Design and preparation method of Ni3Al-based high-entropy aluminides with excellent strong plasticity synergy

Abstract

The application provides a design and a preparation method of Ni3Al-based high-entropy aluminide with excellent strength-plasticity synergy, and relates to the technical field of component selection and preparation of advanced metal structural materials. The design needs to meet certain parameter criteria, which mainly include the enthalpy-entropy ratio based on a pseudo-binary sublattice model, atomic size difference: d0, electronegativity difference: Delta N, valence electron concentration deviation: Delta e, and total valence electron concentration: e0. Through component design, smelting and casting and cold deformation treatment, the controllable preparation of the Ni3Al-based high-entropy aluminide is realized, and the Ni3Al-based high-entropy aluminide has excellent performance, simple preparation process and low cost, and is suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention relates to the technical field of composition selection and preparation of advanced metallic structural materials, and in particular to the design and preparation method of a Ni3Al-based high-entropy aluminide with excellent strength and ductility synergy. Background Technology

[0002] The rapid development of modern industry and technology has placed more stringent requirements on the mechanical properties of structural materials. In particular, in aerospace engineering, there is an urgent need for advanced metallic structural materials with low density, excellent room temperature plasticity and high temperature strength, as well as oxidation resistance, to improve energy efficiency and engineering reliability.

[0003] Intermetallic compounds possess the toughness of metals and the high-temperature performance of ceramics, making them highly competitive advanced lightweight high-temperature metallic structural materials for the future. As a typical representative of intermetallic compounds, Ni3Al-based aluminides exhibit low density, high melting point, excellent oxidation and corrosion resistance, and a unique yield strength-temperature anomaly. Furthermore, they maintain their ordered nature near their melting point, making them promising candidates for use in key hot-end components of aero-engines, such as blades, impellers, burners, nozzles, and exhaust pipes. However, their poor room-temperature plasticity remains the biggest obstacle to their development into practical structural materials. While traditional alloying and composite methods have improved the mechanical properties of Ni3Al-based aluminides to some extent, the effects need further refinement.

[0004] Chinese patent CN117987927A discloses a Ni3Al-based single-crystal superalloy with long-term aging-stable microstructure and its preparation method. The method utilizes alloying elements such as Al, Ta, and Cr to achieve fully oxidation-resistant properties. However, the γ′ phase in the prepared alloy is controlled at 75-79 vol%, and the strength and plasticity cannot be effectively improved synergistically. Furthermore, the preparation process of the single-crystal alloy is complex and the production cost is high. In contrast, the casting of polycrystalline Ni3Al-based alloys has a simpler production process, lower cost, and is the most promising candidate for industrial-scale mass production.

[0005] In recent years, multi-principal high-entropy alloys have attracted widespread attention. They possess four major effects: high-entropy mixing entropy, hysteretic diffusion, lattice distortion effect, and cocktail effect. These effects enable the alloys to exhibit many performance advantages that are different from traditional alloys, such as high strength and toughness, corrosion resistance, and high thermal stability, once again pushing the performance of metallic structural materials to a new level.

[0006] For example, Chinese patent CN110747383A discloses a high-entropy alloy based on intermetallic compounds and its preparation method. The single-phase B2 crystal structure prepared cannot synergistically improve strength and plasticity. In particular, the large number of ordered B2 intermetallic compounds such as CoZr, CoHf, FeTi, CoTi and NiTi formed by the selection of high-cost alloying elements further proves this point.

[0007] The concept of multi-principal high entropy has brought new opportunities to improve the strength and plasticity of Ni3Al alloys.

[0008] For example, Zhao Yu's master's thesis from Harbin Institute of Technology in June 2018, titled "Design and Microstructure Study of L12 / B2 Type High-Entropy Intermetallic Compounds," designed a series of Ni3Al-based high-entropy intermetallic compounds, achieving certain performance improvements compared to traditional Ni3Al alloys. However, the designed alloys often contain some unwanted brittle intermetallic phases, resulting in insufficient plasticity and failing to achieve a synergistic improvement in strength and plasticity.

[0009] Based on this, this invention employs a multi-principal element design on the Ni and Al sublattices of Ni3Al-based aluminides to fully leverage the synergistic regulatory effect of the high entropy and long-range ordered superlattice structure of the sublattices. Furthermore, the formation of Ni3Al-based high-entropy aluminides is preliminarily predicted using phase formation criteria (enthalpy-entropy ratio, atomic size difference, electronegativity difference, valence electron concentration deviation, and total valence electron concentration) based on a pseudo-binary sublattice model. In addition, the total atomic content of Ni, Co, and Fe in the designed Ni3Al-based aluminides' Ni sublattice is 72-82%, and Al, Cr, Ti, Nb, Ta, Mo, W, or V elements are used in the Al sublattice to stably form the main L12 phase and a small amount of FCC toughening second phase. Trace amounts of boron and carbon are added to achieve excellent synergy between strength and plasticity, thereby obtaining high-performance advanced metallic structural materials suitable for applications in extreme environments such as aerospace engines and the nuclear industry. Summary of the Invention

[0010] To address the technical problems of poor room-temperature plasticity and insufficient strength in existing technologies, this invention proposes a Ni3Al-based high-entropy aluminide with excellent synergistic strength and plasticity, along with its preparation method. The technical solution is as follows:

[0011] The design of a Ni3Al-based high-entropy aluminate with excellent strong plasticity synergy requires that the design of the Ni3Al-based high-entropy aluminate meets certain parameter criteria, which mainly include the enthalpy-entropy ratio based on a pseudo-binary sublattice model. Atomic size differences: , Electronegativity differences: , Valence electron concentration deviation: , Total valence electron concentration: .

[0012] Optionally, the enthalpy-entropy ratio η based on the pseudo-binary sublattice model is expressed as:

[0013] (1);

[0014] Among them, melting temperature T m It is the average melting point of all major elements; enthalpy of mixing and mixed entropy Represented as:

[0015] (2);

[0016] (3);

[0017] in, This represents the mole fraction of element type i in the entire alloy system within sublattice A. This represents the mole fraction of element type j in the B sublattice of the entire alloy system. Let represent the enthalpy of mixing of a binary alloy with equal atomic ratios composed of the i-th and j-th elements in the A and B sublattices; R is the ideal gas constant 8.314 J. (mol K) -1 , Represents the number of sites on sublattice A. Represents the number of sites on the B sublattice. This represents the mole fraction of component i in sublattice A. This represents the mole fraction of component j in sublattice B.

[0018] Optionally, the atomic size difference is divided into atomic size differences of components on the same sublattice. Atomic size differences between components in different sublattices ;in:

[0019] Atomic size difference of components on the same sublattice Represented as:

[0020] (4);

[0021] Atomic size differences of components between different sublattices Represented as:

[0022] (5);

[0023] in, This represents the mole fraction of component i in sublattice A. r represents the mole fraction of component j in sublattice B relative to its respective sublattice. i Let r represent the atomic radius of the i-th element in sublattice A. j Let represent the atomic radius of the j-th element in the B sublattice; Represents the number of sites on sublattice A. Represents the number of sites on the B sublattice. This represents the average atomic radius on sublattice A. This represents the average atomic radius on the B sublattice, and , .

[0024] Optionally, the electronegativity difference can be divided into electronegativity differences of components on the same sublattice. Electronegativity differences between components of different sublattices ;in:

[0025] Electronegativity differences of components on the same sublattice Represented as:

[0026] (6);

[0027] Electronegativity differences among components of different sublattices Represented as;

[0028] (7);

[0029] in, This represents the mole fraction of component i in sublattice A. This represents the mole fraction of component j in sublattice B relative to its respective sublattice. This represents the mole fraction of element type i in the entire alloy system within sublattice A. This represents the mole fraction of element type j in the B sublattice of the entire alloy system. Represents the number of sites on sublattice A. Represents the number of sites on the B sublattice. Denotes the Pauling electronegativity of the i-th element in the A sublattice. Let represent the Pauling electronegativity of the j-th element in the B sublattice; This represents the average Pauling electronegativity on sublattice A. This represents the average Pauling electronegativity on the B sublattice, and , .

