A high-strength and high-conductivity in-situ particle-reinforced copper-based composite material and preparation method thereof

Abstract

The present invention discloses a high-strength and high-conductivity in-situ particle-reinforced copper-based composite material and a preparation method thereof. In the copper-based composite material, the total content of Al2O3 particles, TiO2 particles and REAlO3 particles is less than or equal to 2 wt%, and the balance is copper; the content of TiO2 particles is 0.5-0.7 wt%; the content of Al2O3 particles is 0.6-0.8 wt%; the REAlO3 particles are CeAlO3 particles or LaAlO3 particles. Preparation method: Mix copper powder, aluminum powder, titanium powder, copper oxide powder and rare earth oxide powder and press them into a preform; melt pure copper to obtain a pure copper melt; add the preform to the pure copper melt for contact reaction, and stir evenly after the reaction to obtain a mixed melt; use the near-melting-point casting method to cast the mixed melt to obtain a copper-based composite material ingot; perform two-stage alternating treatment of rolling and annealing on the copper-based composite material ingot. The present invention can solve the problem that the mechanical properties and electrical conductivity of the existing copper-based composite materials cannot be both achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of copper-based composite materials, in particular to a high-strength and high-conductivity in-situ particle-reinforced copper-based composite material and a preparation method thereof. Background Art

[0002] Copper-based composite materials have good electrical conductivity, thermal conductivity, high strength and good plasticity, and are widely used in high-end fields such as overhead wires for high-speed rail transit, electronic countermeasures for national defense and military industry, radar, and high-power military microwave tubes. With the rapid development of my country's electronics industry and high-speed railways, higher requirements are placed on the performance of copper-based composite materials. In engineering, it is hoped that isotropy, tensile strength exceeding 600MPa, and relative conductivity greater than 80% ICSA can be obtained to meet the large-scale production of copper-based composite materials. The 0.94Al2O3·0.16Zr / Cu composite material developed by CHEMET in the United States has a tensile strength of 538MPa, a yield strength of 462MPa, and a conductivity of 76% IACS. At present, there is still little industrial production of in-situ particle-reinforced copper-based composite materials in China. Summary of the invention

[0003] To this end, the technical problem to be solved by the present invention is to provide a high-strength and high-conductivity in-situ particle-reinforced copper-based composite material and a preparation method thereof, so as to solve the problem that the existing copper-based composite materials cannot have both mechanical properties and conductive properties.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] A high-strength and high-conductivity in-situ particle-reinforced copper-based composite material, wherein the total content of Al2O3 particles, TiO2 particles and REAlO3 particles is less than or equal to 2wt%, and the balance is copper; the content of TiO2 particles is 0.5-0.7wt%; the content of Al2O3 particles is 0.6-0.8wt%; and the REAlO3 particles are CeAlO3 particles or LaAlO3 particles. If the content of Al2O3 particles, TiO2 particles and LaAlO3 / CeAlO3 particles is too low, the copper-based composite material cannot be well strengthened, the grain area is not fine enough, the dislocation density is low, and the tensile strength of the final composite material is low; if the content of Al2O3 particles, TiO2 particles and LaAlO3 / CeAlO3 particles is too high, the phenomenon of particle agglomeration will occur in the composite material, the scattering of free electrons when passing through will increase, and the relative conductivity will be greatly affected; in addition, microcracks will form at the in-situ particle agglomeration point during the stretching process of the composite material, resulting in fracture, which affects the mechanical properties of the composite material.

[0006] The method for preparing the above-mentioned high-strength and high-conductivity in-situ particle-reinforced copper-based composite material comprises the following steps:

[0007] Step (1), copper powder, aluminum powder, titanium powder, copper oxide powder and rare earth oxide powder are mixed, ground and pressed into a prefabricated block; the rare earth oxide powder is lanthanum oxide or cerium oxide powder;

[0008] Step (2), smelting pure copper in a non-vacuum environment to obtain a pure copper melt;

[0009] Step (3), adding the prefabricated block into the pure copper melt for contact reaction, and stirring evenly after the reaction is completed to obtain a mixed melt;

[0010] Step (4), casting the mixed melt by a near-melting-point casting method to obtain a copper-based composite material ingot;

[0011] Step (5), subjecting the copper-based composite material ingot to two-stage alternating rolling and annealing treatment to obtain a high-strength and high-conductivity in-situ particle-reinforced copper-based composite material.

