High-second-phase-content powder high-temperature alloy strengthening and toughening method based on multi-scale collaborative mechanism

Abstract

The invention discloses a high-second-phase-content powder high-temperature alloy strengthening and toughening method based on a multi-scale cooperative mechanism. The method comprises a blank pretreatment stage, a heating stage, a deformation stage, a rapid cooling stage and a secondary cooling stage. In the heating stage, the blank is heated to the temperature below the second-phase complete dissolution temperature, so that the blank is uniformly heated, and second-phase particles enter a heat balance state; in the deformation stage, the blank is deformed, crystal grains are refined, second-phase particles are redistributed and further redissolved, and meanwhile a large number of deformation twin crystals are obtained; and in the rapid cooling stage, the deformed blank is rapidly cooled to the temperature below the second phase complete precipitation temperature, the second phase is rapidly and fully precipitated, then long-time heat preservation is conducted, grains which are not completely recrystallized are fully recrystallized, uniform fine grains and annealing twin crystals are obtained, meanwhile, second phase particles are fully precipitated, and the stability of the second phase particles is improved. According to the method, the blank is strong and tough and can meet the service requirements of high-performance aero-engine hot end components.

Description

Technical Field

[0001] The present invention belongs to the technical field of material strengthening, and specifically relates to a method for strengthening and toughening a high-second-phase-content powder high-temperature alloy based on a multi-scale synergistic mechanism. Background Art

[0002] Powdered superalloys are a key structural material capable of maintaining excellent mechanical properties under long-term service conditions of 650°C to 850°C. They are widely used in high-temperature environments, such as high-performance aircraft engines, and are currently the preferred material for manufacturing turbine disks for high-thrust-to-weight ratio aircraft engines. As the thrust-to-weight ratio of aircraft engines continues to increase, powdered superalloys must simultaneously meet higher requirements for strength, toughness, and high-temperature stability.

[0003] Powder-coated superalloys with high second-phase content exhibit excellent strength and fatigue resistance due to their significant precipitation strengthening effects. However, in these alloys, after hot isostatic pressing (HIP), large second-phase particles often distribute along grain boundaries. This distribution pattern can lead to premature crack initiation, weakening the toughness of the material. Furthermore, the large second-phase particles have limited resistance to dislocation motion, preventing them from fully realizing their strengthening effect. Furthermore, due to the characteristics of powder metallurgy, these alloys inevitably contain defects such as uneven grain distribution and primary grain boundaries, which further reduce the strength and toughness of the material. Existing strengthening mechanisms, such as grain refinement and second-phase dispersion strengthening, can improve strength, but due to their single strengthening mechanism, they are often accompanied by a decrease in toughness, making it difficult to simultaneously meet the multiple strength and toughness requirements of superalloys under complex service conditions. Furthermore, in conventional high-second-phase-content powder-coated superalloys, the primary precipitation strengthening mechanism is γ′ above 55%, primarily through second-phase precipitation strengthening. Dispersion strengthening is achieved by adjusting the size and distribution of the second phase through solution and aging heat treatment after HIP, but this can lead to a decrease in toughness. For example, Chinese patent application CN117358924A discloses a method for grain boundary engineering of nickel-based alloys based on powder hot isostatic pressing (HIP) technology and its application. This method achieves the technical effect of improving low ΣCSL grain boundaries, such as Σ3 grain boundaries, during HIP by screening powder and strictly setting HIP process conditions. However, this application only explores how to improve low ΣCSL grain boundaries in nickel-based alloys and does not address the relationship between high-order twin boundaries and grain boundary structure and the strength and toughness of superalloys. Chinese patent application CN114657488A discloses a process for increasing twin boundaries in nickel-based powder superalloys. This method increases twin boundaries through high-temperature double-pass compression and high-temperature solutionization, thereby improving the creep and fatigue resistance of nickel-based powder superalloys during high-temperature service. However, the increase in twin boundaries in this application is not significant, and it only improves the creep and fatigue resistance of nickel-based powder superalloys during high-temperature service. Therefore, to meet the service requirements of powder superalloys with high second-phase content, there is an urgent need to develop a technical method that can achieve simultaneous improvements in strength and toughness. Summary of the Invention

