A method for connecting tungsten-copper modules to support legs in a nuclear fusion divertor device

Abstract

This invention belongs to the field of key component manufacturing technology for nuclear fusion devices, specifically relating to a method for connecting a tungsten-copper module and a support leg in a nuclear fusion divertor device. The method includes the following steps: preparing a tungsten block with a specific pore structure, and machining the end face connecting it to the support leg and the through-holes in the inner wall of the perforated tungsten block to a roughness Ra < 5.2 μm; based on the thermal expansion characteristics of the support leg, accurately calculating and preparing a graphite box of specially sized dimensions to ensure it will not crack due to internal components during subsequent high-temperature processes; sequentially assembling the perforated tungsten block, pure copper sheet, and support leg into the graphite box; connecting them through a cladding process, and precisely controlling the cladding holding time to ensure sufficient wetting and spreading of the molten copper while preventing interface performance degradation due to excessive time. This method effectively achieves a dense metallurgical bond between tungsten and the support leg, significantly improving the joint strength and high-temperature service reliability.

Description

Technical Field

[0001] This invention belongs to the field of manufacturing technology of key components for nuclear fusion devices, specifically relating to a method for connecting a tungsten-copper module and a support leg in a nuclear fusion divertor device. Background Technology

[0002] In magnetic confinement fusion devices (such as ITER and CFETR), the divertor is a core component directly exposed to high-temperature plasma. Its target plate needs to withstand extremely high steady-state and transient thermal loads, intense particle bombardment, and neutron irradiation. Tungsten, due to its high melting point, low sputtering rate, and good high-temperature strength, is chosen as the target plate material for divertors. It is often used in the form of tungsten-copper composites (such as W / Cu) to utilize the high thermal conductivity of copper to enhance heat dissipation. For example, through-holes are made in the tungsten block, and a copper layer is placed on the inner wall of the through-holes to form a tungsten-copper module. Support legs are connected to the side walls of the tungsten-copper module, providing structural support. However, there are significant differences in physical properties between tungsten and the support leg materials, especially in their coefficients of thermal expansion (CTE) (tungsten approximately 4.5 × 10⁻⁶). -6 / K, Inconel 625 approximately 16.5 × 10 -6 / K~17.5×10 -6 / K, 316L and 316L(N) are approximately 19 × 10 -6 / K~21×10 -6 The two have poor miscibility, and direct bonding will generate huge thermal stress at the interface, leading to cracking or extremely low bonding strength.

[0003] In existing technologies, brazing or diffusion welding are commonly used for connection. However, ordinary brazed joints lack sufficient high-temperature performance, making them unsuitable for use in harsh environments; while direct diffusion welding struggles to achieve high-quality connections due to material incompatibility. Using copper or its alloys as an intermediate layer is a feasible approach, but under conventional processes, issues such as the wettability of copper to tungsten and support leg materials, interfacial reaction control, and stress matching during the connection process remain unresolved, resulting in low joint qualification rates and unstable performance. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for connecting a tungsten-copper module and a support leg in a nuclear fusion divertor device. This invention enables the connection between the tungsten in the tungsten-copper module and the support leg material (316L / 316L(N) / Inconel 625 alloy) to achieve high interfacial bonding strength, low residual stress, and good process reliability, making it suitable for widespread application.

[0005] The present invention specifically adopts the following technical solution: This invention provides a method for connecting a tungsten-copper module to a support leg in a nuclear fusion divertor device, comprising the following steps: (1) Machining is performed on the tungsten blocks to be joined to roughen the surfaces to be joined and the inner walls of the through holes.

[0006] It should be noted that in this invention, the surfaces of the tungsten blocks to be joined are machined to increase the roughness of the joining surfaces within a certain range, thereby creating a mechanical interlocking effect and preventing interfacial shear failure. Preferably, the roughness Ra < 5.2 μm, more preferably 0.4 μm to 5.2 μm. A certain degree of roughness can improve the connection strength, but excessive roughness will lead to excessive stress on the joining surfaces, thus reducing the connection strength. The connection strength decreases linearly when the roughness is higher than 5.2. Therefore, the roughness of the surfaces of the tungsten blocks to be joined is 0.4 μm to 5.2 μm, and the roughness of the inner wall of the through hole is 0.4 μm to 5.2 μm. The roughness of the support legs is not required.

