Multi-element alloy coatings, their toughening design methods and preparation methods

Abstract

This invention provides a multi-element alloy coating, its toughening design method, and its preparation method. The design method includes: screening a multi-element alloy system and rare-earth strengthening elements; screening target composition ranges with high toughening potential; forming a substrate coating using high-throughput magnetron sputtering; selecting a target substrate composition with a single disordered solid solution phase; co-sputtering with rare-earth strengthening elements to form a phase transformation-controlled coating; performing structural characterization and performance testing; and selecting a coating composition and element content with an ordered phase formed by the transformation of a single disordered solid solution phase under rare-earth-induced conditions, and whose coating performance meets the design objectives, as the design output. This invention, for the first time, combines the technological advantages of magnetron sputtering with the phase transformation-inducing function of rare-earth elements, achieving ordered toughening of the coating under relatively low-temperature conditions, providing a new approach for the development of high-performance coatings.

Description

Technical Field

[0001] This invention belongs to the field of material surface protection and coating design technology, specifically relating to a multi-element alloy coating, its toughening design method and preparation method. Background Technology

[0002] As industrial applications place increasingly higher demands on the performance of alloy materials, the rate of performance degradation accelerates under extreme operating conditions, with damage forms such as high-temperature deformation and fatigue cracking, oxidation spalling, wear, and corrosion becoming increasingly severe. To overcome the performance limits of substrates, surface coating technology constructs a film with specific functionalities and protective properties on the surface of the substrate material through physical / chemical methods. This combination of "specific functional coating + substrate" offers high design flexibility, a wide range of technology and material choices, and is cost-effective, effectively improving the service life of the substrate and extending the durability of in-service components.

[0003] Multi-element alloy coatings are currently one of the most widely used and effective methods to rapidly extend the service life of components. However, traditional functional multi-element alloy coatings still suffer from insufficient mechanical properties under complex service environments. For example, they exhibit low bonding strength with the substrate, poor toughness, and insufficient thermal shock resistance, leading to premature peeling and failure, thus hindering their ability to perform their specific functions. Furthermore, the mechanical properties of a coating depend entirely on its surface integrity, microstructure, stress state, composition, and interface structure. Existing coating preparation processes often result in significant performance differences, making it difficult to quickly and accurately control the coating's microstructure and limiting the optimization of its mechanical properties.

[0004] To enhance the long-term service capability of multi-element alloy coatings under extreme environments, traditional strengthening methods (such as solid solution strengthening and second-phase strengthening) often improve strength by suppressing dislocation movement, but this significantly sacrifices the material's ductility and toughness. This leads to the coating being prone to crack initiation and rapid propagation under conditions such as thermal shock and mechanical impact, ultimately resulting in premature failure. Disorder-order transformation strengthening, as a potential strengthening mechanism, has not been fully studied in the application of multi-element alloy coatings. This mechanism, by regulating the degree of order in the atomic arrangement of the alloy, can form ordered domain structures at the nanoscale, which can both hinder dislocation movement (improving strength) and coordinate plastic deformation through ordered domain boundaries (improving toughness). However, achieving an ordered phase transformation in bulk materials usually requires prolonged high-temperature heat treatment, a process that easily leads to coating grain coarsening, increased thermal stress, and even cracking, making it incompatible with coating preparation techniques.

[0005] Therefore, the inventors of this invention believe that developing a multi-element alloy coating design method based on coating preparation processes such as magnetron sputtering, using rare earth elements to precisely induce disorder-order phase transitions and strengthen disorder-order phase transitions, and constructing a "high strength-high toughness" synergistic coating structure at the nanoscale through in-situ regulation during the deposition process has become a key path to break through the bottlenecks of existing technologies. Summary of the Invention

[0006] The main objective of this invention is to provide a multi-element alloy coating, its toughening design method, and its preparation method to overcome the shortcomings of the prior art.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for strengthening and toughening a multi-element alloy coating by in-situ formation of nano-ordered domains induced by rare earth elements, comprising:

[0009] Screening matrix multi-element alloy systems and rare earth strengthening elements with target properties, wherein the rare earth strengthening elements serve as phase transformation modulators for the matrix multi-element alloy system;

[0010] Based on thermodynamic calculations and phase diagram predictions, target composition ranges with high strength and toughness potential were screened.

[0011] Within the target composition range, a matrix coating of the matrix multi-element alloy system with continuously varying composition is formed using a high-throughput magnetron sputtering method.

