Rare earth modified high-entropy alloy and preparation method and application thereof

Abstract

The invention discloses a rare earth modified high-entropy alloy and a preparation method and application thereof. The rare earth modified high-entropy alloy comprises a metal element and a rare earth element oxide used as a reinforcement phase, the metal elements are Cu, Fe, Ni, Mn and Ti; and the rare earth element oxide used as the reinforcing phase is selected from one or more of La2O3, MoO2, Er2O3, Ta2O3, Y2O3, Yb2O3, Sm2O3, Gd2O3 and CeO. According to the preparation method of the rare earth modified high-performance high-entropy alloy provided by the invention, a new preparation process of hot isostatic pressing is introduced, so that the density of the material is improved, internal defects are reduced, and the strength of the material is improved.

Description

Technical Field

[0001] This invention belongs to the field of high-entropy alloy technology, and in particular relates to a rare-earth modified high-entropy alloy, its preparation method and application. Background Technology

[0002] High-entropy alloys (HEAs) are alloys composed of five or more metallic elements in approximately equal proportions. A significant characteristic of HEAs compared to traditional alloys is the lack of a main component; the mass fraction or mole fraction of each component element is similar. Traditionally, increasing the number of metals in an alloy is thought to lead to embrittlement. However, HEAs defy this perception; even with multiple metallic elements, embrittlement does not occur, making them a new type of material.

[0003] The CuFeNiMnTi alloy composition suffers from low forming efficiency due to the influence of copper deformation volume. Simultaneously, the high-temperature nickel alloy within the composition places higher demands on processing temperature. To improve forming performance, this invention determines the optimal ratio range by altering the alloy composition proportions. To enhance the mechanical properties of the high-entropy alloy composition, various rare earth element addition schemes were explored, and suitable materials were identified. For example, the addition of Ta₂O₃ significantly improved the damping performance of the original alloy composition; the introduction of La₂O₃ significantly enhanced the compressive strength of the alloy. Summary of the Invention

[0004] In view of this, the present invention aims to provide a rare earth-modified high-entropy alloy, its preparation method and application, in order to solve at least one technical problem in the background art.

[0005] A rare earth-modified high-entropy alloy comprising metallic elements and rare earth element oxides used as reinforcing phases; The metallic elements are Cu, Fe, Ni, Mn, and Ti; The rare earth element oxides used as reinforcing phases are selected from one or more of La2O3, MoO2, Er2O3, Ta2O3, Y2O3, Yb2O3, Sm2O3, Gd2O3, and CeO.

[0006] Furthermore, the molar ratio of Cu, Fe, Ni, Mn and Ti is (0.25-1):(0.8-1.2):(0.8-1.2):(0.8-1.2):(0.8-1.2).

[0007] Furthermore, based on the total mass of the metal elements, the amount of rare earth element oxides added is 0.5-2 wt.%.

[0008] The preparation method of the above-mentioned rare earth modified high-entropy alloy includes the following steps: S1: Mix copper powder, iron powder, nickel powder, manganese powder and titanium powder, and then ball mill them under a protective gas to obtain alloyed powder; S2: The alloyed powder obtained in step S1 is mixed with rare earth element oxide powder to obtain a mixed powder; S3: The mixed powder obtained in step S2 is loaded into a carbon steel sleeve, and then degassed and hot isostatically pressed in sequence to obtain the high-entropy alloy with enhanced performance.

[0009] Furthermore, the protective gas in step S1 is selected from argon, nitrogen, and helium.

[0010] Furthermore, the ball milling in step S1 includes a first ball milling and a second ball milling performed sequentially; Preferably, the rotational speed of the first ball mill is 350-500 rpm / min; Preferably, the first ball milling time is 7-10 hours; Preferably, the rotational speed of the second ball mill is 100-200 rpm / min; Preferably, the second ball milling time is 10-20 minutes; Preferably, the average particle size of the alloyed powder obtained after the second ball milling is 23.5-25.2 μm.

[0011] Furthermore, the mixing of alloying powder and rare earth element oxide powder in step S2 includes mixing the alloying powder and rare earth element oxide powder in a three-dimensional mixer for 6-10 hours at a speed of 25-35 r / min.

