Preparation method of high-strength and high-plasticity mixed crystal copper alloy

Abstract

The invention discloses a preparation method of a high-strength and high-plasticity mixed crystal copper alloy, and belongs to the technical field of copper alloy manufacturing. The method comprises the following steps: heating a copper alloy in two crucibles to a molten state; adding aluminum oxide powder into one of the crucibles; transferring the molten copper alloy in the crucible into a funnel of injection molding equipment, and enabling the alloy to flow into an atomization device; a high-pressure inert gas atomization process and a low-pressure inert gas atomization process are respectively utilized, and solid-liquid two-phase particle jet flow is formed through double-flow atomization; spraying the jet flow to a substrate, and cooling to form a copper alloy blank; and post-treatment is conducted according to the copper alloy element proportion. The mixed crystal copper alloy prepared through the double-flow atomization method is excellent in plasticity and strength performance, the contradiction that the plasticity and the strength in the copper alloy cannot be improved at the same time can be well solved, and the mixed crystal copper alloy has wide application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of copper alloy manufacturing, and specifically relates to a method for preparing a high-strength and plastic mixed-crystal copper alloy. Background Art

[0002] Copper itself is a metal with good ductility, but its strength is relatively low. Traditional copper strengthening methods, such as alloying and heat treatment, can improve the strength of copper alloys, but often at the expense of plasticity. This is because the strengthening process may increase defects inside the copper, such as dislocations and grain boundaries, which will become the origin of cracks when subjected to external forces, thereby reducing the plasticity of the copper alloy. In addition, the strength and plasticity of copper alloys are also affected by the processing technology. For example, nano twins can be introduced into copper alloys through large plastic deformation and subsequent annealing, which helps to improve plasticity. However, if the annealing treatment is improper, it may cause grain growth and reduce the number of twins, thereby reducing the strength and plasticity of the copper alloy. The contradiction between the strength and plasticity of copper alloys limits the application of copper alloys. Therefore, it is necessary to improve the plasticity and strength of copper alloys at the same time. At present, traditional deformation strengthening, heat treatment and other methods are difficult to overcome the inverted relationship between strength and plasticity of copper alloys, which greatly limits the further application of high-strength and plastic copper alloys. The copper alloy with mixed crystal structure can effectively solve the contradiction between strength and plasticity of copper alloy due to its unique microstructure, and comprehensively improve the performance of copper alloy. By preparing the mixed crystal structure of copper alloy grains of different sizes, the copper alloy has both high strength and plasticity, thus developing the mixed crystal copper alloy structural material.

[0003] At present, there are two methods for preparing mixed crystal copper alloy structural materials: one-step method and two-step method. The one-step method can also be divided into two types: annealing coarsening and local refinement. Annealing coarsening refers to first obtaining a homogeneous structure through large plastic deformation or traditional hot deformation treatment, and then performing subsequent heat treatment on the homogeneous structure copper alloy, so that a part of the grains in the homogeneous copper alloy grows, thereby forming a multi-scale grain structure in the copper alloy. The two-step method refers to a method in which finer powder particles are first prepared, and then particles of different particle sizes are pressurized and sintered to obtain a bulk mixed crystal copper alloy, such as spark plasma sintering and hot pressing sintering. In the process of making mixed crystal copper alloy structural materials by these two methods, the copper alloy is relatively easy to oxidize, the preparation cost is high, the influence of micro-segregation and impurities is large, and the grains of the prepared mixed crystal copper alloy are relatively large and the structure is uneven.

[0004] Therefore, how to use appropriate technology to prepare mixed crystal copper alloy becomes the key to further improve the performance of mixed crystal copper alloy. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing a high-strength and high-ductility mixed-crystal copper alloy, so as to solve the problem of large grains and uneven structure of the mixed-crystal copper alloy in the background technology.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing a high-strength and ductile mixed crystal copper alloy comprises the following steps:

[0008] Step 1, heating the copper alloy in two crucibles to a molten state;

[0009] Step 2, adding alumina powder into one of the crucibles;

[0010] Step 3, the molten copper alloy in the crucible is transferred to the funnel of the injection molding equipment, and the alloy flows into the atomization device; high-pressure inert gas atomization and low-pressure inert gas atomization processes are used respectively, and double-flow atomization forms a solid-liquid two-phase particle jet flow;

[0011] Step 4, the jet stream is sprayed onto the substrate and cooled to form a copper alloy blank;

[0012] Step 5: Perform post-processing according to the ratio of copper alloy elements.

