Tungsten carbide grain reinforced tungsten copper alloy and preparation method thereof

Abstract

The invention discloses a tungsten carbide grain reinforced tungsten-copper alloy and a preparation method thereof.The method comprises the steps that 1, carbon modified tungsten-copper composite powder is dried and then placed in a mold of a tablet press; (2) applying pressure to the powder in the step (1), and pressing into a green body; (3) carrying out high-temperature sintering on the green body obtained in the step (2) in an argon atmosphere to obtain the tungsten carbide grain reinforced tungsten-copper alloy; and (4) machining the tungsten-copper alloy to manufacture the electrical contact of the circuit breaker. Therefore, by adopting the method for preparing the tungsten-copper alloy, in-situ carburization can be carried out on the tungsten surface by utilizing carbon under the condition that tungsten carbide grains are not additionally added, and abnormal growth of the tungsten carbide grains in the sintering process is effectively slowed down; a small amount of tungsten carbide crystal grains are generated in situ, the limitation of unqualified indexes such as alloy brittleness and low density caused by non-uniform traditional additional tungsten carbide crystal grains is avoided, and the prepared tungsten-copper alloy has high strength, high wear resistance and high-temperature ablation resistance.

Description

Technical Field

[0001] The invention belongs to tungsten-copper alloys, and in particular relates to a tungsten carbide grain-reinforced tungsten-copper alloy and a preparation method thereof. Background Art

[0002] Since the melting points and physical properties of tungsten and copper are very different, and the two metals are immiscible, the wettability of the tungsten-copper interface is poor, it is difficult to densify during the sintering process, and it is difficult to obtain the ideal microstructure and performance, which brings many restrictions to the preparation process and performance research of tungsten-copper alloys. It is difficult to achieve effective compounding of copper and tungsten metals with traditional alloy preparation methods. Based on the above problems, many new preparation methods have emerged for cemented carbides with too large a difference in properties between the two components of tungsten and copper, such as infiltration sintering, high-temperature liquid phase sintering, spark plasma sintering, powder injection molding, etc. At present, tungsten-copper alloys generally adopt the preparation method of tungsten skeleton-induced copper infiltration. This method has the advantages of simple preparation principle, easy mass production, and high density of the prepared alloy, but it has high requirements for mechanical equipment, and the porosity of tungsten powder is prone to unevenness during the pressing process, resulting in the inability of liquid copper to penetrate or uneven penetration during the later sintering. After searching the existing technical literature, it was found that the Chinese invention patent with publication number CN117230338 A disclosed a "method for preparing graphene and nano-tungsten carbide synergistically enhanced tungsten-copper alloy electrical contacts". This method mixes graphene powder, nano-tungsten carbide powder, and tungsten powder and then performs hot pressing and sintering to form a tungsten skeleton, and then places a copper block on the surface of the tungsten skeleton at high temperature for copper infiltration. The invention uses graphene and nano-tungsten carbide as additive phases. Graphene can improve the density and hardness of the tungsten-copper alloy. Tungsten carbide will be dispersed in the tungsten matrix and can effectively disperse the arc. The tungsten-copper alloy is synergistically enhanced by graphene and tungsten carbide. However, the disadvantage of this method is that it cannot guarantee the uneven penetration of copper, and it is not clear whether the graphene exists on the surface of the powder or penetrates into the interior of the metal. If the graphene is grown on the surface, then when the powder melts into a molten state, it is very likely that phase-to-phase stratification will occur. Whether the graphene can penetrate into the interior of the tungsten skeleton after agglomeration will affect the density of the tungsten-copper alloy. Therefore, the existing technology of enhancing graphene and tungsten carbide grains to strengthen tungsten copper alloys needs to be improved. Summary of the invention

[0003] The purpose of the present invention is to provide a tungsten carbide grain reinforced tungsten copper alloy, which can effectively slow down the abnormal growth of tungsten carbide grains during the sintering process of tungsten-copper composite powder by utilizing the advantage of in-situ carburization of an ultra-thin carbon layer on the surface of tungsten powder without adding tungsten carbide grains, avoid the limitations of unqualified indicators such as brittleness and low density of the alloy caused by excessive addition of tungsten carbide grains, and the prepared tungsten copper alloy has high strength, high wear resistance and high temperature ablation resistance.

[0004] Another object of the present invention is to provide a method for preparing a tungsten carbide grain-reinforced tungsten-copper alloy.

