Thin-walled double-layered dissimilar metal by laser penetration strip 3D printing and method

Abstract

The application discloses a kind of laser penetration strip 3D printing thin-walled double-layer heterogeneous metal and method, belong to metal material processing technical field.The application combines optical fiber laser and multi-degree-of-freedom strip feeding system, when laser beam penetrates heterogeneous layered metal (A metal strip and B metal strip), liquid metal in the laser molten pool formed is acted on by surface tension caused by temperature gradient and vapor jet friction force in penetration keyhole together to generate relatively independent vortex, so that the upper and lower parts of laser molten pool molten metal are kept relatively independent respectively, and layered molten pool is formed;Then, under the condition of larger temperature and concentration gradient, molten pool rapidly solidifies, so that the composition and organization after solidification are in layered state;Micro-flow and material transport characteristics in heterogeneous layered molten pool formed by laser penetration metal material can solve the mutual mixing and diffusion behavior of heterogeneous melt in conventional laser 3D printing technology, and can realize the structure and function integration of thin-walled double-layer heterogeneous metal material.

Description

Technical Field

[0001] This invention belongs to the field of metal material processing technology, specifically relating to a method for laser-through strip 3D printing of thin-walled double-layer heterogeneous metal. Background Technology

[0002] Currently, high-end equipment in modern industries such as aerospace, power, petrochemicals, and shipbuilding is rapidly developing towards larger scale, higher parameters, high reliability under extreme conditions, and longer service life. This places increasingly stringent demands on structural materials, including ultra-high load-bearing capacity, extreme corrosion resistance, ultra-high precision, ultra-lightweight construction, and customized manufacturing. Inspired by the skeletal structure of bird wings and the structure of seashells in nature, metallic materials are being fabricated into thin-walled single / double-layer components, thus giving them lightweight, compact structures, and excellent comprehensive performance. Compared with thin-walled single-layer metallic materials, thin-walled bi-layer dissimilar metals (TBDM) combine the physical, chemical, mechanical, and chemical properties of the component metals, significantly improving the material's strength, stiffness, impact load resistance, and corrosion resistance. Simultaneously, while ensuring structural performance and service life, thin-walled bi-layer components can save on rare and precious metal materials, effectively reducing manufacturing costs. They have wide applications in key structural and functional components in aerospace, nuclear industry, intelligent vehicles, chemical and new energy fields.

[0003] Based on interfacial bonding theories such as mechanical interlocking, metallic bonding, thin films, recrystallization, and the three-stage physical-chemical-diffusion process, the fabrication of thin-walled bilayer heterogeneous metals typically employs methods such as explosive bonding, rolling bonding, deposition bonding, and hot-press diffusion. These traditional fabrication techniques offer advantages in preparing regular profiles, such as shortening production cycles and reducing manufacturing costs. However, they suffer from problems like cracking, delamination, and welding difficulties during the subsequent processing of complex components. Furthermore, during service, multiple types of damage and failure behaviors may occur, including liner collapse, transverse cracks, delamination, interlayer corrosion cracking, and brittle fracture. As thin-walled bilayer heterogeneous metal components continue to upgrade, moving towards larger dimensions, ultra-thinner profiles, greater complexity, personalization, and high-performance components, there is an urgent need to develop shape-controllable fabrication technologies for structurally and functionally integrated thin-walled bilayer metal materials.

[0004] Laser 3D printing is a technology that uses laser heat to melt a substrate, creating high-performance, complex single-layer thin-walled metal components through a layer-by-layer manufacturing process. By utilizing a highly concentrated laser heat source to form a small molten pool, it achieves a lower minimum wall thickness limit compared to other heat source 3D printing technologies. Simultaneously, it allows for the selection of lower heat source power, reducing heat accumulation and temperature gradients, thereby minimizing excessive flow and collapse caused by the melting of thin-walled parts, and mitigating warping and cracking. This gives laser 3D printing a unique advantage in the fabrication of thin-walled structures and brings hope for the development of key technologies for thin-walled metal material preparation.

