A high-entropy alloy composite coating material and a preparation method thereof

Abstract

The application discloses a high-entropy alloy composite coating material and a preparation method thereof. The method comprises the following steps: weighing each powder according to the proportion of the high-entropy alloy composite coating material, and performing high-energy ball milling under the protection of inert gas to obtain mixed powder; using a laser cladding process to prepare a high-entropy alloy coating for the obtained mixed powder; and performing heat treatment on the prepared high-entropy alloy coating, wherein the heat treatment temperature is 800-1300 DEG C, the heat treatment time is 1.0-1.2 h, and the high-entropy alloy composite coating material is obtained after water quenching to room temperature after the heat treatment is completed. The eutectic high-entropy alloy coating is prepared by the method of the laser cladding process, the coating microstructure is changed by heat treatment and the addition of ceramic particles, the hardness, wear resistance and corrosion resistance of the coating can be improved while the FCC+BCC dual-phase eutectic microstructure in the coating is maintained, the process can be adjusted according to application requirements to obtain high-entropy alloy coatings with different performances, and the high-entropy alloy coatings are convenient for industrial application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high-entropy alloy materials, and particularly relates to a high-entropy alloy composite coating material and a preparation method thereof. BACKGROUND

[0002] High-entropy alloys (HEAs) are a new type of alloy composed of five or more (near) equal atomic ratio elements. Due to its special multi-principal element design concept, it has excellent mechanical properties, thermal stability, corrosion resistance and oxidation resistance, etc. AlCoCrFeNi 2.1 High-entropy alloys are of great concern due to their high strength and toughness balance and excellent comprehensive performance at high temperatures due to their FCC+BCC dual-phase structure. However, in the face of harsh working environments such as high temperature and high wear, the wear resistance and hardness of the alloy still have room for further improvement. SUMMARY

[0003] In order to solve the problems in the prior art, the present application aims to provide a high-entropy alloy composite coating material and a preparation method thereof.

[0004] The alloy releases internal thermal stress after heat treatment, thereby reducing internal defects of the alloy. When the phase in the alloy changes from a face-centered cubic solid solution phase to a body-centered cubic solid solution phase, the plasticity of the alloy decreases and the hardness increases. Therefore, heat treatment is often used as a post-treatment method to change the phase structure of the alloy and optimize the performance of the alloy. TiC is a hard ceramic particle with high hardness, high melting point and excellent wear resistance. Introducing TiC particles into the high-entropy alloy matrix can not only significantly improve the hardness and wear resistance of the alloy, but also improve its high-temperature creep resistance and oxidation resistance. The high-entropy alloy composite coating material provided by the present application is prepared by a heat treatment annealing process and the introduction of TiC particles into the AlCoCrFeNi 2.1 The high-entropy alloy composite has better wear resistance and mechanical properties, and can maintain excellent performance in extreme working environments.

[0005] To achieve the above-mentioned purposes, the specific technical solutions of the present application are as follows:

[0006] The present application provides a preparation method of a high-entropy alloy composite coating material, characterized in that it comprises the following steps:

[0007] (1) Weigh each powder according to the following high-entropy alloy composite coating material ratio, and perform high-energy ball milling under inert gas protection to obtain a mixed powder;

[0008] The high-entropy alloy composite coating material comprises, by mass percentage:

[0009] Al 4.56-5.96wt%

[0010] Co 10.01-13.01wt%

[0011] Cr 8.88-11.48wt%

[0012] Fe 9.53-12.88wt%

[0013] Ni 47.00-57.22wt%

[0014] TiC 0-20wt%

[0015] (2) For the mixed powder obtained in step (1), a high-entropy alloy coating is prepared by using a laser cladding process;

[0016] (3) The high-entropy alloy coating prepared in step (2) is subjected to heat treatment, the temperature of the heat treatment is 800-1300℃, the time is 1.0h, and after the heat treatment is completed, water quenching is performed to room temperature to obtain the high-entropy alloy composite coating material.

[0017] Further, the purity of Al, Co, Cr, Fe, Ni and TiC is all ≥ 99.9%.

[0018] Further, the rotation speed of the high-energy ball milling is 200-500r / min, the time of the high-energy ball milling is 4-8h, and the ball-to-material weight ratio is 1:5-1:10, so as to ensure that the powder is mixed sufficiently and the TiC particles are uniformly distributed in the metal powder.

