A copper alloy material with super-high strength and high conductivity performance and a preparation method thereof

Abstract

The application discloses a copper alloy material with super-high strength and high conductivity and a preparation method thereof. The copper alloy material is composed of the following components in percentage by mass: Ni: 5-13 wt.%, Sn: 6-14 wt.%, Sn:(Ni+Sn)=40-70 wt.%, M: 0.01-0.5 wt.%, and the rest is Cu, wherein the M is at least one selected from In, Al, Cr, V, Mn and Fe. The preparation process comprises the following steps: performing multi-stage homogenization treatment on a columnar crystal ingot with the above components, obtaining a super-fine crystal structure by performing cycle 'processing-current treatment' on the homogenization-treated ingot, and performing processing-aging treatment. The copper alloy material provided by the application has super-high hardness, tensile strength and good conductivity.

Description

Technical Field

[0001] This invention relates to the field of materials design technology, and in particular to a copper alloy material with both ultra-high strength and high conductivity, and its preparation method. Background Technology

[0002] With the rapid development of modern industry, especially in high-precision industries such as computers, semiconductors, instrumentation, and information communication, high load capacity, high reliability, and long service life have become the main development directions for conductor functional devices. This makes the service conditions of alloys used in signal transmission, structural support, and thermal management systems more demanding, thus placing higher requirements on the mechanical properties of materials. Given the excellent performance of metal materials such as copper alloys, aluminum alloys, titanium alloys, and magnesium alloys in the manufacture of integrated circuit lead frames, precision electronic components, and connectors, they have become key structural functional materials in many high-tech fields.

[0003] Simultaneously improving the strength and conductivity of the alloy is one of the crucial issues that must be considered to achieve high performance in Cu-Ni-Sn alloys. Microalloying is one of the important means to improve the overall performance of alloys. Adding Fe, Co, Nb, V, Ti, Si, P, Zr, Zn, and B to Cu-Ni-Sn alloys can effectively suppress the nucleation and growth of discontinuous precipitates. For example, V can change the growth mode of precipitates, promote the precipitation of second phases, and improve the alloy's resistance to softening, thereby improving the alloy's conductivity. As a typical precipitation-strengthened alloy, the ordered phase transformation can gradually transform the modulated structure of Cu-Ni-Sn (Sn-poor, Sn-rich) into γ-DO. 22 The presence of γ-L12 ordered phases significantly improves the mechanical and electrical properties of the alloy; however, the discontinuous precipitation of γ-DO3 phases during the later stages of aging nucleates and grows at grain boundaries, severely affecting the mechanical properties of the alloy. Therefore, a high level of matching between the alloy composition and processing technology is crucial for balancing the mechanical and electrical properties of the alloy.

[0004] Current research focuses on the preparation and processing of Cu-Ni-Sn alloys, primarily examining the alloy preparation process and the addition of microalloying elements. The main technical route for preparing Cu-Ni-Sn alloys is: casting → homogenization treatment → solution treatment → cold rolling / hot rolling → aging treatment. In alloy design, domestic universities and research institutes have studied microalloying, such as adding trace amounts of Fe, Si, Nb, Al, Ti, Mn, and Zr, and the influence mechanisms of casting processes, hot and cold deformation, and aging processes on the alloy's microstructure and mechanical properties. Patent CN116287857A discloses a high-elasticity, high-strength, and high-conductivity Cu-Ni-Sn alloy and its preparation method. By adding elements such as Si, Nb, and Y (8-18% nickel, 6-10% tin, 0.1-1.0% silicon, 0.1-1.2% niobium, and 0.02-0.5% yttrium) during the alloy composition design process, the strength of the Cu-Ni-Sn alloy is improved, but the conductivity of the alloy is not affected. Patent CN106435260A discloses a high-strength, high-elasticity CuNiSn alloy material and its preparation method. This method significantly reduces the content of elements such as Ni and Sn while increasing small amounts of elements such as Co, B, V, and P (8.5-10.5% nickel, 1.8-2.8% tin, 0.5-1.0% cobalt, 0.005-0.01% boron, 0.01-0.05% vanadium, and 0.01-0.05% phosphorus). Through smelting and casting, solution annealing, milling, rough rolling, intermediate annealing, pickling, intermediate rolling, secondary solution treatment, finish rolling, and aging heat treatment, the conductivity of the alloy is slightly improved, while the hardness, strength, and other mechanical properties are slightly reduced. Patent CN118147485A discloses a high-strength, high-conductivity Cu-Ni-Sn alloy and its preparation method. This method also significantly reduces the content of elements such as Ni and Sn, and adds small amounts of elements such as Ti, Cr, and Ce (0.8–1.2% nickel, 0.8–1.0% tin, 0.3–1.0% titanium, 0.2–0.5% chromium, and 0.1–0.2% cerium), thereby improving the alloy's strength, hardness, and conductivity. However, the above methods achieve their respective goals by reducing the content of elements such as Ni and Sn or by employing multi-stage deformation heat treatment processes. Multi-stage deformation heat treatment allows solute atoms in the alloy to precipitate out as a second phase as much as possible, improving the alloy's mechanical and electrical properties. However, while the significant reduction of Ni and Sn elements is beneficial to the alloy's conductivity, it severely affects the alloy's mechanical properties. Insufficient Ni content reduces the amount of precipitated phases generated during the aging process, thus weakening the alloy's strengthening effect. Therefore, how to simultaneously improve the mutual exclusion properties of Cu-Ni-Sn alloys, such as strength and conductivity, has become the key to developing ultra-high strength and high conductivity Cu-Ni-Sn alloys. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the first objective of this invention is to provide a copper alloy material that combines ultra-high strength and high conductivity.

