Composite microalloyed Al-Mg-Si-based aluminum alloy conductor and preparation method thereof

Abstract

The invention discloses a composite microalloyed Al-Mg-Si-based aluminum alloy conductor and a preparation method thereof, and relates to the technical field of nonferrous metal materials and processing thereof. The aluminum alloy conductor comprises the following raw material components in percentage by mass: 0.45%-0.55% of Mg, 0.40%-0.50% of Si, 0.12%-0.23% of Ce, 0.12%-0.23% of Sc, 0.05%-0.15% of Fe and the balance of Al. The preparation process comprises the steps of raw material mixing and melting, refining, casting, homogenization treatment, water cooling, hot rolling, drawing and aging treatment. By adding Mg, Si, Fe, Ce and Sc and combining a specific preparation process, the problem that high conductivity and high strength are difficult to balance in the prior art is solved, and it is detected that the conductivity of the prepared aluminum alloy conductor is larger than or equal to 61%, the tensile strength is larger than or equal to 145.0 Mpa, and the aluminum alloy conductor has high conductivity and high strength and has good application prospects in cables.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of non-ferrous materials and its processing technology, in particular to a composite micro-alloyed Al-Mg-Si-based aluminum alloy conductor and a preparation method thereof. BACKGROUND

[0002] Aluminum alloy conductor plays an irreplaceable core role in modern power transmission and distribution system. In the field of long-distance and large-capacity power transmission, aluminum alloy conductor is one of the best choices to balance technology and economy. Compared with pure aluminum, aluminum alloy conductor has more excellent mechanical properties, can bear more mechanical load, reduce the number of tower poles, and reduce the overall cost of the line. Compared with pure copper, aluminum alloy conductor has lower cost and lighter weight while ensuring sufficient electrical conductivity, achieving excellent cost performance. At the same time, aluminum alloy conductor is also a key material to promote green low-carbon and sustainable development. Its excellent electrical conductivity directly reduces the power loss in the transmission process of the line, improves energy utilization efficiency, and meets the global trend of energy saving and emission reduction.

[0003] Although industrial pure aluminum has excellent electrical conductivity, its strength is too low and its creep resistance is poor. In long-term mechanical load and high-temperature environment, pure aluminum wire is prone to plastic deformation and relaxation, which leads to an increase in sag and threatens the safety of the power grid, and cannot meet the demand of large-capacity and large-span power transmission. Conventional Al-Mg-Si series alloys can improve the strength through the aging precipitation of Mg2Si phase. However, in order to ensure that the electrical conductivity does not decrease too much, the addition amount of Mg and Si elements is limited, resulting in low strength improvement. The main means to improve the strength will introduce crystal defects and lattice distortion. These defects will have a strong scattering effect on the free electrons moving in a straight line, increase the resistance, and thus lead to a decrease in electrical conductivity. Therefore, in traditional material design, the pursuit of high strength often comes at the expense of electrical conductivity.

[0004] Chinese patent CN104532067A discloses a non-heat-treated medium-strength aluminum alloy conductor material and a preparation method thereof. The mass percentage of various elements is as follows: Fe: 0.35%~0.50%, Cu: 0.10%~0.25%, Mg: 0.01%~0.04%, B: 0.001%~0.002%, rare earth 0.02%~0.04%, and impurity elements Si≤0.11%, (Cr+Mn+V+Ti)≤0.015%, and the balance is Al. The obtained wire has an electrical conductivity of 59.6%IACS, a tensile strength of 269Mpa, and an elongation of 3.0%.

[0005] Chinese patent CN112111676 discloses a high-performance rare-earth aluminum alloy conductor and its preparation method. The composition of the aluminum alloy conductor is: Fe: 0.60~1.10wt%, Cu: 0.05~0.30wt%, B: 0.001~0.03wt%, Be: 0.001~0.20wt%, rare earth: 0.10~0.60wt%, Si≤0.08wt%, Mg≤0.01wt%, Zn≤0.02wt%, impurity content≤0.10wt%, and the remainder is Al. The rare earth elements include Ce, La, and Y. The obtained aluminum alloy conductor has a tensile strength of 103 MPa and a resistivity of no more than 27.900 nΩ•m at 20℃.

