Ni-based high-entropy alloy and preparation method thereof
Through segmented heat treatment, the diffusion of atoms and grain growth in Ni-based high-entropy alloys are suppressed, which solves the problem of insufficient high-temperature strength and stability of Ni-based high-entropy alloys, and achieves the improvement of the high-temperature mechanical properties of the alloy.
Patent Information
- Application Number
- CN202510315594.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-18
- Publication Date
- 2025-06-13
AI Technical Summary
The prior art has shortcomings in improving the high temperature strength and stability of Ni-based high-entropy alloys, resulting in a degradation of the overall performance of the alloy.
The segmented heat treatment method is adopted, including a heating section, aging section with set temperature and pressure, and a cooling section, to reduce the diffusion speed of atoms in Ni-based high-entropy alloy, inhibit the rapid growth of grains and reduce the degree of recrystallization, thereby increasing the recrystallization temperature of the alloy.
Through this method, the high temperature strength and stability of Ni-based high-entropy alloy are significantly improved, the recrystallization process is delayed, and the mechanical properties of the alloy in high-temperature environment are improved.
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Figure CN120138468A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of high-entropy alloy preparation, and particularly relates to a Ni-based high-entropy alloy and a preparation method thereof. Background Art
[0002] High-entropy alloys are the products of a novel alloy design concept. The alloy composition is a mixture of four or more elements in equimolar or near-equimolar ratios, and a stable simple structure is formed due to the high-entropy effect. High-entropy alloys have four major effects: the high-entropy effect in thermodynamics, the sluggish diffusion effect in kinetics, the severe lattice distortion effect, and the cocktail effect in performance. These effects endow high-entropy alloys with excellent properties such as high hardness, high strength, high fracture toughness, high wear and corrosion resistance, and radiation resistance. At the same time, they also ensure that high-entropy alloys can meet a wide range of application scenarios by adjusting the alloy composition. In recent years, Ni-based high-entropy alloys with high-temperature stability and coordinated high plasticity have received extensive attention in the fields of aviation, aerospace, and navigation.
[0003] Currently, when high-entropy alloys increase the solubility of precipitation phases by increasing the solution temperature and prolonging the solution time, the comprehensive properties of the alloys will decline. Summary of the Invention
[0004] This application provides a Ni-based high-entropy alloy and a preparation method thereof to solve the following technical problems: how to improve the high-temperature strength and stability of Ni-based high-entropy alloys.
[0005] In a first aspect, this application provides a preparation method of a Ni-based high-entropy alloy, and the method includes:
[0006] Obtaining a cold hard plate of a Ni-based high-entropy alloy with a set chemical composition, and the set chemical composition includes: Ni, Co, Cr, and Fe;
[0007] Performing segmented heat treatment on the cold hard plate of the Ni-based high-entropy alloy to reduce the diffusion rate of atoms in the cold hard plate of the Ni-based high-entropy alloy, and obtaining a Ni-based high-entropy alloy; wherein, the segmented heat treatment includes: heat treatment of a heating section, an aging section with a set temperature and a set pressure, and a cooling section arranged in sequence.
[0008] Optionally, the set pressure is 3 GPa to 5 GPa; and / or,
[0009] The set temperature is 900 °C to 1100 °C.
[0010] Optionally, the time of the aging section is 1 h to 2 h.
[0011] Optionally, in terms of atomic percentage, the total atoms of Ni, Co, Cr, and Fe are 90% to 92%.
[0012] Optionally, the set chemical composition further includes: Al and / or Ti.
[0013] Optionally, the heating rate in the heating stage is 120°C / min to 150°C / min; and / or,
[0014] the cooling rate in the cooling stage is 150°C / min to 200°C / min.
[0015] Optionally, obtaining the Ni-based high-entropy alloy cold hard plate with a set chemical composition includes:
[0016] performing a first solution treatment on the Ni-based high-entropy alloy ingot with a set chemical composition;
[0017] successively performing a first rolling, a second solution treatment, and a second rolling on the Ni-based high-entropy alloy ingot after the first solution treatment to obtain a Ni-based high-entropy alloy cold hard plate with a set chemical composition.
