A method for depositing Dy and Hf modified AlCoCrFeNi high entropy alloy films to improve the oxidation resistance of TiAl alloys

Abstract

The present application discloses a method for depositing Dy and Hf modified AlCoCrFeNi high entropy alloy films to improve the oxidation resistance of TiAl alloys, which relates to the field of high entropy alloy film preparation. The method comprises the following steps: using Ti, Al, and Nb as synthetic raw materials, and utilizing vacuum non-consumable arc melting technology to prepare a Ti‑45Al‑8Nb substrate; S2, weighing pure metal raw materials Al, Co, Cr, Fe, Ni and pure active raw materials Dy and Hf, and utilizing vacuum non-consumable arc melting technology to prepare a modified AlCoCrFeNi high entropy alloy target; S3, installing the Ti‑45Al‑8Nb substrate in step S1 on a fixture of a magnetron sputtering device, placing the modified AlCoCrFeNi high entropy alloy target in step S2 on a radio frequency target, and utilizing magnetron sputtering technology to obtain a TiAl alloy covered with the modified AlCoCrFeNi high entropy alloy film. Therefore, the present application adopts the above-mentioned method of depositing Dy and Hf modified AlCoCrFeNi high entropy alloy film to improve the oxidation resistance of TiAl alloy, and the obtained modified AlCoCrFeNi high entropy alloy film improves the oxidation resistance of TiAl alloy.

Description

Technical Field

[0001] The present application relates to the field of high entropy alloy film preparation, and more particularly to a method for depositing Dy and Hf modified AlCoCrFeNi high entropy alloy films to improve the oxidation resistance of TiAl alloys. Background Art

[0002] TiAl alloys have the advantages of low density, high specific strength at high temperatures, and good creep resistance, making them promising for use in aircraft engines. As the thrust-to-weight ratio of aircraft engines continues to increase, the operating temperature of turbine blade materials is also increasing. It is well known that TiAl alloys form a non-protective mixture of TiO2 and Al2O3 at high temperatures, rather than a single, continuous Al2O3. Consequently, their poor high-temperature oxidation resistance limits their application. Adding elements such as niobium, tungsten, and silicon appears to enhance the high-temperature oxidation resistance of TiAl alloys, but this often degrades their mechanical properties. Therefore, a protective coating is needed to improve the high-temperature oxidation resistance of TiAl alloys. MCrAlY (M = Ni, Co, or both) cladding coatings can protect TiAl alloys from oxidation at high temperatures. However, MCrAlY coatings have limitations in terms of compatibility with TiAl alloys. Severe interdiffusion between the TiAl alloy substrate and the MCrAlY coating can lead to the formation of brittle phases and internal oxidation, which reduces the coating's adhesion and ultimately leads to premature failure. Therefore, it is necessary to develop an oxidation-resistant coating with good compatibility with the TiAl alloy substrate.

[0003] The concept of high-entropy alloys (HEAs) was proposed by Ye and Cantor in 2004. HEAs are typically composed of at least five elements in equal or nearly equal atomic percentages. The unique structure and excellent properties of HEAs are attributed to four key effects: high entropy, severe lattice distortion, retarded diffusion, and the cocktail effect. High mixing entropy gives HEAs simple solid solution structures, such as face-centered cubic (FCC), body-centered cubic (BCC), or hexagonal close-packed (HCP), rather than complex alloys. Consequently, HEAs exhibit excellent high-temperature strength, oxidation resistance, and corrosion resistance, making them promising materials for high-temperature protective coatings. Dong et al. fabricated an AlCoCrFeNi2.1Tix coating on a Ti-6Al-4V alloy using spark plasma sintering. They found that a dense oxide film composed of aluminum oxide and a small amount of chromium oxide formed on the surface of the Ti-6Al-4V alloy, hindering the inward diffusion of oxygen and improving the oxidation resistance of the Ti-6Al-4V alloy at 800°C. Zhang et al. fabricated an AlCoCrFeNiSix high-entropy alloy coating on a 316L stainless steel substrate using a vapor plasma spray method. Oxidation tests at 800°C demonstrated that the appropriate addition of Si could improve the oxidation resistance of the high-entropy alloy coating, making it promising for use as a bond coat for thermal barrier coatings. Chang et al. fabricated a FeCrxCoNiB coating on an AISI1045 steel substrate using laser cladding and investigated its oxidation resistance at 900°C. They found that when x ≥ 2, the coating exhibited excellent oxidation resistance due to the formation of a continuous and dense Cr2O3 oxide film. Among all high-entropy alloys, the AlCoCrFeNi system possesses a unique microstructure and excellent mechanical properties, making it an ideal candidate for high-temperature protective coatings. However, AlCoCrFeNi exhibits poor oxidation resistance at high temperatures due to the presence of spinel or mixed oxides in the oxide, which accelerates the extensive spalling of the oxide layer.

[0004] It is well known that small amounts of reactive elements (REs, such as Dy and Hf) can enhance the high-temperature oxidation resistance of alloys and coatings by improving the adhesion of the oxide layer. Feng et al. reported that Dy doping can improve the oxidation resistance of Al-Si coatings because the stronger Dy-O bond increases the adhesion energy of the oxide layer. In addition, several studies have shown that Hf doping can inhibit the inward diffusion of oxygen and form Hf-rich "pinning" oxides at the interface between the oxide layer and the substrate, thereby improving the adhesion of the oxide layer. Currently, high-entropy alloy coatings are commonly prepared by processes such as laser cladding, thermal spraying, magnetron sputtering, and electrochemical deposition. Among these technologies, magnetron sputtering has attracted increasing attention due to its advantages such as high deposition rate, dense film structure, and controllable film thickness.