[0012] Al2O3, TiO2 and LaAlO3 / CeAlO3 particles are all hard ceramic particles that can be generated in situ in pure copper melt through chemical reactions. Therefore, they have a good interface structure with the matrix, have a weak barrier effect on free electrons, and have little effect on electrical properties. In addition, in the nucleation process, a specific content of in-situ particles can act as non-uniform nucleation particles, increase the nucleation rate, and play a role in refining grains, thereby improving the tensile strength of the composite material. At the same time, when the composite material is rolled, these in-situ particles will produce a dislocation pinning effect on the composite material, which can greatly increase the tensile strength of the composite material while slightly reducing its electrical conductivity.

[0013] The method for preparing the high-strength and high-conductivity in-situ particle-reinforced copper-based composite material is as follows: in step (1), the content of copper powder in the prefabricated block is 45-50wt%; the molar ratio of aluminum powder, titanium powder and copper oxide powder is 2:1:5; the amount of rare earth oxide powder used is 0.2-0.3wt% of the total mass of the copper-based composite material. Since the Al-Ti-CuO system releases a large amount of heat during the reaction, the melt is very likely to splash, so copper powder must be added as a diluent to ensure safety, and copper powder as a diluent will not generate other impurity phases; when the content of the diluent copper powder in the prefabricated block is too little, the melt will splash and cause the loss of the in-situ generated particles, so that the in-situ particle content is lower than the design value, but if the amount of the diluent copper powder is too much, the reaction process will be too slow, which may not only cause an incomplete reaction, but also affect the dispersion effect of the in-situ particles in the matrix. When preparing the prefabricated blocks, the amounts of aluminum powder, titanium powder, copper oxide powder and rare earth oxide powder are calculated based on the designed values ​​of the contents of the three particles, Al2O3 particles, TiO2 particles and REAlO3 particles, and the following chemical reaction equation for the in-situ reaction: 4Al+Ti+8CuO+RE2O3=Al2O3+TiO2+2REAlO3+8Cu.

[0014] In the method for preparing the high-strength and high-conductivity in-situ particle-reinforced copper-based composite material, in step (1), the copper powder, aluminum powder, titanium powder, copper oxide powder and rare earth oxide powder are all sieved through a 500-mesh sieve; and the mixing and grinding time is 0.5 to 1.5 hours.

[0015] In the method for preparing the high-strength and high-conductivity in-situ particle-reinforced copper-based composite material, in step (1), when pressing into a prefabricated block, the molding pressure is 10-12 MPa and the pressure holding time is 1-3 minutes.

[0016] In the preparation method of the above-mentioned high-strength and high-conductivity in-situ particle-reinforced copper-based composite material, in step (2), when pure copper is smelted, the pure copper is added into a graphite crucible and heated to 1100-1200° C. with the furnace, and kept warm until the pure copper is completely melted to obtain a pure copper melt.

[0017] In the method for preparing the high-strength and high-conductivity in-situ particle-reinforced copper-based composite material, in step (3), the temperature of the pure copper melt is first raised to 1250-1300° C. and then the prefabricated block is added, and the reaction temperature is maintained at 1250-1300° C. during the contact reaction; the contact reaction takes Al-Ti-CuO-Ce2O3 as a reaction system as an example, pure copper is used as a matrix, and the reaction system undergoes the following reaction in the pure copper melt:

[0018] Ti+2CuO=TiO2+2Cu; 2Al+3CuO=Al2O3+3Cu; Ce2O3+Al2O3=2CeAlO3;

[0019] The entire reaction process is completed within a few seconds, after which a quartz rod is used to stir the mixture so that the in-situ particles are evenly distributed in the copper matrix. When the melt temperature drops to a level close to the melting point of pure copper, casting (near-melting-point casting) is performed. The mass of reactants required to generate these in-situ particles is calculated based on the relative molecular mass.

