Method and related apparatus for simulating indentation and grinding dynamic processes on graphene-sic composite substrate surface based on molecular dynamics

Abstract

The application discloses a method for simulating the surface indentation and grinding dynamic process of a graphene-SiC composite substrate based on molecular dynamics and a related device, and belongs to the technical field of computational materials. Different potential functions are selected to describe the interaction between atoms in a layered atomic model of a diamond indenter / graphene layer / single crystal SiC substrate, the boundary and temperature control are set, and the layered model is relaxed to the minimum energy, the diamond indenter is controlled to be pressed in the direction perpendicular to the surface of the single crystal SiC substrate, and then is controlled to move in the direction parallel to the surface of the single crystal SiC substrate and the plane of the graphene layer, the surface indentation and grinding dynamic process of the graphene-SiC composite substrate are simulated respectively, the simulation results are output, and the mechanical behavior in the surface indentation and grinding dynamic process of the graphene-SiC composite substrate is analyzed. By establishing a full-atomic model of the graphene-SiC composite substrate and controlling the movement process of the diamond indenter, the nanoindentation and nanogrinding processes can be simulated.

Description

Technical Field

[0001] This invention belongs to the field of computational materials technology, specifically relating to a method and related apparatus for simulating the dynamic process of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics. Background Technology

[0002] In cutting-edge fields such as micro- and nano-electro-mechanical systems (MEMS / NEMS), advanced semiconductor devices, and ultra-precision machining, silicon carbide (SiC) has become a core substrate material due to its superior properties such as high hardness, high temperature resistance, and radiation resistance, holding an irreplaceable position in related device manufacturing and precision machining scenarios. However, SiC's inherent high brittleness and low fracture toughness make it prone to subsurface damage and crack propagation during key processing steps such as nanoindentation and nanogrinding, severely restricting the improvement of device processing accuracy and long-term reliability.

[0003] To address this challenge, graphene, with its ultra-low shear strength and unique interlayer slip effect, has been widely applied in the modification research of SiC composite substrates. The aim is to reduce the friction coefficient and suppress damage during processing through its lubricating effect, while simultaneously optimizing the surface and interfacial mechanical properties of SiC-based composite materials. Against this backdrop, accurately revealing the microscopic mechanisms of graphene-SiC composite substrates in dynamic processes such as nanoindentation and nanogrinding has become a core requirement for optimizing material design and ultra-precision machining processes.

[0004] Nanoindentation, a key experimental technique for characterizing the interfacial mechanical behavior of ceramic matrix composites such as SiC, can obtain macroscopic performance parameters such as hardness and elastic modulus. While atomic force microscopy and other experimental tools have confirmed the anti-grinding effect of graphene on SiC surfaces, traditional experimental methods are limited by the observation scale and dynamic capture capability. They struggle to directly observe the atomic trajectories and microstructural evolution during indentation at the atomic scale, as well as the atomic-level removal paths and real-time dynamic mechanisms of graphene lubrication during grinding. Consequently, a direct correlation between macroscopic properties and microscopic behavior cannot be established.

[0005] Molecular dynamics (MD) simulations, as an effective tool for revealing microscopic mechanisms at the atomic scale, compensate for the limitations of experimental methods and provide an important approach for studying the deformation behavior and interfacial interaction mechanisms of SiC-based composite materials. Existing MD simulation studies have made preliminary progress in indentation and grinding processes of pure SiC materials, or in characterizing the mechanical properties of single graphene films, achieving some advancements in the evolution of material microstructures (such as phase transitions and dislocation evolution) and energy dissipation. However, existing MD simulation methods are insufficient in revealing the correlation between the interfacial interaction between graphene and the SiC substrate in composite systems, the evolution of graphene structures (wrinkling, fracture, interlayer slip), and macroscopic mechanical responses and processing effects, failing to fully meet the practical needs of composite substrate material design and processing optimization. Therefore, developing a molecular dynamics method that can systematically and accurately simulate the dynamic processes of nanoindentation and nanogrinding on the surface of graphene-SiC composite substrates, quantifying the influence of graphene on indenter / cutting force, material removal behavior and damage evolution, and elucidating its lubrication and regulation mechanisms, is of great theoretical and practical significance for promoting the application of SiC-based composite materials in cutting-edge device fields and optimizing ultra-precision machining processes. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the present invention aims to provide a method and related apparatus for simulating the dynamic process of indentation and grinding on the surface of graphene-SiC composite substrates based on molecular dynamics simulation, so as to solve the technical problem that the existing MD simulation method cannot fully reveal the dynamic process on the surface of graphene-SiC composite substrates.

[0007] To achieve the above objectives, the present invention employs the following technical solution: The first aspect of this invention discloses a method for simulating the dynamic processes of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics simulation. The method defines the integrated heterogeneous substrate material formed by in-situ epitaxial composite graphene layers on the surface of a single-crystal SiC substrate as a graphene-SiC composite substrate, and includes the following steps: Different potential functions were selected to describe the interactions between atoms in the layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix, respectively, and potential function description models were obtained. By setting boundaries and temperature-controlled stratification for the potential function description model and relaxing it to the minimum energy, a layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix with stable energy is obtained. In the energy-steady diamond indenter / graphene layer / single-crystal SiC matrix layered atomic model, the diamond indenter is controlled to press down in a direction perpendicular to the surface of the single-crystal SiC matrix, and then move in a direction parallel to the surface of the single-crystal SiC matrix and the plane of the graphene layer, respectively simulating the dynamic process of indentation and grinding on the surface of the graphene-SiC composite substrate. Output simulation results to analyze the mechanical behavior of the graphene-SiC composite substrate surface during indentation and grinding dynamic processes.

[0008] Preferably, the method for constructing the layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix is ​​as follows: using LAMMPS software, with the in-plane direction of the crystal as the x-axis and y-axis and a periodic boundary, and the direction perpendicular to the surface of the single-crystal SiC matrix as the z-axis and a fixed boundary condition, with the geometric center of the lower surface of the single-crystal SiC matrix as the origin of the coordinate system, a single-crystal SiC matrix is ​​constructed in the z-axis direction, a graphene layer is constructed on top of the single-crystal SiC matrix, and the diamond indenter is placed on top of the graphene layer to obtain the layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix.

[0009] More preferably, the size of the single-crystal SiC substrate is 150 Å × 150 Å × 80 Å, and the size of the graphene layer is 160 Å × 160 Å.

[0010] Preferably, SiC adopts a 3C-SiC cubic lattice with a lattice constant of 4.36 Å; the diamond indenter adopts a diamond cubic crystal structure with a lattice constant of 3.57 Å; and the graphene adopts a hexagonal lattice with a lattice constant of 2.45 Å.

[0011] Preferably, the step of selecting the potential function is as follows: the interaction between atoms inside the single-crystal SiC matrix is ​​described by the SiC Tersoff potential function, the interaction between carbon atoms inside the graphene layer is described by the CH airebo potential function, and the interatomic interactions between the graphene layer and the diamond indenter, between the graphene layer and the single-crystal SiC matrix, and between the diamond indenter and the single-crystal SiC matrix are all described by the Lennard Jones potential function.