[0005] The purpose of the present invention is achieved through the following technical solutions.

[0006] A tungsten carbide grain-reinforced tungsten-copper alloy is prepared by the following methods in sequence: (1) Dry the carbon-modified tungsten-copper composite powder and place it in the mold of a tablet press; (2) applying pressure to the powder obtained in step (1) to form a green embryo; (3) Sintering the green body in step (2) at high temperature under an argon atmosphere to obtain a tungsten carbide grain-reinforced tungsten-copper alloy.

[0007] According to the tungsten carbide grain-reinforced tungsten-copper alloy obtained by the present invention, the carbon-modified tungsten-copper composite powder is dried and placed in a mold, and the mold containing the carbon-modified tungsten-copper composite powder is subjected to high-temperature sintering under argon protection conditions to obtain the tungsten-copper alloy. The present invention uses carbon-modified tungsten-copper composite powder as the only raw material and combines it with high-temperature solid-phase sintering technology to prepare tungsten-copper alloy, which has the following advantages: (1) The carbon layer grown in situ on the surface of the tungsten-copper composite powder can not only promote the in-situ carburization of the tungsten surface during the sintering process, but also generate a small amount of tungsten carbide grains in situ and disperse them in the tungsten-copper matrix, which can significantly enhance the mixing uniformity between the composite powders. By in-situ generating tungsten carbide grains on the surface of the carbon-modified tungsten-copper composite powder, on the one hand, during the sintering process, the carbon layer effectively strengthens the surface bonding force between tungsten carbide, tungsten and copper, which can effectively slow down the agglomeration of the tungsten-copper composite powder during the sintering process. On the other hand, the carbon layer as free carbon can be used to carbonize tungsten to generate partial tungsten carbide particles. In addition, the thickness and carbon content of the carbon layer in the tungsten-copper composite powder can be adjusted to meet the requirements of preparing alloys with different properties; (2) Since the present invention does not need to add tungsten carbide as a grain reinforcing agent, it can effectively avoid the limitations of unqualified indicators such as alloy brittleness and low density caused by excessive addition of grain reinforcing agent; (3) The existing technology of adding graphene and tungsten carbide to tungsten-copper composite powder and combining it with a high-temperature sintering process to prepare tungsten-copper alloy has the limitations of complex ball milling process of graphene and tungsten carbide, and graphene and tungsten carbide cannot be uniformly mixed with tungsten-copper composite powder. The present invention uses carbon-modified tungsten-copper composite powder as the only raw material for preparing tungsten carbide grain-enhanced tungsten-copper alloy, eliminating the high-energy ball milling mixing process, the process is simpler, and the uniformity of the obtained tungsten carbide particles uniformly mixed in the tungsten-copper alloy is better. Therefore, the tungsten-copper alloy obtained by the present invention has high hardness, friction resistance and ablation resistance.

[0008] In addition, the present invention may also have the following additional technical features: In step (1), the total carbon content of the tungsten-copper composite powder is 0.1-1 wt%. This can not only effectively slow down the abnormal growth of tungsten and copper grains during sintering, but also carbonize the tungsten in the tungsten-copper composite powder to control the content of WC grains to 0.5%-3 wt%.

[0009] In step (1), the free carbon content of the carbon-modified tungsten-copper composite powder is 0.01-0.5 wt %, which is beneficial to improving the density and hardness of the alloy.

[0010] In step (1), the thickness of the carbon layer in the carbon-modified tungsten-copper composite powder is 1-10 nm.

[0011] In step (1), the particle size of the tungsten powder of the carbon-modified tungsten-copper composite powder is 2-10 μm, and the particle size of the copper powder is 10-25 μm, so that the two powder particles are in better contact with each other.

[0012] In step (1), the mass ratio of tungsten powder to copper powder in the carbon-modified tungsten-copper composite powder is 8:2-6:4, thereby better exerting the role of the tungsten skeleton.

[0013] In step (2), the inner wall of the mold needs to be wiped clean with anhydrous ethanol and air-dried to prevent the mold from causing component contamination to the tungsten copper green embryo.

[0014] In step (2), the pressing pressure of the carbon-modified tungsten-copper composite powder in the mold is 30-40 MPa. Thus, the size and shape of the carbon-modified tungsten-copper composite powder can be kept unchanged under high stress.

[0015] In step (2), the pressing time of the carbon-modified tungsten-copper composite powder in the mold is 5 to 30 minutes. Thus, the size and shape of the composite powder can be kept unchanged over a certain period of time.

