High-strength and high-conductivity Al-Mg-Si-Ce alloy wire, multi-stage regulation preparation method and application thereof

Abstract

The application discloses a kind of high-strength high-conductivity Al-Mg-Si-Ce alloy wire and its multistage adjustment control preparation method and application, belong to aluminum alloy material processing technical field.The application is added in Al-Mg-Si series alloy by economical and environmental rare earth element Ce, and is combined with the multistage compound process of '' spin forging → pre-aging → first-stage medium-temperature deformation → second-stage low-temperature deformation → ladder aging'', realizes the accurate regulation and control of β '' strengthening phase and β'phase and uniform organization construction in alloy wire, and finally alloy wire tensile strength is 309.4~326.5MPa, conductivity is 54.6~62.1%IACS, can simultaneously solve the technical bottleneck that strength and conductivity contradiction is prominent in traditional process, precipitated phase control is extensive, and organization uniformity is insufficient.The application does not need to add expensive rare alloy element, can significantly reduce production cost, and can improve alloy performance stability and long-term service reliability by optimizing process.

Description

Technical Field

[0001] This invention relates to a high-strength, high-conductivity Al-Mg-Si-Ce alloy wire, its multi-level controlled preparation method and application, belonging to the field of aluminum alloy material processing technology. Background Technology

[0002] High-strength and high-conductivity Al-Mg-Si alloys are ideal materials for overhead power transmission lines, rail transit contact networks and other fields. Their core performance depends on the large number of nanoscale β'' strengthening phases that are dispersed after heat treatment.

[0003] While the existing invention patent 202411486020.4, "A High-Strength, High-Conductivity Aluminum Alloy Wire and Its Preparation Method and Application," achieves a synergistic improvement in strength and conductivity, the addition of expensive and toxic elements such as Be and Ni not only increases raw material costs and environmental health risks but also limits the material's application prospects in sustainability-oriented industrial fields. More importantly, its technical approach fails to achieve precise control over the spatial distribution of the alloy's core microstructure—dislocations and precipitates—resulting in mostly random precipitate distributions that cause significant electron scattering, thus failing to fully realize the potential for balancing strength and conductivity. Summary of the Invention

[0004] The purpose of this invention is to provide a high-strength, high-conductivity Al-Mg-Si-Ce alloy wire, its multi-level controlled preparation method, and its application. The method involves adding the economical and environmentally friendly rare earth element Ce (which refines grains and reacts with Fe and Si impurities, reducing lattice distortion in the Al solid solution and improving conductivity). A multi-level composite process of "rotary forging → pre-aging → first-stage medium-temperature deformation → second-stage low-temperature deformation → step-aging" is employed to directionally construct a unique microstructure in the alloy where dislocations and precipitates are regularly arranged axially, thereby simultaneously improving the alloy's strength and conductivity. The high-strength, high-conductivity Al-Mg-Si-Ce alloy wire achieves a synergistic improvement in both strength and conductivity. Furthermore, this invention provides applications of the high-strength, high-conductivity Al-Mg-Si-Ce alloy wire in lightweight, long-service-life materials.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, a high-strength, high-conductivity Al-Mg-Si-Ce alloy wire is provided, wherein the alloy wire has dislocation lines regularly arranged along the axial direction, and the β′ phase and the β″ strengthening phase are regularly arranged along the dislocation lines, wherein the β′ phase is β′-Mg2Si and the β″ strengthening phase is β″-Mg2Si.

[0007] In the above technical solution, the β′ phase and the β″ strengthening phase are regularly arranged along the dislocation line to form an ordered "precipitate-dislocation chain" composite structure. The "precipitate-dislocation chain" composite structure causes solute atoms to aggregate in the regularly arranged precipitate phase, and the lattice distortion is localized and ordered, thereby significantly improving conductivity while maintaining strength.

[0008] Furthermore, the β'' reinforcing phase has a particle size of 2.1-3.8 nm, a length of 27.4-39.7 nm, and an areal density of 4.5 × 10⁻⁶. -3 -5.8×10 -3 / nm 2 The β' phase has a particle size of 11.8–20.3 nm, a length of 43.4–52.3 nm, and an areal density of 2.2 × 10⁻⁶. -3 -2.8×10 -3 / nm 2 .

[0009] Furthermore, the alloy wire has a tensile strength of 309.4~326.5MPa and a conductivity of 54.6~62.1%IACS.

[0010] Furthermore, the alloy contains 0.15 wt.% to 0.25 wt.%, 0.25 wt.% to 0.40 wt.%, 0.20 wt.% to 0.40 wt.%, and the balance is Al and unavoidable impurities.

[0011] Preferably, the aluminum alloy contains 0.2 wt.% Mg, 0.35 wt.% Si, and 0.3 wt.% Ce, with the balance being Al and unavoidable impurities. Since the aluminum alloy contains no other expensive or harmful alloying elements, it is lower in cost, more environmentally friendly, and easier to recycle, perfectly meeting the core demand for low-cost, highly environmentally friendly materials in the cost-effective industrial profile sector.

[0012] In a second aspect, a multi-level controlled preparation method for the high-strength, high-conductivity Al-Mg-Si-Ce alloy wire as described in any one of the first aspects is provided, comprising the following steps:

[0013] S01, Melting and casting: Obtaining aluminum alloy ingots;

[0014] S02, Homogenization treatment: The prepared aluminum alloy ingot is heated to 550-570℃ at a rate of 4~6℃ / min at room temperature and held for 4-8 hours; after the holding period, the alloy is immediately water quenched to 140~160℃ at a cooling rate of 190~210℃ / s, and then air cooled to room temperature.

