A particle-reinforced 7xxx aluminum alloy welding wire, and methods of making and using the same

Abstract

The present application relates to the technical field of aluminum alloy welding wire, in particular to a kind of particle reinforced 7XXX aluminum alloy welding wire and its preparation method and application.Particle reinforced 7XXX aluminum alloy welding wire is mainly made of Al-Zn-Mg-Cu alloy powder and reinforcing particles;Among them, the volume of reinforcing particles accounts for 5% to 25% of the sum of the volume of Al-Zn-Mg-Cu alloy powder and reinforcing particles.The particle reinforced 7XXX aluminum alloy welding wire can be used as both welding material for aluminum matrix composites and additive material for manufacturing large and complex structural components through arc additive technology.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy welding wire technology, and more specifically, to a particle-reinforced 7XXX aluminum alloy welding wire, its preparation method, and its application. Background Technology

[0002] Aluminum alloys, with their low density, high specific strength, high fracture toughness, and good formability, are widely used in transportation, construction, furniture, aerospace, and many other fields. Among them, the 7XXX series Al-Zn-Mg-Cu alloys, as ultra-hard aluminum alloys, have become a hot topic in lightweight, high-strength structural materials due to their high strength and low density. For example, in the 1960s and 70s, 7075 aluminum alloy was used as a support material for electronic equipment in aircraft.

[0003] However, with the rapid development of composite materials, particle-reinforced aluminum matrix composites have become a typical material to replace traditional aluminum alloys due to their superior performance. For example, SiC / 6092 aluminum matrix composites, which replaced the original 2XXX aluminum alloys, have a stiffness 1.5 times that of the original materials and a service life more than 20 times longer. The large-scale application of aluminum matrix composites inevitably involves the material joining process, and the high strength characteristics of aluminum matrix composites determine that traditional 5356 aluminum alloy welding wire, 6061 aluminum alloy welding wire, and even 7075 aluminum alloy welding wire cannot meet the strength requirements of the materials.

[0004] Particle-reinforced aluminum matrix composites possess the low-density characteristics of aluminum alloys, while the mechanical properties, especially strength, are significantly improved due to particle reinforcement.

[0005] For example, patent CN108823448A uses 3%-5% SiC powder and TiO2 sol to mix and calcine to generate TiC and SiO2. This is then mixed with molten aluminum alloy and cast to obtain a SiC particle-reinforced aluminum matrix composite material. TiC and SiO2 act as a transition layer to improve the interfacial bonding between SiC and molten aluminum, and to improve the dispersibility of SiC particles in the molten aluminum, thereby increasing the strength of the composite material. However, this patent uses a stirred casting method. Due to the difference in properties between the particle reinforcement and the molten aluminum, there is an upper limit to the reinforcement content (generally no more than 5% by mass). The reinforced molten aluminum has poor fluidity, making it difficult to cast into complex structural parts.

[0006] For example, patent CN105714137A uses powder metallurgy technology to obtain aluminum-based composite materials with excellent comprehensive properties such as large size, thin walls, and high elastic modulus through processes such as drying, powder mixing, cold isostatic pressing, hot isostatic pressing sintering, and blank removal. This patent uses powder metallurgy to prepare thin-walled plates, and although the content of reinforcing phase can achieve the required high proportion, the manufacturing cost is high due to the use of complex processes such as cold isostatic pressing and hot isostatic pressing.

[0007] Furthermore, the oxygen content and impurity elements of aluminum-based composite materials prepared by powder sintering are difficult to control, making them unsuitable as welding materials for secondary remelting. They are prone to defects and reduce the mechanical properties of the weld.

[0008] In view of this, the present invention is hereby proposed. Summary of the Invention

[0009] The primary objective of this invention is to provide a particle-reinforced 7XXX aluminum alloy welding wire, wherein the volume percentage of reinforcing particles is not less than 5%. This particle-reinforced 7XXX aluminum alloy welding wire can be used both as a welding material for aluminum-based composite materials and as an additive manufacturing material for large and complex structural components via arc additive manufacturing technology. This solves the problems of uneven distribution of reinforcing particles and difficulty in casting complex structural components in existing aluminum alloy welding wires using the stir casting method.

