High-strength high-conductivity aluminum alloy electrical conductor material and preparation method thereof

Abstract

The application discloses a high-strength and high-conductivity aluminum alloy electric conductor material and a preparation method thereof, and belongs to the technical field of aluminum alloy materials. The high-strength and high-conductivity aluminum alloy electric conductor material comprises the following components in percentage by weight: Si: 0.4-0.8%, Mg: 0.5-0.9%, Cu: 0.05-0.2%, B: 0.01-0.15%, Zr: 0-0.25%, rare earth elements: 0.15-0.35%, unavoidable impurity elements: ≤0.15%, and the balance is aluminum. The rare earth elements are composed of La, Ce, Sm and Gd. The raw materials are mixed, smelted and purified to obtain a melt, then the melt is subjected to shear force treatment to obtain a semi-solid slurry, the semi-solid slurry is injected into a mold of an extrusion casting device to be extrusion formed into a blank, and the blank is subjected to artificial aging treatment to obtain an aluminum alloy conductor material with high strength, high conductivity, excellent heat resistance and processing plasticity. The application solves the problem that the strength, conductivity and heat resistance of the aluminum alloy conductor material cannot be simultaneously improved in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy material technology, specifically relating to a high-strength, high-conductivity aluminum alloy electrical conductor material and its preparation method. Background Technology

[0002] Aluminum alloy conductors are widely used in power transmission due to their advantages such as light weight, low cost, and good conductivity. However, traditional aluminum alloy conductors suffer from insufficient strength, poor heat resistance, and inadequate creep resistance, making it difficult to meet the higher performance requirements of emerging fields such as ultra-high voltage power transmission and new energy vehicles. Currently, the performance of aluminum alloy conductors is improved by adding alloying elements and optimizing processing technology. For example, introducing rare earth elements into aluminum alloys can improve their microstructure and overall performance. However, existing research on rare earth aluminum alloy conductors mainly focuses on the application of single or binary rare earth components, which makes it difficult to fully utilize the value of rare earth elements. Furthermore, most schemes follow the long process of traditional continuous casting and rolling-drawing-intermediate annealing, resulting in the elongation of coarse needle-like eutectic Si along the rolling direction, with grain sizes generally greater than 40 μm, uneven distribution of strengthening phases, and heat resistance relying on subsequent long-term multi-stage aging, leading to high energy consumption and limited yield. Even though a few schemes mention semi-solid forming, they only reach the stage of simple stirring or low-shear injection. The solid fraction control is crude, the casting temperature window is too wide, and it is impossible to effectively break dendrites and spheroidize Si phases. It is also impossible to work with rare earth elements to play a refining and dispersion strengthening role, which makes it difficult to improve strength, conductivity and heat resistance at the same time. Summary of the Invention

[0003] To address the aforementioned shortcomings, this invention discloses a high-strength, high-conductivity aluminum alloy electrical conductor material and its preparation method. By optimizing the composition design and preparation process, an aluminum alloy conductor material with high strength, high conductivity, excellent heat resistance, and processing plasticity is prepared.

[0004] This invention is achieved using the following technical solution:

[0005] A high-strength, high-conductivity aluminum alloy electrical conductor material comprises the following components by weight percentage: Si: 0.4%–0.8%, Mg: 0.5%–0.9%, Cu: 0.05%–0.2%, B: 0.01%–0.15%, Zr: 0–0.25%, rare earth elements: 0.15%–0.35%, other unavoidable impurity elements totaling ≤0.15%, with the balance being aluminum;

[0006] The rare earth elements are composed of La, Ce, Sm and Gd, and the weight ratio of La to Ce is (1~2):1, the weight ratio of Sm to Gd is (1~2):1, and the weight ratio of Ce to Sm is (1~2):1.

[0007] The microstructure of the aluminum alloy electrical conductor material includes fine, rounded equiaxed crystals in the α-Al matrix, Mg2Si phase, Al3Zr phase, and the following particles: Al 11 (La,Ce)3, Al2Si2(La,Ce,Sm,Gd), Al3Sm, Al3Gd.

[0008] The resulting high-strength, high-conductivity aluminum alloy electrical conductor material has a tensile strength ≥320MPa, conductivity ≥58%IACS, strength retention rate ≥90% at 230℃×1h, and elongation ≥10%, and can be used in the production of high-end heat-resistant and capacity-enhancing overhead conductors and wiring harnesses for new energy vehicles.

[0009] Further optimization and improvement resulted in a Si to Mg weight ratio of (0.8 to 1.2):1, which allows Mg and Si elements to fully form the Mg2Si strengthening phase, thereby improving the strength of the alloy.

[0010] Further optimization and improvement involves adding B element at a weight percentage of 0.05% to 0.15% and Zr element at a weight percentage of 0.05% to 0.2%. Adding B element in this proportion can better refine the grains and improve processing performance. At the same time, the proportionally added Zr element can better increase the recrystallization temperature of the alloy and enhance its heat resistance.

[0011] The method for preparing the high-strength, high-conductivity aluminum alloy electrical conductor material includes the following steps:

[0012] (1) Alloy smelting: Weigh aluminum ingots, copper ingots, magnesium ingots, silicon ingots, and intermediate alloys composed of any two or more elements from Si, Mg, Cu, B, Zr, La, Ce, Sm and Gd as raw materials according to the proportion, and then smelt the raw materials at 710℃~780℃ to obtain intermediate melt.

