High-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy and preparation method thereof

Abstract

The invention belongs to the technical field of alloy preparation, and particularly relates to a high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy and a preparation method thereof. The method comprises the following steps: casting copper, a Cu-Cr intermediate alloy and a Cu-Zr intermediate alloy into a cast ingot of a copper alloy material; the alloy cast ingot is placed in a heat preservation furnace to be subjected to homogenization treatment, then hot rolling treatment, solution treatment and heat preservation are conducted, and an alloy plate is obtained; performing cold rolling deformation for the first time, and then performing aging treatment for the first time; and finally, secondary cold rolling deformation is conducted, secondary aging treatment is conducted, and the high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy is obtained. Through interaction of Cr and Zr elements and combination of multi-stage cold machining and multi-stage aging treatment, dislocation accumulation in the alloy can be further increased, it can be guaranteed that the influence of grain boundary change on the conductivity of the alloy is not greatly reduced, and the comprehensive performance of the copper alloy is further improved.

Description

Technical Field

[0001] The present application belongs to the technical field of alloy preparation, and specifically relates to a high-strength, high-conductivity, high-toughness copper-chromium-zirconium alloy and a preparation method thereof. Background Art

[0002] Copper-chromium-zirconium copper alloy not only has high strength and high conductivity, but also provides excellent thermal stability, corrosion resistance and processing performance, while maintaining good fatigue tolerance. It is widely used in automotive terminal connectors, high-density lead frames and other fields, especially in the application field of integrated circuit lead frames. However, with the rapid development of science and technology, as well as the needs of electronic product integration, lightweight and large-scale integration of integrated circuits, higher and higher requirements are put forward for the strength and conductivity of copper alloys. Especially in terms of conductivity, the lead frame plays a role in connecting the chip and the outside in the plastic package, so it is required to have good conductivity. In addition, when designing the circuit, sometimes the ground wire is connected to the base of the lead frame through the isolation wall of the chip, which requires it to have good conductivity. Some integrated circuits have a higher operating frequency. In order to reduce parasitic effects such as capacitance and inductance, the conductivity of the lead frame is required to be higher. The higher the conductivity, the smaller the impedance generated by the lead frame, and the less heat generated. Most of the high-performance copper alloy materials for high-end lead frames in my country are low-end, and high-end key products mainly rely on imports, and the self-sufficiency rate is seriously insufficient.

[0003] At present, there have been a lot of studies on Cu-Cr-Zr alloys at home and abroad. Although the mechanical properties and electrical conductivity of the alloy can be effectively optimized by adding trace elements and rare earths, this will undoubtedly greatly increase the cost. Many studies have shown that deformation heat treatment process is also an effective way to improve the performance of the alloy. Although the strength of the Cu-Cr-Zr alloys currently studied has basically reached more than 550MPa, most of the electrical conductivity is still around 80%IACS, and the elongation after fracture is basically maintained below 10%. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies of the prior art and provide a high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy and a preparation method thereof, which specifically adopts the following technical solutions: In a first aspect, the present invention provides a method for preparing a high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy, characterized in that it comprises the following steps: S1. Place copper, Cu-Cr master alloy and Cu-Zr master alloy in a vacuum medium frequency induction furnace. -2 Pa or more until the material is completely melted, the vacuum is turned off, and then a protective gas is introduced to keep the temperature for 10 to 15 minutes, and then the heating is stopped, and an ingot of a copper alloy material is cast under the protective gas; S2, placing the alloy ingot in a holding furnace for homogenization treatment, and then performing hot rolling treatment; S3, subjecting the hot-rolled alloy ingot to a solution treatment at 850°C to 1000°C, and keeping the temperature for 1 h to 2 h to obtain an alloy plate; S4, subjecting the alloy sheet to a first cold rolling deformation; and then subjecting the alloy sheet to a first aging treatment; the aging treatment temperature is 350°C to 500°C, and the holding time is 4 h to 6 h; S5. The alloy plate after the first aging treatment is subjected to a second cold rolling deformation; and then subjected to a second aging treatment; the aging treatment temperature is 350°C to 450°C, and the holding time is 1 h to 3 h, to obtain a high-strength, high-conductivity, and high-toughness copper-chromium-zirconium alloy.