[0007] In addition, for divertor target plate products, a through-hole is opened in the middle, and a copper layer is set on the inner wall of the through-hole. This through-hole is used to set up a cooling pipe. The heat generated on the tungsten target plate is quickly conducted to the cooling medium in the cooling pipe through the copper layer, realizing the rapid cooling of the tungsten target plate. In the process of connecting the tungsten block and the support leg, this invention not only realizes the connection between the tungsten block and the support leg, but also, in the subsequent heat treatment process, the copper melts and simultaneously wets and spreads on the inner wall of the through-hole of the tungsten block, simultaneously realizing the setting of a copper layer on the inner wall of the through-hole, thus obtaining a tungsten-copper module. In order to ensure that the copper effectively wets the connection surface and the through-hole after melting, a mold is required for connection to ensure the accuracy of the connection and good wettability of the copper. Specifically, the mold is a graphite box mold, which includes a box body with a cavity inside. The shape of the cavity matches the shape of the component to be connected, and the size needs to be specially designed. The specific assembly requirements of the component and the mold size are as follows.

[0008] (2) The tungsten block, pure copper intermediate layer and support leg after machining are placed in the internal cavity of the graphite box mold in the order of tungsten block connecting surface, pure copper intermediate layer and support leg connecting surface to obtain the assembly component; the internal cavity size of the graphite box mold = the total size of tungsten block, pure copper intermediate layer and support leg + the safe expansion gap of support leg at the heat treatment temperature.

[0009] It should be noted that the internal cavity size of the graphite box mold should be appropriately larger than the overall size of the components. This is because the components (support leg material 316L / 316L(N) / Inconel 625 alloy) will expand during heat treatment. If the cavity size is comparable to the component size, cracking will occur during heat treatment. If the cavity size is too large, the copper molten material cannot guarantee complete wetting of the connection surfaces. Therefore, the cavity size is critical, and a safety expansion gap should be reserved to ensure that the stress on the inner wall of the graphite box is lower than its tensile strength at that temperature during heat treatment.

[0010] (3) The assembly components are heat-treated. During the heat treatment process, the pure copper intermediate layer melts and wets and spreads on the connection surface of the tungsten block and the support leg, as well as in the through hole of the tungsten block. After cooling, the metallurgical connection between the tungsten copper module and the support leg is realized.

[0011] It should be noted that the pure copper interlayer has good plasticity and can be used as a soft interlayer to absorb and buffer the stress generated during thermal cycling due to the difference in thermal expansion coefficients between tungsten and the support leg.

[0012] Preferably, the tungsten block is in a rolled state, and the grain orientation of the end face used for connection is perpendicular to the original rolling direction. It should be noted that the tungsten-copper module may fail and crack when directly irradiated with plasma. The grain orientation of the end face perpendicular to the original rolling direction will cause the failure crack to open vertically, without affecting the cracking of the tungsten-copper interface (the tungsten-copper interface is horizontal).

[0013] Preferably, the purity of the pure copper interlayer is not less than 99.9 wt.%, and the thickness is 1 mm to 1.5 mm.

[0014] Preferably, the safe expansion gap ΔL of the support leg at the heat treatment temperature is given by: ΔL = α·L0·ΔT·k, where k is a safety factor (1.25 ≤ k ≤ 1.45), L0 is the initial size of the support leg, ΔT is the difference between the heat treatment temperature and room temperature, and α is the coefficient of thermal expansion of the support leg material (316L / 316L(N) / Inconel 625 alloy). The theoretical expansion amount is multiplied by the safety factor k (1.25 ≤ k ≤ 1.45) to determine the reserved safe expansion gap, thereby ensuring that the stress on the inner wall of the graphite box is lower than its tensile strength at that process temperature.

[0015] Preferably, the heat treatment is carried out under a protective gas or vacuum atmosphere, and the heat treatment regime is as follows: heating to 1100℃~1200℃ at a rate of 5℃ / min~15℃ / min, and holding at that temperature for 15min~20min. More preferably, the protective gas is hydrogen.

