High-performance Cu-Ni-Co-Si alloy plate and preparation method thereof

Abstract

This invention discloses a high-performance Cu-Ni-Co-Si alloy sheet and its preparation method, relating to the field of alloy material processing technology. The alloy sheet of this invention has the following mass percentage composition: Ni: 2.3-2.55%; Co: 0.7-0.85%; Si: 0.7-0.8%; Sn: 0.05-0.1%; Zn: 0.05-0.15%; Cr: 0.15-0.3%; Zr: 0.05-0.1%; with the balance being Cu and unavoidable non-metallic impurities. This invention eliminates coarse primary phases at the source and, combined with the improvement of plasticity by microalloying elements, enables the alloy sheet to achieve a 90° bending radius (R / t) of 0, effectively solving the common industry problem of easy cracking of traditional Cu-Ni-Co-Si alloys during extreme bending.

Description

Technical Field

[0001] This invention belongs to the field of alloy material processing technology, and in particular relates to a high-performance Cu-Ni-Co-Si alloy plate and its preparation method. Background Technology

[0002] With the rapid development of 5G communication, new energy vehicles and precision electronics industry, core components such as connectors, relay springs, and lead frames are facing the stringent challenges of "miniaturization, high integration and long life". This puts forward the synergistic performance requirements of "high strength-high conductivity-excellent processability" for copper-based structural functional materials. They must have sufficient tensile strength (≥800MPa) to resist fatigue deformation during service, ensure conductivity of more than 20% IACS to achieve efficient signal transmission, and meet complex forming requirements (such as 90° bending R / t=0).

[0003] Cu-Ni-Co-Si alloys, with the core role of the (Ni,Co)₂Si precipitate strengthening phase, have become the preferred material for balancing the aforementioned properties. Their strengthening mechanism is centered on "precipitation strengthening + grain refinement strengthening + work hardening," and performance control is highly dependent on the precise ratio of Ni, Co, and Si elements and the coordinated control of multiple processes such as hot rolling, cold rolling, solution treatment, and aging. However, in actual production, the performance stability of this alloy is extremely poor: in terms of composition, an excess or imbalance in the ratio of any Ni / Co / Si element will lead to the precipitation of hard and brittle phases, causing a sharp drop in conductivity or plasticity; in terms of process, even small deviations in cold rolling rate and solution / aging parameters (such as a 10-second increase or decrease in solution time or a 20°C fluctuation in aging temperature) will cause performance deviations from the standard range by changing grain size and the state of precipitated phases (quantity / size / dispersion), resulting in a large number of scraps. Current optimization of the bending performance of Cu-Ni-Co-Si alloys largely relies on adjustments to subsequent cold rolling and aging processes, neglecting the negative impact of as-cast primary phases. These coarse, needle-like or blocky primary phases formed in the as-cast state are difficult to completely eliminate during subsequent hot rolling and solution treatment, easily becoming stress concentration sources during processing, leading to cracking during bending and preventing the achievement of the ultimate bending limit of R / t=0. Controlling the size and morphology of primary phases from the as-cast source is key to overcoming the bottleneck of synergistic high strength, high conductivity, and ultimate bending limit, and represents a technical pain point that current technologies have not yet addressed.

[0004] Therefore, the field of electronic materials urgently needs to develop a high-performance Cu-Ni-Co-Si alloy sheet and its preparation method that can solve the problem of coarse primary phase at the source and achieve high strength, high conductivity, and extreme bending performance through synergistic optimization of elements and processes. Based on this, a high-performance Cu-Ni-Co-Si alloy sheet and its preparation method are proposed, providing a solution to this problem. Summary of the Invention

[0005] The purpose of this invention is to provide a high-performance Cu-Ni-Co-Si alloy plate and its preparation method, in order to solve the defects of existing technologies such as large and difficult-to-eliminate primary phases in the as-cast state, difficulty in balancing strength and machinability, and high production costs. This invention provides a Cu-Ni-Co-Si alloy plate and its preparation method that integrates source control of primary phases in the as-cast state, multi-element synergy, and precise process control.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0007] This invention relates to a high-performance Cu-Ni-Co-Si alloy plate, wherein the mass percentage of each component in the alloy plate is as follows:

[0008] Ni: 2.3-2.55%; Co: 0.7-0.85%; Si: 0.7-0.8%; Sn: 0.05-0.1%; Zn: 0.05-0.15%; Cr: 0.15-0.3%; Zr: 0.05-0.1%; balance is Cu and unavoidable non-metallic impurities.

[0009] Furthermore, in the microstructure of the alloy sheet, the size of the as-cast primary phase... The alloy plate has a thickness of 0.05-0.3mm, a width of 45-80mm, a tensile strength of 840-880MPa, a conductivity of 42-45%IACS, and a 90° bending radius R / t ≤ 1.5.

[0010] Furthermore, the alloy sheet has a hardness of 220-300HV, a grain size of ≤0.001mm, a yield strength of 780-820MPa, and a 180° bending radius R / t of 0.5-1.5.

[0011] A method for preparing a high-performance Cu-Ni-Co-Si alloy plate includes the following steps:

[0012] Step 1: Melting and casting. Weigh the raw materials according to the proportion and melt them to obtain the alloy melt. Cast the alloy melt into a mold. During the casting process, apply mechanical vibration at a frequency of 120-150Hz to the mold. After the surface of the melt solidifies, immediately place the mold into water for rapid cooling at a cooling rate ≥100℃ / s to obtain the ingot.

[0013] Step 2: Hot rolling. After homogenization annealing, the ingot is hot rolled to obtain a hot-rolled strip.

[0014] Step 3: Cold rolling and heat treatment. The hot-rolled strip is subjected to cold rolling, solution treatment, final cold rolling and aging treatment in sequence to obtain finished alloy plates with a thickness of 0.05-0.3mm.

