Method for improving tungsten-copper connection interface based on internal oxidation and hydrogen reduction process

Abstract

The invention discloses a method for improving a tungsten-copper connection interface based on internal oxidation and hydrogen reduction processes, and relates to the technical field of tungsten-copper composite material preparation. Firstly, oxides (Cu2O and CuO) or oxygen are added to the surface of a tungsten block for internal oxidation treatment, a nano oxide porous structure is generated on the surface, the surface roughness is improved, then surface oxide impurities are removed through hydrogen reduction, surface holes are reserved, and finally effective combination between tungsten and copper is achieved through spark plasma sintering of the tungsten block subjected to surface treatment and copper powder. Through the internal oxidation process, the influence of a metal alloy layer formed by heterogeneous element brazing filler metal introduced in traditional brazing on the compatibility of a tungsten-copper interface and the stability in a radiation state can be effectively avoided, and through reduction treatment of high-purity hydrogen, the high purity of a base body is kept, and meanwhile a porous structure is generated to strengthen the bonding performance of a connecting layer.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of tungsten-copper composite materials, and in particular to a method for improving a tungsten-copper connection interface based on internal oxidation and hydrogen reduction processes. Background Art

[0002] In nuclear fusion reactors, plasma facing components (PFC) are subjected to extreme thermal environments and strong neutron radiation, and need to have excellent durability and structural integrity. W is selected for its high melting point, excellent high-temperature strength and radiation damage resistance, and it can withstand the direct impact of high-temperature plasma. Cu and its alloys (CuCrZr) have excellent thermal conductivity and can effectively dissipate the internal heat generated at high temperatures, thereby reducing thermal damage. Therefore, composite module metal materials composed of tungsten, copper and copper alloys have excellent application prospects, which poses a challenge to the bonding strength between tungsten and copper. W and Cu are not mutually soluble in each other, and the thermal expansion coefficients are significantly different. There is an increase in internal stress during service, which leads to a decrease in interface strength. Therefore, the development and optimization of W / Cu bonding technology is crucial to improving the performance of diverter components and ensuring the reliable operation of nuclear fusion reactors.

[0003] In order to improve the bonding strength and efficiency between W and Cu, a variety of bonding techniques have been tried, including brazing, diffusion bonding, and explosion welding. 2 -Ni and Ni / Cu can form a metallurgical bonding layer with W or Cu to enhance the interfacial bonding performance. However, the use of the intermediate layer affects the interface compatibility, the microstructural uniformity of the heterogeneous elements in the intermediate layer, the mechanical integrity of the bonding layer, and the stability under radiation conditions. In order to solve the problems caused by heterogeneous element brazing filler metals, surface treatment technology has become an effective alternative, aiming to change the bonding state between W and Cu through surface structure design without introducing additional interlayers or auxiliary phases at the interface. Recent studies have shown that the surface nanostructure obtained by surface treatment significantly improves the interfacial bonding strength of dissimilar metal joints. Traditional mechanical surface treatment methods such as grinding and sandblasting increase the bonding strength of the bonding layer by increasing the surface roughness, but these methods may only be applicable to thick-section components and there is a risk of damage. In contrast, non-mechanical methods, including plasma treatment, laser surface treatment, and anodizing, can provide excellent surface activity and microstructural design capabilities. However, they have not been widely used due to high costs and operating technology.

[0004] As a widely used oxidation process, internal oxidation can oxidize on the metal surface and near the surface through the diffusion and penetration of oxygen in a high temperature environment. These oxides have a large volume, resulting in the formation of internal pores, and then a porous oxide layer is formed on the surface. As a surface treatment method, internal oxidation can control the thickness of the surface oxide layer and the density of the pores by changing the oxygen concentration, temperature and internal oxidation time during the internal oxidation process to regulate the surface roughness. It is easy to control and easy to mass produce. At the same time, the porous structure produced can effectively improve the surface roughness and enhance the surface free energy, which can effectively inhibit crack propagation, increase the bonding strength between copper and tungsten, and improve the toughness of the material connection interface. At the same time, it also avoids the influence of heterogeneous elements on the uniformity of interface bonding and the stability under radiation conditions. Therefore, the method of using the internal oxidation process to improve the bonding strength of the metal bonding layer has excellent prospects and guiding significance. Summary of the invention

