High-strength high-conductivity Cu-Cr-P alloy and preparation method thereof

Abstract

The application belongs to the field of alloy materials, and discloses a high-strength and high-conductivity Cu-Cr-P alloy, which comprises, in percentage by weight, Cr 1.5-2.0%, P 0.15-0.5%, and the balance of copper and inevitable impurities. The preparation method comprises the following steps: firstly, putting pure copper and pure chromium into an atmospheric melting furnace to heat and melt, then cooling, adding a copper-phosphorus intermediate alloy, pouring into a mold after melting, and obtaining an ingot; and then sequentially performing homogenization treatment, hot rolling deformation treatment, solid solution treatment, first cold rolling deformation treatment, first aging treatment, second cold rolling deformation treatment, second aging treatment, third cold rolling deformation treatment and third aging treatment to obtain the high-strength and high-conductivity Cu-Cr-P alloy. The conductivity of the alloy is not less than 88.0% IACS, the ultimate tensile strength is not less than 410 MPa, and the yield strength is not less than 370 MPa.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-strength and high-conductivity copper alloy, and particularly relates to a high-strength and high-conductivity Cu-Cr-P alloy and a preparation method thereof. BACKGROUND

[0002] The high-strength and high-conductivity copper alloy is widely used in the fields of high-speed rail contact lines and integrated circuit lead frames. At present, the high-strength and high-conductivity copper alloys mainly used include Cu-Cr alloy (tensile strength ≥ 350 MPa, electrical conductivity ≥ 80% IACS), Cu-Cr-Zr alloy (tensile strength ≥ 500 MPa, electrical conductivity ≥ 75% IACS), etc. With the continuous development of chip integration technology and the continuous speed-up of high-speed rail, higher requirements are put forward for the strength and electrical conductivity of copper alloys, so it is urgent to develop new high-strength and high-conductivity copper alloys.

[0003] The representative Cu-Cr alloy material can meet the performance requirements of high strength. In both high temperature and room temperature conditions, the limit solid solubility of Cr atoms in the copper matrix is quite different, and after solid solution and aging treatment, nanoscale Cr particles will be precipitated in the copper matrix, thereby producing a strengthening effect, so that the Cu-Cr alloy has both high strength and good electrical conductivity. However, the electrical conductivity of the traditional Cu-Cr alloy is limited, and the powder metallurgy method is usually used for its preparation. The composition control is accurate, but the process is complex, the cost of the die is high, and it is difficult to prepare large-size products, so it is difficult to realize industrial mass production and wide application. SUMMARY

[0004] The technical problem to be solved by the application is to overcome the deficiencies and defects mentioned in the above background technology, and to provide a high-strength and high-conductivity Cu-Cr-P alloy and a preparation method thereof.

[0005] To solve the above technical problems, the technical solution provided by the application is as follows:

[0006] A high-strength and high-conductivity Cu-Cr-P alloy, by weight percentage, includes the following components: Cr 1.5-2.0%, P 0.15-0.5%, and the balance is copper and unavoidable impurities. In the alloy, Cr element is added, and because the solid solubility of Cr in copper is low, nanoscale Cr particles can be formed during aging, thereby strengthening the alloy; the addition of P element can improve the fluidity of the alloy melt and promote the uniform distribution of the components. P element will also form submicron and nanoscale Cr3P particles with Cr element, thereby promoting the precipitation of nanoscale Cr particles.

[0007] In this application, the amount of Cr and P elements added is also very important. If the Cr content is high (>2%), the melt is more viscous due to the high melting point of Cr, making alloy preparation more difficult. If the Cr content is low (<1.5%), the number of nano-sized Cr particles precipitated during the aging treatment of the alloy is small, which cannot provide sufficient strength increment to the alloy. If the P content is high (>0.5%), the scattering effect of P on electrons increases, and the electrical conductivity of the alloy will decrease significantly. When the P content is low (<0.15%), the fluidity of the alloy melt is poor.

