A method for preparing a nickel-based superalloy powder for a molten salt reactor, a method for preparing a nickel-based superalloy component, and applications
Nickel-based high-temperature alloy powders were prepared by vacuum induction melting, rotating electrode atomization, and hot isostatic pressing, which solved the problem of insufficient corrosion resistance and radiation resistance of existing alloys in molten salt reactors. This enabled the preparation of high-performance parts and improved the safety and lifespan of key components in molten salt reactors.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SINO EURO MATERIALS TECH OF XIAN CO LTD
- Filing Date
- 2026-01-30
- Publication Date
- 2026-06-12
AI Technical Summary
Existing nickel-based superalloys have problems such as insufficient resistance to molten salt corrosion, insufficient resistance to radiation, and uneven distribution of dispersed strengthening phases in molten salt reactors. These problems lead to defects such as porosity and inclusions inside alloy powder metallurgy parts, affecting the service safety of the parts.
Nickel-based high-temperature alloy powders were prepared by combining vacuum induction melting and vacuum consumable melting with rotating electrode atomization powder preparation. High-performance molten salt stack parts were then prepared by hot isostatic pressing (HIP) technology. Y2O3 particles were added to ensure uniform dispersion. Combined with strict control of impurity content and composition design, near-net-shape forming technology of powder HIP was used.
The prepared alloy powder has high purity and density, and the parts have uniform structure. It has excellent resistance to molten salt corrosion and radiation, which significantly improves the service safety and service life of key components of molten salt reactors.
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Figure CN122184376A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of high-temperature alloy materials technology, and relates to a method for preparing nickel-based high-temperature alloy powder for molten salt reactors, a method for preparing nickel-based high-temperature alloy components, and their applications. Background Technology
[0002] As an important type of fourth-generation advanced nuclear reactor, molten salt reactors are characterized by extreme operating conditions such as high temperature, high radiation, and highly corrosive molten salt (such as fluoride molten salt). This places stringent requirements on the high temperature resistance (long-term service temperature needs to reach 700-850℃), molten salt corrosion resistance, radiation swelling resistance, and mechanical stability of the core structural materials.
[0003] Currently, commonly used structural materials for molten salt reactors mainly include traditional nickel-based alloys such as Hastelloy N alloy and Inconel 625 alloy. However, these alloys suffer from insufficient resistance to molten salt corrosion and radiation during long-term service, as well as uneven distribution of dispersed strengthening phases leading to unsatisfactory performance improvements. Furthermore, alloy powders prepared using existing technologies are prone to issues such as hollow powder, satellite spheres, or compositional segregation, resulting in defects such as porosity and inclusions within powder metallurgy parts, or poor consistency in microstructure and properties, thus affecting the service safety of the parts.
[0004] Therefore, there is an urgent need to develop a method for preparing nickel-based superalloy powder, as well as a corresponding high-efficiency powder hot isostatic pressing process for preparing nickel-based superalloy components. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of the prior art and to propose a method for preparing nickel-based superalloy powder for molten salt reactors, a method for preparing nickel-based superalloy components, and their applications.
[0006] In a first aspect, this invention discloses a method for preparing nickel-based high-temperature alloy powder for molten salt reactors, such as... Figure 1 As shown, it includes the following steps: Step 1: Weigh the raw materials according to the ingredient requirements. The raw materials include Ni blocks, Cr blocks, Mo flakes, Fe-C master alloy and Y2O3 particles, and pre-treat the raw materials. Step 2: The pretreated raw materials are subjected to vacuum induction melting and vacuum arc remelting in sequence to obtain preformed bars; Step 3: First, degas the preformed rods, then perform rotary electrode atomization to produce powder, and finally obtain nickel-based high-temperature alloy powder after sieving and impurity removal.
[0007] Furthermore, in step one, the pretreatment of the raw materials involves first ultrasonically cleaning the raw materials, and then drying them in a vacuum drying oven at 120°C for 2 hours.
