An aluminum alloy armature material, its preparation method and application

Abstract

An aluminum alloy armature material, its preparation method and application belong to the technical field of aluminum alloy materials; the chemical composition of the aluminum alloy armature material includes, by mass fraction: Si: 0.24% - 4.8%, Mg: 0.597% - 0.697%, RE: 6% - 9.8%, and the rest are Al and inevitable impurities; the microstructure of the aluminum alloy armature material includes: a skeleton phase distributed in a network-like structure in the aluminum matrix and a wear-resistant phase dispersed in the aluminum matrix, the skeleton phase includes an Al-RE compound phase, and the wear-resistant phase includes an Mg2Si phase; by controlling each chemical component, a skeleton phase of Al-RE compounds and a wear-resistant phase of Mg2Si are formed in the aluminum matrix, making the aluminum alloy armature material have the characteristics of low density, high specific strength, good wear resistance, good electrical conductivity, and excellent room-temperature mechanical properties.

Description

Technical Field

[0001] The present application relates to the technical field of aluminum alloy materials, and in particular, to an aluminum alloy armature material, a preparation method thereof, and an application thereof. Background Art

[0002] As a new concept kinetic energy weapon that uses electromagnetic force to accelerate macroscopic projectiles to ultra-high speeds, the electromagnetic railgun has the advantages of simple structure, fast response, huge projectile energy, high firing accuracy, long range, good safety and concealment, etc. Moreover, the firing current can be adjusted for projectile energy customization for different targets, and it has great military potential in fields such as aerospace defense. As the electromagnetic railgun gradually develops towards actual combat applications, its service life has become one of the technical difficulties that are difficult to break through. The armature is the core component of the railgun and the only moving part in the system. During the electromagnetic rail launch process, the current level is high, the armature moves very fast, and the duration is extremely short. At this time, the sliding electrical contact state between the armature and the rail is extremely poor. There are not only mechanical phenomena such as friction and wear, edge groove erosion, high-speed planing, material softening, and tension deformation on the contact surface, but also a series of electrical behaviors such as resistive heat and arc ablation, and there are complex interactions between them. Therefore, improving the comprehensive performance of the armature material and suppressing the failure of the armature material have become the key to ensuring the firing accuracy, service life, and utilization rate of the electromagnetic railgun.

[0003] Combined with the heating mechanism of the electromagnetic rail armature, the selection of the armature material generally should be considered from the following three aspects: First, the density of the armature material should be low to reduce the mass of the armature and improve the launch efficiency; second, the armature material should be able to withstand high temperatures and have a high energy absorption rate to increase the critical temperature of contact point transfer and prevent the generation of arcs; third, the conductivity should be high to reduce the generation of ohmic heat. Currently, aluminum alloys with relatively low density are usually used as the armature material. However, the aluminum alloy conductor materials reported currently still cannot exhibit good comprehensive service performance under the harsh service conditions of the electromagnetic railgun armature material. Without significantly reducing the thermal conductivity and electrical conductivity, the strength and wear resistance of the material still cannot meet the actual combat requirements of the electromagnetic railgun. Summary of the Invention

[0004] The purpose of the present application is to provide an aluminum alloy armature material, a preparation method thereof, and an application thereof, which improve the wear resistance of the aluminum alloy armature material.

[0005] In a first aspect, an embodiment of the present application provides an aluminum alloy armature material. The chemical composition of the aluminum alloy armature material, by mass fraction, includes: Si: 0.24% - 4.8%, Mg: 0.597% - 0.697%, RE: 6% - 9.8%, and the balance is Al and inevitable impurities; wherein, RE is a rare earth element. The microstructure of the aluminum alloy armature material includes: a skeleton phase distributed in a network-like skeleton in the aluminum matrix and a wear-resistant phase dispersed in the aluminum matrix. The skeleton phase includes an Al-RE compound phase, and the wear-resistant phase includes an Mg2Si phase.

[0006] In the above implementation process, by controlling each chemical component, a skeleton phase of Al-RE compound and a wear-resistant phase of Mg2Si are formed in the aluminum matrix. The skeleton phase of Al-RE compound has good strength performance and wear resistance, and the wear-resistant phase of Mg2Si has good wear resistance and electrical conductivity, making the aluminum alloy armature material have the characteristics of low density, high specific strength, good wear resistance, good electrical conductivity, and excellent room-temperature mechanical properties.

[0007] As an alternative embodiment, the chemical composition of the aluminum alloy armature material, by mass fraction, includes: Si: 0.4% - 1.0%, Mg: 0.620% - 0.670%, RE: 9.2% - 9.6%, and the balance is Al and inevitable impurities.

