High-temperature oxidation-resistant refractory high-entropy alloy and preparation method thereof
By optimizing the composition and content of Al, Mo, Nb, Ta, and Ti, a high-temperature oxidation-resistant refractory high-entropy alloy with a BCC single-phase structure was prepared, solving the problem of easy oxidation of refractory high-entropy alloys at high temperatures and achieving excellent oxidation resistance and mechanical properties at high temperatures.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHONGQING UNIV
- Filing Date
- 2025-08-07
- Publication Date
- 2026-05-19
AI Technical Summary
Existing refractory high-entropy alloys are prone to oxidation at high temperatures, exhibiting poor oxidation resistance, which limits their industrial application in aerospace and other fields.
A high-temperature oxidation-resistant refractory high-entropy alloy was prepared by laser direct deposition using an alloy with Al, Mo, Nb, Ta and Ti as the main components. The alloy contained 36-42 at of Al, 8-12 at of Mo, 15-20 at of Nb and Ta, and 15-20 at of Ti, forming a BCC single-phase structure and an α-Al2O3 protective layer to improve its oxidation resistance.
The alloy possesses excellent high-temperature oxidation resistance and mechanical properties, significantly improving the ductility and overall performance of the material, and effectively preventing oxygen diffusion in high-temperature environments.
Smart Images
Figure CN120989476B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of alloy materials, and particularly relates to a high-temperature oxidation-resistant refractory high-entropy alloy and its preparation method. Background Technology
[0002] In the aviation field, the performance and safety of aircraft are highly dependent on the materials and structures of their components. With the development of the aviation industry, high-temperature components in new aircraft face even higher operating temperatures, thus necessitating the development of a new material system applicable to these components. High-entropy alloys, composed of five or more elements in equimolar ratios, possess excellent physical, chemical, and mechanical properties, such as high strength, high hardness, high corrosion resistance, and high-temperature stability. The concept of refractory high-entropy alloys primarily involves high-melting-point refractory elements, which can maintain the structural strength and stability of the alloy under high-temperature conditions, resisting high-temperature oxidation and thermal expansion. Introducing refractory high-entropy alloys into the aviation field allows aircraft to operate in higher-temperature and more demanding environments, improving overall performance and reliability.
[0003] MoNbTaW refractory high-entropy alloys are a class of alloys composed of multiple transition metal elements such as Mo, Nb, Ta, and W. They possess excellent high-temperature yield strength and fracture toughness, maintaining stable mechanical properties under extreme environmental conditions. Therefore, they are considered potential materials for aerospace, nuclear energy, and other high-temperature engineering fields. However, promoting their industrial application still faces some challenges. For example, the constituent elements of this alloy are easily oxidized at high temperatures, exhibiting poor oxidation resistance. Summary of the Invention
[0004] In view of this, the purpose of the present invention is to provide a high-temperature oxidation-resistant refractory high-entropy alloy and its preparation method, wherein the alloy material has good high-temperature oxidation resistance.
[0005] This invention provides a high-temperature resistant, oxidation-resistant, refractory, high-entropy alloy, whose constituent elements are Al, Mo, Nb, Ta, and Ti. The content of Al in the alloy is 36-42 at, the content of Mo in the alloy is 8-12 at, the content of Nb in the alloy is 15-20 at, the content of Ta in the alloy is 15-20 at, and the content of Ti in the alloy is 15-20 at.
[0006] Preferably, the Al content in the alloy is 39 at%.
[0007] Preferably, the Mo content in the alloy is 10 at%.
[0008] Preferably, the Nb content in the alloy is 17 at%.
[0009] Preferably, the Ta content in the alloy is 17 at%.
[0010] Preferably, the Ti content in the alloy is 17 at%.
[0011] This invention provides a method for preparing the high-temperature oxidation-resistant refractory high-entropy alloy described in the above technical solution, comprising the following steps:
[0012] a) Mix Al powder, Mo powder, Nb powder, Ta powder and Ti powder according to the specified ratio to obtain a mixed powder;
[0013] b) The mixed powder is deposited onto the substrate using a laser direct deposition process, and the resulting deposition layer is a high-temperature oxidation-resistant refractory high-entropy alloy.
[0014] Preferably, the mixed powder is dried before deposition.
[0015] Preferably, the substrate is TC4 titanium alloy.
[0016] Preferably, the substrate undergoes surface impurity removal and preheating before participating in deposition.