[0015] S03, Hot extrusion billet: The homogenized ingot is hot extruded at 500-520℃ with an extrusion ratio of 14-18 to obtain extruded bars.

[0016] S04, Rotary Forging: The extruded bar is cooled to room temperature and then rotary forged at room temperature to reduce its diameter by 40% to 60% in order to form dislocations that are oriented along the axial direction, thus obtaining a rotary forged bar.

[0017] S05, Multi-stage deformation heat treatment:

[0018] S05a, Pre-aging treatment: The forged bar obtained from S04 is heated to 175-185℃ at a rate of 4~6℃ / min at room temperature and held for 1-2 hours. Then, the alloy is immediately water-quenched to 90~110℃ at a cooling rate of 190~210℃ / s, and then air-cooled to room temperature.

[0019] S05b, Level 1 Medium Temperature Drawing: The bar obtained from S05a is drawn in multiple passes at an environment of 200-250℃, with a total deformation of 40-60%, to obtain wire.

[0020] S05c, Secondary Low Temperature Drawing: The wire after the primary medium temperature drawing is drawn again at room temperature, with a total deformation of 80-90%;

[0021] S05d, stepped aging treatment:

[0022] S05d1, Low-temperature peak aging stage: The drawn wire is heated to 160-170℃ at a rate of 4~6℃ / min and held for 4-8 hours;

[0023] S05d2, High-temperature stabilization stage: The filament obtained from S05d1 is heated to 215-225℃ at a rate of 4~6℃ / min and held at that temperature for 0.5-1.5 hours, and then air-cooled to room temperature to obtain the final product.

[0024] In the above technical solution, firstly, rotary forging is used to distribute dislocations in a certain direction, providing a nucleation "skeleton" for subsequent precipitates. During the pre-aging stage, GP regions or fine β'' phase nuclei are formed, uniformly distributed along the dislocations, serving as a "benchmark" for subsequent deformation. A first-stage medium-temperature drawing introduces polygonal dislocation structures, forming stable subgrain boundaries as conductive channels. A further second-stage low-temperature drawing introduces extremely high-density dislocations within the formed subgrains, providing nucleation points for the subsequent ultra-high-density precipitation of the β'' phase. Low-temperature aging precipitates a large number of dispersed, fine β'' strengthening phases at the introduced high-density dislocations, achieving peak strength. High-temperature stabilization transforms some of the fine β'' phases into coarser β' phases, promoting the full precipitation of solute atoms on the grain boundaries, significantly reducing lattice distortion, greatly improving conductivity, and stabilizing the microstructure to form a uniform microstructure. This uniform microstructure has a stable substructure composed of subgrain boundaries and high dislocation density, enabling precise control of the β'' strengthening phase and β' phase and the construction of a uniform microstructure.

[0025] Furthermore, in S01, the casting method for aluminum alloy ingots is as follows: raw materials are selected according to their composition and dried in an oven at at least 200°C; the crucible is preheated to 400-500°C, industrial pure aluminum and Al-Si master alloy are added, the temperature is raised to 750-770°C, and after the furnace charge is completely melted, it is held for 30-60 minutes; then the melt is cooled to 730-750°C and refined, using C2Cl6 as the refining agent, with the amount of refining agent added being 0.6-0.8% of the total mass of the aluminum melt; slag is skimmed off, and the melt is held at the temperature for 10-20 minutes; Al-8.8wt%Ce, Al-3B master alloy and pure magnesium ingots are pressed in respectively, and after the settling is completed, the melt is heated to 720-730°C and poured into a cylindrical mold preheated to 200-220°C to finally obtain an Al-Mg-Si-Ce alloy ingot.

[0026] Furthermore, in S05, both the pre-aging treatment and the step aging treatment are carried out under nitrogen protection.

[0027] Furthermore, in S04, the diameter reduction during rotary forging is 50%.

[0028] After step S04, the radial compression and axial extension of rotary forging cause dislocations to align along the axis, forming a directional dislocation structure. This provides an ideal "skeleton" for the precipitation of β' and β'' phases during subsequent aging, allowing them to be distributed in an orderly manner along the dislocations. After step S05a, by forming GP regions that are coherent with the matrix and cannot be cut by dislocations, and β'' phase cores, a uniform barrier network at the nanoscale is established inside the grain. This serves as a "benchmark" for precisely controlling subsequent plastic deformation and final precipitation behavior.

[0029] Following steps S05b and S05c, a dynamic recovery mechanism guides dislocation recombination into stable subgrain boundaries, constructing highly efficient conductive channels. Within the formed subgrains, further deformation introduces high-density and ordered secondary dislocations, serving as ideal nucleation sites and promoting the ultra-high density precipitation of the β'' phase during subsequent aging treatment.

[0030] Following steps S05d1 and S05d2, low-temperature peak aging induces a large number of dispersed nanoscale β'' phases at the high-density ordered dislocations introduced in step S05c, thereby pushing the material strength to its peak value. In the high-temperature stabilization stage, by coarsening some of the β'' phase into β' phase, an ordered "precipitate-dislocation chain" composite structure is formed. This significantly reduces lattice distortion, achieving both microstructure stabilization and a substantial increase in material conductivity.

