Fiber-reinforced high-strength medium-conductivity Cu-Ti alloy, preparation method and application thereof

Abstract

This invention relates to the field of copper alloy material processing technology, specifically to a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy, its preparation method, and its applications. The method includes vacuum melting, homogenization treatment, hot rolling, solution treatment, aging treatment, and cold rolling steps. This preparation process can synergistically regulate the microstructure of the Cu-Ti alloy through discontinuous precipitation during aging and cold rolling, obtaining a fibrous structure, thereby achieving simultaneous improvement in strength and conductivity. The Cu-Ti alloy prepared by the process of this invention has a strength exceeding 1000 MPa and a conductivity exceeding 20% ​​IACS, while also possessing excellent wear resistance, fatigue resistance, corrosion resistance, and good weldability and machinability. It can meet the performance requirements of high-end connectors, wires, equipment frames, busbars, plugs, and switches in the aerospace, 5G communication, smart terminal, and new energy fields.

Description

Technical Field

[0001] This invention relates to the field of copper alloy material processing technology, specifically to a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy, its preparation method, and its application. Background Technology

[0002] Cu-Ti alloys exhibit excellent strength, hardness, and elasticity, along with superior wear resistance, fatigue resistance, corrosion resistance, and good weldability and machinability—properties comparable to beryllium bronze (Cu-Be). However, Cu-Ti alloys perform better at high temperatures, and the abundant and relatively low cost of Ti makes them a potential alternative to Cu-Be alloys in the electrical industry. Therefore, Cu-Ti alloys are ideal materials for manufacturing high-end connectors, motor frames, and other high-tech applications, and are widely used in cutting-edge fields such as aerospace, 5G communications, smart terminals, and new energy.

[0003] However, when the titanium content exceeds 2.5 wt%, the alloy's conductivity drops sharply to below 15% IACS. This is mainly attributed to the solid solution strengthening effect of titanium atoms in the copper matrix—titanium atoms, as a strong solid solution element, exhibit increased lattice distortion due to the electronegativity difference between them and copper atoms (Cu: 1.90 vs Ti: 1.54), significantly increasing the probability of electron scattering. This mismatch between its electrical conductivity and mechanical properties has become a key bottleneck restricting its large-scale application.

[0004] The conventional preparation process for existing Cu-Ti alloys involves: casting → homogenization → solution treatment → cold rolling → aging. This method can increase the tensile strength of the alloy to over 1000 MPa. However, this strengthening mechanism also leads to a deterioration in electrical conductivity: the dislocation network introduced by cold deformation increases the resistance to electron transport, while residual solute atoms during aging further exacerbate electron scattering. Experimental data show that even with optimized staged aging treatment, the conductivity of Cu-Ti alloys still struggles to exceed 15% IACS, significantly falling short of the industrial application requirement of over 20% IACS.

[0005] Therefore, a new heat treatment process for Cu-Ti alloys needs to be invented to ensure that the overall performance of Cu-Ti alloys meets the requirements. Summary of the Invention

[0006] Based on this, the present invention provides a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy based on discontinuous precipitation regulation, its preparation method and application through multi-stage deformation heat treatment. This method achieves simultaneous improvement in strength and conductivity by synergistically regulating the microstructure of Cu-Ti alloy through aging precipitation and cold rolling, thus solving the problem that the conductivity of Cu-Ti alloy will drop sharply when the titanium content exceeds 2.5wt%.

[0007] This application first provides a method for preparing a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy. The main steps of this method are: vacuum casting → homogenization treatment → hot rolling → solution treatment → aging treatment → cold rolling. The specific steps are as follows:

[0008] S1. Vacuum casting: The prepared Cu-Ti alloy composition is placed in a vacuum induction furnace for melting, and then cast into a mold to obtain an alloy ingot;

[0009] S2. Homogenization treatment: The obtained alloy ingot is homogenized to eliminate internal component segregation and microstructure inhomogeneity.

[0010] S3. Hot rolling: The alloy ingot after homogenization treatment is directly hot rolled to initially shape the alloy material, eliminate casting defects, and refine the grains.

[0011] S4. Solution treatment: The hot-rolled alloy material is subjected to solution treatment to obtain a supersaturated solid solution, which prepares the alloy for full aging.