[0004] In view of the above-mentioned problems of the prior art, the purpose of the present invention is to propose a strengthening and toughening method based on a multi-scale synergistic mechanism. By introducing multiple strengthening mechanisms into the microstructure of the material, a synergistic effect of strengthening and toughening is achieved within a multi-scale range, which can effectively solve the problem of insufficient toughness of powder high-temperature alloys with high second-phase content. The multi-scale synergistic strengthening and toughening method proposed in the present invention specifically optimizes the size and distribution of the second phase, refines the matrix grain structure, introduces a large number of twin structures to optimize the interface, and reduces defects introduced by the metallurgical process, thereby significantly improving the comprehensive mechanical properties of the material under complex service conditions, providing important technical support for the strengthening and toughening of high-performance powder high-temperature alloys.

[0005] To achieve the aforementioned objectives, the present invention provides a method for strengthening and toughening a high-second-phase-content powder superalloy based on a multi-scale synergistic mechanism. This method has a short process flow and can produce a uniform microstructure with fine grains, a dispersed second phase, and numerous twins, thereby increasing both material strength and toughness.

[0006] The objectives of the present invention are achieved through the following technical solutions.

[0007] The method for strengthening and toughening a high-second-phase-content powder high-temperature alloy based on a multi-scale synergistic mechanism of the present invention includes a billet pretreatment stage, a heating stage, a deformation stage, a rapid cooling stage, and a secondary cooling stage; The powder high-temperature alloy with a high second-phase content is a nickel-based powder high-temperature alloy prepared by a powder metallurgy process, with γ′ as the main precipitation strengthening phase and a molar fraction higher than 55%; The blank pretreatment stage includes processing the hot isostatically pressed blank into a predetermined size, wrapping the blank with a heat-insulating material, applying a lubricant between the heat-insulating material and the blank, and fixing the heat-insulating material to the blank; The heating stage includes heating the blank from room temperature to a temperature below the temperature at which the second phase completely dissolves, and maintaining the temperature, so that the blank is heated uniformly and the second phase particles enter a thermal equilibrium state; The deformation stage includes placing the fully homogenized billet under a press and deforming it at least once at a predetermined strain rate and deformation amount, so that the grains in the billet are refined, the second phase particles are redistributed and further dissolved, and a large number of deformation twins are obtained; The rapid cooling stage includes rapidly cooling the deformed billet to a temperature below the second phase precipitation transition point, so that the second phase particles in the billet are rapidly precipitated to obtain a dispersed second phase; and fully temperature-homogenizing the rapidly cooled billet so that the grains that have not yet been fully recrystallized are fully recrystallized to obtain uniform and fine grains, while also allowing the second phase particles to fully precipitate and improve their stability. The secondary cooling stage includes cooling the temperature-equilibrated billet to room temperature.

[0008] In some possible implementations of the present invention, the temperature below the complete dissolution temperature of the second phase is between 1120° C. and 1170° C.

[0009] In some possible implementations of the present invention, the insulation time of the heating stage is more than 20 minutes.

[0010] In some possible implementations of the present invention, the heating includes multi-stage heating. The inventors have found that as the size of the blank (workpiece) increases, segmenting the heating helps to evenly heat the blank and avoid negative defects such as cracking of the blank.

[0011] In some possible implementations of the present invention, the predetermined deformation amount is between 40% and 50%, and the predetermined strain rate is between 10 -2 -10 1 The inventors found that deformation rates below 40% do not accumulate sufficient deformation energy storage within the material, hindering grain refinement. Furthermore, due to the thermoplasticity of the alloy, deformation rates above 50% can cause deformation cracks in the alloy. Too low a strain rate can lead to rapid growth of recrystallized grains, significantly reducing the grain refinement strengthening effect, while too high a strain rate can dramatically increase the material's deformation resistance, potentially damaging the mold.

[0012] In some possible implementations of the present invention, the deformation includes multiple, different-directional extrusion deformations. The inventors have discovered that the number and direction of deformations can be adjusted according to the size and shape of the blank to achieve the desired effect during the process.

[0013] In some possible implementations of the present invention, the temperature below the second phase precipitation transition point is between 900-1000°C.