[0012] Furthermore, the degassing temperature in step S3 is 300-600℃; Preferably, the vacuum degree of the degassing treatment is ≤2×10⁻⁶. -3 Pa; Preferably, the heat preservation time for the degassing treatment is 2.5-5 hours.

[0013] Furthermore, the temperature of the hot isostatic pressing is 900-1100℃, and the holding time is at least 2 hours; The pressure of the hot isostatic pressing is 100-170 MPa; Preferably, the heating method for hot isostatic pressing includes single-stage heating or segmented heating: If the heating method of hot isostatic pressing is a one-stage heating, the final temperature is 900-1100℃ and the holding time is ≥2h; If the heating method of hot isostatic pressing is a two-stage heating, hot isostatic pressing includes a first heating and a second heating in sequence. The temperature of the first heating is 900-1000℃ and the holding time is 1-2h. The temperature of the second heating is 1000-1060℃ and the holding time is 0.5h-1h. Preferably, the hot isostatic pressing is followed by a uniform and rapid cooling process.

[0014] The high-entropy alloy prepared by the above-mentioned method of rare earth modified high-entropy alloy is used for the preparation of materials with high compressive strength and high damping properties.

[0015] Materials with high compressive strength and high damping properties are used in the contact surfaces of two relatively moving devices, such as the connection between an aero-engine impeller and the fuselage.

[0016] The purpose of this invention is to provide a high-entropy alloy composition with excellent mechanical properties and damping properties, and its preparation method. By adding different rare earth element oxides, the mechanical properties of the alloy are improved while the damping properties are enhanced. The high-entropy alloy with enhanced properties can be obtained by combining ball milling and hot isostatic pressing.

[0017] To achieve the above objectives, the technical solution of the present invention is implemented as follows: Compared with existing technologies, the rare-earth-modified high-entropy alloy, its preparation method, and its application described in this invention have the following advantages: 1. The method for preparing rare earth modified high-performance high-entropy alloys provided by the present invention introduces the emerging preparation process of hot isostatic pressing, which improves the density of the material and reduces internal defects, thereby enhancing the strength of the material.

[0018] 2. The rare earth modified high-performance high-entropy alloy reinforcing component provided by the present invention effectively refines the grains and pins dislocations by adding rare earth oxides such as La2O3 and MoO2, thereby significantly improving the strength and high-temperature stability of the alloy.

[0019] 3. Rare earth elements form dispersed nano-precipitates with the matrix, enhancing the interfacial damping effect and enabling the alloy to maintain excellent energy dissipation capacity under high-frequency vibration environments. This alloy is suitable for aerospace, precision machinery, and other fields with stringent vibration reduction requirements, demonstrating broad application prospects. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 The damping performance parameter Q of Comparative Example 2 and Example 6 proposed in this invention is the internal friction value. -1 Comparison of curves showing changes with increasing vibration frequency. Detailed Implementation

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0022] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] Example 1 This embodiment provides a rare earth-modified high-performance high-entropy alloy and its preparation method. The high-entropy alloy includes Cu, Fe, Ni, Mn, Ti and rare earth element oxides La2O3, and the mass ratio of Cu, Fe, Ni, Mn and Ti is 0.5:1:1:1:1. Based on the total mass of the aforementioned metallic elements, the amount of rare earth element oxide La2O3 is 1 wt.%. The preparation method includes the following steps: Copper powder, iron powder, nickel powder, manganese powder and titanium powder are mixed in proportion, and then alloyed powder is obtained by first ball milling and second ball milling under argon atmosphere. The first ball milling speed is 400 rpm / min and the time is 8 h; the second ball milling speed is 150 rpm / min and the time is 15 min. The particle size of the alloyed powder is 24.5 μm.

[0024] Take out the powder obtained in step (1), add 1 wt.% La2O3 powder, and then put it into a three-dimensional mixer to mix for 8 hours at a speed of 30 r / min; (3) The alloyed powder obtained in step (2) is loaded into a carbon steel sleeve, and then degassing and hot isostatic pressing are performed in sequence to obtain the high entropy alloy with enhanced performance. The degassing process is performed at a temperature of 450°C and a vacuum degree of 2×10⁻⁶. -3 Pa, heat preservation time is 2 hours; The hot isostatic pressing is a two-stage heating process with a pressure of 160 MPa. The first heating is at 950°C and held for 1.5 hours, and the second heating is at 1030°C and held for 0.5 hours.