[0012] In the substrate coating, a target matrix component having a single disordered solid solution phase is selected;

[0013] The target matrix component and the rare earth reinforcing element are co-sputtered to form a phase change controlled coating.

[0014] The phase change controlled coating was characterized and its performance was tested. The coating composition and element content that formed an ordered phase from the single disordered solid solution phase under rare earth induction and whose coating performance met the design target were selected as the design output.

[0015] Secondly, the present invention also provides a method for preparing a multi-element alloy coating in which rare earth elements induce in-situ formation of nano-ordered domains, comprising:

[0016] The design output was obtained by using the above-mentioned multi-element alloy coating toughening design method;

[0017] Based on the design output, the target matrix composition and rare earth strengthening elements are selected for co-sputtering to form a multi-element alloy coating in which rare earth elements induce in-situ formation of nano-ordered domains.

[0018] Thirdly, the present invention also provides a multi-element alloy coating prepared by the above preparation method, wherein the multi-element alloy coating has an ordered phase, which is formed by rare earth element-induced transformation of a single disordered solid solution phase composed of the target matrix composition.

[0019] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0020] The design method provided by this invention employs a two-step magnetron sputtering approach. After obtaining the target composition range based on thermodynamic calculations and phase diagram predictions, high-throughput magnetron sputtering is performed using a matrix multi-element alloy system to screen and obtain a base coating with a single, non-solid solution phase. Then, a rare earth-induced coating is formed based on co-sputtering with rare earth elements, and a phase change-controlled coating with a rare earth-induced ordered phase structure and significantly improved coating performance is obtained. This invention is the first to combine the technological advantages of magnetron sputtering with the phase change-inducing function of rare earth elements, achieving ordered and toughened coatings under relatively low temperature conditions, and providing a new approach for the development of high-performance coatings.

[0021] The above description is merely an overview of the technical solution of the present invention. In order to enable those skilled in the art to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described below in conjunction with detailed drawings. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 Isothermal cross-sectional diagram and proposed composition range of a multi-component system at 500℃ are provided as a typical embodiment of the present invention.

[0024] Figure 2 A schematic diagram of high-throughput magnetron sputtering provided as a typical embodiment of the present invention;

[0025] Figure 3a The X-ray diffraction (XRD) pattern of a multi-element alloy coating prepared in a typical embodiment of the present invention;

[0026] Figure 3b The X-ray diffraction (XRD) pattern of a multi-element alloy coating prepared for another typical embodiment of the present invention;

[0027] Figure 4aElectron micrograph of the surface morphology of a multi-element alloy coating prepared in a typical embodiment of the present invention;

[0028] Figure 4b Electron micrograph of the cross-sectional morphology of a multi-element alloy coating prepared in a typical embodiment of the present invention;

[0029] Figure 5a Electron micrograph of the surface morphology of a multi-element alloy coating prepared for another typical embodiment of the present invention;

[0030] Figure 5b Electron micrograph of the cross-sectional morphology of a multi-element alloy coating prepared for another typical embodiment of the present invention;

[0031] Figure 6a These are hardness comparison test images of the multi-element alloy coatings prepared in two typical embodiments of the present invention;

[0032] Figure 6b The graph shows a comparison of the elastic modulus of the multi-element alloy coatings prepared in two typical embodiments of the present invention.

[0033] Figure 6c These are comparative test images of the adhesion of multi-element alloy coatings prepared in two typical embodiments of the present invention. Detailed Implementation

[0034] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0035] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0036] The inventors of this invention point out that, to enhance the mechanical properties of multi-element alloy coatings and address the problem of rapid coating failure in extreme working conditions, alloy coatings should possess an efficient and flexibly controllable coating composition design method. This method should comprehensively consider the relationship between composition, structure, process, and performance, achieving a design approach that aims to improve performance while using composition-process-structure control as a means. Structure determines performance; the composition and arrangement of materials directly lead to changes in performance. Therefore, determining the structural composition with optimal potential is crucial in the design and application of coating materials, which largely depends on the selection of its composition design, preparation technology, and process parameters. Thus, how to efficiently design the system composition to rapidly control and obtain a coating phase structure with excellent comprehensive mechanical properties, and prepare multi-element coatings with both excellent mechanical properties and thermal stability, is a key issue in optimizing multi-element coating materials.

[0037] Based on the above objectives, this invention first provides a method for strengthening and toughening a multi-element alloy coating by in-situ formation of nano-ordered domains induced by rare earth elements, which includes the following steps:

[0038] Screening matrix multi-element alloy systems and rare earth strengthening elements with target properties, wherein the rare earth strengthening elements serve as phase transformation modulators for the matrix multi-element alloy system;

[0039] Based on thermodynamic calculations and phase diagram predictions, target composition ranges with high strength and toughness potential were screened.

