Aluminum alloy part, preparation method, aluminum alloy additive part and solid-phase additive manufacturing method

Abstract

The invention relates to an aluminum alloy part and a preparation method thereof, an aluminum alloy additive part and a solid-phase additive manufacturing method, and relates to the technical field of material development of aluminum alloy materials and additive manufacturing. According to the main technical scheme, the aluminum alloy part is used as a raw material of the solid-phase additive manufacturing process; wherein the aluminum alloy part comprises the following chemical components in percentage by weight: 7 to 15 percent of Mg, 0 to 1.4 percent of Mn, 0 to 5 percent of reinforcing elements, 0 to 0.5 percent of impurity elements and the balance of Al; wherein the reinforcing element comprises at least one of Ti, B, Zn, Cr, Ti, Zr, Sc and Cu elements; the impurity elements comprise Fe and / or Si. The solid-phase additive manufacturing method of the aluminum alloy additive part comprises the following steps that solid-phase additive manufacturing treatment AFED or AFSD is conducted on an aluminum alloy part, and the aluminum alloy additive part is obtained. The method is used for developing the aluminum alloy part to be suitable for the solid phase additive process, so that the prepared aluminum alloy additive part has the characteristics of being high in strength and free of heat treatment.

Description

Technical Field

[0001] This invention relates to the development of aluminum alloy materials and the field of additive manufacturing technology, and in particular to an aluminum alloy part and its preparation method, an aluminum alloy additive part and a solid-phase additive manufacturing method. Background Technology

[0002] Currently, commercially available high-strength aluminum alloys (such as 2xxx and 7xxx series) rely on precipitation strengthening mechanisms (θ' / S phase or η' phase). However, during the layer-by-layer deposition process of AFED or AFSD, thermomechanical coupling can lead to differentiated evolution of the precipitated phases, resulting in varying degrees of dissolution or coarsening, leading to uneven performance of the additive components. These issues force the components to undergo T6 heat treatment to readjust the microstructure, which not only increases energy consumption and process cycle time but may also cause deformation induced by thermal stress, making it difficult to meet the direct forming requirements of high-precision components.

[0003] While existing medium-strength aluminum alloys (such as the 5xxx and 6xxx series) can circumvent the requirements for phase transformation control, their AFED forming performance still has certain defects. Specifically, for the 5xxx series (Al-Mg): the dislocation annihilation effect caused by dynamic recrystallization during deposition results in a yield strength in the deposited state that is only 45-75% (≤200MPa) of the forging base material. For the 6xxx series (Al-Mg-Si): the β'' phase (Mg2Si) dissolves under thermomechanical action, requiring aging treatment to restore strength. Therefore, none of these material systems can meet the stringent requirements for direct forming yield strength (≥300MPa) and microstructure uniformity in aerospace load-bearing components or new energy chassis structural components.

[0004] Current alloy systems developed for laser / arc additive manufacturing utilize nanophases such as Al3(Sc, Zr) for strengthening. However, the Al-Mg matrix is ​​prone to Mg loss during deposition in molten additive manufacturing, leading to compositional fluctuations and porosity defects. Solid-state additive manufacturing, through high-speed rotating molds or rods, achieves intense plastic deformation, extrusion, and shearing of materials. The high-density grain boundaries generated during deposition hinder the long-range diffusion of solute atoms, and the resulting dislocations pin solute atoms, effectively preventing their migration and aggregation to precipitate sites. Combined with a significantly faster cooling rate than traditional casting, the processing system deviates from thermodynamic equilibrium, suppressing the formation kinetics of equilibrium phases. This holds promise for achieving the formation of supersaturated solid solutions of solid elements within the aluminum matrix.

[0005] In summary, there is an urgent need to develop an aluminum alloy part and its preparation method that are suitable for solid-state additive manufacturing processes, so that the prepared aluminum alloy additive parts have high strength and do not require heat treatment. Summary of the Invention

[0006] In view of this, the present invention provides an aluminum alloy part and its preparation method, an aluminum alloy additive part and a solid-phase additive manufacturing method, the main purpose of which is to develop an aluminum alloy part suitable for solid-phase additive manufacturing process, so that the prepared aluminum alloy additive part has high strength and heat treatment-free characteristics.

[0007] To achieve the above objectives, the present invention mainly provides the following technical solutions:

[0008] On one hand, embodiments of the present invention provide an aluminum alloy part, wherein the aluminum alloy part is used as a raw material for a solid-state additive manufacturing process; wherein, by weight fraction, the aluminum alloy part comprises the following chemical composition: Mg: 7~15wt%, Mn: 0~1.4wt%, reinforcing element: 0~5wt%, impurity element: 0~0.5wt%, balance Al; wherein the reinforcing element includes at least one of Ti, B, Zn, Cr, Zr, Sc, and Cu; and the impurity element includes Fe and / or Si.

[0009] Preferably, in the aluminum alloy part:

[0010] The Mn content is 0~1.4wt%, preferably 0.6~1.0wt%; and / or

[0011] The content of Ti is 0~0.2wt%, and the content of B is 0~0.1wt%; and / or

[0012] The Zn content is 0~0.8wt%, preferably 0.1~0.4wt%; and / or

[0013] The Cr content is 0~1.0 wt%, preferably 0.2~0.6 wt%; and / or

[0014] The Zr content is 0~0.5wt%, preferably 0.1~0.3wt%; and / or

[0015] The content of Sc element is 0~1wt%, preferably 0.1~0.5wt%; and / or

[0016] The Cu element content is 0~0.4wt%, preferably 0.1~0.2wt%.

[0017] Preferably, the aluminum alloy part is an aluminum alloy rod; preferably, the cross-sectional area of ​​the aluminum alloy rod is 9~900mm². 2 The length is ≥120mm; preferably, the aluminum alloy rod is a cast rod or an extruded rod; preferably, the density of the cast rod is ≥96%, the pore size is ≤500μm, and the grain size is 20~500μm; preferably, the density of the extruded rod is ≥98%, the pore size is ≤300μm, and the grain size is 20~300μm.

[0018] On the other hand, embodiments of the present invention also provide a method for preparing the above-mentioned aluminum alloy parts, which includes the following steps:

[0019] Smelting steps: The raw materials are melted and then kept at a constant temperature and stirred to obtain an aluminum alloy melt;

[0020] Casting and demolding steps: The aluminum alloy melt is cast and demolded to obtain an ingot;

[0021] The ingot can be used directly as an aluminum alloy part; or the ingot can be machined or hot-extruded to obtain an aluminum alloy part.

[0022] Preferably, if the ingot is used directly as an aluminum alloy part, the aluminum alloy part is a cast bar; if the ingot is used as an aluminum alloy part after machining, the aluminum alloy part is a cast bar; if the ingot is used as an aluminum alloy after hot extrusion, the aluminum alloy part is a hot extruded bar.

[0023] Preferably, in the smelting step, the raw materials include: aluminum-magnesium alloy and aluminum; preferably, they also include at least one intermediate alloy selected from aluminum-manganese alloy, aluminum-titanium diboride alloy, aluminum-zinc alloy, aluminum-chromium alloy, aluminum-zirconium alloy, aluminum-scandium alloy, and aluminum-copper alloy; preferably, the raw materials include aluminum-magnesium alloy with a magnesium content of 20-50 wt% and aluminum; preferably, they also include at least one intermediate alloy selected from: aluminum-manganese alloy with a manganese content of 10-25 wt%, aluminum-titanium diboride alloy with a TiB2 content of 5-10 wt%, aluminum-zinc alloy with a zinc content of 5-50 wt%, aluminum-chromium alloy with a chromium content of 5-20 wt%, aluminum-zirconium alloy with a zirconium content of 5-15 wt%, aluminum-scandium alloy with a scandium content of 2-10 wt%, and aluminum-copper alloy with a copper content of 20-50 wt%.

[0024] Preferably, in the melting step: the melting temperature is 680~750℃; the melting time is 30~50 minutes; and / or the temperature of the heat preservation and stirring treatment is 680~750℃, and the heat preservation and stirring time is 10~20 minutes.

