Research method for multi-scale wear behavior of diamond-coated cutting tools

Abstract

The present invention provides a method for studying the multi-scale wear behavior of diamond-coated cutting tools, which belongs to the technical field of diamond-coated cutting tool wear research. First, in the field of microscopic finite element simulation, a microscopic geometric model is established, and parameters such as material properties and grid size are set for the microscopic geometric model. According to the simulation results, the stress and strain distribution law of the cutting tool is analyzed to obtain the microscopic mechanical wear behavior within the crystals, between the crystals, and between the coating substrates of the polycrystalline coating at the microscale. At the same time, in the field of molecular dynamics, a nanoscopic geometric model is established, reaction potential functions are set, and parameters such as atomic layers and temperature controllers are set. According to the simulation results, the bond formation and breaking between atoms are analyzed to obtain the atomic-level chemical wear behavior of single-crystal diamond at the nanoscale. Finally, the microscopic mechanical wear behavior and the atomic-level chemical wear behavior of single-crystal diamond are combined to obtain the multi-scale wear behavior of the diamond-coated cutting tool.

Description

Technical Field

[0001] The invention belongs to the technical field of diamond coating tool wear research, and particularly relates to a method for studying the multi-scale wear behavior of diamond coating tools. Background Art

[0002] High-end equipment in energy, transportation, and other fields is a concentrated reflection of a country's comprehensive manufacturing strength. Energy, economic, and military competition are forcing the continuous improvement of the performance of such high-end equipment. The use of advanced materials is one of the fundamental ways to improve equipment performance. However, the better the performance of the workpiece material, the worse its machinability. When machining difficult-to-machine materials such as carbon fiber composites, tool wear becomes more severe.

[0003] Diamond-coated cutting tools, with their high hardness and wear resistance, are becoming the preferred choice for machining difficult-to-machine materials such as carbon fiber composites. However, under conditions of high stock removal and high cutting speeds, diamond-coated cutting tools still struggle to meet the demands for continuous, high-quality, and efficient machining of large, high-performance carbon fiber composites and other difficult-to-machine materials. Therefore, understanding the wear behavior of these cutting tools is fundamental to improving their cutting performance.

[0004] The wear behavior of diamond-coated tools during cutting is complex. Currently, the research on the wear behavior of diamond-coated tools mainly focuses on macroscopic experimental observations and is used to obtain the wear locations and surface wear forms such as abrasive wear and fatigue wear. Its disadvantage is that it is impossible to study the tool wear behavior in a deeper level, and only a limited sample interval can be selected to observe the tool wear behavior, resulting in an incomplete description of the tool wear behavior.

[0005] Existing research, including Chinese invention patent number CN202110253578.8, discloses a molecular dynamics-based simulation method for nanoscale diamond friction and wear. This approach uses molecular dynamics to simulate the microstructural changes and stress results of nanoscale diamond during friction and wear, primarily analyzing the effects of temperature changes on the nanoscale diamond wear process. However, existing research lacks analysis of the effects of coating-substrate, intergranular mechanical properties, and interfacial chemical reactions on diamond tool wear behavior, resulting in an incomplete analysis of diamond tool wear behavior. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a multi-scale wear behavior research method for diamond-coated tools, so as to analyze the influence of mechanical properties between coating and substrate, coating grains and chemical reactions between interfaces on tool wear behavior, so as to make the analysis of diamond tool wear behavior more comprehensive.

[0007] The technical solutions adopted by the present invention to solve the technical problems are as follows:

[0008] A method for studying the multi-scale wear behavior of diamond-coated cutting tools comprises the following steps:

[0009] (1) Obtaining the mechanical wear behavior between grains of polycrystalline diamond coating and between coating and substrate at the microscale. The specific steps are as follows:

[0010] S1: Using a finite element simulation method, a micro-geometric model is established, wherein the micro-geometric model includes a diamond coating grain model, a tool substrate model, and a carbon fiber composite material unidirectional plate micro-model;

[0011] S2: Assign material properties to the diamond coating grain model, tool substrate model, and carbon fiber composite unidirectional plate micromodel respectively. Use zero-thickness elements for the diamond coating grain boundaries and the coating-substrate interface, and mesh the above models.