[0031] This invention incorporates the economical and environmentally friendly rare earth element Ce into Al-Mg-Si alloys. It leverages the inherent flexibility of Al-Mg-Si-Ce alloys under plastic deformation and the evolution of their internal microstructure during subsequent aging treatment to enhance strength and conductivity. Strength enhancement: ① The addition of Ce provides grain refinement and strengthening; ② Under forging and drawing conditions, the alloy develops extremely high dislocation density and a large number of second-phase precipitates, utilizing strong dislocation entanglement and pinning to impede movement, significantly improving material strength; ③ After aging, β' and β'' strengthening phases precipitate, contributing to the increased strength. Conductivity enhancement: On one hand, Ce reacts with Fe and Si impurities to form compounds, reducing lattice distortion in the Al solid solution and improving conductivity. On the other hand, after aging treatment, a large number of solute atoms (Mg, Si) detach from the matrix, forming β'' and β' phases, purifying the matrix and thus improving conductivity. By utilizing the process of "rotary forging (dislocation orientation distribution) → pre-aging (initial β'' core) → intermediate temperature deformation (subgrain boundary strengthening + providing nucleation sites) → low temperature large deformation (dislocation strengthening + providing ultra-high density nucleation sites) → step aging (ultra-high density precipitation strengthening + microstructure stabilization)," the effect of simultaneous enhancement of strength and conductivity is achieved.

[0032] The beneficial effects of adopting the above technical solution are: the present invention provides a method for preparing high-strength and high-conductivity Al-Mg-Si-Ce alloy wires that can be prepared on a large scale, with simple process and controllable cost, and can achieve optimization of the comprehensive performance of materials without relying on complex and expensive alloying elements or extreme processing conditions.

[0033] This invention first creates an axially regularly arranged array of dislocations in the material through rotary forging, providing a pre-oriented nucleation topology framework for subsequent precipitates. Pre-aging treatment forms uniform GP regions or β'' phase nuclei with regular dislocation distribution. Subsequently, a first-stage medium-temperature drawing, under dynamic recovery, reorganizes some dislocations into stable subgrain boundaries aligned with the axial direction, constructing highly efficient conductive channels. A second-stage low-temperature drawing further introduces high-density and ordered secondary dislocations within this framework. Finally, a stepped aging treatment causes the precipitates (β'' and β' phases) to preferentially and strictly precipitate along the aforementioned regularly arranged dislocation lines, forming an ordered "precipitate-dislocation chain" composite structure. This composite structure is key to achieving high performance: the ordered distribution of the precipitates provides continuous strengthening; simultaneously, the lattice distortion is localized and ordered, greatly reducing electron wave scattering. Combined with the purified matrix and regular subgrain boundaries, this constitutes a highly efficient electronic pathway, thereby significantly improving conductivity while maintaining high strength. The final alloy wire has a tensile strength of 309.4~326.5MPa and a conductivity of 54.6~62.1%IACS.

[0034] Thirdly, the application of the high-strength, high-conductivity Al-Mg-Si-Ce alloy wire described in any one of the first aspects in materials that combine lightweight and ultra-long service life is provided.

[0035] Furthermore, materials with lightweight and ultra-long service life include power transmission and distribution materials, rail transit materials, and aerospace materials; power transmission and distribution materials include overhead conductors, electromagnetic wires, winding wires, cable cores, and busbars; rail transit materials and aerospace materials both include overhead transmission conductors, rail transit contact networks, high-voltage transmission lines, and electronic component leads.

[0036] Compared with the prior art, the beneficial effects of the present invention are:

[0037] This invention draws on the principles of rotary forging and drawing processes to orient dislocations and introduce plastic deformation energy storage, and aging treatment to promote microstructure optimization. It achieves precise control of the β″ strengthening phase and β′ phase and uniform microstructure construction, without the need for complex hot working equipment. The process is easy to operate and has low energy consumption.

[0038] This invention significantly improves the overall performance of Al-Mg-Si-Ce alloys by controlling the dislocation, β′, and β″ strengthening phases within the alloy: On the one hand, by introducing the rare earth element Ce combined with high-strain rotary forging and drawing processes, the alloy achieves grain refinement and dislocation strengthening. The grain boundaries and high-density dislocations hinder dislocation movement, resulting in a significant improvement in mechanical properties, with a tensile strength of 309.4~326.5 MPa. On the other hand, the addition of Ce effectively reduces the impurity content in the aluminum solid solution, mitigating lattice distortion. Furthermore, after aging treatment, a large number of solute atoms (Mg, Si) detach from the matrix, forming β′ and β″ phases distributed in an orderly manner along the dislocations. This precipitation strengthens the alloy while purifying the matrix, resulting in a significant increase in conductivity, with a conductivity of 54.6~62.1% IACS.