[0016] Preferably, before component assembly, the tungsten block, the pure copper sheet as the intermediate layer, and the connecting surfaces of the support legs are ultrasonically cleaned and dried to remove oil and oxides.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for connecting a tungsten-copper module and a support leg in a nuclear fusion divertor device. The method involves machining a perforated tungsten block to be connected. The machined tungsten block, a pure copper intermediate layer, and the support leg are then placed in the internal cavity of a graphite box mold in the order of tungsten block connection surface, pure copper intermediate layer, and support leg connection surface, to obtain an assembly. The internal cavity size of the graphite box mold equals the total size of the tungsten block, pure copper intermediate layer, and support leg plus the safety expansion gap of the support leg at the heat treatment temperature. The assembly is then heat-treated. During heat treatment, the pure copper intermediate layer melts and wets and spreads on the connection surface of the tungsten block and support leg, as well as within the through-hole of the tungsten block. After cooling, a metallurgical bond is achieved between the tungsten-copper module and the support leg.

[0018] (1) High interface bonding strength: The present invention utilizes the cladding process during heat treatment to achieve good wetting and metallurgical bonding of copper to tungsten and support legs, realizes deep diffusion and densification, and obtains a metallurgically bonded interface.

[0019] (2) Effectively relieves thermal stress: The pure copper interlayer has good plasticity and can be used as a soft interlayer to absorb and buffer the stress generated during thermal cycling due to the difference in thermal expansion coefficients between tungsten and the support leg. At the same time, it increases the surface roughness of tungsten within a certain range, enhances the mechanical interlocking effect, and further prevents interfacial shear failure.

[0020] (3) Good process reliability: The size of the graphite box mold is designed by accurately calculating the thermal expansion, which avoids the problem of cracking due to component expansion during the cladding process. At the same time, it ensures that the copper melts and completely wets the connection surface, thus ensuring the stability and repeatability of the process.

[0021] (4) Excellent joint performance: The connecting components prepared by this method can work stably under high temperature and high stress environment, and are particularly suitable for the nuclear fusion field where there are extreme requirements for connection reliability and high temperature performance. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the assembly of the components in the graphite box.

[0023] Figure 2 This is a schematic diagram of the structure of a perforated tungsten block.

[0024] Figure 3 Metallographic image of the connection interface of the tungsten copper module-Inconel 625 alloy support leg component after low-cycle fatigue in Example 1.

[0025] Figure 4 This is a photograph of the tungsten copper module - Inconel 625 alloy support leg component after low-cycle fatigue in Example 1.

[0026] Figure 5 This is a metallographic image of the connection interface of the tungsten copper module-316L alloy support leg component after low-cycle fatigue in Example 2.

[0027] Figure 6 The image shows a tungsten copper module – an Inconel 625 alloy support leg component – ​​after low-cycle fatigue testing, as shown in Comparative Example 1.

[0028] Figure 7 For comparison, here is a photograph of the tungsten copper module-316L alloy support leg component after it has been removed from the graphite mold but before machining.

[0029] Figure 8 The photo shows the actual tungsten copper module-316L alloy support leg component after low-cycle fatigue, which is a comparative example. Detailed Implementation

[0030] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below with reference to specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention. Unless otherwise specified, the experimental methods and detection methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials described are commercially available.

[0031] Example 1 Industrial pure tungsten is connected to Inconel 625 alloy support legs. Figure 1 This is a schematic diagram of the assembly of the components in the graphite box. Figure 2 This is a top view of the perforated tungsten block. In the figure, 1 is a graphite box, 2 is the tungsten block, 21 is a through hole, 3 is a pure copper sheet, and 4 is a support leg. In this embodiment, the support leg 4 is made of Inconel 625 alloy. The tungsten block 2 has dimensions of 32mm×26mm×13.5mm and a through hole 21 with a diameter of φ16mm×13.5mm on its 32mm×26mm surface. The Inconel 625 alloy support leg has dimensions of 32mm×16mm×14mm.

