Laser beam processing method for aluminum-steel laser fusion brazing dot array high-entropy alloy transition layer

Abstract

The application provides a laser beam processing method of an aluminum-steel laser fusion brazing dot array high-entropy alloy transition layer, and steps include: constructing a dot array structure model of the aluminum-steel laser fusion brazing dot array high-entropy alloy transition layer; laying FeCoCrNiMn high-entropy alloy powder on a steel base by using a selective laser melting device; and performing laser processing on the FeCoCrNiMn high-entropy alloy powder according to the dot array structure model and path planning, so that the obtained aluminum-steel laser fusion brazing dot array high-entropy alloy transition layer is connected to an aluminum base. By using the application, the joint formed after the aluminum-steel laser fusion brazing dot array high-entropy alloy transition layer is connected to the base (parent material) has excellent performance and good forming quality.

Description

Technical Field

[0001] This invention relates to the field of laser beam processing of steel-aluminum composite components, specifically to a laser beam processing method for a high-entropy alloy transition layer of aluminum-steel laser brazing lattice. Background Technology

[0002] Laser brazing is currently the most promising method for welding dissimilar metals like aluminum and steel. It allows for precise control of welding heat input, shortens the aluminum / steel reaction time, and reduces the thickness of the interfacial reaction layer. However, aluminum and steel have significant differences in physicochemical properties and poor metallurgical compatibility. Two major problems still exist in the laser brazing process: first, the aluminum brazing filler metal has poor wettability on the steel surface, resulting in poor weld formation; second, brittle Fe-Al intermetallic compounds (such as FeAl3 and Fe2Al5) are easily formed at the interface, leading to brittle weld joints and low bonding strength, which seriously restricts the engineering application of aluminum-steel composite components.

[0003] To address the aforementioned issues, existing technical approaches mainly include three aspects: optimizing welding processes, adding alloying elements, and preparing microtextures on steel surfaces. However, all of these approaches have significant limitations. Optimizing welding processes can only improve wettability and joint quality to a certain extent, failing to fundamentally solve the problem. While adding alloying elements can regulate the interfacial chemical composition, it easily generates other harmful intermetallic compounds, causing secondary adverse effects on joint performance. Applying microtextures to steel surfaces cannot prevent direct contact between aluminum and iron elements and still cannot inhibit the formation and growth of brittle Fe-Al intermetallic compounds.

[0004] In addition, although laser drilling on the high-entropy alloy transition layer on the steel surface can improve the welding effect of aluminum and steel to a certain extent, the transition layer prepared by this method has problems such as low porosity and easy formation of closed pores during the welding process. After the high-entropy alloy transition layer is connected with the substrate (base material), macroscopic defects are easily formed and the uniformity of the interface structure is difficult to control, which restricts its engineering application. Summary of the Invention

[0005] The purpose of this invention is to at least solve the problems mentioned in the background art, and to provide a laser beam processing method for aluminum-steel laser brazing lattice high-entropy alloy transition layers.

[0006] To achieve the above objectives, the present invention adopts the following technical solution.

[0007] A laser beam processing method for laser brazing a high-entropy alloy transition layer in an aluminum-steel lattice, comprising the following steps:

[0008] Step 1: Select FeCoCrNiMn high-entropy alloy powder with a particle size of 15μm~53μm; select stainless steel as the steel matrix, clean it and set it aside.

[0009] Step 2: Construct a lattice structure model of the high-entropy alloy transition layer for aluminum-steel laser brazing;

[0010] Step 3: Using a selective laser melting device, FeCoCrNiMn high-entropy alloy powder is laid on a steel substrate. According to the lattice structure model and path planning, the FeCoCrNiMn high-entropy alloy powder is laser-processed to obtain an alloy part with a lattice high-entropy alloy cell skeleton.

[0011] Step 4: Clean the obtained alloy parts to obtain an aluminum-steel laser brazing lattice high-entropy alloy transition layer.

[0012] The aluminum-steel laser brazing lattice high-entropy alloy transition layer includes a lattice high-entropy alloy cell framework connected to a steel substrate. The porosity of the lattice high-entropy alloy cell framework is 60-80%, the pore size is 200-800 μm, and the thickness is 0.3-1 mm. The upper part of the lattice high-entropy alloy cell framework is used to connect to the aluminum substrate, and the pores of the lattice high-entropy alloy cell framework are used to fill aluminum-based brazing filler metal. In this invention, liquid aluminum brazing filler metal refers to the liquid aluminum brazing filler metal formed after the aluminum substrate and the welding wire are melted.

[0013] Preferably, the type of the high-entropy alloy lattice cell framework is one or more combinations of face-centered cubic structure, body-centered cubic structure, and rhombic dodecahedral structure.

[0014] Preferably, the alloy parts are cleaned by blowing away unmelted powder with high-pressure argon gas and removing burrs by sanding with sandpaper.

[0015] Preferably, the process conditions during laser processing are as follows: the processing area is protected by argon gas, the laser power is 150W~300W, the scanning speed is 800mm / s~2000mm / s, the layer thickness is 20μm~50μm, the scanning spacing is 50μm~100μm, and the oxygen content is ≤0.1%.

[0016] Furthermore, it also includes step 5, which is used to connect the high-entropy alloy transition layer of the aluminum-steel laser brazing lattice obtained in step 4 to the aluminum substrate (base material):

[0017] Step 51: The workpiece processed in step 4 is clamped and positioned with the aluminum substrate. The overlapping area of ​​the aluminum substrate is located on the top surface of the high-entropy alloy transition layer of the aluminum-steel laser brazing lattice. The clamping gap is ≤0.1mm.

[0018] Step 52: Using laser brazing equipment and AISi12 welding wire, focus the laser beam onto the AISi12 welding wire, set the laser brazing process parameters, and then process it so that the liquid aluminum brazing material formed by melting the aluminum matrix and AISi12 welding wire wets, spreads and fills the pores of the lattice high-entropy alloy cell skeleton.

[0019] After steps 52 and 53 are completed, the workpiece is allowed to cool naturally.

[0020] Preferably, the laser brazing process parameters are: laser power 800W~2000W, welding speed 1m / min~3m / min, defocusing amount -5mm~+5mm, shielding gas is argon, and gas flow rate 10L / min~15L / min.

[0021] To further improve the joint performance formed after the high-entropy alloy transition layer is bonded to the substrate (base material), the present invention plans the path according to the following steps:

[0022] Step 31: Divide the lattice structure model into N forming unit layers along the height direction, where N is a positive integer greater than a preset threshold. Each forming unit layer contains at least one unit cell layer. Based on the unit cell geometric topology, divide the scanning area within each forming unit layer into a unit cell pillar region and a unit cell node region.