[0039] This invention achieves precise control and uniform microstructure construction of the β″ strengthening phase and β′ phase in alloy conductors by adding the economical and environmentally friendly rare earth element Ce to Al-Mg-Si alloys and combining it with a multi-stage composite process of "rotary forging → pre-aging → first-stage medium-temperature deformation → second-stage low-temperature deformation → stepped aging". The final alloy conductor has a tensile strength of 309.4~326.5MPa and a conductivity of 54.6~62.1%IACS. This simultaneously solves the technical bottlenecks of traditional processes, such as the prominent contradiction between strength and conductivity, coarse control of precipitates, and insufficient microstructure uniformity. The experimental design of this scheme is simple and easy to implement, requiring no expensive rare alloying elements. It significantly reduces raw material and production costs while improving alloy performance stability and long-term service reliability through process optimization, reducing performance loss and resource waste during production. It perfectly meets the core needs of power transmission, electronics industry, and other fields for low-cost, environmentally friendly, and high-performance conductive materials, possessing significant industrial application value and suitable for key conductive load-bearing components such as high-voltage transmission lines and electronic component leads. Attached Figure Description

[0040] Figure 1 This is a diagram showing the dimensions and shape of the tensile specimen in an embodiment of the present invention;

[0041] Figure 2 This is a flowchart of the multi-level regulation preparation method in an embodiment of the present invention;

[0042] Figure 3 Figure 1 shows the microstructure of the sample after rotary forging, where dislocations are oriented and precipitates are distributed along the dislocations. Figure 2 shows that after aging treatment, a large number of solute atoms (Mg, Si) are detached from the matrix to form β' and β'' phases that are distributed in an orderly manner along the dislocations. Detailed Implementation

[0043] The following description, in conjunction with the accompanying drawings and embodiments of the present invention, will further clarify the objectives, technical solutions, and advantages of the present invention. The specific embodiments described are merely illustrative and are not intended to limit the scope of the invention.

[0044] Example 1:

[0045] High-strength, high-conductivity Al-Mg-Si-Ce alloy wire with a diameter of 3 mm was prepared. After rotary forging, an axially regularly arranged array of dislocations was created, providing a pre-oriented nucleation topological framework for subsequent precipitates. Pre-aging treatment was then used to form uniform GP regions or β″ phase nuclei distributed along the dislocations. Subsequently, a first-stage medium-temperature drawing, under dynamic recovery, reorganized some dislocations into stable subgrain boundaries aligned with the axial direction, constructing highly efficient conductive channels. A second-stage low-temperature drawing further introduced high-density and ordered secondary dislocations within this framework. Finally, a stepped aging treatment ensured that the precipitates (β″ and β' phases) preferentially and strictly precipitated along the aforementioned regularly arranged dislocation lines, forming an ordered "precipitate-dislocation chain" composite structure.

[0046] The aluminum alloy is an Al-Mg-Si-Ce alloy, wherein the Mg content is 0.2 wt.%, the Si content is 0.35 wt.%, the Ce content is 0.3 wt.%, and the balance is Al and unavoidable impurities.

[0047] like Figure 2 As shown, a multi-level controlled preparation method for high-strength, high-conductivity Al-Mg-Si-Ce alloy wires is as follows:

[0048] (1) Casting aluminum alloy: Select raw materials according to composition content, preheat crucible to 450°C, add industrial pure aluminum and Al-Si master alloy, heat to 760°C and hold for 30 min; then cool the melt to 730°C, refine with C2Cl6 refining agent, the amount of refining agent added is 0.6% of the total mass of aluminum melt, hold for 10 min; press in Al-8.8wt%Ce, Al-3B master alloy and pure magnesium ingot respectively; after holding, heat the melt to 725°C and pour it into a columnar mold preheated to 200°C, finally obtain Al-Mg-Si-Ce alloy ingot;

[0049] (2) Homogenization treatment: The prepared aluminum alloy ingot is heated to 560°C at a rate of 5°C / min at room temperature and held for 6 hours. After the holding period, the alloy is immediately water-quenched to 150°C at a cooling rate of 200°C / s, and then air-cooled to room temperature.

[0050] (3) Hot extrusion billet: The homogenized ingot is hot extruded at 510℃ with an extrusion ratio of 16 to obtain extruded bar stock;

[0051] (4) Rotary forging: The extruded bar is cooled to room temperature and then rotary forged at room temperature to reduce its diameter by 50% to form a dislocation array oriented along the axial direction, thus obtaining a rotary forged bar.

[0052] (5) Pre-aging treatment: The forged bar obtained in step (4) is heated to 180°C at a rate of 5°C / min and held for 1.5 hours at room temperature. Then the alloy is immediately quenched to 100°C at a cooling rate of 200°C / s and then air-cooled to room temperature.

[0053] (6) First-stage medium-temperature drawing: The bar obtained in step (5) is drawn in multiple passes at 220°C, with a total deformation of 50%, to obtain wire.

[0054] (7) Secondary low-temperature drawing: The wire after the first drawing is drawn again at room temperature (20-30℃) and the total deformation is 80% (relative to the size after step (6)).

[0055] (8) Low temperature peak aging stage: The drawn wire is heated to 160℃ at a rate of 5℃ / min and kept at that temperature for 4 hours;

[0056] (9) High temperature stabilization stage: The filament obtained in step (8) is heated to 215°C at a rate of 5°C / min and kept at that temperature for 0.5 hours, and then air-cooled to room temperature to obtain the finished product.

[0057] The high-strength, high-conductivity Al-Mg-Si-Ce alloy wire described in this embodiment combines lightweight and ultra-long service life, demonstrating significant economic and environmentally friendly characteristics.