[0020] In the method for preparing the high-strength and high-conductivity in-situ particle-reinforced copper-based composite material, in step (4), the temperature of the mixed melt is lowered to 1080-1110° C. before casting, and the mold is preheated to 180-210° C. before casting.

[0021] In the preparation method of the above-mentioned high-strength and high-conductivity in-situ particle-reinforced copper-based composite material, in step (5), the process of the two-stage alternating rolling and annealing is as follows: first, the copper-based composite material ingot is subjected to a room temperature rolling at room temperature, with a deformation of 80-90%; then, the billet after the first rolling is subjected to a primary annealing treatment at 220°C for 15 minutes; then, the billet is subjected to a second room temperature rolling at room temperature, with a deformation of 60-70%; and finally, the billet is subjected to a secondary annealing treatment at 190°C.

[0022] The preparation method of the high-strength and high-conductivity in-situ particle-reinforced copper-based composite material, in step (1), the content of copper powder in the prefabricated block is 45wt%; the molar ratio of aluminum powder, titanium powder and copper oxide powder is 2:1:5; the rare earth oxide powder is cerium oxide, and the amount of cerium oxide used is 0.3wt% of the total mass of the copper-based composite material; the copper powder, aluminum powder, titanium powder, copper oxide powder and cerium oxide powder are all sieved with a 500-mesh sieve (if the powder particle size is too large, the in-situ particle size generated by the contact reaction will be too large, which will not be ideal for improving the performance of the composite material); the mixing and grinding time is 1h (the grinding time is too short The reactant powders are unevenly mixed, resulting in incomplete contact reaction, and the mass fraction of in-situ particles in the prepared composite material is lower than the theoretical design value; if the grinding time is too long, the powder particle size is too small, which will cause the in-situ particles to agglomerate, affecting the performance of the composite material); when pressed into a prefabricated block, the molding pressure is 12MPa and the holding time is 3min (the molding pressure and holding time will affect the compactness of the prefabricated block, thereby affecting the effect of the in-situ reaction. Under the molding conditions of the present invention, the compactness is moderate, and under the process conditions of the present invention, a relatively ideal in-situ reaction effect can be obtained);

[0023] In step (2), when pure copper is smelted, pure copper is added into a graphite crucible and heated to 1200° C. with the furnace, and kept warm until the pure copper is completely melted to obtain a pure copper melt;

[0024] In step (3), the temperature of the pure copper melt is first raised to 1300° C. and then the prefabricated block is added, and the reaction temperature is maintained at 1300° C. during the contact reaction; if the contact reaction temperature is too low, the contact reaction will not be thorough, so that the mass fraction of the in-situ particles in the final composite material is lower than the theoretical design value; if the contact reaction temperature is too high, the reaction is more violent and splashing is likely to occur, and the in-situ particles are ejected with the melt, and the mass fraction of the in-situ particles in the composite material is still lower than the theoretical design value;

[0025] In step (4), the temperature of the mixed melt is lowered to 1100° C. before casting, and the mold is preheated to 200° C. before casting;

[0026] In step (5), the two-stage alternating treatment process of rolling and annealing is as follows: first, the copper-based composite material ingot is subjected to a room temperature rolling at room temperature, and the deformation is 85% (when the deformation of the first rolling is too low, the mechanical properties of the composite material cannot be effectively improved, but if the deformation is too high, the relative conductivity will be affected); then, the blank after the first rolling is subjected to a first-stage annealing treatment at 220° C. for 15 min (when the first-stage annealing temperature is lower than 220° C., the relative conductivity of the composite material cannot be restored to above 80% IACS, and the expected target cannot be achieved; if the annealing temperature is higher than 220° C., the mechanical properties of the composite material will be greatly lost; in addition, if the annealing time is longer than 15 min, the grains will grow, affecting the mechanical properties of the composite material; but if the annealing time is shorter than 15 min, the relative conductivity of the composite material will be reduced. The rate is difficult to recover to above 80% IACS); then the billet is subjected to secondary room temperature rolling at room temperature with a deformation of 65% (if the secondary rolling deformation is too low, the effect of improving the mechanical properties of the composite material is not obvious; but if the deformation is too high, it will affect the electrical properties of the composite material); finally, the billet is subjected to secondary annealing at 190°C for 15min (if the secondary annealing temperature is lower than 190°C, the relative conductivity of the composite material cannot be recovered to above 80% IACS; if the secondary annealing temperature is higher than 190°C, the mechanical properties of the composite material will be greatly lost and the expected target cannot be achieved; when the secondary annealing time is longer than 15min, the grain size is too large, resulting in a decrease in the mechanical properties of the composite material; if the annealing time is shorter than 15min, the electrical properties of the composite material cannot be recovered to above 80% IACS).

