Tungsten infiltrated copper composite material and preparation method thereof

Abstract

The invention belongs to the technical field of composite material preparation, and particularly relates to a tungsten infiltrated copper composite material and a preparation method thereof. According to the invention, through a multi-scale through pore network formed by'prefabricated material construction ', molten copper liquid can be rapidly filled along a large pore channel and fully permeates into the tail end of a small pore, so that the defect of'black core' generated by closed pores is thoroughly avoided. According to the prepared composite material, the tungsten phase and the copper phase respectively form a stable and communicated three-dimensional network, so that the unification of high conductivity (greater than or equal to 60% IACS), high strength and toughness (hardness greater than or equal to 100 HB) and excellent arc ablation resistance is fundamentally and synergistically realized, and the long-standing limitation of'impossible performance triangle 'is effectively broken through. And the process is high in integration level, green and remarkable in strengthening effect, and process simplification, environmental protection strengthening and performance improvement are achieved at one stroke. The advantages of raw materials and process cost are outstanding, the industrialization prospect is wide, and the relationship among high performance, designability and mass productivity is perfectly balanced.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation technology, specifically relating to a tungsten-copper infiltrated composite material and its preparation method. Background Technology

[0002] Tungsten-copper composite (W-Cu) is a pseudo-alloy combining tungsten (W) with its high melting point, high hardness, and low coefficient of thermal expansion with copper (Cu) which has high electrical and thermal conductivity and good ductility. This unique combination of properties makes it an irreplaceable key material under extreme operating conditions, widely used in electrical engineering, electronics, and high-end equipment. In these high-end applications, especially in ultra-high voltage electrical contacts and electromagnetic rails, tungsten-copper materials need to operate stably under extreme environments of "high current, strong arc, high friction, and high load." This requires the material to simultaneously meet three core performance indicators: high strength / high toughness, high electrical / thermal conductivity, and excellent resistance to arc erosion.

[0003] However, due to the significant differences in physical properties and immiscibility between tungsten and copper, these three performance indicators exhibit a strong mutual constraint relationship in existing technologies, constituting the "performance impossibility triangle" of WCu composite materials: To increase strength, it is necessary to increase the content and continuity of the hard tungsten phase, but this will break the conductive network of copper and reduce its electrical and thermal conductivity.

[0004] Improving conductivity requires increasing the copper phase content and ensuring the three-dimensional connectivity of the copper phase, but this weakens the strengthening effect of tungsten and reduces its strength.

[0005] Improving resistance to arc erosion requires special microstructures to stabilize the arc and reduce erosion, but this often conflicts with the former two.

[0006] Therefore, how to synergistically improve the strength, conductivity and ablation resistance of tungsten-copper materials through innovative material design and preparation processes, and break the "performance trilemma", is a core technical challenge currently faced by those skilled in the art.

[0007] To address the aforementioned contradictions, researchers explored two core approaches: first, optimizing the microscopic and macroscopic structural distribution of the tungsten / copper two-phase system; and second, adding ablation-resistant stabilizers to the material.

[0008] (1) Technical solutions for optimizing the tungsten-copper two-phase structure. The core objective is to construct an ideal "double continuous interpenetrating network structure" in tungsten-copper composite materials—that is, a high-strength tungsten skeleton and a conductive copper network interwoven and continuously. The key lies in pre-preparing a tungsten skeleton with three-dimensional interconnected pores of controllable size. The main methods include: Melt infiltration (traditional mainstream process): First, tungsten powder is pressed into a blank and sintered to form a "tungsten skeleton" with internal pores; then, at a high temperature (exceeding the melting point of copper, 1083℃), molten copper is infiltrated into the pores of the tungsten skeleton by capillary force, and after cooling, a dense WCu composite material is obtained. Conventional melt infiltration relies on the pores provided by the random distribution of tungsten particles, resulting in insufficient electrical conductivity in the WCu composite material.

