A pressureless preparation method of capillary pore structure based on tungsten-based medium-entropy material applied to a deflector

Abstract

The application relates to a pressureless preparation method of a capillary pore structure based on tungsten-based medium-entropy material applied to a filter, and belongs to the technical field of fusion reactor filters. A three-dimensional model is constructed according to the capillary pore structure; W, Cu, Cr and V four kinds of metal powders are added into a first ball mill jar, Cu and Cr two kinds of metal powders are added into a second ball mill jar, the two ball mill jars are mixed after ball milling, and tungsten-based medium-entropy alloy powder is obtained; paraffin and stearic acid are fully mixed, and then heated to a molten state to obtain a paraffin-based bonding agent; the medium-entropy alloy powder is preheated and added into the paraffin-based bonding agent to obtain a metal slurry; the paraffin pre-prepared framework is preheated, the metal slurry is injected, a hot-pressing die is used, and a tungsten-based medium-entropy alloy pore structure blank is obtained after cooling; and then, degreasing and sintering are carried out, so that the capillary pore structure based on the tungsten-based medium-entropy material is obtained. The capillary pore structure prepared by the pressureless preparation method has better structural bearing capacity and impact resistance.

Description

Technical Field

[0001] This invention belongs to the field of fusion reactor divertor components, and more specifically, relates to a pressureless preparation method for capillary channel structures based on tungsten-based medium-entropy materials applied to divertors. Background Technology

[0002] The interaction between plasma and plasma-facing materials directly determines three key indicators of fusion reactor core plasma performance, material service life, and deuterium-tritium self-sustaining cycle. This has been listed as a core research focus in the latest implementation plan for the China Fusion Engineering Test Reactor (CFETR). The liquid-solid composite configuration refers to the deposition of a low-melting-point metal onto a high-melting-point solid metal substrate. Utilizing the high volatilization and sputtering rates of the liquid metal, a lithium vapor cloud is formed near the target plate. Through physical processes such as collision, radiation, and recombination, plasma energy is effectively dissipated, significantly reducing the thermal load on the first wall components. Compared to tin, lithium, with its lower atomic number, has better compatibility with tokamak devices, and its higher sputtering rate provides superior thermal shielding. This makes the liquid-solid composite configuration based on liquid lithium an ideal choice for divertors and first wall components, with key advantages including: complete avoidance of surface thermal stress accumulation and neutron irradiation damage; and a significantly increased thermal load capacity to 50 MW / m². 2 The above features include: self-healing capabilities to extend service life; and effective reduction of boundary particle recirculation rate, which is beneficial for discharge control.

[0003] Material compatibility is a primary consideration when designing liquid-solid composite components. For fusion reactor divertors and first-wall components, the corrosion and wetting characteristics of lithium and tungsten-based alloys / heat sink materials, as well as the interfacial bonding performance between tungsten-based materials and heat sink materials, are fundamental requirements for ensuring the normal operation of the target plate components. Experimental studies have confirmed that tungsten-based materials, as film flow substrates, not only possess excellent resistance to lithium corrosion, but their high melting point also effectively prevents problems such as discharge instability and droplet inhomogeneity; while traditional CuCrZr heat sink materials and tungsten-based alloy connectors can meet the requirements of 20MW / m 2 Thermal load requirements.

[0004] Structural design is the second key consideration for liquid-solid composite components. Under the constraints of extremely strong magnetic fields and the unique flow characteristics of liquid lithium, capillary porous structures (CPS) have proven to be the optimal solution. Early planar membrane flow structures, while validating tokamak discharge compatibility, could not overcome magnetohydrodynamic effects and droplet splashing problems. Improved densely woven metal mesh structures demonstrated suppression of magnetohydrodynamic effects in linear device experiments, but still could not achieve stable lithium replenishment. CPS structures utilize capillary forces to achieve stable surface lithium replenishment. Through the synergistic effect of precisely arranged capillary channels and surface micro / nano structures, uniform coverage of liquid lithium is ensured while effectively suppressing droplet splashing.

[0005] The fabrication of complex CPS structures primarily relies on 3D printing technology, an additive manufacturing method that uses high-energy laser or electron beam to melt fine powder layer by layer. For tungsten-based materials, improving density, reducing crack formation, and precisely controlling molding accuracy remain key technical challenges. Due to the high surface tension of molten tungsten-based materials, their poor spreading performance and susceptibility to spheroidization effects often result in insufficient density and inadequate spatial resolution in directly 3D-printed tungsten-based materials.

