Diamond coating cutter multi-scale wear behavior research method

Abstract

The invention provides a diamond coating cutter multi-scale wear behavior research method, and belongs to the technical field of diamond coating cutter wear research. Firstly, in the field of micro finite element simulation, a micro geometric model is established, and parameters such as material attributes and grid sizes are set for the micro geometric model; analyzing a stress-strain distribution rule of the cutter according to a simulation result, so as to obtain intra-crystal, inter-crystal and inter-coating matrix micromechanical wear behaviors of the polycrystalline coating from a microscale; meanwhile, in the field of molecular dynamics, by establishing a nano-scale geometric model, setting a reaction potential function, setting an atomic layer, a temperature controller and other parameters, bond formation and breaking conditions among atoms are analyzed according to a simulation result, so that the atomic-scale chemical wear behavior of the single crystal diamond is obtained from the nano-scale; and finally, the multi-scale wear behavior of the diamond coating cutter is obtained by combining the micro-mechanical wear behavior and the atomic-scale chemical wear behavior of the single crystal diamond.

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 the fields of energy, transportation, etc. is a concentrated reflection of a country's comprehensive manufacturing strength. Energy, economic and military competition forces such high-end equipment to continuously improve its working efficiency. The use of advanced materials is one of the fundamental ways to improve equipment performance. The better the performance of the workpiece material, the worse its machinability will inevitably lead to more serious tool wear in the process of machining difficult-to-machine materials such as carbon fiber composite materials.

[0003] Diamond coated tools have gradually become the first choice for machining difficult-to-machine materials such as carbon fiber composites due to their high hardness and high wear resistance. However, under conditions of large cutting volume and high cutting speed, diamond coated tools still cannot meet the continuous high-quality and high-efficiency machining requirements of difficult-to-machine materials such as large-size high-performance carbon fiber composites. Therefore, understanding the wear behavior of such tools is the basis for 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 of the tools and the superficial wear forms such as abrasive wear and fatigue wear. The disadvantage is that it is impossible to study the wear behavior of the tools in a deeper level, and only a limited sample interval can be selected to observe the wear behavior of the tools, resulting in an incomplete description of the wear behavior of the tools.

[0005] In existing research, a Chinese invention patent with patent number CN202110253578.8 discloses a method for simulating the friction and wear process of nanoscale diamond based on molecular dynamics. This scheme uses molecular dynamics to simulate the microstructural changes and stress results of nanoscale diamond during the friction and wear process, and mainly analyzes the influence of temperature changes on the wear process of nanoscale diamond. However, existing research lacks analysis of the influence of mechanical properties between coatings and substrates, coating grains, and chemical reactions between interfaces on the wear behavior of diamond tools, resulting in the current analysis of the wear behavior of diamond tools being not comprehensive enough. 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 reaction between interfaces on tool wear behavior, so as to make the analysis of diamond tool wear behavior more comprehensive.

[0007] The technical solution adopted by the present invention to solve the technical problem is as follows:

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

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

[0010] S1: using a finite element simulation method to establish a micro-geometry model, wherein the micro-geometry model includes a diamond coating grain model, a tool matrix model, and a carbon fiber composite material unidirectional plate micro-model;

[0011] S2: assigning material properties to the diamond coating grain model, tool substrate model, and carbon fiber composite material unidirectional plate microscopic model respectively, using zero-thickness units for the diamond coating grain boundaries and the coating-substrate interface, and meshing 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 microscopic model together in a right-angle cutting manner to form a tool model;

[0013] S4: Setting cutting speed parameters for the tool in the tool model, setting fixed constraints for the workpiece material, and conducting cutting simulation tests; wherein, the carbon fiber three-dimensional linear elastic constitutive algorithm is introduced in combination with the Vumat subroutine to describe the damage of the carbon fiber composite unidirectional plate, and the cohesive unit is used to describe the fracture damage of the diamond coating grains within the crystal, between the crystals, 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 method 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 Newton layer, constant temperature layer and boundary layer on the diamond hemisphere and the carbon fiber model respectively;

[0018] S3: Selecting 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 file and command file of the single crystal diamond hemisphere model and the carbon fiber model to start calculation and generate a result file;

