AlN / AlSiMg high-toughness aluminum alloy and preparation method thereof

Abstract

The invention provides an AlN / AlSiMg high-toughness aluminum alloy and a preparation method of the AlN / AlSiMg high-toughness aluminum alloy. The AlN / AlSiMg high-toughness aluminum alloy material comprises an aluminum matrix, eutectic silicon and in-situ authigenic AlN, the eutectic silicon and the AlN are dispersed in the aluminum matrix, the eutectic silicon is of a net-shaped structure, the particle size of the AlN is nanoscale, the AlN is of a net-shaped structure, and the net-shaped structure of the AlN and the net-shaped structure of the eutectic silicon are communicated with each other to form a composite net-shaped structure. The AlN / AlSiMg high-strength and high-toughness aluminum alloy disclosed by the invention has relatively high comprehensive mechanical properties.

Description

Technical Field

[0001] The present invention relates to the field of metal materials, and particularly to an AlN / AlSiMg high-strength and high-toughness aluminum alloy in which AlN and eutectic silicon form a composite network structure and a preparation method thereof. Background Art

[0002] Dispersion particle-reinforced metal matrix composites can significantly improve the strength, wear resistance and high-temperature performance of materials by introducing high-hardness ceramic particles into the metal matrix, and are widely used in the fields of aerospace, automobile manufacturing and high-end equipment.

[0003] However, the process of introducing high-hardness ceramic particles by traditional preparation technologies has certain limitations. For example, the interface bonding between the high-hardness ceramic and the metal matrix is weak, and the forming ability of complex structures is limited. Summary of the Invention

[0004] An object of the present invention is to provide an AlN / AlSiMg high-strength and high-toughness aluminum alloy material with high comprehensive mechanical properties and a preparation method thereof.

[0005] According to one aspect of the present invention, there is provided an AlN / AlSiMg high-strength and high-toughness aluminum alloy material, the AlN / AlSiMg high-strength and high-toughness aluminum alloy material includes an aluminum matrix, eutectic silicon, and in-situ grown AlN. The eutectic silicon and AlN are dispersed in the aluminum matrix. The eutectic silicon has a network structure. The particle size of AlN is nanoscale and has a network structure. The network structure of AlN is interconnected with the network structure of the eutectic silicon to form a composite network structure.

[0006] Optionally, the AlN / AlSiMg high-strength and high-toughness aluminum alloy material is formed by selective laser melting printing technology.

[0007] Optionally, the network width of the AlN network structure is greater than the network width of the eutectic silicon network structure. Among them, the shape of the network cell of the eutectic silicon is at least one of equiaxed and columnar. The network cell size of the eutectic silicon is 50 nm - 5 μm, the particle size of AlN is 5 nm - 200 nm, and the network cell size of AlN is 100 nm - 5 μm. Among them, the network cell size of the eutectic silicon network structure near the AlN network structure is smaller than the network cell size of the eutectic silicon network structure far from the AlN network structure.

[0008] Optionally, based on the total amount of the AlN / AlSiMg high-strength and high-toughness aluminum alloy material, the mass percentage of AlN is 0.5 wt% - 7.0 wt%, the mass percentage of Si is 7.0 wt% - 12.0 wt%, the mass percentage of Mg is 0.5 wt% - 3.0 wt%, the mass percentage of Al is 75.0 wt% - 92.0 wt%, and the balance is at least one of Cu, Mn, and Fe.

[0009] According to another aspect of the present invention, a method for preparing an AlN / AlSiMg high-strength and tough aluminum alloy material is provided. The preparation method includes: mixing raw materials to form a mixed powder, the raw materials including Al-N alloy powder and aluminum-silicon-magnesium powder; and using selective laser melting printing technology to print the mixed powder into a preset shape.

[0010] Optionally, the raw materials contain 5.0wt%-20.0wt% of Al-N alloy powder and 75.0wt%-95.0wt% of aluminum-silicon-magnesium powder by mass percentage. Based on the total mass of the Al-N alloy powder, the N content is 0.1wt%-4.0wt%. The particle size of the Al-N alloy powder is less than or equal to 1μm, and the particle size of the aluminum-silicon-magnesium powder is 30nm-75μm. The raw materials also contain at least one of Cu, Mn, and Fe.

