A high-nb reinforced nickel-based superalloy part with excellent strong plasticity matching, a preparation method and application thereof

Abstract

The application belongs to the technical field of powder metallurgy, and particularly relates to a high-Nb strengthening type nickel-based high-temperature alloy workpiece with excellent plasticity matching, a preparation method and application thereof. The preparation method comprises the following steps: uniformly heat treating a high-Nb strengthening type nickel-based high-temperature alloy master alloy rod; preparing alloy powder by adopting a plasma rotating electrode method, and removing impurities by screening and magnetic separation to obtain high-temperature alloy powder; loading the powder into a stainless steel sheath, degassing, sealing and welding, and then performing room temperature pre-deformation treatment; then, performing composite hot isostatic pressing treatment, which is composed of a high-temperature low-pressure stage and a medium-temperature high-pressure stage; and finally, performing solid solution and two-stage aging heat treatment. The application suppresses Nb-rich powder particles and spherical residual dendrites from the source by master alloy homogenization, combines pre-deformation to introduce dislocation induced strengthening phase uniform nucleation, and eliminates original particle boundaries and retains fine grain structure by composite hot isostatic pressing, so that the strength and toughness matching of the alloy is significantly improved, and the alloy is suitable for manufacturing key components of liquid oxygen rocket engines.

Description

Technical Field

[0001] This invention belongs to the field of powder metallurgy technology, specifically relating to a high-Nb-strength nickel-based superalloy part with excellent strength and plasticity matching, its preparation method and application. Background Technology

[0002] With the aerospace industry's increasingly urgent demand for higher thrust and environmental performance in propulsion systems, my country has introduced high-thrust liquid oxygen-kerosene staged combustion cycle rocket engine technology. This type of engine, based on the high-pressure staged combustion principle, operates in an oxygen-rich extreme environment, placing more stringent requirements on the high-temperature resistance, oxidation resistance, and comprehensive mechanical properties of the supporting high-temperature alloy materials. To address this, China has developed the GH4061 nickel-based high-temperature alloy to enable multi-scenario applications under both cryogenic and high-temperature conditions.

[0003] GH4061 alloy is a copy of the Russian EK61 alloy, with a main composition similar to IN718 alloy. It is a castable and forgeable high-Nb strengthened nickel-based superalloy. The total mass fraction of V, Mo, Nb, and Al in the alloy is 9%, and it is mainly strengthened by precipitation through γ″-Ni3Nb and a small amount of γ′-Ni3(Al, Ti) phases. It has excellent comprehensive properties and can be used for short periods in an oxygen-rich corrosive environment at 750℃. Traditionally, GH4061 alloy is usually produced by a dual process of vacuum induction melting (VIM) and vacuum arc remelting (VAR) for master alloy melting. Then, homogenization treatment is used to eliminate low-melting-point phases and dendrite segregation in the ingot, followed by hot die forging and isothermal forging to obtain the final part. However, this traditional process has the following prominent problems: ① Poor microstructure uniformity: The ingot has poor uniformity in terms of grain size, degree of segregation, and phase distribution. Significant differences and poor microstructure uniformity make it difficult to precisely control subsequent forging processes, resulting in large performance fluctuations between batches of parts; ② Narrow hot working window: As-cast alloys usually have severe dendritic segregation, which promotes the formation of low-melting-point eutectic phases (such as Laves phase), reduces the hot plasticity of the alloy during forging, and easily leads to cracks or even scrap, especially for complex-shaped or large-sized forgings; ③ Low material utilization: The forging process requires multiple heating and deformation passes, and leaves machining allowances, resulting in low material utilization and high production costs.

[0004] The traditional GH4061 alloy suffers from poor microstructure uniformity, a narrow hot working window, and low material utilization, which can be fundamentally solved by powder metallurgy. This process achieves microstructural refinement and macroscopic homogenization of alloying elements through rapid solidification, significantly suppressing long-range element segregation. Simultaneously, its near-net-shape forming capability significantly improves material utilization and provides the alloy with a wider hot working window, offering an ideal technical path for preparing high-performance, difficult-to-deform nickel-based alloys.

