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

Abstract

The invention relates to the technical field of copper alloy material processing, in particular to a fiber-reinforced high-strength medium-conductivity Cu-Ti alloy and a preparation method and application thereof, and the method comprises the steps of vacuum melting, homogenization treatment, hot rolling, solution treatment, aging treatment and cold rolling. According to the preparation process, the microscopic structure of the Cu-Ti alloy can be cooperatively regulated and controlled through discontinuous precipitation and cold rolling in the aging process, a fibrous structure is obtained, and therefore the strength and the electric conductivity are synchronously improved. According to the Cu-Ti alloy prepared through the preparation technology, the strength exceeds 1000 MPa, the electric conductivity exceeds 20% IACS, and meanwhile the Cu-Ti alloy has excellent wear resistance, fatigue resistance and corrosion resistance and good weldability and machinability. The performance requirements of materials for high-end connectors, wires, equipment frames, conducting bars, connectors and switches in the fields of aerospace, 5G communication, intelligent terminals and new energy can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of copper alloy material processing, and particularly relates to a fiber-reinforced high-strength medium-conductivity Cu-Ti alloy, a preparation method thereof, and an application thereof. Background Art

[0002] Cu-Ti alloys exhibit excellent strength, hardness, and elasticity, and at the same time possess excellent wear resistance, fatigue resistance, corrosion resistance, as well as good weldability and machinability. These properties are comparable to those of beryllium bronze (Cu-Be). However, Cu-Ti alloys perform better at high temperatures, and coupled with the rich resources and low cost of Ti elements, it 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 application products, and have been widely used in cutting-edge fields such as aerospace, 5G communication, intelligent terminals, and new energy.

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

[0004] The conventional preparation process steps of existing Cu-Ti series alloys are: melting and casting → homogenization → solution treatment → cold rolling → aging. This method can make the tensile strength of the alloy break through the 1000 MPa mark. However, this strengthening mechanism also brings about the deterioration of electrical conductivity: the dislocation network introduced by cold deformation increases the electron transport resistance, and the residual solute atoms during the aging process further exacerbate the electron scattering effect. Experimental data shows that even after optimized step aging treatment, the conductivity of Cu-Ti alloys is still difficult to break through 15% IACS, showing a significant gap from the standard of over 20% IACS required for industrial applications.

[0005] Therefore, it is still necessary to invent a new heat treatment process for Cu-Ti alloys to make the comprehensive properties of Cu-Ti series alloys meet 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, a multi-stage deformation heat treatment preparation method thereof, and an application thereof. This method realizes the synchronous improvement of strength and conductivity by synergistically regulating the microstructure of Cu-Ti alloys through aging precipitation and cold rolling, and solves the problem that when the titanium content in Cu-Ti alloys exceeds 2.5 wt%, the conductivity of the alloy will drop sharply.

[0007] The embodiments of the present application first provide a preparation method of a fiber-reinforced high-strength and medium-conductivity Cu-Ti alloy. The main steps of this method are: vacuum melting and casting → homogenization treatment → hot rolling → solution treatment → aging treatment → cold rolling. The specific steps are as follows: S1. Vacuum melting and casting: Put the formulated Cu-Ti alloy components into a vacuum induction furnace for melting, and then cast and form in a mold to obtain an alloy ingot. S2. Homogenization treatment: Perform homogenization treatment on the obtained alloy ingot to eliminate internal composition segregation and tissue inhomogeneity. S3. Hot rolling: Directly perform hot rolling on the alloy ingot after homogenization treatment to initially form the alloy material, break the as-cast defects, and refine the grains. S4. Solution treatment: Perform solution treatment on the alloy material after hot rolling to obtain a supersaturated solid solution and prepare for the full aging of the alloy. S5. Aging treatment: Perform aging treatment on the supersaturated solid solution alloy material after solution treatment to cause a large amount of discontinuous precipitation to occur, obtain a discontinuous precipitation structure, enable solute atoms to precipitate from the matrix to the greatest extent, thereby improving the purity of the copper matrix, and further enhancing the electrical conductivity of the alloy. S6. Cold rolling: Perform cold rolling treatment on the alloy material after aging treatment to make the discontinuous precipitation phase undergo a process of stretching and / or breaking, thereby adjusting the size, morphology, and distribution of the discontinuous precipitation, transforming it into a fibrous structure, and finally obtaining a fiber-reinforced high-strength and medium-conductivity Cu-Ti alloy based on the regulation of discontinuous precipitation.