[0006] The second objective of this invention is to provide a method for preparing a copper alloy material that combines ultra-high strength and high conductivity. The preparation method of this invention is simple, controllable, and suitable for industrial production.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention discloses a copper alloy material that combines ultra-high strength and high conductivity. The copper alloy material has the following composition by mass percentage: Ni: 5~13wt.%, Sn: 6~14wt.%, and Sn: (Ni+Sn) = 40~70wt.%, M: 0.01~0.5wt.%, with the remainder being Cu. The M is selected from at least one of In, Al, Cr, V, Mn, and Fe, preferably In.

[0009] The copper alloy material provided by this invention forms Ni3Sn2 by adjusting the mass ratio of Ni and Sn elements. The hexagonal Ni3Sn2 precipitate reduces the number of solute atoms in the matrix, thereby improving the conductivity of the alloy. At the same time, the formed Ni3Sn2 phase particles still contribute significantly to the mechanical properties of the alloy. In addition, by adding alloying element M, some Sn atoms in the Ni3Sn2 phase are replaced, reducing the formation enthalpy of this hexagonal Ni3Sn2 phase. This allows more Ni atoms to be carried out during the aging precipitation process, thereby further purifying the matrix.

[0010] In this invention, it is crucial to control the content of each component within the scope of this invention. If the ratio of Sn:(Ni+Sn) is too small, only Ni3Sn will be formed and Ni3Sn2 compound cannot be formed. If it is too large, Ni3Sn compound cannot be formed. If M is added too little, the solute elements in the matrix cannot be fully extracted.

[0011] In a preferred embodiment, the copper alloy material has the following composition by mass percentage: Ni: 7.5~11wt.%, Sn: 8~12.5wt.%, and Sn: (Ni+Sn) = 40~60wt.%, M: 0.01~0.3wt.%, with the remainder being Cu.

[0012] In a further preferred embodiment, the copper alloy material has the following composition by mass percentage: Ni: 10~11wt.%, Sn: 10~12.5wt.%, and Sn: (Ni+Sn) = 50~55wt.%, M: 0.05~0.15wt.%, with the remainder being Cu.

[0013] In a preferred embodiment, the copper alloy material has a microstructure containing γ-DO. 22 Ordered phases, γ-L12 ordered phases, and Ni3(Sn,M)2 hexagonal structure phases. The Ni3(Sn,M)2 hexagonal structure phase is the first of its kind to be discovered in Cu-Ni-Sn alloys.

[0014] In this invention, γ-DO 22 Ordered phases and γ-L12 ordered phases can improve the mechanical properties of alloys, such as strength and hardness, while the Ni3(Sn,M)2 hexagonal structure phase can significantly improve the electrical conductivity of alloy materials, and also play a certain role in enhancing mechanical properties.

[0015] This invention discloses a method for preparing a copper alloy material with both ultra-high strength and high conductivity. The method involves taking various metal raw materials according to a designed ratio, melting them to obtain a melt, directionally solidifying the melt to obtain an ingot with a columnar crystal structure, subjecting the ingot to multi-stage homogenization treatment to obtain a homogenized billet, cyclically processing the homogenized billet A-current treatment to obtain a fine-grained billet, and then sequentially processing the fine-grained billet B-aging treatment to obtain the copper alloy material.

[0016] The preparation method of this invention first prepares columnar crystal structure by directional solidification, and then performs multi-stage homogenization treatment to eliminate dendritic segregation in the ingot; then, milling is performed to remove surface oxide scale and impurities; then, a multi-pass cycle of "machining-current treatment" is performed at room temperature to refine the grains. High-density dislocations are introduced into the ingot through machining, and current treatment is used to cause static recovery recrystallization in the high-density dislocation region of the alloy material, which greatly reduces the deformation resistance introduced by dislocation entanglement and stacking during the machining process, improves the deformation capacity of the material, and significantly increases the toughness of the material. Finally, machining-aging treatment is performed to precipitate a large number of dispersed second-phase particles in the matrix, improve the purity of the matrix, and thus improve the electrical conductivity and mechanical properties of the alloy.

[0017] The inventors discovered that columnar crystal structures exhibit significantly better deformation resistance than equiaxed crystal structures obtained through conventional smelting. Therefore, they first prepare columnar crystal ingots through directional solidification, followed by multi-stage homogenization treatment to dissolve segregated atoms and form a supersaturated solid solution. Multiple cycles of "processing-current treatment" can then refine the grains to the micrometer or even submicrometer scale, improving the alloy's performance. Finally, processing combined with aging allows solute atoms to precipitate as a second phase within the matrix, further enhancing the alloy's properties. This invention's preparation method is characterized by its short process, high efficiency, and low cost.

[0018] The preferred method involves mixing the various metal raw materials according to the design ratio and melting them at 1100~1450℃, preferably 1150~1280℃, for 5~60 minutes to obtain a melt.