[0006] It is evident that there is an inverse relationship between electrical conductivity and strength; an increase in strength often implies a decrease in conductivity. This makes it difficult for existing aluminum alloy conductor manufacturing technologies to balance these two aspects. Therefore, developing aluminum alloy conductors that possess both high conductivity and high tensile strength has significant economic and social benefits. However, most current aluminum alloy conductors focus only on high strength or high conductivity (as shown in the patent above), lacking aluminum alloy conductors that simultaneously possess both high conductivity and high tensile strength. Summary of the Invention

[0007] To address the above shortcomings, this invention provides a composite microalloyed Al-Mg-Si based aluminum alloy conductor and its preparation method, which exhibits both good tensile strength and high conductivity. The specific technical solution is as follows: A composite microalloyed Al-Mg-Si based aluminum alloy conductor, wherein the raw material composition of the aluminum alloy conductor, by mass percentage, includes: Mg: 0.45%-0.55%, Si: 0.40%-0.50%, Ce: 0.12%-0.23%, Sc: 0.12%-0.23%, Fe: 0.05%-0.15%, with the remainder being Al.

[0008] Preferably, the aluminum alloy conductor raw material composition, by mass percentage, includes: Mg: 0.50%-0.55%, Si: 0.40%-0.45%, Ce: 0.15%-0.20%, Sc: 0.15%-0.20%, Fe: 0.10%-0.15%, with the remainder being Al.

[0009] This invention also provides a method for preparing a composite microalloyed Al-Mg-Si based aluminum alloy conductor, comprising the following steps: S1: Pure Al, Al-Mg master alloy, Al-Si master alloy, Al-Ce master alloy, Al-Sc master alloy and Al-Fe master alloy are sequentially mixed, melted, refined and cast to obtain as-cast aluminum alloy. S2: The cast aluminum alloy is subjected to homogenization treatment, water cooling, hot rolling and drawing in sequence to obtain an aluminum alloy conductor; S3: The aluminum alloy conductor is subjected to aging treatment to obtain the Al-Mg-Si based aluminum alloy conductor.

[0010] Preferably, in step S1, the melting is achieved by melting the pure Al sample at a temperature of 730-750°C.

[0011] Preferably, in step S1, the casting involves pouring the refined molten aluminum into a preheated mold for air-cooled casting, wherein the preheating temperature is 200℃-220℃.

[0012] Preferably, in step S2, the heat preservation temperature for homogenization treatment is 500℃-560℃, and the heat preservation time is 10-12h.

[0013] Preferably, in step S2, the hot rolling temperature is 350-450°C; the drawing temperature is room temperature, and the drawing passes are 7-9.

[0014] Preferably, in step S3, the holding temperature during the aging treatment is 175-225℃, and the holding time is 10-12h.

[0015] The composite microalloyed Al-Mg-Si based aluminum alloy conductor material provided by this invention can be used in cables.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention relates to a composite microalloyed Al-Mg-Si based aluminum alloy conductor. By improving the raw material composition, specifically by adding Mg, Si, Fe, Ce, and Sc, and combining this with a specific preparation process, a balance between high conductivity and high strength is achieved. Specifically, the Al3Sc nanoparticles formed by Sc and the Al-Si-Ce intermetallic compound formed by Ce create a highly dispersed and thermally stable second-phase particle group within the aluminum matrix. These particles enhance strength through precipitation strengthening and grain refinement strengthening effects. The formation of the precipitated phase increases the strength of the aluminum alloy. The distortion of the matrix lattice by the precipitated phase itself is much smaller than that caused by supersaturated solute atoms, and it effectively fixes the Mg and Si solute atoms, which have extremely strong electron scattering properties. This restores the lattice integrity of the aluminum matrix to near that of high-purity aluminum, creating favorable conditions for the free flow of electrons, thereby improving conductivity and tensile strength.

[0017] 2. This invention also constructs a multi-level, synergistic reinforcement system (see...). Figure 3The alloy is based on classic Mg2Si precipitation strengthening, with the performance improvement attributed to the synergistic effect of Ce and Sc, two microalloying elements. Mg and Si, as the main strengthening elements, are controlled in content and ratio to form strengthening phases. These precipitated phases effectively pin dislocations, producing a significant precipitation strengthening effect and improving yield strength and tensile strength. This compositional design also avoids the formation of coarse free Si phases or excess Mg solid solution, thus minimizing the adverse effects on conductivity and laying the foundation for high conductivity. The combined effect of the elements causes most alloying elements to precipitate from the aluminum matrix, forming strengthening phases and minimizing the scattering of electrons by solid solution atoms. This successfully overcomes the bottleneck of the mutual constraint between strength and conductivity in traditional aluminum alloys, achieving a comprehensive performance improvement.