[0016] Step (3) includes: placing the mold containing the carbon-modified tungsten-copper composite powder green body obtained in step (2) in a sintering chamber, wherein the initial pressure in the sintering chamber is 0-20 MPa. Then, in an argon atmosphere, the temperature is 1-10 °C min -1 The temperature was raised to 850~1000℃ at a speed of 1~10℃ min, kept at this temperature for 30~120 min, and then -1 When the temperature drops to 600°C, the program stops running, and then the sample is taken out after cooling to room temperature in the furnace.

[0017] The tungsten carbide grain-reinforced tungsten-copper alloy prepared by the present invention can be machined according to a customized size drawing, thereby obtaining a tungsten-copper alloy electrical contact with high strength, high wear resistance and high temperature ablation resistance.

[0018] A method for preparing a tungsten carbide grain-reinforced tungsten-copper alloy, comprising the following steps: (1) Dry the carbon-modified tungsten-copper composite powder and place it in the mold of a tablet press; (2) applying pressure to the powder obtained in step (1) to form a green embryo; (3) Sintering the green body in step (2) at high temperature under an argon atmosphere to obtain a tungsten carbide grain-reinforced tungsten-copper alloy.

[0019] In addition, the present invention may also have the following additional technical features: In step (1), the total carbon content of the tungsten-copper composite powder is 0.1-1 wt%. This can not only effectively slow down the abnormal growth of tungsten and copper grains during sintering, but also carbonize the tungsten in the tungsten-copper composite powder to control the content of WC grains to 0.5%-3 wt%.

[0020] In step (1), the free carbon content of the carbon-modified tungsten-copper composite powder is 0.01-0.5 wt %, which is beneficial to improving the density and hardness of the alloy.

[0021] In step (1), the thickness of the carbon layer in the carbon-modified tungsten-copper composite powder is 1-10 nm.

[0022] In step (1), the particle size of the tungsten powder of the carbon-modified tungsten-copper composite powder is 2-10 μm, and the particle size of the copper powder is 10-25 μm, so that the two powder particles are in better contact with each other.

[0023] In step (1), the mass ratio of tungsten powder to copper powder in the carbon-modified tungsten-copper composite powder is 8:2-6:4, thereby better exerting the role of the tungsten skeleton.

[0024] In step (2), the inner wall of the mold needs to be wiped clean with anhydrous ethanol and air-dried to prevent the mold from causing component contamination to the tungsten copper green embryo.

[0025] In step (2), the pressing pressure of the carbon-modified tungsten-copper composite powder in the mold is 30-40 MPa. Thus, the size and shape of the carbon-modified tungsten-copper composite powder can be kept unchanged under high stress.

[0026] In step (2), the pressing time of the carbon-modified tungsten-copper composite powder in the mold is 5 to 30 minutes. Thus, the size and shape of the composite powder can be kept unchanged over a certain period of time.

[0027] Step (3) includes: placing the mold containing the carbon-modified tungsten-copper composite powder green body obtained in step (2) in a sintering chamber, wherein the initial pressure in the sintering chamber is 0-20 MPa. Then, in an argon atmosphere, the temperature is 1-10 °C min -1 The temperature was raised to 850~1000℃ at a speed of 1~10℃ min, kept at this temperature for 30~120 min, and then-1 When the temperature drops to 600°C, the program stops running, and then the sample is taken out after cooling to room temperature in the furnace.

[0028] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 1 is the metallographic structure diagram of the tungsten-copper alloy obtained in Examples 1 to 4.

[0030] Figure 2 The figure is a comparison of the mechanical properties of the tungsten copper alloys obtained in Examples 1 to 4. DETAILED DESCRIPTION