[0005] Therefore, it is an urgent technical problem to modify the AlCoCrFeNi high entropy alloy with active elements Dy and Hf and further improve the oxidation resistance of TiAl alloy by improving the adhesion performance of the oxide layer. Summary of the Invention

[0006] The purpose of this application is to provide a method for depositing Dy and Hf modified AlCoCrFeNi high entropy alloy films to improve the oxidation resistance of TiAl alloys, thereby improving the oxidation resistance of TiAl alloys.

[0007] The present application provides a method for depositing a Dy and Hf modified AlCoCrFeNi high entropy alloy film to improve the oxidation resistance of a TiAl alloy, comprising the following steps:

[0008] S1. Using Ti, Al and Nb as synthetic raw materials, a Ti-45Al-8Nb matrix was prepared using vacuum non-consumable arc melting technology;

[0009] S2. Weigh pure metal raw materials Al, Co, Cr, Fe, Ni and pure active raw materials Dy and Hf, and prepare a modified AlCoCrFeNi high entropy alloy target by using vacuum non-consumable arc melting technology;

[0010] S3. Mount the Ti-45Al-8Nb substrate in step S1 on a fixture of a magnetron sputtering device, place the modified AlCoCrFeNi high entropy alloy target in step S2 on a radio frequency target, and use magnetron sputtering technology to obtain a TiAl alloy covered with a modified AlCoCrFeNi high entropy alloy film.

[0011] Preferably, in step S3, the magnetron sputtering parameters are: the temperature of the Ti-45Al-8Nb substrate is 80-100°C, the power of the AlCoCrFeNi high entropy alloy target is 300W, the sputtering time is 7-8h, the pressure is 0.4Pa, and the vacuum degree is 1x10 -4 ~6x10 - 4 Pa.

[0012] Preferably, step S1 further includes the following steps:

[0013] 1) The prepared Ti-45Al-8Nb matrix was cut into samples using a wire cutting process, and the samples were polished with water-abrasive sandpaper and then polished to a mirror surface using a polishing machine;

[0014] 2) The Ti-45Al-8Nb substrate polished in step 1) is placed in an alcohol solution for ultrasonic cleaning at an ultrasonic frequency of 50 to 60 kHz for 10 to 20 minutes, and then dried in an oven at 80°C.

[0015] Preferably, step S2 further includes the following steps:

[0016] (1) The modified AlCoCrFeNi high entropy alloy target was cut by wire cutting and the surface oil was removed by sandpaper;

[0017] (2) The modified AlCoCrFeNi high entropy alloy target treated in step (1) is placed in an alcohol solution for ultrasonic cleaning at an ultrasonic frequency of 50 to 60 kHz for 10 to 20 minutes, and then placed in an oven at 80°C for drying.

[0018] Preferably, the doping amount of Dy and Hf in the modified AlCoCrFeNi high entropy alloy target is 0.01-0.03% at.

[0019] Preferably, in the modified AlCoCrFeNi high entropy alloy target, the atomic ratio of Al, Co, Cr, Fe and Ni is 1:1:1:1:1.

[0020] Preferably, in step 1), the sample is polished successively with 200#, 400#, 800#, 1000#, and 1200# water-abrasive sandpaper.

[0021] Preferably, the mass fraction of the alcohol solution is 85-99.9%.

[0022] Preferably, before weighing the pure metal raw materials Al, Co, Cr, Fe, Ni and the pure active raw materials Dy and Hf, the block, granular and flaky pure metal raw materials Al, Co, Cr, Fe, Ni and the pure active raw materials Dy and Hf are mechanically polished and ultrasonically cleaned in acetone or anhydrous ethanol to remove the oxide film and sediment impurities, and then placed in Nb foil in order from low to high melting point, wrapped together and placed at the bottom of a copper crucible for smelting.

[0023] Preferably, the vacuum is drawn to 4-5×10 -3 Pa, and filled with high-purity argon gas to 1.0×10 5 Pa is used for protection, and the raw materials are repeatedly melted 5-6 times under argon protection.

[0024] Therefore, the present application adopts the above-mentioned method of depositing Dy and Hf modified AlCoCrFeNi high entropy alloy film to improve the oxidation resistance of TiAl alloy, which has the following beneficial effects:

[0025] (1) The AlCoCrFeNi high entropy alloy film containing 0.02 at.% active elements Dy and Hf has a single-phase BCC columnar crystal structure with an average grain size of 21.1 nm;

[0026] (2) The oxide of the AlCoCrFeNi high entropy alloy film containing 0.02 at.% active elements Dy and Hf oxidized at 900℃ for 100h is protective Al2O3, and the oxidation weight gain is 0.81 mg·cm -2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the principle diagram of magnetron sputtering of this application;

[0028] Figure 2 : is a BSE cross-sectional view of the high entropy alloy film prepared in Example 1 of the present application and the content of each element at the point taken in the figure; wherein a is a BSE cross-sectional view of the high entropy alloy film prepared in Example 1, and b is the content of each element at the point taken in figure a;

[0029] Figure 3 is the GiXRD pattern of the high entropy alloy film prepared in Example 1;

[0030] Figure 4 This is the oxidation weight gain curve of the high-entropy alloy film prepared in the present application compared with the TiAl alloy oxidized at 900°C for 100h, wherein HEF1 is a Dy- and Hf-modified AlCoCrFeNi high-entropy alloy film, HEF2 is an unmodified AlCoCrFeNi high-entropy alloy film, HEF3 is a Dy-modified AlCoCrFeNi high-entropy alloy film, and HEF4 is an Hf-modified AlCoCrFeNi high-entropy alloy film. (a) is a relationship diagram of the oxidation weight gain per unit area and the oxidation time, and (b) is a fitting curve of the relationship between the oxidation weight gain per unit area and the square root of the oxidation time, which further indicates that the oxidation kinetics curve of the sample follows the parabolic law and is consistent with the classical oxidation theory. DETAILED DESCRIPTION