[0010] The second objective of this invention is to provide a method for preparing particle-reinforced 7XXX aluminum alloy welding wire.

[0011] A third objective of this invention is to provide the application of the aforementioned particle-reinforced 7XXX aluminum alloy welding wire in welding and arc additive manufacturing.

[0012] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0013] This invention provides a particle-reinforced 7XXX aluminum alloy welding wire, which is mainly made of Al-Zn-Mg-Cu alloy powder and reinforcing particles;

[0014] The volume of the reinforcing particles accounts for 5% to 25% of the sum of the volumes of the Al-Zn-Mg-Cu alloy powder and the reinforcing particles.

[0015] This invention further provides a method for preparing the aforementioned particle-reinforced 7XXX aluminum alloy welding wire, comprising the following steps:

[0016] After the mixture containing Al-Zn-Mg-Cu alloy powder and reinforcing particles is loaded into an aluminum shell, it undergoes a first hot extrusion to obtain a bar stock;

[0017] After the bar stock is surface-machined, it undergoes a second hot extrusion, followed by a roll forming process to obtain a semi-finished product. The semi-finished product is then shaped by a die to obtain the particle-reinforced 7XXX aluminum alloy welding wire.

[0018] This invention also provides the application of the aforementioned particle-reinforced 7XXX aluminum alloy welding wire in welding and arc additive manufacturing.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] (1) The particle-reinforced 7XXX aluminum alloy welding wire provided by the present invention has a volume ratio of not less than 5% for the reinforcing particles. The welding wire can be used for welding reinforced aluminum alloy materials and for arc additive manufacturing of high-strength complex structural parts.

[0021] (2) The reinforcement particles in the 7XXX aluminum alloy welding wire prepared by the method of the present invention are uniformly distributed. During the additive manufacturing process, the reinforcement particles in the sample can also be uniformly distributed due to the genetic effect of the material, thereby improving the performance of the sample.

[0022] (3) The preparation method of particle-reinforced 7XXX aluminum alloy welding wire provided by the present invention improves the strength and hardness of the material after additive manufacturing. At the same time, additive manufacturing technology can be used to repair damaged parts, making maintenance simple and efficient, and significantly reducing costs.

[0023] (4) The preparation method of the particle-reinforced 7XXX aluminum alloy welding wire provided by the present invention uses a pure aluminum shell as a protective measure to form a smooth pure aluminum skin on the surface of the welding wire, which can reduce the surface roughness of the welding wire and thus improve the wire feeding performance. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a low-magnification macroscopic metallographic image of the cross-section of the particle-reinforced 7XXX aluminum alloy welding wire provided in Embodiment 4 of the present invention. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0027] In a first aspect, the present invention provides a particle-reinforced 7XXX aluminum alloy welding wire, which is mainly made of Al-Zn-Mg-Cu alloy powder and reinforcing particles.

[0028] The volume of the reinforcing particles accounts for 5% to 25% of the sum of the volumes of the Al-Zn-Mg-Cu alloy powder and the reinforcing particles. That is, the volume of the reinforcing particles is 5% to 25% of the total volume of the Al-Zn-Mg-Cu alloy powder and the reinforcing particles, including but not limited to any one of 5%, 7%, 9%, 10%, 12%, 15%, 18%, 20%, 22%, and 24%, or any range between two of them.

[0029] The particle-reinforced 7XXX aluminum alloy welding wire provided by this invention can be used for welding reinforced aluminum alloy materials, as well as for arc additive manufacturing of high-strength complex structural components.

[0030] This particle-reinforced 7XXX aluminum alloy welding wire can also be used as a repair material through additive manufacturing without replacing damaged structural components, resulting in low maintenance costs and simple, efficient operation.