[0015] Furthermore, in step one, the amount of easily burnable elements Si, Cr, Zr, and Zn added is supplemented according to the burn-off coefficient, which is: Si: 1.015-1.030, Cr: 1.005-1.015, Zr: 1.15-1.25, Zn: 1.04-1.06.

[0016] Furthermore, in step one, the melting temperature is 1180℃-1250℃; the mold is a graphite mold, which is baked before casting.

[0017] Furthermore, in step two, the homogenization annealing temperature is 980℃-1000℃, and the holding time is adjusted according to the ingot thickness; the hot rolling heating temperature is 820℃-890℃, the final rolling temperature is 620℃-690℃, the total processing rate is 85-91%, and the pass processing rate is 20-25%.

[0018] Furthermore, in step three, the solution treatment temperature is 950℃ to 980℃, the holding time is 10-30s, and quenching is performed; the final cold rolling processing rate is 20-70%; the aging treatment temperature is 450℃-500℃, and the holding time is 4-10h.

[0019] Furthermore, the aging treatment temperature is 460℃-480℃, and the holding time is 8 hours.

[0020] Furthermore, in step three, a strip blank with a thickness of 0.3-1.2 mm is obtained after cold rolling, and then subjected to solution treatment, and finally thinned to 0.05-0.3 mm by cold rolling.

[0021] The present invention has the following beneficial effects:

[0022] This invention eliminates coarse primary phases at the source and improves plasticity by combining microalloying elements, enabling alloy sheets to achieve a 90° bending R / t of 0 and a 180° bending R / t ≤ 1.5. This effectively solves the common industry problem of traditional Cu-Ni-Co-Si alloys being prone to cracking during extreme bending. Furthermore, even in ultra-thin specifications with a thickness of only 0.05-0.3mm, it still maintains an excellent balance of tensile strength of 840-880MPa, electrical conductivity of 42-45% IACS, and hardness of 220-300HV, resulting in a comprehensive improvement in performance.

[0023] This invention significantly reduces raw material costs by controlling the Co content below 0.85% while maintaining or even exceeding the performance of traditional high-Co alloys.

[0024] This invention, through optimization of the as-cast structure, reduces the sensitivity to subsequent process fluctuations, improves the consistency and yield of large-scale production, and enhances process stability. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a scanning electron microscope image of the as-cast microstructure of the alloy sheet obtained in Example 1 of the present invention;

[0027] Figure 2 Here is a scanning electron microscope image of the as-cast microstructure of the alloy plate obtained in Comparative Example 4;

[0028] Figure 3 The image shows the as-cast microstructure of the alloy sheet prepared in Comparative Example 5. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1:

[0031] A method for preparing high-performance Cu-Ni-Co-Si alloy plates is provided, comprising the following steps:

[0032] Ingredients: The required dry raw materials are calculated according to the mass percentage content. The mass percentage content of each component in the alloy plate is as follows: Ni: 2.4%; Co: 0.71%; Si: 0.7%; Sn: 0.05%; Zn: 0.05%; Cr: 0.16%; Zr: 0.06%; the balance is Cu and unavoidable non-metallic impurities.

[0033] Smelting: In a 10kg smelting furnace, weigh the raw materials according to the alloy composition ratio. The easily burnable elements are proportioned according to the following burn-off coefficient ratio: Si 1.025; Cr 1.01; Zr 1.2; Zn 1.05. First, add electrolytic copper plate, pure Ni, and pure Co. After melting, add Cu-20%Si master alloy and add sufficient covering agent to prevent volatilization. Stir thoroughly for 1 minute and hold for 3 minutes. Then add Cu-20%Cr master alloy, pure Zn, and pure Sn. Pound to the bottom of the crucible and stir thoroughly for 1 minute. After complete melting, add pure Zr and hold for 3 minutes to degas. Cast. During casting, add mechanical vibration to the mold at a frequency of 120-150Hz. After the melt solidifies, place it in water and cool rapidly to reduce the formation of primary phases in the alloy. Smelting temperature: 1220℃.

[0034] Homogenization annealing: The ingot is heated in a muffle furnace under an Ar reducing atmosphere from room temperature to 980°C. The holding time is adjusted according to the thickness of the ingot. For every 10 mm increase in thickness, the holding time is increased by 1 hour. The ingot is heated and cooled in the furnace.

[0035] Hot rolling: In an Ar reducing atmosphere, the ingot is heated in a muffle furnace. The ingot is heated from room temperature to 850°C, held for 5 minutes, and then exited the furnace at 750°C. The final rolling temperature is 650°C, with a total processing rate of 90% and a pass processing rate of 23%.

[0036] Cold rolling: The alloy ingot is hot rolled to obtain a strip blank with a thickness of 3mm; then the 3mm thick strip blank is cold rolled to reduce its thickness to 0.3mm.

[0037] Cleaning: The 0.3mm thick cold-rolled strip is cleaned to remove surface grease and oxides; after cleaning, the strip is trimmed to a width of 50mm.

[0038] Solution treatment: The strip after cleaning is subjected to high-temperature solution treatment. The solution treatment process is as follows: holding at a temperature of 980℃ for 20 seconds and quenching to obtain a supersaturated solid solution.

[0039] Final cold rolling and aging: The whole coil of strip after solution treatment is rolled from 0.3mm to 0.1mm, and then subjected to aging treatment at 460℃ for 8 hours to obtain the final product.

[0040] Ni is one of the most critical elements in Cu-Ni-Co-Si alloys, and its core role is to form with Si. Precipitation-enhanced phase, The coherent relationship with the Cu matrix effectively hinders dislocation slip, while the dispersed second phase is crucial for the alloy's strength, elasticity, and electrical conductivity. Insufficient Ni content will cause… Insufficient precipitation significantly weakens the strengthening effect. When the Ni content is too high, some Ni will not be able to combine with Si and will remain in the Cu matrix in a solid solution state, which will lead to a significant decrease in the conductivity of the alloy; the precipitated phase is coarse; but the strength will be improved.

