A method for designing a CrN / Cr multilayer coating modulated by geometric parameter regulation

Abstract

This invention discloses a design method for CrN / Cr multilayer coatings with modulated geometric parameters, including the establishment of a basic geometric parameter library and a material property database. For complex gradient distributions such as constant, increasing / decreasing, V-shaped, and wavy types, this invention automatically generates geometric models by inputting the number of cycles, distribution type, and modulation ratio, avoiding the tedious manual layer-by-layer modeling and achieving efficient preprocessing with "parameters as models." An adaptive meshing strategy is employed, dividing the area near the indentation into multiple elements and setting bias seeds at the interface. Combined with volume-weighted average interpolation of material properties, it accurately captures interlayer stress concentration and gradient transition effects. By automatically traversing different parameter combinations, combined with stress gradient quantification analysis and failure risk assessment, the optimal strengthening structure can be quickly selected, providing data guidance for coating performance control.

Description

Technical Field

[0001] This invention relates to the field of coating parameter control technology, specifically to a design method for CrN / Cr multilayer coatings with modulated geometric parameters. Background Technology

[0002] In modern machining and mold manufacturing, high-performance hard coatings are key technologies for improving tool life and machining accuracy. Chromium nitride (CrN) coatings, with their excellent hardness, good chemical stability, and relatively low deposition temperature, are widely used in cutting tools, mold protection, and decorative coatings. However, the inherent "strong-brittle" contradiction of hard film materials makes them prone to microcracks and brittle peeling failure when faced with extreme and complex conditions such as impact loads, high-frequency friction, and thermal cycling. This toughness bottleneck limits the further application of CrN coatings in high-end fields such as aerospace and precision manufacturing.

[0003] To overcome the brittleness of CrN coatings, a common solution is to introduce a metallic phase with excellent ductility (such as metallic Cr) to construct a CrN / Cr multilayer composite coating system. This system utilizes the synergistic effect between components (i.e., the "toughening" mechanism) and the interfacial effect of the multilayer structure to hinder crack propagation and energy dissipation.

[0004] Previous studies have primarily focused on the effects of constant modulation periods (i.e., a constant thickness ratio of CrN to Cr in each layer) or constant modulation ratios on the macroscopic mechanical properties of coatings (such as hardness and adhesion). For example, by fixing the modulation ratio at 1:1, the influence of different total thicknesses on performance has been studied. However, this single, constant structural design has certain limitations: 1. Uneven stress distribution: In the actual indentation process, the stress field inside the coating is not uniformly distributed with depth. The constant period structure often causes stress to concentrate at a specific interface, making it impossible to achieve stress gradient release.

[0005] 2. Bottleneck in toughness improvement: Although simple periodic stacking can improve toughness to a certain extent, the interlayer interface is still a weak link when facing high-intensity impacts, and is prone to interlayer shear failure. Summary of the Invention

[0006] To address the aforementioned technical problems, a design method for CrN / Cr multilayer coatings with modulated geometric parameters is provided. This technical solution resolves the issues raised in the background section.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect of the invention, a method for designing CrN / Cr multilayer coatings with modulated geometric parameters is provided, comprising: Establish a basic geometric parameter library and a material property database, wherein the basic geometric parameters include the total coating thickness. Matrix thickness The Vickers indenter geometry and indentation depth; the material property database includes the elastic modulus, Poisson's ratio, hardness, initial yield stress, and strain hardening index of the ceramic phase CrN and the metallic phase Cr. Define gradient modulation topology parameters for the multilayer coating, including the number of modulation cycles N, modulation ratio R, and gradient distribution type T; wherein the distribution type T includes constant type Con, increasing type I, decreasing type D, V-shaped symmetrical distributions ID and DI, and wave-shaped distributions IDID and DIDI; Based on the number of modulation cycles N and the modulation ratio R, the single-layer thickness sequence within a single modulation cycle is calculated; for non-constant distributions, a linear or non-linear functional relationship between the layer thickness and the cycle index is established according to the distribution type T, and a list of specific thickness values ​​of the CrN layer and Cr layer within each cycle is generated. Using Python scripts or the built-in script interface of ABAQUS, the generated list of thickness values ​​is read, and each layer of geometric entities is generated sequentially from bottom to top in the three-dimensional spatial coordinate system. Boolean operations are used to merge each layer of entities into a complete coating geometric model, and it is assembled with the 316L stainless steel substrate geometric model to establish a three-dimensional finite element assembly of "indenter-coating-substrate". Mesh generation control is performed on the established assembly model. Structured hexahedral elements are used to sweep the mesh of the coating area, and the element size is automatically adjusted according to the layer thickness to ensure that each single layer contains at least 3 mesh elements. Based on the material property database, the calculated thickness sequence is mapped to material cross-sectional properties, and each layer of the coating model is assigned a corresponding CrN or Cr material parameter to establish a gradient material property field. Set boundary conditions and load conditions, apply full constraints to the bottom of the substrate, apply a vertically downward displacement load to the indenter to simulate nanoindentation test, and define the tangential friction coefficient at the contact surface between the indenter and the coating. Submit a finite element analysis task to extract stress field distribution data inside the coating, especially the peak values ​​of shear stress and normal tensile stress at the interlayer interface, as well as the Von Mises equivalent plastic strain on the coating surface. Based on the extracted stress field data, the maximum principal stress gradient change rate under each gradient distribution type is calculated, and the coating failure risk assessment factor is constructed by combining the modulation cycle number N and the modulation ratio R. The optimal combination of "number of cycles - distribution type - modulation ratio" parameters is selected based on the evaluation factors, and the corresponding geometric model file and stress cloud map data are output.