[0031] Furthermore, the particle-reinforced 7XXX aluminum alloy welding wire provided by this invention does not have the limitation of less than 5% in the prior art, and can be artificially controlled according to requirements to meet personalized needs.

[0032] The particle-reinforced 7XXX aluminum alloy welding wire provided by this invention can also meet the strength and hardness requirements of the material.

[0033] In a preferred embodiment, the volume of the reinforcing particles accounts for 10% to 20% of the sum of the volumes of the Al-Zn-Mg-Cu alloy powder and the reinforcing particles, including but not limited to any one of 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, and 20%, or any range between the two.

[0034] In a preferred embodiment, the Al-Zn-Mg-Cu alloy powder comprises the following components by mass percentage: Zn 5.9%–8.8%, Mg 1.4%–3.1%, Cu 1.3%–2.2%, Cr ≤0.2%, with the balance being Al and other unavoidable impurities.

[0035] The Zn content, by mass percentage, includes, but is not limited to, any one of the following values ​​or a range between any two: 6.0%, 6.3%, 6.5%, 6.8%, 7.0%, 7.3%, 7.5%, 7.8%, 8.0%, 8.2%, and 8.5%. The Mg content, by mass percentage, includes, but is not limited to, any one of the following values ​​or a range between any two: 1.5%, 1.8%, 2.0%, 2.3%, 2.5%, 2.8%, and 3.0%. The Cu content, by mass percentage, includes, but is not limited to, any one of the following values ​​or a range between any two: 1.5%, 1.7%, 1.9%, 2.0%, and 2.1%. The Cr content, by mass percentage, includes, but is not limited to, any one of the following values ​​or a range between any two: 0.15%, 0.1%, 0.05%, and 0.01%.

[0036] Among them, Cr acts as a reinforcing phase in the alloy.

[0037] In one specific embodiment, the mass percentage content of each impurity element in the above Al-Zn-Mg-Cu alloy powder does not exceed 0.05%, and the sum of the mass percentages of each impurity element does not exceed 0.2%.

[0038] In one specific embodiment, the oxygen content in the Al-Zn-Mg-Cu alloy powder is less than 150 ppm.

[0039] It is understood that the above Al-Zn-Mg-Cu alloy powder can be prepared using any conventional alloy powder preparation method, such as mechanical physical method, ball milling method and atomization method, but not limited to these. The powder of the required particle size can be obtained by sieving.

[0040] In a preferred embodiment, the particle size of the Al-Zn-Cu-Mg alloy powder is 20 to 300 mesh, including but not limited to any one of 30 mesh, 50 mesh, 100 mesh, 150 mesh, 200 mesh, and 250 mesh, or a range between any two; more preferably, it is 150 to 220 mesh.

[0041] Among them, the particle size of Al-Zn-Cu-Mg alloy powder is controlled within the above range. Combined with the particle size of the reinforcing phase, a uniform mixing effect can be achieved, reducing the uneven mixing phenomenon caused by particle size issues. Furthermore, powders within this range are readily available and have low cost.

[0042] In a preferred embodiment, the reinforcing particles include at least one of SiC, Al2O3, and WC (tungsten carbide).

[0043] In a preferred embodiment, in order to ensure uniform mixing between the reinforcing particles and the alloy powder and to prevent the reinforcing particles from agglomerating, the particle size of the reinforcing particles is 150 to 400 mesh, including but not limited to the point value of any one of 200 mesh, 250 mesh, 300 mesh, and 350 mesh or the range between any two; more preferably, it is 280 to 320 mesh.

[0044] In a preferred embodiment, the particle-reinforced 7XXX aluminum alloy welding wire is mainly produced by powder metallurgy using the Al-Zn-Mg-Cu alloy powder and the reinforcing particles. Powder metallurgy refers to a process that uses metal powder as raw material and obtains a finished product through forming.

