Preparation Method of FeMnNiCrAl Series Corrosion-Resistant High-Entropy Alloy for Reactor Structural Materials

Abstract

Embodiments of the present application relate to the technical field of metal powder processing, and particularly to a preparation method of an FeMnNiCrAl-based corrosion-resistant high-entropy alloy for reactor structural materials. The method includes the following steps: S1: Prepare high-entropy alloy powder including components of Fe, Mn, Ni, Cr, and Al; S2: Process the high-entropy alloy powder by an additive manufacturing method to obtain a high-entropy alloy; S3: Perform post-treatment on the obtained high-entropy alloy to obtain an FeMnNiCrAl-based corrosion-resistant high-entropy alloy for reactor structural materials. The preparation method provided by the embodiments of the present application can prepare an FeMnNiCrAl-based corrosion-resistant high-entropy alloy for reactor structural materials.

Description

Technical Field

[0001] Embodiments of the present application relate to the technical field of metal powder processing, and particularly to a preparation method of an FeMnNiCrAl-based corrosion-resistant high-entropy alloy for reactor structural materials. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] A high-entropy alloy is an alloy containing more than five main elements, and the concentration of each element is between 5% and 35%. When a high-entropy alloy is used in a reactor, some components in the high-entropy alloy generate strong induced radioactivity after being irradiated in the reactor, which will cause similar high-entropy alloys to be unsuitable for use in reactor internal components. In order to use high-entropy alloys to make reactor internal components, changes need to be made to them. In addition, the existing preparation methods of high-entropy alloys cannot meet the requirements for preparing reactor structures and need further improvement. Summary of the Invention

[0004] A brief overview of the present application is given below to provide a basic understanding of certain aspects of the present application. It should be understood that this overview is not an exhaustive overview of the present application. It is not intended to identify the key or important parts of the present application, nor is it intended to limit the scope of the present application. Its purpose is merely to present certain concepts in a simplified form as a prelude to the more detailed description that follows.

[0005] Embodiments of the present application provide a preparation method of an FeMnNiCrAl-based corrosion-resistant high-entropy alloy for reactor structural materials, which includes the following steps: S1: preparing high-entropy alloy powder including components of Fe, Mn, Ni, Cr, and Al; S2: processing the high-entropy alloy powder by an additive manufacturing method to obtain a high-entropy alloy; S3: performing post-treatment on the obtained high-entropy alloy to obtain an FeMnNiCrAl-based corrosion-resistant high-entropy alloy for reactor structural materials.

[0006] The preparation method provided by the embodiments of the present application uses A1 to replace Co, thus avoiding the problem that some components in the high-entropy alloy generate strong induced radioactivity after being irradiated in the reactor. Moreover, after the Al element is oxidized, a stable oxide layer can be formed on the metal surface, which is continuous and dense and can further improve the corrosion resistance of the high-entropy alloy. In addition, compared with traditional machining techniques, by using an additive manufacturing method, complex structure forming, refractory metal forming, and composition regulation can be achieved, and materials can be saved at the same time. The preparation method provided by the embodiments of the present application can prepare an FeMnNiCrAl-based corrosion-resistant high-entropy alloy more suitable for reactor structural materials. Brief Description of the Drawings

[0007] To further elaborate on the above and other advantages and features of the present application, the following provides a more detailed description of the specific embodiments of the present application with reference to the accompanying drawings. The accompanying drawings are included in this specification and form a part of this specification together with the following detailed description. Elements having the same function and structure are denoted by the same reference numerals. It should be understood that these drawings only depict typical examples of the present application and should not be regarded as limiting the scope of the present application.

[0008] Figure 1 is a schematic flowchart of steps S1 to S3 of a preparation method according to an embodiment of the present application;

[0009] Figure 2 is a schematic flowchart of steps S11 to S13 of a preparation method according to an embodiment of the present application;

[0010] Figure 3 is a schematic flowchart of steps S21 to S23 of a preparation method according to an embodiment of the present application;

[0011] Figure 4 is a schematic flowchart of steps S31 to S32 of a preparation method according to an embodiment of the present application;

[0012] Figure 5 is a surface morphology diagram of a high-entropy alloy prepared according to an embodiment of the present application;

[0013] Figure 6 is a surface morphology diagram of a high-entropy alloy prepared according to another embodiment of the present application.