[0005] However, the original particle boundary (PPB) problem exists when preparing nickel-based superalloys by powder metallurgy. Unlike ordinary nickel-based alloys, high-Nb alloys (Nb content > 5 wt.%) face the following two unique challenges in the powder metallurgy process: (1) Formation of Nb-rich oxide films: During the rapid solidification process of atomized powder preparation, Nb- and Ti-rich oxide films are easily formed on the powder surface. In the subsequent hot isostatic pressing densification stage, C diffuses to the powder surface and combines with the Nb, Ti, and other strong carbide-forming elements enriched therein. MC-type carbides (such as (Nb, Ti)C) preferentially precipitate at the sintering neck, accompanied by oxide film residues. This causes the PPB to exist in the form of continuous or discontinuous chain-like brittle phases, becoming a weak interface in the alloy. During loading, cracks preferentially initiate and propagate along the PPB, leading to a significant deterioration in the tensile plasticity and impact toughness of the alloy, and a decrease in creep rupture life. (2) Formation of spherical residual dendrites: Even with rapid solidification, compositional segregation may still occur inside the atomized powder, forming Nb-rich spherical residual dendrites. These dendrites will diffuse Nb into the PPB during subsequent HIP and heat treatment, further aggravating the precipitation of brittle phases at the PPB. Therefore, how to effectively control or eliminate PPB while fully leveraging the advantages of powder metallurgy in suppressing segregation is one of the key technical challenges in achieving a good balance between strength and toughness in the GH4061 alloy.

[0006] Furthermore, in order to obtain the GH4061 alloy with excellent strength and toughness matching, it is also necessary to precisely control the morphology and distribution of the γ″ strengthening phase. Specifically, the γ″ phase (Ni3Nb), as the most important precipitation strengthening phase in the GH4061 alloy, directly determines the strength, plasticity and impact toughness matching relationship of the alloy over a wide temperature range due to its precipitation location, size, distribution uniformity and coherent strain state with the matrix.

[0007] In view of this, the present invention is hereby proposed. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and propose a high-Nb-strength nickel-based superalloy part with excellent strength-ductility matching, its preparation method and application. This method, through a whole-process coordinated control approach of "homogenization pretreatment - powder preparation - room temperature pre-deformation - composite hot isostatic pressing - heat treatment", aims to overcome the problem of poor strength-toughness matching and meet the engineering application requirements of the aerospace field for achieving good strength-toughness matching of high-Nb-strength nickel-based superalloy parts under powder metallurgy process.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: On the one hand, see Figure 1 This invention provides a method for preparing high-Nb-strength nickel-based superalloy parts with excellent strength and plasticity matching, comprising the following steps: Step 1: Homogenize the GH4061 high-temperature alloy master alloy bar material with heat treatment. Step 2: The bar stock after homogenization and heat treatment in Step 1 is made into alloy powder, and pre-treated to obtain GH4061 alloy powder with a set particle size range. Step 3: The GH4061 alloy powder obtained in Step 2 is loaded into a prefabricated sleeve, and after degassing and sealing, the entire sleeve is pre-deformed to obtain a pre-deformed billet. Step 4: Perform composite hot isostatic pressing on the pre-deformed billet obtained in Step 3 to obtain powder metallurgy billet; Step 5: Heat treat the powder metallurgy billet obtained in Step 4, and after cooling, remove the cladding by machining to obtain GH4061 high-temperature alloy parts.

[0010] Furthermore, in step one, the GH4061 high-temperature alloy master alloy bar is prepared by vacuum induction melting.

[0011] Furthermore, in step one, the process parameters for the homogenization heat treatment are: temperature 1160℃~1200℃, time 4h~8h, and cooling method is air cooling.

[0012] Specifically, by rationally controlling the homogenization temperature and time, the internal elemental homogenization of the master alloy bar can be ensured. In powder metallurgy, although rapid solidification can significantly suppress macroscopic segregation, the powder preparation process itself may still introduce microscopic compositional inhomogeneities. Specifically, when alloy droplets are atomized, low-melting-point regions enriched between dendrites preferentially escape from the droplet surface or solidify, resulting in localized Nb enrichment in some powder particles. These Nb-rich powder particles are difficult to completely dissolve during subsequent hot isostatic pressing, but remain in the alloy microstructure as spherical residual dendrites. In the subsequent heat treatment stage, although these residual dendrites partially dissolve, the released Nb elements diffuse towards the original particle boundaries, thereby forming harmful phases at the grain boundaries or reducing local compositional homogenization, ultimately impairing the mechanical properties and service reliability of the alloy. Therefore, homogenization heat treatment of the master alloy bar before atomization powder preparation is essential. After homogenization, the master alloy exhibits a more uniform compositional distribution within the droplets during subsequent atomization, significantly reducing the formation of Nb-rich powder particles and suppressing the formation of spherical residual dendrites at its source. Simultaneously, it effectively avoids the exacerbation of PPB (polybutadiene oxidative stress) caused by Nb diffusion from spherical residual dendrites during subsequent heat treatment. Furthermore, it provides a homogeneous matrix for the uniform dispersion and precipitation of the γ″ phase, suppressing the heterogeneous nucleation tendency of the γ″ phase from the material supply side.

[0013] Further, in step two, alloy powder is prepared by plasma rotating electrode method or gas atomization method, and then the alloy powder is subjected to sieving and magnetic separation to remove impurities in sequence to obtain GH4061 high temperature alloy powder with a size of 53μm~106μm.

