A multi-element reinforced phase nickel-based wear-resistant coating and a preparation method and application thereof

Abstract

The application provides a multi-element reinforced phase nickel-based wear-resistant coating and a preparation method and application thereof, and relates to the technical field of alloy coating preparation. The TC4 titanium alloy base body is pretreated to obtain a pretreated base body; a protective gas is introduced, and a composite cladding powder is arranged on the surface of the pretreated base body by laser cladding in a coaxial powder feeding mode to obtain a multi-element reinforced phase nickel-based wear-resistant coating; and the composite cladding powder comprises IN718 nickel-based high-temperature alloy powder and nickel-coated tungsten carbide powder. In the cladding, a TiN reinforced phase is generated in situ, and the nickel-coated WC is partially decomposed to form TiC, W2C and the like, thereby constructing a multi-element reinforced phase system with the undecomposed WC. The multi-element reinforced phase nickel-based wear-resistant coating can realize good metallurgical bonding with the TC4 titanium alloy base body, reduce the hardness fluctuation amplitude, and significantly improve the wear resistance, microstructure stability and service reliability of the coating.

Description

Technical Field

[0001] This application relates to the field of alloy coating preparation technology, and in particular to a multi-component reinforced phase nickel-based wear-resistant coating, its preparation method and application. Background Technology

[0002] Existing single-phase tungsten carbide (WC) reinforced nickel-based cladding layers suffer from particle agglomeration and large hardness gradients along the cross-section. Under alternating loads, the hard phase detaches, leading to localized corrosion, making them unsuitable for heavy-duty moving parts in marine and aerospace applications. TC4 titanium alloy (Ti-6Al-4V), on the other hand, is the most widely used α-β type dual-phase titanium alloy, accounting for over 75% of total titanium alloy consumption. Due to its excellent properties such as low density, high specific strength, and corrosion resistance, it is widely used in aerospace, marine engineering, and other fields. However, TC4 titanium alloy has low surface hardness and insufficient wear resistance, making it prone to wear during long-term service, leading to surface failure of components and limiting its further application in complex working conditions and harsh environments.

[0003] To improve the wear resistance of titanium alloy parts and reduce the risk of wear failure, existing technologies typically employ surface modification techniques such as thermal spraying and vapor deposition to prepare protective coatings on the titanium alloy surface. While these methods can improve the wear resistance of titanium alloy surfaces to some extent, they still have certain limitations. For example, coatings prepared using thermal spraying technology are usually non-metallurgically bonded to the substrate, resulting in limited bonding strength and a tendency to peel off under complex load conditions. Vapor deposition technology, on the other hand, is limited by coating thickness and deposition efficiency, making it difficult to obtain protective layers that meet the requirements of high-load and high-wear environments, thus failing to meet the application requirements under harsh service conditions.

[0004] Laser cladding, a high-energy beam surface modification technology, uses a high-energy laser beam to simultaneously melt high-performance metal powder with a substrate surface, forming a metallurgically bonded functional coating. The resulting coating offers advantages such as controllable thickness, dense structure, and adjustable composition, making it widely used in the manufacture of critical components. However, when using laser cladding to prepare wear-resistant coatings on TC4 titanium alloy substrates, a significant fluctuation in hardness between the coating and substrate surfaces remains a problem. This leads to substantial differences in the wear resistance of the coating across different regions, increasing the difficulty of accurately assessing and predicting its wear service life.

[0005] Therefore, there is an urgent need to develop a coating preparation method using laser cladding to solve the above problems. Summary of the Invention

[0006] The purpose of this application is to provide a multi-component reinforced phase nickel-based wear-resistant coating, its preparation method, and TC4 titanium alloy products, so as to solve the problems of uneven distribution of reinforcing phase, large fluctuation of hardness, severe local regeneration of reinforcing phase, and insufficient wear resistance and service stability in existing nickel-based wear-resistant coatings.

[0007] To achieve the above objectives, this application provides a method for preparing a multi-component reinforced phase nickel-based wear-resistant coating, comprising the following steps:

[0008] The TC4 titanium alloy substrate is pretreated to obtain a pretreated substrate; nitrogen gas is introduced as a reactive protective gas to participate in the subsequent nitriding reaction; composite cladding powder is placed on the surface of the pretreated substrate by laser cladding using a coaxial powder feeding method to obtain a nickel-based wear-resistant coating.

[0009] Furthermore, the composite cladding powder includes IN718 nickel-based superalloy powder and nickel-coated tungsten carbide powder; the particle size of the IN718 nickel-based superalloy powder is 150-300 mesh, the particle size of the nickel-coated tungsten carbide powder is 100-270 mesh, and the mass ratio of the IN718 nickel-based superalloy powder to the nickel-coated tungsten carbide powder is (80-95):(5-20).

[0010] Furthermore, the chemical composition of the IN718 nickel-based superalloy powder, by mass percentage, includes: Ni 50%-55%, Cr 18%-22%, Nb 4%-6%, Mo 2%-4%, Ti 0.5%-1.5%, Al 0.2%-1.0%, with the remainder being Fe and unavoidable impurities; the nickel-coated tungsten carbide powder is spherical tungsten carbide particles with a surface electroless nickel plating, and its chemical composition, by mass percentage, includes: Ni 35%-45%, with the remainder being tungsten carbide.