[0019] Further, the laser power of the laser cladding process is 1200-2300w, the scanning speed is 400-1000mm / min, the powder feeding speed is 10-20g / min, the laser energy deposition method adopts single-layer multi-pass path, the spot diameter is 3-5mm, and the overlap rate is 50%.

[0020] Further, the mass percentage of TiC is 1-20wt%.

[0021] Further, the mass percentage of TiC is 1-5wt%.

[0022] Further, the temperature of the heat treatment is 800-1200℃.

[0023] Further, the temperature of the heat treatment is 800-1100℃.

[0024] Further, the mass percentage of TiC is 1-5wt%, and the temperature of the heat treatment is 1100℃.

[0025] Furthermore, in the laser cladding process, Q235 low-carbon steel is selected as the substrate. The oxide layer on the surface of the substrate is removed using an angle grinder, followed by polishing. Oil stains and impurities are removed with alcohol, and the substrate is dried. The uniformly mixed powder is placed in a laser generator, with high-purity argon as a protective gas, and the powder is melted using laser energy deposition to ensure the uniformity of the alloy coating.

[0026] The present invention also provides a high-entropy alloy composite coating material prepared by the preparation method described above.

[0027] The beneficial effects of this invention are as follows:

[0028] The AlCoCrFeNi of the present invention 2.1 High-entropy alloy composite coatings with TiC exhibit advantages such as high hardness, high wear resistance, high corrosion resistance, and high-temperature stability due to heat treatment and the reinforcing effect of TiC particles. The microstructure of the high-entropy alloy coating, prepared via laser cladding, can be altered through heat treatment. The FCC and BCC phase transformations achieve a balance between high strength and ductility. Adding TiC particles refines the coating's grain structure, improving its mechanical properties. The process can be adjusted to obtain high-entropy alloy composite coatings with different properties according to application requirements, facilitating industrial-scale application. Specifically:

[0029] High hardness: attributed to the release of residual stress and changes in the amount of FCC and BCC phases. Heat treatment makes Ni... 2.1 -EHEA microhardness is increased compared to the deposited state. Due to the addition of a certain amount of TiC particles, the solid solution strengthening mechanism caused by Ti and the second-phase strengthening mechanism caused by TiC particles significantly improve the hardness of the material and extend its service life.

[0030] High wear resistance: When the surface matrix wears, the dispersed TiC particles in the matrix are exposed, preventing further wear. On the other hand, the strengthening effect of the TiC second phase prevents large deformation of the matrix, thus reducing spalling. With increasing TiC content, deformation and grooves at the wear interface are significantly reduced, the interface becomes smoother, and debris is greatly reduced, indirectly demonstrating improved wear resistance.

[0031] High corrosion resistance: As the heat treatment temperature increases, the stability of the passivation film on the alloy surface decreases, the ion diffusion rate and electrochemical activity increase, and pitting corrosion intensifies. AlCoCrFeNi 2.1 EHEA is passivated in NaCl solution, but Cl - This disrupts the integrity of the passivation film, hinders passivation self-healing, and thus creates conditions for pitting corrosion. (The last sentence appears to be incomplete and possibly refers to a specific chemical process involving AlCoCrFeNi.) 2.1 The resulting film is a corrosion product film rather than a passivation film, making pitting corrosion very difficult to occur.

[0032] High-temperature stability: The composite material maintains good structural stability in high-temperature environments, making it suitable for high-temperature applications. Attached Figure Description

[0033] Figure 1 Example 1Ni 2.1 - SEM microstructure and EBSD phase distribution of EHEA at different heat treatment temperatures; (a,b) Untreated; (c,d) Heat treated at 1100℃; (e,f) Heat treated at 1200℃; (g,h) Heat treated at 1300℃.

[0034] Figure 2 AlCoCrFeNi under different heat treatment states in Example 1 2.1 Deposited layer hardness and room temperature tribological properties.

[0035] Figure 3 AlCoCrFeNi under different heat treatment states in Example 1 2.1 Deposited layer hardness and room temperature tribological properties.

[0036] Figure 4 Example 2: AlCoCrFeNi 2.1 -TiC x SEM-EDS microstructures of (x = 0, 1, 5, 10, 20 wt%); T1; (b) T5; (c) T10; (d) T20.

[0037] Figure 5 Example 2: AlCoCrFeNi 2.1 -TiC x SEM-EDS microhardness (x = 0, 1, 5, 10, 20 wt%); T1; (b) T5; (c) T10; (d) T20.