[0014] It should be noted that the accompanying drawings are not necessarily drawn to scale, but are only shown in a schematic manner that does not affect the reader's understanding. Detailed Description of Specific Embodiments

[0015] In the following, exemplary embodiments of the present application will be described with reference to the accompanying drawings. For clarity and conciseness, not all features of the actual embodiments are described in the specification. However, it should be understood that many implementation-specific decisions must be made during the development of any such actual embodiment in order to achieve the developer's specific goals, for example, to comply with those system- and business-related constraints, and such constraints may vary with different embodiments. In addition, it should be understood that although the development work may be very complex and time-consuming, for those skilled in the art who benefit from the content of the present application, such development work is merely a routine task.

[0016] Here, it should also be noted that in order to avoid obscuring the present application due to unnecessary details, only the device structures and / or processing steps closely related to the solution according to the present application are shown in the drawings, while other details less related to the present application are omitted.

[0017] The following disclosure provides multiple different embodiments or examples for implementing the present application. To simplify the disclosure of the present application, the components and methods of specific examples are described below. Of course, they are only examples and are not intended to limit the present application. In the description of the embodiments of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0018] See Figure 1 , the embodiments of the present application provide a preparation method for a FeMnNiCrAl-based corrosion-resistant high-entropy alloy for reactor structural materials, which includes the following steps S1 to S3:

[0019] S1: Prepare high-entropy alloy powder including components of Fe, Mn, Ni, Cr, and Al.

[0020] S2: Process the high-entropy alloy powder by additive manufacturing to obtain a high-entropy alloy.

[0021] S3: Post-process the obtained high-entropy alloy to obtain a FeMnNiCrAl-based corrosion-resistant high-entropy alloy for reactor structural materials.

[0022] Using A1 to replace Co avoids the problem of strong induced radioactivity generated after some components in the high-entropy alloy are irradiated in the reactor. Moreover, after the Al element is oxidized, a stable oxide layer can be formed on the metal surface, which is continuous and dense and can further improve the corrosion resistance of the high-entropy alloy; in addition, compared with traditional machining techniques, by using additive manufacturing methods, complex structure forming, refractory metal forming, and composition regulation can be achieved, and at the same time, materials can be saved. The preparation method provided by the embodiments of the present application can prepare a FeMnNiCrAl-based corrosion-resistant high-entropy alloy more suitable for reactor structural materials.

[0023] Additive manufacturing is commonly known as 3D printing. In additive manufacturing technology, according to the designed three-dimensional model, a three-dimensional object is processed layer by layer. In the embodiments of the present application, the selective laser melting method in additive manufacturing is used to form the high-entropy alloy powder. Thus, the use of a binder can be avoided, and the forming accuracy and mechanical properties of the high-entropy alloy are significantly improved.

[0024] See Figure 2 , in some embodiments, in step S1, the following steps S11 to S13 are further included:

[0025] S11: Mix raw materials including Fe, Mn, Ni, Cr, and Al components according to a predetermined ratio.

[0026] S12: Vacuum melt the mixture obtained in step S11.

[0027] S13: Treat the product obtained in step S12 by gas atomization to obtain powder.

[0028] The particle size distribution of the powder obtained through the above steps can be between 15 - 53 μm. Such particle size of the powder is beneficial for subsequent additive manufacturing to improve the properties of the alloy obtained by additive manufacturing.

[0029] In some embodiments, the elemental contents of the powder obtained in step S13 are: Fe: 10% - 30%, Mn: 10% - 30%, Ni: 10% - 30%, Cr: 10% - 30%, Al: 5% - 30%.

