Aluminum alloy laser-gmaw cold wire synergistic additive manufacturing method

Abstract

The application relates to an aluminum alloy laser-GMAW cold wire synergistic additive manufacturing method, which is based on laser-GMAW composite heat source welding technology, and an independent cold wire feeding device is additionally arranged, the cold wire feeding device and a main welding wire feeding system work independently and synchronously. In the additive manufacturing process, the main wire feeding system feeds the live aluminum alloy main welding wire, and the independent wire feeding device synchronously feeds the non-live aluminum alloy cold wire into a welding pool, and the independent cold wire is used for realizing decoupling separation control of arc energy and material deposition. The application does not need to change the original laser-GMAW composite heat source welding equipment, is convenient to operate, can supplement the deposited material through the cold wire, can significantly improve the material deposition efficiency and the arc energy utilization rate, can respectively regulate the arc energy and the material deposition amount, can accurately control the heat input of the formed piece, can reduce the thermal deformation, can optimize the geometric precision and the mechanical property of the formed piece, is suitable for efficient and high-precision additive manufacturing of various aluminum alloy components, and has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of metal additive manufacturing technology, and in particular to a method for laser-GMAW cold filament co-additive manufacturing of aluminum alloys. Background Technology

[0002] Aluminum alloys possess characteristics such as low density, good plasticity, corrosion resistance, and excellent weldability, making them widely used in large, lightweight structural components in industries such as rail transportation, shipbuilding, and aerospace. These large components are typically enormous in size and complex in structure. Traditional manufacturing methods combining casting, forging, and machining suffer from drawbacks such as cumbersome processes, low material utilization, long production cycles, and high manufacturing costs, making it difficult to meet the demands of modern manufacturing for high efficiency, energy conservation, and lightweight construction.

[0003] Wafer arc additive manufacturing (WAAM) technology, with its significant advantages such as high deposition efficiency, low equipment cost, unrestricted forming size, and suitability for direct forming of large components, has become an important technical approach for the rapid fabrication of large aluminum alloy components. Compared with traditional manufacturing processes, it can significantly shorten the production cycle, improve material utilization, and reduce manufacturing costs. Among them, gas metal arc welding additive manufacturing (GMAW-WAAM) is one of the most widely used processes in aluminum alloy WAAM technology due to its strong equipment versatility and high cladding efficiency.

[0004] The core advantage of arc additive manufacturing lies in its high deposition rate. A higher deposition rate can further improve production efficiency, shorten the manufacturing cycle of large components, and reduce industrial production costs.

[0005] However, traditional GMAW (Glass Wire Additive Manufacturing) processes have the following inherent technical bottlenecks: Improving deposition efficiency typically requires simultaneously increasing welding current and wire feed speed, which leads to a significant increase in heat input to the heat source, resulting in a series of forming and performance defects. This is especially true for aluminum alloys, which have high thermal conductivity, a large coefficient of linear expansion, and a high solidification shrinkage rate, making them extremely sensitive to heat input. Excessive heat input can easily lead to overheating of the molten pool, severe interlayer remelting, coarse grains in the deposited layer, increased residual stress in the component, and significant thermal deformation. It also increases the probability of internal defects such as porosity and oxide inclusions, ultimately resulting in low geometric accuracy and decreased mechanical properties of the formed parts. This makes it difficult to simultaneously achieve the dual technical goals of high deposition rate and low heat input, severely limiting its application in high-precision, high-performance large aluminum alloy components.

[0006] Laser-GMAW composite heat source is a novel, highly efficient, and synergistic heat source. This technology combines the high energy density and precision of laser with the high cladding efficiency, good bridging ability, and low equipment cost of GMAW heat source. By using laser to assist in stabilizing the arc, refining the microstructure, and improving the fluidity of the molten pool, it suppresses spatter and porosity defects during additive manufacturing with a single GMAW heat source. To a certain extent, it improves the forming quality and mechanical properties of aluminum alloy additive parts, and has become a research hotspot in the current high-efficiency additive manufacturing of aluminum alloys.

