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CN-121976104-A - Tungsten copper-infiltrated composite material and preparation method thereof

CN121976104ACN 121976104 ACN121976104 ACN 121976104ACN-121976104-A

Abstract

The invention belongs to the technical field of composite material preparation, and particularly relates to a tungsten copper-infiltrated composite material and a preparation method thereof. The invention forms a multi-scale through pore network through prefabricated construction, so that molten copper can be filled rapidly along a large pore channel and fully infiltrate into the tail end of a small pore, thereby thoroughly avoiding the black core defect generated by closed pores. The tungsten and copper phases of the prepared composite material respectively form a firm and communicated three-dimensional network, so that the unification of high conductivity (more than or equal to 60 percent IACS), high toughness (hardness more than or equal to 100 HB) and excellent arc ablation resistance is realized in a radical synergistic way, and the long-standing limit of 'performance impossible triangle' is effectively broken through. And the process integration level is high, the environment is protected, the strengthening effect is obvious, and the process simplification, the environment-friendly strengthening and the performance improvement are realized at one time. The method has the advantages of outstanding raw material and process cost, wide industrialization prospect and perfect balance of the relationship between the three of high performance, designability and mass producibility.

Inventors

  • XIE KUN
  • ZHU ZHONGQI
  • XIA PENGCHENG
  • CAO MEIQING
  • YUE LIJIE

Assignees

  • 山东科技大学

Dates

Publication Date
20260505
Application Date
20260113

Claims (10)