[0031] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0032] The present invention proposes a method for preparing a tungsten carbide grain-enhanced tungsten-copper alloy and a method for preparing the same. According to an embodiment of the present invention, the method comprises: Step (1): After drying, the carbon-modified tungsten-copper composite powder is placed in a tablet press mold, and pressure is applied to press it into a green embryo. In this step, the weighed carbon-modified tungsten-copper composite powder is first placed in a vacuum drying oven (a conventional device in the art) for drying, and then the dried carbon-modified tungsten-copper composite powder is filled into a cylindrical mold with an internal cavity diameter of 20-50 mm. The inventors found that the carbon layer grown in situ on the surface of the tungsten-copper composite powder can not only promote the in-situ carburization of the tungsten surface during the sintering process, but also generate a small amount of tungsten carbide grains in situ and disperse them in the tungsten matrix, which can significantly enhance the mixing uniformity between the composite powders. By in-situ growing a carbon layer on the surface of the tungsten-copper composite powder, on the one hand, during the sintering process, the carbon layer effectively strengthens the surface bonding force between tungsten carbide, tungsten and copper, which can effectively slow down the significant agglomeration of the tungsten-copper composite powder during the sintering process. On the other hand, the carbon layer can be used as free carbon to carbonize tungsten and generate tungsten carbide grains in situ. In addition, the thickness and carbon content of the carbon layer in the carbon-modified tungsten-copper composite powder can be adjusted to meet the requirements of preparing alloys with different properties. Furthermore, the total carbon content of the carbon-modified tungsten-copper composite powder is 0.1~1 wt%. The free carbon content is 0.01~0.5wt%. The thickness of the carbon layer is 0~10 nm, preferably 3~5 nm. The particle size of the tungsten powder is 2~10μm, and the particle size of the copper powder is 10~25μm.

[0033] Step (2): Under argon atmosphere, the mold containing the carbon-modified tungsten-copper composite powder obtained in step (1) is subjected to high-temperature solid-phase sintering.

[0034] In this step, the mold containing the carbon-modified tungsten-copper composite powder obtained in step (1) is subjected to high-temperature solid-phase sintering under argon atmosphere to obtain a tungsten-copper alloy, and the alloy is mechanically processed. Preferably, the process is carried out in a high-temperature sintering furnace, and the specific type of the sintering furnace is not particularly limited, as long as the above-mentioned function can be achieved.

[0035] Furthermore, the mold containing the carbon-modified tungsten-copper composite powder obtained in step (1) is placed in a sintering chamber, and the initial pressure in the sintering chamber of the sintering furnace is 0-20 MPa. Then, argon gas is introduced, and then the temperature is set at 1-10 °C min -1 , preferably 5~10℃ min -1 Heat up to 850~1000℃ at a speed of 100~200℃, keep warm for 30~120 min, and heat for 1~10℃ min -1 The program stops running when it drops to 600°C, then the furnace is cooled to room temperature, and the sample is taken out. On the one hand, if there are more than two components in the powder compact, the sintering temperature is above the melting point of a certain component, resulting in a small amount of liquid phase in the powder compact during sintering. The inventors found that when sintering carbon-modified tungsten-copper composite powder, if the sintering temperature is higher than the melting point of copper, the copper melts into liquid and leaks out from the pores on the surface of the blank. This phenomenon causes severe deformation and cracking of the sample. Therefore, the sintering temperature of the present invention is set below the melting point of the composite powder. On the other hand, slowing down the cooling rate is to eliminate the internal stress of the sample by extending the cooling time to prevent cracks from occurring after the sample is cooled.

[0036] The method of the present invention uses carbon-modified tungsten-copper composite powder as the only raw material and combines it with high-temperature solid-phase sintering technology to prepare tungsten-copper alloy, which has the following advantages: (1) The carbon layer grown in situ on the surface of the tungsten-copper composite powder can not only promote the in-situ carburization of the tungsten surface during the sintering process, but also generate a small amount of tungsten carbide grains in situ and disperse them in the tungsten matrix, which can significantly enhance the mixing uniformity between the composite powders. By in-situ growing tungsten carbide on the surface of the tungsten-copper composite powder, on the one hand, the carbon layer effectively strengthens the surface bonding force between tungsten carbide, tungsten and copper during the sintering process, which can effectively slow down the significant agglomeration of particles of the tungsten-copper composite powder during the sintering process. On the other hand, the carbon layer as free carbon can be used to carbonize tungsten to generate partial tungsten carbide particles. In addition, the thickness and carbon content of the carbon layer in the tungsten-copper composite powder can be adjusted to meet the requirements for preparing alloys with different properties; (2) Since the present application does not need to add tungsten carbide as a grain reinforcing agent, it can effectively avoid the limitations of unqualified indicators such as alloy brittleness and low density caused by excessive addition of grain reinforcing agent; (3) The existing technology of adding graphene and tungsten carbide to tungsten-copper composite powder and combining it with a high-temperature sintering process to prepare tungsten-copper alloy has the limitations of complex ball milling process of graphene and tungsten carbide, and graphene and tungsten carbide cannot be evenly mixed with tungsten-copper composite powder. The present invention uses carbon-modified tungsten-copper composite powder as the only raw material for preparing tungsten-copper alloy, eliminating the high-energy ball milling mixing process, the process is simpler, and the obtained tungsten carbide particles are evenly mixed. The density of the tungsten-copper alloy is better. Therefore, the tungsten-copper alloy prepared by the method of the present invention has high hardness, friction resistance and ablation resistance.

