A high-strength high-conductivity copper alloy material, a preparation method and application thereof

Abstract

The application discloses a high-strength and high-conductivity copper alloy material and a preparation method and application thereof, and the high-strength and high-conductivity copper alloy material comprises, in mass fraction, Ni: 4.8-5.5 wt%, Co: 0.05-0.1 wt%, Si: 1.17-1.34 wt%, Cr: 0.1-0.3 wt%, and the balance is copper and inevitable impurities. The preparation method of the copper alloy comprises the following steps: batching, up-drawing continuous casting, cold rolling, primary aging treatment, cold drawing and secondary aging treatment. The application improves the nickel and silicon contents in the copper alloy, utilizes multi-stage cold processing and multi-stage aging treatment, controls the size, quantity and morphology of discontinuous precipitated phases and continuous precipitated phases in the copper alloy, simultaneously utilizes the promoting effect of Co and Cr elements on the secondary phase and the hindering effect on dislocations, and cooperatively improves the performance of the copper alloy. The copper alloy material prepared by the application has high strength and high conductivity, and has wide application prospects in the fields of electronic appliances, aerospace, instruments and meters and the like.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical materials, specifically relating to a high-strength, high-conductivity copper alloy material, its preparation method, and its application. Background Technology

[0002] Beryllium copper alloys are widely used in high-end fields due to their high strength, high elasticity, high conductivity, and good corrosion resistance. However, the use of beryllium is limited because beryllium is volatile during the smelting process and can cause harm to the human body, and beryllium is also expensive. Copper-nickel-silicon alloys, on the other hand, offer similar strength, elasticity, conductivity, and corrosion resistance compared to beryllium copper, making them the most promising alternative to beryllium copper, especially in applications requiring high conductivity.

[0003] However, current copper-nickel-silicon products still lag behind beryllium copper in their ability to replace it, primarily because they cannot guarantee both high strength and high conductivity. Patent document CN115627379B discloses a copper alloy rod with the following mass percentage composition: Ni: 4.0–6.8 wt%, Si: 0.86–1.5 wt%, Mn: 0.12–0.60%, B: 0.001–0.06 wt%, with the balance being Cu and unavoidable impurities. This invention, by adding Mn and B elements to copper-nickel-silicon, controls the distribution of NiSi and MnSi phases in the matrix and the dislocation density in the alloy. Although the tensile strength of the alloy is >1100 MPa, the conductivity is significantly reduced, not exceeding 28% IACS.

[0004] Patent document CN117051285B discloses a copper-nickel-silicon alloy, comprising, by weight percentage: Ni: 2.0–4.0%, Si: 0.3–1.0%, Sn: 0.1–1.0%, Mg: 0.05–0.5%, P: 0.1–0.3%, Cr: 0.05–0.5%, Nb: 0.1–0.7%, RE: 0.05–0.3%, where RE is La or Ce, and the balance is copper. This invention uses Nb instead of Co, and adds other elements such as Si, Cr, and P to form precipitates that hinder dislocation movement. The resulting alloy has a conductivity ≥43% IACS. However, its tensile strength is only 700-800 MPa, making it unsuitable as a substitute for beryllium copper in high-strength, high-conductivity applications.

[0005] Patent document CN106399749B discloses a high-strength, high-elasticity copper-nickel-silicon alloy material. The weight percentage composition of the material is as follows: Ni: 0.5-3.0%, Co: 0.3-3.0%, Si: 0.25-1.5%, Mg: 0.01-0.05%, B: 0.002-0.005%, mixed rare earth (Sc:Y:La = 1:3:5) 0.02-0.05%, wherein the mass ratio of nickel to cobalt is 0.5-6.0, and the remainder is Cu. It also includes at least one or two of the four elements Cr, Ti, Ag, and Zr. The total content of alloying elements is 0.02-0.5%. The alloy material is prepared by smelting and casting, hot rolling, milling, rough rolling, intermediate annealing, intermediate rolling, high-temperature rapid solution treatment, finish rolling, and aging treatment. Although the conductivity of this alloy material can reach 40-50% IACS, its tensile strength is only 800-950 MPa, which still cannot meet the requirements of high strength and high conductivity materials.