[0012] S3: Assembling the diamond coating grain model and the tool substrate model together to form a diamond coating tool model, and assembling the diamond coating tool model and the carbon fiber composite material unidirectional plate micromodel together in a right-angle cutting manner to form a tool model;

[0013] S4: Set cutting speed parameters for the tool in the tool model, set fixed constraints for the workpiece material, and perform cutting simulation tests; in particular, the carbon fiber three-dimensional linear elastic constitutive algorithm is introduced in combination with the Vumat subroutine to describe the failure of the carbon fiber composite unidirectional plate, and the cohesive unit is used to describe the fracture failure of the diamond coating grains within the grain, between the grains, and between the coating and the substrate;

[0014] S5: Submit the tool model, read the solution result file, analyze the stress and strain distribution of the diamond-coated tool during the cutting process according to the solution result file, and obtain the mechanical wear behavior between the grains of the polycrystalline diamond coating and between the coating and the substrate;

[0015] (2) Obtaining the atomic-level chemical wear behavior of single-crystal diamond at the nanoscale, the specific steps include:

[0016] S1: using molecular dynamics methods to establish a nanoscopic geometric model, wherein the nanoscopic geometric model includes a single crystal diamond hemisphere model and a carbon fiber model;

[0017] S2: Assembling the single crystal diamond hemisphere model and the carbon fiber model, and setting three layers of Newtonian layer, constant temperature layer and boundary layer on the diamond hemisphere and carbon fiber model respectively;

[0018] S3: Select a potential function that can describe the sliding friction system between the single crystal diamond hemisphere model and the carbon fiber model;

[0019] S4: setting molecular dynamics simulation parameters;

[0020] S5: Retrieving the data files and command files of the single crystal diamond hemisphere model and the carbon fiber model to start calculation and generate result files;

[0021] S6: Counting the number of interface bonds between the single crystal diamond hemisphere model and the carbon fiber model and the wear amount of the single crystal diamond hemisphere model according to the result file;

[0022] S7: Use VMD visualization software to open the result file, set it to display only the diamond model, and observe the atomic-level chemical wear behavior of single crystal diamond;

[0023] (3) The multi-scale wear behavior of the diamond coating tool is obtained based on the mechanical wear behavior between the diamond coating grains and between the coating and the substrate and the atomic-level chemical wear behavior of the single-crystal diamond.

[0024] Preferably, in step (1), the process of establishing the diamond coating grain model and the tool substrate model is as follows: first, the code is compiled using the Python language, the required number of grains and substrate size are set, the Voronoi library is called to generate seed points for controlling the size and shape of the grains, and then the code is read using Abaqus, the grain substrate is automatically generated in Abaqus, the corresponding model is established in Abaqus, and then the diamond coating model and the tool substrate model with the grain geometric characteristics are cut out.

[0025] Preferably, in step (1), the process of establishing the microscopic model of the carbon fiber composite material unidirectional plate is as follows: in Abaqus, a microscopic model of the carbon fiber composite material unidirectional plate combined with fibers and resin is established.

[0026] Preferably, in step (2), the process of establishing the nanoscale single crystal diamond hemisphere model is as follows: using Material studio software to establish a nanoscale single crystal diamond cube model, using Matlab to write a program to intercept a single crystal diamond cube model with a radius of The simplified model of the single crystal diamond hemispherical scratching head is obtained to obtain the nanoscale single crystal diamond hemispherical model.

[0027] Preferably, in step (2), the process of establishing the carbon fiber model is as follows: using Material studio software to establish a three-layer long Width The carbon ring basic unit is divided into the carbon ring basic unit with a density of N g / cm 3 Fill in long Width high The carbon fiber model is obtained by minimizing the energy and performing heat treatment on the virtual box, and the length direction of the carbon ring basic unit is distributed at ±10° along the length direction of the box.

