A eutectic strengthening Al-Mg-Si-Ni alloy material, a preparation method and application thereof

Abstract

The application discloses a eutectic strengthening Al-Mg-Si-Ni alloy material and a preparation method and application thereof. The alloy composition comprises 4.5-5.5 wt% of Mg, 1.8-2.8 wt% of Si, 0.5-2.5 wt% of Ni, and the balance of Al and inevitable impurities. The alloy material is prepared by a gas atomization method, Al-Mg-Si-Ni powder with a particle size range of 15-53 mu m is used as raw material, and the LPBF technology is used for preparation, so that the rapid forming of the high strength and toughness alloy is realized. The alloy is based on the synergistic strengthening of eutectic Al-Mg2Si and Al3Ni, the liquid filling capacity is greatly reduced by the eutectic phase to reduce the cracking tendency of the alloy material, and meanwhile, the content of eutectic cellular structure in the alloy can be further optimized and controlled through process parameters and component optimization, so that the formability and mechanical properties are optimized. The alloy material provided by the application has good formability, high density and excellent mechanical properties, and can be applied to turbine blades of an aero-engine.

Description

Technical Field

[0001] This invention relates to a high-strength and high-toughness aluminum alloy material, specifically to a eutectic strengthened Al-Mg-Si-Ni alloy material, its preparation method, and its application, belonging to the field of new material preparation technology. Background Technology

[0002] Aluminum alloy structural materials are widely used in aerospace, transportation, and chemical industries due to their low density, good mechanical properties, ease of processing, and excellent corrosion resistance. Currently, traditional methods such as casting, welding, forging, and powder metallurgy are commonly used to process aluminum alloys, but these methods have long development cycles and low design freedom. Laser powder bed melting (LPBF) technology is considered one of the most promising additive manufacturing (AM) technologies, offering greater design flexibility, reducing processing costs and shortening production cycles. It can be used for near-net-shape forming of complex aluminum alloy structural components with high dimensional accuracy. However, during LPBF, the extremely high rapid cooling temperature easily generates significant thermal stress, increasing the aluminum alloy's tendency to thermal crack and significantly impacting its formability, thus limiting the variety of commercially available aluminum alloys. While Al-Si alloys generally offer good formability, their mechanical properties are lacking, making them unsuitable for the high strength and toughness requirements of current industrial applications. Conversely, common high-strength and high-toughness 2-series, 6-series, and 7-series aluminum alloys suffer from poor formability. Conventional methods of adding precious metals like Sc and Zr, or ceramic particles like TiB2 and SiC to improve formability, increase industrial costs, hindering large-scale industrial production. Therefore, developing a novel high-strength and high-toughness aluminum alloy for complex components that offers good formability and low cost is of great significance. Summary of the Invention

[0003] To address the problems existing in the prior art, the first objective of this invention is to provide a eutectic strengthened Al-Mg-Si-Ni alloy material. The eutectic cellular structure composed of Al-Mg2Si and Al3Ni in the microstructure of this alloy material can improve the liquid filling capacity to a certain extent and significantly reduce the cracking tendency of the alloy material. At the same time, the synergistic strengthening of Al-Mg2Si and Al3Ni eutectic ensures the excellent formability and mechanical properties of the alloy material.

[0004] The second objective of this invention is to provide a method for preparing eutectic reinforced Al-Mg-Si-Ni alloy materials. This method uses Al-Mg-Si-Ni alloy powder prepared by gas atomization. Based on the synergistic effect of the components among the raw materials, the LPBF process is adopted. By optimizing the process parameters and composition, the content of cellular eutectic in the alloy structure is further controlled, thereby controlling the formability and mechanical properties of the material. Finally, rapid forming of high-strength and tough alloys is achieved.