[0011] Furthermore, the chemical composition of the TC4 titanium alloy matrix, in parts by mass, includes:

[0012] Al 5.5%-6.75%, V 3.5%-4.5%, Fe≤0.30%, O≤0.20%, C≤0.08%, N≤0.05%, H≤0.015%, Si≤0.1%, balance Ti.

[0013] Furthermore, the pretreatment process of the TC4 titanium alloy substrate is as follows: first, the surface of the TC4 titanium alloy substrate is mechanically polished with 60-grit sandpaper to remove surface oxides and impurities, then anhydrous ethanol is used for cleaning to remove residual debris on the surface, and the substrate is placed in an ultrasonic cleaner and ultrasonically cleaned with acetone for 5 minutes.

[0014] Furthermore, the composite cladding powder is dried before use at a temperature of 90℃-150℃ for a time of 90min-120min.

[0015] Furthermore, the laser power of the laser cladding is 800W-1200W, the scanning speed is 360mm / min-480mm / min, the powder feeding rate is 20g / min-22g / min, the spot diameter is 4.1mm-4.2mm, and the flow rate of the protective gas is 8L / min-10L / min. If the scanning speed is lower than 360mm / min, the heat input will be too high, resulting in excessive WC decomposition, excessive W2C, and embrittlement of the coating. If the scanning speed is higher than 480mm / min, the powder will not melt completely, resulting in porosity defects.

[0016] The second aspect of this application provides a multi-component reinforced phase nickel-based wear-resistant coating, which is prepared by the preparation method of the multi-component reinforced phase nickel-based wear-resistant coating;

[0017] The multi-component reinforced nickel-based wear-resistant coating is applied to the surface of the TC4 titanium alloy substrate and undergoes element interdiffusion at the interface with the TC4 titanium alloy substrate to form a continuous and dense metallurgical bonding layer.

[0018] Furthermore, the multi-component reinforced nickel-based wear-resistant coating simultaneously satisfies the following conditions:

[0019] A. The thickness of the multi-component reinforced nickel-based wear-resistant coating is 1.25mm-2mm;

[0020] B. The microstructure of the multi-component reinforced nickel-based wear-resistant coating includes cellular crystals, dendritic crystals, and reinforcing phases distributed in the grain boundaries and intergranular regions;

[0021] C. The phase composition of the multi-component reinforced nickel-based wear-resistant coating includes: TiN, TiC, α-Ti, W2C, Cr7C3, Ti(C,N), Ni3Ti, and (W,Ti)C. 1-x .

[0022] The third aspect of this application provides an application of a multi-component reinforced phase nickel-based wear-resistant coating to a titanium alloy product, wherein the wear-resistant coating is prepared on the surface of a TC4 titanium alloy component for manufacturing titanium alloy parts that are subjected to heavy loads and high-temperature alternating friction conditions for a long time.

[0023] Compared with the prior art, the beneficial effects of this application include:

[0024] This application presents a method for preparing a multi-component reinforced nickel-based wear-resistant coating. It proposes a laser cladding technology route based on the synergistic reinforcement of multiple ceramic reinforcing phases, used to prepare nickel-based composite wear-resistant coatings with small hardness fluctuation amplitudes and excellent wear resistance. Compared to traditional single-reinforcing-phase systems, this application introduces multiple ceramic reinforcing phases with significant density differences. By utilizing the influence of the internal temperature gradient of the molten pool and the molten pool convection behavior on the migration law of different reinforcing phases, the spatial distribution of the reinforcing phases in the cladding layer is controlled. This effectively suppresses the local segregation phenomenon easily caused by a single reinforcing phase and the resulting uneven hardness distribution, reduces the hardness fluctuation amplitude of the coating from the surface to the substrate, improves the uniformity of the coating structure, reduces the cross-sectional hardness difference, suppresses local spalling failure under alternating loads, and extends the overhaul cycle of heavy-duty components.

[0025] Furthermore, this application uses nitrogen as a protective gas. Nitrogen ionizes in the high-temperature molten pool environment of laser cladding to form active nitrogen atoms, promoting the reaction between Ti and N elements in situ to synthesize the TiN reinforcing phase. Simultaneously, during the cooling phase of the molten pool, the nickel-coated WC particles partially decompose under the high energy of the laser. The released C elements react with Ti elements in the TC4 matrix to form the TiC reinforcing phase, while some WC phases undergo decarburization to generate the W2C reinforcing phase. The incompletely decomposed WC particles exist in a dispersed form within the cladding layer. Since TiC and TiN have similar crystal structures and lattice constants, they readily form a Ti(C,N) solid solution, further enhancing the interfacial bonding between the reinforcing phase and the matrix. Ultimately, a multi-scale synergistic reinforcement system composed of TiN, TiC, W2C, Ti(C,N) reinforcing phases, and a nickel-based solid solution is formed within the coating. Among them, high-hardness ceramic phases such as TiN, TiC, and W2C possess high hardness, which can significantly improve the coating's hardness, resistance to plastic deformation, and wear resistance. They construct a multi-scale ceramic reinforcement framework, greatly enhancing the coating's resistance to plastic shear. Dispersed reinforcing particles can effectively hinder dislocation movement, inhibit crack initiation and propagation, and improve the cladding layer's load-bearing capacity against external loads. The nickel-based solid solution matrix provides necessary plasticity and toughness support, which helps alleviate the stress concentration problem caused by the large-scale introduction of hard phases. Through dispersion reinforcement, grain refinement reinforcement, and synergistic load-bearing effects, the above-mentioned multi-component reinforcing phases achieve a balance between high hardness and good toughness in the coating. While improving wear resistance, they effectively avoid problems such as local embrittlement and reinforcing phase segregation that are prone to occur in single-reinforcing-phase systems, thereby significantly improving the coating's microstructure stability and service reliability.

