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CN-121992235-A - High tissue uniformity Ti2AlNb alloy and powder metallurgy preparation method and application thereof

CN121992235ACN 121992235 ACN121992235 ACN 121992235ACN-121992235-A

Abstract

The invention discloses a Ti 2 AlNb alloy with high tissue uniformity and a powder metallurgy preparation method and application thereof, belonging to the technical field of metal powder processing. The preparation method of the powder metallurgy comprises the steps of preparing spherical Ti 2 AlNb pre-alloy powder and reinforcing phase powder with lamellar morphology, respectively carrying out stress relief annealing treatment on the spherical Ti 2 AlNb pre-alloy powder and the reinforcing phase powder, mixing, then sequentially carrying out wet high-energy ball milling treatment, drying, sieving, spark plasma sintering and dual heat treatment to prepare the high-structure-uniformity Ti 2 AlNb alloy, and solving the technical problems that when the Ti 2 AlNb alloy is prepared by the existing powder metallurgy combined spark plasma sintering technology, due to high sintering temperature, too fast cooling speed and inconsistent element diffusion rate, al is concentrated in grain boundaries and Nb in the grains, the alloy structure is uneven, and brittle alpha 2 phases are easy to separate out in an Al-rich area in the subsequent heat treatment, and the toughness of the material is damaged.

Inventors

  • CHENG CHAO
  • ZHANG BOHUA
  • ZHANG SHUAI
  • WANG ZHONG
  • Jia Kelun
  • LIU YUJING
  • ZHAO ZIBO

Assignees

  • 昱华先进材料科技(陕西)有限公司

Dates

Publication Date
20260508
Application Date
20260128

Claims (10)