[0018] Optionally, the holding temperatures of the first solution treatment and the second solution treatment are 1150°C to 1200°C respectively.
[0019] Optionally, the second rolling is multi-pass rolling, and the process parameters of the multi-pass rolling include: the rolling speed is 100 mm / s to 120 mm / s, and the reduction per pass is 0.1 mm to 0.5 mm.
[0020] In a second aspect, the present application provides a Ni-based high-entropy alloy, which is prepared by the method according to any one of the first aspect.
[0021] The above technical solutions provided by the embodiments of the present application have the following advantages compared with the prior art:
[0022] The preparation method of the Ni-based high-entropy alloy provided by the embodiment of the present application includes: obtaining a Ni-based high-entropy alloy cold hard plate with a set chemical composition, where the set chemical composition includes: Ni, Co, Cr, and Fe; performing segmented heat treatment on the Ni-based high-entropy alloy cold hard plate to reduce the diffusion rate of atoms in the Ni-based high-entropy alloy cold hard plate to obtain a Ni-based high-entropy alloy; wherein, the segmented heat treatment includes: a heat treatment of a heating stage, an aging stage with a set temperature and a set pressure, and a cooling stage arranged in sequence. The Ni-based high-entropy alloy cold hard plate is subjected to aging treatment in the aging stage with a set temperature and a set pressure, which can inhibit the movement speed of atoms in the Ni-based high-entropy alloy cold hard plate during the aging treatment, thereby inhibiting the rapid growth of grains and reducing the recrystallization degree of the Ni-based high-entropy alloy cold hard plate, effectively increasing the recrystallization temperature of the Ni-based high-entropy alloy, and further improving the high-temperature strength and stability of the Ni-based high-entropy alloy. Brief Description of the Drawings
[0023] The drawings herein are incorporated into and form a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.
[0024] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0025] Figure 1 Schematic flow diagram of a preparation method of a Ni-based high-entropy alloy provided by an embodiment of the present application;
[0026] Figure 2 Metallographic diagram of a Ni-based high-entropy alloy provided by Embodiment 1 of the present application;
[0027] Figure 3 Metallographic diagram of a Ni-based high-entropy alloy provided by Embodiment 2 of the present application;
[0028] Figure 4 Metallographic diagram of a Ni-based high-entropy alloy provided by Embodiment 3 of the present application;
[0029] Figure 5 Metallographic diagram of a Ni-based high-entropy alloy provided by Comparative Example 1 of the present application;
[0030] Figure 6 Metallographic diagram of a Ni-based high-entropy alloy provided by Comparative Example 2 of the present application;
[0031] Figure 7 Metallographic diagram of a Ni-based high-entropy alloy provided by Comparative Example 3 of the present application;
[0032] Figure 8 Curved graph of stress-strain comparison of a Ni-based high-entropy alloy provided by Embodiment 3 and Comparative Example 3 of the present application. Detailed Description of the Embodiments
[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.
[0034] The various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present application; therefore, it should be considered that the description of the range has specifically disclosed all possible sub-ranges and individual values within the range. For example, it should be considered that the description of the range from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, which applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.
[0035] In the present application, unless otherwise stated, the orientation terms such as "upper" and "lower" specifically refer to the drawing directions in the figures. Additionally, in the description of the specification of the present application, the terms "including", "comprising", etc. mean "including but not limited to". In this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this text, "and / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Where A and B can be singular or plural.
[0036] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present application can be obtained through market purchases or can be prepared by existing methods.
[0037] In a first aspect, the present application provides a method for preparing a Ni-based high-entropy alloy. Figure 1 is a schematic flow diagram of a method for preparing a Ni-based high-entropy alloy provided by an embodiment of the present application; please refer to Figure 1 , the method includes:
[0038] S1. Obtain a cold hard plate of a Ni-based high-entropy alloy with a set chemical composition, and the set chemical composition includes: Ni, Co, Cr, and Fe;
[0039] In some embodiments, in terms of atomic percentage, the total atomic sum of Ni, Co, Cr, and Fe is 90% - 92%.