[0012] S5. Aging treatment: The supersaturated solid solution alloy material after solid solution treatment is aged to allow a large number of discontinuous precipitates to be formed, resulting in a discontinuous precipitate structure. This allows solute atoms to be precipitated from the matrix to the maximum extent, thereby improving the purity of the copper matrix and thus enhancing the conductivity of the alloy.

[0013] S6. Cold rolling: Cold rolling is performed on the aged alloy material to cause the discontinuous precipitate phase to undergo a stretching and / or crushing process, thereby adjusting the size, morphology and distribution of the discontinuous precipitate, transforming it into a fibrous structure, and finally obtaining a fiber-reinforced high-strength medium-conductivity Cu-Ti alloy based on the regulation of discontinuous precipitation.

[0014] As some embodiments of this application, in step S1, the composition of the Cu-Ti alloy component is: pure titanium particles, niobium particles, and electrolytic copper.

[0015] As some embodiments of this application, in step S1, the specific process of vacuum casting is as follows: evacuate to below 10 Pa, fill with argon gas for protection, melt at 1250℃~1300℃, hold for 10min~20min, and cast in a graphite mold at a casting temperature of 1150℃~1200℃.

[0016] As some embodiments of this application, in step S1, the mass percentage content of the alloy ingot obtained is as follows: Ti content: 2.5wt%~3.5wt%, Nb content: 0.3wt%~1wt%, and the balance is Cu.

[0017] As some embodiments of this application, in step S2, the homogenization treatment temperature is 850℃~950℃ and the time is 2h~5h.

[0018] As some embodiments of this application, in step S3, the temperature of hot rolling is 820°C to 880°C, the deformation per pass is 20% to 25%, and the total deformation is 60% to 80%.

[0019] As some embodiments of this application, in step S4, the solution treatment temperature is 850℃~950℃ and the time is 1h~2h.

[0020] As some embodiments of this application, in step S5, the aging treatment temperature is 500℃~600℃ and the time is 20h~40h.

[0021] As some embodiments of this application, in step S6, the deformation amount of each cold rolling pass is 5% to 10%, and the total deformation amount is 60% to 98%.

[0022] This invention also provides a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy prepared using any of the above methods.

[0023] This invention also applies the aforementioned fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy to aerospace, 5G communication, smart terminals, and new energy fields, specifically in products such as connectors, wires, equipment frames (e.g., motor frames), busbars, plugs, and switches. Utilizing its high strength (≥1000MPa), excellent conductivity (≥20%IACS), wear resistance, fatigue resistance, corrosion resistance, and good weldability and machinability, it meets the comprehensive performance requirements of materials under complex working conditions.

[0024] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0025] 1. The alloy ingot undergoes homogenization, hot rolling, and solution treatment sequentially, followed by aging treatment to obtain a large number of discontinuous precipitate structures. This allows solute atoms to precipitate from the matrix to the maximum extent, thereby improving the purity of the copper matrix and enhancing the alloy's conductivity. Finally, a cold rolling process is added to adjust the size, morphology, and distribution of the discontinuous precipitates. The discontinuous precipitates undergo a gradual transformation from a lamellar to a fibrous structure, with a decrease in the average interlamellar spacing, optimizing the uniformity and continuity of the interlamellar spacing. The interaction between the fibrous discontinuous precipitates and dislocations after the fibrous transformation has a significant strengthening effect on the alloy. Furthermore, the cold rolling process causes relatively little damage to the distribution of the precipitates, and the scattering effect of increased dislocation density on electron migration is compensated by the fibrous distribution of the discontinuous precipitate structure; therefore, the conductivity does not decrease during this process.

[0026] 2. By controlling the precipitation and distribution of discontinuous deposits, a fibrous microstructure can be obtained, fully leveraging the potential of Cu-Ti alloys and overcoming the inverted strength-conductivity relationship in Cu-Ti alloys. A high-strength (over 1000 MPa) Cu-Ti alloy with excellent conductivity (over 20% IACS) was prepared. This material also possesses excellent wear resistance, fatigue resistance, corrosion resistance, and good weldability and machinability. It can meet the performance requirements of high-end connectors, motor frames, and other high-tech application products in cutting-edge fields such as aerospace, 5G communications, smart terminals, and new energy. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 The image shows the SEM image of the Cu-3.2Ti-0.3Nb alloy described in Example 1 after aging treatment and cold rolling to 90%.