[0005] However, conventional laser 3D printing technology applied to TBDM forming and preparation still has problems such as deformation and collapse during processing, melt mixing, low processing efficiency, precise pre-positioning of heterogeneous materials, and high cost of recycling heterogeneous powder materials, which cannot meet the preparation requirements. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the present invention aims to provide a method for laser-penetrating strip 3D printing of thin-walled double-layer heterogeneous metals, which solves the technical problems of deformation and collapse, melt mixing, low processing efficiency, precise pre-positioning of heterogeneous materials, and high cost of recycling heterogeneous powder materials in existing 3D printing methods during TBDM forming.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] This invention discloses a method for 3D printing thin-walled bilayer heterogeneous metals using laser-penetrating strips, comprising the following steps:

[0009] S1: Perform part modeling and 3D model data processing. Use software to slice and layer the geometric model of the designed thin-walled double-layer heterogeneous metal part to generate corresponding printing data; confirm the placement and orientation of the part, set printing parameters, and generate the printing program based on the printing data using slicing software.

[0010] S2: Metal strips A and B are fed into the laser heat source of the 3D printing equipment through the strip feeding system and fed into the laser heat source along the set path, where they are tightly bonded. At the same time, the laser beam at the laser heat source moves along the set path and penetrates the thickness direction of metal strips A and B to form a molten pool. After solidification, mechanical interlocking and metallurgical bonding of metal strips A and B are achieved. After the printing process is completed, a thin-walled double-layer heterogeneous metal finished part is obtained.

[0011] The feeding speed of the A metal strip and the B metal strip is the same as the moving speed of the laser beam; there is an angle between the laser beam and the normal of the A metal strip and the B metal strip along the thickness direction.

[0012] Furthermore, a geometric model of the thin-walled double-layer heterogeneous metal finished product is constructed using software, and the path of the laser beam and the strip feeding system in the 3D printing equipment is planned according to the geometric model; the laser beam is generated by a fiber laser.

[0013] Furthermore, the angle between the laser beam and the normals of the A and B metal strips along the thickness direction is 35° to 90°; the feeding speed of the A and B metal strips and the moving speed of the laser beam are both 10 to 1000 cm / min.

[0014] Furthermore, the laser beam has a beam size of 0.01–5 mm, an energy of 100–8000 W, and a defocusing amount of -2–5 mm.

[0015] Furthermore, the molten pool is a double vortex molten pool; in S2, positive protection and back protection are achieved in an argon atmosphere, the flow rate of the positive protection argon is 8-45 L / min, and the flow rate of the back protection argon is 8-45 L / min.

[0016] Furthermore, the materials of the A metal strip and the B metal strip are different kinds of mutually soluble metals; the material of the A metal strip is a nickel-based alloy, titanium alloy, aluminum alloy or magnesium alloy metal-based composite material; the material of the B metal strip is a nickel-based alloy, titanium alloy, aluminum alloy or magnesium alloy metal-based composite material; the thickness of the A metal strip and the B metal strip is 0.1 to 10 mm and the width is 1 to 25 mm.

[0017] Furthermore, the material of the A metal strip is steel, copper, or aluminum; the material of the B metal strip is steel, copper, or aluminum.

[0018] Furthermore, the strip feeding system enables multi-degree-of-freedom constraints on metal strips A and B.

[0019] The present invention also discloses a thin-walled bilayer heterometallic material prepared by the above preparation method.

[0020] Furthermore, the cross-sectional morphology of the thin-walled double-layer heterogeneous metal is a sandwich structure of "metal A - intermediate gradient layer - metal B".

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention discloses a method for 3D printing thin-walled double-layered heterogeneous metals using laser-penetrated strips. When a laser beam penetrates heterogeneous layered metals (metal strip A and metal strip B), the liquid metal in the resulting molten pool is subjected to surface tension caused by the temperature gradient and frictional force from the vapor jet in the penetration keyhole, generating relatively independent eddies. This causes the heterogeneous molten metals in the laser-penetrated pool to be in a layered state. Subsequently, the molten pool rapidly solidifies under a large temperature and concentration gradient, resulting in the composition and structure of the solidified zone maintaining a layered distribution. The microflow and mass transport characteristics within the laser-penetrated heterogeneous layered molten pool can solve the melt mixing behavior in conventional laser 3D printing technology, enabling the integrated additive fabrication of thin-walled double-layered heterogeneous metal materials that combine structure and function. Furthermore, the method disclosed in this invention uses heterogeneous metal strips as the substrate. Compared to metal powders and wires, strips possess self-supporting and constraining capabilities, resisting deformation and collapse during processing. Secondly, the double-layer metal strip has certain longitudinal and transverse dimensions, and laser penetration requires a large laser beam energy, both of which can improve the processing efficiency of TBDM. Furthermore, the double-layer heterogeneous metal strip allows for precise pre-positioning of heterogeneous materials. Finally, using the strip eliminates the need for extensive powder spreading and avoids mixing of heterogeneous substrates, significantly reducing material costs. The laser-penetrating strip 3D printing method for thin-walled double-layer heterogeneous metal disclosed in this invention provides a novel approach to solving the bottleneck problem of integrated forming 3D printing technology for double-layer heterogeneous thin-walled metal, and has broad application prospects.