[0013] As a further solution of the present invention, in step 1, the heating method is to use an induction melting furnace for heating.

[0014] As a further solution of the present invention, in step 2, the amount of alumina powder added to the crucible is 0.1%-1.5% of the amount of copper alloy in the crucible.

[0015] As a further embodiment of the present invention, in step 3, the inert gas is nitrogen.

[0016] As a further solution of the present invention, in step 3, two crucibles are respectively connected to the funnel of the injection molding equipment, and the funnels are respectively provided with spray plates, one spray plate inputs high-pressure inert gas, and the other spray plate inputs low-pressure inert gas, the pressure of the high-pressure inert gas is 12-15MPa, and the pressure of the low-pressure inert gas is 1-2MPa.

[0017] As a further embodiment of the present invention, the weight ratio of the molten copper alloy atomized by the high-pressure inert gas to the molten copper alloy atomized by the low-pressure inert gas is 1-2:1.

[0018] As a further solution of the present invention, alumina powder is added to the molten copper alloy atomized by high-pressure inert gas to prevent the recrystallization and growth of fine grains, while coarse grains may recrystallize and grow, which can make the mixed crystal structure more stable.

[0019] As a further solution of the present invention, the spray disc adopts V-shaped spray or conical spray.

[0020] As a further solution of the present invention, in step 4, the jet is sprayed onto the preheated substrate under the action of the atomizing gas to form a rapidly solidified deposition layer; then, by regulating the substrate temperature and cooling rate, combined with the dynamic compaction effect during the deposition process, the deposition layer is densified layer by layer, and finally a high-density copper alloy billet is formed.

[0021] As a further solution of the present invention, in step 5, for preparing the mixed crystal copper-nickel-silicon alloy, the post-treatment includes hot rolling, solution treatment, cold rolling, and aging treatment in sequence.

[0022] As a further solution of the present invention, in step 5, for preparing the mixed crystal copper-zinc-manganese-silicon-nickel (brass) alloy, the post-treatment includes homogenization, hot rolling, and cold rolling treatment in sequence.

[0023] As a further solution of the present invention, in step 5, for preparing the mixed crystal copper-chromium-zirconium alloy, the post-treatment includes hot rolling, solution treatment, and aging treatment in sequence.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention provides a method for preparing a high-strength and plastic mixed-crystal copper alloy. A mixed-crystal copper alloy blank is prepared by a dual-stream simultaneous atomization method. Only one processing is required to obtain a semi-finished mixed-crystal copper alloy, which can greatly reduce production costs. In addition, due to the effect of high-pressure gas, the structure formed by the deposition of atomized copper alloy droplets is finer and more uniform, which suppresses the influence of micro-segregation and impurities. The possibility of mixed-crystal copper alloy being oxidized during the multi-link preparation process is reduced, and the preparation cost is reduced. Since the solidification rate of the copper alloy is greatly improved during the dual-stream atomization process, the prepared mixed-crystal copper alloy has finer grains, a more uniform structure, and can suppress macro- and micro-segregation in the mixed-crystal copper alloy, which is conducive to obtaining better performance. The particle size of the powder during the atomization process is usually small, which helps to achieve grain refinement in the preparation process of mixed crystal copper alloys. Fine grains can effectively hinder the movement of dislocations, thereby improving the strength and toughness of the copper alloy, and can achieve uniform distribution of the internal structure of the copper alloy, which is very beneficial for maintaining the mixed crystal structure. The uniform structure can reduce stress concentration inside the material and improve the overall performance of the copper alloy. It can affect the phase change process of the copper alloy, thereby helping to maintain the mixed crystal structure and has good thermal stability, which helps to maintain the mixed crystal structure in high-temperature applications.

[0026] 2. The mixed crystal copper alloy prepared by the present invention has excellent plasticity and strength, can well solve the contradiction that the plasticity and strength of the copper alloy cannot be improved at the same time, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below in conjunction with the accompanying drawings.