[0032] This embodiment provides a method for connecting a tungsten copper module to an Inconel 625 alloy support leg, including the following steps: Step 1: Machin the tungsten block to be connected by drilling to achieve a surface roughness Ra of 5.1 μm on the end face connecting to the Inconel 625 alloy support leg, and a surface roughness Ra of 5.1 μm on the inner wall of the through hole. A high-purity oxygen-free copper sheet (99.95% purity, 1 mm thickness) is selected as the intermediate layer.

[0033] Step 2: Accurately measure and calculate the linear thermal expansion of Inconel 625 alloy at 1120℃ (with its CTE = 16.5 × 10⁻⁶). -6 / K (calculated). Theoretical thermal expansion = α·L0·ΔT, the theoretical linear thermal expansion of Inconel 625 alloy at 1120℃ is calculated to be 0.57mm (length) and 0.28mm (width).

[0034] Step 3: Based on the design requirements, a safety factor k of 1.35 is chosen. Using this data as a basis, the theoretical thermal expansion is multiplied by the safety factor to obtain the reserved safety expansion gap. The length and width dimensions of the internal cavity of the graphite box mold are obtained by adding the total dimensions of the tungsten block, the pure copper intermediate layer, and the support legs to the safety expansion gap. The inner cavity length and width of the graphite box are designed according to these dimensions to ensure that the stress on the inner wall of the graphite box is lower than its tensile strength at this process temperature, thus ensuring safety. Subsequently, this specially made graphite box is processed using high-purity graphite.

[0035] Step 4: Clean the connecting surfaces of all components (tungsten block, pure copper sheet, Inconel 625 support leg) ultrasonically with acetone and alcohol, then dry. Figure 1 In the order shown, tungsten block 2, pure copper sheet 3, and support leg 4 are placed into the inner cavity of graphite box 1 to ensure that the tungsten, Inconel 625 alloy support leg, and tungsten block through hole are completely submerged after melting.

[0036] Step 5: Place the assembled graphite box into a heating furnace and heat it to 1120°C at a rate of 10°C / min under a hydrogen atmosphere, holding it at that temperature for 15 minutes. During this process, the pure copper sheet completely melts and spreads wetly at the interface between the tungsten block and the Inconel 625 support leg, as well as in the through-holes of the tungsten block. Figure 1 The number 31 indicates that the pure copper sheet is melted and wetted into the through hole, and then cooled with the furnace. This yields a well-connected tungsten copper module - the Inconel 625 alloy support leg component.

[0037] Step 6: According to the design drawings, use a milling machine to remove the excess copper, use a grinding machine to grind it to the required thickness, and use wire cutting to cut out the dimensions to obtain the tungsten copper module - Inconel 625 alloy support leg component of Example 1.

[0038] Table 1 shows the low-cycle fatigue test and mechanical test data of the tungsten copper module - Inconel 625 alloy support leg component. Figure 4 This is a photograph of the tungsten copper module - Inconel 625 alloy support leg component after low-cycle fatigue in Example 1. Figure 3 Metallographic image of the connection interface of the tungsten copper module-Inconel 625 alloy support leg component after low-cycle fatigue. The interface is tightly connected and free of defects such as pores and cracks.

[0039] Table 1. Low-cycle fatigue and mechanical test data of the tungsten copper module - Inconel 625 alloy support leg component. Example 2 The industrial pure tungsten is connected to the 316L alloy support leg. The tungsten block has dimensions of 32mm×30mm×14mm and a through hole of φ20mm×14mm on the 32mm×30mm surface of the tungsten block. The 316L alloy support leg has dimensions of 32mm×16mm×14mm.

[0040] This embodiment provides a method for connecting a tungsten copper module with a 316L alloy support leg, including the following steps: Step 1: Machin the tungsten block to be connected by drilling to achieve a surface roughness Ra of 1.2 μm on the end face connecting to the 316L alloy support leg, and a surface roughness Ra of 1.2 μm on the inner wall of the through hole. A high-purity oxygen-free copper sheet (99.95% purity, 1 mm thickness) is selected as the intermediate layer.

[0041] Step 2: Accurately measure and calculate the linear thermal expansion of 316L alloy at 1180℃ (using its CTE = 19.5 × 10⁻⁶). -6 / K (calculated). Theoretical thermal expansion = α·L0·ΔT, the linear thermal expansion of 316L alloy at 1180℃ is 0.67mm (length) and 0.33mm (width).