[0006] In summary, to address the shortcomings of existing technologies, it is necessary to develop a copper-nickel-silicon alloy that possesses both high strength and high conductivity for use in high-strength and high-conductivity applications. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides a high-strength, high-conductivity copper alloy material. This copper alloy material has both high strength and high conductivity, and can replace some beryllium copper in high-strength, high-conductivity industries.

[0008] A high-strength, high-conductivity copper alloy material, by mass fraction, comprises Ni: 4.8–5.5 wt%, Co: 0.05–0.1 wt%, Si: 1.17–1.34 wt%, Cr: 0.1–0.3 wt%, with the balance being copper and unavoidable impurities.

[0009] Preferably, the secondary strengthening phase of the high-strength, high-conductivity copper alloy material comprises discontinuous precipitates and continuous precipitates, wherein the ratio of the discontinuous precipitates to the continuous precipitates is 1:5 to 10, and wherein the continuous precipitates are granular with a particle size ≤4μm and a quantity >30,000 per square millimeter. 2 The discontinuous precipitates are in the form of nanofibers with a thickness of ≤10μm.

[0010] Nickel: Nickel can be dissolved in copper alloys indefinitely, but relying solely on Ni solid solution strengthening to improve the strength of materials is often ineffective. Therefore, adding a certain amount of silicon to the alloy and forming a dispersed Ni2Si phase through age strengthening can greatly improve the strength of the material.

[0011] Although nickel and silicon can form a dispersed Ni2Si phase through aging strengthening, thereby improving the material strength, and the material strength increases with the increase of nickel and silicon content, the solid solubility of Ni2Si in the copper matrix is ​​limited. As the nickel and silicon content further increases, the nickel and silicon cannot be completely dissolved into the copper matrix, but will exist in the grain boundary in the form of eutectic. Once the eutectic phase forms a network structure at the grain boundary, it will greatly deteriorate the material properties. Therefore, this invention appropriately increases the Ni and Si content based on the maximum solid solubility.

[0012] Preferably, the mass ratio of nickel to silicon in the high-strength, high-conductivity copper alloy material is 4 to 4.3:1. By controlling the mass ratio of nickel to silicon within the above range, the present invention can better form a dispersed Ni2Si phase and improve the strength of the alloy.

[0013] Cobalt: Cobalt reduces the conductivity of copper alloys. Adding too much cobalt will severely reduce the conductivity of copper alloys. However, appropriate amounts of cobalt are beneficial to the alloy properties. This is mainly because the reaction of Co with silicon can generate fine Co2Si phases, which preferentially form at vacancy defects. The formation of Co2Si phase can promote the nucleation of Ni2Si phase, while the occupancy of vacancies by Co2Si phase can inhibit the growth of Ni2Si phase during the aging process to a certain extent.

[0014] Chromium: Chromium has a relatively small effect on the conductivity of copper alloys. During the aging process, Cr can precipitate in the elemental state, providing nucleation sites for the subsequent precipitation of continuous phases, thereby increasing the dispersion of the continuous secondary phases. Cr can also react with silicon to form the CrSi phase, thereby precipitating Si elements as much as possible, reducing the influence of residual silicon elements in the copper matrix on conductivity, and giving the alloy a high conductivity.

[0015] Preferably, the high-strength, high-conductivity copper alloy material has a strength >1050 MPa and a conductivity ≥43% IACS. The copper alloy material of this invention possesses both high strength and high conductivity, meeting the material requirements in the field of high-strength, high-conductivity applications.

[0016] Preferably, the grain size of the high-strength, high-conductivity copper alloy material is 15–50 μm.

[0017] The present invention also provides a method for preparing the high-strength and high-conductivity copper alloy material. Based on the improved alloy composition, the method uses multi-stage cold working and heat treatment to control the generation of discontinuous and continuous precipitates in the matrix, thereby preparing the high-strength and high-conductivity copper alloy material.