[0018] 3. The composite microalloyed Al-Mg-Si based aluminum alloy conductor prepared by this invention has a conductivity of ≥61% at room temperature (20℃) and a room temperature ultimate tensile strength of ≥145.0 MPa, possessing both high conductivity and high strength. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0020] Figure 1 This is a process flow diagram for preparing the aluminum alloy conductor of the present invention; Figure 2 Here is a SEM image of the aged state of the aluminum alloy conductor in Example 3; Figure 3 This is a schematic diagram of the aluminum alloy conductor strengthening mechanism described in this invention. Detailed Implementation

[0021] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0022] Example 1 This embodiment provides a composite microalloyed Al-Mg-Si based aluminum alloy conductor and its preparation method: It comprises the following components by mass percentage: 0.50% Mg, 0.45% Si, 0.12% Ce, 0.12% Sc, 0.10% Fe, with the balance being Al.

[0023] S1: Sample weighing. Weigh pure Al, Al-Mg, Al-Si, Al-Ce, Al-Sc, and Al-Fe master alloys in sequence according to their mass percentages, and weigh 0.8% of the total alloy mass as refining agent. S2: Melting. Place the weighed pure Al sample in a heating furnace and keep it at 750℃ until all the pure Al is melted. Then, add Al-Mg, Al-Si, Al-Ce, Al-Sc, and Al-Fe master alloys in sequence, mix and melt thoroughly to obtain a melt. S3: Refining. Add the refining agent weighed in step S1 to the melt in step S2 and stir for 3 minutes. Keep it at a certain temperature for 5 minutes. After mixing thoroughly, remove the slag. Argon gas is introduced during the slag removal process. After the slag removal is completed, keep it at a certain temperature to obtain aluminum liquid. S4: Casting. Pour the molten aluminum from step S3 into a preheated mold (12mm in diameter) at 200℃ for hollow cold casting to obtain the cast aluminum alloy. S5: Homogenization treatment. The cast aluminum alloy from step S4 is placed in a heat treatment furnace, held at 560°C for 12 hours, and then the sample is removed and cooled with water to obtain a homogenized aluminum alloy sample. S6: Rolling and drawing process. The aluminum alloy sample after homogenization in step S5 is hot rolled at a rolling temperature of 400℃. After rolling, it is drawn in 8 passes at a drawing temperature of room temperature (20℃) to obtain an aluminum alloy conductor with a diameter of 3mm. S7: Aging treatment. The aluminum alloy conductor after rolling and drawing in step S6 is placed in a heat treatment furnace and held at 175°C for 12 hours. After the holding time is completed, the Al-Mg-Si based aluminum alloy conductor is obtained.

[0024] Example 2 This embodiment provides a composite microalloyed Al-Mg-Si based aluminum alloy conductor and its preparation method: It comprises the following components by mass percentage: 0.50% Mg, 0.45% Si, 0.15% Ce, 0.15% Sc, 0.10% Fe, with the balance being Al.

[0025] S1: Sample weighing. Weigh pure Al, Al-Mg, Al-Si, Al-Ce, Al-Sc, and Al-Fe master alloys in sequence according to their mass percentages, and weigh 0.8% of the total alloy mass as refining agent. S2: Melting. Place the weighed pure Al sample in a heating furnace and keep it at 750℃ until all the pure Al is melted. Then, add Al-Mg, Al-Si, Al-Ce, Al-Sc, and Al-Fe master alloys in sequence, mix and melt thoroughly to obtain a melt. S3: Refining. Add the refining agent weighed in step S1 to the melt in step S2 and stir for 3 minutes. Keep it at a certain temperature for 5 minutes. After mixing thoroughly, remove the slag. Argon gas is introduced during the slag removal process. After the slag removal is completed, keep it at a certain temperature to obtain aluminum liquid. S4: Casting. Pour the molten aluminum from step S3 into a preheated mold (12mm in diameter) at 200℃ for hollow cold casting to obtain the cast aluminum alloy. S5: Homogenization treatment. The cast aluminum alloy from step S4 is placed in a heat treatment furnace, held at 560°C for 12 hours, and then the sample is removed and cooled with water to obtain a homogenized aluminum alloy sample. S6: Rolling and drawing process. The aluminum alloy sample after homogenization in step S5 is hot rolled at a rolling temperature of 400℃. After rolling, it is drawn in 8 passes at a drawing temperature of room temperature (20℃) to obtain an aluminum alloy conductor with a diameter of 3mm. S7: Aging treatment. The aluminum alloy conductor after rolling and drawing in step S6 is placed in a heat treatment furnace and held at 175°C for 12 hours. After the holding time is completed, the Al-Mg-Si based aluminum alloy conductor is obtained.