[0008] Preferably, the calculation of the single-layer thickness sequence within a single modulation period specifically includes: The theoretical total thickness of a single modulation cycle is set as follows: The calculation formula is: ; in, This represents the theoretical total thickness of a single modulation cycle. Indicates the total coating thickness. Indicates the number of modulation cycles; When the modulation ratio is When the thickness of the CrN layer is defined as The thickness of the Cr layer is ,satisfy and ; The formula for the thickness of a single foundation layer is: ; ; For a constant Con distribution, all periods and Keep the above base values ​​unchanged; For an increasing type I distribution, a thickness growth coefficient is set. , The thickness of the CrN layer in the i-th period is The thickness of the Cr layer is adjusted accordingly to maintain the total thickness of the cycle. It is constant and satisfies 1≤i≤N, where i is the periodic index; For the decreasing D distribution, a linear decreasing algorithm, the opposite of that used for the increasing distribution, is employed. The thickness of the CrN layer in the i-th period is... ; The range of values ​​for α is determined by a preset thickness tolerance constraint to ensure that the minimum single-layer thickness is not less than the minimum size limit of the mesh division.

[0009] Preferably, the generation of thickness sequences for V-shaped symmetrical distributions of ID and DI, and wavy distributions of IDID and DIDI, specifically includes: For the ID type in the V-shaped symmetrical distribution, the modulation period number Divided into the first half and the second half ,and ; First half Each cycle uses an incremental type I thickness calculation formula, the latter half of which... Each cycle uses a decreasing type D thickness calculation formula, and the initial thickness of the second half is equal to the maximum thickness of the first half. For the DI type, the first half uses the calculation formula of the decreasing type D, and the second half uses the calculation formula of the increasing type I. For the wave-shaped distribution IDID, the total number of periods N is divided into 4 equal segments, and the thickness assignment loop of "increment-decrement-increment-decrement" is executed in sequence. The number of periods of each segment is N / 4, and the thickness value at the connection of adjacent segments is continuous. For the DIDI type, perform a "decreasing-increasing-decreasing-increasing" cyclic assignment; When generating the thickness sequence of the above complex distribution, a boundary smoothing process is introduced: at the inflection point of the distribution type, a cubic spline interpolation function is used to fit the thickness abrupt change to generate a continuous thickness transition curve, so as to avoid the appearance of abnormal layers with zero or negative thickness in the geometric modeling.

[0010] Preferably, the step of using a Python script or the ABAQUS built-in script interface to read the generated list of thickness values ​​and sequentially generate the geometric entities of each layer from bottom to top in a three-dimensional spatial coordinate system specifically includes: Initialize an empty list of 3D coordinate points. and an empty layer definition table ; Based on the generated thickness sequence, starting from point 0 on the Z-axis, the thickness value of each layer is accumulated sequentially. Calculate the Z-axis coordinate of the top surface of each layer. ; The material type of each layer is CrN or Cr, and the coordinates of the bottom surface are specified. Top surface coordinates And the central XY plane coordinate range is stored. ; Traversal Call the ABAQUS Part.CreatePart or Part.Extrude interface to generate the solid features of each layer by extruding along the positive Z-axis, with the XY plane as the reference plane. When generating each layer of solid, the volume center coordinates and surface area of ​​the solid are recorded for subsequent mesh quality checks. Using the Assembly.Instance command, perform a Boolean union operation (BooleanMerge) on all generated layer entities to form a complete coating component instance; Finally, the coated component instance is translated along the Z-axis to the substrate surface to complete the assembly.

[0011] Preferably, the mesh generation control of the established assembly model specifically includes: Define global grid seed size Furthermore, local mesh refinement is applied to the outermost layer of the coating, with a refinement coefficient of [value missing]. ; For the calculated ultrathin layers, Cr or CrN layers with a thickness of less than 100 nm, it is mandatory to specify at least 2 unit thicknesses, and a structured grid is generated along the layer thickness direction using the mapping grid technique. For regions with drastic gradient changes, such as the apex of a V-shaped distribution or the peaks and troughs of a wave, set an offset seed so that the mesh density is highest at the interface and gradually thins out towards the inner layer. The script embeds a mesh quality check algorithm to calculate the aspect ratio and interior angle deviation of the cells. If distorted cells are detected, the seed distribution is automatically adjusted or the program is switched to a free tetrahedral mesh for fault tolerance, and a warning log is recorded.