[0026] Furthermore, this application investigates the regulatory effect of laser power on the microstructure evolution, reinforcing phase distribution behavior, and service performance of the cladding layer. By adjusting the laser power, this application can effectively control the heat input of the molten pool, thereby optimizing the generation and distribution of the reinforcing phase and obtaining a coating with a dense microstructure and a gentle hardness gradient.

[0027] The method provided in this application not only effectively solves the problems of uneven distribution of reinforcing phase, large fluctuation of hardness, and insufficient service stability in existing nickel-based wear-resistant coatings, but also provides new technical ideas and theoretical basis for the design of wear-resistant coating systems with coordinated reinforcement of multi-element ceramic reinforcing phases, optimization of laser cladding process, and development of high-performance wear-resistant surface engineering materials, and has good engineering application prospects. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0029] Figure 1 A schematic diagram of the preparation method of the multi-component reinforced phase nickel-based wear-resistant coating provided in Example 1;

[0030] Figure 2 The images show the cross-sectional macroscopic morphology of the multi-component reinforced phase nickel-based wear-resistant coatings prepared in the examples; (a) is the cross-sectional macroscopic morphology of the multi-component reinforced phase nickel-based wear-resistant coating prepared in Example 1; (b) is the cross-sectional macroscopic morphology of the multi-component reinforced phase nickel-based wear-resistant coating prepared in Example 2; and (c) is the cross-sectional macroscopic morphology of the multi-component reinforced phase nickel-based wear-resistant coating prepared in Example 3.

[0031] Figure 3 The images show the XRD patterns of the multi-component reinforced phase nickel-based wear-resistant coatings prepared in Examples 1, 2, and 3.

[0032] Figure 4 SEM images of the multi-component reinforced phase nickel-based wear-resistant coatings prepared in Examples 1, 2 and 3;

[0033] Figure 5 The image shows the microhardness distribution curves of the multi-component reinforced phase nickel-based wear-resistant coatings prepared in Examples 1, 2, and 3. Detailed Implementation

[0034] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0035] The first aspect of this application provides a method for preparing a multi-component reinforced phase nickel-based wear-resistant coating, comprising:

[0036] The TC4 titanium alloy matrix was pretreated to obtain the pretreated matrix.

[0037] Nitrogen gas was introduced as a protective gas. First, the surface of the TC4 titanium alloy substrate was mechanically polished with 60-grit sandpaper to remove oxides and impurities. Then, anhydrous ethanol was used to clean the surface to remove residual debris. The substrate was then placed in an ultrasonic cleaner and ultrasonically cleaned with acetone for 5 minutes to obtain a pretreated substrate. Nitrogen gas was then introduced as a protective gas. Composite cladding powder (100-300 mesh) was laser-clad onto the surface of the pretreated substrate using a coaxial powder feeding method to obtain a multi-component reinforced phase nickel-based wear-resistant coating.

[0038] The composite cladding powder includes IN718 powder (150-300 mesh) and nickel-plated WC powder (100-270 mesh). The mass ratio of the IN718 nickel-based high-temperature alloy powder to the nickel-plated tungsten carbide powder is (80-95):(5-20) by mass percentage.

[0039] It should be noted that, to ensure excellent service stability of the wear-resistant coating, the formed coating must form a good metallurgical bond with the TC4 titanium alloy substrate. During the laser cladding process, a micro-melt layer structure will form on the substrate surface near the molten pool boundary. This micro-melt layer structure refers to a transitional layer formed when the substrate material undergoes localized melting (partial melting) and rapid resolidification due to a local temperature exceeding the solidus line but below the liquidus line. This layer, located between the fully melted zone and the unmelted substrate, is typically thin and effectively mitigates the thermophysical property differences between the cladding layer and the substrate, reduces interfacial thermal stress concentration, and improves the metallurgical bond strength between the cladding layer and the substrate, thereby enhancing the overall structural stability and service reliability of the wear-resistant coating.

[0040] It should also be noted that after the nickel-based composite powder is uniformly fed into the laser molten pool, the high-energy laser causes the powder and the surface of the TC4 titanium alloy matrix to melt rapidly, forming a localized molten pool. During the melting process, elements such as Ni, Cr, and Fe in the IN718 powder undergo solid solution with elements such as Ti, Al, and V in the TC4 matrix. At the same time, the nickel-coated WC particles undergo partial decomposition and element diffusion under the action of the high-temperature molten pool, ultimately forming a composite structure composed of nickel-based solid solution and multi-component strengthening phases.