[0027] The technical solution of the present invention achieves the following beneficial technical effects:

[0028] 1. The present invention adopts non-vacuum contact reaction + near melting point casting method to prepare Al2O3·TiO2·CeAlO3 / Cu copper-based composite ingot, and then processes through primary rolling + primary annealing + secondary rolling + secondary annealing to obtain copper-based composite material, whose tensile strength exceeds 600MPa and relative conductivity is greater than 80% ICSA, achieving the structural and functional integration performance index of high-strength and high-conductivity copper-based composite material, which can meet the industry's performance requirements for high-strength and high-conductivity copper-based composite materials and meet the needs of high-performance cutting-edge technology. At the same time, the preparation and processing process is carried out in a non-vacuum environment, with no special requirements for equipment, which is conducive to the industrial large-scale production of high-strength and high-conductivity copper-based composite materials.

[0029] 2. The present invention generates Al2O3, TiO2, and CeAlO3 particles in situ in pure copper, and the interface between the dispersion strengthening phase and the copper matrix is ​​clean and pollution-free, and no interface reaction occurs. In the subsequent near-melting point casting process, nucleation is promoted to hinder grain growth, effectively refine the grains, and obtain a fine-grain strengthening effect.

[0030] 3. The copper-based composite material prepared by the method of the present invention is a pure copper-based composite material synergistically reinforced by a variety of in-situ particles. While ensuring the high conductivity of the material, its strength is also maintained at a high level, which is due to the organic combination of material design and process design. The number and size of the reinforcing phase have certain designability, and pure copper is selected as the matrix to avoid the serious scattering phenomenon of free electrons caused by solid solution strengthening. The contact reaction in the preparation method ensures the in-situ synthesis of the reinforcing phase and its better distribution state. Under the action of the in-situ particles, near-melting point casting can ensure the uniformity of the grain structure. The alternating processing process of rolling and annealing process of the present invention can ensure the formation of nano twins (deformation twins and annealing twins) inside the material, overcome the "inverted" relationship between strength and conductivity, and achieve the premise of maintaining good conductivity while improving strength, meeting the actual use requirements.

[0031] 4. The present invention uses 0.63TiO2·0.8Al2O 3 / Rare earth oxides La2O3 or Ce2O3 are introduced into the reaction system (Al-Ti-CuO) of the Cu composite material to form an Al-Ti-CuO-La2O3 or Al-Ti-CuO-Ce2O3 reaction system. La2O3 or Ce2O3 can participate in the reaction to generate new in-situ particles LaAlO3 or CeAlO3. Among them, the LaAlO3 particles are long elliptical, with a size of about 1μm, and have a semi-coherent interface relationship with the Cu matrix; the CeAlO3 particles are spherical, with a size of about 1μm, and have a coherent interface relationship with the Cu matrix. After adding rare earth oxides, the size of TiO2 particles is refined from 0.5-1μm to about 50nm. At this time, the composite material is synergistically strengthened by TiO2, Al2O3, and LaAlO3 (CeAlO3). The tensile strength of the TiO2·Al2O3·LaAlO3 / Cu composite material is 549MPa, and the relative conductivity is 81.2%IACS; the tensile strength of the TiO2·Al2O3·CeAlO3 / Cu composite material is 613MPa, and the relative conductivity is 81.6%IACS. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 XRD test result diagram of the copper-based composite material prepared in Example 1 of the present invention;

[0033] Figure 2a The cast microstructure diagram of the copper-based composite material prepared in Example 1 of the present invention;

[0034] Figure 2b Microstructure diagram of the copper-based composite material in secondary rolling state prepared in Example 1 of the present invention;

