A precipitation-strengthened multi-principal element alloy and a method of making the same

Abstract

The application discloses a precipitation phase reinforced multi-principal element alloy and a preparation method thereof. The multi-principal element alloy is composed of at least three elements in tungsten, chromium, vanadium and iron elements, and has a rich-tungsten BCC structure precipitation strengthening phase. The precipitation phase reinforced multi-principal element alloy has high strength, high hardness and excellent plasticity.

Description

Technical Field

[0001] This invention relates to the field of advanced metal preparation technology, specifically to a precipitation-strengthened multi-principal-element alloy and its preparation method. Background Technology

[0002] Traditional alloys primarily use one or two metallic elements as the main components, and their properties are optimized by controlling trace elements. In recent years, multi-principal element alloys, which generally contain three or more elements, each of which is a principal component, have attracted widespread attention due to their superior mechanical properties. Because of severe lattice distortion and cocktail effects, multi-principal element alloys with refractory elements as the main components can exhibit excellent strength and high-temperature performance, showing promising prospects for engineering applications.

[0003] With the development of my country's new generation of technologies, the requirements for material performance in high-end equipment are further increasing. Given that traditional nickel-based superalloys can no longer meet the aerospace industry's demands for high-temperature resistant materials, the development of novel multi-principal element alloys with refractory elements as the main components is of great significance to the industry's development. Currently, the mechanical properties of multi-principal element alloys exhibit a trade-off effect, meaning it is difficult for alloys to simultaneously achieve high strength and excellent ductility. Therefore, the design and fabrication of multi-principal element alloys with high strength, high hardness, and excellent ductility remain highly challenging. Summary of the Invention

[0004] Based on the problems existing in the prior art, the present invention provides a precipitation-strengthened multi-principal alloy and its preparation method, aiming to enable the obtained multi-principal alloy to simultaneously possess high strength, high hardness and good plasticity.

[0005] To achieve its objectives, the present invention employs the following technical solution:

[0006] A precipitation-strengthened multi-principal-element alloy, characterized in that: the multi-principal-element alloy is composed of at least three elements selected from tungsten, chromium, vanadium, and iron, possesses a tungsten-rich BCC structure (cubic structure of the system) precipitation-strengthened phase, and exhibits high strength (yield strength > 1200 MPa) and high hardness (Vickers hardness > 700 kgf / mm²). 2 It also has excellent plasticity (fracture plasticity >25%).

[0007] Preferably, the precipitation-strengthened multi-principal-element alloy system of the present invention is FeVCrW, in order to obtain a dendritic structure with elemental segregation, so that the alloy has excellent plasticity.

[0008] Furthermore, in order to obtain the precipitation strengthening phase, the present invention utilizes an in-situ generation method to increase the content of elements abundant in dendrites or between dendrites, in order to obtain the precipitation strengthening phase.

[0009] Preferably, the element controlled in this invention is W, and other main elements have an equal atomic ratio, in order to obtain a hard tungsten-rich BCC structure precipitated strengthening phase, giving the alloy high strength and high hardness. The atomic ratio of tungsten is between 15 at.% and 20 at.%.

[0010] The method for preparing precipitate-strengthened multi-principal-element alloys according to the present invention includes the following steps:

[0011] Step 1: Take tungsten, chromium, vanadium and iron with a purity of 99.9 wt.% as metal raw materials, remove the oxide layer on the metal surface, ultrasonically clean and dry them, and weigh them according to the ratio, with the mass accurate to ±0.001g.

[0012] Step 2: Place the prepared metal raw materials into the crucible of the vacuum arc melting equipment in the order of low melting point elements at the bottom and high melting point elements at the top. Evacuate the equipment and then fill it with argon gas as a protective gas.

[0013] Step 3: Before melting the alloy ingot, melt the titanium ingot for 2 minutes to consume the residual oxygen in the furnace. Then, move the melting lance to the alloy ingot crucible to melt the alloy ingot with a current of 240-300A. After each melting, flip the alloy ingot over and place it against the inner wall of the crucible. The next melting will start from the top of the alloy ingot and slowly melt it, allowing the molten alloy to flow to the bottom of the crucible to ensure uniform melting. The final product is a FeVCrW-based multi-principal element alloy ingot.

