A lightweight, high-strength, high-temperature-resistant high-entropy alloy and its preparation method and application

Abstract

The present invention provides a light-weight, high-strength, high-temperature-resistant high-entropy alloy and its preparation method and application, which relates to the technical field of high-temperature alloys. The light-weight, high-strength, high-temperature-resistant high-entropy alloy is composed of seven elements: Al, Cr, Mo, Nb, Ni, Ti and V. The chemical composition is calculated by atomic percentage as follows: Al a Cr b Mo c Nb d Ni e Ti f V g , wherein 10≤a≤15, 10≤b≤20, 5≤c≤10, 10≤d≤20, 5≤e≤10, 5≤f≤10, 30≤g≤40, and a+b+c+d+e+f+g=10. The present invention prepares a lightweight, high-strength, high-temperature-resistant high-entropy alloy by weighing raw materials, polishing and ultrasonic cleaning, vacuum during smelting and casting, argon gas adjustment, multiple smelting and electromagnetic stirring, and solution treatment; the lightweight, high-strength, high-temperature-resistant high-entropy alloy has excellent compressive strength, yield strength, and hardness at room temperature and high temperature; the preparation method is simple and easy to operate, green and environmentally friendly, low cost, short process, high efficiency, and is conducive to large-scale industrial production and promotion.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature alloys, and in particular to a lightweight, high-strength, high-temperature-resistant high-entropy alloy, a preparation method, and applications thereof. Background Art

[0002] Currently, high-thrust-to-weight ratio aero-engine turbine disks primarily utilize nickel-based superalloys. However, these alloys inherently limit their thermal performance. To maintain high-temperature strength, they require the addition of high-melting-point, high-density elements (such as W, Mo, and Re). This makes them unable to meet the urgent demand for lightweight, high-strength materials for next-generation aero-engines. In recent years, high-temperature high-entropy alloys (RHEAs), owing to their unique multi-principal element design concept, have demonstrated the potential for low density, high strength, corrosion resistance, and high-temperature stability, making them a research hotspot for the next generation of high-performance metal materials.

[0003] However, existing high-temperature-resistant high-entropy alloy systems still face significant technical bottlenecks: on the one hand, to achieve high strength and heat resistance, most high-entropy alloys rely on high contents of heavy metal elements, making it difficult to meet lightweighting requirements; on the other hand, traditional high-temperature-resistant high-entropy alloys lack strengthening and oxidation resistance at high temperatures (≥800°C), resulting in a significant decrease in high-temperature strength and microstructural stability. Therefore, in order to meet the demand for lightweighting, it is of great significance to develop new lightweight, high-strength, high-temperature-resistant high-entropy alloys by introducing strengthening elements with high temperature resistance.

[0004] Currently, most methods improve the quality by adjusting the composition and / or heat treatment process, but there are still many shortcomings.

[0005] For example, Chinese patent CN119082586A discloses a lightweight, high-strength, heat-resistant high-entropy alloy and its preparation method. The alloy contains heavy metal elements. Although it can improve the tensile strength and elongation at room temperature and high temperature, the improvement is not significant. The cost of the alloy elements is high and the yield strength is low.

[0006] The same is true for Chinese patent CN115386780A. The addition of heavy metal elements increases production costs, and the addition of titanium elements for lightweighting further increases production costs. The subsequent solution aging treatment is targeted at the cast alloy with this composition, and its hardness and compressive strength are relatively low.

[0007] Chinese patent CN114277301A discloses a high-strength, high-toughness, lightweight high-entropy alloy and its preparation method. The high-cost titanium addition to the alloy clearly increases production costs, and while multiple smelting processes can remove impurities, they do not significantly improve hardness or strength. The same is true for Chinese patent CN119351848A. The addition of heavy metals increases the titanium content, and multiple smelting processes do not significantly improve yield strength and compressive strength at room or elevated temperatures.

[0008] In addition, nickel-based strengthening phases (such as γ'-Ni3Al, γ"-Ni3Nb) are still considered to be the key path to improving the temperature resistance of alloys due to their excellent coherent / semi-coherent strengthening effects and high-temperature stability. However, the introduction of Ni elements will significantly lower the melting point, bringing about great temperature resistance limitations. Summary of the Invention

[0009] In order to solve the technical problems in the prior art of lightweight, high-strength, high-temperature resistant high-entropy alloys, such as the inclusion of heavy metal elements in the composition improvement, the increase in production cost due to the addition of titanium, the small improvement in tensile strength and elongation at room temperature and high temperature, the inability of solution aging treatment to improve hardness and compressive strength to meet higher requirements, and the introduction of nickel-based strengthening phases that improve performance while reducing temperature resistance, the present invention proposes a lightweight, high-strength, high-temperature resistant high-entropy alloy, a preparation method, and applications that can solve the above technical problems. The technical solution is as follows:

[0010] A light-weight, high-strength, high-temperature-resistant high-entropy alloy, wherein the chemical composition of the light-weight, high-strength, high-temperature-resistant high-entropy alloy is as follows in atomic percentage: Al a Cr b Mo c Nb d Ni e Ti f V g , among which, 10≤a≤15, 10≤b≤20, 5≤c≤10, 10≤d≤20, 5≤e≤10, 5≤f≤10, 30≤g≤40, and a+b+c+d+e+f+g=100.

