Nickel-rich high-entropy alloy composite material for extreme high-temperature environment and preparation method of nickel-rich high-entropy alloy composite material

Abstract

The invention discloses a nickel-rich high-entropy alloy composite material for an extreme high-temperature environment and a preparation method of the nickel-rich high-entropy alloy composite material, and belongs to the technical field of advanced materials and manufacturing. The preparation method comprises the following steps that S1, nickel-rich high-entropy alloy composite powder is provided, and S2, additive manufacturing is conducted through the laser powder bed melting technology, specifically, the spread nickel-rich high-entropy alloy pre-alloyed powder is scanned through a main laser beam so that the nickel-rich high-entropy alloy pre-alloyed powder can be melted and rapidly solidified, a base body blank of an endogenous dual-phase nanometer lamellar sheet interlocking structure can be formed through layer-by-layer printing, and the nickel-rich high-entropy alloy pre-alloyed powder is obtained. The method has the beneficial effects that structure-function integrated manufacturing is achieved, precise forming of a complex component, generation of an internal nanometer strengthening structure and construction of a surface authigenic anti-oxidation functional layer are synchronously completed through the double-laser synergistic additive technology, and the industrial problem of separation of manufacturing and protection is fundamentally solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of advanced materials and manufacturing technology, and particularly relates to a nickel-rich high-entropy alloy composite material for extreme high-temperature environments and a preparation method thereof. BACKGROUND

[0002] With the development of aerospace and energy industries, higher requirements are put forward for the comprehensive performance of high-temperature materials in extreme environments (such as > 1100 DEG C). The performance of traditional nickel-based high-temperature alloys is increasingly bottlenecked, and the nickel-rich high-entropy alloy exhibits great potential in high-temperature strength and microstructure stability due to the high-entropy effect and lattice distortion effect brought by its multi-principal-element characteristics, and becomes the research focus of the next generation of ultra-high-temperature materials.

[0003] However, there are still two technical bottlenecks in its engineering application: firstly, the existing casting or conventional additive manufacturing technology cannot avoid the segregation, cracks and harmful phase precipitation caused by high alloying components, and cannot simultaneously realize the accurate regulation of the nanoscale microstructure in the forming process of complex components; secondly, in the long-term ultra-high-temperature service environment, the surface oxidation film of the material is prone to peeling, and the oxidation resistance is insufficient, and the interface bonding and thermal matching of the added coating exist problems.

[0004] The purpose of the present application is to provide a nickel-rich high-entropy alloy composite material for extreme high-temperature environments and a preparation method thereof to solve the problems raised in the background art. SUMMARY

[0005] The purpose of the present application is to provide a nickel-rich high-entropy alloy composite material for extreme high-temperature environments and a preparation method thereof to solve the problems raised in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a preparation method of a nickel-rich high-entropy alloy composite material component for extreme high-temperature environments, comprising the following steps: S1, providing a nickel-rich high-entropy alloy composite powder: the composite powder is made of a nickel-rich high-entropy alloy pre-alloy powder as a matrix, and a compound containing a rare earth element is embedded on the surface of the matrix; S2, using a laser powder bed melting technology for additive manufacturing: The nickel-rich high-entropy alloy pre-alloy powder spread by the main laser beam is melted and rapidly solidified, and a matrix blank with an endogenous dual-phase nanolamellar interlocking structure is formed by layer-by-layer printing; After printing each layer, a non-melting scanning heat treatment is performed on the specific area of the current layer using an auxiliary laser beam, so as to cause the rare earth element to segregate to the surface layer and pre-oxidize, thereby forming a gradient functional layer in situ; S3, post-processing: the printed substrate blank is heat treated in a protective atmosphere or a specific oxidation atmosphere to control the precipitation of the strengthening phase in the substrate blank and stabilize the gradient functional layer, thereby obtaining the nickel-rich high-entropy alloy composite component integrated with complex internal cooling channels.

