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CN-122012963-A - High-temperature titanium alloy and preparation method thereof

CN122012963ACN 122012963 ACN122012963 ACN 122012963ACN-122012963-A

Abstract

The invention provides a high-temperature titanium alloy and a preparation method thereof, and belongs to the technical field of high-temperature titanium alloys. According to the invention, sn is taken as a core regulating element, and high-density dislocation and subgrain boundary structures are introduced into the alloy by precisely regulating the Sn content (the addition amount is 10.0-12.0 wt%) and matching with a uniform thermal deformation process, so that the diffusion and uniform distribution of Al and Sn elements are obviously promoted, and an ordered structure is stably formed in a primary equiaxial alpha phase. Through ingredient design and process cooperative regulation, a Ti 3 (Al, sn) characteristic structure with optimal Al/Sn atomic ratio is obtained, and the structure is a key microscopic mechanism for realizing the high-temperature strength, good tissue stability and excellent oxidation resistance of the alloy at 700 ℃. Compared with the conventional high-temperature titanium alloy preparation process, the invention realizes synchronous improvement of high-temperature mechanical property and oxidation resistance through directional collaborative design of components, tissues and properties.

Inventors

  • ZHANG XINYU
  • ZHAO ZIBO
  • LIU YUJING
  • ZHANG JUNSONG
  • LIU RIPING

Assignees

  • 燕山大学
  • 昱华先进材料科技(陕西)有限公司

Dates

Publication Date
20260512
Application Date
20260319

Claims (10)

  1. 1. The preparation method of the high-temperature titanium alloy is characterized by comprising the following steps of: (1) The raw materials are weighed according to the mass percentage of 5.8+/-0.1 percent of Al, 2.5+/-0.05 percent of W, 0.4+/-0.05 percent of Si, 0.05+/-0.01 percent of C, 10.0-12.0 percent of Sn and the balance of Ti and unavoidable impurities, the raw materials are mixed and pressed into electrodes, and alloy cast ingots are prepared through vacuum consumable arc melting; (2) Sequentially performing high-temperature forging of a beta phase region, forging of a beta phase transformation point and forging of an alpha+beta phase region on the alloy ingot, and performing air cooling after final forging; (3) Carrying out surface treatment and preheating treatment on the forging blank obtained in the step (2), then carrying out heat preservation at 40-60 ℃ below the beta transformation point, then carrying out multi-pass finish forging, wherein the total deformation is 50% -60%, and carrying out air cooling and furnace returning heat preservation between passes to obtain a bar after finish forging; (4) And carrying out solution treatment and aging treatment on the bar after finish forging to obtain the high-temperature titanium alloy.
  2. 2. The method for preparing high temperature titanium alloy according to claim 1, wherein in the step (2), the step of high temperature forging in the beta phase region comprises heating the alloy ingot to 1160-1200 ℃, preserving heat for 8-10 hours, forging by upsetting and pulling, wherein the upsetting deformation is not less than 50%, the final forging temperature is not less than 980 ℃, and air cooling after forging; The forging step above the beta transformation point comprises the steps of heating a blank to 30-60 ℃ above the beta transformation point, preserving heat for 8-10h, carrying out continuous two-upsetting and two-drawing forging, wherein the upsetting deformation is not lower than 50%, the final forging temperature is not lower than 900 ℃, and carrying out air cooling after forging; the step of forging the alpha and beta two-phase region comprises the steps of heating a blank to 40-80 ℃ below the beta phase transition point, preserving heat for 8-10h, forging for 2-3 times by upsetting and pulling, wherein the upsetting deformation is 40% -45%, the final forging temperature is not lower than 800 ℃, and air cooling after forging.
  3. 3. The method for preparing the high-temperature titanium alloy according to claim 2, wherein the high-temperature forging drawing mode of the beta phase region is tetragonal drawing, the single drawing deformation is less than 20%, the deformation rate is 0.005-0.015s -1 , the drawing modes of the above-beta phase transformation point forging and the alpha+beta two-phase region forging are eight-way drawing, the single drawing deformation is less than 20%, and the deformation rates are 0.005-0.015s -1 and 0.008-0.02s -1 respectively.
  4. 4. The method of producing high temperature titanium alloy according to claim 1, wherein in step (1), the number of times of vacuum consumable arc melting is 3.
  5. 5. The method for producing a high temperature titanium alloy according to claim 1, wherein in the step (3), the pre-heating treatment is to pre-heat the surface-treated billet to 500 to 650 ℃ and keep the temperature for 1 to 2 hours.
  6. 6. The method for preparing the high-temperature titanium alloy according to claim 1, wherein in the step (3), in the multi-pass precision forging, after each pass of forging is completed, the blank is air-cooled for 2-5min, and is returned to a heating furnace to keep the temperature below a beta transformation point by 20-40 ℃ and then subjected to the next pass of forging, wherein the forging frequency is 200-400 times/min, and the single pass deformation is 5-35%.
  7. 7. The method for preparing the high-temperature titanium alloy according to claim 6, wherein the multi-pass precision forging specifically comprises 380 times/min of first-pass forging frequency, 8-15% of deformation, 200-300 times/min of second-pass forging frequency, 20-30% of deformation, 220-300 times/min of third-pass forging frequency, 15-20% of deformation, 400 times/min of fourth-pass forging frequency and 5-10% of deformation.
  8. 8. The method for producing a high-temperature titanium alloy according to claim 1, wherein in the step (4), the solution treatment is air-cooling after heat preservation for 2 hours at 15-30 ℃ below the beta transformation point of the bar, and the aging treatment is air-cooling after heat preservation for 2 hours at 700 ℃.
  9. 9. A high temperature titanium alloy prepared according to the preparation method of any one of claims 1 to 8.
  10. 10. The high temperature titanium alloy of claim 9, wherein said high temperature titanium alloy has a primary equiaxed alpha phase of Ti 3 (Al, sn) ordered phase and an Al/Sn atomic ratio of 0.66 to 1.56.