[0040] Within the target composition range, a matrix coating of the matrix multi-element alloy system with continuously varying composition is formed using a high-throughput magnetron sputtering method.

[0041] In the substrate coating, a target matrix component having a single disordered solid solution phase is selected;

[0042] The target matrix component and the rare earth reinforcing element are co-sputtered to form a phase change controlled coating.

[0043] The phase change controlled coating was characterized and its performance was tested. The coating composition and element content that formed an ordered phase from the single disordered solid solution phase under rare earth induction and whose coating performance met the design target were selected as the design output.

[0044] As a typical example, the overall process of the toughening design method provided by this invention is as follows:

[0045] (1) Alloy system design and composition optimization: Select the four or more main alloying elements to construct a multi-element alloy system, with the content of each main element ranging from 1 to 60 at.%; Select one or more of the lanthanide elements and / or Y and Sc, and control their addition amount to 0.1 to 10 at.% as phase transformation regulators to promote the formation of ordered phases.

[0046] (2) Prediction of phase transformation behavior and selection of components: Based on the CALPHAD method, a multi-component thermodynamic database was constructed. The compositional stability range and phase equilibrium boundary of each phase such as FCC, L12, BCC, B2, and L21 were calculated using Pandat software. The relationship between different strengthening metal elements and phase range and phase structure changes was summarized.

[0047] (3) Using multi-target co-sputtering technology, a sample library with varying compositional gradients is prepared on the substrate, wherein: different substrate temperatures are set at 300-750 ℃ ​​to provide phase transition driving force; and the compositional gradient coating is prepared by precisely controlling the power of each target.

[0048] (4) Characterize the composition and phase structure of the prepared coating, focusing on the appearance of ordered superlattice diffraction peaks and the formation of nano-ordered domains, construct the composition-phase change relationship of the coating, and summarize the evolution law of phase structure by metal element type, content and composition.

[0049] (5) In the above-mentioned coating preparation, a component and phase range with excellent comprehensive mechanical properties are selected and prepared. Rare earth elements are added within this component range. The properties of rare earth elements are used to control the transformation of the coating from a single disorder to an ordered structure under the magnetron sputtering process, thereby further enhancing the mechanical properties of the coating.

[0050] (6) The composition, phase and mechanical properties of the prepared coating sample were tested to determine the composition and preparation conditions of a coating sample that enhances the mechanical properties of a multi-element alloy coating.

[0051] In some implementations, the matrix multi-element alloy system includes any one or a combination of two or more of the following: a high-entropy system, a wear-resistant coating system, and a corrosion-resistant coating system.

[0052] In some embodiments, the matrix multi-element alloy system includes any four or more transition metal elements, such as Fe, Ni, Cr, Co, Mo, Ti, Al, etc., and the content of any principal element is 5 to 35 at.%.

[0053] In some embodiments, the rare earth element includes one or more of the lanthanides, Y, and Sc, and is added in an amount of 0.1 to 10 at.%.

[0054] In some implementations, the thermodynamic calculations and phase diagram predictions specifically include the following processes:

[0055] Acquire basic thermodynamic data of binary and ternary systems related to matrix multi-element alloy systems and rare earth strengthening elements;

[0056] The basic thermodynamic data are integrated based on the CALPHAD method;

[0057] Starting with simple binary systems and progressing to complex multi-component systems, multi-component phase diagrams are drawn and compared with known phase diagrams. If they match, the process continues; if they do not match, the process continues to revise until the multi-component phase diagrams are correct, thus obtaining a multi-component thermodynamic database.

[0058] By combining the aforementioned multi-element thermodynamic database and phase diagram calculations, the candidate composition ranges of each phase in the matrix multi-element alloy system and rare earth strengthening elements under different conditions are obtained.

[0059] Based on the phase diagram calculation results, the relationship between phase structure and composition and temperature is obtained. The transformation range of FCC phase → BCC phase → L12 / B2 ordered phase is analyzed. The phase stability is evaluated by combining first principle calculations. The target composition range is obtained from the candidate composition range.

[0060] In some embodiments, the high-throughput magnetron sputtering has a substrate rotation speed of 0, a substrate temperature of 300-750°C, a sputtering power of 10-200 W, and a working gas pressure of 0.8-1.2 Pa.