[0031] The present application provides a method for depositing a Dy and Hf modified AlCoCrFeNi high entropy alloy film to improve the oxidation resistance of a TiAl alloy, comprising the following steps:

[0032] S1. Using Ti, Al and Nb as synthetic raw materials, a Ti-45Al-8Nb matrix was prepared by vacuum non-consumable arc melting technology; the prepared Ti-45Al-8Nb matrix was cut into samples by wire cutting process, and the samples were polished with 200#, 400#, 800#, 1000# and 1200# water-abrasive sandpaper in sequence, and then polished to a mirror surface by a polishing machine; the polished Ti-45Al-8Nb matrix was then placed in an alcohol solution with a mass fraction of 85-99..9% for ultrasonic cleaning at an ultrasonic frequency of 50-60KHz and a ultrasonic cleaning time of 10-20min, and then placed in an 80°C oven for drying.

[0033] S2. Weigh pure metal raw materials Al, Co, Cr, Fe, Ni and pure active raw materials Dy and Hf, and prepare modified AlCoCrFeNi high entropy alloy targets by vacuum non-consumable arc melting technology; before weighing the raw materials, mechanically grind the block, granular and flaky raw materials and ultrasonically clean them in acetone or anhydrous ethanol to remove oxide films and sediment impurities, and then place them in Nb foil in the order of melting point from low to high, wrap them together and place them at the bottom of a copper crucible for melting, and evacuate the vacuum to 4-5×10 -3 Pa, and filled with high-purity argon gas to 1.0×10 5 Pa is used for protection, and the raw materials are repeatedly melted 5-6 times under argon protection to prepare a modified AlCoCrFeNi high entropy alloy target; the modified AlCoCrFeNi high entropy alloy target is cut by a wire cutting process, and the surface oil is polished off with water abrasive paper; the modified AlCoCrFeNi high entropy alloy target after degreasing is placed in an alcohol solution with a mass fraction of 85-99..9% for ultrasonic cleaning, the ultrasonic frequency is 50-60KHz, the cleaning time is about 10-20min, and then it is placed in an 80℃ oven for drying; the doping amount of Dy and Hf in the modified AlCoCrFeNi high entropy alloy target is 0.02%at; the atomic ratio of Al, Co, Cr, Fe and Ni in the modified AlCoCrFeNi high entropy alloy target is 1:1:1:1:1.

[0034] S3, the Ti-45Al-8Nb substrate in step S1 is mounted on a fixture of a magnetron sputtering device, the modified AlCoCrFeNi high entropy alloy target in step S2 is placed on a radio frequency target, and a TiAl alloy covered with a modified AlCoCrFeNi high entropy alloy film is obtained by magnetron sputtering technology; the magnetron sputtering parameters are: the temperature of the Ti-45Al-8Nb substrate is 80-100°C, the power of the AlCoCrFeNi high entropy alloy target is 300W, the sputtering time is 7-8h, the pressure is 0.4Pa, and the vacuum is 1x10 -4 ~6x10 -4 Pa.

[0035] Example 1

[0036] S1. Using Ti, Al, and Nb as synthetic raw materials, a Ti-45Al-8Nb (at.%) matrix with a size of 10×10×2 mm was obtained by vacuum non-consumable arc melting technology.

[0037] S2. The Ti-45Al-8Nb (at.%) matrix prepared in step S1 is polished successively with 200#, 400#, 800#, 1000#, and 1200# water-abrasive sandpaper, and then polished to a mirror surface with a polishing machine.

[0038] S3. The polished Ti-45Al-8Nb (at.%) substrate obtained in step S2 is placed in a 99.9% alcohol solution for ultrasonic cleaning to remove dirt. The ultrasonic frequency is 53 kHz. After cleaning for 10 minutes, the substrate is placed in an 80° C. oven for drying and then set aside.

[0039] S4. Weigh pure metal raw materials of Al, Co, Cr, Fe, and Ni and pure active raw materials of Dy and Hf according to the ratio; the atomic percentage content of Dy and Hf is 0.02at%; the atomic percentage content ratio of Al, Co, Cr, Fe, and Ni is 1:1:1:1. Before weighing the raw materials, the block, granular, and flaky raw materials are mechanically polished and ultrasonically cleaned in acetone or anhydrous ethanol to remove the oxide film and other sediment impurities; then the weighed raw materials Al, Co, Cr, Fe, Ni, and Al, Dy, Ni, Co, Fe, Cr, and Hf are placed in Nb foil in the order of melting point from low to high, and wrapped together and placed at the bottom of a copper crucible, and the copper crucible is placed in a vacuum non-consumable arc melting furnace for melting, and the vacuum is evacuated to 4-5×10 -3 Pa, and filled with high-purity argon to 1.0×105Pa for protection, the raw material is repeatedly smelted 5-6 times under argon protection to make the various elements in the material more evenly distributed and reduce the internal stress, and magnetic stirring is turned on during the smelting process. After smelting, a modified AlCoCrFeNi high-entropy alloy target is obtained, and then the modified AlCoCrFeNi high-entropy alloy target is cut by a wire cutting process, and the surface oil is ground off with water abrasive paper; the modified AlCoCrFeNi high-entropy alloy target with oil removed is placed in an alcohol solution for ultrasonic cleaning, the ultrasonic frequency is 50-60KHz, the cleaning time is 10min, and then it is placed in an 80°C oven for drying.