[0028] Figure 1 Schematic diagram of the present invention using a double-flow atomization process to prepare a high-strength and plastic mixed-crystal copper alloy;

[0029] Figure 2 is a TEM image of a mixed crystal copper alloy billet after double-flow atomization spray forming in the process of preparing a high-strength and plastic mixed crystal copper alloy according to Example 1 of the present invention;

[0030] Figure 3 is a TEM image of a mixed crystal copper alloy billet after double-flow atomization spray forming in the process of preparing a high-strength and plastic mixed crystal copper alloy according to Example 2 of the present invention;

[0031] Figure 4 is a TEM image of a mixed crystal copper alloy billet after double-flow atomization spray forming in the process of preparing a high-strength and plastic mixed crystal copper alloy according to Example 3 of the present invention;

[0032] Figure 5 Schematic diagram of the specific dimensions of the uniaxial tensile specimen. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] See also Figure 1 A method for preparing a high-strength and ductile mixed-crystal copper alloy (Cu-2.1Ni-0.9Si alloy) comprises the following steps:

[0036] Step 1, respectively connect two crucibles to the funnel of the injection molding equipment, and the funnels are respectively provided with spray plates, one spray plate inputs high-pressure nitrogen, and the other spray plate inputs low-pressure nitrogen; divide the copper alloy into 2 parts according to a weight ratio of 1:1.5, add 1 part by weight of the copper alloy to the crucible connected to the low-pressure nitrogen side, and add 1.5 parts by weight of the copper alloy to the crucible connected to the high-pressure nitrogen side, and heat them to a molten state using an induction melting furnace respectively;

[0037] Step 2, adding 0.8% alumina powder into the crucible connected to the high-pressure nitrogen side;

[0038] Step 3, the molten copper alloy flows into the atomizing device, and is atomized by double flow to form a droplet jet flow of solid-liquid two-phase particles under the action of low-pressure nitrogen atomization of 1.5 MPa and high-pressure nitrogen atomization of 12 MPa respectively;

[0039] Step 4: The double-flow atomized jet is sprayed onto the preheated substrate to form a rapidly solidified deposition layer; then, by adjusting the substrate temperature and cooling rate, combined with the dynamic compaction effect during the deposition process, the deposition layer is densified layer by layer, and finally a high-density mixed crystal copper alloy blank is formed. The transmission electron microscope (TEM) image is shown in FIG. Figure 2 As shown;

[0040] Step 5: hot rolling, solution treatment, cold rolling and aging treatment are sequentially performed on the blank.

[0041] Example 2

[0042] See also Figure 1 A method for preparing a high-strength and ductile mixed-crystal copper alloy (Cu-34Zn-1.3Mn-0.5Si-0.6Ni alloy) comprises the following steps:

[0043] Step 1, respectively connect two crucibles to the funnel of the injection molding equipment, and the funnels are respectively provided with spray plates, one spray plate inputs high-pressure nitrogen, and the other spray plate inputs low-pressure nitrogen; divide the copper alloy into 2 parts according to a weight ratio of 1:1.5, add 1 part by weight of the copper alloy to the crucible connected to the low-pressure nitrogen side, and add 1.5 parts by weight of the copper alloy to the crucible connected to the high-pressure nitrogen side, and heat them to a molten state using an induction melting furnace respectively;

[0044] Step 2, adding 0.8% alumina powder into the crucible connected to the high-pressure nitrogen side;

[0045] Step 3, the molten copper alloy flows into the atomizing device, and is atomized by double flow to form a droplet jet flow of solid-liquid two-phase particles under the action of low-pressure nitrogen atomization of 1.5 MPa and high-pressure nitrogen atomization of 12 MPa respectively;

[0046] Step 4: The jet is sprayed onto the preheated substrate to form a rapidly solidified deposition layer; then, by adjusting the substrate temperature and cooling rate, combined with the dynamic compaction effect during the deposition process, the deposition layer is densified layer by layer, and finally a high-density mixed crystal copper alloy blank is formed, as shown in the TEM image. Figure 3 As shown;

[0047] Step 5: The blank is subjected to homogenization, hot rolling and cold rolling treatments in sequence.