[0014] In some possible implementations of the present invention, the temperature equalization time in the rapid cooling stage is more than 10 hours.

[0015] In some possible implementations of the present invention, the cooling means in the secondary cooling stage includes one or more of air cooling, oil quenching, and gas quenching.

[0016] The toughening method of the present invention can be applied to the toughening treatment of high-temperature service parts such as aircraft engine disks and blades.

[0017] The technical solution of the present invention is based on the following findings of the inventors. During the heating and holding stage, the powder high-temperature alloy billet is uniformly heated, and the second-phase γ′ particles therein enter a thermal equilibrium state, which is conducive to the subsequent redistribution and further dissolution of the second-phase particles in the deformation stage, while obtaining a large number of deformation twins, and at the same time helping to improve the stability of the organizational evolution. During the deformation stage, small deformations can partially refine the grains to produce some fine grains, while providing a certain driving force for the recrystallization of the alloy; small deformations at high temperatures can also introduce a large number of deformation twins into nickel-based high-temperature alloys that are difficult to obtain by traditional methods; a large number of dislocations appear in the billet structure during deformation, which provide channels for rapid diffusion of the second-phase particles, promote the redistribution and further dissolution of the second-phase particles, and help to obtain a dispersed second phase in the subsequent rapid cooling stage. In the rapid cooling stage, the blank is quickly cooled to a limited temperature, so that the second-phase particles that have been redistributed and further dissolved can be quickly precipitated to obtain a dispersed second phase. These dispersed second phases pin the grain boundaries to prevent the fine grains obtained in the deformation stage from growing in subsequent processes such as temperature equalization. In the temperature equalization process, the grains that have not yet been fully recrystallized are fully recrystallized to obtain uniform fine grains and form a large number of annealing twins. At the same time, the second-phase particles are fully precipitated and their stability is improved, which is equivalent to a solution treatment. This can reduce or even omit the solution step in the traditional heat treatment process.

[0018] The beneficial effects of the present invention are:

[0019] 1. The method of the present invention combines a limited heating temperature, a small deformation process on the fully heated billet, and a temperature uniformization of the billet after rapid cooling to a limited temperature, thereby achieving fine grain strengthening, twin strengthening and second-phase dispersion strengthening of the nickel-based high-temperature alloy in a single heating process. The synergy of the three greatly improves the strength of this type of alloy while improving its toughness, thereby meeting the service requirements of high-performance aircraft engine turbine disks.

[0020] 2. Compared with other plastic deformation-solution-aging processes, the method of the present invention can reduce at least two heatings during solution and aging (for multi-stage aging, multiple heatings are required, and single-stage aging requires one heating), shortening the process flow and saving energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic flow chart of the method according to the present invention;

[0022] Figure 2 : These are microstructure images of a blank prepared according to an embodiment of the method of the present invention, wherein (a) is a grain boundary image (including twin boundaries), with a grain size of approximately 11-12 levels and twin boundaries accounting for approximately 80%, and (b) is a second phase microstructure morphology with an average grain size of 153 nm.

[0023] Figure 3 It is a flow chart of the traditional method;

[0024] Figure 4 The microstructure images of the blank prepared by the traditional method are shown in Figure 1. (a) shows the grain boundary image (including twin boundaries), with a grain size of approximately 6-7 and a twin boundary ratio of approximately 30%. (b) shows the second phase microstructure morphology with an average grain size of 1.37 μm.

[0025] Figure 5 is a comparison chart of the mechanical properties of the blank prepared according to an embodiment of the method of the present invention and the blank prepared according to the comparative example, including the yield strength σ 0.2 , tensile strength σ b and elongation after break δ. DETAILED DESCRIPTION

[0026] The following is a clear and complete description of the technical solutions in the embodiments of the present invention, in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them, and do not constitute a limitation of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] The technical solution of the present invention is not limited to the specific implementation methods listed below, but also includes any combination of the specific implementation methods.

[0028] Example 1:

[0029] See also Figure 1 In this embodiment, the strengthening and toughening method of high-second-phase-content powder superalloy based on the multi-scale synergistic mechanism includes the following stages:

[0030] (1) Billet pretreatment stage: cylindrical billet (size The outer surface of the blank (100 mm × 80 mm) is machined, and the upper and lower end faces are chamfered. Then, forging lubricant is evenly applied to the outside of the blank. After it is fully dried, the blank is wrapped with a high-temperature resistant fiber blanket of appropriate size according to the size of the blank and fixed with thin iron wire.

