Efficient short-process processing preparation method for high-strength and high-elasticity copper-nickel-tin alloy
Through the combination of flash annealing treatment and aging treatment, the problems of low strength and room temperature brittleness of copper-nickel-tin alloys are solved, and the high strength and elasticity of the alloys are achieved, which improves its comprehensive performance and production efficiency.
Patent Information
- Application Number
- CN202510347274.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-24
- Publication Date
- 2025-06-10
AI Technical Summary
The strength of the copper-nickel-tin alloy is relatively low, and the brittle phase is easily formed during the aging treatment, resulting in the alloy being brittle at room temperature, affecting its ductility and comprehensive performance.
The nanoprecipitates are melted back through flash annealing, resulting in residual interface defects, controlling the diffusion of solid-solved elements, and precipitating nickel and tin elements in the grains are preferred to reduce the formation of brittle phases, reduce or avoid room temperature brittleness, and ensure the improvement of alloy strength.
The formation of brittle phase is effectively reduced, the tensile strength and elastic modulus of the alloy are improved, and the elongation is maintained, so that the alloy has excellent comprehensive performance, shortens the aging time and improves production efficiency.
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Figure CN120119192A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of high-performance copper alloy preparation, and relates to a method for efficiently and short-process preparing a high-strength and high-elastic copper-nickel-tin alloy. Background Art
[0002] Copper-beryllium alloy has relatively high strength and elastic modulus, and is a mainstream high-reliability connector and lead frame material, which is widely used in fields such as aerospace, information transmission, and precision instruments. However, the stress relaxation rate of copper-beryllium alloy increases sharply in an environment above 150 °C. Moreover, the oxides and dust generated during the melting and processing of copper-beryllium alloy are highly toxic and can cause great harm to the human body, resulting in a relatively high risk in the production process of copper-beryllium alloy, and strict protection must be carried out, resulting in a sharp increase in protection costs.
[0003] Copper-nickel-tin alloy has relatively high elastic modulus, stress relaxation resistance and good electrical conductivity, and has relatively high potential to replace copper-beryllium alloy. However, the strength of copper-nickel-tin alloy is relatively low, which limits its application. Usually, the strength of copper-nickel-tin alloy can be strengthened by age hardening. However, during the aging process, solute elements are prone to diffuse to the grain boundaries to form brittle D0 3 -Ni 3 Sn phase, resulting in a decrease in the ductility of the alloy and room temperature brittleness. Although the occurrence of room temperature brittleness can be reduced by shortening the aging time, cold deformation, and introducing microalloying elements, shortening the aging time will affect the precipitation strengthening effect and thus affect the improvement of alloy strength; cold deformation provides the nucleation driving force for nano-precipitates and shortens the aging precipitation time. However, during the cold deformation process, long-range dislocations are inevitably introduced as atomic diffusion channels, resulting in the enrichment of harmful phases at the grain boundaries, and a large number of deformation dislocations introduced by cold deformation will also damage the ductility of the alloy; introducing microalloying elements will increase the difficulty of controlling the microstructure of the alloy and increase the manufacturing and recycling costs of the alloy.
[0004] Therefore, it is necessary to provide a method for efficiently and short-process preparing a high-strength and high-elastic copper-nickel-tin alloy, which can effectively improve the strength of the copper-nickel-tin alloy, and reduce or avoid the influence of strength improvement on its ductility, so that the comprehensive performance of the copper-nickel-tin alloy is improved and it has better applicability. Summary of the Invention
[0005] In order to overcome the above problems, the present invention remelts nano-precipitates by flash annealing to generate residual interface defects, so as to control the diffusion of solute elements responsible for forming precipitation strengthening phases. During the aging process, nickel and tin elements responsible for forming nano-precipitates preferentially precipitate within the grains, thereby reducing the formation amount of brittle D0 3 -Ni 3 Sn phase, reducing or avoiding the occurrence of room temperature brittleness in the alloy, and at the same time ensuring that the strength of the alloy is effectively improved, so that the alloy has excellent comprehensive performance.