[0017] Compared with existing technologies, this invention provides a high-temperature oxidation-resistant refractory high-entropy alloy and its preparation method. The high-temperature oxidation-resistant refractory high-entropy alloy provided by this invention comprises Al, Mo, Nb, Ta, and Ti, with Al content ranging from 36 to 42 at%, Mo content ranging from 8 to 12 at%, Nb content ranging from 15 to 20 at%, Ta content ranging from 15 to 20 at%, and Ti content ranging from 15 to 20 at%. By optimizing the composition and content of each element, this invention enables the alloy system to possess a BCC single-phase structure and a low valence electron concentration (VEC). The BCC phase structure exhibits excellent mechanical properties and high-temperature stability, while the low valence electron concentration contributes to improved ductility and overall material properties. Furthermore, the high Al content in the alloy can form an α-Al₂O₃ protective layer during the initial oxidation stage, which effectively prevents oxygen diffusion at high temperatures, significantly improving the alloy's oxidation resistance. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0019] Figure 1 This is the X-ray diffraction pattern of the 39Al-10Mo-51(NbTaTi) refractory high-entropy alloy provided in Example 1 of this invention;
[0020] Figure 2 The figure shows the oxidation test results of the 39Al-10Mo-51(NbTaTi) refractory high-entropy alloy provided in Example 1 of the present invention; wherein, (a) is a graph showing the functional relationship between the mass gain of the high-entropy alloy and time at different temperatures, and (b) is a double logarithmic curve showing the functional relationship between the mass gain of the high-entropy alloy and time at different temperatures.
[0021] Figure 3 The image shows the microhardness test results of the 39Al-10Mo-51(NbTaTi) refractory high-entropy alloy provided in Example 1 of this invention. Detailed Implementation
[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0023] This invention provides a high-temperature resistant, oxidation-resistant, refractory, high-entropy alloy, whose constituent elements are Al, Mo, Nb, Ta, and Ti.
[0024] In the alloy provided by the present invention, the Al content in the alloy is 36-42 at, specifically 36 at%, 37 at%, 38 at%, 39 at%, 40 at%, 41 at%, or 42 at, with 39 at being the most preferred.
[0025] In the alloy provided by the present invention, the content of Mo in the alloy is 8 to 12 at, specifically 8 at%, 9 at%, 10 at%, 11 at%, or 12 at, with 10 at being the most preferred.
[0026] In the alloy provided by the present invention, the Nb content in the alloy is 15-20 at%, specifically 15 at%, 16 at%, 17 at%, 18 at%, 19 at%, or 20 at%, with 17 at being the most preferred.
[0027] In the alloy provided by the present invention, the content of Ta in the alloy is 15-20 at%, specifically 15 at%, 16 at%, 17 at%, 18 at%, 19 at%, or 20 at%, with 17 at being the most preferred.
[0028] In the alloy provided by the present invention, the content of Ti in the alloy is 15-20 at%, specifically 15 at%, 16 at%, 17 at%, 18 at%, 19 at%, or 20 at%, with 17 at being the most preferred.
[0029] In the alloy provided by this invention, the alloy with the optimal element content is designated as 39Al-10Mo-51(NbTaTi).
[0030] In the alloy provided by the present invention, the alloy has a BCC single-phase structure phase.
[0031] This invention also provides a method for preparing the high-temperature oxidation-resistant refractory high-entropy alloy described in the above technical solution, comprising the following steps:
[0032] a) Mix Al powder, Mo powder, Nb powder, Ta powder and Ti powder according to the specified ratio to obtain a mixed powder;
[0033] b) The mixed powder is deposited onto the substrate using a laser direct deposition process, and the resulting deposition layer is a high-temperature oxidation-resistant refractory high-entropy alloy.
[0034] In the preparation method provided by the present invention, in step a), the mixing speed is preferably 100-200 r / min, specifically 100 r / min, 110 r / min, 120 r / min, 130 r / min, 140 r / min, 150 r / min, 160 r / min, 170 r / min, 180 r / min, 190 r / min or 200 r / min, most preferably 200 r / min; the mixing time is preferably 6-24 h, specifically 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h or 24 h, most preferably 12 h.
[0035] In the preparation method provided by the present invention, in step a), the mixing is preferably carried out in a mixing tank; ceramic balls are preferably added to the mixing tank, and the volume ratio of the ceramic balls to the metal powder is preferably 1:(2-8), specifically 1:2, 1:3, 1:4, 1:5, 1:6, 1:7 or 1:8, with 1:5 being the most preferred.
[0036] In the preparation method provided by this invention, in step b), the mixed powder is preferably dried before deposition to ensure good powder flowability and improve the quality of the deposited layer. In this invention, the drying temperature is preferably 100–150°C, specifically 100°C, 110°C, 120°C, 130°C, 140°C, or 150°C, with 120°C being the most preferred. The drying time is preferably 1–5 hours, specifically 1 hour, 2 hours, 3 hours, 4 hours, or 5 hours, with 3 hours being the most preferred.
