A high-conductivity copper alloy material for cables and its preparation process and application

Abstract

The present invention provides a high-conductivity copper alloy material for cables, a preparation process and an application thereof, and belongs to the technical field of cables. The high-conductivity copper alloy material for cables comprises, by mass percentage, 98.5% to 99.2% of Cu, 0.3% to 0.8% of Ni, 0.1% to 0.5% of Sn, 0.05% to 0.2% of Ti, 0.02% to 0.1% of Cr, 0.001% to 0.005% of B, and the remainder is unavoidable impurities; the microstructure of the copper alloy comprises nanoscale precipitated phases of CuTi and CuCr, the size of the precipitated phases is 10-50nm, and the precipitation density is ≥1×10 21 m ‑3 . The preparation process of a high-conductivity copper alloy material for cables comprises the following steps: (1) vacuum melting; (2) rapid solidification; (3) hot rolling deformation; (4) aging treatment. The present invention achieves high conductivity (≥65% IACS) through the low scattering characteristics of the nano-precipitated phase, which is more than 30% higher than that of traditional Cu-Sn alloys. The synergistic strengthening of the nano-precipitated phase and the fine-grained structure enables the material to have both high strength (≥550MPa) and high plasticity (≥15% elongation), meeting the reliability requirements under complex stress environments.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and in particular to a highly conductive copper alloy material for cables, a preparation process and applications thereof. Background Art

[0002] Research on highly conductive copper alloys has long faced a core contradiction: the difficulty in synergistically improving strength and conductivity. Although traditional copper alloys (such as pure copper, brass, and bronze) have excellent conductivity, their mechanical properties are insufficient and cannot meet the modern industry's demand for lightweight and high reliability. To solve this problem, existing technologies mainly adopt two types of strategies:

[0003] Alloying method: by adding elements such as Sn, Zr, Cr to form solid solution or precipitation phase strengthening, but excessive alloying will lead to lattice distortion and significantly reduce the conductivity (such as Cu-Sn alloy conductivity ≤ 50% IACS).

[0004] Artificial composite material method: Introducing nanoparticles (such as Al2O3, carbon nanotubes) or fiber reinforcement can improve strength, but the preparation process is complicated (such as powder metallurgy requires high-pressure sintering), and interface defects can easily cause deterioration of conductivity.

[0005] In recent years, additive manufacturing techniques such as laser powder bed fusion (LPBF) have attempted to form nano-precipitates through ultra-high cooling rates. However, the oversaturated solid solution leads to severe lattice distortion, and the electrical conductivity remains below 65% IACS. Furthermore, traditional processes rely on trial and error to control the size and distribution of precipitates, lacking precise control methods, making it difficult to achieve a balanced performance.

[0006] To this end, a highly conductive copper alloy material for cables, a preparation process, and applications thereof are proposed. Summary of the Invention

[0007] The present invention aims to solve the problems raised in the background technology and provides a high-conductivity copper alloy material for cables, a preparation process and an application thereof.

[0008] The specific technical solutions are as follows:

[0009] A highly conductive copper alloy material for cables, comprising, by mass percentage:

[0010] Cu 98.5% to 99.2%, Ni 0.3% to 0.8%, Sn 0.1% to 0.5%, Ti 0.05% to 0.2%, Cr 0.02% to 0.1%, B 0.001% to 0.005%, the balance being unavoidable impurities;

[0011] The microstructure of the copper alloy contains nano-scale precipitated phases CuTi and CuCr, the size of the precipitated phases is 10-50nm, and the precipitation density is ≥1×1021 m -3 .

[0012] In the above-mentioned high-conductivity copper alloy material for cables, the volume fraction of the CuTi phase is 0.5% to 1.5%, and the volume fraction of the CuCr phase is 0.2% to 0.8%.

[0013] The above-mentioned high-conductivity copper alloy material for cables, wherein the copper alloy has a conductivity of ≥65% IACS, a tensile strength of ≥550 MPa, and an elongation of ≥15%.

[0014] In the above-mentioned highly conductive copper alloy material for cables, the unavoidable impurities include Fe, Zn, and P, and the total content thereof is ≤0.15%.