[0040] In some embodiments, the set chemical composition further includes: Al and / or Ti
[0041] Ni-based high-entropy alloys are a new type of alloy material composed of multiple elements (usually four or more) combined in a near-equiatomic ratio or a specific ratio. Due to their unique composition and microstructure, they exhibit excellent physical, chemical, and mechanical properties. In the embodiments of this application, the chemical composition of the above Ni-based high-entropy alloy cold hard plate includes: Ni, Co, Cr, Fe, and Al and / or Ti. Al and Ti have large atomic sizes and can relatively inhibit the diffusion of other atoms, thereby increasing the recrystallization temperature of the alloy. Ni, Co, Cr, Fe, and Al and / or Ti can synergistically improve the mechanical properties of the alloy. The total atomic sum of Ni, Co, Cr, and Fe can be 91% - 93%, so the total atomic sum of Al and / or Ti can be 7% - 9%, which is beneficial to the formation of the new phase L1 2 --(Ni 3 (Al / Ti)), which has a positive effect on improving the comprehensive properties of the alloy. Exemplarily, the total atomic sum of Ni, Co, Cr, and Fe can be 91%, 91.5%, 92%, 92.5%, 93%, etc.
[0042] In some embodiments, obtaining the Ni-based high-entropy alloy cold hard plate with a set chemical composition includes:
[0043] Performing a first solution treatment on the Ni-based high-entropy alloy ingot with a set chemical composition;
[0044] Sequentially performing a first rolling, a second solution treatment, and a second rolling on the Ni-based high-entropy alloy ingot after the first solution treatment to obtain a Ni-based high-entropy alloy cold hard plate with a set chemical composition.
[0045] In some embodiments, the holding temperatures of the first solution treatment and the second solution treatment are 1150°C - 1200°C respectively.
[0046] In the embodiments of this application, solution treatment is a heat treatment process for metal materials. Through solution treatment, various phases in the alloy can be fully dissolved, thereby improving the mechanical properties of the alloy. During the processing of metal materials, such as casting, forging, and welding, residual stresses will be generated. Solution treatment can homogenize the internal organizational structure of the metal, effectively eliminate these residual stresses, and reduce the possibility of deformation or cracking of the parts due to stress concentration during use. Solution treatment can improve the cutting and cold working properties of metal materials. Therefore, after solution treatment, the hardness and strength distribution of the metal are more uniform, making it easier to obtain good surface quality and dimensional accuracy during processing.
[0047] The Ni-based high-entropy alloy ingot is subjected to a first solution treatment. The holding temperature of the first solution treatment can be 1150°C to 1200°C, which can make the alloying elements in the Ni-based high-entropy alloy ingot in a state of complete mutual solubility, forming a uniform solid solution. And subsequently, the Ni-based high-entropy alloy ingot after the first rolling is subjected to a second solution treatment. The holding temperature of the second solution treatment can be 1150°C to 1200°C. The holding temperature of the first solution treatment and the holding temperature of the second solution treatment can be 1150°C to 1200°C, which can eliminate the work hardening phenomenon generated during the first rolling process and make the alloying elements in the Ni-based high-entropy alloy ingot after the first rolling in a state of complete mutual solubility, thereby providing conditions for the subsequent second rolling. Exemplarily, the holding temperatures of the first solution treatment and the second solution treatment can both be 1150°C, 1160°C, 1170°C, 1180°C, 1190°C, 1200°C, etc.
[0048] Exemplarily, the above-mentioned first solution treatment includes: placing the alloy ingot in an air furnace at 1150°C to 1200°C and holding for 2 hours, and then taking it out and quenching it in water to room temperature.
[0049] In some embodiments, the second rolling is multi-pass rolling. The process parameters of the multi-pass rolling include: the rolling speed is 100 mm / s to 120 mm / s, and the reduction per pass is 0.1 mm to 0.5 mm.
[0050] In the embodiments of the present application, the second rolling can be multi-pass rolling. The process parameters of the multi-pass rolling include: the rolling speed can be 100 mm / s to 120 mm / s, and the reduction per pass can be 0.1 mm to 0.5 mm, which can achieve the deformation effect of the ingot and reduce the working efficiency, and avoid cracking of the ingot during the rolling process. Exemplarily, the rolling speed can be 100 mm / s, 105 mm / s, 110 mm / s, 115 mm / s, 120 mm / s, etc.; the reduction per pass can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, etc.
