High-strength and high-conductivity CuCrSn alloy and preparation method thereof

Abstract

The application provides a high-strength and high-conductivity CuCrSn alloy and a preparation method thereof, and belongs to the technical field of copper alloys. The preparation method comprises the following steps: firstly, homogenizing treatment and hot rolling treatment are performed on a CuCrSn alloy ingot to obtain a hot-rolled blank; then, solid solution treatment is performed on the hot-rolled blank to obtain a supersaturated solid solution state blank; subsequently, first cold rolling deformation is performed on the supersaturated solid solution state blank to obtain a first cold-rolled blank; then, intermediate aging treatment is performed on the first cold-rolled blank to make Cr elements dissolved in a Cu matrix precipitate to obtain an intermediate aging blank; finally, second cold rolling deformation is performed on the intermediate aging blank to obtain the high-strength and high-conductivity CuCrSn alloy. Through regulation and control of the solid solution, rolling and aging treatment process of the CuCrSn alloy, the internal organizational structure of the alloy is improved, the Cr elements fully participate in the formation of a strengthening phase, the strength of the alloy is improved while the high conductivity is maintained, and the CuCrSn alloy with high strength and high conductivity is obtained.

Description

Technical Field

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

[0002] Copper and copper alloys possess excellent electrical conductivity and machinability, making them widely used in power transmission, electronic connectors, and conductive structural components. However, with increasing demands for load-bearing capacity in these components, traditional pure copper, due to its relatively low strength, struggles to meet structural support requirements in certain applications. Therefore, improving the mechanical properties of copper while maintaining its electrical conductivity has become a crucial research direction for copper alloys. Among these, Cu-Cr copper alloys, which utilize the solid solution and precipitation of Cr in the copper matrix to create a strengthening effect, have attracted considerable attention by maintaining a certain level of electrical conductivity while improving material strength.

[0003] Existing CuCrZr-based copper alloys utilize Cr and Zr elements for alloying, and heat treatment promotes the formation of strengthening phases to improve material properties. However, Zr in CuCrZr alloys has high chemical reactivity and is prone to oxidation and burn-off during smelting, increasing the difficulty of controlling alloy composition and placing higher demands on smelting equipment and process conditions. Furthermore, the Cu-Zr binary system exhibits a low-temperature eutectic reaction (Cu+Cu5Zr) at approximately 960℃ in the Cu-rich region, making it difficult to use higher temperatures for solution treatment of traditional CuCrZr alloys. This limits the degree of Cr solubility in the Cu matrix, affecting the formation of Cr-rich precipitates and their strengthening effect during aging.

[0004] To address the aforementioned issues, some studies have proposed using Sn to replace Zr in the formation of CuCrSn alloys to reduce the influence of Zr on the alloy preparation process. However, existing studies still primarily employ the solution treatment conditions for CuCrZr alloys, typically using a solution temperature of 940–960 °C, which limits the degree of Cr solubility in the Cu matrix.

[0005] Furthermore, existing deformation heat treatment of CuCr-based copper alloys typically employs a multi-stage process involving solution treatment, single cold rolling, intermediate aging, secondary cold rolling, and low-temperature final aging to promote the formation of strengthening phases. However, this process involves numerous steps, increasing material handling time and energy consumption. On the other hand, if a single large deformation cold rolling combined with single aging is used, the high density of dislocation structures generated during cold rolling can lead to dislocation pile-up, affecting the diffusion and precipitation of Cr.

[0006] Therefore, there is an urgent need for a method to prepare CuCrSn alloys, which can improve the internal microstructure of the alloy by adjusting the solution treatment, rolling deformation and aging treatment processes, so that the prepared CuCrSn alloys can meet the requirements for strength and electrical conductivity. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, the purpose of this invention is to provide a high-strength and high-conductivity CuCrSn alloy and its preparation method. By controlling the solid solution, rolling and aging processes of the CuCrSn alloy, the internal microstructure of the alloy is improved, so that the Cr element can fully participate in the formation of the strengthening phase. While maintaining high conductivity, the alloy strength is improved, and a CuCrSn alloy with high strength and high conductivity is obtained.