[0023] Step 32: For the unit cell pillar region, the first laser scanning strategy is adopted: the laser beam performs unidirectional continuous scanning along the pillar axis, the scanning speed is greater than the preset speed threshold, and the laser power is adjusted in a gradient according to the pillar cross-sectional size. Thin pillars with cross-sectional sizes smaller than the preset size threshold correspond to lower power, and thick pillars with cross-sectional sizes larger than the preset size threshold correspond to higher power.

[0024] Step 33: For the unit cell node region, a second laser scanning strategy is adopted: the laser beam performs a ring or cross-shaped scan around the node center, the laser power is higher than the power of the thin pillar region but lower than the power of the coarse pillar region, the scanning speed is lower than the scanning speed of the first laser scanning strategy, and the dwell time is greater than the preset time threshold to ensure that the powder at the node is fully fused.

[0025] Step 34: Steps 32 and 33 are executed layer by layer in a bottom-up order. The scanning direction between adjacent forming unit layers rotates at a preset angle, which is greater than 0° and less than 180°.

[0026] To further improve the joint performance formed after the high-entropy alloy transition layer is bonded to the substrate (base material), the following are also included:

[0027] Step 35: During the scanning process, dynamically identify and mark cell pillars in the current forming unit layer whose suspended span is greater than a preset span threshold as suspended pillars, and generate an auxiliary support scanning path below the suspended pillars; the laser power of the auxiliary support scanning path is lower than the laser power of the cell pillar region, and the scanning speed is higher than the scanning speed of the cell pillar region, forming a microscale support structure that is metallurgically bonded to the suspended pillars; after completing the main scanning of the current forming unit layer, perform supplementary scanning according to the auxiliary support scanning path; when subsequent forming unit layers cover the microscale support structure, the microscale support structure is remelted and fused with the upper cell pillars to form a whole.

[0028] To further improve the joint performance formed after the high-entropy alloy transition layer is connected to the substrate (base material), the steps for constructing the lattice structure model in this invention include:

[0029] Step 21: Obtain the difference in thermal expansion coefficients between the aluminum substrate and the steel substrate and the heat input distribution characteristics of laser brazing, and determine the thermal stress gradient distribution along the thickness direction of the transition layer;

[0030] Step 22: Based on the thermal stress gradient distribution, the transition layer is divided along the thickness direction into a first functional layer near the steel substrate, an intermediate second functional layer, and a third functional layer near the aluminum substrate. The cell pillar diameter of the first functional layer is greater than a preset diameter threshold and the porosity is lower than a preset porosity threshold to provide a high-strength metallurgical bond with the steel substrate. The cell pillar diameter of the third functional layer is smaller than the preset diameter threshold and the porosity is higher than the preset porosity threshold to enhance the capillary wetting effect of the liquid aluminum solder. The cell pillar diameter and porosity of the second functional layer are between those of the first and third functional layers, forming a thermal stress buffer gradient.

[0031] Step 23: Each functional layer adopts the same or different cell types, and the cell node positions of adjacent functional layers are aligned or staggered according to a preset offset to ensure the continuity of the interlayer structure.

[0032] Beneficial effects:

[0033] Using the solution of this invention, the joint formed after the high-entropy alloy transition layer of aluminum-steel laser brazing lattice is connected to the substrate (base material) has excellent performance and good forming quality;

[0034] The high-entropy alloy transition layer of aluminum-steel laser brazing lattice prepared by the present invention can effectively inhibit the formation and growth of Fe-Al brittle intermetallic compounds at the aluminum-steel interface, reduce interface brittleness, make its thermal expansion coefficient between that of aluminum and steel, and alleviate the thermal stress caused by the mismatch of thermal expansion coefficients during the welding process.

[0035] The high-entropy alloy transition layer of the aluminum-steel laser brazing lattice prepared by this invention is an ordered three-dimensional interconnected open porous structure with high porosity, good connectivity, and significant capillary effect. This is beneficial for the full wetting, spreading, and pore filling of liquid aluminum brazing filler metal, significantly reducing the wetting angle of aluminum-based brazing filler metal, improving the weld formation effect, avoiding the formation of macroscopic defects such as incomplete fusion and porosity in the weld joint (lap joint), and simultaneously enabling the continuous layered distribution of brittle phases to alleviate interfacial stress concentration. It also enhances the ductility and toughness of the weld joint, achieving the strengthening and toughening of the aluminum-steel weld joint and improving the tensile strength of the aluminum-steel dissimilar weld joint.

[0036] The processing method of the present invention is simple, easy to control, and has high processing efficiency. It can directly form a transition layer on the surface of a steel substrate. Applying this transition layer to aluminum-steel laser brazing can be easily automated and is suitable for the large-scale welding manufacturing of aluminum-steel composite components. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of laser beam processing for the high-entropy alloy transition layer of the aluminum-steel laser brazing lattice in the embodiment;

[0038] Figure 2 The diagram shows the type of high-entropy alloy cell framework in the embodiment. Part A represents body-centered cubic structure one, part B represents body-centered cubic structure two, part C represents face-centered cubic structure, part D represents reinforced body-centered cubic structure, and part E represents reinforced face-centered cubic structure.

[0039] Figure 3 For comparison, the microscopic view of the joint fracture site in Example 1 is shown in part (c), which is a partial view of part (b).

[0040] Figure 4 This is a cross-sectional view of the high-entropy alloy transition layer of the aluminum-steel laser brazing lattice obtained in the embodiment. Detailed Implementation

[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. 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.

[0042] Example 1

[0043] A laser beam processing method for laser brazing a high-entropy alloy transition layer in an aluminum-steel lattice, comprising the following steps:

[0044] Step 1: Select FeCoCrNiMn high-entropy alloy powder with a particle size of 15μm~53μm and place it in a vacuum drying oven. Dry it at 80℃ for 4 hours to remove moisture and impurities. Select 304 stainless steel as the steel substrate and polish the surface to be welded (processed) with 2000-grit sandpaper until bright. Then, place it in acetone for ultrasonic cleaning for 20 minutes, rinse with anhydrous ethanol, and dry at 80℃ for later use.

[0045] Step 2: Construct a lattice structure model of the high-entropy alloy transition layer of aluminum-steel laser brazing. The high-entropy alloy lattice cell skeleton type is a rhombic dodecahedral structure with a porosity of 75%, a pore size of 500 μm, and a lattice thickness of 1 mm.