[0028] Preferably, in step (2), the potential function is ReaxFF reaction potential function, as shown in formula 1; E system =E bond +E over +E under +E val +E pen +E tors +E conj +E vdWaals +E Coulomb (1); where E system represents the total potential energy of the system, E bond represents the bond energy term, E over represents the over-coordination energy correction term, E under represents the insufficient coordination energy correction term, E val represents the bond angle energy term, E pen represents the valence bond correction term, E tors Torsion angle term, E conj represents the four-body conjugate term, E vdWaals represents the van der Waals interaction term, E Coulomb represents the Coulomb force term.

[0029] Preferably, in step (2), the molecular dynamics simulation parameters include x, y, z three-dimensional boundary conditions, ensemble type, sliding speed, temperature control method, calculation method, and time step.

[0030] Preferably, in step (2), the assembly process of the single crystal diamond hemisphere model and the carbon fiber model is: exporting the single crystal diamond hemisphere model and the carbon fiber model as a coordinate information file, obtaining the coordinate information of each atom in the single crystal diamond hemisphere model and the carbon fiber model from the coordinate information file, and summarizing the coordinate information into a data file to realize the assembly of the single crystal diamond hemisphere model and the carbon fiber model.

[0031] Preferably, in step (2), the statistical method for the number of interface bonds between the single crystal diamond hemisphere model and the carbon fiber model is: using Matlab software to write a data processing program file, extracting the atomic coordinate information of the Newtonian layer of the single crystal diamond hemisphere model and the Newtonian layer of the carbon fiber model in each step of the calculation process in the result file, and allowing each Newtonian layer atom of the single crystal diamond hemisphere model to calculate the spatial distance L with the Newtonian layer atom of the carbon fiber model, as shown in Formula 2, Among them, x d 、y d 、z f They are the x, y, and z coordinates of the atoms in the single crystal diamond hemisphere model, x f 、y f 、z fThey are the x, y, and z coordinates of the atoms in the carbon fiber model respectively; by calculating whether the spatial distance L between diamond and carbon fiber atoms reaches the cutoff radius To determine whether an interface bond is formed between diamond and carbon fiber, and thus obtain the number of interface bonds formed between diamond and carbon fiber in each step;

[0032] The statistical method for calculating the wear amount of the single-crystal diamond hemisphere model comprises: using Matlab software to write a data processing program file, extracting the initial atomic coordinate information of the single-crystal diamond hemisphere model and the atomic coordinate information of each step in the calculation process from the result file, first determining the coordination information of atom m and surrounding atoms in the initial state by using the initial atomic spatial distance L, then calculating the coordination status of each atom in the single-crystal diamond hemisphere model in each step, comparing the coordination information of each atom in the single-crystal diamond hemisphere model in each step with the coordination information of each atom in the initial state, and if a coordination change occurs, it is considered that the diamond atom has been worn, thereby obtaining the amount of diamond atom wear in each step.

[0033] It can be seen from the above technical solution that the present invention provides a method for studying the multi-scale wear behavior of diamond-coated tools. Compared with the existing technology, the present invention has the following beneficial effects: first, in the field of micro-finite element simulation, by establishing a micro-geometric model, setting material properties, grid size and other parameters for the micro-geometric model, and analyzing the stress and strain distribution law of the tool according to the simulation results, so as to obtain the micro-mechanical wear behavior within the polycrystalline coating, between the crystals, and between the coating substrates from the micro scale; at the same time, in the field of molecular dynamics, by establishing a nano-geometric model, setting the reaction potential function, setting the atomic layer, temperature controller and other parameters, and analyzing the bond formation and breaking between atoms according to the simulation results, so as to obtain the atomic-level chemical wear behavior of single-crystal diamond from the nano-scale; finally, combining the micro-mechanical wear behavior and the atomic-level chemical wear behavior of single-crystal diamond, the multi-scale wear behavior of diamond-coated tools is obtained, making the analysis of the wear behavior of diamond tools more comprehensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of mechanical wear behavior between grains of polycrystalline diamond coating and between coating and substrate.

