A bimetallic component with interfacial interlocking structure and multi-angle reciprocating remelting additive manufacturing method thereof

Abstract

This invention discloses a bimetallic component with an interlocking interface structure and its multi-angle reciprocating remelting additive manufacturing method, belonging to the field of metal additive manufacturing technology. The method employs multi-material laser powder bed melting technology for forming, including: dividing each forming layer into region A, region B, and an overlap region located at the interlocking interface; first performing a low-energy-density forming scan on region A, then performing a high-energy-density forming scan on region B; subsequently performing at least three laser remelting scans only on the interface overlap region, with adjacent remelting scan directions rotating by a preset angle each time. This invention, through the synergistic effect of the macroscopic interlocking interface structure and the three multi-angle reciprocating selective remelting processes within the same layer, promotes the full mixing and diffusion of dissimilar material elements in the concave and convex parts of the interlocking structure, significantly reducing interface porosity and crack defects, achieving composite strengthening of interface mechanical interlocking and high-quality metallurgical bonding without affecting the properties of the main material.

Description

Technical Field

[0001] This invention belongs to the field of metal additive manufacturing technology, specifically relating to a bimetallic component with an interface interlocking structure and its multi-angle reciprocating remelting additive manufacturing method. Background Technology

[0002] With the increasing demands for comprehensive performance of structural components under high temperature, high load, and complex service environments in aerospace, energy equipment, and high-end manufacturing fields, multi-material structures that combine two or more metallic materials in the same component according to functional requirements are gradually becoming an important development direction. Laser Powder Bed Fusion (LPBF) based multi-material additive manufacturing technology is considered an effective technical approach for preparing dissimilar metal composite components due to its advantages such as high forming accuracy, high material utilization, and the ability to achieve integrated manufacturing of complex structures.

[0003] In existing multi-material laser powder bed melting manufacturing methods, laser scanning is typically performed separately on different material regions within the same forming layer. At the material interface, overlapping or energy compensation methods are used to connect dissimilar materials. While this method can achieve integrated forming of multi-material components to some extent, its interface structure is often macroscopically flat, with the interface region relying primarily on a single forming or a limited number of laser pulses to form a metallurgical bond. Because dissimilar metal materials exhibit significant differences in melting point, thermal conductivity, coefficient of linear expansion, and solidification behavior, the interface region often undergoes rapid heating and cooling processes during the manufacturing process, easily forming large transient temperature gradients. This leads to insufficient material mixing and inadequate metallurgical bonding continuity at the interface. Particularly when the later-formed material covers or connects the earlier-formed material, problems such as molten pool instability can easily occur at the interface, resulting in porosity, incomplete fusion defects, and even microcracks, severely affecting the interface density and service reliability of multi-material components.

[0004] Current technologies primarily focus on adjusting single process parameters such as laser power and scanning speed to control the interface region. They lack a systematic and coordinated design that considers the division of the forming region, the structural form of the interface overlap area, and multiple thermal cycles within the same forming layer. This results in limited room for improvement in interface bonding strength, making it difficult to meet the performance requirements of dissimilar material interfaces under high reliability and multi-condition service conditions. There is an urgent need for a novel additive manufacturing method that can achieve high density and high bonding strength at dissimilar material interfaces through coordinated control of structural design and forming processes. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a bimetallic component with an interlocking interface structure and its multi-angle reciprocating remelting additive manufacturing method, so as to solve the problems of insufficient interface bonding strength, easy generation of interface porosity and crack defects, and obvious anisotropy of interface properties that are common in the existing laser powder bed fusion additive manufacturing process of dissimilar materials.

[0006] To achieve the above objectives, the present invention employs the following technical solution: A multi-angle reciprocating remelting additive manufacturing method for bimetallic components with an interface interlocking structure, characterized by the use of multi-material laser powder bed melting technology for forming, comprising the following steps: S1, within each forming layer, the printing area is divided into a first material A area, a second material B area, and an interface overlap area located at the interface between A area and B area; the interface between A area and B area is a macroscopically non-flat interface interlocking structure. S2, within the same forming layer, laser forming scanning is first performed on area A, and then laser forming scanning is performed on area B, with the laser energy density of area B being greater than that of area A; S3, after completing the forming scans of areas A and B, perform at least three laser remelting scans on the interface overlap area; The three laser remelting scans all adopt a reciprocating scanning method, and between two adjacent remelting scans, the laser scanning direction of the interface overlap area is rotated by a preset angle relative to the scanning direction of the previous remelting scan, so as to promote the mixing and metallurgical bonding of dissimilar material elements at the interface interlocking structure through multi-angle thermal cycling. S4, repeat S2-S3, stacking layer by layer until the entire bimetallic component is printed.