[0008] As an alternative embodiment, the rare earth element includes Ce and / or La.

[0009] As an alternative embodiment, the compound in the Al-RE compound phase includes Al x RE y and / or Al a RE b Si c , where x, y, a, b, and c are each independently selected from any positive integer.

[0010] As an alternative embodiment, the relative density of the aluminum alloy armature material is greater than 99%; and / or

[0011] The density of the aluminum alloy armature material is 2.75 - 2.82 g / cm 3 ; and / or

[0012] The properties of the aluminum alloy armature material at room temperature satisfy: tensile strength of 470 - 530 MPa, yield strength of 350 - 430 MPa, elongation of 6.5% - 12.0%, electrical conductivity of 33% IACS - 40% IACS, and wear rate of 3.3×10 -4 - 7.0×10 -4 mm 3 / (N·min).

[0013] In a second aspect, an embodiment of the present application provides a method for preparing an aluminum alloy armature material, where the aluminum alloy armature material is the aluminum alloy armature material described in the first aspect, and the method includes:

[0014] Mix the first alloy powder and the second alloy powder to obtain a mixed powder. The chemical composition of the first alloy powder includes Al, RE, Mg, and inevitable impurities, and the chemical composition of the second alloy powder includes Al, Si, Mg, and inevitable impurities;

[0015] Use selective laser to melt and solidify the mixed powder to form a skeleton phase distributed in a reticular skeleton in the aluminum matrix, obtaining an intermediate product;

[0016] Perform heat treatment on the intermediate product to form wear-resistant phases dispersed in the aluminum matrix, obtaining the aluminum alloy armature material.

[0017] In the above implementation process, additive manufacturing technology is combined with heat treatment. By additive manufacturing, one or more three-dimensional skeletons of Al-RE compounds are obtained to improve the strength and wear resistance of the alloy. By heat treatment, Mg2Si is precipitated to improve the wear resistance and conductivity of the aluminum matrix. The obtained aluminum alloy armature material has the characteristics of low density, high specific strength, good wear resistance, good conductivity, and excellent room temperature mechanical properties.

[0018] As an optional implementation manner, the volume particle size distribution of the first alloy powder is 10 - 75 μm; and / or

[0019] The volume particle size distribution of the second alloy powder is 15 - 53 μm; and / or

[0020] Both the first alloy powder and the second alloy powder are spherical. Preferably, the sphericity of both the first alloy powder and the second alloy powder is greater than 95%; and / or

[0021] The mass ratio of the first alloy powder to the second alloy powder is (60 - 98):(2 - 40); and / or

[0022] The mixing method of the first alloy powder and the second alloy powder is ball milling mixing. The rotation speed of the ball milling mixing is 100 - 300 rpm, the time of the ball milling mixing is 5 - 15 h, and the ball-to-material ratio of the ball milling mixing is (2 - 6):1.

[0023] In the process of melting and solidifying a mixed powder using selective laser, the powder particles are first spread into a powder layer under the action of a powder spreading mechanism. The size of the powder particles will affect the thickness of the powder layer. The smaller the powder particle size, the larger the specific surface area, and the sintering driving force increases. Generally, the powder particle size for selective laser melting and solidification forming is 30 - 50 μm. In this embodiment, the volume particle size distribution of the first alloy powder is controlled to be 10 - 75 μm, and the volume particle size distribution of the second alloy powder is 15 - 53 μm. Compared with the general situation, powders with smaller and larger volume particle sizes are added. The gaps between finer powder particles are small, and the connection between adjacent powder layers is tight, which is beneficial to improving the density and strength of the printed alloy. At the same time, adding some powders with larger particle sizes and using them in proportion with fine powders, the fine particles fill the gaps in the large particles, improving the packing density of the powder, as well as the strength and surface quality of the printed formed alloy. At the same time, good fluidity of the powder is crucial for obtaining a uniform and flat powder layer. Generally speaking, spherical or near-spherical powders have good fluidity, are not easily blocked in the powder supply system during the printing process, can be spread into thin layers, thereby improving the dimensional accuracy, surface quality, as well as the density and tissue uniformity of the alloy formed by selective laser melting, and further improving the quality of the alloy. Therefore, controlling the sphericity of the first alloy powder and the second alloy powder to be greater than 95% can improve the quality of the product.

[0024] As an alternative embodiment, the process parameters of the selective laser include: laser power of 150 - 300 W, scanning layer thickness of 10 - 30 μm, spot diameter of 70 - 100 μm, scanning pitch of 90 - 130 μm, and scanning speed of 400 - 1200 mm / s.