[0005] The present invention controls the Cr content of the alloy ingot to be less than 0.8 wt%, and the Zr content to be less than 0.07 wt%. The alloy content is intentionally reduced to reduce the scattering of electrons by solute atoms to improve the electrical conductivity, and the cost can be reduced. A large number of defects are introduced through the initial rolling process to provide a favorable nucleation position for fine precipitates, and in turn, more dislocations and deformation twins are formed in the final rolling process. The first aging treatment is then carried out to introduce a nano-precipitate phase, which can pin the dislocation movement during the second rolling process, and provide a uniform nucleation position for the formation of the precipitate phase during the aging process after cold rolling. The second cold rolling is then carried out to control the deformation within 20%, so that the dislocation accumulation inside the alloy can be further increased and the grain boundary change can be ensured not to be too large to reduce the influence on the electrical conductivity of the alloy. Finally, the secondary aging is carried out, and the aging temperature and time are regulated to control the size, quantity and morphology of the secondary precipitate phase to avoid the influence of recovery softening on the mechanical properties of the alloy. Therefore, reasonable regulation of the parameters of the two rolling and aging treatments (initial rolling, intermediate aging, final rolling, and final aging) is an effective strategy to optimize the precipitation phase formation process and improve the alloy properties.

[0006] As a further preferred embodiment, in order to obtain an alloy with uniform composition, the Cr content in the Cu-Cr master alloy is 3% to 15%; the Zr content in the Cu-Zr master alloy is 30% to 50%.

[0007] As a further preferred embodiment, the temperature of the homogenization treatment in S2 is 800° C. to 950° C., and the holding time is 1 h to 3 h.

[0008] As a further preferred embodiment, the hot rolling treatment in S2 is subjected to 3 to 5 deformation passes, the deformation amount of each pass is 10% to 30%, the rolling speed is 10 m / min to 12 m / min, and the width of the alloy grain after deformation is 40 μm to 60 μm. Controlling these parameters in the above preparation process can ensure uniform deformation of the organization and precise size control.

[0009] As a further preferred embodiment, the first cold rolling deformation in S4 is performed with 4-7 deformation passes; and the total deformation amount of the first cold rolling deformation is 50% to 90%.

[0010] As a further preferred embodiment, the deformation amount of each pass in the first cold rolling deformation is 10% to 30%, the rolling speed is 10 m / min to 12 m / min, and the width of the alloy grains after deformation is 5 μm to 8 μm.

[0011] As a further preferred embodiment, the second cold rolling deformation in S5 is performed for 3-5 times; and the total deformation amount of the second cold rolling deformation is 10% to 50%.

[0012] As a further preferred embodiment, the deformation amount of each pass in the second cold rolling deformation is 4% to 7%, the rolling speed is 6 m / min to 8 m / min, and the width of the alloy grains after deformation is 1 μm to 3 μm.

[0013] In a second aspect, the present invention provides a high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy, wherein the high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy is prepared by the preparation method described in any one of claims 1-8.

[0014] As a further preferred embodiment, the high-strength, high-conductivity, high-toughness copper-chromium-zirconium alloy comprises the following components by weight percentage: Cr: 0.5wt% to 0.8wt%, Zr: 0.02wt% to 0.07wt%, and the balance is Cu. More preferably, the high-strength, high-conductivity, high-toughness copper-chromium-zirconium alloy comprises the following components by weight percentage: Cr: 0.67wt%, Zr: 0.065wt%, and the balance is Cu.

[0015] The beneficial effects of the present invention are: (1) The present invention controls the Cr content to 0.5-0.8wt% and the Zr content to 0.05-0.07wt%, and reduces the content of solute atoms to reduce their scattering of electrons to obtain high conductivity, and can also prevent excessive Cr atoms from embrittlement of the alloy grain boundaries and affecting the toughness of the alloy. Through the interaction of Cr and Zr elements and combined with multi-stage cold working and multi-stage aging treatment, the second cold rolling controls the deformation within 20%, which can not only further increase the dislocation accumulation inside the alloy but also ensure that the grain boundary changes will not be too large to reduce the impact on the electrical conductivity of the alloy. The secondary aging temperature and time are regulated to control the size, quantity and morphology of the secondary precipitated phase to avoid the impact of recovery softening on the mechanical properties of the alloy, and further improve the comprehensive performance of the copper alloy.

