High-strength high-conductivity self-lubricating dispersion strengthened copper composite material and preparation method thereof

Abstract

This invention provides a high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material and its preparation method, relating to the technical field of copper composite powder metallurgy. The phase composition of the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material is: 2-10 wt% W dispersion-reinforcing particles, 1-10 wt% MnS self-lubricating particles, and the remainder being a pure copper matrix; wherein the size of the W dispersion-reinforcing particles is 5-100 nm, and the size of the MnS self-lubricating particles is 0.5-5 μm, uniformly distributed within the copper matrix. The preparation method includes sequentially performing micron-sized Cu-Mn alloy powder preparation, copper-based composite powder preparation, pressing, sintering, and hot deformation. This invention's method is simple and easy to operate, possessing unique advantages in preparing self-lubricating, dispersion-reinforced copper composite materials. The resulting composite material exhibits excellent microstructure and properties, the sintering and extrusion processes are completed continuously, the manufacturing process is short, and the production cost is low, enabling large-scale industrial production.

Description

Technical Field

[0001] This invention relates to the technical field of copper composite powder metallurgy, and in particular to a high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material and its preparation method. Background Technology

[0002] Dispersion strengthening is a method of strengthening metals by adding or forming stable, matrix-independent second-phase particles. Nano-alumina dispersion-strengthened copper significantly improves the strength, hardness, and softening temperature of copper while retaining high electrical conductivity close to that of copper itself. It is a preferred material for resolving the contradiction between strength and conductivity, and is widely used in high-tech fields requiring both high strength and high conductivity, such as high-speed rail contact wires, resistance welding electrodes, conductive nozzles, and linear propulsion components for electromagnetic energy equipment. However, these fields face extreme environments of current-carrying friction and wear during service, and the friction and wear resistance of dispersion-strengthened copper currently needs improvement.

[0003] Currently, methods to improve the tribological properties of copper alloys mainly include adding soft metals (such as Pb and Sn) and solid lubricants (such as graphite and sulfides). Soft metal elements such as Pb and Sn dissolve into the copper matrix, causing lattice distortion and strongly increasing electron scattering, leading to a significant decrease in the conductivity of the copper alloy, failing to meet application requirements. Adding solid lubricants such as graphite and sulfides to copper alloys can reduce the coefficient of friction between the copper alloy and the mating couple, reducing wear and improving tribological properties; however, the large amount of solid lubricant added weakens the interface between the matrix and the lubricant, significantly reducing the strength, toughness, and conductivity of the copper alloy. In particular, sulfide lubricants such as MoS2 and WS2 decompose at high temperatures, losing their lubricating properties and failing to meet high-temperature service requirements.

[0004] For example, Chinese patent CN107488793A discloses a high-conductivity dispersed copper-based high-temperature self-lubricating composite material and its preparation method. The composite material is designed to include oxygen-free copper powder, alumina dispersed copper powder, molybdenum disulfide powder, and graphite, which are mixed and then hot-pressed and sintered. Obviously, the alumina dispersed copper powder requires special preparation, which is costly and inefficient. Moreover, the alumina content in the alumina dispersed copper powder is low, and its effect on improving mechanical properties is not significant. Although it can improve wear resistance to a certain extent, the improvement in mechanical properties is not significant. The same applies to molybdenum disulfide powder and graphite. In addition, the electrical conductivity is low.

[0005] Chinese patent CN102994799A discloses a copper-based self-lubricating composite material and its preparation method. It requires the addition of 2-4% yttrium barium copper oxide to copper-based materials to synergistically improve conductivity, thermal stability, and friction reduction and wear resistance. However, yttrium barium copper oxide can only play this role when it is of high purity. High-purity yttrium barium copper oxide is very expensive. For example, the Aladdin brand certified product, with a 10-gram package, a purity of 99.9%, and a particle size ≤5μm, is priced at approximately RMB 1516.90.

[0006] Chinese patent CN101956094A discloses a high-strength, high-conductivity dispersion-strengthened copper alloy and its preparation method. This method requires adding a ceramic dispersion-strengthening phase and doping elements to the copper-based metal. Although it can solve the problems of ceramic particle agglomeration caused by poor interfacial bonding between copper and ceramic, coarsening of ceramic particles during sintering, and decreased conductivity of the material caused by electron scattering at the copper-ceramic interface, the strengthening phase particles in the dispersion-strengthened copper alloy prepared by this method are nanoscale in size and have a very low content, making it difficult to improve the alloy's anti-friction and wear performance. In order to improve conductivity, high-cost doping elements need to be added.