[0008] Preferably, the high-strength, high-conductivity Cu-Cr-P alloy has a conductivity of not less than 88.0% IACS, an ultimate tensile strength of not less than 410 MPa, and a yield strength of not less than 370 MPa.

[0009] As a general inventive concept, the present invention also provides a method for preparing the high-strength, high-conductivity Cu-Cr-P alloy as described above, comprising the following steps:

[0010] (1) First, put pure copper and pure chromium into an atmospheric melting furnace and heat them to melt. Then, cool down and add copper-phosphorus intermediate alloy. After melting evenly, pour it into a mold to obtain an ingot.

[0011] (2) The billet is subjected to homogenization treatment, hot rolling treatment, solution treatment, first cold rolling treatment, first aging treatment, second cold rolling treatment, second aging treatment, third cold rolling treatment, and third aging treatment in sequence to obtain the high-strength and high-conductivity Cu-Cr-P alloy.

[0012] In the above preparation method, preferably, in step (1), the heating and melting temperature is 1800-2000 ℃; after the temperature drops to 700-800 ℃, the copper-phosphorus intermediate alloy is added.

[0013] In the above-described preparation method, preferably, in step (2), the homogenization treatment temperature is 950-980 ℃, the time is 1-2 h, and the ingot sample is water-cooled after homogenization treatment. The purpose of homogenization treatment is to eliminate compositional segregation caused by melting and casting. When the temperature and time of homogenization treatment are higher than the range controlled by this invention, the alloy ingot is prone to melting and oxidation, and the grains are prone to growth; when the temperature and time of homogenization treatment are lower than the range controlled by this invention, the compositional segregation of the alloy is not easily eliminated.

[0014] In the above-mentioned preparation method, preferably, in step (2), the hot rolling deformation treatment temperature is 900-950 ℃, the holding time is 1-2 h, the total reduction is 80-90%, the rolling is performed in 3-4 passes, and the reduction in each pass is 20-30%. After the hot rolling deformation treatment, the sample is water-cooled. The purpose of the hot rolling deformation treatment is to achieve dynamic recrystallization of the material and refine the grains. When the temperature and time of the hot rolling deformation treatment are higher than the range required by this invention, the alloy ingot is prone to melting, the grains are prone to growth, the performance is reduced, and the heating energy consumption is high; when the temperature and time of the hot rolling deformation treatment are lower than the range required by this invention, the alloy is prone to cracking during the hot rolling deformation process and cannot play the role of refining the grains.

[0015] In the preferred embodiment of the above preparation method, in step (2), the solution treatment temperature is 950-980 ℃, the holding time is 1-2 h, and the sample is water-cooled after the solution treatment. The purpose of the solution treatment is to re-dissolve the particles that may precipitate during hot rolling deformation into the matrix. When the temperature and time of the solution treatment are higher than the range required by this invention, the alloy grains tend to grow, and the performance deteriorates. When the temperature and time of the solution treatment are lower than the range required by this invention, the particles precipitated during the hot rolling deformation of the alloy cannot be fully dissolved into the matrix, affecting the mechanical and electrical properties of the alloy in the subsequent deformation heat treatment process.

[0016] In the preferred embodiment of the above preparation method, in step (2), the total reduction of the first cold rolling deformation treatment is 30-50%, and the rolling is performed in 2-5 passes, with a reduction of 10-20% per pass. The first cold rolling deformation treatment can improve the strength of the material, mainly because cold working will cause an increase in defects such as dislocations inside the material, thereby leading to an increase in strength; on the other hand, it can increase the distortion energy inside the material, promote the precipitation of particles during aging treatment, and reduce the thickness of the material.

[0017] The total reduction in the second cold rolling deformation treatment is 30-50%, with 2-5 rolling passes and a reduction of 10-20% per pass. The second cold rolling deformation treatment is based on the first cold rolling deformation treatment and aging treatment, further increasing the amount of defects such as dislocations, promoting further precipitation of particles, and improving the strength, hardness and electrical conductivity of the alloy.