[0006] Patent CN112795828A discloses a method for preparing tantalum-tungsten alloy and thin-walled plates for 3D printing. The method involves preparing uniform spherical powder using a solid-solid mixing process, followed by laser selective melting to obtain thin-walled tantalum-tungsten alloy parts. While the alloy produced by this method exhibits good density, toughness, and excellent crack resistance, it suffers from significant drawbacks in practical applications: the thickness of the thin plate is difficult to control precisely, inevitably resulting in random or irregular surface undulations. This not only reduces the mechanical strength of the structural components but also leads to poor process repeatability and controllability, severely restricting the spatial optimization design of tungsten-based material CPS structures. Furthermore, the preparation of spherical tungsten powder is challenging, making it difficult to guarantee the economic viability and feasibility of mass production.

[0007] Patent CN113102753A discloses a debinding and sintering method for indirect 3D printing of tungsten-based alloy parts. This method places a tungsten-based alloy preform, formed by extruding metal powder, into an atmosphere furnace, purging it with a protective or reducing atmosphere throughout the process. First, a multi-step, slow heating process is used for debinding, followed by a slow heating to the sintering temperature range for sintering, and finally, slow cooling to room temperature to obtain a high-performance tungsten-based alloy. However, the tungsten material parts formed by this method have relatively simple structures, and the 93W metal material used is insufficient to meet the forming requirements of complex CPS structures. Summary of the Invention

[0008] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a pressureless preparation method for capillary channel structures based on tungsten-based medium-entropy materials for use in divertors. First, a paraffin preform with capillary channel voids is prepared. Then, a metal slurry containing tungsten-based medium-entropy alloy powder is hot-pressed into a die, followed by debinding and sintering. This invention avoids difficulties in filling the mold with molten metal and defects such as shrinkage cavities or cracks that may occur during solidification. The resulting capillary channel structure transmits stress uniformly under load, avoiding stress concentration and thus exhibiting better structural load-bearing capacity and impact resistance.

[0009] According to the present invention, a pressureless preparation method for a capillary channel structure based on a tungsten-based medium-entropy material for use in divertors is provided, comprising the following steps:

[0010] (1) A three-dimensional model is constructed based on the capillary channel structure, which includes multiple capillary channel units arranged in a row and column periodically and a connecting layer, wherein the connecting layer is located at the bottom of the capillary channel unit; there are gaps between each capillary channel unit; any one of the capillary channel units includes a base, multiple supports located on the base and a channel module located on each support, and there are gaps between each channel module and each support; using the three-dimensional model, a mixture of paraffin wax and stearic acid is used as the molding material to prepare a paraffin wax prefabricated skeleton with capillary channel gaps;

[0011] (2) Add four metal powders, W, Cu, Cr and V, to the first ball mill jar, and add two metal powders, Cu and Cr, to the second ball mill jar. Then, ball mill the substances in the first ball mill jar and the substances in the second ball mill jar. Then mix the powders in the first ball mill jar and the second ball mill jar to obtain tungsten-based medium entropy alloy powder.

[0012] Paraffin wax and stearic acid are thoroughly mixed and then heated to a molten state to obtain a paraffin-based adhesive; the tungsten-based medium-entropy alloy powder is preheated and added to the paraffin-based adhesive to obtain a metal slurry;

[0013] (3) After preheating the paraffin preform obtained in step (1), inject the metal slurry obtained in step (2) into it, and use a hot press casting die to make the metal slurry fully fill the paraffin preform. After cooling, a tungsten-based medium-entropy alloy channel structure blank is obtained.

[0014] (4) The tungsten-based medium-entropy alloy pore structure blank obtained in step (3) is degreased and then sintered to obtain a capillary pore structure based on tungsten-based medium-entropy material.

[0015] Preferably, in step (4), the degreasing process includes two stages;

[0016] First stage: Under an inert gas atmosphere, the temperature is raised to 200-250℃ and held for 1-2 hours, then raised to 255-265℃, 275-285℃ and 295-305℃ and held for 1 hour each to remove the paraffin-based adhesive.

[0017] Second stage: Continue heating to 550-600℃ and hold for 2-3 hours in a mixed atmosphere of inert gas and hydrogen to remove the paraffin preform and reduce the oxidized metal.

[0018] Preferably, in step (4), the sintering specifically involves heating to 1500-1600℃ at a heating rate of 4-5℃ / min and holding at that temperature for 2-3 hours.

[0019] Preferably, in step (2), the ball milling speed is 250-300 rpm and the ball milling time is 12-15 h.

[0020] Preferably, in step (2), the preheating temperature of the medium entropy alloy powder is 60-80℃.

[0021] Preferably, in step (1), the paraffin preform with capillary pores is prepared by photopolymerization 3D printing technology.

[0022] Preferably, in step (2), the mass percentage of paraffin-based adhesive in the metal slurry is 10-15%.

[0023] Preferably, the gaps between each capillary channel unit and between each channel module have the same width, which is 60-100 μm.

[0024] Preferably, the height of the connecting layer is 2-2.5 mm.

[0025] Preferably, the height of the base is 2-2.5 mm.