[0005] The present invention proposes a method for improving the tungsten-copper connection interface based on internal oxidation and hydrogen reduction processes. The main problem to be solved is the problem that W and Cu cannot be effectively bonded due to the significant difference in thermal expansion coefficients and the inherent immiscibility between W and Cu. The internal oxidation process can effectively avoid the influence of the metal alloy layer formed by the heterogeneous element brazing material introduced by traditional brazing on the compatibility of the tungsten-copper interface and the stability under radiation state, and the reduction treatment of high-purity hydrogen maintains the high purity of the matrix while generating a nanoporous structure to strengthen the bonding performance of the connection layer. The prepared tungsten-copper connection material can be applied to the field of nuclear fusion reactor divertors.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is:

[0007] A method for improving the tungsten-copper connection interface based on internal oxidation and hydrogen reduction processes, wherein a tungsten block is placed in a tube furnace, oxides are added to the surface or internal oxidation treatment is performed at high temperature in an oxygen atmosphere, a nano-oxide porous structure is generated on the surface, and the surface roughness is increased, then hydrogen atmosphere reduction is used to remove surface oxide impurities and retain surface pores, and finally the surface-treated tungsten block and copper powder prepared by mechanical alloying and reduced in a hydrogen atmosphere are densified by spark plasma sintering to achieve effective bonding between tungsten and copper.

[0008] As a preferred technical solution of the present invention, the preparation method specifically comprises the following steps:

[0009] Step 1: Internal oxidation of tungsten block:

[0010] For surface treatment of tungsten block, put the tungsten block into a tube furnace, add oxide on the surface or use oxygen atmosphere, heat up and keep warm for a period of time, take it out and remove the oxide added on the surface to obtain the tungsten block with surface oxidation;

[0011] Step 2: Preparation of copper powder by mechanical alloying:

[0012] Put the copper powder into a planetary ball mill, set the parameters for mechanical alloying for a period of time, and then take it out;

[0013] Step 3: Hydrogen atmosphere reduction:

[0014] The obtained surface oxidized tungsten block and the copper powder obtained by mechanical alloying are placed in a tube furnace and separated from each other, the parameters are adjusted, hydrogen is passed to increase the temperature, and the furnace is taken out after being kept warm for a period of time to obtain reduced copper powder and reduced tungsten blocks with rough surfaces and no impurity oxides;

[0015] Step 4: Sintering and densification of tungsten copper connection materials:

[0016] The rough-surfaced reduced tungsten block and reduced copper powder obtained in step three are subjected to spark plasma sintering to finally obtain a tungsten-copper connection material in which the tungsten-copper interface bonding state is improved by an internal oxidation-reduction process.

[0017] As a further preferred technical solution of the present invention, in the method:

[0018] The oxide used in step 1 is Cu 2 O or CuO. The temperature in the tube furnace is 650-800°C, the holding time is 12h, and the mass ratio of the added oxide to the tungsten block is 4:1.

[0019] The parameters of the planetary ball mill in step 2 are 500 r / min, the ball milling time is 24 h, and the ball-to-material ratio is 7:3.

[0020] The calcination reduction parameters of the tubular furnace in step 3 are: the atmosphere used is H 2 Ar-H with 10% content 2 Mixed gas, heating rate is 5℃ / min, calcination temperature is 600℃, and holding time is 8h.

[0021] The specific steps of sintering densification in step 4 are as follows: loading the internally oxidized and reduced tungsten block into a sintering mold, adding mechanically alloyed copper powder treated with hydrogen atmosphere reduction to the surface of the tungsten block with a rough porous structure, isolating the mold wall and the powder with carbon paper, placing the block in a discharge plasma sintering furnace, and evacuating the sintering furnace; setting the initial pressure to 10 MPa, starting sintering, heating from room temperature to 600°C and keeping the temperature for 5 minutes; then heating to 900°C and keeping the temperature for 5 minutes, manually pressurizing the block to a sintering pressure of 50 MPa during the heating process, and the heating rate is 100°C / min; cooling the block with the furnace after the insulation is completed, taking out the product, and grinding the carbon paper on the surface with a grinder, so as to finally obtain a tungsten-copper connection material with improved tungsten-copper interface bonding state.