[0025] Preferably, when the magnesium content of the raw material in the smelting step is ≥10wt%, an venting step is performed after the smelting step and before the casting and demolding steps to control the density of the ingot. Preferably, the venting step includes: in a ≤10wt% magnesium content... - Under a vacuum environment of 2Pa, the aluminum alloy melt is left to stand for 10-15 minutes. The dissolved hydrogen in the melt is removed by using the vacuum negative pressure. Argon gas is then introduced and continued for 5-10 minutes.

[0026] Preferably, in the casting and demolding steps: before casting, the following pretreatment is required: adjust the temperature of the aluminum alloy melt to the casting temperature, wherein the casting temperature is 680~700℃; preheat the casting mold to 200~250℃, and spray a release agent into the mold;

[0027] Preferably, in the casting and demolding steps: the demolding treatment is a shrinkage-compensating demolding treatment; preferably, during the shrinkage-compensating demolding treatment: the cooling rate is controlled at 1~5K / s to reduce the tendency of shrinkage cavities in the ingot; preferably, a heating riser is provided at the top of the casting mold, and insulating sand is filled at or near the heating riser to delay the solidification of the riser and achieve the shrinkage-compensating design; wherein, the volume of the heating riser is 10~15% of the ingot volume;

[0028] Preferably, the demolding process is carried out after the ingot has cooled to below 150°C;

[0029] Preferably, after demolding, the oxide scale and residual release agent on the surface of the ingot are removed by machining or sandblasting.

[0030] Furthermore, embodiments of the present invention also provide a solid-state additive manufacturing method for aluminum alloy additive parts, comprising the following steps:

[0031] A solid-state additive manufacturing process (AFED) is performed on any of the aluminum alloy parts described above to obtain an aluminum alloy additive part; or a solid-state additive manufacturing process (AFSD) is performed on any of the aluminum alloy parts described above to obtain an aluminum alloy additive part.

[0032] Preferably, during the solid-phase additive manufacturing process AFED:

[0033] Using any of the above-mentioned aluminum alloy parts as raw materials, under the pressure of the feeding mechanism, the raw materials are fed to a rotating friction extrusion deposition die, and rub against the inner surface of the friction extrusion deposition die, so that the raw materials near the extrusion port of the friction extrusion deposition die reach a viscoplastic rheological state due to friction and deformation heat; the softened material is pushed axially under the action of the feeding mechanism, extruded from the extrusion port and deposited on the surface of the substrate, and moved laterally along the predetermined additive path and repeated multiple times to obtain an aluminum alloy additive part;

[0034] The feeding speed is 25~180mm / min, preferably 30~150mm / min; the rotation speed of the friction extrusion deposition mold is 300~1000rpm, preferably 400~800rpm; the travel speed is 50~1000mm / min, preferably 200~600mm / min; and the thickness of a single deposition layer is 0.5~2mm, preferably 0.8~1.6mm.

[0035] Preferably, during the solid-phase additive manufacturing process of AFSD:

[0036] Using any of the above-mentioned aluminum alloy parts as raw materials, the raw materials rotate together with the stirring head of the AFSD device. Under the action of axial force, the raw materials are fed and the ends of the raw materials reach a viscoplastic rheological state after friction with the substrate or the deposited layer. The softened material at the ends of the raw materials is pushed along the axial direction and deposited on the surface of the substrate. It moves laterally along the predetermined additive path and repeats multiple times to obtain an aluminum alloy additive part.

[0037] The feeding speed is 25~120mm / min, preferably 30~80mm / min; the rotation speed of the stirring head of the AFSD device is 500~1200rpm, preferably 500~1000rpm; the traveling speed is 50~800mm / min, preferably 100~500mm / min; and the thickness of the single-layer deposition layer is 0.5~2mm, preferably 0.8~1.6mm.

[0038] Preferably, during the solid-phase additive manufacturing process of AFED or AFSD: the substrate and the deposited layer are cooled by immersing them in a coolant to control the cooling rate of AFED or AFSD to above 30°C / s.

[0039] In another aspect, embodiments of the present invention also provide an aluminum alloy additive manufacturing part, wherein the aluminum alloy additive manufacturing part is prepared by the solid-state additive manufacturing method of the aluminum alloy additive manufacturing part described in any one of the above claims; wherein the yield strength of the aluminum alloy additive manufacturing part is ≥300MPa;

[0040] Preferably, the matrix structure of the aluminum alloy additive part is a supersaturated solid solution; the grain size of the aluminum alloy additive part is 0.8~3.5μm.

[0041] Preferably, the yield strength of the aluminum alloy additive part is 300~450MPa.

[0042] Compared with the prior art, the aluminum alloy parts and their preparation methods, aluminum alloy additive parts and solid-phase additive manufacturing methods of the present invention have at least the following beneficial effects:

[0043] On one hand, embodiments of the present invention provide an aluminum alloy part, which is used as a raw material for a solid-state additive manufacturing process; wherein, by weight fraction, the aluminum alloy part comprises the following chemical composition: Mg: 7~15wt%, Mn: 0~1.4wt%, reinforcing element: 0~5wt%, impurity element: 0~0.5wt%, balance Al; wherein the reinforcing element includes at least one of Ti, B, Zn, Cr, Zr, Sc, and Cu; the impurity element includes Fe and / or Si. Preferably, the above-mentioned aluminum alloy part is a bar. The above solution is explained as follows: In the prior art, casting base materials with high magnesium content are difficult to promote because the ingots have many pores, making subsequent processing prone to cracking. With increased Mg content, the Al3Mg2 phase preferentially segregates at the grain boundaries of the ingot alloy, affecting corrosion resistance. Unlike existing technologies, the aluminum alloy part designed in this invention has an increased Mg content, and its preparation process is inexpensive. Although it has the aforementioned problems, it is compatible with solid-state additive manufacturing and suitable as a raw material for this technology. After preparation using AFED / AFSD technology, a dense additive part is formed with a porosity below 0.01%. Mg element forms a supersaturated solid solution in the matrix, and no Mg element segregation was observed. The principle of this compatibility is as follows: the low heat input characteristics of AFED / AFSD technology can effectively suppress Mg element burn-off, ensuring compositional stability and the forming quality of the deposited component. At the same time, the intense plastic deformation of the stirring friction deposition process achieves supersaturated diffusion dissolution of solid solution elements. During the stirring friction deposition process, the material undergoes dynamic recrystallization, transforming from coarse grains in the parent material to fine equiaxed grains within the deposited component.

[0044] On the other hand, embodiments of the present invention provide a method for preparing aluminum alloy parts, comprising the following steps: melting raw materials to obtain an aluminum alloy melt; mechanically or manually stirring the aluminum alloy melt; casting and demolding the aluminum alloy melt to obtain an ingot; using the ingot directly as an aluminum alloy part; or machining or hot extruding the ingot to obtain an aluminum alloy part. It should be noted that the above scheme achieves low-cost, large-scale preparation of base materials through casting, unlike existing technologies that use finely ground metal powders or rolled dense alloys. This technology has broader requirements for the density and the size and distribution of phase precipitation within the material. The cast base material achieves short-process preparation of dense, supersaturated, high-magnesium-content deposited components through agitation-friction-extrusion deposition technology.

[0045] In another aspect, embodiments of the present invention provide a solid-state additive manufacturing method for aluminum alloy additive parts, comprising the following steps: performing solid-state additive manufacturing (AFED) on the aluminum alloy parts described in any of the above claims to obtain aluminum alloy additive parts. Specifically, in order to prepare the aluminum alloy parts (bars) with the above composition into dense additive parts, and to give the additive parts high strength and heat-free characteristics, the present invention sets the AFED process parameters as follows: feed rate of 25~180 mm / min, preferably 30~150 mm / min; rotational speed of the friction extrusion deposition die of 300~1000 rpm, preferably 400~800 rpm; travel speed of 50~1000 mm / min, preferably 200~600 mm / min; and single-layer deposition thickness of 0.5~2 mm, preferably 0.8~1.6 mm.