[0041] The atomic radii of Co and Ni (Ni: 0.124 nm, Co: 0.125 nm) are almost identical, and Co can be completely dissolved in Ni. Selected, formed Solid solutions, this solid solution substitution produces the following effects: refinement Higher phase size dispersion results in a more significant strengthening effect; it also enhances phase stability. The lattice energy of the phase is higher than that of the pure phase. At high temperatures (200-250℃), the roughening rate decreases by 60-70%, avoiding strength degradation caused by over-aging; it enhances the phase's resistance to dislocation shearing, and the higher atomic number of Co results in stronger bond energy with Si, making... The phase hardness increases by 15-20%, and more energy is required when dislocations cut through particles.

[0042] Si element is Si is an "essential element" for precipitated phases; without Si, a core strengthening phase cannot be formed, and the Si content directly determines the formation of the core strengthening phase. The amount, size, and distribution of precipitated phases play a "quantitative control" role in the alloy properties. After Si precipitates, it has a smaller impact on conductivity (elements such as Fe and Mn have high solid solubility, and some remain after aging, with conductivity of only 10-20% IACS). This is one of the key reasons why Cu-Ni-Co-Si alloys can achieve both high strength and conductivity.

[0043] Sn, when added as a microalloying element, improves plasticity and toughness by refining the microstructure and homogenizing its distribution, thereby improving the alloy's bending workability, reducing the risk of cracking, and having little impact on the alloy's electrical conductivity.

[0044] The solid solubility of Zn in Cu is as high as 30 wt%, therefore Zn exists almost in a solid solution state in the Cu matrix and does not participate in the formation of Cu matrix. The nucleation and growth of the phase do not significantly alter its crystal structure, size, and dispersion; they only strengthen through solid solution. The precipitation and strengthening process forms a "synergistic strengthening system".

[0045] Cr element refines the microstructure and forms Cr-rich composite strengthening phases. Synergistic strengthening significantly improves the alloy's room temperature corrosion resistance, strength, hardness, and slight thermal stability while slightly reducing conductivity (1-3% IACS). However, excessive amounts can easily lead to a decrease in toughness.

[0046] Zr element contributes to strong grain refinement and the formation of Cu-Zr / Zr-Si composite strengthening phases. The synergistic effect of the phases significantly optimizes the yield strength, elastic limit, precision machinability, and greatly improves the thermal stability of the alloy without compromising or even slightly improving its conductivity. However, excessive amounts can easily form coarse phases, leading to elastic degradation.

[0047] Example 2:

[0048] A method for preparing high-performance Cu-Ni-Co-Si alloy plates is provided, comprising the following steps:

[0049] Ingredients: The required dry raw materials are calculated according to the mass percentage content. The mass percentage content of each component in the alloy plate is as follows: Ni: 2.4%; Co: 0.71%; Si: 0.7%; Sn: 0.05%; Zn: 0.05%; Cr: 0.16%; Zr: 0.06%; the balance is Cu and unavoidable non-metallic impurities.

[0050] Smelting: In a 10kg smelting furnace, weigh the raw materials according to the alloy composition ratio. The easily burnable elements are proportioned according to the following burn-off coefficient ratio: Si 1.025; Cr 1.01; Zr 1.2; Zn 1.05. First, add electrolytic copper plate, pure Ni, and pure Co. After melting, add Cu-20%Si master alloy and add sufficient covering agent to prevent volatilization. Stir thoroughly for 1 minute and hold for 3 minutes. Then add Cu-20%Cr master alloy, pure Zn, and pure Sn. Pound to the bottom of the crucible and stir thoroughly for 1 minute. After complete melting, add pure Zr and hold for 3 minutes to degas. Cast. During casting, add mechanical vibration to the mold at a frequency of 120-150Hz. After the melt solidifies, place it in water and cool rapidly to reduce the formation of primary phases in the alloy. Smelting temperature: 1220℃.

[0051] Homogenization annealing: The ingot is heated in a muffle furnace under an Ar reducing atmosphere from room temperature to 980°C. The holding time is adjusted according to the thickness of the ingot. For every 10 mm increase in thickness, the holding time is increased by 1 hour. The ingot is heated and cooled in the furnace.

[0052] Hot rolling: The ingot is heated in a muffle furnace under an Ar reducing atmosphere. The ingot is heated from room temperature to 850°C, held for 5 minutes, and then exited the furnace at 750°C. The final rolling temperature is 650°C, with a total processing rate of 90% and a pass processing rate of 22%.

[0053] Cold rolling: The alloy ingot is hot rolled to obtain a strip blank with a thickness of 3mm; then the 3mm thick strip blank is cold rolled to reduce its thickness to 0.3mm.

[0054] Cleaning: The 0.3mm thick cold-rolled strip is cleaned to remove surface grease and oxides; after cleaning, the strip is trimmed to a width of 50mm.

[0055] Solution treatment: The strip after cleaning is subjected to high-temperature solution treatment. The solution treatment process is as follows: holding at a temperature of 980℃ for 20 seconds and quenching to obtain a supersaturated solid solution.

[0056] Final cold rolling and aging: The whole coil of strip after solution treatment is rolled from 0.3mm to 0.24mm, and then subjected to aging treatment at 460℃ for 8 hours to obtain the final product.

[0057] Example 3:

[0058] A method for preparing high-performance Cu-Ni-Co-Si alloy plates is provided, comprising the following steps:

[0059] Ingredients: The required dry raw materials are calculated according to the mass percentage content. The mass percentage content of each component in the alloy plate is as follows: Ni: 2.4%; Co: 0.71%; Si: 0.7%; Sn: 0.05%; Zn: 0.05%; Cr: 0.16%; Zr: 0.06%; the balance is Cu and unavoidable non-metallic impurities.