[0041] Specifically, nitrogen is used as a protective gas, creating a localized high-temperature environment in the molten pool region under the action of a high-energy laser. Nitrogen ionizes to form active nitrogen atoms, and the Ti elements released from the local melting of the TC4 matrix undergo an in-situ metallurgical reaction with these active nitrogen atoms to generate a TiN strengthening phase. The TiN strengthening phase possesses high hardness and thermal stability, significantly improving the coating's hardness and resistance to abrasive wear. Simultaneously, nickel-coated tungsten carbide particles undergo partial decarburization under the high energy of the laser. The released active C atoms react with molten Ti elements to form a TiC strengthening phase, while some WC particles decarburize to form a W2C strengthening phase. Incompletely decomposed WC particles are dispersed throughout the cladding layer. Because TiC and TiN have similar crystal structures and lattice constants, they readily undergo a solid solution reaction to form a Ti(C,N) solid solution, further enhancing the coating's hardness, thermal stability, and wear resistance.

[0042] Furthermore, the formed reinforcing phases such as TiN, TiC, and W2C constitute a multi-scale synergistic reinforcement system with the nickel-based solid solution. Among them, the high-hardness ceramic phases such as TiN and W2C can significantly improve the coating hardness and resistance to plastic deformation; the in-situ synthesized TiC particles, as a dispersed reinforcing phase, can effectively hinder dislocation movement, suppress crack propagation, and improve load-bearing capacity; the nickel-based solid solution matrix provides the necessary plasticity and toughness support, thereby achieving a synergistic match between high hardness and good toughness, and avoiding the local embrittlement phenomenon that is prone to occur in single-reinforcing-phase systems.

[0043] In some embodiments, the composite cladding powder comprises IN718 nickel-based superalloy powder and nickel-coated tungsten carbide powder, wherein the chemical composition of the IN718 nickel-based superalloy powder, in mass percentage, comprises:

[0044] Ni 50%-55%, Cr 18%-22%, Nb 4%-6%, Mo 2%-4%, Ti 0.5%-1.5%, Al 0.2%-1.0%, with the remainder being Fe and unavoidable impurities.

[0045] In some embodiments, the mass percentage of Ni in the IN718 nickel-based superalloy powder can be any value between 50%, 52%, 53%, 54%, 55%, or 50%-55%; the mass percentage of Cr can be any value between 18%, 19%, 20%, 21%, 22%, or 18%-22%; the mass percentage of Nb can be any value between 4%, 4.5%, 5%, 5.5%, 6%, or 4%-6%; the mass percentage of Mo can be any value between 2%, 2.5%, 3%, 3.5%, 4%, or 2%-4%; the mass percentage of Ti can be any value between 0.5%, 0.8%, 1.0%, 1.5%, or 0.5%-1.5%; and the mass percentage of Al can be any value between 0.2%, 0.5%, 0.8%, 1.0%, or 0.2%-1.0%.

[0046] It is important to note that using IN718 nickel-based superalloy powder as the matrix material for the cladding layer can effectively alleviate the thermal stress concentration problem caused by the large difference in thermal expansion coefficients between TC4 titanium alloy and the hard ceramic phase. Ni, as the main matrix element in IN718, is beneficial for forming a continuous and dense nickel-based solid solution, improving the plasticity and crack resistance of the cladding layer. Cr promotes the formation of stable carbide phases, improving the oxidation resistance and high-temperature wear resistance of the cladding layer. Nb and Mo enhance the solid solution strengthening effect, improving the coating strength and high-temperature stability. Therefore, by rationally controlling the proportions of each element in the IN718 powder, a nickel-based cladding layer with high hardness, high toughness, and excellent metallurgical bonding can be formed, providing a foundation for the excellent service performance of multi-component reinforced phase nickel-based wear-resistant coatings. If the proportions of the above elements deviate from the specified range, it may lead to insufficient precipitation of the reinforcing phase, coarsening of the microstructure, and thus reduce the wear resistance and stability of the cladding layer.

[0047] In some embodiments, the nickel-coated tungsten carbide powder includes WC particles and a nickel layer coating the surface of the WC particles; in the nickel-coated tungsten carbide powder, the mass percentage of WC particles is 55%-65%, and the mass percentage of the nickel coating layer is 35%-45%.

[0048] It is important to note that the nickel cladding layer improves the wettability and interfacial compatibility between WC particles and the IN718 molten alloy, reduces the tendency of WC particles to agglomerate and detach during laser cladding, and enhances the uniformity of the reinforcing phase dispersion in the cladding layer. Under the high temperature of the laser, some WC particles undergo decarburization and decompose to form the W2C reinforcing phase. Simultaneously, the released active C atoms can react with Ti elements in the TC4 matrix to generate the TiC reinforcing phase in situ. The incompletely decomposed WC particles remain dispersed within the cladding layer, effectively improving its hardness and resistance to abrasive wear. Therefore, nickel-clad WC particles not only achieve external reinforcing phase reinforcement but also further promote the formation of multi-component reinforcing phases through in-situ reactions, thereby improving the overall mechanical properties and service stability of the coating.

[0049] In some embodiments, the chemical composition of the TC4 titanium alloy matrix, in mass percentage, includes:

[0050] Al 5.5%-6.75%, V 3.5%-4.5%, Fe≤0.30%, O≤0.20%, C≤0.08%, N≤0.05%, H≤0.015%, Si≤0.1%, balance Ti.