[0011] The mechanism of selecting the content of each component of the present invention is as follows:

[0012] The composition of this high-entropy alloy is designed based on the synergistic effects of multiple components and the requirements of lightweight and high-temperature resistance. A high V content is key to matrix strengthening and lightweighting. V has a density of 6.11 g / cm³, far lower than that of traditional Ni / Co-based superalloys. Furthermore, V maintains a stable BCC structure at high temperatures, providing matrix strength. A certain amount of Al, Ti, and Cr not only significantly reduces density but also improves high-temperature oxidation resistance by forming a dense oxide film. Mo and Nb are balancing elements that regulate matrix strength and plasticity. While both contribute to BCC stability and possess high solid-solution strengthening properties, high Mo contents (>8%) lead to a significant loss of plasticity. Nb contents greater than Mo contribute to a favorable ductility profile. Ni is incorporated due to the excellent strengthening properties of Ni-containing strengthening phases, particularly its strong bonding with Al, Ti, and Nb. However, Ni content must be kept low, as otherwise it significantly lowers the melting point and compromises high-temperature performance.

[0013] Optionally, the melting point of the lightweight, high-strength, high-temperature resistant high-entropy alloy is greater than 1300°C, and the density is 6.45-6.90 g / cm 3 , the phase composition is BCC phase, Nb2NiAl phase and α-Ti phase.

[0014] Optionally, the room temperature strain rate of the lightweight, high-strength, high-temperature resistant high-entropy alloy is 0.001s -1 , its room temperature yield strength is 1900-2145MPa, and its compressive strength is 1920-2190MPa; the strain rate of the lightweight, high-strength, high-temperature resistant high-entropy alloy at 850°C is 0.005s -1 , yield strength exceeds 1300MPa, compressive strength exceeds 1400MPa; strain rate is 0.005s at high temperature of 1000℃ -1 , yield strength exceeds 720MPa, compressive strength exceeds 800MPa; Vickers hardness value is 570-650HV5.

[0015] A method for preparing the lightweight, high-strength, high-temperature-resistant high-entropy alloy is provided. The method comprises the following steps:

[0016] S1. Weighing raw materials: Weighing high-purity metal particles of Al, Cr, Mo, Nb, Ni, Ti, and V with a purity of 99.9 wt% or above according to the chemical composition of the lightweight, high-strength, high-temperature-resistant high-entropy alloy, and pre-treating them to obtain treated raw materials;

[0017] S2, melting and casting: the raw materials processed in S1 are melted multiple times using a vacuum melting process, and after casting, they are cooled to room temperature in the furnace to obtain alloy ingots;

[0018] S3. Ingot solution treatment: The S2 alloy ingot is solution treated in an argon atmosphere and water-cooled to room temperature to obtain a lightweight, high-strength, high-temperature resistant high-entropy alloy.

[0019] Optionally, the weighing of S1 raw materials is as follows:

[0020] S101. All high-purity metal particles are carefully ground on the surface of the material using a grinding wheel machine or angle grinder to remove the surface oxide film or impurity layer, and then the required raw material mass is accurately weighed;

[0021] S102. Place the weighed raw materials in a beaker containing anhydrous ethanol and perform ultrasonic cleaning for 3-5 minutes. After the ultrasonic cleaning is completed, rinse with anhydrous ethanol and quickly dry to remove impurities remaining on the surface.

[0022] Optionally, S2 smelting and casting are specifically as follows:

[0023] S201. Before smelting, the smelting furnace is evacuated to a vacuum level of -4, and then high-purity argon gas with a purity of 99.999% is introduced until the gauge pressure in the furnace reaches -0.05 MPa;

[0024] S202. During the smelting process, each alloy ingot is turned over and smelted 5-7 times, each time lasting 3-5 minutes, and stirred using the electromagnetic stirring function; after the smelting is completed, it is cooled to room temperature with the furnace to obtain an alloy ingot.

[0025] Optionally, the S3 ingot solution treatment is specifically as follows:

[0026] S301, before the solution treatment, the experimental sample of the alloy ingot is sealed in a quartz tube in an argon atmosphere;

[0027] S302. Place the quartz tube with the ingot sample into a KSI 1700X box-type resistance furnace, set the heating rate to 4-6°C / min, the solution temperature to 1150-1200°C, and the insulation time to 20-24 hours. After the time is reached, quickly remove and crush the quartz tube, and drop the sample into water to cool, thereby obtaining a lightweight, high-strength, high-temperature-resistant high-entropy alloy.

[0028] Application of the lightweight, high-strength, high-temperature-resistant, high-entropy alloy or the lightweight, high-strength, high-temperature-resistant, high-entropy alloy prepared by the preparation method in the field of high-temperature structural materials.

[0029] Technical principle of the present invention:

[0030] The present invention forms an ordered strengthening phase by selecting lightweight and high-temperature stable BCC matrix elements and introducing strong ordering elements such as Ni, Al, and Ti, which synergistically improves high-temperature oxidation resistance and lightweight and high-strength properties, thereby achieving multi-phase synergistic strengthening.

[0031] Compared with the prior art, the above technical solution has at least the following beneficial effects:

[0032] The above scheme, the present invention proposes a lightweight, high-strength, high-temperature resistant high-entropy alloy and its preparation method and application, which can solve the technical problems in the existing technology that the lightweight, high-strength, high-temperature resistant high-entropy alloy contains heavy metal elements in the composition improvement, which increases the production cost by adding titanium elements, and the improvement of the tensile strength and elongation at room temperature and high temperature is not large, the improvement of the hardness and compressive strength by solid solution aging treatment cannot meet higher requirements, and the introduction of nickel-based strengthening phase will reduce the temperature resistance while improving the performance.