[0011] Optionally, the step of forming the mixed powder includes putting the raw materials into a mixer and mixing for 18h-24h.

[0012] Optionally, the preparation method further includes: after forming the mixed powder, using a sieve to sieve out large particle size powders with a size greater than 50μm.

[0013] Optionally, the preparation method further includes: after sieving out large particle size powders with a size greater than 50μm, performing vacuum drying treatment on the mixed powder, with a vacuum degree of -0.1MPa-0MPa, a drying temperature of 70°C-90°C, and a drying time of 12h-24h.

[0014] Optionally, the step of using selective laser melting printing technology to print the mixed powder into a preset shape includes: preheating a pure aluminum or aluminum alloy substrate to 140°C-160°C; laying the mixed powder on the preheated pure aluminum or aluminum alloy substrate and melting the mixed powder using a laser, wherein the powder laying thickness is 30μm-50μm, the laser power is 250W-350W, the scanning speed is 1000mm / s-2000mm / s, and the scanning spacing is 60μm-120μm; repeating the steps of laying the mixed powder and melting the mixed powder until the preset shape is formed.

[0015] According to the present invention, AlN particles are in-situ generated, thus solving the problems of interface contamination and particle agglomeration easily caused by the external addition method. In addition, according to the present invention, both eutectic silicon and AlN are in a network shape and the network of eutectic silicon and the network of AlN are interconnected to form a composite network structure. Compared with the prior art where eutectic silicon is in a short rod shape and AlN is in a granular shape, on the one hand, it can ensure the effective transmission of the load, and on the other hand, by increasing the matrix material participating in bearing, stress concentration is reduced, and premature failure of the material can be effectively avoided, thereby significantly improving the tensile strength and elongation.

[0016] According to the present invention, the AlN / AlSiMg high-strength and high-toughness aluminum alloy material can be formed by selective laser melting printing technology. By using selective laser melting printing technology to in-situ generate AlN in the aluminum matrix, the problems of interfacial contamination and particle agglomeration easily caused by the external addition method can be solved, and AlN with smaller size can also be prepared. In addition, by using selective laser melting printing technology, the size, content and configuration of AlN can be effectively regulated by powder pretreatment and adjustment of printing parameters, increasing the degree of freedom of material configuration design.

[0017] According to the present invention, by comprehensively controlling the mass percentages of AlN, Si and Mg, the tensile strength and elongation can be significantly improved, thereby improving the comprehensive mechanical properties of the AlN / AlSiMg high-strength and high-toughness aluminum alloy material.

[0018] According to the present invention, by comprehensively controlling the powder spreading thickness, laser power, scanning speed and scanning spacing, it is beneficial to produce AlN / AlSiMg high-strength and high-toughness aluminum alloy materials with good surface quality and excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects, features and advantages of the present invention will become more clear through the following detailed description in conjunction with the drawings.

[0020] Figure 1 is a scanning electron microscope image of an AlN / AlSiMg high-strength and high-toughness aluminum alloy according to an embodiment of the present invention.

[0021] Figure 2 is Figure 1 a high-magnification microstructural image of the circular region in

[0022] Figure 3 is a graph of the strength and elongation of an AlN / AlSiMg high-strength and high-toughness aluminum alloy according to Embodiment 1 of the present invention.

[0023] Figure 4 is a schematic diagram of the sample size of an AlN / AlSiMg high-strength and high-toughness aluminum alloy according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The following detailed description is provided to assist the reader in obtaining a comprehensive understanding of the methods, apparatuses, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatuses, and / or systems described herein will be apparent after understanding the disclosure of the present disclosure. For example, the order of operations described herein is merely illustrative and is not limited to those set forth herein, but may be changed as will be apparent after understanding the disclosure of the present disclosure, except for operations that must occur in a specific order. In addition, descriptions of features known in the art may be omitted for greater clarity and conciseness.

