GH4169 powder for eliminating original particle boundary and preparation method and application thereof

Abstract

The invention belongs to the technical field of powder metallurgy, and particularly discloses GH4169 powder used for eliminating original particle boundaries and a preparation method and application thereof.The GH4169 powder is of a core-shell structure, standard GH4169 powder serves as a core, transition layer alloy powder serves as a shell, the shell reduces interface brittle phases by reducing the content of C and Si, and therefore the grain boundary is eliminated. Meanwhile, a B element is added to promote diffusion and strengthen an interface, and a core and a shell are matched in particle size to form a continuous transition layer; according to the preparation method, two kinds of powder are prepared through an argon atomization method, and then uniform coating is achieved through a fluidized bed coating process; and filling the powder into a sheath, and carrying out vacuum sealing and hot isostatic pressing treatment to obtain a GH4169 workpiece. The prepared GH4169 workpiece is free of original particle boundaries (PPB) and excellent in comprehensive mechanical property, the problem that performance of a traditional powder metallurgy workpiece is reduced due to PPB is effectively solved, and the GH4169 workpiece is suitable for the field of high-end equipment such as aerospace.

Description

Technical Field

[0001] The present invention belongs to the technical field of powder metallurgy, and in particular relates to a GH4169 powder for eliminating original particle boundaries, a preparation method and an application thereof. Background Art

[0002] GH4169 alloy is a typical precipitation-strengthened nickel-based high-temperature alloy. With its excellent tensile strength, fatigue performance, oxidation resistance and processability, it has become a key structural material in high-end equipment fields such as aerospace, nuclear energy, and petrochemicals. It is widely used in core components such as aircraft engine turbine disks, blades, combustion chambers, and nuclear reactor pressure vessels.

[0003] In recent years, with the increasing performance requirements of high-end equipment, powder metallurgy (PM) has become the mainstream manufacturing process for GH4169 alloy parts due to its ability to achieve near-net-net shape of complex structures and reduce compositional segregation. Hot isostatic pressing (HIP) has become the core process for PM GH4169 parts, thanks to its advantages in achieving full densification and uniform mechanical properties. However, the manufacturing process of PM GH4169 parts generally faces the problem of primary grain boundaries (PPBs). This is because compositional differences (such as element segregation and impurity enrichment) easily lead to the formation of brittle phases, mainly carbides (such as NbC) and silicides (such as SiO2), at the powder particle interfaces. These brittle phases are continuously distributed along the particle boundaries, significantly reducing the mechanical properties (such as strength, ductility, and toughness) of the parts. In severe cases, they can lead to sudden failure of the components during service, thus limiting the application reliability of PM GH4169 alloy.

[0004] To address the PPB problem, existing technologies have explored various approaches, but all have significant limitations, including the following: 1) Powder pretreatment techniques, such as vacuum degassing and plasma surface cleaning, can reduce gaseous impurities (such as O and N) adsorbed on the powder surface, but they cannot alter the compositional gradient of the powder particles themselves, making it difficult to fundamentally inhibit the nucleation and growth of interfacial brittle phases. 2) Hot isostatic pressing (HIP) process optimization: Increasing the temperature or extending the holding time can promote element diffusion, but this can lead to excessive grain coarsening, which in turn reduces the strength and toughness of the component, creating a performance conflict. 3) Subsequent heat treatment control: High-temperature solution treatment (typically exceeding 1100°C) can partially dissolve the brittle phases, but this consumes a great deal of energy, can easily cause component deformation, and requires stringent equipment precision, making it difficult to adapt to industrial production. Therefore, there is an urgent need to develop a technical solution that can fundamentally eliminate the brittle phases at the interface of GH4169 powder particles and suppress PPB through precise composition design and process control. This is of great significance for improving the mechanical properties and service reliability of powder metallurgy GH4169 components.

[0005] In view of this, this invention is proposed. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a GH4169 powder for eliminating primary particle boundaries, a preparation method and its application, which are mainly used to solve the problem of mechanical performance degradation caused by the existence of primary particle boundaries (PPB) in the preparation process of existing powder metallurgy GH4169 parts. Through the gradient core-shell structure design and supporting preparation process, the brittle phase at the particle interface is eliminated from the root, and the formation of PPB is inhibited, thereby achieving the purpose of improving the mechanical properties and service reliability of GH4169 parts.