[0015] The present invention also provides a process for preparing a highly conductive copper alloy material for cables, comprising the following steps:

[0016] (1) Vacuum smelting: Electrolytic copper, nickel ingots, tin blocks, titanium particles, chromium powder and boron powder are smelted in proportion, the smelting temperature is controlled at 1150-1250°C, and the holding time is ≥30 minutes;

[0017] (2) Rapid solidification: using a double-roller rapid cooling method with a roller speed of 20-40 m / min to obtain a casting with a thickness of 0.1-0.3 mm;

[0018] (3) Hot rolling deformation: multiple passes of rolling at 800-900℃, with a total deformation of ≥70%;

[0019] (4) Aging treatment: Keep at 400-450℃ for 1-2 hours, then air cool to room temperature.

[0020] In the above-mentioned process for preparing the highly conductive copper alloy material for cables, the particle size of the titanium particles and chromium powder in step (1) is 1-10 μm.

[0021] In the above-mentioned process for preparing the highly conductive copper alloy material for cables, the deformation rate of the multiple rolling passes in step (3) is 15% to 25%.

[0022] Among them, the highly conductive copper alloy material for cables is used in 5G communication cables, new energy vehicle high-voltage wire harnesses or aerospace cables.

[0023] The present invention also provides a cable, wherein the conductor material is the copper alloy material mentioned above, the surface of the conductor is covered with an insulating layer, and the insulating layer is polyimide or fluoroplastic.

[0024] The above-mentioned cable, wherein the cross-sectional area of ​​the conductor is 0.5 to 10 mm 2, and the surface roughness Ra≤0.8μm.

[0025] The present invention has the following beneficial effects:

[0026] 1. Performance improvement:

[0027] Conductivity: Through the low scattering characteristics of the nano-precipitated phase, high conductivity (≥65% IACS) is achieved, which is more than 30% higher than that of traditional Cu-Sn alloys.

[0028] Mechanical properties: The synergistic strengthening of nano-precipitated phase and fine-grained structure enables the material to have both high strength (≥550MPa) and high plasticity (≥15% elongation), meeting the reliability requirements in complex stress environments.

[0029] 2. Process innovation:

[0030] Dynamic process window: Based on the precipitation kinetics equation, the aging temperature window is widened from the traditional 400-450°C to 380-480°C, reducing energy consumption by 15%.

[0031] Defect control: Rapid solidification (roller speed 20-40m / min) combined with vacuum melting reduces macrosegregation and porosity defects, improving material consistency.

[0032] 3. Application extension:

[0033] 5G communications: High conductivity reduces high-frequency signal attenuation and is suitable for base station cables and high-speed connectors;

[0034] New energy vehicles: High strength meets the tensile strength requirements of high-voltage wiring harnesses, and lightweight design improves endurance efficiency;

[0035] Aerospace: High-temperature resistant grain boundary strengthening properties adapt to extreme environments and extend the service life of cables.

[0036] 4. Improved economic efficiency:

[0037] By optimizing the composition, the amount of precious metals (such as Ag and Ni) added can be reduced, reducing costs by 20%-30%;

[0038] Continuous preparation processes (such as continuous casting and rolling) improve production efficiency and are suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A flow chart of a process for preparing a highly conductive copper alloy material for cables provided by an embodiment of the present invention;

[0040] Figure 2 A bar chart comparing the performance of the copper alloy material provided by the embodiment of the present invention and the copper alloy material produced by conventional processes;

[0041] Figure 3 The effect of aging temperature on conductivity and strength of a high-conductivity copper alloy material for cables provided by an embodiment of the present invention is shown in the figure;

[0042] Figure 4 A graph showing the influence of the volume fraction of the precipitated phase on the balance between strength and conductivity of a high-conductivity copper alloy material for cables provided in an embodiment of the present invention;

[0043] Figure 5 A relationship diagram between process energy consumption and cost-effectiveness of a high-conductivity copper alloy material for cables provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0045] Among them, the drawings are only used for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting this patent; in order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0046] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "inside", "outside" and the like indicate an orientation or position relationship based on the orientation or position relationship shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0047] In the description of the present invention, unless otherwise expressly specified or limited, when the term "connection" or the like appears to indicate a connection relationship between components, such term should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be internal communication between two components or an interaction between two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood in specific circumstances.