[0016] (1) The present invention provides a method for preparing an alloy, which includes processes such as melting and casting, hot rolling, aging and cold deformation. The process is simple and effective, with a short flow, and is suitable for large-scale production of high-strength and high-conductivity copper alloy strips for lead frames. The method has low cost, excellent mechanical and electrical properties, and can meet the performance requirements of high-end integrated circuit lead frame copper alloys. In particular, the method has good application prospects in the fields of electronic communications and rail transportation.

[0017] (2) According to the preparation method of the present invention, the present invention also provides an alloy with excellent performance, which ensures high strength while also ensuring excellent electrical conductivity and high toughness. The prepared Cu-Cr-Zr alloy strip has a tensile strength of about 560 MPa, and in particular an electrical conductivity of about 91% IACS, a microhardness of more than 170 HV, and an elongation after fracture of about 12%, showing significantly improved comprehensive performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 The figure shows the preparation flow chart of the Cu-Ni-Si alloy of the present invention; Figure 2 Shown is a scanning electron microscope image of the copper alloy material prepared in Example 2; Figure 3 The SEM image of the copper alloy material prepared in Example 3 is shown. Figure 4 Shown is a scanning electron microscope image of the copper alloy material prepared in Comparative Example 1; Figure 5Shown is a scanning electron microscope image of the copper alloy material prepared in Comparative Example 3. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] The main test methods and standards related to the present invention: the alloy composition of the copper alloy material is evaluated according to the national standard "GB / T5121-2008 Chemical Analysis Method for Copper and Copper Alloys" and other standards; the hardness is evaluated according to GB / T4340.1-2009 "Vickers Hardness Test for Metallic Materials Part 1: Test Method" and other standards; the tensile strength and elongation are evaluated according to the national standards "GB / T228.1-202 Tensile Test for Metallic Materials Part 1: Room Temperature Test Method", "GB / T20254.1-2015 Copper and Copper Alloy Strips for Lead Frames Part 1 Flat Strip" and other standards; the conductivity is evaluated according to the national standard "GB / T351-2019 Resistivity Measurement Method for Metallic Materials" and other standards.

[0022] The raw materials used in the following examples are high-quality electrolytic copper with a purity of 99.99%, a Cu-Cr master alloy with a Cr content of 5-15wt%, and a Cu-Zr master alloy with a Zr content of 30-50wt%.

[0023] Example 1 A method for preparing a high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy specifically comprises the following steps: The mass percentages of the prepared copper-chromium-zirconium alloy are: Cr 0.67wt%, Zr 0.065wt%, and the rest is copper; in this embodiment, the Cu element is added in the form of 99.99% pure copper; the Cr element is added in the form of a Cu-Cr master alloy, and the mass fraction of the Cr element is 10%; the Zr element is added in the form of a Cu-Zr master alloy, and the mass fraction of the Zr element is 40%.

[0024] (1) Alloy melting and casting: Raw materials are prepared according to the alloy composition and mass percentage, and the raw materials are placed in the graphite crucible of the induction furnace. The melting is carried out in a vacuum medium frequency melting furnace with a maximum capacity of 10 kg. Before melting, the raw materials, crucible and mold are preheated, and then the raw materials are placed in the crucible. After closing the furnace door, the vacuum furnace body is evacuated to 1×10 -2Pa, turn on the medium frequency heating, preheat with 5kw power for 5 minutes, increase the power to 15-20kw until the material is completely melted; turn off the vacuum system, and then introduce pure argon (Ar volume fraction ≥99.99%), smelting under the protection of pure argon, wait until the solid is completely melted to form alloy melt, then heat the alloy melt to 1250℃, let it stand for 10 minutes, and then cast it into a graphite mold, open the mold and take out the alloy ingot after cooling; (2) Homogenization treatment: The obtained ingot is placed in a heat treatment furnace for homogenization treatment at a temperature of 900°C for a holding time of 2 hours; (3) Hot rolling: The homogenized alloy material is directly taken out and quickly hot-rolled into a strip. The total deformation of hot rolling is 80%. The hot-rolled alloy strip is naturally cooled to room temperature. (4) Solution treatment: The hot-rolled alloy strip is placed in a heat treatment furnace for solution treatment at a temperature of 950°C for 2 hours. The alloy strip is then immediately water quenched and rapidly cooled to room temperature. (5) First cold rolling deformation: After the solution treatment, the surface oxide scale of the alloy strip is removed and the first cold rolling is performed. The cold rolling deformation is performed for 7 times, and the deformation of each time is about 20%. The rolling speed is 10 m / min, the total rolling deformation is 80%, and the width of the alloy grain after deformation is about 50 μm. (6) First aging treatment: The alloy strip after the first cold rolling deformation is placed in a heat treatment furnace for the first aging treatment. The aging temperature is 400°C and the holding time is 6 hours. After aging, it is air-cooled to room temperature. (7) Second cold rolling deformation: The alloy strip after the primary aging treatment is rolled at room temperature. The second cold rolling deformation is performed for 3 passes, with a deformation of about 5% in each pass. The rolling speed is 6 m / min to 8 m / min, the total rolling deformation is 20%, and the alloy grain width after deformation is about 1 μm. (8) Second aging treatment: The alloy strip after secondary cold rolling deformation is placed in a heat treatment furnace for secondary aging treatment at an aging temperature of 350°C for 2 hours. After aging, it is air-cooled to room temperature to obtain a high-strength, high-conductivity, and high-toughness copper-chromium-zirconium alloy.