[0060] Smelting: In a 10kg smelting furnace, weigh the raw materials according to the alloy composition ratio. The easily burnable elements are proportioned according to the following burn-off coefficient ratio: Si 1.025; Cr 1.01; Zr 1.2; Zn 1.05. First, add electrolytic copper plate, pure Ni, and pure Co. After melting, add Cu-20%Si master alloy and add sufficient covering agent to prevent volatilization. Stir thoroughly for 1 minute and hold for 3 minutes. Then add Cu-20%Cr master alloy, pure Zn, and pure Sn. Pound to the bottom of the crucible and stir thoroughly for 1 minute. After complete melting, add pure Zr and hold for 3 minutes to degas. Cast. During casting, add mechanical vibration to the mold at a frequency of 120-150Hz. After the melt solidifies, place it in water and cool rapidly to reduce the formation of primary phases in the alloy. Smelting temperature: 1220℃.

[0061] Homogenization annealing: The ingot is heated in a muffle furnace under an Ar reducing atmosphere from room temperature to 980°C. The holding time is adjusted according to the thickness of the ingot. For every 10 mm increase in thickness, the holding time is increased by 1 hour. The ingot is heated and cooled in the furnace.

[0062] Hot rolling: In an Ar reducing atmosphere, the ingot is heated in a muffle furnace. The ingot is heated from room temperature to 850°C, held for 5 minutes, and then exited the furnace at 750°C. The final rolling temperature is 650°C, with a total processing rate of 90% and a pass processing rate of 23%.

[0063] Cold rolling: The alloy ingot is hot rolled to obtain a strip blank with a thickness of 3mm; then the 3mm thick strip blank is cold rolled to reduce its thickness to 1.2mm.

[0064] Cleaning: The 1.2mm thick cold-rolled strip is cleaned to remove surface grease and oxides; after cleaning, the strip is trimmed to a width of 45mm.

[0065] Solution treatment: The strip after cleaning is subjected to high-temperature solution treatment. The solution treatment process is as follows: holding at a temperature of 960℃ for 120s and quenching to obtain a supersaturated solid solution.

[0066] Final cold rolling and aging: The whole coil of strip after solution treatment is rolled from 1.2mm to 0.3mm, and then subjected to aging treatment at 480℃ for 8 hours to obtain the final product.

[0067] Example 4:

[0068] A method for preparing high-performance Cu-Ni-Co-Si alloy plates is provided, comprising the following steps:

[0069] Ingredients: The required dry raw materials are calculated according to the mass percentage content. The mass percentage content of each component in the alloy plate is as follows: Ni: 2.4%; Co: 0.71%; Si: 0.7%; Sn: 0.05%; Zn: 0.05%; Cr: 0.16%; Zr: 0.06%; the balance is Cu and unavoidable non-metallic impurities.

[0070] Smelting: In a 10kg smelting furnace, weigh the raw materials according to the alloy composition ratio. The easily burnable elements are proportioned according to the following burn-off coefficient ratio: Si 1.025; Cr 1.01; Zr 1.2; Zn 1.05. First, add electrolytic copper plate, pure Ni, and pure Co. After melting, add Cu-20%Si master alloy and add sufficient covering agent to prevent volatilization. Stir thoroughly for 1 minute and hold for 3 minutes. Then add Cu-20%Cr master alloy, pure Zn, and pure Sn. Pound to the bottom of the crucible and stir thoroughly for 1 minute. After complete melting, add pure Zr and hold for 3 minutes to degas. Cast. During casting, add mechanical vibration to the mold at a frequency of 120-150Hz. After the melt solidifies, place it in water and cool rapidly to reduce the formation of primary phases in the alloy. Smelting temperature: 1220℃.

[0071] Homogenization annealing: The ingot is heated in a muffle furnace under an Ar reducing atmosphere from room temperature to 980°C. The holding time is adjusted according to the thickness of the ingot. For every 10 mm increase in thickness, the holding time is increased by 1 hour. The ingot is heated and cooled in the furnace.

[0072] Hot rolling: In an Ar reducing atmosphere, the ingot is heated in a muffle furnace. The ingot is heated from room temperature to 850°C, held for 5 minutes, and then exited the furnace at 750°C. The final rolling temperature is 650°C, with a total processing rate of 90% and a pass processing rate of 23%.

[0073] Cold rolling: The alloy ingot is hot rolled to obtain a strip blank with a thickness of 3mm; then the 3mm thick strip blank is cold rolled to reduce its thickness to 0.3mm.

[0074] Cleaning: The 0.3mm thick cold-rolled strip is cleaned to remove surface grease and oxides; after cleaning, the strip is trimmed to a width of 50mm.

[0075] Solution treatment: The strip after cleaning is subjected to high-temperature solution treatment. The solution treatment process is as follows: holding at a temperature of 980℃ for 300s and quenching to obtain a supersaturated solid solution.

[0076] Final cold rolling and aging: The whole coil of strip after solution treatment is rolled from 0.3mm to 0.1mm, and then subjected to aging treatment at 460℃ for 8 hours to obtain the final product.

[0077] Example 5:

[0078] A method for preparing high-performance Cu-Ni-Co-Si alloy plates is provided, comprising the following steps:

[0079] Ingredients: The required dry raw materials are calculated according to the mass percentage content. The mass percentage content of each component in the alloy plate is as follows: Ni: 2.4%; Co: 0.71%; Si: 0.7%; Sn: 0.05%; Zn: 0.05%; Cr: 0.16%; Zr: 0.06%; the balance is Cu and unavoidable non-metallic impurities.