[0014] Furthermore, in step three, the sheath is made of stainless steel, and is suitable for vacuum conditions <1×10⁻⁶. -3 The powder is filled into the packaging under Pa conditions, and then degassed by vibration at a temperature of 400℃~460℃ for 4h~10h. After degassed, the powder filling port is sealed by electron beam welding.

[0015] Furthermore, in step three, the pre-deformation process includes: pressing the sealing sleeve at room temperature using a forging press, with a pressing pressure of 100MPa~200MPa and a holding time of 5min~15min.

[0016] Specifically, the pre-deformation treatment plays a dual role in this preparation method: on the one hand, it mechanically breaks down the oxide film on the powder surface to eliminate its adverse effects on subsequent densification and interfacial bonding; on the other hand, it introduces a high-density dislocation network into the powder particles inside the cladding. These pre-placed dislocations are partially retained in the subsequent solid solution treatment, becoming preferential sites for the uniform nucleation of the γ″ phase within the grains. This effectively guides the γ″ phase to precipitate diffusely within the grains, preventing it from agglomerating and nucleating at grain boundaries or residual interfaces. As a result, a uniform distribution of high-density, fine γ″ phases within the grains is achieved, laying the microstructural foundation for the strength and toughness matching of the alloy.

[0017] Optionally, the forging equipment may be a forging machine or a hydraulic press.

[0018] Furthermore, in step four, the composite hot isostatic pressing process includes first processing the pre-deformed billet in a high-temperature and low-pressure stage, then reducing the temperature to the medium-temperature and high-pressure stage at a set cooling rate, and simultaneously increasing the pressure to the medium-temperature and high-pressure stage at a set pressure increase rate, and then cooling it with the furnace after heat preservation and pressure holding.

[0019] Furthermore, the specific parameters for the high temperature and low pressure stage are: temperature 1220℃~1240℃, pressure 90MPa~120MPa, and heat and pressure holding time 0.5h~1.5h; the specific parameters for the medium temperature and high pressure stage are: temperature 1120℃~1180℃, pressure 150MPa~180MPa, and heat and pressure holding time 2h~6h. The cooling rate is 1℃ / min to 5℃ / min; the pressurization rate is 1MPa / min to 3MPa / min.

[0020] Specifically, a composite hot isostatic pressing (HIP) process of "high temperature, low pressure, short time + medium temperature, high pressure, long time" is employed. First, a short-time treatment is performed under high temperature and low pressure conditions close to the material's initial melting temperature. The high temperature promotes element diffusion, effectively breaking down and dispersing PPB. Then, the temperature is lowered to the medium temperature range while maintaining high pressure for a long-time treatment. While avoiding excessive grain growth, this process achieves complete closure of internal pores and full densification of the microstructure through sufficient diffusion creep and grain boundary slip mechanisms. This process, through the synergistic effect of "high temperature, short-time cell disruption" and "medium temperature, long-time densification," effectively eliminates PPB while precisely suppressing abnormal grain growth, achieving controllable preservation of fine-grained structures. This lays the microstructural foundation for the synergistic optimization of the material's mechanical properties.

[0021] Furthermore, in step five, the heat treatment process is solution treatment + two-stage aging treatment, with specific process parameters as follows: (960~1020)℃×(1~2)h / air cooling + (740~760)℃×(14.5~15.5)h / air cooling + (640~660)℃×(9.5~10.5)h / air cooling.

[0022] Specifically, the solution treatment temperature is chosen to be slightly higher than the complete dissolution temperature of γʹʹ and γʹ phases. Combined with short-term holding, this ensures the re-dissolution of γʹʹ and γʹ phases while avoiding damage to the fine-grained structure obtained by composite hot isostatic pressing. Simultaneously, it allows the partially dissolved residual brittle carbides and non-equilibrium phases precipitated during cooling in the composite hot isostatic pressing billet to be re-dissolved into the γ matrix, achieving a uniform distribution of strengthening elements such as Nb and Ti, providing a homogeneous matrix for subsequent aging precipitation. The subsequent first-stage aging treatment, through prolonged holding, promotes the uniform and dispersed precipitation of γʹʹ and γʹ phases from the γ matrix, forming a strong coherent strain field that effectively pins dislocations, laying the foundation for the alloy's high-temperature strength and room-temperature yield strength. Secondary aging serves as a supplement, on the one hand, further precipitating finer γʹʹ phases to compensate for the uneven distribution that may exist in primary aging, optimizing the ratio and size distribution of γʹʹ / γʹ phases, and reducing precipitation-depleted areas near grain boundaries; on the other hand, by improving the morphology of grain boundary precipitates, it significantly enhances the alloy's plasticity, impact toughness, and high-temperature creep resistance.

