High-strength high-conductivity copper alloy wire and method for manufacturing the same

Abstract

The application discloses a high-strength and high-conductivity copper alloy wire and a preparation method thereof, and belongs to the field of copper alloy preparation. Zr and Cr elements are added in the application, so that the number of Zr and net-shaped Cr reinforcing phases is increased, the grains are refined, the alloy is purified, the precipitation of the net-shaped Cr reinforcing phases is facilitated, the mechanical properties are obviously improved, and the conductivity and the processability of the material are ensured. B and Te are further added to generate nanoscale precipitated particles, so that the dislocations are pinned, the strength of the matrix is improved, and meanwhile, reasonable addition of La+Ge+Sm can reduce the problem that the strength and the hardness of the alloy with single-element addition increase with the addition of Cr and La, but the conductivity decreases.

Description

Technical Field

[0001] This invention relates to the field of copper alloy preparation methods, and more specifically, to a high-strength, high-conductivity copper alloy wire and its preparation method. Background Technology

[0002] High-strength, high-conductivity copper alloys are copper alloys with high room-temperature tensile strength and excellent electrical conductivity. Copper-based alloy materials are mainly used as resistance welding electrodes, lead frames, conductive bridges, and other materials in the automotive, motorcycle, electrical, electronics, and power industries. Domestically and internationally, these alloys are mainly divided into four categories according to their strength and conductivity: (1) High-strength, high-conductivity copper alloys, with tensile strength of 500-600 MPa and conductivity of 80-90% IACS; (2) Medium-strength, high-conductivity copper alloys, with tensile strength of 350-550 MPa and conductivity of 70-98% IACS; (3) High-strength, medium-conductivity copper alloys, with tensile strength of 700-800 MPa and conductivity of 40-50% IACS; (4) Ultra-high-strength, low-conductivity copper alloys, with tensile strength ≥900 MPa and conductivity of 10-30% IACS. Furthermore, due to their excellent comprehensive properties, high-strength, high-conductivity copper alloys are widely used in integrated circuits, high-voltage switches, and other fields. With the development of industries such as high-speed rail and long-distance power transmission, the demand for high-strength, high-conductivity copper alloys will continue to increase. For example, in copper alloys used in lead frames of large-scale integrated circuits, an ideal copper alloy is required to have a tensile strength greater than 600 MPa and an electrical conductivity of not less than 80% IACS to ensure its reliability and durability under load. How to effectively improve the strength of copper alloys without reducing their conductivity is also a key challenge in the current development of high-performance copper alloys.

[0003] For example, Chinese patent application CN201610401790.3 optimizes the design by modifying Cu-Cr-Zr rare earth elements with Cr content of 0.5-1.2% and improving the smelting process, which can significantly improve electrical conductivity, but the maximum tensile strength is only 502 MPa. Another example is Chinese patent application CN200810235978.0, which mainly changes the alloy's properties by adding different amounts and types of trace elements (Ni, Si, Ti), but the maximum tensile strength of the plate is 603 MPa, and the conductivity is 77% IACS; the tensile strength has not been significantly improved to meet market demands. Summary of the Invention

[0004] Based on this, in order to solve the problem that it is difficult to simultaneously improve the strength and conductivity of copper alloys in the prior art, the present invention provides a high-strength and high-conductivity copper alloy wire and its preparation method, the specific technical solution of which is as follows:

[0005] A high-strength, high-conductivity copper alloy wire, comprising the following components in weight percentage:

[0006] Zr 0.01%–0.05%, Cr 0.2%–0.5%, B 0.01%–0.03%, Te 0.01%–0.07%, Y₂O₃ 0.01%–0.03%, La 0.001%–0.009%, Ge 0.001%–0.003%, Sm 0.001%–0.008%, wherein La+Ge+Sm≤0.015%, and the balance is Cu and unavoidable impurities.

[0007] In addition, this application also provides a method for preparing a high-strength, high-conductivity copper alloy wire, the method being used to prepare the high-strength, high-conductivity copper alloy wire as described in claim 1, the method comprising the following steps:

[0008] Zr, Cr, B, Te and Cu raw materials are added to a smelting furnace and smelted to obtain mixture A;

[0009] Y2O3, La, Ge and Sm were added to the mixture A, and the mixture was further smelted, purified and cooled to obtain mixture B.

[0010] The mixture B was subjected to induced nucleation to obtain a semi-solid slurry;

[0011] The semi-solid slurry is cast to obtain an ingot;

[0012] The ingot is subjected to extrusion and annealing to obtain a bar stock;

[0013] The bar is subjected to heat treatment, cold forging, cold rotary forging, wire drawing, and aging treatment to obtain a high-strength, high-conductivity copper alloy wire.