[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: Open the result file using VMD visualization software, 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-coated 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 grain size and shape, and then abaqus is used to read the code, and the grain substrate is automatically generated in abaqus, and 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 nanoscale 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: 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 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 bond correction term, E tors Torsion angle term, E conj represents the four-body conjugation 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 aggregating 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 Newton layer of the single crystal diamond hemisphere model and the Newton layer of the carbon fiber model in each step of the calculation process in the result file, and allowing each Newton layer atom of the single crystal diamond hemisphere model to calculate the spatial distance L with the Newton layer atom of the carbon fiber model, as shown in Formula 2, Among them, x d ,y d 、z f are the x, y, and z coordinates of the atoms in the single crystal diamond hemisphere model, respectively. f ,y f 、z fare 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, thereby obtaining the number of interface bonds formed between diamond and carbon fiber in each step;

[0032] The statistical method for the wear amount of the single crystal diamond hemisphere model is as follows: 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 in the result file, firstly judging the coordination information of the atom m and the surrounding atoms in the initial state by the initial atomic space distance L, and then calculating the coordination 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, if a coordination change occurs, it is considered that the diamond atom is worn, thereby obtaining the wear amount of the diamond atom in each step.

[0033] It can be seen from the above technical scheme that the present invention provides a method for studying the multi-scale wear behavior of diamond-coated tools. Compared with the prior art, the present invention has the following beneficial effects: first, in the field of microscopic finite element simulation, by establishing a microscopic geometric model, setting material properties, grid size and other parameters for the microscopic geometric model, and analyzing the stress-strain distribution law of the tool according to the simulation results, the microscopic mechanical wear behavior within the polycrystalline coating, between the crystals, and between the coating substrates is obtained 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 atomic layers, temperature controllers and other parameters, the formation and breaking of bonds between atoms are analyzed according to the simulation results, so as to obtain the atomic-level chemical wear behavior of single-crystal diamond from the nanoscopic scale; finally, the multi-scale wear behavior of diamond-coated tools is obtained by combining the microscopic mechanical wear behavior and the atomic-level chemical wear behavior of single-crystal diamond, so that the analysis of the wear behavior of diamond tools is 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 This is a schematic diagram of the 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 described in detail 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 a diamond-coated tool, comprising the following steps:

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

[0040] S1: using a finite element simulation method to establish a micro-geometry model, wherein the micro-geometry model includes a diamond coating grain model, a tool matrix model, and a carbon fiber composite material unidirectional plate micro-model;

[0041] S2: assigning material properties to the diamond coating grain model, tool substrate model, and carbon fiber composite material unidirectional plate microscopic model respectively, using zero-thickness units for the diamond coating grain boundaries and the coating-substrate interface, and meshing 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 microscopic model together in a right-angle cutting manner to form a tool model;

[0043] S4: Setting cutting speed parameters for the tool in the tool model, setting fixed constraints for the workpiece material, and conducting cutting simulation tests; wherein, the carbon fiber three-dimensional linear elastic constitutive algorithm is introduced in combination with the Vumat subroutine to describe the damage of the carbon fiber composite unidirectional plate, and the cohesive unit is used to describe the fracture damage of the diamond coating grains within the crystal, between the crystals, 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 method 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 Newton layer, constant temperature layer and boundary layer on the diamond hemisphere and the carbon fiber model respectively;

[0048] S3: Selecting 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 file and command file of the single crystal diamond hemisphere model and the carbon fiber model to start calculation and generate a result file;

[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: Open the result file using VMD visualization software, 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-coated 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 firstly establishes a microscopic geometric model in the field of microscopic finite element simulation, sets material properties, grid size and other parameters 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, a nanoscopic geometric model is established, reaction potential functions are set, atomic layers, temperature controllers and other parameters are set, and the formation and breaking of bonds between atoms are analyzed according to the simulation results, so as to obtain the atomic-level chemical wear behavior of single-crystal diamond from the nanoscopic scale; finally, the multi-scale wear behavior of diamond-coated tools is obtained by combining the microscopic mechanical wear behavior and the atomic-level chemical wear behavior of single-crystal diamond, 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 grain size and shape, and then abaqus is used to read the code, and the grain substrate is automatically generated in abaqus, and 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.

[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 nanoscale 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.

[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 bond correction term, E tors Torsion angle term, E conj represents the four-body conjugation 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, z three-dimensional boundary conditions, ensemble type, sliding speed, temperature control method, calculation method, and time step. Among the x, y, z three-dimensional 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 adopts the NVE ensemble, which has no energy and particle exchange with the outside world, and the particle system described is an isolated and conservative system, and the number of particles (N), box volume (V), and total energy (E) in the system remain unchanged; the nanoscale of the sliding speed is generally set at tens to hundreds of m / s; the temperature control method uses the Langevin temperature control method; the calculation method uses the Verlet algorithm; and the time step is set to 0.25fs.

