Sub-micron cell structure wear-resistant and oxidation-resistant high-entropy alloy coating, and preparation method and application thereof

Abstract

The application provides a sub-micron cell structure wear-resistant and oxidation-resistant high-entropy alloy coating and a preparation method and application thereof, and belongs to the technical field of metal material surface treatment.The sub-micron cell structure wear-resistant and oxidation-resistant high-entropy alloy coating provided by the application comprises the following components in terms of mass fraction: Co 32-38%, Cr 22-28%, Ni 22-28%, W 12-18% and Mn 1-3%.The coating can be applied to a Ni-based high-temperature alloy and a Co-based high-temperature alloy substrate by using a small-spot laser cladding technology, has a special solidification structure of a sub-micron cell structure, has excellent wear resistance and high-temperature oxidation resistance, can be used for surface strengthening of key hot end parts of an aero-engine, and has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of surface treatment technology for metallic materials, and in particular to a submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating, its preparation method, and its application. Background Technology

[0002] Under the high-temperature and high-pressure operating conditions of aerospace engines, the working environment of many hot-end components is extremely harsh. Improving the high-temperature mechanical properties, oxidation resistance, and wear resistance of these components can effectively enhance engine performance and reduce production and maintenance costs. Currently, a relatively economical method for strengthening components is through surface strengthening technology to improve the wear resistance and oxidation resistance of key components. High-entropy alloys exhibit superior hardness, corrosion resistance, wear resistance, and high-temperature oxidation resistance compared to many traditional alloys. Therefore, developing wear-resistant and oxidation-resistant high-entropy alloy coatings for aerospace engines has broad application prospects.

[0003] However, current research on high-entropy alloy coatings mostly begins with FCC phase high-entropy alloy systems primarily composed of transition metals Co, Ni, Cr, and Fe, mainly systems such as FeCoCrMnNi, FeCoCrNi, FeCoMnNi, and CoCrMnNi. With the development of high-entropy alloys, transition elements with large atomic radii, such as Ti, Al, and V, as well as refractory elements like Ta, Zr, Hf, Nb, and W, have been gradually added. The phase structure has also evolved with the addition of different elements, from the initial FCC single-phase solid solution to BCC single-phase, HCP single-phase, two-phase, and complex matrix structures containing TRIP, and complex precipitate phase characteristics such as TCP, L1, and B2 have gradually emerged.

[0004] Under current technological conditions, research on wear-resistant and oxidation-resistant high-entropy alloy coatings for aerospace engines still faces several challenges: First, excellent bonding performance with Ni-based and Co-based superalloys is required. Second, to ensure stability during thermal cycling in applications involving hot-end components of aerospace engines, it is necessary to prevent matrix phase transformations caused by temperature changes, which could lead to coating detachment due to mismatched coefficients of thermal expansion. Ideally, such coating materials should have a stable FCC phase structure. Third, because the FCC phase inherently possesses numerous slip systems, it is more difficult to improve its strength and hardness through solid solution strengthening compared to BCC solid solutions. Therefore, for FCC phases, it is usually necessary to add precipitated phases to improve the material's wear resistance. However, the addition of precipitated phases reduces the material's oxidation resistance; therefore, for FCC phase metallic materials, wear resistance and oxidation resistance are typically mutually exclusive. Summary of the Invention

[0005] The purpose of this invention is to provide a submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating, its preparation method and application. This coating can be applied to Ni-based and Co-based high-temperature alloy substrates. Its microstructure has a submicron cellular structure, and it has excellent wear resistance and high-temperature oxidation resistance.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating. The raw material includes a CoCrNiW-Mn high-entropy alloy, which, by mass fraction, comprises the following components: Co 32-38%, Cr 22-28%, Ni 22-28%, W 12-18%, and Mn 1-3%.

[0008] The method for preparing the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating includes the following steps:

[0009] After preheating, the CoCrNiW-Mn high-entropy alloy is laser-clad onto the substrate surface and then annealed to obtain a submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating.

[0010] This invention also provides a method for preparing a submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating, comprising the following steps:

[0011] After preheating, the CoCrNiW-Mn high-entropy alloy is laser-clad onto the substrate surface and then annealed to obtain a submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating.

[0012] Preferably, the CoCrNiW-Mn high-entropy alloy needs to be prepared into CoCrNiW-Mn high-entropy alloy powder through gas atomization powder preparation before use.

[0013] Preferably, the particle size of the CoCrNiW-Mn high-entropy alloy powder is 10–80 μm.

[0014] Preferably, the preheating temperature is 80–300°C.

[0015] Preferably, the conditions for laser cladding include: a laser beam spot size of 100–400 μm, a scanning speed of 0.5–5 m / s, and a power of 50–500 W.

[0016] Preferably, during the laser cladding process, the CoCrNiW-Mn high-entropy alloy is deposited on the substrate surface with a thickness of 40–60 μm.