[0008] Furthermore, in step two, vacuum induction melting involves introducing Ar gas into a vacuum induction melting furnace with a vacuum degree ≤ 5×10⁻³Pa until the furnace pressure reaches 0.1-0.12MPa, then heating to 1550-1600℃ at a heating rate of 5-8℃ / min, holding at that temperature for 30-40min, and stirring during the heating process to complete vacuum induction melting; the vacuum degree in vacuum self-consumable melting is ≤ 5×10⁻³Pa, and the power is 100-200kW.
[0009] Furthermore, in step two, the ingot obtained by vacuum induction melting is subjected to vacuum self-consumption melting again, with a vacuum degree ≤5×10⁻³Pa and a power of 100-200kW.
[0010] Furthermore, in step three, the precast bars are degassed by placing them in a feeding hopper with integrated heating and degassing functions for high-temperature degassing, followed by cooling.
[0011] Further, in step three, the chemical composition of the nickel-based superalloy powder, by mass percentage, is as follows: Cr: 5.8-8.5%, Mo: 14.4-18.3%, C: 0.02-0.1%, Fe: 2.8–4.8%, Y: 0.05-0.3%, Mn≤1%, Si≤1%, Co≤0.02%, Cu≤0.1%, Ti≤0.1%, Al≤0.1%, B≤0.005%, P≤0.005%, S≤0.005%, O≤0.01%, N≤0.01%, B≤0.001%, with the balance being Ni.
[0012] Secondly, this invention also discloses a method for preparing high-performance molten salt reactor components, wherein the high-performance molten salt reactor components are prepared from powder produced by the above-described method, such as... Figure 2 As shown, it includes the following steps: Step 1: Make a sleeve according to the shape of the part and polish the inner wall of the sleeve, and then perform vacuum heat treatment on the sleeve; Step 2: Load the nickel-based high-temperature alloy powder into the cladding, then degas the cladding, and seal the degassing hole after degassing; Step 3: After hot isostatic pressing, remove the sealed cladding to obtain nickel-based high-temperature alloy components for molten salt reactors.
[0013] Furthermore, in step one, the vacuum heat treatment of the casing is carried out at 200-450℃ for 1-5 hours.
[0014] Furthermore, in step two, the casing is degassed at 400-500℃ for 4-12 hours until the internal gas pressure of the casing is ≤1×10-4Pa.
[0015] Furthermore, in step three, the sealed casing is subjected to hot isostatic pressing at 1100-1260℃ and 120-150MPa for 3-5 hours, followed by cooling to room temperature at a cooling rate of 15℃ / min to 25℃ / min.
[0016] Furthermore, in step three, the density of the nickel-based high-temperature alloy component for the molten salt stack is ≥99.8%, the tensile strength at room temperature is ≥1100MPa, and the yield strength is ≥1000MPa.
[0017] Thirdly, this invention discloses the application of nickel-based high-temperature alloy components for molten salt reactors prepared by a method for preparing high-performance molten salt reactor components in …
[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. Optimized composition design: By rationally combining anti-corrosion elements Cr and Mo and strengthening elements Fe and C, strictly controlling the impurity content, and appropriately dispersing Y2O3, the alloy powder has excellent resistance to molten salt corrosion, high temperature strength and radiation resistance, which can meet the long-term service requirements of molten salt reactors at 700-850℃. 2. Excellent powder quality: The plasma rotating electrode atomization powder preparation process is adopted, and the rods used for powder preparation are pretreated by vacuum purification. Combined with atmosphere-protected powder classification and shaping, the prepared alloy powder has high purity, few inclusions, low hollow powder rate and good sphericity, which lays the foundation for high metallurgical quality of hot isostatic pressing parts. 3. Process advantages: The powder hot isostatic pressing near-net-shape forming technology overcomes the segregation and anisotropy problems of traditional casting and forging processes, and can obtain near-net-shape parts with extremely uniform and fully dense microstructure. The material utilization rate is high, and it is especially suitable for preparing complex-shaped core components. When adding Y2O3 particles during melting, the Y2O3 particles generated in situ by adding Y element are more uniformly dispersed than those generated in situ by adding Y element, which significantly improves the performance. 4. Stable component performance: The prepared hot isostatic pressed components have high density (≥99.8%), uniform microstructure, and excellent mechanical properties. They also exhibit extremely low corrosion rates and excellent radiation resistance in fluoride molten salts, which can significantly improve the service safety and service life of key components in molten salt reactors. Attached Figure Description
[0019] 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.