[0042] Step 3: Based on the design requirements, a safety factor k of 1.40 is chosen. Using this data as a basis, the theoretical thermal expansion is multiplied by the safety factor to obtain the reserved safety expansion gap. The length and width dimensions of the internal cavity of the graphite box mold are then obtained based on the total dimensions of the tungsten block, the pure copper intermediate layer, and the support legs, plus the safety expansion gap. The internal dimensions of the graphite box cavity are designed according to these dimensions to ensure safety. Subsequently, the specially made graphite box is manufactured using high-purity graphite.

[0043] Step 4: Ultrasonically clean and dry the connecting surfaces of all components (tungsten block, pure copper sheet, 316L support leg) with acetone and alcohol. Figure 1 As shown in the sequence, place the tungsten block, pure copper sheet, and 316L support leg into the inner cavity of the graphite box in order, ensuring that the tungsten, 316L alloy support leg, and tungsten block through hole are completely submerged after melting.

[0044] Step 5: Place the assembled graphite box into a heating furnace and heat it to 1180°C at a rate of 10°C / min under a hydrogen atmosphere, holding it at that temperature for 15 minutes. During this process, the pure copper sheet completely melts and spreads onto the interface between the tungsten block and the 316L support leg, as well as within the through-holes of the tungsten block. It then cools with the furnace. This yields a perfectly connected tungsten-copper module-316L alloy support leg component.

[0045] Step 6: According to the design drawings, use a milling machine to remove the excess copper, use a grinding machine to grind it to the required thickness, and use wire cutting to cut out the dimensions to obtain the tungsten copper module-316L alloy support leg component of Example 2.

[0046] Table 2 shows the low-cycle fatigue test and mechanical test results of the tungsten copper module-316L alloy support leg component. Figure 5 The metallographic image shows the connection interface of the tungsten copper module-316L alloy support leg component after low-cycle fatigue. The interface is tightly connected and free from defects such as pores and cracks.

[0047] Table 2 Low-cycle fatigue test and mechanical test data of tungsten copper module-316L alloy support leg components Comparative Example 1 The industrial pure tungsten is connected to the Inconel 625 alloy support leg. The tungsten block has dimensions of 32mm×26mm×13.5mm and a through hole of φ16mm×13.5mm on the 32mm×26mm surface of the tungsten block. The Inconel 625 alloy support leg has dimensions of 32mm×16mm×14mm.

[0048] This comparative example provides a method for fabricating a connection between a tungsten copper module and an Inconel 625 alloy support leg, comprising the following steps: Step 1: Machin the tungsten block to be connected by drilling to achieve a surface roughness Ra of 6.3 μm on the end face connecting to the Inconel 625 alloy support leg, and a surface roughness Ra of 6.3 μm on the inner wall of the through hole. A high-purity oxygen-free copper sheet (99.95% purity, 1 mm thickness) is selected as the intermediate layer.

[0049] Step 2: Accurately measure and calculate the linear thermal expansion of Inconel 625 alloy at 1080℃ (with its CTE = 16.5 × 10⁻⁶). -6 / K). The theoretical linear thermal expansion of Inconel 625 alloy at 1080℃ is 0.57mm (length) and 0.28mm (width).

[0050] Step 3: Based on the design requirements, a safety factor k of 1.35 is chosen. Using this data as a basis, the theoretical thermal expansion is multiplied by the safety factor to obtain the reserved safety expansion gap. The length and width dimensions of the internal cavity of the graphite box mold are then obtained by adding the total dimensions of the tungsten block, the pure copper intermediate layer, and the support legs to the safety expansion gap. The internal dimensions of the graphite box are designed according to these dimensions to ensure safety. Subsequently, the specially made graphite box is manufactured using high-purity graphite.

[0051] Step 4: Clean the connecting surfaces of all components (tungsten block, pure copper sheet, Inconel 625 support leg) ultrasonically with acetone and alcohol, then dry. Figure 1As shown in the order, place the tungsten block, pure copper sheet, and Inconel 625 support leg into the inner cavity of the graphite box, ensuring that the tungsten, Inconel 625 alloy support leg, and tungsten block through hole are completely submerged after melting.

