Cu-Ti alloy and preparation method thereof

Abstract

The invention provides a Cu-Ti alloy and a preparation method thereof. The Cu-Ti alloy comprises the following components in percentage by mass: 3.0-3.5 wt% of Ti element, less than or equal to 0.05 wt% of B element, less than or equal to 0.05 wt% of Zr element and the balance of Cu element, the Cu-Ti alloy comprises a beta '-Cu4Ti precipitation phase with the size being 3 nm to 7 nm, a beta'-Cu4Ti precipitation phase with the size being 8 nm to 12 nm and a beta '-Cu4Ti precipitation phase with the size being 13 nm to 20 nm. The precipitated phases comprise microstructures with the size ranges of 3-7 nm, 8-12 nm and 13-20 nm, the microstructures jointly act on an alloy matrix, the strength, plasticity and conductivity of the Cu-Ti alloy material are remarkably improved, and therefore the problem that the Cu-Ti alloy material is difficult to give consideration to excellent strength, conductivity and plasticity at the same time is solved.

Description

Technical Field

[0001] This invention relates to the field of Cu-Ti alloy preparation technology, and more specifically, to a Cu-Ti alloy and its preparation method. Background Technology

[0002] High-strength, high-elasticity, and conductive copper alloys have been widely used in instruments, elastic components, and conductive and thermally conductive components, such as various current-carrying elastic elements, contact springs, switches, converters, and terminal components. With the acceleration of informatization, automation, and intelligentization, the integration of electronic components is increasing, and conductive copper alloy elastic components are gradually becoming miniaturized, thinner, and more irregularly shaped. This places higher demands on the mechanical, electrical, and application performance of copper alloys. Therefore, there is an urgent need to research, develop, and apply high-strength, high-ductility, and conductive elastic copper alloy materials and their preparation technologies.

[0003] Currently, among existing copper alloys, high-strength, high-elasticity copper alloys with tensile strengths exceeding 1000 MPa mainly include Cu-Be, Cu-Ti, Cu-Ni-Sn, and Cu-Ni-Si alloys. Among these, Cu-Be alloy is the most historically advanced, technologically mature, and best-performing elastic copper alloy, often referred to as the "King of Elasticity." However, this alloy suffers from problems such as high raw material costs, stringent heat treatment requirements, large heat treatment deformation, poor high-temperature relaxation resistance, and the generation of toxic Be oxides during processing. With increasing societal emphasis on health and environmental protection, since the late 20th century, elastic copper alloys have gradually evolved towards low-beryllium to beryllium-free, green, and renewable directions. In recent years, the development of Cu-Be alloys has accelerated, particularly in terms of application limitations and alternatives. Numerous studies have shown that, compared to Cu-Ni-Sn and Cu-Ni-Si alloys, Cu-Ti alloys are considered the most promising high-strength, high-elasticity, and conductive copper alloys to replace Cu-Be alloys. The reason lies in the fact that this alloy system possesses mechanical properties comparable to Cu-Be alloys, better bending workability, higher heat resistance, and superior stress relaxation resistance. Furthermore, Ti resources are abundant and raw material prices are relatively low. Therefore, considering factors such as performance, environmental friendliness, resources, and cost, the Cu-Ti alloy system of high-strength, conductive, and elastic materials demonstrates its superiority.

[0004] However, numerous studies have shown that a key problem with this alloy system is that while strength is improved, electrical conductivity is difficult to significantly increase. Whether produced by leading international Japanese companies or domestically from various Chinese enterprises, Cu-Ti alloy sheets and strips with tensile strengths exceeding 1000 MPa generally exhibit electrical conductivity below 15% IACS, severely limiting their wider application. To effectively improve the performance of this alloy system, extensive research has been conducted both domestically and internationally on composition, processing, aging precipitation behavior, strengthening, and conductivity mechanisms. Studies have shown that the strength of Cu-Ti alloys can be significantly improved through aging control; however, even in the peak-aged state, 0.45–0.9 wt.% Ti atoms are dissolved in the matrix. Due to the radius of Ti atoms… Compared to the atomic radius of Cu A concentration of 13.28% will cause significant lattice distortion, resulting in greater electron scattering. Ultimately, the Ti element dissolved in the alloy matrix will significantly reduce the alloy's electrical conductivity. This is the key reason why, even when the strength of this alloy is adjusted to above 1000 MPa, its electrical conductivity is generally below 15% IACS. To effectively improve the electrical conductivity of this alloy, studies on its aging precipitation behavior revealed that its microstructure evolution mainly follows this sequence: supersaturated Cu solid solution (FCC structure) undergoes amplitude modulation decomposition to form two disordered FCC structural phases (Ti-poor and Ti-rich regions). Subsequently, the disordered Ti-rich regions undergo continuous ordering transformation into a dispersed, acicular metastable coherent phase β′-Cu4Ti (tetragonal structure, Ni4Mo type, I4 / m). At peak aging, the microstructure includes α-solid solution and the β′-Cu4Ti phase. Further aging to over-aging results in the β′-Cu4Ti phase forming a lamellar β-Cu4Ti phase (orthorhombic structure, Au4Zr type, Pnma) through discontinuous nucleation and growth. The size, morphology, structure, and distribution of these phases significantly influence the alloy's strength and electrical conductivity. Therefore, recent years have seen numerous studies on the effects of adding microalloying elements on the aging precipitation behavior of alloys, such as the addition of Fe, Ni, Sn, Zr, Co, Cr, Cd, B, and Mg. The results show that the addition of these elements does have some effect on the precipitation of alloys, but the effect is not significant and it is still difficult to effectively solve the common key problem of synergistic improvement of the strong and electrical properties of this series of alloys.

[0005] Based on composition design and microalloying control, extensive research has been conducted on improving the strength and electrical conductivity of alloys through deformation heat treatment, ultimately aiming to significantly enhance the strength-electrical properties of this alloy system through the synergistic effect of deformation strengthening and precipitation strengthening. However, to date, most research on deformation heat treatment processes focuses on directly cold rolling the solution-quenched alloy and then performing isothermal aging, or on this basis, performing secondary deformation + isothermal aging control. This not only results in poor coupling distribution of precipitated phases and dislocations, but also makes it difficult to effectively improve the electrical conductivity when the alloy strength reaches above 1000 MPa. In addition, when the tensile strength of Cu-Ti alloys exceeds 1000 MPa, their elongation is generally low, sometimes even only about 1%, resulting in insufficient bending performance and easy cracking of high-strength alloy strips. Especially for ultra-thin, irregularly shaped components using 0.1 mm thick Cu-Ti alloy strips, higher requirements are placed on the elongation of the alloy to meet their bending performance. Therefore, how to further improve the plasticity of this alloy strip system is also a key issue in the near future.

[0006] Based on the performance requirements of next-generation conductive copper alloy elastic components, and considering that the key factors affecting alloy strength, conductivity, and plasticity remain composition and processing, especially processing, to achieve a synergistic improvement in the overall performance of this alloy system, it is necessary to break away from traditional microstructure design and control approaches. Only through the development of new microstructure design and control processes can breakthroughs in the synergistic improvement of the alloy system's overall performance be achieved. Therefore, it is essential to develop a high-strength, high-plasticity, conductive Cu-Ti alloy material and its preparation technology that do not increase alloy production costs while possessing excellent comprehensive performance, thereby better meeting the urgent needs of high-tech fields for this type of material. Furthermore, this novel Cu-Ti alloy material and its preparation process will also provide important inspiration and impetus for the further development of other novel metallic materials. Summary of the Invention

[0007] The main objective of this invention is to provide a Cu-Ti alloy and its preparation method, so as to solve the problem that Cu-Ti alloy materials in the prior art are difficult to simultaneously achieve excellent strength, electrical conductivity and plasticity.

[0008] To achieve the above objectives, according to one aspect of the present invention, a Cu-Ti alloy is provided, comprising, by mass percentage: 3.0 to 3.5 wt% Ti, ≤0.05 wt% B, ≤0.05 wt% Zr, and the balance being Cu; wherein the Cu-Ti alloy comprises β'-Cu4Ti precipitates with a size of 3 to 7 nm, β'-Cu4Ti precipitates with a size of 8 to 12 nm, and β'-Cu4Ti precipitates with a size of 13 to 20 nm.

