friction welding process.
[0020] The specific steps of step 1 of this embodiment are as follows: Use 200-2000# sandpaper to grind the pre-laser etching area on the aluminum alloy surface to remove the oxide film on the aluminum alloy surface to ensure consistent surface roughness, reduce the laser reflectivity on the aluminum alloy surface, and improve laser etching efficiency; The aluminum alloy surface was ultrasonically cleaned with acetone for 5-20 minutes to remove oil and impurities, then rinsed with anhydrous ethanol and dried. Immerse the aluminum alloy in a 5-15 wt.% NaOH solution for 2-10 minutes to remove the oxide layer on the surface of the aluminum alloy, promote the combination of deionized water and aluminum, and improve the generation efficiency of -OH; Immerse the aluminum alloy with the oxide film removed in a 10-40 wt.% HNO3 solution for 1-5 minutes to neutralize the NaOH solution on the surface of the aluminum alloy and remove any remaining stains. Immerse the cleaned aluminum alloy in constant temperature deionized water for 1-20 min. The temperature of the deionized water is kept constant at 60-100 °C. The surface of the aluminum alloy was laser etched using a nanosecond pulsed fiber laser. The process parameters, including laser power, scanning speed, number of scans, and scanning spacing, were set to 30 W for laser power, 30 mm / s for scanning speed, 5 times for scanning, and 160 μm for scanning spacing. The surface microtexture with the groove 4 size (without considering the error) of 30 μm in width and 70 μm in depth and the tooth 5 size (15 μm × 15 μm) was obtained, as shown in Figure 2. Figure 1 and 2 As shown; The specific steps of step 2 of this embodiment are as follows: Clean the surface of CF-PA66 (resin workpiece 1) with alcohol and ultrasonic cleaning for 5-20 minutes to remove oil and impurities. The CF-PA66 surface was processed using a wire-feed-based friction stir additive manufacturing device. Figure 6This is a schematic diagram of a specially designed stirring tool (including a stirring head 11 and a stationary shoulder 12 mounted on the stirring head 11, a spiral groove 14 provided on the outer wall of the lower section of the stirring head, and a wire feed hole provided on the stationary shoulder 12 and communicating with the spiral groove 14). As an aluminum alloy wire 13 (2 mm in diameter) is continuously fed in, the aluminum alloy wire 13 is cut into chips by the stirring tool and the stationary shoulder. The aluminum alloy chips are fed into the PA66 matrix along the spiral grooves on the surface of the stirring tool. Under the action of the rotating stirring action of the stirring tool, they are evenly distributed on the surface of the CF-PA66, forming an intermixed structure, as shown in FIG. Figures 3 to 5 As shown in the figure, the main process parameters during the friction stir additive process include the stirring tool rotation speed, travel speed, downward pressure, and aluminum alloy wire feed speed, which are set to 800 r / min, 50 mm / min, 1 mm downward pressure, and 2 m / min, respectively. The resulting composite additive layer 2 has a number of regularly spaced and spaced circular arc-shaped protrusions, which are formed during the friction stir additive process.