[0030] Optionally, the valence electron concentration deviation is divided into the valence electron concentration deviation of components on the same sublattice. Valence electron concentration deviation of components between different sublattices ;in:

[0031] Valence electron concentration deviation of components on the same sublattice Represented as:

[0032] (8);

[0033] Valence electron concentration deviation of components between different sublattices Represented as:

[0034] (9);

[0035] in, This represents the mole fraction of element type i in the entire alloy system within sublattice A. This represents the mole fraction of element type j in the B sublattice of the entire alloy system. This represents the mole fraction of component i in sublattice A. This represents the mole fraction of component j in sublattice B relative to its respective sublattice. Represents the number of sites on sublattice A. Represents the number of sites on the B sublattice. Let VEC represent the value of the i-th element in the sub-lattice A. Represents the VEC of the j-th element in the B sub-lattice; Denotes the average VEC on sublattice A. Let VEC represent the average VEC over the B sublattice, and , .

[0036] Optionally, the total valence electron concentration of the alloy Represented as:

[0037] (10);

[0038] in, This represents the mole fraction of element type i in the entire alloy system within sublattice A. This represents the mole fraction of element type j in the B sublattice of the entire alloy system. Let VEC represent the value of the i-th element in the sub-lattice A. Let VEC represent the value of the j-th element in the B sub-lattice.

[0039] Optionally, the composition of Ni3Al-based high-entropy aluminides that meet the aforementioned parameter criteria, by atomic percentage, is: Ni 25-55 at.%, Co 20-50 at.%, Fe 0-10 at.%, Al 5-20 at.%, Cr 4-15 at.%, Ti 2-15 at.%, Ta 0-5 at.%, Nb 0-5 at.%, W 0-5 at.%, Mo 0-5 at.%, V 0-5 at.%, B 0.02-1 at.%, C 0-1 at.%; the total atomic content of elements Ni, Co, and Fe is 72-82 at.%; and the sum of the atomic percentages of all components is 100%.

[0040] A method for preparing a Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy based on the aforementioned design, comprising the following steps:

[0041] S1. Conversion of alloy element content: Convert the atomic percentage of alloy elements in the above Ni3Al-based high-entropy aluminides into mass percentage to obtain the mass percentage of alloy element content.

[0042] S2. Weighing of raw materials corresponding to alloying elements: Weigh the alloying elements of S1 according to their mass percentage to obtain the raw materials corresponding to the alloying elements.

[0043] S3, Pretreatment and cleaning of raw materials corresponding to alloying elements: Pretreatment and cleaning of raw materials corresponding to alloying elements in S2 to obtain pretreated raw materials;

[0044] S4. Placement of pre-treated raw materials in a vacuum arc melting furnace: The pre-treated raw materials of S3 are melted in a vacuum arc melting furnace, and the pre-treated raw materials are placed in the vacuum arc melting furnace in sequence.

[0045] S5. Multiple melting and suction casting: The pre-treated raw material placed in S4 is melted and then suction cast multiple times. After complete cooling, it is taken out of the furnace to obtain an ingot of Ni3Al-based high-entropy aluminate with excellent strong plasticity synergy.

[0046] Optionally, the alloying elements of S2 by mass percentage are all in bulk with a purity of 99.9 wt.% or higher.

[0047] Optionally, the pretreatment of S3 involves grinding with a grinding wheel to remove surface oxide scale or impurities, then cutting it into small pieces with shearing pliers, washing it in anhydrous ethanol, and air-drying it.

[0048] Optionally, the smelting of S4: During smelting, weighed volatile and lightweight elements such as B, Al, and Cr are placed at the bottom of the crucible to prevent splashing and reduce volatilization. Other metal raw materials are placed in the copper crucible in order of increasing melting point, thereby ensuring that the high melting point elements are in direct contact with the electric arc and fully melted at high temperature. The titanium ingot is placed in the middle crucible.

[0049] Optionally, S5 is subjected to multiple melting and subsequent casting: In order to ensure that the elements are evenly distributed in the obtained button ingot, each alloy ingot is melted 6-8 times. After each melting is completed and the button ingot is cooled, it is flipped to the other side using a flipping spatula before the next melting. Finally, the alloy ingot is remelted and cast into a 10mm×10mm×60mm copper mold.

[0050] Optionally, the ingot of the Ni3Al-based high-entropy aluminide is composed of 55-100% by volume of ordered L12 phase and disordered FCC phase; the dendritic ordered L12 phase consists of nanoscale spherical particles with a size of 10-100 nm, and the interdendritic ordered L12 phase consists of micron-scale irregular cellular (chain-like) structures with a size of 1-10 μm; the disordered FCC phase is a network structure that surrounds the ordered L12 phase with an average size of 5-10 nm.

[0051] Optionally, the density of the Ni3Al-based high-entropy aluminide ingot is 7.5-8.5 g / cm³. 3 Yield strength greater than 620 MPa, tensile strength greater than 1190 MPa, yield strength ratio of 0.45-0.6, elongation greater than 25%, and strength-ductility product greater than 295 MPa·%; at 800℃, yield strength greater than 550 MPa, tensile strength greater than 550 MPa, yield strength ratio of 0.8-1, elongation greater than 1%, and strength-ductility product greater than 5.5 MPa·%.

[0052] Optionally, the method for preparing the Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy further includes the following steps:

[0053] S6. Annealing treatment: The ingot of Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy in S5 is subjected to homogenization annealing treatment, and then cooled to room temperature to obtain annealed Ni3Al-based high-entropy aluminide ingot.

[0054] S7. Cold deformation treatment: The S6 annealed Ni3Al-based high-entropy aluminide ingot is subjected to cold deformation treatment such as rolling, drawing, forging or extrusion to obtain cold-deformed Ni3Al-based high-entropy aluminide material.

[0055] S8. Recrystallization Annealing Treatment: The cold-deformed Ni3Al-based high-entropy aluminide material of S7 is subjected to recrystallization annealing treatment to finally obtain partially or completely recrystallized Ni3Al-based high-entropy aluminide cold-deformed material.

[0056] Optionally, the homogenization annealing treatment of S6 is carried out at a temperature of 1100-1300℃ for 1-48 hours, and is cooled by oil cooling or air cooling.

[0057] Optionally, the total deformation amount of the cold deformation treatment of S7 is 40-90%.

[0058] Optionally, the recrystallization annealing treatment of S8 is performed at a temperature of 1000-1300℃ for a time of 1-240 min.

[0059] Optionally, the cold-deformed Ni3Al-based high-entropy aluminide material is composed of 55-100% by volume of ordered L12 phase and disordered FCC phase; the ordered L12 phase includes spherical and rod-shaped particles, with spherical particles having a size of 50-200 nm and rod-shaped particles having a size of 0.5-2 μm; the disordered FCC phase has a network structure, which surrounds the ordered L12 phase, with an average size of 5-10 nm.

[0060] Optionally, the density of the cold-deformed Ni3Al-based high-entropy aluminide material is 7.5-8.5 g / cm³. 3 Yield strength greater than 950 MPa, tensile strength greater than 1550 MPa, yield strength ratio of 0.5-0.7, elongation greater than 20%, and strength-ductility product greater than 310 MPa·; at a high temperature of 800℃, yield strength greater than 700 MPa, tensile strength greater than 800 MPa, yield strength ratio of 0.8-1, elongation greater than 1.5%, and strength-ductility product greater than 12 MPa·.

[0061] Technical principle of the invention:

[0062] The purpose of this invention is to provide a design and preparation method for Ni3Al-based high-entropy aluminides with excellent synergistic properties of high strength and plasticity, so as to meet the mechanical performance requirements of advanced metallic structural materials for rapidly developing modern industry and technology.