[0025] After testing, the obtained copper alloy material has a hardness of 187.0HV, a tensile strength of 572.7MPa, an elongation after fracture of about 10.3%, and a conductivity of 86.6%IACS.

[0026] Figure 2This is a scanning electron microscope image of the copper alloy material prepared in this embodiment. From the image, we can see that its grains are fine and uniform, the grain size is about 1-3 μm, and there are fewer coarse grains. And from the image, we can see precipitates of different sizes, and the precipitates are numerous, small in size, and dispersed in the copper alloy matrix.

[0027] Example 2 A method for preparing a high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy specifically comprises the following steps: The specific preparation process is similar to that of Example 1, the only difference being that the first aging treatment temperature of 400° C. is changed to 450° C., and the insulation time of 6 hours is changed to 4 hours. The other processes are the same.

[0028] After testing, the obtained copper alloy material has a hardness of 173.9HV, a tensile strength of 559.4MPa, an elongation after fracture of about 11.3%, and a conductivity of 87.6%IACS.

[0029] Example 3 A method for preparing a high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy, wherein the specific process is similar to that of Example 1, except that the first aging treatment temperature of 400° C. is changed to 450° C., and the other processes are the same.

[0030] After testing, the obtained copper alloy material has a hardness of 167.0HV, a tensile strength of 558.7MPa, an elongation after fracture of approximately 10.4%, and a conductivity of 90%IACS.

[0031] Example 4 A method for preparing a high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy specifically comprises the following steps: The specific preparation process is similar to that of Example 1, except that the first aging temperature of 400°C is changed to 450°C, the insulation time of 6 hours is changed to 4 hours, and the second aging treatment temperature of 350°C is changed to 400°C. The other processes are the same.

[0032] After testing, the obtained copper alloy material has a hardness of 171.9HV, a tensile strength of 558.4MPa, an elongation after fracture of about 13.5%, and a conductivity of 91.5%IACS.

[0033] Example 5 A method for preparing a high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy, wherein the specific process is similar to that of Example 4, the only difference being that the first aging treatment, the holding time is changed from 4 hours to 6 hours, and the other processes are the same.

[0034] After testing, the obtained copper alloy material has a hardness of 167.1HV, a tensile strength of 554.7MPa, an elongation at break of approximately 12.1%, and a conductivity of 92.2%IACS.

[0035] Comparative Example 1 A method for preparing a high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy specifically comprises the following steps: The mass percentages of the prepared copper-chromium-zirconium alloy are: 0.67wt% Cr, 0.065wt% Zr, and the rest is Cu. The Cu element is added in the form of pure copper with a purity of 99.99%; the Cr element is added in the form of a Cu-Cr master alloy with a mass fraction of 10%; and the Zr element is added in the form of a Cu-Zr master alloy with a mass fraction of 40%.