[0045] The use of powder metallurgy to prepare particle-reinforced 7XXX aluminum alloy welding wire can solve the problem of poor fluidity of the reinforced aluminum melt, which is difficult to cast into complex structural parts due to the difference in properties between the particle reinforcement and the aluminum melt in the stir casting method. Therefore, the use of powder metallurgy to prepare particle-reinforced 7XXX aluminum alloy welding wire can increase the reinforcement content, which can be set according to the required content.

[0046] In a preferred embodiment, the forming method of the powder metallurgy method includes hot extrusion.

[0047] Compared to cold isostatic pressing and hot isostatic pressing, hot extrusion has lower equipment requirements, requires less initial investment, and is simple and convenient to operate. Furthermore, hot extrusion has a short process flow, high efficiency, and can achieve continuous extrusion, enabling rapid mass production, making it more suitable for mass production.

[0048] More preferably, the hot extrusion is performed at least twice.

[0049] In a preferred embodiment, the powder metallurgy method specifically includes: mixing the Al-Zn-Mg-Cu alloy powder and the reinforcing particles, placing them in an aluminum shell, and then performing at least one hot extrusion.

[0050] It is understandable that the aluminum shell mentioned above refers to a metal aluminum shell, that is, a shell formed by pressing metal aluminum.

[0051] By placing a mixture of Al-Zn-Mg-Cu alloy powder and reinforcing particles inside an aluminum shell and then hot-extruded it, the problem of high surface roughness of reinforced welding wire can be solved and the wire feeding performance can be improved.

[0052] In one specific embodiment, the particle-reinforced 7XXX aluminum alloy welding wire includes shapes such as filaments, wires, and thin rods.

[0053] In one specific embodiment, the particle-reinforced 7XXX aluminum alloy welding wire includes a composite material and an aluminum cladding layer covering the outer surface of the composite material, wherein the composite material is mainly made of Al-Zn-Mg-Cu alloy powder and reinforcing particles.

[0054] Secondly, the present invention provides a method for preparing the aforementioned particle-reinforced 7XXX aluminum alloy welding wire, comprising the following steps:

[0055] Al-Zn-Mg-Cu alloy powder and reinforcing particles are mixed evenly to obtain a mixture. The mixture is then loaded into an aluminum shell and subjected to a first hot extrusion to obtain a bar stock.

[0056] After the bar stock undergoes surface machining (i.e., skin machining), it is subjected to a second hot extrusion, followed by a roll forming process to obtain a semi-finished product. The semi-finished product is then shaped by a die to obtain the particle-reinforced 7XXX aluminum alloy welding wire.

[0057] After the second hot extrusion, an aluminum-coated semi-finished welding wire is obtained. Then, the semi-finished welding wire is rolled to a size slightly larger than required by a roller die. However, the roundness of the semi-finished welding wire cannot be guaranteed at this time. Therefore, a final die shaping process is added to obtain the final product, namely particle-reinforced 7XXX aluminum alloy welding wire.

[0058] The present invention provides a method for preparing particle-reinforced 7XXX aluminum alloy welding wire, which can increase the content of reinforcing particles. The particle-reinforced 7XXX aluminum alloy welding wire prepared by this method can be used as a welding material for aluminum-based composite materials, and also as an additive material for manufacturing large and complex structural parts through arc additive manufacturing technology. Furthermore, the reinforcing particles in the welding wire are dispersedly distributed, and during the additive manufacturing process, due to the material's genetic effect, the reinforcing particles can also be uniformly distributed in the sample, thereby improving the sample performance.

[0059] Furthermore, the method for preparing particle-reinforced 7XXX aluminum alloy welding wire provided by the present invention improves the strength and hardness of the material after additive manufacturing. At the same time, additive manufacturing technology can be used to repair damaged parts, making maintenance simple and efficient, and significantly reducing costs.

[0060] Furthermore, the above preparation method can avoid the problem of difficulty in controlling the oxygen content and impurity elements of aluminum-based composite materials prepared by powder sintering. Therefore, the particle-reinforced 7XXX aluminum alloy welding wire prepared by this invention is more suitable as a welding material for secondary remelting.