[0007] The purpose of the present invention is to solve the problem through the following technical solutions:

[0008] In a first aspect, the present invention provides a GH4169 powder for eliminating original particle boundaries. The GH4169 powder adopts a core-shell structure, comprising a core and a shell covering the surface of the core, wherein the core is standard GH4169 powder and the shell is a transition layer alloy powder.

[0009] The composition of the standard GH4169 powder by mass percentage is: Cr: 17.0% to 21.0%, Ni: 50.0% to 55.0%, Nb: 4.75% to 5.50%, Mo: 2.8% to 3.3%, Ti: 0.65% to 1.15%, Al: 0.2% to 0.8%, C: 0.02% to 0.08%, Si: 0.3% to 0.7%, and the balance is Fe and unavoidable impurities;

[0010] The transition layer alloy powder has the following composition by mass percentage: Cr: 17.0% to 21.0%, Ni: 50.0% to 55.0%, Nb: 4.75% to 5.50%, Mo: 2.8% to 3.3%, Ti: 0.65% to 1.15%, Al: 0.2% to 0.8%, B: 0.005% to 0.02%, C≤0.02%, Si≤0.05%, and the balance is Fe and unavoidable impurities.

[0011] Furthermore, the particle size of the standard GH4169 powder is 50 μm to 150 μm, and the particle size of the transition layer alloy powder is 5 μm to 20 μm.

[0012] Preferably, the thickness of the shell is generally 5 μm to 30 μm.

[0013] Furthermore, in the transition layer alloy powder, unavoidable impurities include O≤0.015%, N≤0.01%, P≤0.01%, S≤0.005%, other single impurities≤0.005%, and total impurities≤0.03%.

[0014] It should be noted that the design of the GH4169 powder of the present invention is based on the principle of interface component regulation, specifically as follows:

[0015] 1) Mechanism for Reducing C and Si Content in the Transition Layer Alloy Powder: The C (0.02%-0.08%) and Si (0.3%-0.7%) content in standard GH4169 powder is the primary driver of primary particle boundary (PPB) formation, spurring the formation of brittle phases such as carbides (e.g., NbC) and silicides (e.g., SiO2) at the particle interfaces. Experimental results indicate that controlling the C content in the transition layer to ≤0.02% and the Si content to ≤0.05% significantly reduces the driving force for nucleation of brittle phases at the interface. However, when the C content exceeds 0.02% and the Si content exceeds 0.05%, the amount of brittle phase precipitation increases dramatically.

[0016] 2) The mechanism of action of the boron element (0.005%-0.02%) in the transition layer alloy powder: As a grain boundary strengthening element, boron preferentially accumulates at the particle interface, promoting elemental diffusion between the core and shell by reducing the interfacial energy, thereby enhancing interfacial bonding. Experiments have shown that controlling the boron content within the range of 0.005%-0.02% achieves a balance between promoting diffusion and preventing the formation of low-melting-point borides. When the boron content exceeds 0.02%, the Ni3B brittle phase appears.

[0017] 3) Core-shell particle size matching mechanism: A core with a particle size of 50μm to 150μm is matched with a shell with a particle size of 5μm to 20μm. The fine particle shell can completely cover the coarse particle core through physical coating to form a continuous transition layer, thereby avoiding composition mutations caused by direct contact between the cores.

[0018] In a second aspect, the present invention further provides a method for preparing the above-mentioned GH4169 powder, comprising the following steps:

[0019] Step 1: prepare standard GH4169 powder and transition layer alloy powder respectively;

[0020] Step 2: placing the standard GH4169 powder in a fluidized bed coating device, introducing an inert gas as a carrier gas to fluidize the standard GH4169 powder; then feeding the transition layer alloy powder into the fluidized bed coating device at a preset rate, so that the transition layer alloy powder is evenly coated on the surface of the standard GH4169 powder, thereby obtaining the GH4169 powder.

[0021] Furthermore, in step 1, the standard GH4169 powder and the transition layer alloy powder are both prepared by argon atomization method;

[0022] Wherein, when preparing the standard GH4169 powder, the atomization pressure is 6MPa-8MPa, and the atomization temperature is 1500℃-1600℃;

[0023] When preparing the transition layer alloy powder, the atomization pressure is 7MPa-9MPa, and the atomization temperature is 1550°C-1650°C.

[0024] Furthermore, in step 2, the ratio of the flow rate of the inert gas to the feed rate of the transition layer alloy powder is (10-40):1, the operating temperature of the fluidized bed coating equipment is 80°C-120°C, and the coating time is 2h-4h.