[0038] Figure 6 EBSD images of a composite coating with 1-5 wt% TiC added and heat-treated at 1100 °C.

[0039] Figure 7 Examples 8, 9, and Comparative Example 3AlCoCrFeNi 2.1 Microhardness of EHEA coating. Detailed Implementation

[0040] The technical solutions described below in conjunction with the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the 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.

[0041] In one specific embodiment, the present invention provides a method for preparing a high-entropy alloy composite coating material, and a heat-treated AlCoCrFeNi 2.1 The high-entropy alloy coating preparation process includes the following steps:

[0042] (1) Raw material preparation:

[0043] a. Select high-purity (≥99.9%) elemental powders of Al (5.96wt%), Co (13.01wt%), Cr (11.48wt%), Fe (12.33wt%), and Ni (57.22wt%).

[0044] b. Weigh out the powders of each element according to the above proportions.

[0045] (2) Laser cladding process:

[0046] c. The substrate is made of Q235 low-carbon steel. The oxide layer on the surface of the substrate is removed using an angle grinder, and then it is polished. Oil stains and impurities are removed with alcohol, and the substrate is dried.

[0047] d. Mix the metal element powders prepared in step b, and perform high-energy ball milling under inert gas protection. The ball milling time should be controlled at 4-8 hours to ensure thorough mixing.

[0048] e. Place the uniformly mixed powder from step d into a laser generator, using high-purity argon as a protective gas, and melt the powder using laser energy deposition to ensure the uniformity of the alloy coating.

[0049] f. Laser cladding layer is prepared by laser cladding process. The laser parameters are: laser power 1200w, scanning speed 400mm / min, powder feeding speed 10g / min, laser energy deposition method adopts single-layer multi-pass path, spot diameter 5mm, and overlap rate 50%.

[0050] (3) Heat treatment process:

[0051] The high-entropy alloy coating prepared in f was subjected to heat treatment as a post-treatment method. The heat treatment process was high-temperature annealing and holding for 1.0 h followed by water quenching.

[0052] Preferably, the heat treatment method for the high-entropy alloy coating is an annealing process, in which the coating is heated to 800°C, held at that temperature for 1.0 h, and then water quenched. Specifically, the temperature of the coating after laser cladding and cooling can be, for example, but not limited to, any one or any two of 600°C, 800°C, 1000°C, 1100°C, and 1300°C. The technical solution is described in detail below through Examples 1-3.

[0053] Example 1

[0054] This embodiment provides a process for preparing a high-entropy alloy coating, including the following steps:

[0055] (a) Select high-purity (≥99.9%) elemental powders of Al (5.96wt%), Co (13.01wt%), Cr (11.48wt%), Fe (12.33wt%), and Ni (57.22wt%), weigh them, and then ball-mill them for 4.0 h.

[0056] (b) Laser power 1200w, scanning speed 400mm / min, powder feeding speed 10g / min, laser energy deposition method adopts single-layer multi-pass path, spot diameter 5mm, overlap rate 50%, to prepare high-entropy alloy coating.

[0057] (c) The laser cladding coating from (b) is homogenized to 800°C;

[0058] (d) After holding in the heat treatment furnace for 1 hour, water quench and cool to room temperature.

[0059] Example 2

[0060] This embodiment provides a process for preparing a high-entropy alloy coating, including the following steps:

[0061] (a) Select high-purity (≥99.9%) elemental powders of Al (5.96wt%), Co (13.01wt%), Cr (11.48wt%), Fe (12.33wt%), and Ni (57.22wt%), weigh them, and then ball-mill them for 4.0 h.

[0062] (b) Laser power 1200w, scanning speed 400mm / min, powder feeding speed 10g / min, laser energy deposition method adopts single-layer multi-pass path, spot diameter 5mm, overlap rate 50%, to prepare high-entropy alloy coating.

[0063] (c) The laser cladding coating from (b) is homogenized to 1100°C;

[0064] (d) After holding in the heat treatment furnace for 1 hour, water quench and cool to room temperature.

[0065] Example 3

[0066] This embodiment provides a process for preparing a high-entropy alloy coating, including the following steps:

[0067] (a) Select high-purity (≥99.9%) elemental powders of Al (5.96wt%), Co (13.01wt%), Cr (11.48wt%), Fe (12.33wt%), and Ni (57.22wt%), weigh them, and then ball-mill them for 4.0 h.

