Additive manufacturing method of aluminum / iron multi-material component

Abstract

The invention relates to an additive manufacturing method of an aluminum / iron multi-material component, which is characterized in that additive manufacturing is carried out through a laser directional energy deposition method, and a CuZr alloy is introduced between an aluminum raw material layer and an iron raw material layer as a middle layer. According to the invention, the CuZr intermediate layer is introduced between the aluminum and the iron to improve the defects caused by large thermal physical metallurgical properties such as thermal expansion coefficient, melting point, thermal conductivity and the like between the aluminum and the iron, so that the interface stability is improved. The CuZr intermediate layer is introduced between aluminum and iron, so that direct contact and reaction of aluminum atoms and iron atoms are effectively prevented, formation of Fe-Al hard and brittle intermetallic compounds is inhibited, and the problem of interface cracking of aluminum / iron multi-material components is solved. A CuZr intermediate layer is introduced between aluminum and iron to realize bidirectional metallurgy of an aluminum / iron material, and an aluminum / iron multi-material component with good interface bonding and mechanical properties can be prepared.

Description

Technical Field

[0001] The present invention relates to the field of additive manufacturing, and more particularly to an additive manufacturing method for an aluminum / iron multi-material component. Background Art

[0002] Additive manufacturing technology does not require traditional tools, jigs, and multiple processing steps. Complex-shaped parts can be rapidly manufactured by layer-by-layer deposition on a single device, solving the problem of integrated forming of many complex-structured parts. Laser-directed energy deposition (LDED) is an advanced additive manufacturing technology formed based on laser cladding technology, which uses a laser as a heat source and pre-placed or synchronous powder (wire) feeding as the forming material, and can fabricate metal parts that are not restricted by materials, have high density, and excellent mechanical properties.

[0003] Compared with components made of a single material, multi-material components can meet specific performance requirements such as lightweight, high strength and toughness, high thermal conductivity, and corrosion resistance in local areas by distributing materials as needed, and achieve the integration of multiple properties and functions. The aluminum / iron bimetallic structure combines the lightweight of aluminum and the high strength of iron, and lightweight application goals of "replacing steel with aluminum" have been proposed in fields such as ships, automobiles, and aerospace. At present, aluminum / iron multi-material components are usually obtained by connection processes such as riveting, diffusion bonding, and welding. The interface bonding of the riveting process is poor, and it is prone to loosening and deformation during long-term service. Diffusion, welding and other connection processes are all combined on a specific surface, which limits the geometric design of the interface and the flexible layout of heterogeneous materials. For example, in diffusion welding and explosion welding, the bonding surface is usually a near-plane to balance the contact pressure; in friction stir welding, laser or electron beam welding, the stirring pin / high-energy beam directly contacts the materials to be welded, and it is difficult to realize the connection of heterogeneous alloys with complex internal multi-level structures. The processing method of LDED technology for flexible deposition of materials point-by-point, line-by-line, and region-by-region is an effective technical means to realize the integral forming of aluminum / iron multi-material components.

[0004] Currently, the interface bonding methods for dissimilar alloys used in laser additive manufacturing mainly include direct bonding method, gradient transition method, and intermediate layer method. The direct bonding method is used for materials with similar metallurgical properties, which can stably diffuse to form a strong interface in the molten state. However, for heterogeneous alloys with low compatibility such as aluminum / iron, direct bonding is likely to cause interface defects. The gradient transition method can slow down the sudden change of composition and stress by introducing a material gradient in the interface region, but it has limited effect on heterogeneous materials with too large performance differences such as aluminum / iron.

[0005] Aluminum / iron multi-material components face interface bonding problems during laser additive manufacturing. On the one hand, there are significant differences in thermophysical metallurgical properties such as thermal expansion coefficient, melting point, and thermal conductivity between aluminum and iron. High stresses are generated during solidification, which can easily lead to defects such as cracks. On the other hand, the fusion of aluminum / iron powders under the action of high-energy lasers easily forms a large number of brittle intermetallic compounds such as FeAl 2 、FeAl 3 、Fe 2 Al 5 etc., resulting in interface brittleness and cracking. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an additive manufacturing method for aluminum / iron multi-material components, which can improve the compatibility between aluminum and iron, inhibit the quantity and speed of the generation of interface compounds, and improve interface stability.