[0007] Chinese patent CN101121974A discloses a high-strength, high-conductivity dispersion-strengthened copper alloy and its preparation method. The preparation process is not only complex, but the added aluminum content is also not high, not exceeding 1%. It also requires the preparation of alloy thin plates and internal oxidation, and finally the stacking, hot pressing and hot extrusion, and processing to obtain the desired product. Therefore, the thickness of the product is 0.3-2.0 mm, and the improvement in hardness and conductivity is only average, while the tensile strength is not effectively improved. Summary of the Invention

[0008] To address the limitations of existing technologies that fail to synergistically improve the thermal and electrical conductivity, mechanical properties, and tribological properties of copper alloys, and the fact that adding dispersion-strengthened metal oxides or dopants only improves one aspect of performance, while also incurring drawbacks such as high cost of dopants, the need for subsequent hot deformation processing with ceramic dispersion-strengthened phases and dopants, and the requirement for specialized preparation of dispersion-strengthened metal oxides, this invention proposes a high-strength, high-conductivity, self-lubricating dispersion-strengthened copper composite material and its preparation method. The technical solution is as follows:

[0009] A high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material is disclosed. The composite material is in the form of rods, plates, tubes, or complex-shaped parts. The phase composition is: 2-10 wt% W dispersion-reinforcing particles, 1-10 wt% MnS self-lubricating particles, and the remainder is pure copper matrix. The W dispersion-reinforcing particles have a size of 5-100 nm, and the MnS self-lubricating particles have a size of 0.5-5 μm, and are uniformly distributed in the copper matrix.

[0010] Optionally, in the phase composition of the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material, the W dispersion-reinforced particles are spherical or ellipsoidal in shape, and the MnS self-lubricating particles are nearly spherical, polygonal, or irregular in shape.

[0011] Optionally, the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material has a hardness of HRB70-95, a thermal conductivity of 310-360 W / (m·K), a tensile strength of 500-650 MPa, a yield strength of 430-610 MPa, a fracture elongation of 8-25%, and an electrical conductivity of 80-90% IACS; using 7075 aluminum alloy as the friction pair, the coefficient of friction is reduced by 30-80% compared to traditional alumina dispersion-reinforced copper.

[0012] A method for preparing the above-mentioned high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material, comprising the following steps:

[0013] S1. Preparation of micron-sized Cu-Mn alloy powder: Electrolytic copper plate and electrolytic manganese ingot are melted into alloy liquid under vacuum and then atomized to obtain micron-sized Cu-Mn alloy powder.

[0014] S2, Preparation of copper-based composite powder: S1 micron-sized Cu-Mn alloy powder and WS2 powder were mixed, and then mechanical alloying was achieved by high-energy ball milling to obtain copper-based composite powder;

[0015] S3, copper composite material green compact pressing: S2 copper-based composite powder is loaded into a mold and pressed to obtain copper composite material green compact;

[0016] S4. Preparation of copper-based composite sintered billet: The S3 copper composite green billet is sintered in a hydrogen atmosphere to obtain a copper-based composite sintered billet.

[0017] S5. Preparation of copper-based composite material by hot deformation: After the sintering of S4 copper-based composite material ingot is completed, it is directly hot extruded without cooling to obtain fully densified copper-based composite material profile.

[0018] Optionally, the superheating temperature of the alloy melt in S1 is 100-250℃; the high-pressure atomizing medium can be one or more of nitrogen, argon or water, and the atomizing pressure is 2-25MPa; the average particle size of the micron-sized Cu-Mn alloy powder is 74-200μm, of which the Mn content is 0.7-7wt%, and the remainder is pure copper.

[0019] Optionally, the high-energy ball milling method in S2 can be planetary ball milling, stirred ball milling, or vibratory ball milling. The grinding ball material is one or more of alumina, zirconium oxide, and agate. The ball-to-material ratio is 5:1-30:1. The ball milling control agent is one or more of acetone, n-hexane, and dichloromethane. The rotation speed of the planetary ball milling and stirred ball milling is 100-400 rpm, the frequency of the vibratory ball milling is 30-400 Hz, the ball milling time is 12-48 h, the average particle size of the WS2 powder is 0.1-10 μm, and the content is 3-14 wt%; the average particle size of the copper-based composite powder is 80-400 μm.

[0020] Optionally, the mold material in S3 is rubber, silicone sleeve or metal; the pressing forming is molding and cold isostatic pressing, the pressing pressure is 100-500MPa, and the holding time is 30-300s; copper composite material blanks are used to make complex shaped parts, bar blanks, tube blanks, plate blanks and irregular blanks.

[0021] Optionally, the sintering temperature in S4 is 700-900℃, the heating rate is 2-20℃ / min, and the holding time is 1-5h; the relative density of the copper-based composite sintered billet is 95-99%, the hardness is HRB35-55, the thermal conductivity is 240-320W / (m·K), the tensile strength is 180-300MPa, the yield strength is 120-220MPa, the elongation at break is 5-20%, and the electrical conductivity is 70-90%IACS; using 7075 aluminum alloy as the friction pair, the coefficient of friction is reduced by 30-50% compared to traditional alumina dispersion-strengthened copper.

[0022] Optionally, the hot deformation in S5 can be hot extrusion, hot drawing, or other hot deformation processes.

[0023] Optionally, when hot deformation in S5 is hot extrusion, the extrusion ratio is 10:1-80:1; after hot extrusion, the composite material rods or strips are obtained by drawing or cold rolling according to actual use requirements.

