A Cu-Fe-C composite material, preparation method and application thereof

Abstract

The present invention provides a Cu-Fe-C composite material, a preparation method and application thereof; the preparation method of the composite material Cu-Fe-C comprises the following steps: raw materials are prepared according to the required proportion of the reaction; Fe and C are smelted into a master alloy of Fe-C; Cu is placed in a crucible of a vacuum medium-frequency induction melting furnace, vacuumed and heated until Cu is completely melted, and the Fe-C master alloys in the charging hopper are respectively added into the crucible of the vacuum medium-frequency induction melting furnace; after adding the master alloy, the reaction is allowed to proceed for a period of time, and then cast into a casting mold; the obtained ingot is subjected to a solid solution treatment and an aging treatment to prepare a copper-based composite material Cu-Fe-C. The method is simple and easy to implement, and a copper-based composite material with high strength, good electrical conductivity and high wear resistance can be prepared by the method.

Description

Technical Field

[0001] The invention relates to copper-based composite material technology, and in particular to a Cu-Fe-C composite material, a preparation method and application thereof. Background Art

[0002] Compared with traditional copper alloys, Cu-C composite materials have the advantages of excellent electrical and thermal conductivity and high strength of copper matrix, as well as excellent lubrication and arc erosion resistance of carbon. They are the preferred materials for preparing high-speed railway pantograph slides, new generation high-speed motor brushes, electronic packaging materials, electromagnetic gun guide rails and other components. At present, a variety of methods for preparing Cu-C composite materials have been developed, such as casting, powder metallurgy, liquid phase infiltration, spark plasma sintering, diffusion bonding, etc. Among them, the casting method for preparing Cu-C composite materials has the advantages of low cost, easy control of parameters, and simple process.

[0003] However, copper and carbon do not wet or react, and it is difficult to add carbon materials into the copper matrix and disperse them evenly. This problem of copper and carbon being difficult to fuse well has greatly restricted the development of Cu-C composite materials. How to perfectly add carbon to copper to form a graphite phase with a good phase interface and uniform distribution, and obtain a high-performance Cu-C bulk material with integrated structure and function, is an urgent problem to be solved in this field. Summary of the invention

[0004] The purpose of the present invention is to propose a preparation method for introducing carbon into a matrix by introducing an intermediate component Fe that is both solid-soluble in copper and has good affinity with carbon, in order to solve the problem that the interface between copper and carbon in the existing Cu-C system materials is prone to become a weak link due to the non-wetting between copper and carbon, thus affecting the service performance of the material. The method is simple and easy to implement. A Cu-Fe-C composite material with high strength, good electrical conductivity and high wear resistance can be prepared by using the method.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing a Cu-Fe-C composite material:

[0006] The preparation method of the Cu-Fe-C composite material comprises the following steps:

[0007] (1) preparing raw materials of Cu block, Fe particles and graphite in the required proportions, wherein Fe element is added according to its solid solubility in Cu at its limit solid solubility content;

[0008] (2) Fe and graphite are melted into the intermediate alloy Fe-C, so that C can more easily enter the copper matrix during the melting process, facilitating precise control of the composition;

[0009] (3) heating Cu in a vacuum until Cu is completely melted, keeping the temperature for 10-20 minutes, and then adding the Fe-C master alloy prepared in step (2); reacting for a period of time, and casting after the reaction is complete to obtain a cast billet;

[0010] (4) After keeping the temperature at 850-900°C for 0.5-1h, the ingot is hot rolled. After hot rolling, the ingot is solution treated at the temperature of the solid solubility limit of Fe element in copper. The ingot after hot rolling and solid solution treatment is cold rolled. After cold rolling, an aging treatment is performed. The aging treatment temperature and time are based on the precipitation of C element from copper, and finally a Cu-Fe-C composite material is prepared.

[0011] According to the technical solution described above, further, the reaction time in step (3) is 10 to 20 minutes.

[0012] According to the technical solution described above, further, in the step (4), the hot rolling deformation is 40-50%, and the solution treatment comprises the following steps: heating the ingot obtained after hot rolling to a temperature at the solubility limit of Fe element in copper (the embodiment is solution treatment at 950°C), keeping the temperature for 3-4 hours, and cooling.

[0013] According to the technical solution described above, further, in the step (4), the cold rolling deformation is 80% to 90%, and the aging treatment comprises the following steps: heating the casting after hot rolling, solution treatment and cold rolling to an aging temperature of 400 to 600°C, keeping it warm for 1 to 3 hours, and cooling it to room temperature.

