High-modulus high-conductivity heat-resistant aluminum alloy material, aluminum conductor, preparation method of aluminum conductor and power transmission cable

Abstract

The invention relates to the technical field of aluminum alloy wire processing, and particularly discloses a high-modulus high-conductivity heat-resistant aluminum alloy material, an aluminum wire, a preparation method and a power transmission cable. According to the high-modulus, high-conductivity and heat-resistant aluminum alloy material provided by the invention, the nanoscale TiB2 particles and the micron-sized SiC particles are compounded in the aluminum alloy powder, a dual-reinforcement system is constructed, and the mechanical property and the electrical property of an aluminum conductor are synergistically improved. The invention further provides a preparation method of the high-modulus and high-conductivity heat-resistant aluminum conductor. According to the process, a multi-stage coupling plastic processing technology of hot extrusion, continuous rolling, drawing and surface treatment is adopted. The grain structure is refined through the dynamic recrystallization effect in the series of machining processes, oxidation film defects on the surface and in the structure are damaged through plastic deformation, the rigidity and the conductivity of the aluminum wire are further optimized, and the technical bottleneck that high modulus, high conductivity and heat resistance of traditional aluminum alloy are difficult to consider at the same time is effectively solved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of aluminum alloy wire processing, and in particular to a high-modulus high-conductivity heat-resistant aluminum alloy material, an aluminum wire, a preparation method and a power transmission cable. BACKGROUND

[0002] With the rapid development of key fields such as 5C super-charging of new energy vehicles, extra-high voltage power transmission and new energy grid connection, the instantaneous high-power carrying capacity of the power transmission system on the wire is put forward with more stringent requirements. Under this background, the aluminum alloy wire with high modulus (≥90 GPa), high conductivity (≥61% IACS) and heat resistance (working temperature ≥125°C) has broad application potential in power transmission and new energy vehicle power loop scenes due to its unique performance advantages. Among them, the high modulus can significantly improve the bending deformation resistance of the wire, ensuring the structural stability of the wire in complex laying environment; the high conductivity can effectively reduce the energy loss in the current transmission process, meeting the energy saving and emission reduction demand; and the improvement of the heat resistance directly breaks through the power transmission upper limit of the traditional wire, which can adapt to higher load power consumption scenes. The synergistic effect of the three fundamentally solves the technical trade-off problem that the traditional aluminum alloy wire cannot simultaneously consider stiffness, conductivity and heat resistance.

[0003] However, current related researches mainly focus on realizing the single-dimensional improvement of the strength or heat resistance of the aluminum alloy wire through the regulation of alloy composition (such as the addition of alloy elements) or the optimization of the preparation process (such as heat treatment and rolling process), but such methods often cause a significant decrease in conductivity, forming a contradiction of “performance improvement-loss increase”. More importantly, the existing technology can only partially alleviate the inherent low modulus (insufficient stiffness) bottleneck of aluminum and its alloys, and cannot fundamentally break through this limitation. It is known that the elastic modulus of aluminum alloy is usually stable in the range of 68-79 GPa, and the existing alloying modification and process optimization technology cannot effectively improve the Young's modulus, resulting in the lack of effective technical solutions that can simultaneously improve the stiffness, conductivity and heat resistance of the aluminum alloy wire in the industry.

[0004] In summary, there is an urgent need in the field to develop a technical solution that can simultaneously improve the stiffness, conductivity and heat resistance of the aluminum alloy wire to break through the bottleneck of the existing technology and meet the use requirements of the comprehensive performance of the aluminum alloy wire under high requirements. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a high-modulus high-conductivity heat-resistant aluminum alloy material, an aluminum wire, a preparation method and a power transmission cable, which can solve the technical bottleneck that the existing aluminum alloy wire preparation process cannot simultaneously consider stiffness, conductivity and heat resistance.