[0008] To achieve the above objectives, the present invention provides the following solution: On one hand, the present invention provides a method for preparing a high-strength, high-conductivity CuCrSn alloy, comprising the following steps: S1. The CuCrSn alloy ingot is homogenized and hot-rolled to obtain a hot-rolled billet. S2. The hot-rolled billet is subjected to solution treatment to obtain a supersaturated solution-treated billet. S3. Perform a first cold rolling deformation on the supersaturated solid solution billet to obtain a first cold-rolled billet; S4. The first cold-rolled billet is subjected to intermediate aging treatment to precipitate the Cr element dissolved in the Cu matrix and obtain an intermediate-aged billet. S5. Perform a second cold rolling deformation on the intermediate aging billet to obtain a high-strength, high-conductivity CuCrSn alloy.

[0009] Preferably, in step S1, the homogenization treatment temperature is 940~980℃, and the holding time is 4~6h.

[0010] Preferably, in step S1, the temperature of the hot rolling treatment is 900~940℃, and the total hot rolling reduction is not less than 50%.

[0011] Preferably, in step S2, the solution treatment temperature is 1000~1040℃, and the holding time is 60~90min.

[0012] Preferably, the billet after solution treatment is cooled by water quenching at a rate of not less than 120°C / s, so that the Cr element after solution treatment remains in the Cu matrix to form a supersaturated solid solution state.

[0013] Preferably, in step S3, the deformation amount of the first cold rolling deformation is 60~70%.

[0014] Preferably, in step S4, the intermediate aging treatment temperature is 450~500℃, and the holding time is 1~2h.

[0015] Preferably, in step S5, the deformation amount of the second cold rolling deformation is 20-30%.

[0016] On the other hand, the present invention provides a high-strength, high-conductivity CuCrSn alloy prepared according to the above preparation method, wherein the high-strength, high-conductivity CuCrSn alloy comprises, by weight percentage: Cr: 0.6~0.9wt% Sn: 0.1~0.3wt% The balance is Cu.

[0017] Preferably, the high-strength, high-conductivity CuCrSn alloy has a tensile strength of not less than 600 MPa and an electrical conductivity of not less than 70% IACS.

[0018] Compared with the prior art, the present invention discloses at least the following technical effects: (1) This invention uses CuCrSn alloy composition design and improves the solubility of Cr in the Cu matrix by high-temperature solution treatment at 1000~1040℃, so that the alloy after solution treatment obtains a high Cr supersaturation state, providing an elemental basis for the formation of Cr-rich precipitates during aging. Compared with the existing CuCrZr alloy, which usually uses solution treatment at 940~960℃, this invention improves the distribution of Cr in the copper matrix by increasing the solution treatment temperature, which is conducive to the formation of Cr-rich precipitates with strengthening effect.

[0019] (2) This invention employs a staged deformation heat treatment process consisting of a first cold rolling, intermediate aging, and a second cold rolling, enabling the solid solution alloy to form a microstructure combining Cr-rich precipitates and deformation substructures during deformation and aging. Specifically, the intermediate aging process promotes the precipitation of Cr elements from the supersaturated solid solution, forming a dispersed strengthening phase; the staged rolling process regulates the evolution of the deformation microstructure, reducing dislocation concentration caused by a single large deformation, allowing the Cr-rich precipitates and dislocation structures to jointly enhance their resistance to dislocation movement, thereby improving the mechanical properties of the alloy.

[0020] (3) This invention combines high-temperature solution treatment with intermediate aging, enabling Cr to fully participate in the precipitation strengthening process. After the second cold rolling deformation, no additional final aging treatment is required to obtain a high-strength, high-conductivity CuCrSn alloy that meets the application requirements. Compared to the traditional multi-stage process of solution treatment, cold rolling, intermediate aging, secondary cold rolling, and final aging, this invention reduces the final aging step, shortens the processing flow, reduces energy consumption during heat treatment, and avoids the negative impact of microstructure recovery that may occur during secondary aging on the alloy's strength.

[0021] (4) The high-strength and high-conductivity CuCrSn alloy prepared by the present invention has high strength and conductivity. The tensile strength of the high-strength and high-conductivity CuCrSn alloy is not less than 600 MPa and the conductivity is not less than 70% IACS. At the same time, through the above composition design and preparation method, the internal structure of the alloy is kept stable, which meets the use requirements of conductive structural components such as integrated circuit lead frames, new energy conductive connectors and high-power electrical contacts. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in 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.

[0023] Figure 1 This is a flowchart of a method for preparing a high-strength, high-conductivity CuCrSn alloy according to the present invention.