[0006] To achieve the above object, the present invention is realized through the following technical solutions:
[0007] The preparation method includes the following steps:
[0008] (1) Weigh the raw materials of copper, nickel, and tin according to the mass percentages of the alloy components, and successively wash, ultrasonically clean, and dry the raw materials to obtain clean and dry raw materials;
[0009] (2) Vacuum melt and cast the clean and dry raw materials obtained in step (1) successively to obtain a Cu-Ni-Sn alloy ingot;
[0010] (3) Perform homogenization treatment on the Cu-Ni-Sn alloy ingot obtained in step (2), and then cool it in the furnace;
[0011] (4) Perform multi-pass cold rolling treatment on the cooled Cu-Ni-Sn alloy ingot in step (3) to obtain a rolled alloy;
[0012] (5) Perform flash annealing treatment on the rolled alloy obtained in step (4);
[0013] (6) Immediately perform solution-aging treatment on the alloy after flash annealing treatment in step (5), and then air-cool to obtain a copper-nickel-tin-based alloy.
[0014] Preferably, the alloy components include by mass percentage: Ni: 6% - 15%, Sn: 2% - 8%, and the balance is Cu.
[0015] Preferably, in step (2), the vacuum degree of vacuum melting is 1×10 -3 Pa - 5×10 -3 Pa, the melting temperature is 1450°C - 1550°C, and the melting time is 10 min - 15 min.
[0016] Preferably, in step (3), the homogenization treatment temperature is 900°C, and the holding time is 2 h.
[0017] Preferably, in step (4), the single-pass cold rolling deformation amount ≤ 10%, and the total cold rolling deformation amount is 60% - 80%.
[0018] Preferably, in step (5), the heating rate of flash annealing treatment is 10 - 20°C / s, the annealing temperature is 300 - 600°C, and the holding time is 10 min.
[0019] Preferably, in step (6), the solution treatment temperature is 800°C, the holding time is 2 h, and the cooling method is water quenching.
[0020] Preferably, in the step (6), the aging treatment temperature is 400 °C and the heat preservation time is 1 - 6 h.
[0021] Preferably, in the step (1), dilute hydrochloric acid is used to wash the raw materials to remove the oxide layer on the surface of the raw material metal, and alcohol is used to ultrasonically clean the raw materials.
[0022] Preferably, in the step (2), before vacuum melting, argon is used to clean the melting cavity to discharge the air in the melting cavity; in the step (4), before cold rolling, the surface defects of the Cu-Ni-Sn alloy ingot are milled off, and the surface of the Cu-Ni-Sn alloy ingot is cleaned.
[0023] Advantages of the present invention:
[0024] 1. The residual interface defects created by flash annealing in the present invention, on the one hand, control the diffusion of solute elements that form precipitation strengthening phases, effectively reducing the formation of brittle D0 3 -Ni 3 Sn phase, effectively weakening or even avoiding the influence of room temperature brittleness on the ductility of the alloy during the strength strengthening process. On the other hand, the residual interface defects also provide an element diffusion channel for solute elements during aging treatment, enabling the aging treatment to fully exert the strengthening effect on the alloy strength, and finally enabling the alloy to have excellent comprehensive properties.
[0025] 2. The copper-nickel-tin alloy prepared by the present invention produces precipitation phases L1 2 -Ni 3 Sn and D0 22 -Ni 3 Sn during the aging stage, which are mainly distributed in a dispersed form, and their size is about 10 nm, which can effectively strengthen the alloy strength.
[0026] 3. In the preparation process of the copper-nickel-tin alloy of the present invention, flash annealing is added before solution treatment, which causes a large amount of precipitation phases to remelt, leaving a large number of residual interface defects, which is beneficial to significantly shortening the alloy aging time, and enabling the alloy to maintain excellent comprehensive properties and improving production capacity.
[0027] 4. The copper-nickel-tin alloy prepared by the present invention has excellent comprehensive properties, with a tensile strength of up to 1269.7 MPa, an elastic modulus of up to 165.1 GPa, and an elongation of up to 18.6%.