[0061] In some implementations, the selection of the target matrix composition and the methods for structural characterization and performance testing include the following processes:

[0062] Compositional characterization was performed using energy dispersive spectroscopy (EDS); phase structure characterization was performed using X-ray diffraction (XRD); ordered domain distribution and interface structure characterization were performed using transmission electron microscopy (TEM); hardness and elastic modulus of the samples were measured using nanoindentation; and coating adhesion was evaluated using scratch testing.

[0063] In some implementations, the selection criteria for the design output include:

[0064] Hardness ≥18 GPa, elastic modulus ≥240 GPa, hardness / elastic modulus ≥0.07; X-ray diffraction shows ordered phase content ≥30%, transmission electron microscopy confirms ordered domain size ≤50 nm.

[0065] As some typical examples of the above technical solutions, the implementation steps of the multi-element alloy coating strengthening and toughening design method provided by the present invention may include:

[0066] (1) Alloy system and composition design: Based on the service conditions and expected mechanical properties of the target multi-element alloy, the alloy matrix components are determined and rare earth elements are introduced as phase transformation modifiers to optimize the composition range; multi-element alloy systems and strengthening elements with target properties are screened.

[0067] (2) Thermodynamic calculation and phase diagram prediction: The composition-structure phase diagram of the target system is calculated based on the CALPHAD method to obtain the composition range of different phases, construct the composition-structure evolution relationship, predict the disorder (solid solution) → order (intermetallic compound / short-range order) phase transition trend, and screen the composition range with high strength and toughness potential.

[0068] (3) Rare earth doping and phase transformation induced preparation: Magnetron sputtering technology combined with high-throughput method is used to control different target power ratios and fix the substrate rotation speed at 0 to obtain a multi-element alloy coating with continuously changing composition. The coating composition with a single disordered solid solution phase is screened out. Further co-sputtering of target containing rare earth elements is carried out at a specific substrate temperature (300-750℃) and sputtering power. The process parameter window and the synergistic effect of rare earth elements are used to induce the in-situ generation of nanoscale ordered phases during the coating deposition process.

[0069] (4) Structural characterization and performance testing: The composition, phase composition and microstructure evolution of the coating were analyzed by EDS, XRD and TEM. The presence and intensity of the ordered superlattice diffraction peaks were detected, and the morphology and distribution of the nano-ordered domains were observed. Based on structure and performance, the hardness, elastic modulus and coating adhesion were evaluated by combining nano-indentation and scratch tests.

[0070] (5) Determination of optimal composition and process: Based on the "composition-structure-performance" mapping relationship, the composition and process combination that can induce a significantly ordered phase and has a hardness ≥18 GPa and H / E ≥0.07 through the magnetron sputtering process is selected as the final solution.

[0071] Specifically, in step (1), the multi-element alloy system is a high-entropy system, a wear-resistant coating, or a corrosion-resistant coating system, and its main components are: containing four or more major elements of transition metal elements (such as Fe, Ni, Cr, Co, Mo, Ti, Al, Si, etc.), with the content of each main component ranging from 5 to 35 at.%; the rare earth elements are one or more of lanthanide elements (La, Ce, Pr, Nd, etc.) and / or Y, Sc, with an addition amount of 0.1 to 10 at.%, used to induce disorder-order phase transition and control grain size.

[0072] In step (2), the main steps for establishing the thermodynamic database of the target multi-element alloy system are as follows:

[0073] Step 1: Review the literature to obtain specific thermodynamic data for binary, ternary, and other systems related to the target system;

[0074] Step 2: Integrate the above thermodynamic data based on the CALPHAD method;

[0075] Step 3: Verify accuracy, starting from simple binary systems to complex multi-component systems, draw phase diagrams using Thermo-Calc software and compare them with phase diagrams reported in the literature. If they match, continue; if they do not match, continue to revise until the phase diagrams are correct. Finally, obtain the thermodynamic database of the target multi-component alloy system.

[0076] Step 4: Combine thermodynamic database and phase diagram calculation software Pandat to calculate the phase diagram of the target multi-component alloy system and obtain the composition range of each phase in the multi-component alloy under different conditions;

[0077] Step 5: Based on the phase structure obtained from the phase diagram calculation results, determine the relationship between the phase structure and the changes in composition and temperature, clarify that the phase diagram calculation should focus on analyzing the transformation range of FCC phase → BCC phase → L12 / B2 ordered phase, and combine it with first-principles calculation to evaluate the phase stability.

