A high-toughness ultrafine-grain layered FeCrAl-based alloy material and a preparation method thereof

Abstract

This invention provides a high-strength, high-toughness, ultrafine-grained layered FeCrAl-based alloy material and its preparation method, relating to the technical fields of iron-based alloy structural materials and special alloy materials. The high-strength, high-toughness, ultrafine-grained layered FeCrAl-based alloy material provided by this invention mainly comprises a layered FeCrAl alloy matrix phase and a high-entropy alloy particle phase. The specific layered structure and composition of the matrix phase are beneficial to improving the strength and toughness of the alloy material. Furthermore, the specific composition and specific addition ratio of Al... x CrFeNi y Mo z The high-entropy alloy particles are dispersed along the layered structure, which can play a role in dispersion strengthening. At the same time, the high-entropy alloy particles can also refine the grains of the FeCrAl alloy matrix phase, achieving the effect of fine grain strengthening, which can further improve the strength and toughness of the alloy material.

Description

Technical Field

[0001] This invention belongs to the technical field of iron-based alloy structural materials and special alloy materials, and mainly relates to a high-strength and tough ultrafine-grained layered FeCrAl-based alloy material and its preparation method. Background Technology

[0002] Compared to traditional fossil fuels, nuclear energy boasts advantages such as cleanliness, high energy density, and resource sustainability, leading to its rapid and steady development in recent years. However, nuclear safety remains a long-term and complex challenge. Nuclear fuel cladding materials, as the sealed outer shell of nuclear fuel, are one of the most critical barriers to ensuring nuclear safety. Traditional cladding materials are typically made of zirconium alloys. Compared to zirconium alloys, FeCrAl alloys exhibit slower oxidation in high-temperature steam and, due to their low radiation expansion, have become a promising alternative to zirconium alloy cladding materials.

[0003] Currently, the main research direction for applying FeCrAl alloys to cladding materials is how to further improve the room temperature and high temperature properties of FeCrAl alloys so that they can meet the requirements of excellent processability at room temperature and structural safety and stability under the high-temperature operating conditions of nuclear fuel. To address these challenges, patent application number 202010697164.X discloses the preparation of a nano-ZrC dispersion-reinforced FeCrAl alloy matrix material by introducing nano-carbide ceramic particles. Its tensile strength at 800℃ can reach 114 MPa. However, due to problems such as poor wettability, poor interfacial bonding, and difficulty in uniform dispersion between nano-ZrC and the FeCrAl matrix, its room temperature elongation is only 9.8%, and its room temperature processability needs further improvement. The inventors previously disclosed in patent application 202110911531.6 the introduction of Al... 1.8 High-entropy alloy particles of CrCuFeNi2 were used to prepare FeCrAl-based alloys with a tensile strength of up to 196 MPa at 800℃, but their room temperature elongation was only 6.5%, indicating that their room temperature processability needs further improvement. Therefore, how to prepare FeCrAl-based alloy materials with excellent comprehensive properties at both room temperature and high temperature has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] To improve the overall performance of FeCrAl-based alloy materials at both room temperature and high temperature, this invention provides a high-strength and tough ultrafine-grained layered FeCrAl-based alloy material and its preparation method.

[0005] In a first aspect, the present invention provides a high-strength and tough ultrafine-grained layered FeCrAl-based alloy material, which adopts the following technical solution:

[0006] A high-strength and tough ultrafine-grained layered FeCrAl-based alloy material is disclosed. The FeCrAl-based alloy material mainly comprises a layered FeCrAl alloy matrix phase and a high-entropy alloy particle phase. The grain size of the FeCrAl alloy matrix phase is 0.7–8 μm. The FeCrAl-based alloy material utilizes a FeCrAl alloy matrix material and Al... x CrFeNi y Mo z It is prepared from high-entropy alloy particles as raw materials. Based on the total mass of the raw materials, the mass fraction of the high-entropy alloy particles is 10% to 30%, and the mass fraction of the FeCrAl alloy matrix material is 70% to 90%.

[0007] The FeCrAl alloy matrix material, by mass percentage, mainly comprises: Cr: 13%–14%, Al: 4%–5%, Mo: 1.0%–3.0%, Nb: 0.2%–2.0%, Si: 0%–1.0%, with the balance being Fe and impurities conforming to industrial standards.

[0008] The Al x CrFeNi y Mo z The x, y, and z values ​​of the high-entropy alloy particles are the atomic ratios of each component, and satisfy the following conditions: x is 0.1 to 0.7, y is 1.5 to 2.8, and z is 0.1 to 0.9.

[0009] Optionally, by mass percentage, the FeCrAl alloy matrix material mainly comprises: Cr: 13%–14%, Al: 4%–5%, Mo: 1.5%–2.5%, Nb: 0.5%–1.5%, with the balance being Fe and impurities conforming to industrial standards.

[0010] Optionally, based on the total mass of the raw materials, the mass fraction of the high-entropy alloy particles is 15% to 30%, and the mass fraction of the FeCrAl alloy matrix material is 70% to 85%.