[0007] However, in practical applications that pursue high deposition rates for large aluminum alloy components, the combined effect of laser and GMAW arc still leads to excessively high molten pool temperature and excessive melting depth, resulting in severe interlayer remelting and repeated reheating. On the one hand, excessive remelting increases energy loss, reducing process energy utilization and production efficiency; on the other hand, repeated high-temperature heating and cooling leads to further coarsening of the aluminum alloy deposited layer grains, increased residual stress accumulation, and a tendency to cause defects such as component warping and cracking, significantly reducing the component's tensile strength, yield strength, and plasticity. In traditional laser-GMAW composite heat source additive manufacturing processes, the GMAW arc energy input and the material deposition process are coupled, making independent control difficult. When it is necessary to increase the deposition rate by increasing the wire feed, the heat source energy of both the laser and the arc must be increased simultaneously, which further exacerbates the problems of molten pool overheating and remelting. If the heat source energy is reduced to decrease remelting, it will lead to insufficient wire melting and a significant decrease in deposition efficiency, making it impossible to achieve the dual goals of high deposition rate and low material remelting. Therefore, existing laser-GMAW composite heat source additive manufacturing technology has not yet broken through the core bottleneck of "high energy input and strong coupling between energy and material deposition", and cannot achieve independent and precise control of deposition efficiency and heat input, making it difficult to meet the industrial additive manufacturing needs of large, high-precision, and high-performance aluminum alloy components. Summary of the Invention

[0008] To address the aforementioned problems, the present invention aims to provide a laser-GMAW cold wire co-processing additive manufacturing method for aluminum alloys. By adding an independent wire feeding device next to the laser-GMAW welding torch, a non-electric aluminum alloy cold wire is simultaneously fed into the molten pool during the conventional laser-GMAW arc deposition process. This achieves decoupling control of the main heat source energy and the cold wire deposition material, ultimately achieving the dual goals of high deposition rate and low material remelting. Simultaneously, it improves energy utilization, precisely controls the heat input and geometric accuracy of the formed part, and optimizes the mechanical properties of the component. This method has significant engineering value and practical significance for improving the efficiency, accuracy, and mechanical properties of additive manufacturing of large aluminum alloy components.

[0009] The technical solution adopted in this invention is as follows:

[0010] The present invention proposes a laser-GMAW cold filament co-processing additive manufacturing method for aluminum alloys, comprising the following steps: Step 1: Select an aluminum alloy sheet with a composition similar to that of the welding wire as the substrate, pre-treat the surface of the substrate, and fix it on the work platform with a clamp to ensure that the substrate is flat and not loose. Step 2: Preheat the pretreated aluminum alloy substrate; Step 3: Add an independent wire feeding mechanism on one side of the laser-GMAW composite welding gun in the forward direction. The independent wire feeding mechanism feeds an aluminum alloy non-electric cold wire that matches the composition of the main welding wire. The front end of the cold wire is located in front of the molten pool and close to the edge of the molten pool. It is fed synchronously with the main welding wire during the additive manufacturing process. Step 4: Set the GMAW additive manufacturing process parameters, welding speed, laser power, laser defocusing amount and cold wire filling speed according to the forming characteristics of aluminum alloy, and ensure that each parameter is matched to achieve decoupling of energy and deposition rate; Step 5: Adjust the laser-GMAW composite welding torch posture, cold wire feeding angle and wire feeding position, and plan the additive manufacturing path; Step 6: Introduce protective gas and adjust the protective gas flow rate; Step 7: Start the laser-GMAW composite heat source and cold wire feeding mechanism to carry out the first layer deposition. After the deposition is completed, use vernier calipers to measure the first layer forming height at multiple points and take the average value as the offset of each layer in the additive manufacturing forming direction. Deposit layer by layer strictly according to the preset path. After each layer is deposited, perform surface cleaning until the additive manufacturing of aluminum alloy components is completed.

[0011] Furthermore, in the laser-GMAW composite heat source additive manufacturing process, the laser heat source and the GMAW arc heat source work together, and the process parameters meet the following conditions: the laser power is 400-600W, the laser defocusing amount is adjustable within the range of 0-2mm, the laser is output in pulse mode with a frequency of 30-50Hz, and the laser pulse width is 1-2.5ms.

[0012] Furthermore, the GMAW power supply adopts a DC reverse polarity mode, the main welding wire feeding speed is 6-10m / min, the welding current is 150-210A, the welding voltage is 18-22V, and the welding speed is 8-12mm / s.

[0013] Furthermore, the cold wire is an aluminum alloy welding wire that matches the main welding wire, and the cold wire feeding speed is 3-5 m / min. The feeding speeds of the cold wire and the main welding wire are independently adjustable.