[0014] The beneficial effects of this invention are as follows:

[0015] 1. The multi-principal alloy with tungsten-rich BCC structure and precipitate strengthening proposed in this invention possesses high strength, high hardness, and good plasticity, exhibiting excellent comprehensive mechanical properties. For example, the multi-principal alloy (FeVCr) 85W15 demonstrates a yield strength of 1375 MPa, a fracture strength of 3682 MPa, a fracture plasticity of 39.1%, and a fracture plasticity of 701 kgf / mm². 2 The hardness of the multi-principal element alloy (FeVCr) 80W20 is as follows. It exhibits a yield strength of 1580 MPa, a fracture strength of 3345 MPa, a fracture plasticity of 28.4%, and a hardness of 829 kgf / mm². 2 The hardness.

[0016] 2. The multi-principal element alloy system of the present invention not only has excellent mechanical properties, but also has great application prospects in aerospace and nuclear energy fields due to the high melting point and low activation properties of the principal elements. Attached Figure Description

[0017] Figure 1 The room temperature compressive stress-strain curve of the (FeVCr)85W15 multi-principal element alloy obtained in Example 1 of this invention.

[0018] Figure 2 The image shows the XRD pattern of the (FeVCr)85W15 multi-principal element alloy obtained in Example 1 of this invention.

[0019] Figure 3 The room temperature compressive stress-strain curve of the (FeVCr)80W20 multi-principal element alloy obtained in Example 2 of this invention.

[0020] Figure 4 The XRD pattern of the (FeVCr)80W20 multi-principal element alloy obtained in Example 2 of this invention is shown. Detailed Implementation

[0021] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following content is merely illustrative and explanatory of the concept of the present invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not deviate from the inventive concept or exceed the scope defined by the claims, all of which should fall within the protection scope of the present invention.

[0022] Example 1

[0023] A precipitation-strengthened multi-principal element alloy, specifically with the chemical composition (FeVCr)85W15, contains 15 at.% tungsten and 28.33 at.% each of chromium, vanadium, and iron. It exhibits a dendritic structure, with tungsten-rich BCC-structured strengthening phases precipitating within the dendrites. The chemical compositions of the dendrites, interdendritic spaces, and precipitated phases are shown in Table 1.

[0024] Table 1. Chemical composition of each phase in (FeVCr)85W15

[0025]

[0026] The specific preparation steps for (FeVCr)85W15 multi-principal element alloy are as follows:

[0027] Step 1: Take tungsten, chromium, vanadium and iron with a purity of 99.9 wt.% as metal raw materials, remove the surface oxide layer, ultrasonically clean and dry them, and weigh them according to the ratio, with the mass accurate to ±0.001g.

[0028] Step 2: Place the prepared metal raw materials into the crucible of the vacuum arc melting equipment in the order of low melting point elements at the bottom and high melting point elements at the top. Evacuate the equipment and then fill it with argon gas as a protective gas.

[0029] Step 3: Before melting the alloy ingot, melt the titanium ingot for 2 minutes to consume any residual oxygen in the furnace. Then, move the melting lance to the alloy ingot crucible to melt the ingot with a current of 260A. After each melting, flip the alloy ingot over and place it against the inner wall of the crucible. The next melting will start from the top of the alloy ingot and slowly melt it, allowing the molten alloy to flow to the bottom of the crucible to ensure uniform melting. The final product is a (FeVCr)85W15 series multi-principal element alloy ingot.

[0030] Figure 1 This is the room temperature compressive stress-strain curve of the (FeVCr)85W15 multi-principal element alloy obtained in this embodiment. Tests showed that the (FeVCr)85W15 obtained in this embodiment has a yield strength of 1375 MPa, a fracture strength of 3682 MPa, and a plastic deformation of 39.1% at room temperature. This multi-principal element alloy possesses high strength and plasticity, as well as a high Vickers hardness of 701 kgf / mm². 2 .

[0031] Figure 2 The XRD pattern of the (FeVCr)85W15 multi-principal-element alloy obtained in this embodiment shows that the alloy has precipitated phases.

[0032] Example 2

[0033] A precipitate-strengthened multi-principal-element alloy, specifically with the chemical composition (FeVCr)80W20, contains 20 at.% tungsten and 26.67 at.% each of chromium, vanadium, and iron. It exhibits a dendritic structure, with tungsten-rich BCC-structured strengthening phases precipitating within the dendrites. The chemical compositions of the dendrites, interdendritic spaces, and precipitates are shown in Table 2.

