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CN-117488156-B - Tungsten-based solid solution alloy and preparation method and application thereof

CN117488156BCN 117488156 BCN117488156 BCN 117488156BCN-117488156-B

Abstract

The invention relates to the technical field of solid solution alloy, and particularly discloses a tungsten-based solid solution alloy and a preparation method and application thereof. The invention prepares amorphous powder of Hf-Ta-B amorphous alloy by utilizing the characteristics of high homogenization, low melting point, high amorphous liquid phase capillary diffusion capability and the like, prepares the target alloy with pure W powder, uniformly mixes the raw material powder by ball milling, realizes the preparation of a W-based solid solution alloy sintered body at a certain sintering temperature (slightly higher than the Hf-Ta-B amorphous melting point) by a conventional hot-pressing sintering technology, and finally combines high-energy rate forging treatment to further optimize the composite solid solution strengthening effect of Hf and Ta and the fine crystal strengthening effect of B element, and finally obtains the fine crystal W-based thin solid solution alloy with good composition and tissue uniformity, so that the prepared alloy has high thermal conductivity and excellent high-temperature mechanical property.

Inventors

  • FENG FAN
  • LIAN YOUYUN
  • WANG JIANBAO
  • LIU XIANG

Assignees

  • 核工业西南物理研究院

Dates

Publication Date
20260505
Application Date
20231108

Claims (8)

  1. 1. The tungsten-based solid solution alloy is characterized by comprising a matrix and alloying elements dissolved in the matrix, wherein the matrix is metallic tungsten, and the alloying elements comprise hafnium, tantalum and boron; The chemical composition formula of the tungsten-based solid solution alloy is W 100-a (Hf,Ta,B) a in percentage by weight, wherein a is more than or equal to 1 and less than or equal to 3; the chemical composition formula of the hafnium, the tantalum and the boron is (Hf 100-b Ta b ) 98.5 B 1.5 ; wherein b is more than or equal to 10 and less than or equal to 70) in percentage by weight.
  2. 2. The method for producing a tungsten-based solid solution alloy according to claim 1, comprising the steps of: S1, preparing amorphous powder of alloying elements by combining arc melting with a melt atomization technology; S2, uniformly ball-milling and mixing the amorphous powder prepared in the step S1 with tungsten powder to form a mixed material; s3, preparing an alloy sintered body from the mixed material obtained in the step S2 through hot-pressing sintering; And S4, performing high-energy-rate forging treatment on the alloy sintered body obtained in the step S3.
  3. 3. The method of manufacturing according to claim 2, wherein step S1 comprises the steps of: S11, mixing alloying elements, placing the mixture in a non-consumable arc melting furnace, and introducing argon to perform non-consumable arc melting to prepare an alloy ingot; s12, crushing the alloy ingot prepared in the step S11, and then atomizing to prepare powder to obtain amorphous powder.
  4. 4. The preparation method of claim 3, wherein the working current of the smelting is 200-250A during non-consumable arc smelting, and the process of atomizing and pulverizing is as follows: Crushing an alloy ingot, putting the crushed alloy ingot into a graphite crucible, heating the alloy ingot to a temperature higher than the melting point of an alloying element, preserving the temperature for 2-5 min, and spraying and cooling the melted alloying element by adopting an atomization technology to obtain the spherical powder material.
  5. 5. The preparation method according to claim 2, wherein in the step S2, the ball ratio of ball milling and mixing is 1:5-1:10, the ball milling time is 2-5 h, and the rotational speed of the ball mill is 150-200 rpm.
  6. 6. The method according to claim 2, wherein in step S3, the pre-load pressure of the hot press sintering is 30MPa, the vacuum degree is 1 x 10 -2 Pa, the sintering temperature is 1750 to 1850 ℃, the sintering pressure is 70MPa, and the heat-preserving period is 60 to 180 min.
  7. 7. The method according to claim 2, wherein in step S4, the specific process of the high-energy-rate forging process is: The sintered blank is heated to 1600 ℃ and is preserved at 30min ℃ and then is rapidly placed in a high-speed pneumatic forging hammer machine for forging, the forging pressure is 40 MPa, and the forging direction is along the central axis direction of the cylindrical sintered blank.
  8. 8. Use of a tungsten-based solid solution alloy according to claim 1 in a magnetically confined fusion reactor, comprising for the preparation of a plasma component.