[0030] For example, in step S11, after mixing Fe, Mn, Ni, Cr, and Al in equal proportions, vacuum melt them, and treat the product of vacuum melting by gas atomization. The elemental contents of the obtained powder are: Fe: 20%, Mn: 20%, Ni: 20%, Cr: 20%, Al: 20%.

[0031] See Figure 3 , in some embodiments, in step S2, the following steps S21 to S22 are further included:

[0032] S21: Set parameters for the system used for additive manufacturing.

[0033] S22: Place the high-entropy alloy powder into the system for additive manufacturing for processing.

[0034] The inventors of the present application found that during the additive manufacturing process, the obtained high-entropy alloy may generate macroscopic defects and microscopic defects, such as unfrozen particles and voids, resulting in density loss. By setting parameters for the system for additive manufacturing, the defects inside the high-entropy alloy can be reduced, and the density loss of preparing the high-entropy alloy can be avoided.

[0035] In some embodiments, before step S21, the system for additive manufacturing can be cleaned first, for example, using a dust suction device to remove the powder and dust inside the system, and using alcohol to wipe the inside of the system to ensure the cleanliness inside the system during the additive manufacturing process.

[0036] In some embodiments, in step S21, for example, the system parameters of additive manufacturing can be set within the following ranges: the laser power is 80 W to 300 W, the scanning speed is 400 mm / s to 1300 mm / s, the scanning spacing is 0.04 mm to 0.08 mm, the powder spreading layer thickness is 0.02 mm to 0.06 mm, and the scanning mode is integral spiral 67°.

[0037] In some embodiments, the laser power is 250 W, the scanning speed is 1300 mm / s, the scanning spacing is 0.07 mm, the powder spreading layer thickness is 0.03 mm, and the scanning mode is integral spiral 67°. Figure 5 FIG. is a surface morphology diagram of the high-entropy alloy obtained using the parameters of this embodiment. In this embodiment, the high-entropy alloy has a dense surface.

[0038] In some other embodiments, the laser power is 150 W, the scanning speed is 600 mm / s, the scanning spacing is 0.07 mm, the powder spreading layer thickness is 0.03 mm, and the scanning mode is integral spiral 67°. Figure 6 FIG. is a surface morphology diagram of the high-entropy alloy obtained using the parameters of this embodiment. In this embodiment, the high-entropy alloy has a dense surface.

[0039] In some embodiments, in step S22, the specific processing operations include putting the FeMnNiCrAl-based high-entropy alloy powder into the powder cylinder of the additive manufacturing system, adjusting the height of the powder platform so that the powder is flush with the upper edge of the powder cylinder. Place a clean stainless steel substrate on the forming platform, adjust the substrate to be horizontal, and the upper surface height of the substrate is flush with the upper edge of the powder bed. After the above processing is completed, close the hatch of the additive manufacturing system, start the additive manufacturing system, and melt the alloy powder layer by layer on the substrate.

[0040] After all the alloy powder on the substrate is melted, the substrate and the alloy are separated by wire cutting to obtain the FeMnNiCrAl-based high-entropy alloy.

[0041] In some embodiments, in step S2, it further includes step S23: input a protective atmosphere into the additive manufacturing system and make the oxygen content in the additive manufacturing system zero. The protective atmosphere can be argon, for example. By inputting a protective atmosphere into the system, it is possible to prevent the metal from being oxidized during the additive manufacturing process.

[0042] See Figure 4 , in some embodiments, step S3 further includes the following steps S31 to step S32:

[0043] S31: Perform vacuum annealing treatment on the obtained high-entropy alloy.

[0044] S32: Perform hot isostatic pressing treatment on the high-entropy alloy processed in step S31.

[0045] By subjecting the high-entropy alloy to vacuum annealing treatment and hot isostatic pressing treatment, the metal defects inside the high-entropy alloy can be effectively reduced, and the density of the high-entropy alloy can be increased.

[0046] In some embodiments, in step S31, the temperature for the annealing heat treatment is 900 - 1200 °C, the heating rate is 10 °C / min, and when the temperature is raised to the predetermined temperature, it is held for 0 - 2 hours; after the above treatment, the high-entropy alloy is cooled to room temperature. The high-entropy alloy obtained within the above control parameter range has the fewest metal defects inside.

