Cr-rich multiphase six-element non-noble metal high-entropy alloy and preparation method thereof

Abstract

This invention discloses a Cr-rich multiphase hexa-element non-noble metal high-entropy alloy and its preparation method, belonging to the field of magnetic high-entropy alloy technology. Preparation raw materials: Cr 65-70 at.%, Fe 1-5 at.%, Co 1-5 at.%, Ni 1-5 at.%, Al 10-15 at.%, and Mo 10-15 at.%, totaling 100 at.%. Preparation method: (1) Mix the raw materials evenly; (2) Continuously introduce argon gas; (3) Heat at a uniform rate, simultaneously increasing the argon gas flow rate, maintain at 1200℃ for 16 hours, and then reduce the argon gas flow rate; (4) Cool at a uniform rate, simultaneously increasing the argon gas flow rate, maintain at 900℃ for 10 hours, and then reduce the argon gas flow rate; (5) Cool at a uniform rate, maintaining the argon gas flow rate and rapidly cooling to room temperature, thus obtaining the alloy. This invention achieves a high Curie temperature Ti at low cost by combining a precise doping strategy of hexa-element non-noble metal elements with one-step heat treatment and a staged rapid cooling process. c With low saturation magnetization M s The coordinated regulation of these technologies effectively overcomes key bottlenecks such as high magnetic loss and poor magnetic stability in traditional magnetic materials, providing a material basis for the development of next-generation high-frequency and high-temperature magnetic devices.

Description

Technical Field

[0001] This invention relates to the field of magnetic high-entropy alloy technology, and more specifically to a Cr-rich multiphase hexa-eight non-noble metal high-entropy alloy and its preparation method. Background Technology

[0002] In recent years, high-entropy alloys have made significant progress in the field of magnetic materials, particularly in the development of novel functional magnetic materials, demonstrating great potential. While traditional magnetic materials such as silicon steel, permalloy, and rare-earth permanent magnets exhibit excellent performance, they suffer from significant limitations in areas such as adaptability to extreme environments, high-frequency characteristics, and cost control. High-entropy alloys, with their unique flexibility in compositional design and superior overall performance, offer a new research direction for addressing these key challenges.

[0003] In terms of materials systems, researchers have successfully developed a variety of high-entropy alloy systems with unique magnetic properties. Regarding performance optimization, current research mainly focuses on two key indicators: the Curie temperature T0. c and saturation magnetization M s Due to their excellent magnetic properties, Cr-Fe-Co-Ni based systems have become a research hotspot in recent years, thanks to their high entropy effect and short-range order control. By adding non-noble metal high-melting-point elements such as Cr, the magnetic properties can be controlled through optimization of the lattice distortion effect over a wide temperature range, significantly increasing the Curie temperature TCuri. c and reduce saturation magnetization M s Secondly, the magnetic properties can be further controlled by precisely adjusting the ratio of Fe, Co, and Ni transition metals to approximately 1:1:1 and by adding equimolar amounts of Al and Mo. Regarding the manufacturing process, a combination of one-step heat treatment and staged rapid cooling to achieve multi-stage solution treatment and aging has been proven to effectively control magnetic properties. In terms of applied research, multi-component magnetic high-entropy alloys have been successfully applied in fields meeting major national needs, such as communications, storage, computing, and detection. Their high-temperature resistance and radiation resistance provide new solutions for the aerospace industry.

[0004] However, current research on multi-component magnetic high-entropy alloys still faces the following key technical challenges:

[0005] The problem of magnetic order: Curie temperature T of conventional multi-component magnetic high-entropy alloys c Below 300K (below room temperature), the correlation mechanism between the magnetic moment order transition temperature and strength limit and the composition and phase structure of multi-component high-entropy alloys is still unclear, and there is a lack of effective control methods.

[0006] High-frequency loss problem: The saturation magnetization M of traditional multi-component magnetic high-entropy alloys at room temperature sWith a value exceeding 50 emu / g, significant eddy current losses are easily generated in high-frequency and high-temperature applications, which restricts its application in high-frequency communication, storage, computing, detection and other fields.