[0025] The features described herein can be implemented in various forms and should not be construed as limited to the examples described herein. On the contrary, the examples described herein are provided only to illustrate some of the many possible ways of implementing the methods, apparatuses, and / or systems described herein, which will be apparent after understanding the disclosure of the present disclosure.

[0026] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs after understanding the present disclosure. Terms such as those defined in a general dictionary shall be interpreted to have a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and shall not be interpreted in an idealized or overly formal manner unless explicitly so defined herein.

[0027] As described in the background section, although it has been proven that introducing high-hardness ceramic particles into a metal matrix can improve the hardness, wear resistance, and high-temperature performance of the material, due to the limitations of existing processes, the interfacial bonding strength between the ceramic particles and the matrix is weak, so the reinforcing effect of the ceramic particles cannot be fully exerted. In addition, it is also difficult to form complex shapes. Therefore, an attempt is being made to find a way to fully exert the reinforcing effect of ceramic particles on the metal matrix.

[0028] AlN / AlSiMg high-strength and high-toughness aluminum alloy material To solve the above problems, the present invention provides an AlN / AlSiMg high-strength and tough aluminum alloy material, including an aluminum matrix, eutectic silicon, and in-situ grown AlN. The eutectic silicon and AlN are dispersed in the aluminum matrix. The eutectic silicon has a reticular structure. The size of AlN is nanoscale and has a reticular structure. The reticular structure of AlN is interconnected with the reticular structure of the eutectic silicon to form a composite reticular structure.

[0029] According to the present invention, AlN particles are grown in-situ, thus solving the problems of interfacial contamination and particle agglomeration easily caused by the external addition method. In addition, according to the present invention, both the eutectic silicon and AlN have a reticular shape and the reticular structure of the eutectic silicon is interconnected with the reticular structure of AlN to form a composite reticular structure. Compared with the prior art in which the eutectic silicon is in the shape of short rods and AlN is in the shape of particles, on the one hand, it can ensure the effective transfer of the load, and on the other hand, by increasing the matrix material participating in bearing, the stress concentration is reduced, and premature failure of the material can be effectively avoided, thereby significantly improving the tensile strength and elongation.

[0030] According to an embodiment of the present invention, the AlN / AlSiMg high-strength and high-toughness aluminum alloy material can be formed by selective laser melting printing technology. By using selective laser melting printing technology to in-situ generate AlN in the aluminum matrix, the problems of interfacial contamination and particle agglomeration easily caused by the external addition method can be solved, and AlN with a smaller size can also be prepared. In addition, by using selective laser melting printing technology, the size, content and configuration of AlN can be effectively regulated by powder pretreatment and adjustment of printing parameters, increasing the degree of freedom of material configuration design.

[0031] Figure 1 is a scanning electron microscope image of the AlN / AlSiMg high-strength and high-toughness aluminum alloy according to an embodiment of the present invention. Figure 2 is Figure 1 a high-magnification microstructural image of the circular region in

[0032] Figure 1 and Figure 2 The black regions shown in Figure 1 and Figure 2 are the aluminum matrix, and the gray reticular structure distributed on the aluminum matrix is AlN and eutectic silicon. Among them, multiple AlN particles enclose a reticular structure, and the eutectic silicon also encloses a reticular structure. From Figure 2 and

[0033] it can be seen that the mesh width of the AlN reticular structure is greater than that of the eutectic silicon reticular structure. In the composition analysis of point A (Point A) shown in Figure 1 and Figure 1 it can be detected that the N element, in addition, the atomic content of Al is too high because the EDS point analysis will be affected by the Al matrix and the Al content of AlN cannot be accurately measured. Figure 2 In addition, as shown in

[0034] and Figure 1 the shape of the cell of the eutectic silicon reticular structure can be at least one of equiaxed and columnar. Hereinafter, the cell refers to the basic unit reticular structure that encloses 360° in the reticular structure. As shown in

[0035] According to an embodiment of the present invention, based on the total amount of the AlN / AlSiMg high-strength and tough aluminum alloy material, the mass percentage of AlN is 0.5 wt% - 7.0 wt%, the mass percentage of Si is 7.0 wt% - 12.0 wt%, the mass percentage of Mg is 0.5 wt% - 3.0 wt%, the mass percentage of Al is 75.0 wt% - 92.0 wt%, and the balance is at least one of Cu, Mn, and Fe.

