High-strength and high-conductivity aluminum alloy and preparation method thereof

Abstract

The invention provides an AlSi10Mg alloy with uniformly distributed SiC and a preparation method of the AlSi10Mg alloy. Heat-treated AlSi10Mg alloy powder serves as a basic raw material, the surface of the AlSi10Mg alloy powder is evenly coated with graphene through electrostatic adsorption, ball milling, co-deposition, chemical reduction and other methods, the selective laser melting additive manufacturing technology is combined for forming, and the method can be used for producing parts which are complex in structure and have high requirements for mechanical performance and electrical conductivity. And the AlSi10Mg alloy powder is subjected to heat treatment to form Si phase precipitates. Graphene forms a three-dimensional conductive network, serves as a heat-conducting and electric-conducting medium to be filled in an alloy interface, can also serve as a carbon source, reacts with a Si phase in alloy powder under the action of a laser heat source to form SiC in situ, and the SiC is evenly distributed in the AlSi alloy. According to the selective laser melting forming SiC reinforced aluminum alloy obtained on the basis of the method, alloy structure micro-nano and matrix reinforcement are achieved at the same time, and the mechanical and conductive performance of the alloy is optimized. The problem that the strength and the conductivity of a traditional aluminum alloy cannot be considered at the same time is effectively solved.

Description

Technical Field

[0001] This invention belongs to the field of metal matrix composites, specifically relating to a high-strength, high-conductivity aluminum alloy and its additive manufacturing method. Background Technology

[0002] With the nation's vigorous promotion of manufacturing transformation and upgrading, aluminum alloys, as a lightweight, high-strength, and highly corrosion-resistant metallic material, have wide applications in transportation and electronics. However, conventional casting processes suffer from numerous problems such as low production efficiency, high costs, and environmental pollution. With the development of intelligent manufacturing, new manufacturing technologies such as additive manufacturing are increasingly attracting attention. Selective Laser Melting (SLM) is a novel method that uses high-energy lasers to melt metal powder, achieving 3D material forming.

[0003] However, additively manufactured aluminum alloys still face challenges such as insufficient strength. To address these issues, methods like adding rare earth elements and heat treatment are employed to enhance the strength of aluminum alloys. Adding hardening phases such as ceramics is one effective method to improve alloy strength. Currently, premixing methods such as ball milling are mainly used. However, achieving a uniform distribution of the strengthening phase is difficult, and the large size of SiC particles, being ceramic, hinders electron propagation, significantly reducing the alloy's conductivity.

[0004] Therefore, there is an urgent need to propose a new high-strength, high-conductivity aluminum alloy and its preparation method. Summary of the Invention

[0005] In view of this, the present invention aims to provide a high-strength, high-conductivity aluminum alloy and its preparation method. Through compositional and process design, a SiC-reinforced AlSi alloy is prepared, exhibiting high tensile strength and electrical conductivity to meet the application requirements of aluminum alloys in fields such as electronics and information technology.

[0006] This invention provides a high-strength, high-conductivity AlSi10Mg alloy, wherein the AlSi10Mg alloy contains two reinforcing phases: graphene and SiC.

[0007] Preferably, the graphene forms a three-dimensional network distributed on the interface of the aluminum alloy.

[0008] Preferably, the SiC is formed in situ and uniformly distributed in the alloy.

[0009] This invention provides a method for preparing the high-strength, high-conductivity aluminum alloy described above, comprising the following steps: AlSi alloy powder was subjected to solution treatment and aging treatment in sequence to obtain Al alloy with precipitated Si phase; Preferably, the AlSi alloy powder is an atomized spherical powder with a particle size of 30-60 μm.

[0010] Preferably, the solution treatment temperature is 515℃-525℃, and the holding time is 6h-10h; The solution treatment process also includes an air cooling process after the solution treatment.

[0011] Preferably, the aging treatment temperature is 180℃-190℃, and the holding time is 6h-8h.