[0025] In the above implementation process, by controlling the parameters related to laser, scanning, powder, and temperature, it is suitable for the processing of aluminum alloy powder, can avoid the generation of large thermal stress inside the product, thereby avoiding the occurrence of warping, cracking and other adverse phenomena, and at the same time can also avoid the generation of defects such as pores and balling.

[0026] As an alternative embodiment, the temperature of the heat treatment is 150 - 175 °C; and / or

[0027] The time of the heat treatment is 5 - 10 h.

[0028] Control the temperature and time of the heat treatment so that Mg2Si can be completely and fully precipitated, while avoiding excessive coarsening and uneven distribution of Mg2Si.

[0029] In the third aspect, the embodiments of the present application provide an electromagnetic gun, and the armature material of the electromagnetic gun is the aluminum alloy armature material described in the first aspect or the material prepared by the preparation method of the aluminum alloy armature material described in the second aspect.

[0030] Since the armature materials provided above have good mechanical properties, strength properties, and wear resistance properties, they can be preferably applied to the preparation materials of electromagnetic guns to meet the actual combat requirements of electromagnetic guns. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings herein are incorporated into and constitute a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0033] Figure 1 It is a transmission electron microscope image of the aluminum alloy armature material provided in Embodiment 1 of the present application;

[0034] Figure 2 It is a transmission electron microscope image of the aluminum alloy armature material provided in Comparative Example 2 of the present application;

[0035] Figure 3 It is a transmission electron microscope image of the aluminum alloy armature material provided in Comparative Example 4 of the present application;

[0036] Figure 4 It is a transmission electron microscope image of the aluminum alloy armature material provided in Comparative Example 6 of the present application;

[0037] Figure 5 It is a flowchart of the method provided in the embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0039] Unless otherwise specifically stated, all kinds of raw materials, reagents, instruments, and equipment used in the present application can be obtained through the market or can be prepared by existing methods.

[0040] Various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present application; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0041] In the present application, unless otherwise stated, the orientation terms such as "upper" and "lower" specifically refer to the drawing direction in the drawings. Additionally, in the description of the specification of the present application, the terms "comprising", "including", etc. mean "including but not limited to". In this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this text, "and / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Where A and B can be singular or plural. In this text, "at least one" means one or more, and "a plurality" means two or more. "At least one kind", "at least one of the following (items)", or similar expressions refer to any combination of these items, including any combination of single (item) or plural items. For example, "at least one of a, b, or c", or, "at least one of a, b, and c" can all represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0042] An aluminum alloy armature material is provided in an embodiment of the present application. The chemical composition of the aluminum alloy armature material by mass fraction includes: Si: 0.24% - 4.8%, Mg: 0.597% - 0.697%, RE: 6% - 9.8%, and the rest are Al and inevitable impurities; wherein, RE is a rare earth element. The microstructure of the aluminum alloy armature material includes: a skeleton phase distributed in a network skeleton in the aluminum matrix and a wear-resistant phase dispersed in the aluminum matrix. The skeleton phase includes an Al-RE compound phase, and the wear-resistant phase includes an Mg2Si phase.

[0043] On the one hand, Si forms Al with other elements such as Al and RE a RE b Sic On one hand, it can improve the strength of the alloy. On the other hand, it can precipitate Mg elements in the form of Mg2Si, while improving the wear resistance and electrical conductivity of the alloy. Controlling the mass content of Si to be 0.24%-4.8% can precipitate all Mg in the aluminum matrix as much as possible, which is beneficial to the wear resistance of the alloy; at the same time, it is beneficial to the electrical conductivity of the alloy.

[0044] The function of Mg is that on one hand, it can reduce the viscosity of the melt of the first alloy during the powder making stage, improve the fluidity, so as to obtain rare earth aluminum alloy powder with high sphericity, better meeting the use requirements of additive manufacturing. On the other hand, it reacts with Si to precipitate hard Mg2Si phase during heat treatment, improving the wear resistance of the alloy. Controlling the mass content of Mg to be 0.597%-0.697% can precipitate an appropriate amount of Mg2Si phase after heat treatment, which is beneficial to the wear resistance of the alloy; at the same time, it can control the concentration of solute atoms in the aluminum matrix, which is beneficial to the electrical conductivity of the alloy, and further enables the alloy to meet the requirements of the electrical conductivity of the armature material for electromagnetic railguns.

[0045] The function of RE is to form a three-dimensional network RE-containing skeleton in the aluminum matrix, and this skeleton is the main strengthening phase of the rare earth aluminum alloy armature material. The binary Al-RE alloy has a narrow solidification temperature range near the eutectic composition (Al-(10-12)wt% RE), which is beneficial to improving the printability of the alloy. Controlling the mass content of RE to be 6%-9.8% can avoid the alloy composition becoming hypereutectic and precipitating the Al x RE y phase, which is beneficial to the plasticity of the alloy; making the content of the Al x RE y phase and the Al a RE b Si c phase relatively large, which is beneficial to the strengthening effect of the alloy. RE can be specifically selected from Ce and / or La.

