A method for preparing and applying an endogenous fiber-reinforced copper-silver alloy sheet

Abstract

This invention relates to the field of alloy sheet processing technology, and provides a method for preparing and applying an endogenous fiber-reinforced copper-silver alloy sheet. The alloy contains 5-7 wt% Ag, less than 1 ppm oxygen, and a total Cu+Ag content of over 99.998 wt%. The preparation method includes: 1. Preparing copper-silver alloy ingots using vacuum induction melting; 2. Homogenizing the copper-silver alloy ingots using a two-stage heat treatment; 3. Forging the copper-silver alloy ingots into slabs; 4. Performing solution aging heat treatment on the copper-silver alloy; 5. Performing recovery annealing on the alloy sheet after rolling. This preparation method can effectively reduce impurity content and obtain copper-silver alloy sheets with uniform microstructure and endogenous fiber reinforcement. The copper-silver alloy sheets prepared by this invention have a thickness of 0.2-0.6 mm, a tensile strength of over 1000 MPa, and an electrical conductivity of over 80% IACS, making them suitable for use as bitters in high-intensity magnetic field systems.

Description

Technical Field

[0001] This invention relates to the field of alloy sheet technology, and in particular to a method for preparing and applying an endogenous fiber reinforced copper-silver alloy sheet. Background Technology

[0002] High-intensity magnetic field technology plays a vital role in social development, with widespread applications in fields such as magnetic resonance imaging, wind turbines, high-speed rail transportation, and new weapons. With the advancement of science and technology, the requirements for the conductivity and mechanical properties of materials in high-intensity magnetic field systems are becoming increasingly stringent. In the field of resistive magnetic fields, the conductor materials used in the biter plates of magnet systems must have a tensile strength exceeding 1 GPa and a conductivity exceeding 75% IACS to ensure that the biter plate can withstand stronger Lorentz forces and avoid excessive Joule heating. Early resistive magnet biter plates were made from materials such as Cu-Be, Cu-Cr, Cu-Nb, and Cu-Al2O3, but these materials have low conductivity, leading to excessive Joule heating in strong magnets and thus failing to meet the requirements of current strong magnet biter plates. In recent years, Cu-Ag alloys with high silver content, reinforced with eutectic fibers, have improved both their mechanical properties and conductivity, becoming the mainstream conductor material for preparing resistive strong magnet biter plates.

[0003] Currently, the main method for producing high-silver Cu-Ag alloy sheets is non-vacuum melting and casting into ingots, followed by hot forging or hot rolling to create billets, and finally cold rolling to obtain the final product. Patent CN202010350184 discloses a method for preparing Cu-Ag alloy sheets with 20-30% Ag (mass percentage), using an electromagnetic field semi-continuous casting-rolling process. Although the alloy sheet in this patent exhibits a conductivity as high as 83% IACS, its strength is only 800 MPa, which does not meet the requirements for conductor materials in magnet system biter plates. Furthermore, non-vacuum melting easily introduces impurities, negatively impacting the material's conductivity. Adding such a high Ag content for alloying increases raw material costs, and the resulting microstructure, composed of Cu-based solid solutions and (Cu+Ag) eutectic, is prone to inhomogeneity.

[0004] Therefore, developing a high-purity, uniformly structured copper-silver alloy material to prepare high-strength, high-conductivity copper-silver alloy plates, and then applying them to the manufacture of strong magnet biter plates, has become an important support for the development of strong magnetic field technology. Summary of the Invention

[0005] In view of this, the present invention provides a method for preparing and applying an endogenous fiber-reinforced copper-silver alloy sheet. This invention utilizes the properties of Cu-Ag alloy solid solutions to design a Cu-Ag alloy sheet with low Ag content. Vacuum melting technology is employed to avoid the introduction of foreign impurities. The copper-silver alloy sheet is prepared using solution aging and rolling techniques. The resulting sheet exhibits high purity, uniform microstructure, high strength, and high electrical conductivity, meeting the comprehensive performance requirements of strong magnet biter plates.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] A method for preparing an endogenous fiber-reinforced copper-silver alloy plate includes the following steps:

[0008] Step 1: Vacuum induction melting of copper and silver to obtain copper-silver alloy ingots;

[0009] Step 2: The copper-silver alloy ingot is subjected to a two-stage homogenization heat treatment to obtain a homogenized ingot blank;

[0010] Step 3: Forge the homogenized ingot to obtain a plate billet;

[0011] Step 4: Perform solution treatment and aging on the sheet material;

[0012] Step 5: Roll and recover anneal the billet obtained after step 4 to obtain the endogenous fiber reinforced copper-silver alloy plate; the mass fraction of copper in the endogenous fiber reinforced copper-silver alloy plate is 93% to 95%, and the mass fraction of silver is 5% to 7%.

[0013] Preferably, the copper-silver alloy ingot has a purity > 99.998% and an oxygen content < 1 ppm.

[0014] Preferably, in the two-stage homogenization process, the temperature of the first stage homogenization process is 760±5℃, and the holding time is 5 to 7 hours; the temperature of the second stage homogenization process is 800±5℃, and the holding time is 3 to 5 hours; after the second stage homogenization heat treatment is completed, water cooling is performed.

[0015] Preferably, the forging temperature in step three is 760℃~700℃, and water cooling is performed after forging.

[0016] Preferably, the solution temperature of the solution aging treatment in step four is 750-780℃, the holding time is 1-3h, and the cooling method is water cooling.

[0017] Preferably, the aging temperature of the solution aging treatment in step four is 250–500°C, the holding time is 1–64 h, and the cooling method is water cooling.

[0018] Preferably, the rolling in step five is cold rolling, with a deformation of 10% to 18% per pass and a total deformation of 85% to 99%.

[0019] Preferably, the annealing temperature for the recovery annealing in step five is 150–250°C, and the holding time is 1–3 hours.

[0020] The present invention also provides an endogenous fiber reinforced copper-silver alloy plate prepared by the preparation method described above, wherein the endogenous fiber reinforced copper-silver alloy plate has a tensile strength of 1 GPa or higher and an electrical conductivity of 80% IACS or higher.

[0021] The present invention also provides the application of the endogenous fiber reinforced copper-silver alloy sheet described above in the manufacture of bitter boards for resistive magnet systems.

[0022] This invention provides a method for preparing an endogenous fiber-reinforced copper-silver alloy sheet, comprising the following steps: Step 1: Vacuum induction melting of copper and silver to obtain a copper-silver alloy ingot; Step 2: Performing a two-stage homogenization heat treatment on the copper-silver alloy ingot to obtain a homogenized ingot blank; Step 3: Forging the homogenized ingot blank to obtain a sheet blank; Step 4: Performing a solution aging treatment on the sheet blank; Step 5: Rolling and recovery annealing the sheet blank obtained in Step 4 to obtain the endogenous fiber-reinforced copper-silver alloy sheet; wherein the mass fraction of copper in the endogenous fiber-reinforced copper-silver alloy sheet is 93%–95%, and the mass fraction of silver is 5%–7%. This invention employs vacuum induction melting technology to prepare copper-silver alloy ingots, effectively reducing impurity content, improving alloy purity, and minimizing electron scattering by impurity atoms. Using low-silver-content alloys to prepare plates reduces production costs. Homogenization treatment homogenizes the microstructure. Aging and rolling after forging effectively control the morphology, size, and distribution of precipitates, improving the microstructure. Utilizing the metastable phase transformation characteristics of Cu-Ag alloys, an endogenous fibrous silver phase is obtained at low silver content, enhancing the overall performance of the copper-silver alloy plates. Example results show that the copper-silver alloy plates prepared by this invention have a tensile strength of up to 1015 MPa and an electrical conductivity of 83% IACS, meeting the performance requirements of high-strength, high-conductivity conductor materials for biter plates in high-intensity magnetic field systems. Attached Figure Description

[0023] Figure 1 This illustrates the relationship between the electrical conductivity and tensile strength of the copper-silver alloy sheet as the aging treatment holding time increases, as shown in Example 1.