[0012] Preferably, the temperature-controlled layering step is as follows: in the layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix, a fixed layer, a temperature-controlled layer, and a Newton layer are defined for the single-crystal SiC matrix. The atoms in the fixed layer are set to a fixed state. A temperature-controlled layer with a constant atomic temperature is continuously constructed above the fixed layer. A Newton layer is continuously constructed above the temperature-controlled layer. The atomic temperature of the Newton layer changes with the movement of the indenter and the interatomic interaction potential function. At the same time, the atomic groupings within the single-crystal SiC matrix and the fixed boundary regions of the graphene layer are defined. The graphene layer is divided into graphene fixed atom groups, and the remaining graphene layer atoms are assigned to Newton groups.

[0013] Preferably, the output simulation results include the load-displacement curves of the diamond indenter during the pressing and unloading processes, and the changes in temperature and stress field during the grinding process of the diamond indenter on the graphene-SiC composite substrate surface.

[0014] A second aspect of the present invention discloses a system for simulating the dynamic processes of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics simulation, comprising: The potential function description model construction module is used to select different potential functions to describe the interactions between atoms in the layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix, and obtain the potential function description model; The layered atomic model construction module is used to set boundaries and temperature-controlled layering of the potential function description model and relax it to the minimum energy to obtain an energy-steady layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix. The dynamic process simulation module for indentation and grinding is used to control the diamond indenter to press down along the direction perpendicular to the surface of the single crystal SiC substrate in the energy steady-state layered atomic model of diamond indenter / graphene layer / single crystal SiC substrate, and then move along the direction parallel to the surface of the single crystal SiC substrate and the plane of the graphene layer, respectively simulating the dynamic process of indentation and grinding on the surface of graphene-SiC composite substrate. The results output module is used to output simulation results and analyze the mechanical behavior of the graphene-SiC composite substrate surface during the dynamic process of indentation and grinding.

[0015] A third aspect of the present invention discloses a computer device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described above for simulating the dynamic process of indentation and grinding of a graphene-SiC composite substrate surface based on molecular dynamics.

[0016] A fourth aspect of the present invention discloses a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method described above for simulating the dynamic process of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for simulating the dynamic processes of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics. By establishing a full-atomic model of the graphene-SiC composite substrate and controlling the movement of the diamond indenter, it simulates both nanoindentation and nanogrinding processes, thereby achieving full-atomic simulation of the changes in the substrate surface morphology and internal microstructure during these two processes. Specifically: 1) By selecting suitable potential functions for the layered atomic model of the diamond indenter / graphene layer / single-crystal SiC substrate to match the interactions between different atoms, the methods accurately describe the forces within the SiC substrate, the graphene, and between the components, avoiding simulation distortion of interatomic interactions due to potential function mismatch, and ensuring accurate calculation of physical quantities such as stress and load during the simulation; 2) Clearly defining the model boundary conditions effectively constrains the range of atomic movement in the system; temperature-controlled layering allows for precise control... The simulation temperature is kept stable within the target range to ensure that the simulation process is in a constant temperature environment, while distinguishing the motion characteristics of different atomic groups; 3) The internal stress generated during the model construction process can be eliminated through relaxation treatment, so that the atomic configuration reaches the initial stable state and avoids simulation deviation caused by initial stress; Energy steady-state optimization can further reduce the total energy of the system, ensuring that the initial state of the simulation meets the thermodynamic equilibrium conditions, and providing a stable initial model for subsequent simulation of the grinding dynamic process; 4) The simulation is carried out in the order of "pressing down perpendicular to the surface of the single crystal SiC substrate → moving parallel to the surface of the single crystal SiC substrate and the plane of the graphene layer", which fits the actual nano-grinding process flow. It can accurately capture the contact, extrusion and grinding process between the indenter and the composite substrate, and restore the stress deformation of the graphene layer, the wear of the SiC substrate and the formation of grinding debris in real time, and accurately simulate the dynamic response under different grinding conditions.In summary, this method offers several advantages: First, it can capture the full dynamic process of the graphene-SiC composite substrate surface in real time at atomic resolution, clearly observing the key influence of the graphene lubricating layer on the material response during indentation and the material removal mechanism during grinding. Simultaneously, it accurately tracks the dynamic evolution of the atomic temperature field (atomic temperature) and stress field (atomic stress tensor) within SiC, providing direct observational evidence for analyzing the microscopic mechanisms. Second, it can not only systematically analyze the dynamic fracture, deformation, and failure mechanisms of graphene during indentation and grinding, but also clarify the microscopic mechanism of material removal from the composite substrate during grinding, establishing the intrinsic correlation between graphene behavior and the macroscopic response of the material. Third, it can... This method achieves precise integration of atomic-scale processes and macroscopic performance. Firstly, it establishes a quantitative correlation between graphene behavior and indenter load-displacement curve changes, as well as microscopic damage within SiC. Secondly, it links the grinding process with three-dimensional cutting force fluctuations in real time, constructing a quantitative mapping model between material microscopic behavior (such as amorphous regions and dislocation density) and macroscopic processing quality (surface roughness and damage depth). Fourthly, it effectively compensates for the lack of data sources in traditional experiments under high-speed and extremely small-scale conditions, accurately acquiring key data on material microscopic behavior and indenter / cutting force under high-speed indentation and high-speed grinding conditions, providing core data support for process research under extreme conditions. Therefore, based on the correlation analysis between microscopic mechanisms and macroscopic performance, this method can directly simulate the dynamic processes on the surface of graphene-SiC composite substrates, significantly improving the processing efficiency and reliability of SiC-based ultra-precision devices.

[0018] Furthermore, by using LAMMPS software to construct a layered atomic model of the diamond indenter / graphene layer / single-crystal SiC matrix, the spatial relationship and lattice characteristics of the three can be accurately reproduced, providing a realistic model basis for subsequent grinding dynamic simulation. Attached Figure Description