[0046] In some embodiments, the chemical composition of the aluminum alloy armature material in mass fraction includes: Si: 0.4%-1.0%, Mg: 0.620%-0.670%, RE: 9.2%-9.6%, and the rest is Al and inevitable impurities.

[0047] In some embodiments, the compounds in the Al-RE compound phase include Al x RE y and / or Al a RE b Si c , where x, y, a, b, and c are each independently selected from any positive integer.

[0048] In some embodiments, the density of the aluminum alloy armature material is greater than 99%; the density of the aluminum alloy armature material is 2.75 - 2.82 g / cm 3 ; the properties of the aluminum alloy armature material at room temperature meet the following requirements: the tensile strength is 470 - 530 MPa, the yield strength is 350 - 430 MPa, the elongation is 6.5% - 12.0%, the conductivity is 33% IACS - 40% IACS, and the wear rate is 3.3×10 -4 ~7.0×10 -4 mm 3 / (N·min).

[0049] By controlling the chemical components, a framework phase of Al-RE compounds and a wear-resistant phase of Mg2Si are formed in the aluminum matrix of the aluminum alloy armature material. The framework phase of Al-RE compounds has good strength and wear resistance, and the wear-resistant phase of Mg2Si has good wear resistance and electrical conductivity, making the aluminum alloy armature material have the characteristics of low density, high specific strength, good wear resistance, good electrical conductivity, and excellent mechanical properties at room temperature.

[0050] Aluminum alloy itself has low density and high specific strength. Selective laser melting of rare earth aluminum alloy has fine grains and combines multiple strengthening mechanisms, making the alloy have excellent mechanical properties. The solubility of rare earth elements in the aluminum matrix is extremely low, and after heat treatment, Mg and Si elements precipitate from the aluminum matrix, increasing the electrical conductivity of the alloy. The precipitated Mg2Si has advantages such as low density and high hardness, further improving the wear resistance of the alloy. The above characteristics endow the obtained aluminum alloy armature material with comprehensive properties of low density, high specific strength, good wear resistance and electrical conductivity, and excellent mechanical properties at room temperature.

[0051] Based on the same inventive concept, an embodiment of the present application also provides a preparation method of an aluminum alloy armature material. The aluminum alloy armature material is the aluminum alloy armature material provided above. The method includes:

[0052] S1. Mix the first alloy powder and the second alloy powder to obtain a mixed powder. The chemical components of the first alloy powder include: Al, RE, Mg, and inevitable impurities. The chemical components of the second alloy powder include Al, Si, Mg, and inevitable impurities.

[0053] Specifically, the first alloy powder can be selected from rare earth aluminum alloy powders. The weight percentages of the components of the rare earth aluminum alloy powders are as follows: RE is 8.00 - 10.00%, Mg is 0.5 - 1.0%, the content of other impurities is less than 0.10%, and the rest is aluminum. Optionally, the weight percentages of the components of the rare earth aluminum alloy powders are: RE is 10.00%, Mg is 0.65%, the content of other impurities is less than 0.10%, and the rest is aluminum. The second alloy powder can be selected from Al-Si-Mg alloy powders. The weight percentages of the components of the Al-Si-Mg alloy powders are as follows: Si is 10 - 12%, Mg is 0.6 - 1.0%, the content of other impurities is less than 0.10%, and the rest is aluminum. Optionally, the weight percentages of the components of the Al-Si-Mg alloy powders are: Si is 12.02%, Mg is 0.6%, the content of other impurities is less than 0.10%, and the rest is aluminum. The inventors found that when the components and their proportions in the first alloy powder and the second alloy powder are controlled within the above ranges, the first alloy powder and the second alloy powder can have better sphericity, and thus better fluidity, which is convenient for subsequent composition control of the finally formed aluminum alloy material through the powder mass ratio.

[0054] In some embodiments, the volume particle size distribution of the first alloy powder is 10 - 75 μm; the volume particle size distribution of the second alloy powder is 15 - 53 μm; in the process of using selective laser to melt and solidify the mixed powder for forming, the powder particles are first spread into a powder layer under the action of the powder spreading mechanism. The size of the powder particle size will affect the thickness of the powder spreading layer. The smaller the powder particle size, the larger the specific surface area, and the sintering driving force increases. Generally, the powder particle size for selective laser melting and solidification forming is 30 - 50 μm. In this embodiment, the volume particle size distribution of the first alloy powder is controlled to be 10 - 75 μm, and the volume particle size distribution of the second alloy powder is 15 - 53 μm. Compared with the general situation, powders with smaller and larger volume particle sizes are also added. The gaps between the finer powder particles are small, and the connection between adjacent two powder spreading layers is tight, which is beneficial to improving the density and strength of the printed alloy. At the same time, adding some powders with larger particle sizes and using them in proportion with the fine powders, the fine particles fill the gaps in the large particles, improving the packing density of the powder, as well as the strength and surface quality of the printed and formed alloy.