[0078] The specific process parameter window mentioned in step (3) is: substrate temperature 300-750℃, sputtering power 10~200W, working gas pressure 0.8-1.2 Pa, wherein the rare earth element doping amount is 0.1-10 at.%. The specific steps are as follows:

[0079] Step 1: Obtain pure metal or rare earth targets according to the alloy element types determined in step (2), with a target purity of not less than 99.95%;

[0080] Step 2: Place the single-sided polished 304 stainless steel, monocrystalline silicon or quartz substrate in acetone, ethanol and deionized water respectively for ultrasonic cleaning for ~20 min, and then dry it with nitrogen and fix it on the sample stage.

[0081] Step 3: Shut down the magnetron sputtering vacuum chamber and control the cavity vacuum level to ≤5×10⁻⁶. -7 Torr, set the sputtering working pressure to ~1 Pa, and then introduce ~50 sccm of argon gas with a purity of not less than 99.99%;

[0082] Step 4: Turn on the RF power supply, set the power to ~80 W, and the sputtering time to ~15 min to remove surface oxides through pre-sputtering;

[0083] Step 5: Turn on the substrate heating device for magnetron sputtering. The substrate temperature is 300~750 ℃. After reaching the predetermined temperature, set the target power ratio according to the composition of the designed coating, fix the sample stage rotation speed at 0, open the substrate baffle, and sputter to obtain a multi-element alloy coating.

[0084] In step (4), the composition, structure, and properties of the prepared multi-element alloy coating are characterized. The specific steps are as follows:

[0085] Step 1: Characterize the composition of the prepared sample using EDS (Energy Dispersive Spectrometer);

[0086] Step 2: Characterize the phase structure of the sample by XRD (X-Ray Diffraction), focusing on the evolution of disordered peaks (such as FCC / BCC) to superlattice peaks (such as L12 / B2 / L21);

[0087] Step 3: TEM observation of nanoscale ordered domain distribution and interface structure;

[0088] Step 4: Determine the hardness (H) and elastic modulus (E) of the sample by nanoindentation; evaluate the coating adhesion by scratch test (load 0~50 N).

[0089] This invention also provides a method for preparing a multi-element alloy coating with rare earth element-induced in-situ formation of ordered nanodomains, comprising:

[0090] The design output is obtained by using the multi-element alloy coating toughening design method provided by any of the above embodiments;

[0091] Based on the design output, the target matrix composition and rare earth strengthening elements are selected for co-sputtering to form a multi-element alloy coating in which rare earth elements induce in-situ formation of nano-ordered domains.

[0092] A specific exemplary preparation process can be carried out by using the above-mentioned composition design method to determine the target composition and phase range of the target multi-element alloy coating system, and by designing the target material process parameters in combination with the differences in sputtering yield of different target materials; specifically including the following steps:

[0093] S1, Substrate Etching: Chamber back-bottom vacuum better than 7×10 -7 Torr introduces inert gas into the cavity, maintains the gas flow rate at ~50 sccm, sets the bias voltage range to -480 to -500 V, and performs surface etching on the coating substrate for a set time of 15 min.

[0094] S2. Substrate heating: Turn on the substrate tray heating device for magnetron sputtering. When the substrate temperature reaches the set temperature, set the temperature to 500 ℃ and hold for 20~30 min.

[0095] S3. Transition layer preparation: Inert gas is introduced into the cavity at a flow rate of ~20 sccm, maintaining a vacuum level of 3×10⁻⁶. -3 m Torr, a DC voltage was applied to the NiFe target with a loading power of 200 W, and a transition coating was deposited on the substrate. The deposition time was controlled at 15 min and the substrate rotation speed was controlled at 10 r / min.

[0096] S4. Coating Preparation: Inert gas is introduced into the cavity, and the total gas flow rate is maintained between ~20 sccm, keeping the vacuum degree of the cavity at 3×10⁻⁶.-3 In the m Torr process, a DC voltage is applied to NiFe alloy targets, CrAl alloy targets, Ta targets, Mo targets, and Y targets. The loading power is 40–200 W, the deposition time is controlled at 240 min, and the substrate rotation speed is controlled at 10 r / min. In this step, rare earth element Y is directly incorporated into the growing coating. The energy of the sputtered particles and the substrate temperature are used to provide kinetic conditions for the disorder-order phase transition.

[0097] The present invention also provides that the above-mentioned multi-element alloy coating has an ordered phase, wherein the ordered phase is formed by rare earth element-induced transformation of a single disordered solid solution phase composed of the target matrix composition.