[0035] Figure 2 Schematic diagram of atomic-level chemical wear behavior of a single-crystal diamond hemisphere model. DETAILED DESCRIPTION

[0036] The technical solutions and technical effects of the embodiments of the present invention are further elaborated below in conjunction with the accompanying drawings of the present invention.

[0037] In the present invention, the coordinate information file is a .car file, the result file is a .lammpstrj file, the data file is a .data file, the command file is an in.txt file, and the solution result file is a .odb file. The carbon fiber composite material is a T700 grade carbon fiber composite material.

[0038] The present invention provides a method for studying the multi-scale wear behavior of diamond-coated cutting tools, comprising the following steps:

[0039] (1) Obtaining the mechanical wear behavior between grains of polycrystalline diamond coating and between coating and substrate at the microscale. The specific steps are as follows:

[0040] S1: Using a finite element simulation method, a micro-geometric model is established, wherein the micro-geometric model includes a diamond coating grain model, a tool substrate model, and a carbon fiber composite material unidirectional plate micro-model;

[0041] S2: Assign material properties to the diamond coating grain model, tool substrate model, and carbon fiber composite unidirectional plate micromodel respectively. Use zero-thickness elements for the diamond coating grain boundaries and the coating-substrate interface, and mesh the above models.

[0042] S3: Assembling the diamond coating grain model and the tool substrate model together to form a diamond coating tool model, and assembling the diamond coating tool model and the carbon fiber composite material unidirectional plate micromodel together in a right-angle cutting manner to form a tool model;

[0043] S4: Set cutting speed parameters for the tool in the tool model, set fixed constraints for the workpiece material, and perform cutting simulation tests; in particular, the carbon fiber three-dimensional linear elastic constitutive algorithm is introduced in combination with the Vumat subroutine to describe the failure of the carbon fiber composite unidirectional plate, and the cohesive unit is used to describe the fracture failure of the diamond coating grains within the grain, between the grains, and between the coating and the substrate;

[0044] S5: Submit the tool model, read the solution result file, analyze the stress and strain distribution of the diamond-coated tool during the cutting process according to the solution result file, and obtain the mechanical wear behavior between the grains of the polycrystalline diamond coating and between the coating and the substrate;

[0045] (2) Obtaining the atomic-level chemical wear behavior of single-crystal diamond at the nanoscale, the specific steps include:

[0046] S1: using molecular dynamics methods to establish a nanoscopic geometric model, wherein the nanoscopic geometric model includes a single crystal diamond hemisphere model and a carbon fiber model;

[0047] S2: Assembling the single crystal diamond hemisphere model and the carbon fiber model, and setting three layers of Newtonian layer, constant temperature layer and boundary layer on the diamond hemisphere and carbon fiber model respectively;

[0048] S3: Select a potential function that can describe the sliding friction system between the single crystal diamond hemisphere model and the carbon fiber model;

[0049] S4: setting molecular dynamics simulation parameters;

[0050] S5: Retrieving the data files and command files of the single crystal diamond hemisphere model and the carbon fiber model to start calculation and generate result files;

[0051] S6: Counting the number of interface bonds between the single crystal diamond hemisphere model and the carbon fiber model and the wear amount of the single crystal diamond hemisphere model according to the result file;

[0052] S7: Use VMD visualization software to open the result file, set it to display only the diamond model, and observe the atomic-level chemical wear behavior of single crystal diamond;

[0053] (3) The multi-scale wear behavior of the diamond coating tool is obtained based on the mechanical wear behavior between the diamond coating grains and between the coating and the substrate and the atomic-level chemical wear behavior of the single-crystal diamond.

