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

Abstract

The application discloses a high-strength high-conductivity high-thermal-conductivity aluminum alloy material and a preparation method thereof. The aluminum alloy comprises the following components in percentage by mass: Mg: 0.50-0.90 wt.%, Si: 0.40-0.65 wt.%, Zr: 0.05-0.20 wt.%, Ce: 0.10-0.30 wt.%, Sr: 0.0005-0.01 wt.%, and the balance of aluminum and inevitable impurity elements; and the preparation method comprises the following steps: aluminum melt boronization, converter, alloying, degassing refining, component adjustment, casting, hot deformation, online solid solution, pre-aging, low-temperature aging, cold deformation and artificial aging. The aluminum alloy material prepared by the application has a tensile strength of greater than or equal to 350 MPa, an elongation of greater than or equal to 5.8%, an electrical conductivity of greater than or equal to 55% IACS, and a thermal conductivity of greater than or equal to 190 W / (m*K) at a service temperature of 90 DEG C. The material prepared by the application can be used as an electrically-conductive, thermally-conductive and structural material, including but not limited to a wire, a bus, a current-carrying wire, a power fitting or other components with heat dissipation requirements, and is particularly suitable for preparing large-span large-capacity overhead transmission lines.

Description

Technical Field

[0001] This invention relates to a high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material and its preparation method, belonging to the field of metallurgical materials technology. Technical Background

[0002] With the rapid development of my country's economy and society, electricity demand has increased year by year, placing higher demands on the construction of the power grid. To address the contradiction between power supply and demand, alleviate the pressure on power transmission, and optimize resource allocation, transmission lines are gradually developing towards longer distances and larger capacities. As the main carrier of power transmission, the performance of overhead transmission conductors directly affects the reliability and stability of the power system. When overhead transmission conductors are used for power transmission, their operating temperature rises due to the Joule heating effect generated by current carrying. Simultaneously, the higher temperature increases the conductor resistance, promoting Joule heating and further raising the operating temperature until a dynamic equilibrium is reached. To reduce the increase in conductor resistance caused by line temperature rise, reduce energy loss, and increase conductor current carrying capacity, it is urgent to develop aluminum alloy materials that combine high strength, high electrical conductivity, and high thermal conductivity.

[0003] Currently, patents related to aluminum alloy conductor materials mainly focus on the material's strength and electrical conductivity, with less attention paid to thermal conductivity, especially high-temperature thermal conductivity. For example, patent CN111270112A discloses a high-strength, high-conductivity aluminum alloy for overhead conductors and its preparation method. The overhead conductor has a strength of 315 MPa and a conductivity of 56.5% IACS. This conductor exhibits good conductivity and strength matching, but does not address the material's thermal conductivity. Patent CN108588515A discloses a high-strength, high-conductivity aluminum alloy conductor and its preparation method. The prepared conductor has a single filament strength of 330 MPa and a conductivity of 54% IACS. Again, the thermal conductivity of the alloy was not tested, and the conductivity is relatively low. Patent CN101121978A discloses a high-conductivity, high-thermal-conductivity, and high-strength aluminum alloy material, its preparation method, and its applications. The prepared aluminum alloy material has a room-temperature conductivity of 59.2% IACS and a theoretical thermal conductivity of 220 W / (m·K), but its strength is only 173 MPa, making it unsuitable for use as overhead conductors. Patent CN114395715A discloses a high-thermal-conductivity aluminum alloy and its preparation method, which uses Sr+Ca composite addition to modify the Si particles in the aluminum alloy, achieving a thermal conductivity of 190 W / (m·K). However, the aluminum alloy has low strength and is not suitable for plastic processing.

[0004] Compared with existing technical solutions, this invention, based on previous research (such as patent 2023102969678), has prepared an aluminum alloy material with high strength, high electrical conductivity and thermal conductivity by adjusting the composition and improving the production process. It is especially suitable for manufacturing high-strength overhead conductors. With simple process adjustments, the material designed in this invention can also be used to manufacture busbars, drain wires, power fittings or other components with heat dissipation requirements. Summary of the Invention

[0005] One objective of this invention is to overcome the shortcomings of existing technologies and provide a high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material, wherein the aluminum alloy comprises the following components by mass percentage:

[0006] Mg: 0.50–0.90 wt.%;

[0007] Si: 0.40–0.65 wt.%;

[0008] Zr: 0.05~0.20wt.%;

[0009] Ce: 0.10–0.30 wt.%;

[0010] Sr: 0.0005~0.01wt.%;

[0011] The balance consists of Al and unavoidable impurity elements.

[0012] Preferably, the high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material comprises, by weight percentage, the following components:

[0013] Mg: 0.55–0.80 wt.%;

[0014] Si: 0.50–0.60 wt.%;

[0015] Zr: 0.05~0.15wt.%;

[0016] Ce: 0.15–0.25 wt.%;

[0017] Sr: 0.001~0.005wt.%;

[0018] The balance consists of Al and unavoidable impurity elements; wherein, among the unavoidable impurity elements, the residual content of element B is less than 0.01 wt.%, the content of element Fe is less than 0.10 wt.%, and the total content of elements Ti, V, Cr, and Mn is less than 0.010 wt.%.