[0068] (b) Laser power 1200w, scanning speed 400mm / min, powder feeding speed 10g / min, laser energy deposition method adopts single-layer multi-pass path, spot diameter 5mm, overlap rate 50%, to prepare high-entropy alloy coating.

[0069] (c) The laser cladding coating from (b) is homogenized to 1300°C;

[0070] (d) After holding in the heat treatment furnace for 1 hour, water quench and cool to room temperature.

[0071] In another specific embodiment, the present invention provides a TiC particle-reinforced AlCoCrFeNi 2.1 The preparation process of high-entropy alloy composite coatings includes the following steps:

[0072] (1) Raw material preparation:

[0073] a. Select high-purity (≥99.9%) Al (5.96-4.56wt%), Co (13.01-10.01wt%), Cr (11.48-8.88wt%), Fe (12.88-9.53wt%), Ni (57.20-47.00wt%) metal element powders and TiC (1-20wt%) ceramic particle powders.

[0074] b. Weigh out the element powders and TiC powder according to the above proportions.

[0075] (2) Laser cladding process:

[0076] c. The substrate is made of Q235 low-carbon steel. The oxide layer on the surface of the substrate is removed using an angle grinder, and then it is polished. Oil stains and impurities are removed with alcohol, and the substrate is dried.

[0077] d. Mix the TiC powder prepared in step b with the metal element powder and perform high-energy ball milling under inert gas protection. The ball milling time is controlled at 4-8 hours to ensure that the TiC particles are uniformly distributed in the metal powder.

[0078] e. Place the uniformly mixed powder from step d into a laser generator, using high-purity argon as a protective gas, and melt the powder using laser energy deposition to ensure the uniformity of the alloy coating.

[0079] f. Laser cladding layer was prepared using laser cladding process. The laser parameters were: laser power 1200W, scanning speed 400mm / min, powder feeding speed 10g / min, and laser energy deposition method using a single-layer multi-pass path with a spot diameter of 5mm and an overlap rate of 50%.

[0080] Table 1 Laser process parameters of the embodiments

[0081]

[0082] Preferably, the chemical composition of the metal powder is as follows (mass fraction): Al (5.96-4.56 wt%), Co (13.01-10.01 wt%), Cr (11.48-8.88 wt%), Fe (12.88-9.53 wt%), Ni (57.20-47.00 wt%), and TiC (1-20 wt%).

[0083] Preferably, the coating is a high-entropy alloy composite coating, for example, but not limited to, the addition of any one of TiC (1 wt%), TiC (5 wt%), TiC (15 wt%), and TiC (20 wt%). The more TiC particles added, the more lattice distortion is caused by the solid solution of TiC. Lattice distortion increases the resistance to dislocation movement, making slip more difficult. This improves the strength and hardness of the coating. This technical solution is described in detail below through Examples 4-7.

[0084] Example 4

[0085] This embodiment provides a preparation process for a high-entropy alloy composite coating, including the following steps:

[0086] (a) High-purity (≥99.9%) elemental powders of Al (5.89wt%), Co (12.86wt%), Cr (11.35wt%), Fe (12.19wt%), Ni (56.71wt%), and TiC (1wt%) were selected;

[0087] (b) Weigh the elemental powder and TiC granular powder and then ball mill them at high energy for 4.0 h;

[0088] (c) A high-entropy alloy coating was prepared by using a laser power of 1200W, a scanning speed of 400mm / min, a powder feeding speed of 10g / min, a single-layer multi-pass laser energy deposition method, a spot diameter of 5mm, and an overlap rate of 50%.

[0089] Example 5

[0090] This embodiment provides a preparation process for a high-entropy alloy composite coating, including the following steps:

[0091] (a) High-purity (≥99.9%) elemental powders of Al (5.89wt%), Co (12.86wt%), Cr (11.35wt%), Fe (12.19wt%), Ni (56.71wt%), and TiC (5wt%) were selected;

[0092] (b) Weigh the elemental powder and TiC granular powder and then ball mill them at high energy for 4.0 h;

[0093] (c) A high-entropy alloy coating was prepared by using a laser power of 1200W, a scanning speed of 400mm / min, a powder feeding speed of 10g / min, a single-layer multi-pass laser energy deposition method, a spot diameter of 5mm, and an overlap rate of 50%.