[0051] It is important to note that TC4 titanium alloy is a typical α+β type titanium alloy, where Al is the α-phase stabilizing element and V is the β-phase stabilizing element. Al enhances the precipitation ability of the α-phase, thereby improving the matrix hardness and high-temperature stability; V stabilizes the β-phase, improving the coating toughness and stress buffering capacity. During laser cladding, after the TC4 matrix partially melts, the molten Ti reacts with N atoms ionized in the protective gas to form a TiN strengthening phase in situ. Simultaneously, active C atoms in the molten pool react with Ti to form a TiC strengthening phase. Since TiN and TiC have similar crystal structures and lattice constants, they readily form a Ti(C,N) solid solution, further improving the hardness, wear resistance, and microstructure stability of the cladding layer.

[0052] The composite cladding powder is dried before use at a temperature of 90℃-150℃ for a time of 90min-120min.

[0053] In some embodiments, the drying temperature can be any value between 90°C, 120°C, 150°C, or 90-150°C, and the drying time can be any value between 90 min, 100 min, 110 min, 120 min, or 90-120 min.

[0054] The laser cladding process parameters include: laser power of 800W–1200W, scanning speed of 360mm / min–480mm / min, powder feeding rate of 20g / min–22g / min, spot diameter of 4.1mm–4.2mm, and protective gas flow rate of 8L / min–10L / min.

[0055] In some embodiments, the laser power can be any value between 800W, 1000W, and 1200W, or between 800W and 1200W; the scanning speed can be any value between 360mm / min, 380mm / min, 400mm / min, 420mm / min, 440mm / min, 460mm / min, 480mm / min, or between 360mm / min and 480mm / min; the spot diameter can be any value between 4.1mm, 4.15mm, 4.2mm, or between 4.1mm and 4.2mm; and the flow rate of the protective gas can be any value between 8L / min, 9L / min, 10L / min, or between 8L / min and 10L / min.

[0056] It is important to note that laser power is a key factor affecting the microstructure evolution and the stability of the reinforcing phase in the cladding layer. At lower laser powers, the degree of WC particle decomposition is lower, which is beneficial for maintaining a stable distribution of the reinforcing phase and improving wear resistance. As laser power increases, the molten pool temperature and residence time increase, leading to greater decarburization of WC, promoting W2C phase formation, and simultaneously enhancing the diffusion of carbon into the molten pool, resulting in increased TiC formation. However, excessively high laser power may lead to over-dissolution of the reinforcing phase, microstructure coarsening, and decreased hardness, thus affecting the overall performance of the coating. Therefore, by adjusting the laser power, an optimized balance between reinforcing phase formation behavior, microstructure uniformity, and wear resistance can be achieved.

[0057] The second aspect of this application provides a multi-component reinforced phase nickel-based wear-resistant coating, which is prepared by the preparation method of the multi-component reinforced phase nickel-based wear-resistant coating;

[0058] The multi-component reinforced nickel-based wear-resistant coating is applied to the surface of the TC4 titanium alloy substrate and undergoes element interdiffusion at the interface with the TC4 titanium alloy substrate to form a continuous and dense metallurgical bonding layer.

[0059] In some embodiments, the multi-component reinforced phase nickel-based wear-resistant coating simultaneously satisfies the following conditions:

[0060] A. The thickness of the multi-component reinforced phase nickel-based wear-resistant coating is 1.25mm-2.0mm;

[0061] In some embodiments, the thickness of the multi-component reinforced phase nickel-based wear-resistant coating can be any value between 1.25 mm, 1.35 mm, 1.45 mm, 1.55 mm, 1.65 mm, 1.75 mm, 1.85 mm, 1.95 mm, 2.0 mm, or 1.25-2.0 mm.

[0062] B. The microstructure of the multi-component reinforced nickel-based wear-resistant coating includes cellular crystals, dendritic crystals, and reinforcing phases distributed in the grain boundaries and intergranular regions;

[0063] C. The phase composition of the multi-component reinforced nickel-based wear-resistant coating includes: TiN, TiC, α-Ti, W2C, Cr7C3, Ti(C, N), Ni3Ti, and (W, Ti)C. 1-x .

[0064] It is worth noting that the multi-component reinforced nickel-based wear-resistant coating of this application has a specific phase composition. This phase composition is rationally designed and can achieve synergistic reinforcement of the multi-component reinforced phases during laser cladding, thereby obtaining excellent wear resistance and microstructure stability. On one hand, TiN, TiC, W2C, and (W,Ti)C... 1-x High-hardness ceramic reinforcing phases can significantly improve the hardness, resistance to plastic deformation, and wear resistance of coatings. Specifically, the TiN reinforcing phase is generated by the in-situ reaction of molten Ti and active N atoms in a TC4 matrix under nitrogen protection. TiC and Ti(C,N) solid solutions originate from the reaction of active C elements generated by WC decomposition with Ti elements, effectively improving the interfacial bonding between the reinforcing phase and the matrix and suppressing localized brittle fracture. On the other hand, Cr reacts with C to form the Cr7C3 hard phase, further improving the wear resistance and high-temperature stability of the coating; the Ni3Ti reinforcing phase helps improve the strength and microstructure stability of the nickel-based solid solution. Simultaneously, the α-Ti phase and the nickel-based solid solution together constitute a continuous matrix, providing necessary toughness support and load-bearing capacity for the hard phase, thereby alleviating the stress concentration problem caused by the introduction of a large amount of ceramic reinforcing phases.

