Rare earth modified high-strength torsion-resistant aluminum alloy cable and preparation method thereof

Abstract

The invention relates to the technical field of aluminum alloy cables, and provides a rare earth modified high-strength torsion-resistant aluminum alloy cable and a preparation method thereof, and the rare earth modified high-strength torsion-resistant aluminum alloy cable comprises the following components by mass percent: 0.31-0.34% of Si; 0.33%-0.38% of Fe; mg / Si, rare earth Re, Mn / Fe and Ni / Fe are controlled, and components such as Cu, Zr, Nb and B are optimized; and the balance of aluminum. The aluminum alloy wire has the advantages of high tensile strength, large elongation and high conductivity, and has no crack and distortion in a 1440-degree torsion experiment at normal temperature, and the wire fracture rate in the 1440-degree torsion experiment at 45 DEG C is less than 0.9%, so that the torsion-resistant aluminum alloy cable with better comprehensive performance is obtained.

Description

Technical Field

[0001] This application relates to the field of aluminum alloy cable technology, specifically to a rare earth modified high-strength torsion-resistant aluminum alloy cable and its preparation method. Background Art

[0002] Wind power inherently possesses irreplaceable characteristics and scalability, making it a crucial green energy source and a core component of renewable energy. Its installed capacity will increase significantly, with China already being the world's largest and fastest-growing wind power market, projected to exceed 300GW by 2022. The arrival of large-scale wind power projects and grid parity makes reducing the construction costs of infrastructure such as towers key drivers of industry development. As a critical component, cable cost optimization is of paramount importance.

[0003] Torsion-resistant wind power cables are widely installed in complex environments such as high temperature, high humidity, salt spray, and large temperature differences, where the cables undergo frequent torsion during operation. Therefore, the cables are required to possess characteristics such as high temperature resistance, corrosion resistance, and torsion resistance, and must be able to pass more than 10,000 cycles of torsion testing at room temperature (one cycle consists of a 1440° clockwise torsion followed by a return to the initial state, then a counter-clockwise torsion at the same angle followed by a return to the initial state) and 2,000 or 5,000 cycles of low-temperature torsion testing. With the advent of large-scale, grid-parity wind power, aluminum alloy cables replacing copper core cables in the tower's fixed sections have become a trend. However, the torsion sections currently still use copper core cables. Torsion-resistant cables are a crucial component, and currently, copper is the primary conductor in these cables. However, this presents several challenges: copper resources are scarce, international copper prices are high and volatile, and costs are uncontrollable. Copper has a high density (8.96 g / cm³), resulting in a significant self-weight for vertically installed cables within the tower. This not only increases the tower load but also severely degrades the cable's torsion resistance due to the stress generated by its immense weight. The tensile strength and elongation are still insufficient for the harsh operating conditions of frequent torsion in wind power.

[0004] Aluminum is abundant, inexpensive, and has a low density (2.7 g / cm³), excellent conductivity, and can achieve the dual goals of cost reduction (approximately 30%-50%) and weight reduction (approximately 60%). Using aluminum alloy conductors to replace copper conductors in the manufacture of torsion-resistant cables has promising application prospects. However, existing aluminum alloy conductors have low tensile strength and cannot effectively balance tensile strength and elongation performance. For example, in existing aluminum alloy products, the elongation of conductors with a tensile strength greater than 150 MPa drops sharply to 1%-2% (brittle state), and their high-temperature stability is insufficient. These factors are detrimental to the torsion resistance of the cable and cannot meet the requirements of torsion-resistant wind power cables installed in complex environments such as high temperature, high humidity, salt spray, and large temperature differences. Frequent torsion during operation necessitates high-temperature resistance, corrosion resistance, and torsion resistance, limiting the application prospects of aluminum alloy cables as torsion-resistant cables.

[0005] In the prior art, in order to adapt to the application of aluminum alloy cables as cables with torsion resistance, a soft aluminum alloy conductor for wind turbine tower torsion conductor and its preparation method are provided. The aluminum alloy conductor can be used in torsion applications, but it uses graphene sodium magnesium aluminum powder, which has high cost, high processing difficulty, and the composite powder is prone to agglomeration. When the conductor strength is improved, the toughness cannot meet the requirements. Repeated bending is prone to breakage. It is greatly affected by heat and has obvious problems such as a sharp drop in strength at high temperature.

[0006] The prior art provides a torsion-resistant aluminum alloy wind power cable, the main aluminum alloy formula comprising the following components by mass percentage: Si 0.4%-0.6%, Fe 0.1%-0.3%, Cu 0.02%-0.05%, Mn 0.01%-0.02%, Mg 0.35%-0.5%, Cr 0.01%-0.02%, Zn≤0.10%, B 0.01%-0.05%, Li 0.001%-0.005%, Zr 0.003%-0.01%, Sn 0.001%-0.005%, Sc 0.016%-0.02%; unreasonable composition design, such as excessive Si content, affects bending fatigue performance, electrical performance, and is not conducive to improving torsional performance; the tensile strength of the outermost aluminum alloy monofilament is 115-152MPa, and the elongation at break is ≥15%. The overall tensile strength and elongation at break fluctuate greatly, and the lack of consideration for insufficient conductivity, high temperature resistance and other deficiencies are not taken into account.

[0007] The existing technology provides a high-strength aluminum alloy Class 5 conductor for wind power torsion-resistant cables and its preparation method; the composition is: Si: 0.35-0.8 parts, Fe: 0.1-0.3 parts, Mg: 0.35-0.8 parts, B: 0.008-0.04 parts, Ni: 0.006-0.03 parts, Ce: 0.006-0.02 parts, La: 0.006-0.02 parts, Sc: 0.006-0.015 parts. The tensile strength of the single filament is ≥150 MPa; the elongation is ≥8%; and the conductivity is ≥50% IACS. While the tensile strength is improved, the elongation is affected, resulting in insufficient performance. The conductivity needs improvement, and high-temperature heat resistance is not considered.

[0008] As can be seen from the above, when aluminum alloy cables are used in torsion-resistant cables, there are problems such as mismatches in tensile strength, high-temperature resistance, high and low temperature torsion performance, elongation, conductivity, and unreasonable composition design. Therefore, this invention provides a rare-earth modified high-strength torsion-resistant aluminum alloy cable and its preparation method, which is used to prepare a torsion-resistant aluminum alloy cable with better overall performance. Summary of the Invention

[0009] To overcome the shortcomings of existing technologies, this application provides a rare earth-modified high-strength torsion-resistant aluminum alloy cable and its preparation method. The cable has a tensile strength ≥180 MPa, elongation ≥19%, conductivity ≥63% IACS, and exhibits no cracks or twisting in a 1440° torsion test at room temperature for 10,000 cycles. In a 1440° torsion test at 45°C for 15,000 cycles, the wire breakage rate is less than 0.9%, thus obtaining a torsion-resistant aluminum alloy cable with better overall performance.