[0020] 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, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the process for preparing nickel-based superalloy powder for molten salt reactors in this invention; Figure 2 This is a schematic diagram of the process for preparing high-performance molten salt reactor components in this invention; Figure 3 Metallographic diagram of the high-performance molten salt reactor component prepared in Example 1; Figure 4 Metallographic diagram of the high-performance molten salt reactor component prepared in Example 2; Figure 5 The image shows the metallographic structure of the high-performance molten salt reactor component prepared in Example 3. Detailed Implementation
[0022] 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.
[0023] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.
[0024] Preparation Example 1 This preparation example provides a method for preparing nickel-based superalloy powder for molten salt reactors, such as... Figure 1 As shown, it includes the following steps: Step 1: Weigh the raw materials according to the ingredient requirements. The raw materials include Ni blocks, Cr blocks, Mo flakes, Fe-C master alloy and Y2O3 particles, and pre-treat the raw materials. Specifically, according to the ingredient requirements, weigh out pure Ni blocks (purity ≥99.95%), Cr blocks (purity ≥99.9%), Mo flakes (purity ≥99.9%), Fe-C master alloy, and Y2O3 particles. Perform ultrasonic cleaning on the raw materials (using anhydrous ethanol as the cleaning agent) to remove surface oil and oxide scale, and then dry them in a vacuum drying oven at 120℃ for 2 hours. The chemical composition of the raw material, by mass percentage, is as follows: Cr: 5.9%, Mo: 18.0%, C: 0.03%, Fe: 2.9%, Y: 0.06%, Mn≤1%, Si≤1%, Co≤0.02%, Cu≤0.1%, Ti≤0.1%, Al≤0.1%, B≤0.005%, P≤0.005%, S≤0.005%, O≤0.01%, N≤0.01%, B≤0.001%, with the balance being Ni; Step 2: The pretreated raw materials are subjected to vacuum induction melting and vacuum arc remelting in sequence to obtain preformed bars; Specifically, the pretreated raw materials are added to an alumina crucible, placed in a vacuum induction melting furnace, the furnace door is closed, and a vacuum is drawn to a furnace vacuum degree of 4.8×10⁻³Pa. Then, Ar gas with a purity ≥99.999% is introduced until the furnace pressure is 0.10MPa. The induction power supply is turned on, and the temperature is raised to 1555℃ at a heating rate of 5℃ / min and held for 40min to completely melt and homogenize the raw materials. During this process, electromagnetic stirring (stirring frequency 50-60Hz) is used to eliminate component segregation. After vacuum induction melting, a second vacuum consumable melting is performed (vacuuming to a furnace vacuum degree of 4.8×10⁻³Pa, power 110kW) to further improve the alloy homogeneity.
[0025] The alloy is machined to obtain rods for powder making.
[0026] Step 3: First, degas the preformed rods, then perform rotary electrode atomization to produce powder, and finally obtain nickel-based high-temperature alloy powder after sieving and impurity removal.
[0027] Specifically, the rods are placed in a feeding chamber with integrated heating and degassing functions for high-temperature degassing to remove water and oxygen impurities adsorbed by the rods. After cooling, the rods are directly fed from the feeding chamber to the transmission chamber for atomization and powder production by rotating electrodes.
[0028] The powder was then sieved to remove impurities. The collected powder was sieved under atmospheric protection to remove fine powder with a particle size of less than 53 μm and coarse powder with a particle size of more than 150 μm. Magnetic impurities in the powder were removed by magnetic separation device, and non-metallic impurities in the powder were removed by electrostatic separation device. Finally, it was vacuum packaged to obtain the high-purity nickel-based high-temperature alloy powder with a sphericity of 99.5% and a hollow powder rate of 0.3%.