[0058] Materials combining lightweight design and ultra-long service life are used in power transmission and distribution, rail transportation, and aerospace. In power transmission and distribution, this includes overhead conductors, electromagnetic wires / winding wires, cable cores, and busbars. The β″ phase in the sample microstructure has a grain size of approximately 2.1 nm, a length of approximately 27.4 nm, and an areal density of 5.8 × 10⁻⁶. -3 / nm 2 The β' phase has a particle size of approximately 11.8 nm, a length of approximately 43.4 nm, and an areal density of 2.2 × 10⁻⁶. -3 / nm 2 The tensile strength is 326.5 MPa, and the conductivity is 62.1% IACS.

[0059] like Figure 3 As shown in Figure (a), the dislocations in the sample are oriented and the precipitated phases are distributed along the dislocations after the sample is forged. Figure (b) shows that after the sample is aged, a large number of solute atoms (Mg, Si) are detached from the matrix and form β' and β'' phases that are distributed in an orderly manner along the dislocations.

[0060] Example 2:

[0061] High-strength, high-conductivity Al-Mg-Si-Ce alloy wire with a diameter of 3 mm was prepared. After rotary forging, an axially regularly arranged array of dislocations was created, providing a pre-oriented nucleation topological framework for subsequent precipitates. Pre-aging treatment was then used to form uniform GP regions or β″ phase nuclei distributed along the dislocations. Subsequently, a first-stage medium-temperature drawing, under dynamic recovery, reorganized some dislocations into stable subgrain boundaries aligned with the axial direction, constructing highly efficient conductive channels. A second-stage low-temperature drawing further introduced high-density and ordered secondary dislocations within this framework. Finally, a stepped aging treatment ensured that the precipitates (β″ and β' phases) preferentially and strictly precipitated along the aforementioned regularly arranged dislocation lines, forming an ordered "precipitate-dislocation chain" composite structure.

[0062] The aluminum alloy is an Al-Mg-Si-Ce alloy, wherein the Mg content is 0.15 wt.%, the Si content is 0.25 wt.%, the Ce content is 0.2 wt.%, and the balance is Al and unavoidable impurities.

[0063] A multi-stage controlled preparation method for high-strength, high-conductivity Al-Mg-Si-Ce alloy wires is as follows:

[0064] (1) Casting aluminum alloy: Select raw materials according to composition content, preheat crucible to 400℃, add industrial pure aluminum and Al-Si master alloy, heat to 750℃ and hold for 60min; then cool the melt to 750℃, refine with C2Cl6 refining agent, the amount of refining agent added is 0.7% of the total mass of aluminum melt, hold for 20min; press in Al-8.8wt%Ce, Al-3B master alloy and pure magnesium ingot respectively; after holding, heat the melt to 720℃ and pour it into a columnar mold preheated to 220℃, finally obtain Al-Mg-Si-Ce alloy ingot;

[0065] (2) Homogenization treatment: The prepared aluminum alloy ingot is heated to 550°C at a rate of 4°C / min at room temperature and held for 4 hours. After the holding period, the alloy is immediately quenched to 140°C at a cooling rate of 190°C / s and then air-cooled to room temperature.

[0066] (3) Hot extrusion billet: The homogenized ingot is hot extruded at 500°C with an extrusion ratio of 14 to obtain extruded bar stock;

[0067] (4) Rotary forging: The extruded bar is cooled to room temperature and then rotary forged at room temperature to reduce its diameter by 40% to form a dislocation array oriented along the axial direction, thus obtaining a rotary forged bar.

[0068] (5) Pre-aging treatment: The forged bar obtained in step (4) is heated to 175°C at a rate of 4°C / min and held for 1 hour at room temperature. Then the alloy is immediately quenched to 90°C at a cooling rate of 190°C / s and then air-cooled to room temperature.

[0069] (6) First-stage medium-temperature drawing: The bar obtained in step (5) is drawn in multiple passes at 200℃, with a total deformation of 40%, to obtain wire.

[0070] (7) Secondary low temperature drawing: The wire after the first drawing is drawn at room temperature (20°C) and the total deformation is 85% (relative to the size after step (6)).

[0071] (8) Low temperature peak aging stage: The drawn wire is heated to 165℃ at a rate of 4℃ / min and kept at that temperature for 6 hours;

[0072] (9) High temperature stabilization stage: The filament obtained in step (8) is heated to 220°C at a rate of 4°C / min and kept at that temperature for 1 hour, and then air-cooled to room temperature to obtain the finished product.

[0073] The β″ phase in the sample microstructure has a grain size of approximately 2.7 nm, a length of approximately 34.4 nm, and an areal density of 5.1 × 10⁻⁶. -3 / nm 2 The β' phase has a particle size of approximately 14.8 nm, a length of approximately 47.4 nm, and an areal density of 2.8 × 10⁻⁶. -3 / nm 2 The tensile strength is 316.8 MPa, and the conductivity is 59.5% IACS.

[0074] Example 3:

[0075] High-strength, high-conductivity Al-Mg-Si-Ce alloy wire with a diameter of 3 mm was prepared. After rotary forging, an axially regularly arranged array of dislocations was created, providing a pre-oriented nucleation topological framework for subsequent precipitates. Pre-aging treatment was then used to form uniform GP regions or β″ phase nuclei distributed along the dislocations. Subsequently, a first-stage medium-temperature drawing, under dynamic recovery, reorganized some dislocations into stable subgrain boundaries aligned with the axial direction, constructing highly efficient conductive channels. A second-stage low-temperature drawing further introduced high-density and ordered secondary dislocations within this framework. Finally, a stepped aging treatment ensured that the precipitates (β″ and β' phases) preferentially and strictly precipitated along the aforementioned regularly arranged dislocation lines, forming an ordered "precipitate-dislocation chain" composite structure.