[0009] Powder metallurgy sintering: Tungsten powder and copper powder are directly mixed evenly, pressed into shape, and then sintered at a high temperature (usually slightly below the melting point of copper) for a long time, so that the powder particles are bonded together through atomic diffusion to form WCu composite materials. Although the sintering method can prepare composite materials with high copper content, solid-state sintering results in low density and limited improvement in conductivity, while greatly sacrificing strength and toughness.

[0010] Advanced framework fabrication methods (developed to improve upon traditional methods): These methods do not rely on the pores formed by the random stacking of tungsten powder, but rather actively "create pores". Examples include template / slurry methods, additive manufacturing (3D printing) methods, and fiber / wire mesh framework methods.

[0011] (2) Technical solution of adding anti-ablation third phase (stabilizer). Add a small amount of high melting point and high stability particles, such as nano lanthanum oxide (La2O3), yttrium oxide (Y2O3), aluminum oxide (Al2O3) or graphene, to the tungsten or copper matrix to stabilize the arc and prevent it from excessively ablating the copper.

[0012] Tungsten-copper composite materials face severe challenges under extreme conditions such as high current, strong friction, and arc erosion in ultra-high voltage electrical contacts and electromagnetic rails, requiring materials to simultaneously possess excellent high conductivity, high strength and toughness, and outstanding ablation resistance. However, conventional preparation methods suffer from problems such as uncontrollable porosity, unadjustable composition and structure, poor structural uniformity, uneven dispersion, complex processes, and difficulty in mass production. These methods fail to resolve the "performance impossibility triangle" contradiction of microstructure (as with traditional methods), or introduce new problems that are difficult to industrialize, costly, or environmentally problematic (such as advanced manufacturing methods and wet chemical methods) while solving structural issues. Currently, there is still a lack of a preparation method for tungsten-copper composite materials that can simultaneously achieve high performance, high uniformity, simple processing, and suitability for large-scale production. Summary of the Invention

[0013] The technical problem to be solved by the present invention is to provide a tungsten copper infiltrated composite material and its preparation method. The internal pore structure of the material is composed of micro-pores and macro-pores. Through the multi-scale interconnected pore network formed by "pre-fabrication", the molten copper liquid can be rapidly filled along the large pore channels and fully penetrate into the ends of small pores. This completely avoids the "black core" defect caused by closed pores in the traditional melt infiltration method. It fundamentally achieves the unity of high conductivity (≥70% IACS), high strength and toughness (hardness ≥120 HB) and excellent arc erosion resistance.

[0014] The technical solution adopted is as follows: A method for preparing a tungsten-copper infiltrated composite material specifically includes the following steps: (1) Preparation of the mixture: The raw materials include tungsten powder, binder, and / or stabilizer; wherein, the stabilizer is optional and may or may not be added; Mix the raw materials to form a uniform slurry or paste; (2) Preparation and forming of “preform”: The preform is a unit body with different geometric shapes. The slurry or paste from step (1) is processed into a unit body with a geometric shape. The preset geometric shape includes spherical, rod-shaped or tubular. (3) Assemble the blank: Use at least one preform with a preset geometric shape as a basic unit, fill it into the mold in a preset manner, and assemble it to form a blank with a macroscopic design; (4) Degreasing, sintering and melting: The mold containing the blank is placed in the degreasing and sintering furnace. Under the protective atmosphere, the temperature is raised to 100-1000℃ and kept at that temperature. The binder is decomposed and vaporized by the heat and carried away by the carrier gas, leaving tungsten powder particles and / or stabilizers, and degreasing is carried out. Continue heating to 1000-2400℃ under a protective atmosphere and hold at that temperature. The tungsten powder particles form a strong metallurgical bond through atomic diffusion. The green body shrinks and strengthens, eventually forming a tungsten skeleton. The sintered tungsten skeleton is brought into contact with a sufficient amount of copper block or copper sheet and placed together in a melting furnace. Under a protective atmosphere, the molten copper liquid is heated and rapidly and uniformly fills all the pores along the pre-designed through-pore network in the tungsten skeleton under the action of capillary force. After cooling, a dense tungsten-copper composite ingot with interwoven tungsten and copper phases is obtained.