[0026] In summary, compared with the prior art, the technical solutions conceived in this invention have the following main advantages:

[0027] (1) The present invention obtains a capillary structure by hot-pressing a metal slurry containing a tungsten-based medium-entropy alloy into a skeleton through a hot-pressing die, and then by degreasing and sintering. The preparation method provided by the present invention is different from the existing melt infiltration method. It makes full use of the good fluidity of organic substances such as paraffin in the molten state and the characteristics of cooling and solidification. The molding and forming process is completed under conditions slightly above room temperature. Compared with vacuum pressure infiltration, this method does not require heating the metal to a temperature higher than the melting point. Therefore, it does not require special high-temperature and high-pressure equipment, which not only reduces the cost, but also avoids the difficulty of filling the metal molten metal into the mold and the defects such as shrinkage cavities or cracks that may exist during the solidification process.

[0028] (2) This invention achieves integrated design and fabrication of the capillary structure by hot-pressing a metal slurry containing a tungsten-based medium-entropy alloy into a skeleton, followed by debinding and sintering. The capillary structure prepared by this invention has uniform dimensions of each component unit, resulting in uniform stress transmission under load, thus avoiding stress concentration and giving the composite material better structural load-bearing capacity and impact resistance. Consequently, the divertor used in the capillary structure exhibits high mechanical properties and thermal shock resistance.

[0029] (3) The capillary channel structure composed of periodic units provided by the present invention utilizes capillary action to enable lithium flow to be spread evenly on the target plate in the Li-CPS (Li-capillary channel structure) liquid-solid composite structure, and the film flow thickness and flow rate are stable and controllable, which greatly improves the service life. In addition, the capillary channel structure composed of periodic units provided by the present invention enables lithium and plasma reaction to proceed stably on the surface in the Li-CPS (Li-capillary channel structure) liquid-solid composite structure, and the surface thermal shock, irradiation intensity and corrosion are reduced.

[0030] (4) The preparation method of the present invention adopts photopolymerization 3D printing, which has high molding accuracy and high resolution, providing technical support for the precise preparation of paraffin preforms with capillary channel voids. It also fully leverages the strong design advantage of 3D printing technology. The prepared paraffin preforms can precisely control the structural parameters of the voids, laying the foundation for the integrated preparation of micron-level capillary channel structures.

[0031] (5) The metal slurry used in the preparation of composite materials in this invention has better fluidity and stability. It can completely fill the metal phase in the prefabricated skeleton with capillary pores using only a small amount of pneumatic pressure. The process is simple and the molding effect is better. Attached Figure Description

[0032] Figure 1 This is a flowchart of the tungsten-based medium-entropy material with capillary channel structure and its pressureless preparation method provided by the present invention.

[0033] Figure 2 This is a schematic diagram of a capillary channel structure applied to a divertor provided by the present invention; wherein: 1-capillary channel unit, 2-connecting layer.

[0034] Figure 3 This is a schematic diagram of the periodic constituent units of the capillary channel structure provided by the present invention; wherein: 11-channel module, 12-support, 13-base.

[0035] Figure 4 This is a front view schematic diagram of the capillary channel structure provided by the present invention.

[0036] Figure 5 This is a top view schematic diagram of the capillary channel structure provided by the present invention.

[0037] Figure 6 This is a schematic diagram of a prefabricated skeleton with capillary pores provided by the present invention.

[0038] Figure 7 This is a sintering process diagram of the pressureless preparation method provided by the present invention.

[0039] Figure 8This is a physical image of the prefabricated skeleton with capillary pores provided by the present invention.

[0040] Figure 9 This is a physical image of a tungsten-based medium-entropy alloy material with a capillary channel structure for use in divertors, provided by the present invention.

[0041] Figure 10 This is a compressive stress-strain curve of a tungsten-based medium-entropy alloy prepared by a pressureless preparation method provided by the present invention.

[0042] Figure 11 This is a microstructure and elemental distribution diagram of a tungsten-based medium-entropy alloy prepared by a pressureless preparation method provided by the present invention.

[0043] Figure 12 This invention provides the principle of protecting divertors from plasma radiation using a capillary channel structure.

[0044] Figure 13 This invention provides the principle of protecting divertors from thermal shock through a capillary channel structure. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0046] This invention provides a pressureless preparation method for a capillary channel structure based on a tungsten-based medium-entropy material for use in divertors, comprising capillary channel units and connecting layers arranged from top to bottom; the tungsten-based medium-entropy alloy material possesses high strength, toughness, radiation resistance, and thermal shock resistance, meeting the requirements of fusion reactor divertors; the pressureless preparation method includes the preparation of a polymer framework, the preparation of a metal slurry, hot pressing, and debinding sintering.