[0012] Graphene is coated onto the surface of the heat-treated AlSi alloy powder to obtain graphene-coated AlSi alloy powder (graphene-AlSi). The coating method can be electrostatic adsorption, ball milling, co-deposition, chemical reduction, etc.

[0013] Preferably, the coating method is a chemical reduction method.

[0014] The chemical reduction process includes the following steps: 50-200 ml of a GO dispersion with a concentration of 0.1-0.3 mg / ml was placed in a suitable container, and graphene oxide was well dispersed in deionized water by ultrasonication and stirred for 30-90 min. Then, 10-20 g of AlSi10Mg alloy powder with a particle size of 30-50 μm was added to the GO dispersion, and stirring was continued for 20-30 min until the solution became transparent. Finally, after washing and vacuum drying, graphene-AlSi10Mg powder was obtained.

[0015] Preferably, the mass ratio of graphene to AlSi alloy powder is 0.15 wt.%. The graphene-AlSi alloy powder was subjected to selective laser melting to obtain a SiC-reinforced AlSi alloy.

[0016] Preferably, the parameters for selective laser melting are as follows: laser power of 300-400 W, laser moving speed of 800-1200 mm / s, scanning spacing of 40-70 μm, and powder thickness of 30-60 μm, to obtain SiC-G / AlSi10Mg alloy.

[0017] The SiC-reinforced AlSi alloy prepared by the method provided in this invention has at least the following beneficial effects: Heat treatment of AlSi alloy powder enhances silicon phase precipitation, providing a sufficient Si source for subsequent in-situ SiC formation. Using graphene-coated AlSi10Mg alloy powder as raw material, graphene serves as the carbon source, ensuring SiC formation and forming a micro / nano-scale SiC reinforcing phase. Furthermore, the coated graphene forms a three-dimensional network distributed along the alloy's grain boundaries, improving its toughness. Simultaneously, graphene oxide possesses excellent electrical conductivity and barrier properties; under its coating effect, AlSi10Mg metal may exhibit better conductivity and corrosion resistance in subsequent applications, thereby enhancing its performance and lifespan. Selective laser melting (SLM) is used as the forming method, with the laser providing instantaneous temperatures up to 3000℃ during the forming process, providing the energy for SiC formation. Attached Figure Description

[0018] Figure 1 Surface microstructure of graphene-attached AlSi10Mg powder Figure 2 Cross-sectional view of graphene-attached AlSi10Mg powder Figure 3 Raman curves of graphene attached to the surface of AlSi10Mg powder Figure 4 Metallographic structure of SiC-G / AlSi10Mg alloy formed by selective laser melting Figure 5 Scanning microstructure of SiC-G / AlSi10Mg alloy formed by selective laser melting Figure 6 Tensile curves of SiC-G / AlSi10Mg alloy formed by selective laser melting Figure 7 Microstructure of fracture surface after tensile testing of SiC-G / AlSi10Mg alloy formed by selective laser melting Figure 8 Polarization curves of SiC-G / AlSi10Mg alloy formed by selective laser melting in 3.5 wt.% NaCl solution Figure 9 Friction coefficient of SiC-G / AlSi10Mg alloy formed by selective laser melting Detailed Implementation

[0019] This invention provides a high-strength, high-conductivity selective-area laser melting-formed aluminum alloy, wherein the AlSi10Mg alloy contains two reinforcing phases: graphene and SiC.

[0020] Preferably, the graphene forms a three-dimensional network distributed on the interface of the aluminum alloy.

[0021] Preferably, the SiC is formed in situ and uniformly distributed in the alloy.

[0022] This invention provides a method for preparing the above-mentioned high-strength, high-conductivity aluminum alloy, comprising the following steps: The AlSi alloy powder was subjected to solution treatment and aging treatment in sequence to obtain an Al alloy with precipitated Si phase. Preferably, the solution treatment temperature is 510℃-550℃, which can be specifically 510℃, 520℃, 535℃, etc. in the embodiments, and the heat preservation time is 6h-10h, which can be specifically 6h, 8h, 10h in the embodiments. The solution treatment process also includes air cooling of the solution-treated powder.