[0024] Figure 2 The stress-strain diagram is shown for the copper-silver alloy plate obtained by aging treatment at 450℃ for 16h in Example 1.

[0025] Figure 3This is a microstructure diagram of the copper-silver alloy sheet obtained by aging treatment at 450℃ for 16 hours in Example 1. Detailed Implementation

[0026] This invention provides a method for preparing an endogenous fiber-reinforced copper-silver alloy plate, comprising the following steps:

[0027] Step 1: Vacuum induction melting of copper and silver to obtain copper-silver alloy ingots;

[0028] Step 2: The copper-silver alloy ingot is subjected to a two-stage homogenization heat treatment to obtain a homogenized ingot blank;

[0029] Step 3: Forge the homogenized ingot to obtain a plate billet;

[0030] Step 4: Perform solution treatment and aging on the sheet material;

[0031] Step 5: Roll and recover anneal the billet obtained after step 4 to obtain the endogenous fiber reinforced copper-silver alloy plate; the mass fraction of copper in the endogenous fiber reinforced copper-silver alloy plate is 93% to 95%, and the mass fraction of silver is 5% to 7%.

[0032] This invention involves vacuum induction melting of copper and silver to obtain a copper-silver alloy ingot. In this invention, the copper is preferably an electrolytic copper plate, and the purity of the copper is preferably ≥99.99%. Before vacuum induction melting, the electrolytic copper plate is preferably pretreated, preferably by soaking in a deoxidizing solution for 2 hours followed by sanding. The silver is preferably silver shavings, and the purity of the silver is preferably ≥99.99%. The copper and silver are proportioned according to the mass fractions of silver and copper in the target endogenous fiber reinforced copper-silver alloy plate.

[0033] In this invention, the vacuum degree of the vacuum induction melting is preferably 1×10⁻⁶. -2 Pa; the temperature of the vacuum induction melting is preferably 1000-1100℃, more preferably 1020-1030℃; the vacuum induction melting is preferably carried out under inert gas protection, and the inert gas is preferably argon. In this invention, the heating method of the vacuum induction melting preferably includes: heating sequentially at 60V for 10 min, heating at 200V for 10 min, heating at 360V until the metallic copper and metallic silver are completely melted and then holding at that temperature for 20 min, holding at 320V for 10 min, holding at 280V for 10 min, holding at 230V for 10 min, holding at 180V for 10 min, and then cooling.

[0034] In a specific embodiment of the present invention, pretreated electrolytic copper plates and silver scraps are preferably mixed in a certain proportion, then loaded into a vacuum induction furnace in one go. A vacuum is then created, followed by argon gas filling, and the filling valve is closed. The furnace is then heated using the method described above for vacuum induction melting. After cooling, a copper-silver alloy ingot is obtained. The vacuum induction melting technology used in this invention can effectively reduce impurities and improve alloy purity.

[0035] In this invention, the purity of the copper-silver alloy ingot is >99.998% (i.e., the total mass fraction of Cu+Ag), and the oxygen content is <1ppm; the shape of the copper-silver alloy ingot is preferably cylindrical, and the diameter is preferably 100-110mm; in a specific embodiment of this invention, the size of the copper-silver alloy ingot is preferably Ф100mm×50mm.

[0036] After obtaining the copper-silver alloy ingot, the present invention subjectes the ingot to a two-stage homogenization heat treatment to obtain a homogenized ingot blank. In the present invention, the temperature of the first-stage homogenization treatment is preferably 760±5℃, and the holding time is preferably 5-7 hours, more preferably 6 hours; the temperature of the second-stage homogenization treatment is preferably 800±5℃, and the holding time is preferably 3-5 hours, more preferably 4 hours; after the first-stage homogenization treatment is completed, the temperature is preferably directly increased to the temperature of the second-stage homogenization heat treatment; after the second-stage homogenization treatment, water cooling is preferably performed. The present invention performs a two-stage homogenization treatment on the copper-silver alloy ingot, which can homogenize the microstructure.