[0094] Example 6

[0095] This embodiment provides a preparation process for a high-entropy alloy composite coating, including the following steps:

[0096] (a) High-purity (≥99.9%) elemental powders of Al (5.89wt%), Co (12.86wt%), Cr (11.35wt%), Fe (12.19wt%), Ni (56.71wt%), and TiC (10wt%) were selected;

[0097] (b) Weigh the elemental powder and TiC granular powder and then ball mill them at high energy for 4.0 h;

[0098] (c) A high-entropy alloy coating was prepared by using a laser power of 1200W, a scanning speed of 400mm / min, a powder feeding speed of 10g / min, a single-layer multi-pass laser energy deposition method, a spot diameter of 5mm, and an overlap rate of 50%.

[0099] Example 7

[0100] This embodiment provides a preparation process for a high-entropy alloy composite coating, including the following steps:

[0101] (a) High-purity (≥99.9%) elemental powders of Al (5.89wt%), Co (12.86wt%), Cr (11.35wt%), Fe (12.19wt%), Ni (56.71wt%), and TiC (200wt%) were selected;

[0102] (b) Weigh the elemental powder and TiC granular powder and then ball mill them at high energy for 4.0 h;

[0103] (c) A high-entropy alloy coating was prepared by using a laser power of 1200W, a scanning speed of 400mm / min, a powder feeding speed of 10g / min, a single-layer multi-pass laser energy deposition method, a spot diameter of 5mm, and an overlap rate of 50%.

[0104] In a more specific implementation, the present invention provides a process for preparing a high-entropy alloy composite coating by heat treatment and the addition of TiC particles. The technical solution is described in detail below through Examples 8-9.

[0105] Example 8

[0106] This embodiment provides a preparation process for a high-entropy alloy composite coating, including the following steps:

[0107] (a) Select high-purity (≥99.9%) elemental powders of Al (5.89wt%), Co (12.86wt%), Cr (11.35wt%), Fe (12.19wt%), Ni (56.71wt%) and TiC (1wt%);

[0108] (b) Weigh the elemental powder and TiC granular powder and then ball mill them at high energy for 4.0 h;

[0109] (c) A high-entropy alloy coating was prepared by using a laser power of 1200W, a scanning speed of 400mm / min, a powder feeding speed of 10g / min, a single-layer multi-pass laser energy deposition method, a spot diameter of 5mm, and an overlap rate of 50%.

[0110] (d) The laser cladding coating from (c) is homogenized to 1100°C;

[0111] (e) After holding in the heat treatment furnace for 1 hour, water quench and cool to room temperature.

[0112] Example 9

[0113] This embodiment provides a preparation process for a high-entropy alloy composite coating, including the following steps:

[0114] (a) Select high-purity (≥99.9%) elemental powders of Al (5.89wt%), Co (12.86wt%), Cr (11.35wt%), Fe (12.19wt%), Ni (56.71wt%) and TiC (5wt%);

[0115] (b) Weigh the elemental powder and TiC granular powder and then ball mill them at high energy for 4.0 h;

[0116] (c) A high-entropy alloy coating was prepared by using a laser power of 1200W, a scanning speed of 400mm / min, a powder feeding speed of 10g / min, a single-layer multi-pass laser energy deposition method, a spot diameter of 5mm, and an overlap rate of 50%.

[0117] (d) The laser cladding coating from (c) is homogenized to 1100°C;

[0118] (e) After holding in the heat treatment furnace for 1 hour, water quench and cool to room temperature.

[0119] Comparative Example 1

[0120] This comparative example provides a process for preparing a high-entropy alloy coating, including the following steps:

[0121] (a) Select high-purity (≥99.9%) elemental powders of Al (5.96wt%), Co (13.01wt%), Cr (11.48wt%), Fe (12.33wt%), and Ni (57.22wt%), weigh them, and then ball-mill them for 4.0 h.

[0122] (b) Laser power 1200w, scanning speed 400mm / min, powder feeding speed 10g / min, laser energy deposition method adopts single-layer multi-pass path, spot diameter 5mm, overlap rate 50%, to prepare high-entropy alloy coating.