[0063] The concept for achieving the above technical solution is as follows:

[0064] The main considerations include the site preference of various atoms, the selection of multiple principal elements, the determination of stoichiometry, and the addition of trace amounts of boron and carbon. A brief description is as follows:

[0065] a) It is necessary to follow the occupancy preference and stoichiometry of elements in the Ni3Al ordered superlattice structure to ensure that each atom occupies a random position in the same sublattice (chemical short-range disorder), while the two types of atoms occupying different sublattices maintain an overall ordered arrangement (chemical long-range order).

[0066] b) While maintaining the long-range order of Ni3Al-based aluminum compounds, select and adjust the types and contents of elements occupying the sublattice as needed;

[0067] c) Incorporate an appropriate amount of boron to improve the environmentally induced intergranular embrittlement problem of polycrystalline L12-type Ni3Al-based high-entropy aluminides;

[0068] d) Add an appropriate amount of carbon to improve strength and casting fluidity.

[0069] Furthermore, in a), preliminary screening of alloying elements can be performed based on the positional preferences of various atoms in Ni3Al. Although A3B-type Ni3Al aluminides have their unique stoichiometry, this ratio is not fixed at 3:1 but varies within a certain range. Fine-tuning the stoichiometry is beneficial for improving alloy plasticity, but maintaining the total percentage of Ni atoms at 75-80% is more conducive to improving the alloy's plasticity.

[0070] Furthermore, in section b), the solid solubility of each element and its contribution to the physical, chemical, and mechanical properties of the alloy need to be considered. Regarding solid solubility, elements with relatively high solid solubility, such as Co, Fe, Cr, Ti, Nb, Ta, V, Mo, and W, can be added as main elements. Co can often replace Ni in forming the L12 phase because its properties are similar to Ni, and its content can be comparable to Ni. Fe and Cr tend to accumulate in the FCC phase rather than the L12 phase, and their content should not be too high to ensure the stability of the L12 phase. The addition of an appropriate amount of Cr can not only promote the formation of a certain amount of disordered FCC phase as a plastic toughening phase to improve the toughness of the alloy, but also, with the formation of the Cr2O3 film, improve the alloy's oxidation resistance and hot corrosion resistance at medium and high temperatures. The anti-phase domain boundary energy is an important parameter in alloy design; excellent strength is closely related to high anti-phase domain boundary energy. Complex occupancy has a significant impact on the electronic structure, thereby altering the anti-phase domain boundary energy. It is worth noting that elements occupying the Al sublattice, such as Ti, Nb, Ta, V, W, and Mo, can significantly increase the APB energy, thus producing a significant strengthening effect. Elements Ti, Nb, Ta, and V also favor the formation of the L12 phase, which can stabilize Ni3Al-based high-entropy aluminides. The Ti content is generally controlled below 15 at.%, and the contents of Nb, Ta, V, Mo, W, and V are generally controlled below 5 at.%. To ensure that the L12 phase is the main phase of the alloy (volume fraction 55-100%), a relatively high Al and Ti content (Al+Ti > 12 at.%) is required. Based on these understandings, appropriate element types and contents can be selected according to requirements.

[0071] Furthermore, in c), an appropriate amount of boron (e.g., 0.1 at.%) can be added to improve the environmentally induced intergranular embrittlement problem. The boron content is typically controlled in the range of 0.05-1 at.%.

[0072] Furthermore, in step d), an appropriate amount of carbon (e.g., 0.2 at.%) is incorporated to improve strength and casting fluidity. The carbon content is typically controlled within 1 at.%.

[0073] Following the above design concept, Ni3Al-based high-entropy aluminum compounds with excellent synergistic properties of strong plasticity can be obtained.

[0074] The above technical solution has at least the following advantages compared with the existing technology:

[0075] The present invention proposes a Ni3Al-based high-entropy aluminum compound with excellent synergistic properties of strength and plasticity, and its preparation method, which can solve the technical problems of the inability to simultaneously achieve strength and plasticity in the prior art.

[0076] This invention uses phase formation criteria (enthalpy-entropy ratio, atomic size difference, electronegativity difference, valence electron concentration deviation, and total valence electron concentration) based on a pseudo-binary sublattice model to predict the formation of Ni3Al-based high-entropy aluminum compounds, reducing experimental trial-and-error costs and providing reference and guidance for the design and development of Ni3Al-based high-entropy aluminum compounds.

[0077] The Ni3Al-based high-entropy aluminides of this invention have a yield strength greater than 620 MPa and a tensile strength exceeding 1190 MPa, while maintaining a large elongation (>25%). Compared with other Ni3Al alloys and Ni3Al-based intermetallic compound alloys with simple compositions, they have superior comprehensive mechanical properties.

[0078] The preparation process of this invention is simple, highly operable, low in energy consumption and cost, suitable for industrial production, and has broad application prospects in aerospace and other fields.

[0079] In summary, compared with traditional methods for preparing Ni3Al-based aluminum compounds, the method of this invention selects the composition content of Ni3Al-based high-entropy aluminum compounds by using a phase formation criterion based on a pseudo-binary sublattice model, thereby synergistically improving the strength and plasticity of Ni3Al-based aluminum compounds that meet the criterion. This method for preparing Ni3Al-based aluminum compounds that meet the criterion is simple to operate, environmentally friendly, low in cost, short in process, and highly efficient, which is conducive to large-scale industrial production and promotion. Attached Figure Description

[0080] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0081] Figure 1This is a Ni3Al-based high-entropy aluminide Ni with excellent strong plasticity synergy, as described in Example 1 of the present invention. 38.5 Co 38.5 Al 11.5 Cr 4.5 Ti5Ta2-B 0.1 XRD pattern;

[0082] Figure 2a This is a Ni3Al-based high-entropy aluminide Ni with excellent strong plasticity synergy, as described in Example 1 of the present invention. 38.5 Co 38.5 Al 11.5 Cr 4.5 Ti5Ta2-B 0.1 SEM images of tissue morphology on a 20 μm scale;

[0083] Figure 2b This is a Ni3Al-based high-entropy aluminide Ni with excellent strong plasticity synergy, as described in Example 1 of the present invention. 38.5 Co 38.5 Al 11.5 Cr 4.5 Ti5Ta2-B 0.1 SEM images of tissue morphology on a 1μm scale;

[0084] Figure 3 This is a Ni3Al-based high-entropy aluminide Ni with excellent strong plasticity synergy, as described in Example 1 of the present invention. 38.5 Co 38.5 Al 11.5 Cr 4.5 Ti5Ta2-B 0.1 The room temperature tensile stress-strain curve. Detailed Implementation

[0085] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0086] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0087] In the embodiments of the present invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that when the distinction is not emphasized, their intended meanings are consistent.

[0088] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0089] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0090] The design of a Ni3Al-based high-entropy aluminate with excellent strong plasticity synergy requires that the design of the Ni3Al-based high-entropy aluminate meets certain parameter criteria, which mainly include the enthalpy-entropy ratio based on a pseudo-binary sublattice model. Atomic size differences: , Electronegativity differences: , Valence electron concentration deviation: , Total valence electron concentration: .

[0091] Specifically, the enthalpy-entropy ratio η based on the pseudo-binary sublattice model is expressed as:

[0092] (1);

[0093] Among them, melting temperature T m It is the average melting point of all major elements; enthalpy of mixing and mixed entropy Represented as:

[0094] (2);

[0095] (3);

[0096] in, This represents the mole fraction of element type i in the entire alloy system within sublattice A. This represents the mole fraction of element type j in the B sublattice of the entire alloy system. Let represent the enthalpy of mixing of a binary alloy with equal atomic ratios composed of the i-th and j-th elements in the A and B sublattices; R is the ideal gas constant 8.314 J. (mol K) -1 , Represents the number of sites on sublattice A. Represents the number of sites on the B sublattice. This represents the mole fraction of component i in sublattice A. This represents the mole fraction of component j in sublattice B.

