A three-dimensional gradient structure multi-principal element alloy material and a preparation method thereof

Abstract

The application belongs to the technical field of multi-principal element alloy material preparation, and particularly relates to a three-dimensional gradient structure multi-principal element alloy material and a preparation method thereof. The preparation method precisely controls the microstructure, grain boundary characteristics and spatial distribution of the strengthening phase of the alloy through airflow grinding, and realizes the preparation of high-performance multi-principal element alloy material performance in combination with a rapid sintering process. The prepared multi-principal element alloy material has high strength and high toughness, can not only meet the high requirements of modern engineering fields on material performance, but also can provide a new technical scheme for the industrial production of other high-performance materials.

Description

A three-dimensional gradient structure multi-principal element alloy material and its preparation method Technical Field

[0001] This invention belongs to the field of multi-principal element alloy material preparation technology, and particularly relates to a three-dimensional gradient structure multi-principal element alloy material and its preparation method. Background Technology

[0002] In recent years, with the rapid development of industrialization and technology, the demand for materials possessing both high strength and high toughness has been increasing in the modern engineering field. Behind this demand is the urgent need for lighter, higher-performance, and safer materials to meet the evolving challenges in aerospace, automotive manufacturing, energy equipment, and electronics. Multi-principal element alloys, through the rational design of different component contents, have demonstrated enormous potential to simultaneously provide high strength and high toughness, and are therefore highly favored in the engineering field.

[0003] Gradient structure design, based on the synergistic deformation between regions with significantly different structural compositions, is widely used to improve the strength-plasticity matching ability of materials. However, traditional fabrication techniques such as casting, rolling, and extrusion are often limited by material composition and processes, making it difficult to achieve precise control of the microstructure of multi-principal element alloys, especially for the preparation of multi-scale microstructure materials. Furthermore, traditional fabrication processes suffer from high energy consumption and long production cycles, resulting in high costs and low efficiency. Powder metallurgy is a common method for preparing multi-scale heterogeneous materials, but ball milling requires the addition of grinding aids that are difficult to remove completely, inevitably introducing milling impurities, reducing material purity, and ultimately limiting further improvements in material properties. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention aims to propose a three-dimensional gradient structure multi-principal element alloy material and its preparation method. By precisely controlling the microstructure, grain boundary characteristics, and spatial distribution of reinforcing phases through air jet milling, combined with a rapid sintering process, high-performance multi-principal element alloy materials are prepared. The prepared multi-principal element alloy material possesses both high strength and high toughness, which not only meets the high performance requirements of modern engineering fields but also provides a new technical solution for the industrial production of other high-performance materials.

[0005] The specific technical solution of the present invention is as follows:

[0006] A three-dimensional gradient structure multi-principal element alloy material is composed of nanoscale TiB2 reinforcing phase, nanoscale TiC reinforcing phase and VCoNiAlTi alloy. The surface grains of the VCoNiAlTi alloy are submicron-sized and the core grains are micron-sized. The nanoscale TiB2 reinforcing phase and nanoscale TiC reinforcing phase periodically encapsulate the VCoNiAlTi alloy.

[0007] A preparation method of a three-dimensional gradient structure multi-principal element alloy material, comprising the following steps:

[0008] Step S1: Mix the multi-principal element alloy powder and the strengthening phase powder to obtain a mixed powder;

[0009] The composition of the multi-principal element alloy powder is (VCoNi) , , , , , , ,

[0017] ,

[0016] , -3 ,

[0015] ,

[0014] ,

[0013] ,

[0019] ,

[0018] (AlTi) X , where X is the atomic percentage, 0 < X ≤ 10; the atomic content of each of the elements V, Co, and Ni is 20-40%, and the strengthening phase powder includes TiB2 powder and TiC powder;

[0010] Step S2: Perform jet milling on the mixed powder to obtain spherical powder in which the strengthening phase powder uniformly coats the multi-principal element alloy powder;

[0011] Step S3: Perform degassing treatment on the spherical powder in a cladding;

[0012] Step S4: Place the cladding in a hot isostatic press furnace for hot isostatic pressing and sintering to form.

[0013] Preferably, in the mixed powder of step S1, the mass fraction of TiB2 powder is 0.5-2.5%, the mass fraction of TiC powder is 0.5-2.5%, and the rest is multi-principal element alloy powder.