[0018] A method for preparing a high-strength, high-conductivity copper alloy material includes the following steps: batching, continuous casting; cold rolling; primary aging treatment; cold drawing; and secondary aging treatment.

[0019] The aforementioned upward continuous casting process is as follows: an upward furnace is used for melting and billet preparation, the melting and holding temperature is controlled at 1200-1250℃, the traction speed is controlled at 0.5-0.8mm / s, and argon gas protection is used during the traction process to avoid oxidation loss of alloying elements.

[0020] Specifically, before smelting, copper-chromium, copper-cobalt, and copper-silicon intermediate alloys need to be wrapped in copper foil to prepare cored wires. After smelting begins, an appropriate amount of oxygen-free copper rods are first added to the upward drawing furnace. Argon gas is introduced and the furnace is heated until the oxygen-free rods are completely melted. Then, the oxygen-free rods, nickel rods, and copper alloy cored wires are automatically fed, with the feeding rate controlled at 220 kg / h. Automatic feeding stops when the copper liquid is 20 cm from the edge of the crucible. The final temperature is maintained at 1200–1250℃. After holding at this temperature for 10–20 minutes, the composition is measured and adjusted. Once the composition is qualified, the upward drawing blank is produced. During the subsequent drawing process, the oxygen-free copper rods, cored wires (copper-chromium, copper-cobalt, and copper-silicon cored wires prepared by mixing them in a certain proportion), and nickel rods are automatically fed according to the predetermined design composition. The composition of the furnace liquid is tested every 30 minutes to ensure the composition of the upward drawing blank, and finally, the required upward drawing blank is obtained.

[0021] The cold rolling process is as follows: the prepared upward drawing blank is rolled by a cold rolling mill, the rolling is carried out continuously with multiple rolls, the rolling speed is controlled at 2-5 mm / s, and the rolling amount is controlled at 70-80%.

[0022] The process of the first-level aging treatment is as follows: the cold-rolled billet is subjected to high-temperature aging treatment, the aging temperature is controlled at 730-780℃, the holding time is controlled at 30-60min, and water cooling is used after the holding time is completed, with the converter water immersion time being less than 30s.

[0023] The cold drawing process is as follows: cold drawing is performed on the first-stage aging blank, the single-pass drawing amount is controlled at 20-25%, and the total cold drawing amount is controlled at 60-75%.

[0024] The process of the secondary aging treatment is as follows: the cold-drawn blank is subjected to low-temperature aging, the aging temperature is controlled at 420-450℃, the holding time is controlled at 4-7h, and the cooling is furnace cooling.

[0025] This invention improves the tensile strength of a material by increasing the solute content and combining multi-stage cold working and multi-stage heat treatment to control the size, morphology, and quantity of discontinuous and continuous precipitates in the matrix. This achieves a balance between the high tensile strength of the discontinuous precipitates and the hindering effect of the fine continuous precipitates on dislocations, thereby increasing the tensile strength of the material. Furthermore, the fibrous distribution of the discontinuous precipitates along the processing direction during subsequent processing reduces the hindering effect on electron conduction, thus producing a copper alloy material with high strength and high conductivity.

[0026] This invention achieves maximum solid solubility by appropriately increasing the Ni and Si content based on the maximum solid solubility, and then preparing a blank using the upward extraction method. Excess Ni and Si are dispersed as eutectic phases at the grain boundaries, avoiding the formation of a network eutectic and ensuring subsequent plastic deformation of the material. The upward extraction method directly prepares the blank, avoiding the reduction in solid solubility caused by extrusion temperature limitations during ingot extrusion, which leads to the precipitation of excess solute in large particles and weakens the strengthening effect. The upward extraction blank exhibits the greatest solid solubility effect on Ni₂Si, reaching approximately 5.6%, and a certain amount of dispersed Ni₂Si eutectic phase exists at the grain boundaries of the blank.