[0048] Example 1

[0049] The highly conductive copper alloy material for cables provided in this embodiment comprises, by mass percentage:

[0050] Cu 98.5% to 99.2%, Ni 0.3% to 0.8%, Sn 0.1% to 0.5%, Ti 0.05% to 0.2%, Cr 0.02% to 0.1%, B 0.001% to 0.005%, the balance being unavoidable impurities;

[0051] The microstructure of the copper alloy contains nanoscale precipitates CuTi and CuCr, with a precipitate size of 10-50 nm and a precipitation density of ≥1×10 21 m -3 .

[0052] The above technical solution, through the synergistic effect of the elements Ni, Sn, Ti, Cr, and B, overcomes the conflicting characteristics of high conductivity and high strength in traditional copper alloys. The multi-element alloying design optimizes the grain boundary strengthening mechanism, refines the grain size, and inhibits dislocation motion. Simultaneously, the solid solution strengthening and grain boundary pinning effects of the B element are utilized to reduce the tendency of grain coarsening under high-temperature service.

[0053] The volume fraction of the CuTi phase is 0.5% to 1.5%, and the volume fraction of the CuCr phase is 0.2% to 0.8%. By limiting the volume ratio of the CuTi and CuCr precipitates, the dual goals of precipitation strengthening and recrystallization suppression are achieved. Through precise control of the volume fraction, the strengthening contribution of the precipitates and the loss of conductivity are balanced, avoiding excessive lattice distortion caused by excessive precipitation.

[0054] The copper alloy has a conductivity of ≥65% IACS, a tensile strength of ≥550 MPa, and an elongation of ≥15%. Through the synergy of composition and processing, the material's conductivity, mechanical strength, and plastic deformation capacity are simultaneously enhanced. This addresses the brittleness and insufficient conductivity of traditional high-strength copper alloys, meeting the reliability requirements of cable materials in complex stress environments.

[0055] Unavoidable impurities include Fe, Zn, and P, with a total content of ≤0.15%. By strictly limiting the total amount of impurity elements such as Fe, Zn, and P, the risk of grain boundary segregation and brittle phase formation can be reduced, improving the material's fatigue resistance and long-term service stability, making it particularly suitable for high-frequency alternating load scenarios.

[0056] Among them, the volume fraction of nano-precipitated CuTi and CuCr (V CuTi 、V CuCr ) satisfies the equation for the volume fraction of the precipitated phase:

[0057]

[0058] in:

[0059] V: Actual precipitation volume fraction (unit: %), target value:

[0060] V CuTi ∈[0.5%,1.5%],V CuCr ∈[0.2%,0.8%]

[0061] V0: Maximum theoretical precipitation volume (unit: %), calculated from alloy composition:

[0062] V 0,CuTi =0.93(Ti%) 1.2 , V 0，CuCr =0.88(Cr%) 0.95

[0063] K: Cooperative kinetic factor (unit: s -1 ), value based on:

[0064]

[0065] t: aging time (unit: h), process range: 1~2h

[0066] T: Aging temperature (unit: K), process range: 673 ~ 723K (400 ~ 450℃)

[0067] Q: precipitation activation energy (unit: kJ / mol), value based on:

[0068] Q CuTi =95+30[Sn%], Q CuCr =105

[0069] n: nucleation index, the value is determined by the quenching rate: n = 0.5 + 0.02 × roller speed (m / min)

[0070] R: gas constant (unit: 8.314 J / (mol·K)).

[0071] Equation technology effects and technical principles

[0072] 1. Quantification of ingredient synergistic effects

[0073] Sn / Ni coupling effect: Sn inhibits Ti diffusion, and Ni promotes short-range order. The equation quantifies its nonlinear enhancement of CuTi precipitation through the [Sn%][Ni%] term (experiments have found that the synergistic effect is strongest when the Sn / Ni mass ratio is ≈0.25).

[0074] Catalytic effect of B: B is concentrated at the CuCr phase interface, reducing the nucleation barrier, and [B%] 0.5 The term describes its critical threshold effect (significant effect when B≥0.003%).

[0075] 2. Process dynamics reconstruction

[0076] The correlation between the quenching rate and nucleation is: roller speed → nucleation index n. High-speed quenching (40 m / min) makes n = 1.3, forming high-density fine precipitation; at low speed (20 m / min), n = 0.9, and the precipitation phase is coarsened.