[0011] Optionally, the Al x CrFeNi y Mo z The x, y, and z values ​​of the high-entropy alloy particles satisfy the following conditions: x is 0.1 to 0.5, y is 1.5 to 2.6, and z is 0.1 to 0.9.

[0012] Optionally, the high-entropy alloy particle phase has a particle size of 0.05–0.5 μm, and the high-entropy alloy particle phase is dispersed along the layered FeCrAl alloy matrix phase.

[0013] Optionally, the FeCrAl alloy matrix phase also contains spherical nano-AlNi phases, the particle size of which is 10–60 nm.

[0014] Optionally, the FeCrAl-based alloy material has a room temperature tensile strength of 1000 MPa or more, a room temperature elongation of 13% or more, a tensile strength at 800°C of 100 MPa or more, and an elongation at 800°C of 30% or more.

[0015] Optionally, the FeCrAl-based alloy material has a room temperature tensile strength of 1200 MPa or more, a room temperature elongation of 19% or more, a tensile strength at 800°C of 200 MPa or more, and an elongation at 800°C of 60% or more.

[0016] Secondly, this invention provides a method for preparing a high-strength, high-toughness, ultrafine-grained layered FeCrAl-based alloy material, employing the following technical solution:

[0017] (1)Al x CrFeNi y Mo z Preparation of high-entropy alloy particles:

[0018] Using Al powder, Cr powder, Fe powder, Ni powder and Mo powder as raw materials, according to Al x CrFeNi y Mo z The high-entropy alloy was designed with a molar atomic ratio of x:1:1:y:z. The raw materials were weighed and then mechanically ball-milled to alloy the alloy, yielding Al. x CrFeNi y Mo z These are high-entropy alloy particles;

[0019] (2) Preparation of composite powder:

[0020] The Al obtained in step (1) x CrFeNi y Mo z The high-entropy alloy particles and FeCrAl alloy powder are weighed according to the designed composition, and then the weighed raw materials are mixed evenly to prepare composite powder.

[0021] (3) Preparation of high-strength and tough ultrafine-grained layered FeCrAl-based alloy materials by spark plasma sintering:

[0022] The composite powder obtained in step (2) was subjected to spark plasma sintering to form a high-strength and tough ultrafine-grained layered FeCrAl-based alloy material.

[0023] Optionally, the process parameters for the discharge plasma sintering are: sintering temperature: 1000℃~1200℃, sintering pressure: 40~60MPa, and sintering holding time: 5~15min.

[0024] In summary, the present invention has at least one of the following beneficial technical effects:

[0025] 1. This invention provides a high-strength, high-toughness, ultrafine-grained layered FeCrAl-based alloy material, mainly comprising a layered FeCrAl alloy matrix phase and a high-entropy alloy particle phase. The specific layered structure and composition of the matrix phase are beneficial to improving the strength and toughness of the alloy material. Furthermore, the specific composition and specific addition ratio of Al... x CrFeNi y Mo z The high-entropy alloy particles are dispersed along the layered structure, which can play a role in dispersion strengthening. At the same time, the high-entropy alloy particles can also refine the grains of the FeCrAl alloy matrix phase, achieving the effect of fine grain strengthening, which can further improve the strength and toughness of the alloy material. In the following embodiments, the FeCrAl-based alloy material prepared by the present invention has a room temperature tensile strength of more than 1000 MPa, a room temperature elongation of more than 13%, a tensile strength of more than 100 MPa at 800℃, and an elongation of more than 30% at 800℃, which makes the alloy material have excellent room temperature processing formability and high temperature structural safety and stability.

[0026] 2. This invention provides a high-strength, high-toughness, ultrafine-grained layered FeCrAl-based alloy material, which incorporates Al with specific components and atomic ratios. x CrFeNi y Mo z High-entropy alloy particles, Al x CrFeNi y Mo z High-entropy alloys include FCC phase and Laves phase. The FCC phase has excellent interfacial bonding with the α-Fe of the alloy matrix, which is beneficial to further improve the room temperature and high temperature mechanical properties of the alloy material. The Laves phase has excellent high temperature mechanical properties, which can further improve the high temperature mechanical properties of the alloy material.

[0027] 3. The present invention provides a high-strength and tough ultrafine-grained layered FeCrAl-based alloy material, wherein spherical nano-AlNi phases are also distributed in the FeCrAl matrix phase, which can further refine the matrix phase grains, thereby further improving the room temperature and high temperature performance of the FeCrAl-based alloy material.

[0028] 4. This invention provides a method for preparing a high-strength, high-toughness, ultrafine-grained layered FeCrAl-based alloy material, combining the advantages of mechanical ball milling alloying and spark plasma sintering processes. The resulting FeCrAl-based alloy matrix has fine grains and a specific layered structure, while the Al... x CrFeNi y Mo z The high-entropy alloy particles are dispersed along the layered structure. The preparation method is simple, convenient, and highly controllable, making it suitable for large-scale mass production. Attached Figure Description

[0029] Figure 1 Al prepared in Example 1 of this invention 0.2 CrFeNi 2.5 Mo 0.8 XRD pattern of high-entropy alloy particles.

[0030] Figure 2 The image shows the XRD pattern of the FeCrAl-based alloy material prepared in Example 1 of this invention.