[0012] Preferably, the method for establishing the gradient material property field includes spatial interpolation of material parameters: Since there is a certain difference in the elastic modulus between CrN and Cr, a transition unit layer is set at the interlayer interface. For each finite element, calculate its centroid coordinates. , The Z-axis coordinate represents the centroid of the finite element element; according to The interval in which the unit is located determines whether it belongs to a pure CrN layer, a pure Cr layer, or an interface transition region. If the unit is entirely located within a single layer, directly assign the material parameters corresponding to that layer. If an element spans the interface between two materials, the equivalent elastic modulus of the element is calculated using the volume-weighted average method. and equivalent Poisson ratio : ; ; in, This represents the equivalent elastic modulus of the element. Represents the equivalent Poisson's ratio of the element; This indicates the volume occupied by the CrN material within the unit cell. This indicates the volume occupied by Cr material within the unit cell. Indicates the total volume of the unit; This represents the elastic modulus of CrN material. This indicates the elastic modulus of Cr material; This represents the Poisson's ratio of CrN materials. This represents the Poisson's ratio of Cr materials; The calculated equivalent parameters are written into the material property section SectionAssignment to realize the continuous gradient change of material properties with spatial coordinates.

[0013] Preferably, the setting of boundary conditions and load conditions to apply full constraint to the bottom of the base specifically includes: The indenter is defined as an analytical rigid body, and its tip angle is set to 136°, the standard Vickers indenter angle. Create a reference point and couple it with the indenter vertex, then apply the displacement load to that reference point; Set the analysis step to "Static, General" and turn on the large deformation switch; In the load step, a displacement-time curve is defined to make the indenter press into the coating surface at a set depth at a uniform speed within 0.1s, and then hold the load for 0.5s. In the contact property settings, the "indenter-coating" surface contact is defined as surface-to-surface contact, the normal behavior is "hard contact", the tangential behavior is set to penalty function friction, the friction coefficient ranges from 0.1 to 0.3, and it is set as a variable parameter for sensitivity analysis; Fixed constraints are applied to all nodes on the bottom surface of the base, restricting their translational degrees of freedom in three directions and rotational degrees of freedom in three directions.

[0014] Preferably, the calculation of the maximum principal stress gradient change rate under each gradient distribution type based on the extracted stress field data specifically includes: Extract the stress tensor components and equivalent plastic strain from the ODB result file; Multiple paths are defined along the coating depth direction (Z-axis), each path perpendicularly passing through all modulation layers; On each path, with step size Sampling data points, among which Indicates the sampling step size. This represents the minimum thickness among all single layers; Write a Python script to iterate through all sampling points and extract normal stress and interlayer shear stress; Calculate the maximum principal stress gradient change rate within each modulation cycle. ; For wavy and V-shaped distributions, identify stress concentration areas and calculate their proportion in the total thickness; Generate a data table of "depth-stress" distribution curves and calculate the area under the curve as a quantitative indicator of toughness.

[0015] Preferably, it also includes a parameter optimization iterative step based on a traversal algorithm: Establish a parameter scanning matrix, and set the set of values ​​for the modulation period number N as follows: The set of possible values ​​for the modulation ratio R is: The set of values ​​for distribution type T is ; The loop structure calls the steps sequentially to perform fully automatic finite element calculations for each set of parameters in the matrix. Collect the "maximum tensile stress value" and "maximum shear stress value" obtained from each calculation; Construct two-dimensional or three-dimensional data maps, with the horizontal axis representing the number of modulation cycles N and the vertical axis representing the modulation ratio R. Layers / colors represent the distribution type T, and map color levels represent failure risk assessment factors. The minimum point of the evaluation factor is found in the spectrum using a data interpolation algorithm. The parameter combination corresponding to this point is the recommended strong and tough synergistic coating structure. The output includes a report containing the optimal parameter combination. The report format follows the naming convention of "number of cycles-distribution type-modulation ratio", such as "13-ID-3:1".

[0016] Here, the establishment of the parameter scan matrix specifically includes the following steps: (1) Establish the discretized parameter space: Define the first discrete set of modulation period number N as ; Define the second discrete set of modulation ratio R as ,in This represents the thickness ratio of the ceramic phase CrN layer to the metallic phase Cr layer; Define the third discrete set of gradient distribution type T as Where Con represents constant type, I represents increasing type, D represents decreasing type, ID and DI represent V-shaped symmetrical distribution, and IDID and DIDI represent wave-shaped distribution; (2) Construct the three-dimensional parameter scanning matrix: Based on the first discrete set Second discrete set With the third discrete set The parameter scan matrix is ​​generated through Cartesian product operation. Its mathematical expression is: ; The matrix It contains 140 unique parameter combination tuples, each tuple corresponding to a specific coating geometry design scheme.

[0017] In a second aspect of the invention, an electronic device is also provided. The electronic device includes at least one processor; and a memory communicatively connected to the at least one processor; the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of the first aspect of the invention.