[0080] Smelting: In a 10kg smelting furnace, weigh the raw materials according to the alloy composition ratio. The easily burnable elements are proportioned according to the following burn-off coefficient ratio: Si 1.025; Cr 1.01; Zr 1.2; Zn 1.05. First, add electrolytic copper plate, pure Ni, and pure Co. After melting, add Cu-20%Si master alloy and add sufficient covering agent to prevent volatilization. Stir thoroughly for 1 minute and hold for 3 minutes. Then add Cu-20%Cr master alloy, pure Zn, and pure Sn. Pound to the bottom of the crucible and stir thoroughly for 1 minute. After complete melting, add pure Zr and hold for 3 minutes to degas. Cast. During casting, add mechanical vibration to the mold at a frequency of 120-150Hz. After the melt solidifies, place it in water and cool rapidly to reduce the formation of primary phases in the alloy. Smelting temperature: 1220℃.

[0081] Homogenization annealing: The ingot is heated in a muffle furnace under an Ar reducing atmosphere from room temperature to 980°C. The holding time is adjusted according to the thickness of the ingot. For every 10 mm increase in thickness, the holding time is increased by 1 hour. The ingot is heated and cooled in the furnace.

[0082] Hot rolling: In an Ar reducing atmosphere, the ingot is heated in a muffle furnace. The ingot is heated from room temperature to 850°C, held for 5 minutes, and then exited the furnace at 750°C. The final rolling temperature is 650°C, with a total processing rate of 90% and a pass processing rate of 23%.

[0083] Cold rolling: The alloy ingot is hot rolled to obtain a strip blank with a thickness of 3mm; then the 3mm thick strip blank is cold rolled to reduce its thickness to 0.3mm.

[0084] Cleaning: The 0.3mm thick cold-rolled strip is cleaned to remove surface grease and oxides; after cleaning, the strip is trimmed to a width of 50mm.

[0085] Solution treatment: The strip after cleaning is subjected to high-temperature solution treatment. The solution treatment process is as follows: holding at a temperature of 980℃ for 20 seconds and quenching to obtain a supersaturated solid solution.

[0086] Final cold rolling and aging: The whole coil of strip after solution treatment is rolled from 0.3mm to 0.1mm, and then subjected to aging treatment at 500℃ for 8 hours to obtain the final product.

[0087] Table 1. Alloy composition formulas for Comparative Examples 1-14

[0088]

[0089] Table 2 Comparison of performance test results between Examples 1-5 and Comparative Examples 1-14

[0090]

[0091] Comparative Example 1:

[0092] The difference from Example 1 is that the Ni content is too high. The specific alloy composition formula is shown in Table 1.

[0093] Comparative Example 2:

[0094] The difference from Example 1 is that the Co content is too high. The specific alloy composition formula is shown in Table 1.

[0095] Comparative Example 3:

[0096] The difference from Example 1 is that the content of Si is too high. The specific alloy composition formula is shown in Table 1.

[0097] Comparative Example 4:

[0098] The difference from Example 1 is that air cooling is used during casting, and the specific alloy composition formula is shown in Table 1.

[0099] Comparative Example 5:

[0100] The difference from Example 1 is that water cooling is still used for casting, but the mechanical vibration of the mold during casting is eliminated. The specific alloy composition formula is shown in Table 1.

[0101] Comparative Example 6:

[0102] The difference from Example 1 is that there is no homogenization annealing, and the specific alloy composition formula is shown in Table 1.

[0103] Comparative Example 7:

[0104] The difference from Example 1 is that the hot rolling temperature is 950°C, and the specific alloy composition formula is shown in Table 1.

[0105] Comparative Example 8:

[0106] The difference from Example 1 is that the solution treatment process is 970℃ / 20s, and the specific alloy composition formula is shown in Table 1.

[0107] Comparative Example 9:

[0108] The difference from Example 1 is that the aging process is 420℃ / 8h, and the specific alloy composition formula is shown in Table 1.

[0109] Comparative Example 10:

[0110] The difference from Example 1 is that no microalloying elements are added, and the specific alloy composition formula is shown in Table 1.

[0111] Comparative Example 11:

[0112] The difference from Example 1 is that only Sn is added as a microalloying element, and the specific alloy composition formula is shown in Table 1.

[0113] Comparative Example 12:

[0114] The difference from Example 1 is that only Zn is added as a microalloying element, and the specific alloy composition formula is shown in Table 1.

[0115] Comparative Example 13:

[0116] The difference from Example 1 is that only Cr is added as a microalloying element, and the specific alloy composition formula is shown in Table 1.

[0117] Comparative Example 14:

[0118] The difference from Example 1 is that only Zr is added as a microalloying element, and the specific alloy composition formula is shown in Table 1.

[0119] In Example 1, the Cu-Ni-Co-Si alloy achieved a hardness of 267 HV, electrical conductivity of 45.7% IACS, grain size ≤0.001 mm, tensile strength of 864.6 MPa, yield strength of 823.1 MPa, 90° bending R / t=0, 180° bending R / t=0.5, and synergistic optimization of properties and microstructure.

[0120] In Example 2, the cold rolling rate was reduced, and the decrease in work hardening resulted in a slight decrease in performance.

[0121] In Example 3, the cold rolling rate is the lowest. The reduction in cold rolling amount leads to a decrease in aging precipitation, a significant decrease in electrical conductivity and hardness, and the thicker dimensions also affect bending performance.

[0122] In Example 4, the solution time was changed to 300s, which resulted in the growth of alloy grain size and a decrease in strength after solution treatment. Excessive solution time also caused some precipitated phases to precipitate prematurely, and the precipitated phases grew larger during the subsequent aging process, resulting in a decrease in electrical conductivity.

[0123] In Example 5, the aging temperature was increased to 500℃, which significantly improved electrical conductivity and plasticity, but reduced strength and hardness.

[0124] In Comparative Example 1, the excessive amount of Ni led to an increase in alloy strength, a significant decrease in electrical conductivity, and a decline in bending performance.

[0125] In Comparative Example 2, the excessive amount of Co led to an increase in alloy strength, a decrease in electrical conductivity, and a decrease in bending performance.

[0126] In Comparative Example 3, the excessive amount of Si element led to a decrease in alloy strength, electrical conductivity, and bending performance.