[0031] (2) Heating and holding stage: The heating process curve is set into two stages based on the geometric dimensions of the billet. The first stage has a heating rate of 20°C / min, a heating temperature of 700-800°C, and a holding time of 30 minutes. The second stage has a heating rate of 10°C / min, a heating temperature of 1120-1170°C (i.e., a temperature below the temperature at which γ′ completely re-dissolves), and a holding time of 60 minutes. The billet is placed in a heating furnace and heated according to the set heating process curve.

[0032] (3) Deformation stage: According to the size of the blank and the final size requirements, the press operation curve is compiled, and the deformation stroke of the press is set to 13 mm, the deformation rate is 0.1 / s, the number of deformations is 2 times, and the deformation direction is the same. The fully uniform temperature blank is taken out of the heating furnace, quickly transferred to the upper and lower molds of the press, and high-temperature lubricant is sprinkled on the surface of the lower mold and the upper surface of the blank. The blank is deformed according to the compiled press operation curve. The temperature in the deformation stage is maintained at 1120-1170℃. The transfer time in this stage is short, the deformation is fast, and the material is coated with insulation material, see the high-temperature resistant fiber blanket in step 1, so no additional heating is required.

[0033] (4) Rapid cooling stage: After deformation, the surface temperature of the blank is measured with an infrared thermometer, and the blank is subjected to forced convection to quickly cool down to 900-1000°C. The cooled blank is then quickly transferred to a preheated heating furnace for full temperature equalization, and the temperature equalization time is 20 hours.

[0034] (5) Secondary cooling stage: After the temperature is equalized, the blank is taken out of the heating furnace and completely cooled to room temperature in the air.

[0035] Example 2:

[0036] In this embodiment, the method for strengthening and toughening a high-second-phase-content powder superalloy based on a multi-scale synergistic mechanism includes the following stages:

[0037] (1) Billet pretreatment stage: cylindrical billet (size The outer surface of the blank (50 mm × 30 mm) is machined, and the upper and lower end faces are chamfered. Then, forging lubricant is evenly applied to the outside of the blank. After it is fully dried, the blank is wrapped with a high-temperature resistant fiber blanket of appropriate size according to the size of the blank and fixed with thin iron wire.

[0038] (2) Heating and holding stage: The heating process curve is set as one stage based on the geometric dimensions of the billet, with a heating rate of 10°C / min, a heating temperature of 1120-1170°C, and a holding time of 20 minutes. The billet is placed in a heating furnace and heated according to the set heating process curve.

[0039] (3) Deformation stage: Based on the size of the blank and the final size requirements, a press operation curve is compiled. The press deformation stroke is set to 15 mm, the deformation rate is 1 / s, and the unidirectional deformation is 1 time. The temperature during the deformation stage is maintained at 1120-1170°C. The fully heated blank is removed from the heating furnace and quickly transferred between the upper and lower molds of the press. High-temperature lubricant is applied to the lower mold surface and the upper surface of the blank. The blank is deformed according to the compiled press operation curve.

[0040] (4) Rapid cooling stage: After deformation, the surface temperature of the blank is measured with an infrared thermometer, and the blank is subjected to forced convection to quickly cool down to 900-1000°C. The cooled blank is then quickly transferred to a preheated heating furnace for full temperature equalization, and the temperature equalization time is 10 hours.

[0041] (5) Secondary cooling stage: After the temperature is equalized, the billet is taken out of the heating furnace and completely cooled to room temperature by oil quenching.

[0042] Example 3: In this embodiment, the method for strengthening and toughening a high-second-phase-content powder superalloy based on a multi-scale synergistic mechanism includes the following stages:

[0043] (1) Billet pretreatment stage: cylindrical billet (size The outer surface of the blank (200 mm × 100 mm) is machined, and the upper and lower end faces are chamfered. Then, forging lubricant is evenly applied to the outside of the blank. After it is fully dried, the blank is wrapped with a high-temperature resistant fiber blanket of appropriate size according to the size of the blank and fixed with thin iron wire.