[0097] Specifically, the atomic size difference is divided into atomic size differences of components on the same sublattice. Atomic size differences between components in different sublattices ;in:

[0098] Atomic size difference of components on the same sublattice Represented as:

[0099] (4);

[0100] Atomic size differences of components between different sublattices Represented as:

[0101] (5);

[0102] in, This represents the mole fraction of component i in sublattice A. r represents the mole fraction of component j in sublattice B relative to its respective sublattice. i Let r represent the atomic radius of the i-th element in sublattice A. j Let represent the atomic radius of the j-th element in the B sublattice; Represents the number of sites on sublattice A. Represents the number of sites on the B sublattice. This represents the average atomic radius on sublattice A. This represents the average atomic radius on the B sublattice, and , .

[0103] Specifically, the electronegativity difference is divided into electronegativity differences of components on the same sublattice. Electronegativity differences between components of different sublattices ;in:

[0104] Electronegativity differences of components on the same sublattice Represented as:

[0105] (6);

[0106] Electronegativity differences among components of different sublattices Represented as;

[0107] (7);

[0108] in, This represents the mole fraction of component i in sublattice A. This represents the mole fraction of component j in sublattice B relative to its respective sublattice. This represents the mole fraction of element type i in the entire alloy system within sublattice A. This represents the mole fraction of element type j in the B sublattice of the entire alloy system. Represents the number of sites on sublattice A. Represents the number of sites on the B sublattice. Denotes the Pauling electronegativity of the i-th element in the A sublattice. Let represent the Pauling electronegativity of the j-th element in the B sublattice; This represents the average Pauling electronegativity on sublattice A. This represents the average Pauling electronegativity on the B sublattice, and , .

[0109] Specifically, the valence electron concentration deviation is divided into the valence electron concentration deviation of components on the same sublattice. Valence electron concentration deviation of components between different sublattices ;in:

[0110] Valence electron concentration deviation of components on the same sublattice Represented as:

[0111] (8);

[0112] Valence electron concentration deviation of components between different sublattices Represented as:

[0113] (9);

[0114] in, This represents the mole fraction of element type i in the entire alloy system within sublattice A. This represents the mole fraction of element type j in the B sublattice of the entire alloy system. This represents the mole fraction of component i in sublattice A. This represents the mole fraction of component j in sublattice B relative to its respective sublattice. Represents the number of sites on sublattice A. Represents the number of sites on the B sublattice. Let VEC represent the value of the i-th element in the sub-lattice A. Represents the VEC of the j-th element in the B sub-lattice; Denotes the average VEC on sublattice A. Let VEC represent the average VEC over the B sublattice, and , .

[0115] Specifically, the total valence electron concentration of the alloy Represented as:

[0116] (10);

[0117] in, This represents the mole fraction of element type i in the entire alloy system within sublattice A. This represents the mole fraction of element type j in the B sublattice of the entire alloy system. Let VEC represent the value of the i-th element in the sub-lattice A. Let VEC represent the value of the j-th element in the B sub-lattice.

[0118] Specifically, the composition of Ni3Al-based high-entropy aluminides satisfying the aforementioned parameter criteria, by atomic percentage, is: Ni 25-55 at.%, Co 20-50 at.%, Fe 0-10 at.%, Al 5-20 at.%, Cr 4-15 at.%, Ti 2-15 at.%, Ta 0-5 at.%, Nb 0-5 at.%, W 0-5 at.%, Mo 0-5 at.%, V 0-5 at.%, B 0.02-1 at.%, C 0-1 at.%; the total atomic content of elements Ni, Co, and Fe is 72-82 at.%; and the sum of the atomic percentages of all components is 100%.

[0119] A method for preparing a Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy based on the aforementioned design, comprising the following steps:

[0120] S1. Conversion of alloy element content: Convert the atomic percentage of alloy elements in the above Ni3Al-based high-entropy aluminides into mass percentage to obtain the mass percentage of alloy element content.

[0121] S2. Weighing of raw materials corresponding to alloying elements: Weigh the alloying elements of S1 according to their mass percentage to obtain the raw materials corresponding to the alloying elements.

[0122] S3, Pretreatment and cleaning of raw materials corresponding to alloying elements: Pretreatment and cleaning of raw materials corresponding to alloying elements in S2 to obtain pretreated raw materials;

[0123] S4. Placement of pre-treated raw materials in a vacuum arc melting furnace: The pre-treated raw materials of S3 are melted in a vacuum arc melting furnace, and the pre-treated raw materials are placed in the vacuum arc melting furnace in sequence.

[0124] S5. Multiple melting and suction casting: The pre-treated raw material placed in S4 is melted and then suction cast multiple times. After complete cooling, it is taken out of the furnace to obtain an ingot of Ni3Al-based high-entropy aluminate with excellent strong plasticity synergy.

[0125] In particular, the alloying elements of S2 by mass percentage are all in bulk form with a purity of 99.9 wt.% or higher.

[0126] Specifically, the pretreatment of S3 involves grinding with a grinding wheel to remove surface oxide scale or impurities, then cutting it into small pieces with shearing pliers, washing it in anhydrous ethanol, and then air-drying it.

[0127] Specifically, in the S4 smelting process: during smelting, weighed volatile and lightweight elements such as B, Al, and Cr are placed at the bottom of the crucible to prevent splashing and reduce volatilization. Other metal raw materials are placed in the copper crucible in order of increasing melting point, thereby ensuring that the high melting point elements are in direct contact with the electric arc and fully melted at high temperature. The titanium ingot is placed in the middle crucible.

[0128] In particular, the S5 alloy is repeatedly melted and then cast: In order to ensure that the elements are evenly distributed in the obtained button ingot, each alloy ingot is melted 6-8 times. After each melting is completed and the button ingot is cooled, it is flipped to the other side with a flipping spatula before the next melting. Finally, the alloy ingot is remelted and cast into a 10mm×10mm×60mm copper mold.

[0129] Specifically, the ingot of the Ni3Al-based high-entropy aluminide is composed of 55-100% by volume of ordered L12 phase and disordered FCC phase; the dendritic ordered L12 phase consists of nanoscale spherical particles with a size of 10-100 nm, and the interdendritic ordered L12 phase consists of micron-scale irregular cellular (chain-like) structures with a size of 1-10 μm; the disordered FCC phase is a network structure that surrounds the ordered L12 phase with an average size of 5-10 nm.

[0130] Specifically, the density of the Ni3Al-based high-entropy aluminide ingot is 7.5-8.5 g / cm³. 3 Yield strength greater than 620 MPa, tensile strength greater than 1190 MPa, yield strength ratio of 0.45-0.6, elongation greater than 25%, and strength-ductility product greater than 295 MPa·%; at 800℃, yield strength greater than 550 MPa, tensile strength greater than 550 MPa, yield strength ratio of 0.8-1, elongation greater than 1%, and strength-ductility product greater than 5.5 MPa·%

[0131] In particular, the preparation method of the Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy further includes the following steps:

[0132] S6. Annealing treatment: The ingot of Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy in S5 is subjected to homogenization annealing treatment, and then cooled to room temperature to obtain annealed Ni3Al-based high-entropy aluminide ingot.

[0133] S7. Cold deformation treatment: The S6 annealed Ni3Al-based high-entropy aluminide ingot is subjected to cold deformation treatment such as rolling, drawing, forging or extrusion to obtain cold-deformed Ni3Al-based high-entropy aluminide material.

[0134] S8. Recrystallization Annealing Treatment: The cold-deformed Ni3Al-based high-entropy aluminide material of S7 is subjected to recrystallization annealing treatment to finally obtain partially or completely recrystallized Ni3Al-based high-entropy aluminide cold-deformed material.

[0135] Specifically, the homogenization annealing treatment of S6 is carried out at a temperature of 1100-1300℃ for 1-48 hours, and is cooled by oil cooling or air cooling.

[0136] Specifically, the total deformation of S7 during cold deformation treatment is 40-90%.

[0137] Specifically, the recrystallization annealing treatment of S8 is performed at a temperature of 1000-1300℃ for a time of 1-240 min.