[0046] In another aspect, embodiments of the present invention provide a solid-state additive manufacturing method for aluminum alloy additive parts, comprising the following steps: performing solid-state additive manufacturing (AFSD) on the aluminum alloy parts described in any of the above claims to obtain aluminum alloy additive parts. Specifically, in order to prepare the aluminum alloy parts (bars) of the above composition into dense additive parts, and to give the additive parts high strength and heat-free characteristics, the present invention sets the AFSD process parameters as follows: feed rate of 25~120 mm / min, preferably 30~80 mm / min; rotational speed of the stirring head of the AFSD device of 500~1200 rpm, preferably 500~1000 rpm; travel speed of 50~800 mm / min, preferably 100~500 mm / min; and single-layer deposition thickness of 0.5~2 mm, preferably 0.8~1.6 mm.

[0047] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0048] Figure 1 This is a metallographic image of the cross-section of the aluminum alloy bar in Comparative Example 1;

[0049] Figure 2 This is a metallographic image of the cross-section of the aluminum alloy bar in Example 2;

[0050] Figure 3 This is a cross-sectional metallographic image of the aluminum alloy additive part in Comparative Example 1;

[0051] Figure 4 This is a cross-sectional metallographic image of the aluminum alloy additive part in Example 2;

[0052] Figure 5 This is a grain structure diagram of an aluminum alloy rod; among which, Figure 5Figure (a) in the figure is a grain structure diagram of the aluminum alloy bar in Example 1; Figure 5 Figure (b) is a grain structure diagram of the aluminum alloy rod in Example 2;

[0053] Figure 6 This is a grain structure diagram of the aluminum alloy additive part in Comparative Example 1;

[0054] Figure 7 This is a grain structure diagram of the aluminum alloy additive part in Example 2;

[0055] Figure 8 This is a scanning electron microscope image of the aluminum alloy bar in Comparative Example 2;

[0056] Figure 9 This is a schematic diagram of the solid-state additive manufacturing processes AFED and AFSD provided in the embodiments of the present invention. Detailed Implementation

[0057] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0058] This invention provides an aluminum alloy part, an aluminum alloy additive part, and a solid-phase additive manufacturing method. Through composition design and process optimization, it solves the contradiction of "high performance-short process-low cost" faced by traditional aluminum alloys in solid-phase additive manufacturing, and is suitable for manufacturing high-performance lightweight components in aerospace, new energy vehicles and other fields.

[0059] This invention produces an aluminum alloy part suitable for solid-phase additive manufacturing. By adjusting the processing parameters and immersing the deposited layer in a coolant (such as cooling water, ethylene glycol aqueous solution, liquid nitrogen, etc.), the heat input during the deposition process can be precisely controlled, reducing the coarsening or dissolution of the precipitated phase.

[0060] This technology enables deposited components to achieve uniform microstructure and excellent strength (yield strength ≥300MPa) without heat treatment, significantly reducing energy consumption and production costs, and shortening the production cycle.

[0061] Using high-magnesium-content (7~15wt%) aluminum alloys as the matrix, traditional melt additive manufacturing processes are prone to magnesium loss due to high temperatures, leading to compositional fluctuations and porosity defects. However, the low heat input characteristics of AFED (Additive Friction Extrusion Deposition) technology (deposition temperature below the material's melting point) effectively suppress magnesium volatilization (loss rate <0.1 wt.%), ensuring compositional stability and the quality of the deposited components. Simultaneously, the intense plastic deformation caused by frictional deposition allows for the supersaturated diffusion dissolution of solid solution elements.

[0062] The main solution of the present invention is as follows:

[0063] On one hand, embodiments of the present invention provide an aluminum alloy part, wherein the aluminum alloy part is used as a raw material for a solid-state additive manufacturing process; wherein, by weight fraction, the aluminum alloy part comprises the following chemical composition:

[0064] Mg: 7~15wt%, Mn: 0~1.4wt%, reinforcing element: 0~5wt%, balance Al; wherein the reinforcing element includes at least one of Ti, B, Zn, Cr, Zr, Sc, and Cu.

[0065] It should be noted that: the high Mg content only needs to be uniformly distributed within the casting. In the base material, a large amount of Mg actually segregates at the grain boundaries, and after deposition, Mg can achieve supersaturated solid solution, thus redistributing the Mg element. Zn, Cr, Zr, and Cu are used to form Zn and Cu solute atom enrichment regions and / or granular phases (MgZn2, Al7Cr, Al3Zr, Al2Cu) to assist in strengthening the performance.

[0066] It should be noted that the Mg content is preferably 7-12 wt%. Excessive Mg may affect the plasticity of the cast alloy and its machinability using AFED technology.

[0067] The content of Mn element is 0~1.4wt%, with a preferred range of 0.6~1.0wt%. It inhibits grain boundary migration by forming Al6Mn dispersed phase in the aluminum matrix. At the same time, Mn element preferentially reacts with Fe impurities to form Al6(Fe,Mn) phase, which reduces the harm of Fe impurities to toughness. Excessive Mn and Cr elements will lead to coarse Al6Mn phase, affecting the final processing performance.

[0068] Preferably, the Zn content is 0~0.8wt%, more preferably 0.1~0.4wt%, as excessive Zn can lead to stress corrosion cracking. The Cu content is 0~0.4wt%, more preferably 0.1~0.2wt%, as excessive Cu can cause intergranular corrosion. If Zn and Cu are added simultaneously, the total Zn and Cu content is preferably less than 0.5wt% to avoid the formation of complex precipitates that could affect the uniformity of the deposited structure, thus ensuring the corrosion resistance of the deposited component and the stability of the internal structure.

[0069] Preferably, the Cr content is 0~1.0wt%, more preferably 0.2~0.6wt%; grain boundary migration is suppressed by forming a dispersed Al7Cr phase in the aluminum matrix; excessive Cr will lead to coarse Al7Cr phase, affecting the final processing performance.

[0070] Preferably, the Ti element content is 0~0.2wt%, and the B element content is 0~0.1wt%. Ti element usually forms Al3Ti and TiB2 with Al and B elements to enhance the grain refinement effect. Excessive Ti and B elements will lead to increased brittleness of the material and particle agglomeration.

[0071] Preferably, the Zr content is 0~0.5wt%, more preferably 0.1~0.3wt%. The Sc content is 0~1wt%, more preferably 0.1~0.5wt%. Excessive Zr and Sc will cause Al3Zr and Al3Sc phases to aggregate, weaken the strengthening effect, increase the brittleness of the material, and reduce the machinability of the cast bar base material.

[0072] In the aluminum alloy castings, the content of impurity elements is <0.5wt%; wherein the impurity elements include Fe and / or Si.

[0073] Preferably, the aluminum alloy part is an aluminum alloy rod; more preferably, the cross-sectional area of ​​the aluminum alloy rod is 9~900mm². 2 The length is ≥120mm; preferably, the aluminum alloy rod is a cast rod or an extruded rod; preferably, the density of the cast rod is ≥96%, the pore size is ≤500μm, and the grain size is 20~500μm; preferably, the density of the extruded rod is ≥98%, the pore size is ≤300μm, and the grain size is 20~300μm.

[0074] On the other hand, embodiments of the present invention provide a method for preparing an aluminum alloy part, which includes the following steps:

[0075] Melting steps: The raw materials are placed in a vacuum melting furnace and then melted and stirred in sequence to obtain aluminum alloy melt.

[0076] The melting process involves controlling the temperature at 680~750℃ (keeping the temperature below 750℃ to prevent Mg combustion; the melting temperature decreases as the Mg content increases), and the melting time is 30~50 minutes (melting until the added intermediate alloy and aluminum are completely liquefied). The holding and stirring process is carried out at 680~750℃ (stirring ensures uniform Mg distribution), and the holding and stirring time is 10~20 minutes.

[0077] The raw materials include aluminum-magnesium alloy with a magnesium content of 20-50 wt% and aluminum; preferably, they also include at least one intermediate alloy selected from the following: aluminum-manganese alloy with a manganese content of 10-25 wt%, aluminum-titanium diboride alloy with a TiB2 content of 5-10 wt% (a casting refiner used to refine the grain size of the casting alloy and make the grains in the casting alloy more uniform), aluminum-zinc alloy with a zinc content of 5-50 wt%, aluminum-chromium alloy with a chromium content of 5-20 wt%, aluminum-zirconium alloy with a zirconium content of 5-15 wt%, aluminum-scandium alloy with a scandium content of 2-10 wt%, and aluminum-copper alloy with a copper content of 20-50 wt%.