[0025] Furthermore, in step 2, the flow rate of the inert gas is 10 L / min to 20 L / min, and the feed rate of the transition layer alloy powder is 0.5 g / min to 1.0 g / min.

[0026] In the preparation method of GH4169 powder of the present invention, the core is to achieve uniform adhesion of the shell and the core through a fluidized state. The specific mechanism is as follows:

[0027] 1) Fluidization: An inert gas (such as argon) is introduced into the fluidized bed coating equipment at a flow rate of 10-20 L / min, maintaining a suspended, tumbling "fluidized" state for the core standard GH4169 powder with a particle size of 50-150 μm. This state eliminates agglomeration between core particles and provides uniform force in all directions, providing a stable physical foundation for uniform shell coating.

[0028] 2) Shell (transition layer alloy powder) adhesion mechanism: After being carried by the airflow into the fluidized bed coating equipment, the fine-particle transition layer alloy powder with a particle size of 5 to 20 μm undergoes continuous mechanical collisions with the fluidized core powder. During this collision, the transition layer alloy powder uniformly adheres to the core surface through physical interactions such as van der Waals forces and electrostatic adsorption, forming a preliminary core-shell structure.

[0029] 3) Coordinated Control of Process Parameters: By controlling the ratio of the inert gas flow rate to the transition layer alloy powder feed rate ((10-40):1), the shell powder adhesion efficiency can be precisely adjusted, ensuring that the fine-particle shell evenly covers the core surface and effectively avoiding local agglomeration. Furthermore, the operating temperature of the fluidized bed coating equipment is controlled to 80°C to 120°C, and the coating time is controlled to 2h to 4h: this temperature environment prevents powder sintering during the coating process, while sufficient coating time ensures uniform shell thickness. Experiments have shown that a coating time of 2h to 4h can control the shell thickness deviation to within ±2μm, ultimately forming a stable core-shell structure.

[0030] In a third aspect, the present invention provides a method for preparing a GH4169 part, comprising the following steps:

[0031] Step 1: Place the GH4169 powder into a prefabricated bag;

[0032] Step 2: Vacuum the package until the vacuum degree is ≤5×10 -4 Sealing the package at Pa;

[0033] Step 3: The sealed package is subjected to hot isostatic pressing, and then subjected to standard solution treatment and aging heat treatment (existing technology, which will not be described in detail) to obtain the GH4169 product.

[0034] Furthermore, in step 1, the material of the sheath is stainless steel.

[0035] Furthermore, in step 3, the process parameters of the hot isostatic pressing treatment are as follows: temperature of 1100°C to 1200°C, pressure of 100MPa to 150MPa, holding time of 2h to 4h, and cooling rate of 5°C / min to 10°C / min.

[0036] In a fourth aspect, the present invention also provides a GH4169 part, which is prepared by the above-mentioned preparation method. The GH4169 part has a uniform metallographic structure, no primary grain boundaries (PPB), and mechanical properties that meet the following requirements: tensile strength > 1400 MPa, yield strength > 1130 MPa, and elongation ≥ 20%.

[0037] It should be noted that in the preparation of GH4169 parts in the present invention, hot isostatic pressing is a key step in achieving interface fusion of the core-shell structure and eliminating the original particle boundaries. Its core mechanism is as follows:

[0038] 1) Preferential softening / melting of the transition layer: The hot isostatic pressing temperature (1100°C-1200°C) is close to the solidus of the transition layer alloy, but below the melting point of the core GH4169 (greater than 1260°C). This causes the outer shell (transition layer alloy powder) to soften or partially melt before the core. This process fills the gaps between the core particles, forming a continuous diffusion medium and providing a path for subsequent element migration.

[0039] 2) Element Diffusion Eliminates Gradients: Under pressures of 100-150 MPa, the elements in the core and shell diffuse along the concentration gradient. Specifically, the higher concentrations of C and Si in the core diffuse toward the transition layer (C ≤ 0.02%, Si ≤ 0.05%), utilizing the concentration difference to drive the homogenization of the brittle phase-forming elements. The boron element in the transition layer diffuses toward the core, preferentially concentrating at the interface and reducing interfacial energy, promoting cross-interface atomic migration and eliminating compositional abrupt changes.