[0015] Preferably, the average particle size of the tungsten powder is 0.1–20 micrometers; the binder is one of the following two types: Category A: Thermoplastic adhesive systems, including at least two of paraffin wax, high-density polyethylene, polypropylene, stearic acid, and polystyrene; Category B: Solution / slurry binder systems, including at least one of paraffin wax, phenolic resin, polyvinyl alcohol, and ethanol; The stabilizer comprises a main material and an auxiliary material. The main material and the auxiliary material of the stabilizer are mixed to obtain a dispersion system. The dispersion system is spray-dried to obtain a free-flowing fine powder. The main materials account for 10-50% of the total mass, while the auxiliary materials account for 50-90%. The main material is selected from at least one of the following: functional metal powder, functional metal compound powder, metal salt powder, and low-dimensional carbon material; The auxiliary material is selected from at least one of the following: polyvinylpyrrolidone, polymethyl methacrylate, dimethylformamide, polyvinyl alcohol, ethanol, and water; The binder comprises 30-70% by mass. The stabilizer comprises 0.001-1% by mass, with the remainder being tungsten powder.

[0016] Preferably, the functional metal powder, metal compound powder, or metal salt powder is selected from at least one of La, Ce, Sc, Y, W, Mo, Ti, Zr, V, Fe, Ni, Cu, and Al, or its oxides, nitrides, carbides, nitrates, carbonates, and sulfates; the low-dimensional carbon material is graphene or carbon nanotubes.

[0017] Preferably, when using a type A thermoplastic binder system, the tungsten powder, the type A binder, and the stabilizer are hot-mixed in an internal mixer at a temperature of 100–300°C to obtain a well-plasticized slurry; When using a type B solution / slurry binder system, the tungsten powder, the type B binder, and the stabilizer are mixed at room temperature or a suitable temperature using a planetary mixer or agitator to form a uniform slurry or paste.

[0018] Preferably, the method for preparing the spherical preform includes: processing the mixture into near-spherical units with a particle size of 50 to 1000 micrometers using granulation technology; The granulation technology involves extrusion, cutting, and then rounding. Specific steps include: S1: The well-plasticized feed material is continuously extruded through the extruder die; S2: Use a cutter to cut the extruded strip into small, approximately cubic pieces; S3: The small material block is dropped into a high-speed rotating spherical roller, where it tumbles and collides under the action of centrifugal force and friction, rounding off its edges and forming a spherical preform.

[0019] Preferably, the method for preparing the rod-shaped preform includes: extruding the feed material through a die into fine filaments with a diameter of 50 to 1000 micrometers, cutting the fine filaments into suitable lengths as needed, and controlling the ratio of traction speed to extrusion speed to form straight or spiral-shaped rod-shaped preforms.

[0020] Preferably, the tubular preform is a coated structure, and its preparation method includes: using coaxial coating extrusion technology to uniformly coat the feed material onto the surface of the core material to form a composite filament with a "skin-core" structure, and cutting the composite filament into a suitable length; The coaxial coating extrusion technology specifically includes: S1: Pass the core material through the axial through hole in the center of the extruder screw and guide it to the die head; S2: The heated and plasticized feed material is driven by the screw to meet the core material at the die head and evenly wrap around the core material to form a composite filament; S3: The composite filament is pulled forward at a controllable speed by a traction device, and the thickness of the coating layer is controlled to be 50-1000 micrometers by adjusting the matching of the traction speed and the extrusion speed, forming a tubular preform with a straight or non-linear shape. The core material is a metal wire of a suitable diameter or a biodegradable polymer wire, which can be decomposed in the subsequent degreasing / sintering process.