[0037] In the preparation method provided by the present invention, in step b), the substrate is preferably TC4 titanium alloy.
[0038] In the preparation method provided by this invention, in step b), the substrate is preferably subjected to surface cleaning and preheating before participating in deposition. In this invention, the surface cleaning process preferably includes sanding, cleaning, and drying; wherein the sanding is performed until the surface oxide layer and impurities are completely removed; the cleaning method is preferably ultrasonic cleaning in an alcohol solution; the drying temperature is preferably 100–200°C, specifically 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, or 200°C, with 150°C being the most preferred; the drying time is preferably 10–60 min, specifically 10 min, 20 min, 30 min, 40 min, 50 min, or 60 min, with 30 min being the most preferred. In this invention, the preheating temperature is preferably 250-350°C, specifically 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, or 350°C, with 300°C being the most preferred; the preheating time is preferably 5-40 minutes, specifically 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, or 40 minutes, with 20 minutes being the most preferred.
[0039] In the preparation method provided by this invention, in step b), the laser power during deposition is preferably 200-800W, specifically 200W, 300W, 400W, 500W, 600W, 700W, or 800W, with 500W being the most preferred; the laser spot diameter during deposition is preferably 1-3mm, specifically 1mm, 1.2mm, 1.5mm, 1.7mm, 2mm, 2.3mm, 2.5mm, 2.7mm, or 3mm, with 2mm being the most preferred; the powder feed rate during deposition is preferably 0.1-0.5L / min, specifically 0.1L / min, 0.2L / min, 0.3L / min, 0.4L / min, or 0.5L / min, with 0.2L / min being the most preferred; the nozzle lifting height during deposition is preferably 0.1-0.5L / min. The nozzle height is 0.5 mm, specifically 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm, with 0.3 mm being the most preferred. The nozzle lifting height refers to the vertical lifting distance of the nozzle after each layer of material is deposited during the layer-by-layer deposition process. The overlap rate during deposition is preferably 40% to 60%, specifically 40%, 45%, 50%, 55%, or 60%, with 50% being the most preferred. The overlap rate refers to the degree of overlap between adjacent deposition paths or laser spots during laser deposition. The protective gas introduced during deposition is preferably nitrogen and / or argon. The flow rate of the protective gas during deposition is preferably 5 to 30 L / min, specifically 5 L / min, 10 L / min, 15 L / min, 20 L / min, 25 L / min, or 30 L / min, with 15 L / min being the most preferred.
[0040] The technical solution provided by this invention optimizes the composition and content of the alloy elements, enabling the alloy system to possess a BCC single-phase structure and a low valence electron concentration (VEC). The BCC phase structure exhibits excellent mechanical properties and high-temperature stability, while the low valence electron concentration contributes to improved ductility and overall material properties. Furthermore, the high Al content in the alloy can form an α-Al₂O₃ protective layer during the initial oxidation stage, which effectively prevents oxygen diffusion at high temperatures, significantly enhancing the alloy's oxidation resistance.
[0041] For clarity, the following examples will be used to provide a detailed description.
[0042] Example 1
[0043] Metal powders with Al content of 39 at%, Mo content of 10 at%, Nb content of 17 at%, Ta content of 17 at%, and Ti content of 17 at were weighed using an electronic balance and mixed in a beaker.
[0044] The powder mixing equipment and ceramic balls were cleaned with anhydrous ethanol, then rinsed and dried with deionized water. The mixed powder and ceramic balls were then placed in a mixing tank at a volume ratio of 5:1 and sealed. The mixing device was set to rotate at 200 rpm and the mixing time was set to 12 hours.
[0045] Remove the mixed powder from the mixing tank and place it in a beaker, then put it in a drying device. Set the drying device temperature to 120℃ and the time to 3 hours. After drying, place the powder in a sealed bag and vacuum-seal it in a sealed container.
[0046] Using TC4 titanium alloy as the substrate, the substrate was sanded until the surface oxide layer and impurities were completely removed. The sanded substrate was then thoroughly cleaned with an alcohol solution in an ultrasonic cleaner. After cleaning, the substrate was placed in a drying oven for rapid drying at 150℃ for 30 minutes. The dried substrate was then placed in a sealed bag and sealed in a vacuum container for storage.
[0047] The sealed powder and substrate were removed from the sealed container. The powder was placed into a powder feeding container and sealed. The substrate was preheated in a vacuum furnace at 300°C for 20 minutes. A laser direct deposition process was used, with the laser power set to 500W, spot diameter to 2mm, powder feed rate to 0.2L / min, nozzle lift height to 0.3mm, overlap ratio to 50%, and protective gas (argon) flow rate to 15L / min, to deposit 39Al-10Mo-51 (NbTaTi) refractory high-entropy alloy material on the titanium alloy surface.