[0076] The aluminum alloy is an Al-Mg-Si-Ce alloy, wherein the Mg content is 0.25 wt.%, the Si content is 0.40 wt.%, the Ce content is 0.4 wt.%, and the balance is Al and unavoidable impurities.

[0077] A multi-stage controlled preparation method for high-strength, high-conductivity Al-Mg-Si-Ce alloy wires is as follows:

[0078] (1) Casting aluminum alloy: Select raw materials according to composition content, preheat crucible to 500℃, add industrial pure aluminum and Al-Si master alloy, heat to 770℃ and hold for 45min; then cool the melt to 740℃, refine with C2Cl6 refining agent, the amount of refining agent added is 0.8% of the total mass of aluminum melt, hold for 15min; press in Al-8.8wt%Ce, Al-3B master alloy and pure magnesium ingot respectively; after holding, heat the melt to 730℃ and pour it into a columnar mold preheated to 210℃, finally obtain Al-Mg-Si-Ce alloy ingot;

[0079] (2) Homogenization treatment: The prepared aluminum alloy ingot is heated to 570°C at a rate of 6°C / min at room temperature and held for 8 hours. After the holding period, the alloy is immediately water-quenched to 160°C at a cooling rate of 210°C / s, and then air-cooled to room temperature.

[0080] (3) Hot extrusion billet: The homogenized ingot is hot extruded at 520°C with an extrusion ratio of 18 to obtain extruded bar stock;

[0081] (4) Rotary forging: The extruded bar is cooled to room temperature and then rotary forged at room temperature to reduce its diameter by 60% to form a dislocation array oriented along the axial direction, thus obtaining a rotary forged bar.

[0082] (5) Pre-aging treatment: The forged bar obtained in step (4) is heated to 185°C at a rate of 6°C / min at room temperature and held for 2 hours. Then the alloy is immediately quenched in water to 110°C at a cooling rate of 210°C / s and then air-cooled to room temperature.

[0083] (6) First-stage medium-temperature drawing: The bar obtained in step (5) is drawn in multiple passes at 250°C, with a total deformation of 60%, to obtain wire.

[0084] (7) Secondary low temperature drawing: The wire after the first drawing is drawn at room temperature (30°C) and the total deformation is 90% (relative to the size after step (6)).

[0085] (8) Low temperature peak aging stage: The drawn wire is heated to 170℃ at a rate of 6℃ / min and kept at that temperature for 8 hours;

[0086] (9) High temperature stabilization stage: The filament obtained in step (8) is heated to 225°C at a rate of 6°C / min and kept at that temperature for 1.5 hours, and then air-cooled to room temperature to obtain the finished product.

[0087] The β″ phase in the sample microstructure has a grain size of approximately 3.8 nm, a length of approximately 39.7 nm, and an areal density of 4.5 × 10⁻⁶. -3 / nm 2 The β' phase has a particle size of approximately 20.3 nm, a length of approximately 52.3 nm, and an areal density of 2.3 × 10⁻⁶. -3 / nm 2 The tensile strength is 309.4 MPa, and the conductivity is 54.6% IACS.

[0088] Comparative Example 1:

[0089] The difference between this comparative example and Example 1 is that the total deformation of the second-stage low-temperature drawing in step (7) is reduced from 80% to 50%; the β″ phase in the microstructure of the sample obtained in this comparative example has a grain size of approximately 4.0 nm, a length of approximately 40.5 nm, and an areal density of 2.4 × 10⁻⁶. -3 / nm 2 The β' phase has a particle size of approximately 20.9 nm, a length of approximately 53.2 nm, and an areal density of 2.0 × 10⁻⁶. -3 / nm 2 The tensile strength is 253.9 MPa, and the conductivity is 52.5% IACS.

[0090] In this comparative example, the total deformation of the secondary low-temperature drawing was reduced to 50%, which led to a significant reduction in the introduced dislocation density. This also means that in the subsequent low-temperature peak aging stage, the nucleation sites of the β'' phase decreased, the areal density of the β'' phase decreased significantly, and both precipitation strengthening (the most important strengthening mechanism) and dislocation strengthening were weakened, resulting in a significant decrease in strength.

[0091] Comparative Example 2:

[0092] The difference between this comparative example and Example 1 is that the low-temperature peak aging stage in step (8) is 140℃ / 4h; the particle size of the β″ phase in the sample obtained in this comparative example is about 1.8nm, the length is about 25.2nm, and the areal density is 2.0×10⁻⁶. -3 / nm 2 The β' phase has a particle size of approximately 11.2 nm, a length of approximately 36.9 nm, and an areal density of 1.7 × 10⁻⁶. -3 / nm 2 The tensile strength is 233.4 MPa, and the conductivity is 49.6% IACS.

[0093] The aging stage of this comparative example at the mid-to-low temperature peak was 140℃ / 4h, which is lower than the optimal precipitation temperature of the β'' phase. This slows down the atomic diffusion rate, making it difficult for Mg and Si atoms to aggregate and form β'' phase nuclei, resulting in a decrease in the nucleation rate and areal density of the β'' phase, thus significantly reducing its strength. In addition, due to the low aging temperature, the diffusion of solute atoms (Mg and Si) is insufficient, and most of Mg and Si remain dissolved in the Al matrix, causing strong scattering of conduction electrons, which increases the resistance to electron migration and reduces conductivity.