[0077] The temperature-time coupling term: t·exp(-Q / RT) modifies the traditional Arrhenius formula and introduces a supersaturation decay function to avoid the decrease in conductivity caused by over-aging.

[0078] Example calculation (CuTi phase)

[0079] Input parameters:

[0080] Ti = 0.15%, Sn = 0.3%, Ni = 0.6%, B = 0.004%, roller speed = 30m / min, aging condition = 420℃ × 1.5h;

[0081] Calculation steps:

[0082] 1. V0 = 0.93 × (0.15) 1.2 =0.93×0.123=1.14%

[0083] 2.

[0084] 3. Q = 95 + 30 × 0.3 = 104 kJ / mol

[0085] 4.n=0.5+0.02×30=1.1

[0086] 5.

[0087] =1.14×[1-exp(-0.78)]=1.12%

[0088] Result: Patent requirements V are met CuTi ∈[0.5%,1.5%].

[0089] The comparison results with traditional technology are as follows:

[0090] index Traditional crafts This equation controls the process Precipitation density <![CDATA[~5×10 20 m -3 ]]> <![CDATA[≥1×10 21 m -3 ]]> Strength / conductivity 480MPa / 60%IACS 580MPa / 67%IACS Size uniformity 20-100nm(dispersion) 30±5nm (normal distribution)

[0091] Mechanism of action:

[0092] Quenching stage: double roller quenching (>10 5 K / s) freezes vacancies to form a supersaturated solid solution + high-density lattice defects, providing nucleation sites for subsequent precipitation.

[0093] Hot rolling stage: large deformation (≥70%) promotes dislocation entanglement, Sn / Ni segregates at dislocation lines, forms solute atom gas clusters, and pre-precipitates CuTi phase.

[0094] Aging stage:

[0095] Low temperature section (400-420℃): The B element segregates at the CuCr phase interface, reducing the activation energy and triggering explosive nucleation.

[0096] High temperature section (420-450℃): Ti diffusion dominates, and the drag effect of Sn slows down the growth rate, achieving self-limited growth.

[0097] The precipitate volume fraction equation establishes a multi-component synergistic factor K: the interaction between Sn / Ni / B is quantified as a calculable kinetic parameter, breaking through the limitation of traditional models that only consider a single element; the roller speed → nucleation index n is used to directly link the rapid cooling process with the precipitate distribution characteristics; the exponential term exp(-(Kt) n ) Accurately describe the drop in precipitation driving force in the later stage of aging to avoid strength / conductivity inversion;

[0098] In addition, this equation has been applied to a 5G communication cable company, and the measured conductor performance is: tensile strength 572MPa, conductivity 68%IACS, and cost reduction of 18% compared with conventional Cu-Cr-Zr alloy.

[0099] Example 2

[0100] like Figure 1-5 As shown, the difference between this embodiment and embodiment 1 is that a preparation process of a high-conductivity copper alloy material for a cable is provided, comprising the following steps:

[0101] (1) Vacuum smelting: Electrolytic copper, nickel ingots, tin blocks, titanium particles, chromium powder and boron powder are smelted in proportion, the smelting temperature is controlled at 1150°C, and the holding time is 30 minutes;

[0102] The specific proportions are as follows: by mass percentage:

[0103] Cu 98.5%, Ni 0.3%, Sn 0.1%, Ti 0.05%, Cr 0.02%, B 0.001%, the balance is unavoidable impurities;

[0104] (2) Rapid solidification: A double-roller rapid cooling method was used with a roller speed of 20 / min to obtain a casting sheet with a thickness of 0.1 mm;

[0105] (3) Hot rolling deformation: multiple passes of rolling at 800°C, with a total deformation of ≥70%;

[0106] (4) Aging treatment: Keep at 400℃ for 1 hour and air cool to room temperature.

[0107] By combining vacuum melting with rapid solidification process, component segregation is effectively avoided and a uniform nano-precipitate phase is formed; subsequent hot rolling deformation and low-temperature aging synergistically optimize the microstructure, and through precise control of dynamic recovery and recrystallization, the superimposed effect of fine grain strengthening and precipitation strengthening is obtained.

[0108] The particle size of the titanium particles and chromium powder in step (1) is 1-10 μm. By limiting the size range of the raw material particles, uniform diffusion of solute atoms is ensured during the smelting process, abnormal precipitation caused by local component oversaturation is avoided, and a uniform nucleation foundation is provided for subsequent aging treatment.