[0021] Preferably, the preform is a preform with a bimodal or multimodal pore distribution, a functionally graded material preform, a tubular channel preform, or a preform containing internal spiral channels; wherein, two or more spherical preforms with different particle sizes are mixed and filled into a mold to form a preform with a bimodal or multimodal pore distribution; spherical preforms and rod-shaped preforms are combined and filled into a mold, wherein the rod-shaped preforms play a reinforcing and directional guiding role in the preform; powdered materials and tubular preforms are combined and filled into a mold, wherein the core material inside the tubular preforms forms a special channel in the preform for subsequent processes; different types, sizes, or materials of preforms are filled into different areas of the mold to prepare a functionally graded material preform with a gradient in composition or porosity; tubular preforms are filled into a mold, and spherical or near-spherical preforms are filled into its cavity to form a preform with different internal and external pore structures; and spiral tubular preforms are used for assembly to form spiral channels inside the preform.

[0022] Preferably, in step (4), the protective atmosphere is vacuum, nitrogen, argon, hydrogen or argon-hydrogen mixture; the degreasing is kept at a temperature of 2 to 20 hours, and the sintering is kept at a temperature of 0.1 to 3 hours; during the melting and infiltration process, the temperature is heated to 1100 to 1400°C (which needs to exceed the melting point of copper, 1083°C) and kept at a temperature of 1 to 10 hours.

[0023] The present invention also provides a method for preparing tungsten copper-infiltrated composite material, which has high electrical conductivity (≥70% IACS), high strength and toughness (hardness ≥120 HB) and excellent resistance to arc erosion.

[0024] The final ingot (tungsten-copper composite material) after melting and infiltration is then subjected to necessary machining (such as turning, milling, and grinding) to obtain the required parts.

[0025] Compared with the prior art, the significant advantages of the present invention are as follows: (1) Synergistic breakthrough in performance bottlenecks, resulting in excellent overall performance. This invention utilizes a multi-scale interconnected pore network formed by "pre-fabricated material construction," enabling molten copper to rapidly fill along large pore channels and fully penetrate into the ends of small pores, completely avoiding the "black core" defect caused by closed pores in traditional melt infiltration methods. The resulting composite material has a stable and interconnected three-dimensional network formed by the tungsten and copper phases, thereby fundamentally achieving a synergistic unity of high conductivity (≥70% IACS), high strength and toughness (hardness ≥120HB), and excellent resistance to arc erosion, effectively breaking through the long-standing "performance impossible triangle" limitation.

[0026] (2) Flexible and controllable structural design enables "adjustable" material properties. This invention pioneers a paradigm of "construction" using "prefabricated materials" as the basic structural unit. By changing the shape (sphere, rod, tube), size, and combination method of the prefabricated materials, the size, distribution, gradient, and even orientation of macroscopic pores in the blank can be flexibly and precisely designed, much like building blocks. This means that key properties such as the thermal / electrical conduction path, mechanical bearing direction, and copper content distribution of the material can all be pre-programmed, thereby enabling the convenient fabrication of parts with gradient functions or anisotropy to meet the specific needs of various differentiated application scenarios such as high-voltage electrical contacts and directional heat sinks.

[0027] (3) High process integration, environmental friendliness, and significant strengthening effect. This invention incorporates the stabilizer using a dry method during the feed preparation stage, resulting in seamless process integration, no pollution, and initial uniform dispersion of the stabilizer in the matrix. In subsequent sintering, these stabilizer particles effectively pin grain boundaries, strengthen the tungsten skeleton, and play a key role in stabilizing the arc and reducing ablation in the final composite material, achieving process simplification, environmental enhancement, and performance improvement in one fell swoop. In contrast, existing technologies suffer from cumbersome steps, easy particle agglomeration, and wastewater pollution.

[0028] (4) The invention boasts significant advantages in raw material and process costs, and has broad prospects for industrialization. It requires no special raw materials; conventional and inexpensive reduced tungsten powder is sufficient, eliminating the need for expensive spherical or nano-powders. The core "pre-formed material" preparation (extrusion and granulation) and "construction" steps employ mature, efficient, and easily scalable unit operations, resulting in a simple, stable, and highly repeatable process. Therefore, this invention achieves a leap in performance and design freedom with minimal cost increase, perfectly balancing the relationship between "high performance," "designability," and "mass production capability," thus possessing extremely high industrial application value and market competitiveness. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the spherical preform preparation device of the present invention; A1 is the extruded material, A2 is the cutter, A3 is the sheared material, A4 is the rounding device, and A5 is the spherical preform.