[0040] 3) Interface metallurgical bonding: After 2h to 4h of heat preservation and pressure holding, the interface between the core and the shell is transformed from a physical attachment state to a metallurgical bond. Through the full diffusion of elements, the composition gradient at the interface disappears, and the primary particle boundary (PPB) cannot be generated due to the loss of the conditions for the formation of the brittle phase, ultimately significantly improving the mechanical properties of the part.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The GH4169 powder provided by the present invention, through a gradient core-shell structure design, breaks through the technical bottleneck of "compositional mutation leading to PPB" in traditional powder metallurgy. The core is standard GH4169 powder, and the shell is a transition layer alloy powder. The transition layer alloy powder blocks the nucleation conditions of brittle phases such as carbides and silicides from the source by reducing the C and Si contents (C≤0.02%, Si≤0.05%). At the same time, a set amount of B element (0.005% to 0.02%) is added to promote diffusion bonding between particles and strengthen interface properties. Compared with the existing core-shell structure that is prone to introducing heterogeneous interface defects, it can achieve a more seamless transition of composition. Experimental verification has shown that this design can completely eliminate the original particle boundary (PPB), solving the problem that traditional pretreatment technology cannot eradicate the composition gradient.

[0043] 2. In preparing GH4169 powder, this invention uses argon atomization to grade the core-shell powder. The outer shell (transition layer alloy powder) is prepared at higher pressures and temperatures than those used for standard GH4169 powder to ensure powder purity and particle size distribution. Furthermore, a fluidized bed coating process ensures that the transition layer alloy powder is evenly coated on the surface of the standard GH4169 powder (with an outer shell thickness tolerance of ±2μm), ensuring the quality stability of the GH4169 powder.

[0044] 3. The GH4169 parts provided by this invention utilize a core-shell GH4169 powder structure combined with a hot isostatic pressing diffusion mechanism (preferential softening / melting of the transition layer → gradient element migration, filling interparticle gaps and acting as a diffusion medium → interface metallurgical bonding). The resulting GH4169 parts are PPB-free and exhibit mechanical properties superior to those achieved by conventional methods. Field testing demonstrates tensile strength >1400 MPa, yield strength >1130 MPa, and elongation ≥20%. These parts can be directly used in key components such as aircraft engine turbine disks, significantly improving service safety compared to existing products. Furthermore, this invention is applicable not only to GH4169 alloy but also to other powder metallurgy superalloy systems prone to PPB formation (such as GH3536 and GH4738). BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the invention.

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0047] Figure 1 Schematic diagram of the GH4169 powder structure used to eliminate the original particle boundaries of the present invention;

[0048] Figure 2 This is a metallographic structure diagram of a GH4169 part produced by hot isostatic pressing using GH4169 powder for eliminating original grain boundaries according to Example 1 of the present invention at a magnification of 100 μm;

[0049] Figure 3 This is a metallographic structure diagram of a GH4169 part produced by hot isostatic pressing using GH4169 powder for eliminating original grain boundaries in Example 1 of the present invention at a magnification of 50 μm;

[0050] Figure 4 This is a metallographic structure diagram of a GH4169 part prepared by hot isostatic pressing using conventional GH4169 powder (without core-shell structure) in Comparative Example 1 of the present invention at a magnification of 100 μm;

[0051] Figure 5 This is the metallographic structure diagram of a GH4169 part prepared by hot isostatic pressing using traditional GH4169 powder (without core-shell structure) in comparative example 1 of the present invention at a magnification of 50 μm.

[0052] Among them: 1 is standard GH4169 powder; 2 is transition layer alloy powder. DETAILED DESCRIPTION

[0053] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present invention. Instead, they are merely examples consistent with certain aspects of the present invention as detailed in the appended claims.

[0054] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention is described in further detail below with reference to the accompanying drawings and embodiments.

[0055] Example 1

[0056] This embodiment provides a GH4169 powder for eliminating the original particle boundaries. The GH4169 powder adopts a core-shell structure, such as Figure 1 As shown, it includes a core and a shell covering the surface of the core, the core is standard GH4169 powder 1, and the shell is transition layer alloy powder 2.

[0057] Specifically, the composition of the standard GH4169 powder 1 is as follows, by mass percentage: Cr: 18.0%, Ni: 52.0%, Nb: 5.0%, Mo: 3.0%, Ti: 0.9%, Al: 0.5%, C: 0.05%, Si: 0.5%, and the balance is Fe and unavoidable impurities; the particle size of the standard GH4169 powder 1 is 80 μm to 120 μm.