[0047] like Figure 1 As shown, the capillary channel units and connecting layers of the capillary channel structure are integrally fabricated using a pressureless fabrication method. A schematic diagram of the capillary channel structure is shown below. Figure 2 As shown, it includes capillary channel unit 1 and connecting layer 2. The capillary channel unit that makes up the capillary channel structure is as follows: Figure 3 As shown, the structure comprises three parts: a channel module 11, a support 12, and a base 13. The channel module 11 measures 2mm x 2mm x 2mm; the support 12 is 2mm high, with inward and outward inclinations of 75-80° and 70-75° respectively; and the base 13 measures 3mm x 3mm x 2mm. The front and top views of the capillary channel structure are shown below. Figure 4 and Figure 5 As shown, the spacing between adjacent pore units is 60 μm.

[0048] The capillary channel structure has advantages such as periodicity and micron-level capillary channels. The size of each component unit is uniform, and the stress transmitted under force is also uniform, avoiding stress concentration. This gives the composite material better structural load-bearing capacity and impact resistance. The capillary channel structure utilizes capillary action to spread the lithium flow evenly on the target plate, and the film thickness and flow rate are stable and controllable. It also realizes tritium production, which greatly improves the service life. The lithium and plasma reaction proceeds stably on the surface, and the surface thermal shock, irradiation intensity and corrosion are reduced.

[0049] The pressureless preparation method of this invention mainly includes the following steps:

[0050] Step 1: Prepare a prefabricated skeleton with capillary pores.

[0051] Specifically, a capillary channel structure with micron-level pores was designed, and a prefabricated skeleton model with the voids of this capillary channel structure was constructed. Using 54# paraffin wax as the molding material, the above model was formed using photopolymerization 3D printing, thereby obtaining a prefabricated skeleton with the voids of the capillary channel structure, such as... Figure 6 As shown in the figure. The capillary structure with micron-sized pores consists of capillary units and connecting layers, as shown in the figure. Figure 3 The system consists of three parts: channel module 11, measuring 2mm x 2mm x 2mm with a spacing of 60 μm between adjacent modules; support 12, 2mm high with inward and outward tilt angles of 75-80° and 70-75° respectively; base 13, measuring 3mm x 3mm x 2mm; and metal connecting layer, 2mm high. The photopolymerization 3D printing parameters are as follows: exposure power density of 7 mw / cm³. 2 The exposure time was 10 seconds, and the slice thickness was 30 μm. A paraffin prefabricated skeleton of the above three-dimensional model was rapidly prototyping using photopolymerization 3D printing. The finished skeleton is shown below. Figure 8 As shown.

[0052] Step 2: Prepare the metal paste.

[0053] Tungsten-based medium-entropy alloy powder was prepared by mechanical alloying. The grinding jar was made of WC; the grinding balls were also made of WC, with a mass of 1.875 kg, and the ratio of large, medium, and small balls was 2:4:3. W, Cu, Cr, and V metal powders were added to the first grinding jar in an atomic ratio close to 1:1:1:1, and Cu and Cr powders were added to the second grinding jar in an atomic ratio close to 3:2. Mechanical alloying was initiated at 250-300 rpm for 12-15 hours. The two powders were then mixed in a powder mixer for 20-24 hours to obtain tungsten-based medium-entropy alloy powder.

[0054] Paraffin wax and stearic acid are uniformly mixed according to a certain component ratio and then heated to a molten state. Tungsten-based medium-entropy alloy powder is preheated and added to the molten wax slurry. After stirring and degassing, a slurry with good fluidity and stability is prepared. Paraffin wax is used as a binder, and stearic acid is used as a surfactant; the preferred mass ratio of the two is 24:1. The mixture is placed in a stainless steel crucible and heated and stirred uniformly at a temperature of 180℃~200℃. The organic components in the slurry preferably account for 10%~15% of the total mass. The tungsten-based medium-entropy alloy powder is preheated at 60℃~80℃, and its preferred mass percentage in the slurry is 85%~90%. Degassing is performed by vacuum degassing, with the mixture evacuated to a set vacuum level and held at pressure for 15min~30min in a vacuum drying oven. The viscosity of the prepared metal slurry is less than 1 Pa·s.

[0055] Step 3: Place the paraffin preform with capillary channel structure voids into a hot press mold and preheat it to 60-80°C. Pour the metal slurry into the mold and use a pneumatic punch to apply pressure so that the metal slurry fills the paraffin preform densely. After cooling, a solid tungsten-based medium-entropy alloy capillary channel structure blank is obtained.

[0056] The heating temperature of the metal slurry is 180℃~200℃, and the heating temperature of the paraffin precast skeleton and mold is 60℃~80℃; the working pressure of the pneumatic punch is 0.2MPa~0.4MPa, the holding time is 20s~40s, and the cooling temperature is 20℃~30℃.

[0057] Step 4: The solid tungsten-based medium-entropy alloy capillary structure blank is placed in a tube furnace for degreasing treatment to remove organic components and paraffin preforms from the blank. Then, the tungsten-based medium-entropy alloy capillary structure is obtained through sintering.