[0065] In addition, TiN, TiC, Ti(C,N), W2C and (W,Ti)C 1-x Due to differences in density and formation mechanism, the reinforcing phases can form a relatively uniform spatial distribution under the action of molten pool convection and temperature gradient, reducing the tendency of reinforcing phase agglomeration and minimizing local hardness fluctuations. Therefore, this application constructs a multi-component synergistic reinforcement system composed of in-situ synthesized reinforcing phases and externally reinforced phases, achieving coating microstructure densification, reinforcing phase homogenization, and synergistic matching of hardness and toughness, thereby significantly improving the wear resistance and service reliability of multi-component reinforced phase nickel-based wear-resistant coatings.

[0066] The third aspect of this application provides an application of a multi-component reinforced phase nickel-based wear-resistant coating to a titanium alloy product, wherein the wear-resistant coating is prepared on the surface of a TC4 titanium alloy component for manufacturing titanium alloy parts that are subjected to heavy loads and high-temperature alternating friction conditions for a long time.

[0067] Example 1

[0068] This embodiment provides a multi-component reinforced phase nickel-based wear-resistant coating and its preparation method, the preparation process is as follows: Figure 1 As shown, the specific preparation steps are as follows:

[0069] S1: Using TC4 titanium alloy as the matrix, the chemical composition, based on 100% by mass, includes: 6.1% Al, 4.2% V, 0.3% Fe, 0.1% C, 0.05% N, 0.015% H, 0.2% O, with the remainder being Ti; IN718 nickel-based superalloy powder and nickel-coated tungsten carbide powder are weighed in a 9:1 ratio, mixed evenly, and dried in a vacuum drying oven at 120℃ for 2 hours. The chemical composition of IN718 nickel-based superalloy powder, based on 100% by mass, includes: 52.26% Ni, 19.87% Cr, 4.96% Nb, 2.86% Mo, 0.79% Ti, 0.48% Al, with the remainder being Fe; the chemical composition of nickel-coated tungsten carbide powder, based on 100% by mass, includes: 35%-45% Ni, with the remainder being WC.

[0070] S2: Roughen the surface of TC4 titanium alloy with sandpaper, and then clean the oil stains with acetone.

[0071] S3: After the cleaning process is completed, composite powder is laser-clad onto the TC4 titanium alloy substrate to obtain a wear-resistant coating. The laser cladding process parameters are: laser power 800W, scanning rate 420mm / min, powder feeding rate 20g / min, spot diameter 4.2mm, both protective gas and powder carrier gas are nitrogen, with a protective gas flow rate of 10L / min, and the thickness of the resulting wear-resistant coating is 1.25mm.

[0072] The formed multi-component reinforced nickel-based wear-resistant coating forms a good metallurgical bond with the surface of the TC4 titanium alloy substrate. Performance tests show that the hardness of the multi-component reinforced nickel-based wear-resistant coating prepared by laser cladding is significantly improved and the wear resistance is optimized compared with the TC4 titanium alloy substrate.

[0073] Example 2

[0074] The difference from Example 1 is that the laser power in step S3 is 1000W, while the other process parameters remain unchanged.

[0075] Example 3

[0076] The difference from Example 1 is that the laser power in step S3 is 1200W, while the other process parameters remain unchanged.

[0077] The coatings obtained in Examples 1-3 were tested for cross-sectional morphology, XRD phase composition, microstructure, microhardness, and tribological properties. The results are as follows: Figures 2-5 As shown.

[0078] The cross-sectional morphology of the multi-component reinforced phase nickel-based wear-resistant coatings prepared in Examples 1, 2, and 3 was tested, as follows: Figure 2 As shown, the left figure shows the cross-sectional morphology of the wear-resistant coating prepared in Example 1, the middle figure shows the cross-sectional morphology of the wear-resistant coating prepared in Example 2, and the right figure shows the cross-sectional morphology of the wear-resistant coating prepared in Example 3. Figure 2 As shown, the multi-component reinforced nickel-based wear-resistant coatings provided in Examples 1, 2, and 3 all form a good metallurgical bond with the TC4 titanium alloy substrate. The interface bonding area is continuous and dense, and there are basically no obvious defects such as pores or lack of fusion at the bonding site, indicating that the overall forming quality of the prepared coating is good. The thicknesses of Examples 1, 2, and 3 are 1.25 mm, 1.5 mm, and 2 mm, respectively, showing a trend of gradually increasing with increasing laser power. This is because as the laser power increases, the laser energy input to the molten pool per unit time increases, promoting the melting of more composite powder and part of the matrix material, thereby increasing the deposition amount of cladding material and ultimately leading to an increase in coating thickness. At the same time, higher laser power enhances the fluidity and convection mass transfer ability inside the molten pool, which is beneficial to the full spreading, wetting, and uniform deposition of molten powder on the substrate surface, thus further promoting the increase in cladding layer thickness.