[0014] Furthermore, the melting process is carried out at a temperature of 1300℃ to 1350℃ for 2 hours to 5 hours.

[0015] Furthermore, the purification process involves holding the temperature at 1150℃~1200℃ for 5min~10min after the temperature has been lowered, followed by degassing and slag removal.

[0016] Furthermore, the cooling rate for the induced nucleation is 300℃ / s to 500℃ / s.

[0017] Furthermore, the casting temperature is 1100℃~1150℃.

[0018] Furthermore, the extrusion processing pressure is 150MPa~160MPa, the speed is 20mm / s~25mm / s, and the heat preservation time of the extrusion molding die is 3min~5min.

[0019] Furthermore, the heat treatment temperature is 950℃~1000℃, and the time is 10min~20min.

[0020] Furthermore, the heat-treated bar is cold-forged to obtain a bar with a diameter of 40mm to 50mm. The bar is then subjected to multiple passes of cold rotary forging. During the cold rotary forging process, the deformation per pass is controlled at 18% to 22%. When the deformation of the bar reaches 60% to 70% during the cold rotary forging process, it is annealed in an anti-oxidation protective atmosphere at a temperature of 500℃ to 600℃ for 30 to 40 minutes to obtain a wire rod with a diameter of 4mm to 5mm.

[0021] Furthermore, the wire drawing process is unidirectional wire drawing, in which the wire is always drawn thinner in one direction, and the wire drawing speed is 10m / min to 500m / min.

[0022] The addition of Zr and Cr elements in the above scheme increases the amount of Zr and network Cr reinforcing phases, which helps refine the grains, purifies the alloy, and facilitates the precipitation of the network Cr reinforcing phase, significantly improving its mechanical properties while ensuring electrical conductivity and material machinability. The addition of B and Te generates nanoscale precipitates, which help improve the matrix strength through dislocation pinning. Furthermore, the appropriate addition of La+Ge+Sm can mitigate the problem of increased strength and hardness with the addition of Cr and La, but decreased electrical conductivity, often seen in alloys with single-element additions.

[0023] This application controls process parameters to ensure that elements are evenly distributed in the copper matrix, which helps to improve the uniformity of the microstructure and the quality of the ingot, and improves the processing performance of the alloy.

[0024] This application utilizes heat treatment, cold forging, cold rotary forging, wire drawing, and aging treatment to induce significant deformation in the material, generating substantial deformation heat. This leads to recovery and recrystallization of the alloy, repairing minor defects within the alloy. The combination of material and process slows down the deformation recovery and subsequent recrystallization process of the copper alloy, resulting in copper alloy wires with excellent strength and electrical conductivity. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to its embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of the invention.

[0026] Unless otherwise defined, 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. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0027] A high-strength, high-conductivity copper alloy wire according to one embodiment of the present invention comprises the following components in weight percentage:

[0028] Zr 0.01%–0.05%, Cr 0.2%–0.5%, B 0.01%–0.03%, Te 0.01%–0.07%, Y₂O₃ 0.01%–0.03%, La 0.001%–0.009%, Ge 0.001%–0.003%, Sm 0.001%–0.008%, wherein La+Ge+Sm≤0.015%, and the balance is Cu and unavoidable impurities.

[0029] In addition, this application also provides a method for preparing a high-strength, high-conductivity copper alloy wire, the method being used to prepare the high-strength, high-conductivity copper alloy wire as described in claim 1, the method comprising the following steps:

[0030] Zr, Cr, B, Te and Cu raw materials are added to a smelting furnace and smelted to obtain mixture A;

[0031] Y2O3, La, Ge and Sm were added to the mixture A, and the mixture was further smelted, purified and cooled to obtain mixture B.

[0032] The mixture B was subjected to induced nucleation to obtain a semi-solid slurry;

[0033] The semi-solid slurry is cast to obtain an ingot;

[0034] The ingot is subjected to extrusion and annealing to obtain a bar stock;

[0035] The bar is subjected to heat treatment, cold forging, cold rotary forging, wire drawing, and aging treatment to obtain a high-strength, high-conductivity copper alloy wire.

[0036] In one embodiment, the melting process is carried out at a temperature of 1300°C to 1350°C for 2 hours to 5 hours.

[0037] In one embodiment, the purification process involves waiting for the temperature to drop to 1150°C to 1200°C and then holding it at that temperature for 5 to 10 minutes, followed by degassing and slag removal.

[0038] In one embodiment, the cooling rate for the induced nucleation is 300°C / s to 500°C / s.

[0039] In one embodiment, the casting temperature is 1100°C to 1150°C.

[0040] In one embodiment, the extrusion pressure is 150MPa to 160MPa, the speed is 20mm / s to 25mm / s, and the heat preservation time of the extrusion molding die is 3min to 5min.