[0017] Preferably, the preheating and laser cladding processes are repeated multiple times until the required coating thickness is achieved.

[0018] Preferably, the annealing conditions include: heating to 450-500°C at a heating rate of 5-15°C / min, holding at that temperature for 8-10 hours, and then cooling.

[0019] This invention provides the application of the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating described in the above technical solution or the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating prepared by the preparation method described in the above technical solution in the field of aerospace hot-end components.

[0020] The beneficial effects of this invention are as follows:

[0021] Based on the specific composition of the CoCrNiW-Mn high-entropy alloy raw material and the ultrafast cooling rate and large temperature gradient characteristics during the small-spot (100μm) laser cladding process, the coating material achieves unique solidification behavior, resulting in a submicron-level (300-700nm) cellular microstructure. This microstructure effectively enhances the coating's strength, hardness, and toughness, exhibiting excellent wear resistance and high-temperature oxidation resistance. The coating matrix is ​​a stable FCC phase structure, demonstrating excellent metallurgical bonding properties with Ni-based and Co-based superalloys commonly used in aerospace engines. The coating is resistant to cracking, delamination, and separation from the substrate.

[0022] This high-entropy alloy coating has a high melting point, and its matrix structure is stable at high temperatures and exhibits oxidation resistance. The high-melting-point element composition design ensures that the coating matrix has a high melting point and stable oxidation thermodynamics. In addition, under the specific CoCrNiW-Mn composition design, a dense and stable oxide film can be generated at high temperatures, protecting the matrix from further oxidation. The oxidation products at high temperatures are an outer layer of MnCr2O4 spinel and a Cr2O3 oxide film. The Cr2O3 oxide film provides passivation protection at high temperatures, while the outer MnCr2O4 spinel reduces the oxygen partial pressure, thereby preventing the Cr2O3 oxide film from further oxidizing to CrO3 gas at high temperatures. This protects the integrity of the passivation film, enabling the coating to maintain excellent oxidation resistance even at high temperatures of 1100℃. Attached Figure Description

[0023] Figure 1 This is a scanning electron micrograph of the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating obtained in Example 1 of the present invention. Detailed Implementation

[0024] This invention provides a submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating. The raw material includes a CoCrNiW-Mn high-entropy alloy, which, by mass fraction, comprises the following components: Co 32-38%, Cr 22-28%, Ni 22-28%, W 12-18%, and Mn 1-3%.

[0025] The method for preparing the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating includes the following steps:

[0026] After preheating, the CoCrNiW-Mn high-entropy alloy is laser-clad onto the substrate surface and then annealed to obtain a submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating.

[0027] Based on mass fraction, the CoCrNiW-Mn high-entropy alloy provided by the present invention comprises 32-38% Co, preferably 33-36%, and more preferably 34-35%.

[0028] The CoCrNiW-Mn high-entropy alloy comprises 22-28% Cr by mass fraction, preferably 23-27%, and more preferably 24-26%.

[0029] The CoCrNiW-Mn high-entropy alloy comprises 22-28% Ni by mass fraction, preferably 23-27%, and more preferably 24-26%.

[0030] The CoCrNiW-Mn high-entropy alloy comprises 12-18% W by mass fraction, preferably 13-17%, and more preferably 14-16%.

[0031] The CoCrNiW-Mn high-entropy alloy comprises 1-3% Mn by mass fraction, preferably 1-2%, and more preferably 1-1.5%.

[0032] The present invention does not impose any special limitations on the preparation method of the CoCrNiW-Mn high-entropy alloy; the melting can be carried out according to a process well known in the art.

[0033] This invention also provides a method for preparing a submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating, comprising the following steps:

[0034] After preheating, the CoCrNiW-Mn high-entropy alloy is laser-clad onto the substrate surface and then annealed to obtain a submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating.

[0035] In this invention, the CoCrNiW-Mn high-entropy alloy needs to be processed by gas atomization to obtain CoCrNiW-Mn high-entropy alloy powder before use. The high-entropy alloy powder with a particle size of 10-80 μm is collected by sieving, preferably with a particle size of 20-60 μm.

[0036] The preferred method for gas atomization powder preparation in this invention is as follows: after melting the raw material of CoCrNiW-Mn high-entropy alloy into a melt, the melt is broken into fine droplets by high-pressure inert gas, and after solidification and cooling, CoCrNiW-Mn high-entropy alloy powder is formed.

[0037] The present invention preferably uses a CNC grinding machine to treat the surface of the substrate, clean the oxides and rust on the surface of the substrate, and make the surface of the substrate smooth and bright; then the substrate is fixed on the worktable using a clamping device, and the required thickness of CoCrNiW-Mn high entropy alloy powder is evenly spread on the surface of the substrate, and then the CoCrNiW-Mn high entropy alloy powder is rolled and compacted with a flat roller and preheated.