[0021] The specific steps of step 3 of this embodiment are as follows: Use a special fixture to overlap and clamp the workpieces (metal workpiece 3 on top, resin workpiece 1 on the bottom), ensuring that the overlap area covers the surface treatment areas of the materials on both sides; The spindle starts to rotate, and after the rotation speed reaches 1000r / min, it begins to press down 0.5mm. After reaching the program-set pressing position, it is maintained for 8s. Then it moves along the welding direction at a welding speed of 300mm / min. After reaching the welding end position, it is maintained for 5s. The spindle is lifted and the rotation speed is slowly reduced, and the welding is completed. Example 2
[0022] A method for connecting dissimilar materials based on the coordinated regulation of joint performance by additive and subtractive methods. Referring to Example 1, the method differs from Example 1 in that the wire used in the stir friction additive process is a composite wire with a metal skin coated with a resin material, the volume ratio of the metal skin to the resin material of the composite wire is 1.3:1, and the thickness of the metal skin of the composite wire is 0.5 mm. Example 3
[0023] A method for connecting dissimilar materials based on the coordinated regulation of joint performance by additive and subtractive methods, referring to Example 1, differs from Example 1 in that: the wire used in the stir friction additive process is a composite wire material with a metal skin coated with a resin material, the volume ratio of the metal skin of the composite wire to the resin material is 1.5:1, and the thickness of the metal skin of the composite wire is 0.5 mm. Example 4
[0024] A method for connecting dissimilar materials based on the coordinated regulation of joint performance by additive and subtractive methods. Referring to Example 1, the method differs from Example 1 in that the wire used in the stir friction additive process is a composite wire with a metal skin coated with a resin material, the volume ratio of the metal skin to the resin material of the composite wire is 2:1, and the thickness of the metal skin of the composite wire is 0.5 mm. Example 5
[0025] A method for connecting dissimilar materials based on the coordinated regulation of joint performance by additive and subtractive methods. Referring to Example 1, the method differs from Example 1 in that the wire used in the stir friction additive process is a composite wire with a metal skin coated with a resin material, the volume ratio of the metal skin to the resin material of the composite wire is 3:1, and the thickness of the metal skin of the composite wire is 0.5 mm.
[0026] Comparative Example: Based on Example 1, the metal scraps were omitted.
[0027] Mechanical properties tests were performed on the samples prepared in the examples and comparative examples. The results showed that the tensile shear strength of the sample in Example 1 was 31.5 MPa, the tensile shear strength of the sample in Example 2 was 27.9 MPa, the tensile shear strength of the sample in Example 3 was 46.8 MPa, the tensile shear strength of the sample in Example 4 was 42.5 MPa, the tensile shear strength of the sample in Example 5 was 28.1 MPa, and the tensile shear strength of the sample in the comparative example was 18 MPa.
[0028] Due to the huge differences in physical, chemical, and mechanical properties between metals and CFRP, direct connections have almost no strength. Therefore, most scholars use surface modification of metals or CFRP to improve the degree of mechanical interlocking at the interface or enhance interfacial compatibility to increase the connection strength. In the present invention, laser etching is performed on the aluminum alloy side to construct a regular groove morphology on the aluminum alloy surface, thereby increasing the surface roughness and achieving a strong mechanical interlocking effect; the groove surface is enriched with alumina particles, which can be connected to the CFRP matrix via CO-Al bonds, thereby improving the chemical bonding ability of the interface; through friction stir additive treatment on the CFRP surface, a deposition layer formed by a mixture of aluminum alloy debris and melted and resolidified CFRP is constructed on the CFRP surface. During the rotation and movement of the friction stir welding tool, the additive surface presents a regular arc-shaped protrusion structure composed of a large amount of aluminum alloy debris, which facilitates the contact between the aluminum alloy surface after subtraction and the CFRP after additive and stir friction welding. During the welding process, under the pre-pressure of the stirring head, the protruding debris on the CFRP surface can be pre-embedded into the groove, promoting the two-way mechanical interlocking of the aluminum alloy and CFRP (aluminum alloy-CFRP: the aluminum alloy's tooth structure bites the CFRP matrix; CFRP-aluminum alloy: the CFRP's resin matrix fills the aluminum alloy groove, and the aluminum alloy debris and the CFRP's carbon fiber are inserted into the groove, playing an interlocking role). As the interface temperature gradually increases, under the pressure and heating of the stirring head, the plastic deformation capacity of the aluminum alloy side interface increases, which is conducive to the aluminum alloy debris on the CFRP surface to penetrate into the non-groove position of the aluminum alloy surface. Under the action of temperature, good aluminum-aluminum diffusion is achieved, enhancing chemical bonding and mechanical interlocking. In particular, in the schemes of Examples 2 to 4, a composite wire with a metal skin coated with a resin material is used, so that a large number of "ring-shaped" metal debris structures are dispersed in the formed composite additive layer, and the resin materials at both ends of the metal debris are connected to the resin substrate, similar to the metal skin of the metal debris being tied by the resin material. Some metal debris can be more stably connected to the micro-texture of the metal workpiece during the subsequent welding process, thereby significantly improving the dynamic load reliability and interface bonding ability of the connection joint, and by regulating the metal and resin ratio of the composite wire, the dynamic load reliability and interface bonding ability of the connection joint can be effectively regulated.