[0037] The embodiments of the present invention are described in detail below. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention. In addition, if not explicitly stated, all reagents used in the following embodiments are commercially available, or can be synthesized according to this article or known methods, and the reaction conditions not listed are also easily available to those skilled in the art. Example 1

[0038] Step (1): Place tungsten-copper composite powder (tungsten content 60%, average particle size of powder: 2 μm tungsten powder and 10 μm copper powder) in a drying oven for 1 h, and then place it in a tablet press mold with a clean inner wall, an internal cavity diameter of 20 mm, and a maximum compressive strength of 100 MPa.

[0039] Step (2): The powder is pressed into a green embryo by applying a pressure of 35 MPa.

[0040] Step (3): Place the green embryo in the middle of the sintering furnace cavity, open the argon valve and introduce argon gas at 10℃ min -1The heating rate was from room temperature to 900 °C, and the temperature was kept for 2 h. After the temperature was kept, the temperature was increased by 10 °C min -1 When the cooling rate drops to 600℃, the program stops running, and then it is cooled with the furnace and taken out for mechanical processing to obtain tungsten copper alloy. Example 2

[0041] Step (1): Place the carbon-modified tungsten-copper composite powder (tungsten content 80%, in-situ grown carbon layer, total carbon content 0.5 wt %, free carbon content 0.05 wt %, carbon layer thickness 5 nm, tungsten powder average particle size 2 μm, copper powder average particle size 10 μm) in a drying oven for 1 h, and then place it in a tablet press mold with a clean inner wall, an internal cavity diameter of 20 mm, and a maximum compressive strength of 100 MPa.

[0042] Step (2): The powder is pressed into a green embryo by applying a pressure of 35 MPa.

[0043] Step (3): Place the green embryo in the middle of the sintering furnace cavity, open the argon valve and introduce argon gas at 10℃ min -1 The heating rate was from room temperature to 850℃, and the temperature was kept for 2 h. After the temperature was kept for 2 h, the temperature was increased by 10℃ min -1 When the cooling rate drops to 600℃, the program stops running, and then it is cooled to room temperature with the furnace, taken out for mechanical processing, and tungsten carbide grain-reinforced tungsten-copper alloy is obtained. Example 3

[0044] Step (1): Place the carbon-modified tungsten-copper composite powder (tungsten content 70%, in-situ grown carbon layer, total carbon content 1wt%, free carbon content 0.5wt%, carbon layer thickness 10nm, tungsten powder average particle size 5μm, copper powder average particle size 20μm) in a drying oven for 2 hours, and then place it in a tablet press mold with a clean inner wall, an internal cavity diameter of 20mm, and a maximum compressive strength of 100MPa.

[0045] Step (2): The powder is pressed into a green embryo by applying a pressure of 40 MPa.

[0046] Step (3): Place the green embryo in the middle of the sintering furnace cavity, open the argon valve and introduce argon gas at 5℃ min -1 The heating rate was from room temperature to 950℃, and the temperature was kept for 1.5 h. After the temperature was kept, the temperature was increased by 5℃ min -1 When the cooling rate drops to 600℃, the program stops running, and then it is cooled to room temperature with the furnace, taken out for mechanical processing, and tungsten carbide grain-reinforced tungsten-copper alloy is obtained. Example 4

[0047] Step (1): Place the carbon-modified tungsten-copper composite powder (tungsten content 60%, in-situ grown carbon layer, total carbon content 0.1 wt %, free carbon content 0.01 wt %, carbon layer thickness 1 nm, tungsten powder average particle size 10 μm, copper powder average particle size 25 μm) in a drying oven for 1 h, and then place it in a tablet press mold with a clean inner wall, an internal cavity diameter of 20 mm, and a maximum compressive strength of 100 MPa.

[0048] Step (2): The powder is pressed into a green embryo by applying a pressure of 30 MPa.