[0036] (1) Alloy melting and casting: Raw materials are prepared according to the alloy composition and mass percentage, and the raw materials are placed in the graphite crucible of the induction furnace. The melting is carried out in a vacuum medium frequency melting furnace with a maximum capacity of 10 kg. Before melting, the raw materials, crucible and mold are preheated, and then the raw materials are placed in the crucible. After closing the furnace door, the vacuum furnace body is evacuated to 1×10 -2 Pa, turn on the medium frequency heating, preheat with 5kw power for 5 minutes, increase the power to 15-20kw until the material is completely melted; turn off the vacuum system, and then introduce pure argon (Ar volume fraction ≥99.99%), smelting under the protection of pure argon, wait until the solid is completely melted to form alloy melt, then heat the alloy melt to 1250℃, let it stand for 10 minutes, and then cast it into a graphite mold, open the mold and take out the alloy ingot after cooling; (2) Homogenization treatment: The obtained ingot is placed in a heat treatment furnace for homogenization treatment at a temperature of 900°C for a holding time of 2 hours; (3) Hot rolling: The homogenized alloy material is directly taken out and quickly hot-rolled into a strip. The total deformation of hot rolling is 80%. The hot-rolled alloy strip is naturally cooled to room temperature. (4) Solution treatment: The hot-rolled alloy strip is placed in a heat treatment furnace for solution treatment at a temperature of 950°C for 2 hours. The alloy strip is then immediately water quenched and rapidly cooled to room temperature. (5) Cold rolling deformation: After the solution treatment, the surface oxide scale of the alloy strip is removed and the first cold rolling deformation is carried out. The cold rolling deformation is carried out for 7 times in total. The deformation amount of each cold rolling deformation is about 20%. The rolling speed is 10 m / min, the total rolling deformation amount is 90%, and the width of the alloy grain after deformation is about 30 μm. (6) Aging treatment: The alloy strip after the primary cold rolling deformation is placed in a heat treatment furnace for aging treatment at a temperature of 400°C for 4 hours. After aging, it is air-cooled to room temperature to obtain the final sample. After testing, the obtained copper alloy material has a hardness of 165.5HV, a tensile strength of 530.6MPa, an elongation after fracture of about 9.5%, and a conductivity of 80.2%IACS.

[0037] Comparative Example 2 A method for preparing a high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy, wherein the specific process is similar to that of comparative example 1, the only difference being the aging treatment, the heat preservation time being 6 hours, and the others remaining the same.

[0038] After testing, the obtained copper alloy material has a hardness of 161.6HV, a tensile strength of 521.0MPa, an elongation after fracture of about 8.8%, and a conductivity of 81.2%IACS.

[0039] Comparative Example 3 A method for preparing a high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy, wherein the specific process is similar to that of comparative example 1, the only difference being the aging treatment, the holding temperature being 450°C for hours, and the others remaining the same.

[0040] After testing, the obtained copper alloy material has a hardness of 143.3HV, a tensile strength of 508MPa, an elongation after fracture of about 9.6%, and a conductivity of 80.8%IACS.

[0041] Figure 5 This is a scanning electron microscope image of the copper alloy material prepared in this comparative example. From the image, we can see that its grains are coarse and uneven in size, and the grain size is about 30μm. And we can see from the image that the number of precipitated phases is small and the size is large.

[0042] Comparative Example 4 Compared with comparative example 3, the difference is that the aging treatment and the heat preservation time are 6 hours. The other preparation steps are the same.

[0043] After testing, the obtained copper alloy material has a hardness of 133.6HV, a tensile strength of 484.8MPa, an elongation after fracture of about 9.1%, and a conductivity of 81.6%IACS.

[0044] Table 1 As can be seen from the above table, the present invention controls the Cr content of the alloy ingot to be less than 0.8 wt%, and the Zr content to be less than 0.07 wt%. The alloy content is intentionally reduced to reduce the scattering of electrons by solute atoms to improve the electrical conductivity, and the cost can be reduced. The introduction of a large number of defects through the initial rolling process provides a favorable nucleation position for fine precipitates, which in turn leads to the formation of more dislocations and deformation twins in the final rolling process. The first aging treatment is then carried out, and nano-precipitated phases can be introduced, which can pin dislocation movement during the second rolling process, providing a uniform nucleation position for the formation of precipitated phases during the aging process after cold rolling. The second cold rolling controls the deformation within 20%, which can further increase the dislocation accumulation inside the alloy and ensure that the grain boundary changes will not be too large to reduce the impact on the electrical conductivity of the alloy. Finally, the secondary aging is carried out, and the aging temperature and time are regulated to control the size, quantity and morphology of the secondary precipitated phase to avoid the impact of recovery softening on the mechanical properties of the alloy. Therefore, reasonable regulation of the parameters of the two rolling and aging treatments (initial rolling, intermediate aging, final rolling, and final aging) is an effective strategy to optimize the precipitation phase formation process and improve the alloy properties.