[0078] Exhaust procedure: Maintain a vacuum environment (≤10) -2 (Pa), let stand for 10-15 minutes, then remove dissolved hydrogen (H2) from the melt using vacuum negative pressure, and introduce high-purity argon gas (flow rate 1-2 L / min) to assist in degassing for 5-10 minutes. This step is only performed when the magnesium content in the raw material is ≥10wt%.

[0079] Casting Procedure: Before casting, the following pretreatment is required: Adjust the melt to a casting temperature of 680-700℃ to avoid magnesium burn-out and ensure the fluidity of Zr, Cr, etc. Simultaneously, preheat the steel metal mold to 200-250℃ and spray with a release agent to a thickness ≤50μm.

[0080] Feeding and Demolding: Adjust the cooling rate by wrapping the ingot with insulating cotton to control the cooling rate at 1~5K / s, thereby reducing the tendency of shrinkage cavities in the ingot. A heating riser (10~15% of the ingot volume) is installed at the top and filled with insulating sand to delay riser solidification, achieving the feeding design. After the ingot cools to below 150℃, demold it and remove surface oxide scale and residual release agent using machining or sandblasting.

[0081] The ingot can be used directly as an aluminum alloy part; or the ingot can be machined or hot-extruded to obtain an aluminum alloy part. If the ingot is used directly as an aluminum alloy part, the aluminum alloy part is a cast bar; if the ingot is machined (turning or wire cutting) and then used as an aluminum alloy part, the aluminum alloy part is a cast bar; if the ingot is hot-extruded and then used as an aluminum alloy part, the aluminum alloy part is a hot-extruded bar. For ingots with small cross-sections, they can be used directly as aluminum alloy parts; for ingots with large cross-sections, aluminum alloy parts are obtained through machining or hot extrusion.

[0082] It should be noted that high-magnesium-content ingots are prone to cracking if subjected to high-strain rolling.

[0083] In another aspect, embodiments of the present invention provide a solid-state additive manufacturing method for aluminum alloy additive parts, which includes the following steps: performing solid-state additive manufacturing treatment AFED on the aluminum alloy parts to obtain aluminum alloy additive parts; or performing solid-state additive manufacturing treatment AFSD on the aluminum alloy parts to obtain aluminum alloy additive parts. Figure 9 This is a schematic diagram of the solid-state additive manufacturing processes AFED and AFSD provided in the embodiments of the present invention, wherein, in Figure 9 In the diagram, the solid-state additive manufacturing process diagram on the left is the AFED diagram, and the solid-state additive manufacturing process diagram on the right is the AFSD diagram.

[0084] Preferably, in the solid-phase additive manufacturing process (AFED): an aluminum alloy part is used as raw material. Under the pressure of the feeding mechanism, the raw material is fed to a rotating friction extrusion deposition die and rubs against the inner surface of the friction extrusion deposition die, causing the raw material near the extrusion port of the friction extrusion deposition die to reach a viscoplastic rheological state due to friction and deformation heat. The softened material is pushed axially under the action of the feeding mechanism, extruded from the extrusion port and deposited on the surface of the substrate, and moved laterally along the predetermined additive path and repeated multiple times to obtain an aluminum alloy additive part.

[0085] The feed rate is 25~180 mm / min, preferably 30~150 mm / min; the rotational speed of the friction extrusion deposition die is 300~1000 rpm, preferably 400~800 rpm; the travel speed is 50~1000 mm / min, preferably 200~600 mm / min; and the thickness of a single deposited layer is 0.5~2 mm, preferably 0.8~1.6 mm. Preferably, the peak temperature of AFED is controlled below 400℃.

[0086] Preferably, in the solid-phase additive manufacturing process AFSD: aluminum alloy parts are used as raw materials. The raw materials rotate together with the stirring head of the AFSD device. Under the action of axial force, the raw materials are fed and reach a viscoplastic rheological state after the ends of the raw materials rub against the substrate or the deposited layer. The softened material at the ends of the raw materials is pushed forward along the axial direction and deposited on the surface of the substrate. It moves laterally along the predetermined additive path and repeats multiple times to obtain an aluminum alloy additive part.

[0087] The feeding speed is 25~120mm / min, preferably 30~80mm / min; the rotation speed of the stirring head of the AFSD device is 500~1200rpm, preferably 500~1000rpm; the traveling speed is 50~800mm / min, preferably 100~500mm / min; and the thickness of the single-layer deposition layer is 0.5~2mm, preferably 0.8~1.6mm.

[0088] It should be noted that: (1) "Feeding speed" refers to the length of the bar stock extruded downwards per minute under the pressure of the feeding mechanism. Combined with the bar stock diameter, the volume of viscoplastic rheological alloy extruded from the extruder per minute can be obtained. (2) "Travel speed" is the speed at which the AFED extrusion die or the stirring head of the AFSD device moves along the additive path. Through this movement, the previously extruded viscoplastic rheological alloy is evenly coated on the target path, achieving a layered additive state.

[0089] Preferably, during the solid-phase additive manufacturing process of AFED or AFSD: the substrate and deposited layer are cooled by immersing them in a coolant (e.g., cooling water, aqueous ethylene glycol solution, liquid nitrogen, etc.) to achieve rapid cooling, with the cooling rate controlled above 30°C / s. (At room temperature, the supersaturation of Mg in the aluminum matrix is ​​3.0~3.5wt%. If the cooling rate is slow, Mg will slowly precipitate from the prepared supersaturated solid solution after deposition, forming the corresponding Al3Mg2 phase segregating on the grain boundaries, thus failing to maintain the Mg content of the supersaturated solid solution. Rapid cooling is equivalent to freezing the atoms in a disguised way, preventing movement and phase precipitation, and achieving Mg supersaturation solid solution.) AFED or AFSD itself refines the dense grain structure after the deposition of defective rods. During this rapid plastic deformation process, Mg achieves supersaturated solid solution. Timely rapid cooling achieves Mg supersaturation solid solution, generating GP regions with certain thermal stability, ensuring mechanical properties.

[0090] Regarding the above-described solution of the present invention, the following should be noted:

[0091] 1) The aluminum alloy parts designed in this invention have increased Mg content. In the prior art, casting base materials with high magnesium content are difficult to promote because the ingots have many pores and are prone to cracking during subsequent processing. After the Mg content is increased, the Al3Mg2 phase preferentially segregates at the grain boundaries of the ingot alloy, affecting corrosion resistance.

[0092] The aluminum alloy parts of the present invention are produced inexpensively using a casting method. Although the above-mentioned problems exist, after preparation by AFED / AFSD technology, a dense component is formed with a porosity of less than 0.01%, and a supersaturated solid solution (Mg element supersaturated solid solution in Al matrix) is formed in the matrix. No Mg element segregation phenomenon was found.

[0093] 2) This invention achieves high-performance, low-cost manufacturing of aluminum alloy additive parts through the following innovations: ① Breaking through the Mg content limit of commercial alloys, low density (2.6 g / cm³) is achieved through casting followed by AFED or AFSD. 3 The technology achieves the following characteristics: 1) High strength and plasticity matching (yield strength ≥300MPa, elongation ≥20%); 2) Addition of Mn element forms Al6Mn dispersed phase to inhibit grain boundary migration and preferentially reacts with Fe impurities to form Al6(MnFe) phase to eliminate the ductility and toughness hazards of Fe element; 3) If Zr / Sc / TiB2 element is introduced, Al3(Zr,Sc,Ti) / TiB2 nanoparticles are generated, which synergistically enhance the strength of the deposited state and the high-temperature softening resistance; 4) If Zn and Cu elements are introduced, Zn / Cu is strictly controlled (≤0.5wt%) to avoid the formation of complex precipitates and ensure the stability of the microstructure; 5) The content of impurities such as Fe and Si is controlled to ensure effective solid solution of Mg element. This technology enables low-cost large-scale production of solid-phase deposited parent materials, with comprehensive performance superior to existing commercial high-strength aluminum alloys.

