Efficient brazing method based on laser marking technology

Abstract

The invention relates to the technical field of metal brazing, in particular to an efficient brazing method based on a laser marking technology. The laser marking technology is adopted for regulating and controlling the metallurgical micro-area on the surface of the base metal, the formation of a micro-metallurgical structure is induced on the surface of the base metal by controlling the laser power and pattern design, the wettability and atomic diffusivity of the interface between the brazing filler metal and the base metal can be improved through the structure, the interface metallurgical reaction is promoted in the metal brazing process, and the metal brazing quality is improved. And wetting and spreading of brazing filler metal are promoted while the brazing connection area is increased, and then the mechanical property of a metal brazing joint is improved. In addition, according to the brazing method, the metallurgical bonding process is accelerated, the heat preservation time of a traditional brazing process is shortened, and therefore the production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal brazing, and more particularly to a high-efficiency brazing method based on laser marking technology. Background Art

[0002] Brazing is an important technical means in the process of joining high-temperature alloys. Due to its low welding temperature, it has little effect on the parent material and can effectively eliminate defects such as thermal cracks and pores in the process of joining high-temperature alloys. It is widely used in aerospace, electronic packaging and automobile manufacturing. However, in actual production, it has the following difficulties: (1) Low interface metallurgical reaction efficiency: During the bonding process between the brazing filler metal and the parent material, the diffusion rate of the interface reaction area is slow, resulting in poor bonding quality and low welding efficiency; (2) Insufficient joint mechanical properties: Due to the uneven interface structure during the brazing process, a large amount of brittle intermetallic compounds are generated, which significantly reduces the tensile strength and fatigue life of the joint; (3) Long process time: Traditional brazing technology requires a long holding time to ensure sufficient interface metallurgical bonding, which affects production efficiency.

[0003] Based on the above problems, some researchers have optimized the brazing filler metal composition and brazing parameters used in brazing technology to improve the brazing effect. For example, Chinese invention patent CN119634867A discloses a brazing connection method for tungsten alloy and molybdenum alloy, which adds Cu, Cr and Zr elements to the conventional Ni-Ti brazing filler metal. At the same time, a metal foam nickel intermediate layer is added during the brazing process to absorb residual strain energy, refine and divert the brazing filler metal, thereby improving the plastic toughness and mechanical properties of the joint. Some researchers have also improved the mechanical properties of brazed joints by depositing or embedding modified coatings on the parent material. For example, Chinese invention patent CN119977614A forms a SiC-MoSi2 composite coating on the surface of the carbon / carbon composite material by embedding a SiC coating and spraying a Mo-Si coating in a carbon / carbon composite material in sequence, and curing it through high-temperature heat treatment. The presence of the SiC-MoSi2 composite coating improves the wettability and interfacial bonding strength between the brazing filler metal and the parent material, thereby making the brazed connection stronger and more stable.

[0004] However, current improvement methods involve the optimization of new material components or the construction of new coatings, which further complicates the welding process and requires a long holding time to ensure sufficient metallurgical bonding at the interface, seriously affecting production efficiency.

[0005] Therefore, it is of great significance to provide an efficient brazing method to solve the brazing efficiency and performance problems from the perspective of metallurgical micro-area regulation on the base material surface without depositing a modified coating on the base material. Summary of the Invention

[0006] To achieve the above objectives, the present invention provides an efficient brazing method based on laser marking technology. The present invention uses laser marking technology to regulate the metallurgical micro-areas on the surface of the parent material. By controlling the laser power and pattern design, the formation of a microscopic metallurgical structure is induced on the surface of the parent material. This structure can improve the wettability and atomic diffusion capacity of the interface between the solder and the parent material, promote the interfacial metallurgical reaction during the metal brazing process, increase the brazing connection area, and promote the wetting and spreading of the solder, thereby improving the mechanical properties of the metal brazing joint. In addition, the brazing method of the present invention accelerates the metallurgical bonding process, reduces the holding time of the traditional brazing process, and thus improves production efficiency.