[0051] "Subjecting the Ni-based high-entropy alloy ingot after the first solution treatment to first rolling, second solution treatment, and second rolling in sequence to obtain a cold-rolled sheet of Ni-based high-entropy alloy" is the cold rolling process. Cold rolling is a rolling process carried out below the recrystallization temperature of the metallic material. During cold rolling, the metallic material is subjected to the pressure of the rolling rolls and undergoes plastic deformation, and the internal grain structure is elongated, broken, and refined, thereby increasing the strength and hardness of the metal and improving its surface quality and dimensional accuracy. Exemplarily, first roll the Ni-based high-entropy alloy ingot to a thickness of about 8 mm, and after solution treatment at a high temperature of 1150 °C to 1200 °C for 2 h; perform room-temperature rolling on a rolling mill at a speed of 100 mm / s to 120 mm / s, with a reduction per pass of 0.1 mm to 0.5 mm. After multiple passes of rolling, the thickness of the cold-rolled sheet of Ni-based high-entropy alloy becomes 1.6 mm, and the cold rolling reduction is 80%.
[0052] Exemplarily, the method for obtaining the Ni-based high-entropy alloy ingot includes: putting Ni, Co, Cr, Fe, Al, and Ti metals with a purity greater than 99.5 wt.% into a copper crucible and keeping the furnace in a closed state, and performing melting in an argon atmosphere to exclude the possibility of high-temperature oxidation. After all are melted, gently stir to remove the oxide layer and impurities on the surface of the melt. Usually, the alloy is melted five times repeatedly to ensure the chemical homogeneity of the as-cast alloy.
[0053] S2. Subject the cold-rolled sheet of Ni-based high-entropy alloy to segmented heat treatment to reduce the diffusion rate of atoms in the cold-rolled sheet of Ni-based high-entropy alloy and obtain a Ni-based high-entropy alloy; wherein, the segmented heat treatment includes: heat treatment with a heating section, an aging section with a set temperature and a set pressure, and a cooling section arranged in sequence.
[0054] In some embodiments, the set pressure is 3 GPa to 5 GPa; and / or,
[0055] the set temperature is 900 °C to 1100 °C.
[0056] In some embodiments, the time of the aging section is 1 h to 2 h.
[0057] In the embodiments of the present application, the process of "ageing the Ni-based high-entropy alloy cold hard plate under a set pressure" is a process of high-pressure ageing treatment for the Ni-based high-entropy alloy cold hard plate. High-pressure ageing treatment is a material strengthening method that combines high pressure and ageing treatment. In a high-pressure environment, the atomic diffusion in the metal material is inhibited, and the dislocation movement becomes difficult, thereby making the microstructure inside the material more stable. At the same time, during the ageing treatment process, alloying elements will diffuse and precipitate in the matrix to form fine precipitation phases. High pressure will inhibit the nucleation and growth process of the strengthening phase, making it more evenly distributed in the matrix, thereby improving the mechanical properties of the material.
[0058] When the Ni-based high-entropy alloy cold hard plate is aged under a set pressure of 3 GPa to 5 GPa, the movement speed of the atoms in the Ni-based high-entropy alloy cold hard plate caused by the ageing treatment can be inhibited, thereby inhibiting the rapid growth of grains and reducing the degree of recrystallization. Furthermore, the recrystallization temperature of the Ni-based high-entropy alloy can be effectively increased, the anti-softening failure ability of the Ni-based high-entropy alloy at high temperatures can be improved, and then the high-temperature strength and stability of the Ni-based high-entropy alloy can be improved. Finally, the Ni-based high-entropy alloy has excellent mechanical properties. If the set pressure is higher than 5 GPa, it may cause the sample size of the Ni-based high-entropy alloy to decrease, which is not economical; if the set pressure is lower than 3 GPa, it may be difficult to achieve the purpose of increasing the recrystallization temperature of the Ni-based high-entropy alloy. Exemplarily, the set pressure can be 3 GPa, 3.2 GPa, 3.4 GPa, 3.6 GPa, 3.8 GPa, 4 GPa, 4.2 GPa, 4.4 GPa, 4.6 GPa, 4.8 GPa, 5 GPa, etc.