[0019] In this invention, Mg and Si are the main strengthening elements. Through a solution-aging process, Mg and Si elements are precipitated as strengthening phases, synergistically improving strength, electrical conductivity, and thermal conductivity. The Mg content is 0.50–0.90 wt.%, the Si content is 0.40–0.65 wt.%, and the Mg / Si ratio is 0.8–1.5, specifically, such as 0.8, 0.9, 1.0, 1.2, 1.3, 1.4, and 1.5. When the Mg and Si content exceeds the aforementioned composition range and / or ratio range, the optimal balance of strength, thermal conductivity, and electrical conductivity cannot be achieved.

[0020] In this invention, Zr can refine grains and form nanoscale Al3Zr particles during processing, thereby inhibiting dynamic recrystallization and improving the alloy's strength and thermal stability. The Zr content ranges from 0.05 to 0.20 wt.%, preferably from 0.05 to 0.15 wt.%, specifically, such as 0.05 wt.%, 0.07 wt.%, 0.09 wt.%, 0.11 wt.%, 0.13 wt.%, and 0.15 wt.%. When the Zr content is below 0.05 wt.%, Zr is difficult to form Al3Zr particles, resulting in insufficient thermal stability of the aluminum conductor material; when the Zr content is above 0.20 wt.%, excessive Zr will dissolve in the aluminum matrix, severely reducing the alloy's electrical and thermal conductivity.

[0021] In this invention, Ce can refine grains and alter the Fe-rich phase and Mg-Si intermediate phase in the alloy. The Ce content ranges from 0.10 to 0.30 wt.%, preferably 0.15 to 0.25 wt.%, specifically, such as 0.15 wt.%, 0.17 wt.%, 0.19 wt.%, 0.21 wt.%, 0.23 wt.%, and 0.25 wt.%. When the Ce content is below 0.1 wt.%, the beneficial effect of Ce is not significant. When the Ce content is above 0.30 wt.%, on the one hand, it increases the Ce content dissolved in the aluminum matrix, worsening the electrical and thermal conductivity of the alloy; on the other hand, Ce can combine with Si in the alloy to form high-temperature stable CeSi rare earth compounds, indirectly reducing the volume fraction of the Mg-Si strengthening phase, thereby reducing the alloy strength.

[0022] In this invention, an appropriate amount of Sr can improve the morphology of the Mg-Si mesophase and promote the transformation of acicular or plate-like β-AlFeSi into granular or spherical α-AlFeSi, reducing the alloy's tendency for hot cracking. Furthermore, an appropriate amount of Sr can promote the desolvation of Mg and Si atoms to form a strengthening phase, synergistically improving strength, electrical conductivity, and thermal conductivity. The Sr content ranges from 0.0005 to 0.01 wt.%, preferably from 0.001 to 0.005 wt.%, specifically, such as 0.001 wt.%, 0.0015 wt.%, 0.002 wt.%, 0.0025 wt.%, 0.003 wt.%, 0.0035 wt.%, 0.004 wt.%, 0.0045 wt.%, and 0.005 wt.%. When the Sr content is below 0.0005 wt.%, it cannot play a role in modifying the alloy or promoting the precipitation of strengthening phases; when the Sr content is above 0.005 wt.%, it will cause severe hydrogen absorption in the molten aluminum, resulting in casting defects such as shrinkage porosity and inclusions, and deteriorating the alloy's strength, electrical conductivity and thermal conductivity.

[0023] In this invention, industrial-grade remelted aluminum ingots or primary aluminum liquid are used as raw materials, with a purity of not less than 99.7 wt.%. The alloying elements such as Mg, Si, Zr, Ce, and Sr are added in the form of intermediate alloys.

[0024] Another objective of this invention is to provide a method for preparing a high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy conductor.

[0025] This invention discloses a method for preparing a high-strength, high-electrical-conductivity, and thermally-conductivity aluminum alloy material. The preparation method includes the following steps: aluminum melt boronizing, converter, smelting, casting, hot deformation, online solution treatment, pre-aging, low-temperature aging, cold deformation, and artificial aging.

[0026] This invention discloses a method for preparing a high-strength, high-electrical-conductivity, and thermally-conductivity aluminum alloy. The boronizing of the aluminum melt requires first heating the aluminum raw material to 780–850°C, then adding an Al-B master alloy for boronizing. The Ti and V content of the boronized aluminum melt is then tested. When both Ti and V contents are below 0.005 wt.%, the melt is transferred to a converter. If the Ti and V contents do not meet the standards, multiple boronizing processes are required until the standards are met. The converter operation can be used to remove diborides with a specific gravity greater than the aluminum melt generated after boronizing, resulting in purified aluminum melt.

