High-strength conductive aluminum-based micro-composite material and preparation method thereof

Abstract

The application discloses a kind of high-strength conductive aluminum-based micro-composite material and preparation method thereof, belong to aluminum alloy material processing technical field.The preparation method includes the following steps: using industrial pure aluminum, industrial silicon, magnesium and Al-8B-2C intermediate alloy as alloy raw materials for batching, wherein, the addition amount of industrial silicon is 0.6~0.8wt%, the addition amount of magnesium is 0.6~0.8wt%, the addition amount of Al-8B-2C intermediate alloy is 1~3wt%, and the rest is industrial pure aluminum;The alloy raw material is melted, cast, homogenization treatment, extrusion forming, solid solution treatment and aging treatment, namely obtained.The aluminum-based micro-composite material obtained by the above preparation method has good comprehensive performance, the tensile strength is higher than 310MPa, the elongation is higher than 10%, and the conductivity is higher than 52%IACS.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy material processing technology, and in particular to a high-strength conductive aluminum-based microcomposite material and its preparation method. Background Technology

[0002] The information disclosed in the background section of this invention is intended only to enhance the understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Due to the scarcity of copper resources in traditional conductors, aluminum-copper hybrids have become a hot topic in the conductor materials industry. Aluminum alloys, as conductor materials, possess advantages such as low density, good casting performance, low coefficient of thermal expansion, high specific strength, and high specific conductivity, making them the preferred material for power transmission lines in most countries worldwide. In my country, energy and load distribution is uneven. Coal resources are mostly concentrated in the Northwest and North China regions, while wind and solar energy resources are primarily located in the Northwest. Meanwhile, the central and eastern regions have large populations and developed economies, with electricity loads concentrated in these areas. The national "West-to-East Power Transmission" strategy is a crucial measure to transform the resource advantages of the western regions into economic advantages and promote the common economic development of the eastern and western regions. Consequently, the number of various types of overhead conductors in my country is increasing at an average annual rate of 10%, making high-strength, high-conductivity aluminum alloy conductors a much-needed power transmission material for the power industry. Traditional steel-cored aluminum stranded wire all-aluminum alloy conductors suffer from significant hysteresis and eddy current losses during transmission, and are prone to electrochemical corrosion between the steel core and aluminum wire, leading to increased energy consumption, reduced service life, and higher subsequent costs. Therefore, Al-Mg-Si series all-aluminum alloy conductors, which have high tensile strength, good sag characteristics, low loss, and long service life, have become the preferred material for long-distance power transmission projects.

[0004] Patent CN109295353A discloses a method for preparing high-strength, high-conductivity aluminum alloy wires. The preparation process is cumbersome and complex, and the elongation of the final aluminum alloy product is only 2.0-4.0%, which limits the application range of aluminum alloys. Summary of the Invention

[0005] In view of this, the present invention provides a high-strength conductive aluminum-based microcomposite material and its preparation method. The conductive aluminum-based microcomposite material prepared by the present invention can maintain a strength of more than 310 MPa, an elongation of more than 10%, and a conductivity of more than 52% IACS, and has good comprehensive performance.

[0006] In a first aspect, the present invention provides a method for preparing a high-strength conductive aluminum-based microcomposite material, comprising the following steps:

[0007] The alloy is formulated using industrial pure aluminum, industrial silicon, magnesium and Al-8B-2C master alloy as raw materials. The amount of industrial silicon added is 0.6 to 0.8 wt%, the amount of magnesium added is 0.6 to 0.8 wt%, the amount of Al-8B-2C master alloy added is 1 to 3 wt%, and the remainder is industrial pure aluminum.

[0008] The alloy raw materials are smelted, cast, homogenized, extruded, solution-treated, and aged to obtain the alloy.

[0009] Preferably, the specific steps of the smelting are as follows: industrial pure aluminum and industrial silicon are smelted at a temperature of 720-730°C, then Al-8B-2C master alloy is added and kept at a constant temperature for 20-40 minutes. When the temperature drops to 700-710°C, magnesium is added, and after stirring evenly, the temperature is raised to 730-750°C.

[0010] Furthermore, after stirring evenly and heating to 730–750°C, the mixture is refined and degassed using hexachloroethane, then slag is removed, and the mixture is allowed to stand and cool to 715–725°C.

[0011] Preferably, the casting step is: casting into bars at a temperature of 710-720°C.

[0012] Furthermore, before casting, the process includes preheating the casting mold to 300–350°C.

[0013] Preferably, the homogenization process involves subjecting the obtained bar to homogenization heat treatment at 555–565°C for 7–9 hours, followed by cooling to room temperature to obtain the homogenized bar.