[0030] Figure 2 This is a schematic diagram of the tubular (coated) preform preparation device of the present invention; B1 is the extruder barrel, B2 is the screw with a central hole, B3 is the motor, B4 is the wire feeder, B5 is the copper wire, B6 is the mixture, B7 is the die head, B8 is the traction device, B9 is the cutter, and B10 is the coating material (tubular preform).

[0031] Figure 3 This is a schematic diagram of a multi-scale precast material assembly; C1 is a mold, C2 is a small spherical precast material, C3 is a large spherical precast material, C4 is a rod-shaped precast material, C5 is a powdery precast material, C6 is a tubular precast material, C7 is a spiral precast material, C8 is a curved precast material, and C9 is a twisted precast material.

[0032] Figure 4 These are photographs of the preforms prepared according to the present invention; D1 is spherical, D2 is filamentous, D3 is tubular, and D4 is spiral.

[0033] Figure 5 These are metallographic images of WCu prepared according to the present invention, wherein E1 corresponds to the micrograph of the material prepared in Example 1, and E2 corresponds to the micrograph of the material prepared in Example 2, wherein the dark color represents the tungsten phase and the light color represents the copper phase.

[0034] Figure 6 The sample prepared in Example 3 is a copper infiltrated sample with a multi-scale porous tungsten skeleton surface morphology after an ablation experiment. Detailed Implementation

[0035] The accompanying drawings are for illustrative purposes only. To make the objectives, technical solutions, and beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. Some embodiments of the present invention will be described more fully below with reference to the accompanying drawings, and some, but not all, embodiments will be shown. In fact, various embodiments of the present invention can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein.

[0036] Example 1 A method for preparing tungsten-copper infiltrated composite material, using W-shaped preforms. 40 Cu 60 (i.e., the volume ratio of tungsten to copper is 40:60) Sample, microstructure as follows Figure 5 As shown in E1. The preparation process of this sample is as follows: The raw material is reduced tungsten powder with an average particle size of 5μm; the binder composition is: paraffin wax (PW) 65%, high-density polyethylene (HDPE) 10%, polypropylene (PP) 15%, and stearic acid (SA) 5%.

[0037] Tungsten powder and 50% binder were mixed evenly and then processed into feedstock using an internal mixer at a temperature of 160°C. The feedstock was then mechanically crushed to obtain spherical preforms with an average particle size of 105 μm.

[0038] The preform was loosely packed into a crucible and degreased at 1000°C for 1 hour and sintered at 1200°C for 2 hours under an argon atmosphere to obtain a tungsten skeleton. The tungsten skeleton and a copper block were placed in a graphite crucible and melt-infiltrated at 1300°C for 1 hour under an argon atmosphere to obtain a WCu composite material.

[0039] The sample was tested for performance: its hardness was 123 HB, its electrical conductivity was 77% IACS, and after being ablated by electric arc for 2 seconds, there were no obvious defects such as pitting or pilling on the surface.

[0040] (2) Example 2 A method for preparing tungsten-copper infiltrated composite material, using tubular preforms to prepare W 30 Cu 70 Sample, microstructure such as Figure 5 As shown in E2. The preparation process of this sample is as follows: The tungsten powder and binder are the same as in the previous example. This example adds a stabilizer, with a mass percentage of 0.3%. The stabilizer is prepared by mixing 25% lanthanum nitrate, 20% copper nitrate, 50% ethanol, and 5% polyvinyl alcohol into a slurry, and then using a centrifugal spray dryer to prepare stabilizer particles.

[0041] Mix 50% tungsten powder, 49% binder, and 1% stabilizer evenly, and then knead the mixture into feedstock using the same method as above. Feed the feedstock into... Figure 2 The extrusion device shown places a copper wire with a diameter of 0.2 mm into the die head hole, and feeds the material and extrudes it synchronously with the copper wire to form a coated preform.