[0019] In a preferred embodiment, the smelting process employs electromagnetic stirring, wherein the magnetic field strength is 2000~5000Gs and the stirring time is 1~20min during the electromagnetic stirring process.

[0020] Further optimization involves adjusting the temperature to 1150~1180℃ after smelting and holding it for 3~5 minutes, followed by applying electromagnetic stirring. During the electromagnetic stirring process, the magnetic field strength is controlled to be 2000~3500Gs and the stirring time is 5~10 minutes.

[0021] In a preferred embodiment, during directional solidification, a water-cooled copper mold is used for cooling, with a cooling water flow rate of 200~1000 L / h. In this invention, the melt is directionally solidified using a water-cooled copper mold with a cooling source at the bottom of the mold to obtain an ingot with a columnar crystal structure.

[0022] In a preferred embodiment, the multi-stage homogenization process is as follows: first, the temperature is raised to 550~700℃ and held for 0.5~4 hours, then the temperature is raised to 780~850℃ and held for 0.5~15 hours.

[0023] A further preferred embodiment of the multi-stage homogenization process is as follows: first, the temperature is raised to 620-680℃ and held for 0.5-2 hours, then raised to 780-820℃ and held for 0.5-15 hours. Through multi-stage homogenization, the segregated atoms are dissolved back to form a supersaturated solid solution. However, if only single-stage homogenization is used, the anti-segregation of Sn in the alloy cannot be uniformly eliminated, leading to cracking during subsequent cold deformation and preventing further processing.

[0024] In a preferred embodiment, during the multi-stage homogenization process, the ingot is wrapped in copper foil and its surface is covered with charcoal particles. This operation improves the multi-stage homogenization effect.

[0025] In a preferred embodiment, the homogenized billet obtained from the multi-stage homogenization process is first milled and then subjected to cold working A-current treatment in a cycle. The thickness of the milled surface is 1~3mm. Milling removes surface oxide scale and impurities.

[0026] Further preferably, the processing A is selected from one of rolling, drawing, forging, rotary forging, and radial forging, preferably rolling, and more preferably cold rolling.

[0027] In the preferred embodiment, during the homogenized billet cyclic processing of current treatment A, the deformation amount of each processing A is controlled to be 5~20%, and the cycle is repeated until the total deformation amount is 50~90%. During any single current treatment, the current is controlled to be 100~1000A; current density: 15~30A / mm². 2Frequency: 400~800Hz, duty cycle: 10~30%, temperature: 600~850℃.

[0028] In actual operation, if cold working is used, after applying current, wait for the blank to cool down before proceeding to the next processing step.

[0029] In this invention, a multi-pass cyclic "processing A-current treatment" is performed on a homogenized billet at room temperature. This involves first performing a single pass of processing A, followed by current treatment, and then repeating the process of processing A and current treatment repeatedly until the total deformation reaches 50-90%. Then, a final current treatment is applied. This process introduces high-density dislocations into the ingot through processing, and the current treatment causes recrystallization in the high-density dislocation regions of the alloy material. This significantly reduces the deformation resistance caused by dislocation entanglement and stacking during processing, improves the material's deformation capacity, and significantly increases its toughness. In addition, processing A-current treatment not only refines the grains but also increases grain boundary strengthening ability and promotes the precipitation of the second phase, further enhancing the overall performance.

[0030] The inventors discovered that current treatment is crucial for obtaining the above-mentioned properties. If the current treatment is replaced by traditional heat treatment at 600~850℃, it will result in coarse grains and fail to achieve the effect of ultra-fine grains. Of course, the process parameters of current treatment need to be effectively controlled. If the current is too high, it will lead to coarse grains or even abnormal growth, while if it is too low, recrystallization cannot be achieved.

[0031] Further optimization involves cyclically processing the homogenized billet using current treatment A, controlling the deformation amount of each processing step A to be 5-10%, repeating the cycle until the total deformation amount reaches 50-70%. During any single current treatment, the current is controlled at 300-600A; current density: 20-25A / mm². 2 Frequency: 600~800Hz, duty cycle: 20~30%, temperature: 650~800℃.

[0032] In a preferred embodiment, the deformation amount per pass of processing B is 5-15%, and the total deformation amount is 50-95%, preferably 70-95%.

[0033] In a further preferred embodiment, the processing method B is selected from one of rolling, drawing, forging, rotary forging, and radial forging, preferably rolling, and more preferably cold rolling.

[0034] In a preferred embodiment, the aging treatment temperature is 300~450℃ and the holding time is 1~240min.

[0035] By controlling the aging parameters within the above range, the second phase can be fully extracted. However, the aging temperature and aging time need to be controlled. If the aging time is too long, γ-DO...22 The ordered phase, γ-L12 ordered phase, will transform into the γ-DO3 phase (Ni3Sn), and the coarsening and growth of the Ni3(Sn,In)2 hexagonal structure phase will severely affect the alloy's properties. Insufficient aging time will further exacerbate the γ-DO3 phase. 22 The ordered phase, γ-L12 ordered phase, and Ni3(Sn,In)2 hexagonal structure phase cannot be fully analyzed, which seriously affects the electrical conductivity of the alloy.

[0036] In a further preferred embodiment, the aging treatment temperature is 325~400℃, and the holding time is 15~120min, more preferably 30~60min.