[0009] Furthermore, the dislocation density of the above Cu-Ti alloy is (1~4)×10⁻⁶. 14 ·m -2 .

[0010] Furthermore, the spacing between adjacent particles of the β'-Cu4Ti precipitate phase with a size of 3-7 nm is 4-6 nm; and / or the spacing between adjacent particles of the β'-Cu4Ti precipitate phase with a size of 8-12 nm is 8-10 nm; and / or the spacing between adjacent particles of the β'-Cu4Ti precipitate phase with a size of 13-20 nm is 14-19 nm.

[0011] According to another aspect of the present invention, a method for preparing the aforementioned Cu-Ti alloy is provided, the method comprising the following steps performed sequentially: batching, casting, homogenization heat treatment, hot rolling deformation, cold rolling deformation, solution quenching treatment, multi-stage pre-aging treatment, first cold rolling, first cooling aging, second cold rolling, second cooling aging, third cold rolling, isothermal aging, and third cooling aging.

[0012] Furthermore, the above-mentioned multi-stage pre-aging treatment can be either a three-stage pre-aging process or a two-stage pre-aging process. The three-stage pre-aging process includes a first-stage pre-aging, a second-stage pre-aging, and a third-stage pre-aging, performed sequentially. The first-stage pre-aging temperature is 440–500℃, and the time is 5–30 min; the second-stage pre-aging temperature is 390–435℃, and the time is 5–30 min; the third-stage pre-aging temperature is 340–385℃, and the time is 5–30 min. The two-stage pre-aging process includes a first-stage pre-aging and a second-stage pre-aging, performed sequentially. The first-stage pre-aging temperature is 440–500℃, and the time is 5–30 min; the second-stage pre-aging temperature is 390–435℃, and the time is 15–45 min; or, the first-stage pre-aging temperature is 440–500℃, and the time is 5–30 min; the second-stage pre-aging temperature is 330–385℃, and the time is 25–60 min.

[0013] Furthermore, the temperature of the first cold rolling is 25-30℃, the total deformation is 40-60%, the deformation method is unidirectional synchronous rolling, and the deformation per pass is 5-20%; and / or the temperature of the first cooling aging is reduced from 500℃ to 350℃, the cooling rate is 0.4-0.9℃ / min, and air cooling is performed when the temperature of the first cooling aging is 350℃.

[0014] Furthermore, the temperature of the second cold rolling is 25-30℃, the total deformation is 40-60%, the deformation method is unidirectional synchronous rolling, and the deformation per pass is 5-20%; and / or the temperature of the second cooling aging is reduced from 500℃ to 350℃, the cooling rate is 0.4-0.9℃ / min, and air cooling is performed when the temperature of the second cooling aging is 350℃.

[0015] Furthermore, the temperature of the third cold rolling is 25-30°C, the total deformation is 35-55%, the deformation method is unidirectional synchronous rolling, and the deformation per pass is 5-15%.

[0016] Furthermore, the isothermal aging temperature is 350–390°C, and the heating rate is greater than 100°C / min during the process of raising the temperature to the isothermal aging temperature. After isothermal aging for 1–7 hours, the temperature is raised to the highest temperature of the third cooling aging at a rate greater than 100°C / min, and the third cooling aging is carried out. The third cooling aging reduces the temperature from 500°C to 400°C at a cooling rate of 0.4–0.9°C / min. When the temperature of the third cooling aging is 400°C, air cooling is performed.

[0017] Furthermore, the homogenization heat treatment temperature is 750–850℃, and the time is 0.5–6h; and / or the total deformation of hot rolling is 60–90%, the deformation method is unidirectional synchronous rolling, and the deformation per pass is 10–20%; and / or the temperature of cold rolling is 25–30℃, and the total deformation is 40–55%; and / or the temperature of solution quenching treatment is 800–900℃, and the time is 2–5h.

[0018] By applying the technical solution of this invention, the Cu-Ti alloy in this application optimizes the distribution of multi-scale precipitated phases without affecting the basic properties of the alloy. These precipitated phases include microstructures with sizes ranging from 3 to 7 nm, 8 to 12 nm, and 13 to 20 nm, respectively. They work together on the alloy matrix, resulting in significantly improved strength, plasticity, and electrical conductivity of the Cu-Ti alloy material. This is because precipitated phases of different scales can form a complex reinforcing network within the Cu-Ti alloy. This application utilizes the presence of precipitated phases of different scales in the Cu-Ti alloy and their influence on dislocations to effectively promote the regulation and optimization of dislocation movement, while reducing electron scattering in the Cu-Ti alloy matrix. This achieves a synergistic improvement in strength, plasticity, and electrical conductivity, which is a significant improvement and breakthrough compared to existing Cu-Ti alloy materials. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0020] Figure 1 A flow chart of the Cu-Ti alloy preparation process according to this application is shown;

[0021] Figure 2 The diagram shows the hardness change pattern of the alloy in the second cold-rolled state during the second cooling aging process according to Example 1 of this application;

[0022] Figure 3 The diagram shows the change in electrical conductivity of the alloy in the second cold-rolled state during the second cooling aging process according to Example 1 of this application;

[0023] Figure 4 The diagram shows the hardness change pattern of the alloy in the second cold-rolled state during the second cooling aging process according to Example 3 of this application;

[0024] Figure 5 The diagram shows the change in electrical conductivity of the alloy in the second cold-rolled state during the second cooling aging process according to Example 3 of this application;

[0025] Figure 6 The diagram shows the hardness change pattern of the alloy in the second cold-rolled state during the second cooling aging process according to Example 5 of this application;

[0026] Figure 7 The diagram shows the change in electrical conductivity of the alloy in the second cold-rolled state during the second cooling aging process according to Example 5 of this application;

[0027] Figure 8 The diagram shows the hardness variation of the alloys in the third cold-rolled state after isothermal aging and third cooling aging according to Examples 1, 3 and 5 of this application.

[0028] Figure 9 The diagram shows the hardness variation of the alloys in the third cold-rolled state after isothermal aging and third cooling aging according to Examples 2, 4 and 6 of this application. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0030] As analyzed in the background section of this application, the existing technology has the problem that Cu-Ti alloy materials cannot simultaneously achieve excellent strength, electrical conductivity and plasticity. In order to solve the above problems, this application provides a Cu-Ti alloy and a method for preparing the same.

[0031] In a typical embodiment of this application, a Cu-Ti alloy is provided, comprising, by mass percentage: 3.0 to 3.5 wt% Ti, ≤0.05 wt% B, ≤0.05 wt% Zr, with the balance being Cu; wherein the Cu-Ti alloy comprises β'-Cu4Ti precipitates with a size of 3 to 7 nm, β'-Cu4Ti precipitates with a size of 8 to 12 nm, and β'-Cu4Ti precipitates with a size of 13 to 20 nm.

[0032] In this application, the distribution of multi-scale precipitated phases in the Cu-Ti alloy is optimized without affecting the basic properties of the alloy. These precipitated phases include microstructures with sizes ranging from 3 to 7 nm, 8 to 12 nm, and 13 to 20 nm. They work together on the alloy matrix, resulting in significantly improved strength, plasticity, and electrical conductivity in the Cu-Ti alloy. This is because precipitated phases of different sizes can form a complex strengthening network within the Cu-Ti alloy. This application utilizes the presence of precipitated phases of different sizes in the Cu-Ti alloy and their influence on dislocations to effectively promote the regulation and optimization of dislocation movement, while reducing electron scattering in the Cu-Ti alloy matrix. This achieves a synergistic improvement in strength, plasticity, and electrical conductivity, representing a significant improvement and breakthrough compared to existing Cu-Ti alloy materials.

[0033] In one embodiment of this application, the dislocation density of the Cu-Ti alloy is (1~4)×10⁻⁶. 14 ·m -2 .

[0034] Cu-Ti alloys with the above dislocation densities not only enhance their overall strength but also ensure good ductility and high electrical conductivity. This is because smaller precipitated phases help pin dislocations more effectively, preventing their slip and annihilation, while larger precipitated phases help reduce electron scattering and improve conductivity. In this way, the overall performance of Cu-Ti alloys is balanced and optimized, especially maintaining good conductivity and ductility under high stress conditions, which is unattainable by traditional single-scale precipitation strengthening.