[0018] The total deformation amount of the third cold rolling deformation treatment is 30-50%, with 2-5 rolling passes and a reduction of 10-20% per pass. The third cold rolling deformation treatment provides driving force based on the second cold rolling deformation treatment and aging treatment, allowing the particles to be fully separated.

[0019] In the above-mentioned preparation method, preferably, in step (2), the temperature of the first aging treatment is 450-500 ℃, and the time is 1-4 h. The purpose of the aging treatment is to precipitate second-phase particles, improve the hardness and strength of the alloy, and increase its electrical conductivity. When the temperature and time of the first aging treatment are higher than the range required by the present invention, the work hardening effect provided by cold rolling disappears too quickly, the alloy is prone to softening, and the hardness and strength are low; when the temperature and time of the first aging treatment are lower than the range required by the present invention, the second-phase particles cannot be fully precipitated, affecting the electrical conductivity of the alloy.

[0020] The second aging treatment is performed at a temperature of 400-450 ℃ for 1-4 hours. After the second cold rolling deformation treatment, the total reduction increases, the driving force for particle precipitation increases, and precipitation becomes easier. The second aging temperature should not be too high, nor should it be the same as the first aging treatment temperature; otherwise, particles will precipitate rapidly, the alloy will soften easily, hardness will decrease, and overall performance will be poor. Therefore, the temperature of the second aging treatment should be lower than that of the first aging treatment.

[0021] The third aging treatment is performed at a temperature of 350-400 °C for 1-4 hours. After the third cold rolling deformation treatment, the driving force for particle precipitation further increases, making it easier for residual particles in the matrix to precipitate. Therefore, the temperature of the third aging treatment should be lower than that of the second aging treatment, and the temperature of the three aging treatments should gradually decrease. When the temperature of the multi-stage aging treatment does not conform to the gradient decreasing trend required by this invention, the alloy cannot obtain excellent comprehensive mechanical and electrical properties.

[0022] This invention employs a melting and casting method to prepare a high-strength, high-conductivity Cu-Cr-P alloy. During the hot working process, cold rolling deformation and aging treatment are directly applied. Cold rolling breaks up the grains, reducing their size, and simultaneously introduces a large number of dislocations. These dislocations provide numerous nucleation sites for the precipitation of solid solution elements, promoting particle precipitation. Through three-stage cold rolling deformation and aging treatment, the second-phase particles in the alloy are fully precipitated. Therefore, the alloy exhibits nanoscale precipitates and fine grains, ensuring excellent comprehensive mechanical and electrical properties.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) The copper alloy of the present invention contains two main alloying elements, Cr and P. Under the conditions of high temperature and room temperature, the limiting solid solubility of Cr atoms in the copper matrix is ​​different. After solid solution aging treatment, Cr phase will precipitate in the copper matrix. Compared with other elements, P is a low-cost alloying element with little effect on conductivity. It has high solubility in copper and can inhibit the coarsening of Cr precipitate phase by the formation of Cr3P phase, thereby hindering dislocation movement and improving the strength and conductivity of Cu-Cr-P alloy.

[0025] (2) The high-strength, high-conductivity Cu-Cr-P alloy of the present invention has a conductivity of not less than 88.0% IACS, an ultimate tensile strength of not less than 410 MPa, and a yield strength of not less than 370 MPa. It can replace the high-cost electroplated copper in electronic packaging materials.

[0026] (3) The present invention uses the melting and casting method to prepare highly conductive Cu-Cr-P alloy. The process is simple and low-cost. It can prepare large-sized products and complex-shaped parts, and has a wide range of applications. It can realize large-scale industrial production. Attached Figure Description

[0027] Figure 1 This is a SEM image of the tensile fracture surface of the high-strength, high-conductivity Cu-Cr-P alloy obtained after step (h) in Example 5 of this invention.