[0013] (2) Melt purification: The intermediate melt obtained in step (1) is degassed by rotating argon gas with a purity of 99.9%, and then filtered to obtain purified melt;

[0014] (3) Preparation of thixotropic slurry: The purified melt obtained in step (2) is cooled to 610℃~650℃, and then a shear force is applied to the purified melt, with the shear rate controlled at 500s. -1 ~1200s -1 The application time is controlled within 30s to 60s, and then a semi-solid slurry with a solid phase ratio of 15% to 25% is obtained. The viscosity of the semi-solid slurry is 0.10 Pa·s to 0.15 Pa·s.

[0015] (4) Rheological forming: Using extrusion casting equipment, the semi-solid slurry obtained in step (3) is injected into the preheated mold in 0.5s to 1.5s, then a pressure of 150MPa to 250MPa is applied and held for 5s to 10s, then the mold is cooled and the cooling rate is controlled to be ≥50℃ / s. After cooling, the mold is opened to obtain the billet.

[0016] (5) Post-processing: The blank obtained in step (4) is artificially aged at 180℃~190℃ for 5h~6h to obtain a high-strength and high-conductivity aluminum alloy electrical conductor material.

[0017] Further optimization and improvement: the filtration in step (2) adopts a two-stage filtration method. First, the degassed intermediate melt is filtered with a ceramic filter with a porosity of 30 PPI, and then a ceramic filter with a porosity of 50 PPI is used to obtain the purified melt. The hydrogen content in the purified melt is ≤0.12 mL / 100 g. The determination of hydrogen content can refer to GB / T 32186-2015 "Test Method for Purity of Aluminum and Aluminum Alloy Ingots".

[0018] Further optimization and improvement: In step (3), when the online spectrometer detects that the total RE content in the purified melt is less than 0.12 wt% or the weight ratio of La to Ce is less than 1.0, Al and intermediate alloys of La, Ce, Sm, and Gd are immediately added to the purified melt, while the shear rate is controlled at 300 s. -1 ~400s -1 When the online spectrometer detects that the Mg content in the semi-solid slurry is greater than 1.0 wt%, high-purity aluminum ingots are added for mixing, and the temperature of the semi-solid slurry is increased by 5℃ to 8℃. When the total amount of rare earth elements (RE) drops, it is necessary to replenish the material immediately, such as by adding RE enrichment fibers (Al-10RE), while reducing the shear rate to a suitable range to prevent coarsening of the rare earth-rich phase. When the magnesium content is too high, high-purity aluminum ingots can be added for dilution, and the slurry temperature can be increased simultaneously to maintain the solid fraction within the specified range, thereby avoiding subsequent rheological pressure overload.

[0019] Further optimization and improvement: In step (3), after applying shear force to the purified melt, a rotating magnetic field is applied for 5s to 10s to obtain a semi-solid slurry. The intensity of the rotating magnetic field is 0.20T to 0.30T. Applying shear force to the purified melt first, and then applying a suitable rotating magnetic field, can induce secondary eddies to throw the Sm-Gd rich liquid film into the lattice edge, forming 30 nm GP clusters, thereby improving the alloy performance.

[0020] Further optimization and improvement: In step (3), during the last 10 to 20 seconds of shear force application, Al-5Ti-1B alloy is added to the purified melt, and the weight of the added Al-5Ti-1B alloy is 0.05% of the weight of the purified melt. The added Al-5Ti-1B alloy works synergistically with Sm-Gd, using TiB2 particles as heterogeneous cores to further refine the α-Al grains. At the same time, the Gd vacancy binding energy reaches 0.92 eV, which can capture vacancies and suppress diffusion creep.

[0021] Further optimization and improvement: in step (4), the mold is preheated to 250°C to 300°C before the semi-solid slurry is injected.

[0022] Further optimization and improvement: in step (4), helium is used to cool the mold. Specifically, 5MPa helium is used for 2s to 3s, and then 2MPa helium is used for 3s to 5s.

[0023] Compared with existing technologies, this technical solution has the following advantages:

[0024] 1. The quaternary rare earth components used in this invention fully leverage the value of rare earth elements through synergistic effects. For example, La and Ce effectively purify the aluminum matrix and optimize grain boundary states, laying the foundation for high conductivity; Sm and Gd significantly improve the material's heat resistance and creep resistance by forming a highly thermally stable dispersed reinforcing phase. The quaternary rare earth system described in this invention can ensure a conductivity of not less than 58% IACS while enabling the conductor to possess both excellent mechanical strength and high-temperature stability. This effectively solves the technical problem of traditional conductors being unable to balance conductivity and heat resistance, providing a more optimized material solution for developing high-performance transmission conductors.

[0025] 2. This invention systematically introduces thixotropic rheometry into the preparation process of rare-earth aluminum alloy wires for the first time. It obtains a semi-solid slurry with a solid fraction of 15-25%, α-Al grain size ≤15μm, and eutectic Si spheroidization ≥80% in a very short time. Electromagnetic-mechanical composite stirring is used to uniformly disperse the La-Ce-Sm-Gd quaternary rare earth elements in the melt, which then instantly solidifies to form 30-100nm Al3RE and AlSiRE nanophases. Grain boundaries and dislocations are doubly pinned, achieving a "nanophase-fine" effect. The rare earth compounds exhibit dual strengthening properties, and their resistivity is lower than that of transition metal compounds, resulting in minimal impact on electron scattering. This balances strengthening and conductivity, producing aluminum alloy wires with tensile strength ≥320MPa, conductivity ≥58%IACS, and strength retention ≥90% at 230℃ for 1 hour. This makes them suitable for producing high-end heat-resistant, capacity-enhancing overhead conductors and wiring harnesses for new energy vehicles. For example, the material can be cold-drawn into fine filaments with a diameter of less than 2mm, and then coated with steel or carbon fiber to produce 1000 mm² wires. 2Large-section capacity-enhancing wires can also be stranded to form high-voltage 800 V wiring harnesses for new energy vehicles.