[0019] Figure 1 This is a flowchart of the method for simulating the dynamic process of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics, according to the present invention. Figure 2 This is a schematic diagram of the nanoindentation process of the graphene-SiC composite substrate of the present invention; wherein, (a) is the definition of the atomic region of the substrate and the description of the pressing process of the diamond nanoindenter, (b) is a three-dimensional schematic diagram of the diamond nanoindenter and the single-layer graphene-SiC model, (c) is a side view of the diamond nanoindenter and the double-layer graphene-SiC model, and (d) is a side view of the diamond nanoindenter and the triple-layer graphene-SiC model. Figure 3The diagram shows the SiC composite surface model structure with different graphene layers according to the present invention; wherein, (a) is a side view of the bare SiC model with diamond nanoindenter, (b) is a side view of the diamond nanoindenter and the single-layer graphene-SiC model, (c) is a side view of the diamond nanoindenter and the double-layer graphene-SiC model, and (d) is a side view of the diamond nanoindenter and the triple-layer graphene-SiC model. Figure 4 The simulation results show the surface morphology changes of bare SiC nanoindentation in this invention; from left to right, they represent the surface morphology changes of bare SiC surface during the pressing and upward movement of the diamond nanoindenter. Figure 5 The simulation results show the surface morphology changes of nanoindentation on the surface of single-layer, two-layer, and three-layer graphene-SiC composite substrates in this invention. Among them, (a) shows the surface morphology change process of the single-layer graphene-SiC surface during the pressing and moving of the diamond nanoindenter, (b) shows the surface morphology change process of the double-layer graphene-SiC surface during the pressing and moving of the diamond nanoindenter, and (c) shows the surface morphology change process of the three-layer graphene-SiC surface during the pressing and moving of the diamond nanoindenter. From left to right, these are the morphology changes of the substrate surface during the pressing and moving process. Figure 6 The present invention presents load-displacement curves of nano-indenters on SiC composite substrates with different indenter velocities and graphene layer numbers. Among them, (a) is the curve of force change in the z-direction of the indenter on the bare graphene-SiC surface during the downward and upward movement of the diamond nano-indenter, (b) is the curve of force change in the z-direction of the indenter on the single-layer graphene-SiC surface during the downward and upward movement of the diamond nano-indenter, (c) is the curve of force change in the z-direction of the indenter on the double-graphene-SiC surface during the downward and upward movement of the diamond nano-indenter, and (d) is the curve of force change in the z-direction of the indenter on the triple-graphene-SiC surface during the downward and upward movement of the diamond nano-indenter. Figure 7 This is a schematic diagram of the graphene-SiC composite substrate of the present invention during the nano-grinding process of diamond particles; wherein, (a) is the nano-grinding motion of the diamond nano-indenter on the graphene-SiC composite substrate, and (b) is a three-dimensional schematic diagram of the diamond nano-indenter and the single-layer graphene-SiC model. Figure 8The diagram shows the internal stress distribution of the graphene-SiC composite substrate during nano-grinding of the present invention. Among them, (a) shows the atomic stress distribution of bare SiC during the grinding process when the indentation depth is 2 Å, (b) shows the atomic stress distribution of the graphene-SiC composite substrate during the grinding process when the indentation depth is 2 Å, (c) shows the atomic stress distribution of bare SiC during the grinding process when the indentation depth is 5 Å, (d) shows the atomic stress distribution of the graphene-SiC composite substrate during the grinding process when the indentation depth is 5 Å, (e) shows the atomic stress distribution of bare SiC during the grinding process when the indentation depth is 8 Å, and (f) shows the atomic stress distribution of the graphene-SiC composite substrate during the grinding process when the indentation depth is 8 Å. From left to right, these are the side view, front view, and three-dimensional view of the stress distribution of the model. Figure 9 The images show a comparison of the surface morphology and internal stress distribution of bare SiC and graphene-SiC composite substrates after nano-grinding in this invention. Among them, (a) is a side view of the surface morphology of bare SiC after grinding, (b) is a top view of the surface morphology of bare SiC after grinding, (c) is a side view of the surface morphology of graphene-SiC substrate after grinding, and (d) is a top view of the surface morphology of graphene-SiC substrate after grinding. Figure 10 The images show a comparison of the surface morphology and internal stress distribution of bare SiC and graphene-SiC composite substrates after nano-grinding at diamond indentation depths of 2 Å, 5 Å, and 8 Å, respectively. (a) shows the surface morphology and internal stress distribution of bare SiC after grinding at an indentation depth of 2 Å; (b) shows the surface morphology and internal stress distribution of bare SiC after grinding at an indentation depth of 5 Å; (c) shows the surface morphology and internal stress distribution of bare SiC after grinding at an indentation depth of 8 Å; (d) shows the surface morphology and internal stress distribution of graphene-SiC composite substrate after grinding at an indentation depth of 2 Å; (e) shows the surface morphology and internal stress distribution of graphene-SiC composite substrate after grinding at an indentation depth of 5 Å; and (f) shows the surface morphology and internal stress distribution of graphene-SiC composite substrate after grinding at an indentation depth of 8 Å. Figure 11 The load-displacement curves and corresponding model configurations of the diamond indenter in this invention are shown below. Among them, (a) is a comparison of the force changes of the indenter in the x direction during grinding of bare SiC substrate and graphene-SiC composite substrate when the indentation depth is 5 Å; (b) is a comparison of the force changes of the indenter in the z direction during grinding of bare SiC substrate and graphene-SiC composite substrate when the indentation depth is 5 Å; (c) is the surface morphology of bare SiC substrate during grinding when the indentation depth is 5 Å; and (d) is the surface morphology of graphene-SiC composite substrate during grinding when the indentation depth is 5 Å. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] In this article, "graphene-SiC composite substrate" refers to an integrated heterogeneous substrate material formed by in-situ epitaxial composite graphene layer on the surface of a single-crystal SiC substrate.

[0023] This invention provides a method for simulating the dynamic processes of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics, such as... Figure 1 As shown, it includes the following steps: I. Constructing a layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix 1. Parameter Settings: Atomic modeling was performed using LAMMPS software, with metal as the unit system. A standard Cartesian coordinate system was established, with the geometric center of the lower surface of the single-crystal SiC substrate as the origin. The x and y axes of the simulated box corresponded to the in-plane directions of the crystal, using periodic (p) boundary conditions. The z-axis was perpendicular to the surface of the single-crystal SiC substrate, representing the direction of interlayer stacking, indenter loading, and grinding feed, using fixed (f) boundary conditions. Key modeling parameters were initialized, including the time step, and the lattice parameters of diamond, SiC substrate, and graphene.

[0024] 2. Constructing a layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix: Within the defined simulation box and coordinate system, spatial regions of single-crystal SiC matrix, graphene layer and diamond indenter are sequentially delineated along the z-axis. The atomic type and lattice parameters of each region are defined. The single-crystal SiC matrix and graphene layer are constructed sequentially from bottom to top, and the diamond indenter is placed on top of the graphene layer to obtain the layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix.

[0025] II. Selection of Potential Function Define the mass parameters of each atom in the layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix and select the potential function; Specifically, the potential functions are selected as follows: the SiC.Tersoff potential function is used to describe the interaction between atoms inside the single-crystal SiC matrix; the CH.airebo potential function is used to define the interaction between carbon atoms inside the graphene layer; and the Lennard Jones (LJ) potential function is used to describe the interatomic interactions between the graphene layer and the diamond indenter, between the graphene layer and the single-crystal SiC matrix, and between the diamond indenter and the single-crystal SiC matrix, respectively.

[0026] III. Defining Model Boundaries and Temperature Control Layers A three-layer structure is defined for a single-crystal SiC substrate, consisting of a fixation layer, a temperature control layer, and a Newtonian layer. The characteristics of each layer are as follows: Fixed layer: atoms remain stationary; Temperature control layer: Located above the fixed layer, the atomic temperature remains constant; Newtonian layer: Located above the temperature-controlled layer, the atomic temperature changes with the movement of the diamond indenter and the interatomic interaction potential function.

[0027] IV. Model Relaxation and Energy Steady-State Optimization By setting the simulation temperature, relaxation time, and time step, and fixing the atoms within the diamond indenter, the layered atomic model of the diamond indenter / graphene layer / single-crystal SiC matrix is ​​relaxed under an isobaric and isothermal (NPT, constant particle number, constant pressure, and constant temperature) ensemble to obtain an energy-steady-state layered atomic model of the diamond indenter / graphene layer / single-crystal SiC matrix.