[0037] After obtaining a homogenized ingot, the present invention forges the homogenized ingot to obtain a plate billet. In this invention, the forging temperature is preferably 760℃~700℃, specifically, the initial forging temperature is 760℃ and the final forging temperature is 700℃; water cooling is performed after forging. The resulting plate billet is a square piece measuring 120mm×100mm×30mm.

[0038] After obtaining the sheet blank, the present invention performs a solution aging treatment on the sheet blank. In the present invention, the solution aging temperature is preferably 750-780℃, more preferably 760℃, the solution holding time is preferably 1-3h, more preferably 2h, and water cooling is preferably performed after the solution treatment; the aging temperature is preferably 200-500℃, more preferably 450℃, the aging holding time is preferably 1-64h, more preferably 16h, and water cooling is preferably performed after the aging treatment; the present invention, by performing solution aging treatment under the above conditions, can control the precipitation of the second phase, regulate the material microstructure, and improve the material properties.

[0039] After solution treatment and aging, the billet obtained in step four is rolled and restored annealed to obtain the endogenous fiber-reinforced copper-silver alloy sheet. In this invention, the rolling is preferably cold rolling; the deformation per rolling pass is preferably 10-18%, more preferably 12.25%, and the total rolling deformation is preferably 85-99%, more preferably 98%. During cold rolling, the second-phase particles are more uniformly distributed and fibrous. The annealing temperature for the restoration annealing is preferably 150-250℃, more preferably 200℃, and the holding time is preferably 1-3 hours, more preferably 2 hours.

[0040] In this invention, the mass fraction of copper in the endogenous fiber reinforced copper-silver alloy sheet is 93% to 95%, preferably 94%, and the mass fraction of silver is 5% to 7%, preferably 6%.

[0041] The present invention also provides an endogenous fiber reinforced copper-silver alloy plate prepared by the preparation method described above; the endogenous fiber reinforced copper-silver alloy plate has an endogenous fiber silver phase inside; the thickness of the endogenous fiber reinforced copper-silver alloy plate is preferably 0.2-0.6 mm, the tensile strength is preferably 1 GPa or more, more preferably 1000-1020 MPa, and even more preferably 1015 MPa, and the electrical conductivity is preferably 80% IACS or more, more preferably 80-85% IACS, and even more preferably 83% IACS.

[0042] This invention also provides the application of the endogenous fiber reinforced copper-silver alloy sheet described above in the manufacture of biter plates for resistive magnet systems; the endogenous fiber reinforced copper-silver alloy sheet provided by this invention has high strength and high conductivity, which can meet the requirements for conductor materials in biter plates of magnet systems and has broad application prospects.

[0043] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0044] Example 1

[0045] (1) Using electrolytic copper plates with a purity greater than 99.99% and silver scraps with a purity greater than 99.99% as raw materials, the raw materials are mixed in a ratio of 6% silver and the remainder copper by mass.

[0046] (2) A Ф100mm×50mm ingot was prepared using vacuum induction melting technology. The specific steps were as follows: the proportioned copper and silver were loaded into the vacuum induction furnace at one time, and the vacuum was evacuated to 1×10⁻⁶. -2The furnace is filled with two argon gas chambers. Heating begins, and the melting temperature is 1020-1030℃. After cooling, a copper-silver alloy ingot is obtained. The purity of the copper-silver alloy ingot is 99.9987%, and the oxygen content is 0.97 pm.

[0047] (3) The obtained copper-silver alloy ingot was subjected to a two-stage homogenization heat treatment, the process being: 760℃×6h+800℃×4h, followed by water cooling. A homogenized ingot blank was obtained.

[0048] (4) The homogenized billet is forged freely at a starting temperature of 760°C and a final forging temperature of 700°C. The forged billet is a square piece of 120mm×100mm×30mm and is water-cooled after forging.