[0007] To achieve the above object, the present invention provides the following technical solutions: An efficient brazing method based on laser marking technology comprises the following steps: Step 1: Use the laser marking system to fix the base material to be brazed, adjust the distance between the laser lens and the base material to be brazed, and adjust the laser marking system parameters; Step 2: Add a light-transmitting confinement layer on the surface of the base material to be brazed that can accommodate the vertical propagation of high-amplitude plasma shock waves; Step 3: Use laser marking software to design different marking patterns and marking areas; turn on the laser to mark the base material to be brazed, and the laser induces plastic deformation on the base material surface to form metallurgical micro-areas; Step 4: Assemble the laser-marked base material and the brazing filler metal so that they are aligned with the surfaces to be welded, ensuring that the brazing filler metal evenly covers the welding interface, and then place them in a vacuum brazing furnace for welding.

[0008] Furthermore, in step 1, the distance between the laser lens and the base material to be brazed is the focal length of the lens.

[0009] Furthermore, the parameters of the laser marking system in step 1 are: laser power density: 2.5GW / cm²~4.5GW / cm²; pulse duration: 10ns~50ns; marking depth: 0.5μm~1.5μm; surface roughness optimization range: Ra=0.5μm~1.2μm.

[0010] Furthermore, the base material to be brazed in step 1 includes but is not limited to titanium alloy, stainless steel, niobium alloy, single crystal alloy and nickel-based alloy.

[0011] Furthermore, the constrained layer in step 2 is a flowing deionized water layer.

[0012] Furthermore, the marking pattern in step 3 includes but is not limited to honeycomb, periodic dot matrix or radial stripes.

[0013] Furthermore, during the laser marking process of the base material to be brazed in step 3, the marking area is covered by a constraint layer, and the laser cannot directly act on the surface of the base material to be brazed.

[0014] Furthermore, during the laser marking process in step 3, the energy density of the laser is changed by adjusting the laser spot size and laser energy, thereby controlling the degree of plastic deformation induced by the laser on the surface of the base material.

[0015] Furthermore, the metallurgical micro-regions in step 3 include nano-grains, high-density grain boundaries and high residual compressive stress regions.

[0016] Furthermore, in step 4, the brazing temperature is within 10°C to 20°C above the melting point of the brazing material, and the holding time is 2 to 3 minutes. These brazing process parameters can effectively suppress the formation of brittle compounds at the interface.

[0017] The technical solution provided by the present invention has at least the following beneficial effects compared to the prior art: 1. The present invention does not require the introduction of a new coating on the surface of the base material. The metallurgical micro-area on the surface of the base material is regulated by laser marking technology. By controlling the laser power and pattern design, the formation of a microscopic metallurgical structure is induced on the surface of the base material. This structure can significantly increase the surface atomic diffusion channels and activation sites, improve the wettability and atomic diffusion capacity of the interface between the solder and the base material, promote the interfacial metallurgical reaction during the metal brazing process, increase the brazing connection area, and promote the wetting and spreading of the solder, thereby improving the mechanical properties of the metal brazing joint.

[0018] 2. The present invention forms high-density grain boundaries and compressive stress distribution on the surface of the base material through laser marking, thereby suppressing the excessive generation of brittle compounds during brazing and optimizing the interface structure and performance.