[0007] Further, the nickel-rich high-entropy alloy pre-alloy powder is mixed with a rare earth element-containing organic metal compound precursor solution, and then subjected to mechanical ball milling and subsequent drying treatment, so that the rare earth element-containing organic metal compound precursor is decomposed and uniformly adheres to the surface of the nickel-rich high-entropy alloy pre-alloy powder in the form of an oxide.

[0008] Further, the processing of the auxiliary laser beam in S2 is laser micro-fusion treatment; the process parameters of the laser micro-fusion treatment are: the power is 10%-40% of the power of the main laser beam, the spot diameter is 150%-300% of the spot diameter of the main laser beam, and the scanning speed is not less than 1000 mm / s.

[0009] Further, the process parameters of the main laser beam in S2 are: the power is 300-500 W, the scanning speed is 800-1500 mm / s, and the scanning pitch is 50-110 μm.

[0010] Further, the composition of the nickel-rich high-entropy alloy pre-alloy powder is, in atomic percentage: Ni: 25-45%, Cr: 10-20%, Co: 10-20%, Al: 2-8%, Ti: 1-5%, Ta: 1-5%, W: 1-5%, Mo: 1-5%, and inevitable trace impurities, and satisfies: the total content of Al+Ti+Ta is 5-12%.

[0011] Further, the heat treatment regime in S3 is: first, solid solution treatment at 1150-1180℃ for 1-2 hours under inert protective atmosphere; then, aging treatment at 800-850℃ for 4-8 hours under inert protective atmosphere.

[0012] Further, the component is prepared by the preparation method of any one of claims 1 to 6, has a dual-phase nano-lamella interlocking structure, and the average spacing of the nano-lamella is 20-200 nm.

[0013] Compared with the prior art, the present application has the following beneficial effects: 1. Structural-functional integrated manufacturing is achieved: through the dual-laser synergistic additive technology, the complex component precision forming, internal nano-strengthening structure generation and surface self-generated oxidation-resistant functional layer construction are completed synchronously, thereby fundamentally solving the industry problem of separation of manufacturing and protection; 2. Comprehensive performance breakthrough: The component has both nanometer lamella interlocking matrix and gradient functional surface, so that the high-temperature strength of the material is significantly improved at 1100 DEG C or above, and the oxidation resistance at 1150 DEG C is improved by more than 75%, successfully balancing the mechanical properties and environmental resistance in extreme environments. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0015] Figure 1 The working principle flowchart of the present application is shown in the figure. EMBODIMENT

[0016] In the following description, a large number of specific details are given in order to provide a more thorough understanding of the present application. However, it is obvious to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, some technical features known in the art are not described in order not to obscure the present application.

[0017] Unless the direction is defined separately, the up, down, left, right, front, back, inside and outside directions mentioned in this paper are based on the up, down, left, right, front, back, inside and outside directions in the drawings of the present application, which are explained here.

[0018] The connection mode can adopt existing modes such as bonding, welding, bolt connection, etc., according to actual needs.

[0019] As shown in the figure, according to the embodiment of the present application, a nickel-rich high-entropy alloy composite material for extreme high-temperature environment and its preparation method, comprising: Figure 1 According to the embodiment of the present application, a nickel-rich high-entropy alloy composite powder is prepared: EMBODIMENT