[0007] A further improvement of the present invention is that: Preferably, the first material is 316L stainless steel powder, and the second material is In718 high-temperature alloy powder; The forming process parameters for 316L in area A are: laser power 160W–170W, scanning speed 900mm / s–1000mm / s, and energy density 66.67–78.70J / mm². 3 ; The forming process parameters for In718 in region B are: laser power 210W–215W, scanning speed 950mm / s–1050mm / s, and energy density 83.33–94.30J / mm². 3 .

[0008] Preferably, the process parameters for the three laser remelting scans are: laser power 210W, scanning speed 800mm / s, and scanning spacing 0.08mm.

[0009] Preferably, the rotation angle of the scanning direction between two adjacent remelting scans is 67°.

[0010] Preferably, the geometric shape of the interface interlocking structure includes one or more combinations of sawtooth, wavy, stepped, or polygonal broken line shapes, and the interface overlapping area is continuously distributed along the contour of the interface interlocking structure.

[0011] Preferably, the width d of the interface overlap area is 0.05–1.0 mm.

[0012] Preferably, the scanning path of the three laser remelting scans covers the protruding and recessed parts of the interface interlocking structure, causing periodic disturbances in the molten pool during the remelting process.

[0013] A bimetallic component with an interface interlocking structure is prepared by the multi-angle reciprocating remelting additive manufacturing method described in any of the above claims.

[0014] Preferably, the interface region of the bimetallic component has a continuous metallurgical transition zone formed by three multi-angle reciprocating remelting processes, and the interface porosity is lower than that of the comparative sample that did not use the remelting process.

[0015] Preferably, the interlocking height h of the interface interlocking structure is 1mm–5mm, and the interlocking width w is 1–5mm.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a multi-angle reciprocating remelting additive manufacturing method for bimetallic components with an interlocking interface structure, employing multi-material laser powder bed melting technology to form the bimetallic component. The dissimilar material interfaces of the bimetallic component have an interlocking structure, formed by the interlocking of region A and region B at the interface. Within each forming layer, the printing area is divided into region A, region B, and an interface overlap region located at the interlocking interface. After the initial forming scan of regions A and B, three laser remelting scans are performed only on the interface overlap region. All three remelting scans employ a reciprocating scanning method, and between adjacent remelting scans, the laser scanning direction of the interface overlap region is rotated by 67° relative to the previous remelting scan. Through the synergistic effect of the interlocking interface structure and the three-stage multi-angle reciprocating remelting process, a continuous and stable metallurgical bonding transition zone is formed at the interlocking interface between the dissimilar materials, effectively suppressing interface porosity and crack defects, and significantly improving the bonding strength and structural reliability of the dissimilar material interface. This invention aims to achieve a transformation from a single metallurgical bonding to a composite connection mode of "mechanical interlocking + metallurgical bonding" at the interface of dissimilar materials without significantly increasing the complexity of forming, through the synergistic effect of interface structure design and interface thermal process control. This significantly improves the interface bonding strength and overall service reliability of dissimilar material components.

[0017] The coordinated design of the interlocking interface structure and the interface overlap region provides a stable and controllable strengthening area for the subsequent three-stage remelting process, avoiding adverse effects on the properties of the main material. This invention sets continuously distributed interface overlap regions along the contour of the interlocking interface, ensuring that the three laser remelting scans only act on the interface strengthening area, without repeated heat input to the main A and B regions. This design effectively avoids problems such as grain coarsening and residual stress accumulation caused by overall remelting or large-scale thermal cycling, while ensuring sufficient remelting and strengthening of the interface area, thus achieving a balance between directional strengthening of interface properties and stable forming of the main structure.

[0018] Furthermore, this invention performs three independent laser remelting scans on the interface overlap area within the same forming layer, with the scanning direction rotating sequentially between adjacent remelting scans. This significantly enhances the molten pool disturbance and element mixing at the interface, forming a continuous and stable metallurgical transition zone. The multi-angle reciprocating scanning method causes the molten pool in the interface region to repeatedly form, collapse, and resolidify in different directions, significantly enhancing the convection behavior inside the molten pool. This promotes thorough mixing and element diffusion of 316L and In718 at the interlocking structural uneven parts. Compared with single remelting or repeated scanning in the same direction, this invention can form a more uniform and continuous metallurgical bonding transition zone at the interface, effectively reducing the risk of abrupt compositional changes and brittle phase enrichment.