[0046] Step 3: Using a selective laser melting (SLM) device, the spare steel substrate is fixed on the forming platform of the SLM device. FeCoCrNiMn high-entropy alloy powder is laid on the steel substrate. According to the lattice structure model and path planning, the FeCoCrNiMn high-entropy alloy powder is laser-processed (the process conditions during laser processing are: the processing area is protected by argon gas, the laser power is 200W, the scanning speed is 1200mm / s, the layer thickness is 30μm, the scanning spacing is 70μm, and the oxygen content is 0.08%), to obtain an alloy part with a lattice high-entropy alloy cell skeleton.

[0047] Step 4: Clean the obtained alloy parts (use high-pressure argon gas to blow away unmelted powder on the workpiece and use sandpaper to polish and remove burrs) to obtain an aluminum-steel laser brazing lattice high-entropy alloy transition layer.

[0048] The aluminum-steel laser brazing lattice high-entropy alloy transition layer includes a lattice high-entropy alloy cell skeleton connected to the steel substrate. The lattice high-entropy alloy cell skeleton has a porosity of 75% (negligible processing error), a pore size of 500μm (negligible processing error), and a thickness of 1mm (negligible processing error). The upper part of the lattice high-entropy alloy cell skeleton is used to connect to the aluminum substrate, and the pores of the lattice high-entropy alloy cell skeleton are used to fill aluminum-based brazing filler metal.

[0049] Step 5, combined Figure 1 and Figure 4 As shown in the attached figure, the reference numerals are: steel substrate 1, aluminum-steel laser brazing lattice high-entropy alloy transition layer 2, aluminum substrate 3, argon gas supply pipe 4, laser beam emitted by the laser brazing equipment 5, and AISi12 welding wire 6. This step is used to connect the aluminum-steel laser brazing lattice high-entropy alloy transition layer obtained in step 4 to the aluminum substrate, as detailed below:

[0050] Step 51: The workpiece processed in step 4 is clamped and positioned with the aluminum substrate (6061 aluminum alloy). The overlapping area of ​​the aluminum substrate is located on the top surface of the high-entropy alloy transition layer of the aluminum-steel laser brazing lattice, and the clamping gap is 0.08mm.

[0051] Step 52: Using laser brazing equipment and AISi12 welding wire, focus the laser beam onto the AISi12 welding wire, set the laser brazing process parameters and perform processing (laser brazing process parameters are: laser power 1200W, welding speed 2m / min, defocusing amount 0mm, shielding gas is argon, gas flow rate 13L / min), so that the liquid aluminum brazing material formed by melting the aluminum matrix and AISi12 welding wire wets, spreads and fills the pores of the lattice high-entropy alloy cell skeleton, and undergoes an interfacial reaction with the transition layer and stainless steel;

[0052] After steps 53 and 52 are completed, the workpiece is allowed to cool naturally to room temperature to obtain a component with a high-entropy alloy transition layer with aluminum-steel laser brazing lattice.

[0053] The performance of the component sample prepared in Example 1 was tested. The results showed that the wetting angle of the aluminum-based brazing filler metal at the welding interface was 28°, there was no obvious brittle Fe-Al intermetallic compound continuous layer at the interface, the tensile strength of the welded joint reached 378 N / mm, the fracture location of the joint was located in the aluminum matrix (i.e. aluminum alloy base material), and the fracture mode was ductile fracture.

[0054] Example 2

[0055] A laser beam processing method for laser brazing a high-entropy alloy transition layer in an aluminum-steel lattice, comprising the following steps:

[0056] Step 1: Select FeCoCrNiMn high-entropy alloy powder with a particle size of 15μm~53μm and place it in a vacuum drying oven. Dry it at 120℃ for 2 hours to remove moisture and impurities. Select 316L stainless steel as the steel substrate and polish the surface to be welded (processed) with 2000-grit sandpaper until it is bright. Then, place it in acetone for ultrasonic cleaning for 10 minutes, rinse with anhydrous ethanol, and dry it at 60℃ for later use.

[0057] Step 2: Construct a lattice structure model for the high-entropy alloy transition layer of aluminum-steel laser brazing, wherein the high-entropy alloy lattice cell framework is a face-centered cubic structure (e.g., ...). Figure 2 As shown in section C), the porosity is 75%, the pore size is 300 μm, and the lattice thickness is 0.5 mm;

[0058] Step 3: Using a selective laser melting (SLM) device, the spare steel substrate is fixed on the forming platform of the SLM device. FeCoCrNiMn high-entropy alloy powder is laid on the steel substrate. According to the lattice structure model and path planning, the FeCoCrNiMn high-entropy alloy powder is laser-processed (the process conditions during laser processing are: the processing area is protected by argon gas, the laser power is 250W, the scanning speed is 1500mm / s, the layer thickness is 40μm, the scanning spacing is 80μm, and the oxygen content is 0.08%), to obtain an alloy part with a lattice high-entropy alloy cell skeleton.

[0059] Step 4: Clean the obtained alloy parts (use high-pressure argon gas to blow away unmelted powder on the workpiece and use sandpaper to polish and remove burrs) to obtain an aluminum-steel laser brazing lattice high-entropy alloy transition layer.

[0060] The aluminum-steel laser brazing lattice high-entropy alloy transition layer includes a lattice high-entropy alloy cell skeleton connected to the steel substrate. The lattice high-entropy alloy cell skeleton has a porosity of 75% (negligible processing error), a pore size of 300μm (negligible processing error), and a thickness of 0.5mm (negligible processing error). The upper part of the lattice high-entropy alloy cell skeleton is used to connect to the aluminum substrate, and the pores of the lattice high-entropy alloy cell skeleton are used to fill aluminum-based brazing filler metal.

[0061] Step 5, combined Figure 1 and Figure 4 As shown in the attached diagram, the reference numerals are: steel substrate 1, high-entropy alloy transition layer of aluminum-steel laser brazing lattice 2, aluminum substrate 3, argon gas supply pipe 4, laser beam emitted by the laser brazing equipment 5, AISi12 welding wire 6; the specific steps are as follows:

[0062] Step 51: The workpiece processed in step 4 is clamped and positioned with the aluminum substrate (5052 aluminum alloy). The overlapping area of ​​the aluminum substrate is located on the top surface of the high-entropy alloy transition layer of the aluminum-steel laser brazing lattice, and the clamping gap is 0.05mm.