[0026] Example 3 This embodiment provides a composite microalloyed Al-Mg-Si based aluminum alloy conductor and its preparation method: It comprises the following components by mass percentage: 0.50% Mg, 0.45% Si, 0.20% Ce, 0.20% Sc, 0.10% Fe, with the balance being Al.

[0027] S1: Sample weighing. Weigh pure Al, Al-Mg, Al-Si, Al-Ce, Al-Sc, and Al-Fe master alloys in sequence according to their mass percentages, and weigh 0.8% of the total alloy mass as refining agent. S2: Melting. Place the weighed pure Al sample in a heating furnace and keep it at 750℃ until all the pure Al is melted. Then, add Al-Mg, Al-Si, Al-Ce, Al-Sc, and Al-Fe master alloys in sequence, mix and melt thoroughly to obtain a melt. S3: Refining. Add the refining agent weighed in step S1 to the melt in step S2 and stir for 3 minutes. Keep it at a certain temperature for 5 minutes. After mixing thoroughly, remove the slag. Argon gas is introduced during the slag removal process. After the slag removal is completed, keep it at a certain temperature to obtain aluminum liquid. S4: Casting. Pour the molten aluminum from step S3 into a preheated mold (12mm in diameter) at 200℃ for hollow cold casting to obtain the cast aluminum alloy. S5: Homogenization treatment. The cast aluminum alloy from step S4 is placed in a heat treatment furnace, held at 560°C for 12 hours, and then the sample is removed and cooled with water to obtain a homogenized aluminum alloy sample. S6: Rolling and drawing process. The aluminum alloy sample after homogenization in step S5 is hot rolled at a rolling temperature of 400℃. After rolling, it is drawn in 8 passes at a drawing temperature of room temperature (20℃) to obtain an aluminum alloy conductor with a diameter of 3mm. S7: Aging treatment. The aluminum alloy conductor after rolling and drawing in step S6 is placed in a heat treatment furnace and held at 175°C for 12 hours. After the holding time is completed, the Al-Mg-Si based aluminum alloy conductor is obtained.

[0028] Example 4 This embodiment provides a composite microalloyed Al-Mg-Si based aluminum alloy conductor and its preparation method: It comprises the following components by mass percentage: 0.50% Mg, 0.45% Si, 0.23% Ce, 0.23% Sc, 0.10% Fe, with the balance being Al.

[0029] S1: Sample weighing. Weigh pure Al, Al-Mg, Al-Si, Al-Ce, Al-Sc, and Al-Fe master alloys in sequence according to their mass percentages, and weigh 0.8% of the total alloy mass as refining agent. S2: Melting. Place the weighed pure Al sample in a heating furnace and keep it at 750℃ until all the pure Al is melted. Then, add Al-Mg, Al-Si, Al-Ce, Al-Sc, and Al-Fe master alloys in sequence, mix and melt thoroughly to obtain a melt. S3: Refining. Add the refining agent weighed in step S1 to the melt in step S2 and stir for 3 minutes. Keep it at a certain temperature for 5 minutes. After mixing thoroughly, remove the slag. Argon gas is introduced during the slag removal process. After the slag removal is completed, keep it at a certain temperature to obtain aluminum liquid. S4: Casting. Pour the molten aluminum from step S3 into a preheated mold (12mm in diameter) at 200℃ for hollow cold casting to obtain the cast aluminum alloy. S5: Homogenization treatment. The cast aluminum alloy from step S4 is placed in a heat treatment furnace, held at 560°C for 12 hours, and then the sample is removed and cooled with water to obtain a homogenized aluminum alloy sample. S6: Rolling and drawing process. The aluminum alloy sample after homogenization in step S5 is hot rolled at a rolling temperature of 400℃. After rolling, it is drawn in 8 passes at a drawing temperature of room temperature (20℃) to obtain an aluminum alloy conductor with a diameter of 3mm. S7: Aging treatment. The aluminum alloy conductor after rolling and drawing in step S6 is placed in a heat treatment furnace and held at 175°C for 12 hours. After the holding time is completed, the Al-Mg-Si based aluminum alloy conductor is obtained.