[0019] Furthermore, the triple remelting process introduces multiple controlled thermal cycles within the same formed layer, effectively reducing the transient temperature gradient at the interface and suppressing the formation of porosity and incomplete fusion defects. Due to significant differences in melting point, thermal conductivity, and coefficient of linear expansion between 316L and In718, the interface region is prone to large transient temperature gradients in traditional forming processes, thereby inducing porosity, incomplete fusion, and even microcrack defects. This invention, by introducing three multi-angle remelting processes in the interface overlap area, allows the interface region to undergo multiple gentle heating and cooling processes, reducing the degree of thermal shock and significantly improving interface density and structural integrity.

[0020] The second aspect of this invention discloses a bimetallic component with an interlocking interface structure. Unlike the macroscopically flat interface commonly used in existing multi-material laser powder bed melting technology, this invention introduces an interlocking interface structure with periodic undulations in the connection region of 316L and In718, enabling the two dissimilar materials to form a spatial embedding relationship at the interface. This interlocking structure effectively disperses stress concentration when the interface is under load, significantly improving the interface's shear and peel resistance. Simultaneously, the interlocking structure provides a larger effective contact area and multi-directional load-bearing paths for the interface region, making the interface bonding no longer solely dependent on metallurgical diffusion, thus improving the overall reliability of the dissimilar material interface from a structural perspective. Attached Figure Description

[0021] Figure 1This is a model diagram of the present invention; Figure 2 A schematic diagram of the partitions within each forming layer; Figure 3 This is a schematic diagram of the three-stage remelting scan path; Figure 4 A schematic diagram showing the dimensions of each interlocking interface; Figure 5 This is a flowchart of the process for preparing the components according to the present invention; Figure 6 The image shown is an optical micrograph of the sample prepared using the present invention in Example 1. Figure 7 This is an optical micrograph of the sample prepared using the present invention in Example 2. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings: To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0023] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0024] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0025] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0026] See Figures 1-3To achieve high-density and high-bonding-strength interface bonding of dissimilar metal materials in laser powder bed fusion additive manufacturing, this invention proposes a dissimilar material additive manufacturing technology that combines an interface interlocking structure design with a three-stage multi-angle reciprocating remelting scanning process.

[0027] See Figure 3 A bimetallic component is formed using multi-material laser powder bed melting technology. The bimetallic component includes a first material region A and a second material region B, with different material systems. Regions A and B form an interlocking structure at the interface between the first and second materials. This interlocking structure is a macroscopically non-flat interface formed at the interface between the two materials. Within each forming layer, the printing area is divided into region A, region B, and an interface overlap area located at the interlocking structure. Within the same forming layer, region A (with lower energy density) is first laser-scanned, followed by region B (with higher energy density). Laser forming scanning is performed, with the energy density of region B being greater than that of region A, allowing region A to remelt during the printing of region B. After completing the forming scans of regions A and B, three laser remelting scans are performed only on the interface overlap area. Each of the three laser remelting scans employs a reciprocating laser scanning method, and between adjacent remelting scans, the laser scanning direction of the interface overlap area is rotated 67° relative to the previous remelting scan. This enhances the mixing degree of dissimilar materials at the interface interlocking structure, reduces the temperature gradient at the interface, and thus strengthens the metallurgical bonding strength at the interface.