[0028] Figure 2 This is an EBSD image of the side section of the alloy plate obtained after step (j) of the high-strength, high-conductivity Cu-Cr-P alloy in Embodiment 5 of the present invention. Detailed Implementation

[0029] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0030] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0031] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0032] Example 1:

[0033] A high-strength, high-conductivity Cu-Cr-P alloy of the present invention comprises, by weight percentage: Cr 1.5%, P 0.15%, with the balance being copper and unavoidable impurities.

[0034] The preparation method of the high-strength, high-conductivity Cu-Cr-P alloy in this embodiment includes the following steps:

[0035] (1) The ingredients are prepared according to the mass percentages of Cr 1.5%, P 0.15% and Cu 98.35%. Pure copper and pure chromium are placed in the graphite crucible of the atmospheric melting furnace and heated to melt at a temperature of 1800 ℃. After the pure copper and pure chromium melt, the melt temperature is reduced to 700 ℃ and then copper-phosphorus intermediate alloy is added. After melting evenly, it is poured into a mold to obtain an ingot.

[0036] (2) The billet obtained after step (1) is homogenized at a temperature of 950 °C for 1 h. After homogenization, the sample is water-cooled.

[0037] (3) The billet obtained after step (2) is subjected to hot rolling deformation treatment. The temperature of hot rolling deformation treatment is 900 ℃, the holding time is 2 h, the total reduction is 80%, and the rolling is done in 4 passes with a reduction of 20% per pass. The sample is then water-cooled after hot rolling treatment.

[0038] (4) The hot-rolled sample obtained after step (3) is subjected to solution treatment at a temperature of 950 °C and a holding time of 1 h. After solution treatment, the sample is cooled by water.

[0039] (5) The solution sample obtained after step (4) is subjected to the first cold rolling deformation treatment. The total reduction of the cold rolling deformation treatment is 30%, and the rolling is carried out in 3 passes with a reduction of 10% per pass.

[0040] (6) The cold-rolled sample obtained in step (5) is subjected to a first aging treatment at a temperature of 450 °C for 1 h.

[0041] (7) The aged sample obtained after step (6) is subjected to a second cold rolling deformation treatment. The total reduction of the cold rolling deformation treatment is 40%, and the rolling is carried out in 4 passes with a reduction of 10% per pass.

[0042] (8) The cold-rolled sample obtained after step (7) is subjected to a second aging treatment at a temperature of 400 °C for 1 h.

[0043] (9) The aged sample obtained after step (8) is subjected to a third cold rolling deformation treatment. The total deformation amount of the cold rolling deformation treatment is 50%, and the rolling is carried out in 5 passes with a reduction of 10% per pass.

[0044] (10) The cold-rolled sample obtained after step (9) is subjected to a third aging treatment at a temperature of 350 °C for 1 h to obtain a high-strength, high-conductivity Cu-Cr-P alloy.

[0045] Example 2:

[0046] A high-strength, high-conductivity Cu-Cr-P alloy of the present invention comprises, by weight percentage: Cr 1.75%, P 0.15%, with the balance being copper and unavoidable impurities.

[0047] The preparation method of the high-strength, high-conductivity Cu-Cr-P alloy in this embodiment includes the following steps:

[0048] (1) The ingredients are prepared according to the mass percentages of Cr 1.75%, P 0.15% and Cu 98.1%. Pure copper and pure chromium are placed in the graphite crucible of the atmospheric melting furnace and heated to melt at a temperature of 2000 ℃. After the pure copper and pure chromium melt, the temperature of the melt is reduced to 800 ℃ and then copper-phosphorus intermediate alloy is added. After melting evenly, it is poured into a mold to obtain an ingot.

[0049] (2) The billet obtained after step (1) is homogenized at a temperature of 980 °C for 1 h. After homogenization, the sample is water-cooled.

[0050] (3) The billet obtained after step (2) is subjected to hot rolling deformation treatment. The temperature of hot rolling deformation treatment is 900 ℃, the holding time is 3 h, the total reduction is 85%, and it is rolled in 4 passes. The reduction of each pass is about 21.3%. The sample is water-cooled after hot rolling deformation treatment.