[0058] The degreasing process is formulated based on the thermogravimetric analysis results curve, such as... Figure 7 As shown, the temperature is raised from room temperature to 200-250℃ and held for 1-2 hours, then gradually increased to 255℃-265℃, 275℃-285℃, and 295-305℃, and held for 1-1.5 hours respectively to ensure complete removal of the polymer backbone. The atmosphere is Ar gas, and the flow rate is controlled at 100 ml / min to ensure normal discharge of the polymer. The second degreasing process involves raising the temperature to 550-600℃ and holding for 2-3 hours in an atmosphere of Ar and H2 gas to ensure normal discharge of the binder. The sintering process is as follows: the sintering atmosphere is Ar gas, the heating rate is 4℃ / min~5℃ / min, the sintering temperature is 1500℃~1600℃, and the holding time is 2-3 hours.

[0059] Figure 12This invention provides a capillary channel structure that protects divertors from plasma radiation. Specifically, it utilizes capillary action to spread the lithium flow evenly on the target plate, ensuring stable and controllable film thickness and flow rate; the lithium-plasma reaction [Li+n=T+He] proceeds stably on the surface, reducing surface irradiation intensity and achieving tritium production.

[0060] Figure 13 This invention provides a capillary channel structure that protects divertors from thermal shock. Specifically, it utilizes capillary action to spread the lithium flow evenly on the target plate, ensuring stable and controllable film thickness and flow rate; the low-temperature lithium flow and high-temperature plasma stably exchange heat on the surface, thereby reducing surface thermal shock.

[0061] The present invention will be further described in detail below with reference to several specific embodiments.

[0062] Example 1

[0063] A pressureless preparation method for capillary channel structures based on tungsten-based medium-entropy materials for use in divertors, the structure of which is as follows: Figure 2 As shown, the material consists of capillary channel units 1 and connecting layers 2 made of tungsten-based medium-entropy alloy.

[0064] The capillary channel units and connecting layers of the capillary channel structure of this invention are integrally fabricated using a pressureless fabrication method. The capillary channel units constituting the capillary channel structure are as follows: Figure 3 As shown, the capillary channel unit includes a channel module 11, a support 12, and a base 13. The channel module 11 of the capillary channel unit has dimensions of 2mm*2mm*2mm and a spacing of 60μm. The base 12 of the capillary channel unit has a height of 2mm and inward and outward inclinations of 80° and 75°, respectively. The connecting layer 2 has a height of 2mm. It has advantages such as periodicity and micron-level capillary channels.

[0065] The capillary channel unit and the connecting layer are integrally prepared by the tungsten-based medium-entropy alloy using the pressureless preparation method. The capillary channel unit achieves capillary channels by controlling the periodic arrangement of the spacing. The base is used to connect the capillary channel unit and the connecting layer, and the connecting layer is used to connect with the divertor section.

[0066] like Figure 1 As shown, a method for preparing capillary channel structures based on tungsten-based medium-entropy materials is described, and the preparation steps are as follows:

[0067] (1) Preparation of capillary channel structure polymer skeleton: Based on the capillary channel structure, a three-dimensional model with capillary channel structure gaps was constructed. A mixture of 54# paraffin and stearic acid was used as the molding material. The above three-dimensional model was formed by photopolymerization 3D printing, thereby obtaining a paraffin preform skeleton with capillary channel gaps.

[0068] (2) Preparation of metal slurry: Four metal powders, W, Cu, Cr and V, were added to the first ball mill jar in an atomic ratio of approximately 1:1:1:1, and Cu and Cr powders were added to the second ball mill jar in an atomic ratio of approximately 3:2. Mechanical alloying was started at a speed of 250 rpm and a ball milling time of 15 h. The two powders were then mixed in a powder mixer for 20 h to obtain tungsten-based medium-entropy alloy powder. The metal powder was preheated and added to a mixture of paraffin wax and stearic acid melted at 180 °C. After stirring and degassing, a slurry with good fluidity and stability was prepared. Paraffin wax and stearic acid were uniformly mixed according to a certain component ratio and then heated to a molten state. The tungsten-based medium-entropy alloy powder was preheated and added to the molten wax slurry. After stirring and degassing, a slurry with good fluidity and stability was prepared. Paraffin wax is used as a binder, stearic acid is used as a surfactant, and the preferred mass ratio of the three is 24:1. The mixture is placed in a stainless steel crucible and heated and stirred until homogeneous. The heating temperature is 180°C, and the organic components preferably constitute 10% of the total mass of the metal slurry. The tungsten-based medium-entropy alloy powder is preheated to 80°C, and its preferred mass percentage in the metal slurry is 90%. Degassing is performed using a vacuum degassing method, by evacuating to a set vacuum level in a vacuum drying oven and holding the pressure for 15 minutes. The viscosity of the prepared metal slurry is less than 1 Pa·s.