[0014] Furthermore, the GMAW welding torch is perpendicular to the surface of the aluminum alloy substrate, and the GMAW welding torch and the laser torch head are combined in a paraaxial manner. During the additive manufacturing process, the laser torch head is in front and the GMAW welding torch is behind, with the GMAW welding torch axis and the laser torch head axis forming an angle of 30°-45°. The cold wire is independently fed from the front of the laser-GMAW composite welding torch, with the cold wire axis forming an angle of 20°-30° with the substrate surface. The end of the cold wire is precisely pointed to the front edge of the molten pool, ensuring that the cold wire enters the molten pool smoothly and is fully melted.

[0015] Furthermore, the distance between the end of the main welding wire and the laser filament in the GMAW is 0-1mm to ensure the synergistic effect of the laser and the electric arc; the end of the cold wire lightly touches the edge of the molten pool, the distance between the end of the cold wire and the end of the main welding wire is 0-2mm, and the distance between the end of the cold wire and the surface of the substrate is 0-1mm.

[0016] Furthermore, the protective gas is high-purity argon with a purity of ≥99.99%, and the protective gas flow rate is 20-25 L / min, covering the ends of the main welding wire and the cold wire.

[0017] Furthermore, the preheating temperature of the aluminum alloy substrate is 80-120℃.

[0018] Compared with the prior art, the present invention has the following advantages: 1. Compared with traditional single GMAW heat sources, the laser-GMAW composite heat source used in this invention has significant advantages such as a large process window, strong controllability of energy input, and flexible adjustment. Through the synergistic matching of laser and GMAW arc, the arc energy density and overall energy utilization rate can be effectively improved, avoiding the problems of energy waste or uneven energy distribution of a single heat source. At the same time, the high energy density of the laser can effectively compress the GMAW arc, constrain the arc shape, stabilize the flow of the molten pool and the behavior of pinholes, significantly suppress the spatter and porosity in the additive manufacturing process, ensure that the deposited layer is uniform and dense, has a smooth surface, and reduces typical defects such as incomplete fusion. 2. This invention innovatively introduces an independent, non-electrically powered cold wire, achieving a significant increase in deposition efficiency without increasing the energy input of the main heat source. The melting energy of the cold wire relies entirely on the arc and molten pool heat of the laser-GMAW composite heat source, eliminating the need for additional heating devices or increased energy output of the main heat source to improve the deposition rate. By independently adjusting the feed speeds of the main welding wire and the cold wire, the deposition rate can be flexibly controlled, resulting in an overall deposition efficiency improvement of over 50%, significantly shortening the manufacturing cycle and reducing industrial production costs. 3. This invention achieves decoupled control of energy input and material deposition rate by separating and controlling the main heat source and the independent cold wire, solving the technical pain point of mutual coupling and difficulty in achieving both in existing processes. On the one hand, heat input can be precisely controlled by adjusting the laser power and GMAW arc parameters, reducing thermal deformation and residual stress in the formed parts; on the other hand, the cold wire can absorb some of the heat from the molten pool when melting, reducing the molten pool temperature, refining the grains, and ensuring a uniform and fine structure of the deposited layer. This significantly optimizes the tensile strength, yield strength, plasticity, and other mechanical properties of aluminum alloy additive parts such as 5183, meeting the high-performance requirements of large aluminum alloy components in fields such as rail transportation, shipbuilding, and aerospace, and has significant engineering application value. Attached Figure Description

[0019] Figure 1 This is a schematic diagram illustrating the principle of the laser-GMAW cold filament co-additive manufacturing method for aluminum alloys proposed in this invention. Figure 2 This is a schematic diagram of the macroscopic forming effect of the aluminum alloy additive part manufactured in the embodiment of the present invention; Figure 3 This is a schematic diagram of the microstructure distribution of the aluminum alloy additive part in an embodiment of the present invention; Figure 4 This is a schematic diagram showing the test results of the mechanical properties of the aluminum alloy additive parts in the embodiments of the present invention.

