A method for obtaining high-strength and high-elasticity copper alloy through heterogeneous texture

Abstract

The application discloses a method for obtaining high-strength and high-elasticity copper alloy through heterogeneous texture, and belongs to the technical field of precision elastic element preparation. The preparation process of the application comprises the following steps: a multilayer plate with different soft and hard orientations of adjacent layer textures is prepared in a mutual laminating mode, then the multilayer plate is subjected to hot rolling treatment with a large compression ratio, and finally a cyclic 'cold rolling + heat treatment' treatment process is performed. Through the method, the heterogeneous texture copper alloy prepared by the application can effectively improve the elasticity of the alloy while improving the strength of the copper alloy. The design and preparation method of the high-strength and high-elasticity copper alloy have important guiding significance for adapting to the development of future transportation, aerospace and other industries, and have very good industrial application prospect.

Description

TECHNICAL FIELD

[0001] The application relates to a method for obtaining a high-strength high-elasticity copper alloy through heterogeneous texture, and belongs to the technical field of precision elastic element preparation. BACKGROUND

[0002] High-strength elastic copper alloy generally refers to a copper alloy with a strength of 1000 MPa or above and an elastic modulus of 125 GPa or above. The high-strength high-elasticity copper alloy has a wide application prospect in the fields of electronics, electricity, aerospace, transportation, etc. The elastic copper alloy for high-reliability connectors is mainly a beryllium copper alloy. The beryllium copper alloy contains beryllium which is a highly toxic substance. The stress relaxation rate of the beryllium copper alloy increases sharply at an environment higher than 150 DEG C, and the elastic component is extremely easy to change the contact pressure in the working state, thereby causing the working failure of the connector. Developing a new type of environmentally friendly super-high-strength, high-anti-stress relaxation, excellent forming performance and high-reliability conductive elastic copper alloy has become a research hotspot of elastic materials. Cu-Ni-Mn, Cu-Ti and Cu-Ni-Sn alloys all belong to age-hardening type alloys. After deformation heat treatment, the strength and elastic properties of the alloys can be comparable to those of the beryllium copper alloy.

[0003] Patent CN114990380B discloses a 1500MPa grade beryllium-free super high strength and high toughness copper alloy and a preparation method thereof; the mass percentage of its components is: Al: 9.5-11.5%, Fe: 3.5-6.0%, Ni: 3.5-6.0%, Mn: 0.3-1.2%, Cr: 0.2-1.0%, Hf: 0.5-1.2%, Mo: 0.1-0.4%, Sn: 0.1-0.2%, the relationship between the contents of Ni, Fe and Al is (Ni+Fe): Al=0.8-1.2:1, the total content of P, S, Bi and As is controlled to be below 0.001%, and the rest is Cu and inevitable impurities. The preparation includes vacuum induction melting, homogenization treatment, blooming, high-temperature rolling, medium-temperature strong deformation continuous rolling, nano-annealing twin crystal regulation heat treatment, small deformation asynchronous cold rolling and low-temperature aging heat treatment, so that an ultra-fined microstructure, different kinds of nano-scale precipitates and high-density annealing twin crystal synergistic strengthening super high strength copper alloy plate can be obtained, and the tensile strength thereof can reach about 1500MPa, but the elongation at break is only about 4%; patent CN113403500B discloses a high-strength high-elasticity corrosion-resistant high-nickel manganese white copper alloy and a preparation method and application thereof; the weight percentage composition is: 35-45wt% of Ni, 5-15wt% of Zn, 3.01-5wt% of Mn, 0.0001-0.1wt% of P, and the balance is Cu and inevitable impurities. The invention adds elements such as Mn and P to the zinc white copper matrix. Due to the action of Ni, Mn and P, it forms a strong elastic interaction with the Cu matrix, so that a high-performance nickel-manganese white copper alloy with higher strength, better corrosion resistance and excellent elastic performance is obtained. The invention forms a Ni-Mn-P ternary compound through Ni, Mn and P, and realizes the strengthening effect of the alloy through the elastic interaction of the compound with the Cu matrix, so that the product finally realizes excellent comprehensive properties such as tensile strength, elastic modulus and corrosion resistance. The invention alloy can realize an elastic modulus of 152GPa or more, but the tensile strength is less than 950MPa.