  1. 1. The preparation method of the tungsten copper-infiltrated composite material is characterized by comprising the following steps of: (1) The preparation of the mixture comprises the following raw materials of tungsten powder, a binder and/or a stabilizer; Mixing the raw materials to form uniform slurry or paste; (2) Preparing and forming a prefabricated material, wherein the prefabricated material is a unit body with different geometric shapes, and the slurry or paste in the step (1) is processed into the unit body with the geometric shapes, wherein the preset geometric shapes comprise spherical shapes, rod shapes or tubular shapes; (3) Assembling a blank, namely filling at least one prefabricated material with a preset geometric shape into the die according to a preset mode as a basic unit, and assembling to form the blank with a macroscopic design; (4) Degreasing, sintering and infiltration, namely placing a die with a blank body into a degreasing sintering furnace, heating to 100-1000 ℃ under a protective atmosphere, preserving heat, heating and decomposing a binder, gasifying, taking away by carrier gas, leaving tungsten powder particles and/or a stabilizer, and degreasing; continuously heating to 1000-2400 ℃ in a protective atmosphere, preserving heat, forming firm metallurgical bonding between tungsten powder particles through atomic diffusion, shrinking and strengthening a green body, and finally forming a tungsten skeleton; and (3) putting the sintered tungsten skeleton into a infiltration furnace together with a sufficient amount of copper blocks or copper sheets, heating the tungsten skeleton and the copper sheets together under a protective atmosphere, rapidly and uniformly filling all pores along a pre-designed through pore network in the tungsten skeleton under the action of capillary force, and cooling to obtain a compact tungsten copper infiltration composite material billet with mutually interweaved tungsten and copper phases.
  2. 2. The preparation method of the tungsten-copper-impregnated composite material according to claim 1 is characterized in that the average particle size of tungsten powder is 0.1-20 microns, and the binder is one of the following two types: a thermoplastic binder system comprising at least two of paraffin, high density polyethylene, polypropylene, stearic acid, polystyrene; A solution/slurry binder system comprising at least one of paraffin, 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, and the dispersion system is subjected to spray drying to obtain fine powder with fluidity; wherein the main material accounts for 10-50% of the stabilizer in mass fraction, and the auxiliary material accounts for 50-90% of the stabilizer in mass fraction; the main material is at least one selected from functional metal powder, functional metal compound powder, metal salt powder and low-dimensional carbon material; the auxiliary material is at least one selected from polyvinylpyrrolidone, polymethyl methacrylate, dimethylformamide, polyvinyl alcohol, ethanol and water; 30-70% of adhesive, 0-1% of stabilizer and the balance of tungsten powder.
  3. 3. The method for preparing the tungsten-copper-infiltrated composite material according to claim 2, wherein the functional metal powder, the metal compound powder and the 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 oxides, nitrides, carbides, nitrates, carbonates and sulfates thereof, and the low-dimensional carbon material is graphene or carbon nanotubes.
  4. 4. The method for preparing the tungsten-copper-impregnated composite material according to claim 3, wherein when a class-A thermoplastic binder system is used, an internal mixer is adopted to carry out hot mixing on the tungsten powder, the class-A binder and the stabilizer at the temperature of 100-300 ℃ to obtain a well-plasticized slurry; When using a class B solution/slurry binder system, the tungsten powder, the class B binder, and the stabilizer are mixed at room temperature or a suitable temperature using a planetary mixer or stirring device to form a uniform slurry or paste.
  5. 5. The method for preparing the tungsten-copper-infiltrated composite material according to claim 1, wherein the preparation method of the spherical prefabricated material comprises the steps of processing the mixture into spherical unit bodies with the particle size of 50-1000 microns through a granulating technology; The granulating technology is that the extrusion is round after cutting, and the specific steps include: S1, continuously extruding a well-plasticized feed through an extruder die head; s2, cutting the extruded strip material into small blocks similar to cubes by using a cutter; S3, enabling the small material blocks to fall into a high-speed rotary rounding machine, rolling, colliding and rounding edges and corners under the action of centrifugal force and friction force to form a spherical-like prefabricated material.
  6. 6. The method for preparing the tungsten-copper-impregnated composite material according to claim 1, wherein the preparation method of the rod-shaped preform comprises extruding a feed through a die head into filaments with diameters of 50-1000 microns, cutting the filaments into an adaptive length according to requirements, and controlling the ratio of a traction speed to an extrusion speed to enable the extruded filaments to form a straight rod or a spiral special-shaped rod-shaped preform.
  7. 7. The method for preparing the tungsten-copper-infiltrated composite material according to claim 1, wherein the tubular prefabricated material is of a cladding type structure, and the preparation method comprises the steps of uniformly cladding a feed on the surface of a core material by adopting a coaxial cladding extrusion technology to form a composite wire of a sheath-core structure, and cutting the composite wire into an adaptive length; The coaxial cladding extrusion technology specifically comprises the following steps: s1, enabling a core material to pass through an axial through hole in the center of a screw of an extruder and guide the core material to a die head; S2, enabling the heated and plasticized feed to be converged with the core material at the die head under the pushing of the screw rod, and uniformly wrapping the feed on the periphery of the core material to form a composite wire; s3, pulling the composite wire to advance at a controllable speed through a tractor, and controlling the thickness of a coating layer to be 50-1000 micrometers by adjusting the matching of the traction speed and the extrusion speed to form a linear or non-linear tubular prefabricated material; Wherein the core material is a metal wire or a decomposable polymer wire with an adaptive diameter.
  8. 8. The method for preparing a tungsten-impregnated copper composite material according to claim 1, wherein the green body is a green body with bimodal or multimodal pore distribution, a functionally graded material green body, a tubular passage green body or a green body with spiral passages inside.
  9. 9. The method for preparing the tungsten-copper-impregnated composite material according to claim 1, wherein in the step (4), the protective atmosphere is vacuum, nitrogen, argon, hydrogen or argon-hydrogen mixed gas, the temperature is kept for 2-20 hours during degreasing, 0.1-3 hours during sintering, and the temperature is kept for 1-10 hours after heating to 1100-1400 ℃ during infiltration.
  10. 10. A tungsten copper-infiltrated composite material prepared by the method of any one of claims 1-9.

