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CN-121976137-A - Laser powder bed melting material-increasing nickel-based superalloy strong plastic synergistic lifting heat treatment process

CN121976137ACN 121976137 ACN121976137 ACN 121976137ACN-121976137-A

Abstract

The invention discloses a laser powder bed melting additive nickel-based superalloy plastic strengthening synergistic lifting heat treatment process, and relates to the technical field of metal post heat treatment. The printed test piece is heated, then air-cooled to room temperature, and then high-temperature aging treatment is carried out, so that the residual Laves/TCP phase is thoroughly dissolved, meanwhile, a high dislocation cellular structure formed in the L-PBF process is reserved, and finally, the excellent performance of cooperative improvement of strength and plasticity is obtained in the high-temperature alloy. The method has simple process, short time and easy industrial popularization.

Inventors

  • Zhu Jiangqi
  • DAI SHENGBIN
  • Yan xingchen
  • GAO SHUOHONG
  • LU BINGWEN
  • WU PENGYUE
  • LI HUAIXUE

Assignees

  • 广东省科学院新材料研究所

Dates

Publication Date
20260505
Application Date
20260210

Claims (9)

  1. 1. The laser powder bed melting additive nickel-based superalloy plastic-strengthening synergistic lifting heat treatment process is characterized by comprising the following steps of: placing an oxide dispersion strengthening nickel-based superalloy test piece prepared by melting a laser powder bed into a protective atmosphere or a vacuum furnace; Heating the oxide dispersion strengthening nickel-based superalloy test piece prepared by melting the laser powder bed to a temperature T 1 in a protective atmosphere or vacuum for a time T 1 to obtain a heated test piece; step three, after heating, taking out the heated test piece and cooling the test piece to room temperature through air; And fourthly, aging the test piece cooled by the air to the room temperature, namely heating the test piece cooled by the air to the room temperature to the temperature T 2 for the time T 2 , and cooling to the room temperature to precipitate a strengthening phase and obtain the final mechanical property.
  2. 2. The laser powder bed melting additive nickel-based superalloy strengthening and plastic cooperative lifting heat treatment process according to claim 1, wherein the oxide dispersion strengthening nickel-based superalloy test piece in the first step is a test piece with removed support, powder removal and uniformity in all directions.
  3. 3. The laser powder bed melting additive nickel-based superalloy plastic strengthening synergistic lifting heat treatment process of claim 1 is characterized in that the average cell diameter of dislocation cell structures formed by printing oxide dispersion strengthening nickel-based superalloy test pieces prepared by melting a laser powder bed in the first step is 1-3 mu m, and the retention rate of the structures is not less than 70% after the second step.
  4. 4. The laser powder bed melting additive nickel-based superalloy strengthening plastic synergistic lifting heat treatment process is characterized in that the chemical components of an oxide dispersion strengthening nickel-based superalloy test piece prepared by laser powder bed melting in the step one are as follows in mass percent: Ni, the balance; Cr:18.0~24.0%; Co:3.0~8.0%; W:2.0~5.0%; Mo:1.5~4.0%; Ti:1.0~2.0%; Al:0.8~2.0%; Y 2 O 3 :0.4~1.2%; Hf:0.1~0.5%; Nb 4 C 3 T x :0.1-0.5%; the content of other alloy elements is C, B, zr, ta, nb per item not more than 0.3%.
  5. 5. The laser powder bed melting additive nickel-based superalloy strengthening plastic synergistic lifting heat treatment process according to claim 4, wherein the preparation method of Nb 4 C 3 T x is characterized by comprising the following steps: 1) Weighing Nb powder, al powder and graphite according to an atomic ratio of 4:1.5:2.7, mixing, and performing ball milling treatment to obtain dry mixed powder; 2) Placing the dry mixed powder into a high-temperature tube furnace, performing pressureless sintering under the protection of argon, preserving heat for 4-8 hours at 1450-1600 ℃, and cooling to room temperature along with the furnace to obtain a solid phase material Nb 4 AlC 3 ; 3) Adding a solid phase material Nb 4 AlC 3 into an HF solution with the mass fraction of 45-60%, magnetically stirring at room temperature for reaction for 120-145 hours, and centrifugally separating after the reaction is finished to obtain an Nb 4 C 3 T x initial product; 4) Dispersing the Nb 4 C 3 T x initial product in dimethyl sulfoxide solution, controlling the concentration of the system to be 28-32mg/mL, and magnetically stirring at room temperature for 10-12 hours; 5) And (3) carrying out centrifugal separation after stirring, taking the aqueous solution of the water, carrying out suction filtration, and drying a filter cake to obtain the purified Nb 4 C 3 T x .
  6. 6. The laser powder bed melting additive nickel-based superalloy plastic-strengthening collaborative lifting heat treatment process according to claim 1, wherein the protective atmosphere in the first step is argon or nitrogen, and the vacuum degree of the vacuum furnace is below 10 -4 Pa.
  7. 7. The laser powder bed melting additive nickel-based superalloy plastic-strengthening collaborative lifting heat treatment process according to claim 1, wherein in the second step, the temperature T 1 is 1200-1250 ℃, the heating rate is 10-30 ℃ per minute, and the time T 1 is 5-30 minutes.
  8. 8. The laser powder bed melting additive nickel-based superalloy plastic-strengthening collaborative lifting heat treatment process according to claim 1, wherein air cooling in the third step is natural convection cooling or is assisted by slightly forced air circulation.
  9. 9. The laser powder bed melting additive nickel-based superalloy plastic-strengthening collaborative lifting heat treatment process according to claim 1, wherein in the fourth step, the temperature T 2 is 700-850 ℃, and the time T 2 is 2-8 hours.