[0006] To achieve the above technical purposes, the application provides a high-modulus high-conductivity heat-resistant aluminum alloy material, which comprises the following components in percentage by mass:

[0007] 0.5wt.%~5wt.% of nano-sized TiB2 particles, and the size of the nano-sized TiB2 particles is 100nm~1000nm;

[0008] 10wt.%~30wt.% of micron-sized SiC particles, and the size of the micron-sized SiC particles is 2um~100um;

[0009] The balance is aluminum alloy powder, and the particle size of the aluminum alloy powder is less than 5um.

[0010] Further, the aluminum alloy material further comprises at least one of the following components: 0.1wt.%~0.8wt.% of TiC; 0.05wt.%~0.5wt.% of B4C; 0.2wt.%~1.0wt.% of AlN; 0.15wt.%~0.7wt.% of Si3N4.

[0011] Further, the aluminum alloy powder comprises the following components in percentage by mass: 95.0wt.%~98.0wt.% of aluminum, 0.6wt.%~0.9wt.% of magnesium, 0.5wt.%~0.9wt.% of silicon, <0.10wt.% of copper, <0.50wt.% of iron, <0.03wt.% of manganese, <0.035wt.% of chromium, <0.10wt.% of zinc, <0.15wt.% of titanium, and the balance is impurities.

[0012] The application provides a preparation method of a high-modulus high-conductivity heat-resistant aluminum wire, which comprises the following steps:

[0013] Step S1, uniformly mixing the high-modulus high-conductivity heat-resistant aluminum alloy material, and performing pressing and sintering treatment to obtain an aluminum ingot blank;

[0014] Step S2, sequentially performing hot extrusion, continuous rolling, drawing, and surface treatment on the aluminum ingot blank to obtain the high-modulus high-conductivity heat-resistant aluminum wire.

[0015] Further, the hot extrusion temperature is 400~450℃.

[0016] Further, at least 5 continuous rolling processes are included, and the temperature of the continuous rolling process is 350~450℃.

[0017] Further, at least 3 drawing processes are included, and the deformation amount of single drawing is 5%~20%.

[0018] Further, the surface treatment includes scraping, cleaning and drying treatment until the surface of the aluminum wire is scratch-free, clean and dry, and the oxygen content is less than 0.1%.

[0019] The application provides a high-modulus high-conductivity heat-resistant aluminum wire, which is prepared from a high-modulus high-conductivity heat-resistant aluminum alloy material or by a preparation method of the high-modulus high-conductivity heat-resistant aluminum wire.

[0020] The application provides a power transmission cable, which comprises the high-modulus high-conductivity heat-resistant aluminum wire.

[0021] In summary, the application provides a high-modulus high-conductivity heat-resistant aluminum alloy material, which comprises the following components in percentage by mass: 0.5wt.%-5wt.% of nano-sized TiB2 particles, wherein the size of the nano-sized TiB2 particles is 100nm-1000nm; 10wt.%-30wt.% of micro-sized SiC particles, wherein the size of the micro-sized SiC particles is 2um-100um; and the balance is aluminum alloy powder, wherein the particle size of the aluminum alloy powder is less than 5um. The application combines the nano-sized TiB2 particles and the micro-sized SiC particles in the aluminum alloy powder to construct a double-reinforced system, so that the mechanical properties and the heat resistance of the aluminum wire are improved in coordination without impairing the inherent conductivity of the aluminum wire, and the technical bottleneck that the traditional aluminum alloy is difficult to have high modulus, high conductivity and heat resistance is effectively solved.

[0022] The application further provides a preparation method of the high-modulus high-conductivity heat-resistant aluminum wire, which adopts a multi-stage coupled plastic processing technology of "hot extrusion-continuous rolling-drawing-surface treatment". Through the series of processing, the dynamic recrystallization effect of the aluminum alloy material is promoted to further refine the grain structure, and the oxidation film defects on the surface and in the interior of the structure are damaged by plastic deformation, so that the rigidity and the conductivity of the aluminum wire are optimized.