[0031] Figure 3 This is a SEM image of the FeCrAl-based alloy material prepared in Example 1 of the present invention.

[0032] Figure 4 , Figure 5 This is a TEM image of the FeCrAl-based alloy material prepared in Example 1 of the present invention.

[0033] Figure 6 The image shows the EBSD grains of the FeCrAl-based alloy material prepared in Example 1 of this invention.

[0034] Figure 7 The room temperature tensile stress-strain curve of the FeCrAl-based alloy material prepared in Example 1 of this invention.

[0035] Figure 8 The tensile stress-strain curve at 800℃ is shown for the FeCrAl-based alloy material prepared in Example 1 of this invention. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0037] The inventor disclosed an Al in a previously filed patent document (application number 202110911531.6). 1.8The CrCuFeNi2 high-entropy alloy particle-reinforced FeCrAl alloy cladding material boasts a room temperature strength of up to 1445 MPa and a tensile strength of up to 196 MPa at 800℃. However, its ductility and toughness are limited, with an elongation of only 6.5% at room temperature, which is unfavorable for processing into cladding tubes. Room temperature processability needs further improvement. After extensive research, the inventors discovered that adding Al to a FeCrAl matrix alloy with a specific composition... x CrFeNi y Mo z High-entropy alloy particles can be used to prepare FeCrAl-based alloy composites with specific layered structures. The FeCrAl matrix alloy phase has fine grains, achieving a fine-grained strengthening effect, while Al... x CrFeNi y Mo z The high-entropy alloy particles are uniformly dispersed along the layered interface of the matrix, and Al x CrFeNi y Mo z The high-entropy alloy particles exhibit good interfacial bonding with the FeCrAl matrix. During the plastic deformation process of the composite material, on the one hand, cracks tend to initiate and propagate along the layered interfaces of the matrix material, which can significantly reduce local stress concentration, promote plastic deformation, and thus significantly improve the toughness and plasticity of the composite material. On the other hand, Al... x CrFeNi y Mo z High-entropy alloy particles possess excellent room-temperature and high-temperature mechanical properties and high-temperature thermal stability, and also play a role in dispersion strengthening, significantly improving the overall room-temperature and high-temperature mechanical properties of composite materials. Furthermore, high-entropy alloy particles are less prone to growth at high temperatures, which is beneficial for improving the thermal stability of the alloy. In addition, because multi-principal-element high-entropy alloys themselves exhibit high phase stability and low volume expansion under irradiation conditions, adding high-entropy alloys to the FeCrAl matrix is ​​beneficial for improving radiation resistance. Meanwhile, Al... x CrFeNi y Mo z The high-entropy alloy does not contain Co and Cu elements, effectively avoiding the risk of radiation precipitation embrittlement that may occur during long-term service. This invention is based on this research.

[0038] Specifically, in some embodiments of the present invention, a high-strength and tough ultrafine-grained layered FeCrAl-based alloy material is provided. The FeCrAl-based alloy material mainly comprises a layered FeCrAl alloy matrix phase and a high-entropy alloy particle phase. The grain size of the FeCrAl alloy matrix phase is 0.7–8 μm. The FeCrAl-based alloy material uses a FeCrAl alloy matrix material and Al… x CrFeNiy Mo z It is prepared from high-entropy alloy particles as raw materials. Based on the total mass of the raw materials, the mass fraction of the high-entropy alloy particles is 10%–30%, and the mass fraction of the FeCrAl alloy matrix material is 70%–90%. Specifically, based on the mass percentage of the FeCrAl alloy matrix material, its main components include: Cr: 13%–14%, Al: 4%–5%, Mo: 1.0%–3.0%, Nb: 0.2%–2.0%, Si: 0%–1.0%, with the balance being Fe and impurities conforming to industrial standards. The Al… x CrFeNi y Mo z The x, y, and z values ​​of the high-entropy alloy particles are the atomic ratios of each component, and satisfy the following conditions: x is 0.1 to 0.7, y is 1.5 to 2.8, and z is 0.1 to 0.9.

[0039] The raw materials for alloy materials use Al with specific addition ratios and specific compositions. x CrFeNi y Mo z It is a high-entropy alloy particle, which makes Al x CrFeNi y Mo z High-entropy alloy particles are uniformly dispersed in a FeCrAl alloy matrix phase with a specific layered structure and composition, thereby achieving a dispersion strengthening effect. The specific composition of Al... x CrFeNi y Mo z The FeCrAl alloy matrix, composed of high-entropy alloy particles and specific components, exhibits excellent room-temperature and high-temperature strength and ductility, and Al... x CrFeNi y Mo z The high-entropy alloy particles are well integrated with the layered FeCrAl alloy matrix, which is beneficial for further improving the room temperature and high temperature strength, toughness, and plasticity of the alloy material. Meanwhile, Al... x CrFeNi y Mo z The high-entropy alloy particles are dispersed in the layered interface of the matrix phase, which is beneficial to refine the grains of the FeCrAl alloy matrix phase and improve the thermal stability of the FeCrAl alloy matrix phase at high temperature, thereby synergistically improving the comprehensive mechanical properties of the alloy material at room temperature and high temperature.