[0010] The embodiments of this application are implemented as follows: This application provides an example of a rare-earth modified high-strength torsion-resistant aluminum alloy cable, composed of the following components by mass percentage: Si 0.31%-0.34%; Fe 0.33%-0.38%; Mg / Si = 0.65-0.91; Rare earth k = 0.19 - 0.28; The Mn / Fe ratio is 0.21-0.26; Ni / Fe is 0.12-0.18; Cu 0.06%-0.09%; Zr 0.06%-0.09%; Nb 0.08%-0.13%; B 0.002%-0.005%; The balance is aluminum.

[0011] Optionally, 0.12%≤Mn+Ni≤0.14%.

[0012] Optionally, where 0.15%≤Zr+Nb≤0.17%.

[0013] Optionally, the rare earth element Re includes La, Ce, and Er; where Er accounts for 20-30% of the total mass of Zr+Nb.

[0014] Optionally, the tensile strength is ≥180 MPa; the elongation is ≥19%; the conductivity is ≥63% IACS; no cracks or twisting are observed in the 1440° torsion test at room temperature for 10,000 cycles; and the wire breakage rate is less than 0.9% in the 1440° torsion test at 45°C for 15,000 cycles.

[0015] Optionally, the precipitated particles on the surface of the aluminum alloy wire are detected by scanning electron microscopy, and the particle area ratio is... The number of precipitated particles was 0.007-0.15 per μm. 2 The aluminum alloy wire has no air bubbles on its surface.

[0016] On the other hand, a method for preparing a rare-earth modified high-strength torsion-resistant aluminum alloy cable is provided. The method for preparing the aforementioned rare-earth modified high-strength torsion-resistant aluminum alloy cable includes: (1) Select industrial pure aluminum ingots, Si source, Fe source, Mg source, rare earth source, Mn source, Ni source, Cu source, Zr source, Nb source and B source as raw materials and mix them according to the design composition; (2) Heat and melt industrial pure aluminum at 710℃-750℃, add the above raw materials, and stir thoroughly after melting to make the composition of the aluminum alloy liquid uniform. (3) The aluminum alloy liquid is refined in the furnace to remove gas and impurities. At a high temperature of 730℃-740℃, a large argon flow rate of 33-38L / min is used for stirring. At a low temperature of 705℃-715℃, a small argon flow rate of 18-21L / min is used for stirring to facilitate deep hydrogen removal. Then, it is allowed to stand for 35-55 minutes to remove slag. (4) Continuous casting and rolling, with a rolling temperature of 560℃-570℃, continuously casting and rolling into aluminum alloy round rods of 9-10mm; (5) The aluminum alloy round rod is subjected to solution treatment and aging treatment; (6) The aluminum alloy round rod is drawn into aluminum alloy wire and annealed to obtain rare earth modified high strength torsion resistant aluminum alloy cable with a wire diameter of 0.9-1.5mm.

[0017] Optionally, in step (3), before continuous casting and rolling, ultrasonic treatment is performed with an ultrasonic power of 10-13 kW and a frequency of 2-3 kHz.

[0018] Optionally, in step (5), the aluminum alloy round rod is solution-treated at a low temperature of 540℃-560℃ for 40-55h, and then aged at a low temperature of 310℃-330℃ for 67-77h.

[0019] Optionally, in step (6), annealing is performed at 170℃-190℃.

[0020] Beneficial effects include: 1. This invention employs a high Fe, high Si, and low Mg / Si composition. Considering the solid solution strengthening of Mg and Si components, the amount of rare earth added is strictly controlled based on the content of some Si and high iron. This allows for strict control of the rare earth-refined strengthening composition design, thereby achieving a tensile strength ≥180 MPa; elongation ≥19%; conductivity ≥63% IACS. No cracks or twisting are observed in the 1440° torsion test at room temperature for 10,000 cycles, and the wire breakage rate is less than 0.9% in the 1440° torsion test at 45°C for 15,000 cycles. This results in a torsion-resistant aluminum alloy cable with superior overall performance.

[0021] 2. By adding Mn, whose content is primarily determined by the Fe content, it helps to compete with Fe to a certain extent, generating a more favorable precipitated phase. This reduces the potential adverse effects of high Fe and Si content, especially eliminating the possibility of Fe excess and reducing the chance of excess free Fe elements forming harmful blocky β-AlFeSi phases. This achieves the goal of improving tensile strength, heat resistance, and torsional resistance. Limiting the Mn / Fe ratio essentially considers the competitive relationship between Mn and Fe. Controlling the Ni / Fe ratio, by appropriately matching the amount of Fe added, mainly aims to enhance the role of nickel in forming the high-temperature strengthening phase of the AlFeNi composite, avoiding excessive addition that forms the AlNi composite phase (which has deteriorating properties). Too high a Ni / Fe ratio leads to the formation of the AlNi composite phase, while too low a Ni / Fe ratio results in insufficient formation of the high-temperature strengthening phase of the AlFeNi composite, both of which are detrimental to improving heat resistance, especially torsional resistance at high temperatures. Copper is a fundamental strengthening element in aluminum alloys. It dissolves into the aluminum alloy to form the θ (Al₂Cu) phase, which provides both solid solution strengthening and dispersion strengthening. This improves the tensile strength, yield strength, and heat resistance of the conductor, and is beneficial for enhancing high-temperature torsional resistance. Adding higher amounts of Zr and Nb to high-tensile-strength torsion-resistant conductors further enhances both tensile strength and heat and torsional resistance.

[0022] 3. At a high temperature of 730℃-740℃, a large argon flow rate of 33-38 L / min is used for stirring to facilitate the rapid floating of large inclusions, removing slag, impurities, and preliminary degassing. At a low temperature of 705℃-715℃, a small argon flow rate of 18-21 L / min is used for stirring to facilitate deep hydrogen removal and the removal of small inclusions. Lowering the temperature helps reduce the formation of new inclusions such as oxidation. The small flow rate produces smaller bubbles with a larger surface area, which is conducive to more efficient adsorption of residual hydrogen atoms and micron-sized or even submicron-sized fine inclusions in the melt and brings them to the liquid surface. This helps to increase the residual amount of melt gas, especially hydrogen, and to purify the melt, reduce the nuclei formed during later solidification, reduce bubbles on the surface of the conductor, refine grains, refine precipitated phases, and further improve tensile strength and torsional resistance.

