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CN-122007713-A - Nickel-based brazing filler metal for single-crystal superalloy DD10 brazing, preparation method thereof and brazing method

CN122007713ACN 122007713 ACN122007713 ACN 122007713ACN-122007713-A

Abstract

The invention discloses a nickel-based brazing filler metal for single-crystal high-temperature alloy DD10 brazing, a preparation method and a brazing method thereof, and belongs to the field of nickel-based high-temperature alloy brazing, wherein the total atomic percentage of Al, ti, ta, nb in the nickel-based brazing filler metal is 12 at% -16 at%, and the total atomic percentage of B and Si is 1.5 at% -2.0 at%, compared with the traditional nickel-based brazing filler metal, the nickel-based brazing filler metal has the advantages that the volume fraction and the size of gamma' -phase in a brazing seam are regulated and controlled, so that the high-temperature strength and the toughness of a single-crystal high-temperature alloy DD10 brazing joint are synergistically improved, the volume fraction of brittle phases is reduced to below 5%, the problem of high-temperature embrittlement is solved, and the creep fracture time of the single-crystal high-temperature alloy DD10 brazing joint reaches 350-400h at 1000 ℃ per 100 MPa.

Inventors

  • SHAO YUXIN
  • GUO WEI

Assignees

  • 东北大学

Dates

Publication Date
20260512
Application Date
20260409

Claims (10)

  1. 1. The nickel-based brazing filler metal for single-crystal superalloy DD10 brazing is characterized by comprising ：Co 8.5at.%-9.5at.%,Cr 7.5at.%-8.5at.%,Mo 2.2at.%-2.8at.%,W 1.2at.%-1.8at.%,Al 4.5at.%-5.5at.%,Ti 2.5at.%-3.5at.%,Ta 3.5at.%-4.5at.%,Nb 1.5at.%-2.5at.%,B 0.9at.%-1.1at.%,Si 0.6at.%-0.9at.%,La 0.15at.%-0.25at.%,Nd 0.12at.%-0.18at.%, by atomic percent of the following elements and the balance of Ni; wherein, the total atomic percent of Al, ti, ta, nb is 12at.% to 16at.%, and the total atomic percent of B and Si is 1.5at.% to 2.0at.%.
  2. 2. The preparation method of the nickel-based brazing filler metal for single-crystal superalloy DD10 brazing is characterized by comprising the following steps of: Firstly, weighing Ni, co, cr, al, ta, ti, mo, nb, W, B, si, la, nd parts of powder of the nickel-based brazing filler metal according to the atomic percentage of the nickel-based brazing filler metal in claim 1, cleaning and drying, and mixing by adopting a double planetary mixer to obtain mixed powder; Secondly, preparing melt from the mixed powder by adopting an induction smelting method, and preparing foil-shaped brazing filler metal by adopting a double-roller casting-rolling method; and thirdly, carrying out stress relief annealing on the foil-shaped brazing filler metal, and carrying out ultrasonic cleaning, deionized flushing and drying on the foil-shaped brazing filler metal to obtain the nickel-based brazing filler metal.
  3. 3. The method for preparing the nickel-based brazing filler metal for DD10 brazing of the single crystal superalloy according to claim 2, wherein in the step one, the cleaning process adopts absolute ethyl alcohol for ultrasonic cleaning for 20min, and in the drying process, 40min is dried in a vacuum drying oven with the temperature of 85 ℃.
  4. 4. The method for preparing nickel-based brazing filler metal for single-crystal superalloy DD10 brazing according to claim 2, wherein in the step two, in the process of preparing the foil-shaped brazing filler metal by the twin-roll casting and rolling method, a bottom pouring type tundish is adopted to guide the melt into a twin-roll mill, the gap between rolls of the twin-roll mill is 0.045 mm-0.055 mm, the roll speed is 1900 rpm-2100 rpm, and the foil-shaped brazing filler metal is obtained by rolling.
  5. 5. The method for producing a nickel-based brazing filler metal for DD10 brazing of a single crystal superalloy as in claim 4 wherein the thickness of the foil-like brazing filler metal is 45 μm to 55. Mu.m.
  6. 6. The method for preparing a nickel-based brazing filler metal for DD10 brazing of a single crystal superalloy according to claim 2, wherein the temperature of the stress relief annealing in the third step is 650 ℃, the annealing time is 80min, and the cooling speed is 25 ℃ per hour to 30 ℃ per hour after cooling with a furnace.
  7. 7. A brazing method of single-crystal high-temperature alloy DD10 is characterized in that nickel-based brazing filler metal in claim 1 is placed between an upper layer of pretreated single-crystal high-temperature alloy DD10 parent metal and a lower layer of pretreated single-crystal high-temperature alloy DD10 parent metal, and then the single-crystal high-temperature alloy DD10 brazing joint is obtained by brazing in a vacuum brazing furnace.
  8. 8. The method of brazing a single crystal superalloy DD10 according to claim 7, wherein the brazing is performed by a gradient heating and pressurizing method including a first stage of heating from room temperature to 350 ℃ at a heating rate of 8 ℃ per minute, applying a pressure of 0.5MPa and maintaining the temperature at 350 ℃ for 15 minutes, a second stage of heating from 350 ℃ to 750 ℃ at a heating rate of 8 ℃ per minute, applying a pressure of 0.8MPa and maintaining the temperature at 750 ℃ for 15 minutes, a third stage of heating from 750 ℃ to 1050 ℃ at a heating rate of 8 ℃ per minute, applying a pressure of 1.0MPa and maintaining the temperature at 1050 ℃ for 15 minutes, a fourth stage of heating from 1050 ℃ to 1220 ℃ at a heating rate of 5 ℃ per minute, applying a pressure of 1.2MPa and maintaining the temperature at 1250 ℃ and cooling the temperature with the furnace to room temperature, and a vacuum degree of the vacuum brazing furnace 。
  9. 9. The brazing method of single crystal superalloy DD10 according to claim 7, wherein the volume fraction of gamma prime phase in the brazing joint of the single crystal superalloy DD10 is 40% -45%, and the gamma prime phase size is 0.2 μm-0.5 μm.
  10. 10. The brazing method of the single crystal superalloy DD10 according to claim 7, wherein the single crystal superalloy DD10 brazing joint has a creep rupture time of 350-400 h at a temperature of 1000 ℃ and a pressure of 100MPa and a shear strength of 480-500 MPa at 1000 ℃.