[0030] Example 5 The composition of this embodiment is the same as that of Example 3 (by mass percentage, it includes the following components: 0.50% Mg, 0.45% Si, 0.20% Ce, 0.20% Sc, 0.10% Fe, with the balance being Al). The preparation method is the same as that of Example 3, except that the homogenization treatment temperature is 500℃.

[0031] Example 6 The components of this embodiment are the same as those of Example 3 (by mass percentage, including the following components: 0.50% Mg, 0.45% Si, 0.20% Ce, 0.20% Sc, 0.10% Fe, with the balance being Al). The preparation method is the same as that of Example 3, except that the aging treatment temperature is 225℃.

[0032] Example 7 The components of this embodiment are the same as those in Example 3 (by mass percentage, including the following components: 0.50% Mg, 0.45% Si, 0.20% Ce, 0.20% Sc, 0.10% Fe, with the balance being Al), and the preparation method is as follows: S1: Sample weighing. Weigh pure Al, Al-Mg, Al-Si, Al-Ce, Al-Sc, and Al-Fe master alloys in sequence according to their mass percentages, and weigh 1% of the total mass of the alloys as refining agent. S2: Melting. Place the weighed pure Al sample in a heating furnace and keep it at 730℃ until all the pure Al is melted. Then, add Al-Mg, Al-Si, Al-Ce, Al-Sc, and Al-Fe master alloys in sequence, mix and melt thoroughly to obtain a melt. S3: Refining. Add the refining agent weighed in step S1 to the melt in step S2 and stir for 3 minutes. Keep it at a certain temperature for 5 minutes. After mixing thoroughly, remove the slag. Argon gas is introduced during the slag removal process. After the slag removal is completed, keep it at a certain temperature to obtain aluminum liquid. S4: Casting. Pour the molten aluminum from step S3 into a preheated mold (12mm in diameter) at 220℃ for hollow cold casting to obtain the cast aluminum alloy. S5: Homogenization treatment. The cast aluminum alloy from step S4 is placed in a heat treatment furnace and held at 560°C for 10 hours. The sample is then removed and cooled with water to obtain a homogenized aluminum alloy sample. S6: Rolling and drawing process. The aluminum alloy sample after homogenization in step S5 is hot rolled at a rolling temperature of 350℃. After rolling, it is drawn in 9 passes at a drawing temperature of room temperature (20℃) to obtain an aluminum alloy conductor with a diameter of 3mm. S7: Aging treatment. The aluminum alloy conductor after rolling and drawing in step S6 is placed in a heat treatment furnace and held at 175°C for 10 hours. After the holding time is completed, the Al-Mg-Si based aluminum alloy conductor is obtained.

[0033] Example 8 The components of this embodiment are the same as those in Example 3 (by mass percentage, including the following components: 0.50% Mg, 0.45% Si, 0.20% Ce, 0.20% Sc, 0.10% Fe, with the balance being Al), and the preparation method is as follows: S1: Sample weighing. Weigh pure Al, Al-Mg, Al-Si, Al-Ce, Al-Sc, and Al-Fe master alloys in sequence according to their mass percentages, and weigh 1% of the total mass of the alloys as refining agent. S2: Melting. Place the weighed pure Al sample in a heating furnace and keep it at 730℃ until all the pure Al is melted. Then, add Al-Mg, Al-Si, Al-Ce, Al-Sc, and Al-Fe master alloys in sequence, mix and melt thoroughly to obtain a melt. S3: Refining. Add the refining agent weighed in step S1 to the melt in step S2 and stir for 3 minutes. Keep it at a certain temperature for 5 minutes. After mixing thoroughly, remove the slag. Argon gas is introduced during the slag removal process. After the slag removal is completed, keep it at a certain temperature to obtain aluminum liquid. S4: Casting. Pour the molten aluminum from step S3 into a preheated mold (12mm in diameter) at 220℃ for hollow cold casting to obtain the cast aluminum alloy. S5: Homogenization treatment. The cast aluminum alloy from step S4 is placed in a heat treatment furnace and held at 560°C for 10 hours. The sample is then removed and cooled with water to obtain a homogenized aluminum alloy sample. S6: Rolling and drawing process. The aluminum alloy sample after homogenization in step S5 is hot rolled at a rolling temperature of 450℃. After rolling, it is drawn in 7 passes at a drawing temperature of room temperature (20℃) to obtain an aluminum alloy conductor with a diameter of 3mm. S7: Aging treatment. The aluminum alloy conductor after rolling and drawing in step S6 is placed in a heat treatment furnace and held at 175°C for 10 hours. After the holding time is completed, the Al-Mg-Si based aluminum alloy conductor is obtained.