[0007] Process preparation issues: The phase composition of traditional multi-component magnetic high-entropy alloys is complex. The competitive relationship between the solid solution phase and the intermetallic compound phase makes it difficult to precisely control the magnetic properties. Existing preparation processes are difficult to achieve simple and low-cost preparation.

[0008] Cost and application issues: While adding precious metal elements (such as Pt and Pd) can improve magnetic properties, it significantly increases costs; while conventional non-precious metal systems struggle to achieve high Curie temperatures (Ti). c and low magnetization M s Specific magnetic requirements.

[0009] Therefore, overcoming the challenges of magnetic ordering, high-frequency loss, process preparation, and cost application of multi-component magnetic high-entropy alloys is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0010] In view of this, the purpose of this invention is to provide a Cr-rich multiphase hexa-eight non-noble metal high-entropy alloy and its preparation method, so as to overcome the shortcomings of the prior art.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] A Cr-rich multiphase hexa-element non-precious metal high-entropy alloy comprises the following raw materials in atomic percentages (at.%): Cr 65-70 at.%, Fe 1-5 at.%, Co 1-5 at.%, Ni 1-5 at.%, Al 10-15 at.%, and Mo 10-15 at.% (totaling 100 at.%).

[0013] Furthermore, the aforementioned Cr-rich multiphase hexavalent non-precious metal high-entropy alloy comprises the following raw materials in atomic percentages: Cr 66 at.%, Fe 4 at.%, Co 4 at.%, Ni 4 at.%, Al 11 at.%, and Mo 11 at.%.

[0014] This invention Cr 66 Fe4Co4Ni4Al 11 Mo 11 Hexa-element non-precious metal high-entropy alloys have BCC (body-centered cubic), FCC (face-centered cubic), and HCP (hexagonal close-packed) multiphase structures.

[0015] A method for preparing the above-mentioned Cr-rich multiphase hexa-eight-membered non-noble metal high-entropy alloy specifically includes the following steps:

[0016] (1) Mix ultrafine Cr, Fe, Co, Ni, Al and Mo non-precious metal element powders evenly according to the above atomic percentages to obtain reaction raw materials;

[0017] (2) First, place the reaction raw materials in a tube furnace, and then continuously introduce argon gas to reduce the oxygen content in the furnace to below 50 ppm;

[0018] (3) Control the tube furnace to heat up at a uniform rate, and simultaneously increase the argon flow rate. When the temperature reaches 1200℃, maintain it for 16 hours and reduce the argon flow rate.

[0019] (4) Control the tube furnace to cool down at a uniform rate, and simultaneously increase the argon flow rate. When the temperature drops to 900℃, maintain it for 10 hours and then reduce the argon flow rate.

[0020] (5) Control the tube furnace to cool down at a uniform rate, maintain the argon flow rate and cool to room temperature to obtain a Cr-rich multiphase six-element non-precious metal high-entropy alloy.

[0021] The one-step heat treatment and staged rapid cooling process of this invention can control the grain size of the Cr-Fe-Co-Ni-Al-Mo six-element non-noble metal high-entropy alloy by adjusting the cooling rate to 20-50℃ / min, and can obtain a spherical structure with a grain size of 200-300μm.

[0022] This invention achieves spherical Cr through a low-cost one-step heat treatment and a staged rapid cooling process. 66 Fe4Co4Ni4Al 11 Mo 11 Directional preparation and specific magnetic properties of hexa-element non-precious metal high-entropy alloys.

[0023] Furthermore, in step (1) above, the ultrafine Cr, Fe, Co, Ni, Al and Mo non-precious metal element powders are all spherical, with a purity ≥99.5%, preferably 99.95%, and a particle size of 50-100μm.

[0024] Furthermore, in step (2) above, the purity of argon gas is ≥99.999%, the initial flow rate is 0.3-0.7 L / min, and the flow lasts for 10-15 min.

[0025] The further beneficial effect of the above-mentioned method is that by using high-purity argon (Ar≥99.999%) as a protective agent, the oxygen (O2) content in the tubular furnace is continuously reduced to below 50ppm, ensuring that the tubular furnace is in a low-oxygen environment.

