A hybrid laser additive manufacturing method

Abstract

The application provides a composite laser additive manufacturing method and system. The composite laser additive manufacturing method of the application comprises the following steps: S1, respectively pretreating a base material and metal powder; S2, vertically irradiating a blue laser on a surface of the base material to form a molten pool, obliquely irradiating an infrared laser on a rear end of the molten pool, and feeding the metal powder into the molten pool, so that the metal powder is melted in the molten pool and metallurgically combined with the base material to form an additive. The method of the application can smooth a solidification interface of a copper alloy, delay a solidification process, facilitate gas overflow in the molten pool, greatly inhibit the formation of pores, reduce the porosity of the formed copper alloy, effectively reduce defects such as pores, cracks and incomplete fusion, and realize efficient and high-quality forming of a copper alloy component.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, and in particular to a composite laser additive manufacturing method. Background Technology

[0002] Copper alloys, with their excellent thermal conductivity, electrical conductivity, ductility, and corrosion resistance, have irreplaceable application value in fields such as hot-end components of aerospace engines, heat dissipation components for electronic devices, and high-precision mechanical parts. Laser direct deposition additive manufacturing technology, as a new and advanced manufacturing technology, enables the integrated molding of complex copper alloy components without the need for complex molds, significantly shortening the production cycle and reducing manufacturing costs. It has become a core technology direction for the manufacturing of high-end copper alloy components.

[0003] However, copper alloys exhibit extremely high reflectivity to traditional single-wavelength infrared lasers (1064 nm), typically exceeding 90%. This results in low laser energy utilization, poor molten pool stability, and a predisposition to forming defects such as porosity, cracks, and incomplete fusion, severely impacting the forming quality and mechanical properties of copper alloy components. While single-wavelength blue lasers (450 nm) can reduce the reflectivity of copper alloys (absorption rate can reach 60-70%) and improve surface melting, they suffer from low power density, low forming efficiency, and insufficient penetration depth, making it difficult to meet the manufacturing requirements of thick-walled, large copper alloy components and limiting the large-scale application of laser additive manufacturing technology in the copper alloy field. Therefore, effectively controlling the molten pool in laser direct deposition additive manufacturing of copper alloys to suppress forming defects such as porosity, cracks, and incomplete fusion is a key issue in achieving high-quality copper alloy manufacturing through laser direct deposition additive manufacturing.

[0004] Currently, some existing technologies attempt to improve the laser additive manufacturing effect of copper alloys through powder surface modification and process parameter optimization, but they fail to fundamentally solve the inherent defects of a single laser source, resulting in problems such as difficulty in balancing energy utilization and forming efficiency, unstable forming quality, and uneven component performance. Furthermore, most existing composite laser technologies focus on joining dissimilar metals or preparing surface coatings, and suffer from poor synergy between composite lasers, unreasonable parameter matching, and insufficient compatibility between powders and composite lasers, making it impossible to achieve efficient and high-quality forming of copper alloy components.

[0005] Therefore, developing a method that can achieve synergistic effects of red and blue lasers, balance energy utilization, forming efficiency and forming quality, and is compatible with copper alloy additive manufacturing, in order to solve the above-mentioned technical problems in the existing technology, has important technical value and industrialization prospects. Summary of the Invention

[0006] The purpose of this invention is to provide a composite laser additive manufacturing method that can improve the stability and forming efficiency of the molten pool, suppress forming defects such as porosity, cracks and lack of fusion, and facilitate the efficient and high-quality laser direct deposition additive manufacturing of copper alloy components.

[0007] This invention provides a composite laser additive manufacturing method, comprising the following steps: S1: Pre-treat the substrate and metal powder separately; S2: A blue laser is vertically irradiated onto the surface of the substrate to form a molten pool, and an infrared laser is tilted to irradiate the rear edge of the molten pool. Metal powder is fed into the molten pool, where it melts and metallurgically bonds with the substrate to form an additive material.

[0008] In this invention, the substrate material can be SS316L stainless steel, pure copper, alloy materials, etc.; the substrate can be a substrate with a thickness of... 12 mm. Pretreatment of the substrate includes: grinding, sanding, ultrasonic cleaning, and organic solvent removal, followed by drying; the organic solvent can be alcohol, acetone, etc. The pretreated substrate can be placed on a processing table and secured with clamps for subsequent processing.