[0004] The copper alloy material obtained by the above process has very low elongation at break and elastic modulus when the strength of the copper alloy is improved by the operation, and the elastic modulus of the material is improved, which greatly weakens the strength, and the strength and elasticity cannot be considered at the same time. Therefore, it is necessary to provide a preparation method which can improve the strength and elasticity of copper alloy, adapt to the development requirements of future high-strength high-elasticity copper alloy, and further expand the application of high-strength high-elasticity copper alloy material in various industries. SUMMARY

[0005] In view of the above-mentioned defects of the prior art, the purpose of the present application is to provide a method for obtaining high-strength and high-elasticity copper alloy through heterogeneous texture, which adopts the manner of mutual lamination to prepare a multi-layer plate with different soft and hard orientation textures of adjacent layers, then performs hot rolling treatment with a large compression ratio, and finally performs a cyclic "cold rolling + heat treatment" process to generate a microstructure with coarse and fine twin crystals laminated with each other, so as to achieve the processing goal of simultaneously considering the mechanical properties and elastic properties of the copper alloy.

[0006] The technical solution of the present application is as follows: a method for obtaining high-strength and high-elasticity copper alloy through heterogeneous texture, and the specific steps are as follows:

[0007] The copper alloy plates with soft and hard orientation textures are laminated with each other to obtain heterogeneous texture, thereby obtaining high-strength and high-elasticity copper alloy; the method comprises the following steps:

[0008] (1) Two copper alloy plates with different textures and the same thickness are obtained through a directional solidification method, one of which is hard orientation and the other is soft orientation, and the two plates are cut into the same size.

[0009] (2) The two plates with different textures are laminated together in a mutual lamination manner to form a multi-layer plate, so that the laminated multi-layer plate has different texture directions and different soft and hard orientations of adjacent layers, so as to expand the anisotropy of the material in the subsequent rolling and heat treatment process.

[0010] (3) The multi-layer plate obtained in step (2) is subjected to hot rolling with a large compression ratio.

[0011] (4) A cyclic "cold rolling + heat treatment" process is further adopted, and the total number of cycles is not less than 5, and the cold rolling deformation amount gradually decreases during the cycle. Due to the different soft and hard orientations of adjacent textures of the multi-layer plate, the microstructure of each layer changes differently during the "cold rolling + heat treatment" process after hot rolling, the hard orientation texture layer forms large coarse twins, and the soft orientation layer forms small fine twins, so that the material simultaneously has high elasticity of coarse twins and high strength of fine twins.

[0012] Preferably, the copper alloy composition and its mass percentage according to the present application are as follows: 2.0% to 4.0% of Ni, 1.5% to 3.0% of Al, 1.0% to 2.0% of Zn, 0.4% to 1.5% of Si, and the balance is copper and some unavoidable impurity elements.

[0013] Preferably, the compression amount in the large compression ratio hot rolling process in step (3) of the present application is more than 95%, the temperature of hot rolling is 800-900℃, the rolling speed is 0.5-1m / s, and the thickness reduction in each rolling pass is controlled to be 20-40%.

[0014] Preferably, the cold rolling temperature in step (4) of the present application is 20-40℃, and the cumulative deformation amount of cold rolling is 50-60%.

[0015] Preferably, the specific process parameters of heat treatment in step (4) of the present application are: temperature 400-600℃, and holding time 1-2h.

[0016] The copper alloy texture hard orientation of the present application is (111), and the soft orientation is (100), such as C7035 copper-nickel-silicon-cobalt alloy, C1820 copper-chromium alloy, C6470 copper-silicon alloy, C1890 copper-titanium alloy, C7025 copper-nickel-silicon alloy, etc.