[0028] V. Simulation of Dynamic Grinding Process on Graphene-SiC Composite Substrate Controlling the diamond indenter to press down to a certain depth along the z-direction of the energy-steady-state diamond indenter / graphene layer / single-crystal SiC matrix layered atomic model. Figure 2 (a) and then move along the x-direction to simulate the dynamic process of pressing and grinding on the surface of the graphene-SiC composite substrate.

[0029] VI. Results Output Based on the output load and displacement data, load-displacement curves of the diamond indenter during the pressing and unloading processes are plotted. Simultaneously, the changes in temperature and stress field during the grinding process of the diamond indenter on the graphene-SiC composite substrate are acquired, generating temperature and stress distribution maps of graphene and SiC atoms. The formation process of microstructures and grinding debris near SiC trenches is captured, and the formation mechanism of graphene wrinkles and fractures is revealed through abrupt changes in cutting force. The graphene lubrication effect is explained, and the identification and causal analysis of subsurface damage depth and phase transition regions are completed.

[0030] The present invention will now be described in further detail with reference to the accompanying drawings: Example 1 Based on molecular dynamics simulations, the dynamic processes of indentation and grinding on the surface of a monolayer graphene-SiC composite substrate include the following steps: I. Constructing a layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix 1. Parameter settings A 3D model was constructed using LAMMPS software, employing metal units and atomic types. A standard Cartesian coordinate system was established, with the geometric center of the lower surface of the single-crystal SiC substrate as the origin. The x and y axes of the simulation box correspond to the in-plane directions of the crystal, using periodic (p) boundary conditions. The z-axis, perpendicular to the surface of the single-crystal SiC substrate, represents the direction of interlayer stacking, indenter loading, and grinding feed, using fixed (f) boundary conditions. Model geometry and lattice parameters were set based on measured values: the SiC substrate was a 3C-SiC cubic lattice (lattice constant 4.36 Å), the spherical diamond indenter had a diamond cubic crystal structure (lattice constant 3.57 Å), and the graphene had a hexagonal lattice (lattice constant 2.45 Å). The simulation box dimensions were 150 Å × 150 Å × 110 Å; the radius, indentation speed, and grinding steps of the spherical diamond indenter were set according to the process specifications. The simulation temperature was set to 293K, the relaxation step count was 200,000, and the time step was 0.5 fs.

[0031] 2. Constructing a layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix Within the established coordinate system and simulation box, divide the functional regions along the z-axis: 0~80 Å along the z-axis: Single-crystal 3C The SiC matrix region has a cuboid configuration with dimensions of 150 Å × 150 Å × 80 Å, and the upper surface is parallel to the x–y plane; Above 80 Å along the z-axis: Graphene layer region, with the graphene aligned with the armchair direction parallel to the x-axis and parallel to the single-crystal 3C. The SiC substrate surface is arranged with a size of 160 Å × 160 Å, and the epitaxial layer covers the SiC substrate; The spherical diamond indenter adopts a diamond cubic structure, pressing down along the z-axis and achieving grinding motion along the x-axis.

[0032] Complete the single-crystal 3C process sequentially by region. Atom filling of SiC matrix and graphene layer; placing spherical diamond indenter on single-crystal 3C At a distance of 27 Å above the SiC matrix, the center of the sphere is relative to the single-crystal 3C. The center of the SiC matrix was offset by 30 Å along the positive x-axis to match the requirements of the nano-grinding process. Finally, a layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix was constructed for simulating the dynamic process of nano-indentation and grinding of graphene-SiC composite substrates.

[0033] II. Selection of Potential Function 1. Define the mass parameters of each atom in the layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix: C atom mass is 12.01, Si atom mass is 28.09; 2. Precisely select and set the interaction potential between each atom: Single-crystal 3C The interactions between atoms within the SiC matrix are described using the SiC.Tersoff potential function provided by LAMMPS; the interactions between carbon atoms within the graphene layer are described using the CH.airebo potential function to ensure the accuracy of the interactions between atoms within the graphene layer; the interactions between the graphene layer and the spherical diamond indenter are described using the Lennard-Jones potential function, with the potential function parameters for the CC atom pairs being ε=0.0045532 eV and σ=3.4309 Å, to accommodate the interaction characteristics of both containing carbon atoms; the interactions between the graphene layer and single-crystal 3C... The interatomic interactions between SiC atoms were described using Lennard-Jones potential functions. The potential parameters for Si-C atom pairs were ε = 0.0089092 eV and σ = 3.6286 Å, while those for CC atom pairs were ε = 0.0045532 eV and σ = 3.4309 Å. (The text then mentions a spherical diamond indenter and single-crystal 3C.) The interatomic interactions between SiC matrices are described using Lennard-Jones potential functions. The potential function parameters for Si-C atom pairs are ε = 0.0089092 eV and σ = 3.6286 Å, and for CC atom pairs are ε = 0.0045532 eV and σ = 3.4309 Å. The cutoff radius for all Lennard-Jones potential functions is uniformly set to 10.5 Å to avoid interference from long-range interatomic interactions. 3. Output the layered atomic model configuration of diamond indenter / graphene layer / single-crystal SiC matrix and generate LAMMPS data file to provide basic data support for subsequent simulations.

[0034] III. Defining Model Boundaries and Temperature Control Layers After describing the potential function, the single-crystal 3C in the layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix was analyzed. The SiC matrix is ​​defined by a fixed layer, a temperature-controlled layer, and a Newtonian layer. The fixed layer has a 10 Å thickness and its atoms are set to a fixed state. Above the fixed layer, a 40 Å thick temperature-controlled layer is continuously constructed to maintain a constant atomic temperature. Above the temperature-controlled layer, a 30 Å thick Newtonian layer is continuously constructed. The atomic temperature of the Newtonian layer varies with the motion of the spherical diamond indenter and the interatomic interaction potential function. Simultaneously, a single-crystal SiC matrix is ​​defined. The atomic groups within the SiC matrix and the fixed boundary regions of the graphene layer are defined, with the graphene layer divided into fixed atom groups and the remaining graphene layer atoms assigned to Newton groups.

[0035] IV. Model Relaxation and Energy Steady-State Optimization 1. Relaxation treatment: In the layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix, the spherical diamond indenter and single-crystal 3C matrix are... The initial velocities of the fixed-layer atoms in the SiC matrix and graphene layer were set to 0, and the force on this atomic group was defined as zero using the `fix setforce` command, thus completing the atomic fixation. Subsequently, the velocity parameters were set according to the simulation requirements, and the `velocity create` command was used to define the single-crystal 3C matrix. The initial velocities of the non-fixed atomic groups in the SiC matrix and graphene layer were set to Gaussian distribution. The temperature parameter in the command was set to 293 K, and the random number was set to 12345 to generate a simulated temperature of 293 K. Then, the atomic groups were run for 10 ps under the NPT ensemble to achieve relaxation of the layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix, ensuring that the system reaches a stable state. 2. Energy Minimization Process: After relaxation, the conjugate gradient method (cg) is used to minimize the energy of the diamond indenter / graphene layer / single-crystal SiC matrix layered atomic model. The key parameters are set as follows: Etot (total energy of the system during the simulation, in eV), Ftol (force tolerance during energy minimization, in eV / Angstrom), Maxiter, and Maxeval are set to 1e-15, 1e-15, 5000, and 5000, respectively. After energy minimization, the energy-minimized diamond indenter / graphene layer / single-crystal SiC matrix layered atomic model is output.