[0054] The present invention first establishes a microscopic geometric model in the field of microscopic finite element simulation, sets parameters such as material properties and grid size for the microscopic geometric model, and analyzes the stress and strain distribution law of the tool according to the simulation results, so as to obtain the microscopic mechanical wear behavior within the polycrystalline coating, between the crystals, and between the coating substrates from the microscopic scale; at the same time, in the field of molecular dynamics, by establishing a nanoscopic geometric model, setting reaction potential functions, setting parameters such as atomic layers and temperature controllers, and analyzing the bond formation and breaking between atoms according to the simulation results, the atomic-level chemical wear behavior of single-crystal diamond is obtained from the nanoscopic scale; finally, the microscopic mechanical wear behavior and the atomic-level chemical wear behavior of single-crystal diamond are combined to obtain the multi-scale wear behavior of diamond-coated tools, which further improves and enriches the research on the wear behavior of diamond-coated tools.

[0055] Specifically, in step (1), the process of establishing the diamond coating grain model and the tool substrate model is as follows: first, the code is compiled using the Python language, the required number of grains and substrate size are set, the Voronoi library is called to generate seed points for controlling the size and shape of the grains, and then the code is read using Abaqus, the grain substrate is automatically generated in Abaqus, the corresponding model is established in Abaqus, and then the diamond coating model and tool substrate model with the grain geometric characteristics are cut out.

[0056] Specifically, the process of establishing the microscopic model of the carbon fiber composite material unidirectional plate is as follows: in Abaqus, a microscopic model of the carbon fiber composite material unidirectional plate combined with fibers and resin is established.

[0057] Specifically, in step (2), the process of establishing the nanoscale single crystal diamond hemisphere model is as follows: using Material studio software to establish a nanoscale single crystal diamond cube model, using Matlab to write a program to intercept a single crystal diamond cube with a radius of The simplified model of the single crystal diamond hemispherical scratching head is obtained to obtain the nanoscale single crystal diamond hemispherical model.

[0058] Specifically, in step (2), the process of establishing the carbon fiber model is as follows: using Material studio software to establish a three-layer long Width The carbon ring basic unit is divided into the carbon ring basic unit with a density of N g / cm 3 Fill in long Width high The carbon fiber model is obtained by minimizing the energy and performing heat treatment on the virtual box, and the length direction of the carbon ring basic unit is distributed at ±10° along the length direction of the box.

[0059] In order to fully consider the influence of chemical factors such as bond formation and bond breaking on diamond wear, the dangling bonds on the surface of the single crystal diamond hemisphere model were not passivated. In step (2), the potential function used was the ReaxFF reaction potential function, as shown in Formula 1; E system =E bond +E over +E under +E val +E pen +E tors +E conj +E vdWaals +E Coulomb (1); where E system represents the total potential energy of the system, E bond represents the bond energy term, E over represents the over-coordination energy correction term, E under represents the insufficient coordination energy correction term, E val represents the bond angle energy term, E pen represents the valence bond correction term, E tors Torsion angle term, E conj represents the four-body conjugate term, E vdWaals represents the van der Waals interaction term, E Coulomb represents the Coulomb force term.

[0060] Specifically, in step (2), molecular dynamics simulation parameters are set in the command file, and the molecular dynamics simulation parameters include x, y, and z boundary conditions, ensemble type, sliding velocity, temperature control method, calculation method, and time step. Among the x, y, and z boundary conditions, contraction boundary conditions are used in the x and y directions, and periodic boundary conditions are used in the z direction; the ensemble type is the NVE ensemble, which has no energy or particle exchange with the outside world, and the particle system described is an isolated and conservative system. The number of particles (N), box volume (V), and total energy (E) in the system remain unchanged; the nanoscale sliding velocity is generally set at tens to hundreds of m / s; the temperature control method is the Langevin temperature control method; the calculation method is the Verlet algorithm; and the time step is set to 0.25 fs.

[0061] Specifically, in step (2), the assembly process of the single crystal diamond hemisphere model and the carbon fiber model is: exporting the single crystal diamond hemisphere model and the carbon fiber model into a coordinate information file, obtaining the coordinate information of each atom in the single crystal diamond hemisphere model and the carbon fiber model from the coordinate information file, and summarizing the coordinate information into a data file to realize the assembly of the single crystal diamond hemisphere model and the carbon fiber model.