[0094] Comparative Example 3:

[0095] The difference between this comparative example and Example 1 is that the high-temperature stabilization stage is omitted in step (9); the particle size of the β'' phase in the sample microstructure obtained in this comparative example is approximately 2.0 nm, the length is approximately 27.1 nm, and the areal density is 4.4 × 10⁻⁶. -3 / nm 2 The β' phase is almost undetectable; the tensile strength is 343.4 MPa, and the conductivity is 44.1% IACS.

[0096] Detailed data of the aluminum alloys obtained in Examples 1 to 3 and Comparative Examples 1 to 3 of the present invention are shown in Table 1 below.

[0097] Table 1 Properties of High-Strength and High-Conductivity Aluminum Alloys

[0098]

[0099] Main testing methods:

[0100] Mechanical property testing:

[0101] Tensile tests were conducted on a CMT5105 electronic tensile testing machine. The tensile rate at room temperature was 2.0 mm / min. The dimensions and shape of the tensile specimens are as follows: Figure 1 As shown, the samples were cut directly from the sheet and profile according to the dimensions shown in the diagram using wire electrical discharge machining (EDM). All samples were taken from the center of the specimen. After appropriate heat treatment, the obtained samples were polished with fine sandpaper to remove the surface hardened layer produced by the wire EDM. The drawn wire was then stretched directly on a stretching machine, with a diameter of 3 mm and a gauge length of 12 mm.

[0102] Conductivity test:

[0103] The resistance of the sample was measured using a QJ36 single-arm / double-arm bridge. The measured resistance was converted to conductivity according to the international standard for annealed copper. (Conductor resistance) R resistivity ρ and the length of the conductor l Cross-sectional area s The relationship between them is:

[0104] ;

[0105] Known R , l , s Then the resistivity can be calculated. ρ .

[0106] Since the resistivity corresponding to the international standard for annealed copper is 1.7241 μΩ·cm, the conductivity of the sample is:

[0107] ;

[0108] The final data obtained is the average of the three test samples.

[0109] Electron backscatter diffraction (EBSD) analysis:

[0110] Samples used for EBSD testing must possess good conductivity and have clean, smooth, and stress-free surfaces. During sample preparation, the samples are first mechanically polished until the surface is bright and scratch-free, followed by electropolishing. The electropolishing solution consists of 10% HClO4 + 90% C2H5OH, with the temperature set at -20℃, the voltage constant at 32 V, and the electropolishing time at 60 s. After electropolishing, the sample is immersed face down in a beaker containing anhydrous ethanol for ultrasonic cleaning, then dried with a warm air blower, placed in a sample box, packaged, and vacuum-sealed, awaiting testing. The EBSD equipment used in this experiment is a Hitachi S-3400N. The results are then processed and analyzed using HKL-CHANNEL5 and Image Pro software to obtain the particle size, length, and areal density of the β' and β'' phases.

[0111] It should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the above description of exemplary embodiments of the invention. However, this method of disclosure should not be interpreted as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in fewer than all the features of the foregoingly disclosed embodiments. Therefore, the claims, following the detailed description, are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0112] Although the invention has been described with reference to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments are conceivable within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and instructional purposes, and not for the purpose of interpreting or limiting the subject matter of the invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the invention is illustrative and not restrictive, and the scope of the invention is defined by the appended claims.

[0113] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-strength, high-conductivity Al-Mg-Si-Ce alloy wire, characterized in that: The alloy wire has dislocation lines regularly arranged along the axial direction. The β′ phase and the β″ strengthening phase are regularly arranged along the dislocation lines. The β′ phase is β′-Mg2Si and the β″ strengthening phase is β″-Mg2Si. The alloy contains 0.15 wt.%~0.25 wt.%, 0.25 wt.%~0.40 wt.%, 0.20 wt.%~0.40 wt.%, and the balance is Al and unavoidable impurities; The multi-level controlled preparation method of the high-strength, high-conductivity Al-Mg-Si-Ce alloy wire includes the following steps: S01, Melting and casting: Obtaining aluminum alloy ingots; S02, Homogenization treatment: The prepared aluminum alloy ingot is heated to 550-570℃ at a rate of 4~6℃ / min at room temperature and held for 4-8 hours; after the holding period, the alloy is immediately water quenched to 140~160℃ at a cooling rate of 190~210℃ / s, and then air cooled to room temperature. S03, Hot extrusion billet: The homogenized ingot is hot extruded at 500-520℃ with an extrusion ratio of 14-18 to obtain extruded bars. S04, Rotary Forging: The extruded bar is cooled to room temperature and then rotary forged at room temperature to reduce its diameter by 40% to 60% in order to form dislocations that are oriented along the axial direction, thus obtaining a rotary forged bar. S05, Multi-stage deformation heat treatment: S05a, Pre-aging treatment: The forged bar obtained from S04 is heated to 175-185℃ at a rate of 4~6℃ / min at room temperature and held for 1-2 hours. Then, the alloy is immediately water-quenched to 90~110℃ at a cooling rate of 190~210℃ / s, and then air-cooled to room temperature. S05b, First-stage medium-temperature drawing: The bar obtained from S05a is drawn in multiple passes at an environment of 200-250℃, with a total deformation of 40-60%, to obtain wire. S05c, Secondary Low Temperature Drawing: The wire after the primary medium temperature drawing is drawn again at room temperature, with a total deformation of 80-90%; S05d, stepped aging treatment: S05d1, Low-temperature peak aging stage: The drawn wire is heated to 160-170℃ at a rate of 4~6℃ / min and held for 4-8 hours; S05d2, High-temperature stabilization stage: The filament obtained from S05d1 is heated to 215-225℃ at a rate of 4~6℃ / min and held at that temperature for 0.5-1.5 hours, and then air-cooled to room temperature to obtain the final product.

