Copper-nickel-tin alloy with high strength and toughness and low tin content as well as preparation method and application of copper-nickel-tin alloy

Abstract

The invention discloses a copper-nickel-tin alloy with high strength and toughness and low tin content as well as a preparation method and application of the copper-nickel-tin alloy. The copper-nickel-tin alloy with high strength and toughness and low tin content comprises the following components in percentage by weight: 5.0 to 20.0 percent of Ni, 1.0 to 6.0 percent of Sn, 0 to 2.0 percent of Mn and the balance of Cu. The preparation method of the copper-nickel-tin alloy with high strength, toughness and low tin content is simple and convenient, and comprises the steps of room-temperature smelting, homogenizing annealing, hot extrusion deformation, solid solution heat treatment and aging heat treatment. According to the copper-nickel-tin alloy with the high strength and toughness and the low tin content, the tensile strength reaches 690-800 MPa, the yield strength reaches 590-680 MPa, the elongation reaches 10%-15%, in addition, the copper-nickel-tin alloy further has the advantages that component distribution is uniform, the grain size of an as-cast microstructure is small and is only 89 + / -9 microns, distribution is uniform, the arrangement direction is more consistent, and the excellent strength and toughness are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal material preparation and processing, and specifically relates to a high-strength and toughness, low-tin content copper-nickel-tin (Cu-Ni-Sn) alloy and a preparation method and application thereof. Background Art

[0002] Beryllium copper alloys are widely used in the electronics, communications, aerospace, petrochemical, and machinery manufacturing industries due to their excellent strength, formability, electrical conductivity, and elasticity, such as in integrated circuit boards, large molds, aircraft bearings, and engine contactors. Due to these excellent properties, beryllium copper alloys are known as the "king of non-ferrous elastic materials." However, because the beryllium (Be) element used in the preparation of beryllium copper alloys is harmful to the human body and the environment, it is extremely necessary to find a high-performance copper alloy with comparable performance to beryllium copper alloys and a non-toxic alternative to beryllium copper alloys. Since its introduction, Cu-Ni-Sn (copper-nickel-tin) alloys have been considered the most promising alloy to replace beryllium copper. They have comparable strength, elasticity, and electrical conductivity to beryllium copper alloys, and their resistance to thermal stress relaxation and corrosion is superior to that of beryllium copper alloys. The commonly used processing technology of Cu-Ni-Sn alloys is: casting + homogenization treatment + cold deformation treatment + solution aging. The alloys prepared using this process have problems such as coarse grain structure and uneven distribution of components and precipitated phases. Although high-strength alloys can be obtained, their plasticity is poor. For example, after processing Cu-15Ni-8Sn alloy and Cu-9Ni-6Sn alloy, their tensile strength can reach 1000-1200MPa, but the elongation is only 1-3%. To expand the application of Cu-Ni-Sn alloys, it is necessary to improve the plasticity of the alloy while maintaining high strength.

[0003] Cu-Ni-Sn alloys are highly susceptible to segregation. When the Sn content is high, a single solution treatment is difficult to completely eliminate Sn segregation. A Cu-9Ni-6Sn alloy prepared by melt casting requires a 24-hour homogenization treatment at 830°C. Subsequently, a hot forging, hot rolling, multiple solution treatments, and cold rolling process completely eliminate Sn segregation. This indicates that for alloys with high Sn contents, complex processes are required to completely eliminate segregation. Some studies have further improved the mechanical properties of Cu-Ni-Sn alloys by optimizing processing techniques. For example, a cast Cu-15Ni-8Sn alloy was subjected to homogenization annealing, hot extrusion, and multi-stage aging, resulting in an alloy with a tensile strength of 1000 MPa and an elongation of 8%. Other studies have also investigated the addition of trace elements to Cu-Ni-Sn alloys to improve the casting process and prepare high-performance alloys. Microalloying can significantly improve the strength and ductility of the alloy, but the improvement is small, and trace elements are easily burned and oxidized, placing high demands on the casting process. The new compositions and processes proposed so far have made the processing of Cu-Ni-Sn alloys more complex and significantly increased processing costs, which has limited their applicability. Therefore, to address the shortcomings of existing technologies, there is a need to provide a Cu-Ni-Sn alloy with a short preparation process, high strength and toughness, and low tin content. Summary of the Invention

[0004] In order to overcome the deficiencies and shortcomings of the prior art, the primary purpose of the present invention is to provide a method for preparing a Cu-Ni-Sn alloy with high strength and toughness and low tin content.