[0079] It should be noted that appropriately increasing the coating thickness can improve the overall load-bearing capacity of the coating, giving it superior resistance to plastic deformation and fatigue failure under high contact stress or complex service load conditions. At the same time, a larger coating thickness can provide more sufficient wear allowance, thereby effectively extending the service life of the coating under friction and wear conditions. However, a larger coating thickness is not always better. Excessively high laser power may lead to excessive heat input, increasing the risk of microstructure coarsening and residual stress concentration, thus affecting the overall performance of the coating.

[0080] XRD phase analysis was performed on the multi-component reinforced nickel-based wear-resistant coatings prepared in Examples 1, 2, and 3. Specific results are as follows: Figure 3As shown, Example 1 corresponds to an 800W coating, Example 2 corresponds to a 1000W coating, and Example 3 corresponds to a 1200W coating (the same applies below). XRD analysis results show that in-situ generated TiN strengthening phases were detected in all three examples, indicating that under a nitrogen protective atmosphere, the surface of the TC4 titanium alloy substrate was locally heated and melted. The molten Ti element reacted with nitrogen atoms ionized in the nitrogen gas, generating an in-situ TiN strengthening phase, which was dispersed throughout the coating, thereby improving the coating's hardness and wear resistance. Further analysis revealed W2C diffraction peaks in Example 3. Combining scanning electron microscopy observations and surface XRD patterns after friction and wear, high laser power caused partial decarburization of WC particles, releasing active C atoms that reacted with Ti elements to generate a TiC strengthening phase. Since TiC and TiN have similar crystal structures and lattice constants, they readily undergo solid solution reactions to generate Ti(C, N) solid solutions, further enhancing the coating's hardness and wear resistance. XRD patterns showed an α-Ti phase, but no β-Ti phase was detected. This indicates that during the non-equilibrium solidification process of laser cladding, the high-temperature β phase transformed into the more thermodynamically stable α-Ti and Ni3Ti phases, forming a stable coating matrix structure. Therefore, by adjusting the laser power, the molten pool temperature and elemental reaction behavior can be effectively controlled, optimizing the formation and distribution of the reinforcing phase in the coating. This results in a dense, uniformly distributed reinforcing phase nickel-based wear-resistant coating with excellent hardness and wear resistance.

[0081] SEM images of the multi-component reinforced phase nickel-based wear-resistant coatings prepared in Examples 1, 2, and 3 are shown below. Figure 4As shown in the figure. The results show that the upper cladding region of the three sets of embodiments is mainly composed of dendritic crystals, equiaxed crystals, cellular crystals, and fine clustered dendrites. With the increase of laser power, the holding time of the molten pool becomes longer, resulting in grain coarsening, a gradual increase in coating grain size, and an increase in the amount of strengthening phase precipitation. The grain size of Example 3 is the largest, while that of Example 1 is the smallest. In the middle region, Example 1 mainly exhibits a regular network structure, Example 2 shows a uniform distribution of lath and cellular phases, and Example 3 shows a wheat-ear structure, indicating that with the increase of laser power, the structure in the middle of the coating gradually develops towards lath and wheat-ear shapes, and the grain morphology becomes more continuous and dense. For the lower region, the lower part of Example 1 exhibits a cross-sectional and cross-sectional skeleton-like network structure, which is more regular than the middle region. The lower part of Example 2 shows a dense wheat-ear structure with further grain refinement. The lower part of Example 3 is mainly composed of a titanium-rich carbide skeleton and a diffusely distributed TiN strengthening phase, with a dense, continuous overall structure and a uniform distribution of the strengthening phase. In summary, variations in laser power significantly influence the microstructure evolution of the coating. Appropriately increasing the laser power enhances the temperature uniformity and fluidity of the molten pool, facilitating the full diffusion and distribution of the reinforcing phase. Simultaneously, it regulates the precipitation morphology of the α-phase, leading to the formation of a multi-scale dense structure composed of dendritic, equiaxed, cellular, and terticular crystals. This structure not only improves the coating's hardness and wear resistance but also enhances its microstructure uniformity and service reliability, providing a microscopic basis for the superior performance of multi-component reinforcing phase nickel-based wear-resistant coatings.

[0082] Microhardness tests were performed on the multi-component reinforced nickel-based wear-resistant coatings prepared in Examples 1, 2, and 3. Specific results are as follows: Figure 5 As shown, the average microhardness of the 800W, 1000W, and 1200W coatings is 877 HV. 0.5 935HV 0.5 898HV 0.5 All of them are significantly higher than the matrix hardness (approximately 340 HV). 0.5 The microhardness was increased by approximately 2.58 times, 2.75 times, and 2.64 times respectively, resulting in superior wear resistance compared to the matrix. An excessively high heat input of 1200W led to excessive decomposition of WC, dissolution of the hard phase back into the molten pool, grain coarsening, and weakened dispersion strengthening effect, thus causing a decrease in microhardness.

