Method for regulating and controlling aluminum-steel bimetallic interface morphology based on box dam type structure
By using a dam-type intermediate layer structure and nickel-based alloys, the morphology of the aluminum-steel heterobimetallic interface was controlled, solving the problem of brittle intermetallic compound formation and improving the interface strength and overall mechanical properties.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-15
- Publication Date
- 2026-04-14
AI Technical Summary
In aluminum-steel heterogeneous bimetallic structures, brittle and hard intermetallic compounds are easily formed at the joint interface, which severely reduces their mechanical properties and hinders their industrial application.
A dam-type interlayer structure is adopted, which uses a nickel-based alloy interlayer to suppress the formation of brittle Fe-Al intermetallic compounds. The interface microstructure is controlled by laser cladding and electric arc additive manufacturing technology, and the interface strength is improved by combining micro-mechanical interlocking.
It effectively reduces the thickness of intermetallic compounds at the interface, inhibits crack propagation, and enhances the bonding strength and reliability of aluminum-steel heterostructures, achieving high-strength and high-efficiency preparation.
Smart Images
Figure CN121847898A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of arc additive manufacturing of metallic materials. Specifically, it relates to a method for regulating intermetallic compounds at the interface of aluminum-steel heterogeneous bimetallic structures using a dam-type intermediate layer structure. Background Technology
[0002] The selection of lightweight materials, the design of lightweight structures, and the optimization of lightweight manufacturing processes are core technological means to achieve industrial lightweighting transformation. These methods can effectively reduce product energy consumption and pollutant emissions, and are of great significance to promoting the green and sustainable development of industry. Aluminum-steel heterogeneous bimetallic structures combine the low density, high specific strength, and good corrosion resistance of aluminum alloys with the low cost, high strength, and processing performance of steel, making them promising for application in the field of automotive lightweight manufacturing.
[0003] However, due to the significant differences in the physical and chemical properties of aluminum and steel, it is easy for defects to form at the interface of aluminum-steel heterogeneous bimetallic structures. , , Various intermetallic compounds (IMCs) are present, which have extremely high hardness and extremely poor toughness. They are typical brittle and hard phases, which seriously reduce the mechanical properties of aluminum-steel heterostructures and greatly hinder the industrial application and development of aluminum-steel heterostructures.
[0004] Therefore, for aluminum-steel heterobimetallic structures, suppressing the formation of brittle Fe-Al intermetallic compounds and modifying their compound structures to achieve high-strength interfacial bonding have become current research priorities. Summary of the Invention
[0005] The purpose of this invention is to provide a method for controlling the morphology of the aluminum-steel bimetallic interface based on a dam-like structure. By leveraging the inhibitory effect of a nickel-based alloy interlayer on the formation of brittle Fe-Al intermetallic compounds, the microstructure of the interfacial metal compounds can be precisely controlled through the dam-like interlayer structure. This effectively hinders crack propagation and exerts a micro-mechanical interlocking effect, further improving the interfacial strength of the aluminum-steel heterostructure, with the aim of achieving high-strength, high-efficiency, and high-reliability fabrication of aluminum-steel heterostructures.
[0006] The objective of this invention is achieved through the following technical solution: a method for controlling the morphology of an aluminum-steel bimetallic interface based on a dam-type structure, characterized by the following steps: S1. Preparing a dam-type intermediate layer structure on the steel surface using laser cladding; S2. Applying an appropriate amount of flux to the steel surface and performing additive manufacturing in a protective gas environment to obtain an aluminum-steel heterogeneous bimetallic structure.
[0007] Preferably, the surface of the steel plate has been cleaned by sandpaper or grinding wheel to remove the surface oxide film and other contaminants.
[0008] Preferably, the dam-type intermediate layer structure is prepared by laser cladding using Inconel 625 nickel-based alloy powder.
[0009] Preferably, the flux is Noclock and the protective gas is 99.99% Ar.
[0010] Preferably, the aluminum material is AlSi5 wire, and the steel material is 316 steel plate (thickness is 5 mm).
[0011] Preferably, the arc additive manufacturing method employs cold metal transfer (CMT) technology.
[0012] Preferably, the additive manufacturing process parameters include: travel speed: 4~7 mm / s, wire feeding speed: 3~5 m / min, and protective gas flow rate: 10~20 L / min.
[0013] Further, the laser cladding process parameters in step S1 include: laser power: 250~300 W, scanning speed: 500~1000 mm / s, and energy density: 50~120 J / mm². 3 .