[0029] Figure 2 The image shows the SEM image of the Cu-3.2Ti-0.3Nb alloy described in Example 2 after aging treatment and cold rolling to 83%.

[0030] Figure 3 The image shows the SEM image of the Cu-3.2Ti-0.3Nb alloy described in Example 3 after aging treatment and cold rolling to 76%.

[0031] Figure 4 The image shown is a TEM image of the Cu-2.5Ti-0.5Nb alloy described in Example 4 after aging treatment and cold rolling to 97%. Detailed Implementation

[0032] The technical solution of the present invention will be further described below through specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0033] Example 1: This example describes a method for preparing a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy. The specific steps are as follows:

[0034] S1. Vacuum Casting: Electrolytic copper, pure titanium particles, and niobium particles (an auxiliary element) are used to formulate a Cu-Ti alloy composition. The formulated Cu-Ti alloy composition is placed in a vacuum induction furnace for melting. The furnace is evacuated to 5 Pa, protected with argon gas, and the melting temperature is 1300℃. The mixture is held at this temperature for 15 minutes, then cast into a graphite mold at a casting temperature of 1200℃ to obtain an alloy ingot. The alloy ingot's composition by mass percentage is as follows: Ti content: 3.2 wt%, Nb content: 0.3 wt%, with the balance being copper.

[0035] S2. Homogenization treatment: The homogenization temperature is 900℃ and the time is 2h.

[0036] S3. Hot rolling: The hot rolling temperature is 850℃, the deformation per pass is 20%, and the total deformation is 70%.

[0037] S4. Solution treatment: The solution treatment temperature is 900℃ and the time is 1 hour.

[0038] S5. Aging treatment: The aging treatment temperature is 525℃ and the time is 20h.

[0039] S6. Cold rolling: The deformation amount of each cold rolling pass is 10%, and the total deformation amount is 90%.

[0040] After aging treatment, the alloy material exhibits a large amount of discontinuous precipitates, resulting in a typical layered structure. Following cold rolling, the discontinuous precipitates undergo stretching and even breakage, optimizing the uniformity and continuity of the interlamellar spacing and further transforming into a fibrous structure.

[0041] The SEM image of the material after 90% cold rolling is shown below. Figure 1 As shown, from Figure 1 The discontinuous precipitates underwent significant fragmentation and redistribution, leading to optimized uniformity and continuity of the interlamellar spacing and the formation of a fibrous morphology. The alloy's excellent mechanical properties are attributed to the interaction between the discontinuous precipitates and dislocations after the fibrous transformation. The improved electrical conductivity is attributed to the abundant precipitation of the discontinuous precipitates, which reduces the solid concentration of solute atoms in the matrix. Simultaneously, the fibrous distribution of the discontinuous precipitates further reduces the scattering effect of electron migration.

[0042] Comparative Example: The same Cu-Ti alloy composition as in Example 1 was processed according to the conventional process of vacuum casting → hot rolling → homogenization treatment → solution treatment → cold rolling → aging treatment. The difference from Example 1 is that in the comparative example, the cold rolling was performed before the aging process, and the optimal parameters of the process were selected to obtain the comparative alloy.

[0043] Example 2: This example describes a method for preparing a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy. The specific steps are as follows:

[0044] S1. Vacuum Casting: Electrolytic copper, pure titanium particles, and niobium particles (an auxiliary element) are used to formulate a Cu-Ti alloy composition. The formulated Cu-Ti alloy composition is placed in a vacuum induction furnace for melting. The furnace is evacuated to 5 Pa, protected with argon gas, and the melting temperature is 1300℃. The mixture is held at this temperature for 15 minutes, then cast into a graphite mold at a casting temperature of 1200℃ to obtain an alloy ingot. The alloy ingot's composition by mass percentage is as follows: Ti content: 3.2 wt%, Nb content: 0.3 wt%, with the balance being copper.

[0045] S2. Homogenization treatment: The homogenization temperature is 900℃ and the time is 2h.