2. The high-strength, high-conductivity Al-Mg-Si-Ce alloy wire according to claim 1, characterized in that: The β'' reinforced phase has a particle size of 2.1-3.8 nm, a length of 27.4-39.7 nm, and an areal density of 4.5 × 10⁻⁶. -3 -5.8×10 -3 / nm 2 The β' phase has a particle size of 11.8–20.3 nm, a length of 43.4–52.3 nm, and an areal density of 2.2 × 10⁻⁶. -3 -2.8×10 -3 / nm 2 .

3. The high-strength, high-conductivity Al-Mg-Si-Ce alloy wire according to claim 1, characterized in that: The alloy wire has a tensile strength of 309.4~326.5MPa and a conductivity of 54.6~62.1%IACS.

4. A multi-stage controlled preparation method for high-strength, high-conductivity Al-Mg-Si-Ce alloy wires according to any one of claims 1 to 3, characterized in that: Includes the following steps: S01, Melting and casting: Obtaining aluminum alloy ingots; S02, Homogenization treatment: The prepared aluminum alloy ingot is heated to 550-570℃ at a rate of 4~6℃ / min at room temperature and held for 4-8 hours; after the holding period, the alloy is immediately water quenched to 140~160℃ at a cooling rate of 190~210℃ / s, and then air cooled to room temperature. S03, Hot extrusion billet: The homogenized ingot is hot extruded at 500-520℃ with an extrusion ratio of 14-18 to obtain extruded bars. S04, Rotary Forging: The extruded bar is cooled to room temperature and then rotary forged at room temperature to reduce its diameter by 40% to 60% in order to form dislocations that are oriented along the axial direction, thus obtaining a rotary forged bar. S05, Multi-stage deformation heat treatment: S05a, Pre-aging treatment: The forged bar obtained from S04 is heated to 175-185℃ at a rate of 4~6℃ / min at room temperature and held for 1-2 hours. Then, the alloy is immediately water-quenched to 90~110℃ at a cooling rate of 190~210℃ / s, and then air-cooled to room temperature. S05b, First-stage medium-temperature drawing: The bar obtained from S05a is drawn in multiple passes at an environment of 200-250℃, with a total deformation of 40-60%, to obtain wire. S05c, Secondary Low Temperature Drawing: The wire after the primary medium temperature drawing is drawn again at room temperature, with a total deformation of 80-90%; S05d, stepped aging treatment: S05d1, Low-temperature peak aging stage: The drawn wire is heated to 160-170℃ at a rate of 4~6℃ / min and held for 4-8 hours; S05d2, High-temperature stabilization stage: The filament obtained from S05d1 is heated to 215-225℃ at a rate of 4~6℃ / min and held at that temperature for 0.5-1.5 hours, and then air-cooled to room temperature to obtain the final product.

5. The multi-stage controlled preparation method for high-strength, high-conductivity Al-Mg-Si-Ce alloy wires according to claim 4, characterized in that: In S01, the casting method for aluminum alloy ingots is as follows: Select raw materials according to their composition and dry them in an oven at at least 200°C; preheat the crucible to 400-500°C, add industrial pure aluminum and Al-Si master alloy, raise the temperature to 750-770°C, and hold the furnace charge for 30-60 minutes after it has completely melted; then cool the melt to 730-750°C and refine it using C2Cl6 as the refining agent, with the amount of refining agent added being 0.6-0.8% of the total mass of the aluminum melt; skim off the slag, and hold it at the temperature for 10-20 minutes; press in Al-8.8wt%Ce, Al-3B master alloy and pure magnesium ingots respectively; after holding, raise the temperature of the melt to 720-730°C and pour it into a cylindrical mold preheated to 200-220°C to finally obtain the Al-Mg-Si-Ce alloy ingot.

6. The multi-stage controlled preparation method for high-strength, high-conductivity Al-Mg-Si-Ce alloy wires according to claim 4, characterized in that: In S05, both the pre-aging treatment and the step aging treatment are carried out under nitrogen protection.

7. The multi-stage controlled preparation method for high-strength, high-conductivity Al-Mg-Si-Ce alloy wires according to claim 4, characterized in that: In S04, the diameter reduction during rotary forging is 50%.

8. The application of the high-strength, high-conductivity Al-Mg-Si-Ce alloy wire according to any one of claims 1 to 3 in materials that combine lightweight and ultra-long service life.

9. The application according to claim 8, characterized in that: Materials with lightweight and ultra-long service life include power transmission and distribution materials, rail transit materials, and aerospace materials; power transmission and distribution materials include overhead conductors, electromagnetic wires, winding wires, cable cores, and busbars.

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