[0023] On the other hand, the present invention also provides a GH4061 high-temperature alloy part with excellent strength and plasticity matching, which is prepared based on the preparation method of the high-Nb-strength nickel-based high-temperature alloy part with excellent strength and plasticity matching as described above.

[0024] Furthermore, the GH4061 high-temperature alloy parts exhibit the following properties at -196℃: tensile strength > 1720 MPa, yield strength > 1210 MPa, elongation > 35%, and reduction of area > 35%; at 650℃: tensile strength > 1100 MPa, yield strength > 850 MPa, elongation > 25%, and reduction of area > 30%; at 750℃ / 500 MPa: smooth creep life > 5.5 h; and room temperature impact energy > 78 J.

[0025] Furthermore, this invention also provides an application based on the GH4061 high-temperature alloy component described above, which is used in the manufacture of key components for liquid oxygen rocket engines, such as oxygen-enriched collectors and fuel-enriched collectors.

[0026] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention employs a powder metallurgy approach, utilizing rapid solidification technology to fundamentally suppress macroscopic and microscopic segregation of elements such as Nb, avoiding the formation of low-melting-point Laves phases and significantly broadening the hot working window. Simultaneously, the high consistency of powder particle composition and microstructure eliminates ingot microstructure differences, facilitating precise control of subsequent processes and ensuring stable performance between batches of manufactured parts. Furthermore, powder metallurgy offers near-net-shape forming capabilities, with material utilization exceeding 90%, effectively reducing production costs and demonstrating excellent economic viability and promising engineering application prospects.

[0027] 2. This invention addresses the technical characteristics of GH4061 alloy, which has a high Nb content and is prone to forming spherical residual dendrites during powder metallurgy, exacerbating the PPB problem. It addresses this by performing a homogenization heat treatment on the master alloy before atomization. This treatment effectively eliminates the dendritic structure and low-melting-point eutectic phase formed by the segregation of Nb and other elements in the ingot, making the alloy composition more uniform at both the macroscopic and microscopic scales. This significantly reduces the formation of Nb-rich powder particles during atomization. On one hand, this inhibits the formation of spherical residual dendrites in the part from the source, avoiding the exacerbation of the PPB problem caused by the diffusion of Nb into the PPB during subsequent heat treatment. On the other hand, the homogenized matrix provides the material conditions for the uniform dispersion and precipitation of the γ″ phase, significantly suppressing the tendency of the γ″ phase to nucleate heterogeneously.

[0028] 3. This invention achieves full-process control of PPB and fine regulation of the γ″ strengthening phase through the coordinated process of "homogenization pretreatment - pre-deformation - composite hot isostatic pressing - heat treatment". Homogenization treatment reduces the material supply of PPB strengthening phase at the source and provides a compositionally uniform matrix for the uniform precipitation of γ″ phase; the high-density dislocations introduced by pre-deformation provide preferential nucleation sites for γ″ phase within the grain; composite hot isostatic pressing eliminates residual PPB and retains fine-grained structure; subsequent solid solution + two-stage aging treatment further optimizes the ratio, size and distribution of γ″ / γ' phase, forming a strong coherent strain field. The powder metallurgy GH4061 alloy parts prepared by this invention exhibit excellent comprehensive mechanical properties over a wide temperature range: Low temperature (-196℃): tensile strength > 1720 MPa, yield strength > 1210 MPa, elongation > 35%, reduction of area > 39%; High temperature (650℃): tensile strength > 1100 MPa, yield strength > 850 MPa, elongation > 25%, reduction of area > 30%; High temperature creep rupture performance: smooth creep life > 5.5 h at 750℃ / 500 MPa; Room temperature toughness: impact energy > 78 J. These performance indicators fully demonstrate that this invention achieves a synergistic improvement in strength, plasticity, and impact toughness, meeting the service requirements under extreme conditions.

[0029] In summary, this invention addresses the strength-toughness inversion problem caused by polymorphic barrier phase (PPB) in high-Nb-strength nickel-based superalloy powder metallurgy. It achieves full-process control of the γ'' strengthening phase through pretreatment to homogenize the parent alloy, pre-deformation to introduce dislocation-induced uniform nucleation of γ'' grains, combined hot isostatic pressing ("high temperature, low pressure, short time + medium temperature, high pressure, long time") to eliminate PPB while preserving fine-grained microstructure, and precise heat treatment to optimize the γ'' / γ' precipitates. This provides a solution for preparing high-performance high-Nb-strength nickel-based superalloy components for critical aerospace components such as liquid oxygen rocket engines, characterized by uniform microstructure, effective PPB elimination, controllable preservation of fine grains, and excellent synergistic strength and toughness. Attached Figure Description