[0037] Principles and advantages

[0038] Cu-Ni-Sn alloys, as typical precipitation-strengthened alloys, can undergo ordered phase transformations that gradually convert their structure (Sn-depleted, Sn-rich) into γ-DO. 22 The presence of γ-L12 ordered phases significantly improves the mechanical and electrical properties of the alloy; however, the discontinuous γ-DO3 phase precipitates and nucleates and grows at grain boundaries during the later stages of aging, severely affecting the mechanical properties of the alloy. This invention alters the microstructure of the alloy by changing the Ni and Sn content, transforming the single Ni3Sn precipitate into a hexagonal structure of Ni3Sn and Ni3Sn2 precipitates. This maximizes the precipitation of solute atoms dissolved in the matrix. The addition of In atoms replaces some Sn atoms in Ni3Sn2, reducing the formation enthalpy of Ni3Sn2 and making the precipitates more stable, thereby improving the electrical and mechanical properties of the alloy.

[0039] Current processing technology, a novel process that can rapidly and effectively improve the microstructure and properties of materials in recent years, utilizes the electroplastic and non-electroplastic effects of electric pulses to provide instantaneous high-energy non-equilibrium input to metallic materials, significantly promoting the movement of metal atoms and vacancies. High-energy electric pulse treatment of solid metals can control the evolution of the material's microstructure and properties, including grain refinement, reduction of segregation, and alteration of microstructure morphology. In the cyclic "processing-current" treatment process, by applying a directional electric field to both ends of the processed material, the Joule heating effect is used to induce recrystallization in alloys with high-density dislocations, thereby refining the grains.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] 1) Compared with the prior art, the present invention does not rely on reducing the Ni and Sn content in the alloy (sacrificing the mechanical properties of the alloy) to improve the conductivity of the alloy. By controlling the mass ratio of Ni and Sn elements, the Ni3Sn2 phase is formed to reduce the solute atoms dissolved in the matrix, thereby improving the conductivity of the alloy. At the same time, the formed Ni3Sn2 phase particles can still make a significant contribution to the mechanical properties of the alloy. In addition, by adding alloying element M, some Sn atoms in the Ni3Sn2 phase are replaced, reducing the formation enthalpy of the hexagonal Ni3Sn2 phase. This allows more Ni and Sn atoms to be carried out during the aging precipitation process, thereby further purifying the matrix and improving the conductivity of the alloy.

[0042] 2) A graded homogenization process was used to replace traditional heat treatment, effectively shortening the homogenization time and effectively solving the problems of Sn segregation and anti-segregation in Cu-Ni-Sn alloys. Simultaneously, combining electrical pulse and cold working for blanking, and utilizing the recrystallization of high-density dislocations at low temperatures, ultrafine grains were achieved in the alloy, further improving its mechanical properties. Finally, a cold working-aging treatment was performed to precipitate dispersed second-phase particles in the copper alloy matrix, further enhancing the material's mechanical properties.

[0043] 3) This invention designs the alloy composition from the perspective of forming multiple phases and components, and then uses multi-level homogenization and cyclic "cold working + current treatment" process to eliminate segregation and achieve ultra-fine grains, resulting in an microstructure with ultra-high strength and high conductivity. This solves the problems of complex and cumbersome existing processes, high processing difficulty, high cost and low conductivity. Attached Figure Description

[0044] Figure 1 The phase type is determined by thermodynamic calculations;

[0045] Figure 2 The image shows the microstructure after multi-stage homogenization treatment in Example 1. As can be seen from the image, segregation and dendrites in the alloy have been completely eliminated, resulting in a uniform Cu matrix.

[0046] Figure 3 The image shows the microstructure after a cycle of "processing-current treatment" in Example 1; the image shows fine grains.

[0047] Figure 4 The image shows a TEM image of the Ni3(Sn,In)2 phase in Example 1. The image shows that the precipitated phase in the alloy is rich in Ni, Sn, and In elements. The energy dispersive spectroscopy (EDS) results indicate that this precipitated phase is Ni3(Sn,In)2.

[0048] Figure 5 The image shows the microstructure after single-stage homogenization treatment in Comparative Example 1. It can be seen from the image that the dendrites in the alloy were not completely eliminated and segregation exists. Detailed Implementation

[0049] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0050] Example 1

[0051] This embodiment provides a copper alloy material with both ultra-high strength and high conductivity, and its preparation method. It is smelted from the following components in the following weight ratio: Ni: 10 wt.%, Sn: 11 wt.%, In: 0.1 wt.%, with the remainder being Cu.

[0052] The preparation process is as follows:

[0053] 1) Directional melting: According to the material composition ratio, the raw materials are added to the corundum crucible in descending order of melting point. The furnace door and gas inlet are closed, the water cooling circulation system is turned on, and the water flow rate is set to 400 L / h. The mechanical pump, pre-evacuation valve, and vacuum gauge are turned on. When the atmospheric pressure inside the furnace chamber drops to 10 Pa, the high vacuum valve and the fore-stage valve are opened, and the pre-evacuation valve is closed to reduce the vacuum level inside the furnace. When the atmospheric pressure inside the chamber drops to 10 Pa... -4 When Pa is reached, the heating power is turned on, and the crucible is heated by induction using an induction coil. When the melt temperature reaches 1250℃, the temperature is lowered to 1150℃ and held for 5 minutes. At the same time, the electromagnetic stirring is turned on, the magnetic field strength is set to 3000Gs, and the stirring time is 5 minutes. Then, the mixture is poured into a water-cooled copper mold to obtain an ingot.