[0014] Furthermore, the extrusion molding step involves processing the surface of the homogenized bar with a sheet, and then extruding it into a rod at 490–510°C with an extrusion ratio of 23–27:1.

[0015] Preferably, the solution treatment temperature is 540–560°C, and the solution treatment time is 1–3 hours.

[0016] Preferably, the aging treatment temperature is 170–180°C, and the aging treatment time is 7–9 hours.

[0017] Secondly, the present invention provides a high-strength conductive aluminum-based microcomposite material prepared by the above preparation method, wherein the high-strength conductive aluminum-based microcomposite material has a tensile strength higher than 310 MPa, an elongation higher than 10%, and a conductivity higher than 52% IACS.

[0018] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0019] This invention introduces an Al-8B-2C master alloy during the preparation process, which improves the strength of the aluminum-based microcomposite material. At the same time, boron plays a role in purifying the melt, thereby increasing the conductivity. In addition, the aluminum-based microcomposite material prepared after introducing the Al-8B-2C master alloy has an elongation of more than 10%. Therefore, this invention can obtain an aluminum-based microcomposite material with good comprehensive performance, and thus has broad application prospects. Detailed Implementation

[0020] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] This invention provides a method for preparing a high-strength conductive aluminum-based microcomposite material, comprising the following steps:

[0022] The alloy is formulated using industrial pure aluminum, industrial silicon, magnesium and Al-8B-2C master alloy as raw materials. The amount of industrial silicon added is 0.6 to 0.8 wt%, the amount of magnesium added is 0.6 to 0.8 wt%, the amount of Al-8B-2C master alloy added is 1 to 3 wt%, and the remainder is industrial pure aluminum.

[0023] The alloy raw materials are smelted, cast, homogenized, extruded, solution-treated, and aged to obtain the alloy.

[0024] In the alloy raw materials of this invention, Fe≤0.2wt%, Mn≤0.1wt%, Cu≤0.3wt%, Cr≤0.03wt%, Zn≤0.1wt%, and the total content of other impurities≤0.05wt%.

[0025] This invention introduces Al3BC particles and the AlB2 phase into the aluminum-based microcomposite material through the use of an Al-8B-2C master alloy during preparation. The Al3BC particles have a density similar to Al, a high elastic modulus, and good high-temperature stability, thus acting as a second-phase strengthening agent. Furthermore, the addition of the Al-8B-2C master alloy has a grain-refining effect, improving the overall strength of the aluminum-based microcomposite material. The AlB2 phase can react with impurity elements (such as Cr and V) in the alloy to form corresponding borides, converting the dissolved impurities into a combined state and removing them as slag, achieving a "purification" effect and improving conductivity. In addition, the introduction of the Al-8B-2C master alloy allows the final aluminum-based microcomposite material to have an elongation exceeding 10%. Therefore, this invention can yield an aluminum-based microcomposite material with excellent comprehensive properties and broad application prospects.

[0026] The specific smelting steps of this invention are as follows: industrial pure aluminum and industrial silicon are smelted at a temperature of 720–730°C, then an Al-8B-2C master alloy is added and held at that temperature for 20–40 minutes. When the temperature drops to 700–710°C, magnesium is added, stirred evenly, and then the temperature is raised to 730–750°C. This invention does not impose special limitations on the smelting equipment; commonly used smelting equipment in the field can be used. Preferably, a pit-type resistance furnace is selected. In this invention, when adding magnesium, it is placed below the surface of the alloy melt to allow it to integrate, thus preventing burn-off.

[0027] In this invention, after the stirring is homogenized and the temperature is raised to 730–750°C, hexachloroethane is used for refining and degassing, followed by slag removal and cooling to 715–725°C. This invention does not impose any special limitations on the refining, degassing, and slag removal steps; methods well-known in the art can be used.

[0028] In this invention, the casting step involves casting the material into bars at a temperature of 710–720°C. Before casting, the method further includes preheating the casting mold to 300–350°C. This invention does not impose special limitations on the casting process; commonly used casting methods and molds in the art can be employed. Preferably, a columnar graphite mold is used as the casting mold.

[0029] In this invention, the homogenization process involves subjecting the obtained bar stock to a homogenization heat treatment at 555–565°C for 7–9 hours, followed by cooling to room temperature to obtain a homogenized bar stock. After surface treatment with a sheeting process, the homogenized bar stock is extruded into rods at 490–510°C with an extrusion ratio of 23–27:1. This invention does not impose any particular limitations on the homogenization process and extrusion molding methods described above; any methods commonly used in the art can be employed.

