High-strength and high-conductivity Cu-Fe alloy wire and preparation method thereof

Abstract

This invention discloses a high-strength, high-conductivity Cu-Fe alloy wire and its preparation method. The method involves continuous drawing deformation and intermediate annealing to prepare Cu-Fe alloy wire. The process includes cold drawing deformation at room temperature, followed by annealing at 400–550°C after the drawing strain reaches 2–2.5. Drawing deformation is then continued until the cumulative drawing strain of the alloy wire reaches 1–1.2, at which point it is annealed again at 400–550°C. This process is repeated until Cu-Fe alloy wire of the target size is obtained. Compared with metal wires prepared by traditional methods, the Cu-Fe alloy wire prepared by this invention has higher strength and conductivity. The production equipment and process are simple, resulting in low cost, high controllability, and ease of industrial production.

Description

Technical Field

[0001] This invention relates to a high-strength, high-conductivity Cu-Fe alloy wire and its preparation method, belonging to the technical field of high-strength, high-conductivity copper alloys. Background Technology

[0002] Cu-Fe alloys with high Fe content possess advantages such as high electrical and thermal conductivity, strength, hardness, and magnetic properties, as well as abundant raw materials and low cost, and are expected to be used as high-strength and high-conductivity electromagnetic shielding materials.

[0003] Currently, Cu-Fe alloy materials prepared by conventional methods suffer from problems such as uneven microstructure, low strength, and low electrical conductivity, which limit their large-scale industrial development.

[0004] Large plasticity cold drawing deformation can significantly improve the strength of alloys and improve the inhomogeneity of the microstructure; however, the increase in strength is often accompanied by a decrease in electrical conductivity, and without annealing heat treatment, Cu-Fe alloys will break after the cumulative drawing strain reaches only about 4.5.

[0005] Therefore, in order to solve the above problems and better promote the industrial production and application of Cu-Fe alloys, a preparation method combining continuous cold drawing deformation and intermediate heat treatment is invented to obtain Cu-Fe alloy wires with high strength and high conductivity, which has important economic and social significance. Summary of the Invention

[0006] Objective of the invention: In view of the shortcomings of the prior art, the first objective of the present invention is to provide a high-strength and high-conductivity Cu-Fe alloy wire, and the second objective of the present invention is to provide a method for preparing the high-strength and high-conductivity Cu-Fe alloy wire.

[0007] Technical solution: The present invention discloses a method for preparing high-strength, high-conductivity Cu-Fe alloy wire, characterized by comprising the following steps:

[0008] (1) Pretreatment: The Cu-Fe alloy rod is drawn at room temperature and then annealed after the drawing strain reaches 2 to 2.5 to obtain the pretreated Cu-Fe alloy wire.

[0009] (2) Intermediate annealing: The pretreated Cu-Fe alloy wire is further cold-drawn at room temperature. When the cumulative drawing strain reaches 1 to 1.2, annealing is performed.

[0010] (3) Post-processing: Repeat step (2) multiple times on the Cu-Fe alloy wire after annealing in step (2) until the high-strength and high-conductivity Cu-Fe alloy wire is prepared.

[0011] Furthermore, in steps (1) to (3), the annealing process is carried out at 400℃ to 550℃ for 30 min to 4 h.

[0012] Furthermore, the Fe content in the Cu-Fe alloy rod is 5-95 wt%, with the balance being Cu.

[0013] Furthermore, the Cu-Fe alloy rod also contains trace amounts of metallic elements, trace amounts of non-metallic elements, and / or trace amounts of rare earth elements.

[0014] Furthermore, the metallic element is Mg and / or Zr, the non-metallic element is Si, and the rare earth element is one or more of Ce, La, Nd, or Y.

[0015] Furthermore, the Cu-Fe alloy rod contains 0.1–3 wt% Si, 0.2–0.6 wt% Mg, 0.2–0.8 wt% Zr, and 0.002–0.1 wt% rare earth elements.