[0028] See Figure 4The interface interlocking structure is periodically distributed on the component, and its geometric shape includes, but is not limited to, one or more combinations of sawtooth, wave, stepped, or polygonal broken line shapes. The characteristic parameters of the interface interlocking structure include interlocking height h, interlocking width w, and interlocking period p. The interlocking height h refers to the undulation amplitude of the interface interlocking structure in the direction perpendicular to the interface (interface normal), i.e., the depth of material A embedded in material B; preferably, the interlocking height h is 1mm–5mm. The interlocking width w is the lateral dimension of a single periodic structure (such as a sawtooth or a wave) of the interface interlocking structure in the direction parallel to the interface (usually within the forming plane), i.e., a complete interlocking unit of 1–5mm. The interlocking period refers to the minimum distance at which the interface interlocking structure repeats along the extension direction of the interface, i.e., the length between two adjacent identical interlocking features; the interlocking width is less than the interlocking period. The interface overlap area width d refers to the width of the area extending to both sides along the outline of the interface interlocking structure within each forming layer. This region covers the protruding and recessed parts of the interlocking structure, specifically designed to support subsequent multiple laser remelting scans. Preferably, the interface overlap area is 0.05–1.0 mm wide, and this overlap area is continuously distributed along the contour of the interlocking interface structure. At the interlocking interface location, an interface overlap area of ​​width d is set along the interface contour. This overlap area continuously covers the protruding and recessed parts of the interlocking structure, serving to support subsequent multiple laser remelting scans. Through this design, the interface region not only possesses a metallurgical connection foundation but also exhibits certain mechanical interlocking characteristics, providing a structural prerequisite for subsequent remelting strengthening.

[0029] The three laser remelting scans are applied only to the interface overlap area, without remelting the main body in area A and area B, to avoid adversely affecting the forming quality of the main body area. The molten pool formed during the three remelting scans undergoes periodic disturbance at the interlocking structure of the interface, thereby promoting convective mixing and element diffusion of the two dissimilar metals in the interlocking concave-convex region.

[0030] Furthermore, the triple multi-angle reciprocating remelting process is used to alleviate the residual stress concentration at the interface caused by differences in the thermal properties of the materials. The interfacial interface formed by the interlocking structure and the triple multi-angle reciprocating remelting process results in a lower porosity in the interfacial region compared to the control sample that did not undergo the remelting process.

[0031] See Figure 5 In a specific example, the dissimilar material with the interface interlocking structure is a 316L / In718 bimetallic component; the 316L / In718 dissimilar material with the interface interlocking structure is printed by the following specific steps: S1, Modeling and partitioning of interface interlocking structure and overlapping area Based on the service conditions and interface load-bearing requirements of the bimetallic components, a macroscopically non-straight interface interlocking structure is pre-designed in the connection area between 316L and In718. The interlocking structure is periodically distributed on the forming plane (XY plane), and its geometry can be sawtooth, wavy, or stepped, so that the 316L area and the In718 area form an interlocking spatial structure on a macroscopic scale.

[0032] At the interlocking interface, an interface overlap area of ​​width d is set along the interface contour. This overlap area continuously covers the protrusions and recesses of the interlocking structure to support subsequent multiple laser remelting scans. Through this design, the interface area not only has a metallurgical connection foundation but also possesses certain mechanical interlocking characteristics, providing a structural prerequisite for subsequent remelting and strengthening.

[0033] S2, Forming preparation and process parameter configuration S21. Use Solidworks to perform independent geometric modeling of area A (316L) and area B (In718), import the model into the slicing software Magics, place the geometric model on the printer platform, pre-design a macroscopic non-straight interface interlocking structure in the connection area between areas A and B, and embed the area B model along the X direction with a width d to form an overlap area.

[0034] S22, Model slice parameters: slice thickness 0.03mm, spot compensation 0, output format SLC; S23: Import the SLC file into the printing device, configure the process packages and corresponding powders for areas A and B, parse and generate the printing path, and simulate and verify it. Configure the process packages and powders for the models in areas A and B. After the process packages and powders are configured, click the "Path" button to parse the slice file and generate the path. Perform a simulated print to observe for any errors.

[0035] S24, Powder selection: 316L and In718 powders with a particle size of 15-53μm, respectively loaded into the corresponding powder tanks; S25, substrate leveling, using a steel substrate, until powder can be evenly spread horizontally on the substrate, close the forming chamber and evacuate to reduce the oxygen content to below 0.01%, then turn on the laser to prepare for printing.

[0036] S3, Region division within the forming layer and initial forming scan Within each forming layer, the printing area is clearly divided into: area A (316L forming area), area B (In718 forming area), and interface overlap area (between areas A and B, continuously distributed along the interlocking interface contour).

[0037] S31, 316L powder is dropped into powder cylinder A. After the powder is spread, the A area is melted by laser. After completion, the 316L powder in the non-A area is removed by powder suction and powder replacement operation. S32, In718 powder is dropped into powder cylinder B, and the B region is melted by laser after powder spreading; this scanning sequence causes the forming process of the In718 region to generate secondary heat input to the adjacent 316L region, forming a thermal state in the interface region that is conducive to subsequent remelting, while avoiding interference of the molten pool caused by simultaneous forming.