[0024] Technical principle of the invention:

[0025] This invention introduces Mn into a copper matrix using an atomization powdering method to obtain Cu-Mn alloy powder. The Cu-Mn alloy powder is then mixed with WS2 powder and mechanically alloyed through high-energy ball milling. W and S elements are non-equilibrium dissolved in the Cu-Mn alloy powder, reaching a supersaturated state, resulting in a copper-based composite powder. This powder is then processed through forming, phase transformation sintering, and hot extrusion to produce a copper-based composite material with both strength and lubrication properties. During the sintering heating process, nano-sized W particles precipitate from the copper-based composite powder, providing dispersion strengthening. Mn and S diffuse and combine to form submicron MnS particles. The soft MnS forms a thin film on the surface of the friction couple during friction, providing self-lubrication. The precipitation of W and the diffusion combination of MnS reduce the lattice distortion energy of the copper matrix; both processes are exothermic. The heat released from these two phase transformations promotes sintering densification. The in-situ formed nano-W particles and submicron MnS particles maintain a good non-coherent interface with the copper matrix, resulting in weak electron scattering. Through dual-phase synergistic strengthening, a dispersion-reinforced copper composite material with high strength, high conductivity, and high wear resistance is obtained.

[0026] This invention introduces two second phases, nano-sized W particles and submicron MnS particles, in situ into a copper matrix. The W particles act as dispersion reinforcement, while the MnS particles provide self-lubrication. The resulting self-lubricating, dispersion-reinforced copper composite material exhibits fine grains and superior comprehensive properties, including high strength, high electrical conductivity, and high wear resistance, surpassing copper-based composite materials prepared using traditional processes.

[0027] This invention requires controlling atomization process parameters such as melt superheat and atomization pressure. This is because if the melt superheat is too high, the melt viscosity decreases, and coupled with excessive atomization pressure, it can easily lead to excessively fine Cu-Mn alloy powder; and excessively fine Cu-Mn alloy powder can easily lead to the following technical defects:

[0028] On the one hand, due to the fine particle size of WS2 powder, the mechanical alloying process with ultrafine Cu-Mn alloy powder is insufficient, resulting in WS2 residue, which will deteriorate the mechanical and electrical properties of the composite material; on the other hand, the poor flowability of ultrafine powder affects the formability of the powder during the pressing process.

[0029] The key technical point of this invention is:

[0030] The above technical solution has at least the following advantages compared with the existing technology:

[0031] The above-mentioned solution proposes a high-strength, high-conductivity, self-lubricating dispersion-reinforced copper composite material, which can solve the technical problems in the prior art, such as the inability to synergistically improve the thermal and electrical conductivity and mechanical properties of copper alloys, the fact that adding dispersion-reinforced metal oxides and doping elements can only improve one aspect of the performance, the high cost of added doping elements, the need for subsequent hot deformation processing after adding ceramic dispersion-reinforced phases and doping elements, and the need for special preparation of dispersion-reinforced metal oxides.

[0032] This invention employs vacuum induction melting to strictly control the melting process, thereby avoiding the oxidation and burn-off of Mn elements and the presence of oxide inclusions in the alloy powder.

[0033] This invention, by selecting the Mn element content, enables the mechanically alloyed copper-based composite powder to generate MnS particles with an appropriate content in situ during the sintering process. This not only provides good self-lubrication and improves friction and wear performance, but also avoids significantly reducing the mechanical properties of the matrix.

[0034] This invention obtains Cu-Mn alloy powder with the required particle size by strictly controlling atomization process parameters such as melt superheat and atomization pressure.

[0035] This invention controls the sintering temperature to prevent the copper grain size from increasing excessively, and also keeps the W particles and MnS particles at the nanometer and submicrometer sizes, respectively. This ensures that the sintered billet, after extrusion, possesses both high strength, high conductivity, and excellent tribological properties, with overall performance improved by more than 50% compared to traditional dispersion-strengthened copper.

[0036] The self-lubricating dispersion-reinforced copper composite material prepared by this invention has fine grains and excellent comprehensive properties such as high strength, high conductivity, and high wear resistance, which are superior to copper-based composite materials prepared by traditional processes.

[0037] The high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material prepared in this invention has a hardness of HRB70-95, a thermal conductivity of 310-360 W / (m·K), a tensile strength of 500-650 MPa, a yield strength of 430-610 MPa, a fracture elongation of 8-25%, and an electrical conductivity of 80-90% IACS. Using 7075 aluminum alloy as the friction pair, the coefficient of friction is reduced by 30-80% compared to traditional alumina dispersion-reinforced copper.

[0038] In summary, compared with traditional chemical methods and other conventional methods such as mixing and external addition, the method of this invention prepares dispersion-reinforced copper composite materials with uniform composition distribution, uniform properties, and synergistic improvement in thermal conductivity, electrical conductivity, mechanical properties, and wear resistance through the preparation of micron-sized Cu-Mn alloy powder, copper-based composite powder, pressing, sintering, and hot deformation. The method is simple and easy to operate, and has unique advantages in the preparation of self-lubricating dispersion-reinforced copper composite materials. The resulting composite material has excellent microstructure and properties, the sintering and extrusion processes are completed continuously, the manufacturing process is short, the production cost is low, and large-scale industrial production can be realized. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a process flow diagram of a high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material according to the present invention;

[0041] Figure 2 This is a microstructure diagram of a high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material according to Embodiment 1 of the present invention;

[0042] Figure 3 This is a microstructure diagram of a high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material according to Embodiment 2 of the present invention;

[0043] Figure 4 This is a microstructure diagram of a high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material according to Embodiment 3 of the present invention;

[0044] Figure 5 This is a microstructure diagram of a high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material according to Embodiment 4 of the present invention. Detailed Implementation

[0045] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0046] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0047] In the embodiments of the present invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that when the distinction is not emphasized, their intended meanings are consistent.