[0042] The preform was cut into 10mm long rods, arranged in a crucible, and then degreased, sintered, and melt-infiltrated under an argon atmosphere. Other specific methods were the same as in Example 1.

[0043] The sample had a hardness of 102 HB and an electrical conductivity of 82% IACS. After being ablated by electric arc for 2 seconds, there were no obvious defects such as pitting or balling on the surface.

[0044] Example 3 A method for preparing tungsten-copper infiltrated composite material is disclosed. In this example, a stabilizer is added, with a mass percentage of 0.5%. The W-type composite material is prepared using extrusion 3D printing. 50 Cu 50 The surface morphology of the sample after arc ablation is as follows: Figure 6 As shown.

[0045] The preparation process of this sample is as follows: The feed preparation method is the same as in Example 1. The feed is fed into an extrusion 3D printer to print a sample with large square pores, and then debinding, sintering, and melting are performed in the same way as in Example 1. After arc ablation for 2 seconds, there are no obvious pits, balling, or other defects on the surface.

[0046] Other areas not mentioned are the same as in Example 1.

[0047] Example 4 A method for preparing tungsten-copper infiltrated composite material is disclosed. In this example, a stabilizer is added, with a mass percentage of 0.8%. The W-shaped preform is prepared by filling a mold with a combination of spherical and rod-shaped preforms. 40 Cu 60 Sample.

[0048] Other areas not mentioned are the same as in Example 1.

[0049] Example 5 A method for preparing a tungsten-copper infiltrated composite material uses a combination of preforms of different types, sizes, or materials. Specifically, the upper part is a spherical W preform, the lower part is a spherical Cr preform, and after copper infiltration, the upper part is W. 40 Cu 60 The lower part is Cr 30 Cu 70 This allows for the preparation of functionally graded material preforms with varying compositions or porosities, and the fabrication of W... 40 Cu 60 Sample. Other details not mentioned are the same as in Example 1.

[0050] Example 6 A method for preparing tungsten-copper infiltrated composite material involves assembling a non-spiral tubular preform to create a spiral channel within the preform, resulting in a W-shaped composite material. 40 Cu 60 The sample, and other parts not mentioned are the same as in Example 1.

[0051] The performance of the tungsten-copper infiltrated composite materials prepared in Examples 1-6 was tested, and the data obtained are shown in Table 1.

[0052] Table 1. Performance comparison of tungsten-copper infiltrated composite materials prepared in Examples 1-6 The technical solution of this invention is suitable for the preparation and application of tungsten-copper composite materials with high copper content.

[0053] Besides directly mixing the stabilizer powder into the feed, it can also be introduced after sintering to obtain a porous tungsten framework using a solution impregnation method. A liquid containing a stabilizer precursor (such as a nitrate solution) or a nanoparticle dispersion is impregnated onto the inner surface of the pores of the tungsten framework. After drying and thermal decomposition, the stabilizer oxide adheres to the pore surface, achieving the same effect of improving ablation resistance and framework strength.

[0054] When preparing tubular (coated) preforms, the copper wire core can be replaced with other materials that can be thermally decomposed or chemically removed in subsequent processes, such as thermoplastic polymer filaments like polyamide (PA), polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), polyethylene (PE), and polypropylene (PP). Furthermore, when preparing hollow spherical preforms, polyurethane (PU) foam balls or polystyrene (PS) microspheres can be used as sacrificial templates. Tungsten powder slurry is coated onto their surfaces, and after drying, the template is removed or sintered to decompose, thus obtaining the hollow spherical preform.

[0055] Preform forming technology can be used for spherical materials, in addition to "extrusion-cutting-spheroidization", conventional powder granulation technologies such as spray drying, centrifugal granulation, and fluidized bed granulation can also be used. For heated spheroidization, hot air can be introduced into a special spheroidization machine or a heating jacket can be used to promote the plasticization and spheroidization of the material blocks.