[0048] The deposited samples were cut and polished for subsequent characterization and testing.
[0049] The X-ray diffraction test was performed on the sample prepared in this embodiment, and the results are as follows: Figure 1 As shown, Figure 1 This is the X-ray diffraction pattern of the 39Al-10Mo-51(NbTaTi) refractory high-entropy alloy provided in Embodiment 1 of the present invention. Figure 1 It can be seen that the alloy has a single-phase BCC structure.
[0050] An oxidation test was conducted on the sample prepared in this embodiment. The test was performed in a hot vacuum furnace at a temperature of 1000–1200°C for 12 hours. The oxidation test results are as follows: Figure 2 As shown, Figure 2The figures shown are oxidation test results of the 39Al-10Mo-51(NbTaTi) refractory high-entropy alloy provided in Example 1 of this invention. (a) is a graph showing the function relationship between the mass gain of the high-entropy alloy and time at different temperatures, and (b) is a double logarithmic curve showing the function relationship between the mass gain of the high-entropy alloy and time at different temperatures. The oxidation test results show that the alloy has excellent oxidation resistance at 1000℃, with a weight gain of only 5.9 mg / cm³ after 10 hours of oxidation. 2 .
[0051] The microhardness test was performed on the sample prepared in this embodiment, and the results are as follows: Figure 3 As shown, Figure 3 This is a microhardness result diagram of the 39Al-10Mo-51(NbTaTi) refractory high-entropy alloy provided in Example 1 of this invention. Figure 3 It can be seen that the alloy has high hardness at room temperature, with an average microhardness of 486.35 HV.
[0052] Example 2
[0053] Referring to Example 1, the only difference is that the Al content is adjusted to 36 at%, the Mo content to 8 at%, the Nb content to 18.6 at%, the Ta content to 18.7 at%, and the Ti content to 18.7 at%.
[0054] An oxidation test was conducted on the sample prepared in this embodiment. The results showed that the alloy gained more weight at 1000℃ than that in Example 1.
[0055] Microhardness tests were performed on the samples prepared in this embodiment, and the results showed that the microhardness of the alloy was lower than that of Example 1.
[0056] Example 3
[0057] Referring to Example 1, the only difference is that the Al content is adjusted to 42 at%, the Mo content to 12 at%, the Nb content to 15.3 at%, the Ta content to 15.3 at%, and the Ti content to 15.4 at%.
[0058] An oxidation test was conducted on the sample prepared in this embodiment. The results showed that the alloy gained more weight at 1000℃ than that in Example 1.
[0059] Microhardness tests were performed on the samples prepared in this embodiment, and the results showed that the microhardness of the alloy was lower than that of Example 1.
[0060] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A high-temperature oxidation-resistant refractory high-entropy alloy, characterized in that, The alloy is composed of Al, Mo, Nb, Ta, and Ti, wherein the content of Al in the alloy is 36-42 at, the content of Mo in the alloy is 8-12 at, the content of Nb in the alloy is 15-20 at, the content of Ta in the alloy is 15-20 at, and the content of Ti in the alloy is 15-20 at.
2. The high-temperature oxidation-resistant refractory high-entropy alloy according to claim 1, characterized in that, The Al content in the alloy is 39 at%.
3. The high-temperature oxidation-resistant refractory high-entropy alloy according to claim 1, characterized in that, The Mo content in the alloy is 10 at%.
4. The high-temperature oxidation-resistant refractory high-entropy alloy according to claim 1, characterized in that, The Nb content in the alloy is 17 at%.
5. The high-temperature oxidation-resistant refractory high-entropy alloy according to claim 1, characterized in that, The Ta content in the alloy is 17 at%.
6. The high-temperature oxidation-resistant refractory high-entropy alloy according to claim 1, characterized in that, The Ti content in the alloy is 17 at%.
7. A method for preparing a high-temperature oxidation-resistant refractory high-entropy alloy according to any one of claims 1 to 6, characterized in that, Includes the following steps: a) Mix Al powder, Mo powder, Nb powder, Ta powder and Ti powder according to the specified ratio to obtain a mixed powder; b) The mixed powder is deposited onto the substrate using a laser direct deposition process, and the resulting deposition layer is a high-temperature oxidation-resistant refractory high-entropy alloy.
8. The preparation method according to claim 7, characterized in that, The mixed powder is dried before deposition.
9. The preparation method according to claim 7, characterized in that, The substrate is TC4 titanium alloy.
10. The preparation method according to claim 7, characterized in that, The substrate undergoes surface impurity removal and preheating before participating in deposition.