[0138] Specifically, the cold-deformable Ni3Al-based high-entropy aluminide material is composed of 55-100% by volume of ordered L12 phase and disordered FCC phase; the ordered L12 phase includes spherical and rod-shaped particles with a size of 50-200 nm for spherical particles and a size of 0.5-2 μm for rod-shaped particles; the disordered FCC phase has a network structure, which surrounds the ordered L12 phase and has an average size of 5-10 nm.

[0139] Specifically, the density of the cold-deformed Ni3Al-based high-entropy aluminide material is 7.5-8.5 g / cm³. 3 Yield strength greater than 950 MPa, tensile strength greater than 1550 MPa, yield strength ratio of 0.5-0.7, elongation greater than 20%, and strength-ductility product greater than 310 MPa·; at a high temperature of 800℃, yield strength greater than 700 MPa, tensile strength greater than 800 MPa, yield strength ratio of 0.8-1, elongation greater than 1.5%, and strength-ductility product greater than 12 MPa·.

[0140] Example 1

[0141] A Ni3Al-based high-entropy aluminide that satisfies the parameter criteria has the following composition by atomic percentage: Ni 38.5 Co 38.5 Al 11.5 Cr 4.5 Ti5Ta2-B 0.1The total atomic content of elements Ni and Co is 77%.

[0142] The preparation method of the Ni3Al-based high-entropy aluminide with the aforementioned composition is as follows:

[0143] S1. Conversion of alloy element content: Convert the atomic percentage of alloy elements in the above Ni3Al-based high-entropy aluminides into mass percentage to obtain the mass percentage of alloy element content.

[0144] S2. Weighing of raw materials corresponding to alloying elements: Calculate the required content of each element based on the total weight of the alloy ingot being 50g. Weigh the alloying elements according to the mass percentage of S1. Elements Ni, Co, Al, Cr, Ti, Ta and B are all in bulk with a purity of 99.9 wt.% or higher to obtain the raw materials corresponding to the alloying elements.

[0145] S3, Pre-treatment and cleaning of raw materials corresponding to alloy elements: The raw materials corresponding to the alloy elements in S2 are pre-treated and cleaned. The pre-treatment and cleaning is carried out by grinding with a grinding wheel to remove surface oxide scale or impurities. Then, they are cut into small pieces with shearing pliers, and then cleaned in anhydrous ethanol and dried to obtain pre-treated raw materials.

[0146] S4. Placement of pretreated raw materials in a vacuum arc melting furnace: The pretreated raw materials of S3 are melted in a vacuum arc melting furnace. The pretreated raw materials are placed in the vacuum arc melting furnace in the following order: the weighed volatile and lightweight elements such as B, Al, and Cr are placed at the bottom of the crucible to prevent splashing and reduce volatilization. Other metal raw materials are placed in the copper crucible in order of melting point from low to high, so as to ensure that the high melting point elements are in direct contact with the arc and fully melted at high temperature. The titanium ingot is placed in the middle crucible.

[0147] S5. Multiple Melting and Casting: The pre-treated raw material placed in S4 is melted and cast multiple times. To ensure that the elements are evenly distributed in the resulting button ingot, each alloy ingot is melted 6-8 times. After each melting and waiting for the button ingot to cool, it is flipped to the other side using a flipping spatula before the next melting. Finally, the alloy ingot is remelted and cast into a 10mm×10mm×60mm copper mold. After complete cooling, it is taken out of the furnace to obtain an ingot of Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy.

[0148] Combination Figure 1 The XRD pattern shows that the Ni3Al-based high-entropy aluminide ingot prepared in this embodiment consists of an ordered L12 phase and a disordered FCC phase; combined with Figure 2a and Figure 2bAnalysis revealed that its solidification structure is dendritic, with the dendrite edges consisting of large micron-sized L12 phases and an outer layer of nano-layered FCC phases. The interior of the dendrites consists of finely and uniformly distributed nano-sized spherical L12 phases and a network of nano-sized FCC phases. The volume fraction of the L12 main phase exceeds 80%, indicating that Ni3Al-based high-entropy aluminides were successfully prepared.

[0149] Combination Figure 3 It can be seen that the density of the Ni3Al-based high-entropy aluminide ingot prepared in this embodiment is 8.03 g / cm³. 3 Yield strength greater than 620 MPa, tensile strength greater than 1220 MPa, yield strength ratio of 0.51, elongation greater than 35%, and strength-ductility product greater than 420 MPa·; at 800℃, yield strength greater than 560 MPa, tensile strength greater than 560 MPa, yield strength ratio of 1, elongation greater than 1%, and strength-ductility product greater than 5.6 MPa·.

[0150] Example 2

[0151] A Ni3Al-based high-entropy aluminide that satisfies the parameter criteria has the following composition by atomic percentage: Ni 40 Co 35 Fe4Al 11 Cr4Ti 3.5 Ta 1.5 Nb1-B 0.1 The total atomic content of elements Ni, Co, and Fe is 79%.

[0152] The preparation method of the Ni3Al-based high-entropy aluminide with the aforementioned composition is as follows:

[0153] S1. Conversion of alloy element content: Convert the atomic percentage of alloy elements in the above Ni3Al-based high-entropy aluminides into mass percentage to obtain the mass percentage of alloy element content.

[0154] S2. Weighing of raw materials corresponding to alloying elements: Calculate the required content of each element based on the total weight of the alloy ingot being 50g. Weigh the alloying elements of S1 according to their mass percentage. The elements Ni, Co, Fe, Al, Cr, Ti, Ta, Nb and B are all in bulk with a purity of 99.9 wt.% or higher to obtain the raw materials corresponding to the alloying elements.

[0155] S3, Pre-treatment and cleaning of raw materials corresponding to alloy elements: The raw materials corresponding to the alloy elements in S2 are pre-treated and cleaned. The pre-treatment and cleaning is carried out by grinding with a grinding wheel to remove surface oxide scale or impurities. Then, they are cut into small pieces with shearing pliers, and then cleaned in anhydrous ethanol and dried to obtain pre-treated raw materials.

[0156] S4. Placement of pretreated raw materials in a vacuum arc melting furnace: The pretreated raw materials of S3 are melted in a vacuum arc melting furnace. The pretreated raw materials are placed in the vacuum arc melting furnace in the following order: the weighed volatile and lightweight elements such as B, Al, and Cr are placed at the bottom of the crucible to prevent splashing and reduce volatilization. Other metal raw materials are placed in the copper crucible in order of melting point from low to high, so as to ensure that the high melting point elements are in direct contact with the arc and fully melted at high temperature. The titanium ingot is placed in the middle crucible.

[0157] S5. Multiple Melting and Casting: The pre-treated raw material placed in S4 is melted and cast multiple times. To ensure that the elements are evenly distributed in the resulting button ingot, each alloy ingot is melted 6-8 times. After each melting and waiting for the button ingot to cool, it is flipped to the other side using a flipping spatula before the next melting. Finally, the alloy ingot is remelted and cast into a 10mm×10mm×60mm copper mold. After complete cooling, it is taken out of the furnace to obtain an ingot of Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy.

[0158] The ingot of Ni3Al-based high-entropy aluminide prepared in this embodiment consists of an ordered L12 phase and a disordered FCC phase. Its solidification structure is dendritic, with the dendrite edges consisting of bulk micron-sized L12 phase and an outer layer of nano-sized FCC phase. The interior of the dendrite consists of fine and uniformly distributed nano-sized spherical L12 phase and a network of nano-sized FCC phase. The volume fraction of the main L12 phase exceeds 80%, indicating that Ni3Al-based high-entropy aluminide was successfully prepared.

[0159] The Ni3Al-based high-entropy aluminide ingot prepared in this embodiment has a density of 8.05 g / cm³. 3 Yield strength greater than 550 MPa, tensile strength greater than 1150 MPa, yield strength ratio of 0.48, elongation greater than 25%, and strength-ductility product greater than 280 MPa·%; at 800℃, yield strength greater than 550 MPa, tensile strength greater than 550 MPa, yield strength ratio of 1, elongation greater than 1%, and strength-ductility product greater than 5.5 MPa·%.