[0056] Tubular / coating materials: In addition to coaxial extrusion coating, coating (similar to spray painting) and slurry dip coating (repeatedly immersing the core material in a high solid content tungsten powder slurry and then drying) can also be used to form a coating layer on the surface of the core material.

[0057] Slurry-filling method: A unique alternative is to first weave copper wire into a network, or stack copper spheres or polymer spheres into a preform, and then extrude or inject a slurry made of tungsten powder and binder into the gaps of the preform. After solidification, the preform is debonded and sintered together. During sintering, the copper network or spheres melt, flow, or decompose, leaving behind the pores they originally occupied, ultimately forming a complex pore structure composed of a tungsten framework that replicates the structure of the initial preform.

[0058] Preform structure: Preforms are not limited to solid spheres, rods, or tubes. They can also be hollow spheres, porous spheres, hollow tubes, or irregularly shaped cross-section rods (such as gear-shaped or cross-shaped). These special shapes of preforms can bring more unique pore structures and properties to the final composite material.

[0059] The method of this invention is by no means limited to the tungsten-copper system. Its core principle—constructing a porous framework through a designable preform and then performing melt infiltration—can be widely applied to the preparation of pseudo-alloys or composite materials containing other high / low melting point components. For example: High melting point components: molybdenum (Mo), titanium (Ti), tantalum (Ta), niobium (Nb), nickel-based superalloys, stainless steel, etc.

[0060] Low melting point components: aluminum (Al), magnesium (Mg), silver (Ag), zinc (Zn) and their alloys, etc.

[0061] This method is also applicable to the preparation of porous metallic materials with integrated structure and function.

[0062] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for preparing a tungsten-copper infiltrated composite material, characterized in that, Specifically, the steps include the following: (1) Preparation of the mixture: The raw materials include tungsten powder, binder, and / or stabilizer; Mix the raw materials to form a uniform slurry or paste; (2) Preparation and forming of "preform": The preform is a unit with different geometric shapes. The slurry or paste from step (1) is processed into a unit with a geometric shape. The preset geometric shape includes spherical, rod-shaped or tubular. (3) Assemble the blank: Use at least one preform with a preset geometric shape as a basic unit, fill it into the mold in a preset manner, and assemble it to form a blank with a macroscopic design; (4) Degreasing, sintering and melting: The mold containing the blank is placed in the degreasing and sintering furnace. Under the protective atmosphere, the temperature is raised to 100-1000℃ and kept at that temperature. The binder is decomposed and vaporized by the heat and carried away by the carrier gas, leaving tungsten powder particles and / or stabilizers, and degreasing is carried out. Continue heating to 1000-2400℃ under a protective atmosphere and hold at that temperature. The tungsten powder particles form a strong metallurgical bond through atomic diffusion. The green body shrinks and strengthens, eventually forming a tungsten skeleton. The sintered tungsten skeleton is brought into contact with a sufficient amount of copper block or copper sheet and placed together in a melting furnace. Under a protective atmosphere, the molten copper liquid is heated and rapidly and uniformly fills all the pores along the pre-designed through-pore network in the tungsten skeleton under the action of capillary force. After cooling, a dense tungsten-copper composite ingot with interwoven tungsten and copper phases is obtained.

2. The method for preparing a tungsten-copper infiltrated composite material according to claim 1, characterized in that, The average particle size of the tungsten powder is 0.1–20 micrometers; the binder is one of the following two types: Category A: Thermoplastic adhesive systems, including at least two of paraffin wax, high-density polyethylene, polypropylene, stearic acid, and polystyrene; Category B: Solution / slurry binder systems, including at least one of paraffin wax, phenolic resin, polyvinyl alcohol, and ethanol; The stabilizer comprises a main material and an auxiliary material. The main material and the auxiliary material of the stabilizer are mixed to obtain a dispersion system. The dispersion system is spray-dried to obtain a free-flowing fine powder. The main material accounts for 10-50% of the mass fraction of the stabilizer, and the auxiliary material accounts for 50-90% of the mass fraction of the stabilizer. The main material is selected from at least one of the following: functional metal powder, functional metal compound powder, metal salt powder, and low-dimensional carbon material; The auxiliary material is selected from at least one of the following: polyvinylpyrrolidone, polymethyl methacrylate, dimethylformamide, polyvinyl alcohol, ethanol, and water; The binder comprises 30-70% by mass, the stabilizer comprises 0-1% by mass, and the remainder is tungsten powder.