[0059] The set temperature can be 900 °C to 1100 °C, so as to control the grain size and recrystallization degree of the Ni-based high-entropy alloy hard plate. The time of the ageing stage can be 1 h to 2 h. Low-temperature long-term heat preservation is conducive to the slow growth of grains and the precipitation of nano-precipitation phases. Exemplarily, the temperature of the ageing treatment can be 900 °C, 930 °C, 950 °C, 980 °C, 1000 °C, 1030 °C, 1050 °C, 1080 °C, 1100 °C, etc.; the time can be 1 h, 1.2 h, 1.4 h, 1.6 h, 1.8 h, 2 h, etc.
[0060] In some embodiments, the heating rate of the heating stage is 120 °C / min to 150 °C / min; and / or,
[0061] The cooling rate of the cooling stage is 150 °C / min to 200 °C / min.
[0062] The heating rate of the heating section can be 120℃ / min~150℃ / min, which can achieve the purpose of uniform heating. The cooling rate of the cooling section is 150℃ / min~200℃ / min. The uniform pressure reduction is accompanied by uniform temperature reduction to prevent the hammer from bursting due to excessive speed. Exemplarily, the heating rate of the heating section can be 120℃ / min, 130℃ / min, 140℃ / min, 150℃ / min, etc.; the cooling rate of the cooling section can be 150℃ / min, 160℃ / min, 170℃ / min, 180℃ / min, 190℃ / min, 200℃ / min, etc.
[0063] The method for preparing a Ni-based high entropy alloy provided in the embodiment of the present application has the following advantages:
[0064] 1. Mechanism of action of pressure aging treatment
[0065] Inhibition of atomic diffusion rate: During the aging treatment, the diffusion movement of atoms plays a key role in the evolution of the alloy microstructure. Under normal circumstances, atomic diffusion promotes the formation and growth of new phases. Under set pressure, the atomic diffusion rate decreases. This inhibitory effect can be understood from the perspectives of thermodynamics and kinetics. From a thermodynamic point of view, pressure changes the free energy of the system and increases the energy barrier that needs to be overcome for atomic diffusion; from a kinetic point of view, pressure may affect the vibration frequency and diffusion path of atoms, making it more difficult for atoms to migrate over long distances.
[0066] 2. Inhibit grain growth and reduce the degree of recrystallization
[0067] Grain growth: During the aging process, if there is no pressure restriction, the rapid diffusion of atoms will lead to grain boundary migration, so that the grains will continue to swallow up the surrounding small grains and grow. However, under pressure, the atomic diffusion is limited and the power of grain boundary migration is insufficient, because grain boundary migration requires the rearrangement and diffusion of atoms at the grain boundary, so the rapid growth of grains can be effectively inhibited.
[0068] In terms of the degree of recrystallization: Recrystallization is a process that eliminates work hardening through atomic diffusion and grain boundary migration. When the atomic diffusion rate slows down, the nucleation and growth of new non-distorted grains will be inhibited, thereby reducing the degree of recrystallization. The number of recrystallized grains that may have been formed in large quantities during normal aging is reduced, and the recrystallization process is delayed.
[0069] 3. Influence on recrystallization temperature
[0070] By suppressing grain growth and the degree of recrystallization, the microstructure of the alloy becomes more stable. The recrystallization temperature is closely related to the microstructure of the alloy. When the alloy can maintain a stable microstructure at a higher temperature without obvious recrystallization, it means that its recrystallization temperature has been increased, thereby improving the high-temperature strength and stability of the Ni-based high-entropy alloy. This improvement is of great significance for the application of Ni-based high-entropy alloys in high-temperature environments because it allows the alloy to still maintain good mechanical properties at higher temperatures and reduces the possibility of softening failure. For example, in high-temperature application fields such as aerospace, Ni-based high-entropy alloys with increased recrystallization temperature can better meet the requirements of components for high-temperature strength and stability.