[0008] As some embodiments of the present application, in step S1, the composition of the Cu-Ti alloy components is: pure titanium particles, niobium particles, and electrolytic copper.

[0009] As some embodiments of the present application, in step S1, the specific process of vacuum melting and casting is to evacuate to below 10 Pa, fill with argon for protection, the melting temperature is 1250 °C to 1300 °C, keep warm for 10 min to 20 min, and cast and form in a graphite mold, and the casting temperature is 1150 °C to 1200 °C.

[0010] As some embodiments of the present application, in step S1, the composition mass percentage range of the obtained alloy ingot is: Ti content: 2.5 wt% to 3.5 wt%, Nb content: 0.3 wt% to 1 wt%, and the balance is Cu.

[0011] As some embodiments of the present application, in step S2, the homogenization treatment temperature is 850 °C to 950 °C, and the time is 2 h to 5 h.

[0012] As some embodiments of the present application, in step S3, the temperature of the hot rolling treatment is 820°C to 880°C, the pass deformation is 20% to 25%, and the total deformation is 60% to 80%.

[0013] As some embodiments of the present application, in step S4, the temperature of the solution treatment is 850°C to 950°C, and the time is 1h to 2h.

[0014] As some embodiments of the present application, in step S5, the temperature of the aging treatment is 500°C to 600°C, and the time is 20h to 40h.

[0015] As some embodiments of the present application, in step S6, the pass deformation of the cold rolling treatment is 5% to 10%, and the total deformation is 60% to 98%.

[0016] The embodiment of the present invention also provides a fiber-reinforced high-strength intermediate-conductivity Cu-Ti alloy prepared by any of the above methods.

[0017] The embodiment of the present invention also applies the above fiber-reinforced high-strength intermediate-conductivity Cu-Ti alloy to fields such as aerospace, 5G communication, intelligent terminals, and new energy, and is specifically used for products such as connectors, wires, equipment frames (such as motor frames), busbars, connectors, and switches. Utilizing its high strength (≥1000MPa), excellent electrical conductivity (≥20% IACS), wear resistance, fatigue resistance, corrosion resistance, and good weldability and machinability to meet the requirements for the comprehensive performance of materials under complex working conditions.

[0018] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: 1. After the alloy ingot is subjected to homogenization treatment, hot rolling, and solution treatment in sequence, and then aging treatment, a large amount of discontinuous precipitation structure is obtained, enabling solute atoms to precipitate from the matrix to the greatest extent, thereby increasing the purity of the copper matrix and further improving the electrical conductivity of the alloy. Finally, adding a cold rolling treatment to adjust the size, morphology, or distribution of the discontinuous precipitation. The discontinuous precipitation phase undergoes a gradual transformation from a lamellar structure to a fibrous structure, and its average lamellar spacing decreases accordingly. The uniformity and continuity of the lamellar spacing are optimized. The interaction between the fibrous transformed discontinuous precipitation phase and dislocations produces a significant strengthening effect on the alloy. In addition, the cold rolling process has relatively little damage to the distribution state of the precipitated phase, and the scattering effect of the increased dislocation density on electron migration is compensated by the fibrous distribution of the discontinuous precipitation structure. Therefore, the conductivity will not decrease during this process.

[0019] 2. By regulating the precipitation and distribution of discontinuous precipitation, the fibrous tissue morphology can be obtained, which can fully exert the potential of Cu-Ti alloys and break through the inverse relationship between strength and conductivity of Cu-Ti alloys. A Cu-Ti alloy with high strength (exceeding 1000 MPa) and excellent electrical conductivity (exceeding 20% IACS) is prepared. This material also has excellent wear resistance, fatigue resistance, corrosion resistance, as well as good weldability and machinability. It can meet the performance requirements of materials for high-end connectors, motor frames and other high-tech application products in frontier fields such as aerospace, 5G communication, intelligent terminals and new energy. Description of the Drawings

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are only one embodiment of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 SEM image of the Cu-3.2Ti-0.3Nb alloy after aging treatment and 90% cold rolling in Example 1.

[0022] Figure 2 SEM image of the Cu-3.2Ti-0.3Nb alloy after aging treatment and 83% cold rolling in Example 2.

[0023] Figure 3 SEM image of the Cu-3.2Ti-0.3Nb alloy after aging treatment and 76% cold rolling in Example 3.