[0024] Figure 2 This is a microstructure image of the supersaturated solution-treated CuCrSn alloy sheet obtained after solution treatment in Example 3 of the present invention.

[0025] Figure 3 This is a microstructure image of the CuCrSn alloy in the as-cast state in Example 4 of the present invention.

[0026] Figure 4 This is a stress-strain curve of the CuCrSn alloy plate in Example 4 of the present invention.

[0027] Figure 5 This is a tensile fracture morphology diagram of the CuCrSn alloy plate in Example 4 of the present invention. Detailed Implementation

[0028] 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.

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1 As shown, this invention provides a method for preparing a high-strength, high-conductivity CuCrSn alloy, comprising the following steps: S1. The CuCrSn alloy ingot is homogenized and hot-rolled to obtain a hot-rolled billet.

[0031] Specifically, Cu, Cr, and Sn elements are proportioned according to a set ratio and then smelted to prepare CuCrSn alloy ingots. The CuCrSn alloy, by weight percentage, comprises: Cr: 0.6~0.9wt% Sn: 0.1~0.3wt% The balance is Cu.

[0032] By controlling the Cr element content to be higher than the Sn element content, Cr element is made to participate in the solid solution and precipitation process as the main strengthening element, thus providing the elemental basis for the formation of the Cr strengthening phase.

[0033] The prepared CuCrSn alloy ingots were subjected to homogenization treatment at a temperature of 940–980℃ for 4–6 hours. This homogenization treatment improved the elemental segregation that occurred during casting, reducing the impact of uneven Cr and Sn distribution in the as-cast microstructure on subsequent processing.

[0034] After homogenization, the alloy ingot is hot-rolled at a temperature of 900-940℃, with a total reduction of not less than 50%. Through hot rolling deformation, the coarse dendritic structure in the as-cast microstructure is broken up, while the density of the billet is increased, internal casting defects are reduced, and a hot-rolled billet with a microstructure suitable for solution treatment is obtained.

[0035] S2. The hot-rolled billet is subjected to solution treatment to obtain a supersaturated solution-treated billet.

[0036] Specifically, the hot-rolled billet is subjected to solution treatment at a temperature of 1000~1040℃ and a holding time of 60~90min.

[0037] This invention employs a high-temperature solution treatment method close to the Cu-Cr eutectic temperature range. Compared to the traditional CuCrZr alloy, which typically undergoes solution treatment at 940~960℃, this application increases the solution treatment temperature to provide more sufficient conditions for the diffusion of Cr elements in the Cu matrix, allowing more Cr elements to enter the Cu matrix to form a solid solution state, thereby increasing the Cr content in the solid solution matrix and obtaining a solution-treated billet with a higher degree of supersaturation.

[0038] After solution treatment, the billet is water-quenched at a rate of not less than 120℃ / s. By rapidly reducing the billet temperature, the premature precipitation of Cr during the cooling process is reduced, allowing the Cr in the solution state to remain in the Cu matrix, forming a supersaturated solution state, which provides a sufficient source for the precipitation of Cr during intermediate aging.

[0039] S3. The supersaturated solid solution billet is subjected to a first cold rolling deformation to obtain a first cold-rolled billet.

[0040] Specifically, the supersaturated solid solution billet is subjected to a first cold rolling deformation, with the deformation amount being 60-70%.

[0041] The first cold rolling deformation induces plastic deformation within the material, introducing a uniformly distributed deformation energy storage and a high-density dislocation structure, providing nucleation sites for the diffusion and precipitation of Cr during intermediate aging. Simultaneously, by controlling the amount of deformation in the first cold rolling, excessive concentration of dislocation structures during a single large deformation is avoided, resulting in a more uniform dislocation distribution and providing an organizational basis for precipitate formation.

[0042] S4. The first cold-rolled billet is subjected to intermediate aging treatment to precipitate the Cr element dissolved in the Cu matrix, thereby obtaining an intermediate-aged billet.

[0043] Specifically, the first cold-rolled billet undergoes intermediate aging treatment at a temperature of 450~500℃ for 1~2 hours.

[0044] During intermediate aging, supersaturated Cr atoms dissolved in the Cu matrix diffuse and gradually precipitate, forming a diffusely distributed Cr-rich precipitate phase in the matrix. Since the dislocation structures formed during the first cold rolling process provide nucleation sites for the precipitates, this promotes the formation of the Cr-rich precipitate phase and improves its distribution within the Cu matrix. Simultaneously, the formation of the Cr-rich precipitate phase reduces the residual dissolved Cr content in the Cu matrix, diminishes the influence of dissolved elements on electron transport, and enhances the material's strengthening effect by hindering dislocation movement.