[0030] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0032] Figure 1 A flowchart illustrating the preparation method of a high-Nb-strength nickel-based superalloy part with excellent strength-plasticity matching provided by the present invention. Figure 2The microstructure of the GH4061 high-temperature alloy master alloy bar is as-cast and has not undergone homogenization heat treatment. Figure 3 The as-cast microstructure of GH4061 high-temperature alloy master alloy bar after homogenization heat treatment; Figure 4 The internal PPB morphology of the GH4061 high-temperature alloy part prepared in Example 2 of this invention; Figure 5 The internal PPB morphology of the GH4061 high-temperature alloy part prepared in Comparative Example 1 is shown. Figure 6 The internal PPB morphology of the GH4061 high-temperature alloy part prepared in Comparative Example 2 is shown. Figure 7 The grain size of the GH4061 high-temperature alloy part prepared in Example 2 of this invention; Figure 8 The grain size of the GH4061 high-temperature alloy part prepared in Comparative Example 1; Figure 9 The grain size of the GH4061 high-temperature alloy part prepared in Comparative Example 2; Figure 10 The high-temperature tensile fracture morphology of the GH4061 high-temperature alloy part prepared in Example 2 of the present invention; Figure 11 The high-temperature tensile fracture morphology of the GH4061 high-temperature alloy part prepared in Comparative Example 1 is shown. Figure 12 The high-temperature tensile fracture morphology of the GH4061 high-temperature alloy part prepared in Comparative Example 2 is shown. Detailed Implementation

[0033] Exemplary embodiments will now be described in detail. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.

[0034] Example 1 This embodiment provides a method for preparing a high-Nb-strength GH4061 high-temperature alloy part with excellent strength-plasticity matching, specifically including the following steps: Step 1: The GH4061 high-temperature alloy master alloy bar prepared by vacuum induction melting is subjected to homogenization heat treatment. The specific process parameters are: temperature 1160℃, time 8h, and cooling method is air cooling.

[0035] Step 2: The rod material homogenized and heat-treated in Step 1 is used to prepare alloy powder using the plasma rotating electrode method. The alloy powder is then subjected to sieving and magnetic separation to remove impurities, resulting in GH4061 high-temperature alloy powder with a particle size range of 53 μm to 106 μm.

[0036] Step 3: The GH4061 high-temperature alloy powder obtained in Step 2 is placed into a stainless steel sleeve and subjected to a vacuum degree <1×10⁻⁶. -3 Powder was loaded under Pa conditions, followed by vibration degassing at a temperature of 400℃ for 10 hours. After degassing, the powder loading port was sealed with an electron beam. Then, the sealing sleeve was pre-deformed at room temperature using a forging machine to obtain a pre-deformed billet. The pressing pressure was 100 MPa and the holding time was 15 minutes.

[0037] Step 4: The pre-deformed billet obtained in Step 3 is subjected to composite hot isostatic pressing treatment. This treatment consists of a high-temperature and low-pressure stage and a medium-temperature and high-pressure stage. The specific process is as follows: First, the pre-deformed billet is held at 1240℃ and 120MPa for 0.5h. After the holding time, the temperature is reduced to 1180℃ at a rate of 1℃ / min while maintaining the pressure, and the pressure is increased to 180MPa at a rate of 1MPa / min for 2h. After the composite hot isostatic pressing treatment is completed, the billet is cooled in the furnace to obtain powder metallurgy billet.

[0038] Step 5: The powder metallurgy billet obtained in Step 4 is subjected to solution treatment and two-stage aging heat treatment. The specific process is as follows: 960℃×2h / air cooling + 740℃×15.5h / air cooling + 640℃×10.5h / air cooling. After that, the cladding is removed by machining to obtain high-performance GH4061 high-temperature alloy parts.

[0039] Example 2 This embodiment provides a method for preparing a high-Nb-strength GH4061 high-temperature alloy part with excellent strength-plasticity matching, specifically including the following steps: Step 1: The GH4061 high-temperature alloy master alloy bar prepared by vacuum induction melting is subjected to homogenization heat treatment. The specific process parameters are: temperature 1180℃, time 6h, and cooling method is air cooling.

[0040] Step 2: The rod material homogenized and heat-treated in Step 1 is used to prepare alloy powder using the plasma rotating electrode method. The alloy powder is then subjected to sieving and magnetic separation to remove impurities, resulting in GH4061 high-temperature alloy powder with a particle size range of 53 μm to 106 μm.

[0041] Step 3: The GH4061 high-temperature alloy powder obtained in Step 2 is placed into a stainless steel sleeve and subjected to a vacuum degree <1×10⁻⁶. -3Powder was loaded under Pa conditions, followed by vibration degassing at a temperature of 440℃ for 8 hours. After degassing, the powder loading port was sealed with an electron beam. Then, the sealing sleeve was pre-deformed at room temperature using a forging machine to obtain a pre-deformed billet. The pressing pressure was 150 MPa and the holding time was 10 minutes.