[0054] 2) Multi-stage homogenization treatment: The cast ingots are wrapped in copper foil, and charcoal particles are piled on the surface. They are then placed in a muffle furnace for homogenization treatment. The homogenization process is set as follows: 650℃ for 2 hours + 800℃ for 6 hours. After homogenization treatment, water quenching is performed immediately.

[0055] 3) Cyclic Cold Rolling-Current Treatment: The homogenized ingot is milled to a thickness of 2mm to remove surface oxide scale and inclusions. Due to the segregation and anti-segregation of Sn, the non-shrinkage area at the ingot head needs to be removed. Subsequently, a cyclic cold rolling-current treatment is performed at room temperature. This process uses multiple passes, with a total deformation of 70% and a single cold rolling deformation of 10%. The corresponding parameters for the current treatment are: current: 400A; current density: 22A / mm². 2 Frequency: 650Hz, Duty Cycle: 20%, Temperature: 750℃.

[0056] 4) Cold rolling aging treatment: The sample after the cyclic "cold rolling-current" treatment was cold rolled using a four-roll reversible rolling mill. The cold rolling deformation was 90%. Then it was placed in a muffle furnace for aging treatment. During the aging treatment, charcoal was added to the inside of the furnace to reduce surface oxidation. The aging temperature was 350℃ and the aging holding time was 30min.

[0057] The alloy performance indicators in this implementation case are as follows:

[0058] Hardness: 452HV

[0059] Tensile strength: 1720MPa

[0060] Conductivity: 15.34% IACS.

[0061] Example 2

[0062] This embodiment provides a copper alloy material with both ultra-high strength and high conductivity, and its preparation method. It is smelted from the following components in the following weight ratio: Ni: 10 wt.%, Sn: 11 wt.%, In: 0.1 wt.%, with the remainder being Cu.

[0063] The preparation process is as follows:

[0064] 5) Directional Melting: According to the material composition ratio, add the raw materials into the corundum crucible in descending order of melting point. Close the furnace door and gas inlet, turn on the water cooling circulation system, set the water flow rate to 400 L / h, turn on the mechanical pump, pre-evacuation valve, and vacuum gauge. When the atmospheric pressure inside the furnace chamber drops to 10 Pa, open the high vacuum valve and the fore-stage valve, and close the pre-evacuation valve to reduce the vacuum level inside the furnace. When the atmospheric pressure inside the chamber drops to 10 Pa... -4 When Pa is reached, the heating power is turned on, and the crucible is heated by induction using an induction coil. When the melt temperature reaches 1250℃, the temperature is lowered to 1150℃ and held for 5 minutes. At the same time, the electromagnetic stirring is turned on, the magnetic field strength is set to 3000Gs, and the stirring time is 5 minutes. Then, the mixture is poured into a water-cooled copper mold to obtain an ingot.

[0065] 6) Multi-stage homogenization treatment: The cast ingots are wrapped in copper foil, and charcoal particles are piled on the surface. They are then placed in a muffle furnace for homogenization treatment. The homogenization process is set as follows: 650℃ for 2 hours + 750℃ for 10 hours. After homogenization treatment, water quenching is performed immediately.

[0066] 7) Cyclic Cold Rolling-Current Treatment: The homogenized ingot is milled to a thickness of 2mm to remove surface oxide scale and inclusions. Due to the segregation and anti-segregation of Sn, the non-shrinkage area at the ingot head needs to be removed. Subsequently, a cyclic cold rolling-current treatment is performed at room temperature. This process uses multiple passes, with a total deformation of 70% and a single cold rolling deformation of 10%. The corresponding parameters for the current treatment are: current: 400A; current density: 25A / mm², frequency: 800Hz, duty cycle: 20%, temperature: 800℃.

[0067] 8) Cold rolling aging treatment: The sample after the cyclic "cold rolling-current" treatment was cold rolled using a four-roll reversible rolling mill. The cold rolling deformation was 90%. Then it was placed in a muffle furnace for aging treatment. During the aging treatment, charcoal was added to the inside of the furnace to reduce surface oxidation. The aging temperature was 350℃ and the aging holding time was 30min.

[0068] The alloy performance indicators in this implementation case are as follows:

[0069] Hardness: 438HV

[0070] Tensile strength: 1632MPa

[0071] Conductivity: 13.13% IACS.

[0072] Example 3

[0073] This embodiment provides a copper alloy material with both ultra-high strength and high conductivity, and its preparation method, which is smelted from the following components in the following weight ratio: Ni: 7.5 wt.%, Sn: 10.5 wt.%, In: 0.12 wt.%, with the remainder being Cu.