[0029] Example 1 This embodiment provides a method for preparing a nickel-based superalloy component (the nickel-based superalloy powder used in this embodiment is prepared from Preparation Example 1), and the specific steps are as follows: Step 1: Make a sleeve according to the shape of the part and polish the inner wall of the sleeve, and then perform vacuum heat treatment on the sleeve; Specifically, a cylindrical stainless steel sheath is designed and manufactured. The inner wall of the sheath is polished (roughness Ra is 1.2μm) to remove surface oxide scale and oil stains. Then, the sheath is subjected to vacuum heat treatment (220℃, 5h) to remove any residual air and moisture in the material. Step 2: Load the nickel-based high-temperature alloy powder into the cladding, then degas the cladding, and seal the degassing hole after degassing; Specifically, nickel-based superalloy powder is loaded into a casing. During the loading process, heating and vibration are performed to allow air and moisture adsorbed on the surface of the powder particles to escape fully, resulting in a powder filling density of 68%. After loading, degassing is performed at 410℃ for 12 hours, with an internal pressure of 9.7×10⁻⁵ Pa, thereby removing air and adsorbed gases from the casing. After degassing, the degassing holes are sealed with lead seal welding to ensure the airtightness of the casing. Step 3: After hot isostatic pressing, remove the sealed cladding to obtain nickel-based high-temperature alloy components for molten salt reactors.
[0030] Specifically, the sealed cladding is placed in a hot isostatic pressing furnace and held at 1120℃ and 148Pa for 5 hours to completely densify the powder. Then, it is rapidly cooled to room temperature at a cooling rate of 15℃ / min, simultaneously achieving powder densification and high-pressure solution heat treatment. Next, the cladding is removed by machining to obtain a nickel-based superalloy component for molten salt reactors. This component has a density of 99.9%, a uniform microstructure, a room temperature tensile strength of 1123 MPa, a yield strength of 1011 MPa, and exhibits excellent radiation resistance and corrosion resistance.
[0031] Preparation Example 2 This preparation example provides a method for preparing nickel-based superalloy powder for molten salt reactors, including the following steps: Step 1: Weigh the raw materials according to the ingredient requirements. The raw materials include Ni blocks, Cr blocks, Mo flakes, Fe-C master alloy and Y2O3 particles, and pre-treat the raw materials. Specifically, according to the ingredient requirements, weigh out pure Ni blocks (purity ≥99.95%), Cr blocks (purity ≥99.9%), Mo flakes (purity ≥99.9%), Fe-C master alloy, and Y2O3 particles. Perform ultrasonic cleaning on the raw materials (using anhydrous ethanol as the cleaning agent) to remove surface oil and oxide scale, and then dry them in a vacuum drying oven at 120℃ for 2 hours. The specific composition of the ingredients is as follows: Cr: 7.1%, Mo: 16.4%, C: 0.06%, Fe: 3.8%, Y: 0.18%, Mn≤1%, Si≤1%, Co≤0.02%, Cu≤0.1%, Ti≤0.1%, Al≤0.1%, B≤0.005%, P≤0.005%, S≤0.005%, O≤0.01%, N≤0.01%, B≤0.001%, with the balance being Ni.
[0032] Step 2: The pretreated raw materials are subjected to vacuum induction melting and vacuum arc remelting in sequence to obtain preformed bars; Specifically, the pretreated raw materials are added to an alumina crucible, placed in a vacuum induction melting furnace, the furnace door is closed, and a vacuum of 4.9 × 10⁻³ Pa is drawn into the furnace. Then, Ar gas with a purity ≥ 99.999% is introduced into the furnace at a pressure of 0.11 MPa. The induction power supply is turned on, and the furnace is heated to 1575℃ at a heating rate of 6℃ / min and held for 35 minutes to completely melt and homogenize the raw materials. During this process, electromagnetic stirring (stirring frequency 55Hz) is performed to eliminate component segregation. After vacuum induction melting, a second vacuum consumable melting is performed (the furnace is drawn into a vacuum of 4.9 × 10⁻³ Pa, power 190kW) to further improve the alloy uniformity.
[0033] The alloy is machined to obtain rods for powder making.
[0034] Step 3: First, degas the preformed rods, then perform rotary electrode atomization to produce powder, and finally obtain nickel-based high-temperature alloy powder after sieving and impurity removal.
[0035] Specifically, the rods are placed in a feeding chamber with integrated heating and degassing functions for high-temperature degassing to remove water and oxygen impurities adsorbed by the rods. After cooling, the rods are directly fed from the feeding chamber to the transmission chamber for atomization and powder production by rotating electrodes.