[0094] 3) This invention utilizes low-cost, cast-state homogenized base material for direct AFED or AFSD forming. By preparing a base material with a high content of the solid-solution element Mg, supersaturated solid solution is achieved after deposition. By matching process parameters with dynamic recrystallization behavior (the recrystallization phenomenon occurring during hot deformation), synergistic control is achieved between grain refinement (average grain size <3μm, 97.0% refinement compared to the base material), high strength (tensile strength >500MPa, yield strength >300MPa), and high elongation (>20%). Furthermore, controlling the content of elements such as Si, Cu, and Zn avoids the formation of complex precipitates, resulting in a dense, uniform microstructure and excellent mechanical properties in a heat-free additive manufacturing component.

[0095] 4) During the AFED or AFSD process, this invention controls the feed rate, die rotation speed, and die travel speed. The feed rate affects the downward pressure, the die rotation speed affects frictional heat generation and the rate of plastic deformation, and the travel speed affects the heat input and strain rate. Dynamic recrystallization (the dynamic recrystallization of the cast base material grains under thermal stress after the frictional extrusion deposition step) is the process by which new grains are formed in the cast base material during the high-temperature deformation of AFED or AFSD, resulting in new crystal nuclei. The deposited fine new grains replace the coarse structure of the cast base material. It should be noted that low rotation speed, high travel speed, and low feed rate result in low heat input; low heat input leads to less dislocation annihilation and higher performance. As the Mg content in the bar increases, the heat input must be reduced because high Mg content lowers the overall melting point of the material. High heat input can easily lead to porosity defects because the material cannot bond tightly with the base plate in time and is partially carried away by the die while still softened, ultimately forming obvious porosity.

[0096] The following specific examples further illustrate this point:

[0097] Example 1

[0098] This embodiment prepares an aluminum alloy part and an aluminum alloy additive part; the main steps include the following:

[0099] Step 1): Combine pure aluminum (balance), Al-20wt%Mg master alloy, Al-10wt%Mn master alloy, Al-5wt%TiB2 master alloy, Al-10wt%Zr master alloy, Al-5wt%Cr master alloy, and Al-50wt%Cu master alloy. The total mass of the above raw materials is 10 kg. The amount of the above master alloys used must ensure that the content of Mg in the raw materials is 7wt%, Mn is 0.8wt%, TiB2 is 0.05wt% (Ti is 0.034wt%, B is 0.016wt%), Zr is 0.2wt%, Cr is 0.3wt%, and Cu is 0.1wt%.

[0100] The above raw materials were placed in a vacuum furnace at 700°C for melting treatment (melting time was 40 minutes) and then kept warm and stirred. The stirring treatment lasted for 10 minutes to ensure uniform dispersion of the elements and obtain aluminum alloy melt.

[0101] Step 2): Cool the aluminum alloy melt to 690℃ and pour it into a preheated steel mold at 220℃ (sprayed with 40μm boron nitride release agent), with the bottom flow rate controlled at 0.8kg / s;

[0102] The cast ingot is wrapped with insulating cotton for slow cooling (3K / s), and a heating riser is installed at the top (the riser volume is 12% of the ingot volume), which is filled with insulating sand. After cooling to 120℃, the ingot is demolded, and sandblasting is used to remove the surface oxide scale and residual release agent.

[0103] Step 3): Cut the ingot into bars of Φ12mm×200mm.

[0104] Step 4): Perform solid-state additive manufacturing (AFED) on the bar to obtain an aluminum alloy additive part.

[0105] The following parameters were selected for AFED additive manufacturing: feed rate of 50 mm / min; die speed of 600 rpm; travel speed of 200 mm / min; and single-layer thickness of 0.8 mm.

[0106] During the AFED process, the substrate and deposited layer are immersed in cooling water (5-20℃) to cool them, thereby controlling the AFED cooling rate to above 30℃ / s. The peak temperature of AFED is controlled between 350-400℃.

[0107] No obvious pores or cracks were observed in the aluminum alloy additive parts obtained in this embodiment. The overall cross-section was dense and free of pores. This proves that the aluminum alloy parts (bars) prepared above can be used to produce dense aluminum-magnesium based aluminum alloy samples of this series through AFED technology.

[0108] In this embodiment, the average grain size of the aluminum alloy additive part is 2.5 micrometers. The maximum tensile strength of the additive part along the length, width and height directions is 471 MPa, 480 MPa and 417 MPa respectively, the average yield strength is 300 MPa and the average elongation is 23%.

[0109] Example 2

[0110] This embodiment prepares an aluminum alloy part and an aluminum alloy additive part. The difference between this embodiment and embodiment 1 is that steps 1) and 5) are different, while other steps and parameters are the same as in embodiment 1.

[0111] In this embodiment, steps 1) and 5) are as follows:

[0112] Step 1): Combine pure aluminum (balance), Al-20wt%Mg master alloy, Al-10wt%Mn master alloy, Al-5wt%TiB2 master alloy, Al-10wt%Zr master alloy, Al-5wt%Cr master alloy, and Al-50wt%Cu master alloy. The total mass of the above raw materials is 10 kg. The amount of the above master alloys used must ensure that the content of Mg in the raw materials is 9wt%, Mn is 1wt%, TiB2 is 0.1wt% (Ti content is 0.069wt%, B content is 0.031wt%), Zr is 0.25wt%, Cr is 0.4wt%, and Cu is 0.1wt%.

[0113] The above raw materials were placed in a vacuum furnace at 700°C for melting treatment (melting time was 35 minutes) and then kept warm and stirred. The stirring treatment lasted for 10 minutes to ensure that the elements were evenly dispersed, thus obtaining an aluminum alloy melt.

[0114] Step 5): Perform solid-state additive manufacturing (AFED) on the bar to obtain an aluminum alloy additive part.

[0115] The following parameters were selected for AFED additive manufacturing: feed rate of 100 mm / min; die rotation speed of 550 rpm; travel speed of 400 mm / min; and single-layer thickness of 0.8 mm. During the AFED process, the substrate and deposited layer were immersed in an ethylene glycol aqueous solution (coolant temperature -5 to 10℃) for cooling to control the AFED cooling rate at a rate above 35℃ / s.

[0116] The cross-sectional metallographic image of the cast aluminum alloy bar obtained in Example 2 is shown below. Figure 2 As shown, from Figure 2 It can be seen that the aluminum alloy rod contains a certain number of large pores. Obvious grains are visible to the naked eye. The grain structure diagram of the cast rod obtained through EBSD analysis is shown below. Figure 5 As shown in Figure (b), the average grain size of the cast aluminum alloy bar with a Mg content of 9 wt% is 77 micrometers.

[0117] No obvious pores or cracks were observed in the aluminum alloy additive part prepared in Example 2. The cross-sectional metallographic image of the aluminum alloy additive part is shown below. Figure 4 As shown, the cross-section of the additive part is dense and free of pores, which proves that dense samples with high magnesium content in this series of aluminum-magnesium-based aluminum alloys can be produced using the above-mentioned aluminum alloy parts (bars) through AFED technology.

[0118] The grain structure of the aluminum alloy additive part prepared in Example 2 is as follows: Figure 7 As shown, the average grain size is 2.3 μm.

[0119] Furthermore, the maximum tensile strength of the aluminum alloy additive part prepared in Example 2 along the additive length direction, width direction and height direction is 508MPa, 517MPa and 470MPa, respectively, the average yield strength is 312MPa and the average elongation is 22%.

[0120] Example 3

[0121] This embodiment prepares an aluminum alloy part and an aluminum alloy additive part. The difference between this embodiment and Embodiment 1 is that steps 1) and 5) are different, while other steps and parameters are the same. Specifically, steps 1) and 5) of this embodiment are as follows:

[0122] Step 1): Combine pure aluminum (balance), Al-20wt%Mg master alloy, Al-10wt%Mn master alloy, Al-5wt%TiB2 master alloy, Al-10wt%Zr master alloy, Al-20wt%Zn master alloy, and Al-50wt%Cu master alloy. The total mass of the above raw materials is 10 kg. The amount of the above master alloys used must ensure that the content of Mg in the raw materials is 11wt%, Mn is 0.8wt%, TiB2 is 0.05wt% (Ti is 0.034wt%, B is 0.016wt%), Zr is 0.2wt%, Zn is 0.1wt%, and Cu is 0.1wt%.

[0123] The above raw materials were placed in a vacuum furnace at 700°C for melting treatment (melting time was 30 minutes) and then kept warm and stirred. The stirring treatment lasted for 10 minutes to ensure uniform dispersion of the elements and obtain aluminum alloy melt.