[0028] 5. The preparation method of the present invention has a short process flow, high efficiency, convenient operation, low cost, and is suitable for industrial promotion and application. Description of the Drawings
[0029] Figure 1 It is a large and small angle grain boundary diagram of the copper-nickel-tin alloy prepared in Example 3 of the present invention;
[0030] Figure 2 TEM image of the copper-nickel-tin alloy prepared in Example 3 of the present invention;
[0031] Figure 3 TEM image of the copper-nickel-tin alloy prepared in Comparative Example 3 of the present invention. Detailed implementation manners
[0032] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited to the content described.
[0033] Example 1
[0034] (1) According to the mass percentages of Ni: 15%, Sn: 2%, and Cu: the balance, weigh the raw materials of copper blocks, nickel grains, and tin balls, wash them with dilute hydrochloric acid to remove the oxide layer on the metal surface; use alcohol for ultrasonic cleaning and drying to obtain clean and dry raw materials.
[0035] (2) Put the clean and dry raw materials in step (1) into a vacuum medium frequency induction furnace, wash the furnace three times with argon gas, and then carry out vacuum melting for 15 minutes under the conditions of a vacuum degree of 1×10 -3 Pa and a melting temperature of 1500 °C, and then pour the melt into a preheated high-purity graphite mold to obtain a Cu-Ni-Sn alloy ingot with dimensions of 65×30×10 mm 3 .
[0036] (3) Place the alloy ingot obtained in step (2) in a muffle furnace, carry out homogenization treatment at 900 °C for 2 hours, and then cool it with the furnace.
[0037] (4) Milling the surface defects of the alloy ingot cooled in step (3), cleaning the surface, and then carrying out multi-pass cold rolling treatment with a single-pass deformation of 6% and a total rolling deformation of 60% to obtain a rolled alloy.
[0038] (5) Carry out flash annealing treatment on the rolled alloy obtained in step (4), with a heating rate of 15 °C / s, an annealing temperature of 400 °C, and a holding time of 10 minutes, and then immediately carry out solution treatment at 800 °C for 2 hours, and then water quench and cool.
[0039] (6) Subsequently carry out aging treatment on the alloy cooled in step (5), with an aging treatment temperature of 400 °C and a treatment time of 2 hours, and finally cool it in the air to obtain a copper-nickel-tin alloy.
[0040] The copper-nickel-tin alloy prepared in this example is denoted as Cu-15Ni-2Sn, and the performance of the copper-nickel-tin alloy prepared in this example is tested. The results are shown in Table 1.
[0041] Example 2
[0042] (1) According to the mass percentages of Ni: 6%, Sn: 8%, and Cu: the balance, weigh the raw materials of copper blocks, nickel grains, and tin balls, wash them with dilute hydrochloric acid to remove the oxide layer on the metal surface; use alcohol for ultrasonic cleaning, and then dry them to obtain clean and dry raw materials.
[0043] (2) Put the clean and dry raw materials from step (1) into a vacuum medium-frequency induction furnace, wash the furnace three times with argon, and then carry out vacuum melting for 10 min under the conditions of a vacuum degree of 5×10 -3 Pa and a melting temperature of 1450 °C. Then pour the melt into a preheated high-purity graphite mold to obtain a Cu-Ni-Sn alloy ingot with dimensions of 65×30×10 mm 3 .
[0044] (3) Place the alloy ingot obtained in step (2) in a muffle furnace and carry out homogenization treatment at 900 °C for 2 h, and then cool it in the furnace.
[0045] (4) Milling the surface defects of the alloy ingot cooled in step (3), cleaning the surface, and then carrying out multi-pass cold rolling treatment with a single-pass deformation of 5% and a total rolling deformation of 70% to obtain a rolled alloy.
[0046] (5) Carry out flash annealing treatment on the rolled alloy obtained in step (4), with a heating rate of 15 °C / s, an annealing temperature of 500 °C, and a holding time of 10 min. Then immediately carry out solution treatment at 800 °C for 2 h, and then water-quench and cool.