[0020] In the attached figures, the following labels are used: 1-substrate; 2-deposited layer; 3-main welding wire; 4-welding gun; 5-laser gun head; 6-cold wire; 7-working platform. Detailed Implementation

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] like Figure 1As shown, this invention proposes a laser-GMAW cold wire co-processing additive manufacturing method for aluminum alloys. This method uses a laser-GMAW composite heat source as the heat source for aluminum alloy additive manufacturing. The aluminum alloy main welding wire of the GMAW welding torch is energized and melted to form a molten pool. The laser generates an oscillation effect on the molten pool, stabilizing the arc and refining the molten pool grains. An independent wire feeding mechanism is added to one side of the laser-GMAW composite welding torch's forward direction. This mechanism feeds a non-energized aluminum alloy cold wire with a composition matching the main welding wire. The cold wire's tip is located in front of the molten pool and close to its edge. During the additive manufacturing process, it is fed synchronously with the main welding wire. The cold wire is heated and melted by the arc heat of the laser-GMAW composite heat source. The cold wire feeding speed is independently adjustable from the main welding wire feeding speed, achieving decoupled control of arc energy and material deposition rate. Layer-by-layer deposition is performed through a planned, preset additive path until the additive manufacturing of the aluminum alloy component is completed. Specifically, the method includes the following steps: Step 1: Select an aluminum alloy sheet with a composition similar to that of the welding wire as the substrate 1. Pre-treat the surface of the substrate 1 by degreasing, removing oxide film, and polishing to remove surface impurities and oxide layers to avoid forming defects. Then, use a special fixture to fix it on the work platform 7 to ensure that the substrate 1 is flat and not loose.

[0023] Step 2: Preheat the pretreated aluminum alloy substrate 1 to a temperature of 80-120℃ to reduce defects such as cracks and pores caused by excessively rapid cooling of the molten pool.

[0024] Step 3: Add an independent wire feeding mechanism on one side of the laser-GMAW composite welding gun in the forward direction. The independent wire feeding mechanism feeds aluminum alloy non-electric cold wire 6 that matches the composition of the main welding wire. The front end of the cold wire 6 is located in front of the molten pool and close to the edge of the molten pool. It is fed in synchronously with the main welding wire 3 during the additive manufacturing process. Step 4: Set the GMAW additive manufacturing process parameters, welding speed, laser power, laser defocusing amount and cold wire filling speed according to the forming characteristics of aluminum alloy, and ensure that each parameter is matched to achieve decoupling of energy and deposition rate; Step 5: Adjust the posture of the laser-GMAW composite welding gun, the wire feeding angle and position of the cold wire 6, and plan the additive manufacturing path; Step 6: Introduce a protective gas and adjust the flow rate; wherein the protective gas is high-purity argon with a purity ≥99.99%, and the flow rate is 20-25 L / min, covering the ends of the main welding wire and cold wire to reduce defects such as porosity and oxide inclusions.

[0025] Step 7: Start the laser-GMAW composite heat source and cold wire feeding mechanism to carry out the first layer deposition. After the deposition is completed, use vernier calipers to measure the first layer forming height at multiple points and take the average value as the offset of each layer in the additive manufacturing forming direction. Deposit layer by layer strictly according to the preset path. After each layer is deposited, perform surface cleaning until the additive manufacturing of aluminum alloy components is completed.

[0026] In the laser-GMAW composite heat source additive manufacturing process, the laser heat source and the GMAW arc heat source work synergistically, and the process parameters meet the following conditions: laser power is 400-600W, laser defocusing adjustment range is 0-2mm, laser is output in pulse mode with a frequency of 30-50Hz, and laser pulse width is 1-2.5ms. The GMAW power supply adopts DC reverse polarity mode, the wire feeding speed of the main welding wire 3 is 6-10m / min, the welding current is 150-210A, the welding voltage is 18-22V, and the welding speed is 8-12mm / s. The cold wire 6 is an aluminum alloy welding wire matched with the main welding wire 3, and the wire feeding speed of the cold wire 6 is 3-5m / min. The wire feeding speeds of the cold wire 6 and the main welding wire 3 are independently adjustable.

[0027] In particular, by synergistically matching the laser pulse parameters with the GMAW arc parameters, the arc energy density can be improved, the molten pool morphology can be stabilized, and spatter and porosity in the aluminum alloy additive manufacturing process can be suppressed, thus ensuring the stability and internal density of the weld formation.

[0028] The GMAW welding torch 4 is perpendicular to the surface of the aluminum alloy substrate 1, and the GMAW welding torch 4 and the laser torch head 5 are combined in a paraaxial manner. During the additive manufacturing process, the laser torch head 5 is in front and the GMAW welding torch 4 is behind. The angle between the axis of the GMAW welding torch 4 and the axis of the laser torch head 5 is 30°-45°. The cold wire 6 is independently fed in from the front of the laser-GMAW composite welding torch. The angle between the axis of the cold wire 6 and the surface of the substrate 1 is 20°-30°. The end of the cold wire 6 is precisely pointed to the front edge of the molten pool to ensure that the cold wire 6 enters the molten pool smoothly and is fully melted.