[0036] V. Simulation of Dynamic Process of Indenter Pressing and Grinding on Graphene-SiC Composite Substrate 1. Setting the position parameters of the spherical diamond indenter: For the energy-steady-state layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix, the total displacement of the spherical diamond indenter is defined as 30 Å. This is because the initial displacement of the spherical diamond indenter relative to the single-crystal SiC matrix is... There is a 10 Å gap between the upper surfaces of the SiC matrix, so the total indentation depth of the spherical diamond indenter is 20 Å; the loading depth and speed of the spherical diamond indenter are set, where the indentation depth is determined by the function d(t) = 0.3 (Å / ps). The time step t(ps) varies linearly with time to define the position change of the spherical diamond indenter during uniform downward pressure in the z-direction. The fix move linear command is used to define the pressing and unloading processes of the spherical diamond indenter. The speed of the unloading process is the same as that of the loading process, 0.3 Å / ps, and the direction is vertically upward. The total number of unloading steps is equal to the total number of loading steps. The simulation time step is set to 0.001 ps. Based on this, the simulation step size for the pressing stage is adjusted to achieve indentation depths of 2 Å, 5 Å, and 8 Å on the substrate surface. 2. Calculation settings for relevant physical quantities: The `compute stress / atom` command is used to calculate atomic stress, based on virial stress (see the LAMMPS manual (https: / / docs.lammps.org / compute_stress_atom.html) for calculation methods); the `compute Voronoi / atom` command is used to calculate the Voronoi lattice volume, simultaneously defining the total atomic stress tensor, and the `compute temp` command is used to calculate atomic temperature (see the LAMMPS manual for calculation methods). https: / / docs.lammps.org / compute_temp.html )); 3. Load Calculation: Using the compute reduce command, force calculations are performed on the atomic group of the spherical diamond indenter, calculating the force f of the spherical diamond indenter in the x, y, and z directions respectively. x f y f z The sum of these values ​​yields the loads of the spherical diamond indenter in three directions. 4. Data and morphology output during simulation: The fix ave / time command is used to output the load of the spherical diamond indenter at a frequency of once every 100 steps, and the dump command is used to output the morphological changes of the system during the compression process of the spherical diamond indenter at a frequency of once every 1000 steps. Figure 5 (a) 5. Simulated loading control: The fix move linear command is used to complete the process of uniformly pressing down the spherical diamond indenter, holding the load at rest, and unloading the load at a uniform speed until the spherical diamond indenter returns to its initial height, thus completing the full loading-holding-unloading simulation. 6. Running the indentation process: The simulation steps are set to 150,000 steps to simulate the complete process of the spherical diamond indenter approaching and moving away from the substrate during nanoindentation. Figure 2 (b) Figure 3 (b) 7. Run the grinding process: Use the `fix move linear` command to define the uniform motion of the spherical diamond indenter in the x-direction. Simulate the grinding process on the graphene-SiC composite substrate surface by applying displacement in the x-direction. Set the number of grinding process simulation steps to 200,000 steps to simulate the dynamic grinding process. Figure 7 ).

[0037] VI. Results Output 1. Data Post-processing and Curve Plotting: Based on the output load and displacement data, plot the load-displacement curves of the spherical diamond indenter during the pressing and unloading processes. Figure 6 (b)); Simultaneously, the temperature and stress field changes during the grinding process of the spherical diamond indenter on the graphene-SiC composite substrate were obtained, and the temperature and stress distribution diagrams of the generated graphene and SiC atoms were obtained. Figure 8 (b), (d) and (f)); 2. Microscopic Mechanism and Damage Analysis: Capture the formation process of microstructure and wear debris near SiC trenches, reveal the formation mechanism of graphene wrinkles and fractures through abrupt changes in cutting force, explain the graphene lubrication effect, and complete the identification and causal analysis of subsurface damage depth and phase transition region.

[0038] Example 2 Based on molecular dynamics simulation of the dynamic process of indentation and grinding on the surface of the bilayer graphene-SiC composite substrate, the difference from Example 1 is that step 1.2 (constructing a layered atomic model of diamond indenter / graphene layer / single crystal SiC substrate) is different, while the other steps are the same.

[0039] The specific steps for constructing a layered atomic model of a diamond indenter / graphene layer / single-crystal SiC matrix are as follows: Within the established coordinate system and simulation box, divide the functional regions along the z-axis: 0~80 Å along the z-axis: Single-crystal 3C The SiC matrix region has a cuboid configuration with dimensions of 150 Å × 150 Å × 80 Å, and the upper surface is parallel to the x–y plane; Above 80 Å along the z-axis: the region of bilayer graphene layers, with a spacing of 3.35 Å between the bilayer graphene layers. The bilayer graphene layers are parallel to the x-axis and parallel to the single-crystal 3C along the armchair direction. The SiC substrate surface is arranged with a size of 160 Å × 160 Å, and the epitaxial layer covers the SiC substrate; The spherical diamond indenter adopts a diamond cubic structure, pressing down along the z-axis and achieving grinding motion along the x-axis.

[0040] Complete the single-crystal 3C process sequentially by region. Atom filling of SiC matrix and bilayer graphene; placing a spherical diamond indenter on a single-crystal 3C At a distance of 27 Å above the SiC matrix, the center of the sphere is relative to the single-crystal 3C. The center of the SiC matrix was offset by 30 Å along the positive x-axis to match the requirements of the nano-grinding process. Finally, a layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix was constructed for simulating the dynamic process of nano-indentation and grinding of graphene-SiC composite substrates.

[0041] The morphological changes of the system during the pressing process of the spherical diamond indenter output in this embodiment are as follows: Figure 5 As shown in (b), the indentation process is as follows: Figure 2 (c) and Figure 3 As shown in (c), the load-displacement curves of the spherical diamond indenter during the pressing and unloading processes are as follows: Figure 6 As shown in (c), it can be seen that both single-layer and double-layer graphene fractured during the compression process of the spherical graphene under the diamond indenter. Single-layer graphene significantly enhanced the pressure during the compression process: the downward pressure on the indenter increased from approximately 800 nN on the bare SiC surface to approximately 1200 nN; while double-layer graphene fractured during the compression process and failed to provide greater enhancement.

[0042] Example 3 Based on molecular dynamics simulation of the dynamic process of indentation and grinding on the surface of the three-layer graphene-SiC composite substrate, the difference from Example 1 is that step 1.2 (constructing a layered atomic model of diamond indenter / graphene layer / single crystal SiC substrate) is different, while the other steps are the same.

