Preparation method of high-conductivity and high-toughness Al-Fe alloy superfine electronic wire

Abstract

The invention belongs to the field of conductive aluminum alloy preparation and processing, and particularly relates to a preparation method of a high-conductivity and high-toughness Al-Fe alloy superfine electronic wire. The Al-Fe alloy material consists of the following elements in percentage by weight: 0.3-0.6% of iron, 0-0.04% of rare earth element lanthanum, 0-0.04% of rare earth element cerium, less than or equal to 0.1% of impurity elements and the balance of aluminum. And the Al-Fe alloy cast ingot is subjected to homogenization treatment, hot extrusion and continuous extrusion, and then the alloy round rod is prepared. The Al-Fe alloy rod is sequentially subjected to primary drawing, primary annealing, secondary drawing and secondary annealing, and the superfine Al-Fe alloy electronic wire with the characteristics of high conductivity and high elongation is prepared. The high-conductivity and high-toughness Al-Fe alloy superfine electronic wire prepared through the method is applied to a new energy automobile electronic wire harness in the future, on one hand, the endurance mileage of a new energy automobile can be remarkably increased, and on the other hand, the whole automobile cost of the new energy automobile can be greatly reduced.

Description

Technical Field

[0001] The invention belongs to the field of preparation and processing of conductive aluminum alloys, and in particular relates to a method for preparing a high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire. Background Art

[0002] Electronic wiring harnesses are called the nerves and blood vessels of new energy vehicles. With the trend of intelligent development of automobiles, the number of sensors in a single vehicle has increased rapidly, and the data transmission of sensors requires electronic wiring harnesses as a carrier. Therefore, the development of intelligent vehicles has greatly promoted the rapid growth of the demand for electronic wiring harnesses. Ultrafine metal electronic wires are an important component of electronic wiring harnesses, which play a role in power and signal transmission. Since copper has good electrical and mechanical properties, it is currently often used in electronic wiring harnesses of new energy vehicles. However, copper is a strategic resource, and its price has increased year by year, so the continued use of copper electronic wires will increase the cost of the whole vehicle. In addition to copper, aluminum also has good electrical conductivity and is often used as a conductor material. In addition, the density of aluminum is one-third of the density of copper. Using aluminum electronic wires to replace copper electronic wires will greatly reduce the weight of the whole vehicle, thereby increasing the cruising range of new energy vehicles. In addition, the price of aluminum is relatively lower, and the use of aluminum electronic wires in new energy vehicles can reduce the cost of the whole vehicle. Therefore, aluminum electronic wires have good application prospects instead of copper electronic wires, and at present, foreign car companies have adopted aluminum electronic wires as vehicle wiring harnesses and have achieved good expected results. Therefore, it will be a general trend for domestic car companies to adopt aluminum electronic wires. However, the research on aluminum alloy electronic wires in China started late, and the preparation technology of aluminum alloy electronic wires is relatively vacant. Therefore, it is urgent to carry out the research and development of aluminum alloy electronic wires. For electronic wires for new energy vehicles, conductivity and elongation are important performance indicators. High conductivity can reduce the line loss of electric energy, and high elongation can avoid breakage when the electronic wiring harness is bent. In summary, it is urgent to carry out the research and development of aluminum alloy electronic wires with both high conductivity and high toughness. Summary of the invention

[0003] The purpose of the present invention is to provide a method for preparing a high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire to meet the demand for high-conductivity and high-toughness electronic wires in the transportation field.

[0004] The technical solution of the present invention is:

[0005] A method for preparing a high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire comprises the following process steps:

[0006] (1) microalloying an Al-Fe melt with rare earth elements and fully purifying the melt with an inert gas or a refining agent, and then casting the melt into an Al-Fe alloy ingot;

[0007] (2) preparing the Al-Fe alloy round rod by homogenizing, hot extruding and continuously extruding the Al-Fe alloy ingot;

[0008] (3) subjecting the Al-Fe alloy round rod to primary drawing, primary annealing, secondary drawing and secondary annealing to obtain Al-Fe alloy ultrafine electronic wire;

[0009] The first drawing pass is 15 to 20 times, and the Al-Fe alloy fine wire is drawn to a diameter of 1.5 to 2.5 mm; the first annealing temperature is 300 to 400°C, kept warm for 5 to 60 minutes, and then air-cooled to room temperature; the second drawing pass is 20 to 25 times, and the Al-Fe alloy ultrafine wire is drawn to a diameter of 0.2 to 0.4 mm; the second annealing temperature is 350 to 450°C, kept warm for 0.5 to 30 minutes, and then air-cooled to room temperature.