[0023] 4. The formation of more fine precipitated particles on the surface of aluminum alloy wire reduces the possibility of crack formation and is more conducive to improving tensile strength and torsional resistance. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0026] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The term “and / or” as used herein includes all or any unit and all combinations of one or more associated listed items. Unless otherwise specified, all materials used herein are commercially available products. Performance testing, unless otherwise specified, can be performed according to national or industry standards.

[0027] When aluminum alloy cables are used in torsion-resistant cables, there are problems such as mismatches in tensile strength, high-temperature resistance, high and low temperature torsion performance, elongation, conductivity, and unreasonable composition design. Therefore, this invention provides a rare-earth modified high-strength torsion-resistant aluminum alloy cable and its preparation method.

[0028] The features and performance of this application will be further described in detail below with reference to embodiments: This invention provides a rare-earth modified high-strength torsion-resistant aluminum alloy cable, composed of the following components by mass percentage: Si 0.31%-0.34%; Fe 0.33%-0.38%; Mg / Si = 0.65-0.91; Rare earth k = 0.19 - 0.28; The Mn / Fe ratio is 0.21-0.26; Ni / Fe is 0.12-0.18; Cu 0.06%-0.09%; Zr 0.06%-0.09%; Nb 0.08%-0.13%; B 0.002%-0.005%; The balance is aluminum.

[0029] Optionally: 0.12% ≤ Mn + Ni ≤ 0.14%; Optionally, 0.15% ≤ Zr + Nb ≤ 0.17%; Optionally, the rare earth element Re includes lanthanum (La), cerium (Ce), and erbium (Er); wherein erbium (Er) accounts for 20-30% of the total mass of Zr+Nb.

[0030] Understandably, aluminum alloys contain many components, each with a different function. Although the individual functions of each element are well understood, the interactions between them remain largely unknown. To avoid the influence of different elements, this invention adds less or no elements not involved in the process, such as Cr, Zn, Li, Sn, Sc, Ca, Be, Co, Mo, Ga, V, K, Na, Sr, Ti, Rb, Pd, and Ag. This helps reduce costs while avoiding the unpredictable impact of adding these elements on performance.

[0031] This invention employs a high Fe, high Si, and low Mg / Si composition. After considering solid solution strengthening of the Mg and Si components, the amount of rare earth elements added is strictly controlled based on the content of some Si and high iron. This strict control of the rare earth-refined strengthening composition design results in a tensile strength ≥180 MPa, elongation ≥19%, conductivity ≥63% IACS, and no cracks or twisting observed in a 1440° torsion test at room temperature for 10,000 cycles. Furthermore, the wire breakage rate is less than 0.9% in a 1440° torsion test at 45°C for 15,000 cycles, resulting in a torsion-resistant aluminum alloy cable with superior overall performance.

[0032] The addition of high-iron content allows for the formation of submicron-sized, fine, and regular Al3Fe and Al6Fe precipitates with aluminum, resulting in higher alloy strength, improved heat resistance, increased single-wire elongation, and enhanced torsional resistance under high-strength conditions. However, the Fe content cannot be too high; exceeding the aforementioned components will significantly reduce the electrical properties of the conductor. The Fe content must also not be below the specified range; below this range, it is detrimental to improving conductor strength and hinders the formation of composite reinforcing phases with Si and rare-earth Re, thus failing to effectively improve conductor performance. Suitable Fe content options include 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, and 0.38%.

[0033] The addition of high silicon content allows Mg to react with Si, forming the Mg2Si reinforcing phase, which enhances the tensile strength of aluminum alloy conductors, especially at high temperatures, thus improving the conductor's torsional resistance at high temperatures. Simultaneously, the high silicon content design improves corrosion resistance and increases the elongation of the aluminum alloy. However, if the Si content exceeds the aforementioned range, it will reduce electrical properties, fatigue bending performance, and tensile properties, affecting the improvement of torsional resistance. If the Si content is below the aforementioned range, it is not conducive to achieving high tensile strength and improving the conductor's torsional resistance at high temperatures. Therefore, by using a high-silicon design in high-speed rail, Fe is encouraged to form the AlFeSi phase (e.g., β-Al5FeSi) with Si and Al, which can significantly improve the conductor's tensile strength, especially at high temperatures, and facilitate the improvement of the conductor's torsional resistance at high temperatures.

[0034] The addition of magnesium, due to its large atomic radius, can generate more lattice distortion, achieving solid solution hardening and uniform distribution of fine, dispersed particles in the conductor crystal. This is beneficial for obtaining a fine and uniform crystal structure, as well as the precipitation of fine, uniform dispersed particles within or at the boundaries of the crystal structure. Magnesium also improves the corrosion resistance and heat resistance of aluminum alloys. Improved corrosion resistance further reduces surface defects in the conductor, especially crack formation (crack formation will be significantly amplified during torsion, leading to reduced torsional performance), thus improving torsional resistance. However, excessive magnesium addition may lead to increased electrical resistance, reduced heat resistance, and the formation of an excessive Mg2Si strengthening phase with Si, resulting in higher brittleness and reduced elongation. This can cause performance degradation during heat treatment; for example, during aging treatment, Mg and Si atoms tend to precipitate more at grain boundaries, forming precipitation-free zones (PFZs) and coarse grain boundary Mg2Si phases, becoming natural sources of cracks. Furthermore, its high thermal instability leads to a severe decrease in torsional resistance under repeated tensile and torsional stresses. Therefore, with Mg / Si = 0.65-0.91 (selectable values ​​include 0.65, 0.68, 0.71, 0.74, 0.76, 0.79, 0.83, 0.85, 0.87, 0.88, 0.89, 0.91, etc.), a low-magnesium design is adopted, strictly limiting the ratio of Mg to Si to a lower level. This allows for an excess of silicon, which is beneficial for the combined effects of silicon, aluminum, and iron, as well as their combined effects with rare earth elements and other elements. This makes the formation of the Mg2Si strengthening phase more controllable, avoids excessive formation, and facilitates the role of magnesium in improving the corrosion resistance, heat resistance, and torsional resistance of aluminum alloys.