[0109] The deformation rate of the multi-pass rolling in step (3) is 15% to 25%. Through the staged deformation design, the dislocation density is gradually accumulated and dynamic recrystallization is induced, the grains are refined to the submicron level, and the residual stress is released at the same time, thereby improving the isotropic deformation capacity of the material.

[0110] in, Figure 1 The following is a flow chart showing the process for preparing the highly conductive copper alloy material for cables according to the present embodiment; Figure 2 A comparison of the three key performance indicators of conductivity, tensile strength, and elongation between the traditional process and this solution was made. The figure shows that this solution significantly outperforms the traditional process in these three areas, achieving a breakthrough balance between conductivity, strength, and plastic deformation capacity. Figure 3 The graph shows how the conductivity and strength change with increasing aging temperature within the range of 400-450°C. As can be seen from the graph, as the aging temperature increases, the conductivity decreases slightly, while the strength increases significantly. Figure 4 The figure shows how the volume fractions of the CuTi and CuCr phases balance strength and conductivity. The figure plots the relationship between the volume fractions of the CuTi and CuCr phases and the tensile strength and conductivity, respectively. It can be seen that with the increase in the volume fraction of the precipitated phase, the tensile strength increases, but the conductivity decreases slightly. The CuTi and CuCr phases have different effects on the relative strength and conductivity. The CuCr phase has a more obvious effect on improving the relative strength, but also has a greater effect on reducing the conductivity. Figure 5 The relationship between process energy consumption and cost-effectiveness is shown. It can be seen from the figure that as the process energy consumption decreases, the cost-effectiveness increases significantly.

[0111] Example 3

[0112] This embodiment differs from embodiment 2 in that a preparation process of a highly conductive copper alloy material for a cable is provided, comprising the following steps:

[0113] (1) Vacuum smelting: Electrolytic copper, nickel ingots, tin blocks, titanium particles, chromium powder and boron powder are smelted in proportion, the smelting temperature is controlled at 1200°C, and the holding time is 40 minutes;

[0114] The specific proportions are as follows: by mass percentage:

[0115] Cu99%, Ni0.5%, Sn0.3%, Ti0.1%, Cr0.05%, B0.003%, the balance is unavoidable impurities;

[0116] (2) Rapid solidification: A double-roller rapid cooling method was used with a roller speed of 30 m / min to obtain a casting sheet with a thickness of 0.2 mm;

[0117] (3) Hot rolling deformation: multiple passes of rolling at 850°C, with a total deformation of ≥70%;

[0118] (4) Aging treatment: keep at 430℃ for 1.5 hours and air cool to room temperature.

[0119] Example 4

[0120] This embodiment differs from embodiment 3 in that a preparation process of a highly conductive copper alloy material for a cable is provided, comprising the following steps:

[0121] (1) Vacuum smelting: Electrolytic copper, nickel ingots, tin blocks, titanium particles, chromium powder and boron powder are smelted in proportion, the smelting temperature is controlled at 1250°C, and the holding time is 50 minutes;

[0122] The specific proportions are as follows: by mass percentage:

[0123] Cu99.2%, Ni0.8%, Sn0.5%, Ti0.2%, Cr0.1%, B0.005%, the balance is unavoidable impurities;

[0124] (2) Rapid solidification: A double-roller rapid cooling method was used with a roller speed of 40 m / min to obtain a casting sheet with a thickness of 0.3 mm;

[0125] (3) Hot rolling deformation: multiple passes of rolling at 900°C, with a total deformation of ≥70%;

[0126] (4) Aging treatment: keep at 450℃ for 2 hours and air cool to room temperature.

[0127] Example 2-4 data comparison table:

[0128] Precipitation phase volume fraction table

[0129] <![CDATA[V CuTi (%)]]> 0.6 (calculated value) 1.0 (calculated value) 1.4 (calculated value) <![CDATA[V CuCr (%)]]> 0.3 (calculated value) 0.5 (calculated value) 0.7 (calculated value)

[0130] Performance Table

[0131] Electrical conductivity (% IACS) 68 67 65 Tensile strength (MPa) 560 580 600 Elongation (%) 16 18 15

[0132] Performance trend analysis:

[0133] Electrical conductivity: slightly decreases with the increase of the volume fraction of the precipitated phase ( Figure 4 ), due to the scattering of electrons by the precipitation phase.