[0034] Comparative Example 1 This comparative example has the same composition as Example 3 (by mass percentage, it includes the following components: 0.50% Mg, 0.45% Si, 0.20% Ce, 0.20% Sc, 0.10% Fe, with the balance being Al). The preparation process is the same as Example 3, except that hot rolling is replaced with cold rolling.

[0035] Comparative Example 2 This comparative example differs from Example 3 in that it comprises, by mass percentage, the following components: 0.50% Mg, 0.45% Si, 0.10% Fe, with the balance being Al. The preparation method is the same as in Example 3.

[0036] Comparative Example 3 This comparative example differs from Example 3 in that it comprises, by mass percentage, the following components: 0.50% Mg, 0.45% Si, 0.20% Ce, 0.10% Fe, with the balance being Al. The preparation method is the same as in Example 3.

[0037] Comparative Example 4 This comparative example differs from Example 3 in that it comprises, by mass percentage, the following components: 0.50% Mg, 0.45% Si, 0.20% Sc, 0.10% Fe, with the balance being Al. The preparation method is the same as in Example 3.

[0038] Comparative Example 5 This comparative example differs from Example 3 in that it comprises, by mass percentage, the following components: 0.50% Mg, 0.45% Si, 0.10% Ce, 0.10% Sc, 0.10% Fe, with the balance being Al. The preparation method is the same as in Example 3.

[0039] Comparative Example 6 This comparative example differs from Example 3 in that it comprises, by mass percentage: 0.50% Mg, 0.45% Si, 0.25% Ce, 0.25% Sc, 0.10% Fe, with the balance being Al. The preparation method is the same as in Example 3.

[0040] The mechanical properties and electrical conductivity of each embodiment and comparative example were tested, and the results are shown in Table 1: Table 1 Performance test data at room temperature (20℃) Analysis of the data in the table above: Data from Examples 1 to 4 show that, with identical processing and heat treatment processes, the alloy composition significantly impacts the performance of the aluminum alloy conductor. Ce and Sc can form fine Al3Sc and Al-Si-Ce precipitates in the Al-Mg-Si alloy. These precipitates refine the grains, inhibit recrystallization, and increase the recrystallization temperature, thus playing a role in precipitation strengthening and grain refinement. As the Ce and Sc content increases from 0.12% to 0.23%, the number of precipitates increases, enhancing the strengthening effect. Consequently, the tensile strength continuously improves, reaching over 145 MPa. The addition of Ce and Sc reduces the solid solubility of Mg and Si in the aluminum matrix, promotes precipitate formation, and reduces electron scattering, thereby improving electrical conductivity, which can reach over 61% IACS. In particular, Example 3 maintains a high conductivity of 61.4% IACS even at a high tensile strength of 155 MPa. Compared to ordinary high-strength aluminum alloys, it has an absolute advantage in conductivity at similar strengths, resulting in higher transmission capacity.

[0041] Data from Example 3 and Comparative Example 1 show that, with the same composition, changing the processing technology to cold rolling, when performed at room temperature, leads to work hardening, introduces high-density dislocations and internal stress, and therefore the electrical conductivity is lower than that of hot rolling.

[0042] Data from Examples 3 and Comparative Examples 2, 3, and 4 show that the tensile strength of Comparative Example 2 (without Ce or Sc) is only 96 MPa; the tensile strengths of Comparative Example 3 (with only Ce) and Comparative Example 4 (with only Sc) are only around 135 MPa, both below 145 MPa. This indicates that the individual addition of Ce or Sc has limited effect on strengthening the mechanical properties of aluminum alloy conductors, and the conductivity is also insufficient. Therefore, Sc and Ce in this invention have a synergistic effect, and their combined use can achieve a joint improvement in strength and conductivity.