[0074] The preparation process is as follows:

[0075] 1) Directional melting: According to the material composition ratio, the raw materials are added to the corundum crucible in descending order of melting point. The furnace door and gas inlet are closed, the water cooling circulation system is turned on, and the water flow rate is set to 400 L / h. The mechanical pump, pre-evacuation valve, and vacuum gauge are turned on. When the atmospheric pressure inside the furnace chamber drops to 10 Pa, the high vacuum valve and the fore-stage valve are opened, and the pre-evacuation valve is closed to reduce the vacuum level inside the furnace. When the atmospheric pressure inside the chamber drops to 10 Pa... -4 When Pa is reached, the heating power is turned on, and the crucible is heated by induction using an induction coil. When the melt temperature reaches 1250℃, the temperature is lowered to 1150℃ and held for 5 minutes. At the same time, the electromagnetic stirring is turned on, the magnetic field strength is set to 3000Gs, and the stirring time is 5 minutes. Then, the mixture is poured into a water-cooled copper mold to obtain an ingot.

[0076] 2) Multi-stage homogenization treatment: The cast ingots are wrapped in copper foil, and charcoal particles are piled on the surface. They are then placed in a muffle furnace for homogenization treatment. The homogenization process is set as follows: 650℃ for 2 hours + 800℃ for 6 hours. After homogenization treatment, water quenching is performed immediately.

[0077] 3) Cyclic Cold Rolling-Current Treatment: The homogenized ingot is milled to a thickness of 2mm to remove surface oxide scale and inclusions. Due to the segregation and anti-segregation of Sn, the non-shrinkage area at the ingot head needs to be removed. Subsequently, a cyclic cold rolling-current treatment is performed at room temperature. This process uses multiple passes, with a total deformation of 70% and a single cold rolling deformation of 10%. The corresponding parameters for the current treatment are: current: 400A; current density: 22A / mm². 2 Frequency: 650Hz, Duty Cycle: 20%, Temperature: 750℃.

[0078] Cold rolling aging treatment: The sample after the cyclic "cold rolling-current" treatment was cold rolled using a four-roll reversible rolling mill. The cold rolling deformation was 90%. Then it was placed in a muffle furnace for aging treatment. During the aging treatment, charcoal was added to the furnace to reduce surface oxidation. The aging temperature was 350℃ and the aging holding time was 30min.

[0079] The alloy performance indicators in this implementation case are as follows:

[0080] Hardness: 424HV

[0081] Tensile strength: 1541 MPa

[0082] Conductivity: 13.88% IACS.

[0083] Example 4

[0084] This embodiment provides a copper alloy material with both ultra-high strength and high conductivity, and its preparation method, which is smelted from the following components in the following weight ratio: Ni: 5.5 wt.%, Sn: 11 wt.%, In: 0.2 wt.%, with the remainder being Cu.

[0085] The preparation process is as follows:

[0086] 1) Directional melting: According to the material composition ratio, the raw materials are added to the corundum crucible in descending order of melting point. The furnace door and gas inlet are closed, the water cooling circulation system is turned on, and the water flow rate is set to 400 L / h. The mechanical pump, pre-evacuation valve, and vacuum gauge are turned on. When the atmospheric pressure inside the furnace chamber drops to 10 Pa, the high vacuum valve and the fore-stage valve are opened, and the pre-evacuation valve is closed to reduce the vacuum level inside the furnace. When the atmospheric pressure inside the chamber drops to 10 Pa... -4At a temperature of Pa, the heating power is turned on, and the crucible is heated by induction using an induction coil. When the melt temperature reaches 1250℃, the temperature is lowered to 1150℃ and held for 5 minutes. Simultaneously, the electromagnetic stirring is turned on, and the magnetic field strength is set to 3000 Gs. After stirring for 5 minutes, the melt is immediately poured into a water-cooled copper mold to obtain an ingot.

[0087] 2) Multi-stage homogenization treatment: The cast ingots are wrapped in copper foil, and charcoal particles are piled on the surface. They are then placed in a muffle furnace for homogenization treatment. The homogenization process is set as follows: 650℃ for 2 hours + 820℃ for 6 hours. After homogenization treatment, water quenching is performed immediately.

[0088] 3) Cyclic Cold Rolling-Current Treatment: The homogenized ingot is milled to a thickness of 2mm to remove surface oxide scale and inclusions. Due to the segregation and anti-segregation of Sn, the non-shrinkage area at the ingot head needs to be removed. Subsequently, a cyclic cold rolling-current treatment is performed at room temperature. This process uses multiple passes, with a total deformation of 70% and a single cold rolling deformation of 10%. The corresponding parameters for the current treatment are: current: 400A; current density: 23A / mm². 2 Frequency: 700Hz, Duty Cycle: 20%, Temperature: 780℃.

[0089] Cold rolling aging treatment: The sample after the cyclic "cold rolling-current" treatment was cold rolled using a four-roll reversible rolling mill. The cold rolling deformation was 90%. Then it was placed in a muffle furnace for aging treatment. During the aging treatment, charcoal was added to the furnace to reduce surface oxidation. The aging temperature was 350℃ and the aging holding time was 30min.

[0090] The alloy performance indicators in this implementation case are as follows:

[0091] Hardness: 408HV

[0092] Tensile strength: 1448MPa

[0093] Conductivity: 11.45% IACS.

[0094] Comparative Example 1

[0095] This comparative example was prepared using a commercially available Cu-15Ni-8Sn alloy, which was smelted from the following components in the indicated weight ratios: Ni: 15 wt.%, Sn: 8 wt.%, with the remainder being Cu.