[0049] Step (3): Place the green embryo in the middle of the sintering furnace cavity, open the argon valve and introduce argon at a rate of 1°C min -1 The heating rate was from room temperature to 1000℃, and the temperature was kept for 0.5 h. After the temperature was kept, the temperature was increased by 1℃ min -1 When the cooling rate drops to 600℃, the program stops running, and then it is cooled to room temperature with the furnace, taken out for mechanical processing, and tungsten carbide grain-reinforced tungsten-copper alloy is obtained.

[0050] The relevant properties of the tungsten copper alloy prepared in Examples 1-4 are as follows: Figure 1-2 shown.

[0051] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A tungsten carbide grain-reinforced tungsten-copper alloy, characterized in that: It is prepared by the following methods: (1) Dry the carbon-modified tungsten-copper composite powder and place it in the mold of a tablet press; (2) applying pressure to the powder obtained in step (1) to form a green embryo; (3) sintering the green body in step (2) at high temperature under an argon atmosphere to obtain a tungsten carbide grain-reinforced tungsten-copper alloy; In step (1), the total carbon content of the tungsten-copper composite powder is 0.1-1 wt%; the free carbon content of the carbon-modified tungsten-copper composite powder is 0.01-0.5 wt%; the thickness of the carbon layer in the carbon-modified tungsten-copper composite powder is 1-10 nm; the tungsten powder particle size of the carbon-modified tungsten-copper composite powder is 2-10 μm, and the copper powder particle size is 10-25 μm; the mass ratio of tungsten powder to copper powder of the carbon-modified tungsten-copper composite powder is 8:2-6:

4.

2. The tungsten carbide grain-reinforced tungsten-copper alloy according to claim 1, characterized in that: In step (2), the pressing pressure of the carbon-modified tungsten-copper composite powder in the mold is 30-40 MPa; and the pressing time of the carbon-modified tungsten-copper composite powder in the mold is 5-30 min.

3. The tungsten carbide grain-reinforced tungsten-copper alloy according to claim 1, characterized in that: Step (3) comprises: placing the mold containing the carbon-modified tungsten-copper composite powder green body obtained in step (2) in a sintering chamber, and then sintering the green body at 1-10°C min in an argon atmosphere. -1 Heat up to 850~1000℃ at a rate of 1000℃ and keep warm for 30~120 min.

4. The tungsten carbide grain-reinforced tungsten-copper alloy according to claim 3, characterized in that: After keeping warm at 1~10℃ min -1 When the temperature drops to 600°C, the program stops running, and then the sample is taken out after cooling to room temperature in the furnace.

5. A method for preparing a tungsten carbide grain-reinforced tungsten-copper alloy, characterized in that: Follow these steps: (1) Dry the carbon-modified tungsten-copper composite powder and place it in the mold of a tablet press; (2) applying pressure to the powder obtained in step (1) to form a green embryo; (3) sintering the green body in step (2) at high temperature under an argon atmosphere to obtain a tungsten carbide grain-reinforced tungsten-copper alloy; In step (1), the total carbon content of the tungsten-copper composite powder is 0.1-1 wt%; the free carbon content of the carbon-modified tungsten-copper composite powder is 0.01-0.5 wt%; the thickness of the carbon layer in the carbon-modified tungsten-copper composite powder is 1-10 nm; the tungsten powder particle size of the carbon-modified tungsten-copper composite powder is 2-10 μm, and the copper powder particle size is 10-25 μm; the mass ratio of tungsten powder to copper powder of the carbon-modified tungsten-copper composite powder is 8:2-6:

4.

6. The method for preparing a tungsten carbide grain-reinforced tungsten-copper alloy according to claim 5, characterized in that: In step (2), the pressing pressure of the carbon-modified tungsten-copper composite powder in the mold is 30-40 MPa; and the pressing time of the carbon-modified tungsten-copper composite powder in the mold is 5-30 min.

7. The method for preparing a tungsten carbide grain-reinforced tungsten-copper alloy according to claim 5, characterized in that: Step (3) comprises: placing the mold containing the carbon-modified tungsten-copper composite powder green body obtained in step (2) in a sintering chamber, and then sintering the green body at 1-10°C min in an argon atmosphere. -1 Heat up to 850~1000℃ at a rate of 1000℃ and keep warm for 30~120 min.

8. The method for preparing a tungsten carbide grain-reinforced tungsten-copper alloy according to claim 7, characterized in that: After keeping warm, 1~10℃ min -1 When the temperature drops to 600°C, the program stops running, and then the sample is taken out after cooling to room temperature in the furnace.

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