[0014] Further, the chemical composition of the 316 stainless steel described in step S1, in mass percentage (wt.%), is as follows: C: ≤0.03%, Si: ≤0.50%, Mn: ≤1.50%, P: ≤0.025%, S: ≤0.010%, Cr: 16.5%~17.8%, Ni: 10.2%~11.5%, Mo: 2.00%~2.30%, N: ≤0.08%, with the balance being Fe and unavoidable impurities.
[0015] Further, the composition of the AlSi5 filament described in step S1, by mass percentage, is as follows: Si: 4.5%~5.5%, Fe: ≤ 0.25%, Cu: ≤ 0.05%, Mn: ≤ 0.05%, Mg: ≤ 0.05%, Zn: ≤ 0.05%, Ti: ≤ 0.05%, other individual impurity elements: ≤ 0.05%, total of other impurity elements: ≤ 0.15%, with the balance being Al and unavoidable impurities.
[0016] The advantages of this invention are as follows: This invention combines a low-heat-input CMT process to reduce the thickness of intermetallic compounds (IMCs) at the aluminum-steel heterogeneous bimetallic structure interface; simultaneously, by utilizing the inhibitory effect of a nickel-based alloy interlayer on the formation of brittle Fe-Al intermetallic compounds, a dam-like interlayer structure is constructed to achieve precise control over the microstructure of intermetallic compounds generated by the interface reaction, thereby inhibiting crack initiation and propagation, and forming a synergistic effect with the microscale mechanical meshing effect; it aims to solve the key problem of brittle failure and fracture at the interface of aluminum-steel heterogeneous bimetallic structures, ultimately achieving high-strength, high-efficiency, and high-reliability integrated fabrication of aluminum-steel heterogeneous bimetallic structures. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the nickel-based alloy interlayer structure prepared by laser cladding process according to the present invention; wherein, (a) is a dam-type nickel-based alloy interlayer structure, (b) is a dot-type nickel-based alloy interlayer structure, and (c) is a planar nickel-based alloy interlayer structure.
[0018] Figure 2 This is a schematic diagram of the cross-sectional morphology of the aluminum-steel heterogeneous bimetallic structure prepared by arc additive manufacturing according to the present invention; wherein, (a) is a dam-type structure with a dam thickness of 30 µm, (b) is a dam-type structure with a dam thickness of 50 µm, (c) is a point-like structure with a characteristic size of 30 µm, (d) is a point-like structure with a characteristic size of 50 µm, (e) is a planar structure with a characteristic size of 50 µm, and (f) is the cross-sectional morphology of the aluminum-steel heterogeneous bimetallic structure without cladding intermediate layer;
[0019] Figure 3 These are microscopic images of the interface of the aluminum-steel heterogeneous bimetallic structure produced by arc additive manufacturing in this invention; wherein, (a) is the microscopic morphology of the aluminum / steel interface with a dam thickness of 30 µm, (b) is the microscopic morphology of the aluminum / steel interface with a dam thickness of 50 µm, (c) is the microscopic morphology of the point-like aluminum / steel interface with a characteristic size of 30 µm, (d) is the microscopic morphology of the point-like aluminum / steel interface with a characteristic size of 50 µm, (e) is the microscopic morphology of the planar aluminum / steel interface with a characteristic size of 50 µm, and (f) is the microscopic morphology of the aluminum / steel interface without cladding intermediate layer.
[0020] Figure 4 This is a shear stress diagram of the arc additive aluminum-steel heterogeneous bimetallic structure of the present invention; Detailed Implementation
[0021] The following detailed description, in conjunction with specific embodiments, illustrates the method for preparing aluminum-steel heterogeneous bimetallic intermetallic compounds based on a dam-type intermediate layer structure controlled by arc additive manufacturing, provided by this invention. It should be understood that the embodiments described herein are only some preferred embodiments of the invention, and not all embodiments; all other corresponding embodiments obtained by those skilled in the art based on the disclosed technical solutions of this invention without creative effort are within the protection scope of this invention. However, they should not be construed as limiting the scope of protection of this invention.
[0022] Example 1
[0023] This embodiment provides a method for controlling the morphology of the aluminum-steel bimetallic interface based on a dam-like structure, comprising the following steps:
[0024] The surface of 316 stainless steel is cleaned with sandpaper or a grinding wheel and then rinsed with anhydrous ethanol, and the substrate is then dried.