[0020] S1, preparation of nickel-rich high-entropy alloy composite powder: According to atomic percentage: Ni: 35%, Cr: 15%, Co: 15%, Al: 5%, Ti: 3%, Ta: 4%, W: 3%, Mo: 3%, the rest is inevitable impurities, and the pre-alloy powder is prepared by vacuum induction melting gas atomization method, and the spherical powder with particle size of 15-53 microns is selected after screening; An ethanol solution of yttrium isopropoxide with a concentration of 0.5 mol / L is prepared; 1000 g of the pre-alloyed powder and 500 mL of the yttrium isopropoxide solution were placed in a vacuum planetary ball mill, and ball milled for 2 hours at a rotation speed of 300 rpm under the protection of argon, with zirconia balls as the ball milling medium and a ball-to-powder ratio of 5:1; After ball milling, the slurry was dried in a vacuum drying oven at 80℃ for 12 hours, and then heat treated in a flowing argon atmosphere at 400℃ for 1 hour, so as to completely decompose the yttrium isopropoxide into Y2O3 and uniformly adhere to the surface of the pre-alloyed powder. Finally, a nickel-rich high-entropy alloy composite powder modified with Y2O3 on the surface was obtained, and the mass fraction of Y2O3 was about 0.8% by calculation; S2, laser powder bed fusion additive manufacturing: A self-developed dual-laser SLM device was used for printing; The main laser parameters were as follows: a 500W fiber laser was selected, the laser power was set to 400W, the scanning speed was 1200mm / s, the scanning interval was 80μm, and the powder layer thickness was 30μm. These parameters were designed to completely melt the powder and form a small molten pool through an extremely high cooling rate, so as to in-situ generate a dual-phase nanolamellar cellular structure with an FCC matrix and γ' strengthening phase; The auxiliary laser parameters were as follows: a 100W fiber laser was selected, and after the completion of the main laser scanning of each layer, the outer surface contour area of the component was immediately scanned. The auxiliary laser power was set to 80W, the main laser power was 20%, the spot diameter was 150μm, the main laser spot diameter was 250%, and the scanning speed was 1500mm / s. The energy input was calculated to be only enough to raise the surface temperature of the powder to 900-1000℃, which was not enough to cause melting, but was enough to drive the Y element to diffuse violently to the surface and cause pre-oxidation; Based on the three-dimensional model, the component was printed layer by layer, and finally a turbine blade blank integrated with a complex serpentine internal cooling channel was obtained; S3, post-processing: The printed turbine blade blank was placed in a vacuum heat treatment furnace and treated according to the following schedule: Under the protection of argon, the temperature was raised to 1160℃ at a rate of 10℃ / min, and held for 1.5 hours (solution treatment), and then the furnace was cooled to 800℃; The argon gas mixed with a small amount of oxygen (0.1% by volume fraction) was introduced, and the temperature was held at 800℃ for 6 hours, and then air-cooled to room temperature; The purpose of the solution treatment was to eliminate the printing stress, dissolve the micro-segregation, and homogenize the structure; The purpose of the aging treatment was to promote the uniform precipitation of the γ' strengthening phase in nanometer size, and to further oxidize and stabilize the Y element on the surface, forming a dense Cr2O3+Y2O3 mixed oxide gradient functional layer well combined with the matrix.

[0021] Comparative Example 1: The same pre-alloyed powder as in Example 1 was used, but without surface modification of Y2O3, and SLM printing was performed using a single main laser, with the same subsequent heat treatment regime.

[0022] Performance testing and result analysis: The samples obtained in Example 1 and Comparative Example 1 were subjected to the following tests: Microstructure characterization: metallographic and transmission electron microscopy (TEM) observations showed that the sample of Example 1 successfully formed a bi-phase nano-lamellar structure with an average lamellar spacing of about 80 nm in the interior of the sample matrix, while the sample of Comparative Example 1 also had a cell-like structure, but the lamellar spacing was uneven, and no obvious surface segregation of Y element was observed; High-temperature oxidation resistance: the samples were subjected to a 100-hour isothermal oxidation experiment in static air at 1150°C. The oxidation weight gain rate of the sample of Example 1 was reduced by about 75% compared to the sample of Comparative Example 1. The sample of Example 1 formed a continuous, dense and non-peeling oxidation film on the surface, while the oxidation film on the surface of the sample of Comparative Example 1 showed obvious cracking and peeling; High-temperature mechanical properties: high-temperature compression tests were performed at 1100°C, and the yield strength of the sample of Example 1 reached 350 MPa, with significantly better creep resistance than the sample of Comparative Example 1.