[0049] (5) Solution treatment of the forged billet: 760℃×2h, water cooling.

[0050] (6) The billet after solution treatment is aged according to the following process: 450℃×16h, water cooling.

[0051] (7) Cold rolling, with a rolling deformation of 12.25% per pass and a total rolling deformation of 98%.

[0052] (8) The cold-rolled alloy sheet is subjected to recovery annealing treatment at a temperature of 200℃ for 2 hours.

[0053] Comparative Example 1

[0054] (1) Using electrolytic copper plates with a purity greater than 99.99% and silver with a purity greater than 99.99% as raw materials, the ingredients are mixed in a ratio of 6% silver by mass and the remainder is copper.

[0055] (2) A Ф100mm×50mm ingot was prepared using vacuum induction melting technology. The specific steps were as follows: the proportioned copper and silver were loaded into the vacuum induction furnace at one time, and the vacuum was evacuated to 1×10⁻⁶. -2 The furnace is filled with two argon gas chambers. Heating begins, and the melting temperature is 1020–1030°C. After cooling, a copper-silver alloy ingot is obtained.

[0056] (3) The obtained copper-silver alloy ingot was subjected to a two-stage homogenization heat treatment: 760℃×6h+800℃×4h, followed by water cooling. A homogenized ingot blank was obtained.

[0057] (4) The obtained homogenized billet is forged freely. The initial forging temperature is 760℃ and the final forging temperature is 700℃. The forged billet is a square material of 120mm×100mm×30mm and is water-cooled after forging.

[0058] (5) Solution treatment of the forged billet: 760℃×2h, water cooling.

[0059] (6) The billet after solution treatment is aged according to the following process: 450℃×1h, water cooling.

[0060] (7) Cold rolling, with a rolling deformation of 12.25% per pass and a total rolling deformation of 98%.

[0061] (8) The cold-rolled alloy sheet is subjected to recovery annealing treatment at a temperature of 200℃ for 2 hours.

[0062] Comparative Example 2

[0063] (1) Using electrolytic copper plates with a purity greater than 99.99% and silver with a purity greater than 99.99% as raw materials, the ingredients are mixed in a ratio of 6% silver by mass and the remainder is copper.

[0064] (2) A Ф100mm×50mm ingot was prepared using vacuum induction melting technology. The specific steps were as follows: the proportioned copper and silver were loaded into the vacuum induction furnace at one time, and the furnace was evacuated to a vacuum level of 1×10⁻⁶. -2 Pa, filled with two argon gas cells. Heating begins, with a melting temperature of 1020–1030°C. After cooling, a copper-silver alloy ingot is obtained.

[0065] (3) The obtained copper-silver alloy ingot was subjected to a two-stage homogenization heat treatment: 760℃×6h+800℃×4h, followed by water cooling. A homogenized ingot blank was obtained.

[0066] (4) The obtained homogenized billet is subjected to free forging. The initial forging temperature is 760℃ and the final forging temperature is 700℃. The forged billet is a square material of 120mm×100mm×30mm and is water-cooled after forging.

[0067] (5) Solution treatment of the forged billet: 760℃×2h, water cooling.

[0068] (6) The billet after solution treatment shall be aged according to the following process: 450℃×16h, and cooled with furnace.

[0069] (7) Cold rolling, with a total rolling deformation of 10%.

[0070] (8) The cold-rolled alloy sheet is subjected to recovery annealing treatment at a temperature of 200℃ for 2 hours.

[0071] Performance testing:

[0072] Other conditions were the same as in Example 1, except that the aging treatment time was changed. The electrical conductivity and tensile strength of the resulting copper-silver alloy sheet were tested to obtain the relationship between the electrical conductivity and tensile strength of the copper-silver alloy sheet and the extension of the aging treatment holding time. Figure 1 As shown, Figure 1The nine points in the middle represent data from nine representative experiments. From left to right, the incubation times for these nine points are 1, 2, 4, 6, 8, 10, 18, 32, and 64 hours, respectively. According to... Figure 1 It can be seen that the present invention can obtain a board with a tensile strength of 1015MPa and an electrical conductivity of 83% IACS that meets the performance requirements for use in bitter boards.