[0124] Under a vacuum environment of ≤10²Pa, the aluminum alloy melt was left to stand for 10 minutes, and the dissolved hydrogen in the melt was removed by using vacuum negative pressure. Argon gas was then introduced for 10 minutes.

[0125] Step 5): Perform solid-state additive manufacturing (AFED) on the bar to obtain an aluminum alloy additive part.

[0126] The following parameters were selected for AFED additive manufacturing: feed rate of 150 mm / min; die speed of 500 rpm; travel speed of 600 mm / min; and single-layer thickness of 0.8 mm. During the AFED process, the substrate and deposited layer were immersed in cooling water (5-20℃) for cooling, and the AFED cooling rate was controlled at above 30℃ / s.

[0127] In this embodiment, no obvious pores or cracks were observed in the aluminum alloy additive part. The maximum tensile strength of the aluminum alloy additive part along the length, width, and height directions were 553 MPa, 540 MPa, and 516 MPa, respectively, with an average yield strength of 334 MPa and an average elongation of 18%.

[0128] Example 4

[0129] This embodiment prepares an aluminum alloy part and an aluminum alloy additive part. The difference between this embodiment and Embodiment 1 is that steps 1) and 5) are different, while other steps and parameters are the same. Specifically, steps 1) and 5) of this embodiment are as follows:

[0130] Step 1): Combine pure aluminum (balance), Al-30wt%Mg master alloy, Al-20wt%Mn master alloy, and Al-10wt%TiB2 master alloy. The total mass of the above raw materials is 10 kg. The amount of the above master alloys used must ensure that the Mg content in the raw materials is 11wt%, the Mn content is 1wt%, and the TiB2 content is 0.05wt% (Ti content is 0.034wt%, and B content is 0.016wt%).

[0131] The above raw materials were placed in a vacuum furnace at 680°C for melting treatment (melting time was 35 minutes) and then kept warm and stirred. The stirring treatment lasted for 12 minutes to ensure uniform dispersion of the elements and obtain aluminum alloy melt.

[0132] The molten aluminum alloy was left to stand for 10 minutes. - The mixture was subjected to a vacuum environment of 2 Pa for 12 minutes, and then high-purity argon gas at a flow rate of 1.5 L / min was introduced to assist in dehydrogenation for 8 minutes to obtain the melt after degassing.

[0133] Step 5): Perform solid-state additive manufacturing (AFED) on the bar to obtain an aluminum alloy additive part.

[0134] The following parameters were selected for AFED additive manufacturing: feed rate of 55 mm / min; die rotation speed of 400 rpm; travel speed of 200 mm / min; and single-layer thickness of 0.8 mm. During the AFED process, the substrate and deposited layer were immersed in an ethylene glycol aqueous solution (coolant temperature -5 to 10℃) for cooling, and the AFED cooling rate was controlled at above 35℃ / s.

[0135] The maximum tensile strength of the aluminum alloy additive part prepared in Example 4 along the length, width and height directions was 527 MPa, 531 MPa and 509 MPa, respectively, the average yield strength was 342 MPa and the average elongation was 16%.

[0136] Example 5

[0137] This embodiment prepares an aluminum alloy part and an aluminum alloy additive part. The difference between this embodiment and Embodiment 1 is that steps 1) and 5) are different, while other steps and parameters are the same. Specifically, steps 1) and 5) of this embodiment are as follows:

[0138] Step 1): Combine pure aluminum (balance), Al-30wt%Mg master alloy, Al-10wt%Mn master alloy, Al-10wt%TiB2 master alloy, and Al-20wt%Zn master alloy. The total mass of the above raw materials is 10 kg. The amount of the above master alloys used must ensure that the Mg content in the raw materials is 13wt%, the Mn content is 1wt%, the TiB2 content is 0.1wt% (Ti content is 0.069wt%, B content is 0.031wt%), and the Zn content is 0.2wt%.

[0139] The above raw materials were placed in a vacuum furnace at 680°C for melting treatment (melting time was 30 minutes) and then kept warm and stirred. The stirring treatment lasted for 14 minutes to ensure uniform dispersion of the elements and obtain aluminum alloy melt.

[0140] The molten aluminum alloy was left to stand for 10 minutes. - The mixture was subjected to a vacuum environment of 2 Pa for 12 minutes, and then high-purity argon gas at a flow rate of 1.5 L / min was introduced to assist in dehydrogenation for 8 minutes to obtain the melt after degassing.

[0141] Step 5): Perform solid-state additive manufacturing (AFED) on the bar to obtain an aluminum alloy additive part.

[0142] The following parameters were selected for AFED additive manufacturing: feed rate of 60 mm / min; die rotation speed of 450 rpm; travel speed of 250 mm / min; and single-layer thickness of 0.8 mm. During the AFED process, the substrate and deposited layer were immersed in liquid nitrogen (coolant temperature < -190℃) for cooling. During liquid nitrogen cooling, a gas film was generated on the surface of the deposited layer at a relatively high temperature, which reduced the cooling efficiency. However, the low initial temperature controlled the AFED cooling rate to above 40℃ / s.

[0143] The maximum tensile strength of the aluminum alloy additive part prepared in Example 5 along the additive length direction, width direction and height direction is 541 MPa, 538 MPa and 525 MPa, respectively, the average yield strength is 358 MPa and the average elongation is 13%.

[0144] Example 6

[0145] This embodiment prepares an aluminum alloy part and an aluminum alloy additive part. The difference between this embodiment and Embodiment 1 is that step 5) is different, while the other steps and parameters are the same. Step 5) of this embodiment is as follows:

[0146] Step 5): Perform solid-state additive manufacturing (AFSD) on the bar to obtain an aluminum alloy additive part.

[0147] The following parameters were selected for AFSD additive manufacturing: feed rate of 80 mm / min; AFSD device stirring head rotation speed of 800 rpm; travel speed of 300 mm / min; and single-layer thickness of 0.8 mm. During the AFSD process, the substrate and deposited layer were immersed in cooling water (water temperature of 5-20℃) for cooling, and the AFSD cooling rate was controlled at above 30℃ / s.

[0148] The maximum tensile strength of the aluminum alloy additive part prepared in Example 6 along the additive length direction, width direction and height direction is 518MPa, 523MPa and 502MPa, respectively, the average yield strength is 331MPa and the average elongation is 15%.

[0149] Comparative Example 1

[0150] Comparative Example 1 prepared an aluminum alloy part and an aluminum alloy additive part. The difference between Comparative Example 1 and Example 1 is that step 1) is different, while the rest is the same as Example 1.

[0151] Step 1 of Comparative Example 1 is as follows:

[0152] Step 1): Combine pure aluminum (balance), Al-20wt%Mg master alloy, Al-10wt%Mn master alloy, Al-5wt%TiB2 master alloy, Al-10wt%Zr master alloy, Al-5wt%Cr master alloy, and Al-50wt%Cu master alloy. The total mass of the above raw materials is 10 kg. The amount of the above master alloys used must ensure that the content of Mg in the raw materials is 5wt%, Mn is 0.8wt%, Ti is 0.05wt%, B is 0.025wt%, Zr is 0.2wt%, Cr is 0.3wt%, and Cu is 0.1wt%.

[0153] The above raw materials are placed in a vacuum furnace at 700°C and melted. The mixture is stirred for 10 minutes to ensure uniform dispersion of the elements, thus obtaining an aluminum alloy melt.

[0154] Metallographic images of the cross-section of the cast bar obtained in Comparative Example 1 are attached. Figure 1 As shown, from Figure 1 It can be seen that the rod contains a few pores, and obvious grains can be observed with the naked eye. The grain structure diagram of the cast rod obtained by EBSD analysis is shown below. Figure 5 As shown in Figure (a), the average grain size of the cast bar with a Mg content of 5 wt% is 87 micrometers.