[0063] Step 52: Using laser brazing equipment and AISi12 welding wire, focus the laser beam onto the AISi12 welding wire, set the laser brazing process parameters and proceed with the process (laser brazing process parameters are: laser power 1500W, welding speed 1.5m / min, defocusing amount +3mm, shielding gas is argon, gas flow rate 13L / min). This allows the liquid aluminum brazing filler metal formed by melting the aluminum substrate and AISi12 welding wire to wet, spread and fill the pores of the lattice high-entropy alloy cell skeleton, and to undergo an interfacial reaction with the transition layer and stainless steel.

[0064] After steps 53 and 52 are completed, the workpiece is allowed to cool naturally to room temperature to obtain a component with a high-entropy alloy transition layer with aluminum-steel laser brazing lattice.

[0065] The performance of the component sample prepared in Example 2 was tested. The results showed that the wetting angle of the aluminum-based brazing filler metal at the welding interface was 25°, the brittle phase at the interface was discretely distributed and there was no continuous layer, the tensile strength of the welded joint was 391 N / mm, the joint fractured in the aluminum matrix (i.e. the aluminum alloy base material), and the ductile fracture characteristics were obvious.

[0066] Example 3

[0067] A laser beam processing method for laser brazing a high-entropy alloy transition layer in an aluminum-steel lattice, comprising the following steps:

[0068] Step 1: Select FeCoCrNiMn high-entropy alloy powder with a particle size of 15μm~53μm and place it in a vacuum drying oven. Dry it at 100℃ for 3 hours to remove moisture and impurities. Select 2025 stainless steel as the steel substrate and polish the surface to be welded (processed) with 2000-grit sandpaper until it is bright. Then, place it in acetone for ultrasonic cleaning for 15 minutes, rinse with anhydrous ethanol, and dry it at 70℃ for later use.

[0069] Step 2: Construct a lattice structure model for the high-entropy alloy transition layer of aluminum-steel laser brazing, wherein the high-entropy alloy lattice cell framework is a body-centered cubic structure (e.g., ...). Figure 2 As shown in Part B), the porosity is 75%, the pore size is 700 μm, and the lattice thickness is 0.3 mm.

[0070] Step 3: Using a selective laser melting (SLM) device and AISi12 welding wire, the spare steel substrate is fixed on the forming platform of the SLM device. FeCoCrNiMn high-entropy alloy powder is laid on the steel substrate. According to the lattice structure model and path planning, the FeCoCrNiMn high-entropy alloy powder is laser-processed (the process conditions during laser processing are: the processing area is protected by argon gas, the laser power is 180W, the scanning speed is 1000mm / s, the layer thickness is 25μm, the scanning spacing is 60μm, and the oxygen content is 0.08%), to obtain an alloy part with a lattice high-entropy alloy cell skeleton.

[0071] Step 4: Clean the obtained alloy parts (use high-pressure argon gas to blow away unmelted powder on the workpiece and use sandpaper to polish and remove burrs) to obtain an aluminum-steel laser brazing lattice high-entropy alloy transition layer.

[0072] The aluminum-steel laser brazing lattice high-entropy alloy transition layer includes a lattice high-entropy alloy cell skeleton connected to the steel substrate. The lattice high-entropy alloy cell skeleton has a porosity of 75% (negligible processing error), a pore size of 700μm (negligible processing error), and a thickness of 0.3mm (negligible processing error). The upper part of the lattice high-entropy alloy cell skeleton is used to connect to the aluminum substrate, and the pores of the lattice high-entropy alloy cell skeleton are used to fill aluminum-based brazing filler metal.

[0073] Step 5, combined Figure 1 and Figure 4 As shown in the attached diagram, the reference numerals are: steel substrate 1, high-entropy alloy transition layer of aluminum-steel laser brazing lattice 2, aluminum substrate 3, argon gas supply pipe 4, laser beam emitted by the laser brazing equipment 5, AISi12 welding wire 6; the specific steps are as follows:

[0074] Step 51: The workpiece processed in step 4 is clamped and positioned with the aluminum substrate (2A12 aluminum alloy). The overlapping area of ​​the aluminum substrate is located on the top surface of the high-entropy alloy transition layer of the aluminum-steel laser brazing lattice, and the clamping gap is 0.1mm.

[0075] Step 52: Using laser brazing equipment, focus the laser beam onto the AISi12 welding wire, set the laser brazing process parameters and perform the process (laser brazing process parameters are: laser power 900W, welding speed 2.5m / min, defocusing amount -2mm, shielding gas is argon, gas flow rate 13L / min), so that the liquid aluminum brazing material formed by melting the aluminum matrix and AISi12 welding wire wets, spreads and fills the pores of the lattice high-entropy alloy cell skeleton, and reacts with the transition layer and stainless steel at the interface;

[0076] After steps 53 and 52 are completed, the workpiece is allowed to cool naturally to room temperature to obtain a component with a high-entropy alloy transition layer with aluminum-steel laser brazing lattice.

[0077] The performance of the component sample prepared in Example 3 was tested. The results showed that the wetting angle of the aluminum-based brazing filler metal at the welding interface was 30°, there was no continuous brittle phase layer at the interface, the tensile strength of the welded joint reached 362 MPa, the fracture location of the joint was located in the aluminum matrix (i.e. aluminum alloy base material), and the fracture mode was ductile fracture.

[0078] In other embodiments, the type of lattice high-entropy alloy cell framework can be selected as such as... Figure 2 The porosity of the lattice high-entropy alloy cell framework, as shown in one or more structural combinations, can be selected within the range of 60-80%.

[0079] Comparative Example 1: 316L stainless steel was selected as the steel substrate. A high-entropy alloy transition layer was welded onto the surface of the steel substrate and ground to a thickness of 0.5 mm. Then, laser drilling was used on the high-entropy alloy transition layer to obtain a porous high-entropy alloy transition layer with an overall porosity of 75% and a pore size of 300 μm. The component was then prepared according to step 5 of Example 2. Performance tests were conducted on the component samples prepared in Comparative Example 1. The results showed that the wetting angle of the aluminum-based brazing filler metal at the welding interface was 67°, the tensile strength of the welded joint was 297 N / mm, and the fracture site of the joint (e.g., Figure 3 (As shown) is located in the high-entropy alloy transition layer.