[0044] (2) Heating and holding stage: The heating process curve is set into two stages based on the material and geometric dimensions of the billet. The first stage has a heating rate of 15°C / min, a heating temperature of 700-800°C, and a holding time of 60 minutes. The second stage has a heating rate of 8°C / min, a heating temperature of 1120-1170°C, and a holding time of 60 minutes. The billet is placed in a heating furnace and heated according to the set heating process curve.

[0045] (3) Deformation stage: According to the size of the blank and the final size requirements, the press operation curve is compiled, and the deformation stroke of the press is set to 40 mm and the deformation rate is set to 10 -2 / second, the number of deformations is two, and the deformation directions are perpendicular. The temperature during the deformation phase is maintained at 1120-1170°C. The fully heated billet is removed from the heating furnace and quickly transferred between the upper and lower dies of the press. High-temperature lubricant is applied to the lower die surface and the upper surface of the billet. The billet is deformed according to the compiled press operation curve.

[0046] (4) Rapid cooling stage: After deformation, the surface temperature of the blank is measured with an infrared thermometer, and the blank is subjected to forced convection to quickly cool down to 900-1000°C. The cooled blank is then quickly transferred to a preheated heating furnace for full temperature equalization, and the temperature equalization time is 25 hours.

[0047] (5) Secondary cooling stage: After the temperature is equalized, the billet is taken out of the heating furnace and completely cooled to room temperature by oil quenching.

[0048] Comparative Example:

[0049] See also Figure 3 In this comparative example, a conventional strengthening and toughening method of a high second phase content powder superalloy is shown, comprising the following stages:

[0050] (1) Solution heating and holding stage: Using a billet of the same size and material as in Example 1, the solution heating process curve was set to two sections. The first section had a heating rate of 20°C / min, a heating temperature of 700-800°C, and a holding time of 30 minutes. The second section had a heating rate of 10°C / min, a heating temperature of 1170-1200°C (i.e., a temperature above the temperature at which γ′ completely dissolves back), and a holding time of 8 hours. The billet was placed in a heating furnace and heated according to the set solution heating process curve to ensure that the second phase particles were completely dissolved and the grains grew to a steady state.

[0051] (2) Solution furnace cooling stage: After the insulation is completed, the heating device of the heating furnace is turned off and the furnace is cooled to 1150-1170℃ to precipitate some second phase particles.

[0052] (3) Solution air cooling stage: After the furnace cooling is completed, the furnace is immediately taken out and air cooled to room temperature to ensure that the second phase particles are completely precipitated.

[0053] (4) Aging heating stage: Based on the billet size, an aging heating curve is prepared, with the heating temperature set at 800-900°C, the heating rate set at 15°C / min, and the holding time set at 30 hours. The billet is placed in a heating furnace and heated according to the set aging heating process curve to ensure that the second phase particles are completely precipitated and enter a stable state.

[0054] (5) Aging cooling stage: After the aging heating stage is completed, take it out and air cool it to room temperature immediately.

[0055] The blanks obtained by the toughening method according to Example 1 of the present invention and the comparative example were sampled and microstructure images of the blanks were prepared respectively, as shown in FIG. Figure 2 and Figure 4 As shown. Figure 2 (a) (i.e. Figure 2Left side), the Σ3 twin boundary is shown in red, and the Σ9, Σ27a and Σ27b high-order twin boundaries are shown in purple and dark and light green respectively. Through image processing, it can be seen that the grain size is about 11-12 levels, and the twin boundaries account for about 80%. Figure 2 (b) Figure 2 The right side picture shows the microstructure of the second phase, with an average particle size of 153nm. Figure 4 (a) (i.e. Figure 4 (left figure), the Σ3 twin boundary is shown in red, and the Σ9, Σ27a and Σ27b high-order twin boundaries are shown in purple and dark and light green respectively. Through image processing, it can be seen that the grain size is about 6-7 levels, and the twin boundary accounts for about 30%, which is much lower than the 80% of Example 1 of the present invention. Figure 3 (b) Figure 2 The right side of the figure shows the microstructure of the second phase, with an average particle size of 1.37 μm, which is much larger than the 153 nm of Example 1 of the present invention. Figure 2 and Figure 4 , indicating that the billet prepared by the toughening method of the present invention has a smaller crystal grain size and a large number of twins, which can achieve fine grain strengthening and twin strengthening. At the same time, it can be seen that Figure 2 The size ratio of the second phase precipitated on the grain boundary Figure 4 The smaller the particle size, the more obvious the diffusion enhancement effect.