[0096] The preparation process is as follows:

[0097] 1) Directional melting: According to the material composition ratio, the raw materials are added to the corundum crucible in descending order of melting point. The furnace door and gas inlet are closed, the water cooling circulation system is turned on, and the water flow rate is set to 400 L / h. The mechanical pump, pre-evacuation valve, and vacuum gauge are turned on. When the atmospheric pressure inside the furnace chamber drops to 10 Pa, the high vacuum valve and the fore-stage valve are opened, and the pre-evacuation valve is closed to reduce the vacuum level inside the furnace. When the atmospheric pressure inside the chamber drops to 10 Pa... -4 When Pa is reached, turn on the heating power supply and use the induction coil to heat the crucible. When the melt temperature reaches 1250℃, lower the temperature to 1150℃ and hold for 5 minutes. At the same time, turn on the electromagnetic stirrer, set the magnetic field strength to 3000Gs, and stir for 5 minutes before casting.

[0098] 2) Multi-stage homogenization treatment: The cast ingots are wrapped in copper foil, and charcoal particles are piled on the surface. They are then placed in a muffle furnace for homogenization treatment. The homogenization process is set as follows: 650℃ for 2 hours + 800℃ for 6 hours. After homogenization treatment, water quenching is performed immediately.

[0099] 3) Cyclic Cold Rolling-Current Treatment: The homogenized ingot is milled to a thickness of 2mm to remove surface oxide scale and inclusions. Due to the segregation and anti-segregation of Sn, the non-shrinkage area at the ingot head needs to be removed. Subsequently, a cyclic cold rolling-current treatment is performed at room temperature. This process uses multiple passes, with a total deformation of 70% and a single cold rolling deformation of 10%. The corresponding parameters for the current treatment are: current: 400A; current density: 22A / mm², frequency: 650Hz, duty cycle: 20%, temperature: 750℃.

[0100] Cold rolling aging treatment: The sample after the cyclic "cold rolling-current" treatment was cold rolled using a four-roll reversible rolling mill. The cold rolling deformation was 90%. Then it was placed in a muffle furnace for aging treatment. During the aging treatment, charcoal was added to the furnace to reduce surface oxidation. The aging temperature was 350℃ and the aging holding time was 30min.

[0101] The alloy performance indicators in this implementation case are as follows:

[0102] Hardness: 401HV

[0103] Tensile strength: 1367MPa

[0104] Conductivity: 8.78% IACS.

[0105] Comparative Example 2

[0106] This comparative example uses a traditional single-stage homogenization process to prepare the alloy, which is smelted from the following components in the indicated weight ratios: Ni: 10 wt.%, Sn: 11 wt.%, In: 0.1 wt.%, with the remainder being Cu.

[0107] The preparation process is as follows:

[0108] 1) Directional melting: According to the material composition ratio, the raw materials are added to the corundum crucible in descending order of melting point. The furnace door and gas inlet are closed, the water cooling circulation system is turned on, and the water flow rate is set to 400 L / h. The mechanical pump, pre-evacuation valve, and vacuum gauge are turned on. When the atmospheric pressure inside the furnace chamber drops to 10 Pa, the high vacuum valve and the fore-stage valve are opened, and the pre-evacuation valve is closed to reduce the vacuum level inside the furnace. When the atmospheric pressure inside the chamber drops to 10 Pa... -4 When Pa is reached, turn on the heating power supply and use the induction coil to heat the crucible. When the melt temperature reaches 1250℃, lower the temperature to 1150℃ and hold for 5 minutes. At the same time, turn on the electromagnetic stirrer, set the magnetic field strength to 3000Gs, and stir for 5 minutes before casting.

[0109] 2) Traditional homogenization treatment: The cast ingot is wrapped in copper foil, and charcoal particles are piled on the surface. It is then placed in a muffle furnace for homogenization treatment, with the homogenization process set at 800℃ for 15 hours. After homogenization treatment, it is immediately subjected to water quenching.

[0110] 3) Cyclic Cold Rolling-Current Treatment: The homogenized ingot is milled to a thickness of 2mm to remove surface oxide scale and inclusions. Due to the segregation and anti-segregation of Sn, the non-shrinkage area at the ingot head needs to be removed. Subsequently, a cyclic cold rolling-current treatment is performed at room temperature. This process uses multiple passes, with a total deformation of 70% and a single cold rolling deformation of 10%. The corresponding parameters for the current treatment are: current: 400A; current density: 22A / mm², frequency: 650Hz, duty cycle: 20%, temperature: 750℃.

[0111] 4) Cold rolling aging treatment: The sample after the cyclic "cold rolling-current" treatment was cold rolled using a four-roll reversible rolling mill. The cold rolling deformation was 90%. Then it was placed in a muffle furnace for aging treatment. During the aging treatment, charcoal was added to the inside of the furnace to reduce surface oxidation. The aging temperature was 350℃ and the aging holding time was 30min.

[0112] The alloy performance indicators in this implementation case are as follows:

[0113] Hardness: 422HV

[0114] Tensile strength: 1545MPa

[0115] Conductivity: 13.44% IACS.

[0116] Comparative Example 3

[0117] This comparative example demonstrates alloy preparation using a non-cyclic "cold rolling-current" process, where the alloy is smelted from the following components in the indicated weight ratios: Ni: 10 wt.%, Sn: 11 wt.%, In: 0.1 wt.%, with the remainder being Cu.