[0025] A dam-type intermediate layer structure with a dam thickness of 30 µm was prepared by laser cladding of nickel-based alloy powder onto the surface of 316 stainless steel. Figure 1 (a).
[0026] A special fixture was used to position and clamp the 316 stainless steel substrate with a diamond-shaped dam-like intermediate layer structure. Then, an appropriate amount of uniform Noclock flux was applied to the surface of the intermediate layer structure of the substrate. AlSi5 aluminum alloy wire was selected as the additive material, and the aluminum-steel heterogeneous bimetallic structure was prepared by CMT (cold metal transfer) arc additive manufacturing technology (wherein, the CMT process mode was CMT+P+ADV).
[0027] In the additive manufacturing process of the aluminum-steel heterogeneous bimetallic structure in Example 1, no typical defects such as spatter, cracks, and dents, which are common in this type of process, were generated, and the forming stability was excellent. Figure 2 (a) shows the cross-sectional morphology of the structure. As can be seen from the figure, there are only a few tiny pores in the upper layer of the additive manufacturing area, and the defect density is extremely low. Figure 3 (a) shows the microstructure of its interface. A continuous and uniform intermetallic compound layer is formed at the interface. The average thickness is 8 μm, and there are no interface failure defects such as cracks or peeling. The bonding state is good.
[0028] The compressive-shear strength of this aluminum-steel heterogeneous bimetallic structure was tested using a universal tensile testing machine. The test results are as follows: Figure 4 As shown in a, the maximum shear strength of this structure can reach 77±2.8 MPa.
[0029] Example 2
[0030] The only difference between this embodiment and Embodiment 1 is the adjustment of the dam thickness parameter, which is set to 50 μm.
[0031] In the aluminum-steel heterogeneous bimetallic structure prepared in Example 2, the overall pore density is low, but a small number of larger pores appear in the top region on the aluminum side, and their cross-sectional morphology is as follows. Figure 2 As shown in (b), no failure defects such as cracks or peeling were generated in the interface area, and the intermetallic compound layer formed at the interface was extremely thin. Its average thickness was only about 5 μm after characterization. The microstructure of the interface is shown in Figure 3(b).
[0032] Compression-shear strength tests were conducted on the aluminum-steel heterogeneous bimetallic structure of this embodiment. The results showed that its maximum shear strength reached 84±2.0 MPa. Specific test data are as follows: Figure 4 As shown in b in the figure, it can be seen that when the thickness of the dam is adjusted to 50 μm, an optimized intermetallic compound layer thickness and excellent mechanical properties can be obtained.
[0033] Comparative Example 1
[0034] The only difference from Example 1 is that a dotted intermediate layer structure is designed on the steel surface, with a characteristic dimension of 30 µm, such as... Figure 1 (c).
[0035] In the aluminum-steel heterobimetallic structure prepared in this comparative example, the number of pores is extremely small, with only a small number of larger pores distributed in the top region of the aluminum side. Its cross-sectional microstructure is as follows: Figure 2 As shown in (c), the thickness of the intermetallic compound layer formed at the interface is significantly increased, and obvious layering characteristics are observed. Two different intermetallic compound layers of different phases can be observed. The average thickness is approximately 10 μm. No structural defects such as cracks are found in the interface region. For the specific interface micromorphology, see [image missing]. Figure 3 (c).
[0036] Characterized by compression-shear strength testing, the shear strength of this aluminum-steel heterogeneous bimetallic structure is 74 ± 1.4 MPa, and the corresponding test data curve is shown below. Figure 4 As shown in c in the figure.
[0037] Comparative Example 2
[0038] The only difference from Example 2 is that a dotted intermediate layer structure with a feature size of 50 µm is designed on the steel surface.
[0039] This aluminum-steel heterogeneous bimetallic structure has very few porosity defects; only a few larger pores exist on the top of the aluminum side. Figure 2(d) A relatively thick intermetallic compound layer forms at the interface, with an average thickness of approximately 12 µm. This compound layer exhibits distinct layering characteristics, containing two different intermetallic compounds. Furthermore, longitudinal cracks were observed in the intermetallic compound layer at the interface, see [reference needed]. Figure 3 (d).
[0040] The shear strength is only 64±4.2 MPa, see Figure 4 d in.