[0022] The raw materials used in the present invention are tungsten block, Cu2 O, CuO, after internal oxidation treatment, hydrogen reduction is performed with mechanically alloyed copper powder, followed by spark plasma sintering densification to obtain a tungsten-copper connection material with improved tungsten-copper interface bonding state. The prepared tungsten-copper connection material can be used as a composite module in a nuclear fusion reactor. Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. The internal oxidation process can effectively form a highly active nanoporous structure on the metal surface, improve surface roughness and enhance surface free energy, effectively inhibit crack propagation, change the tensile fracture mode from brittle fracture to ductile fracture, and improve the toughness of the material connection interface. At the same time, it can effectively avoid the influence of the brazing material and metal alloy layer introduced by traditional brazing and chemical vapor deposition methods on the interface compatibility of tungsten and copper, the uniformity of heterogeneous elements, and the stability under radiation conditions. The internal oxidation process is simple to operate and easy to produce, avoiding the high cost and low efficiency of traditional anodizing and laser surface treatment, and can quickly obtain a porous structure.

[0024] 2. As an effective surface modification technology, internal oxidation can control the thickness of the surface oxide layer and the density of pores to regulate the surface roughness by changing the oxygen concentration, temperature and internal oxidation time during the internal oxidation process. It is easy to control, easy to scale production, and has economic value.

[0025] 3. Surface treatment technology has become an effective solution. It changes the bonding state between W and Cu by designing the surface structure without introducing additional interlayers or auxiliary phases at the interface. It is suitable for thick and thin parts of different sizes. At the same time, internal oxidation surface treatment avoids the risk of damage caused by traditional mechanical surface treatment methods such as grinding and sandblasting due to the influence of heterogeneous elements in the intermediate layer on the uniformity of the microstructure.

[0026] 4. The hydrogen reduction process can avoid the influence of impurity phases during the tungsten-copper connection process, does not introduce other impurity elements, maintains the high purity of the matrix, and minimizes the impact on the matrix performance.

[0027] 5. Spark plasma sintering significantly shortens the processing time. Precise control of sintering parameters allows fine-tuning of the microstructure at the interface and optimization of mechanical and thermal properties. Rapid heating and cooling cycles allow lower processing temperatures, reduce the risk of thermal damage and maintain microstructural integrity. Uniaxial pressure and pulsed direct current are used to induce rapid heating to improve bonding quality, resulting in dense and uniform bonds with minimal porosity and defects, resulting in excellent bonding strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The process flow chart of the present invention for improving the interface bonding state of tungsten-copper connection materials.

[0029] Figure 2This is a SEM image of the oxidized and reduced tungsten surface in the tungsten-copper connecting material with improved interface bonding state according to Example 1 of the present invention.

[0030] Figure 3 This is a SEM of the coverage depth of the porous structure on the surface of the tungsten-copper connection material for improving the interface bonding state in Example 1 of the present invention.

[0031] Figure 4 This is the EDS spectrum diagram of the connection interface of the tungsten-copper connection material with improved interface bonding state in Example 1 of the present invention.

[0032] Figure 5 This is a SEM image of the fracture surface of the connection interface of the tungsten-copper connection material with improved interface bonding state in Example 1 of the present invention.

[0033] Figure 6 This is a comparison chart of the mechanical properties of tungsten-copper connection materials improved by the interface bonding state of Example 1 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0034] See also Figure 1 As shown, the present invention proposes a method for improving the tungsten-copper connection interface based on internal oxidation and hydrogen reduction process, wherein a tungsten block is placed in a tube furnace, and an oxide (Cu 2 O or CuO) or internal oxidation treatment is carried out at high temperature in oxygen atmosphere to generate nano oxide porous structure on the surface and increase surface roughness; then hydrogen atmosphere is used for reduction to remove surface oxide impurities and retain surface pores, and finally the surface treated tungsten block is densified by spark plasma sintering with mechanical alloying copper powder which has been reduced in hydrogen atmosphere to realize effective bonding between tungsten and copper.

[0035] The present invention is further described in detail below in conjunction with embodiments and drawings.

[0036] Example 1

[0037] The method for preparing the tungsten copper connection material in this embodiment is as follows:

[0038] Step 1: Internal oxidation of tungsten block:

[0039] For surface treatment of tungsten block, put the tungsten block into a tube furnace and add Cu 2 O, Cu 2 The mass ratio of the added amount of O to the tungsten block is 4:1. The temperature is gradually raised to 700°C and kept for 12 hours. After being taken out, the oxide added on the surface is removed to obtain a tungsten block with surface oxidation.