[0023] Compared with the prior art, the application introduces the nano-sized TiB2 and the micro-sized SiC double-reinforced phases, utilizes the dispersion strengthening effect of the nano-phase and the bearing strengthening effect of the micro-phase, and improves the comprehensive service performance of the aluminum wire in coordination; and simultaneously, the multi-stage coupled plastic processing technology is adopted to effectively improve the interface bonding state between the reinforced particles and the aluminum alloy powder, and overcome the problem of processing and molding difficulty caused by particle agglomeration and weak interface bonding in the conventional composite system. DETAILED DESCRIPTION

[0024] The technical solutions of the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0026] Unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, and can be internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0027] Among them, all raw materials of the present application have no special restriction on their sources, and can be purchased on the market or prepared according to the conventional method well known to those skilled in the art.

[0028] The embodiment of the present application provides a high-modulus high-conductivity heat-resistant aluminum alloy material, which comprises the following components in percentage by mass:

[0029] 0.5wt.%~5wt.% of nano-sized TiB2 particles, and the size of the nano-sized TiB2 particles is 100nm~1000nm;

[0030] 10wt.%~30wt.% of micron-sized SiC particles, and the size of the micron-sized SiC particles is 2um~100um;

[0031] The balance is aluminum alloy powder, and the particle size of the aluminum alloy powder is less than 5um.

[0032] It should be noted that by compounding nano-sized TiB2 particles and micron-sized SiC particles in the aluminum alloy powder, a double reinforcement system is constructed, which can realize the synergistic improvement of the mechanical properties and heat resistance of the aluminum conductor without damaging the inherent conductivity of the aluminum conductor, and effectively solves the technical bottleneck that the traditional aluminum alloy is difficult to balance high modulus, high conductivity and heat resistance.

[0033] In some embodiments, in the aluminum alloy material, at least one of the following components is further included; 0.1wt.%~0.8wt.% of TiC; 0.05wt.%~0.5wt.% of B4C; 0.2wt.%~1.0wt.% of AlN; 0.15wt.%~0.7wt.% of Si3N4.

[0034] In some embodiments, the aluminum alloy powder comprises the following components in percentage by mass: 95.0wt.%~98.0wt.% of aluminum, 0.6wt.%~0.9wt.% of magnesium, 0.5wt.%~0.9wt.% of silicon, <0.10wt.% of copper, <0.50wt.% of iron, <0.03wt.% of manganese, <0.035wt.% of chromium, <0.10wt.% of zinc, <0.15wt.% of titanium, and the balance being impurities.

[0035] The embodiment of the present application provides a preparation method of high-modulus high-conductivity heat-resistant aluminum wire.

[0036] Step S1, uniformly mixing high-modulus high-conductivity heat-resistant aluminum alloy material, and performing pressing and sintering treatment to obtain an aluminum ingot blank.

[0037] Step S2, sequentially performing hot extrusion, continuous rolling, drawing and surface treatment on the aluminum ingot blank to obtain the high-modulus high-conductivity heat-resistant aluminum wire.

[0038] It should be noted that by adopting the multi-stage coupled plastic processing technology of "hot extrusion-continuous rolling-drawing-surface treatment", the dynamic recrystallization effect of the aluminum alloy material can be promoted to refine the grain structure, and the oxide film defects on the surface and in the interior of the structure can be damaged by plastic deformation, so that the rigidity and conductivity performance of the aluminum wire are further optimized.

[0039] In some embodiments, the high-modulus high-conductivity heat-resistant aluminum alloy material can be mixed in the form of ball milling.

[0040] In some preferred embodiments, the nano-TiB2 particles and the micron-sized SiC particles can be mixed with the aluminum alloy powder respectively, and then the mixtures of the two with the aluminum alloy powder are blended, and during the mixing process, a suitable ball milling speed can be selected according to actual needs. More specifically, the nano-TiB2 particles and the aluminum alloy powder are mixed by high-energy ball milling to obtain a first mixture; the micron-sized SiC particles and the aluminum alloy powder are mixed by low-speed ball milling to obtain a second mixture; and the first mixture and the second mixture are finally mixed by medium-speed ball milling.

[0041] In some embodiments, when the mixed aluminum alloy material is pressed and then sintered, the sintering temperature is 540℃~620℃, the sintering pressure is 20~100MPa, and the sintering time is 1~10h.