[0030] The present invention does not impose any special restrictions on the solution treatment and aging treatment methods. The solution treatment temperature of the present invention is 540-560℃ and the solution treatment time is 1-3h. After the solution treatment, quenching treatment is performed immediately, and then aging treatment is performed at 170-180℃ for 7-9h.

[0031] The present invention also provides a high-strength conductive aluminum-based microcomposite material prepared by the above preparation method, wherein the high-strength conductive aluminum-based microcomposite material has a tensile strength higher than 310 MPa, an elongation higher than 10%, and a conductivity higher than 52% IACS.

[0032] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0033] Example 1

[0034] This embodiment provides a method for preparing a high-strength conductive aluminum-based microcomposite material, the specific steps of which are as follows:

[0035] (1) Industrial pure aluminum, industrial silicon, magnesium ingots and Al-8B-2C master alloy were used as alloy raw materials for batching. Among them, the amount of industrial silicon added was 0.74wt%, the amount of magnesium ingots added was 0.602wt%, the amount of Al-8B-2C master alloy added was 1wt%, and the remainder was industrial pure aluminum. The mass fractions of other components in the alloy raw materials were: Fe: 0.0746wt%, Mn: 0.0066wt%, Cu: 0.01wt%, Cr: 0.0049wt%, Zn: 0.002wt%.

[0036] (2) Smelting: Add industrial pure aluminum and industrial silicon to the electric resistance furnace and smelt at 725°C. Then, put the Al-8B-2C intermediate alloy into the aluminum alloy melt and keep it at a constant temperature for 30 minutes. When the temperature drops to 705°C, put the magnesium ingot below the surface of the melt to make it melt and prevent it from burning. Stir evenly and then raise the temperature to 740°C. Use hexachloroethane for refining and degassing, and remove the slag. Let the aluminum melt stand at a constant temperature of 720°C.

[0037] (3) Casting: Before casting, the columnar graphite mold is preheated to 320°C and cast into rods at 715°C.

[0038] (4) Homogenization treatment: The ingot rod is subjected to homogenization heat treatment at 560℃ for 8 hours, and then placed at room temperature.

[0039] (5) Hot extrusion: After the surface of the bar is coated, it is extruded into a rod at 500°C with an extrusion ratio of 25:1;

[0040] (6) Heat treatment: Solution treatment at 550℃ for 2 hours, followed immediately by quenching, and then artificial aging at 175℃ for 8 hours. The finished aluminum-based microcomposite material can be obtained after heat treatment.

[0041] Example 2

[0042] This embodiment provides a method for preparing a high-strength conductive aluminum-based microcomposite material, the specific steps of which are as follows:

[0043] (1) Industrial pure aluminum, industrial silicon, magnesium ingots and Al-8B-2C master alloy were used as alloy raw materials for batching. Among them, the amount of industrial silicon added was 0.702 wt%, the amount of magnesium ingots added was 0.616 wt%, the amount of Al-8B-2C master alloy added was 2 wt%, and the remainder was industrial pure aluminum. The mass fractions of other components in the alloy raw materials were: Fe: 0.0718 wt%, Mn: 0.0081 wt%, Cu: 0.01 wt%, Cr: 0.0064 wt%, Zn: 0.001 wt%.

[0044] (2) Smelting: Add industrial pure aluminum and industrial silicon to the electric resistance furnace and smelt at 725°C. Then, put the Al-8B-2C intermediate alloy into the aluminum alloy melt and keep it at a constant temperature for 30 minutes. When the temperature drops to 705°C, put the magnesium ingot below the surface of the melt to make it melt and prevent it from burning. Stir it evenly and then raise the temperature to 745°C. Use hexachloroethane for refining and degassing, and remove the slag. Let the aluminum melt stand at a constant temperature of 720°C.

[0045] (3) Casting: Before casting, the columnar graphite mold is preheated to 320°C and cast into rods at 715°C.

[0046] (4) Homogenization treatment: The ingot rod is subjected to homogenization heat treatment at 560℃ for 8 hours, and then placed at room temperature.

[0047] (5) Hot extrusion: After the surface of the bar is coated, it is extruded into a rod at 500°C with an extrusion ratio of 25:1;

[0048] (6) Heat treatment: Solution treatment at 550℃ for 2 hours, followed immediately by quenching, and then artificial aging at 175℃ for 8 hours. The finished aluminum-based microcomposite material can be obtained after heat treatment.