[0080] Example 4

[0081] A laser beam processing method for laser brazing a high-entropy alloy transition layer in an aluminum-steel lattice, comprising the following steps:

[0082] Step 1: Select FeCoCrNiMn high-entropy alloy powder with a particle size of 15μm~53μm and place it in a vacuum drying oven. Dry it at 80℃ for 4 hours to remove moisture and impurities. Select 304 stainless steel as the steel substrate and polish the surface to be welded (processed) with 2000-grit sandpaper until bright. Then, place it in acetone for ultrasonic cleaning for 20 minutes, rinse with anhydrous ethanol, and dry at 80℃ for later use.

[0083] Step 2: Construct a lattice structure model of the high-entropy alloy transition layer of aluminum-steel laser brazing. The high-entropy alloy lattice cell skeleton type is a rhombic dodecahedral structure with a porosity of 75%, a pore size of 500 μm, and a lattice thickness of 1 mm.

[0084] Step 3: Using a selective laser melting (SLM) device, the prepared steel substrate is fixed on the forming platform of the SLM device. FeCoCrNiMn high-entropy alloy powder is laid on the steel substrate. According to the lattice structure model and path planning, the FeCoCrNiMn high-entropy alloy powder is laser-processed to obtain an alloy part with a lattice high-entropy alloy cell skeleton. During the laser processing: the processing area is protected by argon gas, the layer thickness is 30μm, the scanning interval is 70μm, and the oxygen content is 0.08%.

[0085] The path planning is performed according to the following steps:

[0086] Step 31: Divide the lattice structure model into 20 forming unit layers along the height direction (each forming unit layer contains 2 unit cell layers, for a total of 40 layers); based on the face-centered cubic unit cell geometry and topology, divide the scanning area within each forming unit layer into a unit cell pillar region (pillar diameter approximately 120 μm) and a unit cell node region (node ​​diameter approximately 200 μm).

[0087] Step 32: For the column region of the unit cell, the first laser scanning strategy is adopted: the laser beam performs unidirectional continuous scanning along the column axis at a scanning speed of 1200 mm / s. The laser power is adjusted in a gradient according to the column cross-sectional size. The laser power is 180 W for thin columns with a cross-sectional size of less than 150 μm and 220 W for thick columns with a cross-sectional size of greater than or equal to 150 μm.

[0088] Step 33: For the unit cell node region, a second laser scanning strategy is adopted: the laser beam performs a ring scan around the node center, with a laser power of 200W, a scanning speed of 1200mm / s, and a dwell time of 0.5ms, to ensure that the powder at the node is fully fused.

[0089] Step 34: Perform steps 3b and 3c layer by layer in a bottom-up order, with the scanning direction between adjacent forming unit layers rotating at 67°, until an alloy part with a high-entropy alloy cell skeleton is obtained.

[0090] Step 4: Clean the obtained alloy parts (use high-pressure argon gas to blow away unmelted powder on the workpiece and use sandpaper to polish and remove burrs) to obtain an aluminum-steel laser brazing lattice high-entropy alloy transition layer.

[0091] The aluminum-steel laser brazing lattice high-entropy alloy transition layer includes a lattice high-entropy alloy cell skeleton connected to the steel substrate. The porosity of the lattice high-entropy alloy cell skeleton is 75% (processing error is negligible), the pore size is 400μm (processing error is negligible), and the thickness is 1mm (processing error is negligible). The upper part of the lattice high-entropy alloy cell skeleton is used to connect to the aluminum substrate, and the pores of the lattice high-entropy alloy cell skeleton are used to fill aluminum-based brazing filler metal.

[0092] Step 51: The workpiece processed in step 4 is clamped and positioned with the aluminum substrate (6061 aluminum alloy). The overlapping area of ​​the aluminum substrate is located on the top surface of the high-entropy alloy transition layer of the aluminum-steel laser brazing lattice, and the clamping gap is 0.08mm.

[0093] Step 52: Using laser brazing equipment, focus the laser beam onto the AISi12 welding wire, set the laser brazing process parameters and perform the process (laser brazing process parameters are: laser power 1200W, welding speed 2m / min, defocusing amount 0mm, shielding gas is argon, gas flow rate 13L / min), so that the liquid aluminum brazing material formed by melting the aluminum matrix and AISi12 welding wire wets, spreads and fills the pores of the lattice high-entropy alloy cell skeleton, and undergoes an interfacial reaction with the transition layer and stainless steel;

[0094] After steps 53 and 52 are completed, the workpiece is allowed to cool naturally to room temperature to obtain a component with a high-entropy alloy transition layer with aluminum-steel laser brazing lattice.

[0095] Performance tests were conducted on the component samples prepared in Example 4. The results showed that the wetting angle of the aluminum-based brazing filler metal at the welding interface was 25°, there was no obvious brittle Fe-Al intermetallic compound continuous layer at the interface, the tensile strength of the welded joint reached 398 N / mm, and the fracture location of the joint was located in the aluminum matrix (i.e., the aluminum alloy base material), exhibiting ductile fracture. In this example, after adopting the partitioned variable parameter scanning strategy, the tensile strength of the joint was further improved compared to Example 1, and the wetting angle decreased by approximately 3°, indicating that this scanning strategy can further improve the forming quality of the lattice framework, thereby enhancing the performance of the welded joint.

[0096] Example 5

[0097] A laser beam processing method for laser brazing a high-entropy alloy transition layer in an aluminum-steel lattice, comprising the following steps:

[0098] Step 1: Select FeCoCrNiMn high-entropy alloy powder with a particle size of 15μm~53μm and place it in a vacuum drying oven. Dry it at 120℃ for 2 hours to remove moisture and impurities. Select 316L stainless steel as the steel substrate and polish the surface to be welded (processed) with 2000-grit sandpaper until it is bright. Then, place it in acetone for ultrasonic cleaning for 10 minutes, rinse with anhydrous ethanol, and dry it at 60℃ for later use.

[0099] Step 2: Construct a lattice structure model for the high-entropy alloy transition layer of aluminum-steel laser brazing, wherein the high-entropy alloy lattice cell framework is a body-centered cubic structure (e.g., ...). Figure 2 As shown in Part B), the porosity is 75%, the pore size is 300 μm, and the lattice thickness is 0.5 mm.

[0100] Step 3: Using a selective laser melting (SLM) device, the prepared steel substrate is fixed on the forming platform of the SLM device. FeCoCrNiMn high-entropy alloy powder is laid on the steel substrate. According to the lattice structure model and path planning, the FeCoCrNiMn high-entropy alloy powder is laser-processed to obtain an alloy part with a lattice high-entropy alloy cell skeleton. The process conditions during laser processing are: the processing area is protected by argon gas, the layer thickness is 40 μm, the scanning interval is 80 μm, and the oxygen content is 0.08%.