[0007] The technical solution adopted by the present invention to solve its technical problems is: to construct an additive manufacturing method for aluminum / iron multi-material components, and perform additive manufacturing by the method of laser directed energy deposition, and introduce a CuZr alloy as an intermediate layer between the aluminum raw material layer and the iron raw material layer.

[0008] According to the above solution, the method of performing additive manufacturing by the method of laser directed energy deposition includes the following steps:

[0009] S1. Use three-dimensional drawing software to design a multi-material component model, add a CuZr alloy layer at the aluminum / iron interface, generate an STL file, use slicing software to slice the model, import the processed file into a laser directed energy deposition forming device, and set the printing areas and printing parameters of the three materials of aluminum, CuZr alloy, and iron;

[0010] S2. Add aluminum, CuZr, and iron powders respectively into different powder feeding channels of the coaxial nozzle of the powder feeding system of the laser directed energy deposition forming device, preheat the substrate, and print the aluminum / iron multi-material component layer by layer;

[0011] S3. Print the first material, aluminum or iron, for each layer;

[0012] S4. After the first material is printed, change and call the powder feeding channel to print the CuZr intermediate layer;

[0013] S5. After the CuZr intermediate layer is printed, change the powder feeding channel again and print the second material, iron or aluminum, until the printing of this layer is completed;

[0014] S6. Repeat steps S3 - S5 layer by layer until the aluminum / iron multi-material component is completely completed;

[0015] S7. Cut and separate the printed part from the substrate to obtain an aluminum / iron multi-material component product.

[0016] According to the above solution, in the step S1, the thickness of the laser directed energy deposition forming of the CuZr intermediate layer is 0.1 - 5 mm.

[0017] According to the above solution, in the step S1, when printing aluminum, the process parameters are set as follows: laser power 1000 - 2000 W, scanning speed 500 - 1500 mm / min, scanning spacing 0.5 - 1.5 mm, single-layer lifting height 0.3 - 0.7 mm, spot size 1.5 - 8 mm, powder feeding rate 0.5 - 1.5 r / min, gas flow rate 2 - 8 L / min.

[0018] According to the above solution, in the step S1, when printing iron, the process parameters are set as follows: laser power 1000 - 3000 W, scanning speed 200 - 1500 mm / min, scanning spacing 0.5 - 1.5 mm, single-layer lifting height 0.3 - 0.7 mm, spot size 1.5 - 8 mm, powder feeding rate 0.5 - 1.5 r / min, gas flow rate 2 - 8 L / min.

[0019] According to the above solution, in the step S1, when printing CuZr, the process parameters are set as follows: laser power 1000 - 2000 W, scanning speed 100 - 1500 mm / min, scanning spacing 0.5 - 1.5 mm, single-layer lifting height 0.3 - 0.7 mm, spot size 1.5 - 8 mm, powder feeding rate 0.5 - 1.5 r / min, gas flow rate 2 - 8 L / min.

[0020] According to the above solution, in steps S3 - S5, the particle size range of the aluminum, CuZr, and iron powders used is 30 - 150 μm.

[0021] According to the above solution, when printing aluminum, CuZr, and iron materials in steps S3 - S5, a protective gas is used as the powder-carrying gas.

[0022] According to the above solution, when printing aluminum, CuZr, and iron materials in steps S3 - S5, the substrate material is the same as that for printing the first layer of the multi-material, or a CuZr substrate is used, and the preheating temperature of the substrate is 0 - 500 °C.

[0023] According to the above solution, when printing aluminum, CuZr, and iron materials in steps S3 - S5, a CuZr alloy barrier is ensured between aluminum and iron.

[0024] The mechanism of the present invention is as follows:

[0025] The present invention improves the compatibility, suppresses the quantity and speed of the formation of interfacial compounds, and enhances the interfacial stability by introducing a CuZr interlayer between aluminum and iron. The brittle Fe-Al compound is the key factor affecting the interfacial performance. By introducing the CuZr alloy interlayer, the direct contact between aluminum and iron can be avoided. In the CuZr-Fe system, no Fe-Cu compound is formed at high temperatures, mainly involving transformations and the diffusion and miscibility of ε-Cu and Fe; in the CuZr-Al system, under the condition of laser melting and strong undercooling, compounds with lower Gibbs free energy such as θ-Al 2 Cu, Al 3 Zr, etc., with relatively good toughness will be formed, inhibiting the formation of harmful Al-Fe phases, thereby realizing the "two-way" metallurgy of aluminum / iron materials and solving the problem of additive manufacturing of aluminum / iron connections.

