A high-temperature-resistant high-entropy alloy and a preparation method thereof

Abstract

This invention provides a high-temperature resistant high-entropy alloy and its preparation method, belonging to the field of high-entropy alloy technology. Based on the total atomic percentage of 100%, the high-entropy alloy comprises the following components: Co 22-28%; Cr 15-21%; Fe 22-28%; Ni 22-28%; Ta 4-8%; Al 0.5-5%; Ti 0-2%; Mo 0-2%. By designing a suitable high-entropy alloy composition, the high-entropy alloy of this invention exhibits excellent mechanical properties and a stable microstructure under high-temperature conditions, thereby improving its application performance in high-temperature environments.

Description

Technical Field

[0001] This invention belongs to the field of high-entropy alloy technology, specifically relating to a high-temperature resistant high-entropy alloy and its preparation method. Background Technology

[0002] High-entropy alloys are a class of alloys composed of five or more elements mixed in approximately equal proportions at the atomic scale. High-entropy alloys possess excellent high-temperature resistance, high strength, corrosion resistance, and wear resistance, thus showing broad application prospects in aerospace, power generation equipment, nuclear power equipment, and automotive fields. However, high-entropy alloys in related technologies still suffer from insufficient high-temperature resistance and poor deformation performance.

[0003] Currently, common methods for preparing high-entropy alloys include vacuum melting, powder metallurgy, mechanical synthesis, and electrochemical deposition. However, these methods have the following limitations: First, these methods often require high temperatures and pressures, resulting in high production costs and the potential for defects such as oxides, nitrides, and bubbles, which reduce alloy performance. Second, due to the large variety of elements, atomic sizes, and chemical properties in high-entropy alloys, existing technologies struggle to precisely control the microstructure and phase structure, hindering the full realization of alloy performance. Third, in existing methods, some elements are prone to volatilization at high temperatures, leading to uneven alloy composition and reduced alloy performance. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a high-temperature resistant, high-entropy alloy and its preparation method.

[0005] The high-temperature resistant high-entropy alloy of this invention, based on a total atomic percentage of 100%, comprises the following components:

[0006]

[0007] The advantages and technical effects of the high-temperature, high-entropy alloy of this invention are as follows:

[0008] By designing a suitable high-entropy alloy composition, the high-entropy alloy of the present invention exhibits excellent mechanical properties and a stable microstructure under high-temperature conditions. At 800°C, its tensile strength reaches over 524 MPa, thereby improving its application performance in high-temperature environments.

[0009] In some embodiments, the high-entropy alloy comprises the following components, based on a total atomic percentage of 100%:

[0010]

[0011] In some embodiments, the high-entropy alloy, based on a total atomic percentage of 100%, comprises the following components:

[0012]

[0013] This invention also provides a method for preparing a high-temperature, high-entropy alloy, comprising the following steps:

[0014] (1) Mix various metal raw materials according to the atomic percentage of the high-entropy alloy to obtain mixed metal raw materials;

[0015] (2) The mixed metal raw materials are melted into alloy ingots by vacuum magnetic levitation melting method;

[0016] (3) The alloy ingot is made into alloy powder by vacuum atomization treatment;

[0017] (4) The alloy powder is compacted and then vacuumed to obtain an alloy powder compact.

[0018] (5) The alloy powder compact is subjected to hot isostatic pressing and furnace cooling to room temperature to obtain the high entropy alloy.

[0019] The advantages and technical effects of the preparation method of the high-temperature resistant high-entropy alloy in this invention are as follows:

[0020] (1) The preparation method of this invention adopts hot isostatic pressing process. Compared with the preparation method of high entropy alloy disclosed in related technologies, the preparation of high entropy alloy can be achieved at a lower temperature and pressure, thus reducing the preparation cost and reducing alloy defects.

[0021] (2) The preparation method of this invention adopts hot isostatic pressing process. Compared with the preparation method of high entropy alloy disclosed in related technologies, the preparation of high entropy alloy can be achieved at a lower temperature. Therefore, the loss of elements during the preparation process can be reduced and the uniformity of alloy composition can be improved.

[0022] (3) The preparation method of the present invention adopts hot isostatic pressing process, which can achieve precise control of the microstructure and phase structure of the alloy to a certain extent and improve the performance of the alloy.

[0023] In some embodiments, in step (3), the particle size of the alloy powder is 45-55 μm.