[0041] In one embodiment, the heat treatment temperature is 950°C to 1000°C and the time is 10 min to 20 min.

[0042] In one embodiment, the heat-treated bar is cold-forged to obtain a bar with a diameter of 40mm to 50mm. The bar is then subjected to multiple passes of cold rotary forging. During the cold rotary forging process, the deformation per pass is controlled to be 18% to 22%. When the deformation of the bar reaches 60% to 70% during the cold rotary forging process, it is annealed in an anti-oxidation protective atmosphere at a temperature of 500℃ to 600℃ for 30 to 40 minutes to obtain a wire rod with a diameter of 4mm to 5mm.

[0043] In one embodiment, the wire drawing process is unidirectional wire drawing, in which the wire is always drawn thinner in one direction, and the wire drawing speed is 10m / min to 500m / min.

[0044] In one embodiment, the aging process includes a first-level aging process and a second-level aging process. The first-level aging process is carried out at a temperature of 450°C to 500°C for 1 hour to 3 hours. The second-level aging process is carried out at a temperature of 520°C to 550°C for 1 hour to 3 hours.

[0045] The above solution, by optimizing the composition and process, can obtain copper alloy wire with high strength and high conductivity.

[0046] The implementation schemes of the present invention will now be described in detail with reference to specific embodiments.

[0047] Examples 1-3:

[0048] The components and composition of Examples 1-3 are shown in Table 1;

[0049] A method for preparing a high-strength, high-conductivity copper alloy wire includes the following steps:

[0050] Zr, Cr, B, Te and Cu raw materials were added to a melting furnace and melted at 1300℃ for 5 hours to obtain mixture A;

[0051] Y2O3, La, Ge and Sm were added to the mixture A, and the melting process was continued. After the temperature dropped to 1150℃, it was kept at the temperature for 5 minutes. Degassing and slag removal were performed, and the mixture B was obtained after cooling.

[0052] The mixture B was subjected to induced nucleation at a cooling rate of 350℃ / s to obtain a semi-solid slurry;

[0053] The semi-solid slurry was cast at 1150°C to obtain an ingot.

[0054] The ingot was subjected to extrusion and annealing under the conditions of a pressure of 150 MPa, a speed of 20 mm / s, and a holding time of 5 min in the extrusion die to obtain a bar.

[0055] The bar was heat-treated at 950°C for 20 minutes.

[0056] The heat-treated bar was cold-forged to obtain a bar with a diameter of 40 mm. Then, the bar underwent multiple passes of cold rotary forging, controlling the deformation per pass to 18%. When the deformation reached 60%, the bar was annealed for 30 minutes in an anti-oxidation protective atmosphere at 500°C to obtain a wire bar with a diameter of 4 mm. This wire was then drawn in one direction, with the wire always tapering in the same direction at a speed of 30 m / min. Finally, an aging treatment was performed, including a primary aging treatment at 450°C for 3 hours and a secondary aging treatment at 520°C for 2 hours, resulting in a high-strength, high-conductivity copper alloy wire.

[0057] Comparative Examples 1-5:

[0058] The difference between Comparative Examples 1-5 and Example 3 is that the components of Comparative Examples 1-5 are different from those of Example 3, while the rest are the same as those of Example 3, as shown in Table 1.

[0059] Comparative Example 6:

[0060] The difference between Comparative Example 6 and Example 3 is that the composition of Comparative Example 6 is different from that of Example 3. Specifically, 0.009% La + 0.003% Ge + 0.008% Sm = 0.02% > 0.015%, while the rest is the same as that of Example 3.

[0061] Comparative Example 7:

[0062] The difference between Comparative Example 7 and Example 3 is that Comparative Example 7 did not undergo heat treatment, but otherwise it was the same as Example 3.

[0063] Comparative Example 8:

[0064] The difference between Comparative Example 8 and Example 3 is that Comparative Example 8 did not undergo cold forging or cold rotary forging, but was otherwise the same as Example 3.

[0065] Comparative Example 9:

[0066] The difference between Comparative Example 9 and Example 3 is that Comparative Example 9 has undergone aging treatment, while the rest is the same as Example 3.

[0067] Comparative Example 10:

[0068] The difference between Comparative Example 10 and Example 3 is that Comparative Example 10 is a first-stage aging treatment, the temperature of which is 350°C and the time is 1 hour, while the rest is the same as Example 3.

[0069] Table 1: Ingredients and their proportions

[0070]

[0071] The copper alloy wires prepared in Examples 1-3 and the copper alloy wires prepared in Comparative Examples 1-10 were subjected to performance tests. Specifically, tensile strength and electrical conductivity were tested. The tensile strength test method was based on GB / T228.1-2010 "Metallic materials - Tensile testing - Part 1: Test at room temperature", and the electrical conductivity test method was based on GB / T3048.2-2007 "Electrical properties test method for wires and cables - Part 2: Test for resistivity of metallic materials". The results are shown in Table 2 below.