[0018] Compared with the prior art, the present invention provides a design method for CrN / Cr multilayer coatings with modulated geometric parameters, which has the following advantages: This invention targets complex gradient distributions such as constant, increasing / decreasing, V-shaped, and wave-shaped gradients. By inputting the number of cycles, distribution type, and modulation ratio, it can automatically generate a geometric model, avoiding the tedious manual layer-by-layer modeling and achieving efficient preprocessing with "parameters as models." It employs an adaptive meshing strategy, dividing the area near the indentation into multiple elements and setting bias seeds at the interface. Combined with volume-weighted average interpolation of material properties, it accurately captures interlayer stress concentration and gradient transition effects. By automatically traversing different parameter combinations and combining stress gradient quantification analysis and failure risk assessment, it can quickly screen out the optimal strengthening and toughening structure, providing data guidance for coating performance control. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the method flow of S101-S110 in this invention; Figure 2 This is a schematic diagram of the method flow for S201-S206 in this invention; Figure 3 This is a schematic diagram of the method flow for S301-S306 in this invention. Detailed Implementation

[0020] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0021] Example 1 Please refer to Figure 1 As shown, in a first aspect of the present invention, a method for designing CrN / Cr multilayer coatings with modulated geometric parameters is provided, comprising: S101. Establish a basic geometric parameter library and a material property database. The basic geometric parameters include the total coating thickness. Matrix thickness Vickers indenter geometry and indentation depth; material property database includes elastic modulus, Poisson's ratio, hardness, initial yield stress, and strain hardening index of ceramic phase CrN and metallic phase Cr; S102. Define the gradient modulation topology parameters of the multilayer coating. The parameters include the number of modulation cycles N, the modulation ratio R, and the gradient distribution type T. The distribution type T includes constant type Con, increasing type I, decreasing type D, V-shaped symmetrical distribution ID and DI, and wave-shaped distribution IDID and DIDI. S103. Based on the number of modulation cycles N and the modulation ratio R, calculate the single-layer thickness sequence within a single modulation cycle; for non-constant distributions, establish a linear or non-linear functional relationship between the layer thickness and the cycle index according to the distribution type T, and generate a list of specific thickness values ​​for the CrN layer and the Cr layer within each cycle. S104. Using Python scripts or the built-in script interface of ABAQUS, read the generated list of thickness values ​​and generate the geometric entities of each layer from bottom to top in the three-dimensional coordinate system. Merge the entities of each layer into a complete coating geometric model through Boolean operations, and assemble it with the geometric model of 316L stainless steel substrate to establish a three-dimensional finite element assembly of "indenter-coating-substrate". S105. Mesh generation control is performed on the established assembly model. Structured hexahedral elements are used to sweep the mesh generation of the coating area, and the element size is automatically adjusted according to the layer thickness variation to ensure that each single layer contains at least 3 layers of mesh elements. S106. Based on the material property database, map the calculated thickness sequence to material cross-sectional properties, assign corresponding CrN or Cr material parameters to each layer of the coating model, and establish a gradient material property field. S107. Set boundary conditions and load conditions, apply full constraints to the bottom of the substrate, apply a vertically downward displacement load to the indenter to simulate nanoindentation test, and define the tangential friction coefficient at the contact surface between the indenter and the coating. S108. Submit a finite element calculation task to extract stress field distribution data inside the coating, especially the peak values ​​of shear stress and normal tensile stress at the interlayer interface, as well as the Von Mises equivalent plastic strain on the coating surface. S109. Based on the extracted stress field data, calculate the maximum principal stress gradient change rate under each gradient distribution type, and combine the modulation cycle number N and modulation ratio R to construct a coating failure risk assessment factor. S110. Select the optimal combination of "number of cycles - distribution type - modulation ratio" parameters based on the evaluation factors, and output the corresponding geometric model file and stress cloud map data.

[0022] Those skilled in the art will understand that this invention, for complex gradient distributions such as constant, increasing / decreasing, V-shaped, and wave-shaped gradients, can automatically generate geometric models by inputting the number of cycles, distribution type, and modulation ratio, avoiding the tediousness and errors of manual layer-by-layer modeling and achieving efficient preprocessing of "parameters as models." It employs an adaptive meshing strategy, forcibly dividing extremely thin layers into multiple units and setting bias seeds at the interfaces. Combined with volume-weighted average interpolation of material properties, it accurately captures interlayer stress concentration and gradient transition effects, truly reflecting the mechanical response of the coating. By automatically traversing different parameter combinations, combined with stress gradient quantification analysis and failure risk assessment, it can quickly screen out the optimal strengthening and toughening structure, providing precise data guidance for coating performance control.