[0017] The cyclic repetition of "cold rolling + heat treatment" process of the present application is a key step to realize heterogeneous texture, which can form different crystal orientations in microscale, so as to realize the heterogeneity of material performance in macro scale. The copper alloy component ratio ensures that the alloy has good basic performance.

[0018] Principle of the present application:

[0019] Directional solidification is a commonly used method for controlling metal solid phase transformation process, which can form a unified crystal orientation, i.e. texture, in the alloy during solidification by controlling the temperature gradient and solidification speed in the solidification process. This method is mainly applied to prepare alloy materials with specific properties, such as high-temperature alloy, hard alloy, etc.

[0020] The present application obtains two kinds of copper alloy plates with different textures by directional solidification method, one is (111) hard orientation texture, and the other is (100) soft orientation texture. Then the two kinds of plate with different textures are stacked together in the form of mutual layering to form a multi-layer plate. The purpose of this is to make the adjacent layers of the stacked multi-layer plate have different soft and hard orientations of the texture, expand the anisotropy thereof; in subsequent large compression ratio hot rolling and cyclic "cold rolling + heat treatment" process, due to the different texture changes of each layer of the multi-layer plate due to the different soft and hard orientations of the adjacent layers, the hard orientation texture layer forms large coarse twins, and the soft orientation layer forms small fine twins, so that the material has high elasticity produced by coarse twins and high strength of fine twins at the same time.

[0021] The present application has the following beneficial effects:

[0022] The method of the present application enables the material to have good elasticity while maintaining high strength, thereby greatly improving the use performance of the material. This is because the hard orientation texture layer forms large coarse twins in the process of "cold rolling + heat treatment", and the soft orientation layer forms small fine twins; the design of such structure enables the material to have good elasticity while maintaining high strength, and it can improve the performance of the material by changing the microstructure and grain orientation of the material without changing the chemical composition of the material. This undoubtedly opens up new possibilities for the research and application of copper alloy materials. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 Part of the production process diagram for obtaining high-strength and high-elasticity copper alloy plate with heterogeneous texture of the present application. DETAILED DESCRIPTION

[0024] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in combination with specific examples; however, the protection scope of the present application is not limited to the content described.

[0025] The copper alloy described in Table 1 is taken as an example to analyze and describe the embodiment of the present application, and the specific components are shown in Table 1.

[0026] Table 1 Chemical composition of the copper alloy described in the present application (wt%)

[0027]

[0028] The specific method is as follows:

[0029] (1) Two kinds of copper alloy plates with different textures are obtained by directional solidification method, one is hard orientation (111), and the other is soft orientation (100), and the two kinds of plates with different textures are cut into the same size.

[0030] (2) The two kinds of textured plates are stacked together in a mutual stacking manner to form a multi-layer plate, so that the adjacent layers of the stacked multi-layer plate have different texture directions and different soft and hard orientations, so as to expand the anisotropy of the material in the subsequent rolling and heat treatment processes.

[0031] (3) The multi-layer plate obtained in step (2) is subjected to large compression ratio hot rolling, and the compression amount is more than 95%, wherein the hot rolling temperature is 800-900°C, the rolling speed is 0.5-1 m / s, and the thickness reduction of each rolling is controlled to be 20-40%.

[0032] (4) The cyclic "cold rolling + heat treatment" process is further adopted, and the total cycle number is not less than 5, the cold rolling deformation amount gradually decreases in the cycle process, the cumulative cold rolling deformation amount is 50-60%, the cold rolling temperature is 20-40°C, the heat treatment temperature is 400-600°C, and the holding time is 1-2 h.

[0033] Example 1

[0034] The preparation method of the high-strength and high-elasticity copper alloy described in this embodiment specifically includes the following steps:

[0035] (1) The raw materials of the copper alloy having the components shown in Table 1 are prepared, and Cu, Ni, Al, Zn and Si are melted according to the contents shown in Table 1 to obtain a copper alloy base.