[0118] The preparation process is as follows:

[0119] 1) Directional melting: According to the material composition ratio, the raw materials are added to the corundum crucible in descending order of melting point. The furnace door and gas inlet are closed, the water cooling circulation system is turned on, and the water flow rate is set to 400 L / h. The mechanical pump, pre-evacuation valve, and vacuum gauge are turned on. When the atmospheric pressure inside the furnace chamber drops to 10 Pa, the high vacuum valve and the fore-stage valve are opened, and the pre-evacuation valve is closed to reduce the vacuum level inside the furnace. When the atmospheric pressure inside the chamber drops to 10 Pa... -4 When Pa is reached, turn on the heating power supply and use the induction coil to heat the crucible. When the melt temperature reaches 1250℃, lower the temperature to 1150℃ and hold for 5 minutes. At the same time, turn on the electromagnetic stirrer, set the magnetic field strength to 3000Gs, and stir for 5 minutes before casting.

[0120] 2) Multi-stage homogenization treatment: The cast ingots are wrapped in copper foil, and charcoal particles are piled on the surface. They are then placed in a muffle furnace for homogenization treatment, with the process set as follows: 650℃ for 2 hours + 800℃ for 6 hours. Water quenching is performed immediately after homogenization.

[0121] 3) Cold rolling aging treatment: The sample after the "cold rolling-current" treatment was cold rolled using a four-roll reversible rolling mill. The cold rolling deformation was 90%. Then it was placed in a muffle furnace for aging treatment. During the aging treatment, charcoal was added to the inside of the furnace to reduce surface oxidation. The aging temperature was 350℃ and the aging holding time was 30min.

[0122] The alloy performance indicators in this implementation case are as follows:

[0123] Hardness: 424HV

[0124] Tensile strength: 1485MPa

[0125] Conductivity: 12.75% IACS.

Claims

1. A method for preparing a copper alloy material possessing both ultra-high strength and high electrical conductivity, characterized in that: According to the design ratio, each metal raw material is selected, smelted to obtain a melt, the melt is directionally solidified to obtain an ingot with columnar crystal structure, the ingot is subjected to multi-stage homogenization treatment to obtain a homogenized billet, the homogenized billet is cyclically processed A-current treatment to obtain a fine-grained billet, and the fine-grained billet is then processed B and aged in sequence to obtain copper alloy material. When homogenizing the billet and performing A-current processing, control the deformation amount of each processing step A to 5-20%, repeating until the total deformation amount reaches 50-90%. During any single current processing step, control the current to 100-1000A; current density: 15-30A / mm². 2 Frequency: 400~800Hz, duty cycle: 10~30%, temperature: 600~850℃; The A-current processing involves first performing a single-pass A-processing, followed by applying current processing. The copper alloy material, by mass percentage, has the following composition: Ni: 5~13wt.%, Sn: 6~14wt.%, and Sn: (Ni+Sn) = 40~70wt.%, M: 0.01~0.5wt.%, with the remainder being Cu, wherein M is selected from at least one of In, Al, Cr, V, Mn, and Fe; The microstructure of the copper alloy material contains γ-DO. 22 Ordered phase, γ-L12 ordered phase, Ni3(Sn,M)2 hexagonal structure phase.

2. The method for preparing a copper alloy material with both ultra-high strength and high conductivity according to claim 1, characterized in that: According to the design ratio, the various metal raw materials are prepared and smelted at 1100~1450℃ to obtain a melt. The smelting time is 1~20 minutes, and the vacuum degree is controlled at 10 during the smelting process. -5 ~10 -3 Pa; The smelting process employs electromagnetic stirring. During the electromagnetic stirring process, the magnetic field strength is 2000~5000Gs, and the stirring time is 1~20min.

3. The method for preparing a copper alloy material with both ultra-high strength and high conductivity according to claim 1, characterized in that: During the directional solidification process, a water-cooled copper mold is used for cooling, with a cooling water flow rate of 200~1000L / h.

4. The method for preparing a copper alloy material with both ultra-high strength and high conductivity according to claim 1, characterized in that: The multi-stage homogenization process is as follows: first, heat to 550~700℃ and hold for 0.5~4h, then heat to 780~850℃ and hold for 0.5~15h. During the multi-stage homogenization process, the ingot is wrapped with copper foil and charcoal particles are piled on its surface.

5. The method for preparing a copper alloy material with both ultra-high strength and high conductivity according to claim 1, characterized in that: The homogenized blank obtained from the multi-stage homogenization process is first milled and then cyclically processed with A-current treatment. The thickness of the milled surface is 1~3mm.

6. The method for preparing a copper alloy material with both ultra-high strength and high conductivity according to claim 1, characterized in that: The deformation amount per pass in processing B is 5-15%, and the total deformation amount is 50-95%. The aging treatment temperature is 300~450℃, and the holding time is 1~240min.

7. The method for preparing a copper alloy material with both ultra-high strength and high conductivity according to claim 1, characterized in that: The copper alloy material, by mass percentage, has the following composition: Ni: 7.5~11wt.%, Sn: 8~12.5wt.%, and Sn: (Ni+Sn) = 40~60wt.%, M: 0.01~0.3wt.%, with the remainder being Cu.

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