[0027] Because the grain size of the upward-drawing blank is relatively large, it cannot exert the fine-grain strengthening effect of the material. Therefore, the blank is cold-deformed by cold rolling. The large deformation amount is beneficial to provide driving force for subsequent recrystallization, and the large processing amount is conducive to the formation of shear bands in the material. Shear bands are conducive to increasing the nucleation of discontinuous precipitates. Although the rolling process can apply a certain compressive stress to the material, excessive processing rate can also easily lead to material cracking, especially under the condition of eutectic phase. Therefore, the cold rolling processing amount needs to be controlled at 70-80%. This processing amount can ensure the driving force for subsequent recrystallization and the formation of discontinuous precipitates, and avoid material cracking.

[0028] Since discontinuous precipitates nucleate through shear bands and grain boundaries, and their growth is mainly achieved through the diffusion of nickel and silicon within the grain boundaries, the primary aging temperature should not be too high or too low. Excessive temperature can lead to overly large discontinuous precipitates, reducing the deformation compatibility between subsequent discontinuous precipitates and the matrix. It also significantly depletes the nickel and silicon content in the copper matrix, resulting in a decrease in the number of subsequent continuous precipitates and thus weakening the synergistic strengthening effect. Conversely, excessively low temperatures result in slow nucleation rates of discontinuous precipitates, leading to insufficient numbers and reduced synergistic strengthening. Therefore, the primary aging temperature should be controlled between 730 and 780℃.

[0029] Preferably, the initial discontinuous precipitate formed during the first-stage aging process is lamellar with a thickness of ≤10μm. The initial discontinuous precipitate is coherent with the matrix and can deform in coordination with the matrix during subsequent cold drawing. As the deformation progresses, it exhibits a semi-coherent and incoherent relationship with the matrix.

[0030] Because shorter spacing between the second phases of a material results in stronger resistance to dislocations, further cold drawing is necessary. This reduces the spacing between the lamellar discontinuous precipitates and, simultaneously, provides more nucleation sites for subsequent continuous precipitates, increasing the number of secondary phases and reducing the spacing between them. Secondly, high processing volume causes the discontinuous precipitates to distribute in a fibrous pattern along the drawing direction. This distribution pattern effectively avoids hindering electron transport, ensuring high conductivity even with high nickel-silicon content. Although the discontinuous precipitates have a certain degree of compatibility with the matrix, this compatibility decreases with processing. Therefore, the subsequent processing volume needs to be controlled at 60-75% to ensure the material retains a certain degree of plasticity.

[0031] The final secondary aging process employs low-temperature annealing, causing the remaining nickel and silicon dissolved in the matrix to precipitate as discontinuous phases. Due to the large amount of subsequent processing, a high number of nuclei are provided, resulting in a continuous precipitate count exceeding 30,000 per mm. 2 This greatly enhances the resistance to dislocations and improves the material strength. Because the strength of the discontinuous Ni2Si phase is much greater than that of the matrix, the material strength is ultimately >1050 MPa and the conductivity is ≥43% IACS due to the strengthening effects of the discontinuous and continuous precipitates and the fine grain.

[0032] This invention also provides applications of the high-strength, high-conductivity copper alloy material in the fields of electronics, aerospace, and instrumentation. The copper alloy material of this invention possesses both high strength and high conductivity, with a strength exceeding 1050 MPa and a conductivity exceeding 43% IACS, making it suitable for a wide range of applications in electronics, aerospace, and other fields.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] This invention, by appropriately increasing the nickel-silicon content in copper alloys and utilizing multi-stage cold working and multi-stage aging treatments, controls the size, quantity, and morphology of discontinuous and continuous precipitates in the alloy product. Simultaneously, it leverages the promoting effect of Co and Cr elements on secondary phases and their hindering effect on dislocations to synergistically improve the properties of the copper alloy. The copper alloy material prepared by this invention possesses both high strength and high conductivity, and can replace some beryllium copper in industries such as electronics, aerospace, and instrumentation. Attached Figure Description

[0035] Figure 1 The dimensions of the continuous and discontinuous precipitates in the copper alloy prepared in Example 1 are shown.

[0036] Figure 2 The images show the morphology of the continuous and discontinuous precipitates in the copper alloy prepared in Example 2. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0038] This invention provides 3 embodiments and 4 comparative examples. The specific composition of the copper alloy in the embodiments and comparative examples is shown in Table 1.