[0027] This invention discloses a method for preparing a high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material. The smelting process includes alloying, degassing and refining, composition adjustment, and settling of the molten aluminum. Specifically, the temperature of the molten aluminum after the converter is controlled at 690–730°C. Then, Al-Si, Al-Zr, Al-Ce, Al-Sr, and Al-Mg master alloys are added sequentially. After the master alloys are completely melted, stirring and degassing refining are performed. Rapid composition analysis is conducted before the furnace, and composition adjustments are made according to the designed composition ratio. The molten aluminum is then allowed to settle. During degassing and refining, industrial-grade pure N2 is used to blow the refining agent into the molten aluminum, and the amount of refining agent added is controlled to be 0.2–0.5 wt.% of the melt mass. The refining time is not less than 15 minutes.

[0028] This invention discloses a method for preparing a high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material. The casting process is selected from at least one of ordinary casting, semi-continuous casting, continuous casting, and die casting. The casting temperature is 690–730℃. Casting can yield ordinary billets, continuously cast billets, castings, and die castings. The billets can be directly used as finished large-section busbars or as hot-deformation blanks; the castings or die castings can be used to process power fittings or heat dissipation components. The properties of the billets and / or castings and die castings can be improved through heat treatment.

[0029] This invention discloses a method for preparing a high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material. In the resulting cast product, the CeSi rare earth compound has three morphologies: needle-like, spherical, and short rod-like.

[0030] This invention discloses a method for preparing a high-strength, high-electrical-conductivity, and thermally-conductivity aluminum alloy material, wherein the hot deformation is selected from subsequent processing steps of the cast billet, including at least one of hot rolling, hot extrusion, and hot continuous rolling.

[0031] This invention discloses a method for preparing high-strength, high-electrical-conductivity, and thermally-conductivity aluminum alloy materials. The online solid solution refers to the process of dissolving low-melting-point phases back through the deformation heat generated by hot deformation, followed by rapid cooling to obtain a supersaturated solid solution, including but not limited to rapid cooling after hot rolling, rapid cooling after hot extrusion, and rapid cooling after continuous hot rolling.

[0032] This invention discloses a method for preparing a high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material. The hot rolling process is carried out after homogenization treatment of the cast billet. The homogenization temperature is 550–570℃, and the homogenization time is 6–16 hours. During hot rolling, the entry temperature is 510–530℃, the rolling deformation is not less than 80%, and the exit temperature is not less than 540℃. The prepared aluminum rod is directly quenched in a cooling medium selected from at least one of water and quenching oil, with a quenching cooling rate greater than 100℃ / s.

[0033] This invention discloses a method for preparing a high-strength, high-electrical-conductivity, and thermally-conductivity aluminum alloy material. The hot extrusion is performed after the billet has undergone homogenization treatment at a temperature of 550–570°C for 6–16 hours. During hot extrusion, the extrusion temperature is 510–530°C, and the extrusion deformation is not less than 80%. The extruded aluminum rod is directly quenched in a cooling medium selected from at least one of water and quenching oil, with a cooling rate greater than 100°C / s. Preferably, during hot extrusion, the speed at which the metal flows out of the die is controlled to be 5–15 m / min.

[0034] This invention discloses a method for preparing a high-strength, high-electrical-conductivity, and thermally-conductivity aluminum alloy material. The hot continuous rolling process involves controlling the continuous casting billet temperature to 520–550°C by adjusting the casting wheel speed and cooling water pressure. The mill emulsion temperature is controlled to 20–50°C, the mill cooling water pressure to 250–400 kPa, and the cooling water temperature to be below 30°C. The hot continuous rolling deformation is not less than 80%. The billet exit temperature is kept below 60°C by adjusting the emulsion temperature and cooling water temperature.

[0035] This invention involves hot deformation (such as hot extrusion) followed by direct quenching to obtain online solution-treated round aluminum rods. The prepared round aluminum rods do not undergo dynamic recrystallization, and the grain morphology exhibits an elongated fibrous structure.

[0036] This invention discloses a method for preparing a high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material. The pre-aging process involves heating to 170–200°C at a rate of 3–5 K / min, holding at that temperature for 10–60 min, preferably 15–45 min, and then cooling to room temperature. The pre-aging is performed rapidly after the billet has been quenched, with an interval not exceeding 1 hour. The purpose of the pre-aging is to increase the number of β” strengthening phase nuclei. In practical applications, a cooling rate of at least 50°C / s is used for rapid cooling to room temperature.

[0037] This invention discloses a method for preparing a high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material. The low-temperature aging temperature is 60–80°C, and the low-temperature aging time is 1–2 weeks. The low-temperature aging is carried out rapidly after pre-aging, and its purpose is to promote secondary desolvation in the GP zone, thereby promoting the precipitation of strengthening phases during subsequent artificial aging, and synergistically improving the strength, electrical conductivity, and thermal conductivity of the aluminum alloy.