[0023] Calculating the single-layer thickness sequence within a single modulation period specifically includes: The theoretical total thickness of a single modulation cycle is set as follows: The calculation formula is: ; in, This represents the theoretical total thickness of a single modulation cycle. Indicates the total coating thickness. Indicates the number of modulation cycles; When the modulation ratio is When the thickness of the CrN layer is defined as The thickness of the Cr layer is ,satisfy and ; The formula for the thickness of a single foundation layer is: ; ; For a constant Con distribution, all periods and Keep the above base values ​​unchanged; For an increasing type I distribution, a thickness growth coefficient is set. , The thickness of the CrN layer in the i-th period is The thickness of the Cr layer is adjusted accordingly to maintain the total thickness of the cycle. It is constant and satisfies 1≤i≤N, where i is the periodic index; For the decreasing D distribution, a linear decreasing algorithm, the opposite of that used for the increasing distribution, is employed. The thickness of the CrN layer in the i-th period is... ; The range of values ​​for α is determined by a preset thickness tolerance constraint to ensure that the minimum single-layer thickness is not less than the minimum size limit of the mesh division.

[0024] Please refer to Figure 2 As shown, the generation of thickness sequences for V-shaped symmetrical distributions of ID and DI, and wavy distributions of IDID and DIDI, specifically includes: S201. For the ID type in the V-shaped symmetrical distribution, the modulation period number... Divided into the first half and the second half ,and ; S202, First Half Each cycle uses an incremental type I thickness calculation formula, the latter half of which... Each cycle uses a decreasing type D thickness calculation formula, and the initial thickness of the second half is equal to the maximum thickness of the first half. S203. For the DI type, the first half uses the calculation formula of the decreasing type D, and the second half uses the calculation formula of the increasing type I. S204. For the wave-shaped distribution IDID, the total number of periods N is divided into 4 equal segments, and the thickness assignment loop of "increment-decrement-increment-decrement" is executed in sequence. The number of periods of each segment is N / 4, and the thickness value at the connection of adjacent segments is continuous. S205. For the DIDI type, perform a "decreasing-increasing-decreasing-increasing" cyclic assignment; S206. When generating the thickness sequence of the above complex distribution, a boundary smoothing process is introduced: at the inflection point of the distribution type, a cubic spline interpolation function is used to fit the thickness change to generate a continuous thickness transition curve, so as to avoid abnormal layers with zero or negative thickness in the geometric modeling.

[0025] Using Python scripts or the ABAQUS built-in script interface, the generated list of thickness values ​​is read, and the geometric entities of each layer are generated sequentially from bottom to top in a three-dimensional coordinate system, specifically including: Initialize an empty list of 3D coordinate points. and an empty layer definition table ; Based on the generated thickness sequence, starting from point 0 on the Z-axis, the thickness value of each layer is accumulated sequentially. Calculate the Z-axis coordinate of the top surface of each layer. ; The material type of each layer is CrN or Cr, and the coordinates of the bottom surface are specified. Top surface coordinates And the central XY plane coordinate range is stored. ; Traversal Call the ABAQUS Part.CreatePart or Part.Extrude interface to generate the solid features of each layer by extruding along the positive Z-axis, with the XY plane as the reference plane. When generating each layer of solid, the volume center coordinates and surface area of ​​the solid are recorded for subsequent mesh quality checks. Using the Assembly.Instance command, perform a Boolean union operation (BooleanMerge) on all generated layer entities to form a complete coating component instance; Finally, the coated component instance is translated along the Z-axis to the substrate surface to complete the assembly.

[0026] Mesh generation control is performed on the established assembly model, specifically including: Define global grid seed size Furthermore, local mesh refinement is applied to the outermost layer of the coating, with a refinement coefficient of [value missing]. ; For the calculated ultrathin layers, Cr or CrN layers with a thickness of less than 100 nm, it is mandatory to specify at least 2 unit thicknesses, and a structured grid is generated along the layer thickness direction using the mapping grid technique. For regions with drastic gradient changes, such as the apex of a V-shaped distribution or the peaks and troughs of a wave, set an offset seed so that the mesh density is highest at the interface and gradually thins out towards the inner layer. The script embeds a mesh quality check algorithm to calculate the aspect ratio and interior angle deviation of the cells. If distorted cells are detected, the seed distribution is automatically adjusted or the program is switched to a free tetrahedral mesh for fault tolerance, and a warning log is recorded.

[0027] Methods for establishing gradient material property fields include spatial interpolation of material parameters: Since there is a certain difference in the elastic modulus between CrN and Cr, a transition unit layer is set at the interlayer interface. For each finite element, calculate its centroid coordinates. , The Z-axis coordinate represents the centroid of the finite element element; according to The interval in which the unit is located determines whether it belongs to a pure CrN layer, a pure Cr layer, or an interface transition region. If the unit is entirely located within a single layer, directly assign the material parameters corresponding to that layer. If an element spans the interface between two materials, the equivalent elastic modulus of the element is calculated using the volume-weighted average method. and equivalent Poisson ratio : ; ; in, This represents the equivalent elastic modulus of the element. Represents the equivalent Poisson's ratio of the element; This indicates the volume occupied by the CrN material within the unit cell. This indicates the volume occupied by Cr material within the unit cell. Indicates the total volume of the unit; This represents the elastic modulus of CrN material. This indicates the elastic modulus of Cr material; This represents the Poisson's ratio of CrN materials. This represents the Poisson's ratio of Cr materials; The calculated equivalent parameters are written into the material property section SectionAssignment to realize the continuous gradient change of material properties with spatial coordinates.