[0042] Step 4: The pre-deformed billet obtained in Step 3 is subjected to composite hot isostatic pressing treatment. This treatment consists of a high-temperature and low-pressure stage and a medium-temperature and high-pressure stage. The specific process is as follows: First, the pre-deformed billet is held at 1230℃ and 105MPa for 1 hour. After the holding time, the temperature is reduced to 1150℃ at a rate of 3℃ / min while maintaining the pressure, and the pressure is increased to 160MPa at a rate of 2MPa / min for 4 hours. After the composite hot isostatic pressing treatment is completed, the billet is cooled in the furnace to obtain powder metallurgy billet.

[0043] Step 5: The powder metallurgy billet obtained in Step 4 is subjected to solution treatment and two-stage aging heat treatment. The specific process is: 990℃×1.5h / air cooling + 750℃×15h / air cooling + 650℃×10h / air cooling. After that, the cladding is removed by machining to obtain high-performance GH4061 high-temperature alloy parts.

[0044] Example 3 This embodiment provides a method for preparing a high-Nb-strength GH4061 high-temperature alloy part with excellent strength-plasticity matching, specifically including the following steps: Step 1: The GH4061 high-temperature alloy master alloy bar prepared by vacuum induction melting is subjected to homogenization heat treatment. The specific process parameters are: temperature 1200℃, time 4h, and cooling method is air cooling.

[0045] Step 2: The rod material homogenized and heat-treated in Step 1 is used to prepare alloy powder using the plasma rotating electrode method. The alloy powder is then subjected to sieving and magnetic separation to remove impurities, resulting in GH4061 high-temperature alloy powder with a particle size range of 53 μm to 106 μm.

[0046] Step 3: The GH4061 high-temperature alloy powder obtained in Step 2 is placed into a stainless steel sleeve and subjected to a vacuum degree <1×10⁻⁶. -3 Powder was loaded under Pa conditions, followed by vibration degassing at a temperature of 460℃ for 4 hours. After degassing, the powder loading port was sealed with an electron beam. Then, the sealing sleeve was pre-deformed at room temperature using a forging machine to obtain a pre-deformed billet. The pressing pressure was 200 MPa and the holding time was 5 minutes.

[0047] Step 4: The pre-deformed billet obtained in Step 3 is subjected to composite hot isostatic pressing treatment. This treatment consists of a high-temperature and low-pressure stage and a medium-temperature and high-pressure stage. The specific process is as follows: First, the pre-deformed billet is held at 1220℃ and 90MPa for 1.5 hours. After the holding time, the temperature is reduced to 1120℃ at a rate of 5℃ / min while maintaining the pressure, and the pressure is increased to 150MPa at a rate of 3MPa / min for 6 hours. After the composite hot isostatic pressing treatment is completed, the billet is cooled in the furnace to obtain powder metallurgy billet.

[0048] Step 5: The powder metallurgy billet obtained in Step 4 is subjected to solution treatment and two-stage aging heat treatment. The specific process is as follows: 1020℃×1h / air cooling + 760℃×14.5h / air cooling + 660℃×9.5h / air cooling. After that, the cladding is removed by machining to obtain high-performance GH4061 high-temperature alloy parts.

[0049] Comparative Example 1 This comparative example provides a method for preparing a high-Nb strengthened GH4061 high-temperature alloy part, specifically including the following steps: Step 1: Select GH4061 high-temperature alloy master alloy rods prepared by vacuum induction melting method, then prepare GH4061 alloy powder by plasma rotating electrode method, and then perform sieving and magnetic separation to remove impurities in sequence to obtain GH4061 high-temperature alloy powder with a particle size range of 53μm~106μm.

[0050] Step 2: The GH4061 high-temperature alloy powder obtained in Step 1 is placed into a stainless steel sleeve and subjected to a vacuum degree <1×10⁻⁶. -3 Powder was loaded under Pa conditions, followed by vibration degassing at 440℃ for 8 hours. After degassing, the powder loading port was sealed with an electron beam. Then, hot isostatic pressing (HIP) was performed at 1150℃ and 160MPa for 4 hours. After HIP, the powder was cooled in the furnace to obtain GH4061 powder metallurgy billet.

[0051] Step 3: The GH4061 powder metallurgy billet obtained in Step 2 is subjected to solution treatment and two-stage aging heat treatment. The specific process is: 990℃×1.5h / air cooling + 750℃×15h / air cooling + 650℃×10h / air cooling. After that, the cladding is removed by machining to obtain the GH4061 high-temperature alloy part.