[0005] The third objective of this invention is to provide an application of a eutectic-strengthened Al-Mg-Si-Ni alloy material for the fabrication of turbine blades. The alloy material provided by this invention is based on the semi-coherent interaction between the strengthening phase Mg2Si and the matrix in the cellular eutectic, and the coherent interaction between the strengthening phase Al3Ni and the matrix. The size and content of the cellular eutectic in the alloy microstructure are controlled by LPBF process parameters. A higher cooling rate increases undercooling, which to some extent improves the supersaturation effect. Better solid solution results in smaller and denser cellular eutectic sizes, optimizing the material's formability to achieve high density. Taking laser power as an example, the optimized laser power achieves good powder laser metallurgy effects and minimizes the evaporation of low-melting-point metal elements (Mg). If the laser power is too low, unmelted powder is likely to appear due to the high melting point of alumina; while excessively high laser power can lead to defects such as keyholes and pores. This alloy material achieves high density and synergistic strength and toughness without the need for additional precious metal elements or ceramic particles. Testing revealed that the alloy material provided by this invention has a relative density of 99.7%, extremely high density, no defects such as cracks or pores, a maximum tensile strength of 568.9 MPa, a yield strength of 434.7 MPa, and an elongation of 12.18%, meeting the performance requirements of turbine blades.

[0006] To achieve the above-mentioned technical objectives, this invention provides a method for preparing eutectic strengthened Al-Mg-Si-Ni alloy materials. The method involves melting an Al-Mg-Si-Ni alloy ingot and then atomizing it to obtain Al-Mg-Si-Ni alloy powder. The Al-Mg-Si-Ni alloy powder is then uniformly layered onto a substrate and formed using LPBF (Liquid Polymerization-Based Fiber) molding. The nano-strengthening phase of the Al-Mg-Si-Ni alloy material consists of a main strengthening phase Al-Mg2Si and a secondary strengthening phase Al3Ni.

[0007] As a preferred embodiment, the Al-Mg-Si-Ni alloy powder comprises the following components by mass percentage: 4.5–5.5% Mg, 1.8–2.8% Si, 0.5–2.5% Ni, with the balance being Al.

[0008] The raw material ratios used in this invention must be strictly followed according to the above requirements. If the proportion of Mg added is too small, it will reduce the solid solution strengthening effect of Mg on the alloy, resulting in a loss of strength. If the proportion of Mg added is too large, the chemically active Mg element will increase the nitrogen and hydrogen absorption tendency of Al, increasing the porosity defects in the printed parts. If the proportion of Si added is too small, it will reduce the eutectic phase, thereby affecting the liquid filling capacity and reducing the forming performance. If the proportion of Si added is too large, it exists in a free silicon state, which is hard and brittle, reducing the plasticity of the material. If the proportion of Ni added is too small, the content of Al3Ni strengthening phase will be greatly reduced, which will have a certain impact on the density and strength of the material. If the proportion of Ni added is too large, it will form needle-like AlFeNi phase with Fe impurities in the alloy, reducing mechanical properties and affecting hot cracking resistance.

[0009] As a preferred embodiment, the particle size of the Al-Mg-Si-Ni alloy powder is 15–53 μm.

[0010] As a preferred embodiment, the median particle size of the Al-Mg-Si-Ni alloy powder is 24–28 μm.

[0011] As a preferred embodiment, the main parameters of the LPBF technology process are as follows: under a protective atmosphere, laser power is 290-330W, laser scanning speed is 900-1100mm / s, scanning spacing is 0.1-0.12mm, scanning strategy is that the scanning direction of adjacent two layers is 60-80° apart, powder thickness is 0.01-0.03mm, and substrate temperature is 70-80℃.

[0012] As a preferred embodiment, when the mass percentage of Mg in the Al-Mg-Si-Ni alloy material is 5.0-5.5%, the main parameters of the LPBF technology process are as follows: under a protective atmosphere, laser power 300-320W, laser scanning speed 950-1050mm / s, scanning spacing 0.1-0.11mm, scanning strategy with a scanning direction interval of 65-70° between adjacent layers, powder thickness 0.02-0.03mm, and substrate temperature 70-75℃.