[0009] The metal powder can be made of copper alloys, such as Cu-Cr-Zr series copper alloys, especially GRCop 42 alloy; the particle size of the metal powder is 53-127 μm, the sphericity is ≥95%, and the tap density is 5.2×10⁻⁶. 3 kg / m 3 -5.8×10 3 kg / m 3 Pretreatment of metal powder includes: placing the metal powder in... Dry at 100 ℃ for more than 2 hours to remove water vapor and other impurities adhering to the surface of the metal powder and increase the fluidity of the metal powder material.

[0010] In this invention, a blue laser is output from a blue laser generator and vertically irradiates the substrate surface through a cladding head. The blue laser has a circular spot with a flat top distribution, and the spot diameter is 0.5-10 mm, preferably 2.0-5.0 mm, and more preferably 4.0-5.0 mm. The wavelength of the blue laser is 480-532 nm. The power of the blue laser is 500-5000 W, preferably 1500-3500 W, and more preferably 2700-3000 W. The defocusing amount of the blue laser is -5 mm to +5 mm, preferably -3 mm to +4 mm. The operating mode is continuous emission mode. Vertical irradiation of the substrate surface by the blue laser is beneficial for utilizing its high energy absorption rate and other advantages to quickly melt the substrate surface and form a shallow molten pool.

[0011] Infrared laser light can be output through an infrared laser generator, and the tilting angle of the irradiation can be adjusted by the welding head. The infrared laser is a circular spot with a Gaussian energy distribution, and the spot diameter is 0.6-0.8 times that of the blue laser spot, preferably 0.6-0.7 times. The wavelength of the infrared laser is 1060-1070 nm. The power of the infrared laser is 500-5000 W, preferably 1000-3500 W, and more preferably 1200-1900 W. The infrared laser operates in pulsed emission mode, with a pulse frequency of 10-5000 Hz, preferably 50-200 Hz, and more preferably 90-150 Hz. The infrared laser is tilted and irradiated at the trailing edge of the molten pool, and the angle α between the infrared laser beam and the blue laser beam (i.e., the tilting angle of the infrared laser) is 10°. -80 Preferably 35 -65 .

[0012] In this invention, oblique irradiation of the infrared laser at the trailing edge of the molten pool means that the centerline of the infrared laser beam is located 0.5-1.5 mm behind the centerline of the blue laser beam, with the infrared laser spot partially overlapping the blue laser spot, the overlapping portion accounting for 30-40% of the infrared laser spot. By obliquely irradiating the trailing edge of the molten pool with the infrared laser, the energy of the oblique incident beam is used to delay the solidification process at the trailing edge, thus increasing the solidification time of the molten pool. This facilitates the escape of gases precipitated in the liquid metal from the molten pool, reducing porosity in the solidified structure and minimizing cracks and incomplete fusion defects. The combination of vertical irradiation with blue laser and oblique irradiation with infrared laser from the rear maximizes the advantages of blue laser in rapidly forming a shallow molten pool and pulsed infrared laser in increasing the solidification time and controlling the solidification structure.

[0013] Furthermore, the included angle α is determined according to the following formula:

[0014] in: The height of the molten pool The radius of the blue laser spot. The radius of the infrared laser spot. This refers to the laser scanning speed.

[0015] By accurately determining the included angle α using the above formula, the incident angle of the infrared laser can be made closer to the tilt angle of the solidification interface of the molten pool. This maximizes the absorption rate of the infrared laser and optimizes the refining effect of the pulse frequency modulation of the infrared laser on the solidified structure of the molten pool.

[0016] In this invention, the laser scanning speed is 1-20 mm / s (i.e., the scanning speed of both the blue laser and the infrared laser is 1-20 mm / s), preferably 8-16 mm / s, and more preferably 8-12 mm / s; the powder feeding rate of the metal powder is 3-20 g / min, preferably 9-18 g / min.

[0017] In the aforementioned composite laser additive manufacturing process, a protective gas (e.g., high purity) can be used. The entire process is protected by 99.99% high-purity argon gas. In addition, a side-viewing infrared camera can be used to monitor the morphology and fluctuation behavior of the molten pool in real time, and the blue laser and infrared laser process parameters can be adjusted in real time according to the morphology and fluctuation of the molten pool to ensure that the infrared laser tilt angle α is close to the tilt angle of the molten pool solidification interface until the manufacturing process is completed.