[0062] Specifically, in step (2), the statistical method for the number of interface bonds between the single crystal diamond hemisphere model and the carbon fiber model is as follows: use Matlab software to write a data processing program file, extract the atomic coordinate information of the Newtonian layer of the single crystal diamond hemisphere model and the Newtonian layer of the carbon fiber model in each step of the calculation process in the result file, and calculate the spatial distance L between each Newtonian layer atom of the single crystal diamond hemisphere model and the Newtonian layer atom of the carbon fiber model, as shown in Formula 2. Among them, x d 、y d 、z f They are the x, y, and z coordinates of the atoms in the single crystal diamond hemisphere model, x f 、y f 、z f They are the x, y, and z coordinates of the atoms in the carbon fiber model respectively; by calculating whether the spatial distance L between diamond and carbon fiber atoms reaches the cutoff radius To determine whether an interface bond is formed between diamond and carbon fiber, and thus obtain the number of interface bonds formed between diamond and carbon fiber in each step;

[0063] The statistical method for calculating the wear amount of the single-crystal diamond hemisphere model comprises: using Matlab software to write a data processing program file, extracting the initial atomic coordinate information of the single-crystal diamond hemisphere model and the atomic coordinate information of each step in the calculation process from the result file, first determining the coordination information of atom m and surrounding atoms in the initial state by using the initial atomic spatial distance L, then calculating the coordination status of each atom in the single-crystal diamond hemisphere model in each step, comparing the coordination information of each atom in the single-crystal diamond hemisphere model in each step with the coordination information of each atom in the initial state, and if a coordination change occurs, it is considered that the diamond atom has been worn, thereby obtaining the amount of diamond atom wear in each step.

[0064] See Figure 2 The tool wear behavior of diamond ball head scratching carbon fiber with different fiber orientations (0°, 45°, 90°, 135°) was studied using nanomolecular dynamics simulation method. Figure 2 In the figure, (a) is the statistical result of the number of CC bonds at the diamond-carbon fiber interface; (b) is the statistical result of the number of wear atoms; (c) is the atomic-level chemical wear phenomenon of the single-crystal diamond hemisphere model. Figure 2 (a) It can be seen that the number of CC bonds generated when the diamond ball head is scratched with 0° and 135° carbon fibers is the largest, while the number of CC bonds generated when it is scratched with 90° carbon fibers is the second largest, and the number of CC bonds generated when it is scratched with 45° carbon fibers is the smallest. Figure 2 (b) It can be seen that the diamond ball head wears the most atoms when it is scratched with carbon fibers at 0° and 135°, while the diamond ball head wears the least atoms when it is scratched with carbon fibers at 0° and 135°. The above results indicate that the difference in the number of stable CC bonds formed between the diamond ball head and the carbon fibers when scratching different fiber orientations leads to the difference in the wear of the diamond ball head, which explains the difference in the wear of the diamond ball head when scratching different fiber orientations. Open the .lammpstrj file in the VMD visualization software, set it to display only the diamond model, and observe the atomic-level chemical wear phenomenon of the single-crystal diamond hemisphere model during the interaction process. The results are shown in 2(c). It is found that the stable diamond structure in the diamond ball head is converted into an unstable sp 1 、sp 2 The transformation and distortion of the diamond crystal structure will reduce its own hardness, making the tool more susceptible to wear.

[0065] In summary, it was found that when scratching different fiber orientations, the number of stable C-C bonds formed between the diamond ball head and the carbon fiber was different, which led to the difference in diamond ball head wear. It was found that the stable diamond structure was converted into unstable sp 1 、sp 2 The structure reduces the hardness of the diamond ball head itself, making the tool more susceptible to wear.