[0023] The present invention also discloses a thin-walled double-layer heterogeneous metal prepared by the above preparation method. The microstructure of the thin-walled double-layer structure is a sandwich structure of "metal A-intermediate gradient layer-metal B", which has good mechanical properties and corrosion resistance. In addition, it can avoid the risk of collapse and cracking caused by excessive heat accumulation during the printing process when the laser penetrates the strip. It is efficient and has good forming quality. Attached Figure Description

[0024] Figure 1 This is a schematic diagram illustrating the principle of the laser-penetrating strip 3D printing method for thin-walled double-layer heterogeneous metal disclosed in this invention.

[0025] Figure 2 This is a schematic diagram of the macroscopic structure of the thin-walled bilayer heterometallic material prepared in this invention at point A.

[0026] Wherein: aI region; b-II region;

[0027] Figure 3 To demonstrate the laser-penetrating strip printing of a thin-walled, double-layered heterogeneous metal double-vortex molten pool and its post-solidification morphology;

[0028] Among them: a, b - observation of temperature field and flow behavior of double vortex molten pool; c, d - morphology and microstructure of layered heterogeneous metal materials obtained by single-layer printing. Detailed Implementation

[0029] 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.

[0030] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0031] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0032] 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.”

[0033] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0034] like Figure 1 As shown, the present invention discloses a method for 3D printing thin-walled bilayer heterogeneous metal using laser-penetrating strips, comprising the following steps:

[0035] First, part modeling and 3D model data processing are performed. The designed thin-walled double-layer heterogeneous metal finished part is sliced ​​and layered using software to generate corresponding printing data. The placement and orientation of the part are confirmed, printing parameters are set, and the printing program is generated using slicing software based on the printing data.

[0036] Subsequently, metal strips A and B are fed into the laser heat source of the 3D printing equipment through a multi-degree-of-freedom strip feeding system according to a set path and are tightly bonded together. At the same time, the laser beam at the laser heat source moves along a set path and penetrates the thickness direction of metal strips A and B to form a laser molten pool. After solidification, mechanical interlocking and metallurgical bonding of metal strips A and B are achieved. After the printing process is completed, a thin-walled double-layer heterogeneous metal part is obtained. The laser beam and the strip feeding system move simultaneously according to the planned path. The strip feeding speed is consistent with the laser beam moving speed.

[0037] Preferably, a fiber laser printing system is used to provide the laser beam.

[0038] Preferably, the strip feeding system is a multi-degree-of-freedom strip feeding system, and during the printing process, metal strip A and metal strip B should be closely attached at the laser heating distance.

[0039] Preferably, during printing, software is used to construct the geometric model of the thin-walled double-layer heterogeneous metal finished product and to plan the path of the laser beam and strip feeding system.

[0040] Preferably, the strip feeding speed is consistent with the laser beam moving speed, and the walking speed is 10-1000 cm / min.

[0041] Preferably, the laser beam needs to penetrate the tightly bonded A metal strip and B metal strip.

[0042] Preferably, the printing process requires argon gas for both positive and back protection, with the laser positive protection gas flow rate at 8-45 L / min and the back protection gas flow rate at 8-45 L / min.

[0043] Preferably, metal strip A and metal strip B are mutually soluble metals, including nickel-based alloys, titanium alloys, steel, copper, aluminum and aluminum alloys, and magnesium and magnesium alloy metal matrix composites.

[0044] Preferably, the thickness of metal strip A or metal strip B is 0.1 to 10 mm and the width is 1 to 25 mm.

[0045] Preferably, during layer printing, the metal strip portion of the single-layer printing melts, while the unmelted portion melts during the printing of the next layer. The width of the single-layer melting is 0.1–5 mm, and the width of the unmelted portion is 0.1–5 mm.