[0035] Rare earth elements have very low solid solubility in aluminum. When a small amount of rare earth elements is added, exceeding the solid solubility limit in the aluminum matrix, the excess rare earth elements will combine with other elements (such as Fe and Si) or themselves, resulting in rich rare earth intermetallic compounds. For example, some Fe in the alloy precipitates as Al3Fe and Al6Fe, some Fe forms AlFeRE compounds with RE, and some Fe forms AlSiFeRE compounds with RE. Previously, aluminum alloy systems containing Mg and silicon primarily used Mg2Si strengthening phases to improve performance, but this has the aforementioned adverse effects. When using a low-Mg design with Mg / Si = 0.65-0.91, a high-iron, high-silicon design promotes the formation of AlFeSi phases (e.g., β-Al5FeSi) with Fe, Si, and Al, which can significantly improve the tensile strength of the conductor, especially at high temperatures, and improve the torsional resistance of the conductor at high temperatures. However, the AlFeSi phase formed by Fe, Si, and Al is prone to forming plate-like or needle-like structures, which are brittle phases and detrimental to performance optimization. By adding rare earth elements (such as Ce), rare earth elements can enhance the performance of rare earth elements (such as Ce, Si, Fe, Si, and Al). Rare earth elements (such as La and Er) react strongly with elements like Fe and Si, transforming the lamellar / acicular β-Al₅FeSi phase into fine, spherical (Al,Fe,Si,RE) multi-component compound phases. These fine, hard, and uniformly distributed spherical phase particles act as a strong barrier to dislocation movement, significantly improving the tensile strength of the alloy. Furthermore, they have a strong grain-refining effect, enhancing the uniformity of precipitate distribution. The fine, hard, and uniformly distributed spherical phase particles also exhibit extremely high thermal stability, greatly eliminating stress concentration effects and making crack initiation difficult, thus significantly improving torsional resistance, especially high-temperature torsional resistance. In other words, by adopting a low-magnesium, high-iron, and high-silicon design with a Mg / Si ratio of 0.65-0.91, and by adding an appropriate amount of rare earth elements, the proportion of fine, spherical (Al,Fe,Si,RE) multi-component compound phases is increased while simultaneously generating Mg₂Si for strengthening. This is beneficial for improving the tensile strength of the conductor, especially at high temperatures, and for enhancing the torsional resistance of the conductor at high temperatures.

[0036] Because rare earth elements have very low solid solubility in aluminum, excessive amounts can lead to deterioration of conductor performance. For example, excessive addition of rare earth elements, combined with other elements (such as Fe and Si) or with themselves, can form more coarse, blocky rare earth-rich intermetallic compounds, such as Al4Ce and Al8Cu4Ce, which can become crack initiation sites and significantly affect torsional resistance. With k=0.19-0.28, the study found that solid solution strengthening of Mg and Si components consumes some Si. The introduction of rare earth elements is actually to consider the effect of solid solution strengthening of Mg and Si components on the bonding of rare earth elements with Fe and Si (in fact, some Si interacts with rare earth elements, and the corresponding proportion can be obtained by summarizing a large amount of production data). By linking the addition of rare earth elements with the content of some Si and high iron, the amount of rare earth elements added is strictly controlled, thereby regulating the proportion of rare earth elements forming precipitates with Al, Fe and Si, and thus strictly controlling the refining and strengthening effect of rare earth elements. Adding an appropriate amount of rare earth elements can generate a suitable proportion of fine, spherical (Al, Fe, Si, RE) multi-component compound phases while generating Mg2Si strengthening. At the same time, rare earth elements have a greater affinity for elements such as hydrogen than aluminum. By strictly controlling the addition of rare earth elements, it is beneficial to reduce the residual bubbles on the surface of aluminum alloy wires after preparation (mainly caused by the retention of gases such as hydrogen, which will become the starting point of subsequent cracks and affect the improvement of torsional resistance). This is beneficial to improving the tensile strength of the wires, especially the tensile strength at high temperatures, and also beneficial to improving the torsional resistance of the wires at high temperatures.

[0037] The addition of manganese (Mn) results in MnAl4, which combines with aluminum and has a similar potential to pure aluminum, thus improving corrosion resistance. As a high-temperature strengthening phase, manganese enhances the solid solution strengthening and supplementary strengthening of aluminum alloys (achieved by increasing the recrystallization temperature to refine recrystallized grains through the formation of dispersed MnAl6 compound particles) and improves heat resistance. Furthermore, the addition of Mn reduces the adverse effects of Fe and Si. This is primarily because Mn promotes the formation of finer, spherical α-Al(FeMn)Si phases, significantly reducing crack initiation sites. Under high-iron and high-silicon conditions, adding Mn, with its content determined mainly by the Fe content, helps to compete with Fe to a certain extent, generating more favorable precipitates. This reduces the potential adverse effects of high Fe and Si content, especially eliminating the possibility of Fe excess and reducing the chance of excess free Fe forming harmful blocky β-AlFeSi phases. This ultimately improves tensile strength, heat resistance, and torsional resistance. The Mn / Fe ratio is 0.21-0.26, optionally 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, etc. By limiting the Mn / Fe ratio, the competitive relationship between Mn and Fe is considered. The proportion of Mn added relative to the Fe content cannot be too high. Excessive manganese addition will over-substitute the role of Fe, and excessive manganese addition will lead to larger precipitate particle size (e.g., coarse composite phases with high Mn and Fe content, reducing the precipitation of beneficial AlFeSi and AlFeMnSi composite phases). Mn is prone to segregation, affecting the uniformity of composition and deteriorating the improvement of tensile strength and torsional resistance. The proportion of Mn added relative to the Fe content cannot be too low. Too low a ratio is not conducive to reducing the adverse effects of Fe and Si, and is not conducive to improving performance.

[0038] The addition of nickel facilitates the formation of a high-temperature strengthening phase in the AlFeNi composite, which is distributed as a fine, dispersed phase at the matrix grain boundaries. This phase exhibits thermal stability at high temperatures and strongly pins grain boundaries and dislocations, increasing the proportion of the heat-resistant phase in the fine, dispersed precipitates. This enhances the stability of the aluminum alloy crystal structure, thereby improving heat resistance, especially torsional resistance at high temperatures. The Ni / Fe ratio is 0.12-0.18, with selectable values ​​of 0.12, 0.12, 0.14, 0.15, 0.16, 0.17, and 0.18. Appropriate matching of the relative amount of Fe added aims to enhance the formation of the high-temperature strengthening phase in the AlFeNi composite, while avoiding excessive addition which leads to the formation of an AlNi composite phase (which degrades performance). An excessively high Ni / Fe ratio results in the formation of an AlNi composite phase, while an excessively low Ni / Fe ratio results in insufficient formation of the high-temperature strengthening phase, both of which are detrimental to improving heat resistance, especially torsional resistance at high temperatures.

[0039] Optionally, manganese and nickel, as added elements that significantly interact with Fe, are further limited to 0.12%≤Mn+Ni≤0.14%; that is, the total amount of manganese and nickel added is limited to avoid excessive addition, thereby preventing the addition of manganese and nickel from affecting the beneficial effects of high Fe and Si.