[0046] S3. Hot rolling: The hot rolling temperature is 850℃, the deformation per pass is 20%, and the total deformation is 70%.

[0047] S4. Solution treatment: The solution treatment temperature is 900℃ and the time is 1 hour.

[0048] S5. Aging treatment: The aging treatment temperature is 525℃ and the time is 20h.

[0049] S6. Cold rolling: The deformation amount per pass in cold rolling is 8%, and the total deformation amount is 83%.

[0050] The material after cold rolling (83%) was tested, and its SEM image is shown below. Figure 2 As shown, from Figure 2 The discontinuous precipitates underwent significant fragmentation and redistribution, leading to optimized uniformity and continuity of the interlamellar spacing and the formation of a fibrous morphology. The alloy's excellent mechanical properties are attributed to the interaction between the discontinuous precipitates and dislocations after the fibrous transformation. The improved electrical conductivity is attributed to the abundant precipitation of the discontinuous precipitates, which reduces the solid concentration of solute atoms in the matrix. Simultaneously, the fibrous distribution of the discontinuous precipitates further reduces the scattering effect of electron migration.

[0051] Example 3: This example describes a method for preparing a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy. The specific steps are as follows:

[0052] S1. Vacuum Casting: Electrolytic copper, pure titanium particles, and niobium particles (an auxiliary element) are used to prepare a Cu-Ti alloy composition. The prepared Cu-Ti alloy composition is placed in a vacuum induction furnace for melting. The furnace is evacuated to 5 Pa, protected with argon gas, and the melting temperature is 1300℃. The mixture is held at this temperature for 15 minutes, then cast into a graphite mold at a casting temperature of 1200℃ to obtain an alloy ingot. The alloy ingot's composition by mass percentage is: Ti: 3.2 wt%, Nb: 0.3 wt%, with the balance being copper.

[0053] S2. Homogenization treatment: The homogenization temperature is 900℃ and the time is 2h.

[0054] S3, Hot Rolling: The hot rolling temperature is 850℃, the deformation per pass is 25%, and the total deformation is 70%.

[0055] S4. Solution treatment: The solution treatment temperature is 900℃ and the time is 1 hour.

[0056] S5. Aging treatment: The aging treatment temperature is 525℃ and the time is 20h.

[0057] S6. Cold rolling: The deformation amount per pass in cold rolling is 7%, and the total deformation amount is 76%.

[0058] The SEM image of the material after cold rolling to 76% is shown below. Figure 3 As shown, from Figure 3 The discontinuous precipitates underwent significant fragmentation and redistribution, leading to optimized uniformity and continuity of the interlamellar spacing and the formation of a fibrous morphology. The alloy's excellent mechanical properties are attributed to the interaction between the discontinuous precipitates and dislocations after the fibrous transformation. The improved electrical conductivity is attributed to the abundant precipitation of the discontinuous precipitates, which reduces the solid concentration of solute atoms in the matrix. Simultaneously, the fibrous distribution of the discontinuous precipitates further reduces the scattering effect of electron migration.

[0059] Example 4: This example describes a method for preparing a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy. The specific steps are as follows:

[0060] S1. Vacuum Casting: Electrolytic copper, pure titanium particles, and niobium particles (an auxiliary element) are used to prepare a Cu-Ti alloy composition. The prepared Cu-Ti alloy composition is placed in a vacuum induction furnace for melting. The furnace is evacuated to 10 Pa, protected with argon gas, and the melting temperature is 1250℃. The mixture is held at this temperature for 12 minutes, then cast into a graphite mold at a casting temperature of 1180℃ to obtain an alloy ingot. The alloy ingot's composition by mass percentage is: Ti: 2.5 wt%, Nb: 0.5 wt%, with the balance being copper.

[0061] S2. Homogenization treatment: The homogenization temperature is 900℃ and the time is 2h.

[0062] S3, Hot Rolling: The hot rolling temperature is 850℃, the deformation per pass is 25%, and the total deformation is 80%.

[0063] S4. Solution treatment: The solution treatment temperature is 900℃ and the time is 1 hour.

[0064] S5. Aging treatment: The aging treatment temperature is 550℃ and the time is 25h.

[0065] S6. Cold rolling: The deformation amount of each cold rolling pass is 10%, and the total deformation amount is 97%.