[0055] In some embodiments, both the first alloy powder and the second alloy powder are spherical. Preferably, the sphericity of the first alloy powder and the second alloy powder is greater than 95%. Good fluidity of the powder is crucial for obtaining a uniform and flat powder layer. Generally speaking, spherical or near-spherical powders have good fluidity and are not easily blocked in the powder feeding system during printing, can be spread into a thin layer, thereby improving the dimensional accuracy, surface quality, density and tissue uniformity of the selective laser melting formed alloy, and further improving the quality of the alloy. Therefore, controlling the sphericity of the first alloy powder and the second alloy powder to be greater than 95% can improve the quality of the product.

[0056] In some embodiments, the mass ratio of the first alloy powder to the second alloy powder is (60 - 98):(2 - 40). By controlling the dosages of the first alloy powder and the second alloy powder, the element content in the printed aluminum alloy armature material can be controlled, and then the structure and properties of the armature material can be controlled. It can enable the alloy to generate sufficient Mg2Si to achieve the expected wear resistance, and at the same time can control the solid solution elements in the aluminum matrix to ensure the conductivity of the alloy. In addition, it can also ensure the generation of sufficient skeleton phases to ensure the strength performance of the alloy.

[0057] In some embodiments, the mixing method of the first alloy powder and the second alloy powder is ball milling. The rotation speed of the ball milling is 100 - 300 rpm, the time of the ball milling is 5 - 15 h, and the ball-to-material ratio of the ball milling is (2 - 6):1.

[0058] S2. Use selective laser to melt and solidify the mixed powder to form a skeleton phase distributed in a network structure in the aluminum matrix, and obtain an intermediate product;

[0059] In some embodiments, the process parameters of the selective laser include: laser power of 150 - 300 W, scanning layer thickness of 10 - 30 μm, spot diameter of 70 - 100 μm, scanning spacing of 90 - 130 μm, and scanning speed of 400 - 1200 mm / s. By controlling the parameters related to laser, scanning, powder and temperature, it is suitable for the processing of aluminum alloy powder, can avoid the generation of large thermal stress inside the product, and thus avoid causing warping, cracking and other defects in the product. At the same time, it can also avoid the generation of defects such as pores and balling.

[0060] S3. Heat-treat the intermediate product to form wear-resistant phases dispersed in the aluminum matrix, and obtain the aluminum alloy armature material.

[0061] In some embodiments, the heat treatment temperature is 150 - 175 °C, and the heat treatment time is 5 - 10 h. Controlling the heat treatment temperature and time within the above ranges can ensure that Mg2Si is completely and fully precipitated, and at the same time can avoid excessive coarsening and uneven distribution of Mg2Si.

[0062] This method uses ball milling to mix rare earth aluminum alloy powder and Al-Si-Mg alloy powder. By changing the ratio of the above two powders, the alloy composition of the final material can be changed, and the composition regulation of the material is simple and efficient. By adjusting the process parameters of conventional heat treatment, the mechanical properties and electrical conductivity of the material can be adjusted. The additive manufacturing technology is combined with heat treatment. Through additive manufacturing, a three-dimensional skeleton of one or more Al-RE compounds is obtained to improve the alloy strength and wear resistance. Through heat treatment, Mg2Si is precipitated to improve the wear resistance and electrical conductivity of the aluminum matrix. The obtained aluminum alloy armature material has the characteristics of low density, high specific strength, good wear resistance, good electrical conductivity, and excellent mechanical properties at room temperature.

[0063] Based on the same inventive concept, the embodiment of the present application also provides an electromagnetic gun, and the armature material of the electromagnetic gun is the aluminum alloy armature material provided above or the material prepared by the preparation method of the aluminum alloy armature material provided above. Since the armature material provided above has good mechanical properties, strength properties and wear resistance, it can be preferably applied to the preparation material of the electromagnetic gun to meet the actual combat requirements of the electromagnetic gun.