[0058] The composition of the transition layer alloy powder 2 by mass percentage is: Cr: 18.0%, Ni: 52.0%, Nb: 5.0%, Mo: 3.0%, Ti: 0.9%, Al: 0.5%, B: 0.01%, C: 0.01%, Si: 0.03%, and the remainder is Fe and unavoidable impurities (O: 0.01%, N: 0.005%, P: 0.005%, S: 0.003%, other single impurities ≤ 0.003%, total impurities ≤ 0.02%); the particle size of the transition layer alloy powder 2 is 10μm to 15μm.

[0059] This embodiment also provides a method for preparing the above-mentioned GH4169 powder, which specifically comprises the following steps:

[0060] Step 1: Prepare standard GH4169 powder 1 and transition layer alloy powder 2 using argon atomization. When preparing standard GH4169 powder 1, the atomization pressure is 7 MPa and the atomization temperature is 1550°C; when preparing transition layer alloy powder 2, the atomization pressure is 8 MPa and the atomization temperature is 1600°C.

[0061] Step 2: Place the standard GH4169 powder 1 into a fluidized bed coating device, introduce argon as a carrier gas, the argon flow rate is 15 L / min, and the feed rate of the transition layer alloy powder 2 is 0.75 g / min, that is, the ratio of the argon flow rate to the feed rate of the transition layer alloy powder 2 is 20:1. The operating temperature of the fluidized bed coating device is 100°C. The transition layer alloy powder 2 is fed into the fluidized bed coating device for a coating time of 3 hours, so that the transition layer alloy powder 2 is evenly coated on the surface of the standard GH4169 powder 1 to form a GH4169 powder with a core-shell structure.

[0062] In an embodiment of the present invention, the GH4169 powder having a core-shell structure is used to prepare a certain type of GH4169 part A for an aero-engine. The detailed preparation process is as follows:

[0063] Step 1: Place the core-shell GH4169 powder into a prefabricated stainless steel package.

[0064] Step 2: Vacuum the package until the vacuum degree is ≤4.5×10 -4 The stainless steel sheath is sealed at Pa;

[0065] Step 3: The sealed stainless steel sheath is subjected to hot isostatic pressing. The process parameters of the hot isostatic pressing are as follows: temperature of 1150°C, pressure of 120 MPa, holding time of 3 h, cooling rate of 8°C / min, and standard solution and aging heat treatment after hot isostatic pressing to obtain GH4169 part A.

[0066] Example 2

[0067] This embodiment provides a GH4169 powder for eliminating the original particle boundaries. The GH4169 powder adopts a core-shell structure, such as Figure 1 As shown, it includes a core and a shell covering the surface of the core, the core is standard GH4169 powder 1, and the shell is transition layer alloy powder 2.

[0068] Specifically, the composition of the standard GH4169 powder 1, by mass percentage, is as follows: Cr: 17.0%, Ni: 50.0%, Nb: 4.75%, Mo: 2.8%, Ti: 0.65%, Al: 0.2%, C: 0.02%, Si: 0.3%, and the balance is Fe and unavoidable impurities; the particle size of the standard GH4169 powder 1 is 50 μm to 100 μm.

[0069] The composition of the transition layer alloy powder 2 by mass percentage is: Cr: 17.0%, Ni: 50.0%, Nb: 4.75%, Mo: 2.8%, Ti: 0.65%, Al: 0.2%, B: 0.005%, C: 0.01%, Si: 0.02%, and the remainder is Fe and unavoidable impurities (O: 0.012%, N: 0.008%, P: 0.008%, S: 0.004%, other single impurities ≤ 0.004%, total impurities ≤ 0.028%); the particle size of the transition layer alloy powder 2 is 5μm to 10μm.

[0070] This embodiment also provides a method for preparing the above-mentioned GH4169 powder, which specifically comprises the following steps:

[0071] Step 1: Prepare standard GH4169 powder 1 and transition layer alloy powder 2 using argon atomization. When preparing standard GH4169 powder 1, the atomization pressure is 6 MPa and the atomization temperature is 1500°C; when preparing transition layer alloy powder 2, the atomization pressure is 7 MPa and the atomization temperature is 1550°C.