[0023] Preferably, the aging treatment temperature is 180℃-190℃, and the holding time is 6h-8h. In the embodiments, the aging treatment temperature can be specifically 180℃, and the aging time can be specifically 6h or 8h. In this invention, the AlSi10Mg alloy can precipitate Si phase after heat treatment, which is beneficial to the subsequent formation of SiC strengthening phase.

[0024] Graphene is coated onto the surface of the heat-treated AlSi alloy powder to obtain graphene-coated AlSi alloy powder (G / AlSi). The coating methods include electrostatic adsorption, ball milling, co-deposition, and chemical reduction.

[0025] Preferably, the coating method is a chemical reduction method.

[0026] The chemical reduction method includes the following steps: 50-200 ml of a GO dispersion with a concentration of 0.1-0.3 mg / ml was placed in a suitable container, and graphene oxide was well dispersed in deionized water by ultrasonication and stirred for 30-90 min. Then, 10-20 g of AlSi10Mg alloy powder with a particle size of 30-50 μm was added to the GO dispersion, and stirring was continued for 20-30 min until the solution became transparent. Finally, after washing and vacuum drying, G / AlSi10Mg powder was obtained.

[0027] Preferably, the mass ratio of graphene to AlSi alloy powder is 0.15 wt.%. The graphene obtained using the above method is uniformly adhered to the surface of the alloy powder, providing a carbon source for the in-situ formation of uniformly distributed silicon carbide. Compared to ball milling or mechanical mixing methods, this method ensures uniformity. Besides the above method, other measures that can uniformly coat graphene onto the powder surface are also possible.

[0028] Preferably, graphene-coated AlSi alloy powder (G / AlSi) The G / AlSi alloy powder is subjected to selective laser melting to obtain a SiC-strengthened G / AlSi alloy (SiC-G / AlSi alloy).

[0029] The selected area laser melting forming parameters are as follows: laser power of 300-400 W, laser moving speed of 800-1200 mm / s, scanning spacing of 40-70 μm, and powder thickness of 30-60 μm, to obtain SiC-G / AlSi10Mg alloy.

[0030] The technical solution of the present invention will be better understood below with reference to specific embodiments. Example 1

[0031] High-strength, high-conductivity selective laser melting aluminum alloy, using three-dimensional network graphene and in-situ generated SiC as the reinforcing phases.

[0032] The preparation method of the above-mentioned high-strength and high-conductivity aluminum alloy includes: Step 1: Pretreatment of alloy powder. The powder is subjected to solution treatment and aging heat treatment sequentially. The solution treatment temperature and time are 520℃ for 15 min; the aging temperature and time are 180℃ for 2 h. After the solution treatment, the powder is air-cooled to room temperature before aging treatment.

[0033] Step 2: Preparation of graphene-AlSi alloy powder using a chemical reduction method: Prepare 100 ml of GO (graphene oxide) dispersion with a concentration of 0.1 mg / ml.

[0034] Graphene oxide is dispersed in deionized water by ultrasound and stirred for 30-90 minutes.

[0035] Add 20g of AlSi10Mg alloy powder with a particle size of 30-50μm to the GO dispersion and stir for 20-30 minutes until the solution becomes transparent. Graphene oxide and alloy powder undergo a reduction reaction to generate reduced graphene oxide (rGO, which will be referred to as G below for convenience).

[0036] The mixed solution was washed and vacuum dried to obtain 0.1 G-AlSi10Mg powder.

[0037] Step 3: Selective laser melting and forming of AlSi alloy 280g of G-AlSi10Mg powder was weighed and shaped using selective laser melting (SLM). The forming process parameters were set as follows: laser power of 360W, laser moving speed of 1000 mm / s, scanning spacing of 50μm, and powder thickness of 40μm to obtain SiC-G / AlSi10Mg alloy.