[0040] S5. Use 60# water-abrasive sandpaper to remove the surface oil stains of the high-entropy alloy target prepared in step S4, and then place it in a 99.9% alcohol solution for ultrasonic cleaning to remove dirt. Under the condition of ultrasonic frequency of 53KHz, after cleaning for 10 minutes, place it in an oven for drying and set aside for use.

[0041] S6. Preparation of high-entropy alloy thin films with uniform composition by magnetron sputtering

[0042] The Ti-45Al-8Nb (at.%) substrate dried in S3 was mounted on the fixture of the magnetron sputtering equipment, and the high entropy alloy target dried in S5 was placed on the RF target for sputtering. The magnetron sputtering process parameters were adjusted as follows: Ti-45Al-8Nb substrate temperature 80 °C, high entropy alloy target power 300 W, sputtering time 8 h, gas pressure 0.4 Pa, vacuum 1x10 -4 Pa.

[0043] The magnetron sputtering equipment used in this example is from Shenyang Scientific Instrument Co., Ltd., Chinese Academy of Sciences.

[0044] The magnetron sputtering equipment produced by Figure 1 Schematic diagram of magnetron sputtering. Figure 2 is a BSE cross-sectional view of the high entropy alloy film prepared in Example 1 of the present application and the content of each element at the points taken in the view; Figure 3 is the GiXRD pattern of the high entropy alloy film prepared in Example 1 of the present application; Figure 4 This is the oxidation weight gain curve of the high-entropy alloy film prepared in Example 1 of the present application compared with the TiAl alloy oxidized at 900°C for 100h, wherein HEF1 is a Dy and Hf modified AlCoCrFeNi high-entropy alloy film, HEF2 is an unmodified AlCoCrFeNi high-entropy alloy film, HEF3 is a Dy-modified AlCoCrFeNi high-entropy alloy film, and HEF4 is an Hf-modified AlCoCrFeNi high-entropy alloy film. It can be seen from the figure that compared with the TiAl alloy, the oxidation weight gain of the unmodified AlCoCrFeNi high-entropy alloy film oxidized at 900°C for 100h has been significantly reduced, and the oxidation weight gain of the Dy and Hf modified AlCoCrFeNi high-entropy alloy film is further reduced.

[0045] Example 2

[0046] S1. Using Ti, Al, and Nb as synthetic raw materials, a Ti-45Al-8Nb (at.%) matrix was obtained by vacuum non-consumable arc melting technology. The obtained Ti-45Al-8Nb (at.%) matrix was then polished using 200#, 400#, 800#, 1000#, and 1200# water-abrasive sandpaper in sequence, and then polished to a mirror finish using a polishing machine. The polished Ti-45Al-8Nb (at.%) matrix was then ultrasonically cleaned in an 85% alcohol solution at a frequency of 50 kHz for 10 minutes to remove dirt. The matrix was then dried in an 80°C oven for later use.

[0047] S2. Weigh pure metal raw materials of Al, Co, Cr, Fe, and Ni and pure active raw materials of Dy and Hf according to the ratio; the atomic percentage content of Dy and Hf is 0.01 at%; the atomic percentage content ratio of Al, Co, Cr, Fe, and Ni is 1:1:1:1. Before weighing the raw materials, the block, granular, and flaky raw materials are mechanically polished and ultrasonically cleaned in acetone or anhydrous ethanol to remove the oxide film and other sediment impurities; then, the weighed raw materials Al, Co, Cr, Fe, and Ni are placed in the order of melting point from low to high, Al, Dy, Ni, Co, Fe, Cr, and Hf, and wrapped together in Nb foil and placed at the bottom of a copper crucible. The copper crucible is placed in a vacuum non-consumable arc melting furnace for melting, and the vacuum is evacuated to 5×10 -3 Pa, and filled with high-purity argon to 1.0×105Pa for protection, the raw material is repeatedly smelted 5-6 times under argon protection to make the various elements in the material more evenly distributed and reduce the internal stress, and magnetic stirring is turned on during the smelting process. After smelting, a modified AlCoCrFeNi high-entropy alloy target is obtained, and then the modified AlCoCrFeNi high-entropy alloy target is cut by a wire cutting process, and the surface oil is removed by water abrasive paper; the modified AlCoCrFeNi high-entropy alloy target with oil removed is placed in an alcohol solution for ultrasonic cleaning, the ultrasonic frequency is 60KHz, and the cleaning time is 20min, and then it is placed in an 80℃ oven for drying, and then the obtained high-entropy alloy target is ground with 60# water abrasive paper to remove the surface oil, and then placed in an alcohol solution with a mass fraction of 99.9% for ultrasonic cleaning to remove dirt, under the condition of an ultrasonic frequency of 60KHz, after cleaning for 20min, it is placed in an oven for drying and standby use.

[0048] S3, the Ti-45Al-8Nb (at.%) substrate dried in S1 was mounted on the fixture of the magnetron sputtering equipment, and the high entropy alloy target dried in S2 was placed on the RF target for sputtering. The magnetron sputtering process parameters were adjusted as follows: Ti-45Al-8Nb substrate temperature 80°C, high entropy alloy target power 300 watts, sputtering time 7 h, gas pressure 0.4 Pa, vacuum 1x10 - 4 Pa.

[0049] Example 3

[0050] S1. Using Ti, Al, and Nb as synthetic raw materials, a Ti-45Al-8Nb (at.%) matrix was obtained by vacuum non-consumable arc melting technology. The obtained Ti-45Al-8Nb (at.%) matrix was then polished using 200#, 400#, 800#, 1000#, and 1200# water-abrasive sandpaper in sequence, and then polished to a mirror surface using a polishing machine. The polished Ti-45Al-8Nb (at.%) matrix was then ultrasonically cleaned in an 85% alcohol solution at an ultrasonic frequency of 60 kHz for 20 minutes to remove dirt. The matrix was then dried in an 80°C oven for later use.