[0072] Step 2: Place the standard GH4169 powder 1 into a fluidized bed coating device, introduce argon as a carrier gas, the argon flow rate is 20 L / min, and the feed rate of the transition layer alloy powder 2 is 0.5 g / min, that is, the ratio of the argon flow rate to the feed rate of the transition layer alloy powder 2 is 40:1. The operating temperature of the fluidized bed coating device is 80°C. The transition layer alloy powder 2 is fed into the fluidized bed coating device for a coating time of 2 hours, so that the transition layer alloy powder 2 is evenly coated on the surface of the standard GH4169 powder 1 to form a GH4169 powder with a core-shell structure.

[0073] In an embodiment of the present invention, the GH4169 powder having a core-shell structure is used to prepare a certain type of GH4169 part B for an aero-engine. The detailed preparation process is as follows:

[0074] Step 1: Place the core-shell GH4169 powder into a prefabricated stainless steel package.

[0075] Step 2: Vacuum the package until the vacuum degree is ≤4×10 -4 The stainless steel sheath is sealed at Pa;

[0076] Step 3: The sealed stainless steel sheath is subjected to hot isostatic pressing. The process parameters of the hot isostatic pressing are as follows: temperature of 1100°C, pressure of 100 MPa, holding time of 2 h, cooling rate of 5°C / min, and standard solution and aging heat treatment after hot isostatic pressing to obtain GH4169 part B.

[0077] Example 3

[0078] This embodiment provides a GH4169 powder for eliminating the original particle boundaries. The GH4169 powder adopts a core-shell structure, such as Figure 1 As shown, it includes a core and a shell covering the surface of the core, the core is standard GH4169 powder 1, and the shell is transition layer alloy powder 2.

[0079] Specifically, the composition of the standard GH4169 powder 1 is as follows by mass percentage: Cr: 21.0%, Ni: 55.0%, Nb: 5.50%, Mo: 3.3%, Ti: 1.15%, Al: 0.8%, C: 0.08%, Si: 0.7%, and the balance is Fe and unavoidable impurities; the particle size of the standard GH4169 powder 1 is 100 μm to 150 μm.

[0080] The composition of the transition layer alloy powder 2 in mass percentage is: Cr: 21.0%, Ni: 55.0%, Nb: 5.50%, Mo: 3.3%, Ti: 1.15%, Al: 0.8%, B: 0.02%, C: 0.02%, Si: 0.05%, and the balance is Fe and unavoidable impurities (O: 0.015%, N: 0.01%, P: 0.01%, S: 0.005%, other single impurities ≤ 0.005%, total impurities ≤ 0.03%); the particle size of the transition layer alloy powder 2 is 10μm to 20μm.

[0081] This embodiment also provides a method for preparing the above-mentioned GH4169 powder, which specifically comprises the following steps:

[0082] Step 1: Prepare standard GH4169 powder 1 and transition layer alloy powder 2 using argon atomization. When preparing standard GH4169 powder 1, the atomization pressure is 8 MPa and the atomization temperature is 1600°C; when preparing transition layer alloy powder 2, the atomization pressure is 9 MPa and the atomization temperature is 1650°C.

[0083] Step 2: Place the standard GH4169 powder 1 into a fluidized bed coating device, introduce argon as a carrier gas, the argon flow rate is 10 L / min, and the feed rate of the transition layer alloy powder 2 is 1.0 g / min, that is, the ratio of the argon flow rate to the feed rate of the transition layer alloy powder 2 is 10:1. The operating temperature of the fluidized bed coating device is 120°C. The transition layer alloy powder 2 is fed into the fluidized bed coating device for a coating time of 4 hours, so that the transition layer alloy powder 2 is evenly coated on the surface of the standard GH4169 powder 1 to form a GH4169 powder with a core-shell structure.

[0084] In an embodiment of the present invention, the GH4169 powder having a core-shell structure is used to prepare a certain type of GH4169 part C for an aero-engine. The detailed preparation process is as follows:

[0085] Step 1: Place the core-shell GH4169 powder into a prefabricated stainless steel package.

[0086] Step 2: Vacuum the package until the vacuum degree is ≤1×10 -4 The stainless steel sheath is sealed at Pa;

[0087] Step 3: The sealed stainless steel sheath is subjected to hot isostatic pressing. The process parameters of the hot isostatic pressing are as follows: temperature of 1200°C, pressure of 150 MPa, holding time of 4 h, cooling rate of 10°C / min, and standard solution and aging heat treatment after hot isostatic pressing to obtain GH4169 part C.

[0088] Example 4

[0089] This embodiment provides a GH4169 powder for eliminating the original particle boundaries. The GH4169 powder adopts a core-shell structure, such as Figure 1 As shown, it includes a core and a shell covering the surface of the core, the core is standard GH4169 powder 1, and the shell is transition layer alloy powder 2.