[0047] In some embodiments, in step S32, the temperature during the hot isostatic pressing treatment is 1100 °C - 1300 °C, the pressure is 90 MPa - 180 MPa, and it is held under pressure for 0 - 4 hours. After the above treatment, the high-entropy alloy is cooled to room temperature. The high-entropy alloy obtained within the above control parameter range has the fewest metal defects inside.

[0048] The following details the preparation of the Figure 5 high-entropy alloy shown using the preparation method provided by the present invention.

[0049] Prepare high-entropy alloy powder including components of Fe, Mn, Ni, Cr, and Al: Mix the raw materials including components of Fe, Mn, Ni, Cr, and Al according to a predetermined ratio; subject the obtained mixture to vacuum melting; subject the obtained product to gas atomization treatment to obtain powder, and the powder particle size distribution is 15 - 53 μm. The above predetermined ratio is Fe: 20%, Mn: 20%, Ni: 20%, Cr: 20%, Al: 20%.

[0050] Use the additive manufacturing method to process the high-entropy alloy powder to obtain a high-entropy alloy:

[0051] Use a dust suction device to clean the original powder, dust, and impurities inside the additive manufacturing system. Wipe the inside of the additive manufacturing system with alcohol to make the system environment clean.

[0052] According to the shape of the high-entropy alloy structure to be prepared as expected, draw the drawings for use by the additive manufacturing system. For example, the expected shape to be prepared is a 10 mm * 10 mm * 10 mm cube. Set the parameters for the additive manufacturing system: the laser power is 250 W, the scanning speed is 1300 mm / s, the scanning spacing is 0.07 mm, the powder spreading layer thickness is 0.03 mm, and the scanning method is a global spiral of 67°.

[0053] Put the FeMnNiCrAl high-entropy alloy powder into the powder cylinder of the additive manufacturing system. Adjust the height of the powder platform of the additive manufacturing system so that the powder is flush with the upper edge of the powder cylinder. Place a clean stainless steel substrate on the forming platform of the additive manufacturing system, and adjust the stainless steel substrate to be horizontal and the height of its upper surface to be flush with the upper edge of the powder bed of the additive manufacturing system. After the adjustment, close the hatch of the additive manufacturing system. Start the vacuum pump and introduce a protective atmosphere, such as argon, into the additive manufacturing system until the oxygen content in the system is 0. Start the additive manufacturing system and melt and deposit the alloy powder layer by layer on the clean stainless steel substrate to prepare the FeMnNiCrAl high-entropy alloy. After printing is completed, separate the substrate from the alloy by wire cutting to obtain the FeMnNiCrAl high-entropy alloy.

[0054] Perform post-treatment on the obtained high-entropy alloy to obtain the corrosion-resistant FeMnNiCrAl high-entropy alloy for reactor structural materials.

[0055] The following details the preparation of the Figure 6 high-entropy alloy shown using the preparation method provided by the present invention.

[0056] Prepare a high-entropy alloy powder including Fe, Mn, Ni, Cr, and Al components: Mix the raw materials including Fe, Mn, Ni, Cr, and Al components according to a predetermined ratio; perform vacuum melting on the obtained mixture; perform gas atomization treatment on the obtained product to obtain powder, and the particle size distribution of the powder is 15 - 53 μm. The above-mentioned predetermined ratio is Fe: 20%, Mn: 20%, Ni: 20%, Cr: 20%, Al: 20%.

[0057] Use the additive manufacturing method to process the high-entropy alloy powder to obtain a high-entropy alloy:

[0058] Use a dust suction device to clean the original powder, dust, and impurities in the additive manufacturing system. Wipe the inside of the additive manufacturing system with alcohol to make the environment of the system clean.