[0024] Figure 4 TEM image of the Cu-2.5Ti-0.5Nb alloy after aging treatment and 97% cold rolling in Example 4. Detailed Embodiments

[0025] The following further illustrates the technical solutions of the present invention through specific embodiments, but the protection scope of the present invention is not limited to the described content.

[0026] Example 1: This example is a method for preparing a fiber-reinforced high-strength and medium-conductivity Cu-Ti alloy. The specific steps are as follows: S1. Vacuum melting and casting: Electrolytic copper, pure titanium particles and niobium particles as auxiliary elements are used to determine the Cu-Ti alloy composition. The determined Cu-Ti alloy composition is put into a vacuum induction furnace for melting. The vacuum is pumped to 5 Pa, and argon gas is filled for protection. The melting temperature is 1300 °C, and it is kept warm for 15 min. It is cast into a mold in a graphite mold, and the casting temperature is 1200 °C to obtain an alloy ingot. After testing, the mass percentage content of the obtained alloy ingot components is: Ti content: 3.2 wt%, Nb content: 0.3 wt%, and the balance is copper.

[0027] S2. Homogenization treatment: The temperature of the homogenization treatment is 900 °C, and the time is 2 h.

[0028] S3. Hot rolling: The temperature of the hot rolling treatment is 850 °C, the pass deformation is 20%, and the total deformation is 70%.

[0029] S4. Solution treatment: The temperature of the solution treatment is 900 °C, and the time is 1 h.

[0030] S5. Aging treatment: The temperature of the aging treatment is 525 °C, and the time is 20 h.

[0031] S6. Cold rolling: The pass deformation of the cold rolling treatment is 10%, and the total deformation is 90%.

[0032] After the alloy material is subjected to aging treatment, a large number of discontinuous precipitates precipitate, and the microstructure exhibits a typical layered structure. After cold rolling, the discontinuous precipitate phase undergoes a process of stretching and even fragmentation, and the uniformity and continuity of the lamellar spacing are optimized, and it is further transformed into a fibrous structure.

[0033] The material after 90% cold rolling is tested, and its SEM image is as Figure 1 shown. It can be observed from Figure 1 that the discontinuous precipitation phase has undergone a significant fragmentation and redistribution process, resulting in the optimization of the uniformity and continuity of the lamellar spacing, forming the morphology of a fibrous structure. The excellent mechanical properties of the alloy are attributed to the interaction between the discontinuous precipitate phase after the fibrous transformation and the dislocations. The improvement of the alloy conductivity is attributed to the large precipitation of the discontinuous precipitation structure, which reduces the solid solution concentration of solute atoms in the matrix, and at the same time, the fibrous distribution of the discontinuous precipitation structure further reduces the scattering effect of electron migration.

[0034] Comparative example: The same Cu-Ti alloy composition as in Example 1 is processed according to the conventional process of vacuum melting and casting → hot rolling → homogenization treatment → solution treatment → cold rolling → aging treatment. The difference from Example 1 is that in the comparative example, cold rolling is before the aging process, and the optimal parameters under this process are selected to obtain the comparative example alloy.

[0035] Example 2: This example is a preparation method of a fiber-reinforced high-strength and medium-conductivity Cu-Ti alloy. The specific steps are as follows: S1. Vacuum melting and casting: Take electrolytic copper, pure titanium particles and auxiliary element niobium particles to determine the Cu-Ti alloy components. Put the determined Cu-Ti alloy components into a vacuum induction furnace for melting. Evacuate to 5 Pa, fill with argon for protection, the melting temperature is 1300 °C, keep warm for 15 min, and cast and form in a graphite mold. The casting temperature is 1200 °C to obtain an alloy ingot. After testing, the mass percentage content of the obtained alloy ingot components is: Ti content: 3.2 wt%, Nb content: 0.3 wt%, and the balance is copper.

[0036] S2. Homogenization treatment: The temperature of the homogenization treatment is 900 °C and the time is 2 h.

[0037] S3. Hot rolling: The temperature of the hot rolling treatment is 850 °C, the pass deformation amount is 20%, and the total deformation amount is 70%.

[0038] S4. Solution treatment: The temperature of the solution treatment is 900 °C and the time is 1 h.

[0039] S5. Aging treatment: The temperature of the aging treatment is 525 °C and the time is 20 h.

[0040] S6. Cold rolling: The pass deformation amount of the cold rolling treatment is 8%, and the total deformation amount is 83%.