[0048] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0049] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0050] A high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material is disclosed. The composite material is in the form of rods, plates, tubes, or complex-shaped parts. The phase composition is: 2-10 wt% W dispersion-reinforcing particles, 1-10 wt% MnS self-lubricating particles, and the remainder is pure copper matrix. The W dispersion-reinforcing particles have a size of 5-100 nm, and the MnS self-lubricating particles have a size of 0.5-5 μm, and are uniformly distributed in the copper matrix.

[0051] In particular, in the phase composition of the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material, the W dispersion-reinforced particles are spherical or ellipsoidal in shape, and the MnS self-lubricating particles are nearly spherical, polygonal, or irregular in shape.

[0052] Specifically, the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material has a hardness of HRB70-95, a thermal conductivity of 310-360 W / (m·K), a tensile strength of 500-650 MPa, a yield strength of 430-610 MPa, a fracture elongation of 8-25%, and an electrical conductivity of 80-90% IACS. Using 7075 aluminum alloy as the friction pair, the coefficient of friction is reduced by 30-80% compared to traditional alumina dispersion-reinforced copper.

[0053] A method for preparing the above-mentioned high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material, wherein the method for preparing the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material combines... Figure 1 The following steps are required:

[0054] S1. Preparation of micron-sized Cu-Mn alloy powder: Electrolytic copper plate and electrolytic manganese ingot are melted into alloy liquid under vacuum and then atomized to obtain micron-sized Cu-Mn alloy powder.

[0055] S2, Preparation of copper-based composite powder: S1 micron-sized Cu-Mn alloy powder and WS2 powder were mixed, and then mechanical alloying was achieved by high-energy ball milling to obtain copper-based composite powder;

[0056] S3, copper composite material green compact pressing: S2 copper-based composite powder is loaded into a mold and pressed to obtain copper composite material green compact;

[0057] S4. Preparation of copper-based composite sintered billet: The S3 copper composite green billet is sintered in a hydrogen atmosphere to obtain a copper-based composite sintered billet.

[0058] S5. Preparation of copper-based composite material by hot deformation: After the sintering of S4 copper-based composite material ingot is completed, it is directly hot extruded without cooling to obtain fully densified copper-based composite material profile.

[0059] Specifically, the superheating temperature of the alloy melt in S1 is 100-250℃; the high-pressure atomizing medium can be one or more of nitrogen, argon or water, and the atomizing pressure is 2-25MPa; the average particle size of the micron-sized Cu-Mn alloy powder is 74-200μm, of which the Mn content is 0.7-7wt%, and the remainder is pure copper.

[0060] Specifically, the high-energy ball milling method in S2 can be planetary ball milling, stirred ball milling, or vibratory ball milling. The grinding ball material is one or more of alumina, zirconium oxide, and agate. The ball-to-material ratio is 5:1-30:1. The ball milling control agent is one or more of acetone, n-hexane, and dichloromethane. The rotation speed of planetary ball milling and stirred ball milling is 100-400 rpm, the frequency of vibratory ball milling is 30-400 Hz, and the ball milling time is 12-48 h. The average particle size of WS2 powder is 0.1-10 μm, and the content is 3-14 wt%. The average particle size of copper-based composite powder is 80-400 μm.

[0061] Specifically, the mold material in S3 is rubber, silicone sleeve or metal; the pressing forming is molding and cold isostatic pressing, the pressing pressure is 100-500MPa, and the holding time is 30-300s; copper composite material blanks are used to make complex shaped parts, bar blanks, tube blanks, plate blanks and irregular blanks.

[0062] Specifically, the sintering temperature in S4 is 700-900℃, the heating rate is 2-20℃ / min, and the holding time is 1-5h; the relative density of the copper-based composite sintered ingot is 95-99%, the hardness is HRB35-55, the thermal conductivity is 240-320W / (m·K), the tensile strength is 180-300MPa, the yield strength is 120-220MPa, the elongation at break is 5-20%, and the electrical conductivity is 70-90% IACS; using 7075 aluminum alloy as the friction pair, the coefficient of friction is reduced by 30-50% compared to traditional alumina dispersion-strengthened copper.

[0063] Specifically, in S5, hot deformation is achieved through hot extrusion, hot drawing, or other hot deformation processes.

[0064] Specifically, when hot deformation in S5 is hot extrusion, the extrusion ratio is 10:1-80:1; after hot extrusion, the composite material rods or strips are obtained by drawing or cold rolling according to actual use requirements.

[0065] Example 1

[0066] A high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material is a rod material with the following phase composition: 3 wt% W dispersion-reinforced particles, 3 wt% MnS self-lubricating particles, and the remainder being a pure copper matrix; wherein the size of the W dispersion-reinforced particles is 5 nm, the size of the MnS self-lubricating particles is 5 μm, and they are uniformly distributed in the copper matrix.