[0127] In Comparative Example 4, the cooling method after casting was changed from water cooling to air cooling. The reduced cooling rate resulted in a larger size of the primary phase, such as... Figure 2 As shown, the primary phase is extremely difficult to remove in subsequent processes, resulting in a decrease in the alloy's strength, plasticity, electrical conductivity, and processing performance.

[0128] In Comparative Example 5, water cooling was still used for casting, but the mechanical vibration of the mold during casting was removed. The core function of mechanical vibration is to refine the grains and eliminate defects. Although the grain refinement and suppression of primary phases by rapid cooling of water were retained, the quality of the casting was significantly reduced, which in turn caused a decline in the alloy properties.

[0129] In Comparative Example 6, the absence of homogenization annealing resulted in alloy microstructure segregation. Even with the presence of high-temperature solution treatment, the uniformity of composition could not be recovered, leading to differences in composition between samples taken from different locations and consequently a decrease in alloy performance.

[0130] In Comparative Example 7, a higher hot rolling temperature leads to larger alloy grain size and increased electrical conductivity, but reduced mechanical properties.

[0131] In Comparative Example 8, the solution temperature was reduced by 10℃, resulting in a partially processed microstructure after solution treatment. The solution treatment effect was reduced, which suppressed the precipitation of precipitates during subsequent cold rolling. Due to the incomplete elimination of work hardening, the sample exhibited non-uniform properties, with some areas having higher hardness. The overall plasticity of the alloy decreased, the electrical conductivity decreased, and the processing performance was significantly reduced.

[0132] In Comparative Example 9, when the aging temperature was lowered to 420℃, the alloy precipitate phase was not completely precipitated, and the alloy was in an under-aged state, with its performance not reaching its peak.

[0133] In Comparative Example 10, the absence of microalloying elements led to varying degrees of decline in all properties of the alloy, especially its bending performance.

[0134] In Comparative Example 11, only Sn was added. Compared with Comparative Example 9, the hardness and strength were slightly improved, but the electrical conductivity was slightly decreased, and the bending performance was partially improved.

[0135] In Comparative Example 12, only Zn was added. Compared with Comparative Example 9, the hardness and strength were slightly improved, the electrical conductivity remained the same, and the bending performance was partially improved.

[0136] In Comparative Example 13, only Cr was added. Compared with Comparative Example 9, the hardness, strength, and electrical conductivity were slightly improved, but the elongation was slightly reduced, and there was no cracking in the bending performance.

[0137] In Comparative Example 14, only Zr was added, and compared with Comparative Example 9, the mechanical properties were slightly improved, and the bending performance was good.

[0138] In summary, through a systematic comparison of the embodiments and comparative examples, it is fully demonstrated that the preparation method of the high-performance Cu-Ni-Co-Si alloy plate provided by the present invention is a well-thought-out, non-obvious, and complete technical solution that can produce synergistic effects.

[0139] Furthermore, regarding the core strengthening mechanism of the preparation method of the high-performance Cu-Ni-Co-Si alloy plate provided in Example 1:

[0140] The performance of Example 1 reached its peak: hardness 267HV, conductivity 45.7%IACS, tensile strength 864.6MPa, and 90° bending R / t=0. The core of this performance is the triple superposition mechanism of "control of primary phase in as-cast state + synergistic strengthening of multiple elements + precise matching of processes".

[0141] Strengthening of primary phases in as-cast state: 120-150Hz mechanical vibration + water cooling (≥100℃ / s) controls the size of primary phases (Ni2Si, (Ni,Co)2Si) within a certain range. (Round and granular), without coarse needle-like / blocky phases, eliminating stress concentration sources from the source and laying the foundation for subsequent processability;

[0142] Multi-element synergistic enhancement:

[0143] Main strengthening system: Ni / Co / Si are precisely proportioned to form a fine and dispersed (Ni,Co)2Si precipitate phase, which enhances strength through "dislocation hindrance + coherent strengthening" and fully precipitates to purify the matrix and ensure conductivity;

[0144] Auxiliary strengthening: Sn / Zn solid solution strengthening (lattice distortion hinders dislocation) + Cr / Zr composite strengthening (Cr-rich phase, Cu-Zr phase refines grains + promotes (Ni,Co)2Si nucleation), the four elements synergistically optimize the balance of "strength-conductivity-plasticity";

[0145] Precise matching of process parameters: 980℃ / 20s solution treatment (fully dissolved without grain growth) + 30% cold rolling rate (introducing an appropriate amount of dislocations as nucleation sites for precipitates) + 460℃ / 8h aging (peak precipitation of (Ni,Co)2Si phase, without coarsening), achieving optimal synergy between work hardening and precipitation strengthening.

[0146] Comparison of Example 1 with other examples and differences in mechanism:

[0147] 1. Example 1 vs. Example 2 (Cold rolling rate reduction: 30% → 20%)

[0148] Parameter differences: The final cold rolling rate decreased from 30% (0.3mm→0.1mm) to 20% (0.3mm→0.24mm).

[0149] Performance changes: Hardness 267HV→255HV, tensile strength 864.6MPa→854.3MPa, bending R / t=0→1;

[0150] Mechanistic differences:

[0151] Example 1: A 30% cold rolling rate introduces sufficient dislocations, providing ample nucleation sites for the (Ni,Co)2Si phase, resulting in a synergistic effect between precipitation strengthening and work hardening;

[0152] Example 2: The reduction in cold rolling rate leads to a decrease in dislocation density, a decrease in the nucleation rate of (Ni,Co)2Si phase, a slight decrease in dispersion, and a weakening of work hardening effect, resulting in a slight decline in strength / hardness; however, the control of primary phase and elemental synergy remain unchanged, and the conductivity and plasticity are basically stable.