[0033] The present invention can remove the surface oxide film and impurities remaining on the surface through grinding and ultrasonic cleaning during raw material weighing.

[0034] The present invention can reduce the oxygen content and improve the uniformity of the components through vacuum degree, argon gas adjustment, multiple melting and electromagnetic stirring during melting and casting.

[0035] The present invention can obtain a lightweight, high-strength, high-temperature resistant high-entropy alloy with multi-phase synergistic strengthening through ingot solid solution treatment.

[0036] In summary, compared with other traditional methods, the method of the present invention prepares a lightweight, high-strength, high-temperature resistant high-entropy alloy through raw material weighing and polishing, ultrasonic cleaning, vacuum during smelting and casting, argon adjustment, multiple smelting and electromagnetic stirring, and ingot solution treatment; the lightweight, high-strength, high-temperature resistant high-entropy alloy has excellent compressive strength, yield strength and hardness at room temperature and high temperature; the preparation method is simple and easy to operate, green and environmentally friendly, low cost, short process, high efficiency, and is conducive to large-scale industrial production and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] FIG1( a ) is a 1kx secondary electron scanning image of a lightweight, high-strength, high-temperature-resistant, high-entropy alloy prepared by a method for preparing a lightweight, high-strength, high-temperature-resistant, high-entropy alloy according to Example 1 of the present invention;

[0039] FIG1( b ) is a 5kx secondary electron scanning image of a lightweight, high-strength, high-temperature-resistant, high-entropy alloy prepared by the method for preparing a lightweight, high-strength, high-temperature-resistant, high-entropy alloy according to Example 1 of the present invention;

[0040] FIG1( c ) is a 20 kx secondary electron scanning image of a lightweight, high-strength, high-temperature-resistant, high-entropy alloy prepared by the method for preparing a lightweight, high-strength, high-temperature-resistant, high-entropy alloy according to Example 1 of the present invention;

[0041] Figure 2 This is a schematic diagram of XRD analysis results of a lightweight, high-strength, high-temperature-resistant, high-entropy alloy prepared by the method for preparing a lightweight, high-strength, high-temperature-resistant, high-entropy alloy according to Example 1 of the present invention;

[0042] Figure 3 This is a schematic diagram of the compression test stress-strain curve of a lightweight, high-strength, high-temperature-resistant, high-entropy alloy prepared by the method for preparing a lightweight, high-strength, high-temperature-resistant, high-entropy alloy according to Example 1 of the present invention. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0044] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as an "exemplary" in the present invention should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete manner. Furthermore, in the embodiments of the present invention, "and / or" can mean both or either of the two.

[0045] In the embodiments of the present invention, “image” and “picture” may sometimes be used interchangeably. It should be noted that when the distinction between them is not emphasized, the meanings they intend to express are the same.

[0046] In the embodiments of the present invention, sometimes a subscript such as W1 may be written as a non-subscript such as W1. When the difference is not emphasized, the meanings to be expressed are the same.

[0047] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0048] A light-weight, high-strength, high-temperature-resistant high-entropy alloy, wherein the chemical composition of the light-weight, high-strength, high-temperature-resistant high-entropy alloy is as follows in atomic percentage: Al a Cr b Mo c Nb d Ni e Ti f V g , among which, 10≤a≤15, 10≤b≤20, 5≤c≤10, 10≤d≤20, 5≤e≤10, 5≤f≤10, 30≤g≤40, and a+b+c+d+e+f+g=100.

[0049] The mechanism of selecting the content of each component of the present invention is as follows:

[0050] The composition of this high-entropy alloy is designed based on the synergistic effects of multiple components and the requirements of lightweight and high-temperature resistance. A high V content is key to matrix strengthening and lightweighting. V has a density of 6.11 g / cm³, far lower than that of traditional Ni / Co-based superalloys. Furthermore, V maintains a stable BCC structure at high temperatures, providing matrix strength. A certain amount of Al, Ti, and Cr not only significantly reduces density but also improves high-temperature oxidation resistance by forming a dense oxide film. Mo and Nb are balancing elements that regulate matrix strength and plasticity. While both contribute to BCC stability and possess high solid-solution strengthening properties, high Mo contents (>8%) lead to a significant loss of plasticity. Nb contents greater than Mo contribute to a favorable ductility profile. Ni is incorporated due to the excellent strengthening properties of Ni-containing strengthening phases, particularly its strong bonding with Al, Ti, and Nb. However, Ni content must be kept low, as otherwise it significantly lowers the melting point and compromises high-temperature performance.

[0051] In particular, optionally, the melting point of the lightweight, high-strength, high-temperature resistant high-entropy alloy is greater than 1300°C, and the density is 6.45-6.90 g / cm 3 , the phase composition is BCC phase, Nb2NiAl phase and α-Ti phase.

[0052] In particular, the room temperature strain rate of the lightweight, high-strength, high-temperature resistant high-entropy alloy is 0.001s -1 , its room temperature yield strength is 1900-2145MPa, and its compressive strength is 1920-2190MPa; the strain rate of the lightweight, high-strength, high-temperature resistant high-entropy alloy at 850°C is 0.005s -1 , yield strength exceeds 1300MPa, compressive strength exceeds 1400MPa; strain rate is 0.005s at high temperature of 1000℃ -1 , yield strength exceeds 720MPa, compressive strength exceeds 800MPa; Vickers hardness value is 570-650HV5.