[0036] (2) The melted copper alloy in (1) is directionally solidified into two kinds of copper alloy plates with the same thickness and different texture directions, one of which is hard orientation (111) and the other is soft orientation (100).

[0037] (3) The two kinds of textured plates with different soft and hard orientations are stacked together in a mutual stacking manner to obtain a multi-layer copper alloy plate with heterogeneous texture, so that the soft and hard orientations of the adjacent layers of the plate are different.

[0038] (4) Then, the multi-layer copper alloy plate is subjected to large compression amount hot rolling at an opening rolling temperature of 800°C until the cumulative total deformation amount reaches 95%, and the rolling speed is 0.7 m / s, and the thickness reduction of each rolling is 30%.

[0039] (5) Then, the hot-rolled plate is subjected to cold rolling at a cold rolling temperature of 30°C, and is subjected to heat treatment after being rolled to a deformation amount of 15%, and the heat treatment temperature is 400°C, and the heat treatment holding time is 1 h; the above-mentioned "cold rolling-heat treatment" process is cycled for 5 times until the cumulative cold rolling deformation amount reaches 50%.

[0040] The yield strength and elastic constant of the high-strength and high-elasticity copper alloy finally obtained are shown in Table 2:

[0041] Table 2 Copper alloy performance test results of specific embodiment 1 of the present application

[0042]

[0043] Example 2

[0044] The preparation method of the high-strength high-elasticity copper alloy described in this embodiment specifically includes the following steps:

[0045] (1) Prepare raw materials of the copper alloy with the components shown in Table 1, melt Cu, Ni, Al, Zn and Si according to the contents shown in Table 1 to obtain a copper alloy base.

[0046] (2) The melted copper alloy in (1) is directionally solidified into two copper alloy plates with the same thickness and different texture directions by a directional solidification method, one texture direction is hard orientation (111), and the other texture direction is soft orientation (100).

[0047] (3) The two different soft and hard oriented texture plates are stacked together in a mutual layering manner, ensuring that the soft and hard orientations of the adjacent layers of the plates are different, and a multi-layer copper alloy plate with heterogeneous texture is obtained.

[0048] (4) Then, the multi-layer copper alloy plate is hot rolled at a rolling temperature of 850°C to a cumulative total deformation of 97% or more, the rolling speed is 0.5 m / s, and the thickness reduction of each rolling is 20%.

[0049] (5) Then, the hot-rolled plate is cold-rolled at a cold-rolling temperature of 20°C, and after the deformation reaches 15%, heat treatment is performed at a heat treatment temperature of 500°C and an annealing holding time of 1.5 h; the above-mentioned "cold rolling-annealing" process is repeated 7 times until the cumulative deformation of the cold rolling reaches 55%.

[0050] The yield strength and elastic constant of the high-strength high-elasticity copper alloy obtained finally are shown in Table 3:

[0051] Table 3 Copper alloy performance test results of specific embodiment 2 of the present application

[0052]

[0053] Example 3

[0054] The preparation method of the high-strength high-elasticity copper alloy described in this embodiment specifically includes the following steps:

[0055] (1) Prepare raw materials of the copper alloy with the components shown in Table 1, melt Cu, Ni, Al, Zn and Si according to the contents shown in Table 1 to obtain a copper alloy base.

[0056] (2) The copper alloy melted in (1) is directionally solidified into two copper alloy plates with the same thickness but different texture directions by a directional solidification method, one texture direction is hard orientation (111) and the other is soft orientation (100).

[0057] (3) The two plates with different soft and hard orientations are stacked together in a way that the soft and hard orientations of the adjacent layers are different, to obtain a multi-layer copper alloy plate with heterogeneous texture.

[0058] (4) Then the multi-layer copper alloy plate is hot rolled at a rolling speed of 1 m / s and a reduction of 40% per pass until the total deformation reaches 98% at a starting temperature of 900 ℃.