[0036] When, based on the total amount of the AlN / AlSiMg high-strength and tough aluminum alloy material, the mass percentage of AlN is less than 0.5 wt%, the effect of AlN strengthening the matrix may not be significant. When, based on the total amount of the AlN / AlSiMg high-strength and tough aluminum alloy material, the mass percentage of AlN is greater than 7.0 wt%, it may have an adverse effect on the elongation of the aluminum alloy.

[0037] As an example, based on the total amount of the AlN / AlSiMg high-strength and tough aluminum alloy material, the mass percentage of AlN can be 1.0 wt% - 6.0 wt%, 1.5 wt% - 5.5 wt%, or 2.5 wt% - 4.5 wt%.

[0038] When, based on the total amount of the AlN / AlSiMg high-strength and tough aluminum alloy material, the mass percentage of Si is less than 7.0 wt%, the heat resistance, corrosion resistance, and fluidity of the aluminum alloy according to the present invention may be insufficient. When, based on the total amount of the AlN / AlSiMg high-strength and tough aluminum alloy material, the mass percentage of Si is greater than 12.0 wt%, the precipitated primary silicon may reduce the plasticity of the aluminum alloy according to the present invention.

[0039] As an example, based on the total amount of the AlN / AlSiMg high-strength and tough aluminum alloy material, the mass percentage of Si can be 8.0 wt% - 11.0 wt% or 9.0 wt% - 10.0 wt%.

[0040] According to an embodiment of the present invention, based on the total amount of the AlN / AlSiMg high-strength and tough aluminum alloy material, by controlling the mass percentage of AlN to be 0.5 wt% - 7.0 wt%, the mass percentage of Si to be 7.0 wt% - 12.0 wt%, and the mass percentage of Mg to be 0.5 wt% - 3.0 wt%, the tensile strength and elongation can be significantly improved, thereby improving the comprehensive mechanical properties of the aluminum alloy.

[0041] Preparation method of AlN / AlSiMg high-strength and high-toughness aluminum alloy material The preparation method of the AlN / AlSiMg high-strength and tough aluminum alloy material according to an embodiment of the present invention may include: mixing raw materials to form a mixed powder, the raw materials including Al-N alloy powder and aluminum-silicon-magnesium powder; using selective laser melting printing technology to print the mixed powder into a preset shape.

[0042] According to an embodiment of the present invention, the Al-N alloy powder contains Al and N, wherein, based on the total mass of the Al-N alloy powder, the N content can be 0.1 wt% - 4.0 wt%. As an example, the particle size of the Al-N alloy powder can be less than or equal to 1 μm. If the particle size of the Al-N alloy powder is greater than 1 μm, when preparing the AlN / AlSiMg high-strength and tough aluminum alloy by using selective laser melting printing technology, there may be defects such as poor powder spreading uniformity and increased porosity, which will have an adverse impact on the comprehensive mechanical properties of the aluminum alloy. Additionally, as an example, the particle size of the Al-N alloy powder can be greater than or equal to 100 nm.

[0043] According to an embodiment of the present invention, the particle size of the aluminum-silicon-magnesium powder can be 30 nm - 75 μm. If the particle size of the aluminum-silicon-magnesium powder is less than 30 nm, it is easy to adhere and agglomerate with each other during the powder spreading process, which hinders the mutual movement of particles, has poor fluidity, and is likely to cause uneven powder spreading. If the particle size of the aluminum-silicon-magnesium powder is greater than 75 μm, there may be defects such as poor powder spreading uniformity and increased porosity. As an example, the particle size of the aluminum-silicon-magnesium powder can be 100 nm - 50 μm, 1 μm - 35 μm, or 10 μm - 20 μm.