[0056] The blanks obtained by the toughening method according to Example 1 of the present invention and the comparative example were sampled and tested for yield strength σ 0.2 , tensile strength σ b The mechanical properties test of the elongation after fracture δ obtained Figure 5 The mechanical properties comparison chart of the blank is shown in the figure. Figure 5 It can be seen that the strength and toughness of the blank treated according to Example 1 of the present invention are significantly improved compared to the blank treated by the traditional method.

[0057] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0058] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for strengthening and toughening a high-second-phase-content powder superalloy based on a multi-scale synergistic mechanism, characterized in that: It includes blank pretreatment stage, heating stage, deformation stage, rapid cooling stage and secondary cooling stage; The powder high-temperature alloy with a high second-phase content is a nickel-based powder high-temperature alloy prepared by a powder metallurgy process, with γ′ as the main precipitation strengthening phase and a molar fraction higher than 55%; The blank pretreatment stage includes processing the hot isostatically pressed blank into a predetermined size, wrapping the blank with a heat-insulating material, applying a lubricant between the heat-insulating material and the blank, and fixing the heat-insulating material to the blank; The heating stage includes heating the blank from room temperature to a temperature below the temperature at which the second phase completely dissolves, and maintaining the temperature, so that the blank is heated uniformly and the second phase particles enter a thermal equilibrium state; The deformation stage includes placing the fully homogenized billet under a press and deforming it at least once at a predetermined strain rate and deformation amount, so that the grains in the billet are refined, the second phase particles are redistributed and further dissolved, and deformation twins are obtained; The rapid cooling stage includes rapidly cooling the deformed billet to a temperature below the second phase precipitation transition point, so that the second phase particles in the billet are rapidly precipitated to obtain a dispersed second phase; and fully temperature-homogenizing the rapidly cooled billet so that the grains that have not yet been fully recrystallized are fully recrystallized to obtain uniform fine grains and annealed twins, while also allowing the second phase particles to fully precipitate and improve their stability. The secondary cooling stage includes cooling the temperature-equilibrated billet to room temperature.

2. The method for strengthening and toughening a high-second-phase-content powder superalloy based on a multi-scale synergistic mechanism according to claim 1, characterized in that: The temperature below the complete dissolution temperature of the second phase is between 1120-1170°C.

3. The method for strengthening and toughening a high-second-phase-content powder superalloy based on a multi-scale synergistic mechanism according to claim 1, characterized in that: The heat preservation time of the heating stage is more than 20 minutes.

4. The method for strengthening and toughening a high-second-phase-content powder superalloy based on a multi-scale synergistic mechanism according to claim 1, characterized in that: The heating includes multi-stage heating.

5. The method for strengthening and toughening a high-second-phase-content powder superalloy based on a multi-scale synergistic mechanism according to claim 1, characterized in that: The predetermined deformation is between 40% and 50%, and the predetermined strain rate is between 10 -2 -10 1 / Second.

6. The method for strengthening and toughening a high-second-phase-content powder superalloy based on a multi-scale synergistic mechanism according to claim 1, characterized in that: The deformation includes multiple extrusion deformations in different directions.

7. The method for strengthening and toughening a high-second-phase-content powder superalloy based on a multi-scale synergistic mechanism according to claim 1, characterized in that: The temperature below the second phase precipitation transition point is between 900-1000°C.

8. The method for strengthening and toughening a high-second-phase-content powder superalloy based on a multi-scale synergistic mechanism according to claim 1, characterized in that: The temperature equalization time of the rapid cooling stage is more than 10 hours.

9. The method for strengthening and toughening a high-second-phase-content powder superalloy based on a multi-scale synergistic mechanism according to claim 1, characterized in that: The cooling means in the secondary cooling stage includes one or more of air cooling, oil quenching, and gas quenching.

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