[0048] Example 3

[0049] See also Figure 1 , a method for preparing a high-strength and ductile mixed-crystal copper alloy (Cu-0.8Cr-0.16Zr alloy), comprising the following steps:

[0050] Step 1, respectively connect two crucibles to the funnel of the injection molding equipment, and the funnels are respectively provided with spray plates, one spray plate inputs high-pressure nitrogen, and the other spray plate inputs low-pressure nitrogen; divide the copper alloy into 2 parts according to a weight ratio of 1:1.5, add 1 part by weight of the copper alloy to the crucible connected to the low-pressure nitrogen side, and add 1.5 parts by weight of the copper alloy to the crucible connected to the high-pressure nitrogen side, and heat them to a molten state using an induction melting furnace respectively;

[0051] Step 2, adding 0.8% alumina powder into the crucible connected to the high-pressure nitrogen side;

[0052] Step 3, the molten copper alloy flows into the atomizing device, and is atomized by double flow to form a droplet jet flow of solid-liquid two-phase particles under the action of low-pressure nitrogen atomization of 1.5 MPa and high-pressure nitrogen atomization of 12 MPa respectively;

[0053] Step 4: The jet is sprayed onto the preheated substrate to form a rapidly solidified deposition layer; then, by adjusting the substrate temperature and cooling rate, combined with the dynamic compaction effect during the deposition process, the deposition layer is densified layer by layer, and finally a high-density mixed crystal copper alloy blank is formed, as shown in the TEM image. Figure 4 As shown;

[0054] Step 5: hot rolling, solution treatment and aging treatment are performed on the blank in sequence.

[0055] Example 4

[0056] See also Figure 1 , a method for preparing a high-strength and ductile mixed-crystal copper alloy (Cu-2.1Ni-0.9Si alloy), which differs from Example 1 in that the weight ratio of the copper alloy in the crucible connected to the low-pressure nitrogen side and the crucible connected to the high-pressure nitrogen side is 1:1, and the other steps and parameters remain the same.

[0057] Example 5

[0058] See also Figure 1 , a method for preparing a high-strength and ductile mixed-crystal copper alloy (Cu-2.1Ni-0.9Si alloy), which differs from Example 1 in that the weight ratio of the copper alloy in the crucible connected to the low-pressure nitrogen side and the crucible connected to the high-pressure nitrogen side is 1:2, and the other steps and parameters remain the same.

[0059] Example 6

[0060] See also Figure 1 , a method for preparing a high-strength and ductile mixed-crystal copper alloy (Cu-2.1Ni-0.9Si alloy), which is different from Example 1 in that the proportion of alumina powder added to the crucible connected to the high-pressure nitrogen side is 0.2%, and the other steps and parameters remain the same.

[0061] Example 7

[0062] See also Figure 1 , a method for preparing a high-strength and ductile mixed-crystal copper alloy (Cu-2.1Ni-0.9Si alloy), which is different from Example 1 in that the proportion of alumina powder added to the crucible connected to the high-pressure nitrogen side is 1.5%, and the other steps and parameters remain the same.

[0063] Example 8

[0064] See also Figure 1 , a method for preparing a high-strength and ductile mixed-crystal copper alloy (Cu-2.1Ni-0.9Si alloy), which is different from Example 1 in that the high-pressure inert gas pressure is 15MPa, the low-pressure inert gas pressure is 1MPa, and the other steps and parameters remain the same.

[0065] Example 9

[0066] See also Figure 1 , a method for preparing a high-strength and ductile mixed-crystal copper alloy (Cu-2.1Ni-0.9Si alloy), which is different from Example 1 in that the high-pressure inert gas pressure is 13MPa, the low-pressure inert gas pressure is 2MPa, and the other steps and parameters remain the same.

[0067] Comparative Example 1

[0068] The copper alloy (Cu-2.1Ni-0.9Si alloy) is prepared by a conventional melting and casting process, which specifically includes the following steps: in a vacuum furnace, a copper-nickel-silicon block with a certain proportion is heated to 1000°C, and after the copper-nickel-silicon block is melted, it is naturally cooled to room temperature (25-30°C).