[0045] S5. Perform a second cold rolling deformation on the intermediate aging billet to obtain a high-strength, high-conductivity CuCrSn alloy.

[0046] Specifically, the intermediate aging billet undergoes a second cold rolling deformation, with the deformation amount being 20-30%.

[0047] The second cold rolling deformation further forms a deformable structure inside the material, allowing the Cr-rich precipitates formed during the intermediate aging process to interact with the dislocation structure.

[0048] Among them, the Cr-rich precipitates can hinder dislocation movement and improve the material's resistance to plastic deformation; at the same time, the deformation structure formed by the second cold rolling can further improve the material's strength, so that precipitation strengthening and deformation strengthening work together. Compared with the single large deformation cold rolling process, this invention adopts a preparation process that combines the first cold rolling, intermediate aging and the second cold rolling, so that the deformation process is carried out in stages, reducing the microstructure inhomogeneity caused by a large amount of dislocation pile-up and improving the internal microstructure stability of the alloy.

[0049] The high-strength, high-conductivity CuCrSn alloy prepared by the above method has a tensile strength of not less than 600 MPa, an electrical conductivity of not less than 70% IACS, and a strength-ductility product of 7.5~9.0 GPa·%, which can meet the requirements for the use of high-strength conductive structural materials.

[0050] The above content will be further described below through specific implementation methods.

[0051] Example 1 This embodiment provides a method for preparing a high-strength, high-conductivity CuCrSn alloy, specifically including the following steps: According to the target composition, high-purity copper, pure Sn, and Cu-10Cr master alloy were selected as raw materials. The CuCrSn alloy contained 0.64wt% Cr, 0.23wt% Sn, and the balance Cu. The above raw materials were placed in a graphite crucible and vacuum induction melting was carried out under argon protection. The temperature was heated to 1200~1300℃ to fully melt the raw materials. After holding at the temperature, the mixture was cast into CuCrSn alloy ingots.

[0052] The obtained CuCrSn alloy ingot was homogenized at 940℃ for 6 hours to improve elemental segregation in the as-cast microstructure. After homogenization, it was hot-rolled at 900℃ with a total reduction of 50% to obtain a hot-rolled slab.

[0053] The hot-rolled slab is subjected to solution treatment at a heating temperature of 1000℃ and a holding time of 1h, so that the Cr element is fully dissolved in the Cu matrix. After the solution treatment is completed, it is cooled by water quenching at a cooling rate of not less than 120℃ / s to obtain a supersaturated solution-treated slab.

[0054] Subsequently, the solution-treated sheet was subjected to a first cold rolling deformation of 60% to obtain the first cold-rolled billet. The first cold-rolled billet was then subjected to intermediate aging treatment at a temperature of 450℃ and a holding time of 2 hours, which caused the supersaturated Cr element dissolved in the Cu matrix to diffuse and precipitate, forming a precipitated strengthening phase.

[0055] The plate after intermediate aging is subjected to a second cold rolling deformation with a deformation amount of 30% to obtain the final CuCrSn alloy plate.

[0056] Performance tests showed that the CuCrSn alloy plate had a tensile strength of 601.8 MPa, an electrical conductivity of 75.1% IACS, and a strength-ductility product of 8.89 GPa·s.

[0057] Example 2 This embodiment provides a method for preparing a high-strength, high-conductivity CuCrSn alloy, the specific steps of which are as follows: According to the target composition, high-purity copper, pure Sn, and Cu-10Cr master alloy are selected as smelting raw materials, placed in a graphite crucible and transferred to a vacuum induction melting furnace. Smelting is carried out under argon protection. The temperature is heated to 1200~1300℃ to fully melt all the raw materials. After holding at the temperature, the mixture is cast into a mold to obtain CuCrSn alloy ingot.

[0058] Testing revealed that the as-cast CuCrSn alloy contained 0.78 wt% Cr, 0.17 wt% Sn, and the balance was Cu.

[0059] The obtained CuCrSn alloy ingot was subjected to homogenization treatment at a temperature of 960℃ for 4 hours to improve element segregation in the as-cast structure and make the distribution of Cr and Sn elements in the Cu matrix more uniform.