[0040] In some embodiments of the present invention, the FeCrAl alloy matrix material, by mass percentage, mainly comprises: Cr: 13%–14%, Al: 4%–5%, Mo: 1.5%–2.5%, Nb: 0.5%–1.5%, with the balance being Fe and impurities conforming to industrial standards. The specific composition and proportions of the alloy matrix material work synergistically to further improve the comprehensive mechanical properties of the alloy matrix material at both room temperature and high temperature.

[0041] In some embodiments of the present invention, the mass fraction of the high-entropy alloy particles is 15% to 30%, and the mass fraction of the FeCrAl alloy matrix material is 70% to 85%. The specific ratio of high-entropy alloy particles to matrix material in the alloy material is beneficial to further improve the comprehensive mechanical properties of the alloy material at room temperature and high temperature.

[0042] In some embodiments of the present invention, the Al x CrFeNi y Mo z The x, y, and z values ​​of the high-entropy alloy particles satisfy the following conditions: x is 0.1–0.5, y is 1.5–2.6, and z is 0.1–0.9. Specific compositions and proportions in the high-entropy alloy particles are beneficial for improving their comprehensive mechanical properties at both room temperature and high temperature.

[0043] In some embodiments of the present invention, the particle size of the high-entropy alloy particles is 0.05–0.5 μm, and the high-entropy alloy particles are dispersedly distributed along the layered FeCrAl alloy matrix phase. The dispersed distribution of the high-entropy alloy particles within the alloy matrix phase can achieve dispersion strengthening and refine the FeCrAl alloy matrix grains, thereby further improving the overall room-temperature and high-temperature mechanical properties of the alloy material.

[0044] In some embodiments of the present invention, spherical nano-AlNi phases are also distributed in the FeCrAl alloy matrix phase, wherein the particle size of the nano-AlNi phase is 10–60 nm. The spherical nano-AlNi phases are dispersedly distributed in the alloy matrix phase, which can further achieve the effects of dispersion strengthening and refining the grain size of the FeCrAl alloy matrix.

[0045] In some embodiments of the present invention, the FeCrAl-based alloy material has a room temperature tensile strength of 1000 MPa or more, a room temperature elongation of 13% or more, a tensile strength at 800°C of 100 MPa or more, and an elongation at 800°C of 30% or more.

[0046] In some embodiments of the present invention, the FeCrAl-based alloy material has a room temperature tensile strength of 1200 MPa or more, a room temperature elongation of 19% or more, a tensile strength at 800°C of 200 MPa or more, and an elongation at 800°C of 60% or more.

[0047] In some embodiments of the present invention, the present invention provides a method for preparing a high-strength and tough ultrafine-grained layered FeCrAl-based alloy material, comprising the following steps:

[0048] (1)Al x CrFeNi y Mo z Preparation of high-entropy alloy particles:

[0049] Using Al powder, Cr powder, Fe powder, Ni powder and Mo powder as raw materials, according to Al x CrFeNi y Mo z The high-entropy alloy was designed with a molar atomic ratio of x:1:1:y:z. The raw materials were weighed and then mechanically ball-milled to alloy the alloy, yielding Al. x CrFeNi y Mo z These are high-entropy alloy particles;

[0050] (2) Preparation of composite powder:

[0051] The Al obtained in step (1) x CrFeNi y Mo z The high-entropy alloy particles and FeCrAl alloy powder are weighed according to the designed composition, and then the weighed raw materials are mixed evenly to prepare composite powder.

[0052] (3) Preparation of high-strength and tough ultrafine-grained layered FeCrAl-based alloy materials by spark plasma sintering:

[0053] The composite powder obtained in step (2) was subjected to spark plasma sintering to form a high-strength and tough ultrafine-grained layered FeCrAl-based alloy material.

[0054] In some embodiments of the present invention, in step (1), the Al x CrFeNi y Mo z The process parameters for mechanical ball mill alloying of high-entropy alloys are: ball mill speed of 300 r / min to 400 r / min, ball milling time of 40 h to 60 h, and ball-to-material ratio of 8:1 to 15:1. These specific ball milling process parameters are beneficial for the mechanical alloying formation of Al. x CrFeNi y Moz High-entropy alloy particles.

[0055] In some embodiments of the present invention, in step (2), the raw materials are mixed by ball milling. The ball milling process parameters are: ball milling speed of 300 r / min to 400 r / min, ball milling time of 20 h to 35 h, and ball-to-material ratio of 5:1 to 10:1. Specific ball milling process parameters are beneficial to the uniform dispersion of the matrix phase and high-entropy alloy particles, and at the same time promote the formation of fine grain structure in the alloy.

[0056] In some embodiments of the present invention, the process parameters for spark plasma sintering in step (3) are: sintering temperature of 1000℃~1200℃, sintering pressure of 40~60MPa, and sintering holding time of 5~15min. This specific spark plasma sintering process is beneficial for promoting the plastic deformation of FeCrAl alloy powder to form a layered ultrafine crystalline microstructure, while not damaging the structure of AlCrFeNiMo high-entropy alloy particles, thereby effectively improving the room temperature and high-temperature strength and plasticity of FeCrAl-based alloys.