[0026] 3. This invention innovatively integrates thixotropic rheology with La-Ce-Sm-Gd quaternary rare earth synergistic microalloying, achieving one-step grain refinement, eutectic Si spheroidization, and nano-Al3RE dispersion precipitation in semi-solid high-shear instantaneous forming. This breaks through the bottleneck of traditional aluminum alloy conductors, which cannot simultaneously achieve "strength-conductivity-heat resistance". It enables the material to achieve a breakthrough leap in comprehensive performance, with tensile strength ≥320MPa, electrical conductivity ≥58% IACS, and strength retention rate ≥90% at 230℃×1h. At the same time, it shortens the process, reduces energy consumption, and improves the yield. The short process of melt purification-thixotropic slurry-one near-net-shape forming adopted has the advantages of less head and tail cutting loss and higher yield compared with the traditional three-step process of "continuous casting and rolling-drawing-intermediate annealing". At the same time, the use of La-Ce-Sm-Gd mixed rare earth eliminates the need for separation and purification, reduces the total amount used, and rationally combines light and heavy rare earth elements, reducing the consumption of heavy rare earth elements. Attached Figure Description

[0027] Figure 1 This is a scanning electron microscope image of the microstructure of the high-strength, high-conductivity aluminum alloy electrical conductor material described in Example 1.

[0028] Figure 2 The image is an electronic image obtained from EDS mapping detection and analysis of the high-strength and high-conductivity aluminum alloy electrical conductor material described in Example 1.

[0029] Figure 3 This is the Al element distribution map obtained from the EDS Mapping detection and analysis of the high-strength and high-conductivity aluminum alloy electrical conductor material described in Example 1.

[0030] Figure 4 This is the Mg element distribution map obtained from the EDS Mapping detection and analysis of the high-strength and high-conductivity aluminum alloy electrical conductor material described in Example 1.

[0031] Figure 5 The image shows the Si element distribution obtained from EDS mapping analysis of the high-strength, high-conductivity aluminum alloy electrical conductor material described in Example 1.

[0032] Figure 6 The image shows the La element distribution obtained from EDS mapping analysis of the high-strength, high-conductivity aluminum alloy electrical conductor material described in Example 1.

[0033] Figure 7 The image shows the Ce element distribution obtained from EDS mapping analysis of the high-strength, high-conductivity aluminum alloy electrical conductor material described in Example 1.

[0034] Figure 8 The image shows the Gd element distribution obtained from EDS mapping analysis of the high-strength, high-conductivity aluminum alloy electrical conductor material described in Example 1.

[0035] Figure 9 This is the Sm element distribution map obtained from the EDS Mapping detection and analysis of the high-strength and high-conductivity aluminum alloy electrical conductor material described in Example 1.

[0036] Figure 10 This is a scanning electron microscope image of the microstructure of the high-strength, high-conductivity aluminum alloy electrical conductor material described in Example 2. Detailed Implementation

[0037] The present invention is further illustrated by the following examples, but these are not intended to limit the invention. Specific experimental conditions and methods not specified in the following examples are generally conventional methods well known to those skilled in the art.

[0038] Example 1: A high-strength and high-conductivity aluminum alloy electrical conductor material, comprising the following components by weight percentage: Si: 0.4%, Mg: 0.5%, Cu: 0.05%, B: 0.01%, rare earth elements: 0.15%, other unavoidable impurity elements totaling 0.15%, with the balance being aluminum;

[0039] The rare earth elements are composed of La, Ce, Sm, and Gd, and the weight ratio of La to Ce is 1.2:1, the weight ratio of Sm to Gd is 1.5:1, and the weight ratio of Ce to Sm is 1.3:1.

[0040] The microstructure of the aluminum alloy electrical conductor material includes fine, rounded equiaxed crystals in the α-Al matrix, Mg2Si phase, Al3Zr phase, and the following particles: Al 11 (La,Ce)3, Al2Si2(La,Ce,Sm,Gd), Al3Sm, Al3Gd.

[0041] The method for preparing the high-strength, high-conductivity aluminum alloy electrical conductor material includes the following steps:

[0042] (1) Alloy smelting: Weigh aluminum ingots, copper ingots, magnesium ingots, silicon ingots, and intermediate alloys composed of any two or more elements from Si, Mg, Cu, B, Zr, La, Ce, Sm and Gd as raw materials according to the proportion, and then smelt the raw materials at 710°C to obtain intermediate melt.