[0035] In one embodiment of this application, the spacing between adjacent particles of the β'-Cu4Ti precipitate phase with a size of 3-7 nm is 4-6 nm; and / or the spacing between adjacent particles of the β'-Cu4Ti precipitate phase with a size of 8-12 nm is 8-10 nm; and the spacing between adjacent particles of the β'-Cu4Ti precipitate phase with a size of 13-20 nm is 14-19 nm.

[0036] This invention achieves precise control over the microstructure of the alloy by adjusting the spacing between adjacent particles within precipitate phases of different sizes (3–7 nm, 8–12 nm, and 13–20 nm) within the aforementioned ranges. Specifically, by setting the spacing between adjacent particles of the 3–7 nm, 8–12 nm, and 13–20 nm precipitate phases within these ranges, the aggregation of coarse precipitate phases is effectively suppressed, avoiding potential performance degradation. Simultaneously, the uniformity and stability of the alloy's internal structure are ensured, further enhancing the alloy's performance. This optimization of multi-scale precipitate phases and their interaction with dislocations enables the Cu-Ti alloy of this invention to achieve electrical conductivity far exceeding that of conventional Cu-Ti alloys while maintaining high strength and high plasticity, meeting the urgent needs of the electronics, aerospace, and other high-tech industries for high-performance copper alloy materials.

[0037] In another typical embodiment of this application, a method for preparing the above-mentioned Cu-Ti alloy is provided, such as... Figure 1 As shown, the preparation method includes the following steps performed in sequence: batching, casting, homogenization heat treatment, hot rolling deformation, cold rolling deformation, solution quenching treatment, multi-stage pre-aging treatment, first cold rolling, first cooling aging, second cold rolling, second cooling aging, third cold rolling, isothermal aging, and third cooling aging.

[0038] The above-mentioned Cu-Ti alloy preparation method, by changing the process route after solution quenching, from the traditional process route (e.g., solution quenching → cold deformation → isothermal aging, solution → cold deformation → isothermal aging → cold deformation → isothermal aging) to the new process route, not only promotes the rapid precipitation of a large number of multi-scale precipitates in the alloy matrix by first performing multi-stage pre-aging control on the solution-quenched alloy, thus enabling it to synergistically influence the degree of dislocation slip, pile-up, and annihilation during the subsequent cold rolling process, but also actively influences the diffusion and enrichment of solute elements, as well as the growth and distribution of precipitates during the aging process through synergistic effects. This successfully achieves precise control of the microstructure of Cu-Ti alloy, ultimately resulting in an effective improvement in the alloy's strength, plasticity, and conductivity. Furthermore, based on this, the present invention breaks away from the traditional deformation heat treatment control approach (cold rolling + isothermal aging control process), and innovatively proposes a method for synergistic control of multi-scale precipitate precipitation, growth, and their coupling distribution with dislocations, based on a first cold rolling + first cooling aging + second cold rolling + second cooling aging, and a third cold rolling + isothermal aging + third cooling aging. This method not only enables the multi-scale precipitates precipitated under the control of multi-stage pre-aging to be reasonably coarsened, but also induces more multi-scale precipitates to precipitate and affect dislocation slip and distribution. Ultimately, based on the formation of multi-scale precipitates and their coupling distribution with dislocations, the strength, conductivity, and plasticity of this alloy are significantly improved.

[0039] In one embodiment of this application, the above-mentioned multi-stage pre-aging process is a three-stage pre-aging or a two-stage pre-aging. The three-stage pre-aging includes a first-stage pre-aging, a second-stage pre-aging, and a third-stage pre-aging performed sequentially. The first-stage pre-aging temperature is 440–500°C, and the time is 5–30 min; the second-stage pre-aging temperature is 390–435°C, and the time is 5–30 min; the third-stage pre-aging temperature is 340–385°C, and the time is 5–30 min. The two-stage pre-aging includes a first-stage pre-aging and a second-stage pre-aging performed sequentially. The first-stage pre-aging temperature is 440–500°C, and the time is 5–30 min; the second-stage pre-aging temperature is 390–435°C, and the time is 15–45 min. Alternatively, the first-stage pre-aging temperature is 440–500°C, and the time is 5–30 min; the second-stage pre-aging temperature is 330–385°C, and the time is 25–60 min.

[0040] The multi-stage pre-aging treatment mentioned in this application, whether three-stage or two-stage, hinges on the ability to control the diffusion and enrichment of solute atoms in the alloy through carefully designed temperature and time parameters, thereby promoting the formation of specific microstructures within different temperature ranges. Three-stage pre-aging is preferred. The first stage, performed at a higher temperature, facilitates the initiation of initial precipitation within the alloy. The second and third stages, performed at slightly lower temperatures, refine the precipitated phase and optimize its distribution. These steps collectively constitute an efficient and controllable precipitation process, enabling the alloy to exhibit excellent comprehensive properties, including but not limited to high strength, high plasticity, and high electrical conductivity, during subsequent cold rolling and non-isothermal aging treatments.

[0041] In one embodiment of this application, the temperature of the first cold rolling is 25-30°C, the total deformation is 40-60%, the deformation method is unidirectional synchronous rolling, and the deformation per pass is 5-20%; and / or the temperature of the first cooling aging is reduced from 500°C to 350°C, the cooling rate is 0.4-0.9°C / min, and after the first cooling aging to 350°C, air cooling is performed directly.

[0042] This application specifies in detail the conditions for the first cold rolling and the first cooling aging. This method, combining cold rolling and cooling aging, not only effectively utilizes the residual thermal stress within the alloy to promote dislocation rearrangement and optimize the distribution of precipitated phases, but also prevents performance degradation caused by excessive heat treatment. During the first cooling aging process, as the temperature decreases, dislocation activity decreases, and the growth rate of the precipitated phase is controlled, thus forming a unique microstructure within the alloy—a multi-scale coupled distribution of precipitated phases and dislocations. This provides an ideal strengthening mechanism for the alloy while maintaining good plasticity and electrical conductivity.

[0043] Technically, the dislocation density and precipitate distribution within the alloy can be further controlled through the first cold rolling and the first cooling aging process, thereby improving the alloy's overall performance. In principle, the first cold rolling increases the dislocation density, while the first cooling aging promotes the precipitation and growth of the precipitate phase, thus affecting the alloy's strength and conductivity. Specifically, the alloy's strength and conductivity are significantly improved.

[0044] To further regulate the dislocation density and precipitate phase distribution within the alloy and improve its overall performance, in one embodiment of this application, the temperature of the second cold rolling is 25–30°C, the total deformation is 40–60%, the deformation method is unidirectional synchronous rolling, and the deformation per pass is 5–20%; and / or the temperature of the second cooling aging is reduced from 500°C to 350°C, the cooling rate is 0.4–0.9°C / min, and after the second cooling aging to 350°C, it is directly air-cooled.

[0045] In one embodiment of this application, the temperature of the third cold rolling is 25-30°C, the total deformation is 35-55%, the deformation method is unidirectional synchronous rolling, and the deformation per pass is 5-15%.

[0046] By controlling the specific conditions of the third cold rolling within the aforementioned range, the microstructure of the alloy was further refined, resulting in a more uniform size distribution of the previously formed precipitated phases. This also increased the alloy's deformation energy storage, providing greater flexibility for subsequent heat treatment. Through this step, the alloy not only withstands more processing deformation but also exhibits better performance stability during subsequent heat treatment.

[0047] In one embodiment of this application, the isothermal aging temperature is 350-390°C, and the heating rate is greater than 100°C / min during the process of heating to the isothermal aging temperature. After isothermal aging for 1-7 hours, the temperature is increased to the highest temperature of the third cooling aging at a rate greater than 100°C / min, and the third cooling aging is performed. The third cooling aging reduces the temperature from 500°C to 400°C at a rate of 0.4-0.9°C / min. After the third cooling aging reaches 400°C, air cooling is performed.

