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CN-121976190-A - Fine-grained refractory metal block based on liquid metal, and preparation method and application thereof

CN121976190ACN 121976190 ACN121976190 ACN 121976190ACN-121976190-A

Abstract

The invention relates to the technical field of refractory metal materials, in particular to a fine-grain refractory metal block based on liquid metal, and a preparation method and application thereof. The preparation method comprises the steps of 1) preparing refractory metal blanks from refractory metal powder through uniaxial compression molding, uniformly coating liquid metal on the surfaces of the blanks, performing heat preservation and infiltration treatment under a protective gas atmosphere, cooling to room temperature to obtain precursor samples, and 2) performing rapid temperature rise and fall treatment on the precursor samples by a Joule heating method, and then performing acid leaching, washing, centrifugation and drying on the treated samples. According to the preparation method disclosed by the invention, a liquid metal induced bond softening strategy is adopted, the refractory metal is rapidly sintered and densified at a temperature far lower than that of a traditional method by utilizing a liquid metal medium, meanwhile, a fine crystal structure is maintained, the universality and the expandability of the preparation method are good, the liquid metal can be completely removed without residues, and the prepared refractory metal block can meet the extreme environmental application requirements.

Inventors

  • FU LEI

Assignees

  • 安徽大学

Dates

Publication Date
20260505
Application Date
20260213

Claims (10)

  1. 1. A method for the low temperature production of a fine-grained refractory metal block based on liquid metal, characterized in that the production method comprises the steps of: 1) Carrying out uniaxial compression molding on refractory metal powder to obtain refractory metal blanks, uniformly coating liquid metal on the surfaces of the blanks, carrying out heat preservation permeation treatment in a protective gas atmosphere, and cooling to room temperature to obtain precursor samples; 2) Carrying out rapid temperature rise and fall treatment on the precursor sample by adopting a Joule heating method, and then carrying out acid leaching, washing, centrifugal separation and drying on the treated sample to obtain a fine-grain refractory metal block; Wherein the refractory metal powder is selected from any one of pure metal powders of tungsten, rhenium, molybdenum, tantalum, niobium, titanium, vanadium, chromium, zirconium and hafnium; The grain size of the refractory metal powder is 200 nm-1 mu m; The liquid metal is selected from pure metal of any one of gallium, indium, tin, bismuth and zinc or alloy of any several compositions.
  2. 2. The method according to claim 1, wherein in step 1), the mass ratio of the refractory metal powder to the liquid metal is 1-20:0.1.
  3. 3. The method according to claim 1 or 2, wherein in step 1), the uniaxial compression molding is performed under pressure of 100 to 1000mpa by using an electrohydraulic pressure tester, the dwell time is 15 to 25 min, and the thickness of the obtained refractory metal green body is 0.01 to 100mm, preferably 0.01 to 40mm.
  4. 4. The preparation method according to any one of claims 1 to 3, wherein in the step 1), the conditions of heat preservation and permeation include heating to 500-800 ℃ at a heating rate of 3-8 ℃ per min under a protective gas, heat preservation for 1-4 hours, cooling to 200-500 ℃ at a cooling rate of 8-12 ℃ per min, and heat preservation for 1-4 hours; Preferably, the shielding gas is hydrogen and/or argon, preferably a mixed gas of argon and hydrogen, wherein the flow rate of the argon is 150-250 sccm, and the flow rate of the hydrogen is 20-70 sccm.
  5. 5. The production method according to any one of claims 1 to 4, wherein in step 2), the joule heating method is selected from one of a carbon thermal shock method, a laser sintering method, and an arc sintering method; Preferably, the carbon thermal shock method comprises the following steps of taking a carbon-based material as a heating carrier and an energy transmission medium under the protection of inert gas, rapidly raising the temperature to 600-1000 ℃ at a voltage rate of 1-3V/s, and preserving the temperature for 2-15 min; Preferably, the inert gas is argon and/or nitrogen; preferably, the carbon-based material is selected from one or more of carbon felt, carbon paper and carbon cloth.
  6. 6. The method according to any one of claims 1 to 5, wherein in step 2), the acid leaching conditions include immersing the sample in a hydrochloric acid solution having a concentration of 1 to 5mol/L at 15 to 30 ℃ for 2 to 8 hours; washing the acid leached sample with deionized water and absolute ethyl alcohol for 3-5 times; The centrifugation conditions comprise a rotation speed of 3000-5000 rpm and a time of 5-10 min.
  7. 7. The method according to any one of claims 1 to 6, wherein the drying conditions include a temperature of 50 to 95 ℃ for 4 to 6 hours under vacuum.
  8. 8. A fine-grained refractory metal block produced by the low-temperature production method of a fine-grained refractory metal block based on liquid metal as claimed in any one of claims 1 to 7.
  9. 9. The fine-grained refractory metal block according to claim 8, wherein the density of the fine-grained refractory metal block is greater than or equal to 95%.
  10. 10. Use of a fine-grained refractory metal block according to claim 9 for the preparation of high temperature materials and micro-nano electronic functional materials.