Description

Tungsten-based solid solution alloy and preparation method and application thereof Technical Field The invention relates to the technical field of solid solution alloys, in particular to a tungsten-based solid solution alloy and a preparation method and application thereof. Background The melting point of tungsten (W) is highest in all metals, young's modulus is only inferior to osmium (Os), high-temperature strength is high, and the tungsten (W) has special performances of high heat conductivity, low physical sputtering rate, low tritium retention, low neutron activation and the like, and is widely applied to engineering fields of illumination, aerospace, electronic packaging, military equipment, nuclear energy and the like. In future magnetically confined fusion stacks, advanced W alloys are the primary material for plasma-oriented components. In the fusion reactor operation process, the W alloy needs to bear high heat load caused by high-flux edge plasma, and is easy to crack under huge thermal stress, so that high-temperature strength is a key service performance index, and on the other hand, the heat conductivity of the W alloy is high so as to ensure that heat is rapidly transferred to a heat sink material, and recrystallization and even surface melting are avoided. Thus, high temperature strength and thermal conductivity are two key properties of advanced W alloys for use as fusion reactor high heat flux materials. The pure W has high ductile-brittle transition temperature, low recrystallization temperature, insufficient high-temperature strength and high-temperature creep resistance, and is difficult to meet the service performance requirements of plasma-oriented materials. Generally, the W-based solid solution alloy has good high-temperature structural stability, and solid solution strengthening is an important way for improving the high-temperature performance of the W material. However, neutron activation limits the application of Nb, mo, ni, co and other elements as solid solution components, while low neutron activation solid solution elements such as Zr, ti and the like are favorable for improving the W strength, and meanwhile, the ductile-brittle transition temperature of the material is also improved, so that the processing of parts is severely restricted. Of the known industrial W alloys, only W-Re alloys with high rhenium content (5 wt.%) have room temperature plasticity, but transmutation of Re in service environments can cause severe helium embrittlement, which is prohibited for fusion stacks. In particular, excessive addition of alloying elements such as Re can cause rapid reduction of thermal conductivity of the material, and the application of solid solution alloys such as W-Re as high-heat-flow materials in fusion stacks is severely limited. To obtain a tungsten-based solid solution alloy with high thermal conductivity and good high temperature strength, the total added content of solid solution elements must be tightly controlled (typically below 5 wt.%). Therefore, on one hand, low neutron activation additive elements with good solid solution strengthening effect are required to be selected, meanwhile, the preparation process is required to ensure that the additive elements with low content can be uniformly solid-dissolved into the W matrix, and the coarsening of material grains caused by related processes is required to be avoided. The research shows that the solid solution strengthening effect of hafnium (Hf) element on W material is obvious and superior to tantalum (Ta) and Re. Among the three solid solution elements, hf has the largest difference from W in terms of atomic radius, lattice parameter, melting point, density and the like, so that the solid solubility of Hf in W is also the smallest (4 at.%, 800-9 at.%,2512 ℃) and far lower than Re (30 at.%, 800-45 at.%,2890 ℃) and Ta (infinite mutual solubility). Recently Liu Shasha (effect of Hf microalloying on the structure and performance of tungsten-based surface to plasma materials. Nuclear industry southwest physical institute. 2020, west treatise) A W-Hf alloy with Hf (1.0 wt.% Hf) was prepared by spark plasma sintering (1850 ℃,3min,90MPa, small sample) and hydrogen sintering (to 2300 ℃ C., large sample) in combination with high energy rate forging techniques, and it was found from the test results that Hf in the alloy was mainly combined with O in the W matrix to form HfO 2, purifying the grain boundary impurities of the W matrix, improving the low temperature plasticity of the material, and at the same time, increasing the recrystallization temperature of the W material. It should be noted that the low-Hf content W-Hf alloy prepared by the prior art has HfO 2 oxide distributed mainly at the grain boundary of the W matrix, and cannot achieve sufficient solid solution of the added element Hf in the matrix W. This fact is also fully illustrative of how uniform solid solution of low amounts of Hf into the W matrix is very cha