[0046] Preferably, the laser beam direction can be horizontal or vertical.

[0047] Preferably, the angle between the laser beam and the normals of the two different metal strips along the thickness direction is 35° to 90°.

[0048] Preferably, the laser beam has a beam size of 0.01–10 mm, an energy of 100–8000 W, and a defocusing amount of -2–5 mm; the laser molten pool is a double eddy current molten pool.

[0049] 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.

[0050] 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.

[0051] Example 1

[0052] A method for 3D printing thin-walled bilayer heterogeneous metals using laser-penetrating strips includes the following steps:

[0053] S1: Perform part modeling and 3D model data processing. Use software to slice and layer the designed thin-walled double-layer heterogeneous metal finished part to generate corresponding printing data; confirm the placement and orientation of the part, set printing parameters, and generate the printing program through slicing software based on the printing data.

[0054] S2: A 2mm thick and 6mm wide Q235 steel strip (metal strip A) and a 2mm thick and 5mm wide 304L stainless steel strip (metal strip B) are fed into the laser heat source of the 3D printing equipment through a strip feeding system along a set path and fit tightly together. At the same time, the laser beam at the laser heat source moves along a set path and forms a 90° angle with the normal of the thickness direction of the Q235 steel strip and the 304L stainless steel strip, penetrating the thickness direction of the Q235 steel strip and the 304L stainless steel strip to form a molten pool. After solidification, the Q235 steel strip and the 304L stainless steel strip achieve mechanical interlocking and metallurgical bonding. After the printing process is completed, a thin-walled double-layer heterogeneous metal finished part with a thickness of 3.6mm and a height of 170mm is obtained.

[0055] The feed speed of Q235 steel strip and 304L stainless steel strip is the same as the moving speed of the laser beam, both being 150cm / min. Argon gas is used for front and back protection during the printing process, with a laser front protection gas flow rate of 15L / min and a back protection gas flow rate of 25L / min. The laser beam is generated by a fiber laser, with a beam spot size of 0.2mm, an energy of 3200W, and a defocusing amount of 0mm.

[0056] Example 2

[0057] A method for 3D printing thin-walled bilayer heterogeneous metals using laser-penetrating strips includes the following steps:

[0058] S1: Perform part modeling and 3D model data processing. Use software to slice and layer the designed thin-walled double-layer heterogeneous metal finished part to generate corresponding printing data; confirm the placement and orientation of the part, set printing parameters, and generate the printing program through slicing software based on the printing data.

[0059] S2: An Incoloy 800 nickel-based alloy strip (metal strip A) with a thickness of 1mm and a width of 3mm and a 316L stainless steel strip (metal strip B) with a thickness of 1mm and a width of 3mm are fed into the laser heat source of the 3D printing equipment through the strip feeding system according to the set path and fit tightly together. At the same time, the laser beam at the laser heat source moves according to the set path and forms a 90° angle with the normal of the Incoloy 800 nickel-based alloy strip and the 316L stainless steel strip along the thickness direction, penetrating the thickness direction of the Incoloy 800 nickel-based alloy strip and the 316L stainless steel strip to form a laser molten pool. After solidification, the Incoloy 800 nickel-based alloy strip and the 316L stainless steel strip are metallurgically bonded. After the printing process is completed, a thin-walled double-layer heterogeneous metal finished part with a thickness of 1.7mm and a height of 150mm is obtained.

[0060] The feeding speed of the Incoloy 800 nickel-based alloy strip and the moving speed of the 316L stainless steel strip are the same as those of the laser beam, both being 170 cm / min. Argon gas is used for both front and back protection during the printing process, with a laser front protection gas flow rate of 15 L / min and a back protection gas flow rate of 15 L / min. The laser beam is generated by a fiber laser, with a beam spot size of 0.2 mm, an energy of 3000 W, and a defocusing amount of -1 mm.

[0061] Figure 2The diagram shows the macroscopic structure of the thin-walled bilayer heterogeneous metal prepared in Example 1 at point A. As can be seen from the diagram, the cross-section forms a sandwich structure of "metal A - intermediate gradient layer - metal B", and the junction of the two metals forms a mechanical interlocking cross-section, an intermediate gradient coupling layer, and a metallurgical bonding region with mechanical interlocking and metallurgical bonding effects.