[0066] The material after 97% cold rolling was tested, and its TEM image is shown below. Figure 4 As shown, from Figure 4 The discontinuous precipitates underwent significant fragmentation and redistribution, leading to optimized uniformity and continuity of the interlamellar spacing and the formation of a fibrous morphology. The alloy's excellent mechanical properties are attributed to the interaction between the discontinuous precipitates and dislocations after the fibrous transformation. The improved electrical conductivity is attributed to the abundant precipitation of the discontinuous precipitates, which reduces the solid concentration of solute atoms in the matrix. Simultaneously, the fibrous distribution of the discontinuous precipitates further reduces the scattering effect of electron migration.

[0067] Mechanical properties and electrical conductivity were tested on Examples 1-4 and the comparative examples, and the results are shown in Table 1 below.

[0068] Table 1. Mechanical properties and electrical conductivity test results:

[0069]

[0070] Analysis of the data in Table 1 shows that the fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy prepared using the method of discontinuous precipitation regulation proposed in this application can fully utilize the potential of Cu-Ti alloys and overcome the inverted relationship between strength and conductivity in Cu-Ti alloys. A high-strength (over 1000 MPa) Cu-Ti alloy with excellent conductivity (over 20% IACS) is prepared. This material also possesses excellent wear resistance, fatigue resistance, corrosion resistance, and good weldability and machinability. It can meet the performance requirements of high-end connectors, motor frames, and other high-tech application products in cutting-edge fields such as aerospace, 5G communication, smart terminals, and new energy.

[0071] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0072] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy, characterized in that, The steps are as follows: S1. Vacuum casting: The prepared Cu-Ti alloy composition is placed in a vacuum induction furnace and melted under an argon atmosphere. Then, it is cast into a mold to obtain an alloy ingot. The composition of the alloy ingot is in the following mass percentage range: Ti content: 2.5wt%~3.5wt%, Nb content: 0.3wt%~1wt%; balance is Cu. S2. Homogenization treatment: The obtained alloy ingot is subjected to homogenization treatment; S3. Hot rolling: The alloy ingot after homogenization is directly subjected to hot rolling. S4. Solution treatment: The hot-rolled alloy material is subjected to solution treatment to obtain a supersaturated solid solution. S5. Aging treatment: The alloy material after solution treatment is subjected to aging treatment to induce the precipitation of a large number of discontinuous precipitates, thereby obtaining a discontinuous precipitate structure; the aging treatment temperature is 500℃~600℃ and the time is 20h~40h. S6. Cold rolling: The alloy material after aging treatment is subjected to cold rolling. The deformation amount of each cold rolling pass is 5% to 10%, and the total deformation amount is 60% to 98%. This causes the discontinuous precipitate phase to undergo a stretching and / or crushing process, thereby adjusting the size, morphology and distribution of the discontinuous precipitate and transforming it into a fibrous structure.

2. The method for preparing a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy according to claim 1, characterized in that, In step S1, the Cu-Ti alloy raw material consists of pure titanium particles, niobium particles (an auxiliary element), and electrolytic copper.

3. The method for preparing a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy according to claim 2, characterized in that, In step S1, the specific process of vacuum casting is as follows: evacuate to below 10 Pa, fill with argon gas for protection, melt at 1250℃~1300℃, hold for 10min~20min, and then cast in a graphite mold at a casting temperature of 1150℃~1200℃.

4. The method for preparing a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy according to claim 1, characterized in that, In step S2, the homogenization treatment temperature is 850℃~950℃, and the time is 2h~5h.

5. The method for preparing a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy according to claim 1, characterized in that, In step S3, the hot rolling temperature is 820℃~880℃, the deformation per pass is 20%~25%, and the total deformation is 60%~80%.

6. The method for preparing a fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy according to claim 1, characterized in that, In step S4, the solution treatment temperature is 850℃~950℃, and the time is 1h~2h.

7. A fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy, characterized in that, The fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy is prepared by the preparation method described in any one of claims 1 to 6.

8. The application of the fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy as described in claim 7 in the fields of aerospace, smart terminals, or new energy.

9. The application of the fiber-reinforced high-strength, medium-conductivity Cu-Ti alloy as described in claim 7 in the field of 5G communication.

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