[0026] Furthermore, in step (3) above, the rate of uniform heating is 10℃ / min; the flow rate of argon gas is increased to 1.3-1.7L / min; and the flow rate of argon gas is decreased to 0.6-1.0L / min.

[0027] The further beneficial effects of the above-mentioned method are that it maintains a stable oxygen-free environment, inhibits powder surface oxidation, and promotes the diffusion balance of Cr, Fe, Co, Ni, Al and Mo elements.

[0028] Furthermore, in step (4) above, the rate of uniform cooling is 20℃ / min; the flow rate of argon gas is increased to 0.8-1.2L / min; and the flow rate of argon gas is decreased to 0.3-0.7L / min.

[0029] The further beneficial effect of adopting the above method is to regulate the precipitation of BCC (body-centered cubic) + FCC (face-centered cubic) + HCP (hexagonal close-packed) multiphase.

[0030] Furthermore, in step (5) above, the rate of uniform cooling is 30℃ / min.

[0031] The further beneficial effects of adopting the above are that it maintains argon circulation, reduces thermal stress-induced cracks, and ensures thorough sieving.

[0032] This invention also claims the application of the above-mentioned Cr-rich multiphase hexa-eight-membered non-noble metal high-entropy alloy or the Cr-rich multiphase hexa-eight-membered non-noble metal high-entropy alloy prepared by the above-mentioned preparation method in the preparation of a new generation of high-frequency, high-temperature magnetic devices.

[0033] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] 1. Low cost: The design adopts a non-precious metal element system, that is, a Cr-rich matrix with precise control of the proportion of transition metal elements (Fe:Co:Ni = 1:1:1) and the addition of Al and Mo elements in equimolar ratio. Compared with traditional multi-component magnetic high-entropy alloys containing precious metal elements (such as Pt, Pd, etc.), the material and processing costs are significantly reduced, which has an outstanding cost advantage.

[0035] 2. Simple process: A specific spherical hexagonal non-precious metal high-entropy alloy is prepared by combining a six-element non-precious metal precise doping strategy with one-step heat treatment and a staged rapid cooling process, which greatly shortens the overall process cycle.

[0036] 3. Wide range of applications: High Curie temperature T c and low saturation magnetization M s It can meet the specific magnetic requirements of next-generation high-frequency and high-temperature magnetic devices for high-frequency / high-temperature communication, storage, computing, detection, and other applications.

[0037] 4. This invention achieves a high Curie temperature Ti in this high-entropy alloy at low cost by combining a precise doping strategy with six non-precious metal elements, a one-step heat treatment process, and a staged rapid cooling process. c With low saturation magnetization M sThe synergistic regulation effectively breaks through the key bottlenecks of traditional magnetic materials in high-frequency applications, such as large magnetic loss and poor magnetic stability, and provides a material basis for the development of a new generation of high-frequency and high-temperature magnetic devices.

[0038] 5. This invention improves high-entropy magnetic properties and optimizes lattice distortion effects over a wide temperature range by employing a Cr-rich matrix and precisely controlling the ratio of transition metal elements (Fe:Co:Ni = 1:1:1) and the addition of Al and Mo elements in an equimolar ratio. This results in achieving a high Curie temperature Ti. c and low magnetization M s Synergistic regulation. A high Curie temperature T0 was prepared by combining one-step heat treatment and staged rapid cooling processes. c and low magnetization M s spherical Cr 66 Fe4Co4Ni4Al 11 Mo 11 The Curie temperature T of a hexa-element non-precious metal high-entropy alloy c Above 350K (above room temperature), saturation magnetization M at room temperature s With a concentration as low as 12-14 emu / g, it has significant application value and engineering implications.

[0039] 6. This invention uses spherical ultrafine Cr, Fe, Co, Ni, Al and Mo powders as raw materials and employs a six-element non-precious metal element precise doping strategy, combined with one-step heat treatment and staged rapid cooling process, to obtain a Cr-Fe-Co-Ni-Al-Mo series six-element non-precious metal high-entropy alloy. This successfully realizes the controllable preparation of low-cost, high-performance high-entropy alloys. Due to specific functional requirements, these alloys can be widely used in a new generation of high-frequency, high-temperature magnetic devices in fields such as communication, storage, computing, and detection.