[0025] After hot isostatic pressing, the equipment was successively cooled to room temperature and machined. After cooling to room temperature, the equipment was removed and then its performance was tested.

[0026] This method yields high-entropy alloys with up to 51% improved damping performance, up to 31% improved compressive stress, and up to 27% improved hardness. The addition of multiple reinforcing phases not only improves the damping performance of the original high-entropy alloy group but also simultaneously enhances its mechanical properties. This provides a new solution for improving the comprehensive performance of high-entropy alloys under complex service environments. Furthermore, the hot isostatic pressing process effectively densifies the alloy, resulting in a uniform microstructure with no obvious porosity, which enhances the material's fatigue resistance and significantly extends its service life.

[0027] Example 2 This embodiment provides a rare earth-modified high-performance high-entropy alloy and its preparation method. Except that the reinforcing phase is MoO2, all other conditions are the same as in Example 1.

[0028] Example 3 This embodiment provides a rare earth-modified high-performance high-entropy alloy and its preparation method. Except that the reinforcing phase is Er2O3, all other conditions are the same as in Example 1.

[0029] Example 4 This embodiment provides a rare earth-modified high-performance high-entropy alloy and its preparation method. Except that the reinforcing phase is Y2O3, all other conditions are the same as in Example 1.

[0030] Example 5 This embodiment provides a rare earth-modified high-performance high-entropy alloy and its preparation method. Except that the reinforcing phase is Yb2O3, all other conditions are the same as in Example 1.

[0031] Example 6 This embodiment provides a rare earth-modified high-performance high-entropy alloy and its preparation method. Except that the reinforcing phase is Ta2O3, all other conditions are the same as in Example 1.

[0032] Comparative Example 1 The high-entropy alloy in this comparative example includes Cu, Fe, Ni, Mn, and Ti, with a mass ratio of Cu, Fe, Ni, Mn, and Ti of 0.25:1:1:1:1. Except for the absence of rare earth element oxides, the preparation process is the same as in Example 1.

[0033] Comparative Example 2 The high-entropy alloy in this comparative example includes Cu, Fe, Ni, Mn, and Ti, with a mass ratio of Cu, Fe, Ni, Mn, and Ti of 0.5:1:1:1:1. Except for the absence of rare earth element oxides, the preparation process is the same as in Example 1.

[0034] Comparative Example 3 The high-entropy alloy in this comparative example includes Cu, Fe, Ni, Mn, and Ti, with a mass ratio of Cu, Fe, Ni, Mn, and Ti of 0.75:1:1:1:1. Except for the absence of rare earth element oxides, the preparation process is the same as in Example 1.

[0035] The rare-earth-modified high-entropy alloys prepared in the above embodiments and comparative examples were characterized by measuring damping performance using a dynamic thermomechanical analyzer in single cantilever mode, compressive stress and strain using an electronic universal testing machine, and hardness using a Vickers hardness tester. The results are shown in Table 1.

[0036] Table 1 Summary of test data for examples and comparative studies serial number <![CDATA[Q -1 ]]> Peak stress Microhardness <![CDATA[Example 1 - La2O3]]> 0.02025 1732.6 679 <![CDATA[Example 2 - MoO2]]> 0.02045 1759.8 702 <![CDATA[Example 3 - Er2O3]]> 0.021666 1652.3 639 <![CDATA[Example 4 - Y2O3]]> 0.02168 1636.6 675 <![CDATA[Example 5 - Yb2O3]]> 0.01855 1684.4 664 <![CDATA[Example 6 - Ta2O3]]> 0.0241848 1031.4 518 Comparative Example 1 - - - Comparative Example 2 0.01604 1345.7 552 Comparative Example 3 - - - Q -1 This parameter measures damping performance and describes the system's ability to dissipate energy during vibration. Its value is equal to the ratio of stored energy to dissipated energy.