[0051] S2. Weigh pure metal raw materials of Al, Co, Cr, Fe, and Ni and pure active raw materials of Dy and Hf according to the ratio; the atomic percentage content of Dy and Hf is 0.03 at%; the atomic percentage content ratio of Al, Co, Cr, Fe, and Ni is 1:1:1:1. Before weighing the raw materials, the block, granular, and flaky raw materials are mechanically polished and ultrasonically cleaned in acetone or anhydrous ethanol to remove the oxide film and other sediment impurities; then, the weighed raw materials Al, Co, Cr, Fe, and Ni are placed in the order of melting point from low to high, Al, Dy, Ni, Co, Fe, Cr, and Hf, and wrapped together in Nb foil and placed at the bottom of a copper crucible. The copper crucible is placed in a vacuum non-consumable arc melting furnace for melting, and the vacuum is evacuated to 5×10 -3 Pa, and filled with high-purity argon gas to 1.0×10 5 Pa is used for protection, and the raw materials are repeatedly smelted 5-6 times under argon protection to make the various elements in the material more evenly distributed and reduce the internal stress, and magnetic stirring is turned on during the smelting process. After smelting, a modified AlCoCrFeNi high-entropy alloy target is obtained, and then the modified AlCoCrFeNi high-entropy alloy target is cut by a wire cutting process, and the surface oil is ground off with water abrasive paper; the modified AlCoCrFeNi high-entropy alloy target with oil removed is placed in an alcohol solution for ultrasonic cleaning, the ultrasonic frequency is 50KHz, and the cleaning time is 15min, and then it is placed in an 80℃ oven for drying, and then the obtained high-entropy alloy target is ground off with 60# water abrasive paper to remove the surface oil, and then placed in an alcohol solution with a mass fraction of 90% for ultrasonic cleaning to remove dirt, under the condition of an ultrasonic frequency of 50KHz, after cleaning for 15min, it is placed in an oven for drying and standby use.

[0052] S3: The Ti-45Al-8Nb (at.%) substrate dried in S1 was mounted on the fixture of the magnetron sputtering equipment, and the high entropy alloy target dried in S2 was placed on the RF target for sputtering. The magnetron sputtering process parameters were adjusted as follows: Ti-45Al-8Nb substrate temperature 90°C, high entropy alloy target power 300W, sputtering time 7.5h, gas pressure 0.4Pa, vacuum 5x10 -4 Pa.

[0053] Example 4

[0054] S1. Using Ti, Al, and Nb as synthetic raw materials, a Ti-45Al-8Nb (at.%) matrix was obtained by vacuum non-consumable arc melting technology. The obtained Ti-45Al-8Nb (at.%) matrix was then polished using 200#, 400#, 800#, 1000#, and 1200# water-abrasive sandpaper in sequence, and then polished to a mirror surface using a polishing machine. The polished Ti-45Al-8Nb (at.%) matrix was then ultrasonically cleaned in an 85% alcohol solution at an ultrasonic frequency of 60 kHz for 20 minutes to remove dirt. The matrix was then dried in an 80°C oven for later use.

[0055] S2. Weigh pure metal raw materials of Al, Co, Cr, Fe, and Ni and pure active raw materials of Dy and Hf according to the ratio; the atomic percentage content of Dy is 0.03 at%; the atomic percentage content of Hf is 0.02 at%, and the atomic percentage ratio of Al, Co, Cr, Fe, and Ni is 1:1:1:1. Before weighing the raw materials, mechanically polish the block, granular, and flaky raw materials and ultrasonically clean them in acetone or anhydrous ethanol to remove oxide films and other sediment impurities; then, the weighed raw materials Al, Co, Cr, Fe, and Ni are placed in the order of melting point from low to high, Al, Dy, Ni, Co, Fe, Cr, and Hf, and wrapped together in Nb foil and placed at the bottom of a copper crucible. The copper crucible is placed in a vacuum non-consumable arc melting furnace for melting, and the vacuum is evacuated to 5×10 -3 Pa, and filled with high-purity argon gas to 1.0×10 5Pa is used for protection, and the raw materials are repeatedly smelted 5-6 times under argon protection to make the various elements in the material more evenly distributed and reduce the internal stress, and magnetic stirring is turned on during the smelting process. After smelting, a modified AlCoCrFeNi high-entropy alloy target is obtained, and then the modified AlCoCrFeNi high-entropy alloy target is cut by a wire cutting process, and the surface oil is ground off with water abrasive paper; the modified AlCoCrFeNi high-entropy alloy target with oil removed is placed in an alcohol solution for ultrasonic cleaning, the ultrasonic frequency is 50KHz, and the cleaning time is 15min, and then it is placed in an 80℃ oven for drying, and then the obtained high-entropy alloy target is ground off with 60# water abrasive paper to remove the surface oil, and then placed in an alcohol solution with a mass fraction of 90% for ultrasonic cleaning to remove dirt, under the condition of an ultrasonic frequency of 50KHz, after cleaning for 15min, it is placed in an oven for drying and standby use.

[0056] S3: The Ti-45Al-8Nb (at.%) substrate dried in S1 was mounted on the fixture of the magnetron sputtering equipment, and the high entropy alloy target dried in S2 was placed on the RF target for sputtering. The magnetron sputtering process parameters were adjusted as follows: Ti-45Al-8Nb substrate temperature 90°C, high entropy alloy target power 300W, sputtering time 7.5h, gas pressure 0.4Pa, vacuum 5x10 -4 Pa.