[0019] 3. The brazing method of the present invention accelerates the metallurgical bonding process, reduces the holding time of the traditional brazing process, and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The microstructure diagram and marking pattern of the brazing joint prepared by the brazing method of Example 1 of the present invention; wherein Figure 1 a is the microstructure of the brazed joint, Figure 1 b is the marking pattern ( Figure 1 (b) The left side shows the macroscopic morphology of the printed pattern, and the right side shows the white light interference contour of the printed pattern); Figure 2 The microstructure diagram of the brazing joint prepared by the brazing method of Example 2 of the present invention ( Figure 2 Left side) and the printed pattern diagram ( Figure 2 right); Figure 3The microstructure diagram, printed pattern diagram and solder wetting structure diagram of the brazed joint prepared by the brazing method of Example 3 of the present invention are shown in FIG. Figure 3 a is the microstructure diagram of the brazed joint. Figure 3 b is a schematic diagram of the marking pattern. Figure 3 c is the solder wetting structure diagram. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to more clearly understand the application, the present invention is further described in detail below in conjunction with Examples and accompanying drawings, but it should be understood that the following examples are only preferred embodiments of the present invention, and the scope of protection claimed in the present invention should be based on the scope limited by the claims. In the description of the present invention, it should be noted that, in the examples, specific conditions are not indicated, and the conditions recommended by normal conditions or manufacturers are carried out. Reagents used or instruments are not indicated by manufacturers, and are conventional products that can be obtained by commercial purchase.

[0022] In addition, in order to better illustrate the present invention, numerous specific details are provided in the specific embodiments below. It should be understood by those skilled in the art that the present invention can also be implemented without certain specific details. In some embodiments, raw materials, methods, means, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present invention.

[0023] Example 1

[0024] An efficient brazing method for GH536 high-temperature alloy and Nb521 niobium alloy based on laser marking technology comprises the following steps: Step 1. Use a laser marking system to fix the GH536 high-temperature alloy. Adjust the distance between the laser lens and the GH536 high-temperature alloy to the lens focal length. The laser marking system parameters are set as follows: laser power density: 2.5GW / cm², pulse duration: 15ns; marking depth: 0.8μm; surface roughness optimization range: Ra = 0.7μm. Step 2: Adding a light-transmitting confinement layer on the surface of the GH536 high-temperature alloy that can accommodate the vertical propagation of high-amplitude plasma shock waves; the confinement layer is a flowing deionized water layer; Step 3. Use laser marking software to design the marking area and marking pattern. The marking area is the area covered by the constrained layer, and the marking pattern is the number "1" (radial stripes). Turn on the laser to mark the GH536 high-temperature alloy. The laser induces plastic deformation on the surface of the GH536 high-temperature alloy. By adjusting the laser spot size and laser energy, the laser energy density is changed to control the degree of laser-induced plastic deformation on the surface of the GH536 high-temperature alloy, forming a metallurgical micro-region. The metallurgical micro-region includes nano-grains, high-density grain boundaries, and high residual compressive stress areas. Repeat steps 1 to 3 to perform the same laser marking on the Nb521 niobium alloy. Step 4: Assemble the laser-marked GH536 high-temperature alloy, Nb521 niobium alloy, and Ti-based brazing filler metal (TiZrCuNi) to the correct weld surfaces. Place the components in a vacuum brazing furnace for brazing at a temperature of 1030°C for 3 minutes.

[0025] The microstructure and marking pattern of the brazed joint prepared by the brazing method of this embodiment are as follows: Figure 1 As shown. Among them, Figure 1 a is the microstructure of the brazed joint, Figure 1 b is the marking pattern ( Figure 1 b The left side is the macroscopic morphology of the printed pattern, and the right side is the white light interference contour diagram of the printed pattern). Figure 1 It can be seen that the brazing method of this embodiment obtains a structured surface with complete structure and uniform organization.