[0069] (3) Hot pressing: The precast skeleton described in step S1 is placed in the hot pressing mold and preheated to 60°C. The metal slurry described in step S2 is poured into the mold. The metal slurry is filled densely in the paraffin precast skeleton by applying pressure using a pneumatic punch. After cooling, a solid tungsten-based medium-entropy alloy channel structure blank is obtained. The heating temperature of the metal slurry is 180°C, and the heating temperature of the paraffin precast skeleton and the mold is 60°C. The working pressure of the pneumatic punch is 0.3MPa, the holding time is 25s, and the cooling temperature is 20°C.

[0070] (4) Degreasing and sintering: The blank described in step S3 is degreased to remove the paraffin in the blank, and then sintered to obtain a tungsten-based medium-entropy alloy pore structure material. The degreasing process is based on the thermogravimetric analysis results curve. The temperature is raised from room temperature to 200℃ and held for 1 hour. Then, the temperature is gradually increased to 275℃ and 300℃ and held for 1.5 hours respectively to ensure that the polymer skeleton is completely removed. The atmosphere is Ar gas and the flow rate is controlled at 100 ml / min to ensure that the polymer is discharged normally. The second degreasing process is to raise the temperature to 550℃ and hold for 2 hours. The atmosphere is Ar gas and H2 gas to ensure that the binder is discharged normally. The sintering process is as follows: the sintering atmosphere is Ar gas, the heating rate is 4℃ / min, the sintering temperature is 1600℃, and the holding time is 3 hours.

[0071] The resulting tungsten-based medium-entropy alloy capillary channel product is as follows: Figure 9 As shown, complex structures are thus formed.

[0072] Please see Figure 10 Adding the CuCr alloy phase to the WCrVCu alloy improves both the bending strength and bending toughness of the material.

[0073] Please see Figure 11 Adding a CuCr alloy phase to the WCrVCu alloy improves the material's density by filling the pores in the WCrVCu structure.

[0074] Example 2

[0075] A pressureless preparation method for capillary channel structures based on tungsten-based medium-entropy materials for use in divertors, comprising the following steps:

[0076] (1) First, a three-dimensional model with capillary channel voids was constructed using the modeling software MATLAB, such as... Figure 6 As shown in the figure. The capillary channel unit and the metal connecting layer of the capillary channel structure are integrally prepared by the pressureless preparation method described in the claims. A schematic diagram of the capillary channel structure is shown in the figure. Figure 2 As shown. The capillary channel units that make up the capillary channel structure are as follows: Figure 3 As shown, it consists of three parts: the channel module 11 has dimensions of 2mm*2mm*2mm; the support 12 has a height of 2mm and inward and outward inclinations of 80° and 70° respectively; the base 13 has dimensions of 3mm*3mm*2mm. The front view and top view of the capillary channel structure are shown below. Figure 4 and Figure 5 As shown, the spacing between adjacent channel units is 70 μm. A paraffin prefabricated skeleton of the above three-dimensional model was rapidly prototyping using photopolymerization 3D printing. The finished skeleton is shown below. Figure 8 As shown.

[0077] (2) Preparation of tungsten-based medium-entropy alloy powder by mechanical alloying. The grinding jar was made of WC; the grinding balls were also made of WC, with a mass of 1.875 kg, and the ratio of large, medium, and small balls was 2:4:3. W, Cu, Cr, and V metal powders were added to the first grinding jar in an atomic ratio of approximately 1:1:1:1, and Cu and Cr powders were added to the second grinding jar in an atomic ratio of approximately 3:2. Mechanical alloying was started at a speed of 280 rpm for 12 h. The two powders were then mixed in a powder mixer for 24 h to obtain tungsten-based medium-entropy alloy powder.

[0078] Paraffin wax and stearic acid are uniformly mixed according to a certain component ratio and then heated to a molten state. Tungsten-based medium-entropy alloy powder is preheated and added to the molten wax slurry. After stirring and degassing, a slurry with good fluidity and stability is prepared. Paraffin wax is used as a binder, and stearic acid is used as a surfactant; the preferred mass ratio of the three is 24:1. The mixture is placed in a stainless steel crucible and heated and stirred uniformly at 200°C. The organic components preferably account for 12% of the total mass of the metal slurry. The tungsten-based medium-entropy alloy powder is preheated at 70°C, and its preferred mass percentage in the metal slurry is 88%. Degassing is performed by vacuum degassing, with the vacuum level evacuated to a set degree and maintained at pressure for 20 minutes in a vacuum drying oven. The viscosity of the prepared metal slurry is less than 1 Pa·s.