[0040] Step 2: Preparation of copper powder by mechanical alloying:

[0041] Put the copper powder into a planetary ball mill, set the parameters of the ball mill to 500r / min, the ball milling time to 24h, the ball-to-material ratio to 7:3, and take it out after mechanical alloying.

[0042] Step 3: Hydrogen atmosphere reduction:

[0043] The surface oxidized tungsten block and the copper powder obtained by mechanical alloying are placed in a tubular furnace and separated from each other. The heating rate is adjusted to 5°C / min, the calcination temperature is 600°C, the insulation time is 8h, the temperature is increased by hydrogen, and the reduced copper powder and the reduced tungsten block with a rough surface and no impurity oxide are obtained after a period of insulation.

[0044] Step 4: Sintering and densification of tungsten copper connection materials:

[0045] The rough-surfaced reduced tungsten block and reduced copper powder obtained in step three are subjected to spark plasma sintering, the internally oxidized and reduced tungsten block is loaded into a sintering mold, mechanically alloyed copper powder reduced in hydrogen atmosphere is added to the rough porous surface of the tungsten block, the mold wall and the powder are isolated by carbon paper, and the block is placed in a spark plasma sintering furnace, and the sintering furnace is evacuated; the initial pressure is set to 10 MPa, sintering is started, the temperature is increased from room temperature to 600°C and kept warm for 5 minutes; the temperature is then increased to 900°C and kept warm for 5 minutes, and during the heating process, the sintering pressure is manually increased to 50 MPa, and the heating rate is 100°C / min; after the insulation is completed, the block is cooled with the furnace, the product is taken out, and the carbon paper on the surface is polished with a grinder, and finally a tungsten-copper connection material with improved tungsten-copper interface bonding state by an internal oxidation-reduction process is obtained.

[0046] Example 2

[0047] The method for preparing the tungsten copper connection material in this embodiment is as follows:

[0048] Step 1: Internal oxidation of tungsten block:

[0049] For the surface treatment of the tungsten block, put the tungsten block into a tube furnace, add CuO on the surface, and the mass ratio of CuO to the tungsten block is 4:1. Gradually increase the temperature to 700℃, keep the temperature for 12h, take it out and remove the oxide added on the surface to obtain a tungsten block with surface oxidation.

[0050] Step 2: Preparation of copper powder by mechanical alloying:

[0051] Put the copper powder into a planetary ball mill, set the parameters of the ball mill to 500r / min, the ball milling time to 24h, the ball-to-material ratio to 7:3, and take it out after mechanical alloying.

[0052] Step 3: Hydrogen atmosphere reduction:

[0053] The surface oxidized tungsten block obtained in step 1 and the copper powder obtained by mechanical alloying are placed in a tubular furnace and separated from each other. The heating rate is adjusted to 5°C / min, the calcination temperature is 600°C, the insulation time is 8h, the temperature is increased by hydrogen, and the reduced copper powder and the reduced tungsten block with a rough surface and no impurity oxide are obtained after a period of insulation.

[0054] Step 4: Sintering and densification of tungsten copper connection materials:

[0055] The rough-surfaced reduced tungsten block and reduced copper powder obtained in step three are subjected to spark plasma sintering, the internally oxidized and reduced tungsten block is loaded into a sintering mold, mechanically alloyed copper powder reduced in hydrogen atmosphere is added to the rough porous surface of the tungsten block, the mold wall and the powder are isolated by carbon paper, and the block is placed in a spark plasma sintering furnace, and the sintering furnace is evacuated; the initial pressure is set to 10 MPa, sintering is started, the temperature is increased from room temperature to 600°C and kept warm for 5 minutes; the temperature is then increased to 900°C and kept warm for 5 minutes, and during the heating process, the sintering pressure is manually increased to 50 MPa, and the heating rate is 100°C / min; after the insulation is completed, the block is cooled with the furnace, the product is taken out, and the carbon paper on the surface is polished with a grinder, and finally a tungsten-copper connection material with improved tungsten-copper interface bonding state by an internal oxidation-reduction process is obtained.

[0056] Example 3

[0057] The method for preparing the tungsten copper connection material in this embodiment is as follows:

[0058] Step 1: Internal oxidation of tungsten block:

[0059] For the surface treatment of the tungsten block, put the tungsten block into a tube furnace and perform internal oxidation treatment under high temperature in an oxygen atmosphere. Gradually raise the temperature to 700°C and keep it for 12 hours. After taking it out, remove the oxide added on the surface to obtain a tungsten block with surface oxidation.