[0123] Comparative Example 2

[0124] This comparative example provides a preparation process for a high-entropy alloy composite coating, including the following steps:

[0125] (a) High-purity (≥99.9%) elemental powders of Al (5.89wt%), Co (12.86wt%), Cr (11.35wt%), Fe (12.19wt%), Ni (56.71wt%), and TiC (0wt%) were selected;

[0126] (b) Weigh the elemental powder and TiC granular powder and then ball mill them at high energy for 4.0 h;

[0127] (c) A high-entropy alloy coating was prepared by using a laser power of 1200W, a scanning speed of 400mm / min, a powder feeding speed of 10g / min, a single-layer multi-pass laser energy deposition method, a spot diameter of 5mm, and an overlap rate of 50%.

[0128] Comparative Example 3

[0129] This comparative example provides a preparation process for a high-entropy alloy composite coating, including the following steps:

[0130] (a) Select high-purity (≥99.9%) elemental powders of Al (5.89wt%), Co (12.86wt%), Cr (11.35wt%), Fe (12.19wt%), and Ni (56.71wt%).

[0131] (b) Weigh the elemental powder and then ball mill it at high energy for 4.0 h;

[0132] (c) A high-entropy alloy coating was prepared by using a laser power of 1200W, a scanning speed of 400mm / min, a powder feeding speed of 10g / min, a single-layer multi-pass laser energy deposition method, a spot diameter of 5mm, and an overlap rate of 50%.

[0133] (d) The laser cladding coating from (c) is homogenized to 1100°C;

[0134] (e) After holding in the heat treatment furnace for 1 hour, water quench and cool to room temperature.

[0135] To facilitate differentiation of the samples in the following examples, each sample is named according to its powder characteristics or process sequence. For example, sample T10 represents AlCoCrFeNi with 10wt% TiC added. 2.1 EHEA coated specimen. Specimen #3 represents AlCoCrFeNi coated at a heat treatment temperature of 1000℃. 2.1 EHEA coated sample. C1 represents AlCoCrFeNi alloy with 1 wt% TiC added, heat treated at 1100℃. 2.1 EHEA coated specimen.

[0136] Microhardness and tribological tests were performed on the samples from each embodiment and comparative example. The microhardness was characterized at room temperature through microhardness measurement and tribological testing. The Vickers hardness of the coating was measured using a digital microhardness tester with a load of 300g and a residence time of 15 seconds. The average value of five measurements for each sample was recorded. Based on the microhardness test results from each embodiment and comparative example of the present invention, it can be seen that the hardness of the samples (Examples 1-3) at 800℃-1300℃ is significantly lower than that of the untreated sample (Comparative Example 1). Figure 2 As shown, the microhardness values ​​of the samples are 198 HV. 0.3 290HV 0.3 322HV 0.3 281HV 0.3 and 167HV 0.3 Except for the sample at 1300℃, which had the lowest hardness, the hardness of all other heat-treated samples was higher than that of the untreated samples. According to ASTM G99-04, the sliding dry wear behavior of the coating was evaluated at room temperature using a ball-and-disc tribometer (MDW-02). SiC grinding balls were used, and the test was conducted for 30 minutes at a distance of 5 mm, a speed of 3 m / min, and a load of 20 N. Figure 2 As shown, the friction coefficient was lowest after heat treatment at 800℃ (Example 1, #2). Figure 5 As shown, the hardness of samples T1-T20 (Examples 4-6) is 219.3 HV. 0.3 231.3HV 0.3 247.7HV 0.3 253.9HV 0.3 The hardness of the samples treated at HTT was greater than that of the T0 (Comparative Example 2) sample. However, when HTT was increased again to 1300℃, the microstructure coarsening became more severe, and the difference in the amount of the two phases increased. The austenite grains in the microstructure of the sample treated at 1300℃ were abnormally large, indicating that overheating had occurred. This is the main reason why the hardness of Example 3 was lower than that of Comparative Example 1. Figure 7As shown, AlCoCrFeNi alloy with 5wt% TiC was heat-treated at 1100℃. 2.1 The EHEA coating (C2 Example 9) exhibits the highest hardness compared to C0 and C1 (Comparative Examples 3 and 8), reaching 386.4 HV. 0.3 .

[0137] Meanwhile, SEM (scanning electron microscopy) and EBSD (electron backscattering diffraction) methods were used to analyze 1#-

[0138] The magnified structural morphology of the four samples was obtained by SEM observation, such as... Figure 1 The samples shown all exhibited columnar and dendritic features in the initial FCC and BCC phases. Table 1 shows the elemental composition of the initial FCC and BCC phases. Ni and Al were enriched in the BCC phase, Fe and Cr were enriched in the FCC phase, and Co was uniformly distributed in all phases. At HTT (heat-treatment temperature) = 800℃, short particles began to appear in the FCC phase, which were considered to be precipitates generated by heat treatment. At HTT = 1000℃, the short particles in the FCC phase became needle-like and short blocky and became coarse. When HTT = 1200℃, the needle-like precipitates disappeared, while the short blocky precipitates remained. When HTT = 1300℃, no precipitates were observed. Furthermore, with increasing HTT, the initial BCC in the coating became increasingly coarse.