[0071] In a second aspect, the present application provides a Ni-based high-entropy alloy prepared by the method according to any one of the first aspect.
[0072] This Ni-based high-entropy alloy is realized based on the preparation method of the above Ni-based high-entropy alloy. The specific steps of the preparation method of this Ni-based high-entropy alloy can refer to the above embodiments. Since this Ni-based high-entropy alloy adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.
[0073] The following will further illustrate the present application in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. The experimental methods without specific conditions noted in the following embodiments are usually determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions or the conditions recommended by the manufacturer.
[0074] Example 1
[0075] A preparation method of a Ni-based high-entropy alloy, comprising: putting Ni, Co, Cr, Fe, Al and Ti into an arc melting furnace, evacuating and filling with argon after closing, the melting temperature is about 2000 °C, and after all are melted, gently stir to remove the oxide layer and impurities on the surface of the melt, and then quickly cast into a copper mold to form an ingot; wherein, the experimental materials are pure Ni (purity 99.99%), pure Co (purity 99.99%), pure Cr (purity 99.9%), pure Fe (purity 99.9%), pure Al (purity 99.9%) and pure Ti (purity 99.99%); the total atomic fraction of Ni, Co, Cr and Fe is 91%, and the total atomic fraction of Al and Ti is 9%;
[0076] Solution treatment: placing the alloy ingot in an air furnace at 1200 °C for 2 hours, taking it out and quenching it in water to room temperature;
[0077] Cold rolling: First, roll the round ingot to a thickness of 8 mm, then perform solution treatment by holding it in an air furnace at 1200 °C for 2 hours, and after taking it out, quench it in water to room temperature; perform room-temperature rolling on a rolling mill at a speed of 100 mm / s, with the reduction per pass being about 0.1 - 0.5 mm. After multiple passes of rolling, roll the sheet thickness to 1.6 mm, and the total reduction rate is 80%.
[0078] Heat treatment: Perform segmented heat treatment on the cold-rolled plate of the Ni-based high-entropy alloy to reduce the diffusion rate of atoms in the cold-rolled plate of the Ni-based high-entropy alloy and obtain the Ni-based high-entropy alloy; among them, the segmented heat treatment includes: a heat treatment including a heating section, an aging section with a set temperature and a set pressure, and a cooling section set in sequence.
[0079] The heating rate of the heating section is 130 °C / min;
[0080] Aging section: Age and hold at a pressure of 4 GPa and a temperature of 900 °C for 1 h in a six-sided top press;
[0081] The cooling rate of the cooling section is 180 °C / min (water-cooled to room temperature).
[0082] Example 2
[0083] A preparation method of a Ni-based high-entropy alloy, comprising: putting Ni, Co, Cr, Fe, Al, and Ti into an arc melting furnace, closing it, evacuating it, and filling it with argon. The melting temperature is about 2000 °C. After all are melted, gently stir to remove the oxide layer and impurities on the surface of the melt, and then quickly cast it into a copper mold to form an ingot; among them, the experimental materials are pure Ni (purity 99.99%), pure Co (purity 99.99%), pure Cr (purity 99.9%), pure Fe (purity 99.9%), pure Al (purity 99.9%), and pure Ti (purity 99.99%); the total atomic fraction of Ni, Co, Cr, and Fe is 91%, and the total atomic fraction of Al and Ti is 9%;
[0084] Solution treatment: Place the alloy ingot in an air furnace at 1200 °C and hold for 2 hours, and after taking it out, quench it in water to room temperature;
[0085] Cold rolling: First, roll the round ingot to a thickness of about 8 mm, then perform solution treatment by holding it in an air furnace at 1200 °C for 2 hours, and after taking it out, quench it in water to room temperature; perform room-temperature rolling on a rolling mill at a speed of 100 mm / s, with the reduction per pass being 0.1 mm - 0.5 mm. After multiple passes of rolling, roll the sheet thickness to 1.6 mm, and the total reduction rate is 80%.