[0040] Copper is a fundamental strengthening element in aluminum alloys. It dissolves into the aluminum alloy to form the θ (Al₂Cu) phase, which provides both solid solution strengthening and dispersion strengthening. This improves the tensile strength, yield strength, and heat resistance of the conductor, and is beneficial for enhancing high-temperature torsional resistance. The Cu content is 0.06%-0.09%, with options including 0.06%, 0.07%, 0.08%, and 0.09%. Contents higher than these ranges affect the achievement of high electrical conductivity; contents lower than these ranges are detrimental to improving tensile strength and torsional resistance.

[0041] Adding Zr to aluminum alloys significantly improves tensile strength and heat resistance. Zirconium atoms have a larger atomic radius than aluminum, resulting in a higher diffusion activation energy in aluminum. This facilitates the formation of stable nanoscale Al3Zr precipitates, which pin dislocations and grain boundaries, enhancing tensile strength. Even at high temperatures, Zr effectively pins dislocations and grain boundaries, hindering deformation and intragranular and grain boundary slip. Furthermore, the precipitates are more stable during heat treatment and less prone to coarsening, thus improving heat resistance. Adding higher amounts of Zr to high-tensile-strength, torsion-resistant wires is beneficial for achieving high tensile strength and excellent heat and torsional resistance. The optimal Zr content is 0.06%-0.09%, with options including 0.06%, 0.07%, 0.08%, and 0.09%. Contents below these ranges are not conducive to improving nanoscale precipitates and heat resistance, while excessive Zr can lead to brittle Zr-containing precipitates, both of which negatively impact tensile strength and torsional resistance.

[0042] Niobium (Nb) can precipitate nanoscale high-temperature dispersed phases such as AlNb3, AlNb, and Al3Nb, exhibiting high thermal stability. It pins dislocations and grain boundaries, improving tensile strength. Even at high temperatures, it effectively pins dislocations and grain boundaries, hindering deformation and intragranular and grain boundary slip. Furthermore, the precipitated phases are more stable during heat treatment and less prone to coarsening, thus improving heat resistance. Adding a higher amount of Zr to high-tensile-strength torsion-resistant wires is beneficial for obtaining high tensile strength and heat and torsion resistance. The recommended Nb content is 0.08%-0.13%; options include 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, and 0.13%. Contents below these ranges are not conducive to improving nanoscale precipitates and heat resistance, while excessive Nb can lead to brittle Nb-containing precipitates, both of which are detrimental to improving tensile strength and torsion resistance.

[0043] Optionally, Zr and Nb can be used as particles to improve heat resistance, and the ratio can be: 0.15%≤Zr+Nb≤0.17%. It is necessary to control the total amount of both to avoid excessive addition, which would lead to the aggregation and growth of nano-precipitates, which would not be conducive to improving tensile strength and torsional resistance.

[0044] Optionally, rare earth Re includes lanthanum (La), cerium (Ce), and erbium (Er); among which erbium (Er) accounts for 20-30% of the total mass of Zr+Nb. Er is a common additive element to improve thermal conductivity in heat-resistant and conductive alloys, but there are no reports on how to properly add it to optimize performance in high-strength torsion-resistant aluminum alloys. Rare earth element Er promotes the precipitation of solute atoms, reduces lattice distortion, and improves conductivity. The combined effect of Er with Nb and Zr can promote the formation of highly thermally stable Al3(Nb, Zr) particles and the formation of suitable fine nanoscale precipitates. In high-strength torsion-resistant aluminum alloys, heat resistance is not the primary consideration. However, improving torsion resistance is necessary. During the torsion process of the wire, frictional heat generation and local torsion heat generation of internal particles are increased. By adding a relatively low amount of Er compared to that in heat-resistant aluminum alloys, the precipitation of highly thermally stable Al3(Nb, Zr) particles with appropriate particle size and quantity is promoted, which effectively solves the problem of improving the torsion resistance of high-strength torsion-resistant aluminum alloys. At the same time, it also helps to improve conductivity. By controlling the erbium (Er) content, the remaining components are mainly lanthanum (La) and cerium (Ce). These elements are relatively easy to obtain and have low cost, which helps to reduce the cost of the alloy. At the same time, the deep modification effect of La and Ce ensures that all coarse, sharp, brittle phases (especially β-AlFeSi) are completely eliminated, preventing the initiation of fatigue cracks from the root. It also has a better dehydrogenation effect, which is conducive to controlling the grain size to a suitable micron size and eliminating dendritic structure. This is beneficial to improving tensile strength, elongation, electrical conductivity and torsional resistance.

[0045] B is added to purify the melt, especially to purify the influence of non-added components from raw materials such as Ti, V, and Cr, and to further reduce their content to trace amounts (which can be called no added or no corresponding components), thereby improving performance. Since Ti, V, Cr, etc. are not actively added, B is added at an extremely low amount of 0.002%-0.005%.

[0046] On the other hand, a method for preparing a rare-earth modified high-strength torsion-resistant aluminum alloy cable is provided, comprising the following steps: (1) Industrial pure aluminum ingots, Si source, Fe source, Mg source, rare earth source, Mn source, Ni source, Cu source, Zr source, Nb source and B source are selected as raw materials and formulated according to the design composition; Si source, Fe source, Mg source, rare earth source, Mn source, Ni source, Cu source, Zr source, Nb source and B source are not specifically limited, and existing commonly used raw materials are selected and adjusted in consideration of cost and other requirements.

[0047] (2) Heat and melt industrial pure aluminum at 710℃-750℃, add the above raw materials, and stir thoroughly after melting to make the composition of the aluminum alloy liquid uniform. (3) The aluminum alloy liquid is subjected to in-furnace refining, degassing and impurity removal treatment. At a high temperature of 730℃-740℃, a large argon flow rate of 33-38L / min is used for stirring to facilitate the rapid floating of large inclusions, slag removal, impurity removal and preliminary degassing. At a low temperature of 705℃-715℃, a small argon flow rate of 18-21L / min is used for stirring to facilitate deep hydrogen removal and removal of small inclusions. Lowering the temperature is conducive to reducing new inclusions such as oxidation. The small flow rate produces smaller bubbles with a larger surface area, which is conducive to more efficient adsorption of residual hydrogen atoms and micron-sized or even submicron-sized fine inclusions in the melt and bringing them to the liquid surface. This is conducive to increasing the residual amount of melt gas, especially hydrogen, and to purifying the melt, reducing the nuclei of later solidification precipitation, which is conducive to reducing bubbles on the surface of the conductor, refining the grains, refining the precipitated phase, and further improving the tensile strength and torsional resistance. After standing for 35-55 minutes to remove slag, ultrasonic treatment is performed before continuous casting and rolling. The ultrasonic power is 10-13 kW and the frequency is 2-3 kHz. Through high-power ultrasonic treatment, the precipitates in the middle of the melt are broken up, thereby forming finer dispersed precipitates. This is beneficial for reducing or avoiding the generation of large precipitates during the later solidification process under high Fe and high Si conditions, and is also beneficial for improving tensile strength and torsional resistance.