[0013] As a preferred embodiment, the Al-Mg-Si-Ni alloy material is composed of the following components by mass percentage: 5.0% Mg, 2.2% Si, 1.7% Ni, with the balance being Al. The main parameters of its LPBF technology process are: laser power 310W, laser scanning speed 900mm / s, scanning spacing 0.1mm, scanning strategy with a 67° interval between the scanning directions of adjacent layers, powder thickness 0.02mm, and substrate temperature 70℃.

[0014] The preparation method provided by this invention uses Al-Mg-Si-Ni alloy powder prepared by gas atomization and employs the LPBF process. By optimizing process parameters and composition, the size and content of eutectic in the alloy microstructure can be further controlled. Under the synergistic effect of laser power, scanning rate and other process parameters, the high cooling rate of the LPBF process increases the undercooling, which to a certain extent improves the supersaturation. The better the solid solution effect, the smaller the size and the higher the density of the cellular eutectic, thereby controlling the formability and mechanical properties of the material, and finally realizing the rapid forming of high-strength and tough alloys.

[0015] As a preferred embodiment, the protective atmosphere is high-purity nitrogen and / or high-purity argon.

[0016] The present invention also provides a eutectic strengthened Al-Mg-Si-Ni alloy material, obtained by any of the preparation methods described above.

[0017] As a preferred embodiment, the main strengthening phase Al-Mg2Si and the secondary strengthening phase Al3Ni in the Al-Mg-Si-Ni alloy material constitute a eutectic cellular structure.

[0018] As a preferred embodiment, the main reinforcing phase Al-Mg2Si has a particle size of 200–300 nm, and the auxiliary reinforcing phase Al3Ni has a particle size of 100–200 nm.

[0019] As a preferred embodiment, in the Al-Mg-Si-Ni alloy material, Mg2Si is semi-coherent with the Al matrix, and Ni elements are dispersed around the eutectic cellular structure, coherent with the Al matrix. This semi-coherent and coherent interface effectively hinders dislocation movement, exhibiting a strengthening effect. Mg2Si is semi-coherent with the Al matrix, and Mg2Si is a deformable particle; when dislocations cut through the particles, they cause atomic misalignment on the slip surface, requiring additional work and hindering dislocation movement, thus strengthening the alloy. Al3Ni is coherent with the matrix, and the interface possesses good thermal and mechanical stability. Furthermore, it can hinder dislocation movement through the Orovan mechanism, exhibiting a strengthening effect and improving the overall mechanical properties of the material. It is precisely based on the synergistic effect of coherent and semi-coherent structures that the material simultaneously possesses excellent strength and toughness.

[0020] This invention also provides an application of eutectic strengthened Al-Mg-Si-Ni alloy material, characterized in that it is used to prepare turbine blades for aero-engines.

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

[0022] 1) The alloy material provided by the present invention has excellent liquid filling ability due to the synergistic effect between the components. On the one hand, it ensures the formability of the alloy material and reduces bubbles while improving the density of the material. On the other hand, the fine grains enable the alloy material to have excellent mechanical properties and greatly improve the strength and toughness of the material.

[0023] 2) In the preparation method provided by the present invention, the Al-Mg-Si-Ni alloy powder prepared by gas atomization is further controlled by LPBF process through process parameter and composition optimization to control the size and content of cellular eutectic in the alloy structure, thereby controlling the formability and mechanical properties of the material, and finally realizing the rapid forming of high strength and toughness alloy.

[0024] 3) The alloy material provided in this invention achieves high density and toughness based on the semi-coherent interaction between Mg2Si and the matrix, and the coherent interaction between Al3Ni and the matrix, without the need for additional precious metal elements or ceramic particles. Testing shows that the alloy material provided by this invention has a relative density of 99.7%, is free of cracks and porosity, has a maximum tensile strength of 568.9 MPa, a yield strength of 434.7 MPa, and an elongation of 12.18%, meeting the performance requirements of turbine blades. Attached Figure Description

[0025] Figure 1 The image shows the microstructure of the Al-Mg-Si-Ni alloy powder described in Example 2.