[0044] According to the present invention, the raw materials contain 5.0 wt% - 20.0 wt% of Al-N alloy powder and 75.0 wt% - 95.0 wt% of aluminum-silicon-magnesium powder by mass percentage. In addition, the raw materials may further contain at least one of Cu, Mn, and Fe. As an example, at least one of Cu, Mn, and Fe may exist as impurities in the aluminum-silicon-magnesium powder or the Al-N alloy powder. However, the present invention is not limited thereto.

[0045] According to an embodiment of the present invention, the step of forming the mixed powder may include putting the raw materials into a mixer and mixing for 18 h - 24 h. If the mixing time is less than 18 h, the dispersion of the Al-N alloy powder in the aluminum-silicon-magnesium powder is uneven, which may lead to uneven distribution of AlN in AlSiMg. If the mixing time exceeds 24 h, it will cause energy loss.

[0046] According to an embodiment of the present invention, the method for preparing the AlN / AlSiMg high-strength and tough aluminum alloy material may further include: after forming the mixed powder, using a sieve to screen out the large-particle-size powder with a size greater than 50 μm. During the mixing process, the powder may adhere to each other again, thus possibly forming large particle sizes. By using a sieve to screen out the large-particle-size powder with a size greater than 50 μm, the defects of poor powder spreading uniformity and increased porosity can be avoided.

[0047] According to an embodiment of the present invention, after screening out the large-particle-size powder with a size greater than 50 μm, the mixed powder can be subjected to vacuum drying treatment, with a vacuum degree of -0.1 MPa - 0 MPa, a drying temperature of 70 °C - 90 °C, and a drying time of 12 h - 24 h.

[0048] According to an embodiment of the present invention, the specific steps of the selective laser melting printing technology may include: selecting pure aluminum or aluminum alloy as the substrate, preheating the pure aluminum or aluminum alloy substrate to 140°C - 160°C, and an inert gas may be introduced into the printing chamber to prevent powder oxidation; the mixed powder may be laid on the preheated pure aluminum or aluminum alloy substrate and the mixed powder may be melted using a laser to complete the first layer scanning; the steps of laying the mixed powder and melting the mixed powder using a laser are repeated until a preset shape is formed.

[0049] According to an embodiment of the present invention, when laying the mixed powder, the powder laying thickness may be 30μm - 50μm.

[0050] If the powder laying thickness is less than 30μm, the AlN network structure and the eutectic silicon network structure may not be effectively connected. If the powder laying thickness is greater than 120μm, the laser energy may not penetrate the powder layer, resulting in insufficient formation of the AlN network structure and the eutectic silicon network structure.

[0051] According to an embodiment of the present invention, when scanning the mixed powder, the laser power may be 250W - 350W. If the laser power is less than 250W, the Al-N alloy powder and the aluminum-silicon-magnesium powder may not be completely melted, resulting in internal pores, reduced density, and a significant decrease in tensile strength. If the laser power is greater than 350W, the molten pool formed by the Al-N alloy powder and the aluminum-silicon-magnesium powder will overheat, which may lead to defects such as spatter and increased surface roughness.

[0052] According to an embodiment of the present invention, when scanning the mixed powder, the scanning speed may be 1000mm / s - 2000mm / s. If the scanning speed is less than 1000mm / s, the molten pool formed by the Al-N alloy powder and the aluminum-silicon-magnesium powder will overheat, and the thermal stress of the formed aluminum alloy will increase, which has an adverse effect on the comprehensive mechanical properties of the aluminum alloy. If the scanning speed is greater than 2000mm / s, the interlayer bonding force is insufficient, which has an adverse effect on the mechanical properties.

[0053] According to an embodiment of the present invention, when scanning the mixed powder, the scanning spacing may be 60μm - 120μm. If the scanning spacing is less than 60μm, the molten pools formed by the Al-N alloy powder and the aluminum-silicon-magnesium powder will overlap excessively, resulting in the residue of spherical particles and a decrease in density. If the scanning spacing is greater than 120μm, the lap of the molten pools formed by the Al-N alloy powder and the aluminum-silicon-magnesium powder is insufficient, generating unfused pores, resulting in deterioration of mechanical properties.