[0035] Figure 3a Distribution diagram of in-situ particles of the copper-based composite material prepared in Example 1 of the present invention (low magnification);

[0036] Figure 3b Distribution diagram of in-situ particles of the copper-based composite material prepared in Example 1 of the present invention (high magnification);

[0037] Figure 4a Microscopic morphology of in-situ TiO2 particles in the copper-based composite material prepared in Example 1 of the present invention under a transmission electron microscope;

[0038] Figure 4b The electron diffraction pattern of the in-situ TiO2 particles in the copper-based composite material prepared in Example 1 of the present invention;

[0039] Figure 5a Microscopic morphology of in-situ CeAlO3 particles in the copper-based composite material prepared in Example 1 of the present invention under a transmission electron microscope;

[0040] Figure 5b Electron diffraction pattern of in-situ CeAlO3 particles in the copper-based composite material prepared in Example 1 of the present invention;

[0041] Figure 6 Microscopic morphology of nano twins of the copper-based composite material prepared in Example 1 of the present invention after secondary rolling;

[0042] Figure 7 A curve diagram showing the change in relative conductivity of the copper-based composite material prepared in Example 1 of the present invention under different conditions;

[0043] Figure 8 Stress-strain curve of the copper-based composite material prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0044] Example 1

[0045] The preparation method of the high-strength and high-conductivity in-situ particle-reinforced copper-based composite material of this embodiment comprises the following steps:

[0046] Step (1), copper powder, aluminum powder, titanium powder, copper oxide powder and cerium oxide powder are mixed and ground and then pressed into a prefabricated block; the content of copper powder in the prefabricated block is 45wt%; the molar ratio of aluminum powder, titanium powder and copper oxide powder is 2:1:5, and the specific amounts of aluminum powder, titanium powder and copper oxide powder are calculated according to the content of TiO2 particles in the prepared copper-based composite material being 0.63wt% and the content of Al2O3 particles being 0.8wt%; the amount of cerium oxide is 0.3wt% of the total mass of the copper-based composite material; aluminum powder, titanium powder, copper oxide powder and cerium oxide powder are all sieved through a 500-mesh sieve; the mixing and grinding time is 1h; when pressed into the prefabricated block, the molding pressure is 12MPa and the pressure holding time is 3min;

[0047] Step (2), using a medium frequency electromagnetic induction melting furnace to melt pure copper in a non-vacuum environment to obtain a pure copper melt; when melting pure copper, adding pure copper into a graphite crucible and heating it to 1200° C. with the furnace, and keeping the temperature until the pure copper is completely melted to obtain a pure copper melt;

[0048] Step (3), adding the prefabricated block to the pure copper melt for contact reaction, stirring evenly after the reaction is completed to obtain a mixed melt; firstly raising the temperature of the pure copper melt to 1300°C and then adding the prefabricated block, and maintaining the reaction temperature at 1300°C during the contact reaction; the contact reaction uses Al-Ti-CuO-Ce2O3 as the reaction system and pure copper as the matrix, and the reaction system undergoes the following reaction in the pure copper melt:

[0049] 4Al+Ti+8CuO+Ce2O3=Al2O3+TiO2+2CeAlO3+8Cu, the mass of the reaction substances required to generate these in-situ particles is calculated according to the equation and the content of each in-situ particle in the melt; the whole reaction process is completed within a few seconds, after which a quartz rod is used to stir so that the in-situ particles are evenly distributed in the copper matrix;

[0050] Step (4), using a near-melting-point casting method to cast the mixed melt to obtain a copper-based composite material ingot; casting is performed when the temperature of the mixed melt is reduced to 1100° C., and the mold is preheated to 200° C. before casting;

[0051] Step (5), subjecting the copper-based composite material ingot to two-stage alternating rolling and annealing treatment to obtain a high-strength and high-conductivity in-situ particle-reinforced copper-based composite material; the process of the two-stage alternating rolling and annealing treatment is as follows: first, the copper-based composite material ingot is subjected to a room temperature rolling once, with a deformation of 85%; then, the billet after the first rolling is subjected to a primary annealing treatment at a temperature of 220° C. for 15 minutes; then, the billet is subjected to a second room temperature rolling at room temperature, with a deformation of 65%; and finally, the billet is subjected to a secondary annealing treatment at a temperature of 190° C. for 15 minutes.