[0026] Figure 2 Metallographic images of the Al-Mg-Si-Ni alloys described in Example 2 and Comparative Example 1;

[0027] Figure 3 TEM image of the Al-Mg-Si-Ni alloy described in embodiment 2;

[0028] Figure 4 The turbine blade prepared in Example 2. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. Obviously, the specific embodiments of the present invention should not be considered limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications or substitutions should be considered within the scope of protection of the present invention.

[0030] Example 1

[0031] Al-Mg-Si-Ni alloy parts were fabricated using the LPBF process. The Al-Mg-Si-Ni alloy powder had the following mass percentage composition: 5.3% Mg, 2.1% Si, 1.55% Ni, with the balance being Al. The particle size distribution of the Al-Mg-Si-Ni alloy powder was 15-53 μm, with a median particle size of 28 μm. The alloy powder was vacuum dried at 80℃ for 8 hours. The vacuum-dried alloy powder was then uniformly layered onto a substrate, and the parts were printed according to a 3D model to obtain complex components. The printing parameters were: laser power 290W, laser scanning speed 1100 mm / s, scanning spacing 0.1 mm, scanning strategy with a 67° interval between adjacent layers, powder thickness 0.02 mm, substrate temperature 70℃, and pure argon as the protective gas.

[0032] The alloy for printing parameters has a relative density of 99.3%, a maximum tensile strength of 548.5 MPa, a yield strength of 411.8 MPa, and an elongation of 10.68%.

[0033] Example 2

[0034] Al-Mg-Si-Ni alloy parts were fabricated using the LPBF process. The Al-Mg-Si-Ni alloy powder had the following mass percentage composition: 5.0% Mg, 2.2% Si, 1.7% Ni, with the balance being Al. The particle size distribution of the Al-Mg-Si-Ni alloy powder was 15-53 μm, with a median particle size of 28 μm. The alloy powder was vacuum dried at 80℃ for 8 hours. The vacuum-dried alloy powder was then uniformly layered onto a substrate, and the parts were printed according to a 3D model to obtain complex components. The printing parameters were: laser power 310W, laser scanning speed 900 mm / s, scanning spacing 0.1 mm, scanning strategy with a 67° interval between adjacent layers, powder thickness 0.02 mm, substrate temperature 70℃, and pure argon as the protective gas.

[0035] The alloy for printing parameters has a relative density of 99.7%, a maximum tensile strength of 568.9 MPa, a yield strength of 434.7 MPa, and an elongation of 12.18%.

[0036] Example 3

[0037] Al-Mg-Si-Ni alloy parts were fabricated using the LPBF process. The Al-Mg-Si-Ni alloy powder had the following mass percentage composition: 4.7% Mg, 1.8% Si, 0.9% Ni, with the balance being Al. The particle size distribution of the Al-Mg-Si-Ni alloy powder was 15-53 μm, with a median particle size of 28 μm. The alloy powder was vacuum dried at 80℃ for 8 hours. The vacuum-dried alloy powder was then uniformly layered onto a substrate, and the parts were printed according to a 3D model to obtain complex components. The printing parameters were: laser power 300W, laser scanning speed 1000 mm / s, scanning spacing 0.12 mm, scanning strategy with a 67° interval between adjacent layers, powder thickness 0.02 mm, substrate temperature 70℃, and pure argon as the protective gas.

[0038] The alloy for printing parameters has a relative density of 99.1%, a maximum tensile strength of 540.6 MPa, a yield strength of 390.5 MPa, and an elongation of 10.13%.