[0005] The second object of the present invention is to provide a high-strength, toughness, and low-tin content Cu-Ni-Sn alloy prepared by the above preparation method.

[0006] The third object of the present invention is to provide a high-strength and low-tin content Cu-Ni-Sn alloy for use in the fields of aerospace, aviation, navigation and electronics industries.

[0007] The primary purpose of the present invention is achieved through the following technical solutions:

[0008] A high-strength, toughness, and low-tin content Cu-Ni-Sn alloy comprises the following components in weight percentage: 5.0-20.0% Ni, 1.0-6.0% Sn, 0-2.0% Mn, and the balance Cu, wherein impurities are negligible.

[0009] Preferably, the high-strength and toughness low-tin content Cu-Ni-Sn alloy comprises the following components in percentage by weight: Ni 15%, Sn 4%, Mn 0.6%, and the balance Cu.

[0010] The second object of the present invention is achieved through the following technical solutions:

[0011] A method for preparing a high-strength, toughness, and low-tin content Cu-Ni-Sn alloy comprises the following steps:

[0012] (1) Raw material preparation: Electrolytic copper, electrolytic nickel, industrial pure tin and manganese copper master alloy are mixed according to the designed ratio, wherein copper and nickel do not need to be burned out, the tin burnout rate is set to 5%, and the manganese copper master alloy burnout rate is set to 30%, and they are dried and surface degreased respectively;

[0013] (2) Melting: First, add electrolytic copper and electrolytic nickel to a medium frequency induction furnace, heat them to completely melt them, cool them to 1100-1200°C, add industrial pure tin and stir until they are completely melted, add manganese copper deoxidizer to deoxidize, then add the planned amount of Cu-Mn master alloy, heat them to 1100-1400°C, stir them until they are completely melted, keep them warm, and introduce argon gas for degassing to obtain an alloy melt;

[0014] (3) Casting: The alloy melt obtained in step (2) is slag-removed to obtain a mirror-like melt, which is allowed to stand. After the standing period, the mirror-like melt is poured into a metal mold, and an ingot is obtained after the solution solidifies;

[0015] (4) Post-treatment: The ingot obtained in step (3) is subjected to homogenization annealing, hot extrusion deformation, solution heat treatment and aging heat treatment to finally prepare a high-strength and toughness low-tin content Cu-Ni-Sn alloy.

[0016] Preferably, in step (1), Cu in the electrolytic copper is ≥99.95wt%, Ni in the electrolytic nickel is ≥99.90wt%, Sn in the industrial pure tin is ≥99.95wt%, Mn in the Cu-Mn master alloy is ≥17wt%, and the balance is Cu.

[0017] Preferably, in step (1), the raw material electrolytic copper block, electrolytic nickel block, industrial pure tin block and manganese-copper intermediate alloy block are wiped with cotton yarn to remove oil, and then placed in a heating furnace to be preheated to 150-250° C. for drying.

[0018] Preferably, the holding time in step (2) is 2 to 8 minutes, and the degassing time is 2 to 10 minutes.

[0019] Preferably, in step (2), the molten liquid surface is covered with charcoal during smelting, the crucible surface is insulated with asbestos, and a manganese-copper deoxidizer is used for deoxidation, wherein the Mn content of the manganese-copper deoxidizer is 17% to 17.5%, and the balance is Cu; the amount of the deoxidizer accounts for 0.3% to 0.4% of the total weight of the alloy melt.

[0020] Preferably, the standing time in step (3) is 1 to 10 minutes.

[0021] Preferably, in step (3), the metal mold is heated to 240-300°C using acetylene before casting, and the casting temperature is 1200-1300°C. After casting, the solution is naturally cooled under the action of gravity to obtain a metal ingot.

[0022] Preferably, in step (4), the homogenization temperature is 820°C-860°C, the surface oxide scale of the ingot is removed after annealing, and then the ingot is cut into extruded ingots of required specifications in a cutting machine, the temperature of hot extrusion deformation is 850°C-950°C, the extrusion ratio of hot extrusion deformation is 17.4, the solution heat treatment temperature is 800°C-900°C, and the aging heat treatment temperature is 350°C-400°C.