[0047] (6) Subsequently carry out aging treatment on the alloy cooled in step (5), with an aging treatment temperature of 400 °C and a treatment time of 6 h, and finally cool it in the air to obtain a copper-nickel-tin alloy.
[0048] The copper-nickel-tin alloy prepared in this example is denoted as Cu-6Ni-8Sn. Test the properties of the copper-nickel-tin alloy prepared in this example, and the results are shown in Table 1.
[0049] Example 3
[0050] (1) According to the mass percentages of Ni: 9%, Sn: 6%, and Cu: the balance, weigh the raw materials of copper blocks, nickel grains, and tin balls, wash them with dilute hydrochloric acid to remove the oxide layer on the metal surface; use alcohol for ultrasonic cleaning, and then dry them to obtain clean and dry raw materials.
[0051] (2) Put the clean and dry raw materials from step (1) into a vacuum medium-frequency induction furnace, wash the furnace three times with argon, and then carry out vacuum melting under the conditions of a vacuum degree of 3×10 -3Pa, under the condition that the melting temperature is 1500 °C, vacuum melting is carried out for 12 min, and then the melt is cast into a preheated high-purity graphite mold to obtain a Cu-Ni-Sn alloy ingot with dimensions of 65×30×10 mm 3 ingot.
[0052] (3) Place the alloy ingot obtained in step (2) in a muffle furnace, carry out homogenization treatment at 900 °C for 2 h, and then cool it with the furnace.
[0053] (4) Milling the surface defects of the alloy ingot cooled in step (3), cleaning the surface, and then carrying out multi-pass cold rolling treatment with a single-pass deformation of 7% and a total rolling deformation of 70% to obtain a rolled alloy.
[0054] (5) Carry out flash annealing treatment on the rolled alloy obtained in step (4), with a heating rate of 20 °C / s, an annealing temperature of 400 °C, and a holding time of 10 min. Immediately after that, carry out solution treatment at 800 °C for 2 h, and then water-quench and cool.
[0055] (6) Subsequently carry out aging treatment on the alloy cooled in step (5), with an aging treatment temperature of 400 °C and a treatment time of 1 h, and finally cool it in air to obtain a copper-nickel-tin alloy.
[0056] The copper-nickel-tin alloy prepared in this example is denoted as Cu-9Ni-6Sn. The properties of the copper-nickel-tin alloy prepared in this example are tested, and the results are shown in Table 1.
[0057] Observe the grain boundaries of the copper-nickel-tin alloy prepared in this example, and the results are as Figure 1 shown.
[0058] Through Figure 1 it can be seen that there are residual interface defects at the grain boundaries of the alloy prepared by the present invention.
[0059] Observe the microstructure of the copper-nickel-tin alloy prepared in this example, and the results are as Figure 2 shown.
[0060] Through Figure 2 it can be seen that there are high-number-density L1 2 -Ni 3 Sn strengthening phases in the matrix of the alloy prepared by the present invention.
[0061] Example 4
[0062] (1) According to the mass percentages of Ni: 15%, Sn: 8%, and Cu: the balance, weigh the raw materials of copper blocks, nickel grains, and tin balls, wash them with dilute hydrochloric acid to remove the oxide layer on the metal surface; use alcohol for ultrasonic cleaning and drying to obtain clean and dry raw materials.
[0063] (2) Put the clean and dry raw materials in step (1) into a vacuum medium frequency induction furnace, wash the furnace three times with argon, and then carry out vacuum melting for 12 min under the conditions of a vacuum degree of 3×10 -3 Pa and a melting temperature of 1550 °C. Then pour the melt into a preheated high-purity graphite mold to obtain a Cu-Ni-Sn alloy ingot with dimensions of 65×30×10 mm 3 .
[0064] (3) Place the alloy ingot obtained in step (2) in a muffle furnace and carry out homogenization treatment at 900 °C for 2 h, and then cool it in the furnace.
