Copper alloy material, preparation method thereof and copper wire prepared from copper alloy material

Abstract

The invention belongs to the technical field of copper alloy materials, and discloses a copper alloy material, a preparation method thereof and a copper wire prepared from the copper alloy material. The preparation method of the copper alloy material comprises the following steps that Ni elementary substance powder, Co elementary substance powder and Al elementary substance powder are mixed according to the molar ratio of (0.95-1.05): (0.95-1.05): (0.95-1.05) and then subjected to high-energy ball milling, Ni-Co-Al medium-entropy alloy micro powder is obtained, then vacuum arc melting or spark plasma sintering is conducted, and Ni-Co-Al medium-entropy alloy is obtained; and the Ni-Co-Al medium-entropy alloy, the tungsten-copper alloy and the copper ingot are mixed and smelted, and the copper alloy material is obtained. According to the invention, the copper ingot is used as a base material, the tungsten copper alloy is used as a reinforcing phase, the Ni-Co-Al medium entropy alloy is used as a binding phase, the copper alloy with high strength, corrosion resistance and electrical conductivity is prepared through conventional mixed smelting, and the copper alloy has the advantages of simple processing method and low production cost.

Description

Technical Field

[0001] This invention belongs to the field of copper alloy material technology, specifically relating to a copper alloy material, its preparation method, and copper wires prepared therefrom. Background Technology

[0002] Copper conductors are linear conductors made primarily of copper. Their conductivity is second only to silver, and they possess excellent corrosion resistance, making them a core material for power transmission and electronic equipment. However, pure copper alloy conductors have low mechanical strength, thus the development of copper conductors with higher mechanical strength holds significant market potential. Replacing pure copper with aluminum-copper alloys can improve conductor strength and reduce costs, but the addition of high aluminum content reduces conductivity and corrosion resistance in acidic or electrolyte environments.

[0003] Patent document CN 118595447 B discloses a high-strength copper alloy wire for new energy motors and its preparation method. It uses Fe-Co-Al medium-entropy alloy and Ni3Al alloy as reinforcing and binding phases to improve the metallographic structure of the copper-aluminum alloy, refine the alloy grains, and enhance the strength and conductivity of the copper-aluminum alloy. However, the introduction of Fe element reduces the corrosion resistance of the copper alloy wire, and the strength and corrosion resistance of aluminum alloy-reinforced copper wire still need further improvement to meet the demands of more demanding applications.

[0004] Copper-tungsten alloy wires play a vital role in various fields such as power and electronics due to their excellent conductivity, high temperature resistance, high stability, and reliability. However, the significant difference in the thermal expansion coefficients of copper and tungsten, coupled with the high melting point of tungsten, makes the processing of copper-tungsten alloy wires difficult and the production cost relatively high, which to some extent limits their widespread application. Summary of the Invention

[0005] In view of the shortcomings and deficiencies of the existing technology, the primary objective of this invention is to provide a method for preparing copper alloy materials.

[0006] Another object of the present invention is to provide a copper alloy material prepared by the above method.

[0007] Another object of the present invention is to provide a copper wire made using the above-mentioned copper alloy material.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A method for preparing a copper alloy material includes the following steps:

[0010] (1) Ni, Co and Al elemental powders were mixed in a molar ratio of 0.95~1.05:0.95~1.05:0.95~1.05 and then ball-milled at high energy to obtain Ni-Co-Al medium-entropy alloy micro powder;

[0011] (2) The obtained Ni-Co-Al medium-entropy alloy micro powder is subjected to vacuum arc melting or discharge plasma sintering to obtain Ni-Co-Al medium-entropy alloy;

[0012] (3) The Ni-Co-Al medium-entropy alloy is mixed and smelted with tungsten copper alloy and copper ingot to obtain copper alloy material.

[0013] Preferably, the average particle size of the Ni, Co, and Al elemental powders in step (1) is ≤50μm, and the purity is >99.9%.

[0014] Preferably, the high-energy ball milling in step (1) refers to ball milling for 4 to 12 hours under the conditions of a ball-to-material ratio of 8 to 15:1 and a rotation speed of 300 to 500 r / min.

[0015] Preferably, the temperature of vacuum arc melting in step (2) is 1200-1400℃; and the temperature of discharge plasma sintering is 1100-1200℃.