[0079] (3) A paraffin wax preform with capillary channel structure is placed in a hot press mold and preheated together. The metal slurry is poured into the mold, and pressure is applied using a pneumatic punch to make the metal slurry fill the paraffin wax preform densely. After cooling, a solid tungsten-based medium-entropy alloy capillary channel structure blank is obtained. The heating temperature of the metal slurry is 200°C, and the heating temperature of the paraffin wax preform and the mold is 80°C. The working pressure of the pneumatic punch is 0.4 MPa, the holding time is 40 s, and the cooling temperature is 20°C.

[0080] (4) The solid tungsten-based medium-entropy alloy capillary structure blank is placed in a tube furnace for degreasing treatment to remove organic components and paraffin preforms from the blank, and then the tungsten-based medium-entropy alloy capillary structure is obtained through sintering process.

[0081] The degreasing process is formulated based on the thermogravimetric analysis results curve, such as... Figure 7 As shown, the temperature was raised from room temperature to 250℃ and held for 1 hour, then gradually increased to 260℃, 280℃, and 300℃, and held for 1 hour each time to ensure complete removal of the polymer backbone. The atmosphere was Ar gas, and the flow rate was controlled at 100 ml / min to ensure normal discharge of the polymer. The second degreasing process involved raising the temperature from 300℃ to 600℃ and holding for 2 hours. The atmosphere was a mixture of Ar and H2 gas to ensure normal discharge of the binder. The sintering process was as follows: the sintering atmosphere was Ar gas, the heating rate was 5℃ / min, the sintering temperature was 1550℃, and the holding time was 2 hours.

[0082] Example 3

[0083] A tungsten-based medium-entropy material with a capillary structure for use in divertors and its pressureless preparation method are disclosed. The preparation steps are as follows:

[0084] (1) First, a three-dimensional model with capillary channel voids was constructed using the modeling software MATLAB, such as... Figure 6As shown in the figure. The capillary channel unit and the metal connecting layer of the capillary channel structure are integrally prepared by the pressureless preparation method described in the claims. A schematic diagram of the capillary channel structure is shown in the figure. Figure 2 As shown. The capillary channel units that make up the capillary channel structure are as follows: Figure 3 As shown, it consists of three parts: the channel module 11 has dimensions of 2mm*2mm*2mm; the support 12 has a height of 2mm and inward and outward inclinations of 75° and 70° respectively; the base 13 has dimensions of 3mm*3mm*2mm. The front view and top view of the capillary channel structure are shown below. Figure 4 and Figure 5 As shown, the spacing between adjacent channel units is 60 μm. A paraffin prefabricated skeleton of the above three-dimensional model was rapidly prototyping using photopolymerization 3D printing. The finished skeleton is shown below. Figure 8 As shown.

[0085] (2) Preparation of tungsten-based medium-entropy alloy powder by mechanical alloying. The grinding jar was made of WC; the grinding balls were also made of WC, with a mass of 1.875 kg, and the ratio of large, medium and small balls was 2:4:3. Four metal powders, W, Cu, Cr and V, were added to the first grinding jar in an atomic ratio of approximately 1:1:1:1, and Cu and Cr powders were added to the second grinding jar in an atomic ratio of approximately 3:2. Mechanical alloying was started at a speed of 250 rpm and a grinding time of 12 h. The two powders were then mixed in a powder mixer for 24 h to obtain tungsten-based medium-entropy alloy powder.

[0086] Paraffin wax and stearic acid are uniformly mixed according to a certain component ratio and then heated to a molten state. Tungsten-based medium-entropy alloy powder is preheated and added to the molten wax slurry. After stirring and degassing, a slurry with good fluidity and stability is prepared. Paraffin wax is used as a binder, and stearic acid is used as a surfactant; the preferred mass ratio of the three is 24:1. The mixture is placed in a stainless steel crucible and heated and stirred uniformly at a temperature of 190°C. The organic components in the slurry preferably account for 15% of the total mass. The tungsten-based medium-entropy alloy powder is preheated at 70°C, and its preferred mass percentage in the slurry is 85%. Degassing is performed by vacuum degassing, with the vacuum level evacuated to a set degree and maintained at pressure for 15 minutes in a vacuum drying oven. The viscosity of the prepared metal slurry is less than 1 Pa·s.

[0087] (3) A paraffin wax preform with capillary channel structure is placed in a hot press mold and preheated together. The metal slurry is poured into the mold, and pressure is applied using a pneumatic punch to make the metal slurry fill the paraffin wax preform densely. After cooling, a solid tungsten-based medium-entropy alloy capillary channel structure blank is obtained. The heating temperature of the metal slurry is 180°C, and the heating temperature of the paraffin wax preform and the mold is 80°C. The working pressure of the pneumatic punch is 0.3 MPa, the holding time is 20 s, and the cooling temperature is 20°C.

[0088] (4) The solid tungsten-based medium-entropy alloy capillary structure blank is placed in a tube furnace for degreasing treatment to remove organic components and paraffin preforms from the blank, and then the tungsten-based medium-entropy alloy capillary structure is obtained through sintering process.