[0038] This invention discloses a method for preparing a high-strength, high-electrical-conductivity, and thermally-conductivity aluminum alloy material. The cold deformation includes, but is not limited to, cold drawing. The pass rate of the drawing process is 10-35%, the drawing speed is 5-15 m / s, and a single wire with a diameter of 2.5-4.0 mm is obtained.

[0039] This invention discloses a method for preparing a high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material. The artificial aging process involves heating to 170-200°C at a rate of 3-5°C / min, holding at that temperature for 3-10 hours, preferably 3-6 hours, followed by air cooling. The purpose of this artificial aging is to promote the desolvation of Mg and Si atoms to form a strengthening phase, thereby synergistically improving the strength, electrical conductivity, thermal conductivity, and elongation of the aluminum conductor. An aging time exceeding 10 hours results in lower conductor strength, while an aging time less than 3 hours results in lower electrical conductivity, thermal conductivity, and elongation.

[0040] This invention discloses a method for preparing a high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material, wherein the aluminum alloy comprises the following components by mass percentage:

[0041] Mg: 0.80 wt.%; Si: 0.60 wt.%; Zr: 0.08 wt.%; Ce: 0.1 wt.%; Sr: 0.0012 wt.%; balance being Al and unavoidable impurity elements.

[0042] After online solution treatment, the aluminum rod is pre-aged at 175℃ for 20 minutes, then aging at 70℃ for one week, and then drawn. The drawing process has a pass rate of 10-35%, which decreases as the total deformation increases. The drawing speed is 10 m / s to obtain a single wire with a diameter of 3.5 mm. Finally, it is aged at 170℃ for 6 hours to obtain the finished wire. The finished wire has a single wire strength of 355 MPa, an elongation of 6.1%, a conductivity of 55.0% IACS, and a measured thermal conductivity of 190 W / (m·K) at 90℃.

[0043] After online solution treatment, the aluminum rod is pre-aged at 180℃ for 15 minutes, then aging at 70℃ for 1 week, and then drawn. The drawing process has a pass rate of 10-35%, which decreases as the total deformation increases. The drawing speed is 10 m / s to obtain a single wire with a diameter of 3.5 mm. Finally, it is aged at 170℃ for 6 hours to obtain the finished wire. The single wire strength of the finished wire is 353 MPa, the elongation is 5.8%, the conductivity is 55.2% IACS, and the measured thermal conductivity at 90℃ is 193 W / (m·K).

[0044] After online solution treatment, the aluminum rod is pre-aged at 175℃ for 20 minutes, then aging at 70℃ for one week, and then drawn. The drawing process has a pass rate of 10-35%, which decreases as the total deformation increases. The drawing speed is 10 m / s to obtain a single wire with a diameter of 3.5 mm. Finally, it is aged at 175℃ for 5 hours to obtain the finished wire. The single wire strength of the finished wire is 352 MPa, the elongation is 8.0%, the conductivity is 55.1% IACS, and the measured thermal conductivity at 90℃ is 188 W / (m·K).

[0045] After online solution treatment, the aluminum rod undergoes pre-aging at 175℃ for 20 minutes, followed by low-temperature aging at 70℃ for one week, and then drawing. The drawing pass rate is 10-35%, decreasing with increasing total deformation, at a speed of 10 m / s, yielding a 3.5 mm diameter monofilament. Finally, it undergoes aging at 180℃ for 3.5 hours to obtain the finished conductor. The resulting conductor has a monofilament strength of 350 MPa, an elongation of 10.2%, a conductivity of 55.3% IACS, and a measured thermal conductivity of 195 W / (m·K) at 90℃. This method produces a product with significantly better elongation than other products, and its mechanical, electrical, and thermal properties are also extremely superior, greatly exceeding expectations.

[0046] The beneficial effects of this invention are as follows:

[0047] (1) In the design of alloy composition, the reasonable ratio of Mg and Si content avoids the adverse effects of excessive Mg and / or Si on the electrical and thermal conductivity of aluminum conductor materials; an appropriate amount and trace amount of Zr can refine the grains, improve the hot working stability of the alloy, inhibit dynamic recrystallization, and enable the cold-deformed wire to maintain a considerable strain strengthening effect after artificial aging; the addition of Ce and Sr plays the role of refining the grains and modifying the harmful FeSi phase. In addition, an appropriate amount of Sr can also promote the desolvation of solid solution Mg and Si, and synergistically improve the strength, electrical conductivity and thermal conductivity.

[0048] (2) In terms of preparation process, online solid solution technology shortens the process flow and effectively promotes the solid solution of Mg and Si atoms in the aluminum matrix to provide driving force for subsequent aging process; pre-aging + low temperature aging process effectively promotes the formation of strengthening phase core and stable GP region, and artificial aging after cold deformation can form a higher density strengthening phase.