[0026] Example 2

[0027] This embodiment provides an efficient brazing method for stainless steel and TC4 titanium alloy based on laser marking technology, comprising the following steps: Step 1. Use a laser marking system to fix the stainless steel and adjust the distance between the laser lens and the stainless steel to the lens focal length. The laser marking system parameters are set as follows: laser power density: 4GW / cm², pulse duration: 30ns; marking depth: 1.2μm; surface roughness optimization range: Ra = 0.9μm; Step 2: Adding a light-transmitting confinement layer on the stainless steel surface that can accommodate the vertical propagation of high-amplitude plasma shock waves; the confinement layer is a flowing deionized water layer; Step 3. Use laser marking software to design the marking area and marking pattern. The marking area is the area covered by the constraint layer, and the marking pattern is 5 triangles arranged in a dot matrix. Turn on the laser to mark the stainless steel. The laser induces plastic deformation on the surface of the stainless steel. By adjusting the laser spot size and laser energy, the energy density of the laser is changed to control the degree of laser-induced plastic deformation on the stainless steel surface, thereby forming a metallurgical micro-region. The metallurgical micro-region includes nano-grains, high-density grain boundaries and high residual compressive stress areas. Repeat steps 1 to 3 to perform the same laser marking on the TC4 titanium alloy. Step 4: Assemble the laser-marked stainless steel, TC4 titanium alloy, and silver-based brazing filler metal to the correct weld surfaces, then place them in a vacuum brazing furnace for welding. The brazing temperature is 890°C, and the holding time is 2 minutes.

[0028] The microstructure and marking pattern of the brazed joint prepared by the brazing method of this embodiment are as follows: Figure 2 As shown. Among them, Figure 2 The left side shows the microstructure of the brazed joint. Figure 2 The right side is a schematic diagram of the marking pattern. Figure 2 It can be seen that the brazing method of this embodiment obtains a brazed joint with uniform structure and no defects.

[0029] Example 3

[0030] This embodiment provides an efficient brazing method for DD5 single crystal alloy and GH4169 nickel-based alloy based on laser marking technology, comprising the following steps: Step 1. Use a laser marking system to fix the DD5 single crystal alloy and adjust the distance between the laser lens and the DD5 single crystal alloy to the lens focal length. The laser marking system parameters are set as follows: laser power density: 4GW / cm², pulse duration: 25ns; marking depth: 1.2μm; surface roughness optimization range: Ra = 0.8μm; Step 2: Adding a light-transmitting confinement layer on the surface of the DD5 single crystal alloy that can accommodate the vertical propagation of high-amplitude plasma shock waves; the confinement layer is a flowing deionized water layer; Step 3, using laser marking software to design the marking area and marking pattern, the marking area is the area covered by the constraint layer, and the marking pattern is a four-pointed star; turning on the laser to perform laser marking on the DD5 single crystal alloy, the laser induces plastic deformation on the surface of the DD5 single crystal alloy, and the energy density of the laser is changed by adjusting the laser spot size and laser energy, thereby controlling the degree of laser-induced plastic deformation on the surface of the DD5 single crystal alloy to form a metallurgical micro-region; the metallurgical micro-region includes nano-grains, high-density grain boundaries and high residual compressive stress areas; repeating steps 1 to 3, performing the same laser marking on the GH4169 nickel-based alloy; Step 4: Assemble the laser-marked DD5 single crystal alloy, GH4169 nickel-based alloy, and Ni-based brazing filler metal to the correct weld surfaces, then place them in a vacuum brazing furnace for welding. The brazing temperature is 610°C, and the holding time is 2 minutes.

[0031] The microstructure, marking pattern and solder wetting structure of the brazed joint prepared by the brazing method of this embodiment are shown in FIG. Figure 3 As shown. Among them, Figure 3 a is the microstructure of the brazed joint, Figure 3 b is a schematic diagram of the marking pattern. Figure 3 c is the solder wetting organization diagram. Figure 3 It can be seen that the brazing method of this embodiment obtains a brazed joint with uniform structure and no defects, and the joint has good wettability.

[0032] Comparative Example 1

[0033] The difference between Comparative Example 1 and Example 1 is that the GH536 high-temperature alloy and the Nb521 niobium alloy were not laser marked. Instead, the GH536 high-temperature alloy, the Nb521 niobium alloy, and the Ti-based brazing filler metal (TiZrCuNi) were directly brazed at a brazing temperature of 1030°C and a holding time of 3 minutes.