[0029] In this invention, the distance between the end of the main welding wire 3 of the GMAW and the laser filament is 0-1mm, ensuring the synergistic effect of the laser and the electric arc; the end of the cold wire 6 lightly touches the edge of the molten pool, the distance between the end of the cold wire 6 and the end of the main welding wire 3 is 0-2mm, and the distance between the end of the cold wire 6 and the surface of the substrate 1 is 0-1mm. This setting can avoid forming defects caused by the cold wire 6 not being fused or being over-inserted into the molten pool.

[0030] The method of the present invention will be further illustrated below through specific embodiments: This embodiment focuses on laser-GMAW cold wire co-additive manufacturing of 5183 aluminum alloy. The specific manufacturing method is as follows: 5083 aluminum alloy sheet was selected as the substrate. The substrate surface underwent pretreatment including degreasing, oxide film removal, and polishing. Anhydrous ethanol was used to wipe the substrate surface to remove oil stains, and then sandpaper was used to polish the surface oxide film and impurities to avoid forming defects caused by oxide inclusions. After pretreatment, a special fixture was used to fix the substrate on the work platform to ensure that the substrate was flat and not loose, preventing substrate displacement from affecting the forming accuracy during additive manufacturing.

[0031] The parameters for the laser-GMAW composite heat source are then set as follows: The laser power is 500W, defocusing amount is +1mm, pulse frequency is 50Hz, pulse width is 2ms, and the laser-GMAW main welding wire spacing is 1mm. The GMAW power supply adopts DC reverse polarity mode, welding current is 180A, welding voltage is 20V, and welding speed is set to 10mm / s. The GMAW main welding wire is a 1.2mm diameter 5183 aluminum alloy welding wire, and the cold wire is also a 1.2mm diameter 5183 aluminum alloy welding wire. The additive manufacturing process involves unidirectional deposition along a straight path, and the wire feeding posture and position are set as follows: The 5183 aluminum alloy main welding wire is fed perpendicularly to the substrate using a GMAW welding torch, while the 5183 aluminum alloy cold wire is fed forward from the front of the torch. The angle between the laser and the GMAW torch axis is 45°, and the angle between the cold wire and the substrate is 25°. The end of the cold wire is located at the edge of the molten pool and in close contact with the substrate surface. The GMAW main welding wire feed speed is 7 m / min, and the cold wire feed speed is 3 m / min. The main welding wire and cold wire feeds are controlled by independent systems, which can be flexibly adjusted according to deposition requirements, achieving decoupled control of energy input and material deposition rate.

[0032] The protective gas is high-purity argon with a purity of ≥99.99%, and the gas flow rate is adjusted to 25L / min.

[0033] The pretreated 5183 aluminum alloy substrate is preheated at 100℃ to reduce cracking defects caused by excessive temperature difference between the molten pool and the cold substrate. After preheating, the first layer is deposited. After deposition, three evenly distributed measurement points are selected on the first layer using vernier calipers to measure the deposition height and take the average value. The average value is 3mm, which is used as the Z-axis offset of each layer in the additive manufacturing forming direction. During interlayer deposition, thermocouples are used to monitor the interlayer temperature and strictly control it at 50℃ to avoid severe remelting and coarse grains caused by excessive interlayer temperature. Then, the layers are deposited layer by layer according to the preset straight path until the additive manufacturing of the 5183 aluminum alloy component is completed.

[0034] The above method was used for additive manufacturing of 5183 aluminum alloy components. The forming process was stable, with no obvious spatter or porosity defects. The forming efficiency of the additively manufactured structural parts was improved by more than 50% compared with the traditional laser-GMAW composite additive manufacturing process, and the forming effect was good. Specific forming effects are shown in the figure below. Figure 2 As shown in Figure 3, the metallographic structure of the formed component is a uniformly distributed equiaxed crystal structure.

[0035] The mechanical properties of the formed components were tested, and the test results are as follows: Figure 4As shown: the ultimate tensile strength of the component is 285.9 MPa in the transverse direction and 271.3 MPa in the longitudinal direction; the elongation after fracture in the transverse direction is 26.4% and the elongation after fracture in the longitudinal direction is 21.9%. It has excellent mechanical properties and meets the high-performance requirements of large 5183 aluminum alloy components in fields such as rail transit and shipbuilding.