[0049] (3) The aluminum alloy material prepared by this invention has a tensile strength ≥350MPa, elongation ≥5.8%, conductivity ≥55%IACS, and measured thermal conductivity ≥190W / (m·K) at a service temperature of 90℃. The material designed and prepared by this invention can be used as a conductive, heat-dissipating, and structural material, including but not limited to conductors, busbars, lead wires, power fittings, or other components with heat dissipation requirements, and is particularly suitable for the preparation of long-span, high-capacity overhead transmission lines. Attached image description:

[0050] Figure 1 This is a metallographic photograph of the product after extrusion in Embodiment 1 of the present invention;

[0051] Figure 2 This is a metallographic photograph of the extruded material in Comparative Example 6 of this invention;

[0052] Figure 3 This is a scanned image of the as-cast state of Embodiment 1 of the present invention;

[0053] Figure 4 for Figure 1 The energy spectrum of point A;

[0054] Figure 5 This is a transmission electron microscope (TEM) image of a single wire of the conductor in Embodiment 6 of the present invention;

[0055] Figure 6 This is a transmission electron microscope (TEM) image of a single wire of the comparative example 11 of this invention.

[0056] Specific implementation:

[0057] The technical solution of the present invention will be further described below through specific embodiments, so that those skilled in the art can better understand the invention and implement it. However, the embodiments are not intended to limit the present invention.

[0058] Example 1

[0059] This embodiment provides a method for preparing a high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material. An online solution-treated aluminum rod is prepared using the following process. The tensile strength and conductivity of the online solution-treated aluminum rod are tested to demonstrate the beneficial effects of the aluminum alloy material composition of this invention. The specific steps are as follows:

[0060] Step 1: Prepare the raw materials according to the following mass percentages: Mg: 0.8 wt.%, Si: 0.6 wt.%, Zr: 0.08 wt.%, Ce: 0.1 wt.%, Sr: 0.0012 wt.%, with the balance being Al and unavoidable impurity elements; wherein, among the unavoidable impurity elements, the residual B element is less than 0.01 wt.%, the Fe element content is less than 0.10 wt.%, and the total content of Ti, V, Cr, and Mn is less than 0.010 wt.%.

[0061] Step 2: Melt 99.7 wt.% industrial pure aluminum at 750℃, then heat the aluminum liquid to 820℃, add Al-B master alloy for boronizing treatment, and test the Ti and V content of the boronized aluminum liquid. When the Ti and V content are both below 0.005 wt.%, proceed with the converter operation.

[0062] Step 3: Cool the aluminum liquid after the converter to 720℃, and add Al-Si, Al-Zr, Al-Ce, Al-Sr and Al-Mg master alloys in sequence. After the master alloys are completely melted, mechanically stir for 15 minutes. Use industrial pure N2 to blow the refining agent into the aluminum liquid for 15 minutes of refining. After the aluminum liquid is refined, let it stand and control the casting temperature at 720℃ for casting to obtain the alloy billet.

[0063] Step 4: The billet is subjected to homogenization heat treatment at 560℃ for 8 hours, then air-cooled to room temperature, and then machined into a metal billet suitable for extrusion.

[0064] Step 5: The metal billet is hot-extruded at 510℃, and the metal flows out of the die at a speed of 10m / min. The extruded aluminum rod is directly quenched in water to obtain an online solution-treated round aluminum rod.

[0065] Example 2

[0066] The other conditions are the same as in Example 1, except that the composition has been adjusted. The specific composition is shown in Table 1, and the properties of the resulting linear solution-treated round aluminum rod are shown in Table 2.

[0067] Example 3

[0068] The other conditions are the same as in Example 1, except that the composition has been adjusted. The specific composition is shown in Table 1, and the properties of the resulting linear solution-treated round aluminum rod are shown in Table 2.

[0069] Example 4

[0070] The other conditions are the same as in Example 1, except that the composition has been adjusted. The specific composition is shown in Table 1, and the properties of the resulting linear solution-treated round aluminum rod are shown in Table 2.

[0071] Example 5

[0072] The other conditions are the same as in Example 1, except that the composition has been adjusted. The specific composition is shown in Table 1, and the properties of the resulting linear solution-treated round aluminum rod are shown in Table 2.

[0073] Comparative Example 1

[0074] Other conditions were the same as in Example 1, except for adjustments to the composition, as detailed in Table 1. The properties of the resulting linear solution-treated round aluminum rod are shown in Table 2. The biggest difference between the linear solution-treated aluminum rod described in this comparative example and that of Example 1 is only the Mg / Si ratio.

[0075] Comparative Example 2

[0076] Other conditions were the same as in Example 1, except for adjustments to the composition, as shown in Table 1. The properties of the resulting solution-treated round aluminum rods are shown in Table 2. The biggest difference between this comparative example and Example 1 is the absence of Zr.