[0048] (4) Continuous casting and rolling, with a rolling temperature of 560℃-570℃, continuously casting and rolling into aluminum alloy round rods of 9-10mm; (5) The aluminum alloy round rod is solution-treated at 540℃-560℃ for 40-55h, and then aged at 310℃-330℃ for 67-77h. Through longer low-temperature solution-treatment and low-temperature aging, recrystallization and grain coarsening are effectively suppressed, fine-grained structure is maintained, grain coarsening is avoided, more uniform dispersion of nano-dispersed phase is promoted, the risk of cracks generated in later torsion processes is reduced, and tensile strength and toughness are avoided, thus affecting torsional performance.

[0049] (6) The aluminum alloy round rod is drawn into an aluminum alloy wire, and finally annealed at 170℃-190℃ to obtain a rare earth modified high-strength torsion-resistant aluminum alloy cable with a wire diameter of 0.9-1.5mm. It should be noted that the rare earth modified high-strength torsion-resistant aluminum alloy cable here specifically refers to aluminum alloy conductors and cables without insulation layers or the like.

[0050] Sampling was performed on the aluminum alloy wire prepared by the above method (on its cross-section). Scanning electron microscopy (SEM) images were obtained of different regions (e.g., a 60 μm region on the surface of the aluminum alloy wire) containing precipitated particles (including constituent particles, intermetallic particles, oxides, deposits, or hardened particles, etc.). A uniform field of view (45 μm long and 80 μm wide) was selected. The area and number of precipitated particles were statistically analyzed to obtain the particle area ratio (particle area / field of view). The number of precipitated particles was 0.007-0.15 per μm. 2 The aluminum alloy wire surface is free of bubbles. Preferably, the particle area ratio (particle area / field of view) is: The number of precipitated particles was 0.12-0.14 per μm. 2 Therefore, the formation of more fine precipitate particles on the surface of aluminum alloy wire reduces the possibility of crack formation and is more conducive to improving tensile strength and torsional resistance.

[0051] Example 1 A rare-earth modified high-strength torsion-resistant aluminum alloy cable is composed of the following components by weight percentage: Si 0.33%, Fe 0.37%, Mg 0.23% (Mg / Si=0.71), rare earth Re 0.11% (of which rare earth) The rare earth elements (re) include lanthanum (La), cerium (Ce), and erbium (Er); Er is 0.04%, of which erbium (Er) accounts for 28% of the total mass of Zr+Nb, with the remainder being aluminum.

[0052] The method for preparing the above-mentioned aluminum alloy cable is as follows: A method for preparing a rare earth modified high-strength torsion-resistant aluminum alloy cable includes the following steps: (1) Select industrial pure aluminum ingots, Si source, Fe source, Mg source, rare earth source, Mn source, Ni source, Cu source, Zr source, Nb source and B source as raw materials and mix them according to the designed composition.

[0053] (2) Heat and melt industrial pure aluminum at 735℃-750℃, add the above raw materials, and stir thoroughly after melting to make the composition of the aluminum alloy liquid uniform. (3) The aluminum alloy liquid was subjected to in-furnace refining, degassing and impurity removal treatment at 735℃-740℃ with an argon flow rate of 35L / min; at 710℃-715℃ with an argon flow rate of 19L / min. After that, it was allowed to stand for 45 minutes to remove slag. Before continuous casting and rolling, it was subjected to ultrasonic treatment with an ultrasonic power of 12Kw and a frequency of 2.4KHz.

[0054] (4) Continuous casting and rolling, with a rolling temperature of 565℃, to continuously cast and roll aluminum alloy round rods of 9mm; (5) The aluminum alloy round rod was solution-treated at 557℃ for 53 hours, and then aged at 328℃ for 71 hours. (6) The aluminum alloy round rod is drawn into an aluminum alloy wire and then annealed at 187°C to obtain a rare earth modified high-strength torsion-resistant aluminum alloy cable with a wire diameter of 1.2 mm.

[0055] Performance tests are as follows: tensile strength 191 MPa; elongation 23%; electrical conductivity 65% ​​IACS; no cracks or twisting observed in 1440° torsion tests at room temperature for 10,000 cycles; wire breakage rate of 0.40% in 1440° torsion tests at 45°C for 15,000 cycles; scanning electron microscopy results: particle area ratio... The number of precipitated particles was 0.13446 / μm. 2 All the above tests are average values ​​from multiple samples.

[0056] Example 2: The composition and preparation method of the rare earth modified high-strength torsion-resistant aluminum alloy cable in Example 1 are basically the same, except that: Mn is 0.09% and Mn+Ni=0.15%; Performance tests are as follows: tensile strength 193 MPa; elongation 22%; electrical conductivity 65% ​​IACS; no cracks or twisting observed in 1440° torsion tests at room temperature for 10,000 cycles; wire breakage rate of 0.44% in 1440° torsion tests at 45°C for 15,000 cycles; scanning electron microscopy results: particle area ratio... The number of precipitated particles was 0.12667 / μm.2 Comparing Examples 1 and 2, it can be seen that the contents of Mn and Ni are relatively high, and the amount of Mn added is high. Based on the competitive relationship between Mn and Fe, Mn is beneficial to improving tensile strength, but it is detrimental to the improvement of properties such as the wire breakage rate in the 1440° torsion test at 45° under 15,000 cycles.

[0057] Example 3: The composition and preparation method of the rare earth modified high-strength torsion-resistant aluminum alloy cable in Example 1 are basically the same, except that: Zr 0.09%, Nb 0.13%, Zr+Nb=0.22%; Performance tests are as follows: tensile strength 185 MPa; elongation 21%; electrical conductivity 65% ​​IACS; no cracks or twisting observed in 1440° torsion tests at room temperature for 10,000 cycles; wire breakage rate of 0.52% in 1440° torsion tests at 45°C for 15,000 cycles; scanning electron microscopy results: particle area ratio... The number of precipitated particles was 0.11112 / μm. 2 Comparing Examples 1 and 3, it can be seen that as the sum of Zr and Nb increases, the particle area ratio increases and the number of precipitated particles decreases, which leads to the aggregation and growth of nano-precipitated phases, which is not conducive to improving tensile strength and torsional resistance.