[0037] Comparative Examples 1 and 3 failed to form properly, making subsequent performance testing impossible, indicating that both excessively low and high Cu content are detrimental to alloy formation. After finding a suitable metal ratio, the examples with added rare earth element oxides exhibited superior overall performance in terms of hardness and damping properties. Example 6 showed the highest internal friction value, increasing by 51% compared to the base material, demonstrating the powerful effect of Ta2O3 in improving the material's damping performance. Examples 1 and 2 showed outstanding performance in hardness, indicating that La2O3 and MoO2 contribute to enhancing the alloy's resistance to deformation. In summary, the appropriate introduction of rare earth element oxides not only improves material formability but also significantly optimizes mechanical properties.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rare-earth modified high-entropy alloy, characterized in that: Includes metallic elements and rare earth element oxides used as reinforcing phases; The metallic elements are Cu, Fe, Ni, Mn, and Ti; The rare earth element oxides used as reinforcing phases are selected from one or more of La2O3, MoO2, Er2O3, Ta2O3, Y2O3, Yb2O3, Sm2O3, Gd2O3, and CeO.

2. The rare-earth modified high-entropy alloy according to claim 1, characterized in that: The molar ratio of Cu, Fe, Ni, Mn and Ti is (0.25-1):(0.8-1.2):(0.8-1.2):(0.8-1.2):(0.8-1.2).

3. The rare-earth modified high-entropy alloy according to claim 1, characterized in that: Based on the total mass of the metal elements, the amount of rare earth element oxides added is 0.5-2 wt.%.

4. A method for preparing a rare-earth modified high-entropy alloy according to any one of claims 1-3, characterized in that: Includes the following steps: S1: Mix copper powder, iron powder, nickel powder, manganese powder and titanium powder, and then ball mill them under a protective gas to obtain alloyed powder; S2: The alloyed powder obtained in step S1 is mixed with rare earth element oxide powder to obtain a mixed powder; S3: The mixed powder obtained in step S2 is loaded into a carbon steel sleeve, and then degassed and hot isostatically pressed in sequence to obtain the high-entropy alloy with enhanced performance.

5. The method for preparing a rare-earth modified high-entropy alloy according to claim 4, characterized in that: The protective gas in step S1 is selected from argon, nitrogen, and helium.

6. The method for preparing a rare-earth modified high-entropy alloy according to claim 4, characterized in that: The ball milling in step S1 includes a first ball milling and a second ball milling performed sequentially. Preferably, the rotational speed of the first ball mill is 350-500 rpm / min; Preferably, the first ball milling time is 7-10 hours; Preferably, the rotational speed of the second ball mill is 100-200 rpm / min; Preferably, the second ball milling time is 10-20 minutes; Preferably, the average particle size of the alloyed powder obtained after the second ball milling is 23.5-25.2 μm.

7. The method for preparing a rare-earth modified high-entropy alloy according to claim 4, characterized in that: In step S2, the mixing of alloying powder and rare earth element oxide powder includes placing the alloying powder and rare earth element oxide powder into a three-dimensional mixer and mixing for 6-10 hours at a speed of 25-35 r / min.

8. The method for preparing a rare-earth modified high-entropy alloy according to claim 4, characterized in that: The degassing temperature in step S3 is 300-600℃; Preferably, the vacuum degree of the degassing treatment is ≤2×10⁻⁶. -3 Pa; Preferably, the heat preservation time for the degassing treatment is 2.5-5 hours.

9. The method for preparing a rare-earth modified high-entropy alloy according to claim 4, characterized in that: The hot isostatic pressing temperature is 900-1100℃, and the holding time is at least 2 hours; The pressure of the hot isostatic pressing is 100-170 MPa; Preferably, the heating method for hot isostatic pressing includes single-stage heating or segmented heating: If the heating method of hot isostatic pressing is a one-stage heating, the final temperature is 900-1100℃ and the holding time is ≥2h; If the heating method of hot isostatic pressing is a two-stage heating, hot isostatic pressing includes a first heating and a second heating in sequence. The temperature of the first heating is 900-1000℃ and the holding time is 1-2h. The temperature of the second heating is 1000-1060℃ and the holding time is 0.5h-1h. Preferably, the hot isostatic pressing is followed by a uniform and rapid cooling process.

10. The high-entropy alloy prepared by the method of preparing a rare-earth modified high-entropy alloy according to any one of claims 1-3 or any one of claims 5-9 is used for the preparation of materials with high compressive strength and high damping properties.

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