[0018] The present invention also provides a composite laser additive manufacturing system, comprising: A processing table, used to fix the substrate; A composite laser forming apparatus includes a blue laser generator for outputting blue laser, a cladding head for vertically irradiating the substrate surface with blue laser, an infrared laser generator for outputting infrared laser, and a welding head for adjusting the tilt angle of the infrared laser irradiation. A powder feeding device is used to feed metal powder into the molten pool; A protective gas device is used to create a protective gas atmosphere in the molten pool area.

[0019] Compared with the prior art, the present invention has at least the following advantages: 1. Addressing core pain points in copper alloy laser additive manufacturing, such as high reflectivity, low energy utilization, and poor forming quality: A synergistic red-blue composite laser is employed. The blue laser is vertically irradiated onto the substrate surface to form a molten pool. Utilizing its low reflectivity to copper alloys, the blue laser enhances the preheating effect of the metal powder and the stability of the molten pool. Simultaneously, an infrared laser is obliquely irradiated along the trailing edge of the molten pool, while the red laser, with its high thermal effect, forms a keyhole in the molten pool, increasing the melting depth. The synergistic effect of the red and blue lasers optimizes energy distribution, increasing the absorption rate of the laser in the molten pool from below 30% with a single red laser to over 70%, significantly improving laser energy utilization and reducing energy waste. In particular, the synergistic effect of the blue and infrared lasers smooths the solidification interface of the copper alloy, slows down the solidification process, facilitates gas escape from the molten pool, greatly inhibits the formation of pores, and reduces the porosity of the formed copper alloy.

[0020] 2. Balancing forming efficiency and quality while reducing forming defects: By optimizing the red-blue laser power ratio, scanning strategy, and process parameters (especially the pulse frequency of the infrared laser, the spot radius of the blue laser, and the tilt angle α of the infrared laser), the morphology and solidification behavior of the copper alloy molten pool are precisely controlled. Blue light dominates the melting of the substrate, refines the grains, and improves surface precision, while red light dominates the increase in melting depth and improves forming efficiency. The blue-infrared composite laser effectively reduces defects such as porosity, cracks, and incomplete fusion, achieving a forming density of over 99.3% and a crack density ≤0.1 mm. 2 The forming efficiency is more than 40% higher than that of single blue laser additive manufacturing and more than 20% higher than that of single red laser additive manufacturing. 3. Wide adaptability and strong practicality: It can prepare copper alloy components with different compositions and performance requirements, and is suitable for the manufacturing of components under harsh working conditions such as hot-end components of aerospace engines, heat dissipation components of electronic equipment, and high-end precision mechanical parts; the composite laser additive manufacturing method is compatible with existing laser additive manufacturing equipment, and can be upgraded through modular transformation, which is convenient for promotion and application, and has good industrialization prospects and application value. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific 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 from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the composite laser additive manufacturing system of the present invention; Figure 2 Laser confocal microscope image of the surface quality of the copper alloy prepared in Example 1; Figure 3 Laser confocal microscope image of the surface quality of the copper alloy prepared in Example 2; Figure 4 Laser confocal microscope image of the surface quality of the copper alloy prepared in Example 3; Figure 5 Laser confocal microscope image of the surface quality of the copper alloy prepared in Comparative Example 1; Figure 6 Laser confocal microscope image of the surface quality of the copper alloy prepared in Comparative Example 2; Figure 7 Laser confocal microscope image of the surface quality of the copper alloy prepared in Comparative Example 3; Figure 8 An optical microscope image of the internal defects of the copper alloy prepared in Example 1; Figure 9 An optical microscope image of the internal defects of the copper alloy prepared in Example 2; Figure 10 An optical microscope image of the internal defects of the copper alloy prepared in Example 3; Figure 11 An optical microscope image of the internal defects of the copper alloy prepared in Comparative Example 1; Figure 12 An optical microscope image of the internal defects of the copper alloy prepared in Comparative Example 2; Figure 13 An optical microscope image of the internal defects of the copper alloy prepared in Comparative Example 3; Figure 14 This is a grain distribution diagram of the copper alloy prepared in Example 1; Figure 15 This is a grain distribution diagram of the copper alloy prepared in Example 2; Figure 16 This is a grain distribution diagram of the copper alloy prepared in Example 3; Figure 17 The grain distribution diagram is shown for the copper alloy prepared in Comparative Example 1. Figure 18 The grain distribution diagram is shown for the copper alloy prepared in Comparative Example 2. Figure 19 The grain distribution diagram is for the copper alloy prepared in Comparative Example 3.