[0028] Please refer to Figure 3 As shown, boundary conditions and load cases are set to apply full constraints to the bottom of the base, specifically including: S301. Define the indenter as an analytical rigid body, and set its tip angle to 136° standard Vickers indenter angle. S302. Create a reference point and couple it with the indenter vertex, and apply the displacement load to the reference point; S303, Set the analysis step to "Static, General", and turn on the large deformation switch; S304. In the load step, define a displacement-time curve so that the indenter is pressed into the coating surface at a set depth at a uniform speed within 0.1s, and then the load is maintained for 0.5s. S305. In the contact property settings, define the "indenter-coating" surface contact as surface-to-surface contact, the normal behavior as "hard contact", the tangential behavior as penalty function friction, the friction coefficient range as 0.1~0.3, and set it as a variable parameter for sensitivity analysis. S306. Apply fixed constraints to all nodes on the bottom surface of the base, restricting their translational degrees of freedom in three directions and rotational degrees of freedom in three directions.

[0029] Based on the extracted stress field data, the maximum principal stress gradient change rate is calculated for each gradient distribution type, specifically including: Extract the stress tensor components and equivalent plastic strain from the ODB result file; Multiple paths are defined along the coating depth direction (Z-axis), each path perpendicularly passing through all modulation layers; On each path, with step size Sampling data points, among which Indicates the sampling step size. This represents the minimum thickness among all single layers; Write a Python script to iterate through all sampling points and extract normal stress and interlayer shear stress; Calculate the maximum principal stress gradient change rate within each modulation cycle. ; For wavy and V-shaped distributions, identify stress concentration areas and calculate their proportion in the total thickness; Generate a data table of "depth-stress" distribution curves and calculate the area under the curve as a quantitative indicator of toughness.

[0030] It also includes a parameter optimization iterative step based on a traversal algorithm: Establish a parameter scanning matrix, and set the set of values ​​for the modulation period number N as follows: The set of possible values ​​for the modulation ratio R is: The set of values ​​for distribution type T is ; The loop structure calls the steps sequentially to perform fully automatic finite element calculations for each set of parameters in the matrix. Collect the "maximum tensile stress value" and "maximum shear stress value" obtained from each calculation; Construct two-dimensional or three-dimensional data maps, with the horizontal axis representing the number of modulation cycles N and the vertical axis representing the modulation ratio R. Layers / colors represent the distribution type T, and map color levels represent failure risk assessment factors. The minimum point of the evaluation factor is found in the spectrum using a data interpolation algorithm. The parameter combination corresponding to this point is the recommended strong and tough synergistic coating structure. The output includes a report containing the optimal parameter combination. The report format follows the naming convention of "number of cycles-distribution type-modulation ratio", such as "13-ID-3:1".

[0031] In a second aspect of the invention, an electronic device is also provided. The electronic device includes at least one processor; and a memory communicatively connected to the at least one processor; the memory stores instructions executable by the at least one processor, which, when executed by the at least one processor, enable the at least one processor to perform the method of the first aspect of the invention.

[0032] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A method for designing CrN / Cr multilayer coatings with modulated geometric parameters, characterized in that, include: Establish a basic geometric parameter library and a material property database, wherein the basic geometric parameters include the total coating thickness. Matrix thickness The Vickers indenter geometry and indentation depth; the material property database includes the elastic modulus, Poisson's ratio, hardness, initial yield stress, and strain hardening index of the ceramic phase CrN and the metallic phase Cr. Define gradient modulation topology parameters for the multilayer coating, including the number of modulation cycles N, modulation ratio R, and gradient distribution type T; wherein the distribution type T includes constant type Con, increasing type I, decreasing type D, V-shaped symmetrical distributions ID and DI, and wave-shaped distributions IDID and DIDI; Based on the number of modulation cycles N and the modulation ratio R, the single-layer thickness sequence within a single modulation cycle is calculated; for non-constant distributions, a linear or non-linear functional relationship between the layer thickness and the cycle index is established according to the distribution type T, and a list of specific thickness values ​​of the CrN layer and Cr layer within each cycle is generated. Using Python scripts or the built-in script interface of ABAQUS, the generated list of thickness values ​​is read, and the geometric entities of each layer are generated sequentially from bottom to top in the three-dimensional coordinate system. The entities of each layer are merged into a complete coating geometric model through Boolean operations, and then assembled with the geometric model of 316L stainless steel substrate to establish a three-dimensional finite element assembly of "indenter-coating-substrate". Mesh generation control is performed on the established assembly model. Structured hexahedral elements are used to sweep the mesh of the coating area, and the element size is automatically adjusted according to the layer thickness to ensure that each single layer contains at least 3 mesh elements. Based on the material property database, the calculated thickness sequence is mapped to material cross-sectional properties, and each layer of the coating model is assigned a corresponding CrN or Cr material parameter to establish a gradient material property field. Set boundary conditions and load conditions, apply full constraints to the bottom of the substrate, apply a vertically downward displacement load to the indenter to simulate nanoindentation test, and define the tangential friction coefficient at the contact surface between the indenter and the coating. Submit a finite element analysis task to extract stress field distribution data inside the coating, especially the peak values ​​of shear stress and normal tensile stress at the interlayer interface, as well as the Von Mises equivalent plastic strain on the coating surface. Based on the extracted stress field data, the maximum principal stress gradient change rate under each gradient distribution type is calculated, and the coating failure risk assessment factor is constructed by combining the modulation cycle number N and the modulation ratio R. The optimal combination of "number of cycles - distribution type - modulation ratio" parameters is selected based on the evaluation factors, and the corresponding geometric model file and stress cloud map data are output.