[0052] Comparative Example 2 This comparative example provides a method for preparing a high-Nb strengthened GH4061 high-temperature alloy part, specifically including the following steps: Step 1: Select GH4061 high-temperature alloy master alloy rods prepared by vacuum induction melting method, then prepare GH4061 alloy powder by plasma rotating electrode method, and then perform sieving and magnetic separation to remove impurities in sequence to obtain GH4061 high-temperature alloy powder with a particle size range of 53μm~106μm.

[0053] Step 2: The GH4061 high-temperature alloy powder obtained in Step 1 is placed into a stainless steel sleeve and subjected to a vacuum degree <1×10⁻⁶. - 3 Powder was loaded under Pa conditions, followed by vibration degassing at 440℃ for 8 hours. After degassing, the powder loading port was sealed with an electron beam. Then, hot isostatic pressing (HIP) was performed at 1240℃ and 160MPa for 4 hours. After HIP, the powder was cooled in the furnace to obtain GH4061 powder metallurgy billet.

[0054] Step 3: The GH4061 powder metallurgy billet obtained in Step 2 is subjected to solution treatment and two-stage aging heat treatment. The specific process is: 990℃×1.5h / air cooling + 750℃×15h / air cooling + 650℃×10h / air cooling. After that, the cladding is removed by machining to obtain the GH4061 high-temperature alloy part.

[0055] Combination Figure 2 and Figure 3 It can be seen that after homogenization heat treatment, the cast dendritic structure in the GH4061 high-temperature alloy master alloy bar has been completely eliminated, and the element distribution tends to be homogenized.

[0056] contrast Figures 4-6 It can be seen that the carbide distribution inside the part prepared by the present invention is uniform, the amount of PPB is small and the boundary is blurred. Figure 4 ); while the parts prepared in Comparative Examples 1 and 2 had a large number of residual dendrites remaining ( Figure 5 , Figure 6 Furthermore, as the hot isostatic pressing temperature increases, the residual dendrites partially dissolve, releasing Nb elements that diffuse towards the PPB, resulting in a significant increase in the number of PPBs and clearer boundaries. Figure 6 This will severely impair the mechanical properties of the material.

[0057] Depend on Figures 7-9 It can be seen that the short-time high-temperature low-pressure hot isostatic pressing treatment in Example 2 of the present invention did not lead to significant grain growth in the alloy, and its average grain size was 51.71 μm. Figure 7 ),and Figure 8 The average grain size of the parts formed after conventional medium-temperature hot isostatic pressing in Comparative Example 1 (50.71 μm) is basically the same; while the average grain size of the parts formed after conventional high-temperature hot isostatic pressing in Comparative Example 2 is significantly increased to 91.78 μm. Figure 9 This indicates that the composite hot isostatic pressing (HIP) process of "high temperature, low pressure, short time + medium temperature, high pressure, long time" has overcome the technical limitations of traditional single-stage HIP, which makes it difficult to simultaneously eliminate PPB and control grain size. It effectively eliminates PPB while achieving the controllable retention of fine-grained structures.

[0058] Furthermore, to verify the efficacy of the present invention, the inventors also conducted low-temperature tensile testing at -196℃ (GB / T 228.2), high-temperature tensile testing at 650℃ (GB / T 228.2), smooth durability testing at 750℃ / 500 MPa (GB / T 2039), and room-temperature impact testing on the GH4061 powder metallurgy parts prepared in the embodiments and comparative examples of the present invention. The specific test results are shown in Tables 1 to 3 below.

[0059] Table 1. Low-temperature and high-temperature tensile properties of GH4061 alloy parts in the Examples and Comparative Examples Table 2. High-temperature creep performance of GH4061 alloy parts at 750°C in the Examples and Comparative Examples Table 3. Room temperature impact properties of GH4061 alloy parts in the Examples and Comparative Examples The test results above show that the powder metallurgy GH4061 alloy parts prepared by this invention exhibit excellent comprehensive mechanical properties over a wide temperature range. Deep low temperature (-196℃): tensile strength > 1720 MPa, yield strength > 1210 MPa, elongation > 35%, reduction of area > 35%; High temperature (650℃): Tensile strength > 1100 MPa, yield strength > 850 MPa, elongation > 25%, reduction of area > 30%; High-temperature creep resistance: Smooth creep life > 5.5 h under 750℃ / 500 MPa conditions; Room temperature toughness: Impact energy > 78 J.

[0060] The above performance indicators fully demonstrate that the present invention achieves a synergistic improvement in strength, plasticity, and impact toughness, meeting the service requirements under extreme working conditions. Combined with... Figures 10-12 It can be seen that the high-temperature tensile fracture surface of the present invention exhibits ductile transgranular fracture (…). Figure 10 The high-temperature tensile fracture surface in the comparative example exhibits typical intergranular fracture characteristics, with some areas showing fracture along the PPB (polypeptide-polyester) axis. Figure 11 , Figure 12This indicates that the present invention effectively eliminates the brittle phase at the original particle boundaries through a composite hot isostatic pressing process of "high temperature, low pressure, short time + medium temperature, high pressure, long time", transforming the fracture mechanism from intergranular brittle fracture to transgranular ductile fracture. This fundamentally improves the plasticity and toughness of the alloy from the fracture mechanism level, achieving synergistic optimization of the strength and toughness of powder metallurgy GH4061 alloy parts.