[0043] The specific steps for constructing a layered atomic model of a diamond indenter / graphene layer / single-crystal SiC matrix are as follows: Within the established coordinate system and simulation box, divide the functional regions along the z-axis: 0~80 Å along the z-axis: Single-crystal 3C The SiC matrix region has a cuboid configuration with dimensions of 150 Å × 150 Å × 80 Å, and the upper surface is parallel to the x–y plane; Above 80 Å along the z-axis: a region with three graphene layers, the spacing between the three graphene layers being 3.35 Å, and the three graphene layers being parallel to the x-axis and parallel to the single-crystal 3C along the armchair direction. The SiC substrate surface is arranged with a size of 160 Å × 160 Å, and the epitaxial layer covers the SiC substrate; The spherical diamond indenter adopts a diamond cubic structure, pressing down along the z-axis and achieving grinding motion along the x-axis.

[0044] Complete the single-crystal 3C process sequentially by region. Atom filling of SiC matrix and three-layer graphene; placing a spherical diamond indenter on a single-crystal 3C substrate. At a distance of 27 Å above the SiC matrix, the center of the sphere is relative to the single-crystal 3C. The center of the SiC matrix was offset by 30 Å along the positive x-axis to match the requirements of the nano-grinding process. Finally, a layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix was constructed for simulating the dynamic process of nano-indentation and grinding of graphene-SiC composite substrates.

[0045] The morphological changes of the system during the pressing process of the spherical diamond indenter output in this embodiment are as follows: Figure 5 As shown in (c), the indentation process is as follows: Figure 2 (d) and Figure 3 As shown in (d), the load-displacement curves of the spherical diamond indenter during the pressing and unloading processes are as follows: Figure 6 As shown in (d), comparing the morphological changes during the indentation process of spherical diamond, there is no significant difference in the influence of three-layer graphene on the surface morphology of single-layer and double-layer graphene. However, according to the indenter load-displacement curve, the force on the spherical diamond indenter is significantly enhanced when it contacts the top layer of three-layer graphene; but after the top layer of graphene breaks, the load on the indenter is not significantly different from that of double-layer graphene.

[0046] Comparative Example 1 Based on molecular dynamics simulation of the dynamic process of pressing and grinding on the surface of bare SiC substrate, the difference from Example 1 is that it does not contain a graphene layer.

[0047] I. Constructing a layered atomic model of a diamond indenter / single-crystal SiC matrix 1. Parameter settings A 3D model was constructed using LAMMPS software, employing metal units and atomic types. A standard Cartesian coordinate system was established, with the geometric center of the lower surface of the single-crystal SiC substrate as the origin. The x and y axes of the simulation box correspond to the in-plane directions of the crystal plane, using periodic (p) boundary conditions. The z-axis, perpendicular to the surface of the single-crystal SiC substrate, represents the direction of interlayer stacking, indenter loading, and grinding feed, using fixed (f) boundary conditions. Model geometry and lattice parameters were set based on measured values: the SiC substrate was a 3C-SiC cubic lattice (lattice constant 4.36 Å), and the spherical diamond indenter had a diamond cubic crystal structure (lattice constant 3.57 Å). The simulation box dimensions were 150 Å × 150 Å × 110 Å; the radius, indentation speed, and grinding steps of the spherical diamond indenter were set according to the process parameters. The simulation temperature was set to 293 K, the relaxation steps to 200,000, and the time step to 0.5 fs.

[0048] 2. Constructing a layered atomic model of a diamond indenter / single-crystal SiC matrix Within the established coordinate system and simulation box, divide the functional regions along the z-axis: 0~80 Å along the z-axis: Single-crystal 3C The SiC matrix region has a cuboid configuration with dimensions of 150 Å × 150 Å × 80 Å, and the upper surface is parallel to the x–y plane; The spherical diamond indenter adopts a diamond cubic structure, pressing down along the z-axis and achieving grinding motion along the x-axis.

[0049] Complete single-crystal 3C After atomic filling of the SiC matrix, a spherical diamond indenter is placed in a single-crystal 3C matrix. At a distance of 27 Å above the SiC matrix, the center of the sphere is relative to the single-crystal 3C. The center of the SiC matrix was offset by 30 Å along the positive x-axis to match the requirements of the nano-grinding process. Finally, a layered atomic model of the diamond indenter / single-crystal SiC matrix was constructed for simulating the dynamic processes of nano-indentation and grinding.

[0050] II. Selection of Potential Function 1. Define the mass parameters of each atom in the layered atomic model of diamond indenter / single-crystal SiC matrix: the mass of C atom is 12.01, and the mass of Si atom is 28.09; 2. Precisely select and set the interaction potential between each atom: Single-crystal 3C The interatomic interactions within the SiC matrix are described using the SiC Tersoff potential function provided by LAMMPS; spherical diamond indenter and single-crystal 3C The interatomic interactions between SiC matrices are described using Lennard-Jones potential functions. The potential function parameters for Si-C atom pairs are ε = 0.0089092 eV and σ = 3.6286 Å, and for CC atom pairs are ε = 0.0045532 eV and σ = 3.4309 Å. The cutoff radius for all Lennard-Jones potential functions is uniformly set to 10.5 Å to avoid interference from long-range interatomic interactions. 3. Output the layered atomic model configuration of the diamond indenter / single-crystal SiC matrix and generate LAMMPS data files to provide basic data support for subsequent simulations.

[0051] III. Defining Model Boundaries and Temperature Control Layers After describing the potential function, the single-crystal 3C in the layered atomic model of diamond indenter / single-crystal SiC matrix was analyzed. The SiC matrix is ​​defined by a fixed layer, a temperature-controlled layer, and a Newtonian layer. The fixed layer has a 10 Å thickness and its atoms are set to a fixed state. Above the fixed layer, a 40 Å thick temperature-controlled layer is continuously constructed to maintain a constant atomic temperature. Above the temperature-controlled layer, a 30 Å thick Newtonian layer is continuously constructed. The atomic temperature of the Newtonian layer varies with the motion of the spherical diamond indenter and the interatomic interaction potential function. A single-crystal SiC matrix is ​​also defined. Intra-atomic grouping within the SiC matrix.

[0052] IV. Model Relaxation and Energy Steady-State Optimization 1. Relaxation treatment: In the layered atomic model of the diamond indenter / single-crystal SiC matrix, the spherical diamond indenter and the single-crystal 3C matrix are relaxed. The initial velocity of the atoms in the fixed layer of the SiC matrix was set to 0, and the force on this group of atoms was defined as zero using the fix setforce command, thus completing the fixation of the atoms; then, the velocity parameters were set according to the simulation requirements, and the single-crystal 3C was defined using the velocity create command. The initial velocity of the non-fixed atomic group in the SiC matrix is ​​set to Gaussian distribution. The temperature parameter in the command is set to 293 K and the random number is set to 12345 to generate a simulated temperature of 293 K. Then, the atomic group is run for 10 ps under the NPT ensemble to achieve relaxation of the diamond indenter / single crystal SiC matrix layered atomic model and ensure that the system reaches a stable state. 2. Energy Minimization Process: After relaxation, the conjugate gradient method (cg) is used to minimize the energy of the diamond indenter / single-crystal SiC matrix layered atomic model. The key parameters are set as follows: Etot (total energy of the system during the simulation, in eV), Ftol (force tolerance during energy minimization, in eV / Angstrom), Maxiter, and Maxeval are set to 1e-15, 1e-15, 5000, and 5000, respectively. After energy minimization, the energy-minimized diamond indenter / single-crystal SiC matrix layered atomic model is output.