[0039] The embodiment uses the preparation method of the present invention, and the process flow is as follows: raw material preparation → upward continuous casting → first cold working (cold rolling) → first high-temperature aging (first-level aging treatment) → water-cooled solution treatment → second cold working (cold drawing) → second low-temperature aging of finished product (second-level aging treatment). The raw materials are: oxygen-free rod, nickel rod and copper alloy core, wherein the copper-silicon cored wire is prepared by wrapping copper and silicon with T2 copper.

[0040] Example 1

[0041] The copper alloy material in this embodiment, by mass percentage, comprises: Ni: 4.8 wt%; Co: 0.05 wt%; Si: 1.17 wt%; Cr: 0.1 wt%, wherein Ni:Si = 4.1:1, and the balance is Cu. The specific preparation method of the copper alloy material in this embodiment is as follows:

[0042] Step 1: Melting and blank preparation are carried out using an upward-drawing furnace. The melting and holding temperature is controlled at 1200-1250℃, the traction speed is controlled at 0.7mm / s, argon gas protection is used during the traction process, and the cooling water flow rate is controlled at 12m³ / s. 3 The cooling water temperature is controlled at 20-25℃, and a qualified upper drawing blank is finally prepared.

[0043] Step 2: The above-mentioned upward-drawing blank is rolled using a cold rolling mill. The rolling is carried out continuously using multiple rolls, with the rolling speed controlled at 5 mm / s and the rolling amount controlled at 70%.

[0044] Step 3: Perform high-temperature aging treatment on the cold-rolled billet, with the aging temperature controlled at 730℃ and the holding time controlled at 45min. After the holding time is completed, water cooling is used, and the water immersion time in the converter is less than 30s.

[0045] Step 4: Perform cold drawing on the aged blank, with the single drawing amount controlled at 20-25% and the total cold drawing amount controlled at 60%.

[0046] Step 5: Perform low-temperature aging on the drawn blank, with the aging temperature controlled at 450℃ and the holding time at 5h. Cooling is done by furnace cooling.

[0047] Example 2

[0048] The copper alloy material in this embodiment, by mass percentage, comprises: Ni: 5.0 wt%; Co: 0.08 wt%; Si: 1.22 wt%; Cr: 0.2 wt%, wherein Ni:Si = 4.1:1, and the balance is Cu. The specific preparation method of the copper alloy material in this embodiment is as follows:

[0049] Step 1: Melting and blank preparation are carried out using an upward-drawing furnace. The melting and holding temperature is controlled at 1200-1250℃, the traction speed is controlled at 0.7mm / s, argon gas protection is used during the traction process, and the cooling water flow rate is controlled at 12m³ / s. 3 The cooling water temperature is controlled at 20-25℃, and a qualified upper drawing blank is finally prepared.

[0050] Step 2: The above-mentioned upward-drawing blank is rolled using a cold rolling mill. The rolling is carried out continuously using multiple rolls, with the rolling speed controlled at 5 mm / s and the rolling amount controlled at 70%.

[0051] Step 3: Perform high-temperature aging treatment on the cold-rolled billet, with the aging temperature controlled at 750℃ and the holding time controlled at 50min. After the holding time is completed, water cooling is used, and the water immersion time in the converter is less than 30s.

[0052] Step 4: Perform cold drawing on the aged blank, with the single drawing amount controlled at 20-25% and the total cold drawing amount controlled at 75%.

[0053] Step 5: Perform low-temperature aging on the drawn blank, with the aging temperature controlled at 450℃ and the holding time at 7h. Cooling is done by furnace cooling.

[0054] Example 3

[0055] The copper alloy material in this embodiment, by mass percentage, comprises: Ni: 5.3 wt%; Co: 0.1 wt%; Si: 1.29 wt%; Cr: 0.3 wt%, wherein Ni:Si = 4.1:1, and the balance is Cu. The specific preparation method of the copper alloy material in this embodiment is as follows:

[0056] Step 1: Melting and blank preparation are carried out using an upward-drawing furnace. The melting and holding temperature is controlled at 1200-1250℃, the traction speed is controlled at 0.7mm / s, argon gas protection is used during the traction process, and the cooling water flow rate is controlled at 12m³ / s. 3 The cooling water temperature is controlled at 20-25℃, and a qualified upper drawing blank is finally prepared.