[0059] According to the shape of the high-entropy alloy structure to be prepared, draw drawings for use in the additive manufacturing system. For example, the expected shape to be prepared is a 10 mm * 10 mm * 10 mm cube. Set the parameters for the additive manufacturing system: the laser power is 150 W, the scanning speed is 600 mm / s, the scanning spacing is 0.07 mm, the powder spreading layer thickness is 0.03 mm, and the scanning method is overall spiral 67°.

[0060] Put the FeMnNiCrAl high-entropy alloy powder into the powder cylinder of the additive manufacturing system. Adjust the height of the powder platform of the additive manufacturing system until the powder is flush with the upper edge of the powder cylinder. Place a clean stainless steel substrate on the forming platform of the additive manufacturing system, and adjust the stainless steel substrate to be horizontal and the height of its upper surface to be flush with the upper edge of the powder bed of the additive manufacturing system. After the adjustment, close the hatch of the additive manufacturing system. Start the vacuum pump and introduce a protective atmosphere, such as argon, into the additive manufacturing system until the oxygen content in the system is 0. Start the additive manufacturing system and melt and deposit the alloy powder layer by layer on the clean stainless steel substrate to prepare the FeMnNiCrAl high-entropy alloy. After printing is completed, separate the substrate from the alloy by wire cutting to obtain the FeMnNiCrAl high-entropy alloy.

[0061] Perform post-treatment on the obtained high-entropy alloy to obtain the FeMnNiCrAl corrosion-resistant high-entropy alloy for the reactor structural material.

[0062] For the embodiments of the present application, it should also be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other to obtain new embodiments.

[0063] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. The protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A preparation method of an FeMnNiCrAl-based corrosion-resistant high-entropy alloy for reactor structural materials, characterized in that, It includes the following steps: S1: Prepare a high-entropy alloy powder composed of Fe, Mn, Ni, Cr, and Al. S2: Use an additive manufacturing method to process the high-entropy alloy powder to obtain the high-entropy alloy. S3: Post-process the obtained high-entropy alloy to obtain the corrosion-resistant high-entropy alloy of the FeMnNiCrAl system for reactor structural materials. In step S1, it further includes: S11: Mix the raw materials composed of Fe, Mn, Ni, Cr, and Al according to a predetermined ratio. S12: Vacuum melt the mixture obtained in step S11. S13: Process the product obtained in step S12 by gas atomization so that the particle size of the obtained powder is distributed between 15 - 53 μm. The elemental contents of the powder obtained in step S13 are: Fe: 10% - 30%, Mn: 10% - 30%, Ni: 10% - 30%, Cr: 10% - 30%, Al: 5% - 30%. Step S3 further includes the steps: S31: Perform vacuum annealing treatment on the obtained high-entropy alloy. S32: Perform hot isostatic pressing treatment on the high-entropy alloy after the treatment in step S31. In step S32, when performing hot isostatic pressing treatment, the temperature is 1100°C - 1300°C, the pressure is 90 MPa - 180 MPa, keep the temperature and pressure for 0 - 4 hours, and after the above treatment, cool the high-entropy alloy to room temperature. In step S2, it further includes the following steps: S21: Set parameters for the additive manufacturing system. S22: Place the high-entropy alloy powder into the additive manufacturing system for processing. In step S21, The laser power is 80 W - 300 W, the scanning speed is 400 mm / s - 1300 mm / s, the scanning spacing is 0.04 mm - 0.08 mm, the powder spreading layer thickness is 0.02 mm - 0.06 mm, and the scanning mode is overall spiral 67°.

2. The method according to claim 1, wherein It further includes the step: S23: Input a protective atmosphere into the additive manufacturing system and make the oxygen content in the additive manufacturing system 0.

3. The method according to claim 1, wherein In step S31, the temperature for annealing heat treatment is 900 - 1200°C, the heating rate is 10°C / min, and when heating to the predetermined temperature, keep the temperature for 0 - 2 hours; after the above treatment, cool the high-entropy alloy to room temperature.

4. The method according to claim 1, wherein After the high-entropy alloy powder is placed into the additive manufacturing system for processing and completed, use wire cutting to separate the substrate from the obtained high-entropy alloy.

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