  1. 1. The powder metallurgy preparation method of the Ti 2 AlNb alloy with high tissue uniformity is characterized by comprising the following steps of: Mixing titanium powder, alNb intermediate alloy powder and AlMo intermediate alloy powder, and then performing first high-energy ball milling treatment to obtain spherical Ti 2 AlNb pre-alloy powder; Mixing TiMo intermediate alloy powder and NbTi intermediate alloy powder, and then performing secondary high-energy ball milling treatment to obtain reinforcing phase powder with a lamellar morphology, wherein the TiMo intermediate alloy powder accounts for 15% -30% of the mass of the reinforcing phase powder, and the length-diameter ratio of the reinforcing phase powder is (3-5): 1; Respectively carrying out stress relief annealing treatment on the spherical Ti 2 AlNb prealloyed powder and the reinforced phase powder, and then cooling to obtain annealed spherical Ti 2 AlNb prealloyed powder and annealed reinforced phase powder; Mixing annealed spherical Ti 2 AlNb pre-alloyed powder and annealed reinforcing phase powder, and then sequentially performing wet high-energy ball milling treatment, drying and sieving to obtain Ti 2 AlNb-based composite material powder, wherein the annealed reinforcing phase powder accounts for 5% -10% of the mass of the Ti 2 AlNb-based composite material powder; And sequentially performing spark plasma sintering and dual heat treatment on the Ti 2 AlNb-based composite material powder to obtain the Ti 2 AlNb alloy with high tissue uniformity.
  2. 2. The powder metallurgy preparation method of the high-tissue-uniformity Ti 2 AlNb alloy, which is characterized in that the particle diameter of titanium powder is 75-150 microns, the mass ratio of Al element in the components of the AlNb master alloy powder is 20-30%, the particle diameter is 80-120 microns, the mass ratio of Al element in the components of the AlNo master alloy powder is 80-90%, the particle diameter is 80-100 microns, and the spherical Ti 2 AlNb master alloy powder comprises 22% of Al, 24% of Nb and 0.45-0.55% of Mo, and the balance of Ti and impurity elements in terms of atomic percentage; The mass ratio of Mo element in the TiMo intermediate alloy powder is 25% -30%, the particle diameter is 100-120 mu m, the mass ratio of Nb element in the NbTi intermediate alloy powder is 40% -50%, and the particle diameter is 100-150 mu m.
  3. 3. The method for preparing the high-tissue-uniformity Ti 2 AlNb alloy by powder metallurgy according to claim 1, wherein in the stress relief annealing treatment, the atmosphere is argon atmosphere, the temperature is 750-800 ℃ and the time is 30-60 min.
  4. 4. The method for preparing the high-structure-uniformity Ti 2 AlNb alloy by powder metallurgy according to claim 1, wherein the hard alloy balls used in the first high-energy ball milling treatment, the second high-energy ball milling treatment and the wet high-energy ball milling treatment are made of ZrO 2 , the diameter of the small balls is 3mm, the diameter of the medium balls is 5mm, the diameter of the large balls is 8mm, and the material of the ball milling tank is made of titanium-based alloy.
  5. 5. The powder metallurgy preparation method of the high-tissue-uniformity Ti 2 AlNb alloy is characterized in that in the first high-energy ball milling treatment, the ball material ratio is (8-10) 1, the rotating speed is 400-450 r/min, the total ball milling time is 8-10 h, intermittent operation is adopted, each time of 30-45 min is carried out, 5-10 min is suspended, the ball milling time is recycled, and the ball, the middle ball and the large ball account for 45-50%, 25-30% and 20-30% by mass percent respectively; In the second high-energy ball milling treatment, the ball-material ratio is (20-25) 1, the rotating speed is 500-800 r/min, the total ball milling time is 5-8 h, intermittent operation is adopted, each time of 30-45 min is operated, 5-10min is suspended, the ball milling time is recycled, and the ball, the ball and the middle ball and the big ball account for 5-10%, 25-30% and 60-70% in percentage by mass respectively; And adding 3-5% of process control agent in mass percent in the second high-energy ball milling treatment, wherein the process control agent is stearyl alcohol.
  6. 6. The powder metallurgy preparation method of the high-tissue-uniformity Ti 2 AlNb alloy according to claim 4, wherein the medium subjected to wet high-energy ball milling treatment is absolute ethyl alcohol, the mass ratio of the medium to the total mass of the annealed spherical Ti 2 AlNb pre-alloyed powder and the annealed reinforcing phase powder is (8-10): 1, the ball-to-material ratio is (3-5): 1, the rotating speed is 300 r/min-400 r/min, the ball milling time is1 h-3 h, and the percentages of pellets, middlings and macrospheres are 60% -65%, 20% -25% and 10% -20% respectively according to the mass percentages; The temperature of the drying is 60-80 ℃.
  7. 7. The method for preparing high-structure-uniformity Ti 2 ainb alloy powder metallurgy according to claim 1, wherein the technological parameters of spark plasma sintering are as follows: Heating to 825-960 ℃ at a heating rate of 80-100 ℃ per minute, heating to 1100-1200 ℃ at a heating rate of 10-15 ℃ per minute, maintaining sintering pressure of 130-150 MPa and vacuum degree of less than or equal to 1X 10 -3 Pa at the target sintering temperature of 1100-1200 ℃, preserving heat for 15-30 min, reducing the sintering pressure to 50-70 MPa after heat preservation is finished, and cooling by adopting a circulating water cooling mode.
  8. 8. The powder metallurgy preparation method of the high-tissue-uniformity Ti 2 AlNb alloy is characterized by comprising a first reheating treatment and a second reheating treatment which are sequentially carried out, wherein the temperature of the first reheating treatment is 20-30 ℃ above the phase transition points of the three-phase areas of B2, O and alpha 2 , the heat preservation time is 2-4 hours, the cooling mode is oil cooling, the time taken from the first reheating treatment to the cooling box is less than 30 seconds, the temperature of the second reheating treatment is 770-810 ℃, the heat preservation time is 12-24 hours, and the cooling mode is air cooling.
  9. 9. The high-structure-uniformity Ti 2 AlNb alloy is characterized in that the high-structure-uniformity Ti 2 AlNb alloy is prepared by adopting the powder metallurgy preparation method of the high-structure-uniformity Ti 2 AlNb alloy according to any one of claims 1 to 8, wherein the structure of the high-structure-uniformity Ti 2 AlNb alloy consists of a B2 matrix phase, an O phase and an alpha 2 phase, wherein the O phase and the alpha 2 phase are in a lath shape and are uniformly distributed, and the structure morphology of the edge area, the 1/2 position of the radius and the central area of the cross section of the high-structure-uniformity Ti 2 AlNb alloy is similar.
  10. 10. The use of a high structure uniformity Ti 2 ainb alloy in hot end components of an aerospace engine, wherein the high structure uniformity Ti 2 ainb alloy is prepared by a powder metallurgy preparation method of a high structure uniformity Ti 2 ainb alloy as defined in any one of claims 1 to 8.