[0023] Explanation of reference numerals in the attached figures: 1: Substrate; 2: Blue laser; 3: Cladding head; 4: Infrared laser; 5: Welding head; 6: Metal powder; 7: Molten pool. Detailed Implementation

[0024] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0025] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the 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.

[0027] Example 1 The composite laser additive manufacturing method of this embodiment includes the following steps: 1. Laser parameter settings The blue laser has a wavelength of 480 nm, a spot diameter of 4.8 mm, a power of 2800 W, a defocusing amount of -2 mm, and operates in continuous emission mode.

[0028] The infrared laser spot diameter is 0.7 times that of the blue laser spot diameter; the infrared laser wavelength is 1064 nm, the power is 1700 W, the working mode is pulsed light output mode, and the pulse frequency is 100 Hz.

[0029] The tilt angle α of the infrared laser is determined according to the following formula:

[0030] in: This represents the height of the molten pool, specifically 1.75. The radius of the blue laser spot is 4.1 mm. The radius of the infrared laser spot is 3.0 mm. The laser scanning speed is 10 mm / s; the tilt angle α of the infrared laser is calculated to be 53° using the above formula.

[0031] 2. Material pretreatment The substrate is made of pure copper and is 12 mm thick. The surface of the substrate is ground, sanded, ultrasonically cleaned, and oil and oxides are removed with alcohol. After the surface is dried, it is placed on the processing table and secured with clamps for subsequent processing.

[0032] The metal powder is made of GRCop 42 alloy, with an average particle size of 78 μm, a sphericity of 95%, and a tap density of 5.4 × 10⁻⁶. 3 kg / m 3 The metal powder was dried at 100 °C for 4 h to remove impurities such as water vapor adhering to the surface of the metal powder and to increase the flowability of the metal powder material.

[0033] 3. Composite laser processing Check the coaxiality of the blue laser spot and the metal powder, observe the stability and convergence of the metal powder flow, and ensure that the blue laser beam and the metal powder flow can be coaxially and confocally converged on the surface of the substrate to be processed.

[0034] Adjust the orientation of the blue laser cladding head to keep it vertically downward; adjust the orientation of the infrared laser welding head to ensure that the infrared laser is tilted at a 53° angle to the trailing edge of the molten pool (the center line of the infrared laser beam is located approximately 1 mm behind the center line of the blue laser beam, with the infrared laser spot partially overlapping the blue laser spot, the overlap occupying about one-third of the infrared laser spot). Load the metal powder into the powder feeding device, using argon as the carrier gas (purity...). (99.99%), the metal powder is fed into the cladding head.

[0035] Using the aforementioned laser parameters, a blue laser is perpendicularly irradiated onto the substrate surface through a cladding head to form a micro-molten pool, while an infrared laser is obliquely irradiated onto the surface of the molten pool. Metal powder is then gathered through the cladding head and fed into the molten pool at a powder feeding rate of 18 g / min. Argon is used as the protective gas (purity...). The entire process is protected (99.99%). A side-viewing infrared camera is used to monitor the morphology and fluctuation behavior of the molten pool in real time. The blue laser and infrared laser process parameters are adjusted in real time according to the morphology and fluctuation of the molten pool, so that the infrared laser tilt angle α is close to the tilt angle of the molten pool solidification interface until the manufacturing process is completed.

[0036] The aforementioned composite laser additive manufacturing method can be performed using a composite laser additive manufacturing system; combined with Figure 1 As shown, the composite laser additive manufacturing system includes a processing table, a composite laser forming device, a powder feeding device, and a protective gas device. The processing table is used to fix the substrate 1. The composite laser forming device includes a blue laser generator for outputting blue laser 2, a cladding head 3 for vertically irradiating the surface of the substrate 1 with blue laser 2, an infrared laser generator for outputting infrared laser 4, and a welding head 5 for adjusting the tilt angle of the infrared laser 4. The powder feeding device is used to feed metal powder 6 into the molten pool 7. The protective gas device is used to form a protective gas atmosphere in the area of ​​the molten pool 7.

[0037] The surface quality laser confocal microscope image, internal defect optical microscope image, and grain distribution map of the copper alloy prepared in this embodiment are shown in the following figures. Figure 2 , Figure 8 , Figure 14 .Depend on Figure 2 It is evident that the prepared copper alloy has a smooth surface with only a small amount of adhered unmelted powder particles, indicating high surface quality; Figure 8 It is evident that the prepared copper alloy has almost no internal pores, low porosity, and a density exceeding 99%. No obvious defects such as unfused voids or cracks were observed. Figure 14It can be seen that the average grain size of the prepared copper alloy is 138 micrometers.