[0065] (4) Milling the surface defects of the alloy ingot cooled in step (3), cleaning the surface, and then carrying out multi-pass cold rolling treatment with a single-pass deformation of 8% and a total rolling deformation of 80% to obtain a rolled alloy.
[0066] (5) Carry out flash annealing treatment on the rolled alloy obtained in step (4) with a heating rate of 20 °C / s, an annealing temperature of 500 °C, and an insulation time of 10 min. Then immediately carry out solution treatment at 800 °C for 2 h, and then water-quench and cool.
[0067] (6) Subsequently carry out aging treatment on the alloy cooled in step (5) at an aging treatment temperature of 400 °C for 4 h, and finally cool it in the air to obtain a copper-nickel-tin alloy.
[0068] The copper-nickel-tin alloy prepared in this example is denoted as Cu-15Ni-8Sn. Test the properties of the copper-nickel-tin alloy prepared in this example, and the results are shown in Table 1.
[0069] Example 5
[0070] (1) According to the mass percentages of Ni: 6%, Sn: 2%, and Cu: the balance, weigh the raw materials of copper blocks, nickel grains, and tin balls, wash them with dilute hydrochloric acid to remove the oxide layer on the metal surface; use alcohol for ultrasonic cleaning and drying to obtain clean and dry raw materials.
[0071] (2) Put the clean and dry raw materials in step (1) into a vacuum medium frequency induction furnace, wash the furnace three times with argon, and then carry out vacuum melting for 12 min under the conditions of a vacuum degree of 3×10 -3 Pa and a melting temperature of 1500 °C. Then pour the melt into a preheated high-purity graphite mold to obtain a Cu-Ni-Sn alloy ingot with dimensions of 65×30×10 mm 3 .
[0072] (3) Place the alloy ingot obtained in step (2) in a muffle furnace and carry out homogenization treatment at 900 °C for 2 h, and then cool it in the furnace.
[0073] (4) Mill the surface defects of the alloy ingot cooled in step (3), clean the surface, and then perform multi-pass cold rolling treatment with a single-pass deformation of 8% and a total rolling deformation of 80% to obtain a rolled alloy.
[0074] (5) Perform flash annealing on the rolled alloy obtained in step (4) at a heating rate of 10 °C / s, an annealing temperature of 600 °C, and a holding time of 10 min. Immediately after that, perform solution treatment at 800 °C for 2 h, and then water-quench and cool.
[0075] (6) Subsequently, perform aging treatment on the alloy cooled in step (5) at an aging treatment temperature of 400 °C for 2 h, and finally cool in air to obtain a copper-nickel-tin alloy.
[0076] The copper-nickel-tin alloy prepared in this example is denoted as Cu-9Ni-6Sn. Test the properties of the copper-nickel-tin alloy prepared in this example, and the results are shown in Table 1.
[0077] Comparative Example 1
[0078] The copper-nickel-tin alloy is prepared in the same method as in Example 1, with the difference that: in this comparative example, the annealing heating rate is 15 °C / min.
[0079] Test the properties of the copper-nickel-tin alloy prepared in this example, and the results are shown in Table 1.
[0080] Comparative Example 2
[0081] The copper-nickel-tin alloy is prepared in the same method as in Example 2, with the difference that: in this comparative example, the annealing heating rate is 15 °C / min.
[0082] Test the properties of the copper-nickel-tin alloy prepared in this example, and the results are shown in Table 1.
[0083] Comparative Example 3
[0084] The copper-nickel-tin alloy is prepared in the same method as in Example 3, with the difference that: in this comparative example, the annealing heating rate is 20 °C / min.
[0085] Test the properties of the copper-nickel-tin alloy prepared in this example, and the results are shown in Table 1.
[0086] Comparative Example 4
[0087] The copper-nickel-tin alloy is prepared in the same method as in Example 4, with the difference that: in this comparative example, the annealing heating rate is 20 °C / min.
[0088] Test the properties of the copper-nickel-tin alloy prepared in this example, and the results are shown in Table 1.