[0101] The path planning is performed according to the following steps:

[0102] Step 31: Divide the lattice structure model into 15 forming unit layers along the height direction (each forming unit layer contains approximately 3 unit cell layers); based on the body-centered cubic unit cell geometry and topology, divide the scanning area within each forming unit layer into unit cell pillar regions and unit cell node regions;

[0103] Step 32: For the support column region of the unit cell, the first laser scanning strategy is adopted: the laser beam performs unidirectional continuous scanning along the axis of the support column, the scanning speed is 1200mm / s, and the laser power is adjusted in a gradient according to the cross-sectional size of the support column. The laser power is 200W for thin support columns with a cross-sectional size of less than 130μm, and the laser power is 250W for thick support columns with a cross-sectional size of greater than or equal to 130μm.

[0104] Step 33: For the unit cell node region, a second laser scanning strategy is adopted: the laser beam performs a cross-shaped scan around the node center, with a laser power of 230W, a scanning speed of 900mm / s, and a dwell time of 0.8ms.

[0105] Step 34: Perform steps 3b and 3c layer by layer in a bottom-up order, with the scanning direction between adjacent forming unit layers rotating by 90°; until an alloy part with a high-entropy alloy lattice cell skeleton is obtained;

[0106] Step 35: Identify cell pillars with a suspended span greater than 300 μm in the current forming unit layer, and generate an auxiliary support scanning path below the suspended pillars; the laser power of the auxiliary support scanning path is 150 W, and the scanning speed is 2000 mm / s, forming a microscale support structure (support width approximately 80 μm and height approximately 25 μm) that is metallurgically bonded to the suspended pillars; after completing the main scanning of the current forming unit layer, a supplementary scan is performed according to the auxiliary support scanning path; when subsequent forming unit layers cover the microscale support structure, the microscale support structure is remelted and fused with the upper cell pillars to form a whole;

[0107] Step 4: Clean the obtained alloy parts (use high-pressure argon gas to blow away unmelted powder on the workpiece and use sandpaper to polish and remove burrs) to obtain an aluminum-steel laser brazing lattice high-entropy alloy transition layer.

[0108] The aluminum-steel laser brazing lattice high-entropy alloy transition layer includes a lattice high-entropy alloy cell skeleton connected to the steel substrate. The porosity of the lattice high-entropy alloy cell skeleton is 75% (processing error is negligible), the pore size is 300μm (processing error is negligible), and the thickness is 0.5mm (processing error is negligible). The upper part of the lattice high-entropy alloy cell skeleton is used to connect to the aluminum substrate, and the pores of the lattice high-entropy alloy cell skeleton are used to fill aluminum-based brazing filler metal.

[0109] Step 51: The workpiece processed in step 4 is clamped and positioned with the aluminum substrate (5052 aluminum alloy). The overlapping area of ​​the aluminum substrate is located on the top surface of the high-entropy alloy transition layer of the aluminum-steel laser brazing lattice, and the clamping gap is 0.06mm.

[0110] Step 52: Using laser brazing equipment and AlSi12 welding wire, focus the laser beam onto the AlSi12 welding wire, set the laser brazing process parameters and proceed with the process (laser brazing process parameters are: laser power 1500W, welding speed 1.5m / min, defocusing amount +3mm, shielding gas is argon, gas flow rate 13L / min). This allows the liquid aluminum brazing filler metal formed by melting the aluminum matrix and AlSi12 welding wire to wet, spread and fill the pores of the lattice high-entropy alloy cell skeleton, and to react with the transition layer and stainless steel at the interface.

[0111] After steps 53 and 52 are completed, the workpiece is allowed to cool naturally to room temperature to obtain a component with a high-entropy alloy transition layer with aluminum-steel laser brazing lattice.

[0112] The performance of the component sample prepared in Example 5 was tested. The results showed that the wetting angle of the aluminum-based brazing filler metal at the welding interface was 22°, the brittle phase at the interface was discretely distributed and there was no continuous layer, the tensile strength of the welded joint reached 408 N / mm, the joint fractured in the aluminum matrix (i.e. the aluminum alloy base material), and the ductile fracture characteristics were obvious.

[0113] Compared with Example 2, the tensile strength of the joint was further improved and the wetting angle was further optimized after adopting the in-situ self-supporting strategy. Furthermore, there was no mechanical damage on the surface of the lattice skeleton, the pore connectivity was good, and no pillar breakage or node damage occurred due to support removal.

[0114] Example 6

[0115] A laser beam processing method for laser brazing a high-entropy alloy transition layer in an aluminum-steel lattice, comprising the following steps:

[0116] Step 1: Select FeCoCrNiMn high-entropy alloy powder with a particle size of 15μm~53μm and place it in a vacuum drying oven. Dry it at 120℃ for 2 hours to remove moisture and impurities. Select 316L stainless steel as the steel substrate and polish the surface to be welded (processed) with 2000-grit sandpaper until it is bright. Then, place it in acetone for ultrasonic cleaning for 10 minutes, rinse with anhydrous ethanol, and dry it at 60℃ for later use.

[0117] Step 2: Construct a lattice structure model for the high-entropy alloy transition layer of aluminum-steel laser brazing, wherein the high-entropy alloy lattice cell framework is a body-centered cubic structure (e.g., ...). Figure 2 As shown in Part B), the porosity is 75%, the pore size is 300 μm, and the lattice thickness is 0.5 mm; specifically, it is carried out in the following manner:

[0118] Step 21, obtain 6061 aluminum alloy (thermal expansion coefficient approximately 23.6 × 10⁻⁶). -6 / ℃) and 2205 duplex stainless steel (coefficient of thermal expansion approximately 13.7×10) -6The difference in the coefficient of thermal expansion (°C) is 9.9 × 10⁻⁶. -6 Based on the temperature and the heat input distribution characteristics of laser brazing (laser power 1200W, welding speed 2m / min, heat input approximately 36J / mm), the thermal stress gradient distribution along the thickness direction of the transition layer is determined to be: the thermal stress is greatest near the steel substrate, the thermal stress is smaller near the aluminum substrate, and the thermal stress in the middle region decreases nonlinearly.

[0119] Step 22: Based on the thermal stress gradient distribution, the transition layer is divided into three functional layers along the thickness direction:

[0120] The first functional layer (close to the steel substrate, 0.1 mm thick): adopts a body-centered cubic structure with a cell pillar diameter of 180 μm and a porosity of 60% to provide a high-strength metallurgical bond with the steel substrate.