[0153] 2. Example 1 vs. Example 3 (extremely low cold rolling rate + increased thickness)

[0154] Parameter differences: cold rolling rate decreased, finished product thickness increased from 0.1mm to 0.3mm, and solution treatment time was extended to 120s;

[0155] Performance changes: Hardness 267HV→246HV, conductivity 45.7%→42.3%, 90° bending R / t=0→1.5;

[0156] Mechanistic differences:

[0157] Example 1: Moderate cold rolling + thin thickness, uniform dislocation distribution, sufficient nucleation sites, uniform stress transmission along the thickness, and no cracking when bending;

[0158] Example 3: ① Low cold rolling rate → dislocation density drops sharply, insufficient nucleation of (Ni,Co)2Si phase, precipitation strengthening fails, strength / conductivity decreases; ② Thickness causes uneven stress distribution along the cross section, coupled with slight grain growth caused by prolonged solid solution time, stress concentration cannot be released during bending, and processability deteriorates.

[0159] 3. Example 1 vs. Example 4 (solution time too long: 20s → 300s)

[0160] Parameter differences: Solution treatment time increased from 20s to 300s;

[0161] Performance changes: Hardness 267HV→232HV, tensile strength 864.6MPa→800.3MPa, electrical conductivity 45.7%→40.1%;

[0162] Mechanistic differences:

[0163] Example 1: Solid solution in 20s achieves complete elemental dissolution without grain growth or pre-precipitated phases;

[0164] Example 4: 300s long solid solution treatment leads to: ① grain merging and growth (fine grain strengthening failure); ② the supersaturated solid solution is unstable, some precipitated phases precipitate prematurely and coarsen, the overall dispersion of (Ni,Co)2Si phase decreases during subsequent aging, and the strengthening effect is weakened; ③ the coarse phases enhance electron scattering and reduce conductivity.

[0165] 4. Example 1 vs. Example 5 (Aging temperature too high: 460℃→500℃)

[0166] Parameter differences: Aging temperature increased from 460℃ to 500℃;

[0167] Performance changes: Hardness 267HV→228HV, tensile strength 864.6MPa→805.3MPa, electrical conductivity 45.7%→46.8%;

[0168] Mechanistic differences:

[0169] Example 1: 460℃ is the peak precipitation temperature of (Ni,Co)2Si phase. The phase size is small (≤50nm), the dispersion is uniform, and the strengthening effect is the best.

[0170] Example 5: In the aging range of 500℃, the diffusion and coarsening rate of the (Ni,Co)2Si phase is accelerated, the phase size is increased (≥80nm), the hindering effect on dislocations is weakened, and the strength / hardness decreases; however, the precipitated phase is fully precipitated (even slightly over-aged), the residual solid solution elements in the matrix are reduced, and the conductivity is slightly improved.

[0171] Comparison of Example 1 and Comparative Example, and Analysis of Mechanism Deterioration:

[0172] 1. Comparative examples with excess components (Comparative Examples 1-3: Ni / Co / Si in excess)

[0173] Parameter differences: Comparative Example 1 (Ni=2.8%), Comparative Example 2 (Co=0.96%), and Comparative Example 3 (Si=1.01%) deviate from the optimal ratio of Example 1;

[0174] Performance degradation: Strength increases slightly but conductivity drops sharply (35-36% IACS), bending R / t ≥ 2.0 (cracking);

[0175] Mechanism deterioration:

[0176] The stoichiometric ratio that disrupts the (Ni,Co)2Si phase is as follows: When Ni / Co is in excess, some elements cannot form precipitates and remain in solid solution or form hard and brittle phases (such as Ni3Si and Cu9Co2). Strong electron scattering leads to a decrease in conductivity, and the hard and brittle phase becomes a stress concentration source, causing bending and cracking.

[0177] When Si is in excess, coarse Ni3Si phase + Si elemental inclusions are formed, which disrupts the uniform distribution of (Ni,Co)2Si phase, causes precipitation strengthening to fail, and reduces strength and plasticity simultaneously.

[0178] 2. Comparative examples of missing casting process (Comparative examples 4-5: air cooling / no vibration)

[0179] Parameter differences: Comparative Example 4 (air cooling, cooling rate ≤20℃ / s), Comparative Example 5 (no vibration, water cooling only);

[0180] Performance degradation: The primary phase size of Comparative Example 4 increased to (Needle-shaped / block-shaped), tensile strength ≤795MPa, conductivity ≤40.2%, bending radius R / t ≥2;

[0181] Mechanism deterioration:

[0182] In Example 1, the "vibration + water cooling" method inhibited the growth of the primary phase, resulting in a rounded and fine tissue structure. Figure 1 ;

[0183] Comparative Example 4: Insufficient air cooling rate allows the primary phase ample time to grow into coarse needle-like structures, which cannot be eliminated by subsequent hot rolling / solution treatment, thus becoming a source of processing cracks. (See...) Figure 2 ;

[0184] Comparative Example 5: Without vibration, molten pool gas stagnation occurs, leading to micropores and uneven primary phase distribution. Stress concentrates at defects, making bending prone to cracking. (See...) Figure 3 .

[0185] 3. Comparative examples of process deficiencies / parameter deviations (Comparative examples 6-9)

[0186] Comparative Example 6 (without homogenization annealing):

[0187] Mechanism deterioration: As-cast dendrite segregation is not eliminated, Ni / Co / Si is unevenly distributed within / between grains, coarse phases form in element-rich regions, and strengthening phases are insufficient in element-poor regions, resulting in uneven performance and overall degradation.

[0188] Comparative Example 7 (hot rolling temperature 950℃):

[0189] Mechanism deterioration: Excessive hot rolling temperature leads to grain growth (failure of fine grain strengthening) and a decrease in mechanical properties; however, high temperature promotes the precipitation of phases, resulting in a slight increase in conductivity (sacrificing strength for conductivity).