[0041] The material after 83% cold rolling is tested. Its SEM image is as Figure 2 shown. It can be observed from Figure 2 that the discontinuous precipitation phase has undergone a significant fragmentation and redistribution process, resulting in the optimization of the uniformity and continuity of the lamellar spacing, and forming the morphology of the fiber structure. The excellent mechanical properties of the alloy are attributed to the interaction between the discontinuous precipitate phase after the fibrous transformation and the dislocations. The improvement of the alloy conductivity is attributed to the large amount of precipitation of the discontinuous precipitation structure, which reduces the solid solution concentration of solute atoms in the matrix. At the same time, the fibrous distribution of the discontinuous precipitation structure further reduces the scattering effect of electron migration.

[0042] Example 3: This example is a preparation method of a fiber-reinforced high-strength and medium-conductivity Cu-Ti alloy. The specific steps are as follows: S1. Vacuum melting and casting: Take electrolytic copper, pure titanium particles and auxiliary element niobium particles to determine the Cu-Ti alloy components. Put the determined Cu-Ti alloy components into a vacuum induction furnace for melting. Evacuate to 5 Pa, fill with argon for protection, the melting temperature is 1300 °C, keep warm for 15 min, and cast and form in a graphite mold. The casting temperature is 1200 °C to obtain an alloy ingot. After testing, the mass percentage content of the obtained alloy ingot components is: Ti content: 3.2 wt%, Nb content: 0.3 wt%, and the balance is copper.

[0043] S2. Homogenization treatment: The temperature of the homogenization treatment is 900 °C and the time is 2 h.

[0044] S3. Hot rolling: The temperature of the hot rolling treatment is 850 °C, the pass deformation is 25%, and the total deformation is 70%.

[0045] S4. Solution treatment: The temperature of the solution treatment is 900 °C and the time is 1 h.

[0046] S5. Aging treatment: The temperature of the aging treatment is 525 °C and the time is 20 h.

[0047] S6. Cold rolling: The pass deformation of the cold rolling treatment is 7% and the total deformation is 76%.

[0048] The material after 76% cold rolling is tested, and its SEM image is as Figure 3 shown. It can be observed from Figure 3 that the discontinuous precipitate phase has undergone a significant fragmentation and redistribution process, resulting in the optimization of the uniformity and continuity of the lamellar spacing and the formation of the morphology of the fibrous structure. The excellent mechanical properties of the alloy are attributed to the interaction between the discontinuous precipitate phase after the fibrous transformation and the dislocations. The improvement of the alloy conductivity is attributed to the massive precipitation of the discontinuous precipitate structure, which reduces the solid solution concentration of solute atoms in the matrix. At the same time, the fibrous distribution of the discontinuous precipitate structure further reduces the scattering effect of electron migration.

[0049] Example 4: This example is a preparation method of a fiber-reinforced high-strength and medium-conductivity Cu-Ti alloy, and the specific steps are as follows: S1. Vacuum melting and casting: Take electrolytic copper, pure titanium particles and auxiliary element niobium particles to formulate the Cu-Ti alloy components. Put the formulated Cu-Ti alloy components into a vacuum induction furnace for melting, evacuate to 10 Pa, fill with argon for protection, the melting temperature is 1250 °C, keep warm for 12 min, and cast and form in a graphite mold. The casting temperature is 1180 °C to obtain an alloy ingot. After testing, the mass percentage content of the obtained alloy ingot components is: Ti content: 2.5 wt%, Nb content: 0.5 wt%, and the balance is copper.

[0050] S2. Homogenization treatment: The temperature of the homogenization treatment is 900 °C and the time is 2 h.

[0051] S3. Hot rolling: The temperature of the hot rolling treatment is 850 °C, the pass deformation is 25%, and the total deformation is 80%.

[0052] S4. Solution treatment: The temperature of the solution treatment is 900 °C and the time is 1 h.

[0053] S5. Aging treatment: The temperature of the aging treatment is 550 °C and the time is 25 h.

[0054] S6. Cold rolling: The pass deformation of the cold rolling treatment is 10%, and the total deformation is 97%.

[0055] The material after 97% cold rolling is tested, and its TEM image is as Figure 4 shown. It can be observed from Figure 4 that the discontinuous precipitation phase has undergone a significant fragmentation and redistribution process, resulting in the optimization of the uniformity and continuity of the lamellar spacing, and the formation of the morphology of the fibrous structure. The excellent mechanical properties of the alloy are attributed to the interaction between the discontinuous precipitation phase after the fibrous transformation and the dislocations. The improvement of the alloy conductivity is attributed to the massive precipitation of the discontinuous precipitation structure, which reduces the solid solution concentration of solute atoms in the matrix. At the same time, the fibrous distribution of the discontinuous precipitation structure further reduces the scattering effect of electron migration.