[0036] The powder was then sieved to remove impurities. The collected powder was sieved under atmospheric protection to remove fine powder with a particle size of less than 53 μm and coarse powder with a particle size of more than 150 μm. Magnetic impurities in the powder were removed by magnetic separation device, and non-metallic impurities in the powder were removed by electrostatic separation device. Finally, it was vacuum packaged to obtain the high-purity nickel-based high-temperature alloy powder with a sphericity of 99.5% and a hollow powder rate of 0.3%.
[0037] Example 2 This embodiment provides a method for preparing a nickel-based superalloy component (the nickel-based superalloy powder used in this embodiment is prepared from Preparation Example 2), and the specific steps are as follows: Step 1: Make a sleeve according to the shape of the part and polish the inner wall of the sleeve, and then perform vacuum heat treatment on the sleeve; Specifically, a cylindrical stainless steel sheath is designed and manufactured. The inner wall of the sheath is polished (roughness Ra is 0.8μm) to remove surface oxide scale and oil stains. Then, the sheath is subjected to vacuum heat treatment (320℃, 3.5h) to remove any residual air and moisture in the material. Step 2: Load the nickel-based high-temperature alloy powder into the cladding, then degas the cladding, and seal the degassing hole after degassing; Specifically, nickel-based superalloy powder was loaded into a cladding. Heating and vibration were performed during the loading process to allow air and moisture adsorbed on the powder particles to escape fully, resulting in a powder filling density of 67%. After loading, degassing was performed at 450℃ for 8 hours, achieving an internal pressure of 9.7 × 10⁻⁶. -5 Pa, thereby removing air and gas adsorbed by powder inside the casing; after degassing, the degassing hole is sealed by lead seal welding to ensure the airtightness of the casing; Step 3: After hot isostatic pressing, remove the sealed cladding to obtain nickel-based high-temperature alloy components for molten salt reactors.
[0038] Specifically, the sealed cladding is placed in a hot isostatic pressing furnace and held at 1190℃ and 135MPa for 4 hours to completely densify the powder. Then, it is rapidly cooled to room temperature at a cooling rate of 20℃ / min, simultaneously achieving powder densification and high-pressure solution heat treatment. Next, the cladding is removed by machining to obtain a nickel-based superalloy component for molten salt reactors. This component has a density of 99.9%, a uniform microstructure, a room temperature tensile strength ≥1133MPa, a yield strength ≥1021MPa, and exhibits excellent radiation resistance and corrosion resistance.
[0039] Preparation Example 3 This preparation example provides a method for preparing nickel-based superalloy powder for molten salt reactors, including the following steps: Step 1: Weigh the raw materials according to the ingredient requirements. The raw materials include Ni blocks, Cr blocks, Mo flakes, Fe-C master alloy and Y2O3 particles, and pre-treat the raw materials. Specifically, according to the ingredient requirements, weigh out pure Ni blocks (purity ≥99.95%), Cr blocks (purity ≥99.9%), Mo flakes (purity ≥99.9%), Fe-C master alloy, and Y2O3 particles. Perform ultrasonic cleaning on the raw materials (using anhydrous ethanol as the cleaning agent) to remove surface oil and oxide scale, and then dry them in a vacuum drying oven at 120℃ for 2 hours. The specific composition of the ingredients is as follows: Cr: 8.3%, Mo: 14.7%, C: 0.09%, Fe: 4.6%, Y: 0.28%, Mn≤1%, Si≤1%, Co≤0.02%, Cu≤0.1%, Ti≤0.1%, Al≤0.1%, B≤0.005%, P≤0.005%, S≤0.005%, O≤0.01%, N≤0.01%, B≤0.001%, with the balance being Ni.