[0090] Specifically, the composition of the standard GH4169 powder 1 is as follows by mass percentage: Cr: 17.0%, Ni: 55.0%, Nb: 5.50%, Mo: 2.8%, Ti: 1.15%, Al: 0.2%, C: 0.08%, Si: 0.3%, and the balance is Fe and unavoidable impurities; the particle size of the standard GH4169 powder 1 is 60 μm to 100 μm.

[0091] The composition of the transition layer alloy powder 2 in mass percentage is: Cr: 17.0%, Ni: 55.0%, Nb: 5.50%, Mo: 2.8%, Ti: 1.15%, Al: 0.2%, B: 0.005%, C: 0.02%, Si: 0.05%, and the balance is Fe and unavoidable impurities (O: 0.015%, N: 0.01%, P: 0.01%, S: 0.005%, other single impurities ≤ 0.005%, total impurities ≤ 0.03%); the particle size of the transition layer alloy powder 2 is 8μm to 15μm.

[0092] This embodiment also provides a method for preparing the GH4169 powder and a method for preparing a certain type of aircraft engine GH4169 part D based on the GH4169 powder. The preparation methods of the GH4169 powder and the preparation methods of the GH4169 part D are the same as those in Example 1 and are not described in detail here.

[0093] Comparative Example 1

[0094] This comparative example aims to produce a GH4169 part E, a specific type for aircraft engines. The specifications of this GH4169 part E are identical to those of the GH4169 part A in Example 1. The key difference between the two is that this comparative example uses traditional GH4169 powder (i.e., GH4169 powder without a core-shell structure). Furthermore, the preparation process for this comparative example is identical to that of Example 1, employing the same hot isostatic pressing process, solution treatment, and aging heat treatment.

[0095] Performance Testing

[0096] To further verify the technical effects of the present invention, the inventors conducted the following test analysis:

[0097] 1. Microstructure Observation: Metallographic analysis was performed on the GH4169 parts finally prepared in Example 1 and Comparative Example 1, and metallographic organization diagrams at two magnifications of 100 μm and 50 μm were obtained (see Figures 2 to 5 );

[0098] 2. Mechanical properties test: Mechanical properties tests were performed on the GH4169 parts prepared in Examples 1 to 4 and Comparative Example 1. The test results are shown in Table 1 below.

[0099] Table 1 Mechanical properties test results of GH4169 parts prepared in Examples 1 to 4 and Comparative Example 1

[0100]

[0101] Depend on Figure 2 、 3 It can be seen that the GH4169 parts prepared by Example 1 of the present invention using core-shell structured GH4169 powder have no obvious primary grain boundaries (PPB) in their microstructure, no continuous brittle phase distribution at the particle interface, uniform grain size, and dense and integrated metallurgical bonding characteristics, indicating that the transition layer of the core-shell structure effectively achieves the elimination of composition gradients and interface fusion. Comparative Example 1 uses traditional GH4169 powder, and the metallographic structure of the GH4169 parts formed is as follows: Figure 4 、 5 As shown in the figure, there are clearly visible primary particle boundaries (PPBs) at the particle interfaces in the metallographic structure, and continuous brittle phases such as carbides and silicides are distributed along the boundaries, which is consistent with the interface defect characteristics of traditional powders caused by composition mutations, and proves the significant effect of the core-shell structure of the present invention in eliminating PPBs.

[0102] Furthermore, the mechanical properties test results in Table 1 show that the parts made from Examples 1-4 using core-shell GH4169 powder outperformed the parts made from Comparative Example 1 using conventional GH4169 powder in all mechanical performance indicators. Specifically, the tensile strength of Examples 1-4 exceeded 1400 MPa, with Example 3 reaching 1431 MPa, while Comparative Example 1 had a tensile strength of only 1090 MPa. In terms of yield strength, Examples 1-4 were all above 1138 MPa, while Comparative Example 1 was 980 MPa, demonstrating a significant improvement in yield strength. In terms of elongation, the values ​​for Examples 1-4 ranged from 20% to 22%, while Comparative Example 1 was only 15%, demonstrating a similarly significant advantage in elongation. This improvement in mechanical properties is consistent with the results of microstructural observations. It is precisely because the gradient core-shell structure of the present invention effectively eliminates the primary particle boundaries (PPB) and interfacial brittle phases, achieving better metallurgical bonding, that the strength and plasticity of the parts are simultaneously improved, fully verifying the effectiveness of the technical solution of the present invention in improving the performance of GH4169 parts.