[0024] In some embodiments, in step (4), the alloy powder is compacted under a pressure of 300-500 MPa.

[0025] In some embodiments, in step (5), the hot isostatic pressing process is performed at a temperature of at least 1200°C, an isostatic pressure of at least 150 MPa, and a holding time of at least 2 hours.

[0026] In some embodiments, in step (5), the temperature in the hot isostatic pressing process is 1150-1250℃, the isostatic pressure is 100-150MPa, and the heat and pressure holding time is 2-4h.

[0027] In some embodiments, the high-entropy alloy is post-treated after step (5), the post-treatment including heat treatment and / or machining.

[0028] In some embodiments, the heat treatment includes solution treatment and / or aging treatment; the machining treatment includes cutting treatment and / or polishing treatment. Attached Figure Description

[0029] Figure 1 This is a schematic flowchart of the preparation method of the high-temperature resistant high-entropy alloy according to an embodiment of the present invention;

[0030] Figure 2 This is a physical image of the high-temperature, high-entropy alloy of Embodiment 1 of the present invention;

[0031] Figure 3 This is the XRD pattern of the high-temperature, high-entropy alloy of Embodiment 1 of the present invention;

[0032] Figure 4 This is the tensile stress-strain curve at 800℃ of the high-temperature resistant, high-entropy alloy of Embodiment 1 of the present invention. Detailed Implementation

[0033] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0034] This invention provides a high-temperature resistant, high-entropy alloy, which, based on a total atomic percentage of 100%, comprises the following components:

[0035]

[0036] By designing suitable high-entropy alloy compositions, the high-entropy alloys of the present invention exhibit excellent mechanical properties and stable microstructures under high-temperature conditions, thereby improving their application performance in high-temperature environments.

[0037] In the high-temperature, high-entropy alloy of this invention, when the atomic percentage of Co is 22-28%, Co plays a role in improving the alloy's strength and stability. When the atomic percentage of Co is below 22%, it is difficult to provide sufficient strength and stability; when the atomic percentage of Co is above 28%, it is difficult to maintain the alloy's good processability. Preferably, the atomic percentage of Co is 24-26%. More preferably, the atomic percentage of Co is 25%.

[0038] In the high-temperature, high-entropy alloy of this invention, when the atomic percentage of Cr is 15-21%, Cr plays a role in improving chemical stability and oxidation resistance. When the atomic percentage of Cr is below 15%, the alloy is difficult to resist high-temperature oxidation; when the atomic percentage of Cr is above 21%, it is difficult to maintain the alloy's plasticity and toughness. Preferably, the atomic percentage of Cr is 17-19%. More preferably, the atomic percentage of Cr is 18%.

[0039] In the high-temperature, high-entropy alloy of this invention, when the atomic percentage of Fe is 22-28%, Fe plays a role in improving the alloy's strength. When the atomic percentage of Fe is below 22%, it is difficult to achieve good alloy strength; when the atomic percentage of Fe is above 28%, it is difficult to maintain the alloy's oxidation resistance. Preferably, the atomic percentage of Fe is 24-26%. More preferably, the atomic percentage of Fe is 25%.

[0040] In the high-temperature, high-entropy alloy of this invention, when the atomic percentage of Ni is 22-28%, Ni plays a role in improving the alloy's oxidation resistance and ductility. When the atomic percentage of Ni is below 22%, the alloy struggles to achieve good oxidation resistance and ductility; when the atomic percentage of Ni is above 28%, it is difficult to maintain the alloy's strength. Preferably, the atomic percentage of Ni is 24-26%. More preferably, the atomic percentage of Ni is 25%.

[0041] In the high-temperature, high-entropy alloy of this invention, when the atomic percentage of Ta is 4-8%, Ni plays a role in improving the alloy's high-temperature creep resistance. When the atomic percentage of Ta is less than 4%, the alloy is difficult to achieve excellent high-temperature creep resistance; when the atomic percentage of Ta is greater than 8%, it is difficult to maintain the alloy's suitable density and processability. Preferably, the atomic percentage of Ta is 5-7%. More preferably, the atomic percentage of Ta is 6%.

[0042] In the high-temperature, high-entropy alloy of this invention, when the atomic percentage of Al is 0.5-5%, Al plays a role in improving the alloy's oxidation resistance and reducing its weight. When the atomic percentage of Al is below 0.5%, it is difficult to provide sufficient oxidation resistance and weight reduction; when the atomic percentage of Al is above 1.5%, it is difficult to maintain the alloy's mechanical properties. Preferably, the atomic percentage of Al is 0.8-1.2%. More preferably, the atomic percentage of Al is 1%.