[0053] A method for preparing the lightweight, high-strength, high-temperature-resistant high-entropy alloy is provided. The method comprises the following steps:

[0054] S1. Weighing raw materials: Weighing high-purity metal particles of Al, Cr, Mo, Nb, Ni, Ti, and V with a purity of 99.9 wt% or above according to the chemical composition of the lightweight, high-strength, high-temperature-resistant high-entropy alloy, and pre-treating them to obtain treated raw materials;

[0055] S2, melting and casting: the raw materials processed in S1 are melted multiple times using a vacuum melting process, and after casting, they are cooled to room temperature in the furnace to obtain alloy ingots;

[0056] S3. Ingot solution treatment: The S2 alloy ingot is solution treated in an argon atmosphere and water-cooled to room temperature to obtain a lightweight, high-strength, high-temperature resistant high-entropy alloy.

[0057] In particular, the weighing of S1 raw materials is as follows:

[0058] S101. All high-purity metal particles are carefully ground on the surface of the material using a grinding wheel machine or angle grinder to remove the surface oxide film or impurity layer, and then the required raw material mass is accurately weighed;

[0059] S102. Place the weighed raw materials in a beaker containing anhydrous ethanol and perform ultrasonic cleaning for 3-5 minutes. After the ultrasonic cleaning is completed, rinse with anhydrous ethanol and quickly dry to remove impurities remaining on the surface.

[0060] In particular, the S2 melting and casting is as follows:

[0061] S201. Before smelting, the smelting furnace is evacuated to a vacuum level of -4, and then high-purity argon gas with a purity of 99.999% is introduced until the gauge pressure in the furnace reaches -0.05 MPa;

[0062] S202. During the smelting process, each alloy ingot is turned over and smelted 5-7 times, each time lasting 3-5 minutes, and stirred using the electromagnetic stirring function; after the smelting is completed, it is cooled to room temperature with the furnace to obtain an alloy ingot.

[0063] In particular, the S3 ingot solution treatment is as follows:

[0064] S301, before the solution treatment, the experimental sample of the alloy ingot is sealed in a quartz tube in an argon atmosphere;

[0065] S302. Place the quartz tube with the ingot sample into a KSI 1700X box-type resistance furnace, set the heating rate to 4-6°C / min, the solution temperature to 1150-1200°C, and the insulation time to 20-24 hours. After the time is reached, quickly remove and crush the quartz tube, and drop the sample into water to cool, thereby obtaining a lightweight, high-strength, high-temperature-resistant high-entropy alloy.

[0066] Application of the lightweight, high-strength, high-temperature-resistant, high-entropy alloy or the lightweight, high-strength, high-temperature-resistant, high-entropy alloy prepared by the preparation method in the field of high-temperature structural materials.

[0067] Example 1

[0068] The composition of a lightweight, high-strength, high-temperature-resistant high-entropy alloy of this embodiment is designed as follows:

[0069] Based on the thermodynamics and physical model of the high-entropy alloy phase diagram, the phase formation trend of the alloy can be determined, and key data such as phase type, precipitation temperature, and precipitation content can be obtained.

[0070] Phase formation trends in high-entropy alloy systems can be determined based on the influence of entropy-enthalpy coupling (Ω) and atomic size differences (δ) on the composition of multicomponent solid solution phases. To improve the high-temperature strength of alloy compositions, intermetallic compound phases (IM) are intentionally introduced. Based on empirical criteria reported in the literature, when 3.8% ≤ δ ≤ 6.6% and 1.1 ≤ Ω ≤ 10, the alloy composition has a tendency to form both solid solution and intermetallic compound phases. The calculation formulas for Ω and δ are shown in Equations (1) and (2).

[0071] (1)

[0072] (2)

[0073] in, is the mixing enthalpy of the alloy, is the mixing entropy of the alloy, is the weighted average melting point of the alloy, c i is the atomic ratio of the i-th element, r i is the atomic radius of element i, is the weighted average atomic radius of the alloy. and The calculation method of is shown in formulas (3) and (4).

[0074] (3)

[0075] (4)

[0076] in, is the mixing enthalpy of binary equiatomic alloy, x i or x j represents the content of the i-th or j-th element, and R is the molar gas constant.

[0077] In terms of the actual application temperature bearing capacity of the alloy, the melting point of traditional nickel-based high-temperature alloys is usually around 1200-1300℃. The melting point of the alloy components (T m ) is set to greater than 1300°C to further increase the temperature limit. The alloy melting point calculation is based on the thermodynamic equilibrium phase diagram.

[0078] The lightweight, high-strength, high-temperature-resistant, high-entropy alloy of Example 1 comprises the following atomic percentages: Al: 10%, Cr: 20%, Mo: 5%, Nb: 15%, Ni: 5%, Ti: 5%, and V: 40%. The calculated phase formation trend parameters and melting point of the alloy are shown in Table 2.