[0051] (4) The hot-rolled sample obtained after step (3) is subjected to solution treatment at a temperature of 950 ℃ and a holding time of 2 h. After solution treatment, the sample is cooled by water.

[0052] (5) The solution sample obtained after step (4) is subjected to the first cold rolling deformation treatment. The total reduction of the cold rolling deformation treatment is 50%, and the rolling is carried out in 5 passes with a reduction of 10% per pass.

[0053] (6) The cold-rolled sample obtained in step (5) is subjected to a first aging treatment at a temperature of 500 °C for 1 h.

[0054] (7) The aged sample obtained after step (6) is subjected to a second cold rolling deformation treatment. The total reduction of the cold rolling deformation treatment is 40%, and the rolling is carried out in 4 passes with a reduction of 10% per pass.

[0055] (8) The cold-rolled sample obtained after step (7) is subjected to a second aging treatment at a temperature of 450 °C for 1 h.

[0056] (9) The aged sample obtained after step (8) is subjected to a third cold rolling deformation treatment. The total deformation amount of the cold rolling deformation treatment is 50%, and the rolling is carried out in 5 passes with a reduction of 10% per pass.

[0057] (10) The cold-rolled sample obtained after step (9) is subjected to a third aging treatment at a temperature of 400 °C for 1 h to obtain a high-strength, high-conductivity Cu-Cr-P alloy.

[0058] Example 3:

[0059] A high-strength, high-conductivity Cu-Cr-P alloy of the present invention comprises, by weight percentage: Cr 1.5%, P 0.5%, with the balance being copper and unavoidable impurities.

[0060] The preparation method of the high-strength, high-conductivity Cu-Cr-P alloy in this embodiment includes the following steps:

[0061] (1) The ingredients are prepared according to the mass percentages of Cr 1.5%, P 0.5% and Cu 98.0%. Pure copper and pure chromium are placed in the graphite crucible of the atmospheric melting furnace and heated to melt at a temperature of 2000 ℃. After the pure copper and pure chromium melt, the temperature of the melt is reduced to 750 ℃ ​​and then copper-phosphorus intermediate alloy is added. After melting evenly, it is poured into a mold to obtain an ingot.

[0062] (2) The billet obtained after step (1) is homogenized at a temperature of 950 °C for 2 h. After homogenization, the sample is water-cooled.

[0063] (3) The billet obtained after step (2) is hot rolled at a temperature of 950 ℃, a holding time of 2 h, a total reduction of 80%, and rolled in 4 passes with a reduction of 20% per pass. The sample is then water-cooled after hot rolling.

[0064] (4) The hot-rolled sample obtained after step (3) is subjected to solution treatment at a temperature of 970 ℃ and a holding time of 1 h. After solution treatment, the sample is cooled by water.

[0065] (5) The solution sample obtained after step (4) is subjected to a first cold rolling process. The total reduction of the cold rolling process is 30%, and the rolling is performed in 3 passes with a reduction of 10% per pass.

[0066] (6) The cold-rolled sample obtained in step (5) is subjected to a first aging treatment at a temperature of 475 °C for 4 h.

[0067] (7) The aged sample obtained after step (6) is subjected to a second cold rolling deformation treatment. The total reduction of the cold rolling deformation treatment is 30%, and the rolling is carried out in 3 passes with a reduction of 10% per pass.

[0068] (8) The cold-rolled sample obtained after step (7) is subjected to a second aging treatment at a temperature of 425 °C for 4 h.

[0069] (9) The aged sample obtained after step (8) is subjected to a third cold rolling deformation treatment. The total deformation amount of the cold rolling deformation treatment is 40%, and it is rolled in 2 passes with a reduction of 20% per pass.

[0070] (10) The cold-rolled sample obtained after step (9) is subjected to a third aging treatment at a temperature of 375 °C for 4 h to obtain a high-strength, high-conductivity Cu-Cr-P alloy.