[0014] Preferably, the multi-principal element alloy powder is prepared by gas atomization or rotary electrode method, with an average particle size of 50-150 μm, the average size of TiB2 powder is less than 1 μm, and the average size of TiC powder is less than 1 μm.

[0015] Preferably, the mixing treatment in step S1 is carried out in an atmosphere protection environment, the mixing speed is 30-60 revolutions per minute, and the mixing time is 1-2 hours.

[0016] Preferably, in the jet milling treatment of step S2, argon with an oxygen content lower than 5 ppm is used as the impact gas source, the gas pressure is 1.0-1.5 MPa, the feeding speed is 0.12-0.25 g / s, and the number of jet milling cycles is 5-20 times.

[0017] Preferably, the jet milling treatment in step S2 is carried out in a glove box with atmosphere protection.

[0018] Preferably, step S3 specifically includes: loading the obtained spherical powder into a cladding for degassing treatment, the degassing temperature is 400-500 °C, and when the vacuum degree in the cladding is better than 5×10 <​​​Preferably, in the hot isostatic pressing sintering of step S4, the temperature is raised to 900-1100°C at a heating rate of 10-50°C / min, the sintering pressure is 200 MPa, and the sintering time is 2-4 hours.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] (1) In the preparation process of the three-dimensional gradient structure multi-principal element alloy material proposed in this invention, there is no powder oxidation and no impurities are introduced. Unlike the traditional ball milling process, there is no need to remove grinding aids in the later stage.

[0022] (2) The preparation method of a three-dimensional gradient structure multi-principal element alloy material proposed in this invention has a simple process flow, does not require subsequent heat treatment, and is suitable for mass production.

[0023] (3) The three-dimensional gradient structure multi-principal element alloy material prepared by the present invention consists of a VCoNiAlTi alloy with nano-scale TiB2 and TiC reinforcing phases periodically wrapping the surface submicron-scale and core micron-scale grains. Its microstructure can be precisely controlled, and its mechanical properties such as yield strength, tensile strength and uniform elongation are excellent. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly introduced below. The features and advantages of the present invention can be more clearly understood by referring to the accompanying drawings. The accompanying drawings are schematic and should not be construed as limiting the present invention in any way. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 is a schematic diagram of the microstructure of the three-dimensional gradient structure multi-principal element alloy material of the present invention. Detailed Implementation

[0026] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0028] Example 1

[0029] A method for preparing a three-dimensional gradient structure multi-principal element alloy material includes the following steps:

[0030] Step 1: Mixing and processing of multi-principal element alloy powder with reinforcing phase powder

[0031] Multi-principal component alloy powder, TiB2, and TiC powder were thoroughly mixed in a V-type mixer. The multi-principal component alloy powder was a spherical powder prepared by gas atomization or rotating electrode method, with an average particle size of 100 μm, and its specific composition was (VCoNi). 100-X (AlTi) X Where X represents the atomic percentage, X = 10; the atomic content of each of V, Co, and Ni is 30%, and Al and Ti are in equiatomic ratio. The average size of TiB2 powder is 500 nm, accounting for 0.5% by mass; the average size of TiC powder is 800 nm, accounting for 0.5% by mass; the mixing speed is 60 rpm, and the mixing time is 1 hour. To prevent powder oxidation during the mixing process, mixing is carried out in a protective atmosphere.

[0032] Step 2: Mixed powder airflow milling

[0033] The mixed powder was added to a dedicated air jet mill jar for impact deformation treatment. Argon gas with an oxygen content of less than 5 ppm was used as the impact gas source, the gas pressure was adjusted to 1.0 MPa, the feeding rate was 0.25 g / s, and the air jet mill cycle was 20 times. Finally, spherical powders uniformly coated with multi-principal element alloys by TiB2 and TiC powders were obtained. All the above operations were carried out in a glove box with a protected atmosphere to prevent oxidation.

[0034] Step 3: Degassing treatment with a protective casing

[0035] The mixed powder was placed in a stainless steel enclosure and subjected to high-temperature degassing at 400°C. The vacuum level inside the enclosure was then determined to be better than 5 × 10⁻⁶. -3 After Pa, the sleeve is sealed by welding.