[0016] Preferably, the mass percentage ratio of the Ni-Co-Al medium-entropy alloy, tungsten-copper alloy and copper ingot mixed and smelted in step (3) is: 2% to 5% for Ni-Co-Al medium-entropy alloy, 5% to 25% for tungsten-copper alloy and 70% to 93% for copper ingot.

[0017] More preferably, the tungsten-copper alloy uses tungsten-copper alloy powder with a copper content ≥30% by mass and a particle size of 0.1–0.2 mm. This invention uses a tungsten-copper alloy with a copper content ≥30% by mass, which has good plasticity and can achieve a good bond between tungsten and copper under the smelting conditions of this invention. The tungsten-copper alloy powder is a conventional industrial raw material, prepared using powder metallurgy technology.

[0018] More preferably, the tungsten content in the copper alloy material is controlled to be 3% to 12% by mass. Too low a tungsten content has limited effect on improving strength and corrosion resistance, while too high a tungsten content leads to a poorer bonding effect with copper under conventional mixed smelting conditions, resulting in a comprehensive reduction in the improvement effect.

[0019] Preferably, the mixing and melting in step (3) is completed in a melting furnace at a temperature of 1400 to 1600°C.

[0020] Preferably, after melting in step (3), the mixture is further annealed at a temperature of 500–700°C.

[0021] A copper alloy material is prepared by the above method.

[0022] A copper wire made using the aforementioned copper alloy material.

[0023] The principle of this invention is as follows: Conventional tungsten-copper alloys are produced by powder metallurgy, with tungsten content as high as 50% to 90%. Directly using them to prepare wires is costly (low processing efficiency of powder metallurgy, high tungsten cost), difficult to process (high tungsten alloys have high melting points and poor plasticity), and has low conductivity (tungsten has high resistivity; the conductivity of tungsten-copper alloys produced by existing powder metallurgy methods is generally 30% to 60% IACS). This invention introduces a tungsten reinforcing phase by adding a tungsten-copper alloy through conventional mixing and melting methods, achieving good plastic mixing with the copper substrate. Simultaneously, a low-melting-point Ni-Co-Al medium-entropy alloy is used as a binder phase. Ni-Co-Al medium-entropy alloy has good fluidity in the molten state and good compatibility with both tungsten and copper. Through melt infiltration, it repairs defects at the copper-tungsten interface, improving alloy strength. Furthermore, the introduction of Ni-Co-Al has minimal impact on the corrosion resistance and conductivity of the copper alloy. Through these combined effects, high strength, high corrosion resistance, and high conductivity are simultaneously achieved.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] (1) The copper alloy material of the present invention is prepared by conventional mixing and melting with copper ingot as base material, tungsten copper alloy as reinforcing phase and Ni-Co-Al medium entropy alloy as binder phase. It has the advantages of simple processing method and low production cost.

[0026] (2) The copper alloy material of the present invention can significantly improve the strength and corrosion resistance of copper wires and maintain high conductivity. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0028] Example 1

[0029] A method for preparing a copper alloy wire includes the following steps:

[0030] (1) Ni, Co and Al elemental powders with an average particle size ≤50μm and a purity >99.9% were mixed at a molar ratio of 1:1:1 and added to a high-energy ball mill. The mixture was ball-milled for 8 hours at a ball-to-material ratio of 10:1 and a rotation speed of 400r / min to obtain Ni-Co-Al medium-entropy alloy micro powder.

[0031] (2) The obtained Ni-Co-Al medium-entropy alloy powder was added to a vacuum electric arc furnace for melting. The melting temperature was 1250-1300℃ and the melting time was 90min. After melting, the alloy was cooled with the furnace to obtain Ni-Co-Al medium-entropy alloy.

[0032] (3) By mass percentage, 4% Ni-Co-Al medium entropy alloy, 16% copper-containing 50wt% tungsten copper alloy powder (80 mesh) and 80% copper ingots are added to a horizontal furnace for smelting at a temperature of 1500-1550℃. The molten copper is cooled by a condenser and then pulled out by a traction mechanism. It is then annealed at 600-650℃ and cooled before being wound by a rewinding machine to obtain copper alloy wire.