[0052] Step 5: Place the assembled graphite box into the heating furnace and heat it to 1080°C at a rate of 10°C / min under a hydrogen atmosphere. Hold the temperature for 40 minutes, and then cool it with the furnace.

[0053] Step 6: According to the design drawings, use a milling machine to remove the excess copper, use a grinding machine to grind it to the required thickness, and use wire cutting to cut out the dimensions to obtain the tungsten copper module - Inconel 625 alloy support leg component of Comparative Example 1.

[0054] Table 3 shows the low-cycle fatigue test and mechanical test data of the tungsten copper module-Inconel 625 alloy support leg component. Figure 6 This is a photograph of the Inconel 625 alloy support leg component of the tungsten copper module after low-cycle fatigue, showing fracture after only 2653 cycles. Its mechanical strength is only 45 MPa.

[0055] Table 3 Low-cycle fatigue and mechanical test data of the tungsten copper module - Inconel 625 alloy support leg component. As shown by the data in Comparative Example 1, the increased roughness and changes in temperature and holding time in Comparative Example 1 reduce the bonding performance. Therefore, it is necessary to control the machining of the tungsten block end face to a roughness Ra of 0.4~5.2μm and precisely control the cladding holding time to ensure sufficient wetting and spreading of the copper liquid while preventing the interface performance from deteriorating due to excessive time. A comparison with Comparative Example 1 shows that the method of this invention effectively achieves a dense metallurgical bond between tungsten and the support leg, significantly improving the bonding strength and high-temperature service reliability of the joint.

[0056] Comparative Example 2 The industrial pure tungsten is connected to the 316L alloy support leg. The tungsten block has dimensions of 32mm×30mm×14mm and a through hole of φ20mm×14mm on the 32mm×30mm surface of the tungsten block. The 316L alloy support leg has dimensions of 32mm×16mm×14mm.

[0057] This embodiment provides a method for connecting a tungsten copper module with a 316L alloy support leg, including the following steps: Step 1: Machin the tungsten block to be connected by drilling to achieve a surface roughness Ra of 5.1μm on the end face connecting to the 316L alloy support leg, and a surface roughness Ra of 5.1μm on the inner wall of the through hole. A high-purity oxygen-free copper sheet (99.95% purity, 1mm thickness) is selected as the intermediate layer.

[0058] Step 2: Accurately measure and calculate the linear thermal expansion of 316L alloy at 1180℃ (based on its CTE = 19.5 × 10⁻⁶ / K). The theoretical thermal expansion = α·L₀·ΔT. The linear thermal expansion of 316L alloy at 1180℃ is 0.67 mm (length) and 0.33 mm (width).

[0059] Step 3: Based on the design requirements, a safety factor k of 1.60 is chosen. Using this data as a basis, the theoretical thermal expansion is multiplied by the safety factor to obtain the reserved safety expansion gap. The length and width dimensions of the internal cavity of the graphite box mold are then obtained by adding the total dimensions of the tungsten block, the pure copper intermediate layer, and the support legs to the safety expansion gap. The internal cavity length and width of the graphite box are designed according to these dimensions to ensure safety. Subsequently, the specially made graphite box is manufactured using high-purity graphite.

[0060] Step 4: Ultrasonically clean and dry the connecting surfaces of all components (tungsten block, pure copper sheet, 316L support leg) with acetone and alcohol. Figure 1 As shown in the sequence, place the tungsten block, pure copper sheet, and 316L support leg into the inner cavity of the graphite box in order, ensuring that the tungsten, 316L alloy support leg, and tungsten block through hole are completely submerged after melting.

[0061] Step 5: Place the assembled graphite box into the heating furnace and heat it to 1180°C at a rate of 10°C / min under a hydrogen atmosphere. Hold the temperature for 15 minutes and then cool it with the furnace.

[0062] Step 6: According to the design drawings, use a milling machine to remove the excess copper, use a grinding machine to grind it to the required thickness, and use wire cutting to cut out the dimensions to obtain the tungsten copper module-316L alloy support leg component.