[0040] Step 2: The pretreated raw materials are subjected to vacuum induction melting and vacuum arc remelting in sequence to obtain preformed bars; Specifically, the pretreated raw materials are added to an alumina crucible, placed in a vacuum induction melting furnace, the furnace door is closed, and a vacuum of 4.7 × 10⁻³ Pa is drawn into the furnace. Then, Ar gas with a purity ≥ 99.999% is introduced into the furnace at a pressure of 0.12 MPa. The induction power supply is turned on, and the furnace is heated to 1600℃ at a heating rate of 8℃ / min and held for 30 minutes to completely melt and homogenize the raw materials. During this process, electromagnetic stirring (stirring frequency 55Hz) is performed to eliminate component segregation. After vacuum induction melting, a second vacuum consumable melting is performed (the furnace is drawn into a vacuum of 4.7 × 10⁻³ Pa, power 150kW) to further improve the alloy uniformity.
[0041] The alloy is machined to obtain rods for powder making.
[0042] Step 3: First, degas the preformed rods, then perform rotary electrode atomization to produce powder, and finally obtain nickel-based high-temperature alloy powder after sieving and impurity removal.
[0043] Specifically, the rods are placed in a feeding chamber with integrated heating and degassing functions for high-temperature degassing to remove water and oxygen impurities adsorbed by the rods. After cooling, the rods are directly fed from the feeding chamber to the transmission chamber for atomization and powder production by rotating electrodes.
[0044] The powder was then sieved to remove impurities. The collected powder was sieved under atmospheric protection to remove fine powder with a particle size of less than 53 μm and coarse powder with a particle size of more than 150 μm. Magnetic impurities in the powder were removed by magnetic separation device, and non-metallic impurities in the powder were removed by electrostatic separation device. Finally, it was vacuum packaged to obtain the high-purity nickel-based high-temperature alloy powder with a sphericity of 99.5% and a hollow powder rate of 0.3%.
[0045] Example 3 This embodiment provides a method for preparing a nickel-based superalloy component (the nickel-based superalloy powder used in this embodiment is prepared from Preparation Example 3), and the specific steps are as follows: Step 1: Make a sleeve according to the shape of the part and polish the inner wall of the sleeve, and then perform vacuum heat treatment on the sleeve; Specifically, a cylindrical stainless steel sheath is designed and manufactured. The inner wall of the sheath is polished (roughness Ra is 1.4μm) to remove surface oxide scale and oil stains. Then, the sheath is subjected to vacuum heat treatment (450℃, 2h) to remove any residual air and moisture in the material. Step 2: Load the nickel-based high-temperature alloy powder into the cladding, then degas the cladding, and seal the degassing hole after degassing; Specifically, nickel-based superalloy powder was loaded into a cladding. Heating and vibration were performed during the loading process to allow air and moisture adsorbed on the powder particles to escape fully, resulting in a powder filling density of 66%. After loading, degassing was performed at 500℃ for 4 hours, achieving an internal pressure of 9.9 × 10⁻⁶. -5 Pa, thereby removing air and gas adsorbed by powder inside the casing; after degassing, the degassing hole is sealed by lead seal welding to ensure the airtightness of the casing; Step 3: After hot isostatic pressing, remove the sealed cladding to obtain nickel-based high-temperature alloy components for molten salt reactors.
[0046] Specifically, the sealed cladding is placed in a hot isostatic pressing furnace and held at 1250℃ and 123MPa for 3 hours to completely densify the powder. Then, it is rapidly cooled to room temperature at a cooling rate of 25℃ / min, simultaneously achieving powder densification and high-pressure solution heat treatment. Next, the cladding is removed by machining to obtain a nickel-based superalloy component for molten salt reactors. This component has a density of 99.8%, a uniform microstructure, a room temperature tensile strength ≥1183MPa, a yield strength ≥1077MPa, and exhibits excellent radiation resistance and corrosion resistance.
[0047] like Figure 3-5 As shown, the microstructure is uniform and fine, resulting in good strength and plasticity of the component. Y2O3 is dispersed at the grain boundaries, which can play a role in strengthening and improving radiation resistance.
[0048] Comparative Example 1 Hastelloy N alloy is a high-temperature alloy used in molten salt reactors. Nickel-based high-temperature alloy components are manufactured using a casting and forging process. It has good resistance to molten salt corrosion, but its radiation resistance is average, and it may experience high-temperature helium embrittlement.