[0041] Comparative Example 3
[0042] Compared to Example 2, the main difference in this example is that a planar intermediate layer structure with a feature size of 50 µm is provided on the steel surface, such as... Figure 1 As shown in (e).
[0043] The aluminum-steel heterobimetallic structure has very few porosity defects, but its wettability is significantly lower than that of Example 2, such as... Figure 2 As shown in (e), a large, bulky intermetallic compound forms at the interface, with an average thickness of approximately 9 µm. This compound layer exhibits significant delamination, and some intermetallic compound layers detach. No cracks were observed in the intermetallic compound. Figure 3 (e).
[0044] Its shear strength was tested to be 73 ± 2.3 MPa. Figure 4 The 'e' in the middle.
[0045] Comparative Example 4 The only difference from Example 2 is that no intermediate layer structure is designed on the steel surface.
[0046] Numerous dense pores appear in aluminum-steel heterogeneous bimetallic structures, such as Figure 2 (f); the intermetallic compound at the interface is relatively thin, with an average thickness of about 7 µm, but continuous cracks appear at the intermetallic compound interface, see Figure 3 (f).
[0047] The shear strength is only 47±0.7 MPa, see Figure 4 f in the text.
[0048] Table 1. Compression-shear test results of aluminum-steel heterogeneous bimetallic structures in Examples 1-2 and Comparative Examples 1-4
[0049] The test results (as shown in Table 1) show that the average thickness of the intermetallic compound at the interface of the aluminum-steel heterogeneous bimetallic structures with dam-type interlayers prepared on the steel surface by laser cladding in Examples 1-2 is significantly lower than that of the aluminum-steel heterogeneous bimetallic structures in Comparative Examples 1-4 (without dam-type interlayers). At the same time, the shear strength of this type of heterogeneous bimetallic structure with dam-type interlayers is significantly higher than that of the control group structure without dam-type interlayers.
[0050] In summary, the introduction of a dam-type nickel-based alloy interlayer effectively suppresses the formation of brittle intermetallic compounds, enabling precise control over the microstructure of these compounds at the interface. This interlayer simultaneously hinders crack propagation and provides micro-mechanical interlocking, significantly enhancing the bonding strength of the aluminum / steel interface. During additive manufacturing, the forming process is stable, and the resulting structure exhibits no obvious cracks, porosity, or other defects. Therefore, the use of a dam-type nickel-based alloy interlayer not only promotes the metallurgical bonding of aluminum-steel heterostructures but also significantly improves their overall mechanical properties.
[0051] The above description is merely an exemplary preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several further improvements, optimizations and equivalent substitutions can be made without departing from the core principles and inventive concept of the present invention, and all such adjustments should be included within the scope of protection defined by the appended claims of the present invention.
Claims
1. A method for controlling the morphology of an aluminum-steel bimetallic interface based on a dam-like structure, characterized in that, Includes the following steps: S1. Prepare a dam-like intermediate layer structure on the surface of steel; S2. Apply an appropriate amount of flux to the surface of the steel and perform additive manufacturing in a protective gas environment to obtain an aluminum-steel heterogeneous bimetallic structure.
2. The method according to claim 1, characterized in that, The surface of the steel was cleaned by sanding or grinding with sandpaper or grinding wheel.
3. The method according to claim 1, characterized in that, The dam-type intermediate layer structure is prepared by laser cladding, and the powder used is Inconel 625 nickel-based alloy powder.
4. The method according to claim 3, characterized in that, The laser cladding process parameters are as follows: laser power: 250~300 W, scanning speed: 500~1000 mm / s, energy density: 50~120 J / mm². 3 .
5. The method according to claim 1, characterized in that, The flux is Noclock, and the protective gas is 99.99% Ar.
6. The method according to claim 1, characterized in that, The aluminum material is made of AlSi5 wire, and the base steel is made of 316 steel plate.
7. The method according to claim 1, characterized in that, The electric arc additive manufacturing method employs cold metal transfer (CMT) technology, with the mode selected as CMT+P+ADV.
8. The method according to any one of claims 1 to 6, characterized in that, The additive manufacturing process parameters include: travel speed: 4~7 mm / s, wire feeding speed: 3~5 m / min, and protective gas flow rate: 10~20 L / min.
9. The application of the method for preparing aluminum-steel heterogeneous bimetallic intermetallic compound based on the controlled arc additive manufacturing of a dam-type intermediate layer structure as described in any one of claims 1 to 7 in the preparation of components in the aerospace and automotive fields.