[0063] Figure 7 The image shown is of the tungsten-copper module-316L alloy support leg component in Comparative Example 2, taken from the graphite mold but not yet machined. Due to the excessively large size of the graphite cavity, the molten copper did not completely wet the connecting surface, and the copper adhered to the graphite, causing wear and tear on the graphite mold and increasing costs. Table 4 shows the low-cycle fatigue test and mechanical test data for the tungsten-copper module-316L alloy support leg component. Figure 8 The image shown is of a tungsten copper module-316L alloy support leg component after low-cycle fatigue, as shown in Comparative Example 2. It fractured after only 263 low-cycle fatigue cycles, with a mechanical strength of only 30.33 MPa.

[0064] Table 4 Low-cycle fatigue test and mechanical test data of tungsten copper module-316L alloy support leg components As shown in Comparative Example 2, the present invention designs the internal cavity size of the graphite box mold to be the total size of the tungsten block, the pure copper intermediate layer, and the support leg, plus the safe expansion gap of the support leg at the heat treatment temperature. This ensures sufficient wetting and spreading of the molten copper while preventing the degradation of interface properties and wear of the graphite mold due to excessively large graphite cavity size. This method effectively achieves a dense metallurgical bond between tungsten and the support leg, significantly improving the joint strength and high-temperature service reliability.

[0065] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, it is intended to include any modifications and variations that fall within the scope of the claims and their equivalents.

Claims

1. A method for connecting a tungsten-copper module and a support leg in a nuclear fusion divertor device, characterized in that, Includes the following steps: The tungsten blocks to be joined are machined to roughen the surfaces to be joined and the inner walls of the through holes. The machined tungsten block, pure copper intermediate layer, and support leg are placed in the internal cavity of the graphite box mold in the order of tungsten block connecting surface, pure copper intermediate layer, and support leg connecting surface to obtain the assembly component; the internal cavity size of the graphite box mold = the total size of the tungsten block, pure copper intermediate layer, and support leg + the safe expansion gap of the support leg at the heat treatment temperature; The assembly components undergo heat treatment. During the heat treatment process, the pure copper intermediate layer melts and wets and spreads on the connection surface between the tungsten block and the support leg, as well as inside the through hole of the tungsten block. After cooling, the tungsten copper module and the support leg are metallurgically bonded together.

2. The method for connecting the tungsten-copper module and the support leg in the nuclear fusion divertor device according to claim 1, characterized in that, The tungsten block is in a rolled state, and the grain orientation of the end face used for connection is perpendicular to the original rolling direction.

3. The method for connecting the tungsten-copper module and the support leg in the nuclear fusion divertor device according to claim 1, characterized in that, The surface roughness of the tungsten block to be joined is 0.4μm~5.2μm, and the roughness of the inner wall of the through hole of the tungsten block is 0.4μm~5.2μm.

4. The method for connecting the tungsten-copper module and the support leg in the nuclear fusion divertor device according to claim 1, characterized in that, The purity of the pure copper intermediate layer is not less than 99.9 wt.%, and the thickness is 1mm~1.5mm.

5. The method for connecting the tungsten-copper module and the support leg in the nuclear fusion divertor device according to claim 1, characterized in that, The safe expansion gap of the support leg at the heat treatment temperature is ΔL = α·L0·ΔT·k, where k is the safety factor, 1.25 ≤ k ≤ 1.45; L0 is the initial size of the support leg; ΔT is the difference between the heat treatment temperature and the room temperature; and α is the coefficient of thermal expansion of the support leg material.

6. The method for connecting the tungsten-copper module and the support leg in the nuclear fusion divertor device according to claim 1, characterized in that, During heat treatment, the process is carried out under a protective gas or vacuum atmosphere. The heat treatment regime is as follows: the temperature is increased to 1100℃~1200℃ at a rate of 5℃ / min~15℃ / min, and held for 15min~20min.

7. The method for connecting the tungsten-copper module and the support leg in the nuclear fusion divertor device according to claim 6, characterized in that, The protective gas is hydrogen.

8. The method for connecting the tungsten-copper module and the support leg in the nuclear fusion divertor device according to claim 1, characterized in that, Before component assembly, the tungsten block, the pure copper sheet as the intermediate layer, and the connecting surfaces of the support legs are ultrasonically cleaned and dried to remove oil and oxides.

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