[0026] Implementing the additive manufacturing method of the aluminum / iron multi-material component of the present invention has the following beneficial effects:

[0027] 1. Introducing a CuZr interlayer between aluminum and iron to improve the defects caused by the large differences in thermophysical metallurgical properties such as the coefficient of thermal expansion, melting point, and thermal conductivity between aluminum and iron, and enhancing the interfacial stability. Introducing a CuZr interlayer between aluminum and iron effectively prevents the direct contact and reaction of aluminum and iron atoms, inhibits the formation of hard and brittle Fe-Al intermetallic compounds, thereby solving the problem of interfacial cracking of aluminum / iron multi-material components. Introducing a CuZr interlayer between aluminum and iron realizes the "two-way" metallurgy of aluminum / iron materials, and successfully prepares aluminum / iron multi-material components with good interfacial bonding and mechanical properties.

[0028] 2. During the laser additive manufacturing of aluminum / iron multi-materials, if aluminum and iron are directly combined, complex hard and brittle Al-Fe compounds will be introduced during the laser fusion process, resulting in severe interfacial cracking. The present invention proposes to introduce a CuZr interlayer to avoid the direct contact between aluminum and iron, which can simultaneously form immiscible diffusion zones or relatively ductile new metallurgical phases with aluminum and iron between aluminum and iron, realizing the "two-way" metallurgy of aluminum / iron heterogeneous alloys and improving the interfacial bonding performance of aluminum / iron.

[0029] 3. Traditional LDED uses the same nozzle to deliver the same material, and can only achieve the switching of materials in the printing direction, and cannot achieve the material change in the X and Y axis directions within one layer. The present invention uses a multi-channel powder feeder to in-situ feed materials with different compositions by different nozzles, and prepares multi-material components with different microzone compositions. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0031] Figure 1 is a schematic diagram of the principle of the additive manufacturing method of the aluminum / iron multi-material component of the present invention;

[0032] Figure 2 It is a flow chart of the additive manufacturing method for the aluminum / iron multi-material component of the present invention. Specific embodiments

[0033] For a clearer understanding of the technical features, objectives, and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0034] Example 1

[0035] This is an example of using the present invention to in-situ form AlSi12 / pure iron multi-materials by laser additive manufacturing.

[0036] The specific steps are as follows:

[0037] S1. Use CAD software to design a multi-material component model and generate an STL file. Use Magics slicing software to slice the model, and import the processed file into a laser directed energy deposition forming device. Set the forming ranges and process parameters of three materials, namely AlSi12 alloy, CuZr, and pure iron. The thickness of the CuZr alloy layer is 0.1 mm;

[0038] S2. Add AlSi12 powder, CuZr powder, and pure iron powder with a particle size range of 50 - 100 μm into different powder feeding channels of the coaxial nozzle in the powder feeding system of the laser directed energy deposition forming device, and introduce argon with a volume ratio of 99% and an oxygen content not greater than 900 ppm into the powder feeding channels as a protective gas. Preheat the CuZr substrate to 250 °C and print layer by layer according to the model slice data;

[0039] S3. Set the process parameters of the laser directed energy deposition forming device as follows: laser power 1600 W, scanning speed 900 mm / min, scanning spacing 1.1 mm, single-layer lifting height 0.5 mm, spot size 2 mm, powder feeding rate 0.8 r / min, gas flow rate 5 L / min. The powder feeding system evenly sprays AlSi12 powder to print the AlSi12 part of the first layer on the CuZr substrate;

[0040] S4. Adjust the process parameters of the laser directed energy deposition forming device to: laser power 1400 W, scanning speed 500 mm / min, scanning spacing 0.9 mm, single-layer lifting height 0.5 mm, spot size 2 mm, powder feeding rate 0.8 r / min, gas flow rate 5 L / min. Replace the powder feeding channel and evenly spray CuZr powder to print the CuZr part of the first layer;

[0041] S5. Adjust the process parameters of the laser directed energy deposition forming equipment as follows: laser power 1800 W, scanning speed 700 mm / min, scanning spacing 1.0 mm, single-layer lifting height 0.5 mm, spot size 2 mm, powder feeding rate 0.8 r / min, gas flow rate 5 L / min. Replace the powder feeding channel and evenly spray pure Fe powder to print the pure Fe part of the first layer.