[0086] Heat treatment: The Ni-based high-entropy alloy cold hard plate is subjected to segmented heat treatment to reduce the diffusion rate of atoms in the Ni-based high-entropy alloy cold hard plate, and a Ni-based high-entropy alloy is obtained; wherein, the segmented heat treatment includes: a heat treatment of a heating section, an aging section with a set temperature and a set pressure, and a cooling section arranged in sequence.
[0087] The heating rate of the heating section is 130 °C / min;
[0088] Aging section: Aging and heat preservation for 1 h at a pressure of 4 GPa and a temperature of 1000 °C in a six-anvil press;
[0089] The cooling rate of the cooling section is 180 °C / min (water-cooled to room temperature).
[0090] Example 3
[0091] A preparation method of a Ni-based high-entropy alloy, comprising: putting Ni, Co, Cr, Fe, Al and Ti into an arc melting furnace, evacuating and filling with argon after closing, the melting temperature is about 2000 °C, and after all are melted, gently stir to remove the oxide layer and impurities on the surface of the melt, and then quickly cast into a copper mold to form an ingot; wherein, the experimental materials are pure Ni (purity 99.99%), pure Co (purity 99.99%), pure Cr (purity 99.9%), pure Fe (purity 99.9%), pure Al (purity 99.9%) and pure Ti (purity 99.99%); the total atomic fraction of Ni, Co, Cr and Fe is 91%, and the total atomic fraction of Al and Ti is 9%;
[0092] Solution treatment: Place the alloy ingot in an air furnace at 1200 °C for heat preservation for 2 hours, take it out and water-quench it to room temperature;
[0093] Cold rolling: First roll the round ingot to a thickness of 8 mm, then perform solution treatment by heat preservation in an air furnace at 1200 °C for 2 hours, take it out and water-quench it to room temperature; Roll at a speed of 100 mm / s on a rolling mill at room temperature, the reduction per pass is 0.1 mm to 0.5 mm, after multi-pass rolling, roll the sheet thickness to 1.6 mm, and the total reduction rate is 80%.
[0094] Heat treatment: The Ni-based high-entropy alloy cold hard plate is subjected to segmented heat treatment to reduce the diffusion rate of atoms in the Ni-based high-entropy alloy cold hard plate, and a Ni-based high-entropy alloy is obtained; wherein, the segmented heat treatment includes: a heat treatment of a heating section, an aging section with a set temperature and a set pressure, and a cooling section arranged in sequence.
[0095] The heating rate of the heating section is 130 °C / min;
[0096] Aging section: Aging and heat preservation for 1 h at a pressure of 4 GPa and a temperature of 1100 °C in a six-anvil press;
[0097] The cooling rate in the cooling section is 180 °C / min (water-cooled to room temperature).
[0098] Example 4
[0099] Based on the disclosure of Example 1, the difference between Example 4 and Example 1 lies in: high-pressure aging treatment: the pressure is 3 GPa.
[0100] Example 5
[0101] Based on the disclosure of Example 1, the difference between Example 5 and Example 1 lies in: high-pressure aging treatment: the pressure is 5 GPa.
[0102] Comparative Example 1
[0103] Based on the disclosure of Example 1, the difference between Comparative Example 1 and Example 1 lies in: atmospheric-pressure aging treatment.
[0104] Comparative Example 2
[0105] Based on the disclosure of Example 2, the difference between Comparative Example 2 and Example 2 lies in: atmospheric-pressure aging treatment.
[0106] Comparative Example 3
[0107] Based on the disclosure of Example 3, the difference between Comparative Example 3 and Example 3 lies in: atmospheric-pressure aging treatment.
[0108] The mechanical properties of the Ni-based high-entropy alloys prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were tested. Please refer to Table 1.