[0064] The following further elaborates the present application in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. The experimental methods without specific conditions noted in the following embodiments are usually determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0065] Example 1

[0066] This embodiment provides a preparation method of a high-strength and wear-resistant rare earth aluminum alloy armature material, including: performing according to the following steps:

[0067] S1, ball milling and mixing rare earth aluminum alloy powder and Al-Si-Mg alloy powder. After ball milling and mixing, a uniform mixed powder is obtained. The Al-Si-Mg alloy powder is evenly distributed in the Al-RE (RE = Ce, La) powder. The composition of the rare earth aluminum alloy powder is RE 10.00%, Mg 0.6%, and the content of other impurities is less than 0.10%, and the rest is aluminum. The particle size distribution of the rare earth aluminum alloy powder is 20-65 μm, the average particle size is 46 μm, and the powder sphericity is greater than 98%. The composition of the Al-Si-Mg alloy powder is Si 12.02%, Mg 0.7%, and the content of other impurities is less than 0.10%, and the rest is aluminum. The particle size of the Al-Si-Mg alloy powder is 15-53 μm, and the powder sphericity is greater than 95%. In the mixed powder, the mass percentage of the rare earth aluminum alloy powder is 96%, and the mass percentage of the Al-Si-Mg alloy powder is 4%.

[0068] S2. Using the selective laser melting technology, the mixed powder is rapidly solidified and formed into a printed alloy to obtain an aluminum alloy in which nano-scale Al-RE (RE = Ce, La) intermetallic compounds are distributed in a three-dimensional network skeleton in the matrix; wherein, the selective laser melting forming method adopts the following printing parameters: the laser power is 200 W, the scanning layer thickness is 30 μm, the spot diameter is 70 μm, the scanning spacing is 130 μm, and the scanning speed is 1000 mm / s.

[0069] S3. The rapidly solidified and formed aluminum alloy is subjected to low-temperature heat treatment at a heat treatment temperature of 175 °C for a heat treatment time of 5 h, and the high-strength and wear-resistant rare-earth aluminum alloy armature material is obtained.

[0070] It is detected that the density of the obtained high-strength and wear-resistant rare-earth aluminum alloy armature material is greater than 99.8%, and the density is 2.82 g / cm 3 . Through testing, its tensile strength at room temperature is 520 MPa, the yield strength is 409 MPa, the elongation is 4.2%, the conductivity is 38% IACS, and the wear rate is 5.0×10 -4 mm 3 / (N·min).

[0071] Example 2

[0072] For the selective laser melting forming method of the armature material prepared in this example, the following printing parameters are adopted: the laser power is 250 W, the scanning layer thickness is 30 μm, the spot diameter is 70 μm, the scanning spacing is 100 μm, and the scanning speed is 1200 mm / s. The rest is the same as in Example 1.

[0073] It is detected that the density of the obtained high-strength and wear-resistant rare-earth aluminum alloy armature material is greater than 99.8%, and the density is 2.83 g / cm 3 . Through testing, its tensile strength at room temperature is 495 MPa, the yield strength is 375 MPa, the elongation is 4.3%, the conductivity is 35.7% IACS, and the wear rate is 4.6×10 -4 mm 3 / (N·min).

[0074] Example 3

[0075] In the armature material prepared in this example, the mass percentage of the rare-earth aluminum alloy powder is 90%, and the mass percentage of the Al-Si-Mg alloy powder is 10%. The rest of the steps are the same as in Example 1.

[0076] It is detected that the density of the obtained high-strength and wear-resistant rare-earth aluminum alloy armature material is greater than 99.8%, and the density is 2.82 g / cm 3After testing, its tensile strength at room temperature is 475 MPa, yield strength is 372 MPa, elongation is 6.5%, electrical conductivity is 32% IACS, and wear rate is 3.4×10 -4 mm 3 / (N·min).

[0077] Example 4

[0078] In the armature material prepared in this example, the mass percentage of rare earth aluminum alloy powder is 95%, and the mass percentage of Al-Si-Mg alloy powder is 5%. The remaining steps are the same as those in Example 1.

[0079] After detection: the density of the obtained high-strength wear-resistant rare earth aluminum alloy armature material is greater than 99.8%, and the density is 2.83 g / cm 3 After testing, its tensile strength at room temperature is 503 MPa, yield strength is 389 MPa, elongation is 3.8%, electrical conductivity is 36% IACS, and wear rate is 4.2×10 -4 mm 3 / (N·min).

[0080] Example 5

[0081] The heat treatment process parameters of the armature material prepared in this example are aging temperature of 155 °C and aging time of 10 h. The remaining steps are the same as those in Example 1.

[0082] After detection: the density of the obtained high-strength wear-resistant rare earth aluminum alloy armature material is greater than 99.7%, and the density is 2.82 g / cm 3 After testing, its tensile strength at room temperature is 482 MPa, yield strength is 365 MPa, elongation is 7.3%, electrical conductivity is 35% IACS, and wear rate is 3.8×10 -4 mm 3 / (N·min).