3. The method for preparing a tungsten-copper infiltrated composite material according to claim 2, characterized in that, The functional metal powder, metal compound powder, and metal salt powder are selected from at least one of La, Ce, Sc, Y, W, Mo, Ti, Zr, V, Fe, Ni, Cu, and Al, or their oxides, nitrides, carbides, nitrates, carbonates, and sulfates; the low-dimensional carbon material is graphene or carbon nanotubes.

4. The method for preparing a tungsten-copper infiltrated composite material according to claim 3, characterized in that, When using a type A thermoplastic binder system, the tungsten powder, the type A binder, and the stabilizer are hot-mixed in an internal mixer at a temperature of 100–300°C to obtain a well-plasticized slurry. When using a type B solution / slurry binder system, the tungsten powder, the type B binder, and the stabilizer are mixed at room temperature or a suitable temperature using a planetary mixer or agitator to form a uniform slurry or paste.

5. The method for preparing a tungsten-copper infiltrated composite material according to claim 1, characterized in that, The method for preparing the spherical preform includes: processing the mixture into near-spherical units with a particle size of 50 to 1000 micrometers using granulation technology; The granulation technology involves extrusion, cutting, and then rounding. Specific steps include: S1: The well-plasticized feed material is continuously extruded through the extruder die; S2: Use a cutter to cut the extruded strip into small, approximately cubic pieces; S3: The small material block is dropped into a high-speed rotating spherical roller, where it tumbles and collides under the action of centrifugal force and friction, rounding off its edges and forming a spherical preform.

6. The method for preparing a tungsten-copper infiltrated composite material according to claim 1, characterized in that, The method for preparing the rod-shaped preform includes: extruding the feed through a die into fine filaments with a diameter of 50 to 1000 micrometers, cutting the fine filaments into suitable lengths as needed, and controlling the ratio of traction speed to extrusion speed to form straight or spiral-shaped rod-shaped preforms.

7. The method for preparing a tungsten-copper infiltrated composite material according to claim 1, characterized in that, The tubular preform is a coated structure, and its preparation method includes: using coaxial coating extrusion technology to uniformly coat the feed material onto the surface of the core material to form a composite filament with a "skin-core" structure, and cutting the composite filament into a suitable length; The coaxial coating extrusion technology specifically includes: S1: Pass the core material through the axial through hole in the center of the extruder screw and guide it to the die head; S2: The heated and plasticized feed material is driven by the screw to meet the core material at the die head and evenly wrap around the core material to form a composite filament; S3: The composite filament is pulled forward at a controllable speed by a traction device, and the thickness of the coating layer is controlled to be 50-1000 micrometers by adjusting the matching of the traction speed and the extrusion speed, forming a tubular preform with a straight or non-linear shape. The core material is either a metal wire of a suitable diameter or a biodegradable polymer wire.

8. The method for preparing a tungsten-copper infiltrated composite material according to claim 1, characterized in that, The blank is a blank with a bimodal or multimodal pore distribution, a functionally graded material blank, a tubular channel blank, or a blank containing a spiral channel inside.

9. The method for preparing a tungsten-copper infiltrated composite material according to claim 1, characterized in that, In step (4), the protective atmosphere is vacuum, nitrogen, argon, hydrogen or argon-hydrogen mixture; the degreasing is kept at a temperature of 2 to 20 hours, and the sintering is kept at a temperature of 0.1 to 3 hours; the melting and infiltration process is heated to 1100 to 1400°C and kept at a temperature of 1 to 10 hours.

10. The tungsten-copper infiltrated composite material prepared by the method for preparing a tungsten-copper infiltrated composite material according to any one of claims 1-9.

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