[0023] Preferably, the high-strength and toughness low-tin content Cu-Ni-Sn alloy in step (4) has a tensile strength of 690 to 800 MPa, a yield strength of 590 to 680 MPa, and an elongation of 10% to 15%.

[0024] Preferably, the high-strength and low-tin content Cu-Ni-Sn alloy in step (4) has a tensile strength of 692 MPa, a yield strength of 593 MPa, and an elongation of 13.5%.

[0025] Preferably, the high-strength and low-tin content Cu-Ni-Sn alloy in step (4) has a tensile strength of 788 MPa, a yield strength of 671 MPa, and an elongation of 11.5%.

[0026] The third object of the present invention is achieved through the following technical solutions:

[0027] A high-strength, toughness, low-tin content Cu-Ni-Sn alloy is used in the fields of aerospace, aviation, navigation, and electronics.

[0028] Working principle of the present invention:

[0029] The present invention determines the minimum tin content by consulting relevant literature and calculating the alloy phase diagram, and then obtains a low-tin content Cu-Ni-Sn alloy composition with optimal mechanical properties by adjusting the Ni element content in the alloy. Then, through microalloying means, the Mn element is added to the Cu-Ni-Sn alloy matrix. Under the action of the Mn element, the microsegregation phenomenon in the cast structure is significantly improved, the secondary dendrite spacing is refined, and the strength and plasticity of the alloy are improved. In the recast alloy, the Mn element can significantly improve the microstructure, inhibit the growth of discontinuous precipitation structure, refine the secondary dendrite spacing, and significantly improve the strength and plasticity of the cast alloy under the combined action of solid solution strengthening and fine grain strengthening. After the cast alloy undergoes homogenization annealing + hot extrusion + solution treatment + aging, the Mn element does not form a new second phase, but mainly dissolves into the structure and is enriched in the γ phase. During the aging process, it can significantly inhibit the formation and growth of discontinuous precipitation, delay the time of occurrence of the aging peak, and increase the peak hardness. Compared with the alloy without Mn addition, the tensile strength and yield strength are significantly improved while the plasticity remains basically unchanged.

[0030] The purpose of the present invention is to solve the problems of easy segregation of high-tin content Cu-Ni-Sn alloys, complex preparation process, and low comprehensive mechanical properties of low-tin content Cu-Ni-Sn alloys. A new composition and preparation process are provided to improve the comprehensive mechanical properties of low-tin content Cu-Ni-Sn alloys. Through a simple process, the alloy can be guaranteed to have high strength and high plasticity. The cast structure of Cu-Ni-Sn alloys prepared using traditional processes is severely segregated. The homogenization treatment temperature is high and the time is long, resulting in coarse grains after treatment, and it is difficult to completely eliminate segregation. In order to improve the mechanical properties, multiple large deformation processes (deformation amount > 90%) combined with multi-stage aging processes are often used after homogenization to improve the strength of the alloy, which can easily lead to a significant decrease in the plasticity of the alloy (<3%). Some studies use microalloying to improve the strength and plasticity of the alloy, but due to the small amount of trace elements added, it is easy to oxidize and burn. Vacuum melting is often used for preparation, which is not suitable for large-scale industrial production and difficult to meet industrial applications. The present invention reduces the tin content and the segregation problem in the alloy preparation process, avoids the use of complex heat treatment processes to eliminate segregation, and reduces the alloy cost. On the other hand, by adding an appropriate amount of trace elements, the grain size of the cast alloy is greatly reduced and the element distribution is made more uniform, which greatly suppresses the generation of discontinuous precipitation during the aging process and improves the mechanical properties of the alloy after aging, achieving the purpose of both ensuring strength and having good plasticity. The present invention has a short processing flow and low processing cost, is conducive to engineering applications, and is applicable to all Cu-Ni-Sn alloys. The comprehensive mechanical properties of the high-strength and toughness low-tin content Cu-Ni-Sn alloy provided by the present invention are significantly improved, making the alloy safer and more reliable during service.

[0031] The beneficial effects of the present invention compared to the prior art are as follows:

[0032] (1) The high-strength, toughness, and low-tin content Cu-Ni-Sn alloy prepared by the present invention has significantly refined grains in its cast microstructure, which are evenly distributed and more uniformly arranged; it has excellent mechanical properties, with a strength of up to 788 MPa and an elongation of 11.5%.