[0057] Comparative Example 1

[0058] In this comparative example, the content of pure Dy active material in atomic percentage is 0.02 at %, and the content of pure Hf active material in atomic percentage is 0 at %. The remaining steps and parameters are the same as those in Example 1.

[0059] S1. Using Ti, Al, and Nb as synthetic raw materials, a Ti-45Al-8Nb (at.%) matrix with a size of 10×10×2 mm was obtained by vacuum non-consumable arc melting technology.

[0060] S2. The Ti-45Al-8Nb (at.%) matrix prepared in step S1 is polished successively with 200#, 400#, 800#, 1000#, and 1200# water-abrasive sandpaper, and then polished to a mirror surface with a polishing machine.

[0061] S3. The polished Ti-45Al-8Nb (at.%) substrate obtained in step S2 is placed in a 99.9% alcohol solution for ultrasonic cleaning to remove dirt. The ultrasonic frequency is 53 kHz. After cleaning for 10 minutes, the substrate is placed in an 80° C. oven for drying and then set aside.

[0062] S4. Weigh pure metal raw materials of Al, Co, Cr, Fe, and Ni and pure active raw materials of Dy according to the ratio; the atomic percentage content of Dy is 0.02 at%; the atomic percentage content ratio of Al, Co, Cr, Fe, and Ni is 1:1:1:1. Before weighing the raw materials, the block, granular, and flaky raw materials are mechanically polished and ultrasonically cleaned in acetone or anhydrous ethanol to remove the oxide film and other sediment impurities; then, the weighed raw materials Al, Co, Cr, Fe, and Ni are placed in the order of melting point from low to high, Al, Dy, Ni, Co, Fe, and Cr are sequentially placed in Nb foil, wrapped together, and placed at the bottom of a copper crucible, and the copper crucible is placed in a vacuum non-consumable arc melting furnace for melting, and the vacuum is evacuated to 4 to 5×10 -3 Pa, and filled with high-purity argon to 1.0×105Pa for protection, the raw material is repeatedly smelted 5-6 times under argon protection to make the various elements in the material more evenly distributed and reduce the internal stress, and magnetic stirring is turned on during the smelting process. After smelting, a modified AlCoCrFeNi high-entropy alloy target is obtained, and then the modified AlCoCrFeNi high-entropy alloy target is cut by a wire cutting process, and the surface oil is ground off with water abrasive paper; the modified AlCoCrFeNi high-entropy alloy target with oil removed is placed in an alcohol solution for ultrasonic cleaning, the ultrasonic frequency is 50-60KHz, the cleaning time is 10min, and then it is placed in an 80°C oven for drying.

[0063] S5. Use 60# water-abrasive sandpaper to remove the surface oil stains of the high-entropy alloy target prepared in step S4, and then place it in a 99.9% alcohol solution for ultrasonic cleaning to remove dirt. Under the condition of ultrasonic frequency of 53KHz, after cleaning for 10 minutes, place it in an oven for drying and set aside for use.

[0064] S6. Preparation of high-entropy alloy thin films with uniform composition by magnetron sputtering

[0065] The Ti-45Al-8Nb (at.%) substrate dried in S3 was mounted on the fixture of the magnetron sputtering equipment, and the high entropy alloy target dried in S5 was placed on the RF target for sputtering. The magnetron sputtering process parameters were adjusted as follows: Ti-45Al-8Nb substrate temperature 80 °C, high entropy alloy target power 300 W, sputtering time 8 h, gas pressure 0.4 Pa, vacuum 1x10 -4 Pa.

[0066] Depend on Figure 4 It can be seen that the anti-oxidation performance of the modified example doped with Dy alone is slightly worse than that of the modified example co-doped with Dy and Hf.

[0067] Comparative Example 2

[0068] In this comparative example, the atomic percentage content of pure Dy active material is 0 at %, the atomic percentage content of pure Hf active material is 0.02 at %, and the remaining steps and parameters are the same as those in Example 1.

[0069] S1. Using Ti, Al, and Nb as synthetic raw materials, a Ti-45Al-8Nb (at.%) matrix with a size of 10×10×2 mm was obtained by vacuum non-consumable arc melting technology.

[0070] S2. The Ti-45Al-8Nb (at.%) matrix prepared in step S1 is polished successively with 200#, 400#, 800#, 1000#, and 1200# water-abrasive sandpaper, and then polished to a mirror surface with a polishing machine.

[0071] S3. The polished Ti-45Al-8Nb (at.%) substrate obtained in step S2 is placed in a 99.9% alcohol solution for ultrasonic cleaning to remove dirt. The ultrasonic frequency is 53 kHz. After cleaning for 10 minutes, the substrate is placed in an 80° C. oven for drying and then set aside.

[0072] S4. Weigh pure metal raw materials of Al, Co, Cr, Fe, Ni and pure active raw materials of Dy according to the ratio; the atomic percentage content of Dy is 0.02 at%; the atomic percentage content ratio of Al, Co, Cr, Fe, and Ni is 1:1:1:1. Before weighing the raw materials, the block, granular, and flaky raw materials are mechanically polished and ultrasonically cleaned in acetone or anhydrous ethanol to remove the oxide film and other sediment impurities; then, the weighed raw materials of Al, Co, Cr, Fe, and Ni are placed in the order of melting point from low to high, Al, Ni, Co, Fe, Cr, and Hf, and wrapped together in Nb foil and placed at the bottom of a copper crucible. The copper crucible is placed in a vacuum non-consumable arc melting furnace for melting, and the vacuum is evacuated to 4-5×10 -3 Pa, and filled with high-purity argon to 1.0×105Pa for protection, the raw material is repeatedly smelted 5-6 times under argon protection to make the various elements in the material more evenly distributed and reduce the internal stress, and magnetic stirring is turned on during the smelting process. After smelting, a modified AlCoCrFeNi high-entropy alloy target is obtained, and then the modified AlCoCrFeNi high-entropy alloy target is cut by a wire cutting process, and the surface oil is ground off with water abrasive paper; the modified AlCoCrFeNi high-entropy alloy target with oil removed is placed in an alcohol solution for ultrasonic cleaning, the ultrasonic frequency is 50-60KHz, the cleaning time is 10min, and then it is placed in an 80°C oven for drying.