[0036] Step 4: Hot isostatic pressing and sintering

[0037] The cladding is placed in a hot isostatic pressing furnace for sintering. It is heated to 900°C at a heating rate of 50°C / min, while pressure is applied uniformly in all directions to a sintering pressure of 200 MPa. Heating and pressurization are performed simultaneously until the final target temperature and pressure are reached. Under these conditions, sintering is carried out at this temperature and pressure for 4 hours. Heating is then stopped, the load is removed, and the furnace is cooled to below 100°C before the vacuum is broken. The cladding is then removed, yielding a cylindrical blank.

[0038] The three-dimensional gradient structure multi-principal element alloy material prepared in this embodiment has a yield strength of 750 MPa, a tensile strength of 1218 MPa, and a fracture elongation of 30%, exhibiting excellent comprehensive mechanical properties.

[0039] Example 2

[0040] A method for preparing a three-dimensional gradient structure multi-principal element alloy material includes the following steps:

[0041] Step 1: Mixing and processing of multi-principal element alloy powder with reinforcing phase powder

[0042] Multi-principal component alloy powder, TiB2, and TiC powder were thoroughly mixed in a V-type mixer. The multi-principal component alloy powder was a spherical powder prepared by gas atomization or rotating electrode method, with an average particle size of 100 μm, and its specific composition was (VCoNi). 100-X (AlTi) X Where X represents the atomic percentage, X = 10; the atomic content of each of V, Co, and Ni is 30%, and Al and Ti are in equiatomic ratio. The average size of TiB2 powder is 500 nm, accounting for 1% by mass; the average size of TiC powder is 800 nm, accounting for 1% by mass; the mixing speed is 60 rpm, and the mixing time is 1 hour. To prevent powder oxidation during the mixing process, mixing is carried out in a protective atmosphere.

[0043] Step 2: Mixed powder airflow milling

[0044] The mixed powder was added to a dedicated air jet mill jar for impact deformation treatment. Argon gas with an oxygen content of less than 5 ppm was used as the impact gas source, the gas pressure was adjusted to 1.0 MPa, the feeding rate was 0.25 g / s, and the air jet mill cycle was 20 times. Finally, spherical powders uniformly coated with multi-principal element alloys by TiB2 and TiC powders were obtained. All the above operations were carried out in a glove box with a protected atmosphere to prevent oxidation.

[0045] Step 3: Degassing treatment with a protective casing

[0046] The mixed powder is placed in a stainless steel enclosure and subjected to high-temperature degassing at 400℃. The vacuum level inside the enclosure is better than 5×10⁻⁶. -3 After Pa, the sleeve is sealed by welding.

[0047] Step 4: Hot isostatic pressing and sintering

[0048] The cladding is placed in a hot isostatic pressing furnace for sintering. It is heated to 900°C at a heating rate of 50°C / min, while pressure is applied uniformly in all directions to a sintering pressure of 200 MPa. Heating and pressurization are performed simultaneously until the final target temperature and pressure are reached. Under these conditions, sintering is carried out at this temperature and pressure for 4 hours. Heating is then stopped, the load is removed, and the furnace is cooled to below 100°C before the vacuum is broken. The cladding is then removed, yielding a cylindrical blank.

[0049] The three-dimensional gradient structure multi-principal element alloy material prepared in this embodiment has a yield strength of 930 MPa, a tensile strength of 1268 MPa, and a fracture elongation of 21%, exhibiting excellent comprehensive mechanical properties.

[0050] Example 3

[0051] A method for preparing a three-dimensional gradient structure multi-principal element alloy material mainly includes the following steps:

[0052] Step 1: Mixing and processing of multi-principal element alloy powder with reinforcing phase powder

[0053] Multi-principal component alloy powder, TiB2, and TiC powder were thoroughly mixed in a V-type mixer. The multi-principal component alloy powder was a spherical powder prepared by gas atomization or rotating electrode method, with an average particle size of 100 μm, and its specific composition was (VCoNi). 100-X (AlTi) X Where X represents the atomic percentage, X = 10; the atomic content of each of V, Co, and Ni is 30%, and Al and Ti are in equiatomic ratio. The average size of TiB2 powder is 500 nm, accounting for 1.5% by mass; the average size of TiC powder is 800 nm, accounting for 1.5% by mass; the mixing speed is 60 rpm, and the mixing time is 1 hour. To prevent powder oxidation during the mixing process, mixing is carried out in a protective atmosphere.