[0038] In addition, the solidification time of the copper alloy was detected using an ultra-high-speed camera, and the mechanical properties were tested using a universal tensile testing machine. The results are shown in Table 1.

[0039] Example 2 Except for the following process parameters, the rest are the same as in Example 1.

[0040] The process parameters for this embodiment are as follows: The blue laser has a wavelength of 480 nm, a spot diameter of 4.8 mm, a power of 3000 W, a defocusing amount of -3 mm, and operates in continuous emission mode.

[0041] The infrared laser spot diameter is 0.7 times that of the blue laser spot diameter; the infrared laser wavelength is 1064 nm, the power is 1900 W, the working mode is pulsed light output mode, and the pulse frequency is 90 Hz.

[0042] The tilt angle α of the infrared laser is determined according to the following formula:

[0043] in: This represents the height of the molten pool, specifically 1.75. This represents the spot radius of the blue laser, specifically 3.5 mm. The radius of the infrared laser spot is 3 mm. The laser scanning speed is 10 mm / s; the tilt angle α of the infrared laser is calculated to be 35° using the above formula.

[0044] The surface quality laser confocal microscope image, internal defect optical microscope image, and grain distribution map of the copper alloy prepared in this embodiment are shown in the following figures. Figure 3 , Figure 9 , Figure 15 The results showed that the prepared copper alloy had a relatively smooth surface with only a small amount of adhering unmelted powder particles, indicating a high surface quality. The prepared copper alloy had only pores inside, with low porosity and a density of 95%. No obvious defects such as unfused pores or cracks were observed. The average grain size of the prepared copper alloy was 178 micrometers.

[0045] Example 3 Except for the following process parameters, the rest are the same as in Example 1.

[0046] The process parameters for this embodiment are as follows: The blue laser has a wavelength of 480 nm, a spot diameter of 4.8 mm, a power of 2700 W, a blue laser defocusing amount of +4 mm, and operates in continuous emission mode.

[0047] The infrared laser spot diameter is 0.6 times that of the blue laser spot diameter; the infrared laser wavelength is 1064 nm, the power is 1200 W, the working mode is pulsed light output mode, and the pulse frequency is 150 Hz.

[0048] The tilt angle α of the infrared laser is determined according to the following formula:

[0049] in: This represents the height of the molten pool, specifically 1.7. The radius of the blue laser spot is 4.2 mm. The radius of the infrared laser spot is 3.2 mm. The laser scanning speed is 10 mm / s; the tilt angle α of the infrared laser is calculated to be 65° using the above formula.

[0050] The surface quality laser confocal microscope image, internal defect optical microscope image, and grain distribution map of the copper alloy prepared in this embodiment are shown in the following figures. Figure 4 , Figure 10 , Figure 16 The results showed that the prepared copper alloy had a smooth surface with only a small amount of adhered unmelted powder particles, indicating high surface quality. The prepared copper alloy had only a small amount of pores and low porosity, with a density of over 97%. No obvious defects such as unfused pores or cracks were observed. The average grain size of the prepared copper alloy was 156 micrometers.

[0051] Compare with Example 1 This comparative example is identical to Example 1, except that it uses a single infrared laser for processing.

[0052] The infrared laser parameters of this comparative example are as follows: the infrared laser spot diameter is 3.8 mm, the infrared laser wavelength is 1064 nm, the power is 3000 W, and the working mode is continuous emission mode; the infrared laser is perpendicularly irradiated on the substrate surface to form a molten pool (i.e., α is 0°).

[0053] The surface quality images of the copper alloy prepared in this comparative example, obtained using laser confocal microscopy, optical microscopy, and grain distribution diagrams, are shown below. Figure 5 , Figure 11 , Figure 17 .Depend on Figure 5 It is evident that the prepared copper alloy has an uneven surface, with a large amount of unmelted powder material adhering to it, resulting in low surface quality; Figure 11 It is evident that the prepared copper alloy contains numerous pores, exhibiting high porosity and a density of 93%, and large-sized cracks and other defects can be observed. Figure 17 It can be seen that the average grain size in the prepared copper alloy is 216 micrometers.