[0072] Table 2: Tensile Strength and Electrical Conductivity

[0073]

[0074]

[0075] Analysis of the data in Table 2 shows that, through optimization of composition and component ratio, this application can obtain copper alloy wires with high strength and conductivity. Specifically, the difference between Comparative Examples 1-6 and Example 3 lies in the different compositions and component ratios. However, it is evident that the tensile strength and yield strength of the prepared copper alloy wires are lower than those of Example 3, indicating that composition optimization can promote the acquisition of high-strength and high-conductivity products. The difference between Comparative Examples 7-10 and Example 3 lies in the different processes. However, the performance of the copper alloy wires obtained in Comparative Examples 7-10 is also worse than that of Example 3, demonstrating that, under the synergistic effect of composition and process, this application, as a complete technical solution, can obtain significantly superior high-strength and high-conductivity copper alloy wires.

[0076] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A high-strength, high-conductivity copper alloy wire, characterized in that, It includes the following components in percentage by mass: Zr 0.01%–0.05%, Cr 0.2%–0.5%, B 0.01%–0.03%, Te 0.01%–0.07%, Y₂O₃ 0.01%–0.03%, La 0.001%–0.009%, Ge 0.001%–0.003%, Sm 0.001%–0.008%, wherein La+Ge+Sm≤0.015%, and the balance is Cu and unavoidable impurities; The high-strength, high-conductivity copper alloy wire is prepared using the following methods: Zr, Cr, B, Te and Cu raw materials are added to a smelting furnace and smelted to obtain mixture A; Y2O3, La, Ge and Sm were added to the mixture A, and the mixture was further smelted, purified and cooled to obtain mixture B. The mixture B was subjected to induced nucleation to obtain a semi-solid slurry; The semi-solid slurry is cast to obtain an ingot; The ingot is subjected to extrusion and annealing to obtain a bar stock; The bar is subjected to heat treatment, cold forging, cold rotary forging, wire drawing, and aging treatment to obtain a high-strength, high-conductivity copper alloy wire.

2. A method for preparing a high-strength, high-conductivity copper alloy wire, characterized in that, The preparation method is used to prepare the high-strength, high-conductivity copper alloy wire as described in claim 1, and the preparation method includes the following steps: Zr, Cr, B, Te and Cu raw materials are added to a smelting furnace and smelted to obtain mixture A; Y2O3, La, Ge and Sm were added to the mixture A, and the mixture was further smelted, purified and cooled to obtain mixture B. The mixture B was subjected to induced nucleation to obtain a semi-solid slurry; The semi-solid slurry is cast to obtain an ingot; The ingot is subjected to extrusion and annealing to obtain a bar stock; The bar is subjected to heat treatment, cold forging, cold rotary forging, wire drawing, and aging treatment to obtain a high-strength, high-conductivity copper alloy wire.

3. The preparation method according to claim 2, characterized in that, The smelting process is carried out at a temperature of 1300℃ to 1350℃ for 2 hours to 5 hours.

4. The preparation method according to claim 2, characterized in that, The purification process involves waiting for the temperature to drop to 1150℃~1200℃ and then holding it at that temperature for 5min~10min, followed by degassing and slag removal.

5. The preparation method according to claim 2, characterized in that, The cooling rate for the induced nucleation is 300℃ / s to 500℃ / s.

6. The preparation method according to claim 2, characterized in that, The casting temperature is 1100℃~1150℃.

7. The preparation method according to claim 2, characterized in that, The extrusion processing pressure is 150MPa~160MPa, the speed is 20mm / s~25mm / s, and the heat preservation time of the extrusion molding die is 3min~5min.

8. The preparation method according to claim 2, characterized in that, The heat treatment temperature is 950℃~1000℃, and the time is 10min~20min.

9. The preparation method according to claim 2, characterized in that, The heat-treated bar is cold-forged to obtain a bar with a diameter of 40mm to 50mm. The bar is then subjected to multiple passes of cold rotary forging. During the cold rotary forging process, the deformation per pass is controlled at 18% to 22%. When the deformation of the bar reaches 60% to 70% during the cold rotary forging process, it is annealed in an anti-oxidation protective atmosphere at a temperature of 500℃ to 600℃ for 30 to 40 minutes to obtain a wire rod with a diameter of 4mm to 5mm.

10. The preparation method according to claim 9, characterized in that, The wire drawing process is unidirectional, and the wire is always drawn thinner in one direction during the drawing process. The wire drawing speed is 10m / min to 500m / min.

Images