[0160] Example 3

[0161] A Ni3Al-based high-entropy aluminide that satisfies the parameter criteria has the following composition by atomic percentage: Ni 42 Co 35 Al 11 Cr4Ti4Ta1Nb1W1Mo1-B 0.1 The total atomic content of elements Ni and Co is 77%.

[0162] The preparation method of the Ni3Al-based high-entropy aluminide with the aforementioned composition is as follows:

[0163] S1. Conversion of alloy element content: Convert the atomic percentage of alloy elements in the above Ni3Al-based high-entropy aluminides into mass percentage to obtain the mass percentage of alloy element content.

[0164] S2. Weighing of raw materials corresponding to alloying elements: Calculate the required content of each element based on the total weight of the alloy ingot being 50g. Weigh the alloying elements of S1 according to their mass percentage. The elements Ni, Co, Al, Cr, Ti, Ta, Nb, W, Mo and B are all in bulk with a purity of 99.9 wt.% or higher to obtain the raw materials corresponding to the alloying elements.

[0165] S3, Pre-treatment and cleaning of raw materials corresponding to alloy elements: The raw materials corresponding to the alloy elements in S2 are pre-treated and cleaned. The pre-treatment and cleaning is carried out by grinding with a grinding wheel to remove surface oxide scale or impurities. Then, they are cut into small pieces with shearing pliers, and then cleaned in anhydrous ethanol and dried to obtain pre-treated raw materials.

[0166] S4. Placement of pretreated raw materials in a vacuum arc melting furnace: The pretreated raw materials of S3 are melted in a vacuum arc melting furnace. The pretreated raw materials are placed in the vacuum arc melting furnace in the following order: the weighed volatile and lightweight elements such as B, Al, and Cr are placed at the bottom of the crucible to prevent splashing and reduce volatilization. Other metal raw materials are placed in the copper crucible in order of melting point from low to high, so as to ensure that the high melting point elements are in direct contact with the arc and fully melted at high temperature. The titanium ingot is placed in the middle crucible.

[0167] S5. Multiple Melting and Casting: The pre-treated raw material placed in S4 is melted and cast multiple times. To ensure that the elements are evenly distributed in the resulting button ingot, each alloy ingot is melted 6-8 times. After each melting and waiting for the button ingot to cool, it is flipped to the other side using a flipping spatula before the next melting. Finally, the alloy ingot is remelted and cast into a 10mm×10mm×60mm copper mold. After complete cooling, it is taken out of the furnace to obtain an ingot of Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy.

[0168] The ingot of Ni3Al-based high-entropy aluminide prepared in this embodiment consists of ordered L12 phase and disordered FCC phase; its solidification structure is typical dendrite, with the dendrite edges consisting of bulk micron-sized L12 phase and an outer layer of nano-layered FCC phase, and the dendrite interior consisting of fine and uniformly distributed nano-sized spherical L12 phase and network-like nano-sized FCC phase. The volume fraction of the main L12 phase exceeds 80%, indicating that Ni3Al-based high-entropy aluminide was successfully prepared.

[0169] The Ni3Al-based high-entropy aluminide ingot prepared in this embodiment has a density of 8.15 g / cm³. 3Yield strength greater than 630 MPa, tensile strength greater than 1190 MPa, yield strength ratio of 0.53, elongation greater than 35%, and strength-ductility product greater than 410 MPa·%; at 800℃, yield strength greater than 600 MPa, tensile strength greater than 600 MPa, yield strength ratio of 1, elongation greater than 1%, and strength-ductility product greater than 6 MPa·%.

[0170] Example 4

[0171] A Ni3Al-based high-entropy aluminide that satisfies the parameter criteria has the following composition by atomic percentage: Ni 38.5 Co 38.5 Al 11.5 Cr 4.5 Ti5Ta2-B 0.1 C 0.2 The total atomic content of elements Ni and Co is 77%.

[0172] The preparation method of the Ni3Al-based high-entropy aluminide with the aforementioned composition is as follows:

[0173] S1. Conversion of alloy element content: Convert the atomic percentage of alloy elements in the above Ni3Al-based high-entropy aluminides into mass percentage to obtain the mass percentage of alloy element content.

[0174] S2. Weighing of raw materials corresponding to alloying elements: Calculate the required content of each element based on the total weight of the alloy ingot being 50g. Weigh the alloying elements according to the mass percentage of S1. Elements Ni, Co, Al, Cr, Ti, Ta, B, and C are all in bulk form with a purity of 99.9 wt.% or higher to obtain the raw materials corresponding to the alloying elements.

[0175] S3, Pre-treatment and cleaning of raw materials corresponding to alloy elements: The raw materials corresponding to the alloy elements in S2 are pre-treated and cleaned. The pre-treatment and cleaning is carried out by grinding with a grinding wheel to remove surface oxide scale or impurities. Then, they are cut into small pieces with shearing pliers, and then cleaned in anhydrous ethanol and dried to obtain pre-treated raw materials.

[0176] S4. Placement of pretreated raw materials in a vacuum arc melting furnace: The pretreated raw materials of S3 are melted in a vacuum arc melting furnace. The pretreated raw materials are placed in the vacuum arc melting furnace in the following order: the weighed volatile and lightweight elements such as B, Al, and Cr are placed at the bottom of the crucible to prevent splashing and reduce volatilization. Other metal raw materials are placed in the copper crucible in order of melting point from low to high, so as to ensure that the high melting point elements are in direct contact with the arc and fully melted at high temperature. The titanium ingot is placed in the middle crucible.

[0177] S5. Multiple melting and suction casting: The pre-treated raw materials placed in S4 are melted and then suction cast multiple times. In order to ensure that the elements are evenly distributed in the obtained button ingot, each alloy ingot is melted 6-8 times. After each melting is completed and the button ingot is cooled, it is flipped to the other side with a flipping shovel before the next melting. Finally, the alloy ingot is remelted and suction cast into a 10mm×10mm×60mm copper mold. After complete cooling, it is taken out of the furnace to obtain an ingot of Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy.

[0178] S6. Annealing treatment: The ingot of Ni3Al-based high-entropy aluminate with excellent strong plasticity synergy in S5 is subjected to homogenization annealing treatment. The homogenization annealing treatment temperature is 1230℃ and the time is 1h. After that, it is cooled to room temperature by oil cooling or air cooling to obtain annealed Ni3Al-based high-entropy aluminate ingot.

[0179] S7. Cold deformation treatment: The S6 annealed Ni3Al-based high-entropy aluminide ingot is subjected to cold deformation treatment such as rolling, drawing, forging or extrusion. The total deformation amount of the cold deformation treatment is 68%, and cold-deformed Ni3Al-based high-entropy aluminide material is obtained.

[0180] S8. Recrystallization Annealing: The S7 cold-deformed Ni3Al-based high-entropy aluminide material is subjected to recrystallization annealing at a temperature of 1200℃ for 1-1.5 min. The cooling method is oil cooling or air cooling. Finally, a partially recrystallized Ni3Al-based high-entropy aluminide cold-deformed material is obtained.

[0181] The cold-deformed Ni3Al-based high-entropy aluminide material prepared in this embodiment is mainly composed of ordered L12 phase and disordered FCC phase, containing a small amount (<5 vol%) of MC-type carbides. In the recrystallized region, the L12 phase has two sizes: micron-sized rod-shaped particles and nano-sized spherical particles, which are uniformly distributed. The outer layer of the L12 phase is coated with a nano-sized network FCC phase. In the non-recrystallized region, the L12 phase consists of nano-sized spherical particles with a size of 150-200 nm, which are uniformly distributed. The outer layer of the L12 phase is coated with a nano-sized network FCC phase. The total volume fraction of the ordered L12 phase in the alloy exceeds 80%.

[0182] The density of the cold-deformed Ni3Al-based high-entropy aluminide material prepared in this embodiment is 8.03 g / cm³. 3 Yield strength greater than 950 MPa, tensile strength greater than 1550 MPa, yield strength ratio of 0.61, elongation greater than 20%, and strength-ductility product greater than 310 MPa·; at a high temperature of 800℃, yield strength greater than 740 MPa, tensile strength greater than 840 MPa, yield strength ratio of 0.88, elongation greater than 1.6%, and strength-ductility product greater than 13 MPa·.