[0034] Comparative Example 2

[0035] The difference between Comparative Example 2 and Example 2 is that the stainless steel and TC4 titanium alloy are not laser marked, and the stainless steel, TC4 titanium alloy and silver-based solder are directly brazed at a brazing temperature of 890°C and a holding time of 2 minutes.

[0036] Comparative Example 3

[0037] The difference between Comparative Example 3 and Example 3 is that the DD5 single crystal alloy and the GH4169 nickel-based alloy are not laser marked, and the DD5 single crystal alloy, the GH4169 nickel-based alloy and the Ni-based brazing filler metal are directly brazed at a brazing temperature of 610°C and a holding time of 2 minutes.

[0038] Performance Testing

[0039] The performance of the brazed joints prepared by the brazing methods of Examples 1 to 3 and Comparative Examples 1 to 3 were tested, and their shear strength was tested. The test results are shown in Table 1.

[0040] Table 1. Shear strength of brazed joints

[0041] As shown in Table 1, compared with Comparative Examples 1 to 3, the shear strength of the brazed joints prepared by the high-efficiency brazing methods based on laser marking technology provided by Examples 1 to 3 of the present invention is significantly improved.

Claims

1. An efficient brazing method based on laser marking technology, characterized in that: The steps include: Step 1: Use the laser marking system to fix the base material to be brazed, adjust the distance between the laser lens and the base material to be brazed, and adjust the laser marking system parameters; Step 2: Add a light-transmitting confinement layer on the surface of the base material to be brazed that can accommodate the vertical propagation of high-amplitude plasma shock waves; Step 3: Use laser marking software to design different marking patterns and marking areas; Turn on the laser to mark the base material to be brazed, and induce plastic deformation on the surface of the base material through the laser to form metallurgical micro-areas; Step 4: Assemble the laser-marked base material and the brazing filler metal so that they are aligned with the surfaces to be welded, ensuring that the brazing filler metal evenly covers the welding interface, and then place them in a vacuum brazing furnace for welding.

2. The high-efficiency brazing method based on laser marking technology according to claim 1, characterized in that: In step 1, the distance between the laser lens and the base material to be brazed is the focal length of the lens.

3. The efficient brazing method based on laser marking technology according to claim 1, characterized in that: The parameters of the laser marking system in step 1 are: laser power density: 2.5GW / cm²~4.5GW / cm²; pulse duration: 10ns~50ns; marking depth: 0.5μm~1.5μm; surface roughness optimization range: Ra=0.5μm~1.2μm.

4. The high-efficiency brazing method based on laser marking technology according to claim 1, characterized in that: The base materials to be brazed in step 1 include titanium alloy, stainless steel, niobium alloy, single crystal alloy and nickel-based alloy.

5. The high-efficiency brazing method based on laser marking technology according to claim 1, characterized in that: The constraining layer in step 2 is a flowing deionized water layer.

6. The high-efficiency brazing method based on laser marking technology according to claim 1, characterized in that: The marking pattern in step 3 includes honeycomb, periodic dot matrix or radial stripes.

7. The high-efficiency brazing method based on laser marking technology according to claim 1, characterized in that: During the laser marking process of the base material to be brazed in step 3, the marking area is covered by a constraint layer, and the laser cannot directly act on the surface of the base material to be brazed.

8. The high-efficiency brazing method based on laser marking technology according to claim 1, characterized in that: During the laser marking process in step 3, the laser energy density is changed by adjusting the laser spot size and laser energy, thereby controlling the degree of plastic deformation induced by the laser on the surface of the base material.

9. The high-efficiency brazing method based on laser marking technology according to claim 1, characterized in that: The metallurgical micro-regions in step 3 include nano-grains, high-density grain boundaries and high residual compressive stress regions.

10. The high-efficiency brazing method based on laser marking technology according to claim 1, characterized in that: In step 4, the brazing temperature is 10°C to 20°C above the melting point of the brazing material, and the holding time is 2 minutes to 3 minutes.

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