[0033] The copper alloy wire obtained in this embodiment has a tensile strength of 356 MPa after tensile testing (GB / T 228-2010), and a corrosion resistance of level 9 after 24h acetic acid salt spray test (AASS) (based on the corrosion area rating established by GB / T6461-2002 "Rating of specimens and test pieces of metals and other inorganic coatings on a metal matrix after corrosion test"); the conductivity test result (International Standard for Conductive Copper) is 88.5% IACS.

[0034] Examples 2-6 and Comparative Examples 1-2

[0035] Compared with Example 1, Examples 2-6 and Comparative Examples 1-2 were performed according to the raw material ratios shown in Table 1, while the remaining steps and conditions were the same as in Example 1. The performance test results of the obtained copper alloy wires are shown in Table 1 below.

[0036] Table 1. Performance test results of copper alloy wires with different raw material ratios

[0037]

[0038] As shown in Table 1, when the amount of tungsten-copper alloy powder added does not exceed 24% (tungsten content not exceeding 12%), the tensile strength and corrosion resistance of the resulting copper alloy wires increase with the increase of tungsten-copper alloy powder addition. However, when the amount of tungsten-copper alloy powder added reaches 30% (tungsten content 15%), the tensile strength and corrosion resistance decrease significantly, indicating that structural defects in the copper alloy obtained by conventional smelting increase significantly after the tungsten content exceeds a certain proportion. Furthermore, the comparison between Examples 1 and 2 shows that the addition of tungsten-copper alloy powder can significantly improve the tensile strength and corrosion resistance of the resulting copper alloy wires, and the Ni-Co-Al medium-entropy alloy has a synergistic effect on the reinforcement of the tungsten-copper alloy.

[0039] Example 7

[0040] A method for preparing a copper alloy wire includes the following steps:

[0041] Steps (1) and (2) are the same as in Example 1;

[0042] (3) By mass percentage, 4% Ni-Co-Al medium entropy alloy, 11.4% copper-containing 30wt% tungsten copper alloy powder (80 mesh) and 84.6% copper ingots are added to a horizontal furnace for smelting at a temperature of 1500-1550℃. The molten copper is cooled by a condenser and then pulled out by a traction mechanism. It is then annealed at 600-650℃ and cooled before being wound by a rewinding machine to obtain copper alloy wire.

[0043] The copper alloy wire obtained in this embodiment has a tensile strength of 344 MPa, a corrosion resistance of level 9 in the acetic acid salt spray test (AASS) for 24 hours, and a conductivity test result (International Standard for Conductive Copper) of 87.6% IACS.

[0044] Example 8

[0045] A method for preparing a copper alloy wire includes the following steps:

[0046] Steps (1) and (2) are the same as in Example 1;

[0047] (3) By mass percentage, 4% Ni-Co-Al medium entropy alloy, 10% copper-containing 20wt% tungsten copper alloy powder (80 mesh) and 86% copper ingots are added to a horizontal furnace for smelting at a temperature of 1500-1550℃. The molten copper is cooled by a condenser and then pulled out by a traction mechanism. It is then annealed at 600-650℃ and cooled before being wound by a rewinding machine to obtain copper alloy wire.

[0048] The copper alloy wire obtained in this embodiment has a tensile strength of 321 MPa, a corrosion resistance of level 8 in the acetic acid salt spray test (AASS) for 24 hours, and a conductivity test result (International Standard for Conductive Copper) of 83.8% IACS.

[0049] The comparison between Examples 7-8 and Example 1 shows that, under the same tungsten content, the lower the copper content of the tungsten-copper alloy powder, the worse the reinforcing effect of the resulting copper alloy. When the copper content of the tungsten-copper alloy powder is below 30 wt%, the tensile strength, corrosion resistance, and electrical conductivity of the resulting copper alloy all decrease significantly. This is because the lower the copper content of the tungsten-copper alloy powder, the worse its plasticity, leading to a poorer mixing and melting effect with the copper substrate and an increase in structural defects.

[0050] Comparative Example 3

[0051] A method for preparing a copper alloy wire includes the following steps:

[0052] Steps (1) and (2) are the same as in Example 1;

[0053] (3) By mass percentage, 4% Ni-Co-Al medium entropy alloy, 8% pure copper powder (80 mesh), 8% pure tungsten powder (80 mesh) and 80% copper ingot are added to a horizontal furnace for smelting at a temperature of 1500-1550℃. The molten copper is cooled by a condenser and then pulled out by a traction mechanism. It is then annealed at 600-650℃ and cooled before being wound by a rewinding machine to obtain copper alloy wire.