[0016] Furthermore, in step (1), the Cu-Fe alloy rod is made by induction melting, electric arc melting or electric arc additive manufacturing of Cu and Fe alloy raw materials to form Cu-Fe alloy ingots, and then hot forging at high temperature.

[0017] Furthermore, high-temperature hot forging involves holding a Cu-Fe alloy ingot in a vacuum at 500–550°C for 30 min–4 h, air-cooling it, and then hot-forging it at 900–1000°C.

[0018] Furthermore, an Fe-Si anti-oxidation coating is applied to the surface of the Cu-Fe alloy ingot before vacuum insulation.

[0019] Furthermore, after grinding, cleaning, and drying, the bulk Cu and Fe alloy blocks are weighed according to the designed weight percentage, and then melted into Cu-Fe alloy ingots using vacuum arc melting, vacuum induction melting, or arc additive manufacturing.

[0020] The high-strength, high-conductivity Cu-Fe alloy wire obtained by the preparation method described in this invention.

[0021] The Cu-Fe alloy wire prepared by this invention has the Fe phase existing in the form of continuous Fe fibers in the Cu matrix, effectively avoiding the additional scattering of electrons caused by the increase in the specific surface area of ​​the phase interface due to the fragmentation of Fe fibers during continuous drawing deformation. Intermediate annealing treatment promotes the precipitation of dissolved Fe elements in the Cu matrix, resulting in a steady increase in conductivity; on the other hand, it softens the fibrous Fe phase, which is beneficial for further cold drawing deformation without causing wire breakage. The intermediate annealing strain in this invention is controlled at 1-1.2. When the drawing strain is too large, the Fe fibers will break and dissolve, leading to a decrease in conductivity, and the breakage of Fe fibers is irreversible.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0023] (1) The best mechanical properties of the Cu-Fe alloy wire prepared by the present invention at room temperature are: hardness 197HV, tensile yield strength 1100MPa, and elongation at break close to 2%, which are far superior to similar alloys; the electrical conductivity is maintained at 56%IACS, which is higher than that of Cu-Fe alloy wires obtained by casting and pure drawing.

[0024] (2) The present invention eliminates the coarse dendrite structure and dendrite segregation in the cast Cu-Fe alloy, and the microstructure of the prepared Cu-Fe alloy wire is a fibrous nano-Fe sheet structure.

[0025] (3) The present invention uses a hot forging, room temperature cold drawing and intermediate annealing heat treatment process to prepare Cu-Fe alloy wire, which broadens the application range of Cu-Fe alloy. The preparation process of the present invention is simple, feasible and effective, so Cu alloy wire has good application prospects. Attached Figure Description

[0026] Figure 1 The tensile stress-strain curves of the Cu-Fe alloy wire prepared in Example 1 under different drawing strains are shown.

[0027] Figure 2 This is a graph showing the hardness variation of the Cu-Fe alloy wire prepared in Example 1 under different drawing strains;

[0028] Figure 3 The graph shows the change in conductivity of the Cu-Fe alloy wire prepared in Example 1 under different drawing strains.

[0029] Figure 4 Microstructure diagrams of the Cu-Fe alloy wire prepared in Example 1 under different states;

[0030] Figure 5 This is the process route diagram for Comparative Example 1. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0032] The materials used in the following examples are all commercially available.

[0033] Example 1

[0034] 1. Preparation of Cu-Fe alloy ingots: The bulk Cu and Fe alloy blocks are weighed according to the weight percentages of Cu 80% and Fe 20%, and the bulk Cu and Fe alloy blocks are melted into Cu-Fe alloy ingots using vacuum induction melting technology.

[0035] 2: Heat treatment of Cu-Fe alloy ingots: Apply Fe-Si anti-oxidation coating to the surface of Cu-Fe alloy ingots, keep them at 500℃ for 4 hours in a vacuum resistance box, and then air cool them.