[0109] Table 1 Mechanical properties of Ni-based high-entropy alloys
[0110]
[0111]
[0112] As can be seen from Table 1, increasing the pressure is beneficial to the improvement of the strength and hardness of the alloy but sacrifices the plasticity; increasing the aging temperature is beneficial to the improvement of its plasticity. The Ni-based high-entropy alloys obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were subjected to metallographic scanning to obtain metallographic structures respectively. Figure 2 This is the metallographic diagram of a Ni-based high-entropy alloy provided in Example 1 of this application; Figure 3 This is the metallographic diagram of a Ni-based high-entropy alloy provided in Example 2 of this application; Figure 4 This is the metallographic diagram of a Ni-based high-entropy alloy provided in Example 3 of this application; Figure 5 This is the metallographic diagram of a Ni-based high-entropy alloy provided in Comparative Example 1 of this application; Figure 6The metallographic diagram of a Ni-based high-entropy alloy provided for Comparative Example 2 of this application; Figure 7 The metallographic diagram of a Ni-based high-entropy alloy provided for Comparative Example 3 of this application; Please refer to Figures 2 to 7 , it can be seen from Figures 2 to 4 that under high pressure, with the increase of the heat treatment temperature, the recrystallization degree of the alloy structure also gradually increases; it can be seen from Figures 5 to 7 that under normal pressure, with the increase of the heat treatment temperature, the recrystallization degree of the alloy structure increases; from Figure 1 and 4 , by comparing 2 and 5, 3 and 6 one by one, it can be found that under the same heat treatment conditions, high pressure inhibits the recrystallization degree of the alloy and prevents the growth of grains, thereby promoting the improvement of the alloy performance; Figure 8 The stress-strain comparison curve diagram of a Ni-based high-entropy alloy provided for Example 3 and Comparative Example 3 of this application, please refer to Figure 8 , indicating that the alloy after high-pressure treatment has a higher yield strength.
[0113] One or more technical solutions in the embodiments of this application at least further have the following technical effects or advantages:
[0114] (1) The preparation method of this Ni-based high-entropy alloy realizes the inhibition of grain growth and plays a role in fine-grain strengthening of the alloy performance;
[0115] (2) The coupling effect of the set temperature and the set pressure can actively guide the dynamic recrystallization process of the alloy.
[0116] The above are only the specific implementation manners of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A method for preparing a Ni-based high entropy alloy, the method comprising: Obtaining a Ni-based high entropy alloy chilled plate with a set chemical composition, wherein the set chemical composition includes: Ni, Co, Cr and Fe; The Ni-based high entropy alloy cold-hardened plate is subjected to a segmented heat treatment to reduce the diffusion rate of atoms in the Ni-based high entropy alloy cold-hardened plate to obtain a Ni-based high entropy alloy; wherein the segmented heat treatment includes: a heating section, an aging section with a set temperature and a set pressure, and a cooling section heat treatment which are sequentially arranged.
2. The method according to claim 1, characterized in that The set pressure is 3 GPa to 5 GPa; and / or, The set temperature is 900℃~1100℃.
3. The method according to claim 2, characterized in that The duration of the aging period is 1 hour to 2 hours.
4. The method according to claim 1, characterized in that: In terms of atomic percentage, the total atomic content of Ni, Co, Cr and Fe is 90% to 92%.
5. The method according to claim 1 or 4, characterized in that: The set chemical composition also includes: Al and / or Ti.
6. The method according to claim 1, characterized in that The heating rate of the heating section is 120°C / min to 150°C / min; and / or, The cooling rate of the cooling section is 150°C / min to 200°C / min.
7. The method according to claim 1, characterized in that The method of obtaining a Ni-based high entropy alloy chilled plate having a set chemical composition comprises: Subjecting a Ni-based high entropy alloy ingot having a set chemical composition to a first solid solution treatment; The Ni-based high entropy alloy ingot after the first solid solution treatment is sequentially subjected to a first rolling, a second solid solution treatment and a second rolling to obtain a Ni-based high entropy alloy chilled plate with a set chemical composition.
8. The method according to claim 7, characterized in that The holding temperatures of the first solution treatment and the second solution treatment are 1150° C. to 1200° C. respectively.
9. The method according to claim 7, characterized in that: The second rolling is a multi-pass rolling, and the process parameters of the multi-pass rolling include: a rolling speed of 100 mm / s to 120 mm / s, and a pressing amount of 0.1 mm to 0.5 mm in each pass.
10. A Ni-based high entropy alloy, wherein the Ni-based high entropy alloy is prepared by the method according to any one of claims 1 to 9.