[0061] In this invention, the composite welding wire is formed primarily by hot extrusion. Compared to sintering, this method eliminates the need for binders, preventing the introduction of binders as impurities into the welding wire. Simultaneously, the presence of the aluminum shell compresses the gaps between the powder particles when external force is applied, expelling air from the pores and significantly reducing the volume occupied by air within the shell, thus creating a denser internal structure and minimizing oxygen content.

[0062] Furthermore, using a pure aluminum shell as a protective measure forms a smooth pure aluminum skin (film) on the surface of the welding wire, which reduces the surface roughness of the welding wire and improves its feeding performance. This avoids the problem of surface roughness caused by the uniform distribution of reinforcing particles on the welding wire surface, which could damage the wire feeding mechanism during the feeding process and even affect the performance of the sample.

[0063] In a preferred embodiment, the temperature of the first hot extrusion and / or the second hot extrusion is 450 to 480°C, including but not limited to any one of 455°C, 460°C, 465°C, 470°C, 475°C, and 480°C, or a range between any two.

[0064] By using the above temperature range, the extrusion pressure can be significantly reduced and the stability of the welding wire improved without affecting its performance. It also avoids the phenomenon of brittle metal fracture caused by excessively high temperatures.

[0065] In a preferred embodiment, the diameter of the bar stock is 30-45 mm; including but not limited to any one of 30 mm, 33 mm, 35 mm, 40 mm, 43 mm, and 45 mm, or a range between any two.

[0066] In a preferred embodiment, the diameter of the particle-reinforced 7XXX aluminum alloy welding wire is 1.2 to 3.2 mm, including but not limited to any one of 1.5 mm, 2.0 mm, 2.3 mm, 2.5 mm, 2.8 mm, and 3.0 mm, or a range between any two; more preferably, it is 1.2 to 1.6 mm.

[0067] This invention controls the diameter of the bar stock and the diameter of the welding wire to meet different needs while maximizing the stability of the welding wire performance and improving the equipment's compatibility with the welding wire.

[0068] In a preferred embodiment, after the surface turning process, aluminum foil still remains on the surface of the bar stock. That is, the surface turning process does not completely remove the aluminum shell. This improves wire feeding performance and avoids damage to the wire feeding device caused by high surface roughness of the welding wire.

[0069] In a preferred embodiment, the thickness of the aluminum sheet is 0.9–2.5 mm. If the thickness of the removed aluminum sheet is too large, the aluminum sheet on the surface of the welding wire will be too thin, or even some parts of the welding wire will not be covered by aluminum sheet, which will affect the wire feeding performance.

[0070] Thirdly, the present invention provides the application of the aforementioned particle-reinforced 7XXX aluminum alloy welding wire in welding and arc additive manufacturing.

[0071] In one specific embodiment, the particle-reinforced 7XXX aluminum alloy welding wire is used for welding 7XXX aluminum alloys, and for arc additive manufacturing of high-strength complex structural components.

[0072] Among them, 7XXX aluminum alloy refers to the 7XXX series Al-Zn-Mg-Cu alloy.

[0073] The particle-reinforced 7XXX aluminum alloy welding wire prepared by this invention can be used as a welding material for aluminum-based composite materials, and also as an additive material for manufacturing large and complex structural parts through arc additive manufacturing technology, while meeting the requirements of material mechanical properties.

[0074] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0075] Example 1

[0076] The preparation method of the particle-reinforced 7XXX aluminum alloy welding wire provided in this embodiment includes the following steps:

[0077] (1) Weigh 6.5% Zn, 2.2% Mg, 1.6% Cu and the balance Al by mass percentage and melt them. Prepare Al-Zn-Mg-Cu alloy powder by atomization method. After sieving, obtain Al-Zn-Mg-Cu alloy powder with a particle size of 150-220 mesh.