[0060] Step 2: Preparation of copper powder by mechanical alloying:

[0061] Put the copper powder into a planetary ball mill, set the parameters of the ball mill to 500r / min, the ball milling time to 24h, the ball-to-material ratio to 7:3, and take it out after mechanical alloying.

[0062] Step 3: Hydrogen atmosphere reduction:

[0063] The surface oxidized tungsten block and the copper powder obtained by mechanical alloying are placed in a tubular furnace and separated from each other. The heating rate is adjusted to 5°C / min, the calcination temperature is 600°C, the insulation time is 8h, the temperature is increased by hydrogen, and the reduced copper powder and the reduced tungsten block with a rough surface and no impurity oxide are obtained after a period of insulation.

[0064] Step 4: Sintering and densification of tungsten copper connection materials:

[0065] The rough-surfaced reduced tungsten block and reduced copper powder of step three are subjected to spark plasma sintering, the internally oxidized and reduced tungsten block is loaded into a sintering mold, mechanically alloyed copper powder reduced in hydrogen atmosphere is added to the surface of the rough porous structure of the tungsten block, the mold wall and the powder are isolated by carbon paper, and the block is placed in a spark plasma sintering furnace, and the sintering furnace is evacuated; the initial pressure is set to 10 MPa, and sintering is started, and the temperature is increased from room temperature to 600°C and kept warm for 5 minutes; the temperature is then increased to 900°C and kept warm for 5 minutes, and during the heating process, the sintering pressure is manually increased to 50 MPa, and the heating rate is 100°C / min; after the insulation is completed, the block is cooled with the furnace, the product is taken out, and the carbon paper on the surface is polished with a grinder, and finally a tungsten-copper connection material with improved tungsten-copper interface bonding state by an internal oxidation-reduction process is obtained.

[0066] Comparative Example 1

[0067] The tungsten-copper connecting material prepared in this comparative example uses tungsten block as raw material, and the copper powder that has been mechanically alloyed is densified by spark plasma sintering to achieve the bonding between tungsten and copper.

[0068] The method for preparing the tungsten copper connecting material in this comparative example is as follows:

[0069] Step 1: Preparation of copper powder by mechanical alloying:

[0070] Put the copper powder into a planetary ball mill, set the parameters of the ball mill to 500r / min, the ball milling time to 24h, the ball-to-material ratio to 7:3, and take it out after mechanical alloying.

[0071] Step 2: Hydrogen atmosphere reduction:

[0072] The copper powder obtained by mechanical alloying in step 1 is placed in a tubular furnace and separated from each other. The heating rate is adjusted to 5°C / min, the calcination temperature is 600°C, the insulation time is 8h, the temperature is increased by hydrogen, and the powder is taken out after insulation for a period of time to obtain reduced mechanical alloying copper powder without impurities.

[0073] Step 3: Sintering and densification of tungsten copper connection materials:

[0074] The untreated tungsten block and the mechanically alloyed copper powder reduced in step 2 are subjected to spark plasma sintering, the tungsten block is loaded into a sintering mold, the mechanically alloyed copper powder reduced in hydrogen atmosphere is added to the surface of the tungsten block, the mold wall and the powder are isolated with carbon paper, and the block is placed in a spark plasma sintering furnace, and the sintering furnace is evacuated; the initial pressure is set to 10 MPa, and sintering is started, and the temperature is raised from room temperature to 600°C and kept warm for 5 minutes; the temperature is then raised to 900°C and kept warm for 5 minutes, and during the heating process, the pressure is manually increased to a sintering pressure of 50 MPa, and the heating rate is 100°C / min; after the insulation is completed, the block is cooled with the furnace, the product is taken out, and the carbon paper on the surface is polished with a grinder, and finally a tungsten-copper connecting material without surface treatment is obtained.

[0075] Table 1. Relevant properties of tungsten-copper connecting materials prepared in the embodiments of the present invention and the comparative examples

[0076]

[0077] From the performance difference between the examples and the comparative examples in Table 1, it can be seen that the internal oxidation reduction process can significantly increase the roughness of the bonding surface, improve the density of the connection material, and improve the thermal properties to a certain extent. At the same time, the comparison between the examples shows that different oxygen sources in the internal oxidation process bring different enhancement effects. In general, the oxygen source Cu used in Example 1 2 O works best.