[0010] The method for preparing the high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire is as follows: the element composition of the Al-Fe alloy material is as follows, by weight percentage: 0.3-0.6% iron, the Al-Fe alloy material contains rare earth elements lanthanum and / or cerium, the rare earth element lanthanum is 0-0.04%, the rare earth element cerium is 0-0.04%, the total amount of impurity elements is ≤0.1%, and the balance is aluminum.

[0011] In the method for preparing the high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire, in step (1), the preparation process of the Al-Fe alloy ingot is as follows:

[0012] (1) pure aluminum is placed in a smelting furnace for melting and a covering agent is added to the surface of the melt, and the melt temperature is adjusted to 740° C. to 770° C. The covering agent is a mixture of sodium chloride, potassium chloride and cryolite;

[0013] (2) adding iron to the melt in the form of pure iron or Al-Fe master alloy, stirring the melt thoroughly and keeping it warm for 30 minutes;

[0014] (3) Testing, analyzing and adjusting the melt composition to ensure that the content of each element is: iron 0.3-0.6%, the total amount of impurity elements ≤ 0.1%, and the balance is aluminum;

[0015] (4) Purifying the melt using an inert gas or a refining agent accounting for 0.2% of the melt weight;

[0016] (5) reducing the melt temperature to 700°C to 720°C;

[0017] (6) adding rare earth element cerium in the form of high-purity rare earth element cerium or Al-Ce master alloy to the melt, adding rare earth element lanthanum in the form of high-purity rare earth element lanthanum or Al-La master alloy to the melt, and then stirring the melt and keeping it warm for 10 minutes;

[0018] (7) Control the temperature at 700°C to 720°C, let it stand for 10 minutes, allow the slag or inclusions to float to the surface of the Al-Fe alloy melt, and remove the slag on the surface of the melt;

[0019] (8) The Al-Fe alloy melt is poured into a mold to obtain a highly conductive Al-Fe alloy ingot.

[0020] The method for preparing the high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire is as follows: during the heating, melting and heat preservation process of the Al-Fe alloy, an inert gas is filled into the smelting furnace for protection treatment to reduce the air absorption and oxidation of the melt.

[0021] The method for preparing the high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire strictly controls the hydrogen content in the Al-Fe alloy melt during the Al-Fe alloy smelting process, and before the rare earth element cerium is added to the Al-Fe alloy melt, the hydrogen content in the melt is lower than 0.15ml / 100g Al.

[0022] In the method for preparing the high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire, when the rare earth elements cerium and lanthanum are added in the form of pure metal, their purity is ≥99.9wt%; when the rare earth elements cerium and lanthanum are added in the form of Al-Ce master alloy and Al-La master alloy, the impurity element content in the Al-Ce master alloy and Al-La master alloy used is less than 0.1wt%.

[0023] The method for preparing the high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire, in step (2), the method for preparing the Al-Fe alloy round rod comprises the following steps:

[0024] (1) homogenizing the Al-Fe alloy ingot at 520-540° C. for 8-12 h;

[0025] (2) using a horizontal extruder to extrude the Al-Fe alloy ingot into a thick round rod at an extrusion temperature of 400 to 420° C.;

[0026] (3) The thick round rod is processed into an Al-Fe alloy round rod with a diameter of 8.5 to 10.5 mm by continuous extrusion.

[0027] The method for preparing the high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire adopts a continuous extruder for continuous extrusion processing, and the rotation speed of the continuous extruder is 12 to 16 revolutions per minute.

[0028] In the method for preparing the high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire, in step (3), the primary drawing process adopted is cold drawing, and the wire drawing speed is 30 to 50 m / min.