[0057] Step 2: The above-mentioned upward-drawing blank is rolled using a cold rolling mill. The rolling is carried out continuously using multiple rolls, with the rolling speed controlled at 5 mm / s and the rolling amount controlled at 80%.

[0058] Step 3: Perform high-temperature aging treatment on the cold-rolled billet, with the aging temperature controlled at 780℃ and the holding time controlled at 45min. After the holding time is completed, water cooling is used, and the time of water immersion in the converter is less than 30s.

[0059] Step 4: Perform cold drawing on the aged blank, with the single drawing amount controlled at 20-25% and the total cold drawing amount controlled at 75%.

[0060] Step 5: Perform low-temperature aging on the drawn blank, with the aging temperature controlled at 450℃ and the holding time at 7h. Cooling is done by furnace cooling.

[0061] Comparative Example 1

[0062] Compared to Example 1, the difference lies in the lower Ni and Si content. By mass percentage, the components include: Ni: 2.5 wt%; Co: 0.05 wt%; Si: 0.6 wt%; Cr: 0.1 wt%, where Ni:Si = 4.1:1, and the balance is Cu.

[0063] Comparative Example 2

[0064] Compared to Example 2, the difference lies in the higher Ni and Si content. By mass percentage, the components include: Ni: 6.0 wt%; Co: 0.05 wt%; Si: 1.46 wt%; Cr: 0.1 wt%, where Ni:Si = 4.1:1, and the balance is Cu.

[0065] Comparative Example 3

[0066] Compared to Example 3, the difference is that it does not contain Co and Cr elements.

[0067] Comparative Example 4

[0068] Compared to Example 1, the difference lies in step 2: the above-mentioned upward blank is rolled using a cold rolling mill, the rolling is carried out continuously with multiple rolls, the rolling speed is controlled at 5 mm / s, and the rolling amount is controlled at 50%.

[0069] Comparative Example 5

[0070] Compared to Example 2, the difference lies in step 3: the cold-rolled billet is subjected to high-temperature aging treatment, the aging temperature is controlled at 470℃, the holding time is controlled at 180min, and water cooling is used after the holding time is completed, with the converter water immersion time being less than 30s.

[0071] Comparative Example 6

[0072] Compared to Example 3, the difference lies in step 4: cold drawing is performed on the aging blank, with the single drawing amount controlled at 20-25% and the total cold drawing amount controlled at 45%.

[0073] The chemical composition of the copper alloys prepared in the examples and comparative examples is summarized in Table 1. The grain size, number of second phases, tensile strength, and electrical conductivity of the copper alloys prepared in the examples and comparative examples were tested, and the results are shown in Table 2. The specific test methods are as follows:

[0074] Second phase precipitation amount: The size of the second phase is determined by observing the microstructure of the sample under scanning electron microscope and transmission electron microscope. Based on the observation results, the average particle size and quantity of the second phase precipitated in the alloy are calculated, and its number density and the area ratio of the precipitated phase are calculated respectively.

[0075] Tensile strength and yield strength: tested in accordance with GB / T228.1-2021 "Metallic materials - Tensile testing - Part 1: Test at room temperature";

[0076] Conductivity: Tested according to GB / T32791-2016 "Eddy Current Test Method for Conductivity of Copper and Copper Alloys".

[0077] Table 1. Copper alloy composition in the examples and comparative examples.

[0078]

[0079] Figure 1 This is a size diagram of the continuous and discontinuous precipitates in the copper alloy material prepared in Example 1, from... Figure 1 It can be seen that the particle size of the continuous precipitate is ≤1μm, and the thickness of the discontinuous precipitate is ≤7μm. Figure 2 These are morphology images of the continuous and discontinuous precipitates in the copper alloy material prepared in Example 2. Figure 2 It can be seen that the continuous precipitate is granular, while the discontinuous precipitate is nanofiber-like.