[0033] (2) The preparation process of the high-strength and toughness low-tin content Cu-Ni-Sn alloy described in the present invention is simpler and the production cost is lower, providing a new method for the large-scale application of Cu-Ni-Sn alloys.

[0034] (3) The preparation method of the high-strength and toughness low-tin content Cu-Ni-Sn alloy described in the present invention has important industrial application value. Through a simple process: "medium frequency casting + homogenization annealing + hot extrusion + solid solution + aging" and a simple composition: "Cu-Ni-Sn-Mn", a low-tin content Cu-Ni-Sn based alloy with mechanical properties comparable to those of the Cu-15Ni-8Sn alloy is prepared. After aging, the alloy obtains excellent properties of yield strength of 600-700MPa, tensile strength of 650-800MPa, and elongation of 10-15%. In addition, the secondary dendrite spacing can be significantly refined in the cast state, and the macro-segregation of the Sn element can be suppressed, which greatly reduces the application cost of the Cu-Ni-Sn alloy and provides new possibilities for the application of the Cu-Ni-Sn alloy. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art fall within the scope of protection of the present invention. The materials used in the examples of the present invention can all be purchased commercially.

[0036] Example 1

[0037] This embodiment designs a high-strength, toughness, and low-tin content Cu-Ni-Sn alloy, wherein the weight percentages of the components are Ni: 15.13 wt.%, Sn: 4.01 wt.%, Mn: 0.27 wt.%, and the balance is Cu.

[0038] The method for preparing a high-strength and low-tin content Cu-Ni-Sn alloy described in this embodiment includes the following steps:

[0039] (1) Raw material preparation: Prepare bulk electrolytic copper, bulk electrolytic nickel, bulk industrial pure tin and Cu-Mn master alloy in the following mass ratio of 80.7:15:4:0.3, wherein copper and nickel do not need to be configured for burnout, the tin burnout rate is configured to be 5%, and the manganese-copper master alloy burnout rate is 30%, and they are dried and surface degreasing treated respectively; Cu in the electrolytic copper is ≥99.95wt%, Ni in the electrolytic nickel is ≥99.90wt%, Sn in the pure tin is ≥99.95wt%, Mn in the Cu-Mn master alloy is ≥17wt%, and the balance is Cu.

[0040] (2) Melting: First, add block electrolytic copper and block electrolytic nickel to the medium frequency induction furnace, heat them to completely melt them, cool them to 1100-1200℃, and then add block industrial pure tin. Stir continuously until they are completely melted. Add a small amount of manganese copper deoxidizer for deoxidation, and then add manganese copper intermediate alloy configured according to the burn-out rate. After they are completely melted, introduce argon gas into the melt for 2-3 minutes for degassing; the melting temperature is controlled at 1100-1250℃ and lasts for about 50 minutes; during the heating and melting process, ensure that the molten liquid surface is completely covered by charcoal to isolate the air and reduce the oxidation of the melt. Deoxidize with manganese copper deoxidizer, the Mn content in the deoxidizer is 17-17.5%, and the amount of deoxidizer is 0.3-0.4% of the total weight of the solution. A tungsten steel stirring rod is used for stirring during the melting process, and a slag skimmer is used for skimming;

[0041] (3) Casting: After the surface of the solution is free of scum, the solution surface is opened and then left to stand for 1 minute to obtain a mirror-like melt. The iron mold is preheated to 240-260°C with an acetylene torch in advance, and the melt is directly cast into the iron mold. The casting temperature is controlled at 1200°C. After cooling until the mirror-like melt solidifies, an ingot is obtained.

[0042] (4) Based on the ingot prepared by melting and casting, homogenization annealing → hot extrusion deformation → solution heat treatment → aging heat treatment are carried out. The homogenization annealing temperature is 840℃, the hot extrusion deformation temperature is 900℃, the extrusion ratio is 17.4, the solution treatment temperature is 820℃, and the aging heat treatment temperature is 400℃.

[0043] The finished product obtained in this embodiment was tested by room temperature tensile test, and the results showed that the tensile strength reached 692 MPa, the yield strength reached 593 MPa, and the elongation reached 13.5%.

[0044] Example 2

[0045] This embodiment designs a high-strength, toughness, and low-tin content Cu-Ni-Sn alloy, wherein the weight percentages of the components are Ni: 15.07 wt.%, Sn: 4.01 wt.%, Mn: 0.62 wt.%, and the balance is Cu.