[0043] In the high-temperature, high-entropy alloy of this invention, when the atomic percentage of Ti is 0-2%, Ti plays a role in improving the alloy's strength. When the atomic percentage of Ti is higher than 2%, it is difficult to maintain the alloy's ductility and processing properties. Preferably, the atomic percentage of Ti is 0-2%.

[0044] In the high-temperature, high-entropy alloy of this invention, when the atomic percentage of Mo is 0-2%, Mo plays a role in resisting creep. When the atomic percentage of Mo is higher than 2%, it is difficult to maintain the balance between the alloy's processing performance and mechanical properties. Preferably, the atomic percentage of Mo is 0-2%.

[0045] This invention also provides a method for preparing a high-temperature, high-entropy alloy, such as... Figure 1 As shown, it includes the following steps:

[0046] (1) Mix various metal raw materials according to the atomic percentage of the high-entropy alloy to obtain mixed metal raw materials;

[0047] (2) The mixed metal raw materials are melted into alloy ingots by vacuum magnetic levitation melting method;

[0048] (3) The alloy ingot is made into alloy powder by vacuum atomization treatment;

[0049] (4) The alloy powder is compacted and then vacuumed to obtain an alloy powder compact.

[0050] (5) The alloy powder compact is subjected to hot isostatic pressing and furnace cooling to room temperature to obtain the high entropy alloy.

[0051] The preparation method of this invention adopts hot isostatic pressing, which, compared with the preparation methods of high-entropy alloys disclosed in related technologies, can achieve the preparation of high-entropy alloys at lower temperatures and pressures, thereby reducing preparation costs and alloy defects. At the same time, it can reduce element loss during the preparation process and improve the uniformity of alloy composition. In addition, it can also achieve precise control of the alloy microstructure and phase structure to a certain extent, thereby improving the alloy performance.

[0052] The preparation method of this invention involves atomizing the alloy ingot into alloy powder using vacuum in step (3), then forming an alloy powder compact in step (4), and finally subjecting the alloy powder compact to hot isostatic pressing in step (5). This ensures that the resulting high-entropy alloy has relatively fine grains and effectively improves its strength, making it suitable for high-temperature service environments. If steps (3) and (4) are omitted and the alloy ingot is directly subjected to hot isostatic pressing, the resulting high-entropy alloy will have relatively coarse grains and relatively low strength, failing to meet the requirements of high-temperature service environments.

[0053] In some embodiments, in step (3), the particle size of the alloy powder is 45-55 μm. When the particle size of the alloy powder is too small, it is not conducive to improving the packing density and mechanical property stability of the alloy, nor is it conducive to subsequent compaction molding; when the particle size of the alloy powder is too large, it is not conducive to improving the density uniformity of subsequent compaction molding, nor is it conducive to reducing the porosity and surface roughness of the alloy powder compact.

[0054] In some embodiments, in step (4), the alloy powder is compacted under a pressure of 300-500 MPa. When the pressure is too low, it is not conducive to improving the forming density of the alloy powder compact and reducing the porosity and mechanical properties of the alloy powder compact; when the pressure is too high, the alloy powder is easily broken and it is not conducive to reducing die wear and cost.

[0055] The temperature and pressure conditions for hot isostatic pressing (HIP) can be adjusted according to the melting points and mechanical properties of the selected alloying elements. By regulating the temperature, pressure, and holding time during HIP, a fine-grained microstructure can be achieved, thereby enabling precise control of the alloy's microstructure and phase structure to a certain extent and improving its performance. However, the preparation methods disclosed in related technologies are casting processes, where the grain structure is uncontrollable, making it difficult to achieve the aforementioned effects.

[0056] Preferably, in some embodiments, in step (5), the hot isostatic pressing treatment is performed at a temperature of at least 1200°C, an isostatic pressure of at least 150 MPa, and a holding time of at least 2 hours. When the temperature is too low, the isostatic pressure is too low, or the holding time is too short, it is not conducive to refining the alloy grains and improving the uniformity of the microstructure and mechanical properties. Preferably, in step (5), the hot isostatic pressing treatment is performed at a temperature of 1150-1250°C, an isostatic pressure of 100-150 MPa, and a holding time of 2-4 hours.