[0054] According to the present invention, through a combined process with a powder spreading thickness of 30μm - 50μm, a laser power of 250W - 350W, a scanning speed of 1000mm / s - 2000mm / s, and a scanning pitch of 60μm - 120μm, it is beneficial to produce an AlN / AlSiMg high-strength and tough aluminum alloy material with good surface quality and excellent mechanical properties.

[0055] Hereinafter, specific embodiments according to the present invention will be described.

[0056] Example 1 (1) Prepare the required raw materials according to the following mass percentages: 5.0wt% of Al-N alloy powder (particle size ≤ 1μm), and the balance is aluminum-silicon-magnesium powder (particle size ≤ 75μm).

[0057] (2) After mixing the Al-N alloy powder and the aluminum-silicon-magnesium powder in step (1) for 20h, the pretreatment is completed.

[0058] (3) Sieve the mixed powder in step (2) with a sieve to remove large-particle-size powders with a size greater than 50μm, and then perform vacuum drying on the composite powder. The vacuum degree is 0MPa, the drying temperature is 80°C, and the drying time is 12h.

[0059] (4) After preheating the pure aluminum substrate to 150°C, introduce argon gas.

[0060] (5) First, spread powder on the preheated substrate and perform laser scanning. The powder spreading thickness is 30μm, the laser power is 250W, the scanning speed is 1000mm / s, and the scanning pitch is 60μm.

[0061] (6) After the laser completes the first layer of scanning, perform powder spreading and scanning again in the same manner until the sample size as shown in Figure 4 is completed. Figure 4 is a cross-sectional view of the sample, and the marked dimension unit is mm. The sample is in the shape of a thin sheet, and the thickness (i.e., the thickness in the direction perpendicular to the paper surface) is 3mm.

[0062] The AlN content in the AlN / AlSiMg aluminum alloy material obtained according to Example 1 is 1.5wt%, the size is 50nm, and it is distributed in a network shape. The network cell size is 100nm - 5μm. The eutectic silicon network cells are equiaxed in the area closer to the AlN network and columnar in the area farther from the AlN network, with a size of 1μm - 4μm, as shown in Figure 1 and Figure 2 shown.

[0063] The ultimate tensile strength of the AlN / AlSiMg aluminum alloy material obtained according to Example 1 can reach 487MPa, and the elongation is 3%. Therefore, it has high comprehensive mechanical properties, as shown in Figure 3 shown.

[0064] Example 2 (1) Prepare the required raw materials according to the following mass percentages: 10.0 wt% of Al-N alloy (particle size ≤ 0.5 μm), and the balance is aluminum-silicon-magnesium powder (particle size ≤ 50 μm).

[0065] (2) After mixing the Al-N alloy and the aluminum-silicon-magnesium powder in step (1) for 18 h, the pretreatment is completed.

[0066] (3) Sieving the mixed powder in step (2) with a sieve to remove large-particle-size powders with a size greater than 50 μm, and then subjecting the composite powder to vacuum drying treatment, with a vacuum degree of 0 MPa, a drying temperature of 80 °C, and a drying time of 16 h.

[0067] (4) After preheating the pure aluminum substrate to 150 °C, argon is introduced.

[0068] (5) First, spread the powder on the preheated substrate and perform laser scanning. The powder spreading thickness is 40 μm, the laser power is 275 W, the scanning speed is 1400 mm / s, and the scanning pitch is 80 μm.

[0069] (6) After the laser completes the first layer of scanning, powder spreading and scanning are carried out again in the same manner until the sample size as shown in Figure 4 is achieved.

[0070] The AlN content in the AlN / AlSiMg aluminum alloy material obtained according to Example 2 is 3 wt%, the size is 50 nm, and it is distributed in a network shape, with the network cell size being 200 nm - 2 μm. The eutectic silicon network cells are equiaxed, with a size of 1 μm - 2.5 μm.