[0078] (2) The Al-Zn-Mg-Cu alloy powder obtained in step (1) is weighed and mixed with SiC reinforcing particles with a particle size of 280-320 mesh at a volume ratio of 87:13.

[0079] (3) The powder mixed in step (2) is loaded into the prepared pure aluminum pressed shell;

[0080] (4) The shell containing alloy mixed powder obtained in step (3) is subjected to a first hot extrusion at 460°C to obtain a bar with a diameter of 40 mm.

[0081] (5) Perform surface machining on the bar obtained in step (4) to ensure that the bar has a pure aluminum sheet with a thickness of 2.1 mm on its surface;

[0082] (6) The bar stock after turning in step (5) is subjected to a second hot extrusion at 460°C, and then a semi-finished product is obtained by roller rolling process (room temperature cold rolling process). The semi-finished product is shaped by a mold to obtain an aluminum alloy welding wire with a diameter of 1.2 mm.

[0083] Example 2

[0084] The preparation method of the particle-reinforced 7XXX aluminum alloy welding wire provided in this embodiment includes the following steps:

[0085] (1) Weigh 6.2% Zn, 2.5% Mg, 1.3% Cu and the balance Al by mass percentage and melt them. Prepare Al-Zn-Mg-Cu alloy powder by atomization method. After sieving, obtain Al-Zn-Mg-Cu alloy powder with a particle size of 150-220 mesh.

[0086] (2) The Al-Zn-Mg-Cu alloy powder obtained in step (1) is weighed and mixed with SiC reinforcing particles with a particle size of 280-320 mesh at a volume ratio of 78:22.

[0087] (3) The powder mixed in step (2) is loaded into the prepared pure aluminum pressed shell;

[0088] (4) The shell containing alloy mixed powder obtained in step (3) is subjected to a first hot extrusion at 470°C to obtain a bar with a diameter of 40 mm.

[0089] (5) Perform surface machining on the bar obtained in step (4) to ensure that the bar has a pure aluminum sheet with a thickness of 1.6 mm on its surface;

[0090] (6) The bar stock after turning in step (5) is subjected to a second hot extrusion at 460°C, and then a semi-finished product is obtained by roller rolling process (room temperature cold rolling process). The semi-finished product is shaped by a mold to obtain an aluminum alloy welding wire with a diameter of 1.6 mm.

[0091] Example 3

[0092] The preparation method of the particle-reinforced 7XXX aluminum alloy welding wire provided in this embodiment includes the following steps:

[0093] (1) Weigh 6.0% Zn, 3.0% Mg, 1.4% Cu and the balance Al by mass percentage and melt them. Prepare Al-Zn-Mg-Cu alloy powder by atomization method. Obtain Al-Zn-Mg-Cu alloy powder with a particle size of 50-120 mesh by sieving.

[0094] (2) The Al-Zn-Mg-Cu alloy powder obtained in step (1) is weighed and mixed with Al2O3 reinforcing particles with a particle size of 150-200 mesh at a volume ratio of 92:8.

[0095] (3) The powder mixed in step (2) is loaded into the prepared pure aluminum pressed shell;

[0096] (4) The shell containing alloy mixed powder obtained in step (3) is subjected to a first hot extrusion at 450°C to obtain a bar with a diameter of 30 mm;

[0097] (5) Perform surface machining on the bar obtained in step (4) to ensure that the bar has a pure aluminum sheet with a thickness of 1.4 mm on its surface.

[0098] (6) The bar stock after turning in step (5) is subjected to a second hot extrusion at 450°C, and then a semi-finished product is obtained by roller rolling process (room temperature cold rolling process). The semi-finished product is shaped by a mold to obtain an aluminum alloy welding wire with a diameter of 1.5 mm.

[0099] Example 4

[0100] The preparation method of the particle-reinforced 7XXX aluminum alloy welding wire provided in this embodiment includes the following steps:

[0101] (1) Weigh 8.0% Zn, 1.8% Mg, 2.0% Cu and the balance Al by mass percentage and melt them. Prepare Al-Zn-Mg-Cu alloy powder by atomization method. After sieving, obtain Al-Zn-Mg-Cu alloy powder with a particle size of 230-300 mesh.