Claims
1. A method for connecting dissimilar materials based on collaborative control of joint performance by adding and subtracting materials, characterized in that: Steps include: Step 1: Producing surface micro-texture on the connecting surface of the metal workpiece using a subtractive process; Step 2: forming a composite additive layer on the surface of the resin workpiece using a friction stir additive process, wherein metal debris is dispersed in the composite additive layer; Step 3: After clamping the metal workpiece and the resin workpiece, the metal workpiece and the resin workpiece are connected together using a stir friction welding process.
2. The method for connecting dissimilar materials according to claim 1, characterized in that: The particle size of the metal chips is 0.1-3 mm.
3. The method for connecting dissimilar materials according to claim 1, characterized in that: In step 2, the rotation speed of the stirring tool is controlled to 600-2000 r / min, the travel speed of the stirring tool is controlled to 20-100 mm / min, the downward pressure of the stirring tool is controlled to 1-2 mm, and the wire feeding speed is controlled to 1-3.5 m / min.
4. The method for connecting dissimilar materials according to claim 3, characterized in that: The wire used in the friction stir additive process is a composite wire with a metal skin coated with a resin material. The volume ratio of the metal skin to the resin material of the composite wire is 1.3:1~2:1; or, the wire used in the friction stir additive process is a solid metal wire with a diameter not greater than 2 mm.
5. The method for connecting dissimilar materials according to claim 4, characterized in that: The stirring tool includes a stirring head and a static shaft shoulder mounted on the stirring head. The outer wall of the lower section of the stirring head is provided with a spiral groove, and the wire feeding hole is provided on the static shaft shoulder and communicates with the spiral groove. During the operation of the stirring tool, the composite wire material fed in is cut into fragments under the rotation of the stirring head and embedded in the resin workpiece, eventually forming a composite additive layer.
6. The method for connecting dissimilar materials according to claim 5, characterized in that: In step 1, a nanosecond pulsed fiber laser is used for laser etching to obtain a surface microtexture with a tooth-like structure. The groove width of the tooth-like structure is 20-40 μm, the groove depth is 50-200 μm, the tooth width is 10-20 μm, and the tooth depth is 10-20 μm.
7. The method for connecting dissimilar materials according to claim 6, characterized in that: During the laser etching process, the laser power is 10-40 W, the scanning speed is 10-35 mm / s, the number of scans is 1-10 times, and the scanning spacing is 100-2000 μm.
8. The method for joining dissimilar materials according to any one of claims 1 to 7, wherein: During welding, when the spindle rotation speed reaches 600-1200 r / min, start pressing down 0.1-0.5 mm, maintain it for 2-10 seconds after reaching the program-set pressing position, then move along the welding direction at a welding speed of 100-500 mm / min, maintain it for 2-10 seconds after reaching the welding end position, and finally control the spindle to lift and slowly reduce the rotation speed.
9. The method for connecting dissimilar materials according to claim 7, characterized in that: The metal workpiece is made of aluminum alloy, and the resin workpiece is made of CF-PA66.
10. The method for connecting dissimilar materials according to claim 8, characterized in that: The composite additive layer has a plurality of arc-shaped protrusions that are arranged at intervals and distributed regularly, and the arc-shaped protrusions are formed during the friction stir additive process.