[0048] This application employs a combined isothermal aging and third-stage cooling aging method to further optimize the microstructure of the alloy. First, by controlling the isothermal aging temperature and time within the aforementioned range, the growth of fine precipitate phases is promoted, while dislocation density is reduced, achieving a purifying effect on the matrix. Then, during the third-stage cooling aging process, the continuous cooling from high to low temperature not only mitigates the adverse risks of sudden temperature changes but also promotes the growth of larger-scale precipitate phases, further improving the alloy's strength and toughness. This method effectively balances the precipitation and dislocation annihilation processes, ensuring that the alloy achieves high strength without sacrificing its plasticity and electrical conductivity.

[0049] In one embodiment of this application, the homogenization heat treatment temperature is 750–850°C, and the time is 0.5–6 h; and / or the total deformation of hot rolling is 60–90%, the deformation method is unidirectional synchronous rolling, and the deformation per pass is 10–20%; and / or the temperature of cold rolling is 25–30°C, and the total deformation is 40–55%; and / or the temperature of solution quenching is 800–900°C, and the time is 2–5 h.

[0050] By controlling the conditions of homogenization heat treatment, hot rolling deformation, cold rolling deformation, and subsequent solution quenching within the aforementioned ranges, these pretreatment steps aim to minimize compositional segregation and microstructural defects in the alloy ingot, laying a solid foundation for subsequent multi-stage pre-aging and deformation heat treatment. The combination of homogenization heat treatment and hot rolling deformation optimizes the original microstructure of the alloy through high-temperature dissolution and dynamic recrystallization, reducing initial dislocation density and thus improving the overall homogeneity of the alloy and the effectiveness of subsequent heat treatment. Solution quenching, through rapid cooling, retains a large number of supersaturated solute atoms, providing the necessary preconditions for multi-stage pre-aging treatment and ensuring optimized formation and distribution of subsequent precipitated phases.

[0051] The beneficial effects of this application will be further illustrated below with reference to the embodiments.

[0052] The following examples are based on Figure 1 The Cu-Ti alloy preparation process is shown in the flowchart below.

[0053] Example 1

[0054] First, the alloy is prepared according to the designed composition values ​​and then melted and cast. The raw materials used for melting and casting are 99.9 wt% electrolytic high-purity Cu and sponge Ti. First, a Cu-3.3 wt% Ti alloy is prepared and placed in a medium-frequency induction melting furnace. Once the vacuum degree is less than 0.1 Pa, the temperature is raised directly using high-power heating until the melt is completely melted and the temperature reaches 1250℃. This temperature is held for 5 minutes, and then the melt is stirred electromagnetically for 70 seconds. After the melt temperature stabilizes at around 1250℃, casting begins, controlling the casting speed to minimize shrinkage cavities. Then, the ingot undergoes homogenization treatment and subsequent multi-process control, specifically as follows: homogenization heat treatment + hot rolling deformation (homogenization heat treatment). Processing temperature: 800℃, time: 2h; heating rate: 50℃ / min, hot rolling deformation after homogenization: 70%, deformation per pass: 15%, deformation method: unidirectional synchronous rolling) → cold rolling deformation (deformation temperature: room temperature, deformation: 45%) → solution quenching treatment (temperature: 850℃, time: 3h, water quenching) → multi-stage pre-aging treatment (three-stage pre-aging: 480℃ / 15min + 410℃ / 15min + 360℃ / 15min, heating rate: 150℃ / min, air cooling to room temperature after pre-aging) → First cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 50%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.8℃ / min, after cooling to the minimum temperature, directly air-cooled) → Second cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 50%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.8℃ / min, cooling) After aging to the minimum temperature, the alloy is directly air-cooled → third cold rolling (deformation temperature: room temperature, deformation amount: 40%, deformation per pass: 10%, deformation method: unidirectional synchronous rolling) → isothermal aging + cooling aging (isothermal temperature: 380℃, heating rate: 150℃ / min, time: 2h, then directly heating at a rate of 150℃ / min to the highest cooling aging temperature for cooling aging, cooling aging temperature range: 500→400℃, cooling rate: 0.8℃ / min, and air-cooled directly after cooling to the minimum temperature). Finally, the microhardness, electrical conductivity, and tensile properties of typical aged alloys are characterized, as shown in Tables 1 and 2. Figure 2 As shown in 3 and 8.

[0055] Example 2

[0056] First, the alloy is prepared according to the designed composition values ​​and then melted and cast. The raw materials used for melting and casting are 99.9 wt% electrolytic high-purity Cu and sponge Ti. First, a Cu-3.3 wt% Ti alloy is prepared and placed in a medium-frequency induction melting furnace. Once the vacuum degree is less than 0.1 Pa, the temperature is raised directly using high-power heating until the melt is completely melted and the temperature reaches 1200℃. This temperature is held for 3 minutes, and then the melt is stirred electromagnetically for 30 seconds. After the melt temperature stabilizes at around 1250℃, casting begins, controlling the casting speed to minimize shrinkage cavities. Then, the ingot undergoes homogenization treatment and subsequent multi-process control, specifically as follows: homogenization heat treatment + hot rolling deformation (homogenization heat treatment). Processing temperature: 750℃, time: 0.5h; heating rate: 20℃ / min, hot rolling deformation after homogenization: 60%, deformation per pass: 10%, deformation method: unidirectional synchronous rolling) → cold rolling deformation (deformation temperature: room temperature, deformation: 40%) → solution quenching treatment (temperature: 800℃, time: 2h, water quenching) → multi-stage pre-aging treatment (three-stage pre-aging: 450℃ / 25min + 390℃ / 25min + 340℃ / 25min, heating rate: 150℃ / min, air cooling after pre-aging) Room temperature) → First cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 40%, deformation method: unidirectional synchronous rolling, deformation amount per pass: 5%, cooling aging temperature range: 500→350℃, cooling rate: 0.4℃ / min, after cooling to the minimum temperature, directly air-cool) → Second cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 60%, deformation method: unidirectional synchronous rolling, deformation amount per pass: 20%, cooling aging temperature range: 500→350℃, cooling rate: 0.9℃ / min, cooling) After aging to the minimum temperature, the alloy is directly air-cooled → third cold rolling (deformation temperature: room temperature, deformation amount: 55%, per pass deformation amount: 15%, deformation method: unidirectional synchronous rolling) → isothermal aging + cooling aging (isothermal temperature: 390℃, heating rate: 150℃ / min, time: 7h, then directly heating at a rate of 150℃ / min to the highest cooling aging temperature for cooling aging, cooling aging temperature range: 500→400℃, cooling rate: 0.9℃ / min, after cooling aging to the minimum temperature, the alloy is directly air-cooled). Finally, the microhardness, electrical conductivity and tensile properties of typical aged alloys are characterized, as shown in Tables 1 and 2, and... Figure 9 As shown.

[0057] Example 3

[0058] First, the alloy was prepared according to the designed composition values ​​and then melted and cast. The raw materials used for melting and casting included 99.9 wt% electrolytic high-purity Cu and sponge Ti. First, a Cu-3.3 wt% Ti alloy was prepared and placed in a medium-frequency induction melting furnace. Once the vacuum level was less than 0.1 Pa, the temperature was raised directly using high-power heating until the melt was completely melted and the temperature reached 1300℃. This temperature was held for 7 minutes, and then the melt was stirred electromagnetically for 90 seconds. After the melt temperature stabilized at around 1250℃, casting began, controlling the casting speed to minimize shrinkage cavities. Then, the ingot underwent homogenization treatment and subsequent multi-process control, specifically as follows: homogenization heat treatment + hot rolling deformation (homogenization...). Homogenization heat treatment temperature: 850℃, time: 4h; heating rate: 80℃ / min, hot rolling deformation after homogenization: 80%, deformation per pass: 20%, deformation method: unidirectional synchronous rolling) → cold rolling deformation (deformation temperature: room temperature, deformation: 55%) → solution quenching treatment (temperature: 900℃, time: 5h, water quenching) → multi-stage pre-aging treatment (double-stage pre-aging: 500℃ / 5min + 435℃ / 15min, heating rate: 150℃ / min, air cooling to room temperature after pre-aging) → first Cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 60%, deformation method: unidirectional synchronous rolling, deformation per pass: 20%, cooling aging temperature range: 500→350℃, cooling rate: 0.9℃ / min, air cooling directly after cooling to the minimum temperature) → second cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 40%, deformation method: unidirectional synchronous rolling, deformation per pass: 5%, cooling aging temperature range: 500→350℃, cooling rate: 0.4℃ / min, cooling aging to the minimum temperature) After reaching the lowest temperature, the alloy is directly air-cooled → third cold rolling (deformation temperature: room temperature, deformation amount: 35%, deformation per pass: 5%, deformation method: unidirectional synchronous rolling) → isothermal aging + cooling aging (isothermal temperature: 350℃, heating rate: 150℃ / min, time: 1h, then directly heating at a rate of 150℃ / min to the highest cooling aging temperature for cooling aging, cooling aging temperature range: 500→400℃, cooling rate: 0.4℃ / min, after cooling to the lowest temperature, the alloy is directly air-cooled). Finally, the microhardness, electrical conductivity and tensile properties of typical aged alloys are characterized, as shown in Tables 1 and 2, and... Figure 4 As shown in 5 and 8.