[0060] After homogenization, the alloy ingot is hot-rolled at 940℃ with a total reduction of 55% to obtain a hot-rolled slab. Hot rolling deformation breaks down the coarse dendritic structure in the as-cast microstructure, improving the density of the slab.

[0061] The hot-rolled slab is subjected to solution treatment at a heating temperature of 1000℃ and a holding time of 1.5h to allow Cr to be fully dissolved in the Cu matrix. After the solution treatment is completed, it is rapidly cooled by water quenching at a cooling rate of not less than 120℃ / s to obtain a supersaturated solution-treated slab.

[0062] Subsequently, the supersaturated solution-treated sheet was subjected to a first cold rolling deformation of 65% to obtain a first cold-rolled billet. The first cold-rolled billet was then subjected to intermediate aging treatment at a temperature of 480°C and a holding time of 2 hours, which caused the Cr element dissolved in the Cu matrix to diffuse and precipitate, forming a strengthening phase.

[0063] After intermediate aging, the sheet is subjected to a second cold rolling deformation, with a cold rolling deformation amount of 25%, to obtain the final CuCrSn alloy sheet.

[0064] Performance tests showed that the CuCrSn alloy plate had a tensile strength of 624.8 MPa, an electrical conductivity of 74.3% IACS, and a strength-ductility product of 8.47 GPa·s.

[0065] Example 3 This embodiment provides a method for preparing a high-strength, high-conductivity CuCrSn alloy, the specific steps of which are as follows: According to the target composition, high-purity copper, pure Sn, and Cu-10Cr master alloy are selected as smelting raw materials, placed in a graphite crucible and transferred to a vacuum induction melting furnace. Smelting is carried out under argon protection. The temperature is heated to 1200~1300℃ to fully melt all the raw materials. After holding at the temperature, the mixture is cast into a mold to obtain CuCrSn alloy ingot.

[0066] Testing revealed that the as-cast CuCrSn alloy contained 0.80 wt% Cr, 0.20 wt% Sn, and the balance was Cu.

[0067] The CuCrSn alloy ingot was subjected to homogenization treatment at a temperature of 980℃ for 4 hours to improve element segregation in the as-cast structure.

[0068] After homogenization, the alloy ingot is hot-rolled at a temperature of 900℃ with a total reduction of 50% to obtain a hot-rolled slab.

[0069] The obtained hot-rolled slab is subjected to solution treatment at a temperature of 1020℃ and a holding time of 1h, so that Cr element enters the Cu matrix to form a supersaturated solution state. After solution treatment, water quenching is performed at a cooling rate of not less than 120℃ / s to obtain a supersaturated solution slab.

[0070] Microscopic observation of the supersaturated solid solution sheet material revealed the following morphology: Figure 2 As shown. By Figure 2 It can be seen that after high-temperature solution treatment at 1020℃ and rapid water quenching, the CuCrSn alloy exhibits a relatively uniform matrix structure. No obvious continuous distribution of coarse second-phase structure was observed, indicating that the solution treatment can promote the entry of Cr elements into the Cu matrix and reduce the segregation effect left by the as-cast structure, so that the alloy can obtain a relatively stable supersaturated solution state, providing a microstructure basis for the diffusion and precipitation of Cr elements during intermediate aging.

[0071] Subsequently, the solution-treated sheet was subjected to a first cold rolling deformation, with a cold rolling deformation amount of 60%, to obtain the first cold-rolled billet.

[0072] The first cold-rolled billet is subjected to intermediate aging treatment at a temperature of 500℃ and a holding time of 2h, which causes the Cr element in the supersaturated Cu matrix to diffuse and precipitate, forming a Cr-rich precipitate phase.

[0073] After intermediate aging, the sheet is subjected to a second cold rolling deformation, with a cold rolling deformation amount of 30%, to obtain the final CuCrSn alloy sheet.

[0074] Performance tests showed that the CuCrSn alloy plate had a tensile strength of 636.4 MPa, an electrical conductivity of 73.6% IACS, and a strength-ductility product of 8.23 ​​GPa·s.

[0075] Example 4 This embodiment provides a method for preparing a high-strength, high-conductivity CuCrSn alloy, the specific steps of which are as follows: According to the target composition, high-purity copper, pure Sn, and Cu-10Cr master alloy are selected as smelting raw materials, placed in a graphite crucible and transferred to a vacuum induction melting furnace. Smelting is carried out under argon protection. The temperature is heated to 1200~1300℃ to fully melt all the raw materials. After holding at the temperature, the mixture is cast into a mold to obtain CuCrSn alloy ingot.