[0077] Comparative Example 3

[0078] Other conditions were the same as in Example 1, except for adjustments to the composition, as shown in Table 1. The properties of the resulting solution-treated round aluminum rods are shown in Table 2. The biggest difference between this comparative example and Example 1 was the excessively high Zr content.

[0079] Comparative Example 4

[0080] Other conditions were the same as in Example 1, except for adjustments to the composition, as detailed in Table 1. The properties of the resulting solution-treated round aluminum rods are shown in Table 2. The biggest difference between this comparative example and Example 1 was the absence of Ce element.

[0081] Comparative Example 5

[0082] Other conditions were the same as in Example 1, except for adjustments to the composition, as shown in Table 1. The properties of the resulting solution-treated round aluminum rods are shown in Table 2. The biggest difference between this comparative example and Example 1 was the excessively high Ce content.

[0083] Comparative Example 6

[0084] Other conditions were the same as in Example 1, except for adjustments to the composition, as shown in Table 1. The properties of the resulting solution-treated round aluminum rods are shown in Table 2. The biggest difference between this comparative example and Example 1 was the absence of Sr.

[0085] Comparative Example 7

[0086] Other conditions were the same as in Example 1, except for adjustments to the composition, as detailed in Table 1. The properties of the resulting solution-treated round aluminum rods are shown in Table 2. The biggest difference between this comparative example and Example 1 was the excessively high Sr content.

[0087] Table 1 shows the alloy element composition of Examples 1-5 and Comparative Examples 1-7, where the content of each element is a mass percentage.

[0088] Table 1 Alloy element composition

[0089]

[0090] The online solution-treated aluminum rods prepared according to the compositions of Examples 1-5 and Comparative Examples 1-7 were subjected to strength tests according to standard GB / T 228.1-2010, and the conductivity of the aluminum rods at 20℃ was tested according to GB / T 12966-2008. The results are shown in Table 2. The performance comparison between Comparative Example 1 and Example 1 shows that a suitable Mg / Si element ratio can obtain an aluminum alloy rod with a good match between strength and conductivity. The performance comparison between Comparative Example 2, Comparative Example 3 and Example 1 shows that not adding Zr will reduce the strength, and although adding excessive Zr will increase the strength, it will significantly reduce the conductivity. Figure 1 and Figure 2The metallographic images of Example 1 and Comparative Example 2 after extrusion show that, in Example 1 with an appropriate amount of Zr, the round aluminum rod prepared after hot extrusion did not undergo dynamic recrystallization, and the grain morphology exhibited an elongated fibrous structure. In contrast, in Comparative Example 2 without Zr, the round aluminum rod prepared after hot extrusion underwent complete dynamic recrystallization, resulting in coarse grains, which is unfavorable for forming slender grains and straight grain boundaries after cold deformation. The performance comparison between Comparative Examples 4 and 5 and Example 1 shows that the absence of Ce leads to a decrease in the strength of the aluminum rod, while the addition of excessive Ce reduces conductivity. The performance comparison between Comparative Examples 6 and 7 and Example 1 shows that the absence of Sr reduces the strength of the aluminum rod, while the addition of excessive Sr slightly reduces strength and significantly reduces conductivity. Figure 3 and Figure 4 The images shown are the as-cast scanning electron microscope (SEM) image and the energy spectrum of the intermediate phase (point A) of Example 1, respectively. It can be seen that the addition of appropriate amounts of Ce and Sr can produce a significant alteration effect on the iron-containing phase, making the morphology of the iron-containing CeSi rare earth compounds include needle-like, spherical, and short rod-like shapes, thereby improving the mechanical properties of the alloy.

[0091] Table 2 Tensile strength and conductivity of online solution-treated aluminum rods

[0092] Alloy elements Tensile strength / MPa Conductivity / % IACS Example 1 184 47.9 Example 2 188 47.1 Example 3 192 47.4 Example 4 198 46.8 Example 5 190 47.5 Comparative Example 1 167 48.1 Comparative Example 2 178 48.0 Comparative Example 3 193 45.3 Comparative Example 4 175 48.6 Comparative Example 5 188 45.1 Comparative Example 6 180 48.1 Comparative Example 7 179 46.5

[0093] As can be seen from Table 2, in the scheme designed in this invention, by reasonably proportioning the relative contents of Mg and Si, and adding appropriate amounts of Zr, Ce, and Sr, it is possible to ensure that the solid solution aluminum rod simultaneously possesses excellent electrical conductivity (greater than or equal to 47.1%) and tensile strength (e.g., greater than or equal to 184 MPa).

[0094] Since the products obtained in Examples 1-5 all have excellent strength, under these conditions, the best conductivity is used as the criterion for judgment. Therefore, the online solid solution aluminum rod of Example 1 is selected to prepare the conductor monofilament.