[0057] The present invention will be further described in detail below with reference to specific embodiments.

[0058] Example 1

[0059] This embodiment provides a preparation process for a high-strength and tough ultrafine-grained layered FeCrAl-based alloy material. The specific preparation steps are as follows:

[0060] (1)Al 0.2 CrFeNi 2.5 Mo 0.8 Preparation of high-entropy alloy particles:

[0061] According to the chemical formula Al of high-entropy alloy particles 0.2 CrFeNi 2.5 Mo 0.8 The raw materials were weighed and proportioned. The molar atomic ratio of Al, Cr, Fe, Ni, and Mo was 0.2:1:1:2.5:0.8. The raw material powders used were high-purity aluminum powder, chromium powder, iron powder, nickel powder, and molybdenum powder. The purity of each raw material powder was ≥99.9 wt%, and the particle size was 45 μm. The weighed raw material powders were loaded into a vacuum stainless steel ball mill jar with a ball-to-powder ratio of 12:1. 3 wt.% anhydrous ethanol was added as the ball milling medium. After sealing, the jar was evacuated to a vacuum degree below 1 Pa, and then purged with argon gas to atmospheric pressure. The vacuum stainless steel ball mill jar was then placed on a planetary high-energy ball mill for ball milling at a speed of 400 r / min for 60 h. After ball milling, the ball milling slurry was removed and dried in a vacuum drying oven to obtain high-entropy alloy particle samples.

[0062] Figure 1The XRD pattern of the high-entropy alloy particle sample prepared in Example 1 is shown below. Figure 1 It can be seen from Al 0.2 CrFeNi 2.5 Mo 0.8 The high-entropy alloy particle sample mainly consists of an FCC solid solution phase and a small amount of Laves phase.

[0063] (2) Preparation of composite powder:

[0064] The Al obtained in step (1) 0.2 CrFeNi 2.5 Mo 0.8 High-entropy alloy particles and FeCrAl alloy powder were weighed at mass fractions of 25% and 75%, respectively. The FeCrAl alloy powder had a particle size of 30 μm and a purity greater than 99.9 wt%. The composition of the FeCrAl alloy powder, by mass percentage, was as follows: Cr: 13.5%, Al: 4.5%, Mo: 2%, Nb: 1.0%, with the balance being Fe and impurities conforming to industrial standards. The weighed raw material powder was then loaded into a vacuum stainless steel ball mill jar at a ball-to-powder ratio of 7:1. 3 wt.% anhydrous ethanol was added as the milling medium. After sealing, a vacuum was evacuated to below 1 Pa, followed by purging with argon gas to atmospheric pressure. The vacuum stainless steel ball mill jar was then placed on a planetary high-energy ball mill for ball milling and mixing at a speed of 350 r / min for 30 h. After ball milling and mixing, the slurry was removed and dried in a vacuum drying oven to obtain the composite powder.

[0065] (3) Preparation of high-strength and tough ultrafine-grained layered FeCrAl-based alloy materials by spark plasma sintering:

[0066] The composite powder prepared in step (2) is filled into a graphite mold, and then the graphite mold is placed in the vacuum chamber of the spark plasma sintering equipment. The vacuum chamber is continuously evacuated to keep the pressure below 80 Pa. The composite powder is pressure sintered by pressurizing the graphite mold. The pressure applied to the graphite mold is 50 MPa. The temperature is raised to 1100 °C at a heating rate of 100 °C / min. The temperature is held and pressure is maintained for 5 min. After the sintering is completed, the heating is stopped, and the furnace is cooled to room temperature. The graphite mold is then removed, and the sintered sample is extracted from the graphite mold.

[0067] Figure 2 The XRD pattern of the sintered sample prepared in Example 1 is shown below. Figure 2 It can be seen from the data that the phase composition of FeCrAl-based alloy materials includes α-Fe phase and FCC solid solution phase, due to the raw material Al 0.2 CrFeNi 2.5 Mo 0.8The Laves phase content in high-entropy alloy particles is low and was not detected in sintered samples. Figure 3 This is a SEM image of the sintered sample prepared in Example 1. Figure 4 , Figure 5 These are TEM images of the sintered samples prepared in Example 1, from... Figure 3 , Figure 4 As can be seen, the FeCrAl matrix phase in FeCrAl-based alloys exhibits a layered distribution, while Al... 0.2 CrFeNi 2.5 Mo 0.8 The high-entropy alloy phase appears as granular particles, dispersed at the layered boundaries of the matrix phase, Al 0.2 CrFeNi 2.5 Mo 0.8 The particle size of the high-entropy alloy particles is 0.05–0.5 μm. Figure 5 It can be seen that spherical nanoparticles are also distributed in the FeCrAl matrix. The particle size of the spherical nanoparticles is measured to be 10-60 nm, and the spherical nanoparticles are AlNi phase. Figure 6 The image shows the EBSD grain size of the sintered sample prepared in Example 1. The grain size of the FeCrAl matrix phase was measured to be 0.7-8 μm.