[0039] Comparative Example 1

[0040] Al-Mg-Si-Ni alloy parts were fabricated using the LPBF process. The Al-Mg-Si-Ni alloy powder had the following mass percentage composition: 4.2% Mg, 1.5% Si, 0.8% Ni, with the balance being Al. The particle size distribution of the Al-Mg-Si-Ni alloy powder was 15-53 μm, with a median particle size of 28 μm. The alloy powder was vacuum dried at 80℃ for 8 hours. The vacuum-dried alloy powder was then uniformly layered onto a substrate, and the parts were printed according to a 3D model to obtain complex components. The printing parameters were: laser power 290W, laser scanning speed 1300 mm / s, scanning spacing 0.1 mm, scanning strategy with a 67° interval between adjacent layers, powder thickness 0.02 mm, substrate temperature 70℃, and pure argon as the protective gas.

[0041] The alloy for printing parameters has a relative density of 94.8%, a maximum tensile strength of 452.8 MPa, a yield strength of 351.7 MPa, and an elongation of 7.67%.

[0042] Comparative Example 2

[0043] Al-Mg-Si-Ni alloy parts were fabricated using the LPBF process. The Al-Mg-Si-Ni alloy powder had the following mass percentage composition: 5.9% Mg, 2.8% Si, 2.3% Ni, with the balance being Al. The particle size distribution of the Al-Mg-Si-Ni alloy powder was 15-53 μm, with a median particle size of 28 μm. The alloy powder was vacuum dried at 80℃ for 8 hours. The vacuum-dried alloy powder was then uniformly layered onto a substrate, and the parts were printed according to a 3D model to obtain complex components. The printing parameters were: laser power 350W, laser scanning speed 800 mm / s, scanning spacing 0.1 mm, scanning strategy with a 67° interval between adjacent layers, powder thickness 0.02 mm, substrate temperature 70℃, and pure argon as the protective gas.

[0044] The alloy for printing parameters has a relative density of 93.2%, a maximum tensile strength of 400.3 MPa, a yield strength of 294.8 MPa, and an elongation of 6.08%.

[0045] Comparative Example 3

[0046] Al-Mg-Si-Ni alloy parts were fabricated using the LPBF process. The Al-Mg-Si-Ni alloy powder had the following mass percentage composition: 4.3% Mg, 1.9% Si, 0.6% Ni, with the balance being Al. The particle size distribution of the Al-Mg-Si-Ni alloy powder was 15-53 μm, with a median particle size of 28 μm. The alloy powder was vacuum dried at 80℃ for 8 hours. The vacuum-dried alloy powder was then uniformly layered onto a substrate, and the parts were printed according to a 3D model to obtain complex components. The printing parameters were: laser power 330W, laser scanning speed 1300 mm / s, scanning spacing 0.12 mm, scanning strategy with a 67° interval between adjacent layers, powder thickness 0.02 mm, substrate temperature 70℃, and pure argon as the protective gas.

[0047] The alloy for printing parameters has a relative density of 95.3%, a maximum tensile strength of 433.9 MPa, a yield strength of 345.3 MPa, and an elongation of 8.08%.

[0048] Table 1

[0049]

[0050] Table 1 shows the performance results of each embodiment and comparative example. The relative density of the materials obtained in Examples 1-3 is all above 99.0%. Figure 2 (a) It can be seen that the metallographic image of the material obtained in Example 2 shows high density and no defects such as cracks or voids. Figure 2 (b) It can be seen that in Comparative Example 1, due to the low content of Mg and Si and the high laser scanning speed, the resulting material has a large number of voids and defects of different sizes, which leads to a significant decrease in its density and performance. Furthermore, in Comparative Example 2, the content of Mg and Si is too high and the laser power is too high; in Comparative Example 3, the content of Mg, Si and Ni is too low and the laser scanning speed is too high. It can be seen that the changes in the material ratio and process parameters must be carried out within the range provided by the present invention. Only in the technical solution provided by the present invention can the alloy material utilize the excellent liquid fluidity of cellular eutectic to improve the alloy's forming performance, reduce the generation of cracks and pores, and enable the formed alloy to achieve the purpose of strong and tough bonding.