Description

Ti 2 AlNb alloy with high tissue uniformity and powder metallurgy preparation method and application thereof Technical Field The invention belongs to the technical field of metal powder processing, and particularly relates to a high-tissue-uniformity Ti 2 AlNb alloy and a powder metallurgy preparation method and application thereof. Background As aerospace technology advances toward higher performance, more stringent requirements are placed on high temperature structural materials. The Ti 2 AlNb alloy is regarded as a potential material for replacing the traditional nickel-based superalloy because of the excellent specific strength, lower heat conductivity coefficient and excellent corrosion resistance, and especially meets the dual requirements of an aeroengine on light weight and high temperature performance. At present, ti 2 AlNb alloy is mainly prepared by a vacuum melting process. However, the melting point difference of Al and Nb elements in the alloy is large, the diffusion behavior is inconsistent, and the problems of macrosegregation and uneven structure are easily caused in the smelting process, so that the stability of the material performance is further affected. More importantly, the temperature of vacuum melting is far higher than the boiling point of Al element, which can cause serious burning loss of Al, further cause component runaway and microstructure deterioration, and lower the yield. Powder metallurgy technology is becoming an important way to replace traditional smelting processes due to its advantages in terms of component uniformity and microstructure control. The method is combined with a spark plasma sintering (SPARK PLASMA SINTERING, SPS) technology, so that coarsening of crystal grains can be effectively inhibited, and rapid densification preparation of the material is realized. Although in recent years, the introduction of a particulate reinforcing phase has become a common means of improving the performance of powder metallurgy titanium alloys. However, in the SPS process, due to high sintering temperature and high cooling speed, the alloy structure is often mainly a single B2 phase, and due to difference of element diffusion behaviors, al element is easy to be biased at a crystal boundary, nb element is easy to be enriched in crystal, so that the alloy structure is seriously uneven, and further, the brittle alpha 2 phase is induced to be separated out in the subsequent heat treatment, and the toughness of the material is damaged. Disclosure of Invention In order to overcome the defects of the prior art, the invention aims to provide the Ti 2 AlNb alloy with high tissue uniformity and the powder metallurgy preparation method and application thereof, and aims to solve the technical problems that when the Ti 2 AlNb alloy is prepared by adopting the existing powder metallurgy combined SPS technology, due to high sintering temperature, too fast cooling speed and inconsistent element diffusion rate, al is enriched in grain boundaries and Nb is enriched in grains, so that the alloy structure is uneven, and the brittleness alpha 2 phase is easy to separate out in an Al-enriched area in the subsequent heat treatment to damage the toughness of the material by introducing a novel lamellar reinforcing phase rich in beta stable elements to inhibit element segregation and combining with spark plasma sintering and a dual heat treatment technology. In order to achieve the above purpose, the invention is realized by adopting the following technical scheme: the invention provides a powder metallurgy preparation method of a Ti 2 AlNb alloy with high tissue uniformity, which comprises the following steps: Mixing titanium powder, alNb intermediate alloy powder and AlMo intermediate alloy powder, and then performing first high-energy ball milling treatment to obtain spherical Ti 2 AlNb pre-alloy powder; Mixing TiMo intermediate alloy powder and NbTi intermediate alloy powder, and then performing secondary high-energy ball milling treatment to obtain reinforcing phase powder with a lamellar morphology, wherein the TiMo intermediate alloy powder accounts for 15% -30% of the mass of the reinforcing phase powder, and the length-diameter ratio of the reinforcing phase powder is (3-5): 1; Respectively carrying out stress relief annealing treatment on the spherical Ti 2 AlNb prealloyed powder and the reinforced phase powder, and then cooling to obtain annealed spherical Ti 2 AlNb prealloyed powder and annealed reinforced phase powder; Mixing annealed spherical Ti 2 AlNb pre-alloyed powder and annealed reinforcing phase powder, and then sequentially performing wet high-energy ball milling treatment, drying and sieving to obtain Ti 2 AlNb-based composite material powder, wherein the annealed reinforcing phase powder accounts for 5% -10% of the mass of the Ti 2 AlNb-based composite material powder; And sequentially performing spark plasma sintering and dual heat treatment on the Ti 2 AlNb-based composite ma