[0121] The second functional layer (intermediate buffer layer, 0.3 mm thick) adopts a face-centered cubic structure with a cell pillar diameter of 140 μm and a porosity of 75%, forming a thermal stress buffer gradient.

[0122] The third functional layer (close to the aluminum substrate, 0.1 mm thick): adopts a rhombic dodecahedral structure with a cell pillar diameter of 100 μm and a porosity of 85% to enhance the capillary wetting effect of liquid aluminum solder.

[0123] Step 23: Each functional layer adopts a different cell type, and the cell node positions between adjacent functional layers are staggered by 1 / 2 cell side length to ensure the continuity of the interlayer structure.

[0124] Step 3: Using a selective laser melting (SLM) device, the prepared steel substrate is fixed on the forming platform of the SLM device. FeCoCrNiMn high-entropy alloy powder is laid on the steel substrate. According to the lattice structure model and path planning, the FeCoCrNiMn high-entropy alloy powder is laser-processed to obtain an alloy part with a lattice high-entropy alloy cell skeleton. The process conditions during laser processing are: the processing area is protected by argon gas, the layer thickness is 40 μm, the scanning interval is 80 μm, and the oxygen content is 0.08%.

[0125] The path planning is performed according to the following steps:

[0126] Step 31: Divide the lattice structure model into 15 forming unit layers along the height direction (each forming unit layer contains approximately 3 unit cell layers); based on the body-centered cubic unit cell geometry and topology, divide the scanning area within each forming unit layer into unit cell pillar regions and unit cell node regions;

[0127] Step 32: For the support column region of the unit cell, the first laser scanning strategy is adopted: the laser beam performs unidirectional continuous scanning along the axis of the support column, the scanning speed is 1200mm / s, and the laser power is adjusted in a gradient according to the cross-sectional size of the support column. The laser power is 200W for thin support columns with a cross-sectional size of less than 130μm, and the laser power is 250W for thick support columns with a cross-sectional size of greater than or equal to 130μm.

[0128] Step 33: For the unit cell node region, a second laser scanning strategy is adopted: the laser beam performs a cross-shaped scan around the node center, with a laser power of 230W, a scanning speed of 900mm / s, and a dwell time of 0.8ms.

[0129] Step 34: Perform steps 3b and 3c layer by layer in a bottom-up order, with the scanning direction between adjacent forming unit layers rotating by 90°; until an alloy part with a high-entropy alloy lattice cell skeleton is obtained;

[0130] Step 35: Identify cell pillars with a suspended span greater than 300 μm in the current forming unit layer, and generate an auxiliary support scanning path below the suspended pillars; the laser power of the auxiliary support scanning path is 150 W, and the scanning speed is 2000 mm / s, forming a microscale support structure (support width approximately 80 μm and height approximately 25 μm) that is metallurgically bonded to the suspended pillars; after completing the main scanning of the current forming unit layer, a supplementary scan is performed according to the auxiliary support scanning path; when subsequent forming unit layers cover the microscale support structure, the microscale support structure is remelted and fused with the upper cell pillars to form a whole;

[0131] Step 4: Clean the obtained alloy parts (use high-pressure argon gas to blow away unmelted powder on the workpiece and use sandpaper to polish and remove burrs) to obtain an aluminum-steel laser brazing lattice high-entropy alloy transition layer.

[0132] The aluminum-steel laser brazing lattice high-entropy alloy transition layer includes a lattice high-entropy alloy cell skeleton connected to the steel substrate. The porosity of the lattice high-entropy alloy cell skeleton is approximately 75% (negligible processing error), the pore size is 300μm (negligible processing error), and the thickness is 0.5mm (negligible processing error). The upper part of the lattice high-entropy alloy cell skeleton is used to connect to the aluminum substrate, and the pores of the lattice high-entropy alloy cell skeleton are used to fill aluminum-based brazing filler metal.

[0133] Step 51: The workpiece processed in step 4 is clamped and positioned with the aluminum substrate (5052 aluminum alloy). The overlapping area of ​​the aluminum substrate is located on the top surface of the high-entropy alloy transition layer of the aluminum-steel laser brazing lattice, and the clamping gap is 0.06mm.

[0134] Step 52: Using laser brazing equipment and AlSi12 welding wire, focus the laser beam onto the AlSi12 welding wire, set the laser brazing process parameters and proceed with the process (laser brazing process parameters are: laser power 1500W, welding speed 1.5m / min, defocusing amount +3mm, shielding gas is argon, gas flow rate 13L / min). This allows the liquid aluminum brazing filler metal formed by melting the aluminum matrix and AlSi12 welding wire to wet, spread and fill the pores of the lattice high-entropy alloy cell skeleton, and to react with the transition layer and stainless steel at the interface.

[0135] After steps 53 and 52 are completed, the workpiece is allowed to cool naturally to room temperature to obtain a component with a high-entropy alloy transition layer with aluminum-steel laser brazing lattice.

[0136] The performance of the component sample prepared in Example 6 was tested. The results showed that the wetting angle of the aluminum-based brazing filler metal at the welding interface was 21°, the brittle phase at the interface was discretely distributed and there was no continuous layer, the tensile strength of the welded joint reached 412 N / mm, the joint fractured in the aluminum matrix (i.e. the aluminum alloy base material), and the ductile fracture characteristics were obvious.

[0137] In this example, after adopting the in-situ self-supporting strategy and functionally graded lattice design, the tensile strength of the joint was further improved, and the wetting angle was reduced by about 4° (compared to Example 2). The joint was subjected to thermal cycling test (-40℃~150℃, 100 cycles). The residual deformation of the joint in Example 6 was only 35% of that in Example 1, indicating that the functionally graded design more effectively alleviated thermal stress and improved the thermal fatigue performance of the joint. Moreover, there was no mechanical damage on the surface of the lattice skeleton, the pore connectivity was good, and no pillar breakage or node damage caused by support removal occurred.

[0138] In other implementations, the porosity of the lattice high-entropy alloy cell framework can be selected as 60-80%, the pore size as 200-800μm, and the thickness as 0.3-1mm; the optional process conditions during laser processing are: the processing area is protected by argon gas, the laser power is 150W-300W, the scanning speed is 800mm / s-2000mm / s, the layer thickness is 20μm-50μm, the scanning spacing is 50μm-100μm, and the oxygen content is ≤0.1%; the optional parameters for laser brazing process are: laser power 800W-2000W, welding speed 1m / min-3m / min, defocusing amount -5mm-+5mm, the protective gas is argon gas, and the gas flow rate is 10L / min-15L / min.