[0071] Example 4:

[0072] A high-strength, high-conductivity Cu-Cr-P alloy of the present invention comprises, by weight percentage: Cr 2.0%, P 0.5%, with the balance being copper and unavoidable impurities.

[0073] The preparation method of the high-strength, high-conductivity Cu-Cr-P alloy in this embodiment includes the following steps:

[0074] (1) The ingredients are prepared according to the mass percentages of Cr 2.0%, P 0.5% and Cu 97.5%. Pure copper and pure chromium are placed in the graphite crucible of the atmospheric melting furnace and heated to melt at a temperature of 1900 ℃. After the pure copper and pure chromium melt, the melt temperature is reduced to 800 ℃ and then copper-phosphorus intermediate alloy is added. After melting evenly, it is poured into a mold to obtain an ingot.

[0075] (2) The billet obtained after step (1) is homogenized at a temperature of 970 °C for 2 h. After homogenization, the sample is water-cooled.

[0076] (3) The billet obtained after step (2) is hot rolled at a temperature of 925 ℃, a holding time of 3 h, a total reduction of 90%, and rolled in 3 passes with a reduction of 30% per pass. The sample is then water-cooled after hot rolling.

[0077] (4) The hot-rolled sample obtained after step (3) is subjected to solution treatment at a temperature of 950 ℃ and a holding time of 2 h. After solution treatment, the sample is cooled by water.

[0078] (5) The solution sample obtained after step (4) is subjected to the first cold rolling deformation treatment. The total reduction of the cold rolling deformation treatment is 50%, and the rolling is carried out in 5 passes with a reduction of 10% per pass.

[0079] (6) The cold-rolled sample obtained in step (5) is subjected to a first aging treatment at a temperature of 475 °C for 2 h.

[0080] (7) The aged sample obtained after step (6) is subjected to a second cold rolling deformation treatment. The total reduction of the cold rolling deformation treatment is 40%, and the rolling is carried out in 2 passes with a reduction of 20% per pass.

[0081] (8) The cold-rolled sample obtained after step (7) is subjected to a second aging treatment at a temperature of 425 °C for 2 h.

[0082] (9) The aged sample obtained after step (8) is subjected to a third cold rolling deformation treatment. The total deformation of the cold rolling treatment is 30%, and the rolling is carried out in 3 passes with a reduction of 10% per pass.

[0083] (10) The cold-rolled sample obtained after step (9) is subjected to a third aging treatment at a temperature of 350 °C for 2 h to obtain a high-strength, high-conductivity Cu-Cr-P alloy.

[0084] Example 5:

[0085] A high-strength, high-conductivity Cu-Cr-P alloy of the present invention comprises, by weight percentage: Cr 2.0%, P 0.25%, with the balance being copper and unavoidable impurities.

[0086] The preparation method of the high-strength, high-conductivity Cu-Cr-P alloy in this embodiment includes the following steps:

[0087] (1) The ingredients are prepared according to the mass percentages of Cr 2.0%, P 0.25% and Cu 97.75%. Pure copper and pure chromium are placed in the graphite crucible of the atmospheric melting furnace and heated to melt at a temperature of 2000 ℃. After the pure copper and pure chromium melt, the temperature of the melt is reduced to 700 ℃ and then copper-phosphorus intermediate alloy is added. After melting evenly, it is poured into a mold to obtain an ingot.

[0088] (2) The billet obtained after step (1) is homogenized at a temperature of 980 ℃ for 2 h. After homogenization, the sample is water-cooled.

[0089] (3) The billet obtained after step (2) is hot rolled. The temperature of the hot rolling deformation treatment is 900 ℃, the holding time is 1 h, the total reduction is 90%, the rolling is done in 3 passes, and the reduction of each pass is 30%. The sample is then water-cooled after hot rolling.