[0095] Example 6

[0096] This embodiment provides a method for preparing a high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material. A single wire is prepared using the following process. The tensile strength, elongation, room temperature electrical conductivity, and 90°C thermal conductivity of the single wire are tested to demonstrate the beneficial effects of the aluminum alloy material preparation method of this invention. The specific steps are as follows:

[0097] Step 1: Pre-age the online solution-treated aluminum rod of Example 1 at 175℃ for 20 minutes, and then perform low-temperature aging at 70℃ for 1 week;

[0098] Step 2: The pre-aged online solution-treated aluminum rod is cold-drawn. The pass processing rate is selected in the range of 10-35%, which decreases as the total deformation increases during operation (i.e., the processing rate of the first pass is a fixed value of more than 30%, and the processing rate of the second, third, fourth...nth passes decreases). The drawing speed is 10m / s, and a single wire with a diameter of 3.5mm is obtained.

[0099] Step 3: Heat the single wire to 170℃ at a rate of 3-5℃ / min and artificially age it for 6 hours to obtain the finished single wire. The properties of the obtained single wire are shown in Table 3.

[0100] Example 7

[0101] The process for preparing the conductor monofilament in this embodiment is completely the same as that in Example 6; the preparation parameters are completely the same except that the pre-aging regime used in this embodiment is 180℃ / 15min; the performance of the obtained conductor monofilament is shown in Table 3.

[0102] Example 8

[0103] The process for preparing the conductor monofilament in this embodiment is completely the same as that in Example 6; the preparation parameters are completely the same except that the aging regime used in this embodiment is 175℃ / 5h; the performance of the obtained conductor monofilament is shown in Table 3.

[0104] Example 9

[0105] The process for preparing the conductor monofilament in this embodiment is completely the same as that in Example 6; the preparation parameters are completely the same except that the aging regime used in this embodiment is 180℃ / 3.5h; the performance of the obtained conductor monofilament is shown in Table 3.

[0106] Comparative Example 8

[0107] The preparation of the conductor monofilament described in this comparative example differs from that in Example 6 only in that pre-aging and low-temperature aging were not performed; the other steps are the same. The properties of the obtained conductor monofilament are shown in Table 3.

[0108] Comparative Example 9

[0109] The preparation of the conductor monofilament described in this comparative example differs from that in Example 6 only in that low-temperature aging was not performed; the other steps are the same. The properties of the obtained conductor monofilament are shown in Table 3.

[0110] Comparative Example 10

[0111] The preparation of the conductor monofilament described in this comparative example differs from that in Example 6 only in that pre-aging was not performed; the other steps are the same. The properties of the obtained conductor monofilament are shown in Table 3.

[0112] Comparative Example 11

[0113] The preparation of the conductor monofilament described in this comparative example differs from that in Example 6 only in that the aging temperature is 150°C, while the other steps are the same; the properties of the obtained conductor monofilament are shown in Table 3.

[0114] Comparative Example 12

[0115] The preparation of the conductor monofilament described in this comparative example differs from that in Example 6 only in that the aging temperature is 210°C, while the other steps are the same; the properties of the obtained conductor monofilament are shown in Table 3.

[0116] Comparative Example 13

[0117] The preparation of the conductor monofilament described in this comparative example differs from that in Example 6 only in that the artificial aging time is 12 hours, while the other steps are the same; the properties of the obtained conductor monofilament are shown in Table 3.

[0118] The tensile strength, elongation, room temperature electrical conductivity, and 90℃ thermal conductivity of the single filament of the conductor were tested, and the results are shown in Table 3. The 90℃ thermal conductivity was first measured using a laser thermal conductivity meter to obtain the thermal diffusivity, and then calculated using equation (1).

[0119] λ=αρC P (1)

[0120] In the formula, λ is the thermal conductivity, α is the measured thermal diffusivity, and C P ρ is the specific heat capacity, and ρ is the measured density.

[0121] Table 3. Results of Monofilament Performance Tests

[0122]

[0123]

[0124] As shown in Table 3, the overall performance of Examples 6-9 is superior to that of Comparative Examples 8-13. The performance comparison between Comparative Example 8 and Example 6 shows that adding pre-aging and low-temperature aging processes can synergistically improve the strength, conductivity, and thermal conductivity of the conductor filaments; the performance comparison between Comparative Example 9 and Example 6 shows that adding a low-temperature aging process can synergistically improve the strength, conductivity, and thermal conductivity of the conductor filaments; the performance comparison between Comparative Example 10 and Example 6 shows that adding a pre-aging process can synergistically improve the strength, conductivity, and thermal conductivity of the conductor filaments; the performance comparison between Comparative Example 11 and Example 6 shows that when the aging temperature is below the lower limit of the set range, the conductor filament retains more strain-strengthening effect, resulting in higher strength, but lower elongation, conductivity, and thermal conductivity. Figure 5 and 6It can be seen that the number of reinforcing phases in the conductor filament described in Example 6 is significantly higher, indicating that artificial aging within the temperature range set in this invention results in more complete desolvation of Mg and Si elements, leading to an increase in electrical and thermal conductivity. A performance comparison between Comparative Example 12 and Example 6 shows that when the aging temperature exceeds the upper limit of the set temperature range, the elongation, electrical conductivity, and thermal conductivity of the conductor filament increase, but the filament strength decreases significantly. A performance comparison between Comparative Example 13 and Example 6 shows that when the aging time exceeds the upper limit of the aging time, the strength of the conductor filament decreases significantly.