[0059] (5) Then the hot-rolled plate is cold-rolled at a temperature of 40 ℃, and then heat treated at a temperature of 600 ℃ for 2 h after the deformation reaches 15%. The above "cold rolling-annealing" process is repeated 10 times until the cumulative deformation of cold rolling reaches 60%.

[0060] The yield strength and elastic constant of the high-strength and high-elasticity copper alloy obtained finally are shown in Table 4:

[0061] Table 4 Performance test results of copper alloy of specific embodiment 3 of the present application

[0062]

[0063] Comparative example 1

[0064] The preparation method of the copper alloy in this comparative example is the same as that of example 2, except for step (4). Specifically, the multi-layer copper alloy plate is hot rolled until the total deformation reaches 60%.

[0065] The yield strength and elastic constant of the copper alloy obtained finally are shown in Table 5:

[0066] Table 5 Performance test results of copper alloy of specific comparative example 1 of the present application

[0067]

[0068] It can be seen from the comparison that the yield strength and elastic constant of the copper alloy plate after the large compression ratio hot rolling and the cyclic "cold rolling + heat treatment" process are significantly improved.

[0069] Hot rolling without a large amount of compression will result in a lower yield strength. The reason is that hot rolling with a large amount of compression introduces more cold deformation, resulting in more dislocations and changes in crystal structure. These changes generally help to increase the yield strength of the material. Insufficient compression deformation will result in a decrease in the yield strength of the material. In addition, hot rolling without a large amount of compression will also result in a lower elastic constant, because hot rolling with a large amount of compression helps to improve the crystal structure, reduce the grain size, and increase the elastic constant of the material. Insufficient large compression treatment may not fully optimize the crystal structure, affecting the elastic constant. Hot rolling with a large amount of compression generally helps to refine the crystal, increase the dislocation density, and thus increase the strength and hardness of the material. Insufficient compression deformation may limit the changes in the crystal structure, resulting in larger grain size and less dislocation density, affecting.

[0070] Comparative Example 2

[0071] The preparation method of the copper alloy in this comparative example is the same as that in Example 2, except that step (5) is different, specifically: this comparative example does not perform the "cold rolling + heat treatment" process.

[0072] The yield strength and elastic constant of the final copper alloy are shown in Table 6:

[0073] Table 6 Performance test results of copper alloy of specific comparative example 2 of the present application

[0074]

[0075] By comparison, it can be seen that the yield strength and elastic constant of the copper alloy sheet after the large compression ratio hot rolling and the subsequent "cold rolling + heat treatment" process are significantly improved.

[0076] Hot rolling without the "cold rolling + heat treatment" process will result in a lower yield strength and elastic constant. This is because cold rolling introduces deformation, and subsequent heat treatment helps to eliminate defects caused by deformation, optimize the crystal structure, and increase the yield strength of the material. In addition, cold rolling and heat treatment help to reduce the grain size, increase the dislocation density, improve the crystal structure, and increase the elastic constant of the material. Therefore, the "cold rolling + heat treatment" process will limit the changes in the crystal structure, affecting the mechanical properties of the material.

[0077] Comparative Example 3

[0078] The preparation method of the copper alloy in this comparative example specifically includes the following steps:

[0079] (1) Prepare the copper alloy raw materials of Example 2 as shown in Table 1, melt Cu, Ni, Al, Zn and Si according to the content shown in Table 1 to obtain a copper alloy base.

[0080] (2) The copper alloy plates with the same thickness are obtained by smelting, and the copper alloy plates are stacked together to obtain a multi-layer plate.

[0081] (3) Then the multi-layer copper alloy plates are hot-rolled at a rolling temperature of 850℃ with a large compression ratio until the total deformation reaches 97%.