[0090] (4) The hot-rolled sample obtained after step (3) is subjected to solution treatment at a temperature of 980 ℃ and a holding time of 2 h. After solution treatment, the sample is cooled by water.

[0091] (5) The solution sample obtained after step (4) is subjected to the first cold rolling deformation treatment. The total reduction of the cold rolling deformation treatment is 50%, and the rolling is carried out in 5 passes with a reduction of 10% per pass.

[0092] (6) The cold-rolled sample obtained in step (5) is subjected to a first aging treatment at a temperature of 500 °C for 0.25 h.

[0093] (7) The aged sample obtained after step (6) is subjected to a second cold rolling deformation treatment. The total reduction of the cold rolling deformation treatment is 50%, and the rolling is carried out in 5 passes with a reduction of 10% per pass.

[0094] (8) The cold-rolled sample obtained after step (7) is subjected to a second aging treatment. The temperature of the second aging treatment is 400 ℃ and the time is 2 h. The SEM images of the tensile fracture surface of the aged sample along the rolling surface are shown below. Figure 1 As shown.

[0095] (9) The aged sample obtained after step (8) is subjected to a third cold rolling deformation treatment. The total deformation amount of the cold rolling deformation treatment is 50%, and the rolling is carried out in 5 passes with a reduction of 10% per pass.

[0096] (10) The cold-rolled sample obtained after step (9) is subjected to a third aging treatment at a temperature of 350 °C for 2 h to obtain a high-strength, high-conductivity Cu-Cr-P alloy. The EBSD image of its side section is shown below. Figure 2 As shown.

[0097] Comparative Example 1:

[0098] The Cu-Cr-P alloy of this comparative example comprises, by weight percentage: Cr 5.0%, P 1.0%, with the balance being copper and unavoidable impurities.

[0099] The only difference between this comparative Cu-Cr-P alloy and Example 1 is the alloy composition; the preparation method is exactly the same as that of Example 1.

[0100] Comparative Example 2:

[0101] The Cu-Cr-P alloy in this comparative example has the same alloy composition as that in Example 2. The difference is that the hot rolling deformation treatment temperature in step (3) of the preparation method of this comparative example is 700 °C, the total reduction is 50%, and other process parameters are the same as those in Example 2.

[0102] Comparative Example 3:

[0103] The Cu-Cr-P alloy in this comparative example has the same alloy composition as that in Example 3. The difference between the preparation method of the Cu-Cr-P alloy in this comparative example and that in Example 3 is that the solid solution sample obtained after step (4) is subjected to only one cold rolling treatment and one aging treatment to obtain the Cu-Cr-P alloy. The total cold rolling reduction is 70.6%, the rolling is done in 5 passes, the reduction in each pass is 14.12%, the aging temperature is 450 ℃, and the time is 3 h.

[0104] Comparative Example 4:

[0105] The Cu-Cr-P alloy in this comparative example has the same alloy composition as that in Example 4. The difference between the preparation method of the Cu-Cr-P alloy in this comparative example and that in Example 4 is that in step (8), the temperature of the second aging treatment is 500 °C and the time is 2 h. Other process parameters are the same as those in Example 4.

[0106] Comparative Example 5:

[0107] The Cu-Cr-P alloy in this comparative example has the same alloy composition as that in Example 5. The difference between the preparation method of the Cu-Cr-P alloy in this comparative example and that in Example 5 is that in step (9), the total cold rolling deformation of the third cold rolling treatment is 90%, the rolling is done in 3 passes, and the reduction of each pass is 30%. Other process parameters are the same as those in Example 5.

[0108] The high-strength, high-conductivity Cu-Cr-P alloys prepared according to the above embodiments and comparative examples were subjected to tensile and electrical conductivity tests. The ultimate tensile strength (GB / T 228.1-2021), yield strength (GB / T 228.1-2021), conductivity (GB / T 32791-2016), etc., are shown in Table 1.

[0109] Table 1. Properties of Cu-Cr-P alloys prepared in each example and comparative example.