[0076] Testing revealed that the as-cast CuCrSn alloy contained 0.86 wt% Cr, 0.16 wt% Sn, and the balance was Cu. Its as-cast microstructure is as follows: Figure 3 As shown. By Figure 3 It can be seen that the microstructure of the as-cast CuCrSn alloy exhibits typical casting microstructure characteristics, with relatively obvious grain boundary distribution and microstructural differences formed by the solidification process observed in the matrix. Due to insufficient diffusion of alloying elements during casting, there may be regions with uneven element distribution in the as-cast microstructure. Therefore, homogenization treatment to promote the diffusion of Cr and Sn elements in the Cu matrix is ​​beneficial to improving the as-cast microstructure and providing a uniform microstructure basis for hot rolling deformation and solution treatment.

[0077] The obtained CuCrSn alloy ingot was then subjected to homogenization treatment at a temperature of 960℃ for 6 hours.

[0078] After homogenization, the alloy ingot is hot-rolled at a temperature of 940℃ with a total reduction of 60% to obtain a hot-rolled slab.

[0079] The hot-rolled slab is subjected to solution treatment at a temperature of 1040℃ for 1.5 hours. After the solution treatment, it is cooled by water quenching at a rate of not less than 120℃ / s to obtain a supersaturated solution-treated slab.

[0080] Subsequently, the solution-treated sheet was subjected to a first cold rolling deformation, with a cold rolling deformation amount of 60%.

[0081] The first cold-rolled billet was subjected to intermediate aging treatment at a temperature of 500℃ for 2 hours.

[0082] After intermediate aging, the sheet is subjected to a second cold rolling deformation, with a cold rolling deformation amount of 30%, to obtain the final CuCrSn alloy sheet.

[0083] After preparing the CuCrSn alloy sheet using the above method, its room temperature tensile properties were tested, and the stress-strain curves are shown below. Figure 4 As shown. By Figure 4 It can be seen that the prepared CuCrSn alloy plate has a continuous plastic deformation stage during the tensile process, and can still maintain a certain degree of deformation capacity after reaching the maximum tensile stress, indicating that the alloy has good plasticity while obtaining high strength.

[0084] Depend on Figure 5 It can be seen that the tensile fracture region exhibits relatively obvious ductile fracture characteristics, with a large number of fine dimple structures distributed on the fracture surface. No obvious flat cleavage fracture regions were observed, indicating that the material can undergo a certain degree of plastic deformation and crack propagation inhibition during the tensile process. This fracture morphology shows that the high-temperature solution treatment, staged cold rolling, and intermediate aging treatment adopted in this embodiment form a relatively stable strengthening structure inside the alloy, improving the material strength while maintaining good plastic deformation capacity.

[0085] Further testing revealed that the CuCrSn alloy plate had a tensile strength of 644.4 MPa, an electrical conductivity of 71.8% IACS, and a strength-ductility product of 7.91 GPa·s.

[0086] Comparative Example 1 The steps for this comparative example are as follows: CuCrSn alloy ingots were prepared in the same manner as in Example 1, wherein the Cr content was 0.64 wt% and the Sn content was 0.23 wt%.

[0087] The alloy ingot was homogenized at 940℃ for 6 hours and then hot-rolled at 900℃ with a total hot rolling reduction of 50% to obtain a hot-rolled slab.

[0088] Unlike Example 1, this comparative example adjusted the solution treatment temperature to 960°C and the holding time to 1 hour. After solution treatment, the solution was cooled by water quenching, followed by a 60% first cold rolling deformation, an intermediate aging treatment at 450°C for 2 hours, and a 30% second cold rolling deformation.

[0089] Performance tests showed that the CuCrSn alloy plate had a tensile strength of 578.4 MPa, an electrical conductivity of 70.9% IACS, and a strength-ductility product of 7.49 GPa·s.

[0090] Comparative Example 2 The steps for this comparative example are as follows: CuCrSn alloy ingots were prepared in the same manner as in Example 2, wherein the Cr content was 0.78 wt% and the Sn content was 0.17 wt%.