[0053] V. Simulation of Dynamic Process of Grinding on Bare SiC Substrate 1. Setting the position parameters of the spherical diamond indenter: The total displacement of the spherical diamond indenter is set to 30 Å. This is because the initial displacement of the spherical diamond indenter is relative to the single-crystal 3C crystal. There is a 10 Å gap between the upper surfaces of the SiC matrix, so the total indentation depth of the spherical diamond indenter is 20 Å; the loading depth and speed of the spherical diamond indenter are set, where the indentation depth is determined by the function d(t) = 0.3 (Å / ps). The time step t(ps) varies linearly with time to define the position change of the spherical diamond indenter during uniform downward pressure in the z-direction. The fix move linear command is used to define the pressing and unloading processes of the spherical diamond indenter. The speed of the unloading process is the same as that of the loading process, 0.3 Å / ps, and the direction is vertically upward. The total number of unloading steps is equal to the total number of loading steps. The simulation time step is set to 0.001 ps. Based on this, the simulation step size for the pressing stage is adjusted to achieve indentation depths of 2 Å, 5 Å, and 8 Å on the substrate surface. 2. Calculation settings for relevant physical quantities: The `compute stress / atom` command is used to calculate atomic stress, based on virial stress (see the LAMMPS manual (https: / / docs.lammps.org / compute_stress_atom.html) for calculation methods); the `compute Voronoi / atom` command is used to calculate the Voronoi lattice volume, simultaneously defining the total atomic stress tensor, and the `compute temp` command is used to calculate atomic temperature (see the LAMMPS manual for calculation methods). https: / / docs.lammps.org / compute_temp.html )); 3. Load Calculation: The compute reduce command is used to perform force calculations on the atomic group of the spherical diamond indenter. The sum of the forces fx, fy, and fz of the spherical diamond indenter in the x, y, and z directions is calculated to obtain the load of the spherical diamond indenter in the three directions. 4. Data and morphology output during simulation: The fix ave / time command is used to output the load of the spherical diamond indenter at a frequency of once every 100 steps, and the dump command is used to output the morphological changes of the system during the compression process of the spherical diamond indenter at a frequency of once every 1000 steps. Figure 4 ); 5. Simulated loading control: The fix move linear command is used to complete the process of uniformly pressing down the spherical diamond indenter, holding the load at rest, and unloading the load at a uniform speed until the spherical diamond indenter returns to its initial height, thus completing the full loading-holding-unloading simulation. 6. Running the indentation process: The simulation steps are set to 150,000 steps to simulate the complete process of the spherical diamond indenter approaching and moving away from the substrate during nanoindentation. Figure 3 (a) 7. Run the grinding process: Use the fix move linear command to define the uniform motion of the spherical diamond indenter in the x direction. Simulate the grinding process of the bare SiC substrate surface by applying displacement in the x direction. Set the number of grinding process simulation steps to 200,000 steps to simulate the dynamic process of grinding.

[0054] VI. Results Output 1. Data Post-processing and Curve Plotting: Based on the output load and displacement data, plot the load-displacement curves of the spherical diamond indenter during the pressing and unloading processes. Figure 6 (a)); Simultaneously, the temperature and stress field changes during the grinding process of the spherical diamond indenter on the SiC substrate surface are obtained, generating temperature and stress distribution maps of SiC atoms (a) Figure 8 (a), (c) and (e)); 2. Microscopic Mechanism and Damage Analysis: Capture the formation process of microstructure and wear debris near SiC trenches, reveal the formation mechanism of graphene wrinkles and fractures through abrupt changes in cutting force, explain the graphene lubrication effect, and complete the identification and causal analysis of subsurface damage depth and phase transition region.

[0055] The results of comparing the surface morphology and internal stress distribution of bare SiC (Comparative Example 1) and graphene-SiC composite substrate (Example 1) after nano-grinding are as follows: Figure 9 As shown in Figure 10, the comparison results of surface morphology and internal stress distribution after nano-grinding at different indentation depths are shown in Figure 10. The load-displacement curves and corresponding model configurations are compared in the figure. Figure 11As shown, by comparing the morphological changes of bare SiC substrates and graphene-SiC composite substrates during the grinding process, it can be seen that graphene can significantly suppress the generation of grinding debris, thereby obtaining a more uniform surface. Furthermore, during SiC grinding, graphene can significantly reduce the stress in the grinding area, playing a role in stress dispersion. Load-displacement curves show that, at the same indentation depth, the presence of graphene increases the load between the indenter and the substrate surface; however, after graphene fractures, the load drops to a level similar to that of bare SiC.

[0056] Example 4: System based on molecular dynamics simulation of the dynamic processes of indentation and grinding on the surface of graphene-SiC composite substrate Example 4 of this invention is an example of the system provided by this invention for simulating the dynamic process of indentation and grinding on the surface of graphene-SiC composite substrate based on molecular dynamics. The system example includes: a potential function description model construction module, a hierarchical atomic model construction module, an indentation and grinding dynamic process simulation module, and a result output module.

[0057] The potential function description model construction module is used to select different potential functions to describe the interactions between atoms in the layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix, and obtain the potential function description model; The layered atomic model construction module is used to set boundaries and temperature-controlled layering of the potential function description model and relax it to the minimum energy to obtain an energy-steady layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix. The dynamic process simulation module for indentation and grinding is used to control the diamond indenter to press down along the direction perpendicular to the surface of the single crystal SiC substrate in the energy steady-state layered atomic model of diamond indenter / graphene layer / single crystal SiC substrate, and then move along the direction parallel to the surface of the single crystal SiC substrate and the plane of the graphene layer, respectively simulating the dynamic process of indentation and grinding on the surface of graphene-SiC composite substrate. The results output module is used to output simulation results and analyze the mechanical behavior of the graphene-SiC composite substrate surface during the dynamic process of indentation and grinding.

[0058] It is understood that the system provided by this invention, which simulates the dynamic process of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics, corresponds to the method provided in the foregoing embodiments. The relevant technical features of the system can be referenced to the relevant technical features of the method, which specifically includes the following steps: Different potential functions were selected to describe the interactions between atoms in the layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix, respectively, and potential function description models were obtained. By setting boundaries and temperature-controlled stratification for the potential function description model and relaxing it to the minimum energy, a layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix with stable energy is obtained. In the energy-steady diamond indenter / graphene layer / single-crystal SiC matrix layered atomic model, the diamond indenter is controlled to press down in a direction perpendicular to the surface of the single-crystal SiC matrix, and then move in a direction parallel to the surface of the single-crystal SiC matrix and the plane of the graphene layer, respectively simulating the dynamic process of indentation and grinding on the surface of the graphene-SiC composite substrate. Output simulation results to analyze the mechanical behavior of the graphene-SiC composite substrate surface during indentation and grinding dynamic processes.

[0059] Example 5 Electronic device This embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the steps of the method based on molecular dynamics simulation of the dynamic process of indentation and grinding of the graphene-SiC composite substrate surface.