[0034] Table 2. Chemical composition of each phase in (FeVCr)80W20

[0035]

[0036] The specific preparation steps for (FeVCr)80W20 multi-principal element alloy are as follows:

[0037] Step 1: Take tungsten, chromium, vanadium and iron with a purity of 99.9 wt.% as metal raw materials, remove the surface oxide layer, ultrasonically clean and dry them, and weigh them according to the ratio, with the mass accurate to ±0.001g.

[0038] Step 2: Place the prepared metal raw materials into the crucible of the vacuum arc melting equipment in the order of low melting point elements at the bottom and high melting point elements at the top. Evacuate the equipment and then fill it with argon gas as a protective gas.

[0039] Step 3: Before melting the alloy ingot, melt the titanium ingot for 2 minutes to consume any residual oxygen in the furnace. Then, move the melting lance to the alloy ingot crucible to melt the ingot with a current of 280A. After each melting, flip the alloy ingot over and place it against the inner wall of the crucible. The next melting will start from the top of the alloy ingot and slowly melt it, allowing the molten alloy to flow to the bottom of the crucible to ensure uniform melting. The final product is a (FeVCr)80W20 series multi-principal element alloy ingot.

[0040] Figure 3 This is the room temperature compressive stress-strain curve of the (FeVCr)80W20 multi-principal element alloy obtained in this embodiment. Tests showed that the (FeVCr)80W20 obtained in this embodiment has a yield strength of 1580 MPa, a fracture strength of 3345 MPa, and a plastic deformation of 28.4% at room temperature. This multi-principal element alloy possesses high strength and plasticity, as well as a high Vickers hardness of 829 kgf / mm². 2 .

[0041] Figure 4 The XRD pattern of the (FeVCr)80W20 multi-principal-element alloy obtained in this embodiment shows that the alloy has precipitated phases.

[0042] Table 3 compares and presents the mechanical property data of the multi-principal alloys obtained in Examples 1 and 2 of the present invention.

[0043] Table 3 Mechanical properties of (FeVCr)85W15 and (FeVCr)80W20

[0044]

[0045] Compared with Example 1, from Appendix Figure 4 As can be seen from the peak intensity of the precipitated phase, the multi-principal element alloy of Example 2 has a larger volume of precipitated phase, significantly improving yield strength and hardness, while still maintaining considerable plasticity, resulting in excellent comprehensive mechanical properties.

[0046] The above are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A precipitation-strengthened multi-principal-element alloy, characterized in that: The multi-principal alloy has a tungsten-rich BCC structure precipitated strengthening phase. The multi-principal alloy is composed of four elements: tungsten, chromium, vanadium, and iron. The atomic ratios of chromium, vanadium, and iron are equal, and the atomic ratio of tungsten is between 15 at.% and 20 at.%.

2. The precipitation-strengthened multi-principal-element alloy according to claim 1, characterized in that: The multi-principal element alloy has a yield strength > 1200 MPa and a Vickers hardness > 700 kgf / mm². 2 Fracture plasticity > 25%.

3. A method for preparing the multi-principal element alloy according to any one of claims 1 to 2, characterized in that, Includes the following steps: Step 1: Take tungsten, chromium, vanadium and iron as metal raw materials, remove the oxide layer on the metal surface, ultrasonically clean and dry them, and weigh them according to the ratio; Step 2: Place the prepared metal raw materials into the crucible of the vacuum arc melting equipment in the order of low melting point elements at the bottom and high melting point elements at the top. Evacuate the equipment and then fill it with argon gas as a protective gas. Step 3: Before melting the alloy ingot, melt the titanium ingot for 2 minutes to consume the residual oxygen in the furnace; then, move the melting gun to the alloy ingot crucible to melt the alloy ingot with a current of 240-300 A; after each melting, turn the alloy ingot over and lean it against the inner wall of the crucible. The next melting will start from the top of the alloy ingot, allowing the alloy liquid to flow to the bottom of the crucible to ensure uniform alloy melting, and finally obtain the FeVCrW system multi-principal element alloy ingot.

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