Description

Fine-grained refractory metal block based on liquid metal, and preparation method and application thereof Technical Field The invention relates to the technical field of refractory metal materials, in particular to a fine-grain refractory metal block based on liquid metal, and a preparation method and application thereof. Background Severe working environments in the fields of aerospace, nuclear energy and the like place stringent requirements on structural materials, not only are materials required to have excellent mechanical properties, but also to be resistant to high temperatures, corrosion and irradiation damage, and most materials have failed or melted before reaching the working temperature. Compared with widely used nickel-based superalloys, the refractory metals can still maintain stability and reliability under extreme high temperature and severe environments by virtue of higher melting point, more excellent high-temperature strength and other performances. The development of refractory metal structural materials with fine grains, uniform microstructure and excellent mechanical properties not only meets the key requirements of increasingly higher service temperature and complex stress conditions, but also provides important support for the design and high-end application of future high-temperature material systems. The presence of strong metal bonds in the crystal structure of refractory metals, which are essentially driven by the high electron density, gives refractory metals excellent thermal and mechanical stability, but at the same time presents considerable challenges for the processing of such materials. Conventional processing and manufacturing methods have been used to produce various refractory metal products. However, these structural materials currently available for industrial and micro/nano-electronic applications remain limited. This is mainly because the melting temperature of the refractory metal exceeds 2000 ℃ and even 3000 ℃, and conventional metallurgical methods such as melt casting, hot press sintering, two-step sintering and spark plasma sintering require a long time of high temperature sintering process to partially achieve densification of the refractory metal block. However, high temperature long-time sintering is extremely liable to cause deterioration of microstructure, particularly coarsening of crystal grains, thereby seriously deteriorating the properties of the material. The root cause is that densification and grain growth are driven by capillary forces, and their thermal activation kinetics typically have similar activation energies and are therefore difficult to control separately. In order to solve the problem of coarsening of grains, attempts are made in the industry to prepare refractory metal blocks by adopting a room temperature severe plastic deformation technology, such as high-pressure torsion, equal-channel angular extrusion, surface mechanical abrasion and the like, and the technology can refine grains to a certain extent and introduce high-density dislocation, but the refractory metal is extremely poor in room temperature plasticity, cracks are easily generated in the processing process, and the development of a fine-structure refractory metal material is limited. Therefore, a low-temperature and rapid refractory metal block preparation method with a fine-grain structure is developed, the high densification and fine-grain structure of the refractory metal block are achieved under the mild process conditions, the limitations of the traditional metallurgical method and plastic processing technology are broken through, and the method has important significance for promoting the application of the refractory metal material in the fields of high-temperature materials, micro-nano electronic functional materials and the like in extreme environments. Disclosure of Invention The invention aims to solve the problems that high-temperature sintering grains are coarsened, room-temperature plastic deformation is easy to crack and high densification and fine-grain structure cannot be achieved at the same time in the preparation of refractory metal blocks in the prior art, so that the fine-grain refractory metal blocks based on liquid metal, and a preparation method and application thereof are provided. In order to achieve the above object, in a first aspect, the present invention provides a low temperature preparation method of a fine-grained refractory metal block based on liquid metal, the preparation method comprising the steps of: 1) Carrying out uniaxial compression molding on refractory metal powder to obtain refractory metal blanks, uniformly coating liquid metal on the surfaces of the blanks, carrying out heat preservation permeation treatment in a protective gas atmosphere, and cooling to room temperature to obtain precursor samples; 2) Carrying out rapid temperature rise and fall treatment on the precursor sample by adopting a Joule heating method, and then