[0045] Cu-Cr-Zr alloys have been widely used in many high-demand application scenarios, especially in situations where higher conductivity is required, especially in high-current conductive connectors, power transmission wires, electronic connectors, integrated circuit packaging, resistance welding electrodes and high-frequency electrical equipment. The conductivity needs to reach more than 90% IACS, mainly because in these fields, high conductivity plays a vital role in improving efficiency, reducing energy loss, reducing equipment heat and improving equipment reliability. The Cu-Cr-Zr alloy strip prepared by the preparation method provided by the present invention fully meets this requirement.

[0046] The embodiments of the present application are described above in conjunction with the accompanying drawings. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the core idea of ​​the present application, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the inspiration of the present application, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present application and the claims, all of which are within the protection of the present application.

Claims

1. A method for preparing a high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy, characterized in that: The following steps are involved: S1. Place copper, Cu-Cr master alloy and Cu-Zr master alloy in a vacuum medium frequency induction furnace. -2 Pa or more until the material is completely melted, the vacuum is turned off, and then a protective gas is introduced to keep the temperature for 10 to 15 minutes, and then the heating is stopped, and an ingot of a copper alloy material is cast under the protective gas; S2, placing the alloy ingot in a holding furnace for homogenization treatment, and then performing hot rolling treatment; S3, subjecting the hot-rolled alloy ingot to a solution treatment at 850°C to 1000°C, and keeping the temperature for 1 h to 2 h to obtain an alloy plate; S4, subjecting the alloy sheet to a first cold rolling deformation; and then subjecting the alloy sheet to a first aging treatment; the aging treatment temperature is 350°C to 500°C, and the holding time is 4 h to 6 h; S5. The alloy plate after the first aging treatment is subjected to a second cold rolling deformation; and then subjected to a second aging treatment; the aging treatment temperature is 350°C to 450°C, and the holding time is 1 h to 3 h, to obtain a high-strength, high-conductivity, and high-toughness copper-chromium-zirconium alloy.

2. The preparation method according to claim 1, characterized in that: The content of Cr in the Cu-Cr master alloy is 3% to 15%; the content of Zr in the Cu-Zr master alloy is 30% to 50%.

3. The preparation method according to claim 1, characterized in that: The temperature of the homogenization treatment in S2 is 800°C to 950°C, and the insulation time is 1 h to 3 h.

4. The preparation method according to claim 1, characterized in that: In the S2, the hot rolling treatment is performed for 3 to 5 deformation passes, the deformation amount of each pass is 10% to 30%, the rolling speed is 10 m / min to 12 m / min, and the width of the alloy grains after cold deformation is 40 μm to 60 μm.

5. The preparation method according to claim 1, characterized in that: The first cold rolling deformation in S4 is performed with 4-7 deformation passes; the total deformation amount of the first cold rolling deformation is 50% to 90%.

6. The preparation method according to claim 5, characterized in that: The deformation amount of each pass in the first cold rolling deformation is 10% to 30%, the rolling speed is 10 to 12 m / min, and the width of the alloy grains after cold deformation is 5 μm to 8 μm.

7. The preparation method according to claim 1, characterized in that: The second cold rolling deformation in S5 is performed for 3-5 times; the total deformation amount of the second cold rolling deformation is 10%-50%.

8. The preparation method according to claim 7, characterized in that: The deformation amount of each pass in the second cold rolling deformation is 4% to 7%, the rolling speed is 6 to 8 m / min, and the width of the alloy grains after deformation is 1 to 3 μm.

9. A high-strength, high-conductivity, high-toughness copper-chromium-zirconium alloy, characterized in that: The high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy is prepared by the preparation method described in any one of claims 1-8.

10. The high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy according to claim 9, characterized in that: The high-strength, high-conductivity and high-toughness copper-chromium-zirconium alloy comprises the following components by weight percentage: Cr: 0.5wt% to 0.8wt%, Zr: 0.02wt%~0.07wt%, the balance is Cu.

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