[0073] S5. Use 60# water-abrasive sandpaper to remove the surface oil stains of the high-entropy alloy target prepared in step S4, and then place it in a 99.9% alcohol solution for ultrasonic cleaning to remove dirt. Under the condition of ultrasonic frequency of 53KHz, after cleaning for 10 minutes, place it in an oven for drying and set aside for use.

[0074] S6. Preparation of high-entropy alloy thin films with uniform composition by magnetron sputtering

[0075] The Ti-45Al-8Nb (at.%) substrate dried in S3 was mounted on the fixture of the magnetron sputtering equipment, and the high entropy alloy target dried in S5 was placed on the RF target for sputtering. The magnetron sputtering process parameters were adjusted as follows: Ti-45Al-8Nb substrate temperature 80 °C, high entropy alloy target power 300 W, sputtering time 8 h, gas pressure 0.4 Pa, vacuum 1x10 -4 Pa. By Figure 4 It can be seen that the oxidation resistance of the modified example doped with Hf alone is slightly worse than that of the modified example co-doped with Dy and Hf.

[0076] Comparative Example 3

[0077] In this comparative example, the atomic percentage content of pure Dy active material is 0 at %, the atomic percentage content of pure Hf active material is 0 at %, and the remaining steps and parameters are the same as those in Example 1.

[0078] S1. Using Ti, Al, and Nb as synthetic raw materials, a Ti-45Al-8Nb (at.%) matrix with a size of 10×10×2 mm was obtained by vacuum non-consumable arc melting technology.

[0079] S2. The Ti-45Al-8Nb (at.%) matrix prepared in step S1 is polished successively with 200#, 400#, 800#, 1000#, and 1200# water-abrasive sandpaper, and then polished to a mirror surface with a polishing machine.

[0080] S3. The polished Ti-45Al-8Nb (at.%) substrate obtained in step S2 is placed in a 99.9% alcohol solution for ultrasonic cleaning to remove dirt. The ultrasonic frequency is 53 kHz. After cleaning for 10 minutes, the substrate is placed in an 80° C. oven for drying and then set aside.

[0081] S4. Weigh pure metal raw materials of Al, Co, Cr, Fe, and Ni and pure active raw materials of Dy according to the ratio; the atomic percentage content of Dy is 0.02 at%; the atomic percentage content ratio of Al, Co, Cr, Fe, and Ni is 1:1:1:1. Before weighing the raw materials, the block, granular, and flaky raw materials are mechanically polished and ultrasonically cleaned in acetone or anhydrous ethanol to remove the oxide film and other sediment impurities; then, the weighed raw materials Al, Co, Cr, Fe, and Ni are placed in the order of melting point from low to high, Al, Ni, Co, Fe, and Cr, in Nb foil, wrapped together, and placed at the bottom of a copper crucible, and the copper crucible is placed in a vacuum non-consumable arc melting furnace for melting, and the vacuum is evacuated to 4 to 5×10 -3 Pa, and filled with high-purity argon to 1.0×105Pa for protection, the raw material is repeatedly smelted 5-6 times under argon protection to make the various elements in the material more evenly distributed and reduce the internal stress, and magnetic stirring is turned on during the smelting process. After smelting, a modified AlCoCrFeNi high-entropy alloy target is obtained, and then the modified AlCoCrFeNi high-entropy alloy target is cut by a wire cutting process, and the surface oil is ground off with water abrasive paper; the modified AlCoCrFeNi high-entropy alloy target with oil removed is placed in an alcohol solution for ultrasonic cleaning, the ultrasonic frequency is 50-60KHz, the cleaning time is 10min, and then it is placed in an 80°C oven for drying.

[0082] S5. Use 60# water-abrasive sandpaper to remove the surface oil stains of the high-entropy alloy target prepared in step S4, and then place it in a 99.9% alcohol solution for ultrasonic cleaning to remove dirt. Under the condition of ultrasonic frequency of 53KHz, after cleaning for 10 minutes, place it in an oven for drying and set aside for use.

[0083] S6. Preparation of high-entropy alloy thin films with uniform composition by magnetron sputtering

[0084] The Ti-45Al-8Nb (at.%) substrate dried in S3 was mounted on the fixture of the magnetron sputtering equipment, and the high entropy alloy target dried in S5 was placed on the RF target for sputtering. The magnetron sputtering process parameters were adjusted as follows: Ti-45Al-8Nb substrate temperature 80 °C, high entropy alloy target power 300 W, sputtering time 8 h, gas pressure 0.4 Pa, vacuum 1x10 -4 Pa.

[0085] Example 4

[0086] Oxidation performance is one of the most important properties of TiAl alloys. This application characterizes the oxidation performance of TiAl alloys with Dy and Hf modified AlCoCrFeNi high entropy alloy films and TiAl alloys with unmodified AlCoCrFeNi high entropy alloy films through high-temperature oxidation experiments. The specific steps are as follows:

[0087] Step 1: Place the sample in anhydrous ethanol, ultrasonically clean for 10 minutes, blow dry with cold air, measure the sample size and weigh the original weight.

[0088] Step 2: Place the 95% porcelain alumina crucible and porcelain boat into anhydrous ethanol, ultrasonically treat for 10 minutes, and blow dry for later use.