[0036] 3. Preparation of Cu-Fe alloy rods: After heat treatment, Cu-Fe alloy ingots are placed in a resistance furnace at 1000℃ and held for 1 minute. The alloy is then hot-forged into rods with a diameter of 14mm using a forging machine, and then machined to a diameter of 12mm to obtain Cu-Fe alloy rods.

[0037] 4. Pretreatment: At room temperature, Cu-Fe alloy bars are drawn sequentially to 4.5 mm in one pass, with a drawing strain of about 2, to obtain pretreated Cu-Fe alloy wire.

[0038] 5. Intermediate annealing: The pretreated Cu-Fe alloy wire was drawn to 2.7 mm at room temperature with a drawing strain of 1.02; then annealed at 500℃ for 1 h.

[0039] 6. Post-processing: Repeat step 5 above 5 times to finally obtain a Cu-Fe alloy wire with a diameter of 270 micrometers.

[0040] Stress-strain tensile properties were tested on samples from different passes during the preparation of the Cu-Fe alloy wire in this embodiment. The results are as follows: Figure 1 As shown. Figure 1 The image shows the tensile stress-strain curves of the Cu-Fe alloy wire prepared in Example 1 under different drawing strains. D represents the drawing deformation, A represents the annealing process after deformation, and the numbers represent the drawing strain of the Cu-Fe alloy wire. The calculation formula is: Strain = 2ln(D0 / Di), where D0 represents the initial diameter of 12 mm, and Di represents the diameter of the test wire. Figure 1 It can be seen that with continuous drawing deformation and intermediate annealing treatment, the tensile strength of Cu-Fe alloy wire continues to increase, until the strain exceeds 1100MPa.

[0041] Stress-strain-hardness properties of samples from different passes during the preparation of the Cu-Fe alloy wire in this embodiment were tested, and the results are as follows: Figure 2 As shown. Figure 2 This is a graph showing the hardness variation of the Cu-Fe alloy wire prepared in Example 1 under different drawing strains; where AJ represents the letters of the alphabet. Figure 1 Corresponding to the Chinese text. (By) Figure 2 It is evident that the hardness of Cu-Fe alloy wire continuously increases with continuous drawing deformation and intermediate annealing treatment.

[0042] Conductivity tests were performed on samples from different passes during the preparation of the Cu-Fe alloy wire in this embodiment. The results are as follows: Figure 3 As shown. Figure 3 The graph shows the conductivity variation of the Cu-Fe alloy wire prepared in Example 1 under different drawing strains; from Figure 3 visible, Figure 3 The conductivity test results show that the conductivity of Cu-Fe alloy wire continues to increase with continuous drawing deformation and intermediate annealing treatment.

[0043] Scanning electron microscopy (SEM) tests were performed on samples from different passes during the preparation of the Cu-Fe alloy wire in this embodiment. The results are as follows: Figure 4 As shown. Figure 4 These are microstructure images of the Cu-Fe alloy wire prepared in Example 1 under different states, where the letters A and J represent the... Figure 1 Corresponding to the Chinese text. (By) Figure 4 visible, Figure 4 The microstructure of Cu-Fe alloy wires with different drawing strains was determined, and the Fe phase eventually transformed into a nano-Fe fiber morphology.

[0044] The Cu-Fe alloy wire obtained in this embodiment was subjected to mechanical and electrical property tests. Its optimal hardness was 197 HV, elongation at break was 1.8%, tensile strength was 1100 MPa, and electrical conductivity was 56% IACS.

[0045] Example 2

[0046] 1. Preparation of Cu-Fe alloy ingots: The bulk Cu, bulk Fe, and Fe-3Si alloy blocks were weighed according to the weight percentages of 10% Fe, 0.5% Si, and the remainder Cu. The bulk Cu, Fe-Si, and Fe alloy blocks were melted into 2kg Cu-Fe alloy ingots using vacuum induction melting technology.

[0047] 2. Heat treatment of Cu-Fe alloy ingots: Apply Fe-Si anti-oxidation coating to the surface of Cu-Fe alloy ingots, keep them at 500℃ for 4 hours in a vacuum resistance box, and then air cool them.