[0098] The technical solution of the present invention will be further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only for illustrating the present invention and do not limit the scope of the present invention.

[0099] Example 1

[0100] This embodiment illustrates the preliminary design stage of the design method for Ni-based rare earth induced toughening coatings based on the above technical solution, as shown below.

[0101] Element selection stage: Based on the differences in the characteristics of elements in the periodic table and in conjunction with literature evaluation, alloy components that meet the following synergistic conditions are selected: body-centered cubic (BCC) structure transition group refractory metal elements with high melting point, high hardness, high temperature strength and excellent thermal stability; at the same time, an appropriate amount of Fe element is added to improve the strength and toughness matching performance of the alloy coating.

[0102] The target model for strengthening was chosen as the Ni-Cr-Al-Y quaternary system, in which Ni is the main element, Cr content is controlled at ~8-10 at%, Al content is maintained at ~15 at%, and Fe content is maintained at ~10 at%.

[0103] The added refractory metal X is a combination of two or more elements selected from groups IVB-VIB, and must simultaneously satisfy the following conditions:

[0104] (i) The difference in atomic radius between the Ni-based system and the Ni-based system is δ∈[9%,12%]

[0105] (ii) Enthalpy of mixing with Ni and Al ΔH∈[-30,-5] kJ / mol

[0106] Phase diagram calculation stage: such as Figure 1As shown, the equilibrium phase diagram of the Ni-Cr-Al-YX system was calculated using the phase diagram calculation software Pandat, where X represents the refractory metal and Fe element to be added. At least the isothermal / variable temperature equilibrium phase diagrams of the system with different contents of X were calculated. The composition variation range of the FCC / BCC / L12 / B2 phases was monitored.

[0107] Component optimization stage: The final components to be prepared are determined through the following steps:

[0108] (i) Summarize the phase range and the pattern of phase change after changes in the types and contents of different elements X.

[0109] (ii) Propose the composition range to be designed and prepared, and control the content of X combination ≤15at%, so as to achieve the preliminary design of the alloy composition of the system.

[0110] Example 2

[0111] This embodiment illustrates the target matrix composition determination stage in the design method of Ni-based rare earth induced toughening coating based on the above technical solution, as shown below.

[0112] 304 stainless steel, silicon wafers, and quartz were selected as substrates. When preparing the NiFe / NiFeCrAlTaMo composite coating on the 304 stainless steel substrate, the NiFe / NiFeCrAlTaMo composite coating was simultaneously prepared on the silicon wafer using the same method. The composite coatings on the silicon wafer and quartz substrate were used for basic characterization of the coating's cross-sectional morphology and phase structure, respectively. Figure 2 As shown, the specific preparation steps for depositing the NiFe / NiFeCrAlTaMo composite coating on the substrate are as follows:

[0113] S1. Single-sided polished 304 stainless steel, silicon wafers, and quartz substrates were sequentially ultrasonically cleaned in acetone, alcohol, and deionized water for 15 min, followed by drying under high-purity nitrogen. The cleaned substrates were then loaded onto a sample tray and placed into a vacuum sample chamber containing a NiFe alloy target (strong magnetic target gun), a CrAl alloy target (DC target gun), and Ta and Mo single targets (prepared by vacuum melting). The vacuum level of the chamber was below 7 × 10⁻⁶. -7 After Torr, argon gas at 50 sccm is introduced to maintain a working pressure of 7 × 10⁻⁶. -3 Connect the Torr to the RF power supply and control the substrate bias voltage at -480~-500 V to etch and clean the substrate for 15 minutes.

[0114] S2. Turn on the substrate heating device and heat the substrate to 500 ℃. After the substrate reaches the predetermined temperature, argon gas is introduced at a flow rate of 20 sccm, maintaining a working pressure of 3×10. -3Torr. The sample tray rotation speed was set to 10 r / min, and the target-substrate distance was set to 90 mm. First, the NiFe target was connected to a DC power supply, with the power set to 200 W and the substrate bias voltage set to -150 V. A NiFe layer was deposited on the substrate surface for 15 min. Keeping the NiFe power constant, the CrAl, Ta, and Mo targets were then connected to DC power supplies, with the power set to 150 W, 50 W, and 40 W respectively. After the parameters were set, the target and substrate baffles were opened, and the sputtering time was 240 min. The sputtering mode was continuous sputtering, and the magnetron sputtering was performed using a PRO Line PVD75 six-target magnetron sputtering coating machine to form a NiFe / NiFeCrAlTaMo composite coating.