[0049] Comparative Example 2 Inconel 625 alloy is a solid solution-strengthened superalloy with excellent overall performance. Nickel-based superalloy components are typically manufactured using a casting and forging process and have wide applications in aerospace, chemical, marine, and nuclear power (conventional components). However, Inconel 625 alloy exhibits moderate corrosion resistance in fluoride salts and poor radiation resistance, making it unsuitable for the harsh environment of molten salt reactors.
[0050] The table below compares the performance of Examples 1-3 with that of Comparative Examples 1-2: 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.
[0051] 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 nickel-based superalloy powder for molten salt reactors, characterized in that, Includes the following steps: Step 1: Weigh the raw materials according to the ingredient requirements and pre-treat the raw materials; the raw materials include Ni blocks, Cr blocks, Mo flakes, Fe-C master alloy and Y2O3 particles; Step 2: The pretreated raw materials are subjected to vacuum induction melting and vacuum arc remelting in sequence to obtain preformed bars; Step 3: First, degas the preformed rods, then perform rotary electrode atomization to produce powder, and finally obtain nickel-based high-temperature alloy powder after sieving and impurity removal.
2. The method for preparing nickel-based superalloy powder for molten salt reactors according to claim 1, characterized in that, In step one, the chemical composition of the raw materials, by mass percentage, is as follows: Cr: 5.8-8.5%, Mo: 14.4-18.3%, C: 0.02-0.1%, Fe: 2.8-4.8%, Y: 0.05-0.3%, Mn≤1%, Si≤1%, Co≤0.02%, Cu≤0.1%, Ti≤0.1%, Al≤0.1%, B≤0.005%, P≤0.005%, S≤0.005%, O≤0.01%, N≤0.01%, B≤0.001%, with the balance being Ni.
3. The method for preparing nickel-based superalloy powder for molten salt reactors according to claim 1, characterized in that, In step one, the pretreatment of the raw materials involves ultrasonic cleaning followed by drying in a vacuum drying oven.
4. The method for preparing nickel-based superalloy powder for molten salt reactors according to claim 1, characterized in that, In step two, vacuum induction melting involves introducing Ar gas into a vacuum induction melting furnace with a vacuum degree ≤ 5×10⁻³Pa until the furnace pressure is 0.1-0.12MPa, then heating to 1550-1600℃ at a heating rate of 5-8℃ / min, holding at that temperature for 30-40min, and stirring during the heating process to complete the vacuum induction melting.
5. The method for preparing nickel-based superalloy powder for molten salt reactors according to claim 1, characterized in that, In step three, the precast bars are degassed by placing them in a feeding hopper with integrated heating and degassing functions for high-temperature degassing, followed by cooling.
6. A method for preparing high-performance molten salt reactor components, characterized in that, The high-performance molten salt reactor component is prepared from powder produced by the preparation method according to any one of claims 1 to 5, comprising the following steps: Step 1: Make a sleeve according to the shape of the part and polish the inner wall of the sleeve, and then perform vacuum heat treatment on the sleeve; Step 2: Load the nickel-based high-temperature alloy powder into the cladding, then degas the cladding, and seal the degassing hole after degassing; Step 3: After hot isostatic pressing, remove the sealed cladding to obtain nickel-based high-temperature alloy components for molten salt reactors.
7. The method for preparing a high-performance molten salt reactor component according to claim 6, characterized in that, In step two, the cladding is degassed at 400-500℃ for 4-12 hours until the internal pressure of the cladding is ≤1×10⁻⁶. -4 Pa.
8. The method for preparing a high-performance molten salt reactor component according to claim 6, characterized in that, In step three, the sealed casing is subjected to hot isostatic pressing at 1100-1260℃ and 120-150MPa for 3-5 hours, followed by cooling to room temperature at a cooling rate of 15℃ / min to 25℃ / min.
9. The method for preparing a high-performance molten salt reactor component according to claim 6, characterized in that, In step three, the density of the nickel-based high-temperature alloy component for the molten salt reactor is ≥99.8%, the tensile strength at room temperature is ≥1100MPa, and the yield strength is ≥1000MPa.
10. The application of the nickel-based high-temperature alloy component for molten salt reactors prepared by the preparation method of high-performance molten salt reactor components according to any one of claims 6 to 9 in the manufacture of fourth-generation nuclear fission molten salt reactors.