[0048] 3. Preparation of Cu-Fe alloy rods: After heat treatment, Cu-Fe alloy ingots are placed in a resistance furnace at 1000℃ and held for 1 minute. The alloy is then hot-forged into rods with a diameter of 13mm using a forging machine, and then machined to a diameter of 12mm to obtain Cu-Fe alloy rods.

[0049] 4. Pretreatment: At room temperature, Cu-Fe alloy bars are drawn sequentially to 3.5 mm in one pass, with a drawing strain of about 2.5, to obtain pretreated Cu-Fe alloy wire.

[0050] 5. Intermediate annealing: The pretreated Cu-Fe alloy wire was drawn to 2 mm at room temperature with a drawing strain of 1.12; then annealed at 550℃ for 30 min.

[0051] 6. Post-processing: Repeat step 5 above 5 times to finally obtain a Cu-Fe alloy wire with a diameter of 220 micrometers.

[0052] The Cu-Fe alloy wire obtained in this embodiment underwent mechanical and electrical tests, and its hardness was 195 HV, elongation at break was 1.5%, tensile strength was 1050 MPa, and electrical conductivity was 65% IACS.

[0053] Example 3

[0054] 1. Preparation of Cu-Fe alloy ingots: Bulk Cu, bulk Fe, and Cu-1%La alloy bulks are weighed according to the weight percentages of 0.05%La, 15%Fe, and the remainder Cu. The Cu-1%La alloy bulks are then melted with bulk Cu and bulk Fe using vacuum induction melting technology to form Cu-Fe alloy ingots.

[0055] 2. Heat treatment of Cu-Fe alloy ingots: Apply Fe-Si anti-oxidation coating to the surface of Cu-Fe alloy ingots, keep them at 500℃ for 4 hours in a vacuum resistance box, and then air cool them.

[0056] 3. Preparation of Cu-Fe alloy bars: The heat-treated Cu-Fe alloy ingot was placed in a 1000℃ resistance furnace and held for 1 minute. The alloy was then hot-forged into bars with a diameter of 14mm using a forging machine, and finally machined to a diameter of 12mm to obtain Cu-Fe alloy bars.

[0057] 4. Pretreatment: At room temperature, Cu-Fe alloy bars are drawn sequentially to 4.5 mm in one pass, with a drawing strain of about 2, to obtain pretreated Cu-Fe alloy wire.

[0058] 5. Intermediate annealing: The pretreated Cu-Fe alloy wire was drawn to 2.7 mm at room temperature with a drawing strain of 1.02; then annealed at 400℃ for 4 h.

[0059] 6. Post-processing: Repeat step 5 above multiple times to finally obtain a Cu-Fe alloy wire with a diameter of 250 micrometers.

[0060] The mechanical and electrical properties of the Cu-Fe alloy wire obtained in this embodiment were analyzed. Its hardness was 190 HV, elongation at break was 1.6%, tensile strength was 1000 MPa, and electrical conductivity was 62% IACS.

[0061] Example 4

[0062] The experimental procedure was the same as in Example 1, except that the pretreatment drawing strain was 1.8 and 3.0, respectively. The resulting Cu-Fe alloy wires had hardnesses of 170 HV and 175 HV, elongation at break of 1% and 1.5%, tensile yield strengths of 700 MPa and 720 MPa, and electrical conductivity of 43% IACS and 48 IACS, respectively.

[0063] Example 5

[0064] The experimental procedure was the same as in Example 1, except that the intermediate annealing was performed with drawing strains of 0.5 and 1.5, respectively. The resulting Cu-Fe alloy wires had hardnesses of 180 HV and 192 HV, elongation at break of 3% and 1.8%, tensile yield strengths of 850 MPa and 930 MPa, and electrical conductivity of 53% IACS and 50% IACS, respectively.