[0102] (2) Weigh the Al-Zn-Mg-Cu alloy powder obtained in step (1) and the reinforcing particles WC with a particle size of 230-270 mesh at a volume ratio of 80:20 and mix them together.

[0103] (3) The powder mixed in step (2) is loaded into the prepared pure aluminum pressed shell;

[0104] (4) The shell containing alloy mixed powder obtained in step (3) is subjected to a first hot extrusion at 480°C to obtain a bar with a diameter of 45 mm.

[0105] (5) Perform surface machining on the bar obtained in step (4) to ensure that the bar has a pure aluminum sheet with a thickness of 1.6 mm on its surface;

[0106] (6) The bar stock after turning in step (5) is subjected to a second hot extrusion at 480°C, and then a semi-finished product is obtained by roller rolling process (room temperature cold rolling process). The semi-finished product is shaped by a mold to obtain an aluminum alloy welding wire with a diameter of 2.5 mm.

[0107] Comparative Example 1

[0108] The preparation method of the 7XXX aluminum alloy welding wire provided in this comparative example is basically the same as that in Example 1, except that no reinforcing particles SiC are added in step (2).

[0109] Comparative Example 2

[0110] The preparation method of the particle-reinforced 7XXX aluminum alloy welding wire provided in this comparative example is basically the same as that in Example 1, except that in step (2), the volume ratio of Al-Zn-Mg-Cu alloy powder to reinforcing particles SiC is replaced with 97:3.

[0111] Comparative Example 3

[0112] The preparation method of the particle-reinforced 7XXX aluminum alloy welding wire provided in this comparative example is the powder sintering method, which specifically includes the following steps:

[0113] (1) Weigh 6.5% Zn, 2.2% Mg, 1.6% Cu and the balance Al by mass percentage and melt them. Prepare Al-Zn-Mg-Cu alloy powder by atomization method. After sieving, obtain Al-Zn-Mg-Cu alloy powder with a particle size of 150-220 mesh.

[0114] (2) Weigh the Al-Zn-Mg-Cu alloy powder obtained in step (1) and SiC reinforcing particles with a particle size of 280-320 mesh at a volume ratio of 87:13, and then weigh the binder at 5% of the total mass and mix them.

[0115] (3) The powder after mixing in step (2) is loaded into a cold isostatic pressing device for cold isostatic pressing molding, and then the cold isostatic pressing billet is degassed under vacuum.

[0116] (4) The billet in step (3) is hot isostatically pressed and sintered.

[0117] (5) Perform surface machining on the billet obtained in step (4) to ensure that the surface of the bar has a pure aluminum skin with a thickness of 2.1 mm.

[0118] (6) The bar stock after turning in step (5) is hot extruded at 460°C to obtain an aluminum alloy welding wire with a diameter of 1.2 mm.

[0119] Experimental Example 1

[0120] Welding wires prepared according to the above embodiments and comparative examples were used as welding materials for 10mm thick 7050-T6 aluminum alloy. The welding current was 120-150A, the voltage was 21-24V, and pure argon was used as the shielding gas with a flow rate of 17L / min. The mechanical properties of the weld were tested according to the national standard GB / T 228.1-2021 "Metallic materials, tensile testing—Part 1: Test at room temperature". The mechanical properties of the weld metal after welding are shown in Table 1.

[0121] Table 1 Results of mechanical property testing of welds

[0122]

[0123]

[0124] By comparing Example 1, Comparative Example 1 and Comparative Example 2, it can be seen that the addition of reinforcing particles and the amount of reinforcing particles both affect the mechanical properties of the weld metal. When the content of reinforcing particles is high, the weld strength is high, and when the amount of reinforcing particles is reduced, the weld strength decreases.