[0066] The above disclosure is only a preferred embodiment of the present invention, and it is certainly not intended to limit the scope of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiment and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A method for studying the multi-scale wear behavior of diamond-coated cutting tools, characterized by: The method comprises the following steps: (1) obtaining the mechanical wear behavior between grains of polycrystalline diamond coating and between coating and substrate at a microscopic scale, wherein the specific steps are as follows: S1: Using a finite element simulation method, a micro-geometric model is established, wherein the micro-geometric model includes a diamond coating grain model, a tool substrate model, and a carbon fiber composite material unidirectional plate micro-model; S2: Assign material properties to the diamond coating grain model, tool substrate model, and carbon fiber composite unidirectional plate micromodel respectively. Use zero-thickness elements for the diamond coating grain boundaries and the coating-substrate interface, and mesh the above models. S3: Assembling the diamond coating grain model and the tool substrate model together to form a diamond coating tool model, and assembling the diamond coating tool model and the carbon fiber composite material unidirectional plate micromodel together in a right-angle cutting manner to form a tool model; S4: Setting cutting speed parameters for the tool in the tool model, setting fixed constraints for the workpiece material, and performing cutting simulation tests; wherein, the carbon fiber three-dimensional linear elastic constitutive algorithm is introduced in combination with the Vumat subroutine to describe the failure of the carbon fiber composite unidirectional plate, and the cohesive unit is used to describe the fracture failure between the diamond coating grains and between the coating and the substrate; S5: Submit the tool model, read the solution result file, analyze the stress and strain distribution of the diamond-coated tool during the cutting process according to the solution result file, and obtain the mechanical wear behavior of the polycrystalline diamond-coated tool within the crystal, between the crystals, and between the coating and the substrate; (2) Obtaining the atomic-level chemical wear behavior of single-crystal diamond at the nanoscale, the specific steps include: S1: Using molecular dynamics methods, establishing a nanoscopic geometric model, wherein the nanoscopic geometric model includes a single crystal diamond hemisphere model and a carbon fiber model; S2: Assembling the single crystal diamond hemisphere model and the carbon fiber model, and setting three layers of Newtonian layer, constant temperature layer and boundary layer on the diamond hemisphere and carbon fiber model respectively; S3: Select a potential function that can describe the sliding friction system between the single crystal diamond hemisphere model and the carbon fiber model; S4: setting molecular dynamics simulation parameters; S5: Retrieving the data files and command files of the single crystal diamond hemisphere model and the carbon fiber model to start calculation and generate result files; S6: Counting the number of interface bonds between the single crystal diamond hemisphere model and the carbon fiber model and the wear amount of the single crystal diamond hemisphere model according to the result file; S7: Use VMD visualization software to open the result file, set it to display only the diamond model, and observe the atomic-level chemical wear behavior of single crystal diamond; (3) The multi-scale wear behavior of the diamond coating tool is obtained based on the mechanical wear behavior between the diamond coating grains and between the coating and the substrate and the atomic-level chemical wear behavior of the single-crystal diamond.

2. The method for studying multi-scale wear behavior of diamond-coated cutting tools according to claim 1, wherein: In step (1), the process of establishing the diamond coating grain model and the tool substrate model is as follows: first, the code is compiled using the Python language, the required number of grains and substrate size are set, the Voronoi library is called to generate seed points for controlling the size and shape of the grains, and then the code is read using Abaqus, the grain substrate is automatically generated in Abaqus, the corresponding model is established in Abaqus, and then the diamond coating model and tool substrate model with the grain geometric characteristics are cut out.

3. The method for studying multi-scale wear behavior of diamond-coated cutting tools according to claim 1, wherein: In step (1), the process of establishing the microscopic model of the carbon fiber composite material unidirectional plate is as follows: in Abaqus, a microscopic model of the carbon fiber composite material unidirectional plate combined with fibers and resin is established.