[0042] S6. Repeat steps S3 - S5 layer by layer until the AlSi12 / pure iron multi-material component is completely finished.

[0043] S7. After printing, cool to room temperature and use wire cutting to remove the part to obtain the AlSi12 / pure iron multi-material component product.

[0044] Example 2

[0045] This is an example of in-situ forming of AlMgScZr / 316L stainless steel multi-materials by laser additive manufacturing using the present invention. The specific steps are as follows:

[0046] S1. Use Solidworks software to design the multi-material component model and generate an STL file. Use Cura slicing software to slice the model, and import the processed file into the laser directed energy deposition forming equipment. Set the forming ranges and process parameters of three materials, namely AlMgScZr, CuZr, and 316L. The thickness of the CuZr alloy layer is 5 mm.

[0047] S2. The laser directed energy deposition forming equipment uses a carrier gas type powder feeder. Add AlMgScZr powder, CuZr powder, and 316L powder with a particle size range of 50 - 100 μm into different powder feeding channels of the coaxial nozzle in the powder feeding system respectively, and introduce argon with a volume ratio of 99% and an oxygen content not greater than 900 ppm into the powder feeding channel as the protective gas. Preheat the CuZr substrate to 150 °C and print layer by layer according to the model slicing data.

[0048] S3. Set the process parameters of the laser directed energy deposition forming equipment as follows: laser power 2400 W, scanning speed 1000 mm / min, scanning spacing 1.2 mm, single-layer lifting height 0.4 mm, spot size 1.6 mm, powder feeding rate 0.6 r / min, gas flow rate 4 L / min. The powder feeding system evenly sprays 316L powder to print the 316L part of the first layer on the CuZr substrate.

[0049] S4. Adjust the process parameters of the laser directed energy deposition forming equipment as follows: laser power 1600 W, scanning speed 800 mm / min, scanning spacing 1.2 mm, single-layer lifting height 0.4 mm, spot size 1.6 mm, powder feeding rate 0.6 r / min, gas flow rate 4 L / min. Replace the powder feeding channel, evenly spray out CuZr powder, and print the CuZr part of the first layer.

[0050] S5. Adjust the process parameters of the laser directed energy deposition forming equipment as follows: laser power 1800 W, scanning speed 1200 mm / min, scanning spacing 1.4 mm, single-layer lifting height 0.4 mm, spot size 1.6 mm, powder feeding rate 0.6 r / min, gas flow rate 4 L / min. Replace the powder feeding channel, evenly spray out AlSi10Mg powder, and print the AlSi10Mg part of the first layer.

[0051] S6. Repeat steps S3 - S5 layer by layer until the AlMgScZr / 316L stainless steel multi-material component is completely finished.

[0052] S7. After printing, cool to room temperature, and cut the part with wire cutting to obtain the aluminum / iron multi-material component product.

[0053] In the present invention, the direct bonding method and the gradient transition method are used as the interface bonding methods for additive manufacturing of aluminum / iron multi-material components. Inevitably, interface bonding problems are faced, which are mainly reflected in the material compatibility between aluminum alloy and iron and the interface chemical reaction. On the one hand, the thermal physical metallurgical properties such as the coefficient of thermal expansion, melting point, and thermal conductivity between aluminum and iron are quite different. The molten pool is unstable in the molten state, and high stress is generated during solidification, which is extremely likely to cause cracks. On the other hand, a large number of intermetallic compounds are generated by the reaction between aluminum and iron under the action of high-energy laser, resulting in interface brittleness and cracking.

[0054] In the present invention, a CuZr intermediate layer is introduced between aluminum and iron to improve compatibility, inhibit the quantity and speed of the generation of the interface compound Fe - Al, and improve interface stability.

[0055] Compared with the prior art, the advantages of the present invention are as follows:

[0056] 1. A CuZr intermediate layer is introduced between aluminum and iron to improve the defects caused by the large differences in thermal physical metallurgical properties such as the coefficient of thermal expansion, melting point, and thermal conductivity between aluminum and iron, and improve interface stability.