[0125] Comparing Example 1 and Comparative Example 3, it can be seen that when the alloy composition and reinforcing particle content are basically the same, changing the welding wire forming method by adding a binder will adversely affect the performance of the weld after welding. The tensile strength decreases from 579 MPa to 538 MPa, and the elongation of the weld also decreases sharply from 6% to 2%. The presence of the binder seriously deteriorates the mechanical properties of the weld.

[0126] also, Figure 1 This is a low-magnification macroscopic metallographic image of the cross-section of the particle-reinforced 7XXX aluminum alloy welding wire provided in Example 4. Figure 1 It can be seen that the reinforcing particles in the particle-reinforced 7XXX aluminum alloy welding wire prepared by this invention are uniformly distributed.

[0127] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A method for preparing a particle-reinforced 7XXX aluminum alloy welding wire, characterized in that, Includes the following steps: A mixture containing Al-Zn-Mg-Cu alloy powder and reinforcing particles is loaded into an aluminum shell and then subjected to a first hot extrusion to obtain a bar stock; the diameter of the bar stock is 30~45mm. After the bar stock is surface-machined, it undergoes a second hot extrusion, followed by a roll forming process to obtain a semi-finished product. The semi-finished product is then shaped by a die to obtain the particle-reinforced 7XXX aluminum alloy welding wire. After the surface turning treatment, the surface of the bar stock has an aluminum sheet with a thickness of 0.9~2.5mm. The volume of the reinforcing particles accounts for 5% to 25% of the sum of the volumes of the Al-Zn-Mg-Cu alloy powder and the reinforcing particles. The temperature of the first hot extrusion and / or the second hot extrusion is 450~480℃.

2. The method for preparing the particle-reinforced 7XXX aluminum alloy welding wire according to claim 1, characterized in that, The volume of the reinforcing particles accounts for 10% to 20% of the sum of the volumes of the Al-Zn-Mg-Cu alloy powder and the reinforcing particles.

3. The method for preparing the particle-reinforced 7XXX aluminum alloy welding wire according to claim 1, characterized in that, The Al-Zn-Mg-Cu alloy powder comprises the following components by mass percentage: Zn 5.9%~8.8%, Mg 1.4%~3.1%, Cu 1.3%~2.2%, Cr≤0.2%, with the balance being Al and other unavoidable impurities.

4. The method for preparing the particle-reinforced 7XXX aluminum alloy welding wire according to claim 1, characterized in that, The particle size of the Al-Zn-Mg-Cu alloy powder is 20~300 mesh.

5. The method for preparing the particle-reinforced 7XXX aluminum alloy welding wire according to claim 1, characterized in that, The particle size of the Al-Zn-Mg-Cu alloy powder is 150~220 mesh.

6. The method for preparing the particle-reinforced 7XXX aluminum alloy welding wire according to claim 1, characterized in that, The reinforcing particles include at least one of SiC, Al2O3, and WC.

7. The method for preparing the particle-reinforced 7XXX aluminum alloy welding wire according to claim 1, characterized in that, The particle size of the reinforcing particles is 150~400 mesh.

8. The method for preparing the particle-reinforced 7XXX aluminum alloy welding wire according to claim 1, characterized in that, The particle size of the reinforcing particles is 280~320 mesh.

9. The method for preparing the particle-reinforced 7XXX aluminum alloy welding wire according to claim 1, characterized in that, The rolling process includes room temperature cold rolling.

10. The method for preparing the particle-reinforced 7XXX aluminum alloy welding wire according to claim 1, characterized in that, The diameter of the particle-reinforced 7XXX aluminum alloy welding wire is 1.2~3.2mm.

11. The method for preparing the particle-reinforced 7XXX aluminum alloy welding wire according to claim 1, characterized in that, The diameter of the particle-reinforced 7XXX aluminum alloy welding wire is 1.2~1.6mm.

12. The application of the particle-reinforced 7XXX aluminum alloy welding wire prepared by the preparation method of any one of claims 1 to 11 in welding and arc additive manufacturing.

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