[0038] The specific process parameters are as follows: 316L (Area A): Laser power 160W-170W, scanning speed 900mm / s-1000mm / s, scanning spacing 0.08mm, layer thickness 0.03mm, interlayer rotation 67°, energy density 66.67~78.70J / mm² 3 ; In718 (B Zone): Laser power 210W-215W, scanning speed 950mm / s-1050mm / s, scanning spacing 0.08mm, layer thickness 0.03mm, interlayer rotation 67°, energy density 83.33~94.30J / mm² 3 .

[0039] In the above process, within the same forming layer, the 316L powder in region A is first laser-scanned and formed using process parameters with lower energy density to create a stable molten pool and complete the initial solidification. Subsequently, the In718 powder in region B is laser-scanned and formed using process parameters with higher energy density to compensate for the effects of In718's higher melting point and lower molten pool fluidity. This scanning sequence ensures that the subsequently formed In718 region, near the interface, can generate a certain amount of heat input to the already formed 316L region, laying the thermal foundation for the subsequent remelting and element diffusion of the interface region.

[0040] S4, three-stage multi-angle reciprocating remelting scan of the interface overlap area. After the initial forming of areas A and B is completed, no secondary processing is performed on the main body area. Only the interface overlap area is remelted three times. The remelting energy density is higher than the initial forming parameters of areas A and B to ensure complete melting. The scanning method is reciprocating, and the direction of adjacent scanning is rotated by 67°.

[0041] S41, First remelting (interface remelting and initial mixing): Scanning back and forth along the preset direction to remelt the NEIDE316L and In718 materials in the overlapping area as a whole, eliminating the defect of incomplete fusion, and promoting the initial connection of the two materials in the interlocking structure's concave and convex parts; forming a continuous melting channel in the interface area.

[0042] S42, Second Remelting (Multi-directional Disturbance and Strengthening Mixture): The second remelting scan still uses a reciprocating scanning method, but its scanning direction is rotated 67° relative to the first remelting scan direction. Due to the change in scanning direction, the heat flow direction inside the molten pool and the Marangoni convection path change significantly, causing cross-disturbance in the molten pool at the interlocking structure. In this stage: the molten pool forms a multi-directional circulating flow in the recessed area of ​​the interlocking structure; promotes elemental diffusion and compositional homogenization of 316L and In718 at the interface; effectively weakens the transient temperature gradient at the interface and alleviates thermal stress concentration.

[0043] S43, Third Remelting (Defect Repair and Microstructure Stabilization): The scanning direction of the third remelting scan is rotated by 67° from the second scan, resulting in multi-angle coverage of the interface overlap area. This stage is mainly used for: re-fusion of any micropores that may remain after the first two remeltings; promoting the formation of a continuous and stable metallurgical transition zone in the interface region through multiple thermal cycles; and achieving a composite interface morphology of "mechanical interlocking + metallurgical bonding" within the interlocking structure. Through the synergistic effect of three multi-angle reciprocating remelting scans, the interface overlap area undergoes multiple controlled thermal cycles within the same forming layer, while the main body area remains unaffected, thereby achieving directional enhancement of interface performance without significantly increasing the overall forming heat input.

[0044] Remelting process parameters: laser power 210W, scanning speed 800mm / s, scanning spacing 0.08mm, layer thickness 0.03mm.

[0045] S5, layer-by-layer repeated forming and component completion Repeat steps S31-S43 above, including powder spreading, A / B area forming, and three remelting steps for the overlapping area, stacking layers one by one until the entire bimetallic component is printed. After cooling, the substrate is separated by electrical discharge wire cutting, and the sample is ultrasonically cleaned. The printing of a 316L / In718 bimetallic component with multiple remelting of the overlapping area with interlocking interfaces is completed in several steps.

[0046] The 316L powder contains 0.018 wt% C, 0.52 wt% Si, 1.36 wt% Mn, 0.021 wt% P, 0.005 wt% S, 13.57 wt% Ni, 18.19 wt% Cr, 2.60 wt% Mo, 0.022 wt% O, 0.069 wt% N, with the balance being Fe.

[0047] The In718 powder contains 0.041 wt% C, 0.041 wt% Si, 0.012 wt% Mn, 0.004 wt% P, 0.0006 wt% S, 54.12 wt% Ni, 18.92 wt% Cr, 2.98 wt% Mo, 5.31 wt% Nb, 0.1 wt% Co, 0.011 wt% Cu, 0.68 wt% Al, 0.005 wt% B, 0.001 wt% Mg, 1.12 wt% Ti, 0.0081 wt% O, 0.0026 wt% N, with the balance being Fe.