[0059] Example 4

[0060] First, the alloy was prepared according to the designed composition values ​​and then melted and cast. The raw materials used for melting and casting included 99.9 wt% electrolytic high-purity Cu and sponge Ti. First, a Cu-3.3 wt% Ti alloy was prepared and placed in a medium-frequency induction melting furnace. Once the vacuum level was less than 0.1 Pa, the temperature was raised directly using high-power heating until the melt was completely melted and the temperature reached 1200℃. This temperature was held for 5 minutes, and then the melt was stirred electromagnetically for 80 seconds. After the melt temperature stabilized at around 1250℃, casting began, controlling the casting speed to minimize shrinkage cavities. Then, the ingot underwent homogenization treatment and subsequent multi-process control, specifically as follows: homogenization heat treatment + hot rolling deformation (homogenization...). Homogenization heat treatment temperature: 800℃, time: 3h; heating rate: 60℃ / min, hot rolling deformation after homogenization: 70%, deformation per pass: 15%, deformation method: unidirectional synchronous rolling) → cold rolling deformation (deformation temperature: room temperature, deformation: 45%) → solution quenching treatment (temperature: 850℃, time: 3h, water quenching) → multi-stage pre-aging treatment (double-stage pre-aging: 440℃ / 25min + 390℃ / 40min, heating rate: 180℃ / min, air cooling to room temperature after pre-aging) → first Cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 60%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.9℃ / min, air cooling directly after cooling to the minimum temperature) → second cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 40%, deformation method: unidirectional synchronous rolling, deformation per pass: 10%, cooling aging temperature range: 500→350℃, cooling rate: 0.9℃ / min, air cooling directly after cooling to the minimum temperature) → second cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 40%, deformation method: unidirectional synchronous rolling, deformation per pass: 10%, cooling aging temperature range: 500→350℃, cooling rate: 0.9℃ / min, air cooling directly after cooling to the minimum temperature) After reaching the lowest temperature, the alloy is directly air-cooled → third cold rolling (deformation temperature: room temperature, deformation amount: 40%, per pass deformation amount: 10%, deformation method: unidirectional synchronous rolling) → isothermal aging + cooling aging (isothermal temperature: 390℃, heating rate: 150℃ / min, time: 5h, then directly heating at a rate of 180℃ / min to the highest cooling aging temperature for cooling aging, cooling aging temperature range: 500→400℃, cooling rate: 0.9℃ / min, after cooling to the lowest temperature, the alloy is directly air-cooled). Finally, the microhardness, electrical conductivity and tensile properties of typical aged alloys are characterized, as shown in Tables 1 and 2, and... Figure 9 As shown.

[0061] Example 5

[0062] Based on the designed composition of the invented alloy, the alloy was first melted and cast. The raw materials used for melting and casting included 99.9 wt% electrolytic high-purity Cu and sponge Ti. First, a Cu-3.3 wt% Ti alloy was prepared and placed in a medium-frequency induction melting furnace. Once the vacuum level was less than 0.1 Pa, the temperature was raised directly using high-power heating until the melt was completely melted and the temperature reached 1300℃. This temperature was held for 7 minutes, followed by high-power electromagnetic stirring of the melt for 90 seconds. Then, once the melt temperature stabilized at approximately 1250℃, casting began, controlling the casting speed to minimize shrinkage cavities. The ingot then underwent homogenization treatment and subsequent multi-process control, specifically: homogenization heat treatment + hot rolling deformation (homogenization...). Homogenization heat treatment temperature: 850℃, time: 4h; heating rate: 80℃ / min, hot rolling deformation after homogenization: 80%, deformation per pass: 20%, deformation method: unidirectional synchronous rolling) → cold rolling deformation (deformation temperature: room temperature, deformation: 55%) → solution quenching treatment (temperature: 900℃, time: 5h, water quenching) → multi-stage pre-aging treatment (double-stage pre-aging: 500℃ / 5min + 330℃ / 50min, heating rate: 200℃ / min, air cooling to room temperature after pre-aging) → first cooling Rolling + cooling aging (deformation temperature: room temperature, deformation amount: 40%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.9℃ / min, air cooling directly after cooling to the minimum temperature) → second cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 60%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.9℃ / min, air cooling directly after cooling to the minimum temperature) → second cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 60%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.9℃ / min, air cooling directly after cooling to the minimum temperature) After reaching the lowest temperature, the alloy is directly air-cooled → third cold rolling (deformation temperature: room temperature, deformation amount: 45%, per pass deformation amount: 10%, deformation method: unidirectional synchronous rolling) → isothermal aging + cooling aging (isothermal temperature: 390℃, heating rate: 200℃ / min, time: 4h, then directly heating at a rate of 120℃ / min to the highest cooling aging temperature for cooling aging, cooling aging temperature range: 500→400℃, cooling rate: 0.9℃ / min, after cooling to the lowest temperature, the alloy is directly air-cooled). Finally, the microhardness, electrical conductivity and tensile properties of typical aged alloys are characterized, as shown in Tables 1 and 2, and... Figure 6 As shown in 7 and 8.

[0063] Example 6

[0064] First, the alloy was prepared according to the designed composition values ​​and then melted and cast. The raw materials used for melting and casting included 99.9 wt% electrolytic high-purity Cu and sponge Ti. First, a Cu-3.3 wt% Ti alloy was prepared and placed in a medium-frequency induction melting furnace. Once the vacuum level was less than 0.1 Pa, the temperature was raised directly using high-power heating until the melt was completely melted and the temperature reached 1300℃. This temperature was held for 7 minutes, and then the melt was stirred electromagnetically for 90 seconds. After the melt temperature stabilized at around 1250℃, casting began, controlling the casting speed to minimize shrinkage cavities. Then, the ingot underwent homogenization treatment and subsequent multi-process control, specifically as follows: homogenization heat treatment + hot rolling deformation (homogenization...). Homogenization heat treatment temperature: 850℃, time: 4h; heating rate: 80℃ / min, hot rolling deformation after homogenization: 80%, deformation per pass: 20%, deformation method: unidirectional synchronous rolling) → cold rolling deformation (deformation temperature: room temperature, deformation: 55%) → solution quenching treatment (temperature: 900℃, time: 5h, water quenching) → multi-stage pre-aging treatment (double-stage pre-aging: 440℃ / 25min + 380℃ / 25min, heating rate: 200℃ / min, air cooling to room temperature after pre-aging) → first Cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 40%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.9℃ / min, air cooling directly after cooling to the minimum temperature) → second cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 60%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.9℃ / min, air cooling directly after cooling to the minimum temperature) → second cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 60%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.9℃ / min, air cooling directly after cooling to the minimum temperature) After reaching the lowest temperature, the alloy is directly air-cooled → third cold rolling (deformation temperature: room temperature, deformation amount: 45%, deformation per pass: 10%, deformation method: unidirectional synchronous rolling) → isothermal aging + cooling aging (isothermal temperature: 390℃, heating rate: 200℃ / min, time: 7h, then directly heating at a rate of 120℃ / min to the highest cooling aging temperature for cooling aging, cooling aging temperature range: 500→400℃, cooling rate: 0.9℃ / min, after cooling to the lowest temperature, the alloy is directly air-cooled). Finally, the microhardness, electrical conductivity and tensile properties of typical aged alloys are characterized, as shown in Tables 1 and 2, and... Figure 9 As shown.