[0046] The high-strength and low-tin content Cu-Ni-Sn alloy described in this embodiment includes the following steps:

[0047] (1) Raw material preparation: Prepare bulk electrolytic copper, bulk electrolytic nickel, bulk industrial pure tin and Cu-Mn master alloy in the following mass ratio of 80.4:15:4:0.6, wherein copper and nickel do not need to be configured for burnout, the tin burnout rate is configured to be 5%, and the manganese-copper master alloy burnout rate is 30%, and they are dried and surface degreasing treated respectively; Cu in the electrolytic copper is ≥99.95wt%, Ni in the electrolytic nickel is ≥99.90wt%, Sn in the pure tin is ≥99.95wt%, Mn in the Cu-Mn master alloy is ≥17wt%, and the balance is Cu.

[0048] (2) Melting: First, add block electrolytic copper and block electrolytic nickel to the medium frequency induction furnace, heat them to completely melt them, cool them to 1100-1200℃, and then add block industrial pure tin. Stir continuously until they are completely melted. Add a small amount of manganese copper deoxidizer for deoxidation, and then add manganese copper intermediate alloy configured according to the burn-out rate. After they are completely melted, pass argon gas into the melt for 2-3 minutes for degassing. The melting temperature is controlled at 1100-1250℃ and lasts for about 50 minutes. During the heating and melting process, ensure that the molten liquid surface is completely covered by charcoal to isolate the air and reduce the oxidation of the melt. Deoxidize with manganese copper deoxidizer. The Mn content in the deoxidizer is 17-17.5%, and the amount of deoxidizer is 0.3-0.4% of the total weight of the solution. A tungsten steel stirring rod is used for stirring during the melting process, and a slag skimmer is used to skim off slag.

[0049] (3) Casting: After the solution surface is free of scum, the solution surface is opened and mirror-like, then left to stand for 1 minute. The iron mold is preheated to 240-260°C with an acetylene torch in advance, and the melt is directly cast into the iron mold. The casting temperature is controlled at 1200°C. After cooling until the melt solidifies, an ingot is obtained.

[0050] (4) Based on the ingot prepared by melting and casting, homogenization annealing → hot extrusion deformation → solution heat treatment → aging heat treatment are carried out. The homogenization annealing temperature is 840℃, the hot extrusion deformation temperature is 900℃, the extrusion ratio is 17.4, the solution treatment temperature is 820℃, and the aging heat treatment temperature is 400℃.

[0051] The finished product obtained in this embodiment was tested by room temperature tensile test, and the results showed that the tensile strength reached 788 MPa, the yield strength reached 671 MPa, and the elongation reached 11.5%.

[0052] Comparative Example 1

[0053] This comparative example is a Cu-15Ni-4Sn alloy without adding Mn element, which is composed of the following components in percentage by weight: Ni 14.33%; Sn 3.94%; and the balance being Cu.

[0054] The Cu-15Ni-4Sn alloy without adding Mn element in this comparative example was prepared by the following method steps:

[0055] (1) Raw material preparation: Prepare bulk electrolytic copper, bulk electrolytic nickel, bulk industrial pure tin and Cu-Mn master alloy in the following mass ratio of 81:15:4, wherein copper and nickel do not need to be burned out, and the tin burnout rate is set to 5%, and dry and degrease the raw materials respectively; Cu in the electrolytic copper is ≥99.95wt%, Ni in the electrolytic nickel is ≥99.90wt%, Sn in the pure tin is ≥99.95wt%, and the balance is Cu.

[0056] (2) Melting: First, add bulk electrolytic copper and bulk electrolytic nickel to the medium frequency induction furnace, heat them to completely melt them, and then cool them to 1100-1200℃ before adding bulk industrial pure tin. Stir continuously until they are completely melted. After they are completely melted, introduce argon gas into the melt for 2-3 minutes to degas. The melting temperature is controlled at 1100-1250℃ and lasts for about 50 minutes. During the heating and melting process, ensure that the molten liquid surface is completely covered by charcoal to isolate the air and reduce the oxidation of the melt. Deoxidize with a manganese copper deoxidizer. The Mn content in the deoxidizer is 17-17.5%, and the amount of deoxidizer is 0.3-0.4% of the total weight of the solution. A tungsten steel stirring rod is used for stirring during the melting process, and a slag skimmer is used to skim off slag.