[0068] Figure 7 , Figure 8 The figures show the room temperature and high temperature (800°C) tensile stress-strain curves of the sintered sample prepared in Example 1, respectively. The test method was to use an MTS mechanical testing machine to perform tensile tests on the sample. During the high temperature tensile test, the sample was heated from room temperature to 800°C and held for 5 minutes before the load was applied.

[0069] Example 2

[0070] The difference between Example 2 and Example 1 is that, in Example 2, the FeCrAl alloy powder composition by mass percentage is as follows: Cr: 13.5%, Al: 4.5%, Mo: 1.5%, Nb: 0.5%, with the balance being Fe and impurities conforming to industrial standards; the remaining preparation steps are the same as in Example 1, and a sintered sample is obtained.

[0071] Example 3

[0072] The difference between Example 3 and Example 1 is that, in Example 3, the composition of the FeCrAl alloy powder by mass percentage is as follows: Cr: 13.5%, Al: 4.5%, Mo: 2.5%, Nb: 1.5%, with the balance being Fe and impurities conforming to industrial standards; the remaining preparation steps are the same as in Example 1, and a sintered sample is obtained.

[0073] Example 4

[0074] The difference between Example 4 and Example 1 is that the chemical formula of the AlCrFeNiMo high-entropy alloy particles in Example 4 is Al 0.1 CrFeNi 1.5 Mo 0.1 According to the chemical formula Al of high-entropy alloy particles 0.1 CrFeNi 1.5 Mo 0.1 The ingredients were weighed and the molar atomic ratio of Al, Cr, Fe, Ni and Mo was 0.1:1:1:1.5:0.1. The remaining preparation steps were the same as in Example 1, and a sintered sample was obtained.

[0075] Example 5

[0076] The difference between Example 5 and Example 1 is that the chemical formula of the AlCrFeNiMo high-entropy alloy particles in Example 5 is Al 0.3 CrFeNi 1.8 Mo 0.3 According to the chemical formula Al of high-entropy alloy particles 0.3 CrFeNi 1.8 Mo 0.3 The ingredients were weighed and the molar atomic ratio of Al, Cr, Fe, Ni and Mo was 0.3:1:1:1.8:0.3; the remaining preparation steps were the same as in Example 1, and a sintered sample was obtained.

[0077] Example 6

[0078] The difference between Example 6 and Example 1 is that the chemical formula of the AlCrFeNiMo high-entropy alloy particles in Example 6 is Al 0.5 CrFeNi2Mo 0.5 According to high-entropy alloy particles Al 0.5 CrFeNi2Mo 0.5 The ingredients were weighed and the molar atomic ratio of Al, Cr, Fe, Ni and Mo was 0.5:1:1:2:0.5; the remaining preparation steps were the same as in Example 1, and a sintered sample was obtained.

[0079] Example 7

[0080] The difference between Example 7 and Example 1 is that in Example 7, the Al prepared in step (1) is used... 0.2 CrFeNi 2.5 Mo 0.8 High-entropy alloy particles and FeCrAl alloy powder were weighed at mass fractions of 15% and 85%, respectively; the remaining preparation steps were the same as in Example 1, and sintered samples were obtained.

[0081] Comparative Example 1

[0082] The difference between Comparative Example 1 and Example 1 is that, in Comparative Example 1, the composition of the FeCrAl alloy powder by mass percentage is as follows: Cr: 13.5%, Al: 4.5%, Mo: 3%, with the balance being Fe and impurities conforming to industrial standards; the remaining preparation steps are the same as in Example 1, and a sintered sample is obtained.

[0083] Comparative Example 2

[0084] The difference between Comparative Example 2 and Example 1 is that, in Comparative Example 2, the composition of the FeCrAl alloy powder by mass percentage is as follows: Cr: 13.5%, Al: 4.5%, Mo: 2%, Si: 1%, with the balance being Fe and impurities conforming to industrial standards; the remaining preparation steps are the same as in Example 1, and a sintered sample is obtained.

[0085] Comparative Example 3

[0086] The difference between Comparative Example 3 and Example 1 is that, in Comparative Example 3, the composition of the FeCrAl alloy powder by mass percentage is as follows: Cr: 13.5%, Al: 4.5%, Nb: 3%, with the balance being Fe and impurities conforming to industrial standards; the remaining preparation steps are the same as in Example 1, and a sintered sample is obtained.

[0087] Comparative Example 4

[0088] The difference between Comparative Example 4 and Example 1 is that the chemical formula of the AlCrFeNiMo high-entropy alloy particles in Comparative Example 4 is AlCrFeNiMo. 0.5 According to the high-entropy alloy particles AlCrFeNiMo 0.5 The ingredients were weighed and the molar atomic ratio of Al, Cr, Fe, Ni and Mo was 1:1:1:1:0.5; the remaining preparation steps were the same as in Example 1, and a sintered sample was obtained.