[0079] The preparation method comprises the following steps:

[0080] S1. Weighing raw materials: Weighing high-purity metal particles of Al, Cr, Mo, Nb, Ni, Ti, and V with a purity of 99.9 wt% or above according to the chemical composition of the lightweight, high-strength, high-temperature-resistant high-entropy alloy, and pre-treating them to obtain treated raw materials;

[0081] S101. All high-purity metal particles are carefully ground on the surface of the material using a grinding wheel machine or angle grinder to remove the surface oxide film or impurity layer, and then the required raw material mass is accurately weighed;

[0082] S102, placing the weighed raw materials in a beaker filled with anhydrous ethanol and performing ultrasonic cleaning for 3 minutes. After the ultrasonic cleaning is completed, rinse with anhydrous ethanol and quickly dry to remove impurities remaining on the surface;

[0083] S2, melting and casting: the raw materials processed in S1 are melted multiple times using a vacuum melting process, and after casting, they are cooled to room temperature in the furnace to obtain alloy ingots;

[0084] S201. Before smelting, the smelting furnace is evacuated to a vacuum level of -4, and then high-purity argon gas with a purity of 99.999% is introduced until the gauge pressure in the furnace reaches -0.05 MPa;

[0085] S202, during the smelting process, each alloy ingot is turned over and smelted 5 times, each time lasting for 3 minutes, and stirred using the electromagnetic stirring function; after the smelting is completed, it is cooled to room temperature with the furnace to obtain an alloy ingot;

[0086] S3, ingot solution treatment: The S2 alloy ingot is solution treated in an argon atmosphere and water-cooled to room temperature to obtain a lightweight, high-strength, high-temperature resistant high-entropy alloy;

[0087] S301, before solution treatment, first seal the experimental sample of the alloy ingot into a quartz tube in an argon atmosphere;

[0088] S302. Place the quartz tube with the ingot sample into a KSL-1700X box-type resistance furnace, set the heating rate to 6°C / min to 1200°C and keep it warm for 24 hours. After the time is reached, quickly remove and crush the quartz tube, and drop the sample into water to cool it down, thereby obtaining a lightweight, high-strength, high-temperature resistant high-entropy alloy.

[0089] The alloy density measured by the Archimedes method is 6.618±0.026g / cm 3, belonging to a lightweight, high-temperature resistant high-entropy alloy. Figures 1(a), 1(b), and 1(c) are secondary electron morphology images of the lightweight, high-strength, high-temperature resistant high-entropy alloy at 1k, 5k, and 20k magnifications, respectively. P1-P3 are EDS element scans of different contrast phases in the scans, and the element distribution is shown in Table 1.

[0090] Table 1 EDS analysis results (at%)

[0091]

[0092] Furthermore, Figure 2 Figure 3 is a schematic diagram of the as-cast XRD analysis results. Combined with the energy spectrum analysis, the gray interdendritic phase is the matrix BCC phase, the gray-white dendrite arms and particles with the same contrast are Nb2NiAl phase, and the gray-black precipitates are nearly α-Ti type precipitation phases.

[0093] The stress-strain curve of the compression test of the lightweight, high-strength, high-temperature resistant high-entropy alloy prepared in this embodiment is as follows: Figure 3 As shown. The room temperature strain rate is 0.001s -1 , its room temperature yield strength is 2012MPa, and its compressive strength is 2028MPa; the strain rate of the lightweight, high-strength, high-temperature resistant high-entropy alloy at high temperature is 0.005s -1 At 850℃, the yield strength is 1322MPa and the compressive strength is 1448MPa; at 1000℃, the yield strength is 783MPa and the compressive strength is 825MPa.

[0094] The lightweight, high-strength, high-temperature-resistant high-entropy alloy has a Vickers hardness value of 600HV5.

[0095] Example 2

[0096] The lightweight, high-strength, high-temperature-resistant, high-entropy alloy of Example 2 has the following atomic percentages: Al: 10%, Cr: 15%, Mo: 10%, Nb: 20%, Ni: 5%, Ti: 10%, and V: 30%. The calculated phase formation trend parameters and melting point of this alloy are shown in Table 2.

[0097] The preparation method comprises the following steps:

[0098] S1. Weighing raw materials: Weighing high-purity metal particles of Al, Cr, Mo, Nb, Ni, Ti, and V with a purity of 99.9 wt% or above according to the chemical composition of the lightweight, high-strength, high-temperature-resistant high-entropy alloy, and pre-treating them to obtain treated raw materials;

[0099] S101. All high-purity metal particles are carefully ground on the surface of the material using a grinding wheel machine or angle grinder to remove the surface oxide film or impurity layer, and then the required raw material mass is accurately weighed;

[0100] S102, placing the weighed raw materials in a beaker filled with anhydrous ethanol and performing ultrasonic cleaning for 4 minutes. After the ultrasonic cleaning is completed, rinsing with anhydrous ethanol and rapid drying are performed to remove impurities remaining on the surface;

[0101] S2, melting and casting: the raw materials processed in S1 are melted multiple times using a vacuum melting process, and after casting, they are cooled to room temperature in the furnace to obtain alloy ingots;

[0102] S201. Before smelting, the smelting furnace is evacuated to a vacuum level of -4, and then high-purity argon gas with a purity of 99.999% is introduced until the gauge pressure in the furnace reaches -0.05 MPa;

[0103] S202. During the smelting process, each alloy ingot is turned over and smelted 7 times, each time lasting 5 minutes, and stirred using the electromagnetic stirring function; after the smelting is completed, it is cooled to room temperature with the furnace to obtain an alloy ingot.

[0104] S3, ingot solution treatment: The S2 alloy ingot is solution treated in an argon atmosphere and water-cooled to room temperature to obtain a lightweight, high-strength, high-temperature resistant high-entropy alloy;

[0105] S301, before solution treatment, first seal the experimental sample of the alloy ingot into a quartz tube in an argon atmosphere;

[0106] S302. Place the quartz tube with the ingot sample into a KSL-1700X box-type resistance furnace, set the heating rate to 5°C / min to 1150°C and keep it warm for 22 hours. After the time is up, quickly remove and crush the quartz tube, and drop the sample into water to cool it down, thereby obtaining a lightweight, high-strength, high-temperature-resistant high-entropy alloy.