[0014] The second aspect of the present invention is to disclose a Cu-Fe-C composite material prepared by the above method, wherein 3wt.%≤Fe≤4wt.%, 0.05wt.%≤C≤0.2wt.%; the balance is Cu. The Cu-Fe-C composite material of the present invention is prepared by a casting method, and a graphite phase is precipitated from a Cu matrix by hot rolling, solid solution, and cold rolling aging methods to improve the wear resistance of the composite material, and finally a Cu-Fe-C composite material with high strength, good electrical conductivity and high wear resistance is obtained.

[0015] In a more preferred embodiment, in the Cu-Fe-C composite material, Fe is 3.5wt.%, 0.07385wt.%≤C≤0.175wt.%; and the balance is Cu.

[0016] The mechanical properties, electrical properties and tribological properties of Cu-Fe-C composite materials can be adjusted by adjusting the proportion of each element in the Cu-Fe-C composite material and changing the content of C (graphite). Among them, adding an appropriate amount of graphite can improve the conductivity of the material, significantly reduce the friction coefficient, and increase the hardness; while appropriately reducing the graphite content can moderately increase the hardness and further optimize the conductivity while maintaining good lubricity.

[0017] The third aspect of the present invention is to disclose the application of the above-mentioned Cu-Fe-C composite material, including its application in the technical fields of preparing high-speed rail pantograph slides, new generation high-speed motor brushes, electronic packaging materials, electromagnetic gun guides, integrated circuit lead frames, high-speed rail contact lines, etc.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1) The Cu-Fe-C composite material prepared by the method of the present invention can improve the wear resistance of the material by adding the C element, and can maintain high electrical conductivity and excellent performance through hot rolling, solid solution and cold rolling aging methods. Therefore, the present invention can prepare a copper-based composite material with good wear resistance, high strength and good electrical conductivity.

[0020] 2) The present invention utilizes casting and heat treatment methods, and has the characteristics of simple process, low cost, and easy industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The scanning electron microscope photos and EDS spectrum analysis of the microstructure of Cu-3.5wt.%Fe-0.175wt.%C after hot rolling, solid solution, cold rolling and aging. They are: The first image in the upper left corner is marked as "Electron Image 24", which is the microstructure of this material. The "Fe Ka1" image below this image shows the characteristics of the observed iron element. On the right, the third image is marked as "Cu La1-2", which indicates the energy level state of the copper element. The last image is marked as "C Ka1-2" to indicate the energy level state of the carbon element.

[0022] The results show that after hot rolling, solution treatment and cold rolling aging, Fe phase and graphite phase were successfully precipitated, and a copper-based composite material with Fe and graphite reinforcement was obtained. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with embodiments:

[0024] Example 1

[0025] This embodiment discloses a preparation method of a Cu-3.5wt.%Fe-0.175wt%C composite material, comprising the following steps:

[0026] (1) preparing raw materials in the required proportions, including: 96.325 parts by weight of Cu blocks, 3.5 parts by weight of Fe particles, and 0.175 parts by weight of graphite C; wherein: the amount of Fe element added is determined according to its solid solubility in Cu, and is added at its limit solid solubility content;

[0027] (2) Smelting Fe and graphite into an intermediate alloy Fe-C. The purpose of first smelting the intermediate alloy is to make it easier for it to enter the copper matrix during the smelting process, reduce volatilization, and facilitate precise control of the composition;

[0028] (3) adding Cu into a crucible of a vacuum medium frequency induction melting furnace and placing a Fe-C master alloy into a hopper; evacuating the furnace and heating until the copper is completely melted and keeping the temperature for 15 minutes, and then adding the Fe-C master alloy obtained in step (2);

[0029] (4) After reacting for 10 minutes, pour into a mold;

[0030] (5) The obtained ingot was kept at 900°C for 1 hour and then hot rolled with a deformation of 50%. After hot rolling, it was solution treated at 950°C for 4 hours and cooled; it was then cold rolled with a deformation of 90%. After cold rolling, it was aged at 500°C for 2 hours and cooled to room temperature, and finally a Cu-Fe-C composite material was obtained.

[0031] After testing, the Cu-3.5wt.%Fe-0.175wt%C composite material prepared in this embodiment has a hardness of 148HV, an electrical conductivity of 55.672%IACS, and a friction coefficient of 0.717 when rubbed for 60 minutes at a sliding speed of 120mm / min and a pressure of 10N.

[0032] Example 2

[0033] This embodiment provides a preparation of a Cu-3.5wt.%Fe-0.07385wt.%C composite material, and the preparation method is basically the same as that of Example 1, except that the C content is 0.07385wt.%.

[0034] After testing, its hardness is 154.78HV, the electrical conductivity is 56.338%IACS, and the friction coefficient is 0.7388 when rubbed for 60 minutes at a pressure of 10N and a sliding speed of 120mm / min.