[0069] Comparative Example 2

[0070] See also Figure 1 , a method for preparing a mixed crystal copper alloy (Cu-2.1Ni-0.9Si alloy), which is different from Example 1 in that the nitrogen pressure input by the two spray plates is set to 12Mpa, and the other steps and parameters remain the same; specifically comprising the following steps:

[0071] Step 1, connecting two crucibles to the funnel of the injection molding equipment respectively, and setting spray plates on the funnels respectively, and inputting nitrogen into the two spray plates; dividing the copper alloy into two parts according to the weight ratio of 1:1.5, putting them into the crucibles respectively, and heating them to a molten state by an induction melting furnace respectively;

[0072] Step 2, adding 0.8% of alumina powder into 1.5 parts by weight of the crucible;

[0073] Step 3, the molten copper alloy flows into the atomizing device, and is atomized by double flow to form a droplet jet flow of solid-liquid two-phase particles under the action of a high-pressure nitrogen atomizing process of 12 MPa;

[0074] Step 4, the jet flow is sprayed onto the preheated substrate to form a rapidly solidified deposition layer; then, by adjusting the substrate temperature and cooling rate, combined with the dynamic compaction effect during the deposition process, the deposition layer is densified layer by layer to obtain a copper alloy blank;

[0075] Step 5: hot rolling, solution treatment, cold rolling and aging treatment are sequentially performed on the blank.

[0076] Comparative Example 3

[0077] See also Figure 1 , a method for preparing a mixed crystal copper alloy (Cu-2.1Ni-0.9Si alloy), which is different from Example 1 in that the nitrogen pressure input by the two spray plates is set to 1.5Mpa, and the other steps and parameters remain the same; specifically comprising the following steps:

[0078] Step 1, connecting two crucibles to the funnel of the injection molding equipment respectively, and setting spray plates on the funnels respectively, and inputting nitrogen into the two spray plates; dividing the copper alloy into two parts according to the weight ratio of 1:1.5, putting them into the crucibles respectively, and heating them to a molten state by an induction melting furnace respectively;

[0079] Step 2, adding 0.8% of alumina powder into 1.5 parts by weight of the crucible;

[0080] Step 3, the molten copper alloy flows into the atomizing device, and is atomized by double flow to form a droplet jet flow of solid-liquid two-phase particles under the action of a low-pressure nitrogen atomizing process of 1.5 MPa;

[0081] Step 4, the jet flow is sprayed onto the preheated substrate to form a rapidly solidified deposition layer; then, by adjusting the substrate temperature and cooling rate, combined with the dynamic compaction effect during the deposition process, the deposition layer is densified layer by layer to obtain a copper alloy blank;

[0082] Step 5: hot rolling, solution treatment, cold rolling and aging treatment are sequentially performed on the blank.

[0083] Comparative Example 4

[0084] See also Figure 1 , a method for preparing a high-strength and ductile mixed-crystal copper alloy (Cu-2.1Ni-0.9Si alloy), which differs from Example 1 in that alumina powder is not added to the crucible connected to the high-pressure nitrogen side, and the other steps and parameters remain the same.

[0085] The parameters in the above embodiments and comparative examples are summarized in Table 1.

[0086] Table 1

[0087]

[0088] The copper alloy blanks prepared in Examples 1 to 9 and Comparative Examples 1 to 4 were subjected to tensile tests at room temperature. The tensile machine model was an AG-100KNXp l us electronic universal material testing machine. The tensile specimens were prepared using an electric spark wire cutting machine. The specific dimensions of the unidirectional tensile specimens are as follows: Figure 5 As shown, the gauge length is 12 mm, the working area width is 4 mm, the surface and side of the tensile specimen are polished with sandpaper until they are bright and smooth, the tensile loading speed is 1 mm / min, and the tensile strength and elongation can be obtained; the test results are shown in Table 2.