[0054] Step 2: Mixed powder airflow milling

[0055] The mixed powder was added to a dedicated air jet mill jar for impact deformation treatment. Argon gas with an oxygen content of less than 5 ppm was used as the impact gas source, the gas pressure was adjusted to 1.0 MPa, the feeding rate was 0.25 g / s, and the air jet mill cycle was 20 times. Finally, spherical powders uniformly coated with multi-principal element alloys by TiB2 and TiC powders were obtained. All the above operations were carried out in a glove box with a protected atmosphere to prevent oxidation.

[0056] Step 3: Degassing treatment with a protective casing

[0057] The mixed powder is placed in a stainless steel enclosure and subjected to high-temperature degassing at 400℃. The vacuum level inside the enclosure is better than 5×10⁻⁶. -3 After Pa, the sleeve is sealed by welding.

[0058] Step 4: Hot isostatic pressing and sintering

[0059] The cladding is placed in a hot isostatic pressing furnace for sintering. It is heated to 1000°C at a heating rate of 50°C / min, while pressure is applied uniformly in all directions to the cladding. The sintering pressure is 200 MPa. Heating and pressurization are carried out simultaneously until the final target temperature and pressure are reached. Under these conditions, sintering is carried out at this temperature and pressure for 4 hours. Then, heating is stopped, the load is removed, and the furnace is cooled to below 100°C before the vacuum is broken. The cladding is then removed to obtain a cylindrical blank.

[0060] The three-dimensional gradient structure multi-principal element alloy material prepared in this embodiment has a yield strength of 1060 MPa, a tensile strength of 1370 MPa, and a fracture elongation of 10%, exhibiting excellent comprehensive mechanical properties.

[0061] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0062] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0063] In this invention, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" refers to two or more unless otherwise expressly defined.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a three-dimensional gradient structure multi-principal element alloy material, characterized in that, The process includes the following steps: Step S1: Mixing the multi-principal element alloy powder with the reinforcing phase powder to obtain a mixed powder; the composition of the multi-principal element alloy powder is (VCoNi). 100-X (AlTi) X Where X is the atomic percentage, ； The atomic content of each element V, Co, and Ni is 20-40%, and the reinforcing phase powder includes TiB2 powder and TiC powder; in the mixed powder, the mass fraction of TiB2 powder is 0.5-2.5%, the mass fraction of TiC powder is 0.5-2.5%, and the remainder is multi-principal element alloy powder; the multi-principal element alloy powder is prepared by gas atomization or rotating electrode method, with an average particle size of 50-150 μm, the average size of TiB2 powder is less than 1 μm, and the average size of TiC powder is less than 1 μm; Step S2: The mixed powder is subjected to air jet milling to obtain spherical powder in which the reinforcing phase powder uniformly coats the multi-principal element alloy powder; Step S3: The spherical powder is subjected to degassing treatment with a cladding; Step S4: The cladding is placed in a hot isostatic pressing furnace for hot isostatic pressing sintering.

2. The preparation method according to claim 1, characterized in that, The mixing process in step S1 is carried out in a protective atmosphere, with a mixing speed of 30-60 rpm and a mixing time of 1-2 hours.

3. The preparation method according to claim 1, characterized in that, In the air jet milling process of step S2, argon gas with an oxygen content of less than 5 ppm is used as the impingement airflow source, the airflow pressure is 1.0~1.5 MPa, the feeding speed is 0.12~0.25 g / s, and the air jet mill cycle is 5~20 times.

4. The preparation method according to claim 1, characterized in that, The air jet milling process in step S2 is carried out in a glove box with a protective atmosphere.

5. The preparation method according to claim 1, characterized in that, Step S3 specifically includes: the obtained spherical powder is placed into a casing for degassing treatment at a temperature of 400~500℃, and the vacuum degree inside the casing is better than 5×10⁻⁶. -3 After Pa, the sleeve is sealed by welding.

6. The preparation method according to claim 1, characterized in that, In the hot isostatic pressing sintering of step S4, the temperature is raised to 900-1100°C at a heating rate of 10-50°C / min, the sintering pressure is 200MPa, and the sintering time is 2-4 hours.

7. A three-dimensional gradient structure multi-principal element alloy material obtained by the preparation method according to any one of claims 1-6, characterized in that, It is composed of nano-scale TiB2 reinforcing phase, nano-scale TiC reinforcing phase and VCoNiAlTi alloy. The surface grains of the VCoNiAlTi alloy are submicron-scale and the core grains are micron-scale. The nano-scale TiB2 reinforcing phase and nano-scale TiC reinforcing phase periodically encapsulate the VCoNiAlTi alloy.

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