[0071] Example 3 (1) Prepare the required raw materials according to the following mass percentages: 4.0 wt% of Al-N alloy (particle size ≤ 1 μm), and the balance is aluminum-silicon-magnesium powder (particle size ≤ 75 μm).

[0072] (2) After mixing the Al-N alloy and the aluminum-silicon-magnesium powder in step (1) for 18 h, the pretreatment is completed.

[0073] (3) Sieving the mixed powder in step (2) with a sieve to remove large-particle-size powders with a size greater than 50 μm, and then subjecting the composite powder to vacuum drying treatment, with a vacuum degree of 0 MPa, a drying temperature of 80 °C, and a drying time of 24 h.

[0074] (4) After preheating the pure aluminum substrate to 150 °C, argon is introduced.

[0075] (5) First, powder is spread on the preheated substrate and laser scanning is performed. The powder spreading thickness is 50 μm, the laser power is 350 W, the scanning speed is 2000 mm / s, and the scanning spacing is 120 μm.

[0076] (6) After the laser completes the first layer of scanning, powder spreading and scanning are carried out again in the same manner until the sample size as shown in Figure 4 is achieved.

[0077] The AlN content in the AlN / AlSiMg aluminum alloy material obtained according to Example 3 is 6 wt%, the size is 10 nm, and it is distributed in a network shape. The network cell size is 500 nm - 1 μm. The eutectic silicon network cells are equiaxed, with a size of 50 nm - 4 μm.

[0078] According to the embodiments of the present invention, beneficial effects not limited to the following description can be obtained.

[0079] According to the present invention, AlN particles are in-situ generated, thus solving the problems of interfacial contamination and particle agglomeration easily caused by the addition method. In addition, according to the present invention, both eutectic silicon and AlN are in a network shape and the network of eutectic silicon and the network of AlN are interconnected to form a composite network structure. Compared with the prior art where eutectic silicon is in a short rod shape and AlN is in a granular shape, on the one hand, it can ensure the effective transfer of load, and on the other hand, by increasing the matrix material participating in bearing, stress concentration is reduced, and premature failure of the material can be effectively avoided, thereby significantly improving the tensile strength and elongation.

[0080] According to the present invention, the AlN / AlSiMg high-strength and high-toughness aluminum alloy material can be formed by selective laser melting printing technology. By using selective laser melting printing technology to in-situ generate AlN in the aluminum matrix, the problems of interfacial contamination and particle agglomeration easily caused by the addition method can be solved, and AlN with a smaller size can also be prepared. In addition, by using selective laser melting printing technology, the size, content, and configuration of AlN can be effectively regulated through powder pretreatment and adjustment of printing parameters, increasing the degree of freedom in material configuration design.

[0081] According to the present invention, by comprehensively controlling the mass percentages of AlN, Si, and Mg, the tensile strength and elongation can be significantly improved, thereby improving the comprehensive mechanical properties of the AlN / AlSiMg high-strength and high-toughness aluminum alloy material.

[0082] According to the present invention, by comprehensively controlling the powder spreading thickness, laser power, scanning speed, and scanning spacing, it is beneficial to produce AlN / AlSiMg high-strength and high-toughness aluminum alloy materials with good surface quality and excellent mechanical properties.

[0083] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are only examples and do not limit the present invention, and the objectives of the present invention have been fully and effectively achieved. The functions and structural principles of the present invention have been demonstrated and explained in the embodiments, and without departing from the said principles, any variations or modifications can be made to the embodiments of the present invention.

Claims

1. An AlN / AlSiMg high-strength and tough aluminum alloy material, characterized in that, The high-strength and tough aluminum alloy material includes an aluminum matrix, eutectic silicon, and in-situ generated AlN. The eutectic silicon and AlN are dispersed in the aluminum matrix. The eutectic silicon has a reticular structure. The particle size of AlN is nanoscale and has a reticular structure. The reticular structure of AlN is interconnected with the reticular structure of the eutectic silicon to form a composite reticular structure.