[0038] The sample obtained after molding was labeled as SiC-G / AlSi10Mg.

[0039] The microstructure of the SiC-G / AlSi10Mg alloy was analyzed to determine its impact on performance. The above steps describe in detail the entire process from alloy powder pretreatment to alloy bulk preparation. Each step is crucial to the success of the experiment and must be strictly followed to ensure the accuracy and reliability of the results.

[0040] Figure 1 , Figure 2 The images show the microstructure and cross-sectional views of 0.1 G-AlSi10Mg powder. The powder surface has a heavy hazy appearance, and obvious wrinkled nanosheets can be seen at the particle boundaries, which is typical of graphene morphology. The cross-sectional morphology shows a thin coating layer attached to the particle surface, which Raman analysis indicates to be redox graphene (e.g., graphene oxide). Figure 3 (As shown).

[0041] Figure 4 The metallographic morphology of SiC-0.1G / AlSi10Mg alloy formed by selective laser melting (SLM) is shown. The results clearly reveal continuous, fish-scale-like melt channels formed under the laser parameters, which overlap. However, obvious pores are still visible on the melt channels and in the adjacent overlapping areas, likely due to the vaporization of Mg.

[0042] Further magnification of the alloy's microstructure, such as... Figure 5 The image shown is a transmission electron microscopy (TEM) image of the alloy. The grain size distribution is uneven, with small grains predominating, ranging from approximately 250 to 500 nm. Black reinforcing phase SiC is clearly visible at the grain boundaries; this is due to the in-situ formation of graphene and the second-phase Si in the aluminum alloy under laser thermal irradiation. The generated SiC serves both as a strengthening agent and as a grain nucleus, refining the grain size. Example 2

[0043] High-strength, high-conductivity selective laser melting aluminum alloy, using three-dimensional network graphene and in-situ generated SiC as the reinforcing phases.

[0044] The preparation method of the above-mentioned high-strength and high-conductivity aluminum alloy includes: Step 1: Pretreatment of alloy powder. The powder is subjected to solution treatment and aging heat treatment sequentially. The solution treatment temperature and time are 520℃ for 15 min; the aging temperature and time are 180℃ for 2 h. After the solution treatment, the powder is air-cooled to room temperature before aging treatment.

[0045] Step 2: Preparation of graphene-AlSi alloy powder using a chemical reduction method: Prepare 200 ml of graphene oxide (GO) dispersion with a concentration of 0.15 mg / ml.

[0046] Graphene oxide is dispersed in deionized water by ultrasound and stirred for 30-90 minutes.

[0047] Add 20g of AlSi10Mg alloy powder with a particle size of 30-50μm to the GO dispersion and stir for 20-30 minutes until the solution becomes transparent. Graphene oxide and alloy powder undergo a reduction reaction to generate reduced graphene oxide (rGO, which will be referred to as G below for convenience).

[0048] The mixed solution was washed and vacuum dried to obtain 0.05 G AlSi10Mg powder.

[0049] Step 3: Selective laser melting and forming of AlSi alloy 280g of 0.15G-AlSi10Mg powder was weighed. Selective laser melting (SLM) was used to form the alloy. The forming process parameters were set as follows: laser power of 360W, laser moving speed of 1000 mm / s, scanning spacing of 50μm, and powder thickness of 40μm, to obtain a SiC-0.15G / AlSi10Mg alloy. Performance tests were performed on the SiC-G / AlSi10Mg alloy to evaluate its mechanical and electrical properties.

[0050] Figure 6 The tensile curves are shown for the alloy formed after coating with a small amount of graphene. The mechanical properties of the alloy formed after adding graphene are significantly enhanced and toughened, with the strength increasing to 454 MPa and the elongation increasing to 10.8%.

[0051] Figure 7 The image shows the microstructure of the fracture surface after tensile testing. The fracture surface is dark gray with obvious dimples surrounded by white ridges, i.e., tear ridges, indicating ductile fracture. This is related to the SiC strengthening phase and dislocations formed inside the alloy.