[0051] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. It should be noted that for those skilled in the art, within the scope of the technical principles of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a eutectic-strengthened Al-Mg-Si-Ni alloy material, characterized in that: Al-Mg-Si-Ni alloy powder is obtained by melting Al-Mg-Si-Ni alloy ingots and then atomizing them. The Al-Mg-Si-Ni alloy powder is then uniformly spread layer by layer on a substrate and formed by LPBF. The nano-reinforcing phase of the Al-Mg-Si-Ni alloy material consists of the main reinforcing phase Al-Mg2Si and the auxiliary reinforcing phase Al3Ni. The Al-Mg-Si-Ni alloy powder is composed of the following components by mass percentage: 4.5~5.5% Mg, 1.8~2.8% Si, 0.5~2.5% Ni, and the balance is Al. The main parameters of the LPBF technology process are as follows: under a protective atmosphere, the laser power is 290~330W, the laser scanning speed is 900~1100mm / s, the scanning spacing is 0.1~0.12mm, the scanning strategy is that the scanning direction of adjacent two layers is 60~80° apart, the powder thickness is 0.01~0.03mm, and the substrate temperature is 70~80℃.

2. The method for preparing a eutectic strengthened Al-Mg-Si-Ni alloy material according to claim 1, characterized in that: The particle size of the Al-Mg-Si-Ni alloy powder is 15~53μm.

3. The method for preparing a eutectic strengthened Al-Mg-Si-Ni alloy material according to claim 1, characterized in that: The median particle size of the Al-Mg-Si-Ni alloy powder is 24~28 μm.

4. The method for preparing a eutectic strengthened Al-Mg-Si-Ni alloy material according to claim 1, characterized in that: When the mass percentage of Mg in the Al-Mg-Si-Ni alloy material is 5.0~5.5%, the main parameters of the LPBF technology process are as follows: under a protective atmosphere, laser power 300~320W, laser scanning speed 950~1050mm / s, scanning spacing 0.1~0.11mm, scanning strategy with a scanning direction interval of 65~70° between adjacent layers, powder thickness 0.02~0.03mm, and substrate temperature 70~75℃.

5. The method for preparing a eutectic strengthened Al-Mg-Si-Ni alloy material according to claim 1, characterized in that: The Al-Mg-Si-Ni alloy material is composed of the following components by mass percentage: 5.0% Mg, 2.2% Si, 1.7% Ni, with the balance being Al. The main parameters of its LPBF technology process are: laser power 310W, laser scanning speed 900mm / s, scanning spacing 0.1mm, scanning strategy with a 67° interval between adjacent layers, powder thickness 0.02mm, and substrate temperature 70℃.

6. A method for preparing a eutectic strengthened Al-Mg-Si-Ni alloy material according to any one of claims 3 to 5, characterized in that: The protective atmosphere is high-purity nitrogen and / or high-purity argon.

7. A eutectic strengthened Al-Mg-Si-Ni alloy material, characterized in that: Obtained by the preparation method according to any one of claims 1 to 6.

8. The eutectic strengthened Al-Mg-Si-Ni alloy material according to claim 7, characterized in that: In the Al-Mg-Si-Ni alloy material, the main reinforcing phase Al-Mg2Si and the auxiliary reinforcing phase Al3Ni constitute a eutectic cellular structure; the particle size of the main reinforcing phase Al-Mg2Si is 200~300nm, and the particle size of the auxiliary reinforcing phase Al3Ni is 100~200nm.

9. The eutectic strengthened Al-Mg-Si-Ni alloy material according to claim 7, characterized in that: In the Al-Mg-Si-Ni alloy material, Mg2Si is semi-coherent with the Al matrix, and Ni element is dispersed around the eutectic cellular structure, coherent with the Al matrix.

10. The application of the eutectic strengthened Al-Mg-Si-Ni alloy material according to any one of claims 7 to 9, characterized in that: Used to manufacture turbine blades for aircraft engines.

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