[0042] In some more preferred embodiments, when the mixed aluminum alloy material is pressed and then sintered, the sintering temperature is 580~610℃, the sintering pressure is 50~70MPa, and the sintering time is 2~6h.

[0043] It should be noted that this temperature range can promote the interface diffusion of aluminum alloy powder and nano-sized TiB2 particles and micron-sized SiC particles; this pressure range can act to inhibit the generation of pores during sintering. By regulating the sintering temperature and the synergistic effect of pressure, abnormal grain growth caused by excessively high temperature can be avoided, and densification can be promoted by moderate pressure, the holding time can be shortened to reduce the excessive generation of interface brittle phase, and the maximization of comprehensive performance can be realized.

[0044] In some embodiments, the hot extrusion temperature is 400-450°C.

[0045] It should be noted that the above temperature is in the thermal plastic deformation range of the aluminum alloy, which can reduce the material flow resistance to ensure the extrusion formability, and can refine the grains through dynamic recrystallization, while avoiding excessive reaction of the reinforcing particles and the matrix at high temperature to ensure the interface stability of the material.

[0046] In some embodiments, at least 5 continuous rolling processes are included, and the temperature of the continuous rolling process is 350-450°C.

[0047] In some preferred embodiments, the number of continuous rolling processes is 5-10 times.

[0048] It should be noted that multiple continuous rolling can accumulate plastic deformation to further break up coarse grains and promote uniform dispersion of particles, and the temperature range can maintain good plasticity of the material, reduce the risk of rolling cracks, and at the same time, improve the mechanical properties of the wire through dislocation strengthening and grain refinement. 5-10 times of continuous rolling process can balance between “refining effect” and “processing cost”: too little can not sufficiently refine the organization, and too much can cause the material plasticity to decrease due to work hardening, increasing the risk of cracking in subsequent drawing process.

[0049] In some embodiments, at least 3 drawing processes are included, and the deformation amount of a single drawing is 5%-20%.

[0050] It should be noted that the drawing of small deformation amount in several times can improve the density and strength of the material through “gradual accumulation of strain”, while avoiding local stress concentration (such as surface scratches and internal cracks) caused by single large deformation; the deformation range of 5%-20% takes into account the processing efficiency and material plasticity reserve, ensuring the stability of the size accuracy and mechanical properties of the aluminum wire.

[0051] In some embodiments, the surface treatment includes scraping, cleaning and drying treatment until the surface of the aluminum wire is scratch-free and clean and dry, and the oxygen content is less than 0.1%.

[0052] It should be noted that the scraping can remove the surface oxide layer and processing defects, and the cleaning and drying can eliminate residual impurities and moisture, and the low oxygen content state can effectively inhibit the surface oxidation corrosion in the subsequent use process, and protect the conductive performance and service life of the aluminum conductor.

[0053] The embodiment of the present application provides a high-modulus high-conductivity heat-resistant aluminum conductor, which is prepared from a high-modulus high-conductivity heat-resistant aluminum alloy material or obtained by a preparation method of the high-modulus high-conductivity heat-resistant aluminum conductor.

[0054] The embodiment of the present application provides a power transmission cable, which comprises the high-modulus high-conductivity heat-resistant aluminum conductor.

[0055] The applicant further provides the following reference specific embodiments for describing the present application, and it should be noted that the embodiments are merely descriptive and do not limit the present application in any way.

[0056] Embodiment 1

[0057] The embodiment provides a preparation method of a high-modulus high-conductivity heat-resistant aluminum conductor, and the specific steps are as follows:

[0058] In step S1, an aluminum alloy blank is prepared. Nanometer TiB2 particles and aluminum alloy powder with a particle size of less than 5 μm (the composition is consistent with that of 6201 aluminum alloy) are mixed by high-energy ball milling to obtain a first mixture; micron-sized SiC particles and aluminum alloy powder with a particle size of 5-50 μm are mixed by low-speed ball milling to obtain a second mixture; the first mixture and the second mixture are mixed by medium-speed ball milling to obtain the aluminum alloy blank; in the aluminum alloy blank, the mass percentage of TiB2 particles is 0.8 wt.%, and the particle size is 120 nm; the mass percentage of SiC particles is 15 wt.%, and the particle size is 10 um; the balance is aluminum alloy powder, and the particle size of the aluminum alloy powder is less than 5 μm;

[0059] In step S2, an aluminum ingot blank is prepared. The aluminum alloy blank is pressed by cold isostatic pressing, and then sintered in a hot isostatic pressing machine at a temperature of 580 DEG C and a pressure of 50 MPa for 2 h to obtain an aluminum ingot blank with a diameter of 300 mm;

[0060] In step S3, multi-stage coupled plastic processing is performed.