[0107] The alloy prepared by this method contains BCC phase, Nb2NiAl phase and α-Ti phase. The density of the alloy measured by Archimedes method is 6.811±0.031g / cm 3 The room temperature strain rate of the alloy is 0.001s -1 , its room temperature yield strength is 1900MPa, and its compressive strength is 1920MPa; the strain rate of the lightweight, high-strength, high-temperature resistant high-entropy alloy at high temperature is 0.005s -1 The yield strength is 1302MPa and the compressive strength is 1407MPa at 850℃; the yield strength is 725MPa and the compressive strength is 800MPa at 1000℃. The Vickers hardness of the alloy is 571HV5.

[0108] Example 3

[0109] The lightweight, high-strength, high-temperature-resistant, high-entropy alloy of Example 3 has the following atomic percentages: Al: 15%, Cr: 10%, Mo: 5%, Nb: 15%, Ni: 10%, Ti: 5%, and V: 40%. The calculated phase formation trend parameters and melting point of this alloy are shown in Table 2.

[0110] The preparation method comprises the following steps:

[0111] S1. Weighing raw materials: Weighing high-purity metal particles of Al, Cr, Mo, Nb, Ni, Ti, and V with a purity of 99.9 wt% or above according to the chemical composition of the lightweight, high-strength, high-temperature-resistant high-entropy alloy, and pre-treating them to obtain treated raw materials;

[0112] S101. All high-purity metal particles are carefully ground on the surface of the material using a grinding wheel machine or angle grinder to remove the surface oxide film or impurity layer, and then the required raw material mass is accurately weighed;

[0113] S102, placing the weighed raw materials in a beaker filled with anhydrous ethanol and performing ultrasonic cleaning for 5 minutes. After the ultrasonic cleaning is completed, rinse with anhydrous ethanol and quickly dry to remove impurities remaining on the surface;

[0114] S2, melting and casting: the raw materials processed in S1 are melted multiple times using a vacuum melting process, and after casting, they are cooled to room temperature in the furnace to obtain alloy ingots;

[0115] S201. Before smelting, the smelting furnace is evacuated to a vacuum level of -4, and then high-purity argon gas with a purity of 99.999% is introduced until the gauge pressure in the furnace reaches -0.05 MPa;

[0116] S202. During the smelting process, each alloy ingot is turned over and smelted 7 times, each time lasting 4 minutes, and stirred using the electromagnetic stirring function; after the smelting is completed, it is cooled to room temperature with the furnace to obtain an alloy ingot.

[0117] S3, ingot solution treatment: The S2 alloy ingot is solution treated in an argon atmosphere and water-cooled to room temperature to obtain a lightweight, high-strength, high-temperature resistant high-entropy alloy;

[0118] S301, before solution treatment, first seal the experimental sample of the alloy ingot into a quartz tube in an argon atmosphere;

[0119] S302. Place the quartz tube with the ingot sample into a KSL-1700X box-type resistance furnace, set the heating rate to 4°C / min and heat to 1180°C for 20 hours. After the time is up, quickly remove and crush the quartz tube, and drop the sample into water to cool, thereby obtaining a lightweight, high-strength, high-temperature-resistant high-entropy alloy.

[0120] The alloy samples prepared by this method are BCC phase, Nb2NiAl phase and α-Ti phase. The density of the alloy measured by Archimedes method is 6.486±0.027g / cm 3 The room temperature strain rate of the alloy is 0.001s -1 , its room temperature yield strength is 2046MPa, and its compressive strength is 2077MPa; the strain rate of the lightweight, high-strength, high-temperature resistant high-entropy alloy at high temperature is 0.005s -1 The yield strength is 1350MPa and the compressive strength is 1496MPa at 850℃; the yield strength is 786MPa and the compressive strength is 835MPa at 1000℃. The Vickers hardness of the alloy is 633HV5.

[0121] Example 4

[0122] The lightweight, high-strength, high-temperature-resistant, high-entropy alloy of Example 4 has the following atomic percentages: Al: 10%, Cr: 15%, Mo: 10%, Nb: 20%, Ni: 5%, Ti: 5%, and V: 35%. The calculated phase formation trend parameters and melting point of this alloy are shown in Table 2.

[0123] The preparation method comprises the following steps:

[0124] S1. Weighing raw materials: Weighing high-purity metal particles of Al, Cr, Mo, Nb, Ni, Ti, and V with a purity of 99.9 wt% or above according to the chemical composition of the lightweight, high-strength, high-temperature-resistant high-entropy alloy, and pre-treating them to obtain treated raw materials;

[0125] S101. All high-purity metal particles are carefully ground on the surface of the material using a grinding wheel machine or angle grinder to remove the surface oxide film or impurity layer, and then the required raw material mass is accurately weighed;

[0126] S102, placing the weighed raw materials in a beaker filled with anhydrous ethanol and performing ultrasonic cleaning for 3 minutes. After the ultrasonic cleaning is completed, rinse with anhydrous ethanol and quickly dry to remove impurities remaining on the surface;

[0127] S2, melting and casting: the raw materials processed in S1 are melted multiple times using a vacuum melting process, and after casting, they are cooled to room temperature in the furnace to obtain alloy ingots;

[0128] S201. Before smelting, the smelting furnace is evacuated to a vacuum level of -4, and then high-purity argon gas with a purity of 99.999% is introduced until the gauge pressure in the furnace reaches -0.05 MPa;

[0129] S202. During the smelting process, each alloy ingot is turned over and smelted 6 times, each time lasting 5 minutes, and stirred using the electromagnetic stirring function; after the smelting is completed, it is cooled to room temperature with the furnace to obtain an alloy ingot.