[0089] Step 3: Heat the high-temperature oxidation tube furnace to 900°C. Use an S-type platinum-rhodium thermocouple to calibrate the temperature of the tube furnace. Place one end of the thermocouple in the constant temperature zone of the tube furnace and connect the other end of the thermocouple to a digital potentiometer to measure the actual temperature inside the furnace tube and adjust the equipment to the accurate operating temperature.

[0090] Step 4: Place the cleaned 95% porcelain alumina crucible and porcelain boat in a tube furnace and dry them for 30 minutes to remove ethanol and other impurities.

[0091] Step 5: Place the sample in an alumina crucible and use nickel-chromium wire to mark the crucible and the crucible lid with numbers. Place them in a porcelain boat and push the porcelain boat to the constant temperature zone of the tube furnace.

[0092] Step 6: After oxidation for 1, 5, 10, 24, 48, 72, and 100 hours, take out the sample, cool it to room temperature using a fan, weigh it, and store it in a sample box.

[0093] Therefore, the present application provides a method for depositing Dy and Hf modified AlCoCrFeNi high entropy alloy films to improve the oxidation resistance of TiAl alloys, and the obtained modified AlCoCrFeNi high entropy alloy films improve the oxidation resistance of TiAl alloys.

[0094] In this specification, references to terms such as "an experimental example," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that experimental example or example are included in at least one experimental example or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same experimental example or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more experimental examples or examples.

[0095] Finally, it should be noted that the above experimental examples are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred experimental examples, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for depositing Dy and Hf modified AlCoCrFeNi high entropy alloy thin films to improve the oxidation resistance of TiAl alloys, characterized in that: The following steps are involved: S1. Using Ti, Al and Nb as synthetic raw materials, a Ti-45Al-8Nb matrix was prepared using vacuum non-consumable arc melting technology; S2. Weigh pure metal raw materials Al, Co, Cr, Fe, Ni and pure active raw materials Dy and Hf, and prepare a modified AlCoCrFeNi high entropy alloy target by using vacuum non-consumable arc melting technology; In the modified AlCoCrFeNi high entropy alloy target, the doping amount of Dy and Hf is 0.01-0.03%at; In the modified AlCoCrFeNi high entropy alloy target, the atomic ratio of Al, Co, Cr, Fe, and Ni is 1:1:1:1:1; S3, mounting the Ti-45Al-8Nb substrate in step S1 on a fixture of a magnetron sputtering device, placing the modified AlCoCrFeNi high entropy alloy target in step S2 on a radio frequency target, and using magnetron sputtering technology to obtain a TiAl alloy covered with a modified AlCoCrFeNi high entropy alloy film; In step S3, the magnetron sputtering parameters are as follows: the temperature of the Ti-45Al-8Nb substrate is 80-100°C, the power of the AlCoCrFeNi high entropy alloy target is 300W, the sputtering time is 7-8h, the pressure is 0.4Pa, and the vacuum degree is 1x10 -4 ~6x10 -4 Pa.

2. The method for improving the oxidation resistance of TiAl alloy by depositing Dy and Hf modified AlCoCrFeNi high entropy alloy thin films according to claim 1, characterized in that: Step S1 also includes the following steps: 1) The prepared Ti-45Al-8Nb matrix was cut into samples using a wire cutting process, and the samples were polished with water-abrasive paper and then polished to a mirror surface using a polishing machine; 2) The Ti-45Al-8Nb substrate polished in step 1) is placed in an alcohol solution for ultrasonic cleaning at an ultrasonic frequency of 50-60 kHz for 10-20 minutes, and then dried in an 80° C. oven.

3. The method for improving the oxidation resistance of TiAl alloy by depositing Dy and Hf modified AlCoCrFeNi high entropy alloy thin films according to claim 1, characterized in that: Step S2 also includes the following steps: (1) The modified AlCoCrFeNi high entropy alloy target was cut by wire cutting and the surface oil was removed by sandpaper; (2) The modified AlCoCrFeNi high entropy alloy target treated in step (1) is placed in an alcohol solution for ultrasonic cleaning at an ultrasonic frequency of 50-60 kHz for 10-20 min, and then placed in an oven at 80°C for drying.

4. The method for improving the oxidation resistance of TiAl alloy by depositing Dy and Hf modified AlCoCrFeNi high entropy alloy thin films according to claim 2, characterized in that: In the step 1), the sample is polished with 200#, 400#, 800#, 1000#, and 1200# water-abrasive sandpaper in sequence.

5. The method for improving the oxidation resistance of TiAl alloy by depositing Dy and Hf modified AlCoCrFeNi high entropy alloy thin films according to claim 2 or 3, characterized in that: The mass fraction of the alcohol solution is 85-99.9%.

6. The method for improving the oxidation resistance of TiAl alloy by depositing Dy and Hf modified AlCoCrFeNi high entropy alloy thin films according to claim 1, characterized in that: Before weighing pure metal raw materials Al, Co, Cr, Fe, Ni and pure active raw materials Dy and Hf, the block, granular and flaky pure metal raw materials Al, Co, Cr, Fe, Ni and pure active raw materials Dy and Hf are mechanically polished and ultrasonically cleaned in acetone or anhydrous ethanol to remove oxide films and sediment impurities. They are then placed in Nb foil in order of melting point from low to high, wrapped together and placed at the bottom of a copper crucible for smelting.

7. The method for improving the oxidation resistance of TiAl alloy by depositing Dy and Hf modified AlCoCrFeNi high entropy alloy thin films according to claim 6, characterized in that: During melting, vacuum is drawn to 4~5×10 -3 Pa, and filled with high-purity argon gas to 1.0×10 5 Pa is used for protection, and the raw materials are repeatedly melted 5-6 times under argon protection.

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