[0058] Example 4: The composition and preparation method of the rare earth modified high-strength torsion-resistant aluminum alloy cable in Example 1 are basically the same, except that: Zr 0.06%, Nb 0.08%, Zr+Nb=0.14%; Performance tests are as follows: tensile strength 178 MPa; elongation 20%; electrical conductivity 64% IACS; no cracks or twisting observed in 1440° torsion tests at room temperature for 10,000 cycles; wire breakage rate of 0.54% in 1440° torsion tests at 45°C for 15,000 cycles; scanning electron microscopy results: particle area ratio... The number of precipitated particles was 0.10011 / μm. 2 Comparing Examples 1 and 4, it can be seen that the sum of Zr and Nb decreases, the particle area ratio decreases, the number of precipitated particles decreases, and the generation of nano-precipitates decreases, which is not conducive to improving tensile strength and torsional resistance.

[0059] Example 5: The composition and preparation method of the rare earth modified high-strength torsion-resistant aluminum alloy cable in Example 1 are basically the same, except that Er is 0.02%; Performance tests are as follows: tensile strength 183 MPa; elongation 22%; electrical conductivity 65% ​​IACS; no cracks or twisting observed in 1440° torsion tests at room temperature for 10,000 cycles; wire breakage rate of 0.46% in 1440° torsion tests at 45°C for 15,000 cycles; scanning electron microscopy results: particle area ratio... The number of precipitated particles was 0.12676 / μm. 2 Comparing Example 1 and Example 5, it can be seen that a lower Er content results in a smaller particle area ratio, a reduced number of precipitated particles, and a decrease in the generation of nano-precipitates, which is detrimental to improving tensile strength and torsional resistance.

[0060] Example 6: The composition and preparation method of the rare earth modified high-strength torsion-resistant aluminum alloy cable in Example 1 are basically the same, except that it does not contain Er. Performance tests are as follows: tensile strength 171 MPa; elongation 20%; electrical conductivity 62% IACS; no cracks or twisting observed in 1440° torsion tests at room temperature for 10,000 cycles; wire breakage rate of 0.58% in 1440° torsion tests at 45°C for 15,000 cycles; scanning electron microscopy results: particle area ratio... The number of precipitated particles was 0.11981 / μm. 2 Comparing Examples 1 and 6, it can be seen that without Er, the particle area ratio increases and the number of precipitated particles decreases, resulting in the aggregation and growth of nano-precipitates, which is not conducive to improving tensile strength and torsional resistance.

[0061] Example 7: The composition and preparation method of the rare earth modified high-strength torsion-resistant aluminum alloy cable in Example 1 are basically the same, except that Er is 0.08%; Performance tests are as follows: tensile strength 189 MPa; elongation 23%; electrical conductivity 65% ​​IACS; no cracks or twisting observed in 1440° torsion tests at room temperature for 10,000 cycles; wire breakage rate of 0.42% in 1440° torsion tests at 45°C for 15,000 cycles; scanning electron microscopy results: particle area ratio... The number of precipitated particles was 0.14708 / μm. 2 Comparing Examples 1 and 7, it can be seen that with a higher Er content, the particle area ratio does not change much, the number of precipitated particles increases, and the size of the resulting nano-precipitated phase decreases, which is not conducive to improving tensile strength and torsional resistance.

[0062] Example 8: The composition and preparation method of the rare earth modified high-strength torsion-resistant aluminum alloy cable in Example 1 are basically the same, except that ultrasonic treatment is not used in the preparation method. Performance tests are as follows: tensile strength 167 MPa; elongation 19%; electrical conductivity 62% IACS; no cracks or twisting observed in 1440° torsion tests at room temperature for 10,000 cycles; wire breakage rate of 0.61% in 1440° torsion tests at 45°C for 15,000 cycles; scanning electron microscopy results: particle area ratio... The number of precipitated particles was 0.09157 / μm. 2 Comparing Examples 1 and 8, it can be seen that the preparation method did not employ ultrasonic treatment, which is not conducive to the formation of finer dispersed precipitates, and is not conducive to reducing or avoiding the generation of large precipitates during the later solidification process under high Fe and high Si conditions, thus reducing tensile strength and torsional resistance.

[0063] Example 9: The composition and preparation method of the rare earth modified high-strength torsion-resistant aluminum alloy cable in Example 1 are basically the same, except that the solution temperature is 600℃ and the aging temperature is 360℃ in the preparation method. Performance tests are as follows: tensile strength 161 MPa; elongation 18%; electrical conductivity 61% IACS; no cracks or twisting observed in 1440° torsion tests at room temperature for 10,000 cycles; wire breakage rate of 0.64% in 1440° torsion tests at 45°C for 15,000 cycles; scanning electron microscopy results: particle area ratio... The number of precipitated particles was 0.12001 / μm. 2 Comparing Examples 1 and 9, it can be seen that the solution temperature and aging temperature in the preparation method are relatively high, which is not conducive to promoting more uniform dispersion and precipitation of the nano-dispersed phase, increasing the risk of cracks in the later torsion process, and reducing tensile strength and torsional resistance.

[0064] Comparative Example 1 The composition and preparation method of the rare earth modified high-strength torsion-resistant aluminum alloy cable in Example 1 are basically the same, except that: Mg 0.43%; Performance tests are as follows: tensile strength 153 MPa; elongation 15%; electrical conductivity 60% IACS; no cracks or twisting observed in 1440° torsion tests at room temperature for 10,000 cycles; wire breakage rate of 0.51% in 1440° torsion tests at 45°C for 15,000 cycles; scanning electron microscopy results: particle area ratio... The number of precipitated particles was 0.09141 / μm. 2 Comparing Example 1 and Comparative Example 1, it can be seen that the Mg content was too high, with the Mg / Si ratio reaching 1.3, i.e., high Mg / Si. The precipitated particles were large, which significantly reduced the tensile strength and torsional resistance.

[0065] Comparative Example 2 The composition and preparation method of the rare earth modified high-strength torsion-resistant aluminum alloy cable in Example 1 are basically the same, except that Re is 0.3%; Performance tests are as follows: tensile strength 187 MPa; elongation 22%; electrical conductivity 64% IACS; no cracks appeared in the 1440° torsion test at room temperature for 10,000 cycles; the wire breakage rate was 0.74% in the 1440° torsion test at 45°C for 15,000 cycles; scanning electron microscopy results: particle area ratio... The number of precipitated particles was 0.13012 / μm. 2 Comparing Example 1 and Comparative Example 2, it can be seen that adding too much Re content results in larger precipitated particles, which significantly reduces torsional resistance.