Description

Laser powder bed melting material-increasing nickel-based superalloy strong plastic synergistic lifting heat treatment process Technical Field The invention relates to the technical field of metal post heat treatment, in particular to a laser powder bed melting material-increasing nickel-based superalloy plastic strengthening collaborative lifting heat treatment process. Background Nickel-based superalloy is widely used in the key fields of aeroengines, gas turbines, high-temperature structural members and the like due to its excellent high-temperature strength, creep resistance, oxidation resistance and corrosion resistance. For a long time, alloy design has been dependent mainly on fine control of gamma/gamma' phase structure, solid solution strengthening, precipitation strengthening, and thermo-oxidative coating techniques. For example, as early as 1970 there was a patent for adding aluminum, chromium, yttrium elements to nickel-based alloys to form stable protective oxide layers, nickel-chromium-aluminum-yttrium (Ni-Cr-Al-Y) systems significantly improved the oxidation-erosion resistance of the alloys by forming dense Al 2O3 protective films. With the development of materials and manufacturing techniques, oxide Dispersion Strengthening (ODS) nickel-based superalloys are increasingly becoming an effective way to increase high temperature creep life and high temperature strength. In this technical route, creep resistance under high temperature load can be significantly improved by dispersing high temperature resistant, thermally stable nano-oxides (e.g., Y 2O3、YHfO3, etc.) into nickel-based matrices. Early studies showed that ODS nickel-base alloys such as "TMO-2" have achieved a fracture life exceeding 7000 hours at 1050 ℃ per 16kgf/mm 2 by mechanical alloying, extrusion and solution treatment. However, the conventional manufacturing process of ODS alloy is mostly based on powder metallurgy, hot isostatic pressing or extrusion process, and is limited in terms of capability of forming complex parts, material utilization and geometric complexity. In recent years, additive Manufacturing (AM) technology, particularly laser powder bed fusion (L-PBF, laserPowderBedFusion) processes, has shown great potential in the manufacture of complex structural parts. By laying powder layer by layer, laser melting and quick cooling, the high material utilization rate, the light-weight structure and the high-complexity geometric characteristics can be realized. For example, WO2021/234368A1 discloses a powder bed melt additive manufacturing method for nickel-base superalloys, which indicates that the technique is applicable to nickel-base alloys such as CM247LC. In the academic world, a study on a new gamma prime strengthened nickel-base alloy MAD542 in an L-PBF process shows that a component with the crack rate lower than 0.06% is successfully obtained through optimizing printing and post-treatment, and the study emphasizes the importance of the influence of the L-PBF process on alloy tissues (such as gamma prime precipitation, recrystallization structure and twin crystal structure). Nevertheless, the combination of L-PBF technology with ODS nickel-based superalloys still faces many challenges. First, the L-PBF process has extremely high local cooling rate, severe thermal cycle and high thermal gradient, and is easy to form unbalanced structure, enrich elements, indissolvable precipitated phases (such as Laves phase and TCP phase) and high-density dislocation and residual stress in the alloy. For example, IN studies of AM production of IN718 alloy, the authors indicated that non-optimized heat treatment could not completely eliminate Laves phase or delta phase and that dislocation cellular structure typical of L-PBF fabrication could lead to significant plastic degradation if recovered or recrystallized. In another study of L-PBF fabrication HastelloyX alloys, the presence of microscopic defects such as thermal cracking risk, dendrite/columnar crystal structure, and fine carbide rich zones was also pointed out. Secondly, in ODS nickel-based alloys, the dispersion strengthening mechanism of nano-oxides depends on stable matrix fine structure and high dislocation density, cellular sub-crystalline structure or precipitation strengthening phase structure. If the heat treatment is improper, coarsening of oxide particles, non-uniformity of precipitated phases, recovery of dislocation structure or recrystallization may be caused, thereby weakening the strengthening mechanism. In addition, the residual of hard and brittle precipitated phases such as Laves seriously degrades the plastic properties and becomes a crack initiation source. Disclosure of Invention Based on the problems of the background technology, the invention provides a laser powder bed melting additive nickel-based superalloy plastic strengthening collaborative lifting heat treatment process. Through ultrahigh temperature and extremely short time treatment and an air