[0089] Table 2

[0090] Tensile strength / MPa Elongation Example 1 800 12％ Example 2 660 18％ Example 3 720 16％ Example 4 780 11.8％ Example 5 790 11.6％ Example 6 786 11.8％ Example 7 797 12.3％ Example 8 807 11.7％ Example 9 798 12.4％ Comparative Example 1 300 8％ Comparative Example 2 456 7.8％ Comparative Example 3 347 8.7％ Comparative Example 4 725 10.6％

[0091] As can be seen from Table 2, compared with Example 1 and Comparative Example 1, the tensile strength and elongation of the copper-nickel-silicon alloy prepared by the conventional method are far inferior to the mixed-crystal copper-nickel-silicon alloy prepared by the double-flow atomization process of the present invention. Compared with Example 1 and Comparative Example 2, both flows are high-pressure atomization, which makes the grains too fine, resulting in the phenomenon of fine grain recrystallization and growth; compared with Example 1 and Comparative Example 2, both flows are low-pressure atomization, resulting in the alloy grains produced by gas atomization being larger, making the density of the copper alloy blank poor. Compared with Example 1 and Comparative Example 4, when aluminum oxide powder is not added to the high-pressure end copper alloy, fine grains may recrystallize and grow into coarse grains, and the coarse grains may further crystallize and grow, resulting in an unstable mixed crystal structure. Therefore, by adopting the process of the present invention, the prepared mixed-crystal copper alloy has finer grains, more uniform structure, and can suppress the macroscopic and microscopic segregation in the mixed-crystal copper alloy, which can effectively improve the strength and plasticity of the copper-nickel-silicon alloy at the same time.

[0092] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0093] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-strength and ductile mixed crystal copper alloy, characterized in that: The following steps are involved: Step 1, heating the copper alloy in two crucibles to a molten state; Step 2, adding alumina powder into one of the crucibles; Step 3, the molten copper alloy in the crucible is transferred to the funnel of the injection molding equipment, and the alloy flows into the atomization device; high-pressure inert gas atomization and low-pressure inert gas atomization processes are used respectively, and double-flow atomization forms a solid-liquid two-phase particle jet flow; Step 4, the jet stream is sprayed onto the substrate and cooled to form a copper alloy blank; Step 5: Perform post-processing according to the ratio of copper alloy elements.

2. The method for preparing a high-strength and ductile mixed crystal copper alloy according to claim 1, characterized in that: In step 1, the heating method is to use an induction melting furnace for heating.

3. The method for preparing a high-strength and ductile mixed crystal copper alloy according to claim 1, characterized in that: In step 2, the amount of alumina powder added to the crucible is 0.1%-1.5% of the amount of copper alloy in the crucible.

4. The method for preparing a high-strength and ductile mixed crystal copper alloy according to claim 1, characterized in that: In step 3, the inert gas is nitrogen.

5. The method for preparing a high-strength and ductile mixed crystal copper alloy according to claim 1, characterized in that: In step 3, two crucibles are respectively connected to the funnel of the injection molding equipment, and the funnels are respectively provided with spray plates, one spray plate inputs high-pressure inert gas, and the other spray plate inputs low-pressure inert gas. The pressure of the high-pressure inert gas is 12-15MPa, and the pressure of the low-pressure inert gas is 1-2MPa.

6. The method for preparing a high-strength and ductile mixed crystal copper alloy according to claim 1, characterized in that: In step 3, the weight ratio of the molten copper alloy atomized by the high-pressure inert gas to the molten copper alloy atomized by the low-pressure inert gas is 1-2:

1.

7. The method for preparing a high-strength and ductile mixed crystal copper alloy according to claim 1, characterized in that: Alumina powder is added to the molten copper alloy which is atomized using high pressure inert gas.

8. The method for preparing a high-strength and ductile mixed crystal copper alloy according to claim 1, characterized in that: In step 5, for preparing the mixed crystal copper-nickel-silicon alloy, the post-treatment includes hot rolling, solution treatment, cold rolling, and aging treatment in sequence.

9. The method for preparing a high-strength and ductile mixed crystal copper alloy according to claim 1, characterized in that: In step 5, for preparing the mixed crystal copper-zinc-manganese-silicon-nickel alloy, the post-treatment includes homogenization, hot rolling, and cold rolling treatment in sequence.

10. The method for preparing a high-strength and ductile mixed crystal copper alloy according to claim 1, characterized in that: In step 5, for preparing the mixed crystal copper-chromium-zirconium alloy, the post-treatment includes hot rolling, solution treatment, and aging treatment in sequence.

Images