[0065] Example 7

[0066] The difference from Example 1 is that the multi-stage pre-aging treatment (three-stage pre-aging: 430℃ / 15min + 400℃ / 15min + 380℃ / 15min, heating rate: 150℃ / min, air cooling to room temperature after pre-aging) → first cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 50%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.8℃ / min, air cooling directly after cooling to the minimum temperature) → second cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 50%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.8℃ / min, air cooling directly after cooling to the minimum temperature) → second cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 50%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%) The deformation process involved three stages: deformation amount (15%), cooling aging temperature range (500→350℃), cooling rate (0.8℃ / min), and air cooling after cooling to the minimum temperature. This was followed by a third cold rolling process (deformation temperature: room temperature, deformation amount: 40%, pass deformation amount: 10%, deformation method: unidirectional synchronous rolling) → isothermal aging + cooling aging (isothermal temperature: 380℃, heating rate: 150℃ / min, time: 2h, then directly heating at a rate of 150℃ / min to the maximum cooling aging temperature for cooling aging, cooling aging temperature range: 500→400℃, cooling rate: 0.8℃ / min, and air cooling after cooling to the minimum temperature). Finally, the microhardness, electrical conductivity, and tensile properties of the typical aged alloy were characterized.

[0067] Example 8

[0068] The difference from Example 1 is that the process involves a first cold rolling + cooling aging process (deformation temperature: room temperature, deformation amount: 50%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 1.1℃ / min, followed by direct air cooling after cooling to the minimum temperature) → a second cold rolling + cooling aging process (deformation temperature: room temperature, deformation amount: 50%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.3℃ / min). n. After cooling to the minimum temperature, the alloy is directly air-cooled → third cold rolling (deformation temperature: room temperature, deformation amount: 40%, deformation per pass: 10%, deformation method: unidirectional synchronous rolling) → isothermal aging + cooling aging (isothermal temperature: 380℃, heating rate: 150℃ / min, time: 2h, then directly heating at a rate of 150℃ / min to the highest cooling aging temperature for cooling aging, cooling aging temperature range: 500→400℃, cooling rate: 0.8℃ / min, after cooling to the minimum temperature, the alloy is directly air-cooled). Finally, the microhardness, electrical conductivity and tensile properties of the typical aged alloy are characterized.

[0069] Example 9

[0070] The difference from Example 1 lies in the following process: a third cold rolling (deformation temperature: room temperature, deformation amount: 40%, per pass deformation amount: 10%, deformation method: unidirectional synchronous rolling) → isothermal aging + cooling aging (isothermal temperature: 380℃, heating rate: 150℃ / min, time: 2h, then directly heating at a rate of 150℃ / min to the highest cooling aging temperature for cooling aging, cooling aging temperature range: 500→350℃, cooling rate: 0.3℃ / min, after cooling to the lowest temperature, directly air cooling). Finally, the microhardness, electrical conductivity, and tensile properties of the typical aged alloy were characterized.

[0071] Comparative Example 1

[0072] The difference from Example 1 is that only a first-stage pre-aging treatment (480℃ / 15min) is performed, followed by air cooling to room temperature, then a first cold rolling + cooling aging process (deformation temperature: room temperature, deformation amount: 50%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.8℃ / min, air cooling is performed directly after cooling to the minimum temperature) → a second cold rolling + cooling aging process (deformation temperature: room temperature, deformation amount: 50%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃). The process involved three stages: 0℃, cooling rate: 0.8℃ / min, followed by air cooling after reaching the minimum temperature; third cold rolling (deformation temperature: room temperature, deformation amount: 40%, per pass deformation amount: 10%, deformation method: unidirectional synchronous rolling); isothermal aging + cooling aging (isothermal temperature: 380℃, heating rate: 150℃ / min, time: 2h, then directly heating at a rate of 150℃ / min to the maximum cooling aging temperature for cooling aging, cooling aging temperature range: 500→400℃, cooling rate: 0.8℃ / min, followed by air cooling after reaching the minimum temperature). Finally, the microhardness, electrical conductivity, and tensile properties of the typical aged alloy were characterized.

[0073] Comparative Example 2

[0074] The difference from Example 1 is that the second cold rolling and second cooling aging are not performed. Instead, a multi-stage pre-aging treatment (three-stage pre-aging: 480℃ / 15min + 410℃ / 15min + 360℃ / 15min, heating rate: 150℃ / min, followed by air cooling to room temperature) → first cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 50%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.8℃ / min) is used. The process involved several steps: first, isothermal aging to the minimum temperature followed by direct air cooling; then, a third cold rolling process (deformation temperature: room temperature, deformation amount: 40%, per pass deformation amount: 10%, deformation method: unidirectional synchronous rolling); second, isothermal aging followed by cooling aging (isothermal temperature: 380℃, heating rate: 150℃ / min, time: 2h, then directly heating at a rate of 150℃ / min to the maximum cooling aging temperature for cooling aging, cooling aging temperature range: 500→400℃, cooling rate: 0.8℃ / min, and air cooling after cooling to the minimum temperature). Finally, the microhardness, electrical conductivity, and tensile properties of typical aged alloys were characterized.

[0075] Comparative Example 3

[0076] The difference from Example 1 is that the third cooling aging is not performed. Instead, a multi-stage pre-aging treatment is used (three-stage pre-aging: 480℃ / 15min + 410℃ / 15min + 360℃ / 15min, heating rate: 150℃ / min, followed by air cooling to room temperature) → first cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 50%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.8℃ / min, followed by direct air cooling after cooling to the lowest temperature). →Second cold rolling + cooling aging (deformation temperature: room temperature, deformation amount: 50%, deformation method: unidirectional synchronous rolling, deformation per pass: 15%, cooling aging temperature range: 500→350℃, cooling rate: 0.8℃ / min, air cooling directly after cooling to the minimum temperature) →Third cold rolling (deformation temperature: room temperature, deformation amount: 40%, deformation per pass: 10%, deformation method: unidirectional synchronous rolling) →Isothermal aging + cooling aging (isothermal temperature: 380℃, heating rate: 150℃ / min, time: 2h, then air cooling directly). Finally, the microhardness, electrical conductivity and tensile properties of the typical aged alloy were characterized.

[0077] Performance testing:

[0078] Dislocation density: The dislocation density in the alloy matrix was measured using XRD on an Empyrean diffractometer.

[0079] β'-Cu4Ti precipitate phase and its size: The microstructure was characterized by TEM on a JEM-F200 transmission electron microscope.

[0080] Spacing between adjacent precipitate particles of various sizes: characterized by TEM structure on a JEM-F200 transmission electron microscope.

[0081] Hardness: Tested on EAM-3A-500 microhardness scale, with 10 values ​​measured each time and the average value taken.

[0082] Electrical conductivity: Tested using a SIGMATEST 2.070 eddy current conductivity meter, with 10 values ​​measured each time and the average value taken. Tensile strength and yield strength: Tested on an AG-Xplus tensile testing machine according to international standard E8 / E8M-16a. Elongation: Tested according to international standard GB / T 228.1-2021.

[0083] Data for all the above embodiments and comparative examples are shown in Tables 1 to 3.

[0084] Table 1. Hardness and electrical conductivity of multi-stage pre-aged and tertiary cold-rolled alloys.