[0038] In this invention, the preheating temperature is 80–300°C, preferably 100–200°C, and more preferably 140–160°C.

[0039] In this invention, the substrate is preferably the part to be processed. This invention does not have any special limitation on the part to be processed. Any part to be processed that requires coating in the art is acceptable. In the embodiments of this invention, it is specifically an Inconel 718 nickel-based high-temperature alloy substrate.

[0040] In this invention, a laser device is controlled by a robotic arm or a laser galvanometer device to perform laser cladding on freshly laid CoCrNiW-Mn high-entropy alloy powder. The laser cladding conditions include: a laser beam spot size of 100–400 μm, a scanning speed of 0.5–5 m / s, and a power of 50–500 W. Argon gas protection is used during the laser cladding process.

[0041] The conditions for laser cladding include: the laser beam spot size is 100-400 μm, preferably 100-300 μm, and more preferably 100-150 μm.

[0042] The conditions for laser cladding include: the scanning speed of the laser beam is 0.5 to 5 m / s, preferably 0.5 to 3 m / s, and more preferably 0.5 to 1.5 m / s.

[0043] The conditions for laser cladding include: the power of the laser beam is 50-500W, preferably 100-400W, and more preferably 250-350W.

[0044] In this invention, during the laser cladding process, the CoCrNiW-Mn high-entropy alloy is deposited on the surface of the substrate with a thickness of 40-60 μm, preferably 40-50 μm, and more preferably 40-45 μm.

[0045] In this invention, preheating and laser cladding are repeated multiple times, preferably 10 to 50 times, until the required thickness of the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating is achieved.

[0046] In this invention, the substrate with the coating completed is placed in a muffle furnace for annealing. The annealing conditions include: heating to 450-500°C at a heating rate of 5-15°C per minute, holding at that temperature for 8-10 hours, and then cooling in the furnace.

[0047] The annealing conditions preferably include a heating rate of 5–15°C per minute, more preferably 5–10°C, and even more preferably 5–7°C.

[0048] The annealing conditions preferably include: heating to 450–500°C, more preferably 450–480°C, and even more preferably 450–460°C.

[0049] The annealing conditions preferably include: holding at heat for 8 to 10 hours and then cooling in the furnace, preferably 9 to 10 hours, and more preferably 9.5 to 10 hours.

[0050] In this invention, the substrate after annealing is preferably polished to remove the processing slag.

[0051] This invention provides the application of the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating described in the above-described technical solutions, or the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating prepared by the preparation method described in the above-described technical solutions, in the field of aerospace hot-end components. This invention does not specifically limit the method of application; any method well-known in the art can be used.

[0052] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0053] Example 1

[0054] This embodiment provides a method for preparing a submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating, the specific process of which is as follows:

[0055] 1. Using CoCrNiW-Mn high-entropy alloy powder as raw material, the composition by weight percentage is as follows: Cr: 25%, Ni: 25%, W: 15%, Mn: 1%, with the remainder being Co. The CoCrNiW-Mn high-entropy master alloy is first smelted into a melt in a vacuum induction melting furnace, and then argon gas is introduced through a gas atomization device to prepare CoCrNiW-Mn high-entropy alloy powder. Powder with a particle size of 10-80μm is collected by sieving and reserved for later use.

[0056] 2. Use a CNC grinding machine to treat the surface of the substrate to be processed. The substrate to be processed is an Inconel 718 nickel-based high-temperature alloy substrate. Clean the oxides and rust on the surface of the substrate to make the surface of the substrate smooth and free of stains.

[0057] 3. The clamping device fixes the substrate on the worktable, and spreads a 40μm thick CoCrNiW-Mn high-entropy alloy powder evenly on the surface of the substrate. Then, the metal powder is rolled and compacted by a flat roller and preheated at a temperature of 150℃.

[0058] 4. The laser beam is controlled by a laser galvanometer device to perform laser cladding on the freshly laid metal powder layer at a speed of 1 m / s. The spot size is 100 μm and the laser power is 300 W. Argon gas protection is used during the laser cladding process.

[0059] 5. After laser cladding, repeat steps 3 and 4 20 times to complete the coating preparation;

[0060] 6. Place the coated parts into a muffle furnace for stress-relief annealing. Heat the parts to 450°C at a rate of 5°C per minute, hold for 10 hours, cool with the furnace, and then remove them.

[0061] Example 2

[0062] This embodiment provides a method for preparing a submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating, the specific process of which is as follows:

[0063] 1. Using CoCrNiW-Mn high-entropy alloy powder as raw material, the composition by weight percentage is as follows: Cr: 27%, Ni: 24%, W: 17%, Mn: 2%, with the remainder being Co. The CoCrNiW-Mn high-entropy master alloy is first smelted into a melt in a vacuum induction melting furnace, and then argon gas is introduced through a gas atomization device to prepare CoCrNiW-Mn high-entropy alloy powder. Powder with a particle size of 20-60μm is collected by sieving and reserved for later use.