[0029] In the method for preparing the high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire, in step (3), the secondary drawing wire material is an Al-Fe alloy wire that has undergone a single annealing, and the wire drawing speed is 30 to 60 m / min.

[0030] The design principle and beneficial effects of the present invention are as follows:

[0031] 1. During the drawing process, as the amount of drawing deformation increases, the strength of the Al-Fe alloy wire increases and the elongation decreases. When the elongation cannot meet the requirements of drawing plastic deformation, a wire break accident will occur, resulting in the inability to draw continuously. The Al-Fe alloy wire needs to maintain a certain elongation to meet the requirements of the drawing process for plastic deformation. Therefore, the present invention first greatly improves the structural uniformity of the alloy round rod through aluminum liquid refining and continuous extrusion process, and reduces the gas content in the alloy to ensure that the alloy has excellent plastic deformation ability; secondly, after one drawing, an annealing is performed, the purpose is to recrystallize the grains in the Al-Fe alloy fine wire, restore the elongation, and ensure that the elongation meets the requirements of the secondary drawing. After the secondary drawing, the grains in the Al-Fe alloy ultrafine wire are severely refined, and there are a large number of defects such as dislocations and vacancies, which leads to a significant decrease in conductivity. In addition, the structural defects in the drawn Al-Fe alloy ultrafine wire will cause a significant decrease in the work hardening ability, resulting in a low elongation. Therefore, the purpose of secondary annealing after secondary drawing is to improve the conductivity and elongation of the Al-Fe alloy wire, to achieve the regulation of the conductivity and elongation of the Al-Fe alloy ultrafine electronic wire, and then to prepare high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire.

[0032] 2. Beneficial effects: The present invention can prepare ultrafine Al-Fe alloy electronic wires with both high conductivity and high toughness properties through the matching design of the full-process preparation process of Al-Fe alloy wires. In the future, the high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wires prepared by the present invention will be applied to electronic wiring harnesses of new energy vehicles. On the one hand, it can significantly improve the cruising range of new energy vehicles, and on the other hand, it can greatly reduce the vehicle cost of new energy vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The present invention is a process flow chart of drawing and annealing of high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire. DETAILED DESCRIPTION

[0034] In the specific implementation process, the high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire of the present invention is composed of the following elements in weight percentage: iron 0.3-0.6%, rare earth element lanthanum 0-0.04%, rare earth element cerium 0-0.04%, the total amount of impurity elements ≤0.1%, and the balance is aluminum.

[0035] The method for preparing high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire comprises the following steps:

[0036] (1) pure aluminum is melted in a smelting furnace and a covering agent (a mixture of sodium chloride, potassium chloride and cryolite) is added to the surface of the melt, and the melt temperature is adjusted to 740°C to 770°C;

[0037] (2) adding iron to the melt in the form of pure iron or Al-Fe master alloy, fully stirring the melt and keeping it warm for about 30 minutes, and then purifying the melt with an inert gas or a refining agent;

[0038] (3) Testing, analyzing and adjusting the melt composition so that the weight percentage of each element is: iron 0.3-0.6%, the total amount of impurity elements ≤ 0.1%, and the balance is aluminum;

[0039] (4) Purifying the melt using high-purity argon (99.999% by volume purity) or a refining agent accounting for 0.2% by weight of the melt;

[0040] (5) reducing the melt temperature to 700°C to 720°C;

[0041] (6) adding rare earth element cerium in the form of high-purity rare earth element cerium (purity ≥ 99.9 wt%) or Al-Ce master alloy to the melt, adding rare earth element lanthanum in the form of high-purity rare earth element lanthanum (purity ≥ 99.9 wt%) or Al-La master alloy to the melt, and then stirring the melt and keeping it warm for about 10 minutes;

[0042] (7) Control the temperature at 700°C to 720°C, let it stand for about 10 minutes, allow the slag or inclusions to float to the surface of the Al-Fe alloy melt, and remove the slag on the surface of the melt;

[0043] (8) The Al-Fe alloy melt is poured into a mold to obtain a highly conductive Al-Fe alloy ingot.