[0036] All matters not covered in this invention are common knowledge.

[0037] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for laser-GMAW cold filament co-additive manufacturing of aluminum alloys, characterized in that: The method includes the following steps: Step 1: Select an aluminum alloy sheet with a composition similar to that of the welding wire as the substrate, pre-treat the surface of the substrate, and fix it on the work platform with a clamp to ensure that the substrate is flat and not loose. Step 2: Preheat the pretreated aluminum alloy substrate; Step 3: Add an independent wire feeding mechanism on one side of the laser-GMAW composite welding gun in the forward direction. The independent wire feeding mechanism feeds an aluminum alloy non-electric cold wire that matches the composition of the main welding wire. The front end of the cold wire is located in front of the molten pool and close to the edge of the molten pool. It is fed synchronously with the main welding wire during the additive manufacturing process. Step 4: Set the GMAW additive manufacturing process parameters, welding speed, laser power, laser defocusing amount and cold wire filling speed according to the forming characteristics of aluminum alloy, and ensure that each parameter is matched to achieve decoupling of energy and deposition rate; Step 5: Adjust the laser-GMAW composite welding torch posture, cold wire feeding angle and wire feeding position, and plan the additive manufacturing path; Step 6: Introduce protective gas and adjust the protective gas flow rate; Step 7: Start the laser-GMAW composite heat source and cold wire feeding mechanism to carry out the first layer deposition. After the deposition is completed, use vernier calipers to measure the first layer forming height at multiple points and take the average value as the offset of each layer in the additive manufacturing forming direction. Deposit layer by layer strictly according to the preset path. After each layer is deposited, perform surface cleaning until the additive manufacturing of aluminum alloy components is completed.

2. The method for laser-GMAW cold filament co-additive manufacturing of aluminum alloys according to claim 1, characterized in that: In the laser-GMAW composite heat source additive manufacturing process, the laser heat source and the GMAW arc heat source work together, and the process parameters meet the following conditions: the laser power is 400-600W, the laser defocusing amount is adjustable from 0 to 2mm, the laser is output in pulse mode with a frequency of 30-50Hz, and the laser pulse width is 1-2.5ms.

3. The method for laser-GMAW cold filament co-additive manufacturing of aluminum alloys according to claim 2, characterized in that: The GMAW uses a DC reverse polarity power supply, with a main wire feeding speed of 6-10 m / min, a welding current of 150-210 A, a welding voltage of 18-22 V, and a welding speed of 8-12 mm / s.

4. The method for laser-GMAW cold filament co-additive manufacturing of aluminum alloys according to claim 3, characterized in that: The cold wire is an aluminum alloy welding wire that matches the main welding wire. The cold wire feeding speed is 3-5 m / min, and the cold wire feeding speed and the main welding wire feeding speed can be adjusted independently.

5. The method for laser-GMAW cold filament co-additive manufacturing of aluminum alloys according to claim 1, characterized in that: The GMAW welding torch is perpendicular to the surface of the aluminum alloy substrate, and the GMAW welding torch and the laser torch head are combined in a paraaxial manner. During the additive manufacturing process, the laser torch head is in front and the GMAW welding torch is behind, with the GMAW welding torch axis and the laser torch head axis forming an angle of 30°-45°. The cold wire is independently fed from the front of the laser-GMAW composite welding torch, with the cold wire axis forming an angle of 20°-30° with the substrate surface. The end of the cold wire is precisely pointed to the front edge of the molten pool to ensure that the cold wire enters the molten pool smoothly and is fully melted.

6. The method for laser-GMAW cold filament co-additive manufacturing of aluminum alloys according to claim 1, characterized in that: The distance between the end of the main welding wire of the GMAW and the laser filament is 0-1mm to ensure the synergistic effect of the laser and the electric arc; the end of the cold wire lightly touches the edge of the molten pool, the distance between the end of the cold wire and the end of the main welding wire is 0-2mm, and the distance between the end of the cold wire and the surface of the substrate is 0-1mm.

7. The method for laser-GMAW cold filament co-additive manufacturing of aluminum alloys according to claim 1, characterized in that: The protective gas is high-purity argon with a purity of ≥99.99%, and the flow rate of the protective gas is 20-25 L / min, covering the ends of the main welding wire and the cold wire.

8. The method for laser-GMAW cold filament co-additive manufacturing of aluminum alloys according to claim 1, characterized in that: The preheating temperature of the aluminum alloy substrate is 80-120℃.

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