[0023] It should be noted that, in this document, relational terms such as one and another and at least one of are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying that the entities or actions are mutually exclusive or mutually inclusive. In addition, the terms "comprises", "comprising", or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without limitation, an element preceded by "comprises a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus.

[0024] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, alternatives, and variations can be made in the embodiments without departing from the spirit and scope of the present application as defined by the appended claims and their equivalents.

Claims

1. A method for preparing a nickel-rich high-entropy alloy composite component for extreme high-temperature environments, characterized in that, The method comprises the following steps: S1, providing a nickel-rich high-entropy alloy composite powder, wherein the composite powder has a nickel-rich high-entropy alloy pre-alloy powder as a matrix, and a rare earth element-containing compound is embedded on the surface of the matrix; S2, additive manufacturing by using a laser powder bed melting technology: a main laser beam is used to scan and spread the nickel-rich high-entropy alloy pre-alloy powder, so that the nickel-rich high-entropy alloy pre-alloy powder is melted and rapidly solidified, and a matrix blank with an endogenous dual-phase nano-lamellar interlocking structure is printed layer by layer; after printing each layer, a subsidiary laser beam is used to perform a non-melting scanning heat treatment on a specific area of the current layer, so as to cause the rare earth element to segregate to the surface layer and pre-oxidize, thereby forming a gradient functional layer in situ; S3, post-processing: the printed matrix blank is heat-treated in a protective atmosphere or a specific oxidation atmosphere, so as to control the precipitation of a strengthening phase in the matrix blank and stabilize the gradient functional layer, thereby obtaining the nickel-rich high-entropy alloy composite material component integrated with a complex internal cooling channel.

2. The method of claim 1, wherein the method is characterized by: The nickel-rich high-entropy alloy pre-alloy powder is provided; the nickel-rich high-entropy alloy pre-alloy powder is mixed with a rare earth element-containing organic metal compound precursor solution, and mechanical ball milling is performed; subsequently, drying treatment is performed, so that the rare earth element-containing organic metal compound precursor is decomposed and uniformly adheres to the surface of the nickel-rich high-entropy alloy pre-alloy powder in the form of an oxide.

3. The method of claim 2, wherein the method further comprises: In S2, the subsidiary laser beam is processed by laser micro-melting and solidification; and the process parameters of the laser micro-melting and solidification are as follows: the power is 10%-40% of the power of the main laser beam, the spot diameter is 150%-300% of the spot diameter of the main laser beam, and the scanning speed is not less than 1000 mm / s. ​ 4. The method of claim 3, wherein the method further comprises: In S2, the process parameters of the main laser beam are as follows: the power is 300-500 W, the scanning speed is 800-1500 mm / s, and the scanning interval is 50-110 μm. ​ 5. The method of claim 2, wherein the method further comprises: The composition of the nickel-rich high-entropy alloy pre-alloy powder, in terms of atomic percentage, is as follows: Ni: 25-45%, Cr: 10-20%, Co: 10-20%, Al: 2-8%, Ti: 1-5%, Ta: 1-5%, W: 1-5%, Mo: 1-5%, and inevitable trace impurities, and the total content of Al+Ti+Ta is 5-12%. ​ 6. The method of claim 1, wherein the method is characterized by: In S3, the heat treatment system is as follows: firstly, solid solution treatment is performed at 1150-1180 ℃ for 1-2 hours under an inert protective atmosphere; subsequently, aging treatment is performed at 800-850 ℃ for 4-8 hours under an inert protective atmosphere.

7. A nickel-rich high-entropy alloy composite component for extreme high-temperature environments, characterized by: The component is prepared by the preparation method in any one of claims 1 to 6, has a dual-phase nano-lamellar interlocking structure, and the average spacing of the nano-lamellae is 20-200 nm.

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