[0066] Comparative Example 3 The composition and preparation method of the rare earth modified high-strength torsion-resistant aluminum alloy cable in Example 1 are basically the same, except that: no rare earth is added. Performance tests are as follows: tensile strength 135 MPa; elongation 17%; electrical conductivity 60% IACS. Cracks appeared during a 1440° torsion test at room temperature for 10,000 cycles. Scanning electron microscopy results show that the particle area ratio is... The number of precipitated particles was 0.07241 / μm. 2 Bubbles appeared on the surface of the aluminum alloy wire. Comparing Example 1 and Comparative Example 3, it can be seen that without the addition of Re, the precipitated particles are significantly larger, which significantly reduces the tensile strength, torsional resistance, conductivity, elongation and other properties.

[0067] Comparative Example 4 The composition and preparation method of the rare earth modified high-strength torsion-resistant aluminum alloy cable in Example 1 are basically the same, except that: Fe 0.12%; Performance tests were conducted as follows: tensile strength 161 MPa; elongation 17%; electrical conductivity 56% IACS; cracks appeared during a 1440° torsion test at room temperature for 10,000 cycles. Comparison of Example 1 and Comparative Example 4 shows that the Fe content was too low, i.e., the low Fe content design significantly reduced tensile strength, torsional resistance, elongation, and other properties.

[0068] Comparative Example 5 The composition and preparation method of the rare earth modified high-strength torsion-resistant aluminum alloy cable in Example 1 are basically the same, except that: Si 0.20%; Performance tests were conducted as follows: tensile strength 164 MPa; elongation 16%; conductivity 58% IACS; cracks appeared in a 1440° torsion test at room temperature for 10,000 cycles. Comparing Example 1 and Comparative Example 5, it is evident that the Si content was too low, i.e., the low Si content design significantly reduced tensile strength, torsional resistance, conductivity, elongation, and other properties.

[0069] Comparative Example 6 The composition and preparation method of the rare earth modified high-strength torsion-resistant aluminum alloy cable in Example 1 are basically the same, except that low-temperature low-argon gas flow treatment was not used. Performance tests are as follows: tensile strength 182 MPa; elongation 21%; electrical conductivity 64% IACS; no cracks or twisting observed in 1440° torsion tests at room temperature for 10,000 cycles; wire breakage rate of 0.67% in 1440° torsion tests at 45°C for 15,000 cycles; scanning electron microscopy results: particle area ratio... The number of precipitated particles was 0.12457 / μm. 2 Bubbles appeared on the surface of the aluminum alloy wire. Comparing Example 1 and Comparative Example 5, it can be seen that the preparation method did not use low-temperature, low-flow-rate argon treatment; the precipitated phase transformation was large, and bubbles appeared on the surface of the aluminum alloy wire, significantly reducing the torsional resistance.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rare-earth modified high-strength torsion-resistant aluminum alloy cable, characterized in that, It consists of the following components by weight percentage: Si 0.31%-0.34%; Fe 0.33%-0.38%; Mg / Si = 0.65-0.91; Rare earth k = 0.19 - 0.28; The Mn / Fe ratio is 0.21-0.26; Ni / Fe is 0.12-0.18; Cu 0.06%-0.09%; Zr 0.06％-0.09％； Nb 0.08%-0.13%; B 0.002％-0.005％； The balance is aluminum; of which, 0.12% ≤ Mn + Ni ≤ 0.14%; precipitated particles on the surface of the aluminum alloy wire were detected by scanning electron microscopy, and the particle area ratio was [missing information]. The number of precipitated particles was 0.007-0.15 per μm. 2 The aluminum alloy wire has no bubbles on its surface; rare earth Re includes La, Ce, and Er; among which Er accounts for 20-30% of the total mass of Zr+Nb.

2. The rare-earth modified high-strength torsion-resistant aluminum alloy cable according to claim 1, characterized in that, Among them, 0.15%≤Zr+Nb≤0.17%.

3. The rare-earth modified high-strength torsion-resistant aluminum alloy cable according to claim 1, characterized in that, Tensile strength ≥180MPa; elongation ≥19%; electrical conductivity ≥63%IACS; no cracks or twisting in 1440° torsion test at room temperature for 10,000 cycles; wire breakage rate less than 0.9% in 1440° torsion test at 45℃ for 15,000 cycles.

4. A method for preparing a rare-earth modified high-strength torsion-resistant aluminum alloy cable, comprising preparing a rare-earth modified high-strength torsion-resistant aluminum alloy cable as described in any one of claims 1-3, characterized in that, Specific methods include: (1) Select industrial pure aluminum ingots, Si source, Fe source, Mg source, rare earth source, Mn source, Ni source, Cu source, Zr source, Nb source and B source as raw materials and mix them according to the design composition; (2) Heat and melt industrial pure aluminum ingots at 710℃-750℃, add raw materials other than industrial pure aluminum ingots, and stir thoroughly after melting to make the composition of aluminum alloy liquid uniform. (3) The aluminum alloy liquid is refined in the furnace to remove gas and impurities. At a high temperature of 730℃-740℃, a large argon flow rate of 33-38L / min is used for stirring. At a low temperature of 705℃-715℃, a small argon flow rate of 18-21L / min is used for stirring to facilitate deep hydrogen removal. Then, it is allowed to stand for 35-55 minutes to remove slag. (4) Continuous casting and rolling, with a rolling temperature of 560℃-570℃, continuously casting and rolling into aluminum alloy round rods of 9-10mm; (5) The aluminum alloy round rod is subjected to solution treatment and aging treatment; (6) The aluminum alloy round rod is drawn into aluminum alloy wire and annealed to obtain rare earth modified high strength torsion resistant aluminum alloy cable with a wire diameter of 0.9-1.5mm.

5. The method for preparing rare earth-modified high-strength torsion-resistant aluminum alloy cable according to claim 4, characterized in that, In step (3), before continuous casting and rolling, ultrasonic treatment is performed with an ultrasonic power of 10-13 kW and a frequency of 2-3 kHz.

6. The method for preparing rare earth-modified high-strength torsion-resistant aluminum alloy cable according to claim 4, characterized in that, In step (5), the aluminum alloy round rod is solution-treated at 540℃-560℃ for 40-55h, and then aged at 310℃-330℃ for 67-77h.

7. The method for preparing rare earth modified high-strength torsion-resistant aluminum alloy cable according to claim 4, characterized in that, In step (6), annealing is performed at 170℃-190℃.