[0057] 2. Introducing a CuZr intermediate layer between aluminum and iron effectively prevents the direct contact and reaction of aluminum and iron atoms, inhibits the formation of hard and brittle Fe - Al intermetallic compounds, thus solving the interface cracking problem of aluminum / iron multi-material components.

[0058] 3. Introduce a CuZr interlayer between aluminum and iron to achieve "two-way" metallurgy of aluminum / iron materials, and successfully fabricate aluminum / iron multi-material components with good interfacial bonding and mechanical properties.

[0059] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the spirit of the present invention and the scope protected by the claims. All of these are within the protection scope of the present invention.

Claims

1. An additive manufacturing method for aluminum / iron multi-material components, characterized in that: Additive manufacturing is performed by laser directed energy deposition, and CuZr alloy is introduced as an intermediate layer between the aluminum raw material layer and the iron raw material layer.

2. The additive manufacturing method of aluminum / iron multi-material components according to claim 1, characterized in that: The method of additive manufacturing by laser directed energy deposition comprises the following steps: S1. Design a multi-material component model using 3D drawing software, add a CuZr alloy layer at the aluminum / iron interface, generate an STL file, slice the model using slicing software, import the processed file into the laser directed energy deposition molding equipment, and set the printing area and printing parameters of the three materials of aluminum, CuZr alloy, and iron; S2, adding aluminum, CuZr and iron powders into different powder feeding channels of the coaxial nozzle of the powder feeding system of the laser directed energy deposition molding equipment, preheating the substrate, and printing aluminum / iron multi-material components layer by layer; S3, each layer is printed with the first material, aluminum or iron; S4. After the first material is printed, the powder feeding channel is changed to print the CuZr middle layer; S5. When the CuZr middle layer is printed, the powder feeding channel is changed again to print the second material, iron or aluminum, until the printing of this layer is completed; S6, repeating steps S3-S5 layer by layer until the aluminum / iron multi-material components are all completed; S7. Cut and separate the printed parts from the substrate to obtain an aluminum / iron multi-material component product.

3. The additive manufacturing method of aluminum / iron multi-material components according to claim 2, characterized in that: In the step S1, the CuZr intermediate layer is formed by laser directed energy deposition with a thickness of 0.1-5 mm.

4. The additive manufacturing method of aluminum / iron multi-material components according to claim 2, characterized in that: In the step S1, the process parameters for printing aluminum are set as follows: laser power 1000-2000 W, scanning speed 500-1500 mm / min, scanning spacing 0.5-1.5 mm, single layer lifting height 0.3-0.7 mm, spot size 1.5-8 mm, powder feeding rate 0.5-1.5 r / min, and gas flow rate 2-8 L / min.

5. The additive manufacturing method of aluminum / iron multi-material components according to claim 2, characterized in that: In the step S1, the process parameters for printing iron are set as follows: laser power 1000-3000 W, scanning speed 200-1500 mm / min, scanning spacing 0.5-1.5 mm, single-layer lifting height 0.3-0.7 mm, spot size 1.5-8 mm, powder feeding rate 0.5-1.5 r / min, and gas flow rate 2-8 L / min.

6. The additive manufacturing method of aluminum / iron multi-material components according to claim 2, characterized in that: In the step S1, the process parameters for printing CuZr are set as follows: laser power 1000-2000 W, scanning speed 100-1500 mm / min, scanning spacing 0.5-1.5 mm, single layer lifting height 0.3-0.7 mm, spot size 1.5-8 mm, powder feeding rate 0.5-1.5 r / min, and gas flow rate 2-8 L / min.

7. The additive manufacturing method of aluminum / iron multi-material components according to claim 2, characterized in that: The particle size range of the aluminum, CuZr and iron powders used in steps S3-S5 is 30-150 μm.

8. The additive manufacturing method of aluminum / iron multi-material components according to claim 2, characterized in that: When printing aluminum, CuZr, and iron materials in steps S3-S5, it is necessary to carry out under a protective gas, and the protective method is to use the protective gas as a powder carrier gas.

9. The additive manufacturing method of aluminum / iron multi-material components according to claim 2, characterized in that: When printing aluminum, CuZr, and iron materials in steps S3-S5, the substrate material is the same as the first layer of printing a multi-material build, or a CuZr substrate is used, and the substrate preheating temperature is 0-500°C.

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