[0067] A method for preparing the above-mentioned high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material, comprising the following steps:

[0068] S1. Preparation of micron-sized Cu-Mn alloy powder: Electrolytic copper plates and electrolytic manganese ingots were vacuum melted into an alloy melt at a superheating temperature of 250℃. Micron-sized Cu-Mn alloy powder with an average particle size of 74μm was prepared by atomization, wherein the Mn content was 2wt% and the remainder was pure copper. The high-pressure atomization medium was water, and the atomization pressure was 25MPa.

[0069] S2, Preparation of copper-based composite powder: S1 micron-sized Cu-Mn alloy powder was mixed with 4wt% WS2 powder with an average particle size of 100nm, and then mechanical alloying was achieved by planetary ball milling. The grinding ball material was zirconium oxide, the ball-to-powder ratio was 10:1, the ball milling control agent was acetone, the ball milling speed was 200rpm, and the ball milling time was 48h, to obtain copper-based composite powder with an average particle size of 80μm.

[0070] S3. Copper composite material green compact pressing: S2 copper-based composite powder is loaded into a cylindrical silicone sleeve with a size of φ60×60mm. After sealing, it is subjected to cold isostatic pressing with a pressing pressure of 100MPa and a holding time of 300s to obtain a cylindrical green compact of copper composite material with a size of φ50×50mm.

[0071] S4. Preparation of copper-based composite sintered billets: S3 copper composite material cylindrical green billets with a diameter of φ50×50mm were sintered in a hydrogen atmosphere at a temperature of 700℃, a heating rate of 10℃ / min, and a holding time of 2h to obtain copper-based composite sintered billets with a relative density of 98.7%.

[0072] S5. Preparation of copper-based composite material by hot deformation: After the copper-based composite material sintering billet with a relative density of 98.7% in S4 is sintered, it is directly hot extruded without cooling, with an extrusion ratio of 30:1, to obtain a fully densified copper-based composite material profile.

[0073] like Figure 2 As shown, in the phase composition of the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material prepared in this embodiment, the W dispersion-reinforced particles are spherical in shape, and the MnS self-lubricating particles are polygonal in shape.

[0074] The high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material prepared in this embodiment has a hardness of HRB72, a thermal conductivity of 360 W / (m·K), a tensile strength of 516 MPa, a yield strength of 451 MPa, a fracture elongation of 23%, and an electrical conductivity of 89% IACS. Using 7075 aluminum alloy as the friction pair, the coefficient of friction is reduced by 36% compared to traditional alumina dispersion-reinforced copper.

[0075] Example 2

[0076] A high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material is a plate with the following phase composition: 7 wt% W dispersion-reinforced particles, 7 wt% MnS self-lubricating particles, and the remainder being a pure copper matrix; wherein the W dispersion-reinforced particles have a size of 100 nm, the MnS self-lubricating particles have a size of 0.5 μm, and are uniformly distributed in the copper matrix.

[0077] A method for preparing the above-mentioned high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material, comprising the following steps:

[0078] S1. Preparation of micron-sized Cu-Mn alloy powder: Electrolytic copper plates and electrolytic manganese ingots were vacuum melted into an alloy melt with a superheating temperature of 100℃. Micron-sized Cu-Mn alloy powder with an average particle size of 200μm was prepared by atomization process, wherein the Mn content was 5wt% and the remainder was pure copper. The high-pressure atomization medium was nitrogen gas, and the atomization pressure was 2MPa.

[0079] S2, Preparation of copper-based composite powder: S1 micron-sized Cu-Mn alloy powder was mixed with 10 wt% of WS2 powder with an average particle size of 10 μm, and then mechanical alloying was achieved by stirring ball milling. The grinding ball material was alumina, the ball-to-material ratio was 20:1, the ball milling control agent was n-hexane, the ball milling speed was 400 rpm, and the ball milling time was 12 h, to obtain copper-based composite powder with an average particle size of 400 μm;

[0080] S3. Copper composite material green compact pressing: S2 copper-based composite powder is loaded into a cylindrical silicone sleeve with a size of φ60×60mm. After sealing, it is subjected to cold isostatic pressing with a pressing pressure of 500MPa and a holding time of 30s to obtain a cylindrical green compact of copper composite material with a size of φ50×50mm.

[0081] S4. Preparation of copper-based composite sintered billets: Cylindrical green billets of S3 copper composite material with a diameter of φ50×50mm were sintered in a hydrogen atmosphere at a temperature of 900℃, a heating rate of 5℃ / min, and a holding time of 3h to obtain copper-based composite sintered billets with a relative density of 96.2%.

[0082] S5. Preparation of copper-based composite material by hot deformation: After the copper-based composite material sintering billet with a relative density of 96.2% in S4 is sintered, it is directly hot extruded without cooling, with an extrusion ratio of 50:1, to obtain a fully densified copper-based composite material profile.

[0083] like Figure 3 As shown, in the phase composition of the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material prepared in this embodiment, the W dispersion-reinforced particles are ellipsoidal in shape, and the MnS self-lubricating particles are nearly spherical in shape.