[0035] Comparison Example

[0036] This comparative example provides a preparation method of a Cu-3.5wt.%Fe composite material, and the preparation method is substantially the same as that of Example 1, except that there is no step of adding C.

[0037] After testing, its hardness is 140.52HV, conductivity is 55.34%IACS, and friction coefficient is 0.753 when rubbing for 60min under 10N pressure and 120mm / min sliding speed. It can be seen that the Cu-3.5wt.%Fe-0.175wt%C composite material with C has higher hardness, higher conductivity, and smaller friction coefficient when rubbing for 60min under 10N pressure and 120mm / min sliding speed than the Cu-3.5wt.%Fe composite material.

[0038] In summary, through the data analysis of Example 1, Example 2 and the control example, the following conclusions can be drawn:

[0039] For the Cu-3.5wt.%Fe-0.175wt%C composite material in Example 1:

[0040] Its hardness is 148 HV, which is higher than that of the Cu-3.5 wt. % Fe composite material (140.52 HV) of the control example, indicating that the overall hardness of the material is improved after a small amount of graphite C is added.

[0041] The electrical conductivity is 55.672% IACS, slightly higher than 55.34% IACS of the control example, indicating that the composite material containing graphite has higher electrical conductivity while ensuring a certain strength.

[0042] The friction coefficient is 0.717, which is lower than that of the control example (0.753) when rubbing for 60 minutes under a pressure of 10N and a sliding speed of 120mm / min, showing better wear resistance and self-lubrication.

[0043] Comparative Example 2 and Example 1:

[0044] In Example 2, the C content is reduced to 0.07385 wt.%, and the hardness is increased to 154.78 HV, which is higher than that of Example 1 and the control example, indicating that the hardness is improved as the C content decreases.

[0045] The electrical conductivity of Example 2 is further improved to 56.338% IACS, which is better than that of Example 1, indicating that under the premise of maintaining a low friction coefficient, appropriately reducing the C content is beneficial to improving the electrical conductivity of the material.

[0046] The friction coefficient is 0.7388, which is slightly higher than that of Example 1 (0.717), but still lower than that of the control example, indicating that even if the C content is reduced, the composite material still has good anti-wear and self-lubricating properties.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a Cu-Fe-C composite material, characterized in that: The Cu-Fe-C composite material contains 3wt.%≤Fe≤4wt.%, 0.05wt.%≤C≤0.2wt.%, and the balance is Cu; and the preparation method thereof comprises the following steps: (1) preparing raw materials of Cu block, Fe particles and graphite in the required proportions, wherein Fe element is added according to its solid solubility in Cu at its limit solid solubility content; (2) Fe and graphite are melted into the intermediate alloy Fe-C, so that C can more easily enter the copper matrix during the melting process, facilitating precise control of the composition; (3) heating Cu in a vacuum until Cu is completely melted, keeping the temperature for 10-20 minutes, and then adding the Fe-C master alloy prepared in step (2); reacting for a period of time, and casting after the reaction is complete to obtain a cast billet; (4) After being kept at 850-900°C for 0.5-1h, the ingot is hot rolled, and the deformation amount of the hot rolling is 40-50%; after hot rolling, the hot rolled piece is subjected to solid solution treatment at the temperature of the solid solubility limit of Fe element in copper, and the solid solution treatment comprises the following steps: heating the ingot obtained after hot rolling to the temperature of the solid solubility limit of Fe element in copper, keeping it warm for 3-4 hours, and cooling; cold rolling the ingot after hot rolling and solid solution treatment, and the deformation amount of the cold rolling is 80-90%; after cold rolling, aging treatment is performed, and the aging treatment temperature and time are based on the precipitation of C element from copper, and finally a Cu-Fe-C composite material is obtained.

2. The method according to claim 1, characterized in that: The reaction time in step (3) is 10-20 minutes.

3. The method according to claim 1, characterized in that: The aging treatment in step (4) comprises the following steps: heating the casting after hot rolling, solution treatment and cold rolling to an aging temperature of 400-600° C., keeping the temperature for 1-3 hours, and cooling to room temperature.

4. The Cu-Fe-C composite material according to claim 1, characterized in that: In the Cu-Fe-C composite material, Fe is 3.5wt.%, 0.07385wt.%≤C≤0.175wt.%; and the balance is Cu.

5. The use of the Cu-Fe-C composite material according to claim 1, characterized in that: The applications include applications in the preparation of high-speed rail pantograph slides, new generation high-speed motor brushes, electronic packaging materials, electromagnetic gun guides, integrated circuit lead frames, and high-speed rail contact line technology.

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