[0134] Tensile strength: significantly increased with the increase of the volume fraction of the precipitated phase ( Figure 4 ), because the nanophase hinders the dislocation motion.

[0135] Elongation: Affected by fine grain structure and uniform distribution of precipitation phase, maintained ≥15%.

[0136] in conclusion

[0137] 1. Ingredient-process synergy:

[0138] Example 3 (median composition) has the best performance: conductivity 67% IACS+tensile strength 580 MPa+elongation 18%.

[0139] Ti / Cr ratio: Increasing Ti% significantly increases V CuTi (Example 4 reaches 1.4%), but an excessive amount causes the conductivity to drop to 65% IACS.

[0140] Effect of element B: When B≥0.003% (Examples 3-4), K CuCr Improved by 30%, optimizing the CuCr phase precipitation density.

[0141] 2. Process efficiency:

[0142] Roller speed increased (20→40m / min): nucleation index n increased from 0.9 to 1.3, and the size distribution of precipitated phase became more uniform ( Figure 4 ).

[0143] Aging time: 1.5 hours (Example 3) Balance precipitation kinetics and energy consumption, cost reduction of 15% ( Figure 5 ).

[0144] 3. Application adaptability:

[0145] 5G communication: Example 3 (conductivity 67% IACS) is preferably used for high-frequency, low-loss cables.

[0146] New energy vehicles: Example 4 (tensile strength 600 MPa) is suitable for high-voltage wire harness tensile scenarios.

[0147] Aerospace: Example 2 (16% elongation) meets high bending fatigue requirements.

[0148] It is worth noting that the performance data is based on patents Figure 2-4 The experimental results and the calculation of precipitation kinetics equation meet the indicators (conductivity ≥ 65% IACS, strength ≥ 550 MPa, elongation ≥ 15%).

[0149] Example 5

[0150] This embodiment provides a highly conductive copper alloy material for cable applications in 5G communication cables, high-voltage wiring harnesses for new energy vehicles, and aerospace cables. Leveraging the material's high conductivity and stability, it significantly reduces signal attenuation and electromagnetic interference in high-frequency signal transmission scenarios, meeting the technical requirements of 5G / 6G communications for low-loss and high-durability cables.

[0151] Example 6

[0152] This embodiment provides a cable whose conductor material is the copper alloy material described in Example 1 and whose surface is coated with an insulating layer made of polyimide or fluoroplastic. The corrosion-resistant insulating layer improves the cable's weather resistance and aging resistance. The cross-sectional area and surface roughness of the conductor are optimized to balance current-carrying capacity and bending fatigue life.

[0153] Among them, the cross-sectional area of ​​the conductor is 0.5~10mm 2 , and the surface roughness Ra ≤ 0.8μm. Reducing the surface roughness of the conductor reduces the increase in AC resistance caused by the skin effect, while improving the interface bonding strength between the conductor and the insulation layer to prevent delamination failure during long-term use.

[0154] Technical Advantage Comparison Table

[0155] index Traditional Cu-Sn alloy This technology copper alloy Improvement Electrical conductivity (% IACS) ≤50 ≥65 +30％ Tensile strength (MPa) ≤300 ≥550 +83％ Elongation (%) ≤10 ≥15 +50％ Process energy consumption (kWh / kg) 120 102 -15％

[0156] This solution introduces the element B into the copper alloy precipitation system, suppresses recrystallization through the grain boundary pinning effect, and breaks through the traditional alloy design paradigm; establishes a multi-factor coupled precipitation kinetics equation to achieve reverse design of process parameters and improve the technical defects of precise control of precipitation phase; through the synergistic effect of nano-precipitation phase and grain boundary engineering, a breakthrough balance is achieved between conductivity and strength, which is superior to traditional solutions.

[0157] In summary, the highly conductive copper alloy material for cables provided in this embodiment solves the conductivity-strength contradiction through multi-scale collaborative design and dynamic process control:

[0158] 1. Ingredient design principle:

[0159] Elements such as Ni, Ti, Cr, and B are introduced to form CuTi / CuCr nano-precipitates (10-50nm). Dislocation movement is suppressed by solute atom segregation, while the B element solid solution strengthens the grain boundaries and reduces high-temperature grain coarsening.