[0057] In some embodiments, the high-entropy alloy is post-treated after step (5), the post-treatment including heat treatment and / or machining to obtain the desired mechanical properties and dimensions. For example, the heat treatment includes solution treatment and / or aging treatment to optimize the microstructure and properties of the alloy. The machining treatment includes cutting and / or polishing to obtain the desired alloy sample shape and surface quality.

[0058] This invention also provides a method for designing the composition of a high-temperature, high-entropy alloy, comprising the following steps:

[0059] S1. Select appropriate basic elements: By selecting appropriate basic elements, including but not limited to Co, Cr, Fe, Ni, Ta, Al, Ti, Mo, etc., the composition design requirements of high-entropy alloys can be met.

[0060] S2. Composition design based on the principle of mixed entropy: Based on the principle of mixed entropy, determine the content and proportion of different elements so that the high-entropy alloy has suitable high-temperature strength and stable microstructure.

[0061] S3. Optimize composition design using thermodynamic calculations and phase diagram analysis: Further optimize composition design through thermodynamic calculations and phase diagram analysis to achieve a stable microstructure and excellent mechanical properties of high-entropy alloys.

[0062] S4. Preparation of high-entropy alloy samples: Based on the composition design scheme, select the preparation method of high-entropy alloy according to the embodiment of the present invention to prepare high-entropy alloy samples.

[0063] S5. Mechanical testing of high-entropy alloy samples: Mechanical testing of the prepared high-entropy alloy samples, including but not limited to thermal stability testing, high-temperature mechanical property testing, plastic deformation and strengthening mechanism research, etc., to verify their high-temperature performance and stable microstructure.

[0064] Through the above steps, the embodiments of the present invention can realize the composition design of high-entropy alloys, thereby exhibiting excellent mechanical properties and stable microstructure under high-temperature conditions, and have broad application prospects.

[0065] The present invention will now be described in detail with reference to the embodiments and accompanying drawings.

[0066] Example 1

[0067] A high-temperature resistant, high-entropy alloy, based on a total atomic percentage of 100%, comprises the following components:

[0068]

[0069] The preparation method of the high-temperature, high-entropy alloy described above includes the following steps:

[0070] (1) Ingredients

[0071] Various metal raw materials are mixed according to the atomic percentage of the high-entropy alloy described above to obtain mixed metal raw materials.

[0072] (2) Metal smelting

[0073] The mixed metal raw materials obtained in step (1) are smelted into alloy ingots by vacuum magnetic levitation melting.

[0074] (3) Air atomization powder production

[0075] The alloy ingot smelted in step (2) is made into alloy powder by gas atomization technology. The particle size of the alloy powder is about 50 μm.

[0076] (4) Compaction molding

[0077] The alloy powder obtained in step (3) is placed into a stainless steel sleeve, and pressure is applied at room temperature to form the alloy powder. The pressure range is 300-500 MPa, and the size of the compacted sample is φ20mm×10mm.

[0078] (5) Vacuuming process

[0079] The inside of the stainless steel sleeve in step (4) is vacuumed to remove internal gas and moisture, thereby improving the density and performance of the final product and obtaining an alloy powder compact.

[0080] (6) Hot isostatic pressing and cooling

[0081] The alloy powder compact obtained in step (5) was placed in a hot isostatic pressing furnace and heated to 1200°C, and held at that temperature for 2 hours. During this process, an isostatic pressure of 150 MPa was applied to the alloy powder compact to densify it. After the hot isostatic pressing treatment was completed, the furnace temperature was slowly reduced to room temperature and allowed to cool naturally to obtain the high-temperature resistant high-entropy alloy.

[0082] (7) Machining

[0083] The cooled high-temperature high-entropy alloy is then subjected to post-processing such as cutting and polishing to obtain the desired shape and surface quality of the high-temperature high-entropy alloy sample.

[0084] (8) Heat treatment

[0085] The high-temperature resistant high-entropy alloy sample obtained in step (7) was heat-treated at 1000℃ for 5 hours and then air-cooled.

[0086] Example 2

[0087] The high-temperature resistant high-entropy alloy of this embodiment, based on a total atomic percentage of 100%, consists of the following components:

[0088]

[0089] The preparation method of the high-temperature resistant high-entropy alloy in this embodiment is the same as that in Example 1.