[0043] (2) Melt purification: The intermediate melt obtained in step (1) is degassed by rotary purging with argon gas of 99.9% purity, and then filtered to obtain purified melt; the filtration adopts a two-stage filtration method, first filtering the degassed intermediate melt with ceramic with a porosity of 30 PPI, and then filtering with ceramic with a porosity of 50 PPI to obtain purified melt, the hydrogen content in the purified melt is 0.12 mL / 100 g;

[0044] (3) Preparation of thixotropic slurry: The purified melt obtained in step (2) is cooled to 625°C, and then a shear force is applied to the purified melt, with the shear rate controlled at 500 s. -1 The application time is controlled within 60 seconds. After applying shear force for 40 seconds, Al-5Ti-1B alloy is added to the purified melt, and the weight of the added Al-5Ti-1B alloy is 0.05% of the weight of the purified melt. Then, shear force is applied for another 20 seconds, followed by a rotating magnetic field treatment for 5 seconds to obtain a semi-solid slurry with a solid fraction of 15% and a viscosity of 0.15 Pa·s. The strength of the rotating magnetic field is 0.30 T.

[0045] When the online spectrometer detects that the total RE content in the purified melt is less than 0.12 wt% or the weight ratio of La to Ce is less than 1.0, Al and La, Ce, Sm, and Gd intermediate alloys are immediately added to the purified melt, while the shear rate is controlled at 300 s⁻¹. -1 When the online spectrometer detects that the Mg content in the semi-solid slurry is greater than 1.0 wt%, high-purity aluminum ingots are added and mixed, and the temperature of the semi-solid slurry is increased by 5°C.

[0046] (4) Rheological forming: Using extrusion casting equipment and preheating the mold to 260°C, the semi-solid slurry obtained in step (3) is injected into the preheated mold made of graphite-silicon nitride composite within 0.5s. Then, a pressure of 150MPa is applied and held for 10s. The mold is then cooled by introducing helium into the mold wall. First, 5MPa of helium is introduced for 2s, and then 2MPa of helium is introduced for 3s. After cooling, the mold is opened to obtain the billet.

[0047] (5) Post-processing: The billet obtained in step (4) is artificially aged at 180℃ for 6 hours to obtain a high-strength, high-conductivity aluminum alloy electrical conductor material. The obtained aluminum alloy electrical conductor material is then subjected to scanning electron microscopy (SEM) to obtain the following results: Figure 1 The scanning electron microscope image shown is illustrated below. Simultaneously, EDS mapping analysis was performed on the obtained aluminum alloy electrical conductor material, and the resulting electron image is shown below. Figure 2 As shown, Figures 3-9The following are elemental distribution diagrams for Al, Mg, Si, La, Ce, Gd, and Sm, respectively. Based on these images, it can be seen that the obtained aluminum alloy electrical conductor material contains fine, rounded equiaxed crystals of the α-Al matrix, the Mg2Si phase, the Al3Zr phase, and the following particles: Al 11 (La,Ce)3, Al2Si2(La,Ce,Sm,Gd), Al3Sm, Al3Gd.

[0048] Example 2: A high-strength and high-conductivity aluminum alloy electrical conductor material, comprising the following components by weight percentage: Si: 0.75%, Mg: 0.9%, Cu: 0.1%, B: 0.05%, Zr: 0.05%, rare earth elements: 0.28%, other unavoidable impurity elements totaling 0.12%, with the balance being aluminum;

[0049] The rare earth elements are composed of La, Ce, Sm, and Gd, and the weight ratio of La to Ce is 1.4:1, the weight ratio of Sm to Gd is 1.5:1, and the weight ratio of Ce to Sm is 1.2:1.

[0050] The microstructure of the aluminum alloy electrical conductor material includes fine, rounded equiaxed crystals in the α-Al matrix, Mg2Si phase, Al3Zr phase, and the following particles: Al 11 (La,Ce)3, Al2Si2(La,Ce,Sm,Gd), Al3Sm, Al3Gd.

[0051] The method for preparing the high-strength, high-conductivity aluminum alloy electrical conductor material includes the following steps:

[0052] (1) Alloy smelting: Weigh aluminum ingots, copper ingots, magnesium ingots, silicon ingots, and intermediate alloys composed of any two or more elements from Si, Mg, Cu, B, Zr, La, Ce, Sm and Gd as raw materials according to the proportion, and then smelt the raw materials at 730°C to obtain intermediate melt.

[0053] (2) Melt purification: The intermediate melt obtained in step (1) is degassed by rotary purging with argon gas of 99.9% purity, and then filtered to obtain purified melt; the filtration adopts a two-stage filtration method, first filtering the degassed intermediate melt with ceramic with a porosity of 30 PPI, and then filtering with ceramic with a porosity of 50 PPI to obtain purified melt, the hydrogen content in the purified melt is 0.11 mL / 100 g;

[0054] (3) Preparation of thixotropic slurry: The purified melt obtained in step (2) is cooled to 610°C, and then a shear force is applied to the purified melt, with the shear rate controlled at 800 s. -1The application time is controlled within 40 seconds. After applying shear force for 25 seconds, Al-5Ti-1B alloy is added to the purified melt, and the weight of the added Al-5Ti-1B alloy is 0.05% of the weight of the purified melt. Then, shear force is applied for another 15 seconds, followed by a rotating magnetic field treatment for 6 seconds to obtain a semi-solid slurry with a solid fraction of 18% and a viscosity of 0.12 Pa·s. The strength of the rotating magnetic field is 0.25 T.

[0055] When the online spectrometer detects that the total RE content in the purified melt is less than 0.12 wt% or the weight ratio of La to Ce is less than 1.0, Al and La, Ce, Sm, and Gd intermediate alloys are immediately added to the purified melt, while the shear rate is controlled at 400 s⁻¹. -1 When the online spectrometer detects that the Mg content in the semi-solid slurry is greater than 1.0 wt%, high-purity aluminum ingots are added and mixed, and the temperature of the semi-solid slurry is increased by 6°C.