[0080] Comparative Examples 1 and 2 show that both high and low Ni and Si content affect the final product performance. Too low a content prevents the formation of discontinuous precipitates, resulting in insufficient synergistic strengthening; too high a content leads to the formation of continuous eutectic phases in the blank, causing processing cracking. Comparative Example 3 shows that the absence of Co and Cr elements reduces the nucleation sites of secondary phases, thus decreasing their quantity and resulting in insufficient tensile strength. Comparative Example 4 shows that a low single-rolling depth prevents the formation of shear bands in the microstructure, leading to discontinuous formation. The continuous precipitates cannot form fibers along the processing direction, resulting in discontinuous precipitates distributed in an elliptical shape in the copper matrix, which increases the electron hindrance and causes insufficient conductivity. As shown in Comparative Example 5, a decrease in the primary aging temperature leads to an increase in the number of discontinuous precipitates, resulting in a decrease in solute in the copper matrix during subsequent aging processes, thus leading to insufficient precipitation of continuous precipitates and weakening of the strengthening synergy. As shown in Comparative Example 6, a smaller amount of secondary cold working reduces the nucleation sites of continuous phases and decreases the number of continuous phases per unit area, resulting in a decrease in material strength.

[0081] Table 2. Physical properties of copper alloys in the examples and comparative examples.

[0082]

Claims

1. A high-strength, high-conductivity copper alloy material, characterized in that, The high-strength, high-conductivity copper alloy material comprises, by mass fraction, Ni: 4.8~5.5wt%, Co: 0.05~0.1wt%, Si: 1.17~1.34wt%, Cr: 0.1~0.3wt%, with the balance being copper and unavoidable impurities; The ratio of discontinuous precipitates to continuous precipitates in the secondary strengthening phase of the high-strength, high-conductivity copper alloy material is 1:5~10. The continuous precipitates are granular with a particle size ≤4μm and a quantity >30,000 precipitates / mm². 2 The discontinuous precipitates are in the form of nanofibers with a thickness of ≤10μm.

2. The high-strength, high-conductivity copper alloy material according to claim 1, characterized in that, The mass ratio of nickel to silicon in the high-strength, high-conductivity copper alloy material is 4~4.3:

1.

3. The high-strength, high-conductivity copper alloy material according to claim 1, characterized in that, The high-strength, high-conductivity copper alloy material has a strength >1050 MPa and a conductivity ≥43% IACS.

4. The high-strength, high-conductivity copper alloy material according to claim 1, characterized in that, The grain size of the high-strength, high-conductivity copper alloy material is 15~50μm.

5. The method for preparing the high-strength, high-conductivity copper alloy material according to any one of claims 1-4, characterized in that, Includes the following steps: Ingredients Continuous casting; cold rolling; first-stage aging treatment; Cold drawing; secondary aging treatment; The cold rolling processing amount is controlled at 70-80%; the temperature of the first-stage aging treatment is controlled at 730-780℃, and the holding time is controlled at 30-60 minutes; the cold drawing processing amount is controlled at 60-75%.

6. The preparation method according to claim 5, characterized in that, During the upward continuous casting process, the melting and holding temperature is controlled at 1200~1250℃; the solid solubility of Ni2Si phase in the upward billet prepared by upward continuous casting is 5.0-5.6%, and there are discretely distributed Ni2Si eutectic phases at the grain boundaries of the upward billet.

7. The preparation method according to claim 5 or 6, characterized in that, The initial discontinuous precipitate formed during the first-stage aging process is lamellar with a thickness of ≤10μm. The initial discontinuous precipitate is coherent with the matrix and deforms in coordination with the matrix during the subsequent cold drawing process. As the deformation progresses, it exhibits a semi-coherent and incoherent relationship with the matrix.

8. The preparation method according to claim 5 or 6, characterized in that, The temperature of the secondary aging treatment is controlled at 420~450℃, and the holding time is controlled at 4~7h.

9. The application of the high-strength, high-conductivity copper alloy material according to any one of claims 1-4 in electronic appliances, aerospace or instrumentation.

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