Claims

1. A laser beam processing method for laser brazing a high-entropy alloy transition layer in an aluminum-steel lattice, characterized by the following steps: include: Step 1: Select FeCoCrNiMn high-entropy alloy powder with a particle size of 15μm~53μm; select stainless steel as the steel matrix, clean it and set it aside. Step 2: Construct a lattice structure model of the high-entropy alloy transition layer for aluminum-steel laser brazing; Step 3: Using a selective laser melting device, FeCoCrNiMn high-entropy alloy powder is laid on a steel substrate. According to the lattice structure model and path planning, the FeCoCrNiMn high-entropy alloy powder is laser-processed to obtain an alloy part with a lattice high-entropy alloy cell skeleton. Step 4: Clean the obtained alloy parts to obtain an aluminum-steel laser brazing lattice high-entropy alloy transition layer; The aluminum-steel laser brazing lattice high-entropy alloy transition layer includes a lattice high-entropy alloy cell skeleton connected to the steel substrate. The porosity of the lattice high-entropy alloy cell skeleton is 60-80%, the pore size is 200-800μm, and the thickness is 0.3-1mm. The upper part of the lattice high-entropy alloy cell skeleton is used to connect to the aluminum substrate, and the pores of the lattice high-entropy alloy cell skeleton are used to fill liquid aluminum brazing filler metal.

2. The laser beam processing method according to claim 1, characterized in that: The type of the high-entropy lattice alloy cell framework is one or more combinations of face-centered cubic structure, body-centered cubic structure, and rhombic dodecahedral structure.

3. The laser beam processing method according to claim 1, characterized in that, The method for cleaning the obtained alloy parts is as follows: high-pressure argon gas is used to blow away the unmelted powder on the workpiece, and sandpaper is used to polish and remove burrs.

4. The laser beam processing method according to claim 1, characterized in that, The process conditions during laser processing are as follows: the processing area is protected by argon gas, the laser power is 150W~300W, the scanning speed is 800mm / s~2000mm / s, the layer thickness is 20μm~50μm, the scanning spacing is 50μm~100μm, and the oxygen content is ≤0.1%.

5. The laser beam processing method according to any one of claims 1-4, characterized in that, The process also includes step 5, which connects the high-entropy alloy transition layer obtained in step 4 to the aluminum substrate via laser brazing. Step 51: The workpiece processed in step 4 is clamped and positioned with the aluminum substrate. The overlapping area of ​​the aluminum substrate is located on the top surface of the high-entropy alloy transition layer of the aluminum-steel laser brazing lattice. The clamping gap is ≤0.1mm. Step 52: Using laser brazing equipment and AISi12 welding wire, focus the laser beam onto the AISi12 welding wire, set the laser brazing process parameters, and then process it so that the liquid aluminum brazing material formed by melting the aluminum matrix and AISi12 welding wire wets, spreads and fills the pores of the lattice high-entropy alloy cell skeleton. After steps 52 and 53 are completed, the workpiece is allowed to cool naturally.

6. The laser beam processing method according to claim 5, characterized in that, The laser brazing process parameters are as follows: laser power 800W~2000W, welding speed 1m / min~3m / min, defocusing amount -5mm~+5mm, shielding gas is argon, and gas flow rate is 10L / min~15L / min.

7. The laser beam processing method according to claim 5, characterized in that, Follow these steps to plan your route: Step 31: Divide the lattice structure model into N forming unit layers along the height direction, where N is a positive integer greater than a preset threshold. Each forming unit layer contains at least one unit cell layer. Based on the unit cell geometric topology, divide the scanning area within each forming unit layer into a unit cell pillar region and a unit cell node region. Step 32: For the unit cell pillar region, the first laser scanning strategy is adopted: the laser beam performs unidirectional continuous scanning along the pillar axis, the scanning speed is greater than the preset speed threshold, and the laser power is adjusted in a gradient according to the pillar cross-sectional size. Thin pillars with cross-sectional sizes smaller than the preset size threshold correspond to lower power, and thick pillars with cross-sectional sizes larger than the preset size threshold correspond to higher power. Step 33: For the unit cell node region, a second laser scanning strategy is adopted: the laser beam performs a ring or cross-shaped scan around the node center, the laser power is higher than the power of the thin pillar region but lower than the power of the coarse pillar region, the scanning speed is lower than the scanning speed of the first laser scanning strategy, and the dwell time is greater than the preset time threshold to ensure that the powder at the node is fully fused. Step 34: Steps 32 and 33 are executed layer by layer in a bottom-up order. The scanning direction between adjacent forming unit layers rotates at a preset angle, which is greater than 0° and less than 180°.

8. The laser beam processing method according to claim 7, characterized in that, Also includes: Step 35: During the scanning process, dynamically identify and mark the cell pillars in the current forming unit layer whose suspended span is greater than the preset span threshold as suspended pillars, and generate an auxiliary support scanning path below the suspended pillars; the laser power of the auxiliary support scanning path is lower than the laser power of the cell pillar region, and the scanning speed is higher than the scanning speed of the cell pillar region, forming a microscale support structure that is metallurgically bonded to the suspended pillars. After completing the main scanning of the current forming unit layer, a supplementary scan is performed according to the auxiliary support scanning path; when the subsequent forming unit layer covers the microscale support structure, the microscale support structure is remelted and fused with the upper cell pillar to form a whole.

9. The laser beam processing method according to claim 1, characterized in that, The steps for constructing a lattice structure model include: Step 21: Obtain the difference in thermal expansion coefficients between the aluminum substrate and the steel substrate and the heat input distribution characteristics of laser brazing, and determine the thermal stress gradient distribution along the thickness direction of the transition layer; Step 22: Based on the thermal stress gradient distribution, the transition layer is divided along the thickness direction into a first functional layer near the steel substrate, an intermediate second functional layer, and a third functional layer near the aluminum substrate. The cell pillar diameter of the first functional layer is greater than a preset diameter threshold and the porosity is lower than a preset porosity threshold to provide a high-strength metallurgical bond with the steel substrate. The cell pillar diameter of the third functional layer is smaller than the preset diameter threshold and the porosity is higher than the preset porosity threshold to enhance the capillary wetting effect of the liquid aluminum solder. The cell pillar diameter and porosity of the second functional layer are between those of the first and third functional layers, forming a thermal stress buffer gradient. Step 23: Each functional layer adopts the same or different cell types, and the cell node positions of adjacent functional layers are aligned or staggered according to a preset offset to ensure the continuity of the interlayer structure.

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