[0090] Example 3

[0091] The high-temperature resistant high-entropy alloy of this embodiment, based on a total atomic percentage of 100%, consists of the following components:

[0092]

[0093]

[0094] The preparation method of the high-temperature resistant high-entropy alloy in this embodiment is the same as that in Example 1.

[0095] Example 4

[0096] The high-temperature resistant high-entropy alloy of this embodiment, based on a total atomic percentage of 100%, consists of the following components:

[0097]

[0098] The preparation method of the high-temperature resistant high-entropy alloy in this embodiment is the same as that in Example 1.

[0099] Example 5

[0100] The high-temperature resistant high-entropy alloy of this embodiment, based on a total atomic percentage of 100%, consists of the following components:

[0101]

[0102] The preparation method of the high-temperature resistant high-entropy alloy in this embodiment is the same as that in Example 1.

[0103] Comparative Example 1

[0104] The high-temperature resistant high-entropy alloy in this comparative example, based on a total atomic percentage of 100%, consists of the following components:

[0105]

[0106]

[0107] The preparation method of the high-temperature, high-entropy alloy in this comparative example is the same as that in Example 1.

[0108] Comparative Example 2

[0109] The high-entropy alloy and its preparation method in the comparative example are the same as those in Example 1, except that steps (3)-(5) are omitted and the alloy ingot obtained in step (2) is directly subjected to hot isostatic pressing.

[0110] Mechanical property testing:

[0111] Mechanical properties of the high-entropy alloy samples from Examples 1-5 and Comparative Examples 1-2 were tested, including but not limited to thermal stability testing, high-temperature mechanical property testing, plastic deformation and strengthening mechanism studies, in order to verify their high-temperature performance and stable microstructure.

[0112] from Figure 4 It can be seen that the high-temperature resistant high-entropy alloy of Example 1 has a tensile strength of over 524 MPa at 800℃, which meets the requirements of high-temperature service environment.

[0113] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0114] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A high-temperature, high-entropy resistant alloy, characterized in that, Based on a total atomic percentage of 100%, the high-entropy alloy comprises the following components: Co22-28%; Cr15-21%； Fe22-28%; Ni22-28%; Ta4-8%; Al0.5-1.5%； Ti0-2%; Mo0-2%.

2. The high-temperature, high-entropy alloy according to claim 1, characterized in that, Based on a total atomic percentage of 100%, the high-entropy alloy comprises the following components: Co24-26%; Cr17-19%； Fe24-26%; Ni24-26%; Ta5-7%; Al0.5-1.5%； Ti0-2%; Mo0-2%.

3. The high-temperature, high-entropy alloy according to claim 1 or 2, characterized in that, The high-entropy alloy, with a total atomic percentage of 100%, is composed of the following components: Co25%; Cr18%； Fe25%; Ni 25%; Ta6%; Al1%。 4. The method for preparing the high-temperature resistant, high-entropy alloy according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Mix various metal raw materials according to the atomic percentage of the high-entropy alloy to obtain mixed metal raw materials; (2) The mixed metal raw materials are smelted into alloy ingots by vacuum magnetic levitation melting method; (3) The alloy ingot is processed into alloy powder by vacuum atomization; (4) The alloy powder is compacted and then vacuumed to obtain an alloy powder compact; (5) The alloy powder compact is subjected to hot isostatic pressing and furnace cooled to room temperature to obtain the high entropy alloy.

5. The method for preparing the high-temperature, high-entropy alloy according to claim 4, characterized in that, In step (3), the particle size of the alloy powder is 45-55µm.

6. The method for preparing the high-temperature, high-entropy alloy according to claim 4, characterized in that, In step (4), the alloy powder is compacted and formed under a pressure of 300-500 MPa.

7. The method for preparing the high-temperature, high-entropy alloy according to claim 4, characterized in that, In step (5), the temperature in the hot isostatic pressing process is at least 1200°C, the isostatic pressure is at least 150 MPa, and the holding time is at least 2 hours.

8. The method for preparing the high-temperature, high-entropy alloy according to claim 4, characterized in that, After step (5), the high-entropy alloy is subjected to post-treatment, which includes heat treatment and / or machining.

9. The method for preparing the high-temperature, high-entropy alloy according to claim 8, characterized in that, The heat treatment includes solution treatment and / or aging treatment; the machining treatment includes cutting treatment and / or polishing treatment.

Images