[0103] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present 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 present invention.

[0104] It should be understood that the present invention is not limited to the above description and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A GH4169 powder for eliminating primary particle boundaries, characterized in that: The GH4169 powder adopts a core-shell structure, comprising a core and a shell covering the surface of the core, wherein the core is standard GH4169 powder and the shell is a transition layer alloy powder; The composition of the standard GH4169 powder by mass percentage is: Cr: 17.0% to 21.0%, Ni: 50.0% to 55.0%, Nb: 4.75% to 5.50%, Mo: 2.8% to 3.3%, Ti: 0.65% to 1.15%, Al: 0.2% to 0.8%, C: 0.02% to 0.08%, Si: 0.3% to 0.7%, and the balance is Fe and unavoidable impurities; The transition layer alloy powder has the following composition by mass percentage: Cr: 17.0% to 21.0%, Ni: 50.0% to 55.0%, Nb: 4.75% to 5.50%, Mo: 2.8% to 3.3%, Ti: 0.65% to 1.15%, Al: 0.2% to 0.8%, B: 0.005% to 0.02%, C≤0.02%, Si≤0.05%, and the balance is Fe and unavoidable impurities.

2. The GH4169 powder for eliminating primary particle boundaries according to claim 1, characterized in that: The particle size of the standard GH4169 powder is 50 μm to 150 μm, and the particle size of the transition layer alloy powder is 5 μm to 20 μm.

3. The GH4169 powder for eliminating primary particle boundaries according to claim 1, characterized in that: In the transition layer alloy powder, the inevitable impurities include O≤0.015%, N≤0.01%, P≤0.01%, S≤0.005%, the remaining single impurities≤0.005%, and the total impurities≤0.03%.

4. A method for preparing the GH4169 powder according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: prepare standard GH4169 powder and transition layer alloy powder respectively; Step 2: placing the standard GH4169 powder in a fluidized bed coating device, introducing an inert gas as a carrier gas to fluidize the standard GH4169 powder; then feeding the transition layer alloy powder into the fluidized bed coating device at a preset rate, so that the transition layer alloy powder is evenly coated on the surface of the standard GH4169 powder, thereby obtaining the GH4169 powder.

5. The method for preparing GH4169 powder according to claim 4, characterized in that: In step 1, the standard GH4169 powder and the transition layer alloy powder are both prepared by argon atomization method; Wherein, when preparing the standard GH4169 powder, the atomization pressure is 6MPa-8MPa, and the atomization temperature is 1500℃-1600℃; When preparing the transition layer alloy powder, the atomization pressure is 7MPa-9MPa, and the atomization temperature is 1550°C-1650°C.

6. The method for preparing GH4169 powder according to claim 4, characterized in that: In step 2, the ratio of the flow rate of the inert gas to the feed rate of the transition layer alloy powder is (10-40):1, the operating temperature of the fluidized bed coating equipment is 80°C-120°C, and the coating time is 2h-4h.

7. The method for preparing GH4169 powder according to claim 4, characterized in that: In step 2, the flow rate of the inert gas is 10 L / min to 20 L / min, and the feed rate of the transition layer alloy powder is 0.5 g / min to 1.0 g / min.

8. A method for preparing a GH4169 product, characterized in that: The following steps are involved: Step 1: Place the GH4169 powder according to any one of claims 1 to 3 into a prefabricated package; Step 2: Vacuum the package until the vacuum degree is ≤5×10 -4 Sealing the package at Pa; Step 3: hot isostatic pressing the sealed package, and then subjecting it to standard solution treatment and aging heat treatment to obtain the GH4169 product.

9. The method for preparing the GH4169 product according to claim 8, characterized in that: In step 3, the process parameters of the hot isostatic pressing treatment are as follows: temperature of 1100° C. to 1200° C., pressure of 100 MPa to 150 MPa, holding time of 2 h to 4 h, and cooling rate of 5° C. / min to 10° C. / min.

10. A GH4169 part, characterized in that: The GH4169 part is prepared by the preparation method according to claim 8 or 9. The metallographic structure of the GH4169 part is uniform, and the mechanical properties meet the following requirements: tensile strength>1400MPa, yield strength>1130MPa, and elongation≥20%.

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