[0052] The conductivity test results show that the conductivity of the AlSi10Mg alloy formed by SLM is 24.8% IACS, which is lower than that of the national standard AlSi10Mg alloy. This is because the rapid solidification of SLM forming results in more fine grains and grain boundaries, which increases the resistance. After adding graphene, the conductivity is about 45% IACS, which is the beneficial effect of the conductive graphene remaining at the grain boundaries.

[0053] The above steps describe in detail the entire process from the pretreatment of alloy powder to the preparation of alloy bulk. Each step is crucial to the success of the experiment and must be strictly followed to ensure the accuracy and reliability of the experimental results. Example 3

[0054] High-strength, high-conductivity selective laser melting aluminum alloy, using three-dimensional network graphene and in-situ generated SiC as the reinforcing phases.

[0055] The preparation method of the above-mentioned high-strength and high-conductivity aluminum alloy includes the following experimental steps: Step 1: Pretreatment of alloy powder. The powder is subjected to solution treatment and aging heat treatment sequentially. The solution treatment temperature and time are 520℃ for 15 min; the aging temperature and time are 180℃ for 2 h. After the solution treatment, the powder is air-cooled to room temperature before aging treatment.

[0056] Step 2: Preparation of graphene-AlSi alloy powder by chemical reduction: Prepare 200 ml of GO (graphene oxide) dispersion with a concentration of 0.3 mg / ml.

[0057] Graphene oxide is dispersed in deionized water by ultrasound and stirred for 30-90 minutes.

[0058] Add 20g of AlSi10Mg alloy powder with a particle size of 30-50μm to the GO dispersion and stir for 20-30 minutes until the solution becomes transparent.

[0059] The mixed solution was washed and vacuum dried to obtain 0.3 G AlSi10Mg powder.

[0060] Step 3: Selective laser melting and forming of AlSi alloy 280g of 0.3G-AlSi10Mg powder was weighed. Selective laser melting (SLM) was used to form the alloy. The forming process parameters were set as follows: laser power of 360W, laser moving speed of 1000 mm / s, scanning spacing of 70μm, and powder thickness of 40μm, to obtain a SiC-0.3G / AlSi10Mg alloy.

[0061] The sample obtained after molding was labeled as SiC-0.3G / AlSi10Mg.

[0062] The corrosion resistance and tribological properties of the SiC-0.3G / AlSi10Mg alloy were tested.

[0063] Figure 8The polarization curves of the SiC-G / AlSi10Mg alloy formed by selective laser melting in 3.5 wt.% NaCl solution are shown. The polarization curves reveal that the self-corrosion potential of the alloy is around -0.68 V, which significantly improves corrosion resistance compared to the AlSi alloy (whose self-corrosion potential is around -1.2 V in the prior art). This indicates that after forming the alloy using graphene-modified powder as raw material, the in-situ formation of SiC leads to grain refinement, an increased proportion of grain boundaries, and disruption of the continuity of the aluminum matrix (e.g., ...). Figure 5 As shown in the figure, this leads to a slowdown in the corrosion rate and an enhanced corrosion resistance.

[0064] Figure 9 The friction coefficient of the SiC-G / AlSi10Mg alloy formed by selective laser melting is shown in Figure 1. The friction coefficient is stable at around 0.5 during the friction process, indicating that the in-situ generated SiC has a stabilizing effect on the wear resistance of the alloy.

[0065] The above steps describe in detail the entire process from aluminum alloy powder modification to final alloy preparation. Each step is crucial to the success of the experiment and must be strictly followed to ensure the accuracy and reliability of the experimental results.

[0066] The present invention has been described in detail above with reference to the embodiments. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

[0067] Comparative Example 1 The preparation process of AlSi alloy by selective laser forming is as follows:

[0068] Step 1: Preparation of graphene-AlSi alloy powder: Prepare 200 ml of GO (graphene oxide) dispersion with a concentration of 0.3 mg / ml.