[0062] Figure 3 To enable laser-penetrated strip printing of thin-walled, double-layered heterogeneous metal double-vortex molten pools and their post-solidification morphology, from Figure 3 (a) and Figure 3 As can be seen from (b), the temperature field and flow behavior of the double-vortex molten pool indicate that the center of the molten pool exhibits a dispersive rapid solidification mode. Figure 3 (c) and Figure 3 As can be seen in (d), the laser beam penetrates the heterogeneous layered metal during welding. The liquid metal in the laser molten pool is subjected to the surface tension caused by the longitudinal and transverse temperature gradients and the frictional force of the steam jet in the keyhole, which together generate relatively independent eddies. This makes the molten metal in the upper and lower parts and the left and right parts of the laser molten pool relatively independent, forming a double eddy current molten pool. Under the condition of a large temperature and concentration gradient, the molten pool solidifies rapidly, so that the composition and structure of the weld remain relatively independent in both the longitudinal and transverse directions, achieving mechanical interlocking and metallurgical bonding.

[0063] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for 3D printing thin-walled double-layer heterogeneous metal using laser-penetrated strip, characterized in that, Includes the following steps: S1: Perform part modeling and 3D model data processing. Use software to slice and layer the designed geometric model of thin-walled double-layer heterogeneous metal finished parts to generate corresponding printing data; confirm the placement and orientation of the parts, set printing parameters, and generate the printing program based on the printing data using slicing software. S2: Metal strips A and B are fed into the laser heat source of the 3D printing equipment through the strip feeding system and fed into the laser heat source along the set path, where they are tightly bonded. At the same time, the laser beam at the laser heat source moves along the set path and penetrates the thickness direction of metal strips A and B to form a molten pool. After solidification, mechanical interlocking and metallurgical bonding of metal strips A and B are achieved. After the printing process is completed, a thin-walled double-layer heterogeneous metal finished part is obtained. The feeding speed of the A metal strip and the B metal strip is the same as the moving speed of the laser beam; there is an angle between the laser beam and the normal of the A metal strip and the B metal strip along the thickness direction; The angle between the laser beam and the normals of metal strips A and B along the thickness direction is 35°~90°; the feeding speed of metal strips A and B and the moving speed of the laser beam are both 10~1000cm / min. The laser beam has a beam spot size of 0.01~5mm, an energy of 100~8000W, and a defocusing amount of -2~5mm; The molten pool is a double vortex molten pool; The materials of metal strip A and metal strip B are different kinds of miscible metals; The cross-sectional morphology of the thin-walled double-layer heterogeneous metal is a sandwich structure of "metal A - intermediate gradient layer - metal B".

2. The method for laser-penetrating strip 3D printing of thin-walled double-layer heterogeneous metal according to claim 1, characterized in that, The geometric model of the thin-walled double-layer heterogeneous metal part is constructed using software, and the path of the laser beam and the strip feeding system in the 3D printing equipment is planned according to the geometric model; the laser beam is generated by a fiber laser.

3. The method for laser-penetrating strip 3D printing of thin-walled double-layer heterogeneous metal according to claim 1, characterized in that, In step S2, positive protection and back protection are achieved in an argon atmosphere. The flow rate of the positive protection argon gas is 8~45L / min, and the flow rate of the back protection argon gas is 8~45L / min.

4. The method for laser-penetrating strip 3D printing of thin-walled double-layer heterogeneous metal according to claim 1, characterized in that, The material of metal strip A is a nickel-based alloy, titanium alloy, aluminum alloy, or magnesium alloy metal-based composite material; the material of metal strip B is a nickel-based alloy, titanium alloy, aluminum alloy, or magnesium alloy metal-based composite material; the thickness of metal strip A and metal strip B is 0.1~10mm and the width is 1~25mm.

5. The method for 3D printing thin-walled double-layer heterogeneous metal using laser-penetrating strips according to claim 4, wherein the material of the A metal strip is steel, copper, or aluminum; and the material of the B metal strip is steel, copper, or aluminum.

6. The method for laser-penetrating strip 3D printing of thin-walled double-layer heterogeneous metal according to claim 1, characterized in that, The strip feeding system enables multi-degree-of-freedom constraints on metal strips A and B.

7. A thin-walled, double-layered heterogeneous metal, characterized in that, The material was prepared using a laser-penetrating strip 3D printing method according to any one of claims 1 to 6 for preparing thin-walled double-layer heterogeneous metal.

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