[0190] Comparative Example 8 (solution temperature 970℃):

[0191] Mechanism deterioration: Insufficient solution temperature leads to a decrease in Ni / Co / Si solid solubility, some precipitated phases remain undissolved, residual processed structure remains, uneven distribution of precipitated phases during subsequent aging, and fluctuating performance with decreased plasticity and conductivity;

[0192] Comparative Example 9 (aging temperature 420℃):

[0193] Mechanism deterioration: The aging temperature is too low, the nucleation and growth rate of the (Ni,Co)2Si phase is slow, and it is in an under-aged state. The number of precipitated phases is insufficient and the dispersion is poor. The strength and conductivity do not reach the peak value.

[0194] 4. Comparative examples of microalloying element deficiency (Comparative examples 10-14)

[0195] Parameter differences: Comparative Example 10 (no microalloying), Comparative Examples 11-14 (single microalloying).

[0196] Performance degradation: Hardness ≤235HV, tensile strength ≤860MPa, bending radius R / t ≥2.0;

[0197] Mechanism deterioration:

[0198] The synergistic effect of "Sn+Zn+Cr+Zr" in Example 1: Sn / Zn solid solution strengthening, Cr / Zr grain refinement + promotion of precipitation phase nucleation, and the four elements superimposed to optimize performance;

[0199] Comparative Example 10: Without auxiliary strengthening, relying solely on the (Ni,Co)2Si phase, the grains are coarse, the dispersion of precipitated phases is insufficient, and both strength and processability decrease.

[0200] Comparative Examples 11-14: A single element cannot achieve synergy. For example, adding only Sn can only slightly strengthen the solid solution, and adding only Cr can only refine the grains. Neither can take into account strength, conductivity and processability. The strengthening effect is far lower than that of Example 1.

[0201] Therefore, the performance of Cu-Ni-Co-Si alloys is essentially the result of a balance of four core elements: primary phase state, precipitated phase state, grain size, and elemental synergy.

[0202] Example 1 achieves optimal balance of four key elements through “refinement of as-cast primary phase + multi-element synergy + precise process matching”, thereby achieving synergy of “high strength - high conductivity - extreme bending”.

[0203] Other embodiments show a slight decline in performance due to deviations in a single process parameter (cold rolling rate, solution treatment time, aging temperature) that disrupt the balance of a certain element (such as dislocation density, precipitate size);

[0204] The comparison showed that excessive components, incomplete processes, or single elements directly damaged the core strengthening mechanism (such as coarse primary phase, abnormal precipitates, and loss of synergistic effect), resulting in significant performance degradation.

[0205] This pattern verifies the necessity and superiority of the innovative design of "cast primary phase control + multi-element synergy + process synergy" in this invention.

[0206] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high-performance Cu-Ni-Co-Si alloy plate, characterized in that, The mass percentage of each component in the alloy sheet is as follows: Ni: 2.3-2.55%; Co: 0.7-0.85%; Si: 0.7-0.8%; Sn: 0.05-0.1%; Zn: 0.05-0.15%; Cr: 0.15-0.3%; Zr: 0.05-0.1%; balance is Cu and unavoidable non-metallic impurities; In the microstructure of the alloy sheet, the size of the as-cast primary phase is ≤5μm; The alloy plate has a thickness of 0.05-0.3 mm, a width of 45-80 mm, a tensile strength of 840-880 MPa, a conductivity of 42-45% IACS, a 90° bending radius R / t ≤ 1.5, a hardness of 220-300 HV, a grain size ≤ 0.001 mm, a yield strength of 780-820 MPa, and a 180° bending radius R / t = 0.5-1.

5. The alloy sheet is prepared by a method comprising the following steps: Step 1: Melting and casting. Weigh the raw materials according to the proportion and melt them to obtain the alloy melt. Cast the alloy melt into a mold. During the casting process, apply mechanical vibration at a frequency of 120-150Hz to the mold. After the surface of the melt solidifies, immediately place the mold into water for rapid cooling at a cooling rate ≥100℃ / s to obtain the ingot. Step 2: Hot rolling. After homogenization annealing, the ingot is hot rolled to obtain a hot-rolled strip. Step 3: Cold rolling and heat treatment. The hot-rolled strip is subjected to cold rolling, solution treatment, final cold rolling and aging treatment in sequence to obtain finished alloy plates with a thickness of 0.05-0.3mm.

2. The high-performance Cu-Ni-Co-Si alloy plate according to claim 1, characterized in that, In step one, the amount of easily burnable elements Si, Cr, Zr, and Zn added is adjusted according to the burn-off coefficient, which is: Si: 1.015-1.030, Cr: 1.005-1.015, Zr: 1.15-1.25, Zn: 1.04-1.

06.

3. The high-performance Cu-Ni-Co-Si alloy plate according to claim 1, characterized in that, In step one, the melting temperature is 1180℃-1250℃; the mold is a graphite mold, which is baked before casting.

4. The high-performance Cu-Ni-Co-Si alloy plate according to claim 1, characterized in that, In step two, the homogenization annealing temperature is 980℃-1000℃, and the holding time is adjusted according to the ingot thickness; the hot rolling heating temperature is 820℃-890℃, the final rolling temperature is 620℃-690℃, the total processing rate is 85-91%, and the pass processing rate is 20-25%.

5. The high-performance Cu-Ni-Co-Si alloy plate according to claim 1, characterized in that, In step three, the solution treatment temperature is 950℃ to 980℃, the holding time is 10-30s, and quenching is performed; the final cold rolling processing rate is 20-70%; the aging treatment temperature is 450℃-500℃, and the holding time is 4-10h.

6. The high-performance Cu-Ni-Co-Si alloy plate according to claim 5, characterized in that, The aging treatment temperature is 460℃-480℃, and the holding time is 8 hours.

7. The high-performance Cu-Ni-Co-Si alloy plate according to claim 1, characterized in that, In step three, a strip blank with a thickness of 0.3-1.2 mm is obtained after cold rolling, and then subjected to solution treatment and finally thinned to 0.05-0.3 mm by cold rolling.

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