[0040] 7. The spherical Cr prepared by this invention 66 Fe4Co4Ni4Al 11 Mo 11 A high Curie temperature (T0) was achieved in a hexa-element non-precious metal high-entropy alloy through a one-step heat treatment and a staged rapid cooling process. c ≥350K) and low saturation magnetization (M s With a synergistic regulation of 12-14 emu / g, it exhibits unique functional magnetic properties. In the field of communications, it is an ideal choice for core components such as circulators and isolators in 5G / 6G base stations, and is expected to replace traditional ferrite materials. In information storage, it provides more possibilities for the development of novel high-density magnetic storage media and magnetic random access memory (MRAM). In the field of intelligent computing, it provides a high-quality material platform for the development of low-power, high-reliability magnetic logic devices and neuromorphic computing chips. In precision detection applications, it demonstrates unique advantages in high-frequency sensing, monitoring, and detection devices.

[0041] 8. This invention develops an integrated processing technology of "high-temperature solution treatment + stepped cooling," which significantly shortens the process compared to traditional multi-stage heat treatment; it enables multi-component high-entropy alloys to utilize a completely non-precious metal system, resulting in a substantial reduction in material costs compared to systems containing precious metals; and it harmonizes the high Curie temperature Ti. c With low saturation magnetization M s The combination of these technologies meets the magnetic requirements of various specific scenarios; it achieves simultaneous optimization of magnetic high-entropy alloys in three dimensions: process flow, preparation cost, and performance indicators, providing an excellent solution for next-generation key magnetic devices used in communication, storage, computing, detection and other fields. Attached Figure Description

[0042] Figure 1 A schematic diagram of the preparation method of a spherical Cr-Fe-Co-Ni-Al-Mo hexa-membered non-noble metal high-entropy alloy;

[0043] Figure 2 A one-step heat treatment and staged rapid cooling process for a spherical Cr-Fe-Co-Ni-Al-Mo hexa-element non-precious metal high-entropy alloy, along with a powder metallurgy image.

[0044] Figure 3 spherical Cr 66 Fe4Co4Ni4Al 11 Mo 11 High-magnification scanning electron microscope (SEM) images of a hexa-element non-precious metal high-entropy alloy, including (a) the whole and (b) individual powder particles and (c) the elemental content ratios of Cr, Fe, Co, Ni, Al and Mo;

[0045] Figure 4 spherical Cr 66 Fe4Co4Ni4Al 11 Mo 11 Energy dispersive X-ray spectral surface scan (EDS) distribution of a hexa-element non-noble metal high-entropy alloy;

[0046] Figure 5 spherical Cr 66 Fe4Co4Ni4Al 11 Mo 11 X-ray diffraction (XRD) pattern of a hexa-membered non-noble metal high-entropy alloy, rich in BCC (body-centered cubic), FCC (face-centered cubic), and HCP (hexagonal close-packed) multiphases;

[0047] Figure 6 spherical Cr 66 Fe4Co4Ni4Al 11 Mo 11 Magnetization curves (MH) of a hexa-element non-precious metal high-entropy alloy;

[0048] Figure 7 spherical Cr 66 Fe4Co4Ni4Al 11 Mo 11 Arrott plot of hexa-element non-precious metal high-entropy alloys. Detailed Implementation

[0049] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] Example 1

[0051] A Cr-rich multiphase hexa-membered non-precious metal high-entropy alloy comprising the following atomic percentages of raw materials: Cr 66 at.%, Fe 4 at.%, Co 4 at.%, Ni 4 at.%, Al 11 at.%, and Mo 11 at.%.

[0052] Preparation method as follows Figure 1 and Figure 2 As shown, the specific steps include:

[0053] (1) Spherical, 99.95% pure, 50-100μm ultrafine Cr, Fe, Co, Ni, Al and Mo non-precious metal element powders were mixed evenly according to atomic percentages of Cr 66at.%, Fe 4at.%, Co 4at.%, Ni 4at.%, Al 11at.% and Mo 11at.% to obtain the reaction raw material;

[0054] (2) Place the reaction raw materials in a tube furnace, and then introduce high-purity argon gas (Ar≥99.999%) as a protective agent. The initial flow rate is set to 0.5L / min and is maintained for 10min to reduce the oxygen content in the furnace to below 50ppm.