[0056] (4) Rheological forming: Using extrusion casting equipment and preheating the mold to 280°C, the semi-solid slurry obtained in step (3) is injected into the preheated mold made of graphite-silicon nitride composite within 0.8s. Then, a pressure of 200MPa is applied and held for 8s. The mold is then cooled by introducing helium into the mold wall. First, 5MPa of helium is introduced for 2s, and then 2MPa of helium is introduced for 4s. After cooling, the mold is opened to obtain the billet.

[0057] (5) Post-processing: The billet obtained in step (4) is artificially aged at 190℃ for 5 hours to obtain a high-strength, high-conductivity aluminum alloy electrical conductor material. The obtained aluminum alloy electrical conductor material is then subjected to scanning electron microscopy (SEM) to obtain the following results: Figure 10 The scanning electron microscope image shown.

[0058] Example 3: A high-strength and high-conductivity aluminum alloy electrical conductor material, comprising the following components by weight percentage: Si: 0.6%, Mg: 0.6%, Cu: 0.08%, B: 0.1%, Zr: 0.2%, rare earth elements: 0.30%, other unavoidable impurity elements totaling 0.14%, with the balance being aluminum;

[0059] The rare earth elements are composed of La, Ce, Sm and Gd, and the weight ratio of La to Ce is 2:1, the weight ratio of Sm to Gd is 2:1, and the weight ratio of Ce to Sm is 2:1.

[0060] The microstructure of the aluminum alloy electrical conductor material includes fine, rounded equiaxed crystals in the α-Al matrix, Mg2Si phase, Al3Zr phase, and the following particles: Al 11(La,Ce)3, Al2Si2(La,Ce,Sm,Gd), Al3Sm, Al3Gd.

[0061] The method for preparing the high-strength, high-conductivity aluminum alloy electrical conductor material includes the following steps:

[0062] (1) Alloy smelting: Weigh aluminum ingots, copper ingots, magnesium ingots, silicon ingots, and intermediate alloys composed of any two or more elements from Si, Mg, Cu, B, Zr, La, Ce, Sm and Gd as raw materials according to the proportion, and then smelt the raw materials at 750°C to obtain intermediate melt.

[0063] (2) Melt purification: The intermediate melt obtained in step (1) is degassed by rotary purging with argon gas of 99.9% purity, and then filtered to obtain purified melt; the filtration adopts a two-stage filtration method, first filtering the degassed intermediate melt with ceramic with a porosity of 30 PPI, and then filtering with ceramic with a porosity of 50 PPI to obtain purified melt, the hydrogen content in the purified melt is 0.12 mL / 100 g;

[0064] (3) Preparation of thixotropic slurry: The purified melt obtained in step (2) is cooled to 630°C, and then a shear force is applied to the purified melt, with the shear rate controlled at 1000 s. -1 The application time is controlled within 50 seconds. After applying shear force for 35 seconds, Al-5Ti-1B alloy is added to the purified melt, and the weight of the added Al-5Ti-1B alloy is 0.05% of the weight of the purified melt. Then, shear force is applied for another 15 seconds, followed by a rotating magnetic field treatment for 8 seconds to obtain a semi-solid slurry with a solid phase content of 20% and a viscosity of 0.13 Pa·s. The strength of the rotating magnetic field is 0.25 T.

[0065] When the online spectrometer detects that the total RE content in the purified melt is less than 0.12 wt% or the weight ratio of La to Ce is less than 1.0, Al and La, Ce, Sm, and Gd intermediate alloys are immediately added to the purified melt, while the shear rate is controlled at 300 s⁻¹. -1 When the online spectrometer detects that the Mg content in the semi-solid slurry is greater than 1.0 wt%, high-purity aluminum ingots are added and mixed, and the temperature of the semi-solid slurry is increased by 8°C.

[0066] (4) Rheological forming: Using extrusion casting equipment and preheating the mold to 280°C, the semi-solid slurry obtained in step (3) is injected into the preheated mold made of graphite-silicon nitride composite within 1.0s. Then, a pressure of 180MPa is applied and held for 8s. Then, the mold is cooled by introducing helium into the mold wall. First, 5MPa of helium is introduced for 3s, and then 2MPa of helium is introduced for 3s. After cooling, the mold is opened to obtain the billet.

[0067] (5) Post-processing: The blank obtained in step (4) is artificially aged at 185°C for 6 hours to obtain a high-strength and high-conductivity aluminum alloy electrical conductor material.

[0068] Example 4: A high-strength and high-conductivity aluminum alloy electrical conductor material, comprising the following components by weight percentage: Si: 0.65%, Mg: 0.7%, Cu: 0.12%, B: 0.1%, Zr: 0.1%, rare earth elements: 0.32%, other unavoidable impurity elements totaling 0.15%, with the balance being aluminum;

[0069] The rare earth elements are composed of La, Ce, Sm, and Gd, and the weight ratio of La to Ce is 1.5:1, the weight ratio of Sm to Gd is 1.5:1, and the weight ratio of Ce to Sm is 1.6:1.

[0070] The microstructure of the aluminum alloy electrical conductor material includes fine, rounded equiaxed crystals in the α-Al matrix, Mg2Si phase, Al3Zr phase, and the following particles: Al 11 (La,Ce)3, Al2Si2(La,Ce,Sm,Gd), Al3Sm, Al3Gd.