4. The method for studying multi-scale wear behavior of diamond-coated cutting tools according to claim 1, wherein: In step (2), the process of establishing the nanoscale single crystal diamond hemisphere model is as follows: using Material studio software to establish a nanoscale single crystal diamond cube model, using Matlab to write a program to intercept a single crystal diamond cube with a radius of The simplified model of the single crystal diamond hemispherical scratching head is obtained to obtain the nanoscale single crystal diamond hemispherical model.

5. The method for studying multi-scale wear behavior of diamond-coated cutting tools according to claim 1, wherein: In step (2), the process of establishing the carbon fiber model is as follows: using Material studio software to establish a three-layer length L1 Width L2 The carbon ring basic unit is filled with the carbon ring basic unit at a density of N g / cm3 in the length X Width Y High Z The carbon fiber model is obtained by minimizing the energy and performing heat treatment on the virtual box, and the length direction of the carbon ring basic unit is distributed at ±10° along the length direction of the box.

6. The method for studying multi-scale wear behavior of diamond-coated cutting tools according to claim 1, wherein: In step (2), the potential function is the ReaxFF reaction potential function, as shown in formula 1; E system =E bond +E over +E under +E val +E pen +E tors +E conj +E vdWaals +E Coulomb (1); where E system represents the total potential energy of the system, E bond represents the bond energy term, E over represents the over-coordination energy correction term, E under represents the insufficient coordination energy correction term, E val represents the bond angle energy term, E pen represents the valence bond correction term, E tors Torsion angle term, E conj represents the four-body conjugate term, E vdWaals represents the van der Waals interaction term, E Coulomb represents the Coulomb force term.

7. The method for studying multi-scale wear behavior of diamond-coated cutting tools according to claim 1, wherein: In step (2), the molecular dynamics simulation parameters include x, y, z three-dimensional boundary conditions, ensemble type, sliding speed, temperature control method, calculation method, and time step.

8. The method for studying multi-scale wear behavior of diamond-coated cutting tools according to claim 1, wherein: In step (2), the assembly process of the single crystal diamond hemisphere model and the carbon fiber model is as follows: exporting the single crystal diamond hemisphere model and the carbon fiber model as a coordinate information file, obtaining the coordinate information of each atom in the single crystal diamond hemisphere model and the carbon fiber model from the coordinate information file, and summarizing the coordinate information into a data file to realize the assembly of the single crystal diamond hemisphere model and the carbon fiber model.

9. The method for studying multi-scale wear behavior of diamond-coated cutting tools according to claim 1, wherein: In step (2), the statistical method for the number of interface bonds between the single crystal diamond hemisphere model and the carbon fiber model is as follows: use Matlab software to write a data processing program file, extract the atomic coordinate information of the Newtonian layer of the single crystal diamond hemisphere model and the Newtonian layer of the carbon fiber model in each step of the calculation process in the result file, and calculate the spatial distance L between each Newtonian layer atom of the single crystal diamond hemisphere model and the Newtonian layer atom of the carbon fiber model, as shown in Formula 2. Among them, x d 、y d 、z f They are the x, y, and z coordinates of the atoms in the single crystal diamond hemisphere model, x f 、y f 、z f They are the x, y, and z coordinates of the atoms in the carbon fiber model respectively; by calculating whether the spatial distance L between diamond and carbon fiber atoms reaches the cutoff radius To determine whether an interface bond is formed between diamond and carbon fiber, and thus obtain the number of interface bonds formed between diamond and carbon fiber in each step; The statistical method for calculating the wear amount of the single-crystal diamond hemisphere model comprises: using Matlab software to write a data processing program file, extracting the initial atomic coordinate information of the single-crystal diamond hemisphere model and the atomic coordinate information of each step in the calculation process from the result file, first determining the coordination information of atom m and surrounding atoms in the initial state by using the initial atomic spatial distance L, then calculating the coordination status of each atom in the single-crystal diamond hemisphere model in each step, comparing the coordination information of each atom in the single-crystal diamond hemisphere model in each step with the coordination information of each atom in the initial state, and if a coordination change occurs, it is considered that the diamond atom has been worn, thereby obtaining the amount of diamond atom wear in each step.

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