[0057] (3) Casting: After the solution surface is free of scum, the solution surface is opened and then left to stand for 1 minute until it is mirror-like. The iron mold is preheated to 240-260°C with an acetylene torch in advance. The melt is directly cast into the iron mold. The casting temperature is controlled at 1200°C. The ingot is obtained after cooling until the melt solidifies.

[0058] (4) Based on the ingot prepared by melting and casting, homogenization annealing → hot extrusion deformation → solution heat treatment → aging heat treatment is performed. The homogenization annealing temperature is 840°C, the hot extrusion deformation temperature is 900°C, the extrusion ratio is 17.4, the solution heat treatment temperature is 820°C, and the aging heat treatment temperature is 400°C;

[0059] The finished product obtained in this comparative example was tested by a room temperature tensile test, and the results showed that the tensile strength reached 675 MPa, the yield strength reached 577 MPa, and the elongation reached 11.4%.

[0060] Comparative Example 2

[0061] This comparative example is a Cu-15Ni-4Sn alloy with excessive addition of Mn element, which is composed of the following components in percentage by weight: Ni 15.11%, Sn 4.03%, Mn 0.92%, and the balance being Cu.

[0062] The Cu-15Ni-4Sn alloy with excessive addition of Mn element in this comparative example was prepared by the following method steps:

[0063] (1) Raw material preparation: prepare bulk electrolytic copper, bulk electrolytic nickel, bulk industrial pure tin and Cu-Mn master alloy in the following mass ratio of 80.1:15:4:0.9, wherein copper and nickel do not need to be configured for burnout, the tin burnout rate is configured to be 5%, and the manganese-copper master alloy burnout rate is 30%, and they are dried and surface degreasing treated respectively; Cu in the electrolytic copper is ≥99.95wt%, Ni in the electrolytic nickel is ≥99.90wt%, Sn in the pure tin is ≥99.95wt%, Mn in the Cu-Mn master alloy is ≥17wt%, and the balance is Cu.

[0064] (2) Melting: First, add block electrolytic copper and block electrolytic nickel to the medium frequency induction furnace, heat them to completely melt them, cool them to 1100-1200℃, and then add block industrial pure tin. Stir continuously until they are completely melted. Add a small amount of manganese copper deoxidizer for deoxidation, and then add manganese copper intermediate alloy configured according to the burn-out rate. After they are completely melted, introduce argon gas into the melt for 2-3 minutes for degassing; the melting temperature is controlled at 1100-1250℃ and lasts for about 50 minutes; during the heating and melting process, ensure that the molten liquid surface is completely covered by charcoal to isolate the air and reduce the oxidation of the melt. Deoxidize with manganese copper deoxidizer, the Mn content in the deoxidizer is 17-17.5%, and the amount of deoxidizer is 0.3-0.4% of the total weight of the solution. A tungsten steel stirring rod is used for stirring during the melting process, and a slag skimmer is used for skimming;

[0065] (3) Casting: After the solution surface is free of scum, pry the solution surface to a mirror-like state and let it stand for 1 minute. Preheat the iron mold to 240-260°C with an acetylene torch in advance, and cast the melt directly into the iron mold. The casting temperature is controlled at 1200°C. Cool until the melt solidifies to obtain an ingot.

[0066] (4) Based on the ingot prepared by melting and casting, homogenization annealing → hot extrusion deformation → solution heat treatment → aging heat treatment are carried out. The homogenization annealing temperature is 840℃, the hot extrusion deformation temperature is 900℃, the extrusion ratio is 17.4, the solution heat treatment temperature is 820℃, and the aging heat treatment temperature is 400℃.

[0067] The finished product obtained in this comparative example was tested by a room temperature tensile test, and the results showed that the tensile strength reached 654 MPa, the yield strength reached 547 MPa, and the elongation reached 10.5%.

[0068] The present invention provides a Cu-Ni-Sn alloy with excellent performance. Examples 1 and 2, for example, exhibit tensile strengths greater than 690 MPa, yield strengths greater than 590 MPa, and elongations greater than 10%, all exhibiting excellent ductility. The present invention provides a Cu-Ni-Sn alloy with excellent performance, exhibiting good toughness and uniform mechanical properties. The present invention is suitable for industrial production and can meet the needs of the aerospace, aviation, marine, and electronics industries for high-strength and tough elastic materials.