[0044] (9) homogenizing the Al-Fe alloy ingot at 520-540° C. for 8-12 h;

[0045] (10) using a horizontal extruder to extrude the ingot into a round rod at a temperature of 400 to 420° C.;

[0046] (11) The aluminum round rod is processed into a round rod with a diameter of 8.5 to 10.5 mm by continuous extrusion, and the speed of the continuous extruder is 12 to 16 revolutions per minute.

[0047] (12) Al-Fe alloy round rods are drawn once to obtain Al-Fe alloy fine wires with a diameter of 1.5 to 2.5 mm. The drawing process is cold drawing, the number of drawing passes is 15 to 20, and the wire drawing speed is 30 to 50 m / min.

[0048] (13) After the first drawing, the Al-Fe alloy wire is annealed at a temperature of 300-400°C for a holding time of 5-60 min, and then cooled to room temperature by air cooling.

[0049] (14) The Al-Fe alloy fine wire after the primary annealing is subjected to secondary drawing to obtain an Al-Fe alloy ultrafine wire with a diameter of 0.2 to 0.4 mm, the number of drawing passes is 20 to 25, and the wire drawing speed is 30 to 60 m / min;

[0050] (15) After secondary drawing, the Al-Fe alloy ultrafine wire is subjected to secondary annealing at a temperature of 350-450°C for a holding time of 0.5-30 min, and then cooled to room temperature by air cooling.

[0051] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other examples improved or modified by ordinary technicians in this field belong to the scope of protection of the present invention. It should be understood that the embodiments of the present invention are only used to illustrate the technical effects of the present invention, rather than to limit the scope of protection of the present invention. In the embodiments, the methods used are conventional methods unless otherwise specified.

[0052] Example 1

[0053] In this embodiment, the chemical composition of the Al-Fe alloy used in the high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire is: Fe 0.6wt.%, Ce 0.04wt.%, the total amount of impurity elements 0.02wt.%, and the balance is Al.

[0054] In this embodiment, the preparation method of high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire is as follows:

[0055] (1) pure aluminum is placed in a smelting furnace for melting and a covering agent is added to the surface of the melt, wherein the covering agent is a mixture of sodium chloride, potassium chloride and cryolite in a weight ratio of 2:2:1. The melt temperature is adjusted to 760°C. Iron is added to the melt in the form of pure iron or Al-Fe master alloy. The melt is fully stirred and kept warm for about 30 minutes. The melt is then purified using high-purity argon (99.999% by volume purity) or a common aluminum alloy refining agent accounting for 0.2% of the melt weight. The melt temperature is lowered to 710°C. Rare earth element cerium is added to the melt in the form of Al-Ce master alloy. The melt is stirred and kept warm for about 10 minutes. The temperature is controlled at 710°C and allowed to stand for 10 minutes to allow slag or inclusions to float to the surface of the aluminum alloy melt. The slag on the surface of the melt is removed. The alloy melt is poured into a mold to obtain a highly conductive Al-Fe alloy ingot.

[0056] (2) homogenizing the Al-Fe alloy ingot at 540°C for 8 h;

[0057] (3) using a horizontal extruder to extrude the ingot into a round rod at a temperature of 400°C;

[0058] (4) The round rod is processed into a round rod of 8.5 to 10.5 mm by continuous extrusion, and the continuous extruder speed is 12 revolutions per minute.

[0059] like Figure 1 As shown, the further drawing-annealing process is as follows:

[0060] (5) Drawing an Al-Fe alloy rod with a diameter of 9.5 mm in one drawing process. The drawing process is cold drawing. The number of drawing passes is 18. The die diameter of each pass is 8.5 mm → 7.6 mm → 6.7 mm → 5.9 mm → 5.2 mm → 4.8 mm → 4.4 mm → 4.0 mm → 3.7 mm → 3.4 mm → 3.1 mm → 2.9 mm → 2.7 mm → 2.5 mm → 2.4 mm → 2.3 mm → 2.2 mm → 2.1 mm. The wire drawing speed is 40 m / min. Al-Fe alloy fine wire with a diameter of 2.1 mm is obtained by drawing.