[0155] No obvious pores or cracks were observed in the aluminum alloy additive part obtained in Comparative Example 1. The cross-sectional metallographic image of the aluminum alloy additive part in Comparative Example 1 is shown below. Figure 3 As shown, the overall cross-section is observed to be dense and free of pores. The grain structure of the additive part in Comparative Example 1 is as follows: Figure 6 As shown, the average grain size is 2.8 micrometers. The maximum tensile strength of this additive part along the length, width, and height directions is 409 MPa, 417 MPa, and 395 MPa, respectively, with an average yield strength of 245 MPa and an average elongation of 27%. This is insufficient to meet the requirements of direct-forming strength (≥300 MPa) for aerospace load-bearing components or new energy chassis structural components. The main reason for the poor performance of the additive part prepared in Comparative Example 1 is its low Mg content and low contribution to solid solution strengthening; while in terms of microstructure, components with high Mg content have finer grain sizes.

[0156] Comparative Example 2

[0157] Comparative Example 2 prepared an aluminum alloy part and an aluminum alloy additive part. The difference between Comparative Example 2 and Example 1 is that step 1) is different, while the rest is the same as Example 1.

[0158] Step 1) of Comparative Example 2 is as follows: Pure aluminum (balance), Al-20wt%Mg master alloy, Al-10wt%Mn master alloy, Al-5wt%TiB2 master alloy, Al-10wt%Zr master alloy, Al-5wt%Cr master alloy, and Al-50wt%Cu master alloy. The total mass of the above raw materials is 10 kg. The amount of the above master alloys used must ensure that the content of Mg in the raw materials is 17wt%, Mn content is 0.8wt%, Ti content is 0.05wt%, B content is 0.025wt%, Zr content is 0.2wt%, Cr content is 0.3wt%, and Cu content is 0.1wt%.

[0159] The above raw materials are placed in a vacuum furnace at 700°C and melted. The mixture is stirred for 10 minutes to ensure uniform dispersion of the elements, thus obtaining an aluminum alloy melt.

[0160] The bar obtained in Comparative Example 2 exhibits obvious defects on both the surface and interior. Scanning electron microscopy revealed these defects. Figure 8 As shown, large-sized pores (pore size 40-150μm, density 96.2%) are present, and there is obvious enrichment of Mg and O elements near the pores, proving that due to the excessive Mg content, the reaction during the casting process is violent and the melt is difficult to stir evenly.

[0161] In the AFED process, due to the numerous pores and poor plasticity of the rod material, the flow extrusion effect is not good. It is extruded in powder form and is difficult to transform into a viscoplastic rheological state, resulting in poor formability.

[0162] Comparative Example 3

[0163] Comparative Example 3 prepared an aluminum alloy part and an aluminum alloy additive part. The difference between Comparative Example 3 and Example 1 is that step 1) is different, while the rest is the same as Example 1.

[0164] Step 1) in Comparative Example 3 is as follows: Pure aluminum (balance), Al-20wt%Mg master alloy, Al-10wt%Mn master alloy, Al-5wt%TiB2 master alloy, Al-10wt%Zr master alloy, Al-5wt%Cr master alloy, and Al-50wt%Cu master alloy. The total mass of the above raw materials is 10 kg. The amount of the above master alloys used must ensure that the content of Mg in the raw materials is 7wt%, Mn is 0.8wt%, TiB2 is 1.5wt% (Ti is 1.04wt%, B is 0.46wt%), Zr is 0.2wt%, Cr is 0.3wt%, and Cu is 0.4wt%.

[0165] The above raw materials are placed in a vacuum furnace at 700°C and melted. The mixture is stirred for 10 minutes to ensure uniform dispersion of the elements, thus obtaining an aluminum alloy melt.

[0166] In Comparative Example 3, due to the high Ti and B content in the aluminum alloy rod, coarse Al3Ti precipitates and TiB2 phases were generated in the bottom deposition layer under repeated thermal cycling during deposition. After deposition, the microstructure and properties of the material were uneven in different regions, the material had low plasticity, and the forming process was unstable.

[0167] Comparative Example 4

[0168] Comparative Example 4 prepared an aluminum alloy part and an aluminum alloy additive part. The difference between Comparative Example 4 and Example 1 is that step 5) is different, while the rest is the same as Example 1.

[0169] Step 5 in Comparative Example 4 is as follows: The bar is subjected to solid-state additive manufacturing (AFED) to obtain an aluminum alloy additive part.

[0170] The water near the substrate and deposition layer was cleared, and the following parameters were selected for direct AFED additive manufacturing at room temperature: feed rate of 50 mm / min; die speed of 600 rpm; travel speed of 150 mm / min; and single-layer thickness of 0.8 mm.

[0171] The peak temperature of AFED was measured to be 437℃, and the cooling rate was 12℃ / min.

[0172] The additive parts obtained in Comparative Example 4 have maximum tensile strengths of 382 MPa, 375 MPa, and 373 MPa along the length, width, and height directions, respectively, an average yield strength of 217 MPa, and an average elongation of 25%. The parts contain a large number of Al3Mg2 particles, some of which are significantly segregated near the grain boundaries. The additional Mg elements have not been effectively dissolved. At the same time, the dislocation density is low at the higher deposition peak temperature. Furthermore, the yield strength of the parts obtained in Comparative Example 4 is significantly different from that of the parts obtained under water-cooling conditions.

[0173] Comparative Example 5

[0174] Comparative Example 5 prepared an aluminum alloy part and an aluminum alloy additive part. The difference between Comparative Example 5 and Example 1 is that step 5) is different, while the rest is the same as Example 1.

[0175] Step 5 in Comparative Example 4 is as follows: The bar is subjected to solid-state additive manufacturing (AFED) to obtain an aluminum alloy additive part.

[0176] In the AFED process, the substrate and the deposited layer are immersed in water for cooling; and the following parameters are selected for AFED additive manufacturing: feed rate is 60 mm / min; die speed is 200 rpm; travel speed is 500 mm / min; and single layer thickness is 0.8 mm.

[0177] In Comparative Example 5, due to the excessively low mold rotation speed, the cast-state base material could not be softened, resulting in an extruded material state that differed from the plastic rheological state in other embodiments, being extruded as a powder. Because the substrate was submerged in water, the powder, carried by the water flow, could not remain at the intended deposition site and dispersed everywhere, preventing the deposition of effective components for analysis.

[0178] Comparative Example 6

[0179] Comparative Example 6 prepared an aluminum alloy part and an aluminum alloy additive part. The difference between Comparative Example 6 and Example 6 is that step 5) is different, while the rest is the same as Example 1.

[0180] Step 5) in Comparative Example 6 is as follows: The rod is subjected to solid-state additive manufacturing (AFSD) to obtain an aluminum alloy additive part. During the AFSD process, the substrate and deposited layer are immersed in an ethylene glycol aqueous solution (coolant temperature -5 to 10°C) for cooling; and the following parameters are selected for AFSD additive manufacturing: feed rate of 180 mm / min; stirring head rotation speed of the AFSD device of 1200 rpm; travel speed of 900 mm / min; and single-layer thickness of 0.8 mm.

[0181] Under high rotation speed, the raw material is effectively softened. However, due to the small softened area, the deposition process travels too fast, making it difficult to complete continuous additive manufacturing. As a result, the deposited components are poorly formed and cannot be effectively added.

[0182] In this invention, compared to traditional commercial 2xxx, 5xxx, 6xxx, and 7xxx series aluminum alloys, the high-magnesium-content cast aluminum-magnesium-based aluminum alloy prepared by this invention exhibits significantly improved strength and yield strength after AFED deposition, while maintaining good elongation. The casting homogenization process significantly reduces the manufacturing cost of the base material. Simultaneously, this invention achieves innovative coupling of process and materials: using low-cost cast homogenized base material for direct AFED forming, and by matching process parameters with dynamic recrystallization behavior, porosity in the cast base material is eliminated. Furthermore, it achieves synergistic control of grain refinement (average grain size <3μm, 97.0% refinement compared to the base material), high strength (tensile strength >500MPa, yield strength >300MPa), and high elongation (>20%), ultimately obtaining a heat-free AFED additive component with a dense and uniform microstructure and excellent mechanical properties.

[0183] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. An aluminum alloy part, characterized in that, The aluminum alloy part is used as a raw material for solid-state additive manufacturing processes; wherein, by weight fraction, the aluminum alloy part comprises the following chemical composition: Mg: 7~15wt%, Mn: 0~1.4wt%, reinforcing element: 0~5wt%, impurity element: 0~0.5wt%, balance Al; wherein the reinforcing element includes at least one of Ti, B, Zn, Cr, Zr, Sc, and Cu.