[0115] The surface and cross-sectional morphology of the coating were observed using a thermal field emission scanning electron microscope (the back of the silicon wafer was cut with a glass cutter to obtain a flat coating cross-section along the cross-section), and its phase composition was analyzed using an X-ray diffractometer (the coating was grown on a quartz substrate to eliminate interference from the substrate phase), and its composition was characterized using an energy dispersive spectroscopy (EDS) instrument. Figure 3a The X-ray diffraction pattern of the substrate coating prepared in this embodiment is shown. Figure 4a and Figure 4b The images show the surface and cross-sectional morphology of the prepared coating. Testing revealed that the NiFe / NiFeCrAlTaMo composite coating, possessing a single disordered solid solution phase, contained the following Ni contents: 47 at.%, 11.8 at.%, 10.5 at.%, 15.4 at.%, 7.9 at.%, and 7.4 at.%. The total coating thickness was 5.8 μm, with the NiFe coating at 300 nm and the NiFeCrAlTaMo coating at 5.5 μm. Nanoindentation experiments were conducted on six different points on the obtained coating samples. To minimize the influence of surface roughness, undulations, and the substrate, the continuous stiffness method was used, with an indentation depth of 500 nm. The average hardness was 17.37 GPa, the elastic modulus was 242.89 GPa, and the film-substrate adhesion LC2 was 9.2 N. The test results are shown in [Figure number missing]. Figures 6a-6c As shown (combining and comparing the test results in the following examples).

[0116] Example 3

[0117] This embodiment illustrates the rare earth co-sputtering and final confirmation of film information stages in the design method of Ni-based rare earth induced toughening coating based on the above technical solution, as detailed below.

[0118] A NiFe / NiFeCrAlTaMoY composite coating was deposited on a 304 stainless steel substrate. The preparation process was similar to that of the composite coating in Example 1, except that the magnetron sputtering parameters were different. Specifically, the Y target was connected to an RF power supply, the Y target power was set to 40 W, and the power of other target materials was the same as in Example 1. The deposition time was 240 min. After sputtering, the NiFe / NiFeCrAlTaMoY composite coating was obtained.

[0119] The coating prepared in this embodiment was measured using the same testing method as in Example 1. The results showed that the Ni / NiFeCrAlTaMoY composite coating contained 44.9 at.%, 10.5 at.%, 9.6 at.%, 19.3 at.%, 7.2 at.%, and 7.4 at.% Ni at.%, 10.5 at.%, 9.6 at.%, 19.3 at.%, 7.2 at.%, and 7.4 at.% Mo. The total coating thickness was 5.9 μm, with the NiFe coating thickness at 300 nm and the NiFeCrAlTaMoY coating thickness at 5.6 μm. Figure 3b As shown, the coating phase composition is BCC+BCC_L21 phase. Figure 5a and Figure 5b The microstructure of the coating is shown, exhibiting a clear rare-earth-induced ordered phase formation phenomenon; see further... Figures 6a-6c As shown, the coating obtained in this embodiment has a hardness of 20.21 GPa, an elastic modulus of 270.54 GPa, and a film-substrate adhesion LC2 of 16.8 N, which is a significant improvement compared to Example 2.

[0120] Based on the above embodiments, it is clear that the multi-element alloy coating provided by the present invention has excellent mechanical properties, which are achieved through the following two strengthening mechanisms: First, the mechanical properties of the coating are improved through the solid solution strengthening effect of Ta and Mo elements; Second, the rare earth element Y introduced by magnetron sputtering technology further induces the ordered transformation of the coating phase structure from BCC to BCC_L21, which strengthens the coating. The in-situ formed nano-ordered domain structure (size ≤50nm) significantly improves the strength, while also coordinating deformation and improving toughness, thus comprehensively and efficiently improving the overall mechanical properties of the alloy coating.

[0121] Furthermore, the multi-element alloy coating provided by this invention has excellent thermal stability because it forms a single solid solution, and the added Ta and Mo elements are both metal elements with high melting points.

[0122] This invention provides a combined design method for coating materials: phase diagram calculation for elemental composition design, high-throughput experimental screening, specific magnetron sputtering process, and rare earth element regulation of phase structure. This method allows for the simultaneous preparation of multi-component alloy coatings with multiple compositional combinations in a single step. It enables rapid selection of optimal compositional combinations over a wide range of components, significantly simplifying the process and improving the efficiency and accuracy of studying the mechanical properties of multi-component alloy coatings. This invention is the first to combine the advantages of magnetron sputtering with the phase transformation-inducing function of rare earth elements, achieving ordered and toughened coatings under relatively low-temperature conditions, providing a new approach for the development of high-performance coatings.