[0084] The high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material prepared in this embodiment has a hardness of HRB82, a thermal conductivity of 346 W / (m·K), a tensile strength of 575 MPa, a yield strength of 482 MPa, a fracture elongation of 17%, and an electrical conductivity of 83% IACS. Using 7075 aluminum alloy as the friction pair, the coefficient of friction is reduced by 67% compared to traditional alumina dispersion-reinforced copper.

[0085] Example 3

[0086] A high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material is provided. The composite material is in the shape of a tube and has the following phase composition: 10 wt% W dispersion-reinforcing particles, 8.6 wt% MnS self-lubricating particles, and the remainder being a pure copper matrix. The W dispersion-reinforcing particles have a size of 40 nm, and the MnS self-lubricating particles have a size of 2 μm, which are uniformly distributed in the copper matrix.

[0087] A method for preparing the above-mentioned high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material, comprising the following steps:

[0088] S1. Preparation of micron-sized Cu-Mn alloy powder: Electrolytic copper plates and electrolytic manganese ingots were vacuum melted into an alloy melt with a superheating temperature of 150℃. Micron-sized Cu-Mn alloy powder with an average particle size of 100μm was prepared by atomization process, wherein the Mn content was 6wt% and the remainder was pure copper. The high-pressure atomization medium was argon gas and the atomization pressure was 4MPa.

[0089] S2, Preparation of copper-based composite powder: S1 micron-sized Cu-Mn alloy powder was mixed with 14wt% of WS2 powder with an average particle size of 5μm, and then mechanical alloying was achieved by vibratory ball milling. The grinding ball material was agate, the ball-to-material ratio was 30:1, the ball milling control agent was dichloromethane, the vibration ball milling frequency was 50Hz, and the ball milling time was 24h, to obtain copper-based composite powder with an average particle size of 180μm.

[0090] S3. Copper composite material green compact pressing: S2 copper-based composite powder is loaded into a cylindrical silicone sleeve with a size of φ60×60mm. After sealing, it is subjected to cold isostatic pressing with a pressing pressure of 200MPa and a holding time of 60s to obtain a cylindrical green compact of copper composite material with a size of φ50×50mm.

[0091] S4. Preparation of copper-based composite sintered billet: The cylindrical green billet of S3 copper composite material with a diameter of φ50×50mm was sintered in a hydrogen atmosphere at a temperature of 850℃, a heating rate of 5℃ / min, and a holding time of 3h to obtain a copper-based composite sintered billet with a relative density of 99%.

[0092] S5. Preparation of copper-based composite material by hot deformation: After the copper-based composite material sintering billet with a relative density of 99% in S4 is sintered, it is directly hot extruded without cooling, with an extrusion ratio of 80:1, to obtain a fully densified copper-based composite material profile.

[0093] like Figure 4 As shown, in the phase composition of the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material prepared in this embodiment, the W dispersion-reinforced particles are spherical and ellipsoidal in shape, and the MnS self-lubricating particles are nearly spherical and irregular in shape.

[0094] The high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material prepared in this embodiment has a hardness of HRB91, a thermal conductivity of 317 W / (m·K), a tensile strength of 622 MPa, a yield strength of 584 MPa, a fracture elongation of 11%, and an electrical conductivity of 81% IACS. Using 7075 aluminum alloy as the friction pair, the coefficient of friction is reduced by 80% compared to traditional alumina dispersion-reinforced copper.

[0095] Example 4

[0096] A high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material is provided. The composite material is shaped as a complex-shaped bushing part. Its phase composition is: 5 wt% W dispersion-reinforcing particles, 2 wt% MnS self-lubricating particles, and the remainder is pure copper matrix. The W dispersion-reinforcing particles have a size of 25 nm, and the MnS self-lubricating particles have a size of 3 μm, which are uniformly distributed in the copper matrix.

[0097] A method for preparing the above-mentioned high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material, comprising the following steps:

[0098] S1. Preparation of micron-sized Cu-Mn alloy powder: Electrolytic copper plates and electrolytic manganese ingots are vacuum melted into an alloy melt with a superheating temperature of 200℃. Micron-sized Cu-Mn alloy powder with an average particle size of 74μm is prepared by atomization process, wherein the Mn content is 1.5wt% and the remainder is pure copper. The high-pressure atomization medium can be nitrogen gas, and the atomization pressure is 4MPa.

[0099] S2, Preparation of copper-based composite powder: S1 micron-sized Cu-Mn alloy powder was mixed with 6.5 wt% of WS2 powder with an average particle size of 1 μm, and then mechanical alloying was achieved by planetary ball milling. The grinding ball material was zirconium oxide, the ball-to-powder ratio was 15:1, the ball milling control agent was acetone, the ball milling speed was 270 rpm, and the ball milling time was 30 h, to obtain copper-based composite powder with an average particle size of 82 μm;

[0100] S3. Copper composite material green blank compression forming: S2 copper-based composite powder is loaded into GCr15 alloy mold for compression forming. The compression pressure is 500MPa and the holding time is 60s to obtain copper composite material green blank; copper composite material green blank is used to make complex shaped bushing parts.