[0089] Comparative Example 5
[0090] The copper-nickel-tin alloy was prepared in the same manner as in Example 5, except that: the annealing heating rate in this comparative example was 10 °C / min.
[0091] The properties of the copper-nickel-tin alloy prepared in this example were tested, and the results are shown in Table 1.
[0092] Comparative Example 6
[0093] The copper-nickel-tin alloy was prepared in the same manner as in Example 3, except that: cold rolling was not performed in this comparative example, and flash annealing was directly performed after homogenization treatment.
[0094] The properties of the copper-nickel-tin alloy prepared in this example were tested, and the results are shown in Table 1.
[0095] Comparative Example 7
[0096] The copper-nickel-tin alloy was prepared in the same manner as in Example 3, except that: solution treatment was not performed in this comparative example, and aging treatment was directly performed after annealing treatment.
[0097] The properties of the copper-nickel-tin alloy prepared in this example were tested, and the results are shown in Table 1.
[0098] Comparative Example 8
[0099] The copper-nickel-tin alloy was prepared in the same manner as in Example 3, except that: aging treatment was not performed in this comparative example.
[0100] The properties of the copper-nickel-tin alloy prepared in this example were tested, and the results are shown in Table 1.
[0101] Comparative Example 9
[0102] The copper-nickel-tin alloy was prepared in the same manner as in Example 3, except that: solution-aging treatment was directly performed after cold rolling in this comparative example, and flash annealing was performed finally.
[0103] The properties of the copper-nickel-tin alloy prepared in this example were tested, and the results are shown in Table 1.
[0104] Table 1
[0105] Number Peak tensile strength (MPa) Elastic modulus (GPa) Elongation rate (%) Example 1 1012.3 162.6 14.7 Example 2 822.6 160.4 13.2 Example 3 1269.7 165.1 18.6 Example 4 1022.2 158.1 10.3 Example 5 637.6 151.1 24.3 Comparative example 1 811.2 162.3 2.8 Comparative example 2 639.5 158.2 4.4 Comparative example 3 1076.2 163.5 6.5 Comparative example 4 944.6 153.8 4.9 Comparative example 5 429.4 148.7 9.3 Comparative example 6 973.12 157.2 17.6 Comparative example 7 955.05 152.1 13.4 Comparative example 8 546.2 163.7 23.9 Comparative example 9 682.9 161.1 16.6
[0106] As can be seen from Table 1, compared with Comparative Examples 1-5, the peak tensile strength and elongation of the alloy in Examples 1-5 are significantly improved, indicating that the preparation method of the present invention can effectively strengthen the alloy strength, while reducing or even avoiding the formation of brittle phases, keeping the alloy elongation at a better level, and even showing a significant increase compared with the comparative examples. This is because through flash annealing, the nano-precipitates existing in the grains remelt into the matrix while retaining the interface defects; these residual interface defects can effectively control the diffusion direction of elements, confine them within the grains, prevent enrichment at the grain boundaries, improve the alloy strength while ensuring the elongation. In Comparative Examples 1-5, flash annealing was not carried out, and during the aging precipitation process, elements are prone to enrich at the grain boundaries and are likely to form D0 3 phase. During the deformation process, the brittle phase cannot deform well in coordination, causing stress concentration and leading to premature fracture of the alloy..
[0107] As can be seen from Table 1, the copper-nickel-tin alloy prepared in Example 3 has the best comprehensive properties, with a tensile strength of 1269.7 MPa, an elastic modulus of 165.1, and an elongation of 18.6%. Although the tensile strength of Example 5 shows a significant decrease compared with other examples, the comprehensive properties of Example 5 are still at an excellent level compared with Comparative Example 5. The reason may be that the alloy components have an impact on the alloy properties, resulting in a relatively large decrease in the tensile strength of Example 5 compared with other examples.
[0108] Through Figure 3 it can be seen that in Comparative Example 3, flash annealing was not carried out. After aging treatment, there is a certain number density of D0 3 -Ni 3 Sn brittle phases in the grain boundaries.