2. The design method for CrN / Cr multilayer coatings with modulated geometric parameters according to claim 1, characterized in that, The calculation of the single-layer thickness sequence within a single modulation period specifically includes: The theoretical total thickness of a single modulation cycle is set as follows: The calculation formula is: ； in, This represents the theoretical total thickness of a single modulation cycle. Indicates the total coating thickness. Indicates the number of modulation cycles; When the modulation ratio is When the thickness of the CrN layer is defined as The thickness of the Cr layer is ,satisfy and ; The formula for the thickness of a single foundation layer is: ； ； For a constant Con distribution, all periods and Keep the above base values ​​unchanged; For an increasing type I distribution, a thickness growth coefficient is set. , The thickness of the CrN layer in the i-th period is The thickness of the Cr layer is adjusted accordingly to maintain the total thickness of the cycle. It is constant and satisfies 1≤i≤N, where i is the periodic index; For the decreasing D distribution, a linear decreasing algorithm, the opposite of that used for the increasing distribution, is employed. The thickness of the CrN layer in the i-th period is... ; The range of values ​​for α is determined by a preset thickness tolerance constraint to ensure that the minimum single-layer thickness is not less than the minimum size limit of the mesh division.

3. The design method for CrN / Cr multilayer coatings with modulated geometric parameters according to claim 2, characterized in that, The generation of thickness sequences for V-shaped symmetrical distributions of ID and DI, and wavy distributions of IDID and DIDI, specifically includes: For the ID type in the V-shaped symmetrical distribution, the modulation period number Divided into the first half and the second half ,and ; First half Each cycle uses an incremental type I thickness calculation formula, the latter half of which... Each cycle uses a decreasing type D thickness calculation formula, and the initial thickness of the second half is equal to the maximum thickness of the first half. For the DI type, the first half uses the calculation formula of the decreasing type D, and the second half uses the calculation formula of the increasing type I. For the wave-shaped distribution IDID, the total number of periods N is divided into 4 equal segments, and the thickness assignment loop of "increment-decrement-increment-decrement" is executed in sequence. The number of periods of each segment is N / 4, and the thickness value at the connection of adjacent segments is continuous. For the DIDI type, perform a "decreasing-increasing-decreasing-increasing" cyclic assignment; When generating the thickness sequence of the above complex distribution, a boundary smoothing process is introduced: at the inflection point of the distribution type, a cubic spline interpolation function is used to fit the thickness abrupt change to generate a continuous thickness transition curve, so as to avoid the appearance of abnormal layers with zero or negative thickness in the geometric modeling.

4. The design method for CrN / Cr multilayer coatings with modulated geometric parameters according to claim 3, characterized in that, The process involves using Python scripts or the ABAQUS built-in script interface to read the generated list of thickness values ​​and sequentially generating geometric entities for each layer from bottom to top in a three-dimensional coordinate system. Specifically, this includes: Initialize an empty list of 3D coordinate points. and an empty layer definition table ; Based on the generated thickness sequence, starting from point 0 on the Z-axis, the thickness value of each layer is accumulated sequentially. Calculate the Z-axis coordinate of the top surface of each layer. ; The material type of each layer is CrN or Cr, and the coordinates of the bottom surface are specified. Top surface coordinates And the central XY plane coordinate range is stored. ; Traversal Call the ABAQUS Part.CreatePart or Part.Extrude interface to generate the solid features of each layer by extruding along the positive Z-axis with the XY plane as the reference plane. When generating each layer of solid, the volume center coordinates and surface area of ​​the solid are recorded for subsequent mesh quality checks. Using the Assembly.Instance command, perform a Boolean union operation (BooleanMerge) on all generated layer entities to form a complete coating component instance; Finally, the coated component instance is translated along the Z-axis to the substrate surface to complete the assembly.