[0054] The copper alloy wire obtained in this comparative example has a tensile strength of 270 MPa, a corrosion resistance of level 7 in the acetic acid salt spray test (AASS) for 24 hours, and a conductivity test result (International Standard for Conductive Copper) of 80.4% IACS.

[0055] The comparison results between this comparative example and Examples 1 and 7-8 show that the tensile strength, corrosion resistance, and conductivity of the copper alloy wires obtained by directly mixing and melting pure tungsten powder are significantly reduced. This indicates that directly mixing and melting pure tungsten powder with copper substrate yields poor results.

[0056] Comparative Example 4

[0057] A method for preparing copper alloy wires, compared with Example 1, does not pre-prepare Ni-Co-Al medium-entropy alloy micro powder, but directly uses elemental powder mixing and melting. The specific preparation steps are as follows:

[0058] (1) Mix Ni, Co and Al elemental powders with an average particle size ≤50μm and a purity >99.9% at a molar ratio of 1:1:1 to obtain a mixed powder.

[0059] (2) By mass percentage, 4% of the mixed powder, 16% of tungsten copper alloy powder (80 mesh) with a copper content of 50wt% and 80% of copper ingots are added to a horizontal furnace for smelting at a temperature of 1500-1550℃. The molten copper is cooled by a condenser and then pulled out by a traction mechanism. It is then annealed at 600-650℃ and cooled before being wound by a rewinding machine to obtain copper alloy wire.

[0060] The copper alloy wire obtained in this comparative example has a tensile strength of 309 MPa, a corrosion resistance of level 8 in the acetic acid salt spray test (AASS) for 24 hours, and a conductivity test result (International Standard for Conductive Copper) of 81.6% IACS.

[0061] The comparison results between this comparative example and Example 1 show that without prior high-energy ball milling followed by melting to prepare the Ni-Co-Al medium-entropy alloy, the compatibility of the elemental powder with tungsten and copper is reduced, resulting in a significant decrease in the reinforcing effect on the copper alloy.

[0062] Example 9

[0063] A method for preparing a copper alloy wire includes the following steps:

[0064] (1) Ni, Co and Al elemental powders with an average particle size ≤50μm and a purity >99.9% were mixed at a molar ratio of 1:1:0.95 and added to a high-energy ball mill. The mixture was ball-milled for 6 hours at a ball-to-material ratio of 8:1 and a rotation speed of 500r / min to obtain Ni-Co-Al medium-entropy alloy micro powder.

[0065] (2) The obtained Ni-Co-Al medium-entropy alloy micro powder was added to a vacuum electric arc furnace for melting. The melting temperature was 1300-1350℃ and the melting time was 120min. After melting, the alloy was cooled with the furnace to obtain Ni-Co-Al medium-entropy alloy.

[0066] (3) By mass percentage, 4% Ni-Co-Al medium entropy alloy, 16% copper-containing 50wt% tungsten copper alloy powder (80 mesh) and 80% copper ingots are added to a horizontal furnace for smelting at a temperature of 1400-1450℃. The molten copper is cooled by a condenser and then pulled out by a traction mechanism. It is then annealed at 500-550℃ and cooled before being wound by a rewinding machine to obtain copper alloy wire.

[0067] Example 10

[0068] A method for preparing a copper alloy wire includes the following steps:

[0069] (1) Ni, Co and Al elemental powders with an average particle size ≤50μm and a purity >99.9% were mixed at a molar ratio of 0.95:1:1.05 and added to a high-energy ball mill. The mixture was ball-milled for 6 hours at a ball-to-material ratio of 10:1 and a rotation speed of 500r / min to obtain Ni-Co-Al medium-entropy alloy micro powder.

[0070] (2) The obtained Ni-Co-Al medium-entropy alloy micro powder was added into the heating chamber of the discharge plasma sintering system. After evacuation, one-step liquid phase sintering was performed by discharge plasma. The sintering temperature was 1150-1200℃ and the holding time was 5min. After sintering, the Ni-Co-Al medium-entropy alloy was obtained by cooling with the furnace.