[0101] S4. Preparation of copper-based composite material sintered billet: The S3 copper composite material green billet was sintered in a hydrogen atmosphere at a temperature of 900℃, a heating rate of 5℃ / min, and a holding time of 3h to obtain the copper-based composite material sintered billet.

[0102] like Figure 5 As shown, in the phase composition of the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material prepared in this embodiment, the W dispersion-reinforced particles are ellipsoidal in shape, and the MnS self-lubricating particles are irregular in shape.

[0103] The high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material prepared in this embodiment has a relative density of 98.6%, a hardness of HRB47, a thermal conductivity of 286 W / (m·K), a tensile strength of 273 MPa, a yield strength of 180 MPa, a fracture elongation of 12%, and an electrical conductivity of 76% IACS. Using 7075 aluminum alloy as the friction pair, the coefficient of friction is reduced by 43% compared to traditional alumina dispersion-reinforced copper.

[0104] Example 5

[0105] A copper-based composite material with the same phase composition as in Example 1 was prepared. Under the same other process conditions, the sintering preparation process of the copper-based composite material sintered billet was adjusted as follows: the sintering temperature was 600℃, the heating rate was 50℃ / min, and the holding time was 2h, resulting in a copper-based composite material sintered billet with a relative density of 78.9%.

[0106] The copper-based composite material prepared in this embodiment has a hardness of HRB53, a thermal conductivity of 272 W / (m·K), a tensile strength of 340 MPa, a yield strength of 198 MPa, an elongation at break of 13%, and an electrical conductivity of 74% IACS. Using 7075 aluminum alloy as the friction pair, the coefficient of friction is reduced by 26% compared to traditional alumina dispersion-reinforced copper. In contrast, the overall performance of the copper-based composite material prepared in this embodiment is significantly lower than that of Example 1.

[0107] Example 6

[0108] A high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material was prepared using the same process steps as in Example 2. The high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material was a plate with the following phase composition: 1 wt% W dispersion-reinforced particles, 20 wt% MnS self-lubricating particles, and the remainder being a pure copper matrix; wherein the size of the W dispersion-reinforced particles was 8 nm, and the size of the MnS self-lubricating particles was 28 μm.

[0109] In the copper-based composite material prepared in this embodiment, the distribution of MnS self-lubricating particles showed significant segregation. The copper-based composite material had a hardness of HRB44, a thermal conductivity of 259 W / (m·K), a tensile strength of 246 MPa, a yield strength of 160 MPa, an elongation at break of 4%, and an electrical conductivity of 47% IACS. Using 7075 aluminum alloy as the friction pair, the coefficient of friction was reduced by 42% compared to traditional alumina dispersion-reinforced copper. In contrast, the overall performance of the copper-based composite material prepared in this embodiment was significantly lower than that in Example 2.

[0110] The above-mentioned solution proposes a high-strength, high-conductivity, self-lubricating dispersion-reinforced copper composite material, which can solve the technical problems in the prior art, such as the inability to synergistically improve the thermal and electrical conductivity and mechanical properties of copper alloys, the fact that adding dispersion-reinforced metal oxides and doping elements can only improve one aspect of the performance, the high cost of added doping elements, the need for subsequent hot deformation processing after adding ceramic dispersion-reinforced phases and doping elements, and the need for special preparation of dispersion-reinforced metal oxides.

[0111] This invention employs vacuum induction melting to strictly control the melting process, thereby avoiding the oxidation and burn-off of Mn elements and the presence of oxide inclusions in the alloy powder.

[0112] This invention, by selecting the Mn element content, enables the mechanically alloyed copper-based composite powder to generate MnS particles with an appropriate content in situ during the sintering process. This not only provides good self-lubrication and improves friction and wear performance, but also avoids significantly reducing the mechanical properties of the matrix.

[0113] This invention obtains Cu-Mn alloy powder with the required particle size by strictly controlling atomization process parameters such as melt superheat and atomization pressure.

[0114] This invention controls the sintering temperature to prevent the copper grain size from increasing excessively, and also keeps the W particles and MnS particles at the nanometer and submicrometer sizes, respectively. This ensures that the sintered billet, after extrusion, possesses both high strength, high conductivity, and excellent tribological properties, with overall performance improved by more than 50% compared to traditional dispersion-strengthened copper.

[0115] The self-lubricating dispersion-reinforced copper composite material prepared by this invention has fine grains and excellent comprehensive properties such as high strength, high conductivity, and high wear resistance, which are superior to copper-based composite materials prepared by traditional processes.

[0116] The high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material prepared in this invention has a hardness of HRB70-95, a thermal conductivity of 310-360 W / (m·K), a tensile strength of 500-650 MPa, a yield strength of 430-610 MPa, a fracture elongation of 8-25%, and an electrical conductivity of 80-90% IACS. Using 7075 aluminum alloy as the friction pair, the coefficient of friction is reduced by 30-80% compared to traditional alumina dispersion-reinforced copper.