[0083] Example 6

[0084] The heat treatment process parameters of the armature material prepared in this example are aging temperature of 165 °C and aging time of 7 h. The remaining steps are the same as those in Example 1.

[0085] After detection: the density of the obtained high-strength wear-resistant rare earth aluminum alloy armature material is greater than 99.8%, and the density is 2.80 g / cm 3 After testing, its tensile strength at room temperature is 529 MPa, yield strength is 398 MPa, elongation is 4.0%, electrical conductivity is 34% IACS, and wear rate is 5.6×10 -4 mm 3 / (N·min).

[0086] Comparative Example 1

[0087] Other preparation conditions are exactly the same as those in Example 1, except that the printed and formed aluminum alloy is not heat-treated.

[0088] After testing, the density of the obtained aluminum alloy material is greater than 99.5%, and the density is 2.79 g / cm 3 . After testing, its tensile strength at room temperature is 480 MPa, yield strength is 361 MPa, elongation is 3.9%, electrical conductivity is 30% IACS, and wear rate is 6.8×10 -4 mm 3 / (N·min).

[0089] Comparative Example 2

[0090] Other preparation conditions are exactly the same as those in Example 1, except that the powder used for selective laser melting is 100% of the selected rare earth aluminum alloy powder, that is, the obtained aluminum alloy material does not contain element Si.

[0091] After testing, the density of the obtained aluminum alloy material is greater than 99.9%, and the density is 2.83 g / cm 3 . After testing, its tensile strength at room temperature is 455 MPa, yield strength is 326 MPa, elongation is 10.0%, electrical conductivity is 32% IACS, and wear rate is 8.0×10 -4 mm 3 / (N·min).

[0092] Comparative Example 3

[0093] Other preparation conditions are the same as those in Example 1, except that the aging parameters for low-temperature heat treatment of the printed and formed aluminum alloy are: aging temperature is 175 °C, and aging time is 3 h.

[0094] After testing, the density of the obtained aluminum alloy material is greater than 99.2%, and the density is 2.79 g / cm 3 . After testing, its tensile strength at room temperature is 492 MPa, yield strength is 350 MPa, elongation is 5.7%, electrical conductivity is 31% IACS, and wear rate is 7.1×10 -4 mm 3 / (N·min).

[0095] Comparative Example 4

[0096] Other preparation conditions are the same as those in Example 1, except that the aging parameters for low-temperature heat treatment of the printed and formed aluminum alloy are: aging temperature is 120 °C, and aging time is 5 h.

[0097] After testing, the density of the obtained aluminum alloy material is greater than 99.8%, and the density is 2.81 g / cm3 After testing, its tensile strength at room temperature is 462 MPa, yield strength is 318 MPa, elongation is 4.8%, electrical conductivity is 31.2% IACS, and wear rate is 6.9×10 -4 mm 3 / (N·min).

[0098] Comparative Example 5

[0099] Other preparation conditions are the same as those in Example 1, except that the selective laser melting forming method uses the following printing parameters: laser power is 200 W, scanning layer thickness is 30 μm, spot diameter is 70 μm, scanning spacing is 130 μm, and scanning speed is 300 mm / s.

[0100] After testing, the density of the obtained aluminum alloy material is greater than 98%, and the density is 2.76 g / cm 3 After testing, its tensile strength at room temperature is 450 MPa, yield strength is 322 MPa, elongation is 3.8%, electrical conductivity is 30% IACS, and wear rate is 7.5×10 -4 mm 3 / (N·min).

[0101] Comparative Example 6

[0102] Other preparation conditions are the same as those in Example 1, except that the selective laser melting forming method uses the following printing parameters: laser power is 200 W, scanning layer thickness is 30 μm, spot diameter is 70 μm, scanning spacing is 130 μm, and scanning speed is 1500 mm / s.

[0103] After testing, the density of the obtained aluminum alloy material is greater than 97%, and the density is 2.70 / cm 3 After testing, its tensile strength at room temperature is 432 MPa, yield strength is 319 MPa, elongation is 3.9%, electrical conductivity is 30.2% IACS, and wear rate is 7.9×10 -4 mm 3 / (N·min).