[0109] Compared with Comparative Examples 6-9, the comprehensive mechanical properties of Example 3 are at a relatively excellent level. Among them, in Comparative Example 6, cold rolling treatment was not carried out. The deformation energy stored during cold rolling exists in the alloy in the form of micro-stress. Without cold rolling treatment, the driving force for precipitation during aging is insufficient, resulting in a decrease in strength.
[0110] In Comparative Example 7, solution treatment was not carried out, and the dispersed solute atoms could not enter the alloy matrix. During aging, the chemical composition concentration is low, and the number of nano-precipitates generated is small, resulting in low strength.
[0111] In Comparative Example 8, aging treatment was not carried out, which necessarily leads to the failure of the solution atoms to be released from the lattice, resulting in low alloy strength. At the same time, the relatively high ductility of the alloy in Comparative Example 8 can also prove that during the process of strengthening the alloy strength through aging, it will have a greater impact on the alloy ductility.
[0112] Comparative example 9 performs flash annealing at the end, which causes the nano-precipitates released during the aging process to remelt into the matrix, thereby resulting in a decrease in the number of nano-precipitates and further leading to a decrease in strength.
Claims
1. A high-strength and high-elasticity copper-nickel-tin alloy with high efficiency and short process preparation method, characterized by: The preparation method comprises the following steps: (1) weighing copper, nickel, and tin raw materials according to the mass percentage of the alloy components, and washing, ultrasonic cleaning, and drying the raw materials in sequence to obtain clean and dry raw materials; (2) vacuum melting and casting the clean and dry raw materials obtained in step (1) to obtain a Cu-Ni-Sn alloy ingot; (3) homogenizing the Cu-Ni-Sn alloy ingot obtained in step (2), and then cooling it in the furnace; (4) performing multiple cold rolling processes on the Cu-Ni-Sn alloy ingot cooled in step (3) to obtain a rolled alloy; (5) flash annealing the rolled alloy obtained in step (4); (6) Immediately subjecting the alloy after flash annealing in step (5) to a solution-aging treatment, and then air-cooling to obtain a copper-nickel-tin alloy.
2. The preparation method according to claim 1, characterized in that: The alloy components include, by mass percentage, Ni: 6% to 15%, Sn: 2% to 8%, and the balance is Cu.
3. The preparation method according to claim 1, characterized in that: In the step (2), the vacuum melting vacuum degree is 1×10 -3 Pa~5×10 -3 Pa, the melting temperature is 1450℃~1550℃, and the melting time is 10min~15min.
4. The preparation method according to claim 1, characterized in that: In the step (3), the homogenization temperature is 900° C. and the insulation time is 2 h.
5. The preparation method according to claim 1, characterized in that: In the step (4), the deformation amount of a single cold rolling process is ≤10%, and the total deformation amount of the cold rolling process is 60% to 80%.
6. The preparation method according to claim 1, characterized in that: In the step (5), the flash annealing treatment has a heating rate of 10 to 20°C / s, an annealing temperature of 300 to 600°C, and a holding time of 10 minutes.
7. The preparation method according to claim 1, characterized in that: In the step (6), the solution treatment temperature is 800° C., the holding time is 2 h, and the cooling method is water quenching.
8. The preparation method according to claim 1, characterized in that: In the step (6), the aging treatment temperature is 400° C. and the insulation time is 1 to 6 hours.
9. The preparation method according to claim 1, characterized in that: In the step (1), the raw material is washed with dilute hydrochloric acid to remove the oxide layer on the surface of the raw metal, and the raw material is ultrasonically cleaned with alcohol.
10. The preparation method according to claim 1, characterized in that: In the step (2), argon gas is used to clean the smelting cavity before vacuum smelting to discharge the air in the smelting cavity; in the step (4), surface defects of the Cu-Ni-Sn alloy ingot are milled off and the surface of the Cu-Ni-Sn alloy ingot is cleaned before cold rolling.