Description

High-temperature titanium alloy and preparation method thereof Technical Field The invention belongs to the technical field of high-temperature titanium alloy, and particularly relates to a high-temperature titanium alloy and a preparation method thereof. Background Titanium alloy has become a key structural material in the fields of aerospace, advanced power and the like because of the advantages of low density, high specific strength, excellent corrosion resistance and the like, and particularly has an irreplaceable position in the air compressor blade, the casing and the high Wen Chengli component of an air engine. With the development of aerospace equipment to the high thrust weight ratio and long service life, the service temperature of the component is continuously improved, and more stringent requirements are put on the comprehensive mechanical properties of the titanium alloy under the medium-high temperature condition. However, the conventional titanium alloy often faces the problem of synchronous reduction of strength and plasticity at high temperature, the bearing capacity of the component is reduced due to insufficient high-temperature strength, and the risk of crack initiation and instability propagation is increased due to insufficient plasticity, so that safe and reliable application at higher temperature is severely restricted. Therefore, the system improves the toughness of the titanium alloy under the high-temperature condition, realizes the improvement of the comprehensive mechanical property, is a key problem for improving the service temperature upper limit of the titanium alloy, and has remarkable engineering value and strategic significance for the application of the titanium alloy in the aerospace field. The ordered phase can significantly improve the high temperature strength and creep resistance of the titanium alloy, but also tends to cause the high temperature plasticity and fracture toughness to be reduced. In order to improve the high-temperature mechanical properties of the titanium alloy, the formation of ordered phases is regulated and controlled by adopting a multielement cooperative reinforcement design. Among these, al is an important α -stable element, and increases the α -phase strength by solid solution strengthening, but excessive amounts promote the formation of ordered phases, resulting in a decrease in alloy plasticity. Sn is also an alpha stable element, can regulate and control ordered behaviors to a certain extent, but has a relatively complex effect in a Ti-Al matrix, on one hand, different contents of Sn can form various structures, so that the final phase composition and microscopic morphology of the alloy are difficult to control accurately, obvious fluctuation and instability of the alloy performance occur, on the other hand, a Ti-Al-Sn system is actually a complex solid solution combined with a locally ordered crystal structure, is obviously influenced by Al/Sn occupation competition, O and other light elements, is difficult to describe accurately by a single stoichiometric model, and causes long-term dependence on a trial-and-error method in alloy design, and the definite theoretical guidance and structure-performance correspondence is lacking. Therefore, the diversity and uncertainty of the structure make precise regulation and control of ordered phases through component design, so that great challenges are faced to cooperatively improving the high-temperature strength and plasticity of the alloy, and the technical bottleneck to be solved in the field is also formed. Disclosure of Invention In order to solve the technical problems, the invention provides a high-temperature titanium alloy and a preparation method thereof, wherein Sn is used as a core regulating element, the directional control of high-temperature strength and oxidation resistance of the alloy is realized by accurately regulating the content of Sn (the addition amount is 10.0-12.0%), a brand new technical idea is provided for the component optimal design and engineering application of the high-temperature titanium alloy, the distribution of Al and Sn is obviously uniform through a uniform thermal deformation process design, a large number of dislocation and subgrain boundaries are introduced into an alpha phase, favorable nucleation positions are provided for the ordered phase, and the solid solution and cooling/aging processes provide enough thermal activation conditions for short-range diffusion and occupation rearrangement of Al/Sn in the alpha crystal lattice, so that the primary alpha phase is promoted to realize the ordered priority. The obtained Ti 3 (Al, sn) structure containing the optimal Al/Sn atomic ratio ensures that the alloy obviously improves the phase transition temperature and the high-temperature mechanical property, has better oxidation resistance and can effectively reduce the cost of raw materials. In order to achieve the above purpose, the present invention provides