[0110]

[0111] As shown in Table 1, the experimental results of Comparative Example 1 and Example 1 indicate that excessively high Cr and P contents lead to a decrease in the mechanical and electrical properties of the alloy, due to an increase in the number of solid solution atoms remaining in the matrix. The experimental results of Comparative Example 2 and Example 2 indicate that excessively low hot rolling temperature and total reduction result in excessively large grain size and decreased performance. The comparative results of Comparative Example 3 and Example 3 show that, with essentially the same total cold rolling reduction, multiple cold rolling aging processes, compared to single-pass cold rolling aging, allow for the full precipitation of particles in the alloy, thereby strengthening the alloy and improving electrical conductivity. The comparative results of Comparative Example 4 and Example 4 indicate that excessively high aging temperatures lead to excessively rapid precipitation of second-phase particles, with a weaker strengthening effect than high-temperature softening, resulting in a decrease in the alloy's strength and electrical conductivity. The comparative results of Comparative Example 5 and Example 5 show that excessively high cold rolling reduction leads to excessively rapid particle precipitation, with a significantly weaker strengthening effect than softening effect during subsequent aging processes, resulting in a decrease in the alloy's strength.

[0112] In summary, the Cu-Cr-P alloy prepared using the process and parameters of this invention exhibits excellent comprehensive properties, with an ultimate tensile strength of not less than 410 MPa, a yield strength of not less than 370 MPa, and an electrical conductivity of 88.0% IACS.

Claims

1. A method for preparing a high-strength, high-conductivity Cu-Cr-P alloy, characterized in that, The high-strength, high-conductivity Cu-Cr-P alloy, by weight percentage, comprises the following components: Cr 1.5-2.0%, P 0.15-0.5%, with the balance being copper and unavoidable impurities. The high-strength, high-conductivity Cu-Cr-P alloy has a conductivity of not less than 88.0% IACS, an ultimate tensile strength of not less than 410 MPa, and a yield strength of not less than 370 MPa. Its preparation method includes the following steps: (1) First, put pure copper and pure chromium into an atmospheric melting furnace and heat them to melt. Then cool down, add copper-phosphorus intermediate alloy, melt evenly, and pour into a mold to obtain a billet. (2) The billet is subjected to homogenization treatment, hot rolling deformation treatment, solution treatment, first cold rolling deformation treatment, first aging treatment, second cold rolling deformation treatment, second aging treatment, third cold rolling deformation treatment, and third aging treatment in sequence to obtain the high-strength and high-conductivity Cu-Cr-P alloy; wherein, the temperature of the hot rolling deformation treatment is 900-950℃, the holding time is 2-3 h, the total reduction is 80-90%, the rolling is performed in 3-4 passes, and the reduction in each pass is 20-30%, and the sample is water-cooled after the hot rolling deformation treatment; the total reduction in the first cold rolling deformation treatment is 30-50%, and the reduction in each pass is 10-20%; the total reduction in the second cold rolling deformation treatment is 30-50%, and the reduction in each pass is 10-20%; the total deformation in the third cold rolling deformation treatment is 30-50%, and the reduction in each pass is 10-20%; the temperature of the first aging treatment is 450-500℃. The first aging treatment is carried out at ℃ for 1-4 hours; the second aging treatment is carried out at 400-450 ℃ for 1-4 hours; the third aging treatment is carried out at 350-400 ℃ for 1-4 hours.

2. The preparation method according to claim 1, characterized in that, In step (1), the heating and melting temperature is 1800-2000 ℃; copper-phosphorus intermediate alloy is added after the temperature drops to 700-800 ℃.

3. The preparation method according to claim 1, characterized in that, In step (2), the homogenization treatment is carried out at a temperature of 950-980 ℃ for 1-2 h, and the billet sample is water-cooled after homogenization treatment.

4. The preparation method according to claim 1, characterized in that, In step (2), the solution treatment temperature is 950-980 ℃, the holding time is 1-2 h, and the sample is water-cooled after the solution treatment.

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