[0183] Example 5

[0184] A Ni3Al-based high-entropy aluminide that satisfies the parameter criteria has the following composition by atomic percentage: Ni 45 Co 25 Fe 10 Al 10 Ti 8.5 Nb 1.5 -B 0.5 The total atomic content of the elements Ni, Co and Fe is 80%.

[0185] The preparation method of the Ni3Al-based high-entropy aluminide with the aforementioned composition is as follows:

[0186] S1. Conversion of alloy element content: Convert the atomic percentage of alloy elements in the above Ni3Al-based high-entropy aluminides into mass percentage to obtain the mass percentage of alloy element content.

[0187] S2. Weighing of raw materials corresponding to alloying elements: Calculate the required content of each element based on the total weight of the alloy ingot being 50g. Weigh the alloying elements according to the mass percentage of S1. Elements Ni, Co, Fe, Al, Ti, Nb and B are all in bulk with a purity of 99.9 wt.% or higher to obtain the raw materials corresponding to the alloying elements.

[0188] S3, Pre-treatment and cleaning of raw materials corresponding to alloy elements: The raw materials corresponding to the alloy elements in S2 are pre-treated and cleaned. The pre-treatment and cleaning is carried out by grinding with a grinding wheel to remove surface oxide scale or impurities. Then, they are cut into small pieces with shearing pliers, and then cleaned in anhydrous ethanol and dried to obtain pre-treated raw materials.

[0189] S4. Placement of pretreated raw materials in a vacuum arc melting furnace: The pretreated raw materials of S3 are melted in a vacuum arc melting furnace. The pretreated raw materials are placed in the vacuum arc melting furnace in the following order: the weighed B and Al volatile and light elements are placed at the bottom of the crucible to prevent splashing and reduce volatilization. Other metal raw materials are placed in the copper crucible in order of melting point from low to high, so as to ensure that the high melting point elements are in direct contact with the arc and fully melted at high temperature. The titanium ingot is placed in the middle crucible.

[0190] S5. Multiple melting and suction casting: The pre-treated raw materials placed in S4 are melted and then suction cast multiple times. In order to ensure that the elements are evenly distributed in the obtained button ingot, each alloy ingot is melted 6-8 times. After each melting is completed and the button ingot is cooled, it is flipped to the other side with a flipping shovel before the next melting. Finally, the alloy ingot is remelted and suction cast into a 10mm×10mm×60mm copper mold. After complete cooling, it is taken out of the furnace to obtain an ingot of Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy.

[0191] S6. Annealing treatment: The ingot of Ni3Al-based high-entropy aluminate with excellent strong plasticity synergy in S5 is subjected to homogenization annealing treatment. The homogenization annealing treatment temperature is 1150℃ and the time is 2h. After that, it is cooled to room temperature by oil cooling or air cooling to obtain annealed Ni3Al-based high-entropy aluminate ingot.

[0192] S7. Cold deformation treatment: The S6 annealed Ni3Al-based high-entropy aluminide ingot is subjected to cold deformation treatment such as rolling, drawing, forging or extrusion. The total deformation amount of the cold deformation treatment is 62%, and cold-deformed Ni3Al-based high-entropy aluminide material is obtained.

[0193] S8. Recrystallization Annealing Treatment: The S7 cold-deformed Ni3Al-based high-entropy aluminide material is subjected to recrystallization annealing treatment at a temperature of 1100℃ for 30 minutes. The cooling method is oil cooling or air cooling. Finally, a fully recrystallized Ni3Al-based high-entropy aluminide cold-deformed material is obtained.

[0194] The cold-deformed Ni3Al-based high-entropy aluminide material prepared in this embodiment consists of an ordered L12 phase and a disordered FCC phase. The L12 phase has two sizes: micron-sized irregular blocky particles and nano-sized spherical particles. The L12 phase is uniformly distributed. The outer layer of the L12 phase is coated with a nano-sized network FCC phase, and the volume fraction of the L12 main phase exceeds 70%.

[0195] The density of the cold-deformed Ni3Al-based high-entropy aluminide material prepared in this embodiment is 7.78 g / cm³. 3 The room temperature yield strength is greater than 830 MPa, the tensile strength is greater than 1330 MPa, the yield strength ratio is 0.62, the elongation is greater than 20%, and the strength-ductility product is greater than 265 MPa.

[0196] Comparative Example 1

[0197] Polycrystalline Ni3Al-based aluminum compound IC221M was prepared using a vacuum arc furnace. The alloy composition, by mass percentage, was 79.9Ni-8.1Al-7.6Cr-1.5Mo-1.72Zr-0.04C-0.04Si-0.07Fe. The cast alloy mainly consisted of ordered L12 phase, disordered FCC phase, and FCC-Ni5Zr eutectic, with the L12 phase accounting for over 80% by volume. Without heat treatment, the alloy exhibited a room temperature yield strength of 553 MPa, a tensile strength of 775 MPa, and an elongation of 11.6%. After solution treatment at 1100℃ for 20 h, the alloy showed a room temperature yield strength of 457 MPa, a tensile strength of 574 MPa, and an elongation of 6%.

[0198] Comparative Example 2

[0199] Polycrystalline Ni3Al-based aluminides were prepared using a vacuum induction melting process. The alloy composition, by mass percentage, was 0.18C-9.82Al-6.26Co-5.58Cr-2.52Mo-1.88W-1.06Ti-0.79Zr-0.012B-71.9Ni. The cast alloy was held at 1270℃ for 5 hours, followed by air cooling. It mainly consisted of an ordered L12 phase and a disordered FCC phase. The L12 phase exhibited both micron-sized island-like particles and nano-sized spherical particles, with a volume fraction exceeding 80%. The room temperature yield strength, tensile strength, and elongation of this alloy were 488 MPa, 686 MPa, and 5.2%, respectively.

[0200] Comparing Comparative Examples 1-2 and Examples 1-6 reveals the following:

[0201] The design and preparation method of Ni3Al-based high-entropy aluminides provided by this invention has the following beneficial effects:

[0202] 1) The formation of Ni3Al-based high-entropy aluminides can be predicted by using a phase formation criterion based on a pseudo-binary sublattice model, reducing experimental trial and error costs and enabling controllable design of Ni3Al-based high-entropy aluminides.

[0203] 2) The room temperature yield strength of this Ni3Al-based high-entropy aluminate is greater than 620 MPa, the tensile strength is greater than 1190 MPa, and the elongation is greater than 25%. Compared with existing Ni3Al-based aluminates, this Ni3Al-based high-entropy aluminate has superior comprehensive mechanical properties.

[0204] 3) This invention successfully prepared Ni3Al-based high-entropy aluminides through composition design, smelting and casting, and cold deformation treatment. The aluminides have excellent performance, simple process, and low cost, making them very suitable for large-scale industrial production.

[0205] The present invention proposes a Ni3Al-based high-entropy aluminum compound with excellent synergistic properties of strength and plasticity, and its preparation method, which can solve the technical problems of the inability to simultaneously achieve strength and plasticity in the prior art.

[0206] This invention uses phase formation criteria (enthalpy-entropy ratio, atomic size difference, electronegativity difference, valence electron concentration deviation, and total valence electron concentration) based on a pseudo-binary sublattice model to predict the formation of Ni3Al-based high-entropy aluminum compounds, reducing experimental trial-and-error costs and providing reference and guidance for the design and development of Ni3Al-based high-entropy aluminum compounds.

[0207] The Ni3Al-based high-entropy aluminides of this invention have a yield strength greater than 620 MPa and a tensile strength exceeding 1190 MPa, while maintaining a large elongation (>25%). Compared with other Ni3Al alloys and Ni3Al-based intermetallic compound alloys with simple compositions, they have superior comprehensive mechanical properties.