[0139] Table 2. Deposited AlCoCrFeNi 2.1 Chemical elemental composition (wt.%) of the initial FCC and BCC phases in EHEA.

[0140]

[0141] Figure 4 The overall SEM morphology of the cross-section of the composite coating with 1-20 wt% TiC is shown. All elements are macroscopically uniformly distributed, with no segregation or ablation of low-melting-point elements. Light gray granular phases of different morphologies and sizes are distributed between columnar and dendritic structures. The microstructure of the coating is further observed using a higher magnification SEM. Figure 4 As shown in (a1), (b1), (c1), and (d1), EDS surface scanning confirmed that the light gray particles were TiC, and the particle size increased with increasing TiC content. At a TiC content of 1 wt%, the TiC particles exhibited a polygonal morphology. At a TiC content of 5 wt%, the TiC precipitates formed approximately spherical particles. With further increases in TiC content, the nucleation rate significantly improved. A large amount of TiC tended to grow on smaller TiC particles, forming larger, petal-like TiC structures.

[0142] Figure 6EBSD images of composite coatings with 1-5 wt% TiC added and heat-treated at 1100 °C are shown. Due to the combined effect of TiC particle addition and heat treatment, the grain size of the coating microstructure is refined. The texture index in the pole figure (PF) can reflect the bonding strength of the coating to some extent. The texture index of the composite coatings with heat treatment and 1-5 wt% TiC particles (Examples 7-8) is higher than that of the untreated coating and the coating without TiC particles (Comparative Example 3). This indicates that heat treatment and the addition of TiC particles can enhance the bonding strength of the coating.

[0143] This invention prepares AlCoCrFeNi using a laser cladding process through heat treatment and the addition of TiC particles. 2.1 The EHEA coating, while maintaining the FCC+BCC dual-phase eutectic microstructure, improves the coating's microhardness and wear resistance. It refines the grains, resulting in a more uniform microstructure. The process can be adjusted according to application requirements to obtain high-entropy alloy coatings with different properties, facilitating industrial-scale application.

[0144] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the content of the present invention under the concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for preparing a high-entropy alloy composite coating material, characterized in that, Includes the following steps: (1) Weigh each powder according to the following high-entropy alloy composite coating material ratio, and perform high-energy ball milling under inert gas protection to obtain mixed powder; The high-entropy alloy composite coating material comprises, by weight percentage: Al 4.56-5.96wt% Co 10.01-13.01wt% Cr 8.88-11.48wt% Fe 9.53-12.88wt% Ni 47.00-57.22wt% TiC 1-20 wt% (2) For the mixed powder obtained in step (1), a high-entropy alloy coating is prepared by laser cladding process; (3) The high-entropy alloy coating prepared in step (2) is subjected to heat treatment at a temperature of 800-1100℃ for 1.0-1.2 h. After the heat treatment is completed, it is quenched in water to room temperature to obtain the high-entropy alloy composite coating material.

2. The preparation method according to claim 1, characterized in that, The purity of Al, Co, Cr, Fe, Ni and TiC is ≥99.9%.

3. The preparation method according to claim 1, characterized in that, The high-energy ball mill operates at a speed of 200-500 r / min, with a milling time of 4-8 h and a ball-to-material weight ratio of 1:5-1:

10.

4. The preparation method according to claim 1, characterized in that, The laser cladding process has a laser power of 1200-2300 W, a scanning speed of 400-1000 mm / min, a powder feeding speed of 10-20 g / min, and uses a single-layer multi-pass laser energy deposition method with a spot diameter of 3-5 mm and an overlap rate of 50%.

5. The preparation method according to claim 1, characterized in that, The mass percentage of TiC is 1-5 wt%.

6. The preparation method according to claim 1, characterized in that, The TiC mass percentage is 1-5 wt%, and the heat treatment temperature is 1100℃.

7. The high-entropy alloy composite coating material prepared by the preparation method according to any one of claims 1-6.

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