[0085]

[0086] Table 2 Tensile and electrical properties of Cu-Ti alloys in their final state

[0087]

[0088]

[0089] Table 3. Spacing and dislocation density between adjacent particles of precipitates of various sizes

[0090]

[0091] Based on the above design concept, the hardness of Examples 1 and 2 after three-stage pre-aging control is 250 HV and 248 HV, respectively, and the electrical conductivity is 9.1% IACS and 8.9% IACS, respectively. However, the hardness of Examples 3 and 4 after two-stage pre-aging control is 247 HV and 246 HV, respectively, and the electrical conductivity also decreases to 8.8% IACS and 8.7% IACS, respectively. However, the hardness of the alloys in Examples 5 and 6 after two-stage pre-aging control can reach 249 HV and 248 HV, respectively, and the electrical conductivity is similar to that of Examples 1 and 2, at 9.0% IACS and 8.8% IACS, respectively, as shown in Table 1. It can be seen that after multi-stage pre-aging control, not only do multi-scale precipitates precipitate in the alloy matrix, but the size distribution, number density, and distribution characteristics of the precipitates are also different, leading to different properties. At the same time, this also provides the possibility for further constructing multi-scale precipitates with different coupling distribution characteristics with dislocations through deformation non-isothermal aging. Because multi-scale precipitates have already formed in the alloy matrix, they can effectively pin dislocations during subsequent cold rolling deformation, resulting in better and more uniform dislocation dispersion within the matrix. This allows for the proper growth of the existing multi-scale precipitates during the subsequent cooling aging after the first cold rolling deformation, and also induces the formation of more precipitates of different sizes, leading to a greater variety of precipitate sizes and a more uniform distribution. This increased size and uniform distribution of the precipitates makes it possible for the alloy to undergo further cold rolling and cooling aging with larger deformation amounts. Figure 2 and 3 It can be seen that during the cooling and aging process of the alloy after secondary cold rolling in Example 1, the hardness distribution of the alloy changed significantly with the decrease of the cooling and aging temperature. However, only the hardness at 470℃ exceeded the initial state, while the hardness at other states decreased. This is likely due to the synergistic effect of the strength reduction caused by dislocation annihilation and the precipitation strengthening induced by precipitation. At 470℃, the overall dislocation annihilation was relatively small, and further precipitation led to an overall increase in alloy hardness. However, as the cooling and aging temperature decreased further, dislocation annihilation gradually intensified, while the number of precipitated phases was limited. In addition, the contribution of precipitation strengthening caused by the coarsening of some coarse precipitated phases weakened, which inevitably led to a decrease in alloy hardness. Furthermore, it is worth emphasizing that the different particle sizes and distribution densities inevitably lead to differences in hardness in micro-regions. Ultimately, high-hardness micro-regions and low-hardness micro-regions will appear in the alloy matrix, resulting in a large measured hardness distribution range rather than fluctuations within the error range. At the same time, the conductivity of the alloy treated in this example also showed different variation patterns, such as Figure 3As shown, with the decrease in cooling aging temperature, the conductivity first decreased from the initial 15% IACS to 14% IACS, and then gradually increased, finally reaching a maximum of about 19.5% IACS when the cooling aging temperature decreased to 350℃. This indicates that in the initial cooling aging stage of the alloy, although dislocation annihilation and precipitation of the precipitate phase are beneficial to the increase in conductivity, the distribution characteristics of the precipitate phase and its coupling characteristics with dislocations have a significant impact on electron transport. For example, the micro-regions with coarse particle distribution are initially conducive to electron transport due to their low solute element concentration. However, due to the severe dislocation pile-up around them during cold rolling deformation, the solute elements in the matrix will preferentially promote the further growth of the coarse precipitate phase under the action of dislocations in the early stage of aging. When the precipitate phase grows to a certain extent, it is not conducive to electron transport. At this time, the precipitation of the precipitate phase in other regions leads to matrix purification, but the electron transport capacity in these micro-regions still cannot exceed the electron transport capacity of the micro-regions near the coarse precipitate phase, which will eventually lead to a decrease in the overall conductivity of the alloy. However, as the alloy is further cooled and aged, the number of precipitated phases in the matrix gradually increases and dislocations gradually annihilate, which inevitably causes the overall conductivity of the alloy to begin to increase again, eventually reaching a maximum value of about 19.5% IACS at 350℃.

[0092] Compared with the alloy treated in Example 1, the alloy treated in Example 3 showed a certain degree of change in hardness during cooling aging in the secondary cold-rolled state, such as... Figure 4 As shown in the figure, as the cooling aging temperature decreases, the hardness at 470℃ is consistently higher than the initial state. Even at 450℃, the alloy hardness remains high, with the highest hardness still exceeding the initial state. This indicates that the multi-scale precipitated phases in the alloy matrix after this multi-stage pre-aging process differ significantly from those in Example 1 after the initial cold rolling deformation and cooling aging treatment. This difference leads to different age-hardening behaviors in the secondary cold-rolled alloy sheet during cooling aging. With further decreases in cooling aging temperature, the alloy hardness decreases somewhat; however, only when the temperature drops below 390℃ does the overall alloy hardness fall below the initial state. Figure 4 As shown. For the alloy treated in this embodiment, its conductivity also exhibits the same pattern of initially decreasing slightly at 470°C, then rapidly increasing, and finally reaching its maximum value of approximately 20% IACS when the temperature drops to 350°C. Figure 5 As shown.

[0093] Furthermore, if the secondary cold-rolled alloy regulated in Example 5 is subjected to cooling aging, such as... Figure 6As shown, it can be observed that because the second-stage temperature during the two-stage pre-aging process in this embodiment is relatively low, the multi-scale effect of the precipitate phase formed during the first cold rolling + cooling process is not significant. Therefore, the hardness of the secondary cold-rolled alloy after the control in Example 5 decreases directly with the cooling process. This indicates that due to the low second-stage temperature during the initial pre-aging process, only a precipitate phase of approximately one scale is formed in the matrix. The disappearance of the multi-scale effect causes the secondary cold-rolled alloy to exhibit a direct decrease in hardness with the cooling process. Furthermore, according to... Figure 7 The conductivity variation pattern shown reveals that during the initial aging stage, although the conductivity decreases slightly, the decrease is very small, essentially maintaining the original level. Subsequently, as the temperature drops below 470℃, the conductivity gradually begins to increase, finally reaching its highest value of approximately 20% IACS when the temperature drops to 350℃. This demonstrates that different multi-stage pre-aging processes, due to the different sizes of the precipitated phases formed, significantly alter the subsequent precipitation, coarsening, and coupling distribution with dislocations, thus directly affecting the alloy's hardness and conductivity.

[0094] It is precisely because the above-mentioned technical route can induce an increase in the size of the precipitate phase and its uniform and dispersed distribution that the alloy can undergo a third cold rolling after a second cold rolling and temperature-controlled aging. The hardness and electrical conductivity of the alloy after cold rolling are shown in Table 1. Table 1 shows that the alloy's hardness and electrical conductivity have significantly increased at this point, especially the electrical conductivity, which is significantly higher than that of Cu-Ti alloys with tensile strengths above 1000 MPa produced domestically and internationally, even in the cold-rolled state. Furthermore, due to the formation of more pronounced multi-scale precipitate phases within the alloy matrix, the hardness of the alloy matrix is ​​distributed within a certain range. For example, the hardness of the alloy in the third cold-rolled state corresponding to Example 1 is distributed between 307-330 HV. This is mainly due to the large differences in the size of the precipitate phases, leading to different contributions of precipitation strengthening. However, this multi-scale precipitate phase distribution does not result in a similar characteristic in the electrical conductivity, i.e., a distribution within a certain range. The reason is that after the formation of multi-scale precipitated phases, the alloy matrix is ​​effectively purified. Although the degree of matrix purification varies with the change of precipitated phase scale, electrons will choose to pass through areas with lower resistance when passing through the matrix. The stable conductivity value of the alloy in the third cold-rolled state in the same embodiment indicates that the alloy has micro-regions with the same comprehensive influence on electron transport, including the degree of matrix purification, multi-scale precipitated phases and dislocation coupling distribution.