2. The aluminum alloy part according to claim 1, characterized in that, In the aluminum alloy parts: The content of Mn is 0~1.4wt%; the content of Ti is 0~0.2wt%; the content of B is 0~0.1wt%; the content of Zn is 0~0.8wt%; the content of Cr is 0~1.0wt%; the content of Zr is 0~0.5wt%; the content of Sc is 0~1wt%; and the content of Cu is 0~0.4wt%.

3. The aluminum alloy part according to claim 1, characterized in that, The aluminum alloy part is an aluminum alloy rod.

4. The aluminum alloy part according to claim 3, characterized in that, The cross-sectional area of ​​the aluminum alloy rod is 9~900mm². 2 Length ≥ 120mm.

5. The aluminum alloy part according to claim 3, characterized in that, The aluminum alloy rod is a cast rod or an extruded rod; The cast rod has a density ≥96%, a pore size ≤500μm, and a grain size of 20~500μm; The extruded bar has a density of ≥98%, a pore size of ≤300μm, and a grain size of 20~300μm.

6. The method for preparing the aluminum alloy part according to any one of claims 1-5, characterized in that, It includes the following steps: Smelting steps: The raw materials are melted and then kept at a constant temperature and stirred to obtain an aluminum alloy melt; Casting and demolding steps: The aluminum alloy melt is cast and demolded to obtain an ingot; The ingot can be used directly as an aluminum alloy part; or the ingot can be machined or hot-extruded to obtain an aluminum alloy part.

7. The method for preparing aluminum alloy parts according to claim 6, characterized in that, If the ingot is used directly as an aluminum alloy part, then the aluminum alloy part is a cast bar stock; If the ingot is machined and then used as an aluminum alloy part, the aluminum alloy part is a cast bar stock. If the ingot is used as an aluminum alloy after hot extrusion, then the aluminum alloy part is a hot-extruded bar.

8. The method for preparing aluminum alloy parts according to claim 6, characterized in that, In the smelting step, The raw materials include: aluminum-magnesium alloy and aluminum.

9. The method for preparing aluminum alloy parts according to claim 8, characterized in that, In the smelting step, the raw materials also include at least one intermediate alloy selected from aluminum-manganese alloy, aluminum-titanium diboride alloy, aluminum-zinc alloy, aluminum-chromium alloy, aluminum-zirconium alloy, aluminum-scandium alloy, and aluminum-copper alloy.

10. The method for preparing aluminum alloy parts according to claim 8 or 9, characterized in that, In the smelting step, the raw materials include aluminum-magnesium alloy with a magnesium content of 20-50 wt% and aluminum.

11. The method for preparing aluminum alloy parts according to claim 10, characterized in that, In the smelting step, the raw materials further include: At least one intermediate alloy selected from the following: aluminum-manganese alloy with a manganese content of 10-25 wt%, aluminum-titanium diboride alloy with a TiB2 content of 5-10 wt%, aluminum-zinc alloy with a zinc content of 5-50 wt%, aluminum-chromium alloy with a chromium content of 5-20 wt%, aluminum-zirconium alloy with a zirconium content of 5-15 wt%, aluminum-scandium alloy with a scandium content of 2-10 wt%, and aluminum-copper alloy with a copper content of 20-50 wt%.

12. The method for preparing aluminum alloy parts according to claim 6, characterized in that, In the melting step: the melting temperature is 680~750℃; the melting time is 30~50 minutes.

13. The method for preparing aluminum alloy parts according to claim 6, characterized in that, In the smelting step: the temperature of the heat preservation and stirring treatment is 680~750℃, and the heat preservation and stirring treatment time is 10~20 minutes.

14. The method for preparing aluminum alloy parts according to claim 6, characterized in that, When the magnesium content of the raw material in the smelting step is ≥10wt%, an venting step is performed after the smelting step and before the casting and demolding steps to control the density of the ingot.

15. The method for preparing aluminum alloy parts according to claim 14, characterized in that, The exhaust step includes: in ≤10 - Under a vacuum environment of 2Pa, the aluminum alloy melt is left to stand for 10-15 minutes. The dissolved hydrogen in the melt is removed by using the vacuum negative pressure. Argon gas is then introduced and continued for 5-10 minutes.

16. The method for preparing aluminum alloy parts according to claim 6, characterized in that, In the pouring and demolding steps: Before casting, the following pretreatment is required: adjust the temperature of the aluminum alloy melt to the casting temperature, wherein the casting temperature is 680~700℃; preheat the casting mold to 200~250℃, and spray a release agent inside the mold.

17. The method for preparing aluminum alloy parts according to claim 6, characterized in that, After the ingot cools to below 150°C, it is demolded.

18. A solid-phase additive manufacturing method for aluminum alloy additive parts, characterized in that, It includes the following steps: The aluminum alloy part according to any one of claims 1-5 is subjected to solid-state additive manufacturing (AFED) to obtain an aluminum alloy additive part; or The aluminum alloy part according to any one of claims 1-5 is subjected to solid-state additive manufacturing (AFSD) to obtain an aluminum alloy additive part.

19. The solid-state additive manufacturing method for aluminum alloy additive parts according to claim 18, characterized in that, During the solid-phase additive manufacturing process of AFED: Using the aluminum alloy part as described in any one of claims 1-5 as raw material, under the pressure of the feeding mechanism, the raw material is fed to the rotating friction extrusion deposition die, and rubs against the inner surface of the friction extrusion deposition die, so that the raw material near the extrusion port of the friction extrusion deposition die reaches a viscoplastic rheological state due to friction and deformation heat; the softened material is pushed axially under the action of the feeding mechanism, extruded from the extrusion port and deposited on the surface of the substrate, and moved laterally along the predetermined additive path and repeated multiple times to obtain an aluminum alloy additive part; The feeding speed is 25~180mm / min; the rotation speed of the friction extrusion deposition mold is 300~1000rpm; the travel speed is 50~1000mm / min; and the thickness of a single deposition layer is 0.5~2mm.

20. The solid-phase additive manufacturing method for aluminum alloy additive parts according to claim 19, characterized in that, The feeding speed is 30~150mm / min, the rotation speed of the friction extrusion deposition mold is 400~800rpm, the travel speed is 200~600mm / min, and the thickness of a single deposition layer is 0.8~1.6mm.

21. The solid-state additive manufacturing method for aluminum alloy additive parts according to claim 18, characterized in that, During the solid-phase additive manufacturing process of AFSD: Using the aluminum alloy part described in any one of claims 1-5 as raw material, the raw material rotates together with the stirring head of the AFSD device. Under the action of axial force, the raw material is fed and reaches a viscoplastic rheological state after the end of the raw material rubs against the substrate or the deposited layer. The material softened at the end of the raw material is pushed along the axial direction and deposited on the surface of the substrate. It moves laterally along the predetermined additive path and repeats multiple times to obtain an aluminum alloy additive part. The feeding speed is 25~120mm / min; the rotation speed of the stirring head of the AFSD device is 500~1200rpm; the travel speed is 50~800mm / min; and the thickness of a single deposition layer is 0.5~2mm.

22. The solid-phase additive manufacturing method for aluminum alloy additive parts according to claim 21, characterized in that, The feed rate is 30~80 mm / min; the rotation speed of the stirring head of the AFSD device is 500~1000 rpm; the travel speed is 100~500 mm / min; and the thickness of a single-layer deposition layer is 0.8~1.6 mm.

23. The solid-state additive manufacturing method for aluminum alloy additive parts according to claim 18, characterized in that, During the solid-phase additive manufacturing process of AFED or AFSD: the substrate and the deposited layer are cooled by immersing them in a coolant to control the cooling rate of AFED or AFSD to above 30°C / s.

24. An aluminum alloy additive manufacturing part, characterized in that, The aluminum alloy additive part is prepared by the solid-phase additive manufacturing method of the aluminum alloy additive part according to any one of claims 18-23; wherein, the yield strength of the aluminum alloy additive part is ≥300MPa.

25. The aluminum alloy additive manufacturing part according to claim 24, characterized in that, The matrix structure of the aluminum alloy additive part is a supersaturated solid solution; the grain size of the aluminum alloy additive part is 0.8~3.5μm.

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