[0064] 2. Use a CNC grinding machine to treat the surface of the substrate to be processed. The substrate to be processed is an Inconel 718 nickel-based high-temperature alloy substrate. Clean the oxides and rust on the surface of the substrate to make the surface of the substrate smooth and free of stains.

[0065] 3. The clamping device fixes the substrate on the worktable, and spreads a 40μm thick CoCrNiW-Mn high-entropy alloy powder evenly on the surface of the substrate. Then, the metal powder is rolled and compacted by a flat roller and preheated at a temperature of 160℃.

[0066] 4. The laser beam is controlled by a laser galvanometer device to perform laser cladding on the freshly laid metal powder layer at a speed of 2m / s. The spot size is 100μm and the laser power is 300W. Argon gas protection is used during the laser cladding process.

[0067] 5. After laser cladding, repeat steps 3 and 4 30 times to complete the coating preparation;

[0068] 6. Place the coated parts into a muffle furnace for stress-relief annealing. Heat the parts to 460°C at a rate of 7°C per minute, hold for 10 hours, cool with the furnace, and then remove them.

[0069] Characterization and performance testing

[0070] Figure 1 This is a scanning electron micrograph of the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating obtained in Example 1 of the present invention. Through observation... Figure 1 As can be seen, the coating prepared in Example 1 of the present invention can exhibit fine cellular structures of about 300 nm.

[0071] The Inconel 718 nickel-based superalloy matrix used in Examples 1-2 of this invention was subjected to tribological and oxidation resistance tests according to GB / T38430-2019 "Corrosion of Metals and Alloys - Isothermal Exposure Oxidation Test Method for Metallic Materials under High-Temperature Corrosion Conditions". The tribological and oxidation resistance tests employed reciprocating linear friction under the following conditions: room temperature, dry friction, SiC ceramic balls as the grinding pair, and a wear time of 20 minutes. The oxidation resistance tests used static oxidation samples placed at 1100℃ for 200 hours. The test results are shown in Table 1 below.

[0072] Table 1. Tests for Abrasion Resistance and Oxidation Resistance

[0073]

[0074]

[0075] The results in Table 1 show that the coating of Example 1 improved the friction and wear performance by nearly 6 times and the oxidation resistance by nearly 18 times compared with the uncoated Inconel 718 nickel-based superalloy substrate. The coating of Example 2 improved the friction and wear performance by nearly 6 times and the oxidation resistance by nearly 16 times compared with the uncoated Inconel 718 nickel-based superalloy substrate.

[0076] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating, characterized in that, The raw material includes a CoCrNiW-Mn high-entropy alloy, which, by mass fraction, is composed of the following components: Co 32-38%, Cr 22-28%, Ni 22-28%, W 12-18%, and Mn 1-3%. The method for preparing the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating includes the following steps: After preheating, the CoCrNiW-Mn high-entropy alloy is laser-clad onto the substrate surface and then annealed to obtain a submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating.

2. The method for preparing the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating according to claim 1, characterized in that, Includes the following steps: After preheating, the CoCrNiW-Mn high-entropy alloy is laser-clad onto the substrate surface and then annealed to obtain a submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating.

3. The method for preparing the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating according to claim 2, characterized in that, The CoCrNiW-Mn high-entropy alloy needs to be processed by gas atomization to obtain CoCrNiW-Mn high-entropy alloy powder before use.

4. The method for preparing the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating according to claim 3, characterized in that, The particle size of the CoCrNiW-Mn high-entropy alloy powder is 10–80 μm.

5. The method for preparing the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating according to claim 2, characterized in that, The preheating temperature is 80–300°C.

6. The method for preparing the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating according to claim 2, characterized in that, The conditions for laser cladding include: a laser beam spot size of 100–400 μm, a scanning speed of 0.5–5 m / s, and a power of 50–500 W.

7. The method for preparing the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating according to claim 2, characterized in that, During the laser cladding process, the CoCrNiW-Mn high-entropy alloy is deposited on the substrate surface with a thickness of 40–60 μm.

8. The method for preparing the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating according to claim 2, characterized in that, Repeat the preheating and laser cladding process multiple times until the required coating thickness is achieved.

9. The method for preparing the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating according to claim 2, characterized in that, The annealing conditions include: heating to 450-500°C at a heating rate of 5-15°C / min, holding at that temperature for 8-10 hours, and then cooling.

10. The application of the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating as described in claim 1 or the submicron cellular structure wear-resistant and oxidation-resistant high-entropy alloy coating prepared by the preparation method described in any one of claims 2 to 9 in the field of aerospace hot-end components.

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