[0160] Vacuum melting and rapid solidification (double-roller rapid cooling) are used to suppress macrosegregation and obtain a uniform distribution of nano-precipitated phases.

[0161] 2. Process control principle:

[0162] Precipitation kinetics equation: Quantifies the competitive relationship between the Gibbs free energy of mixing (ΔGmix) and the work of nucleation (Q), dynamically adjusts the aging temperature (400-450°C) and time, and precisely controls the volume fraction and size of the precipitated phase.

[0163] Hot rolling-aging synergy: Multi-pass rolling (pass deformation rate 15% to 25%) introduces a dislocation network, and the precipitated phase during aging treatment hinders dislocation slip, achieving the superimposed effect of grain refinement strengthening and precipitation strengthening.

[0164] 3. Performance synergy mechanism:

[0165] The size of the nano-precipitated phase is much smaller than the electron mean free path (40nm), and the scattering of conductive electrons can be ignored, and the conductivity remains above 65% IACS;

[0166] The precipitated phase and grain boundaries work together to hinder dislocation movement, increasing the tensile strength to above 550MPa, while the elongation is ≥15%, avoiding brittle fracture.

[0167] The above are only preferred embodiments of the present invention and do not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for preparing a highly conductive copper alloy material for cables, characterized in that: The following steps are involved: (1) Vacuum smelting: Electrolytic copper, nickel ingots, tin blocks, titanium particles, chromium powder and boron powder are smelted in the following proportions by mass: Cu 98.5%-99.2%, Ni 0.3%-0.8%, Sn 0.1%-0.5%, Ti 0.05%-0.2%, Cr 0.02%-0.1%, B 0.001%-0.005%, with the remainder being unavoidable impurities. The smelting temperature is controlled at 1150-1250°C and the holding time is ≥30 minutes. (2) Rapid solidification: using a double-roller rapid cooling method with a roller speed of 20-40 m / min to obtain a casting with a thickness of 0.1-0.3 mm; (3) Hot rolling deformation: multiple passes of rolling at 800-900℃, with a total deformation of ≥70%; (4) Aging treatment: Keep at 400-450℃ for 1-2 hours, then air cool to room temperature.

2. The process for preparing a highly conductive copper alloy material for cables according to claim 1, wherein: The particle size of the titanium particles and chromium powder in step (1) is 1-10 μm.

3. The process for preparing a highly conductive copper alloy material for cables according to claim 2, wherein: The deformation rate of the multi-pass rolling in step (3) is 15% to 25%.

4. A highly conductive copper alloy material for cables, characterized in that: The high-conductivity copper alloy material for cables is prepared by the preparation process of any one of claims 1 to 3, and comprises, by mass percentage: Cu 98.5%~99.2%, Ni 0.3%~0.8%, Sn 0.1%~0.5%, Ti 0.05%~0.2%, Cr 0.02%~0.1%, B 0.001%~0.005%, the balance is unavoidable impurities; The microstructure of the copper alloy contains nano-scale precipitated phases CuTi and CuCr, the size of the precipitated phases is 10-50nm, and the precipitation density is ≥1×10 21 m -3 .

5. The highly conductive copper alloy material for cables according to claim 4, characterized in that: The volume fraction of the CuTi phase is 0.5% to 1.5%, and the volume fraction of the CuCr phase is 0.2% to 0.8%.

6. The highly conductive copper alloy material for cables according to claim 4, characterized in that: The copper alloy has an electrical conductivity of ≥65% IACS, a tensile strength of ≥550 MPa, and an elongation of ≥15%.

7. The highly conductive copper alloy material for cables according to claim 4, characterized in that: The unavoidable impurities include Fe, Zn, and P, and the total content is ≤0.15%.

8. Use of the highly conductive copper alloy material for cables according to any one of claims 4 to 7 in 5G communication cables, new energy vehicle high-voltage wire harnesses, or aerospace cables.

9. A cable, characterized in that: The conductor material is the copper alloy material according to any one of claims 4 to 7. The surface of the conductor is covered with an insulating layer, and the insulating layer is polyimide or fluoroplastic.

10. The cable according to claim 9, characterized in that The cross-sectional area of ​​the conductor is 0.5 to 10 mm², and the surface roughness Ra is ≤ 0.8 μm.

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