[0056] The mechanical properties and conductivity of Examples 1 to 4 and the comparative examples are tested, and the results are shown in Table 1 below.

[0057] Table 1. Test table of mechanical properties and conductivity:

[0058] From the data in Table 1, it can be analyzed that the fiber-reinforced high-strength and medium-conductivity Cu-Ti alloy prepared by the preparation method of a fiber-reinforced high-strength and medium-conductivity Cu-Ti alloy based on discontinuous precipitation regulation of the present application can give full play to the potential of the Cu-Ti alloy system and break through the inverse relationship between the strength and conductivity of the Cu-Ti alloy. A Cu-Ti alloy with high strength (exceeding 1000 MPa) and excellent conductivity (exceeding 20% IACS) is prepared. This material also has excellent wear resistance, fatigue resistance, corrosion resistance, as well as good weldability and machining properties. It can meet the performance requirements of materials for high-end connectors, motor frames and other high-tech application products in frontier fields such as aerospace, 5G communication, intelligent terminals and new energy.

[0059] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, 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, it should be considered as the scope described in this specification.

[0060] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A preparation method of a fiber-reinforced high-strength intermediate-conductivity Cu-Ti alloy, characterized in that, The steps are as follows: S1. Vacuum melting and casting: Put the formulated Cu-Ti alloy components into a vacuum induction furnace, melt them under the protection of an argon gas atmosphere, and then cast them into a mold to obtain an alloy ingot. S2. Homogenization treatment: Perform homogenization treatment on the obtained alloy ingot. S3. Hot rolling: Directly perform hot rolling treatment on the homogenized alloy ingot. S4. Solution treatment: Perform solution treatment on the hot-rolled alloy material to obtain a supersaturated solid solution. S5. Aging treatment: Perform aging treatment on the alloy material after solution treatment to cause a large amount of discontinuous precipitation to occur and obtain a discontinuous precipitation structure. S6. Cold rolling: Perform cold rolling treatment on the alloy material after aging treatment to make the discontinuous precipitate phase undergo a process of stretching and / or fragmentation, thereby adjusting the size, morphology, and distribution of the discontinuous precipitation and transforming it into a fibrous structure.

2. The preparation method of a fiber-reinforced high-strength middle-conductivity Cu-Ti alloy according to claim 1, wherein, In step S1, the composition of the Cu-Ti alloy components is: pure titanium particles, auxiliary element niobium particles, and electrolytic copper.

3. The preparation method of a fiber-reinforced high-strength middle-conductivity Cu-Ti alloy according to claim 2, wherein, In step S1, the specific process of vacuum melting and casting is to evacuate to below 10 Pa, fill with argon gas for protection, the melting temperature is 1250 °C to 1300 °C, hold for 10 min to 20 min, cast into a graphite mold, and the casting temperature is 1150 °C to 1200 °C. The composition mass percentage range of the obtained alloy ingot is: Ti content: 2.5 wt% to 3.5 wt%, Nb content: 0.3 wt% to 1 wt%; the balance is Cu.

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

5. The preparation method of a fiber-reinforced high-strength middle-conductivity Cu-Ti alloy according to claim 1, wherein In step S3, the temperature of the hot rolling treatment is 820 °C to 880 °C, the pass deformation is 20% to 25%, and the total deformation is 60% to 80%.

6. A 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 °C to 950 °C, and the time is 1 h to 2 h.

7. The preparation method of a fiber-reinforced high-strength middle-conductivity Cu-Ti alloy according to claim 1, characterized in that, In step S5, the aging treatment temperature is 500 °C to 600 °C, and the time is 20 h to 40 h.

8. A method for preparing a fiber-reinforced high-strength middle-conductivity Cu-Ti alloy according to claim 1, characterized in that, In step S6, the pass deformation of the cold rolling treatment is 5% to 10%, and the total deformation is 60% to 98%.

9. A fiber-reinforced high-strength Cu-Ti alloy for medium conduction, characterized in that, This fiber-reinforced high-strength and medium-conductivity Cu-Ti alloy is prepared by the preparation method described in any one of claims 1 to 8.

10. Application of the fiber-reinforced high-strength and medium-conductivity Cu-Ti alloy described in claim 9 in the fields of aerospace, 5G communication, intelligent terminals, and new energy.

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