Description

Nickel-based brazing filler metal for single-crystal superalloy DD10 brazing, preparation method thereof and brazing method Technical Field The invention relates to the field of nickel-based superalloy brazing, in particular to a nickel-based brazing filler metal for single-crystal superalloy DD10 brazing, a preparation method thereof and a brazing method thereof. Background The new generation aero-engine iterates to a high thrust-weight ratio (more than or equal to 12), the service temperature of the high-pressure turbine blade breaks through 1100 ℃, complex thermal cycle and alternating load are required to be born, and strict requirements are provided for the high-temperature mechanical property, creep resistance stability and corrosion resistance durability of the connecting joint. The single-crystal superalloy DD10 eliminates the weakening effect of the grain boundary by virtue of a single-crystal structure, and has the lasting strength of more than 350MPa at 1000 ℃ and becomes a core material of the high-pressure turbine blade. In the connection process of the single-crystal superalloy DD10, laser welding/electron beam welding is easy to cause recrystallization of a single-crystal matrix due to concentrated heat input, high-temperature performance is suddenly reduced, diffusion welding is required to be carried out for 8-12 h at 1250 ℃ under 15MPa, production efficiency is low, parent metal element segregation is easy to cause, and friction welding is only applicable to simple components such as shafts and cannot be matched with complex structures such as blade tenons, air film holes and the like. The brazing is low in heat input (the peak temperature is less than or equal to 1250 ℃), single crystal recrystallization can be avoided, and the filling rate of the molten brazing filler metal to a complex gap reaches more than 99%, so that the brazing filler metal is a preferable technical path for connecting single crystal superalloy DD 10. The existing nickel-based brazing filler metals (such as BNi-2 and BNi-5) have three main core defects that ① interface bonding strength is insufficient (room temperature shearing strength is less than or equal to 700 MPa), massive boride (such as Ni 3 B) and silicide (such as Ni 2 Si) are easy to separate out at ② high temperature due to poor matching property of the brazing filler metal and gamma' -shaped of single crystal superalloy DD10, brittle phase volume fraction at 1000 ℃ can reach 15% -20%, joint creep rupture time is less than or equal to 100h, and ③ has limited high temperature oxidation resistance (oxidation weight gain is more than or equal to 8mg/cm 2 after 1000 ℃ cyclic oxidation for 100 h). Therefore, research and development of the nickel-based brazing filler metal with the precise component regulation and control type for the DD10 becomes a key for breaking through the high-temperature connection bottleneck of the aeroengine. Disclosure of Invention Aiming at the defects in the background art, the invention improves the structure of the single-crystal superalloy DD10 braze welding joint by brand new design of the brazing filler metal components, improves the mechanical property of the joint, and provides technical support for high-strength and high-toughness connection of the single-crystal superalloy DD 10. In order to achieve the above object, according to a first aspect of the present invention, there is provided a nickel-based brazing filler metal for DD10 brazing of a single crystal superalloy, the nickel-based brazing filler metal comprising ：Co 8.5at.%-9.5at.%,Cr 7.5at.%-8.5at.%,Mo 2.2at.%-2.8at.%,W 1.2at.%-1.8at.%,Al 4.5at.%-5.5at.%,Ti 2.5at.%-3.5at.%,Ta 3.5at.%-4.5at.%,Nb 1.5at.%-2.5at.%,B 0.9at.%-1.1at.%,Si 0.6at.%-0.9at.%,La 0.15at.%-0.25at.%,Nd 0.12at.%-0.18at.%, by atomic percent of the following elements, the balance being Ni; wherein, the total atomic percent of Al, ti, ta, nb is 12at.% to 16at.%, and the total atomic percent of B and Si is 1.5at.% to 2.0at.%. The invention provides a preparation method of a nickel-based brazing filler metal for single-crystal superalloy DD10 brazing, which comprises the following steps: firstly, weighing Ni, co, cr, al, ta, ti, mo, nb, W, B, si, la, nd powder according to the atomic percentage of the nickel-based brazing filler metal, cleaning and drying, and mixing by adopting a double planetary mixer to obtain mixed powder; Secondly, preparing melt from the mixed powder by adopting an induction smelting method, and preparing foil-shaped brazing filler metal by adopting a double-roller casting-rolling method; and thirdly, carrying out stress relief annealing on the foil-shaped brazing filler metal, and carrying out ultrasonic cleaning, deionized flushing and drying on the foil-shaped brazing filler metal to obtain the nickel-based brazing filler metal. Preferably, in the first step, the cleaning process adopts absolute ethyl alcohol for ultrasonic cleaning for 20min, and in the drying process, 40min