[0061] (6) primary annealing, wherein the Al-Fe alloy fine wire with a diameter of 2.1 mm after primary drawing is annealed at 380°C for 60 min, and the cooling method is air cooling;

[0062] (7) secondary drawing, drawing the Al-Fe alloy fine wire after the primary annealing, the drawing process is cold drawing, the drawing passes are 22, the die diameter of each pass is 2.0mm→1.8mm→1.6mm→1.4mm→1.2mm→1.1mm→1.0mm→0.9mm→0.8mm→0.75mm→0.7mm→0.65mm→0.6mm→0.55mm→0.5mm→0.45mm→0.4mm→0.36mm→0.32mm→0.28mm→0.24mm→0.20mm, the wire drawing speed is 50m / min, and the Al-Fe alloy ultrafine wire with a diameter of 0.20mm is obtained by drawing;

[0063] (8) Secondary annealing: The Al-Fe alloy ultrafine wire with a diameter of 0.20 mm obtained by secondary drawing is annealed at 400°C for 5 min and cooled in air to complete the preparation of high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire.

[0064] Example 2

[0065] The difference from Example 1 is that Figure 1 As shown, the drawing-annealing process is as follows:

[0066] (1) Drawing an Al-Fe alloy rod with a diameter of 9.0 mm in one drawing process. The drawing process is cold drawing. The number of drawing passes is 17. The die diameter of each pass is 8.0 mm → 7.0 mm → 6.5 mm → 6.0 mm → 5.5 mm → 5.0 mm → 4.5 mm → 4.0 mm → 3.5 mm → 3.1 mm → 2.8 mm → 2.5 mm → 2.3 mm → 2.2 mm → 2.1 mm → 2.0 mm → 1.9 mm. The wire drawing speed is 35 m / min. Al-Fe alloy fine wire with a diameter of 1.9 mm is obtained by drawing.

[0067] (2) primary annealing, in which the Al-Fe alloy fine wire with a diameter of 1.9 mm after primary drawing is annealed at 400°C for 40 minutes, and the cooling method is air cooling;

[0068] (3) secondary drawing, drawing the Al-Fe alloy wire after the primary annealing, the drawing process is cold drawing, the drawing passes are 21, the die diameter of each pass is 1.7mm→1.5mm→1.3mm→1.2mm→1.1mm→1.0mm→0.9mm→0.8mm→0.75mm→0.7mm→0.65mm→0.6mm→0.55mm→0.5mm→0.45mm→0.4mm→0.36mm→0.32mm→0.28mm→0.24mm→0.20mm, the wire drawing speed is 60m / min, and the Al-Fe alloy ultrafine wire with a diameter of 0.20mm is obtained by drawing;

[0069] (4) Secondary annealing: The Al-Fe alloy ultrafine electronic wire with a diameter of 0.20 mm obtained by secondary drawing is annealed at 450°C for 3 min and cooled in air to complete the preparation of high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire.

[0070] Comparative Example 1

[0071] The difference from Example 1 is that:

[0072] (1) The designed Al-Fe alloy composition is, by element weight percentage, Fe 0.58wt.%, La 0.02wt.%, total impurity elements 0.01wt.%, and the balance is Al;

[0073] (2) The hot extruded round rod is subjected to subsequent drawing-annealing process without continuous extrusion treatment.

[0074] Comparative Example 2

[0075] Steps (1) to (4) are the same as those in Example 1, except that:

[0076] An Al-Fe alloy rod with a diameter of 9.5 mm is drawn in one drawing process. The drawing process is cold drawing. The number of drawing passes is 21. The diameter of the die in each pass is 8.5 mm → 7.6 mm → 6.7 mm → 5.9 mm → 5.2 mm → 4.8 mm → 4.4 mm → 4.0 mm → 3.7 mm → 3.4 mm → 3.1 mm → 2.9 mm → 2.7 mm → 2.5 mm → 2.4 mm → 2.3 mm → 2.2 mm → 2.1 mm → 2.0 mm → 1.8 mm → 1.6 mm. The wire drawing speed is 40 m / min. An Al-Fe alloy wire with a diameter of 1.6 mm is obtained by drawing. When the diameter is 1.6 mm, the Al-Fe alloy wire is frequently broken due to continued drawing, and the drawing process cannot be continued. Finally, the Al-Fe alloy ultrafine wire cannot be prepared.