[0069] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A high-strength, toughness, low-tin content Cu-Ni-Sn alloy, characterized in that: The invention comprises the following components in percentage by weight: Ni 5.0-20.0%, Sn 1.0-6.0%, Mn 0-2.0%, and the balance Cu.

2. The high strength and toughness low tin content Cu-Ni-Sn alloy according to claim 1, characterized in that: The high-strength, toughness, and low-tin content Cu-Ni-Sn alloy comprises the following components in percentage by weight: 15% Ni, 4% Sn, 0.6% Mn, and the balance Cu.

3. A method for preparing the high-strength and low-tin content Cu-Ni-Sn alloy according to any one of claims 1 or 2, characterized in that: The following steps are included: (1) Raw material preparation: Electrolytic copper, electrolytic nickel, industrial pure tin and manganese copper master alloy are mixed according to the designed ratio, wherein copper and nickel do not need to be burned out, the tin burnout rate is set to 5%, and the manganese copper master alloy burnout rate is set to 30%, and they are dried and surface degreased respectively; (2) Melting: First, add electrolytic copper and electrolytic nickel to a medium frequency induction furnace, heat them to completely melt them, cool them to 1100-1200°C, add industrial pure tin and stir until they are completely melted, add manganese copper deoxidizer to deoxidize, then add the planned amount of Cu-Mn master alloy, heat them to 1100-1400°C, stir them until they are completely melted, keep them warm, and introduce argon gas for degassing to obtain an alloy melt; (3) Casting: The alloy melt obtained in step (2) is slag-removed to obtain a mirror-like melt, which is allowed to stand. After the standing period, the mirror-like melt is poured into a metal mold, and an ingot is obtained after the solution solidifies; (4) Post-treatment: The ingot obtained in step (3) is subjected to homogenization annealing, hot extrusion deformation, solution heat treatment and aging heat treatment to finally prepare a high-strength and toughness low-tin content Cu-Ni-Sn alloy.

4. The method for preparing the high-strength and low-tin content Cu-Ni-Sn alloy according to claim 3, characterized in that: In step (1), the electrolytic copper contains Cu≥99.95wt%, the electrolytic nickel contains Ni≥99.90wt%, the industrial pure tin contains Sn≥99.95wt%, the Cu-Mn master alloy contains Mn≥17wt%, and the balance is Cu.

5. The method for preparing the high-strength and low-tin content Cu-Ni-Sn alloy according to claim 3, characterized in that: The holding time in step (2) is 2 to 8 minutes, and the degassing time is 2 to 10 minutes.

6. The method for preparing the high-strength and low-tin content Cu-Ni-Sn alloy according to claim 3, characterized in that: In step (2), during smelting, the molten liquid surface is covered with charcoal, the crucible surface is insulated with asbestos, and a manganese copper deoxidizer is used for deoxidation, wherein the Mn content of the manganese copper deoxidizer is 17% to 17.5% and the balance is Cu; the amount of the deoxidizer accounts for 0.3% to 0.4% of the total weight of the alloy melt.

7. The method for preparing the high-strength and low-tin content Cu-Ni-Sn alloy according to claim 3, characterized in that: In step (3), the metal mold is heated to 240-300° C. using acetylene before casting, and the casting temperature is 1200-1300° C. After casting, the solution is naturally cooled under the action of gravity to obtain a metal ingot.

8. The method for preparing the high-strength and low-tin content Cu-Ni-Sn alloy according to claim 3, characterized in that: In step (4), the homogenization temperature is 820°C-860°C, the surface oxide scale of the ingot is removed after annealing, and then the ingot is cut into extruded ingots of required specifications in a cutting machine, the temperature of hot extrusion deformation is 850°C-950°C, the extrusion ratio of hot extrusion deformation is 17.4, the solution heat treatment temperature is 800°C-900°C, and the aging heat treatment temperature is 350°C-400°C.

9. The method for preparing the high-strength and low-tin content Cu-Ni-Sn alloy according to claim 3, characterized in that: The high-strength and low-tin content Cu-Ni-Sn alloy in step (4) has a tensile strength of 690 to 800 MPa, a yield strength of 590 to 680 MPa, and an elongation of 10% to 15%.

10. Use of the high-strength, toughness, low-tin content Cu-Ni-Sn alloy according to any one of claims 1 or 2 in the fields of aerospace, aviation, navigation and electronics industries.