[0055] (3) A one-step heating strategy is adopted: the tube furnace is heated at a rate of 10℃ / min, and the argon flow rate is increased to 1.5L / min. When the temperature reaches 1200℃, it is maintained for 16h, and the argon flow rate is reduced to 0.8L / min.

[0056] (4) A phased cooling strategy is adopted: In the first phase, the tube furnace is controlled to cool at a rate of 20℃ / min, while the argon flow rate is increased to 1.0L / min. When the temperature drops to 900℃, it is maintained for 10h, and the argon flow rate is reduced to 0.5L / min.

[0057] (5) A phased cooling strategy is adopted: in the second stage, the tube furnace is controlled to cool at a rate of 30℃ / min, and a low flow rate of 0.5L / min is used to quickly cool to room temperature, thus obtaining a Cr-rich multiphase six-element non-precious metal high-entropy alloy.

[0058] Performance testing

[0059] 1. The spherical Cr prepared in Example 1 66 Fe4Co4Ni4Al 11 Mo 11 The hexa-element non-noble metal high-entropy alloys exhibit highly uniform distribution characteristics at the micrometer scale, with no obvious elemental segregation or compositional fluctuations observed. The powder particles possess relatively regular spherical geometric morphologies (e.g., ...). Figure 3 (As shown).

[0060] The distribution of non-noble metal elements such as Cr, Fe, Co, Ni, Al, and Mo confirms the advantage of the multi-component high-entropy effect in suppressing the segregation of non-noble metal elements (e.g., Figure 4 As shown in the figure, this ensures the stability of the spherical structure of the multi-component non-precious metal high-entropy alloy.

[0061] 2. The spherical Cr prepared in Example 1 66 Fe4Co4Ni4Al 11 Mo 11 The hexa-membered non-noble metal high-entropy alloy possesses a multiphase structure of BCC+FCC+HCP. The three-phase structures of BCC (body-centered cubic), FCC (face-centered cubic), and HCP (hexagonal close-packed) are visible in the X-ray diffraction (XRD) spectrum of this high-entropy alloy (e.g., ...). Figure 5 (As shown).

[0062] The spherical Cr 66 Fe4Co4Ni4Al 11 Mo 11 A hexa-component non-noble metal high-entropy alloy successfully achieved the synergistic precipitation of three phases—BCC (body-centered cubic), FCC (face-centered cubic), and HCP (hexagonal close-packed)—through a one-step heat treatment and rapid cooling process, exhibiting a unique "multiphase high-entropy" effect. In this high-entropy alloy, the BCC phase, as the matrix phase, is mainly rich in Fe, Co, and Cr elements, providing a foundation for excellent ferromagnetic properties; the FCC phase is rich in Ni, Al, and Cr elements, significantly improving the material's mechanical properties and high-temperature stability; while the HCP phase, distributed at grain boundaries and phase boundaries and rich in Cr elements, endows the alloy with a high Curie temperature Ti over a wide temperature range. c With saturation magnetization M s The regulatory nature of it.

[0063] 3. The spherical Cr prepared in Example 1 66 Fe4Co4Ni4Al11 Mo 11 Hexa-element non-precious metal high-entropy alloys have high Curie temperatures Ti c With low saturation magnetization M s (like Figure 6-7 (As shown).

[0064] The spherical Cr 66 Fe4Co4Ni4Al 11 Mo 11 Hexa-element non-precious metal high-entropy alloys have successfully achieved high Curie temperatures (Ti). c ≥350K) and low saturation magnetization (M s Synergistic regulation of (12-14 emu / g):

[0065] (1) Cr-rich design (65-70 at.%)

[0066] Introducing short-range ordered Cr-Cr atom pairs enhances local spin coupling and raises the Curie temperature T. c The 3d electron band filling effect of Cr modulates the Fermi level position and optimizes the electronic state density distribution; the resulting lattice distortion suppresses the long-range ordered arrangement of magnetic moments, achieving saturation magnetization M. s The controllable reduction.