[0077] In the primary annealing, the Al-Fe alloy fine wire with a diameter of 1.6 mm after the primary drawing is subjected to an annealing treatment at 380° C. for 60 minutes, and the cooling method is air cooling.

[0078] Comparative Example 3

[0079] The difference from Comparative Example 2 is that the Al-Fe alloy fine wire with a diameter of 1.6 mm prepared by one-time drawing is not subjected to annealing treatment.

[0080] Comparative Example 4

[0081] Steps (1) to (7) are the same as those in Example 1, and Al-Fe alloy ultrafine wires with a diameter of 0.2 mm are prepared, except that no secondary annealing treatment is performed.

[0082] The mechanical properties and electrical conductivity of the Al-Fe alloy ultrafine electronic wires prepared in Example 1, Example 2 and Comparative Example 1 were tested, and the results are summarized in Table 1. It can be seen from Table 1 that the Al-Fe alloy ultrafine electronic wires prepared by the present invention have both good electrical conductivity and elongation, and the elongation of Comparative Example 1 is significantly lower. The performance test results of Example 1, Comparative Example 2 and Comparative Example 3 show that the Al-Fe alloy ultrafine wire cannot be prepared by drawing once without an intermediate annealing process. In addition, the performance test results of Comparative Example 3 show that although the strength of the Al-Fe alloy fine wire without secondary annealing is high, the elongation is greatly reduced, and it cannot meet the performance requirements of elongation during assembly and service of ultrafine electronic wires; the test results of Example 1 and Comparative Example 4 show that Al-Fe alloy ultrafine wires with a diameter of 0.2 mm can be prepared after one drawing, one annealing and two drawing, but no secondary annealing is performed, resulting in a low elongation of the Al-Fe alloy ultrafine wire, which cannot meet the elongation requirements during assembly and service of ultrafine electronic wires.

[0083] Table 1 Performance test results of Al-Fe alloy ultrafine electronic wires of Example 1, Example 2 and Comparative Example 1

[0084] Al-Fe alloy electronic wire Electronic wire diameter / mm Tensile strength / MPa Electrical conductivity / IACS% Elongation / % Example 1 0.2 126.3 62.23 16.7 Example 2 0.2 109.7 62.38 22.4 Comparative Example 1 0.2 115.2 61.53 14.2 Comparative Example 2 1.6 120.5 62.03 13.7 Comparative Example 3 1.6 198.5 61.85 2.5 Comparative Example 4 0.2 210.5 61.77 3.1

[0085] The implementation results show that the present invention prepares Al-Fe alloy round rods by homogenizing, hot extruding and continuously extruding Al-Fe alloy ingots, and sequentially subjects the Al-Fe alloy round rods to primary drawing, primary annealing, secondary drawing and secondary annealing, thereby preparing ultrafine Al-Fe alloy electronic wires with both high conductivity and high elongation characteristics.

Claims

1. A method for preparing high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire, characterized in that: The process steps include: (1) microalloying an Al-Fe melt with rare earth elements and fully purifying the melt with an inert gas or a refining agent, and then casting the melt into an Al-Fe alloy ingot; (2) preparing the Al-Fe alloy round rod by homogenizing, hot extruding and continuously extruding the Al-Fe alloy ingot; (3) subjecting the Al-Fe alloy round rod to primary drawing, primary annealing, secondary drawing and secondary annealing to obtain Al-Fe alloy ultrafine electronic wire; The first drawing pass is 15 to 20 times, and the Al-Fe alloy fine wire is drawn to a diameter of 1.5 to 2.5 mm; the first annealing temperature is 300 to 400°C, kept warm for 5 to 60 minutes, and then air-cooled to room temperature; the second drawing pass is 20 to 25 times, and the Al-Fe alloy ultrafine wire is drawn to a diameter of 0.2 to 0.4 mm; the second annealing temperature is 350 to 450°C, kept warm for 0.5 to 30 minutes, and then air-cooled to room temperature.