2. The AlN / AlSiMg high-strength and tough aluminum alloy material according to claim 1, wherein The AlN / AlSiMg high-strength and tough aluminum alloy material is formed by selective laser melting printing technology.

3. The AlN / AlSiMg high-strength and tough aluminum alloy material according to claim 1, wherein The mesh width of the AlN reticular structure is greater than that of the eutectic silicon reticular structure. Among them, the shape of the network cells of the eutectic silicon is at least one of equiaxed and columnar. The size of the network cells of the eutectic silicon is 50 nm - 5 μm. The particle size of AlN is 5 nm - 200 nm. The size of the network cells of AlN is 100 nm - 5 μm. Among them, the size of the network cells of the eutectic silicon reticular structure close to the AlN reticular structure is smaller than that of the eutectic silicon reticular structure far from the AlN reticular structure.

4. The AlN / AlSiMg high-strength and tough aluminum alloy material according to claim 1, characterized in that, Based on the total amount of the AlN / AlSiMg high-strength and tough aluminum alloy material, the mass percentage of AlN is 0.5 wt% - 7.0 wt%, the mass percentage of Si is 7.0 wt% - 12.0 wt%, the mass percentage of Mg is 0.5 wt% - 3.0 wt%, the mass percentage of Al is 75.0 wt% - 92.0 wt%, and the balance is at least one of Cu, Mn, and Fe.

5. A preparation method of the AlN / AlSiMg high-strength and tough aluminum alloy material according to any one of claims 1 to 4, characterized in that, The preparation method includes: Mixing raw materials to form a mixed powder. The raw materials include Al-N alloy powder and aluminum-silicon-magnesium powder. Using selective laser melting printing technology to print the mixed powder into a preset shape.

6. The preparation method of the AlN / AlSiMg high-strength and tough aluminum alloy material according to claim 5, characterized in that, The raw materials contain 5.0 wt% - 20.0 wt% of Al-N alloy powder and 75.0 wt% - 95.0 wt% of aluminum-silicon-magnesium powder by mass percentage. Based on the total mass of the Al-N alloy powder, the N content is 0.1 wt% - 4.0 wt%. Among them, the particle size of the Al-N alloy powder is less than or equal to 1 μm, and the particle size of the aluminum-silicon-magnesium powder is 30 nm - 75 μm. Among them, the raw materials also include at least one of Cu, Mn, and Fe.

7. The preparation method of the AlN / AlSiMg high-strength and tough aluminum alloy material according to claim 5, characterized in that, The step of forming the mixed powder includes putting the raw materials into a mixer and mixing for 18 h - 24 h.

8. The preparation method of the AlN / AlSiMg high-strength and tough aluminum alloy material according to claim 5, characterized in that The preparation method also includes: after forming the mixed powder, using a sieve to screen out large-particle-size powders with a size greater than 50 μm.

9. The preparation method of the AlN / AlSiMg high-strength and tough aluminum alloy material according to claim 8, characterized in that, The preparation method also includes: after screening out large-particle-size powders with a size greater than 50 μm, performing vacuum drying treatment on the mixed powder. The vacuum degree is -0.1 MPa - 0 MPa, the drying temperature is 70 °C - 90 °C, and the drying time is 12 h - 24 h.

10. The preparation method of the AlN / AlSiMg high-strength and tough aluminum alloy material according to claim 5, characterized in that, The step of using selective laser melting printing technology to print the mixed powder into a preset shape includes: Preheating a pure aluminum or aluminum alloy substrate to 140 °C - 160 °C. Laying the mixed powder on the preheated pure aluminum or aluminum alloy substrate and melting the mixed powder with a laser. Among them, the powder laying thickness is 30 μm - 50 μm, the laser power is 250 W - 350 W, the scanning speed is 1000 mm / s - 2000 mm / s, and the scanning spacing is 60 μm - 120 μm. Repeat the steps of laying the mixed powder and melting the mixed powder until a preset shape is formed.

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