[0060] The method for simulating the dynamic processes of indentation and grinding on the surface of graphene-SiC composite substrates based on molecular dynamics includes the following steps: Different potential functions were selected to describe the interactions between atoms in the layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix, respectively, and potential function description models were obtained. By setting boundaries and temperature-controlled stratification for the potential function description model and relaxing it to the minimum energy, a layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix with stable energy is obtained. In the energy-steady diamond indenter / graphene layer / single-crystal SiC matrix layered atomic model, the diamond indenter is controlled to press down in a direction perpendicular to the surface of the single-crystal SiC matrix, and then move in a direction parallel to the surface of the single-crystal SiC matrix and the plane of the graphene layer, respectively simulating the dynamic process of indentation and grinding on the surface of the graphene-SiC composite substrate. Output simulation results to analyze the mechanical behavior of the graphene-SiC composite substrate surface during indentation and grinding dynamic processes.

[0061] Example 6: Computer-readable storage medium This embodiment provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the steps of the method based on molecular dynamics simulation of the dynamic process of indentation and grinding on the surface of a graphene-SiC composite substrate.

[0062] The method for simulating the dynamic processes of indentation and grinding on the surface of graphene-SiC composite substrates based on molecular dynamics includes the following steps: Different potential functions were selected to describe the interactions between atoms in the layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix, respectively, and potential function description models were obtained. By setting boundaries and temperature-controlled stratification for the potential function description model and relaxing it to the minimum energy, a layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix with stable energy is obtained. In the energy-steady diamond indenter / graphene layer / single-crystal SiC matrix layered atomic model, the diamond indenter is controlled to press down in a direction perpendicular to the surface of the single-crystal SiC matrix, and then move in a direction parallel to the surface of the single-crystal SiC matrix and the plane of the graphene layer, respectively simulating the dynamic process of indentation and grinding on the surface of the graphene-SiC composite substrate. Output simulation results to analyze the mechanical behavior of the graphene-SiC composite substrate surface during indentation and grinding dynamic processes.

[0063] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0064] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0065] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0066] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

[0068] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A method based on molecular dynamics simulation of the dynamic processes of indentation and grinding on the surface of a graphene-SiC composite substrate, defining the integrated heterogeneous substrate material formed by in-situ epitaxial composite graphene layers on the surface of a single-crystal SiC substrate as a graphene-SiC composite substrate, characterized in that... Includes the following steps: Different potential functions were selected to describe the interactions between atoms in the layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix, respectively, and potential function description models were obtained. By setting boundaries and temperature-controlled stratification for the potential function description model and relaxing it to the minimum energy, a layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix with stable energy is obtained. In the energy-steady diamond indenter / graphene layer / single-crystal SiC matrix layered atomic model, the diamond indenter is controlled to press down in a direction perpendicular to the surface of the single-crystal SiC matrix, and then move in a direction parallel to the surface of the single-crystal SiC matrix and the plane of the graphene layer, respectively simulating the dynamic process of indentation and grinding on the surface of the graphene-SiC composite substrate. The simulation results are output to analyze the mechanical behavior of the graphene-SiC composite substrate surface during the dynamic processes of indentation and grinding.

2. The method for simulating the dynamic process of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics, as described in claim 1, is characterized in that... The method for constructing the layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix is ​​as follows: using LAMMPS software, with the in-plane direction of the crystal as the x-axis and y-axis and a periodic boundary, and the direction perpendicular to the surface of the single-crystal SiC matrix as the z-axis and a fixed boundary condition, with the geometric center of the lower surface of the single-crystal SiC matrix as the origin of the coordinate system, the single-crystal SiC matrix is ​​constructed in the z-axis direction, a graphene layer is constructed on top of the single-crystal SiC matrix, and the diamond indenter is placed on top of the graphene layer to obtain the layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix.

3. The method for simulating the dynamic process of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics, as described in claim 2, is characterized in that... The size of the single-crystal SiC substrate is 150 Å × 150 Å × 80 Å, and the size of the graphene layer is 160 Å × 160 Å.

4. The method for simulating the dynamic process of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics, as described in claim 2, is characterized in that... SiC uses a 3C-SiC cubic lattice with a lattice constant of 4.36 Å; the diamond indenter uses a diamond cubic crystal structure with a lattice constant of 3.57 Å; and graphene uses a hexagonal lattice with a lattice constant of 2.45 Å.

5. The method for simulating the dynamic process of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics, as described in claim 1, is characterized in that... The steps for selecting the potential function are as follows: the interaction between atoms inside the single-crystal SiC matrix is ​​described by the SiC.Tersoff potential function, the interaction between carbon atoms inside the graphene layer is described by the CH.airebo potential function, and the interatomic interactions between the graphene layer and the diamond indenter, between the graphene layer and the single-crystal SiC matrix, and between the diamond indenter and the single-crystal SiC matrix are all described by the Lennard-Jones potential function.

6. The method for simulating the dynamic process of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics, as described in claim 1, is characterized in that... The temperature-controlled layering steps are as follows: In the layered atomic model of diamond indenter / graphene layer / single-crystal SiC matrix, a fixed layer, a temperature-controlled layer, and a Newton layer are defined for the single-crystal SiC matrix. The atoms in the fixed layer are set to a fixed state. A temperature-controlled layer with a constant atomic temperature is continuously constructed above the fixed layer. A Newton layer is continuously constructed above the temperature-controlled layer. The atomic temperature of the Newton layer changes with the indenter movement and the interatomic interaction potential function. At the same time, the atomic groupings in the single-crystal SiC matrix and the fixed boundary regions of the graphene layer are defined. The graphene layer is divided into graphene fixed atom groups, and the remaining graphene layer atoms are assigned to Newton groups.

7. The method for simulating the dynamic process of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics, as described in claim 1, is characterized in that... The output simulation results include load-displacement curves of the diamond indenter during the pressing and unloading processes, and changes in temperature and stress field during the grinding process of the diamond indenter on the graphene-SiC composite substrate.

8. A system based on molecular dynamics simulation of the dynamic processes of indentation and grinding on the surface of a graphene-SiC composite substrate, characterized in that, include: The potential function description model construction module is used to select different potential functions to describe the interactions between atoms in the layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix, and obtain the potential function description model; The layered atomic model construction module is used to set boundaries and temperature-controlled layering of the potential function description model and relax it to the minimum energy to obtain an energy-steady layered atomic model of diamond indenter / graphene layer / single crystal SiC matrix. The dynamic process simulation module for indentation and grinding is used to control the diamond indenter to press down along the direction perpendicular to the surface of the single crystal SiC substrate in the energy steady-state layered atomic model of diamond indenter / graphene layer / single crystal SiC substrate, and then move along the direction parallel to the surface of the single crystal SiC substrate and the plane of the graphene layer, respectively simulating the dynamic process of indentation and grinding on the surface of graphene-SiC composite substrate. The results output module is used to output simulation results and analyze the mechanical behavior of the graphene-SiC composite substrate surface during the dynamic process of indentation and grinding.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method for simulating the dynamic process of indentation and grinding on the surface of a graphene-SiC composite substrate based on molecular dynamics simulation as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for simulating the dynamic process of indentation and grinding of the graphene-SiC composite substrate surface based on molecular dynamics simulation as described in any one of claims 1 to 7.

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