[0071] The method for preparing the high-strength, high-conductivity aluminum alloy electrical conductor material includes the following steps:

[0072] (1) Alloy smelting: Weigh aluminum ingots, copper ingots, magnesium ingots, silicon ingots, and intermediate alloys composed of any two or more elements from Si, Mg, Cu, B, Zr, La, Ce, Sm and Gd as raw materials according to the proportion, and then smelt the raw materials at 760°C to obtain intermediate melt.

[0073] (2) Melt purification: The intermediate melt obtained in step (1) is degassed by rotary purging with argon gas of 99.9% purity, and then filtered to obtain purified melt; the filtration adopts a two-stage filtration method, first filtering the degassed intermediate melt with ceramic with a porosity of 30 PPI, and then filtering with ceramic with a porosity of 50 PPI to obtain purified melt, the hydrogen content in the purified melt is 0.12 mL / 100 g;

[0074] (3) Preparation of thixotropic slurry: The purified melt obtained in step (2) is cooled to 620°C, and then a shear force is applied to the purified melt, with the shear rate controlled at 1000 s. -1 The application time is controlled within 30 seconds. After applying shear force for 20 seconds, Al-5Ti-1B alloy is added to the purified melt, and the weight of the added Al-5Ti-1B alloy is 0.05% of the weight of the purified melt. Then, shear force is applied for another 10 seconds, followed by a rotating magnetic field treatment for 8 seconds to obtain a semi-solid slurry with a solid fraction of 20% and a viscosity of 0.12 Pa·s. The strength of the rotating magnetic field is 0.25 T.

[0075] When the online spectrometer detects that the total RE content in the purified melt is less than 0.12 wt% or the weight ratio of La to Ce is less than 1.0, Al and La, Ce, Sm, and Gd intermediate alloys are immediately added to the purified melt, while the shear rate is controlled at 400 s⁻¹. -1 When the online spectrometer detects that the Mg content in the semi-solid slurry is greater than 1.0 wt%, high-purity aluminum ingots are added and mixed, and the temperature of the semi-solid slurry is increased by 8°C.

[0076] (4) Rheological forming: Using extrusion casting equipment and preheating the mold to 280°C, the semi-solid slurry obtained in step (3) is injected into the preheated mold made of graphite-silicon nitride composite within 0.6s. Then, a pressure of 250MPa is applied and held for 5s. Then, the mold is cooled by introducing helium into the mold wall. First, 5MPa of helium is introduced for 3s, and then 2MPa of helium is introduced for 5s. After cooling, the mold is opened to obtain the billet.

[0077] (5) Post-processing: The blank obtained in step (4) is artificially aged at 180°C for 6 hours to obtain a high-strength and high-conductivity aluminum alloy electrical conductor material.

[0078] Example 5: A high-strength and high-conductivity aluminum alloy electrical conductor material, comprising the following components by weight percentage: Si: 0.7%, Mg: 0.75%, Cu: 0.15%, B: 0.12%, Zr: 0.15%, rare earth elements: 0.28%, other unavoidable impurity elements totaling 0.12%, with the balance being aluminum;

[0079] The rare earth elements are composed of La, Ce, Sm, and Gd, and the weight ratio of La to Ce is 1.5:1, the weight ratio of Sm to Gd is 1.2:1, and the weight ratio of Ce to Sm is 1.8:1.

[0080] The microstructure of the aluminum alloy electrical conductor material includes fine, rounded equiaxed crystals in the α-Al matrix, Mg2Si phase, Al3Zr phase, and the following particles: Al 11 (La,Ce)3, Al2Si2(La,Ce,Sm,Gd), Al3Sm, Al3Gd.

[0081] The method for preparing the high-strength, high-conductivity aluminum alloy electrical conductor material includes the following steps:

[0082] (1) Alloy smelting: Weigh aluminum ingots, copper ingots, magnesium ingots, silicon ingots, and intermediate alloys composed of any two or more elements from Si, Mg, Cu, B, Zr, La, Ce, Sm and Gd as raw materials according to the proportion, and then smelt the raw materials at 750°C to obtain intermediate melt.

[0083] (2) Melt purification: The intermediate melt obtained in step (1) is degassed by rotary purging with argon gas of 99.9% purity, and then filtered to obtain purified melt; the filtration adopts a two-stage filtration method, first filtering the degassed intermediate melt with ceramic with a porosity of 30 PPI, and then filtering with ceramic with a porosity of 50 PPI to obtain purified melt, wherein the hydrogen content in the purified melt is 0.10 mL / 100 g;

[0084] (3) Preparation of thixotropic slurry: The purified melt obtained in step (2) is cooled to 625°C, and then a shear force is applied to the purified melt, with the shear rate controlled at 1200 s. -1 The application time is controlled within 40 seconds. After applying shear force for 30 seconds, Al-5Ti-1B alloy is added to the purified melt, and the weight of the added Al-5Ti-1B alloy is 0.05% of the weight of the purified melt. Then, shear force is applied for another 10 seconds, followed by a rotating magnetic field treatment for another 10 seconds to obtain a semi-solid slurry with a solid fraction of 20% and a viscosity of 0.12 Pa·s. The strength of the rotating magnetic field is 0.25 T.