[0208] The preparation process of this invention is simple, highly operable, low in energy consumption and cost, suitable for industrial production, and has broad application prospects in aerospace and other fields.

[0209] In summary, compared with traditional methods for preparing Ni3Al-based aluminum compounds, the method of this invention selects the composition content of Ni3Al-based high-entropy aluminum compounds by using a phase formation criterion based on a pseudo-binary sublattice model, thereby synergistically improving the strength and plasticity of Ni3Al-based aluminum compounds that meet the criterion. This method for preparing Ni3Al-based aluminum compounds that meet the criterion is simple to operate, environmentally friendly, low in cost, short in process, and highly efficient, which is conducive to large-scale industrial production and promotion.

[0210] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0211] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be a single item or multiple items.

[0212] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply 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.

[0213] 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 variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A design method for Ni3Al-based high-entropy aluminides with excellent strong plasticity synergy, characterized in that, The design method for Ni3Al-based high-entropy aluminides with excellent strong plasticity synergy needs to meet certain parameter criteria, including the enthalpy-entropy ratio based on a pseudo-binary sublattice model. Atomic size differences: , Electronegativity differences: , Valence electron concentration deviation: , Total valence electron concentration: ; The enthalpy-entropy ratio η based on the pseudo-binary sublattice model is expressed as: (1)； Among them, melting temperature T m It is the average melting point of all major elements; enthalpy of mixing and mixed entropy Represented as: (2)； (3)； in, This represents the mole fraction of element type i in the entire alloy system within sublattice A. This represents the mole fraction of element type j in the B sublattice relative to the entire alloy system. Let represent the enthalpy of mixing of a binary alloy with equal atomic ratios composed of the i-th and j-th elements in the A and B sublattices; R is the ideal gas constant 8.314 J. (mol K) -1 , Represents the number of sites on sublattice A. Represents the number of sites on the B sublattice. This represents the mole fraction of component i in sublattice A. This represents the mole fraction of component j in sublattice B relative to its respective sublattice. The atomic size differences mentioned are divided into atomic size differences of components on the same sublattice. Atomic size differences between components in different sublattices ; The electronegativity difference is divided into electronegativity differences of components on the same sublattice. Electronegativity differences between components of different sublattices ; The valence electron concentration deviation is divided into the valence electron concentration deviation of components on the same sublattice. Valence electron concentration deviation of components between different sublattices ; Total valence electron concentration of alloy Represented as: (10)； in, This represents the mole fraction of element type i in the entire alloy system within sublattice A. This represents the mole fraction of element type j in the B sublattice of the entire alloy system. Let VEC represent the value of the i-th element in the sub-lattice A. Let VEC represent the value of the j-th element in the B sub-lattice.

2. The design method for Ni3Al-based high-entropy aluminides with excellent strong plasticity synergy according to claim 1, characterized in that, Atomic size difference of components on the same sublattice Represented as: (4)； Atomic size differences of components between different sublattices Represented as: (5)； in, This represents the mole fraction of component i in sublattice A. This represents the mole fraction of component j in sublattice B relative to its respective sublattice. r i Let r represent the atomic radius of the i-th element in sublattice A. j Let represent the atomic radius of the j-th element in the B sublattice; Represents the number of sites on sublattice A. Represents the number of sites on the B sublattice. This represents the average atomic radius on sublattice A. This represents the average atomic radius on the B sublattice, and , .

3. The design method for Ni3Al-based high-entropy aluminides with excellent strong plasticity synergy according to claim 1, characterized in that, Electronegativity differences of components on the same sublattice Represented as: (6)； Electronegativity differences among components of different sublattices Represented as; (7)； in, This represents the mole fraction of component i in sublattice A. This represents the mole fraction of component j in sublattice B relative to its respective sublattice. This represents the mole fraction of element type i in the entire alloy system within sublattice A. This represents the mole fraction of element type j in the B sublattice relative to the entire alloy system. Represents the number of sites on sublattice A. Represents the number of sites on the B sublattice. Denotes the Pauling electronegativity of the i-th element in the A sublattice. Let represent the Pauling electronegativity of the j-th element in the B sublattice; This represents the average Pauling electronegativity on sublattice A. This represents the average Pauling electronegativity on the B sublattice, and , .

4. The design method for Ni3Al-based high-entropy aluminides with excellent strong plasticity synergy according to claim 1, characterized in that, Valence electron concentration deviation of components on the same sublattice Represented as: (8)； Valence electron concentration deviation of components between different sublattices Represented as: (9)； in, This represents the mole fraction of element type i in the entire alloy system within sublattice A. This represents the mole fraction of element type j in the B sublattice of the entire alloy system. This represents the mole fraction of component i in sublattice A. This represents the mole fraction of component j in sublattice B relative to its respective sublattice. Represents the number of sites on sublattice A. Represents the number of sites on the B sublattice. Let VEC represent the value of the i-th element in the sub-lattice A. Represents the VEC of the j-th element in the B sub-lattice; Denotes the average VEC on sublattice A. Let VEC represent the average VEC over the B sublattice, and , .

5. The design method for Ni3Al-based high-entropy aluminides with excellent strong plasticity synergy according to claim 1, characterized in that, The composition of Ni3Al-based high-entropy aluminides satisfying the aforementioned parameter criteria, by atomic percentage, is as follows: Ni 25-55 at.%, Co 20-50 at.%, Fe 0-10 at.%, Al 5-20 at.%, Cr 4-15 at.%, Ti 2-15 at.%, Ta 0-5 at.%, Nb 0-5 at.%, W 0-5 at.%, Mo 0-5 at.%, V 0-5 at.%, B 0.02-1 at.%, C 0-1 at.%; the total atomic content of elements Ni, Co, and Fe is 72-82 at.%; the sum of the atomic percentages of all components is 100%.

6. A method for preparing Ni3Al-based high-entropy aluminides with excellent strong plasticity synergy based on the design method of claim 5, characterized in that, The preparation method of the Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy according to the design method is as follows: S1. Conversion of alloy element content: Convert the atomic percentage of alloy elements in the above Ni3Al-based high-entropy aluminides into mass percentage to obtain the mass percentage of alloy element content. S2. Weighing of raw materials corresponding to alloying elements: Weigh the alloying elements of S1 according to their mass percentage to obtain the raw materials corresponding to the alloying elements. S3, Pretreatment and cleaning of raw materials corresponding to alloying elements: Pretreatment and cleaning of raw materials corresponding to alloying elements in S2 to obtain pretreated raw materials; S4. Placement of pre-treated raw materials in a vacuum arc melting furnace: The pre-treated raw materials of S3 are melted in a vacuum arc melting furnace, and the pre-treated raw materials are placed in the vacuum arc melting furnace in sequence. S5. Multiple melting and suction casting: The pre-treated raw material placed in S4 is melted and then suction cast multiple times. After complete cooling, it is taken out of the furnace to obtain an ingot of Ni3Al-based high-entropy aluminate with excellent strong plasticity synergy.

7. The method for preparing the Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy according to claim 6, characterized in that, The method for preparing the Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy further includes the following steps: S6. Annealing treatment: The ingot of Ni3Al-based high-entropy aluminide with excellent strong plasticity synergy in S5 is subjected to homogenization annealing treatment, and then cooled to room temperature to obtain annealed Ni3Al-based high-entropy aluminide ingot. S7. Cold deformation treatment: The S6 annealed Ni3Al-based high-entropy aluminide ingot is subjected to cold deformation treatment including rolling, drawing, forging or extrusion to obtain cold-deformed Ni3Al-based high-entropy aluminide material. S8. Recrystallization Annealing Treatment: The cold-deformed Ni3Al-based high-entropy aluminide material of S7 is subjected to recrystallization annealing treatment to finally obtain partially or completely recrystallized Ni3Al-based high-entropy aluminide cold-deformed material.

8. The method for preparing Ni3Al-based high-entropy aluminides with excellent synergistic plasticity according to claim 7, characterized in that, The total deformation of S7 after cold deformation treatment is 40-90%.

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