[0071] (3) By mass percentage, 4% Ni-Co-Al medium entropy alloy, 16% copper-containing 50wt% tungsten copper alloy powder (80 mesh) and 80% copper ingots are added to a horizontal furnace for smelting at a temperature of 1450-1500℃. The molten copper is cooled by a condenser and then pulled out by a traction mechanism. It is then annealed at 550-600℃ and cooled before being wound by a rewinding machine to obtain copper alloy wire.

[0072] Example 11

[0073] A method for preparing a copper alloy wire includes the following steps:

[0074] (1) Ni, Co, and Al elemental powders with an average particle size ≤50μm and a purity >99.9% were mixed in a molar ratio of 1.05:0.95:1.05 and added to a high-energy ball mill. The mixture was ball-milled for 8 hours at a ball-to-material ratio of 12:1 and a rotation speed of 400r / min to obtain Ni-Co-Al medium-entropy alloy micro powder.

[0075] (2) The obtained Ni-Co-Al medium-entropy alloy micro powder was added into the heating chamber of the discharge plasma sintering system. After evacuation, one-step liquid phase sintering was performed by discharge plasma. The sintering temperature was 1100-1150℃ and the holding time was 10min. After sintering, the Ni-Co-Al medium-entropy alloy was obtained by cooling with the furnace.

[0076] (3) By mass percentage, 4% Ni-Co-Al medium entropy alloy, 16% copper-containing 50wt% tungsten copper alloy powder (80 mesh) and 70% copper ingots are added to a horizontal furnace for smelting at a temperature of 1550-1600℃. The molten copper is cooled by a condenser and then pulled out by a traction mechanism. It is then annealed at 650-700℃ and cooled before being wound by a rewinding machine to obtain copper alloy wire.

[0077] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a copper alloy material, characterized in that, Includes the following steps: (1) Ni, Co and Al elemental powders were mixed in a molar ratio of 0.95~1.05:0.95~1.05:0.95~1.05 and then ball-milled at high energy to obtain Ni-Co-Al medium-entropy alloy micro powder; (2) The obtained Ni-Co-Al medium-entropy alloy micro powder is subjected to vacuum arc melting or discharge plasma sintering to obtain Ni-Co-Al medium-entropy alloy; (3) The Ni-Co-Al medium-entropy alloy is mixed and smelted with tungsten copper alloy and copper ingot to obtain copper alloy material.

2. The method for preparing a copper alloy material according to claim 1, characterized in that, The average particle size of the Ni, Co, and Al elemental powders mentioned in step (1) is ≤50μm, and the purity is >99.9%; the high-energy ball milling refers to ball milling for 4 to 12 hours under the conditions of a ball-to-material ratio of 8 to 15:1 and a rotation speed of 300 to 500 r / min.

3. The method for preparing a copper alloy material according to claim 1, characterized in that, The temperature of vacuum arc melting in step (2) is 1200-1400℃; the temperature of discharge plasma sintering is 1100-1200℃.

4. The method for preparing a copper alloy material according to claim 1, characterized in that, The mass percentage ratio of the Ni-Co-Al medium-entropy alloy, tungsten-copper alloy and copper ingots mixed and smelted in step (3) is: 2% to 5% for Ni-Co-Al medium-entropy alloy, 5% to 25% for tungsten-copper alloy and 70% to 93% for copper ingots.

5. The method for preparing a copper alloy material according to claim 4, characterized in that, The tungsten-copper alloy uses tungsten-copper alloy powder with a copper content of ≥30% by mass and a particle size of 0.1-0.2 mm.

6. The method for preparing a copper alloy material according to claim 5, characterized in that, The tungsten content in the copper alloy material is controlled to be 3% to 12% by mass.

7. The method for preparing a copper alloy material according to claim 1, characterized in that, The mixing and melting described in step (3) is completed in a melting furnace at a temperature of 1400 to 1600°C.

8. The method for preparing a copper alloy material according to claim 1, characterized in that, After melting as described in step (3), the material is further annealed at a temperature of 500–700°C.

9. A copper alloy material, characterized in that, It is prepared by the method described in any one of claims 1 to 8.

10. A copper conductor made using the copper alloy material of claim 9.

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