[0130] S3, ingot solution treatment: The S2 alloy ingot is solution treated in an argon atmosphere and water-cooled to room temperature to obtain a lightweight, high-strength, high-temperature resistant high-entropy alloy;

[0131] S301, before solution treatment, first seal the experimental sample of the alloy ingot into a quartz tube in an argon atmosphere;

[0132] S302. Place the quartz tube with the ingot sample into a KSL-1700X box-type resistance furnace, set the heating rate to 6°C / min to 1150°C and keep it warm for 24 hours. After the time is up, quickly remove and crush the quartz tube, and drop the sample into water to cool it down, thereby obtaining a lightweight, high-strength, high-temperature-resistant high-entropy alloy.

[0133] The alloy sample prepared by this method contains BCC phase, Nb2NiAl phase and α-Ti phase. The density of the alloy measured by Archimedes method is 6.901±0.021g / cm 3 The room temperature strain rate of the alloy is 0.001s -1 , its room temperature yield strength is 1958MPa, and its compressive strength is 2002MPa; the strain rate of the lightweight, high-strength, high-temperature resistant high-entropy alloy in the cast state at high temperature is 0.005s -1 The yield strength is 1310MPa and the compressive strength is 1433MPa at 850℃; the yield strength is 755MPa and the compressive strength is 816MPa at 1000℃. The Vickers hardness of the alloy is 589HV5.

[0134] Example 5

[0135] The lightweight, high-strength, high-temperature-resistant, high-entropy alloy of Example 5 has the following atomic percentages: Al: 15%, Cr: 10%, Mo: 5%, Nb: 20%, Ni: 10%, Ti: 5%, and V: 35%. The calculated phase formation trend parameters and melting point of this alloy are shown in Table 2.

[0136] The preparation method comprises the following steps:

[0137] S1. Weighing raw materials: Weighing high-purity metal particles of Al, Cr, Mo, Nb, Ni, Ti, and V with a purity of 99.9 wt% or above according to the chemical composition of the lightweight, high-strength, high-temperature-resistant high-entropy alloy, and pre-treating them to obtain treated raw materials;

[0138] S101. All high-purity metal particles are carefully ground on the surface of the material using a grinding wheel machine or angle grinder to remove the surface oxide film or impurity layer, and then the required raw material mass is accurately weighed;

[0139] S102, placing the weighed raw materials in a beaker filled with anhydrous ethanol and performing ultrasonic cleaning for 3 minutes. After the ultrasonic cleaning is completed, rinse with anhydrous ethanol and quickly dry to remove impurities remaining on the surface;

[0140] S2, melting and casting: the raw materials processed in S1 are melted multiple times using a vacuum melting process, and after casting, they are cooled to room temperature in the furnace to obtain alloy ingots;

[0141] S201. Before smelting, the smelting furnace is evacuated to a vacuum level of -4, and then high-purity argon gas with a purity of 99.999% is introduced until the gauge pressure in the furnace reaches -0.05 MPa;

[0142] S202. During the smelting process, each alloy ingot is turned over and smelted 6 times, each time lasting 4 minutes, and stirred using the electromagnetic stirring function; after the smelting is completed, it is cooled to room temperature with the furnace to obtain an alloy ingot.

[0143] S3, ingot solution treatment: The S2 alloy ingot is solution treated in an argon atmosphere and water-cooled to room temperature to obtain a lightweight, high-strength, high-temperature resistant high-entropy alloy;

[0144] S301, before solution treatment, first seal the experimental sample of the alloy ingot into a quartz tube in an argon atmosphere;

[0145] S302. Place the quartz tube with the ingot sample into a KSL-1700X box-type resistance furnace, set the heating rate to 5°C / min to 1200°C and keep it warm for 20 hours. After the time is reached, quickly remove and crush the quartz tube, and drop the sample into water to cool it down, thereby obtaining a lightweight, high-strength, high-temperature resistant high-entropy alloy.

[0146] The alloy samples prepared by this method are BCC phase, Nb2NiAl phase and α-Ti phase. The density of the alloy measured by Archimedes method is 6.612±0.044g / cm 3 The room temperature strain rate of the alloy is 0.001s -1 , its room temperature yield strength is 2145MPa, and its compressive strength is 2190MPa; the strain rate of the lightweight, high-strength, high-temperature resistant high-entropy alloy at high temperature is 0.005s -1 The yield strength is 1372MPa and the compressive strength is 1513MPa at 850℃; the yield strength is 811MPa and the compressive strength is 838MPa at 1000℃. The Vickers hardness of the alloy is 650HV5.

[0147] Table 2 Calculation results of phase formation trend parameters and melting points of alloys in Examples 1-5

[0148]

[0149] The above scheme, the present invention proposes a lightweight, high-strength, high-temperature resistant high-entropy alloy and its preparation method and application, which can solve the technical problems in the existing technology that the lightweight, high-strength, high-temperature resistant high-entropy alloy contains heavy metal elements in the composition improvement, which increases the production cost by adding titanium elements, and the improvement of the tensile strength and elongation at room temperature and high temperature is not large, the improvement of the hardness and compressive strength by solid solution aging treatment cannot meet higher requirements, and the introduction of nickel-based strengthening phase will reduce the temperature resistance while improving the performance.

[0150] The present invention can remove the surface oxide film and impurities remaining on the surface through grinding and ultrasonic cleaning during raw material weighing.