[0089] The degreasing process is formulated based on the thermogravimetric analysis results curve, such as... Figure 7 As shown, the temperature was raised from room temperature to 230℃ and held for 1 hour, then gradually increased to 260℃, 280℃, and 300℃, and held for 1 hour each time to ensure complete removal of the polymer backbone. The atmosphere was Ar gas, and the flow rate was controlled at 100 ml / min to ensure normal discharge of the polymer. The second degreasing process involved raising the temperature from 300℃ to 580℃ and holding for 2 hours. The atmosphere was a mixture of Ar and H2 gas to ensure normal discharge of the binder. The sintering process was as follows: the sintering atmosphere was Ar gas, the heating rate was 4℃ / min, the sintering temperature was 1550℃, and the holding time was 3 hours.

[0090] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A pressureless preparation method for capillary channel structures based on tungsten-based medium-entropy materials for use in divertors, characterized in that, Includes the following steps: (1) A three-dimensional model is constructed based on the capillary channel structure, which includes multiple capillary channel units arranged in a row and column periodically and a connecting layer, wherein the connecting layer is located at the bottom of the capillary channel unit; there are gaps between each capillary channel unit; any one of the capillary channel units includes a base, multiple supports located on the base and a channel module located on each support, and there are gaps between each channel module and each support; using the three-dimensional model, a mixture of paraffin wax and stearic acid is used as the molding material to prepare a paraffin wax prefabricated skeleton with capillary channel gaps; (2) Add four metal powders, W, Cu, Cr and V, to the first ball mill jar, and add two metal powders, Cu and Cr, to the second ball mill jar. Then, ball mill the substances in the first ball mill jar and the substances in the second ball mill jar. Then mix the powders in the first ball mill jar and the second ball mill jar to obtain tungsten-based medium entropy alloy powder. Paraffin wax and stearic acid are thoroughly mixed and then heated to a molten state to obtain a paraffin-based adhesive; the tungsten-based medium-entropy alloy powder is preheated and added to the paraffin-based adhesive to obtain a metal slurry; (3) After preheating the paraffin preform obtained in step (1), inject the metal slurry obtained in step (2) into it, and use a hot press casting die to make the metal slurry fully fill the paraffin preform. After cooling, a tungsten-based medium-entropy alloy channel structure blank is obtained. (4) The tungsten-based medium-entropy alloy pore structure blank obtained in step (3) is degreased and then sintered to obtain a capillary pore structure based on tungsten-based medium-entropy material.

2. The pressureless preparation method for capillary channel structures based on tungsten-based medium-entropy materials applied to divertors as described in claim 1, characterized in that, In step (4), the degreasing process includes two stages; First stage: Under an inert gas atmosphere, the temperature is raised to 200-250℃ and held for 1-2 hours, then raised to 255-265℃, 275-285℃ and 295-305℃ and held for 1 hour each to remove the paraffin-based adhesive. Second stage: Continue heating to 550-600℃ and hold for 2-3 hours in a mixed atmosphere of inert gas and hydrogen to remove the paraffin preform and reduce the oxidized metal.

3. The pressureless preparation method of capillary channel structures based on tungsten-based medium-entropy materials for use in divertors as described in claim 1, characterized in that... In step (4), the sintering specifically involves heating to 1500-1600℃ at a heating rate of 4-5℃ / min and holding at that temperature for 2-3 hours.

4. The pressureless preparation method of capillary channel structures based on tungsten-based medium-entropy materials for use in divertors as described in claim 1, characterized in that, In step (2), the ball milling speed is 250-300 rpm and the ball milling time is 12-15 h.

5. The pressureless preparation method of capillary channel structure based on tungsten-based medium-entropy material for use in divertors as described in claim 1, characterized in that, In step (2), the preheating temperature of the medium entropy alloy powder is 60-80℃.

6. The pressureless preparation method of capillary channel structure based on tungsten-based medium-entropy material for use in divertors as described in claim 1, characterized in that, In step (1), the paraffin preform with capillary pores is prepared by photopolymerization 3D printing technology.

7. The pressureless preparation method of capillary channel structure based on tungsten-based medium-entropy material for use in divertors as described in claim 1, characterized in that, In step (2), the mass percentage of paraffin-based adhesive in the metal slurry is 10-15%.

8. The pressureless preparation method of capillary channel structure based on tungsten-based medium-entropy material for use in divertors as described in claim 1, characterized in that, The gaps between each capillary channel unit and between each channel module have the same width, which is 60-100 μm.

9. The pressureless preparation method of capillary channel structures based on tungsten-based medium-entropy materials for use in divertors as described in claim 1, characterized in that, The height of the connecting layer is 2-2.5 mm.

10. The pressureless preparation method of capillary channel structures based on tungsten-based medium-entropy materials for use in divertors as described in claim 1, characterized in that, The height of the base is 2-2.5 mm.

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