[0067] (2) Synergistic effect of Fe, Co and Ni in equal proportion

[0068] The Fe:Co:Ni ratio of 1:1:1 forms a highly disordered solid solution structure, in which the 3d orbitals of Fe, Co, and Ni form a continuously varying electron-filling sequence. Optimized magnetic exchange interaction lengths balance magnetic coupling competition, maintaining the Curie temperature T. c Simultaneously adjust the saturation magnetization M s value.

[0069] (3) Mechanism for regulating the molar ratio of Al and Mo

[0070] Al's sp electrons hybridize with transition metal d electrons, while Mo's 4d electrons introduce additional spin-orbit coupling. Al and Mo act as electron donors and acceptors, respectively, forming a space charge modulation layer, which further modulates the Curie temperature T. c With saturation magnetization M s .

[0071] The above description of the disclosed embodiments enables those skilled in the art to make or use 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. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A Cr-rich multiphase hexa-eight-membered non-noble metal high-entropy alloy, characterized in that, The raw materials include the following atomic percentages: Cr 66 at.%, Fe 4 at.%, Co 4 at.%, Ni 4 at.%, Al 11 at.%, and Mo 11 at.%.

2. A method for preparing a Cr-rich multiphase hexa-eight-membered non-noble metal high-entropy alloy as described in claim 1, characterized in that, Specifically, the following steps are included: (1) Mix ultrafine Cr, Fe, Co, Ni, Al and Mo non-precious metal element powders uniformly according to the atomic percentages described in claim 1 to obtain reaction raw materials; (2) First, place the reaction raw materials in a tube furnace, and then continuously introduce argon gas to reduce the oxygen content in the furnace to below 50 ppm; (3) Control the tube furnace to heat up at a uniform rate, and simultaneously increase the argon flow rate. When the temperature reaches 1200℃, maintain it for 16 h and reduce the argon flow rate. (4) Control the tube furnace to cool down at a uniform rate, and simultaneously increase the argon flow rate. When the temperature drops to 900℃, maintain it for 10 h and reduce the argon flow rate. (5) Control the tube furnace to cool down at a uniform rate, maintain the argon flow rate and cool rapidly to room temperature to obtain the Cr-rich multiphase hexa-eight non-precious metal high-entropy alloy.

3. The method for preparing a Cr-rich multiphase hexa-eight-membered non-noble metal high-entropy alloy according to claim 2, characterized in that, In step (1), the ultrafine Cr, Fe, Co, Ni, Al and Mo non-precious metal element powders are all spherical, with a purity ≥99.5% and a particle size of 50-100 μm.

4. The method for preparing a Cr-rich multiphase hexa-eight-membered non-noble metal high-entropy alloy according to claim 2, characterized in that, In step (2), the purity of the argon gas is ≥99.999%, the initial flow rate is 0.3-0.7 L / min, and the flow lasts for 10-15 min.

5. The method for preparing a Cr-rich multiphase hexa-eight-membered non-noble metal high-entropy alloy according to claim 2, characterized in that, In step (3), the rate of uniform heating is 10℃ / min; the flow rate of argon gas is increased to 1.3-1.7 L / min; and the flow rate of argon gas is decreased to 0.6-1.0 L / min.

6. The method for preparing a Cr-rich multiphase hexa-eight-membered non-noble metal high-entropy alloy according to claim 2, characterized in that, In step (4), the uniform cooling rate is 20℃ / min; the argon flow rate is increased to 0.8-1.2 L / min; and the argon flow rate is decreased to 0.3-0.7 L / min.

7. The method for preparing a Cr-rich multiphase hexa-eight-membered non-noble metal high-entropy alloy according to claim 2, characterized in that, In step (5), the rate of uniform cooling is 30℃ / min.

8. The application of a Cr-rich multiphase hexa-eight-membered non-noble metal high-entropy alloy as described in claim 1 or a Cr-rich multiphase hexa-eight-membered non-noble metal high-entropy alloy prepared by any one of the preparation methods described in claims 2-7 in the preparation of a new generation of high-frequency, high-temperature magnetic devices.

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