[0095] Although the overall performance of the third-stage cold-rolled alloy is already good, this invention innovatively proposes further isothermal aging combined with non-isothermal aging to synergistically improve its strength, plasticity, and electrical conductivity. The key purpose of this regulation is that the precipitates formed within the third-stage cold-rolled alloy matrix exhibit significant differences in size and dislocation pinning ability; large-scale precipitates have weaker pinning ability, while small precipitates have stronger pinning ability. Directly performing high-temperature isothermal aging or cooling aging from high to low temperatures, while inducing further precipitation and purifying the matrix to significantly improve electrical conductivity, also leads to a rapid decrease in dislocation density. Ultimately, while improving conductivity, this results in a significant decrease in alloy strength. Therefore, by first performing low-temperature isothermal aging for a certain period based on the multi-scale precipitate-dislocation coupling distribution characteristics of the third-stage cold-rolled alloy, not only will the dislocation density not decrease rapidly, but more precipitates will also be induced, thus better pinning dislocations and preventing their rapid annihilation. Based on isothermal aging control, further cooling aging at appropriate rates and within appropriate temperature ranges can further promote the precipitation of precipitated phases in alloy matrices with already low precipitation kinetics. Moreover, since the dislocation annihilation rate can also be effectively controlled after reasonable control of the cooling aging rate, the overall performance of the alloy will inevitably be significantly improved. Just as... Figure 8 The hardness changes of Examples 1, 3, and 5 after the third cold-rolled state under isothermal and cooling aging processes show significant differences in hardness among the three multi-stage pre-aging alloys. There are also some differences in electrical conductivity, although the conductivity has been significantly improved, reaching a maximum of 22.8% IACS. Furthermore, the tensile properties also differ. Although the tensile strength did not reach 1000 MPa, the tensile strength of Example 1 is close to 1000 MPa, and the corresponding elongation is also high, significantly higher than the elongation reported in the literature for alloys of similar strength levels. With changes in the cooling rate used for cooling aging after isothermal aging, such as… Figure 9 As shown, after the alloys were subjected to a relatively rapid cooling and aging process, the hardness distribution range of the alloys in the various examples remained basically consistent, all ranging from 290 to 330 HV. Furthermore, according to Table 2, the tensile strength of the alloys developed in Examples 2 and 4 both exceeded 1000 MPa, and their elongation and electrical conductivity were also excellent, with an elongation of up to 8.3% and an electrical conductivity around 21% IACS, demonstrating very superior overall performance.

[0096] In summary, this invention, through multi-stage pre-aging and subsequent multiple deformation non-isothermal heat treatments to synergistically regulate the precipitation of multi-scale precipitates in a typical Cu-Ti alloy, not only precipitates multi-scale phases but also ensures that these phases couple with dislocations, thereby synergistically improving the alloy's strength, plasticity, and conductivity. The high-strength, high-ductility, and high-conductivity Cu-Ti alloy material and its preparation method developed in this invention can effectively meet the urgent needs of many high-tech fields, such as electronics, aerospace, instrumentation, and home appliances, for manufacturing typical components requiring high strength, high conductivity, and high plasticity copper alloys. Therefore, this preparation method is not only highly suitable for many high-tech fields, especially those with specific requirements for high-strength, high-conductivity novel copper alloys, but also provides a good solution to common problems encountered in the manufacturing of complex-shaped parts with high requirements for strength, conductivity, and plasticity, such as poor machinability and conductivity. Furthermore, this preparation technology also has guiding significance for the further development, processing, and application of high-strength, high-conductivity copper alloys and other similar metallic materials in other fields. Copper alloy processing enterprises should pay attention to this alloy and its preparation process to promote and apply it as soon as possible.

[0097] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0098] In this application, the Cu-Ti alloy exhibits optimized distribution of multi-scale precipitated phases without affecting its fundamental properties. These precipitated phases include microstructures with sizes ranging from 3 to 7 nm, 8 to 12 nm, and 13 to 20 nm. They collectively act on the alloy matrix, resulting in significantly improved strength, plasticity, and electrical conductivity in the Cu-Ti alloy. This is because precipitated phases of different scales can form a complex reinforcing network within the Cu-Ti alloy. This application utilizes the presence of precipitated phases of different scales in the Cu-Ti alloy and their combined effect on dislocations to effectively promote the regulation and optimization of dislocation movement, while simultaneously reducing electron scattering in the Cu-Ti alloy matrix. This achieves a synergistic improvement in strength, plasticity, and electrical conductivity, representing a significant improvement and breakthrough compared to existing Cu-Ti alloy materials.

[0099] The above are merely embodiments of the present invention and are not intended to limit the invention. Those skilled in the art will recognize that the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A Cu-Ti alloy, characterized in that, The Cu-Ti alloy comprises, by mass percentage: 3.0 to 3.5 wt% Ti, ≤0.05 wt% B, ≤0.05 wt% Zr, with the balance being Cu. The Cu-Ti alloy includes β'-Cu4Ti precipitates with a size of 3-7 nm, β'-Cu4Ti precipitates with a size of 8-12 nm, and β'-Cu4Ti precipitates with a size of 13-20 nm.

2. The Cu-Ti alloy according to claim 1, characterized in that, The dislocation density of the Cu-Ti alloy is (1~4)×10 14 ·m -2 .

3. The Cu-Ti alloy according to claim 1 or 2, characterized in that, The spacing between adjacent particles of the β'-Cu4Ti precipitate phase with a size of 3-7 nm is 4-6 nm; and / or the spacing between adjacent particles of the β'-Cu4Ti precipitate phase with a size of 8-12 nm is 8-10 nm; and / or the spacing between adjacent particles of the β'-Cu4Ti precipitate phase with a size of 13-20 nm is 14-19 nm.

4. A method for preparing the Cu-Ti alloy according to any one of claims 1 to 3, characterized in that, The preparation method includes the following steps performed in sequence: batching, casting, homogenization heat treatment, hot rolling deformation, cold rolling deformation, solution quenching treatment, multi-stage pre-aging treatment, first cold rolling, first cooling aging, second cold rolling, second cooling aging, third cold rolling, isothermal aging, and third cooling aging.

5. The preparation method according to claim 4, characterized in that, The multi-stage pre-aging process is either a three-stage pre-aging process or a two-stage pre-aging process. The three-stage pre-aging process includes a first-stage pre-aging, a second-stage pre-aging, and a third-stage pre-aging, performed sequentially. The first-stage pre-aging temperature is 440–500℃, and the time is 5–30 min; the second-stage pre-aging temperature is 390–435℃, and the time is 5–30 min; the third-stage pre-aging temperature is 340–385℃, and the time is 5–30 min. The two-stage pre-aging process includes a first-stage pre-aging and a second-stage pre-aging, performed sequentially. The first-stage pre-aging is performed at a temperature of 440–500°C for 5–30 min, and the second-stage pre-aging is performed at a temperature of 390–435°C for 15–45 min. Alternatively, the first-stage pre-aging is performed at a temperature of 440–500°C for 5–30 min, and the second-stage pre-aging is performed at a temperature of 330–385°C for 25–60 min.

6. The preparation method according to claim 4, characterized in that, The temperature of the first cold rolling is 25-30℃, the total deformation is 40-60%, the deformation method is unidirectional synchronous rolling, and the deformation per pass is 5-20%; and / or the temperature of the first cooling aging is reduced from 500℃ to 350℃, the cooling rate is 0.4-0.9℃ / min, and air cooling is performed when the temperature of the first cooling aging is 350℃.

7. The preparation method according to claim 4, characterized in that, The second cold rolling temperature is 25-30℃, the total deformation is 40-60%, the deformation method is unidirectional synchronous rolling, and the deformation per pass is 5-20%; and / or the temperature of the second cooling aging is reduced from 500℃ to 350℃, the cooling rate is 0.4-0.9℃ / min, and air cooling is performed when the temperature of the second cooling aging is 350℃.

8. The preparation method according to claim 4, characterized in that, The temperature of the third cold rolling is 25-30℃, the total deformation is 35-55%, the deformation method is unidirectional synchronous rolling, and the deformation per pass is 5-15%.

9. The preparation method according to claim 4, characterized in that, The isothermal aging temperature is 350–390°C. During the process of raising the temperature to the isothermal aging temperature, the heating rate is greater than 100°C / min. After the isothermal aging is performed for 1–7 hours, the temperature is raised to the highest temperature of the third cooling aging at a rate greater than 100°C / min. The third cooling aging is performed by lowering the temperature from 500°C to 400°C at a cooling rate of 0.4–0.9°C / min. When the temperature of the third cooling aging is 400°C, air cooling is performed.

10. The preparation method according to claim 4, characterized in that, The homogenization heat treatment is performed at a temperature of 750–850°C for 0.5–6 hours; and / or the total deformation of the hot rolling deformation is 60–90%, the deformation method is unidirectional synchronous rolling, and the deformation per pass is 10–20%; and / or the cold rolling deformation is performed at a temperature of 25–30°C, and the total deformation is 40–55%; and / or The solution quenching treatment is performed at a temperature of 800–900℃ for 2–5 hours.

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