Description

Tungsten copper-infiltrated composite material and preparation method thereof Technical Field The invention belongs to the technical field of composite material preparation, and particularly relates to a tungsten copper-infiltrated composite material and a preparation method thereof. Background Tungsten-copper composite (W-Cu) is a "pseudoalloy" in which tungsten (W) having a high melting point, high hardness, and low coefficient of thermal expansion is combined with copper (Cu) having high electrical conductivity, high thermal conductivity, and good ductility. The unique performance combination makes the composite material an irreplaceable key material under extreme working conditions, and is widely applied to the fields of electricians, electronics and high-end equipment. In the high-end applications described above, particularly in ultra-high voltage electrical contacts and electromagnetic rails, tungsten copper materials are required to operate stably in extreme environments of "high current, strong arc, high friction, high load". This requires that the material meet three core performance criteria, high strength/toughness, high electrical/thermal conductivity, excellent arc ablation resistance, simultaneously. However, because tungsten and copper have extremely large physical differences and are mutually insoluble, the three performance indexes show a strong mutual restriction relation in the prior art, and a 'performance impossible triangle' of the WCu composite material is formed: the strength is improved by increasing the content and continuity of the hard tungsten phase, but this breaks the conductive network of copper, reducing conductivity/thermal conductivity. The conductivity is improved by increasing the copper phase content and ensuring the three-dimensional connection of the copper phase, but the strengthening effect of tungsten is weakened, and the strength is reduced. The arc ablation resistance is improved, a special microstructure is needed to stabilize the arc and reduce the ablation, but the arc ablation is often in conflict with the arc ablation resistance and the ablation resistance. Therefore, how to cooperatively improve the strength, the conductivity and the ablation resistance of the tungsten copper material through innovative material design and preparation processes and break the 'performance impossible triangle' is a core technical problem facing the current person skilled in the art. In order to solve the contradiction, researchers explore from two core ideas, namely, optimizing the micro-structure and macro-structure distribution of tungsten/copper two phases and adding an anti-ablation stabilizer into the material. (1) The technical scheme of optimizing the tungsten-copper two-phase structure is as follows. The core aim is to construct an ideal 'bicontinuous interpenetrating network structure' in the tungsten-copper composite material, namely a high-strength tungsten framework and a conductive copper network are mutually interwoven and respectively continuous. The key point is that a tungsten skeleton with three-dimensional through holes and controllable size is prepared in advance. The main method comprises the following steps: The infiltration method (traditional mainstream technology) comprises the steps of firstly pressing tungsten powder into a blank and sintering to form a tungsten skeleton with pores inside, then at high temperature (higher than the melting point of copper by 1083 ℃), penetrating molten copper into the pores of the tungsten skeleton by virtue of capillary force, and cooling to obtain the compact WCu composite material. Conventional infiltration methods rely on random distribution of tungsten particles to provide porosity and WCu composites that are not sufficiently conductive. The powder metallurgy sintering method is that tungsten powder and copper powder are directly and evenly mixed, pressed and formed, and then sintered for a long time at high temperature (usually slightly lower than the melting point of copper), so that powder particles are combined into the WCu composite material through atomic diffusion. Although the sintering method can prepare the composite material with high copper content, solid phase sintering leads to low density, and the conductivity is improved to a limited extent, but the toughness is greatly sacrificed. Advanced framework preparation methods (developed to improve traditional methods) do not rely on random stacking of tungsten powder to form pores, but rather active "pore-forming". Such as a stencil/paste process, an additive manufacturing (3D printing) process, a fiber/wire skeleton process. (2) The technical proposal of adding an ablation resistant third phase (stabilizer). Trace amounts of high melting point, high stability particles, such as nano lanthanum oxide (La 2O3), yttrium oxide (Y 2O3), aluminum oxide (Al 2O3) or graphene, are added to tungsten or copper substrates to stabilize the arc against excessive ab