[0091] The alloy ingot was homogenized at 960℃ for 4 hours and then hot-rolled at 940℃ with a total hot rolling reduction of 55% to obtain a hot-rolled slab.

[0092] The hot-rolled slab was solution treated at 1000℃ for 1.5 hours and then water-quenched.

[0093] Unlike Example 2, this comparative example omits the phased processing method of first cold rolling, intermediate aging and second cold rolling, and directly performs 90% single cold rolling deformation and aging treatment at 480°C for 2 hours.

[0094] Performance tests showed that the CuCrSn alloy sheet had a tensile strength of 530.9 MPa, an electrical conductivity of 69.2% IACS, and a strength-ductility product of 6.93 GPa·s.

[0095] Comparative Example 3 The steps for this comparative example are as follows: CuCrSn alloy ingots were prepared in the same manner as in Example 3, wherein the Cr content was 0.80 wt% and the Sn content was 0.20 wt%.

[0096] The alloy ingot was homogenized at 980℃ for 4 hours, hot rolled at 900℃, and solution treated at 1020℃ for 1 hour before being water quenched.

[0097] Then, a first cold rolling deformation of 60% is carried out.

[0098] Unlike Example 3, this comparative example adjusts the intermediate aging temperature to 400°C, the holding time remains 2 hours, and then performs a second cold rolling deformation of 30%.

[0099] Performance tests showed that the CuCrSn alloy plate had a tensile strength of 565.7 MPa, an electrical conductivity of 72.6% IACS, and a strength-ductility product of 7.33 GPa·s.

[0100] Comparative Example 4 The steps for this comparative example are as follows: CuCrSn alloy ingots were prepared in the same manner as in Example 4, wherein the Cr content was 0.86 wt% and the Sn content was 0.16 wt%.

[0101] The alloy ingot was homogenized at 960℃ for 6 hours, hot rolled at 940℃, and solution treated at 1040℃ for 1.5 hours before being water quenched.

[0102] Subsequently, a 60% first cold rolling deformation, an intermediate aging treatment at 500℃ for 2 hours, and a 30% second cold rolling deformation were carried out.

[0103] Unlike Example 4, a secondary aging treatment was added after the second cold rolling, with a treatment temperature of 350°C and a holding time of 30 minutes.

[0104] Performance tests showed that the CuCrSn alloy plate had a tensile strength of 602.8 MPa, an electrical conductivity of 74.9% IACS, and a strength-ductility product of 8.05 GPa·s.

[0105] By comparing the results obtained from Examples 1-4 with those from Comparative Examples 1-4, the following conclusions can be drawn: Comparing Example 1 and Comparative Example 1, it can be seen that, under the same alloy composition and rolling and aging processes, reducing the solution treatment temperature from 1000℃ to 960℃ resulted in a decrease in the tensile strength of the resulting CuCrSn alloy from 601.8 MPa to 578.4 MPa. This indicates that the solution treatment temperature has a significant impact on the solid solution state of Cr in the Cu matrix. When a solution treatment is performed at 1000℃, the degree of Cr solubility in the Cu matrix can be increased, allowing more precipitable Cr elements to remain in the solution-treated billet, providing an element source for Cr precipitation during the intermediate aging process. However, reducing the solution treatment temperature limits the extent to which Cr elements enter the Cu matrix, reducing the precipitation strengthening effect formed during the aging process and leading to a decrease in alloy strength.

[0106] Comparing Example 2 and Comparative Example 2, it can be seen that, under the same alloy composition and solution treatment conditions, adjusting the staged processing of first cold rolling, intermediate aging, and second cold rolling to a single 90% cold rolling deformation followed by aging treatment, the tensile strength of the resulting CuCrSn alloy decreased from 624.8 MPa to 530.9 MPa, and the electrical conductivity decreased from 74.3% IACS to 69.2% IACS. The results indicate that a high degree of local deformation concentration is easily generated during a single large deformation process, causing changes in the dislocation distribution and affecting the diffusion and precipitation process of Cr elements in the dislocation region. This invention employs a combined processing of first cold rolling, intermediate aging, and second cold rolling, allowing the deformation process to proceed in stages. This facilitates the formation of a more uniform deformed microstructure and promotes the interaction between Cr-rich precipitates and the deformed structure, thereby improving the alloy strength while maintaining good electrical conductivity.