[0082] (4) Then the hot-rolled plate is cold-rolled, and after the deformation reaches 15%, annealing treatment is performed at an annealing temperature of 500℃ for 1.5h; the above-mentioned "cold rolling-annealing" process is cycled 7 times until the cumulative deformation of cold rolling reaches 55%.

[0083] The yield strength and elastic constant of the copper alloy obtained finally are shown in Table 7:

[0084] Table 7 Performance test results of the copper alloy of the specific comparative example 3 of the present application

[0085]

[0086] By comparing the test results of the material performance of comparative example 3, comparative example 2 and comparative example 1, it can be found that the stacking of the heterogeneous texture plate has a very obvious strengthening effect on the yield strength and elastic constant of the copper alloy material, and the "cold rolling + heat treatment" process after large compression ratio hot rolling also has a relatively obvious improvement on the yield strength and elastic performance of the material. This is because the microstructure and performance of the heterogeneous texture copper alloy are very different from those of the single copper alloy, and there is a strong interface constraint and load transfer between the hard and soft phases in the heterogeneous texture copper alloy, and the hard phase can provide higher strength, and the soft phase can provide higher elasticity. By interlaminar texture hard orientation (111) and texture soft orientation (100), a special grain orientation distribution can be formed in the material, which maximizes the anisotropy of the material. Large compression ratio hot rolling changes the microstructure of the material through plastic deformation, so that the grain of the material is refined, thereby improving the yield strength of the material. Secondly, the cold rolling can introduce a large number of dislocations and grain boundaries, which can hinder the movement of dislocations, thereby improving the yield strength of the material. In addition, heat treatment can eliminate the stress generated during cold rolling, and through recrystallization and grain growth, the microstructure of the material can be optimized, thereby improving the elastic performance of the material.

[0087] In summary, the process method of the present application is convenient to operate, can effectively improve the twin crystal characteristics in the copper alloy substrate, obtain a copper alloy plate with heterogeneous density twin crystal layer, improve the elastic performance of the copper alloy under the premise of ensuring that the strength of the copper alloy meets the performance requirements of the alloy, and is suitable for industrial application. The present application provides a feasible technical solution for the preparation of high-strength and high-elasticity copper alloy materials for aerospace, microelectronic elastic components, rail transportation, communication and other industries.

[0088] Finally, it should be understood that the application is not limited to the details of the above-described exemplary embodiments and can be implemented in other specific forms without departing from the spirit or essential characteristics of the application.

Claims

1. A method for obtaining a high-strength high-ductility copper alloy by heterogeneous texture, characterized by, The application discloses a method for preparing a high-strength and high-elasticity copper alloy by using copper alloy plates with soft and hard orientation textures. The method comprises the following steps: (1) obtaining two copper alloy plates with different textures by a directional solidification method, wherein the thicknesses of the two plates are the same, one plate has a hard orientation texture, and the other plate has a soft orientation texture, and the two plates are cut into the same size; (2) stacking the two plates in a mutual stacking mode to form a multi-layer plate, so that the adjacent layers of the stacked multi-layer plate have different texture directions and different soft and hard orientation directions; (3) performing large compression ratio hot rolling on the multi-layer plate obtained in the step (2); (4) adopting a cyclic "cold rolling + heat treatment" treatment process, and the total cycle number is not less than 5 times, and the cold rolling deformation amount is gradually reduced in the cycle process; in the step (3), the compression amount in the large compression ratio hot rolling process is more than 95%, the hot rolling temperature is 800-900 DEG C, the rolling speed is 0.5-1 m / s, and the thickness reduction of each rolling is controlled to be 20-40%; 2. The method of claim 1, wherein the high strength and high ductility copper alloy is obtained by heterogeneous texture, and the heterogeneous texture is a texture in which a crystal orientation of a copper grain is not uniform. in the step (4), the cold rolling temperature is 20-40 DEG C, and the cumulative deformation amount of the cold rolling is 50-60%. in the step (4), the specific process parameters of the heat treatment are as follows: the temperature is 400-600 DEG C, and the holding time is 1-2 h.

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