[0054] Compare with Example 2 Except that the infrared laser and the blue laser are coaxially and perpendicularly irradiated on the substrate surface (i.e., α is 0°), the rest is the same as in Example 1.

[0055] The surface quality images of the copper alloy prepared in this comparative example, obtained using laser confocal microscopy, optical microscopy, and grain distribution diagrams, are shown below. Figure 6 , Figure 12 , Figure 18 .Depend on Figure 6 It is evident that the prepared copper alloy has an uneven surface, with a large amount of unmelted powder material adhering to it, resulting in low surface quality; Figure 12 It is evident that the prepared copper alloy contains pores, has high porosity, and a density of 94%, with large-sized cracks and other defects also visible. Figure 18 It can be seen that the average grain size in the prepared copper alloy is 278 micrometers, which is due to the long solidification time in the deeper molten pool, resulting in coarse grain growth.

[0056] Compare with Example 3 Except for vertically irradiating the substrate surface with an infrared laser to form a molten pool and tilting the blue laser to irradiate the trailing edge of the molten pool (i.e., exchanging the positions of the blue laser and the infrared laser), the rest is the same as in Example 1.

[0057] The surface quality images of the copper alloy prepared in this comparative example, obtained using laser confocal microscopy, optical microscopy, and grain distribution diagrams, are shown below. Figure 7 , Figure 13 , Figure 19 .Depend on Figure 7 It is evident that the prepared copper alloy has an uneven surface, with a large amount of unmelted powder material adhering to it, resulting in low surface quality; Figure 13 It is evident that the prepared copper alloy contains pores, has high porosity, and a density of 93%, with large-sized cracks and other defects also visible. Figure 19 It can be seen that the average grain size in the prepared copper alloy is 234 micrometers.

[0058] Table 1 Solidification time and mechanical properties of copper alloys

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite laser additive manufacturing method, characterized in that, Includes the following steps: S1: Pre-treat the substrate and metal powder separately; S2: A blue laser is vertically irradiated onto the surface of the substrate to form a molten pool, and an infrared laser is tilted to irradiate the rear edge of the molten pool. Metal powder is fed into the molten pool, where it melts and metallurgically bonds with the substrate to form an additive material.

2. The composite laser additive manufacturing method according to claim 1, characterized in that, The blue laser spot diameter is 0.5-10 mm; the blue laser wavelength is 480-532 nm, the power is 500-5000 W, and the working mode is continuous emission mode.

3. The composite laser additive manufacturing method according to claim 1, characterized in that, The beam diameter of an infrared laser is 0.6-0.8 times that of a blue laser beam; the wavelength of an infrared laser is 1060-1070 nm, the power is 500-5000 W, the operating mode is pulsed emission mode, and the pulse frequency is 10-5000 Hz.

4. The composite laser additive manufacturing method according to claim 1, characterized in that, The angle α between the infrared laser beam and the blue laser beam is 10°. -80 .

5. The composite laser additive manufacturing method according to claim 4, characterized in that, The included angle α is determined using the following formula: in: The height of the molten pool The radius of the blue laser spot. The radius of the infrared laser spot. This refers to the laser scanning speed.

6. The composite laser additive manufacturing method according to claim 1, characterized in that, The laser scanning speed is 1-20 mm / s, and the powder feeding rate of the metal powder is 3-20 g / min.

7. The composite laser additive manufacturing method according to claim 1, characterized in that, Pretreatment of the substrate includes: grinding, sanding, ultrasonic cleaning, and organic solvent removal of the substrate surface, followed by drying.

8. The composite laser additive manufacturing method according to claim 1, characterized in that, Pretreatment of metal powder includes: placing the metal powder in... Dry at 100 ℃ for more than 2 hours.

9. The composite laser additive manufacturing method according to claim 1, characterized in that, The metal powder used is copper alloy powder; the particle size of the metal powder is 53-127 μm, the sphericity is ≥95%, and the tap density is 5.2×10⁻⁶. 3 kg / m 3 -5.8×10 3 kg / m 3 .

10. A composite laser additive manufacturing system, characterized in that, include: A processing table, used to fix the substrate; A composite laser forming apparatus includes a blue laser generator for outputting blue laser, a cladding head for vertically irradiating the substrate surface with blue laser, an infrared laser generator for outputting infrared laser, and a welding head for adjusting the tilt angle of the infrared laser irradiation. A powder feeding device is used to feed metal powder into the molten pool; A protective gas device is used to create a protective gas atmosphere in the molten pool area.

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