[0065] Comparative Example 1

[0066] The Cu-Fe alloy wire prepared in Example 1 of this invention was compared with Cu-14Fe alloy wire prepared by Zou et al. (Vacuum 167 (2019) 54–58) at Jiangxi Copper & Tungsten New Materials Laboratory using cold drawing deformation and intermediate annealing. Zou et al. used an initial drawing strain of 3.7 and an intermediate interval drawing strain of 2. Under the premise of the same total drawing strain, its process route is as follows: Figure 5 As shown, the highest performance obtained was a strength of 830 MPa and an electrical conductivity of 53% IACS, which is far lower than the comprehensive performance of the Cu-Fe alloy wire obtained in Example 1 of this invention, which was 1050 MPa / 56% IACS.

[0067] Comparative Example 2

[0068] The Cu-Fe alloy wire prepared in Example 1 of this invention was compared with Cu-14Fe-0.1Ag prepared by Liu et al. of Nanchang Institute of Technology (Materials Science & Engineering A673 (2016) 1–7). Liu et al. cold-drawn Cu-14Fe-0.1Ag to a strain of 7.8 and then heat-treated it. Their results showed that even with the addition of 0.1wt% Ag, the best performance obtained was only a strength of 1000MPa and an electrical conductivity of 56% IACS. Compared with the Cu-Fe alloy wire material prepared in Example 1 of this invention, not only is the raw material cost higher, but the performance is also lower. The results indicate that the intermediate heat treatment of this invention has a higher performance advantage than continuous drawing deformation followed by heat treatment, achieving very good technical results.

Claims

1. A method for preparing a high-strength, high-conductivity Cu-Fe alloy wire, characterized in that, Includes the following steps: (1) Pretreatment: The Cu-Fe alloy rod is drawn at room temperature and annealed after the drawing strain reaches 2~2.5 to obtain the pretreated Cu-Fe alloy wire. (2) Intermediate annealing: The pretreated Cu-Fe alloy wire is cold-drawn at room temperature. When the cumulative drawing strain reaches 1~1.2, annealing is performed. (3) Post-processing: Repeat step (2) multiple times on the Cu-Fe alloy wire after annealing in step (2) until the high-strength and high-conductivity Cu-Fe alloy wire is prepared.

2. The preparation method according to claim 1, characterized in that, In steps (1) to (3), the annealing process is carried out at 400~550℃ for 30min~4h.

3. The preparation method according to claim 1, characterized in that, The Cu-Fe alloy rod contains 5-20 wt% Fe and the balance is Cu.

4. The preparation method according to claim 3, characterized in that, The Cu-Fe alloy rod also contains trace amounts of metallic elements, trace amounts of non-metallic elements, and / or trace amounts of rare earth elements.

5. The preparation method according to claim 4, characterized in that, The metallic element is Mg and / or Zr, the non-metallic element is Si, and the rare earth element is one or more of Ce, La, Nd, or Y.

6. The preparation method according to claim 5, characterized in that, The Cu-Fe alloy rod contains 0.1-3 wt% Si, 0.2-0.6 wt% Mg, 0.2-0.8 wt% Zr, and 0.002-0.1 wt% rare earth elements.

7. The preparation method according to any one of claims 1-6, characterized in that, In step (1), the Cu-Fe alloy rod is made by induction melting, electric arc melting or electric arc additive manufacturing of Cu and Fe alloy raw materials to form Cu-Fe alloy ingots, and then hot forging at high temperature.

8. The preparation method according to claim 7, characterized in that, High-temperature hot forging involves holding a Cu-Fe alloy ingot in a vacuum at 500~550°C for 30 min~4 h, air cooling it, and then hot forging it at 900~1000°C.

9. The preparation method according to claim 8, characterized in that, Before vacuum heat preservation, apply an Fe-Si anti-oxidation coating to the surface of the Cu-Fe alloy ingot.

10. The high-strength, high-conductivity Cu-Fe alloy wire obtained by the preparation method according to any one of claims 1-9.

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