[0052] like Figure 1 As shown, Al2O3 particles, TiO2 particles and CeAlO3 particles are in-situ generated in the copper-based composite material prepared in this embodiment; the copper-based composite material is synergistically strengthened by TiO2, CeAlO3 and Al2O3 that does not participate in the reaction. Figure 2a and Figure 2b It can be seen that the grains of the copper-based composite material are all uniform equiaxed crystals, there are no columnar crystals, and the grain boundaries are also very clean. Figure 3a and Figure 3b It can be seen that the particle size is about 1μm, spherical, and dispersed in the matrix without agglomeration. Figure 4a and Figure 4bThe TiO2 particles are still nearly spherical, with a size of about 50nm, which is significantly finer than the TiO2 particles (0.5-1μm) generated by the reaction system without adding cerium oxide, and the interface relationship between the TiO2 particles and the matrix is ​​good; this is because Ce2O3 has high surface activity and low surface tension. Adding it to the melt can reduce the interfacial energy of the melt. The reduction in interfacial energy reduces the critical nucleation free energy of the TiO2 particles, making it easier for the TiO2 particles to nucleate. Figure 5a and Figure 5b It can be determined that the in-situ generated CeAlO3 particles are spherical, about 1 μm in size, and have a coherent interface relationship with the copper matrix, indicating that the bonding strength with the matrix is ​​high. When the composite material is stretched, the load can be transferred to these in-situ particles, enabling them to withstand higher loads, which is manifested as an increase in tensile strength on a macro scale. Figure 6 It shows that the twin length of the copper-based composite material is about 1 μm and the width is about 20 nm.

[0053] from Figure 7 and Figure 8 It can be seen that the high-strength and high-conductivity in-situ particle-reinforced copper-based composite material TiO2·Al2O3·CeAlO3 / Cu prepared in this embodiment has good comprehensive properties, with a room temperature tensile strength of 613MPa and a room temperature conductivity of 81.6%IACS. The in-situ particle-reinforced copper-based composite material prepared by the preparation method of this embodiment solves the contradictory relationship between high conductivity and high strength of copper materials, and achieves a better match between mechanical properties and electrical properties.

[0054] Example 2.

[0055] The only difference between this embodiment and embodiment 1 is that in step (1), lanthanum oxide powder is used instead of cerium oxide powder, and the amount of lanthanum oxide used is 0.2 wt% of the total mass of the copper-based composite material; the other steps and parameter conditions are the same as those in embodiment 1.

[0056] Compared with Example 1, the in-situ generated LaAlO3 particles of the copper-based composite material TiO2·Al2O3·LaAlO3 / Cu prepared in this embodiment are long and oval, with a size of about 1 μm, and have a semi-coherent interface relationship with the Cu matrix; its microstructure is similar to that of the copper-based composite material of Example 1, and it will not be characterized here. The tensile strength of the TiO2·Al2O3·LaAlO3 / Cu copper-based composite material prepared in this embodiment is 549MPa, and the relative conductivity is 81.2%IACS, and the comprehensive performance is not as good as that prepared in Example 1.