[0104] Performance tests were carried out on the aluminum alloy armature materials provided in Examples 1 to 6 and Examples 1 to 6, and the results are shown in the following table:

[0105]

[0106] As can be seen from the above table, the aluminum alloy armature material obtained by using the method provided in the embodiment of the present application has the characteristics of low density, high specific strength, good wear resistance, good electrical conductivity, and excellent mechanical properties at room temperature. By comparing Comparative Examples 1, 2, 3, and 4 with Example 1, it can be obtained that the aluminum alloy materials without Mg2Si precipitation or incomplete Mg2Si precipitation have lower strength, electrical conductivity, and wear resistance. The inventor analyzed that the reasons may be the lack of precipitation strengthening of Mg2Si; the high content of solid solution elements in the aluminum matrix, resulting in a decrease in electrical conductivity; and the absence of uniformly distributed hard phase Mg2Si, resulting in a decrease in wear resistance. The above shows that the difference in the distribution state of alloy elements leads to the change of the properties of aluminum alloy materials. In addition, by comparing Comparative Examples 5 and 6 with Example 1, it can be seen that the parameter selection area of selective laser melting printing forming has an important influence on the properties of aluminum alloy. For example, too fast or too slow scanning speed will lead to an increase in defects and a decrease in properties in the printed forming alloy.

[0107] The above are only specific embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A preparation method of an aluminum alloy armature material, characterized in that The method includes: Mixing a first alloy powder and a second alloy powder to obtain a mixed powder. The chemical composition of the first alloy powder includes Al, RE, Mg, and inevitable impurities. The chemical composition of the second alloy powder includes Al, Si, Mg, and inevitable impurities; Using selective laser to melt and solidify the mixed powder to form a skeleton phase distributed in a reticular skeleton in the aluminum matrix, obtaining an intermediate product; Performing heat treatment on the intermediate product to form wear-resistant phases dispersed in the aluminum matrix, obtaining an aluminum alloy armature material; the temperature of the heat treatment is 150 - 175°C, and the time of the heat treatment is 5 - 10 h; The chemical composition of the aluminum alloy armature material in terms of mass fraction includes: Si: 0.24% - 4.8%, Mg: 0.597% - 0.697%, RE: 6% - 9.8%, and the rest is Al and inevitable impurities; wherein, RE is a rare earth element. The microstructure of the aluminum alloy armature material includes: a skeleton phase distributed in a reticular skeleton in the aluminum matrix and wear-resistant phases dispersed in the aluminum matrix. The skeleton phase includes an Al-RE compound phase, and the wear-resistant phase includes an Mg2Si phase; The process parameters of the selective laser include: laser power of 150 - 300 W, scanning layer thickness of 10 - 30 μm, spot diameter of 70 - 100 μm, scanning pitch of 90 - 130 μm, and scanning speed of 400 - 1200 mm / s.

2. The preparation method of the aluminum alloy armature material according to claim 1, characterized in that, The chemical composition of the aluminum alloy armature material in terms of mass fraction includes: Si: 0.4% - 1.0%, Mg: 0.620% - 0.670%, RE: 9.2% - 9.6%, and the rest is Al and inevitable impurities.

3. The preparation method of the aluminum alloy armature material according to claim 1, characterized in that, The rare earth element includes Ce and / or La.

4. The preparation method of the aluminum alloy armature material according to claim 1, characterized in that, The compounds in the Al-RE compound phase include Al x RE y and / or Al a RE b Si c , where x, y, a, b, and c are each independently selected from any positive integer.

5. The preparation method of the aluminum alloy armature material according to claim 1, characterized in that, The density of the aluminum alloy armature material is greater than 99%; and / or The density of the aluminum alloy armature material is 2.75~2.82 g / cm 3 ; and / or The properties of the aluminum alloy armature material at room temperature meet the following requirements: the tensile strength is 470 - 530 MPa, the yield strength is 350 - 430 MPa, the elongation is 6.5% - 12.0%, the conductivity is 33% IACS - 40% IACS, and the wear rate is 3.3×10 -4 ~7.0×10 - 4 mm 3 / (N·min).

6. The preparation method of the aluminum alloy armature material according to claim 1, characterized in that, The volume particle size distribution of the first alloy powder is 10 - 75 μm; and / or The volume particle size distribution of the second alloy powder is 15 - 53 μm; and / or Both the first alloy powder and the second alloy powder are spherical, and the sphericity of both the first alloy powder and the second alloy powder is greater than 95%; and / or The mass ratio of the first alloy powder to the second alloy powder is (60 - 98):(2 - 40); and / or The mixing method of the first alloy powder and the second alloy powder is ball milling mixing. The rotation speed of the ball milling mixing is 100 - 300 rpm, the time of the ball milling mixing is 5 - 15 h, and the ball-to-material ratio of the ball milling mixing is (2 - 6):

1.

7. An electromagnetic gun, characterized in that, The armature material of the electromagnetic gun is a material prepared by the preparation method of the aluminum alloy armature material according to any one of claims 1 to 6.

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