[0151] The present invention can reduce the oxygen content and improve the uniformity of the components through vacuum degree, argon gas adjustment, multiple melting and electromagnetic stirring during melting and casting.

[0152] The present invention uses an ingot solid solution method to obtain a multi-phase synergistically strengthened lightweight, high-strength, high-temperature resistant high-entropy alloy.

[0153] In summary, compared with other traditional methods, the method of the present invention prepares a lightweight, high-strength, high-temperature resistant high-entropy alloy through raw material weighing and polishing, ultrasonic cleaning, vacuum during smelting and casting, argon adjustment, multiple smelting and electromagnetic stirring, and ingot solution treatment; the lightweight, high-strength, high-temperature resistant high-entropy alloy has excellent compressive strength, yield strength and hardness at room temperature and high temperature; the preparation method is simple and easy to operate, green and environmentally friendly, low cost, short process, high efficiency, and is conducive to large-scale industrial production and promotion.

[0154] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0155] In this disclosure, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0156] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0157] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A lightweight, high-strength, high-temperature-resistant high-entropy alloy, characterized in that: The chemical composition of the lightweight, high-strength, high-temperature resistant high-entropy alloy is calculated in atomic percentage as follows: Al a Cr b Mo c Nb d Ni e Ti f V g , where 10≤a≤15, 10≤b≤20, 5≤c≤10, 10≤d≤20, 5≤e≤10, 5≤f≤10, 30≤g≤40, and a+b+c+d+e+f+g=100; The lightweight, high-strength, high-temperature resistant high-entropy alloy has a melting point exceeding 1300°C and a density of 6.45-6.90 g / cm 3 , the phase composition is BCC phase, Nb2NiAl phase and α-Ti phase.

2. The lightweight, high-strength, high-temperature-resistant high-entropy alloy according to claim 1, characterized in that: The room temperature strain rate of the lightweight, high-strength, high-temperature resistant high-entropy alloy is 0.001s -1 , its room temperature yield strength is 1900-2145MPa, and its compressive strength is 1920-2190MPa; the strain rate at 850℃ of the lightweight, high-strength, high-temperature-resistant and high-entropy composite is 0.005s -1 , yield strength exceeds 1300MPa, compressive strength exceeds 1400MPa; strain rate is 0.005s at high temperature of 1000℃ -1 , yield strength exceeds 720MPa, compressive strength exceeds 800MPa; Vickers hardness value is 570-650HV5.

3. A method for preparing a lightweight, high-strength, high-temperature-resistant high-entropy alloy according to claim 1, characterized in that: The preparation method of the lightweight, high-strength, high-temperature-resistant high-entropy alloy comprises the following steps: S1. Weighing raw materials: Weighing high-purity metal particles of Al, Cr, Mo, Nb, Ni, Ti, and V with a purity of 99.9 wt% or above according to the chemical composition of the lightweight, high-strength, high-temperature-resistant high-entropy alloy, and pre-treating them to obtain treated raw materials; S2, melting and casting: the raw materials processed in S1 are melted multiple times using a vacuum melting process, and after casting, they are cooled to room temperature in the furnace to obtain alloy ingots; S3. Ingot solution treatment: The S2 alloy ingot is solution treated in an argon atmosphere and water-cooled to room temperature to obtain a lightweight, high-strength, high-temperature resistant high-entropy alloy.

4. The method for preparing a lightweight, high-strength, high-temperature-resistant high-entropy alloy according to claim 3, characterized in that: The specific weighing of S1 raw materials is as follows: S101. All high-purity metal particles are carefully ground on the surface of the material using a grinding wheel machine or angle grinder to remove the surface oxide film or impurity layer, and then the required raw material mass is accurately weighed; S102. Place the weighed raw materials in a beaker containing anhydrous ethanol and perform ultrasonic cleaning for 3-5 minutes. After the ultrasonic cleaning is completed, rinse with anhydrous ethanol and quickly dry to remove impurities remaining on the surface.

5. The method for preparing a lightweight, high-strength, high-temperature-resistant high-entropy alloy according to claim 3, characterized in that: The details of S2 melting and casting are as follows: S201. Before smelting, the smelting furnace is evacuated to a vacuum level of -4, and then high-purity argon gas with a purity of 99.999% is introduced until the gauge pressure in the furnace reaches -0.05 MPa; S202. During the smelting process, each alloy ingot is turned over and smelted 5-7 times, each time lasting 3-5 minutes, and stirred using the electromagnetic stirring function; after the smelting is completed, it is cooled to room temperature with the furnace to obtain an alloy ingot.

6. The method for preparing a lightweight, high-strength, high-temperature-resistant high-entropy alloy according to claim 3, characterized in that: The specific solution treatment of S3 ingot is as follows: S301, before the solution treatment, the experimental sample of the alloy ingot is sealed in a quartz tube in an argon atmosphere; S302. Place the quartz tube with the ingot sample into a KSI 1700X box-type resistance furnace, set the heating rate to 4-6°C / min, the solution temperature to 1150-1200°C, and the insulation time to 20-24 hours. After the time is reached, quickly remove and crush the quartz tube, and drop the sample into water to cool, thereby obtaining a lightweight, high-strength, high-temperature-resistant high-entropy alloy.

7. Application of the lightweight, high-strength, high-temperature-resistant high-entropy alloy according to any one of claims 1-2 or the lightweight, high-strength, high-temperature-resistant high-entropy alloy prepared by the preparation method according to any one of claims 3-6 in the field of high-temperature structural materials.

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