[0073] Figure 2 This is the stress-strain diagram of the copper-silver alloy sheet obtained by aging at 450℃ for 16 hours in Example 1. According to... Figure 2 It can be seen that the copper-silver alloy sheet obtained in Example 1 has high strength.

[0074] Figure 3 This is a microstructure diagram of the copper-silver alloy sheet obtained by aging at 450℃ for 16 hours in Example 1. According to... Figure 3 It can be seen that a silver fiber phase was formed inside the copper-silver alloy plate prepared in Example 1.

[0075] The electrical conductivity and mechanical properties of the copper-silver alloy plates obtained in Example 1 and Comparative Examples 1-2 were tested, and the results are shown in Table 1.

[0076] Table 1. Test results of electrical conductivity and mechanical properties of copper-silver alloy plates

[0077] Example 1 83 1015 Comparative Example 1 70 900 Comparative Example 2 98.38 325

[0078] As can be seen from the data in Table 1, the copper-silver alloy plate prepared in Example 1 of the present invention has excellent mechanical properties and electrical conductivity.

[0079] The above results demonstrate that the vacuum induction melting process used in this invention to prepare low-silver-content copper-silver alloys reduces production costs, produces a more uniform microstructure, effectively reduces impurities, and achieves extremely high purity. By utilizing the metastable phase transformation characteristics of Cu-Ag alloys through an aging and rolling process, an endogenous fibrous microstructure is obtained, resulting in a tensile strength of 1015 MPa and an electrical conductivity of 83% IACS. This improved overall alloy performance meets the performance requirements of high-strength, high-conductivity conductors for biter plates in high-intensity magnetic field systems.

[0080] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an endogenous fiber-reinforced copper-silver alloy sheet, characterized in that, Includes the following steps: Step 1: Vacuum induction melting of copper and silver to obtain copper-silver alloy ingots; Step 2: The copper-silver alloy ingot is subjected to a two-stage homogenization heat treatment to obtain a homogenized ingot blank; Step 3: Forge the homogenized ingot to obtain a plate billet; Step 4: Perform solution treatment and aging on the sheet material; Step 5: Roll and recover anneal the billet obtained after step 4 to obtain the endogenous fiber reinforced copper-silver alloy sheet; the mass fraction of copper in the endogenous fiber reinforced copper-silver alloy sheet is 93%~95%, and the mass fraction of silver is 5%~7%; The solution aging treatment in step four has a solution temperature of 750~780℃, a holding time of 1~3h, and a cooling method of water cooling; the aging treatment in step four has an aging temperature of 250~500℃, a holding time of 1~64h, and a cooling method of water cooling. The rolling process described in step five is cold rolling, with a deformation of 10-18% per pass and a total deformation of 85-99%. The annealing temperature for the recovery annealing described in step five is 150-250℃, and the annealing time is 1-3 hours.

2. The preparation method according to claim 1, characterized in that, The copper-silver alloy ingot mentioned in step one has a purity > 99.998% and an oxygen content < 1 ppm.

3. The preparation method according to claim 1, characterized in that, In step two, the temperature of the first homogenization heat treatment is 760±5℃ and the holding time is 5~7h; the temperature of the second homogenization heat treatment is 800±5℃ and the holding time is 3~5h. After the second homogenization heat treatment is completed, water cooling is performed.

4. The preparation method according to claim 1, characterized in that, The forging temperature in step three is 760~700℃, and water cooling is performed after forging.

5. The endogenous fiber-reinforced copper-silver alloy plate prepared by the preparation method according to any one of claims 1 to 4, characterized in that, The tensile strength of the endogenous fiber-reinforced copper-silver alloy plate is above 1 GPa, and the electrical conductivity is above 80% IACS.

6. The application of the endogenous fiber-reinforced copper-silver alloy sheet according to claim 5 in the manufacture of bitter boards for resistive magnet systems.

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