[0049] Example 3

[0050] This embodiment provides a method for preparing a high-strength conductive aluminum-based microcomposite material, the specific steps of which are as follows:

[0051] (1) Industrial pure aluminum, industrial silicon, magnesium ingots and Al-8B-2C master alloy were used as alloy raw materials for batching. Among them, the amount of industrial silicon added was 0.74wt%, the amount of magnesium ingots added was 0.614wt%, the amount of Al-8B-2C master alloy added was 3wt%, and the remainder was industrial pure aluminum. The mass fractions of other components in the alloy raw materials were: Fe: 0.0718wt%, Mn: 0.0073wt%, Cu: 0.03wt%, Cr: 0.0063wt%, Zn: 0.001wt%.

[0052] (2) Smelting: Add industrial pure aluminum and industrial silicon to the electric resistance furnace and smelt at 725°C. Then, put 3% Al-8B-2C master alloy into the aluminum alloy melt and keep it at a constant temperature for 30 minutes. When the temperature drops to 705°C, put magnesium ingots below the surface of the melt to make them melt and prevent them from burning. Stir evenly and then raise the temperature to 745°C. Use hexachloroethane for refining and degassing, and remove slag. Let the aluminum melt stand at a constant temperature of 720°C.

[0053] (3) Casting: Before casting, the columnar graphite mold is preheated to 320°C and cast into rods at 715°C.

[0054] (4) Homogenization treatment: The ingot rod is subjected to homogenization heat treatment at 560℃ for 8 hours, and then placed at room temperature.

[0055] (5) Hot extrusion: After the surface of the bar is coated, it is extruded into a rod at 500°C with an extrusion ratio of 25:1;

[0056] (6) Heat treatment: Solution treatment at 550℃ for 2 hours, followed immediately by quenching, and then artificial aging at 175℃ for 8 hours. The finished aluminum-based microcomposite material can be obtained after heat treatment.

[0057] The performance of the high-strength conductive aluminum-based microcomposite materials obtained in Examples 1-3 was measured and compared with that of aluminum alloy in patent CN109295353A, as shown in Table 1.

[0058] Table 1. Material property test data for various aluminum-based microcomposite materials

[0059]

[0060] As can be seen from the table above, the aluminum-based microcomposite materials provided in Examples 1 to 3 of the present invention have good comprehensive performance and the elongation is much better than that of CN109295353A.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of making a high-strength, electrically conductive aluminum-based microcomposite material, characterized by, It comprises the following steps: The alloy raw materials include industrial pure aluminum, industrial silicon, magnesium and Al-8B-2C intermediate alloy, wherein the addition amount of industrial silicon is 0.702-0.74wt%, the addition amount of magnesium is 0.602-0.616wt%, the addition amount of Al-8B-2C intermediate alloy is 1-3wt%, and the rest is industrial pure aluminum; in the alloy raw materials, Fe≤0.2wt%, Mn≤0.1wt%, Cu≤0.3wt%, Cr≤0.03wt%, Zn≤0.1wt%, and the total content of other impurities is ≤0.05wt%; The alloy raw materials are subjected to melting, casting, homogenization treatment, extrusion forming, solid solution treatment and aging treatment, and the high-strength conductive aluminum-based micro-composite material is obtained. The tensile strength of the high-strength conductive aluminum-based micro-composite material is higher than 310MPa, the elongation is higher than 10%, and the electrical conductivity is higher than 52%IACS.

2. The production method according to claim 1, wherein The specific steps of the melting are as follows: the industrial pure aluminum and the industrial silicon are melted at a temperature of 720-730℃, then the Al-8B-2C intermediate alloy is added and placed for 20-40min, when the temperature drops to 700-710℃, the magnesium is added, and after uniform stirring, the temperature is raised to 730-750℃.

3. The production method according to claim 2, wherein After the step of raising the temperature to 730-750℃ after uniform stirring, hexachloroethane is used for refining and degassing, and then the slag is removed, and the temperature is lowered to 715-725℃.

4. The production method according to claim 1, wherein The casting step is to cast into a rod at a temperature of 710-720℃.

5. The production method according to claim 4, wherein Before casting, the casting mold is preheated to 300-350℃.

6. The production method according to claim 4, wherein The homogenization treatment step is to heat treat the obtained rod at 555-565℃ for 7-9h, and then cool to room temperature to obtain the homogenized rod.

7. The production method according to claim 6, wherein The extrusion forming step is to extrude the homogenized rod into a rod at 490-510℃ after skin treatment, and the extrusion ratio is 23-27:

1.

8. The production method according to claim 1, wherein The solid solution treatment temperature is 540-560℃, and the solid solution time is 1-3h.

9. The production method according to claim 8, wherein The aging treatment temperature is 170-180℃, and the aging treatment time is 7-9h.

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