[0083] The results show that laser power has a significant impact on the heat input of the molten pool, the solidification rate, and the stability of the reinforcing phase. Appropriate laser power can promote the refinement of cellular and dendritic structures, improve the uniformity of the dispersed distribution of the reinforcing phase, and reduce porosity and elemental segregation tendencies, thereby obtaining a wear-resistant coating with a dense structure, good interfacial bonding, and a gentler hardness gradient. However, excessively high laser power may lead to the decomposition of the reinforcing phase, coarsening of the structure, and a decrease in hardness. Therefore, this application achieves a comprehensive improvement in the coating's microstructure, hardness stability, and wear resistance by combining synergistic reinforcement with multi-element ceramic reinforcing phases with optimization of laser process parameters.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0085] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A method for preparing a multi-component reinforced nickel-based wear-resistant coating, characterized in that, Includes the following steps: The TC4 titanium alloy matrix was pretreated to obtain the pretreated matrix. Nitrogen gas is introduced as a reactive protective gas to participate in the subsequent nitriding reaction. The composite cladding powder is then applied to the pretreated substrate surface by laser cladding using a coaxial powder feeding method to obtain a nickel-based wear-resistant coating.

2. The method for preparing a multi-component reinforced phase nickel-based wear-resistant coating according to claim 1, characterized in that, The composite cladding powder includes IN718 nickel-based superalloy powder and nickel-coated tungsten carbide powder; the particle size of the IN718 nickel-based superalloy powder is 150-300 mesh, the particle size of the nickel-coated tungsten carbide powder is 100-270 mesh, and the mass ratio of the IN718 nickel-based superalloy powder to the nickel-coated tungsten carbide powder is (80-95):(5-20).

3. The method for preparing a multi-component reinforced phase nickel-based wear-resistant coating according to claim 2, characterized in that, The chemical composition of the IN718 nickel-based superalloy powder, by mass percentage, includes: Ni 50%-55%, Cr 18%-22%, Nb 4%-6%, Mo 2%-4%, Ti 0.5%-1.5%, Al 0.2%-1.0%, with the remainder being Fe and unavoidable impurities; the nickel-coated tungsten carbide powder is spherical tungsten carbide particles with a surface electroless nickel plating, and its chemical composition, by mass percentage, includes: Ni 35%-45%, with the remainder being tungsten carbide.

4. The method for preparing a multi-component reinforced phase nickel-based wear-resistant coating according to claim 1, characterized in that, The chemical composition of the TC4 titanium alloy matrix, in mass percentage, includes: Al 5.5%-6.75%, V 3.5%-4.5%, Fe≤0.30%, O≤0.20%, C≤0.08%, N≤0.05%, H≤0.015%, Si≤0.1%, balance Ti.

5. The method for preparing a multi-component reinforced phase nickel-based wear-resistant coating according to claim 1, characterized in that, The pretreatment process of the TC4 titanium alloy substrate is as follows: first, the surface of the TC4 titanium alloy substrate is mechanically polished with 60-grit sandpaper to remove surface oxides and impurities. Then, anhydrous ethanol is used for cleaning to remove residual debris on the surface. Finally, the substrate is placed in an ultrasonic cleaner and ultrasonically cleaned with acetone for 5 minutes.

6. The method for preparing a multi-component reinforced phase nickel-based wear-resistant coating according to claim 1, characterized in that, The composite cladding powder is dried before use at a temperature of 90℃-150℃ for a time of 90min-120min.

7. The method for preparing a multi-component reinforced phase nickel-based wear-resistant coating according to claim 1, characterized in that, The laser power of the laser cladding is 800W-1200W, the scanning speed is 360mm / min-480mm / min, the powder feeding rate is 20g / min-22g / min, the spot diameter is 4.1mm-4.2mm, and the flow rate of the protective gas is 8L / min-10L / min. If the scanning speed is lower than 360mm / min, the heat input will be too high, and a large amount of WC will decompose, resulting in excessive W2C and embrittlement of the coating. If the scanning speed is higher than 480mm / min, the powder will not melt completely, resulting in pore defects.

8. A multi-component reinforced phase nickel-based wear-resistant coating, prepared by the method for preparing a multi-component reinforced phase nickel-based wear-resistant coating according to any one of claims 1-7, characterized in that, The multi-component reinforced nickel-based wear-resistant coating is applied to the surface of the TC4 titanium alloy substrate and undergoes element interdiffusion at the interface with the TC4 titanium alloy substrate to form a continuous and dense metallurgical bonding layer.

9. The multi-component reinforced phase nickel-based wear-resistant coating according to claim 8, characterized in that, The multi-component reinforced phase nickel-based wear-resistant coating simultaneously meets the following conditions: A. The thickness of the multi-component reinforced nickel-based wear-resistant coating is 1.25mm-2mm; B. The microstructure of the multi-component reinforced nickel-based wear-resistant coating includes cellular crystals, dendritic crystals, and reinforcing phases distributed in the grain boundaries and intergranular regions; C. The phase composition of the multi-component reinforced nickel-based wear-resistant coating includes: TiN, TiC, α-Ti, W2C, Cr7C3, Ti(C,N), Ni3Ti, and (W,Ti)C. 1-x .

10. An application of a multi-component reinforced phase nickel-based wear-resistant coating, characterized in that, The coating is applied to a titanium alloy product, wherein the wear-resistant coating is applied to the surface of a TC4 titanium alloy component for manufacturing titanium alloy parts that are subjected to heavy loads and high-temperature alternating friction conditions for a long time.

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