[0069] Graphene oxide is dispersed in deionized water by ultrasound and stirred for 30-90 minutes.

[0070] Add 20g of AlSi10Mg alloy powder with a particle size of 30-50μm to the GO dispersion and stir for 20-30 minutes until the solution becomes transparent.

[0071] The mixed solution was washed and vacuum dried to obtain 0.3 G AlSi10Mg powder.

[0072] Step 3: Selective laser melting and forming of AlSi alloy 280g of G-AlSi10Mg powder was weighed and shaped using selective laser melting (SLM). The forming process parameters were set as follows: laser power of 360W, laser moving speed of 1000mm / s, scanning spacing of 70μm, and powder thickness of 40μm to obtain SiC-G / AlSi10Mg alloy.

[0073] The sample obtained after molding was labeled as Comparative Example 1-SiC-0.3G / AlSi10Mg. Compared to Example 3, the AlSi10Mg alloy powder used was not heat-treated.

[0074] Comparative Example 2 The preparation process of high-strength, high-conductivity selective-region laser melting aluminum alloy is as follows: Step 1: Pretreatment of alloy powder. The powder is subjected to solution treatment and aging heat treatment sequentially. The solution treatment temperature and time are 520℃ for 15 min; the aging temperature and time are 180℃ for 2 h. After the solution treatment, the powder is air-cooled to room temperature before aging treatment.

[0075] Step 2: Selective laser melting and forming of AlSi alloy 280g of heat-treated AlSi10Mg powder was weighed. Selective laser melting (SLM) was used to form the alloy. The forming process parameters were set as follows: laser power 360W, laser moving speed 1000mm / s, scanning spacing 50μm, and powder thickness 40μm to obtain the AlSi10Mg alloy.

[0076] The sample obtained after molding is labeled as Comparative Example 2. Compared with Examples 1 and 2, the aluminum alloy powder used in Comparative Example 2 is not coated with graphene.

Claims

1. A high-strength, high-conductivity AlSi10Mg alloy with uniform SiC distribution and its preparation method, characterized in that, The alloy is composed of AlSi10Mg and in-situ formed SiC, and its preparation includes the following steps: (1) Preparation of composite powder: AlSi alloy powder was subjected to solid solution and aging treatment to obtain a uniformly distributed second phase silicon. Graphene is attached to the surface of heat-treated AlSi alloy powder to obtain G-AlSi powder, which is used as a raw material for selective laser melting. (2) Selective laser melting: Using rGO / AlSi10Mg powder as raw material, the SiC-G / AlSi10Mg alloy is obtained by using parameters such as laser power of 300-400 W, laser moving speed of 800-1200 mm / s, scanning distance of 40-70μm and powder thickness of 30-60μm.

2. The method according to claim 1, characterized in that, The heat treatment process described in step (1) is a solution treatment time of 6-10h and a solution treatment temperature of 510-550℃; an aging time of 4-8h and an aging temperature of 160℃-200℃.

3. The method according to claim 1, characterized in that, The preparation methods of G-AlSi powder mentioned in step (1) include electrostatic adsorption, ball milling, co-deposition, chemical reduction and other methods.

4. The method according to claim 1, characterized in that, The preferred parameters for the selective laser forming process described in step (2) are: laser power of 360 W, laser moving speed of 1000 mm / s, scanning spacing of 60 μm, and powder thickness of 40 μm.

5. A high-strength, high-conductivity AlSi10Mg alloy with uniformly distributed SiC, characterized in that, Prepared by the method described in any one of claims 1-4, the alloy contains in-situ generated SiC reinforcing phase and network graphene uniformly distributed, wherein SiC plays a reinforcing role, while graphene can improve toughness and also play a role in electrical and thermal conductivity.

6. The high-strength, high-conductivity aluminum alloy according to claim 5, characterized in that, The alloy has a hardness ≥140HV, yield strength ≥380.9MPa, tensile strength ≥416MPa, elongation ≥5.6%, and electrical conductivity ≥40%IACS.

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