[0078] Depend on Figure 2 It can be seen that the inner redox tungsten surface has greater roughness and porosity, providing better bonding pores.

[0079] Depend on Figure 3 It can be seen that the coverage depth of the surface porous structure is about 20 μm, which provides good space for copper infiltration.

[0080] Depend on Figure 4 It can be seen that the tungsten-copper connection interface has a clean connection interface and mutually twisted interdiffusion layers, which can provide better bonding strength.

[0081] Depend on Figure 5 It can be seen that the connection interface has dimples and holes where tungsten and copper penetrate each other, and has a certain degree of connectivity.

[0082] Depend on Figure 6 It can be seen that the internal redox process can significantly improve the bonding strength of the tungsten-copper connection interface.

[0083] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for improving the tungsten-copper connection interface based on internal oxidation and hydrogen reduction process, characterized in that: The tungsten block is placed in a tube furnace, and oxides are added to the surface or internal oxidation treatment is performed at high temperature in an oxygen atmosphere to generate a nano-oxide porous structure on the surface and increase the surface roughness. Subsequently, a hydrogen atmosphere is used to reduce and remove surface oxide impurities while retaining surface pores. Finally, the surface-treated tungsten block is combined with copper powder prepared by mechanical alloying and reduced in a hydrogen atmosphere to achieve effective bonding between tungsten and copper through spark plasma sintering.

2. The method according to claim 1, characterized in that The specific steps include: Step 1: Internal oxidation of tungsten block: For surface treatment of tungsten block, put the tungsten block into a tube furnace, add oxide on the surface or use oxygen atmosphere, heat up and keep warm for a period of time, take it out and remove the oxide added on the surface to obtain the tungsten block with surface oxidation; Step 2: Preparation of copper powder by mechanical alloying: Put the copper powder into a planetary ball mill, set the parameters for mechanical alloying for a period of time, and then take it out; Step 3: Hydrogen atmosphere reduction: The obtained surface oxidized tungsten block and the copper powder obtained by mechanical alloying are placed in a tube furnace and separated from each other, the parameters are adjusted, hydrogen is passed to increase the temperature, and the furnace is taken out after being kept warm for a period of time to obtain reduced copper powder and reduced tungsten blocks with rough surfaces and no impurity oxides; Step 4: Sintering and densification of tungsten copper connection materials: The rough-surfaced reduced tungsten block and reduced copper powder obtained in step three are subjected to spark plasma sintering to finally obtain a tungsten-copper connection material in which the tungsten-copper interface bonding state is improved by an internal oxidation-reduction process.

3. The method according to claim 2, characterized in that The oxide used in the step 1 is Cu2O or CuO.

4. The method according to claim 2, characterized in that In the step 1, the temperature in the tube furnace is 650-800° C., the insulation time is 12 hours, and the mass ratio of the added oxide to the tungsten block is 4:

1.

5. The method according to claim 2, characterized in that The parameters of the planetary ball mill in step 2 are 500 r / min, the ball milling time is 24 h, and the ball-to-material ratio is 7:

3.

6. The method according to claim 2, characterized in that The calcination reduction parameters of the tubular furnace in step 3 are: the atmosphere used is an Ar-H2 mixed gas with a H2 content of 10%, the heating rate is 5°C / min, the calcination temperature is 600°C, and the insulation time is 8h.

7. The method according to claim 2, characterized in that The specific steps of sintering densification in step 4 are: The internally oxidized and reduced tungsten block was placed in a sintering mold, and mechanically alloyed copper powder treated with hydrogen atmosphere reduction was added to the rough porous surface of the tungsten block. The mold wall and the powder were isolated with carbon paper, and the block was placed in a discharge plasma sintering furnace. The sintering furnace was evacuated. The initial pressure was set to 10 MPa, and sintering was started. The temperature was raised from room temperature to 600°C and kept at this temperature for 5 minutes. The temperature was then raised to 900°C and kept at this temperature for 5 minutes. During the heating process, the pressure was manually increased to a sintering pressure of 50 MPa, and the heating rate was 100°C / min. After the insulation was completed, the furnace was cooled, the product was taken out, and the carbon paper on the surface was polished with a grinder to finally obtain a tungsten-copper connection material with improved tungsten-copper interface bonding state.

8. Use of the tungsten-copper connecting material prepared by the method according to any one of claims 1 to 7 as a composite module in a nuclear fusion reactor.

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