[0061] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0062] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing a high-Nb-strength nickel-based superalloy part with excellent strength and ductility matching, characterized in that, Includes the following steps: Step 1: Homogenize the GH4061 high-temperature alloy master alloy bar material with heat treatment. Step 2: The bar stock after homogenization and heat treatment in Step 1 is made into alloy powder, and pre-treated to obtain GH4061 alloy powder with a set particle size range. Step 3: The GH4061 alloy powder obtained in Step 2 is loaded into a prefabricated sleeve, and after degassing and sealing, the entire sleeve is pre-deformed to obtain a pre-deformed billet. Step 4: Perform composite hot isostatic pressing on the pre-deformed billet obtained in Step 3 to obtain powder metallurgy billet; Step 5: Heat treat the powder metallurgy billet obtained in Step 4, and after cooling, remove the cladding by machining to obtain GH4061 high-temperature alloy parts.

2. The method for preparing high-Nb-strength reinforced nickel-based superalloy parts with excellent strength and plasticity matching according to claim 1, characterized in that, In step one, the process parameters for the homogenization heat treatment are: temperature 1160℃~1200℃, time 4h~8h, and cooling method is air cooling.

3. The method for preparing high-Nb-strength reinforced nickel-based superalloy parts with excellent strength and plasticity matching according to claim 1, characterized in that, In step two, alloy powder is prepared by plasma rotating electrode method or gas atomization method, and then the alloy powder is subjected to sieving and magnetic separation to remove impurities in sequence to obtain GH4061 high temperature alloy powder with a size of 53μm~106μm.

4. The method for preparing high-Nb-strength reinforced nickel-based superalloy parts with excellent strength and plasticity matching according to claim 1, characterized in that, In step three, the pre-deformation process includes: pressing the sealing sleeve at room temperature using a forging press, with a pressing pressure of 100MPa~200MPa and a holding time of 5min~15min.

5. The method for preparing high-Nb-strength reinforced nickel-based superalloy parts with excellent strength and plasticity matching according to claim 1, characterized in that, In step four, the composite hot isostatic pressing process includes first processing the pre-deformed billet in a high temperature and low pressure stage, then reducing the temperature to the medium temperature and high pressure stage at a set cooling rate, and simultaneously increasing the pressure to the medium temperature and high pressure stage at a set pressure increase rate, and then cooling it with the furnace after heat preservation and pressure holding.

6. The method for preparing high-Nb-strength reinforced nickel-based superalloy parts with excellent strength and plasticity matching according to claim 5, characterized in that, The specific parameters for the high temperature and low pressure stage are: temperature 1220℃~1240℃, pressure 90MPa~120MPa, and heat and pressure holding time 0.5h~1.5h; the specific parameters for the medium temperature and high pressure stage are: temperature 1120℃~1180℃, pressure 150MPa~180MPa, and heat and pressure holding time 2h~6h. The cooling rate is 1℃ / min to 5℃ / min; the pressurization rate is 1MPa / min to 3MPa / min.

7. The method for preparing high-Nb-strength reinforced nickel-based superalloy parts with excellent strength and plasticity matching according to claim 5, characterized in that, In step five, the heat treatment process is solution treatment + two-stage aging treatment, with specific process parameters as follows: (960~1020)℃×(1~2)h / air cooling + (740~760)℃×(14.5~15.5)h / air cooling + (640~660)℃×(9.5~10.5)h / air cooling.

8. A GH4061 high-temperature alloy part with excellent strength and plasticity, characterized in that, The high-Nb-strength nickel-based superalloy parts with excellent strength and plasticity matching as described in any one of claims 1 to 7 were prepared.

9. The GH4061 high-temperature alloy part with excellent strength and plasticity matching according to claim 8, characterized in that, The GH4061 high-temperature alloy parts exhibit the following properties at -196℃: tensile strength > 1720 MPa, yield strength > 1210 MPa, elongation > 35%, and reduction of area > 35%; at 650℃: tensile strength > 1100 MPa, yield strength > 850 MPa, elongation > 25%, and reduction of area > 30%; at 750℃ / 500 MPa: smooth creep life > 5.5 h; and room temperature impact energy > 78 J.

10. An application of the GH4061 high-temperature alloy part according to claim 8 or 9, characterized in that, The GH4061 high-temperature alloy parts are used in the manufacture of key components for liquid oxygen rocket engines.

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