[0061] In step S3-1, hot extrusion processing is performed. The aluminum ingot blank is subjected to horizontal hot extrusion at a temperature of 450 DEG C to deform the aluminum ingot blank, and an aluminum alloy rod with a diameter of 25 mm is obtained.

[0062] In step S3-2, continuous rolling processing is performed. The aluminum alloy rod is subjected to 5 times of hot continuous rolling at a temperature of 400 DEG C to obtain an aluminum alloy rod with a diameter of 6 mm.

[0063] Step S3-3, multi-pass drawing: the aluminum alloy rod is drawn for 7 times at room temperature until an aluminum alloy intermediate conductor with a diameter of 3 mm is obtained, and the deformation of each drawing is 20%;

[0064] Step S3-4, surface treatment: the surface of the aluminum alloy intermediate conductor is sequentially subjected to scraping, cleaning and drying treatment until the surface of the aluminum alloy intermediate conductor is scratch-free, clean and dry, and the oxygen content is less than 0.1%, thereby obtaining an aluminum conductor.

[0065] Embodiments 2-3

[0066] Embodiments 2-3 respectively provide a preparation method of a high-modulus high-conductivity heat-resistant aluminum conductor, which is different from Embodiment 1 in that the content and particle size of TiB2 particles and SiC particles in the aluminum alloy blank are different, and the specific parameter setting conditions can be referred to Table 1.

[0067] Embodiment 4

[0068] The embodiment provides a preparation method of an aluminum conductor, which comprises the following preparation steps:

[0069] Step S1, aluminum alloy blank: nano-TiB2 particles and aluminum alloy powder with a particle size of less than 5 μm are mixed by high-energy ball milling to obtain a first mixture; micron-sized SiC particles and aluminum alloy powder with a particle size of 5-50 μm are mixed by low-speed ball milling to obtain a second mixture; the first mixture and the second mixture are mixed by medium-speed ball milling to obtain an aluminum alloy blank; in the aluminum alloy blank, the content of TiB2 particles is 0.8 wt.%, and the particle size is 120 nm; the content of SiC particles is 15 wt.%, and the particle size is 10 μm; the balance is aluminum alloy powder, and the particle size of the aluminum alloy powder is less than 5 μm;

[0070] Step S2, preparation of aluminum ingot blank; the aluminum alloy blank is pressed by cold isostatic pressing, and then sintered in a hot isostatic pressing machine at a temperature of 580 ℃ and a pressure of 50 MPa for 2 h to obtain an aluminum ingot blank with a diameter of 300 mm;

[0071] Step S3, aluminum ingot blank processing: the aluminum ingot blank is sent into a continuous rolling mill to be continuously rolled into an aluminum alloy rod with a diameter of 6 mm, and then subjected to drawing treatment to obtain an aluminum alloy conductor with a diameter of 3 mm.

[0072] Embodiments 5-6

[0073] Embodiments 5-6 respectively provide a preparation method of an aluminum conductor, which is different from Embodiment 4 in that the content and particle size of TiB2 particles and SiC particles in the aluminum alloy blank are different, and the specific parameter setting conditions can be referred to Table 1.

[0074] Comparative Example 1

[0075] The present comparative example provides a preparation method of an aluminum wire, which is different from Example 1 in that no TiB2 particles and SiC particles are added in the aluminum alloy blank.

[0076] Comparative Examples 2-7

[0077] The present comparative example provides a preparation method of an aluminum wire, which is different from Example 1 in that the content and particle size of TiB2 particles or SiC particles are different, and the specific parameter settings can be referred to Table 1.