[0085] When the online spectrometer detects that the total RE content in the purified melt is less than 0.12 wt% or the weight ratio of La to Ce is less than 1.0, Al and La, Ce, Sm, and Gd intermediate alloys are immediately added to the purified melt, while the shear rate is controlled at 400 s⁻¹. -1 When the online spectrometer detects that the Mg content in the semi-solid slurry is greater than 1.0 wt%, high-purity aluminum ingots are added and mixed, and the temperature of the semi-solid slurry is increased by 6°C.

[0086] (4) Rheological forming: Using extrusion casting equipment and preheating the mold to 280°C, the semi-solid slurry obtained in step (3) is injected into the preheated mold made of graphite-silicon nitride composite within 1.2s. Then, a pressure of 220MPa is applied and held for 6s. The mold is then cooled by introducing helium into the mold wall. First, 5MPa of helium is introduced for 3s, and then 2MPa of helium is introduced for 4s. After cooling, the mold is opened to obtain the billet.

[0087] (5) Post-processing: The blank obtained in step (4) is artificially aged at 180°C for 6 hours to obtain a high-strength and high-conductivity aluminum alloy electrical conductor material.

[0088] Example 6: A high-strength and high-conductivity aluminum alloy electrical conductor material, comprising the following components by weight percentage: Si: 0.8%, Mg: 0.67%, Cu: 0.2%, B: 0.15%, Zr: 0.25%, rare earth elements: 0.30%, other unavoidable impurity elements totaling 0.15%, with the balance being aluminum;

[0089] The rare earth elements are composed of La, Ce, Sm and Gd, and the weight ratio of La to Ce is 1:1, the weight ratio of Sm to Gd is 1:1, and the weight ratio of Ce to Sm is 1:1.

[0090] The microstructure of the aluminum alloy electrical conductor material includes fine, rounded equiaxed crystals in the α-Al matrix, Mg2Si phase, Al3Zr phase, and the following particles: Al 11 (La,Ce)3, Al2Si2(La,Ce,Sm,Gd), Al3Sm, Al3Gd.

[0091] The method for preparing the high-strength, high-conductivity aluminum alloy electrical conductor material includes the following steps:

[0092] (1) Alloy smelting: Weigh aluminum ingots, copper ingots, magnesium ingots, silicon ingots, and intermediate alloys composed of any two or more elements from Si, Mg, Cu, B, Zr, La, Ce, Sm and Gd as raw materials according to the proportion, and then smelt the raw materials at 780°C to obtain intermediate melt.

[0093] (2) Melt purification: The intermediate melt obtained in step (1) is degassed by rotary purging with argon gas of 99.9% purity, and then filtered to obtain purified melt; the filtration adopts a two-stage filtration method, first filtering the degassed intermediate melt with ceramic with a porosity of 30 PPI, and then filtering with ceramic with a porosity of 50 PPI to obtain purified melt, the hydrogen content in the purified melt is 0.12 mL / 100 g;

[0094] (3) Preparation of thixotropic slurry: The purified melt obtained in step (2) is cooled to 650°C, and then a shear force is applied to the purified melt, with the shear rate controlled at 1200 s. -1 The application time is controlled within 30 seconds. After applying shear force for 20 seconds, Al-5Ti-1B alloy is added to the purified melt, and the weight of the added Al-5Ti-1B alloy is 0.05% of the weight of the purified melt. Then, shear force is applied for another 10 seconds, followed by a rotating magnetic field treatment for another 10 seconds to obtain a semi-solid slurry with a solid content of 25% and a viscosity of 0.10 Pa·s. The strength of the rotating magnetic field is 0.20 T.

[0095] When the online spectrometer detects that the total RE content in the purified melt is less than 0.12 wt% or the weight ratio of La to Ce is less than 1.0, Al and La, Ce, Sm, and Gd intermediate alloys are immediately added to the purified melt, while the shear rate is controlled at 300 s⁻¹. -1 When the online spectrometer detects that the Mg content in the semi-solid slurry is greater than 1.0 wt%, high-purity aluminum ingots are added and mixed, and the temperature of the semi-solid slurry is increased by 8°C.

[0096] (4) Rheological forming: Using extrusion casting equipment and preheating the mold to 300°C, the semi-solid slurry obtained in step (3) is injected into the preheated mold made of graphite-silicon nitride composite within 1.5s. Then, a pressure of 240MPa is applied and held for 5s. Then, the mold is cooled by introducing helium into the mold wall. First, 5MPa of helium is introduced for 5s, and then 2MPa of helium is introduced for 5s. After cooling, the mold is opened to obtain the billet.

[0097] (5) Post-processing: The blank obtained in step (4) is artificially aged at 190°C for 5 hours to obtain a high-strength and high-conductivity aluminum alloy electrical conductor material.

[0098] Comparative Example 1: Conventional 6201 alloy was continuously cast, rolled and drawn, then annealed at 230℃ for 4 hours, and then cold-drawn to obtain a rod blank with a diameter of 4 mm. The rod blank was then aged at 180℃ for 6 hours to obtain aluminum alloy electrical conductor material.

[0099] Experimental Example: Aluminum alloy electrical conductor materials were prepared according to the methods described in Examples 1-6 and Comparative Example 1. Commercially available aluminum alloy wires were used as a control. The performance of the obtained aluminum alloy electrical conductor materials was tested. A blank with a diameter of 10 mm was first made, aged, and then cold-drawn to obtain a conductor material with a diameter of 4 mm for testing. The specific results are shown in Table 1.