[0089] Comparative Example 5

[0090] The difference between Comparative Example 5 and Example 1 is that the chemical formula of the AlCrFeNiMo high-entropy alloy particles in Comparative Example 5 is Al 0.8 CrFeNi3Mo1, according to high-entropy alloy particles Al 0.8 The ingredients CrFeNi3Mo1 were weighed and the molar atomic ratio of Al, Cr, Fe, Ni and Mo was 0.8:1:1:3:1; the remaining preparation steps were the same as in Example 1, and a sintered sample was obtained.

[0091] Comparative Example 6

[0092] The difference between Comparative Example 6 and Example 1 is that in Comparative Example 6, the Al prepared in step (1) is used... 0.2 CrFeNi2.5 Mo 0.8 High-entropy alloy particles and FeCrAl alloy powder were weighed at mass fractions of 35% and 65%, respectively; the remaining preparation steps were the same as in Example 1, and sintered samples were obtained.

[0093] Comparative Example 7

[0094] The difference between Comparative Example 7 and Example 1 is that Comparative Example 7 uses an equal amount of Al. 1.8 CrCuFeNi2 replaces Al 0.2 CrFeNi 2.5 Mo 0.8 High-entropy alloy particles, according to the chemical formula Al... 1.8 The ingredients CrCuFeNi2 were weighed and mixed. The molar atomic ratio of Al, Cr, Cu, Fe and Ni was 1.8:1:1:1:2. The raw material powders were high-purity aluminum powder, chromium powder, copper powder, iron powder and nickel powder. The purity of each raw material powder was ≥99.9wt% and the particle size was 45μm. The remaining preparation steps were the same as in Example 1, and a sintered sample was obtained.

[0095] Comparative Example 8

[0096] The difference between Comparative Example 8 and Example 1 is that Comparative Example 8 uses an equal amount of nano-ZrC powder with a particle size of approximately 50 nm, instead of Al. 0.2 CrFeNi 2.5 Mo 0.8 High-entropy alloy particles; the remaining preparation steps are the same as in Example 1, and a sintered sample is obtained.

[0097] Table 1 Performance test data of FeCrAl alloy cladding materials prepared in the embodiments and comparative examples of the present invention.

[0098]

[0099]

[0100] As shown in Table 1, the FeCrAl-based alloy materials prepared in Examples 1-7 of this application all exhibit room temperature strengths above 1000 MPa, room temperature elongation above 13%, high-temperature strength (800℃) above 100 MPa, high-temperature elongation (800℃) above 30%, and high-temperature oxidation resistance (1000℃, 5h) above 1.47 × 10⁻⁶. -7 g / cm 2 ~1.81×10 -7 g / cm 2The thermal stability (change rate of mechanical properties before and after treatment at 1000℃ for 5 hours, %) is between 0.05% and 0.2%, indicating that the alloy material prepared according to the embodiments of this application possesses excellent comprehensive mechanical properties at both room temperature and high temperature, as well as good high-temperature oxidation resistance and thermal stability. Preferably, the FeCrAl-based alloy material has a room temperature tensile strength of ≥1200MPa, a room temperature elongation of ≥14%, a tensile strength at 800℃ of ≥150MPa, an elongation at 800℃ of ≥35%, and a high-temperature oxidation resistance (1000℃, 5 hours) of 1.4–1.6 × 10⁻⁶. -7 g / cm 2 The thermal stability (change rate of mechanical properties before and after treatment at 1000℃ for 5 hours, %) is between 0.05% and 0.15%. More preferably, the FeCrAl-based alloy material exhibits a room temperature tensile strength exceeding 1200 MPa, a room temperature elongation exceeding 19%, a tensile strength exceeding 200 MPa at 800℃, an elongation exceeding 60% at 800℃, and high-temperature oxidation resistance (1000℃, 5 hours) between 1.5 and 1.6 × 10⁻⁶. -7 g / cm 2 The thermal stability (the rate of change of mechanical properties before and after treatment at 1000℃ for 5 hours, %) is between 0.05% and 0.1%.

[0101] Examples 1-3 investigated the effects of elemental composition on the properties of FeCrAl-based alloys. The addition of Mo and Nb to FeCrAl alloys improved both room-temperature strength and elongation, as well as high-temperature strength and elongation. With increasing addition, both room-temperature and high-temperature comprehensive mechanical properties increased, reaching their maximum at 2% Mo and 1% Nb addition, respectively. Further increases in Mo and Nb resulted in increased room-temperature strength but decreased room-temperature elongation, and decreased high-temperature strength and elongation. Preferably, Mo was 1.0%–3.0% and Nb was 0.2%–2.0%; more preferably, Mo was 1.5%–2.5% and Nb was 0.5%–1.5%. Furthermore, Examples 1 and 1-3 investigated the synergistic effect of Mo and Nb. The combined effect of Mo and Nb significantly improved room-temperature strength and elongation compared to adding Mo, Nb, or Mo and Si alone, as well as high-temperature strength and elongation.