2. The method for preparing high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire according to claim 1, characterized in that: The element composition of the Al-Fe alloy material is as follows, by weight percentage: 0.3-0.6% iron, the Al-Fe alloy material contains rare earth elements lanthanum and / or cerium, the rare earth element lanthanum is 0-0.04%, the rare earth element cerium is 0-0.04%, the total amount of impurity elements is ≤0.1%, and the balance is aluminum.

3. The method for preparing high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire according to claim 1 or 2, characterized in that: In step (1), the preparation process of the Al-Fe alloy ingot is as follows: (1) pure aluminum is placed in a smelting furnace for melting and a covering agent is added to the surface of the melt, and the melt temperature is adjusted to 740° C. to 770° C. The covering agent is a mixture of sodium chloride, potassium chloride and cryolite; (2) adding iron to the melt in the form of pure iron or Al-Fe master alloy, stirring the melt thoroughly and keeping it warm for 30 minutes; (3) Testing, analyzing and adjusting the melt composition to ensure that the content of each element is: iron 0.3-0.6%, the total amount of impurity elements ≤ 0.1%, and the balance is aluminum; (4) Purifying the melt using an inert gas or a refining agent accounting for 0.2% of the melt weight; (5) reducing the melt temperature to 700°C to 720°C; (6) adding rare earth element cerium in the form of high-purity rare earth element cerium or Al-Ce master alloy to the melt, adding rare earth element lanthanum in the form of high-purity rare earth element lanthanum or Al-La master alloy to the melt, and then stirring the melt and keeping it warm for 10 minutes; (7) Control the temperature at 700°C to 720°C, let it stand for 10 minutes, allow the slag or inclusions to float to the surface of the Al-Fe alloy melt, and remove the slag on the surface of the melt; (8) The Al-Fe alloy melt is poured into a mold to obtain a highly conductive Al-Fe alloy ingot.

4. The method for preparing high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire according to claim 3, characterized in that: During the heating, melting and insulation process of Al-Fe alloy, the smelting furnace is filled with inert gas for protection treatment to reduce the inhalation and oxidation of the melt.

5. The method for preparing high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire according to claim 3, characterized in that: During the Al-Fe alloy smelting process, the hydrogen content in the Al-Fe alloy melt is strictly controlled. Before the rare earth element cerium is added to the Al-Fe alloy melt, the hydrogen content in the melt is lower than 0.15 ml / 100 g Al.

6. The method for preparing high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire according to claim 3, characterized in that: When the rare earth elements cerium and lanthanum are added in the form of pure metal, their purity is ≥99.9wt%; when the rare earth elements cerium and lanthanum are added in the form of Al-Ce master alloy and Al-La master alloy, the content of impurity elements in the Al-Ce master alloy and Al-La master alloy used is less than 0.1wt%.

7. The method for preparing high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire according to claim 1 or 2, characterized in that: In step (2), the method for preparing the Al-Fe alloy round rod comprises the following steps: (1) homogenizing the Al-Fe alloy ingot at 520-540° C. for 8-12 h; (2) using a horizontal extruder to extrude the Al-Fe alloy ingot into a thick round rod at an extrusion temperature of 400 to 420° C.; (3) The thick round rod is processed into an Al-Fe alloy round rod with a diameter of 8.5 to 10.5 mm by continuous extrusion.

8. The method for preparing high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire according to claim 7, characterized in that: A continuous extruder is used for continuous extrusion processing, and the rotation speed of the continuous extruder is 12 to 16 revolutions per minute.

9. The method for preparing high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire according to claim 1 or 2, characterized in that: In step (3), the primary drawing process adopted is cold drawing, and the wire drawing speed is 30 to 50 m / min.

10. The method for preparing high-conductivity and high-toughness Al-Fe alloy ultrafine electronic wire according to claim 1 or 2, characterized in that: In step (3), the secondary drawing wire material is an Al-Fe alloy wire that has undergone primary annealing, and the wire drawing speed is 30 to 60 m / min.

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