[0100] Table 1 Performance test results of aluminum alloy electrical conductor materials prepared by different methods

[0101]

[0102] Therefore, the aluminum alloy electrical conductor material prepared according to the method described in this invention has a tensile strength ≥320MPa, which is 35-45% higher than that of traditional 6201 continuously cast and rolled rods; a yield strength ≥260MPa, meeting the stringent requirements of a tension-to-weight ratio >10km for large-span, high-capacity overhead conductors of 500kV and above; and an electrical conductivity ≥58% IACS, which is 3-4% higher than that of 6201 aluminum alloy conductors; under the same current carrying capacity, the wire diameter can be reduced by 6-8%, saving more than 10% of aluminum material; at the same time, the strength retention rate at 230℃×1h is ≥90%, the upper limit of continuous use temperature is increased from 150℃ to 210℃, and the short-term accident temperature can reach 280℃, providing a material basis for double-capacity conductors and heat-resistant capacity expansion retrofits. In addition, the elongation is ≥10%, and there are no cracks after 8 bends, meeting the requirements of high-tension crimping and complex wiring construction.

[0103] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A high strength high conductivity aluminum alloy electrical conductor material characterized by: The aluminum alloy electric conductor material comprises the following components in percentage by weight: Si: 0.4%-0.8%, Mg: 0.5%-0.9%, Cu: 0.05%-0.2%, B: 0.01%-0.15%, Zr: 0-0.25%, rare earth elements: 0.15%-0.35%, total amount of other inevitable impurity elements: ≤0.15%, and the balance being aluminum; The weight ratio of Si and Mg is (0.8-1.2):1; The rare earth elements are composed of La, Ce, Sm and Gd, and the weight ratio of La and Ce is (1-2):1, the weight ratio of Sm and Gd is (1-2):1, and the weight ratio of Ce and Sm is (1-2):1; The microstructure of the aluminum alloy electrical conductor material includes equiaxed crystals of an α-Al matrix, Mg2Si phases, Al3Zr phases, and the following particles: Al 11 (La,Ce)3, Al2Si2(La,Ce,Sm,Gd), Al3Sm, Al3Gd.

2. The high strength, high conductivity aluminum alloy electrical conductor material of claim 1, wherein: The weight percentage of the B element is 0.05%-0.15%, and the weight percentage of the Zr element is 0.05%-0.2%.

3. The method of producing high-strength and high-conductivity aluminum alloy electrical conductor material according to any one of claims 1 to 2, characterized by: The preparation method comprises the following steps: (1) alloy smelting: aluminum ingots, copper ingots, magnesium ingots, silicon ingots and intermediate alloys composed of any two or more of Si, Mg, Cu, B, Zr, La, Ce, Sm and Gd are weighed according to the proportion as raw materials, and then the raw materials are mixed and smelted at 710-780 DEG C to obtain an intermediate melt; (2) melt purification: the intermediate melt obtained in step (1) is degassed by rotating spraying of argon with a purity of 99.9%, and then filtered to obtain a purified melt; (3) Preparation of thixotropic slurry: The purified melt obtained in step (2) is cooled to 610℃~650℃, and then a shear force is applied to the purified melt, with the shear rate controlled at 500s. -1 ~1200s -1 The application time is controlled within 30s to 60s. During the last 10s to 20s of the shear force treatment, Al-5Ti-1B alloy is added to the purified melt, and the weight of the added Al-5Ti-1B alloy is 0.05% of the weight of the purified melt. After applying shear force treatment to the purified melt, a rotating magnetic field is applied for 5s to 10s, and the intensity of the rotating magnetic field is 0.20T to 0.30T. Then a semi-solid slurry with a solid phase content of 15% to 25% is obtained, and the viscosity of the semi-solid slurry is 0.10Pa·s to 0.15Pa·s. When the online spectrometer detects that the total amount of RE in the purification melt is less than 0.12wt% or the weight ratio of La and Ce is less than 1.0, the intermediate alloy of Al and La, Ce, Sm, Gd is supplemented to the purification melt, and the shear rate is controlled at 300s -1 ~400s -1 When the online spectrometer detects that the Mg content in the semi-solid slurry is greater than 1.0wt%, high-purity aluminum ingot is added to mix and the temperature of the semi-solid slurry is increased by 5℃~8℃; (4) rheological forming: using an extrusion casting device, the semi-solid slurry obtained in step (3) is injected into a preheated mold within 0.5-1.5 s, then a pressure of 150-250 MPa is applied and the pressure is maintained for 5-10 s, then the mold is cooled and the cooling rate is controlled to be ≥50 DEG C / s, and after cooling, the mold is opened to obtain a blank; (5) post-treatment: the blank obtained in step (4) is artificially aged at 180-190 DEG C for 5-6 h to obtain a high-strength and high-conductivity aluminum alloy electric conductor material.

4. The method of claim 3, wherein: In step (2), the filtration adopts a two-stage filtration mode, first filtering the degassed intermediate melt with a ceramic filter with a porosity of 30 PPI, and then filtering the purified melt with a ceramic filter with a porosity of 50 PPI, wherein the hydrogen content in the purified melt is ≤0.12 mL / 100g.

5. The method of claim 3, wherein: In step (4), the mold is preheated to 250-300 DEG C before the semi-solid slurry is injected.

6. The method of claim 3, wherein: In step (4), helium is used to cool the mold, specifically by first treating with 5 MPa of helium for 2-3 s, and then treating with 2 MPa of helium for 3-5 s.

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