[0107] Comparing Example 3 and Comparative Example 3, it can be seen that, under the same alloy composition, solution treatment, and cold rolling process, reducing the intermediate aging temperature from 500℃ to 400℃ resulted in a decrease in the tensile strength of the resulting CuCrSn alloy from 636.4 MPa to 565.7 MPa. This indicates that the intermediate aging temperature plays a crucial role in the diffusion and precipitation process of Cr. When intermediate aging treatment is used within the range of 450~500℃, it can promote the diffusion of Cr in the supersaturated Cu matrix and the formation of precipitates. However, after reducing the aging temperature, the diffusion rate of Cr decreases, the precipitation phase formation process is affected, the precipitation strengthening effect is weakened, and the alloy strength decreases.

[0108] Comparing Example 4 with Comparative Example 4, it can be seen that under the same alloy composition and pretreatment conditions, the tensile strength of the resulting CuCrSn alloy decreased from 644.4 MPa to 602.8 MPa after adding a second aging treatment. The results indicate that after the intermediate aging treatment, supersaturated Cr elements in the Cu matrix precipitated, forming a certain number of Cr-rich precipitates. Further aging treatment easily leads to microstructural recovery within the alloy, affecting the deformed structure formed during cold rolling and resulting in a reduced strengthening effect.

[0109] In summary, as can be seen from the above embodiments and comparative examples, the present invention uses the above-mentioned 1000~1040℃ solution treatment to allow Cr elements to fully enter the Cu matrix to form a supersaturated solution state. Combined with the staged processing of the first cold rolling, intermediate aging and the second cold rolling, the precipitation strengthening and deformation strengthening of Cr work together to obtain a CuCrSn alloy with high strength and electrical conductivity.

[0110] Therefore, by adopting the above-mentioned high-strength and high-conductivity CuCrSn alloy and its preparation method, the internal microstructure of the alloy is improved by controlling the solid solution, rolling and aging processes of the CuCrSn alloy, so that the Cr element can fully participate in the formation of the strengthening phase, thereby improving the alloy strength while maintaining high conductivity, and obtaining a CuCrSn alloy with high strength and high conductivity.

[0111] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0112] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing a high-strength, high-conductivity CuCrSn alloy, characterized in that, Includes the following steps: S1. The CuCrSn alloy ingot is homogenized and hot-rolled to obtain a hot-rolled billet. S2. The hot-rolled billet is subjected to solution treatment to obtain a supersaturated solution-treated billet. S3. Perform a first cold rolling deformation on the supersaturated solid solution billet to obtain a first cold-rolled billet; S4. The first cold-rolled billet is subjected to intermediate aging treatment to precipitate the Cr element dissolved in the Cu matrix and obtain an intermediate-aged billet. S5. Perform a second cold rolling deformation on the intermediate aging billet to obtain a high-strength, high-conductivity CuCrSn alloy.

2. The preparation method according to claim 1, characterized in that, In step S1, the homogenization treatment temperature is 940~980℃, and the holding time is 4~6h.

3. The preparation method according to claim 1, characterized in that, In step S1, the hot rolling temperature is 900~940℃, and the total hot rolling reduction is not less than 50%.

4. The preparation method according to claim 1, characterized in that, In step S2, the solution treatment temperature is 1000~1040℃, and the holding time is 60~90min.

5. The preparation method according to claim 4, characterized in that, The billet after solution treatment is cooled by water quenching at a rate of not less than 120°C / s, so that the Cr element after solution treatment remains in the Cu matrix to form a supersaturated solid solution state.

6. The preparation method according to claim 1, characterized in that, In step S3, the deformation amount of the first cold rolling deformation is 60~70%.

7. The preparation method according to claim 1, characterized in that, In step S4, the intermediate aging treatment temperature is 450~500℃, and the holding time is 1~2h.

8. The preparation method according to claim 1, characterized in that, In step S5, the deformation amount of the second cold rolling deformation is 20~30%.

9. A high-strength, high-conductivity CuCrSn alloy prepared by the preparation method according to any one of claims 1 to 8, characterized in that, The high-strength, high-conductivity CuCrSn alloy comprises, by weight percentage: Cr: 0.6~0.9wt% Sn: 0.1~0.3wt% The balance is Cu.

10. The high-strength, high-conductivity CuCrSn alloy according to claim 9, characterized in that, The high-strength, high-conductivity CuCrSn alloy has a tensile strength of not less than 600 MPa and an electrical conductivity of not less than 70% IACS.

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