5. The design method for CrN / Cr multilayer coatings with modulated geometric parameters according to claim 4, characterized in that, The mesh generation control of the established assembly model specifically includes: Define global grid seed size Furthermore, local mesh refinement is applied to the outermost layer of the coating, with a refinement coefficient of [value missing]. ; For the calculated ultrathin layers, Cr or CrN layers with a thickness of less than 100 nm, it is mandatory to specify at least 2 unit thicknesses, and a structured grid is generated along the layer thickness direction using the mapping grid technique. For regions with drastic gradient changes, such as the apex of a V-shaped distribution or the peaks and troughs of a wave, set an offset seed so that the mesh density is highest at the interface and gradually thins out towards the inner layer. The script embeds a mesh quality check algorithm to calculate the aspect ratio and interior angle deviation of the cells. If distorted cells are detected, the seed distribution is automatically adjusted or the program is switched to a free tetrahedral mesh for fault tolerance, and a warning log is recorded.

6. The design method for CrN / Cr multilayer coatings with modulated geometric parameters according to claim 5, characterized in that, The method for establishing a gradient material property field includes spatial interpolation of material parameters: Since there is a certain difference in the elastic modulus between CrN and Cr, a transition unit layer is set at the interlayer interface. For each finite element, calculate its centroid coordinates. , The Z-axis coordinate represents the centroid of the finite element element; according to The interval in which the unit is located determines whether it belongs to a pure CrN layer, a pure Cr layer, or an interface transition region. If the unit is entirely located within a single layer, directly assign the material parameters corresponding to that layer. If an element spans the interface between two materials, the equivalent elastic modulus of the element is calculated using the volume-weighted average method. and equivalent Poisson ratio : ； ； in, This represents the equivalent elastic modulus of the element. Represents the equivalent Poisson's ratio of the element; This indicates the volume occupied by the CrN material within the unit cell. This indicates the volume occupied by Cr material within the unit cell. Indicates the total volume of the unit; This represents the elastic modulus of CrN material. This indicates the elastic modulus of Cr material; This represents the Poisson's ratio of CrN materials. This represents the Poisson's ratio of Cr materials; The calculated equivalent parameters are written into the material property section SectionAssignment to realize the continuous gradient change of material properties with spatial coordinates.

7. The design method for CrN / Cr multilayer coatings with modulated geometric parameters according to claim 6, characterized in that, The setting of boundary conditions and load conditions to apply full constraints to the bottom of the base specifically includes: The indenter is defined as an analytical rigid body, and its tip angle is set to 136°, the standard Vickers indenter angle. Create a reference point and couple it with the indenter vertex, then apply the displacement load to that reference point; Set the analysis step to "Static, General" and turn on the large deformation switch; In the load step, a displacement-time curve is defined to make the indenter press into the coating surface at a set depth at a uniform speed within 0.1s, and then hold the load for 0.5s. In the contact property settings, the "indenter-coating" surface contact is defined as surface-to-surface contact, the normal behavior is "hard contact", the tangential behavior is set to penalty function friction, the friction coefficient ranges from 0.1 to 0.3, and it is set as a variable parameter for sensitivity analysis; Fixed constraints are applied to all nodes on the bottom surface of the base, restricting their translational degrees of freedom in three directions and rotational degrees of freedom in three directions.

8. The design method for CrN / Cr multilayer coatings with modulated geometric parameters according to claim 7, characterized in that, The calculation of the maximum principal stress gradient change rate under each gradient distribution type based on the extracted stress field data specifically includes: Extract the stress tensor components and equivalent plastic strain from the ODB result file; Multiple paths are defined along the coating depth direction (Z-axis), each path perpendicularly passing through all modulation layers; On each path, with step size Sampling data points, among which Indicates the sampling step size. This represents the minimum thickness among all single layers; Write a Python script to iterate through all sampling points and extract normal stress and interlayer shear stress; Calculate the maximum principal stress gradient change rate within each modulation cycle. ; For wavy and V-shaped distributions, identify stress concentration areas and calculate their proportion in the total thickness; Generate a data table of "depth-stress" distribution curves and calculate the area under the curve as a quantitative indicator of toughness.

9. The design method for CrN / Cr multilayer coatings with modulated geometric parameters according to claim 8, characterized in that, It also includes a parameter optimization iterative step based on a traversal algorithm: Establish a parameter scanning matrix, and set the set of values ​​for the modulation period number N as follows: The set of possible values ​​for the modulation ratio R is: The set of values ​​for distribution type T is ; The loop structure calls the steps sequentially to perform fully automatic finite element calculations for each set of parameters in the matrix. Collect the "maximum tensile stress value" and "maximum shear stress value" obtained from each calculation; Construct two-dimensional or three-dimensional data maps, with the horizontal axis representing the number of modulation cycles N and the vertical axis representing the modulation ratio R. Layers / colors represent the distribution type T, and map color levels represent failure risk assessment factors. The minimum point of the evaluation factor is found in the graph using a data interpolation algorithm. The parameter combination corresponding to this point is the recommended strong and tough synergistic coating structure. The output includes a report containing the optimal parameter combination. The report format follows the naming convention of "number of cycles-distribution type-modulation ratio", for example, "13-ID-3:1".

10. An electronic device, comprising at least one processor; and a memory communicatively connected to said at least one processor; characterized in that, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-9.

Images