[0057] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A method for preparing a high-strength and high-conductivity in-situ particle-reinforced copper-based composite material, characterized in that: The steps include: Step (1), copper powder, aluminum powder, titanium powder, copper oxide powder and rare earth oxide powder are mixed, ground and pressed into a prefabricated block; the rare earth oxide powder is lanthanum oxide or cerium oxide powder; the content of copper powder in the prefabricated block is 45-50wt%; the molar ratio of aluminum powder, titanium powder and copper oxide powder is 2:1:5; the amount of rare earth oxide powder used is 0.2-0.3wt% of the total mass of the copper-based composite material; Step (2), smelting pure copper in a non-vacuum environment to obtain a pure copper melt; Step (3), adding the prefabricated block into the pure copper melt for contact reaction, and stirring evenly after the reaction is completed to obtain a mixed melt; Step (4), casting the mixed melt by a near-melting-point casting method to obtain a copper-based composite material ingot; Step (5), subjecting the copper-based composite material ingot to two-stage alternating rolling and annealing treatment to obtain a high-strength and high-conductivity in-situ particle-reinforced copper-based composite material; the process of the two-stage alternating rolling and annealing treatment is as follows: first, subjecting the copper-based composite material ingot to one-stage room temperature rolling at room temperature, with a deformation of 80-90%; then, subjecting the blank after the one-stage rolling to one-stage annealing treatment at 220° C. for 15 minutes; then, subjecting the blank to two-stage room temperature rolling at room temperature, with a deformation of 60-70%; and finally, subjecting the blank to two-stage annealing treatment at 190° C.; In the copper-based composite material: the total content of Al2O3 particles, TiO2 particles and REAlO3 particles is less than or equal to 2wt%, and the balance is copper; the content of TiO2 particles is 0.5-0.7wt%; the content of Al2O3 particles is 0.6-0.8wt%; and the REAlO3 particles are CeAlO3 particles or LaAlO3 particles.

2. The method for preparing the high-strength and high-conductivity in-situ particle-reinforced copper-based composite material according to claim 1, characterized in that: In step (1), the copper powder, aluminum powder, titanium powder, copper oxide powder and rare earth oxide powder are all sieved through a 500-mesh sieve; and the mixing and grinding time is 0.5 to 1.5 hours.

3. The method for preparing the high-strength and high-conductivity in-situ particle-reinforced copper-based composite material according to claim 1, characterized in that: In step (1), when pressing into prefabricated blocks, the molding pressure is 10-12 MPa and the pressure holding time is 1-3 min.

4. The method for preparing the high-strength and high-conductivity in-situ particle-reinforced copper-based composite material according to claim 1, characterized in that: In step (2), when pure copper is smelted, pure copper is added into a graphite crucible and heated to 1100-1200° C. with the furnace, and kept warm until the pure copper is completely melted to obtain a pure copper melt.

5. The method for preparing the high-strength and high-conductivity in-situ particle-reinforced copper-based composite material according to claim 1, characterized in that: In step (3), the temperature of the pure copper melt is first raised to 1250-1300° C. and then the prefabricated block is added, and the reaction temperature is maintained at 1250-1300° C. during the contact reaction.

6. The method for preparing the high-strength and high-conductivity in-situ particle-reinforced copper-based composite material according to claim 1, characterized in that: In step (4), casting is performed when the temperature of the mixed melt is reduced to 1080-1110°C, and the mold is preheated to 180-210°C before casting.

7. The method for preparing the high-strength and high-conductivity in-situ particle-reinforced copper-based composite material according to claim 1, characterized in that: In step (1), the content of copper powder in the prefabricated block is 45wt%; the molar ratio of aluminum powder, titanium powder and copper oxide powder is 2:1:5; the rare earth oxide powder is cerium oxide, and the amount of cerium oxide used is 0.3wt% of the total mass of the copper-based composite material; the copper powder, aluminum powder, titanium powder, copper oxide powder and cerium oxide powder are all sieved with a 500-mesh sieve; the mixing and grinding time is 1h; when pressed into a prefabricated block, the molding pressure is 12MPa and the pressure holding time is 3min; In step (2), when pure copper is smelted, pure copper is added into a graphite crucible and heated to 1200° C. with the furnace, and kept warm until the pure copper is completely melted to obtain a pure copper melt; In step (3), the temperature of the pure copper melt is first raised to 1300° C. and then the prefabricated block is added, and the reaction temperature is maintained at 1300° C. during the contact reaction; In step (4), the temperature of the mixed melt is lowered to 1100° C. before casting, and the mold is preheated to 200° C. before casting; In step (5), the two-stage alternating treatment process of rolling and annealing is as follows: first, the copper-based composite material ingot is subjected to room temperature rolling once at room temperature with a deformation of 85%; then, the billet after the first rolling is subjected to a primary annealing treatment at 220°C for 15 minutes; then, the billet is subjected to a second room temperature rolling at room temperature with a deformation of 65%; finally, the billet is subjected to a secondary annealing treatment at 190°C for 15 minutes.

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