[0043] Data from Examples 3 and Comparative Examples 5 and 6 show that excessive addition of Ce and Sc (Comparative Example 6) leads to coarsening of the precipitates or the formation of brittle phases, thereby reducing toughness. Simultaneously, excessive precipitates increase electron scattering and reduce electrical conductivity (only 60.5% IACS). Conversely, insufficient addition of Ce and Sc (Comparative Example 5) results in a reduced number of precipitates and insufficient strength (tensile strength only 137 MPa). Therefore, both excessive and insufficient addition of Ce and Sc can easily lead to a decrease in the overall performance of the aluminum alloy conductor.

[0044] In summary, the preparation method of the composite microalloyed Al-Mg-Si based aluminum alloy conductor described in this invention achieves both high mechanical strength and high electrical conductivity. This composite microalloyed Al-Mg-Si based aluminum alloy conductor offers comprehensive advantages in wire and cable applications, primarily due to the synergistic effect of Ce and Sc elements. Compared to pure aluminum, it maintains nearly the same high conductivity while significantly improving tensile strength. This allows for effective reduction of sag caused by self-weight and external loads when used as an overhead transmission conductor, enabling larger tower spans and thus significantly reducing the construction and support structure costs of the line. Compared to ordinary high-strength aluminum alloys, it has an absolute advantage in electrical conductivity while achieving similar strength, resulting in higher transmission capacity. Furthermore, the material's good plasticity ensures reliable processing and installation, and its refined microstructure provides superior creep resistance and corrosion resistance, extending the cable's service life in harsh environments. This method has a simple preparation process, is easy to industrialize, and represents a promising aluminum alloy conductor for various applications.

[0045] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A composite microalloyed Al-Mg-Si based aluminium alloy conductor, characterized in that, The raw material components of the aluminum alloy conductor include, in terms of mass percentage: Mg: 0.45%-0.55%, Si: 0.40%-0.50%, Ce: 0.12%-0.23%, Sc: 0.12%-0.23%, Fe: 0.05%-0.15%, and the rest is Al.

2. A composite microalloyed Al-Mg-Si based aluminium alloy conductor according to claim 1, characterized in that, The raw material components of the aluminum alloy conductor include, in terms of mass percentage: Mg: 0.50%-0.55%, Si: 0.40%-0.45%, Ce: 0.15%-0.20%, Sc: 0.15%-0.20%, Fe: 0.10%-0.15%, and the rest is Al.

3. A method of producing a composite microalloyed Al-Mg-Si based aluminium alloy conductor as claimed in claim 1 or 2, characterised in that, The method comprises the following steps: S1: sequentially mixing and melting, refining, and casting pure Al, Al-Mg intermediate alloy, Al-Si intermediate alloy, Al-Ce intermediate alloy, Al-Sc intermediate alloy, and Al-Fe intermediate alloy to obtain a cast aluminum alloy; S2: sequentially subjecting the cast aluminum alloy to homogenization treatment, water cooling, hot rolling, and drawing to obtain an aluminum alloy conductor; S3: subjecting the aluminum alloy conductor to aging treatment to obtain the Al-Mg-Si-based aluminum alloy conductor.

4. A method of producing a composite microalloyed Al-Mg-Si based aluminium alloy conductor according to claim 3, characterized in that, In step S1, the melting is performed by heating and melting the pure Al sample at 730-750°C.

5. The method for preparing a composite microalloyed Al-Mg-Si based aluminum alloy conductor according to claim 3, characterized in that, In step S1, the casting is performed by pouring the refined aluminum liquid into a preheated mold for air cooling casting, and the preheating temperature is 200-220°C.

6. The method for preparing a composite microalloyed Al-Mg-Si based aluminum alloy conductor according to claim 3, characterized in that, In step S2, the homogenization treatment is performed at a holding temperature of 500-560°C for 10-12h.

7. The method for preparing a composite microalloyed Al-Mg-Si based aluminum alloy conductor according to claim 3, characterized in that, In step S2, the hot rolling is performed at a rolling temperature of 350-450°C, and the drawing is performed at room temperature with 7-9 drawing passes.

8. The method for preparing a composite microalloyed Al-Mg-Si based aluminum alloy conductor according to claim 3, characterized in that, In step S3, the aging treatment is performed at a holding temperature of 175-225°C for 10-12h.

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