[0117] In summary, compared with traditional chemical methods and other conventional methods such as mixing and external addition, the method of this invention prepares dispersion-reinforced copper composite materials with uniform composition distribution, uniform properties, and synergistic improvement in thermal conductivity, electrical conductivity, mechanical properties, and wear resistance through the preparation of micron-sized Cu-Mn alloy powder, copper-based composite powder, pressing, sintering, and hot deformation. The method is simple and easy to operate, and has unique advantages in the preparation of self-lubricating dispersion-reinforced copper composite materials. The resulting composite material has excellent microstructure and properties, the sintering and extrusion processes are completed continuously, the manufacturing process is short, the production cost is low, and large-scale industrial production can be realized.

[0118] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0119] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be a single item or multiple items.

[0120] It should be understood that, in various embodiments of the present invention, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0121] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material, characterized in that, The high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material is in the form of rods, plates, tubes, or complex-shaped parts. Its phase composition is: 2-10 wt% W dispersion-reinforced particles, 1-10 wt% MnS self-lubricating particles, and the remainder is pure copper matrix; wherein: the size of the W dispersion-reinforced particles is 5-100 nm, the size of the MnS self-lubricating particles is 0.5-5 μm, and they are uniformly distributed in the copper matrix; In the phase composition of the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material, the W dispersion-reinforced particles are spherical or ellipsoidal in shape, and the MnS self-lubricating particles are nearly spherical, polygonal, or irregular in shape. The high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material has a hardness of HRB70-95, a thermal conductivity of 310-360 W / (m·K), a tensile strength of 500-650 MPa, a yield strength of 430-610 MPa, a fracture elongation of 8-25%, and an electrical conductivity of 80-90% IACS. Using 7075 aluminum alloy as the friction pair, the coefficient of friction is reduced by 30-80% compared to traditional alumina dispersion-reinforced copper.

2. A method for preparing a high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material according to claim 1, characterized in that, The preparation method of the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material is as follows: S1. Preparation of micron-sized Cu-Mn alloy powder: Electrolytic copper plate and electrolytic manganese ingot are melted into alloy liquid under vacuum and then atomized to obtain micron-sized Cu-Mn alloy powder. S2, Preparation of copper-based composite powder: S1 micron-sized Cu-Mn alloy powder and WS2 powder were mixed, and then mechanical alloying was achieved by high-energy ball milling to obtain copper-based composite powder; S3, copper composite material green compact pressing: S2 copper-based composite powder is loaded into a mold and pressed to obtain copper composite material green compact; S4. Preparation of copper-based composite sintered billet: The S3 copper composite green billet is sintered in a hydrogen atmosphere to obtain a copper-based composite sintered billet. S5. Preparation of copper-based composite material by hot deformation: After the sintering of S4 copper-based composite material ingot is completed, it is directly hot extruded without cooling to obtain fully densified copper-based composite material profile.

3. The preparation method of the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material according to claim 2, characterized in that, The superheating temperature of the alloy melt in S1 is 100-250℃; the high-pressure atomizing medium can be one or more of nitrogen, argon or water, and the atomizing pressure is 2-25MPa; the average particle size of the micron-sized Cu-Mn alloy powder is 74-200μm, of which the Mn content is 0.7-7wt%, and the remainder is pure copper.

4. The preparation method of the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material according to claim 2, characterized in that, The high-energy ball milling method for S2 can be planetary ball milling, stirred ball milling, or vibratory ball milling. The grinding ball material is one or more of alumina, zirconium oxide, and agate. The ball-to-material ratio is 5:1-30:

1. The ball milling control agent is one or more of acetone, n-hexane, and dichloromethane. The rotation speed of planetary ball milling and stirred ball milling is 100-400 rpm, the frequency of vibratory ball milling is 30-400 Hz, and the ball milling time is 12-48 h. The average particle size of WS2 powder is 0.1-10 μm, and the content is 3-14 wt%. The average particle size of copper-based composite powder is 80-400 μm.

5. The method for preparing high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material according to claim 2, characterized in that, The mold material in S3 is rubber, silicone sleeve or metal; the pressing forming is molding and cold isostatic pressing, the pressing pressure is 100-500MPa, the holding time is 30-300s; copper composite material blanks are used to make complex shaped parts, bar blanks, tube blanks, plate blanks and irregular blanks.

6. The method for preparing high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material according to claim 2, characterized in that, The sintering temperature in S4 is 700-900℃, the heating rate is 2-20℃ / min, and the holding time is 1-5h. The relative density of the copper-based composite sintered ingot is 95-99%, the hardness is HRB35-55, the thermal conductivity is 240-320W / (m·K), the tensile strength is 180-300MPa, the yield strength is 120-220MPa, the elongation at break is 5-20%, and the electrical conductivity is 70-90% IACS. Using 7075 aluminum alloy as the friction pair, the coefficient of friction is reduced by 30-50% compared with traditional alumina dispersion-strengthened copper.

7. The preparation method of the high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material according to claim 2, characterized in that, In S5, hot deformation refers to hot extrusion, hot drawing, or other hot deformation processes.

8. The method for preparing high-strength, high-conductivity, self-lubricating, dispersion-reinforced copper composite material according to claim 2, characterized in that, When hot deformation in S5 is hot extrusion, the extrusion ratio is 10:1-80:1; after hot extrusion, the composite material rods, wires or strips are obtained by drawing or cold rolling according to actual use needs.

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