[0102] Examples 1, 4-6, and Comparative Examples 4-5 investigated the effect of the molar atomic ratio of AlCrFeNiMo high-entropy alloy particles on the properties of FeCrAl-based alloy materials. Too small or too large an atomic ratio of Al, Ni, and Mo is detrimental to improving the overall room-temperature and high-temperature mechanical properties of the alloy material. A ratio of x to 0.1–0.7, y to 1.5–2.8, and z to 0.1–0.9 is beneficial for achieving good overall room-temperature and high-temperature properties. The preferred ratios are x to 0.1–0.5, y to 1.5–2.6, and z to 0.1–0.9. The optimal ratio is x to 0.1–0.5, y to 1.5–2.5, and z to 0.1–0.8.

[0103] Examples 1, 7, and Comparative Example 6 investigated the effect of the addition amount of AlCrFeNiMo high-entropy alloy particles on the properties of FeCrAl-based alloy materials. With increasing addition amount of AlCrFeNiMo high-entropy alloy particles, both room-temperature and high-temperature comprehensive mechanical properties increased, reaching a maximum at 25%. Further increases resulted in decreased room-temperature strength and elongation, as well as decreased high-temperature strength and elongation. Preferably, the mass fraction of AlCrFeNiMo high-entropy alloy particles was 10%–30%, more preferably 15%–30%, and most preferably 15%–25%.

[0104] As can be seen from Example 1 and Comparative Examples 7 and 8, the addition of AlCrFeNiMo high-entropy alloy particles significantly improves the performance of FeCrAl-based alloy materials better than AlCrCuFeNi high-entropy alloy particles and ZrC nanoparticles.

[0105] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the mechanism, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high-strength, high-toughness, ultrafine-grained layered FeCrAl-based alloy material, characterized in that: The FeCrAl-based alloy material comprises a layered structure of an FeCrAl alloy matrix phase and a high-entropy alloy particle phase, the grain size of the FeCrAl alloy matrix phase is 0.7-8 μm, the FeCrAl-based alloy material is prepared from an FeCrAl alloy matrix material and Al x CrFeNi y Mo z The high-entropy alloy particle is prepared from raw materials, and the mass fraction of the high-entropy alloy particle is 15%-30% and the mass fraction of the FeCrAl alloy matrix material is 70%-85% based on the total mass of the raw materials. The FeCrAl alloy matrix material comprises, by mass percentage, Cr: 13%~14%, Al: 4%~5%, Mo: 1.5%~2.5%, Nb: 0.5%~1.5%, Si: 0~1.0%, with the balance being Fe and impurities conforming to industrial standards. The Al x CrFeNi y Mo z The x, y, and z values ​​of the high-entropy alloy particles represent the atomic ratios of each component, and satisfy the following conditions: x is 0.1~0.7, y is 1.5~2.8, and z is 0.1~0.

9. The FeCrAl alloy matrix phase also contains spherical nano-AlNi phases, the particle size of which is 10~60nm. The FeCrAl-based alloy material has a room temperature tensile strength of over 1000 MPa, a room temperature elongation of over 13%, a room temperature tensile strength of over 100 MPa, and a room temperature elongation of over 30%.

2. The high-strength and tough ultrafine-grained layered FeCrAl-based alloy material according to claim 1, characterized in that: The Al x CrFeNi y Mo z The x, y, and z of the high-entropy alloy particles satisfy the following conditions: x is 0.1~0.5, y is 1.5~2.6, and z is 0.1~0.

9.

3. The high-strength and tough ultrafine-grained layered FeCrAl-based alloy material according to claim 1, characterized in that: The high-entropy alloy particle phase has a particle size of 0.05~0.5μm and is dispersed along the layered FeCrAl alloy matrix phase.

4. The high-strength and tough ultrafine-grained layered FeCrAl-based alloy material according to claim 1, characterized in that: The FeCrAl-based alloy material has a room temperature tensile strength of ≥1200MPa, a room temperature elongation of ≥19%, a room temperature tensile strength of ≥200MPa, and a room temperature elongation of ≥60%.

5. A method for preparing a high-strength, high-toughness, ultrafine-grained layered FeCrAl-based alloy material according to any one of claims 1 to 4, characterized in that: Includes the following steps: (1) Al x CrFeNi y Mo z Preparation of high-entropy alloy particles: Using Al powder, Cr powder, Fe powder, Ni powder and Mo powder as raw materials, according to Al x CrFeNi y Mo z The high-entropy alloy was designed with a molar atomic ratio of x:1:1:y:z. The raw materials were weighed and then mechanically ball-milled to alloy the alloy, yielding Al. x CrFeNi y Mo z High-entropy alloy particles; (2) Preparation of composite powder: The Al obtained in step (1) x CrFeNi y Mo z The high-entropy alloy particles and FeCrAl alloy powder are weighed according to the designed composition, and then the weighed raw materials are mixed evenly to prepare composite powder. (3) Preparation of high-strength and tough ultrafine-grained layered FeCrAl-based alloy materials by spark plasma sintering: The composite powder obtained in step (2) was subjected to spark plasma sintering to form a high-strength and tough ultrafine-grained layered FeCrAl-based alloy material.

6. The method for preparing the high-strength and tough ultrafine-grained layered FeCrAl-based alloy material according to claim 5, characterized in that: The process parameters for the discharge plasma sintering are as follows: sintering temperature: 1000℃~1200℃, sintering pressure: 40~60MPa, and sintering holding time: 5~15min.

Images