[0048] The following description, in conjunction with specific embodiments, provides further details.

[0049] Example 1 In this embodiment, the material of area A is 316L, the material of area B is In718, and the interface interlocking shape is concave-convex. It is formed through the following steps: (1) Select 316L and In718 as materials, design the interlocking shape of the interface as concave-convex type, and set the overlap area width to 0.1mm.

[0050] (2) For example Figure 1 As shown, Solidworks was used to model several structures of 316L and In718 respectively, and after the modeling was completed, the models were exported.

[0051] (3) Import the file exported in step (2) into the slicing software Magics to place the model and perform slicing operations. Embed the two models 0.1mm according to the preset overlap width. After the model is placed, perform slicing operations with a layer thickness of 0.03mm, a spot compensation of 0mm, and output in SLC format.

[0052] (4) Import the sliced ​​file into the printer's computer system, and then load the model.

[0053] (5) After the model is loaded, select the 316L geometric model to configure the process package, where the laser power is 170W and the scanning speed is 1000mm / s. Select the In718 geometric model to configure the process package, where the laser power is 215W and the scanning speed is 1050mm / s. Select the remelting region to configure the process, with a laser power of 210W and a scanning speed of 800mm / s.

[0054] (6) After the process package is configured, select all 316L geometry models for powder configuration and configure them as 316L powder; select all In718 geometry models for powder configuration and configure them as In718 powder.

[0055] (7) After configuration, click the "Path" button to parse the sliced ​​file and generate the path. Perform a simulated print to observe for errors. (8) After confirming that everything is correct, put the 316L powder into powder tank 1 and the In718 powder into powder tank 2. The 316L powder contains 0.018wt% C, 0.52wt% Si, 1.36wt% Mn, 0.021wt% P, 0.005wt% S, 13.57wt% Ni, 18.19wt% Cr, 2.60wt% Mo, 0.022wt% O, 0.069wt% N, and the balance is Fe. The process parameters for 316L are: laser power 160W-170W, scanning speed 900mm / s-1000mm / s, scanning interval 0.08mm, layer thickness 0.03mm, interlayer rotation 67°, and laser energy density 66.67~78.70J / mm. 3 The In718 powder contains 0.041 wt% C, 0.041 wt% Si, 0.012 wt% Mn, 0.004 wt% P, 0.0006 wt% S, 54.12 wt% Ni, 18.92 wt% Cr, 2.98 wt% Mo, 5.31 wt% Nb, 0.1 wt% Co, 0.011 wt% Cu, 0.68 wt% Al, 0.005 wt% B, 0.001 wt% Mg, 1.12 wt% Ti, 0.0081 wt% O, 0.0026 wt% N, with the balance being Fe. (9) Level the substrate until a horizontal and uniformly thick powder can be laid on the substrate.

[0056] (10) Close the door of the forming chamber, perform a gas washing operation, and fill it with inert gas Ar until the oxygen content concentration drops to 0.01%.

[0057] (11) Turn on the laser and start printing.

[0058] (12) Powder cylinder 1, containing 316L powder, dispenses powder. After powder dispensing, a powder spreading cart spreads powder, and a layer of 316L powder is laid on the substrate. The laser then melts the 316L powder in area A. After printing the 316L powder in area A, the powder suction shaft removes the 316L powder from area B and the powder spreading cart's trajectory. Then, powder cylinder 2 dispenses In718 powder, the powder spreading cart spreads powder, and the laser melts the In718 powder in area B. Subsequently, the overlapping area between areas A and B undergoes three remelting processes. The energy density used during remelting is 210W, and the scanning speed is 800mm / s to ensure complete melting. The scanning directions for the three remelting processes are different, such as... Figure 3 As shown, the second remelting scan direction is rotated 67° from the first remelting, and the third remelting scan direction is rotated 67° from the second remelting. At this time, the printing of area A and area B of the first forming layer and the remelting of the overlapping area are completed.

[0059] (13) Repeat step (12) until printing is complete, thus obtaining a 316L / In718 bimetallic component with an interface interlocking structure.

[0060] (14) After the molding is completed and cooled, the sample and the substrate are separated by electrical discharge wire cutting process, and the sample is ultrasonically cleaned at the same time.