[0125] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. A high-strength high-conductivity high-thermal-conductivity aluminum alloy material, characterized by: The aluminum alloy comprises the following components by weight percentage: Mg: 0.50~0.90 wt.%; Si: 0.40~0.65 wt.%; Zr: 0.05~0.20wt.%; Ce: 0.10~0.30 wt.%; Sr: 0.0005~0.01wt.%; The balance consists of Al and unavoidable impurity elements; The mass ratio of Mg to Si is 0.8 to 1.5; The high-strength, high-electrical-conductivity, and thermal-conductivity aluminum alloy material is prepared by the following method, which includes the following steps: aluminum melt boronizing, converter, smelting, casting, hot deformation, online solution treatment, pre-aging, low-temperature aging, cold deformation, and artificial aging. The pre-aging process involves heating the billet to 170-200°C at a rate of 3-5 K / min and holding it at that temperature for 10-60 min. After pre-aging, the billet is rapidly cooled to room temperature. The pre-aging process is performed after the billet has been quenched, with an interval of no more than 1 hour. The low-temperature aging temperature is 60~80℃, and the low-temperature aging time is 1~2 weeks; The artificial aging process involves heating the temperature to 170-200℃ at a rate of 3-5℃ / min and holding it at that temperature for 3-10 hours.

2. The high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material according to claim 1, characterized in that: The aluminum alloy comprises the following components by weight percentage: Mg: 0.55~0.80 wt.%; Si: 0.50~0.60 wt.%; Zr: 0.05~0.15wt.%; Ce: 0.15~0.25 wt.%; Sr: 0.001~0.005wt.%; The balance consists of Al and unavoidable impurity elements; wherein, among the unavoidable impurity elements, the residual content of element B is less than 0.01 wt.%, the content of element Fe is less than 0.10 wt.%, and the total content of elements Ti, V, Cr, and Mn is less than 0.010 wt.%.

3. The high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material according to claim 1, characterized in that: The aluminum melt boronizing process involves first heating the aluminum raw material to 780-850°C, then adding an Al-B master alloy for boronizing, and testing the Ti and V content of the boronized aluminum melt. When the Ti and V content is below 0.005 wt.%, the melt is then transferred to a converter. The smelting process involves controlling the temperature of the molten aluminum after the converter to 690~730℃, then sequentially adding Al-Si, Al-Zr, Al-Ce, Al-Sr, and Al-Mg master alloys. After the master alloys are completely melted, the mixture is stirred, degassed, refined, and its composition is adjusted, followed by settling of the molten aluminum. During degasting and refining, industrial pure N2 is used to blow the refining agent into the molten aluminum, and the amount of refining agent added is controlled to be 0.2~0.5 wt.% of the melt mass. The refining time is not less than 15 min. The casting method is selected from at least one of ordinary casting, semi-continuous casting, continuous casting, and die casting. The hot deformation is selected from at least one of hot rolling, hot extrusion, and hot continuous rolling.

4. The high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material according to claim 3, characterized in that: The hot rolling is carried out after the billet is homogenized. The entry temperature is 510~530℃, the rolling deformation is not less than 80%, and the exit temperature is not less than 540℃. The aluminum rod obtained is directly quenched into the cooling medium, and the cooling rate is greater than 100℃ / s.

5. The high-strength, high-conductivity, high-thermal-conductivity aluminum alloy material of claim 3, wherein: During hot continuous rolling, the temperature of the continuously cast billet is controlled at 520~550℃, the temperature of the mill emulsion is adjusted at 20~50℃, the pressure of the mill cooling water is 250~400kPa, the cooling water temperature is below 30℃, the deformation of hot continuous rolling is not less than 80%, and the exit temperature of the billet is below 60℃.

6. The high-strength, high-electrical-conductivity, and high-thermal-conductivity aluminum alloy material according to claim 3, characterized in that: The hot extrusion is carried out after the billet is homogenized. The extrusion temperature is 510~530℃, the extrusion deformation is not less than 80%, and the extruded aluminum rod is directly quenched into the cooling medium at a cooling rate greater than 100℃ / s.

7. The high-strength, high-conductivity, high-thermal-conductivity aluminum alloy material of claim 1, wherein: The cold deformation includes cold drawing, with a cold drawing pass rate of 10-35% and a drawing speed of 5-15 m / s, to obtain a conductor monofilament with a diameter of 2.5-4.0 mm.

8. The high-strength, high-conductivity, high-thermal-conductivity aluminum alloy material of claim 1, wherein: The artificial aging process involves holding the material for 3-6 hours, followed by air cooling.

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