[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 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 aggregating 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: use Matlab software to write a data processing program file, extract the atomic coordinate information of the Newton layer of the single crystal diamond hemisphere model and the Newton 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 Newton layer atom of the single crystal diamond hemisphere model and the Newton layer atom of the carbon fiber model, as shown in Formula 2, Among them, x d ,y d 、z f are the x, y, and z coordinates of the atoms in the single crystal diamond hemisphere model, respectively. f ,y f 、z f 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, thereby obtaining the number of interface bonds formed between diamond and carbon fiber in each step;

[0063] The statistical method for the wear amount of the single crystal diamond hemisphere model is as follows: 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 in the result file, firstly judging the coordination information of the atom m and the surrounding atoms in the initial state by the initial atomic space distance L, and then calculating the coordination 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, if a coordination change occurs, it is considered that the diamond atom is worn, thereby obtaining the wear amount of the diamond atom in each step.

[0064] See also 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 has the most atoms worn when scratching the carbon fiber at 0° and 135°, while the diamond ball head has the least atoms worn when scratching the carbon fiber at 0° and 135°. The above results show that the difference in the number of stable CC bonds formed between the diamond ball head and the carbon fiber when scratching different fiber orientations leads to the difference in diamond ball head wear, which explains the difference in diamond ball head wear 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 CC bonds formed between the diamond ball head and the carbon fiber was different, which led to the difference in the wear of the diamond ball head. It was found that the stable diamond structure was converted into an unstable sp 1 、sp 2 The structure reduces the hardness of the diamond ball head itself, making the tool more susceptible to wear.

[0066] What is disclosed above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for studying the multi-scale wear behavior of diamond-coated 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 to establish a micro-geometry model, wherein the micro-geometry model includes a diamond coating grain model, a tool matrix model, and a carbon fiber composite material unidirectional plate micro-model; S2: assigning material properties to the diamond coating grain model, tool substrate model, and carbon fiber composite material unidirectional plate microscopic model respectively, using zero-thickness units for the diamond coating grain boundaries and the coating-substrate interface, and meshing 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 microscopic model 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 conducting cutting simulation tests; wherein, the carbon fiber three-dimensional linear elastic constitutive algorithm is introduced in combination with the Vumat subroutine to describe the damage of the carbon fiber composite unidirectional plate, and the cohesive unit is used to describe the fracture damage between 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 method to establish 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 Newton layer, constant temperature layer and boundary layer on the diamond hemisphere and the carbon fiber model respectively; S3: Selecting 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 file and command file of the single crystal diamond hemisphere model and the carbon fiber model to start calculation and generate a result file; 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: Open the result file using VMD visualization software, 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-coated 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, characterized in that: 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 grain size and shape, and then abaqus is used to read the code, and 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 grain geometric characteristics are cut out.

3. The method for studying multi-scale wear behavior of diamond-coated cutting tools according to claim 1, characterized in that: 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, characterized in that: 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 nanoscale 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.

5. The method for studying multi-scale wear behavior of diamond-coated cutting tools according to claim 1, characterized in that: 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, characterized in that: 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 bond correction term, E tors Torsion angle term, E conj represents the four-body conjugation 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, characterized in that: In step (2), the molecular dynamics simulation parameters include x, y, z 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, characterized in that: 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 aggregating 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, characterized in that: 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 Newton layer of the single crystal diamond hemisphere model and the Newton layer of the carbon fiber model in each step of the calculation process in the result file, and allowing each Newton layer atom of the single crystal diamond hemisphere model to calculate the spatial distance L with the Newton layer atom of the carbon fiber model, as shown in Formula 2, Among them, x d ,y d 、z f are the x, y, and z coordinates of the atoms in the single crystal diamond hemisphere model, respectively. f ,y f 、z f 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, thereby obtaining the number of interface bonds formed between diamond and carbon fiber in each step; The statistical method for the wear amount of the single crystal diamond hemisphere model is as follows: 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 in the result file, firstly judging the coordination information of the atom m and the surrounding atoms in the initial state by the initial atomic space distance L, and then calculating the coordination 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, if a coordination change occurs, it is considered that the diamond atom is worn, thereby obtaining the wear amount of the diamond atom in each step.

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