[0061] (15) Grind and polish according to the metallographic preparation method, and observe the interface under a metallographic microscope. Figure 6 As shown.

[0062] Observe the metallographic micrograph of Example 1, as follows Figure 5 As shown, it can be observed that 316L and In718 exhibit strong mixing at the interface, resulting in good metallurgical bonding and fewer cracks and pores. The method of this invention can reduce residual stress at the interface and decrease cracks and pores, thereby achieving the goal of improving overall mechanical properties.

[0063] Example 2 The basic steps of Example 2 are exactly the same as those of Example 1, the only difference being the geometry of the interface interlock. In this example, the interface interlock geometry is triangular. It is ground and polished according to metallographic preparation methods, and the interface is observed under a metallographic microscope. Figure 7 As shown.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for multi-angle reciprocating remelting additive manufacturing of bimetallic components with an interface interlocking structure, characterized in that, The forming process employs multi-material laser powder bed melting technology, including the following steps: S1, within each forming layer, the printing area is divided into a first material A area, a second material B area, and an interface overlap area located at the interface between A area and B area; the interface between A area and B area is a macroscopically non-flat interface interlocking structure. S2, within the same forming layer, laser forming scanning is first performed on area A, and then laser forming scanning is performed on area B, with the laser energy density of area B being greater than that of area A; S3, after completing the forming scans of areas A and B, perform at least three laser remelting scans on the interface overlap area; The three laser remelting scans all adopt a reciprocating scanning method, and between two adjacent remelting scans, the laser scanning direction of the interface overlap area is rotated by a preset angle relative to the scanning direction of the previous remelting scan, so as to promote the mixing and metallurgical bonding of dissimilar material elements at the interface interlocking structure through multi-angle thermal cycling. S4, repeat S2-S3, stacking layer by layer until the entire bimetallic component is printed.

2. The multi-angle reciprocating remelting additive manufacturing method for a bimetallic component with an interface interlocking structure according to claim 1, characterized in that, The first material is 316L stainless steel powder, and the second material is In718 high-temperature alloy powder; The forming process parameters for 316L in area A are: laser power 160W–170W, scanning speed 900mm / s–1000mm / s, and energy density 66.67–78.70J / mm². 3 ; The forming process parameters for In718 in region B are: laser power 210W–215W, scanning speed 950mm / s–1050mm / s, and energy density 83.33–94.30J / mm². 3 .

3. A multi-angle reciprocating remelting additive manufacturing method for a bimetallic component with an interface interlocking structure according to claim 1 or 2, characterized in that, The process parameters for the three laser remelting scans are: laser power 210W, scanning speed 800mm / s, and scanning interval 0.08mm.

4. The multi-angle reciprocating remelting additive manufacturing method for a bimetallic component with an interface interlocking structure according to claim 1, characterized in that, The rotation angle of the scanning direction between two adjacent remelting scans is 67°.

5. The multi-angle reciprocating remelting additive manufacturing method for a bimetallic component with an interface interlocking structure according to claim 1, characterized in that, The geometric shape of the interface interlocking structure includes one or more combinations of sawtooth, wave, stepped, or polygonal broken line shapes, and the interface overlapping area is continuously distributed along the outline of the interface interlocking structure.

6. The multi-angle reciprocating remelting additive manufacturing method for a bimetallic component with an interface interlocking structure according to claim 1, characterized in that, The width d of the interface overlap area is 0.05–1.0 mm.

7. The multi-angle reciprocating remelting additive manufacturing method for a bimetallic component with an interface interlocking structure according to claim 1, characterized in that, The scanning paths of the three laser remelting scans cover the protruding and recessed parts of the interface interlocking structure, causing periodic disturbances in the molten pool during the remelting process.

8. A bimetallic component with an interface interlocking structure, characterized in that, It is prepared by the multi-angle reciprocating remelting additive manufacturing method as described in any one of claims 1 to 7.

9. The bimetallic component with an interface interlocking structure according to claim 8, characterized in that, The interface region of the bimetallic component has a continuous metallurgical transition zone formed by three multi-angle reciprocating remelting processes, and the interface porosity is lower than that of the comparative sample that did not use the remelting process.

10. The bimetallic component with an interface interlocking structure according to claim 8, characterized in that, The interlocking height h of the interface interlocking structure is 1mm–5mm, and the interlocking width w is 1–5mm.

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