[0078] Test: In order to clarify the influence of different reinforcing agents and processing technology on the performance of aluminum wire, the mechanical properties (GB / T228.1-2021), electrical properties (GB / T3048.2-2007) and working temperature (GB / T1179-2022) of the aluminum wires prepared in the above examples and comparative examples were tested, and the specific test results are shown in Table 1.

[0079] Table 1. Performance parameters of aluminum wires under different reinforcing agents or processing technologies

[0080]

[0081] The above is the preferred embodiment of the present application and is not intended to limit the present application, although the present application is described in detail with reference to the examples, those skilled in the art can still modify the technical solutions described in the foregoing examples or make equivalent replacement for part of the technical features, but any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A high-modulus, high-conductivity, and heat-resistant aluminum alloy material, characterized in that, The high-modulus, high-conductivity, and heat-resistant aluminum alloy material comprises the following components by weight percentage: 0.5 wt.% to 5 wt.% of nano-sized TiB2 particles, wherein the size of the nano-sized TiB2 particles is 100 nm to 1000 nm; 10wt.%~30wt.% of micron-sized SiC particles, wherein the size of the micron-sized SiC particles is 2µm~100µm; The remainder is aluminum alloy powder, and the particle size of the aluminum alloy powder is less than 5 μm.

2. The high-modulus, high-conductivity, heat-resistant aluminum alloy material according to claim 1, characterized in that, The aluminum alloy material also includes at least one of the following components; 0.1 wt.%~0.8 wt.% TiC; 0.05wt.%~0.5wt.% of B4C; 0.2 wt.%~1.0 wt.% AlN; 0.15wt.%~0.7wt.% of Si3N4.

3. The high-modulus, high-conductivity, heat-resistant aluminum alloy material according to claim 1, characterized in that, The aluminum alloy powder comprises the following components by weight percentage: 95.0 wt.% to 98.0 wt.% aluminum, 0.6 wt.% to 0.9 wt.% magnesium, 0.5 wt.% to 0.9 wt.% silicon, <0.10 wt.% copper, <0.50 wt.% iron, <0.03 wt.% manganese, <0.035 wt.% chromium, <0.10 wt.% zinc, <0.15 wt.% titanium, balance being impurities.

4. A method for preparing a high-modulus, high-conductivity, heat-resistant aluminum wire, characterized in that, Includes the following steps: Step S1: Mix the high modulus, high conductivity, and heat-resistant aluminum alloy material as described in any one of claims 1 to 3, and then press and sinter it to obtain an aluminum ingot billet. Step S2 involves sequentially hot extruding, continuous rolling, drawing, and surface treatment of the aluminum ingot to obtain a high-modulus, high-conductivity, heat-resistant aluminum wire.

5. The method for preparing high-modulus, high-conductivity, heat-resistant aluminum wire according to claim 4, characterized in that, The hot extrusion temperature is 400~450℃.

6. The method for preparing high-modulus, high-conductivity, heat-resistant aluminum wire according to claim 4, characterized in that, It includes at least 5 continuous rolling processes, the temperature of which is 350~450°C.

7. The method for preparing high-modulus, high-conductivity, heat-resistant aluminum wire according to claim 4, characterized in that, It includes at least three drawing processes, and the deformation of each drawing process is 5% to 20%.

8. The method for preparing high-modulus, high-conductivity, heat-resistant aluminum wire according to claim 4, characterized in that, The surface treatment includes scraping, cleaning, and drying until the aluminum conductor surface is free of scratches, clean, dry, and has an oxygen content of less than 0.1%.

9. A high-modulus, high-conductivity, heat-resistant aluminum wire, characterized in that, It is prepared using the high-modulus, high-conductivity, and heat-resistant aluminum alloy material as described in any one of claims 1 to 3, or obtained using the preparation method of the high-modulus, high-conductivity, and heat-resistant aluminum wire as described in any one of claims 4 to 8.

10. A power transmission cable, characterized in that, Including the high modulus, high conductivity, heat-resistant aluminum wire as described in claim 9.

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