[0123] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for strengthening and toughening a multi-element alloy coating by in-situ formation of nano-ordered domains induced by rare earth elements, characterized in that, include: Screening matrix multi-element alloy systems and rare earth strengthening elements with target properties, wherein the rare earth strengthening elements serve as phase transformation modulators for the matrix multi-element alloy system; Based on thermodynamic calculations and phase diagram predictions, target composition ranges with high strength and toughness potential were screened. Within the target composition range, a matrix coating of the matrix multi-element alloy system with continuously varying composition is formed using a high-throughput magnetron sputtering method. In the substrate coating, a target matrix component having a single disordered solid solution phase is selected; The target matrix component and the rare earth reinforcing element are co-sputtered to form a phase change controlled coating. The phase change controlled coating was characterized and its performance was tested. The coating composition and element content that formed an ordered phase from the single disordered solid solution phase under rare earth induction and whose coating performance met the design target were selected as the design output.

2. The multi-element alloy coating strengthening and toughening design method according to claim 1, characterized in that, The matrix multi-element alloy system includes any one or a combination of two or more of the following: high-entropy system, wear-resistant coating system, and corrosion-resistant coating system.

3. The multi-element alloy coating strengthening and toughening design method according to claim 2, characterized in that, The matrix multi-element alloy system includes any four or more transition metal elements, and the content of any principal element is 5 to 35 at.

4. The multi-element alloy coating strengthening and toughening design method according to claim 3, characterized in that, The rare earth elements include one or more of the lanthanides, Y, and Sc, and are added in an amount of 0.1~10 at.%.

5. The multi-element alloy coating strengthening and toughening design method according to claim 1, characterized in that, The process of thermodynamic calculation and phase diagram prediction specifically includes: Acquire basic thermodynamic data of binary and ternary systems related to matrix multi-element alloy systems and rare earth strengthening elements; The basic thermodynamic data are integrated based on the CALPHAD method; Starting with simple binary systems and progressing to complex multi-component systems, multi-component phase diagrams are drawn and compared with known phase diagrams. If they match, the process continues; if they do not match, the process continues to revise until the multi-component phase diagrams are correct, thus obtaining a multi-component thermodynamic database. By combining the aforementioned multi-element thermodynamic database and phase diagram calculations, the candidate composition ranges of each phase in the matrix multi-element alloy system and rare earth strengthening elements under different conditions are obtained. Based on the phase diagram calculation results, the relationship between phase structure and composition and temperature is obtained. The transformation range of FCC phase → BCC phase → L12 / B2 ordered phase is analyzed. The phase stability is evaluated by combining first principle calculations. The target composition range is obtained from the candidate composition range.

6. The multi-element alloy coating strengthening and toughening design method according to claim 1, characterized in that, The high-throughput magnetron sputtering has a substrate rotation speed of 0, a substrate temperature of 300-750℃, a sputtering power of 10-200 W, and a working gas pressure of 0.8-1.2 Pa.

7. The multi-element alloy coating strengthening and toughening design method according to claim 1, characterized in that, The selection of the target matrix composition and the methods of structural characterization and performance testing include: Composition was characterized by energy dispersive spectroscopy, phase structure by X-ray diffraction, ordered domain distribution and interface structure by transmission electron microscopy, hardness and elastic modulus of the sample were measured by nanoindentation, and coating adhesion was evaluated by scratch test.

8. The multi-element alloy coating strengthening and toughening design method according to claim 7, characterized in that, The selection criteria for the design output include: Hardness ≥18 GPa, elastic modulus ≥240 GPa, hardness / elastic modulus ≥0.07; X-ray diffraction shows ordered phase content ≥30%, transmission electron microscopy confirms ordered domain size ≤50 nm.

9. A method for preparing a multi-element alloy coating with rare earth element-induced in-situ formation of nano-ordered domains, characterized in that, include: The design output is obtained by using the multi-element alloy coating toughening design method described in any one of claims 1-8; Based on the design output, the target matrix composition and rare earth strengthening elements are selected for co-sputtering to form a multi-element alloy coating in which rare earth elements induce in-situ formation of nano-ordered domains.

10. The multi-element alloy coating prepared by the method of claim 9, characterized in that, The multi-element alloy coating has an ordered phase, which is formed by the transformation of a single disordered solid solution phase composed of the target matrix components through rare earth element-induced transformation.

Images