3C-SiC crack propagation and mechanical property prediction method

Abstract

The invention discloses a 3C-SiC crack propagation and mechanical property prediction method, and belongs to the technical field of material science and computer simulation, and the method comprises the following steps: S1, constructing a polycrystalline 3C-SiC atomic model, S2, simulating the crack propagation behavior of the polycrystalline 3C-SiC atomic model, S3, analyzing the microstructure evolution of the polycrystalline 3C-SiC by using OVITO software, S4, constructing a fracture characteristic evaluation model, and S5, evaluating the fracture characteristics of the polycrystalline 3C-SiC. S5, a mechanical property prediction database based on molecular dynamics is constructed, and visual analysis and quantitative prediction of the crack propagation behavior of the 3C-SiC are achieved. The method is used for researching the crack propagation behavior of the polycrystalline 3C-SiC under different working conditions, and prediction of the fracture toughness and the failure mode of a material is achieved.

Description

Technical Field

[0001] The present invention relates to the fields of materials science and computer simulation technology, and particularly relates to a method for predicting crack propagation and mechanical properties of 3C-SiC. Background Art

[0002] 3C-SiC (cubic silicon carbide) is an advanced ceramic material with excellent mechanical properties, thermal stability and corrosion resistance, and has wide applications in the fields of aerospace, semiconductor devices, nuclear energy systems and high-temperature structural materials. Due to its covalent-bonded crystal structure, 3C-SiC exhibits high hardness, high elastic modulus, low thermal expansion coefficient and excellent high-temperature resistance, and is thus considered an ideal material for applications in extreme environments. However, 3C-SiC materials also pose certain challenges in terms of mechanical properties, especially in crack propagation and fracture toughness. Due to its brittle fracture characteristics, it is prone to failure when subjected to external loads. Therefore, accurately predicting the crack propagation behavior and mechanical properties of 3C-SiC is crucial for optimizing material design and improving its engineering application capabilities.

[0003] In recent years, molecular dynamics (MD) simulation, as a powerful computational tool, has been widely used in studying the mechanical behavior of nanoscale materials. However, existing research mainly focuses on the brittle fracture characteristics of ideal single-crystal SiC, and there are still few systematic studies on the crack propagation behavior of polycrystalline 3C-SiC, the influence of grain size on the crack propagation path, and the interaction between the crack tip and grain boundaries. In addition, changes in external temperature and strain rate also have an important impact on crack propagation behavior. In a high-temperature environment, the thermal vibration inside the material is enhanced, which may lead to the instability of local bonding and thus accelerate crack propagation. Under high strain rate conditions, the crack propagation mode may change from brittle fracture to quasi-plastic failure.

[0004] Based on this, the present invention provides a method for predicting crack propagation and mechanical properties of 3C-SiC Summary of the Invention

[0005] The object of the present invention is to provide a method for predicting crack propagation and mechanical properties of 3C-SiC. The present invention combines Voronoi polycrystalline modeling technology, LAMMPS molecular dynamics simulation, radial distribution function (RDF) analysis, stress cloud diagram and dislocation density calculation to establish a correlation model between crack propagation and mechanical properties, which is used to study the crack propagation behavior of polycrystalline 3C-SiC under different working conditions, and realizes the prediction of material fracture toughness and failure mode.

[0006] To achieve the above object, the present invention provides a method for predicting crack propagation and mechanical properties of 3C-SiC, including the following steps:

[0007] S1. Construct a polycrystalline 3C-SiC atomic model;

[0008] S2. Simulate the crack propagation behavior of the polycrystalline 3C-SiC atomic model;

[0009] S3. After obtaining the crack propagation behavior, use the OVITO software to analyze the microstructure evolution of polycrystalline 3C-SiC;

[0010] S4. After completing the analysis, construct a fracture property evaluation model;

[0011] S5. According to the fracture property evaluation model in S4, construct a molecular dynamics-based mechanical property prediction database to realize the visual analysis and quantitative prediction of the crack propagation behavior of 3C-SiC.

[0012] Preferably, the process of constructing the polycrystalline 3C-SiC atomic model in S1 is as follows:

[0013] S11. Obtain the crystallographic information file of cubic silicon carbide through the Next Generation Materials Program database;

[0014] S12. Use the Atomsk software to execute the format conversion command to convert the crystallographic information file of cubic silicon carbide into the LAMMPS data format;

[0015] S13. After converting the crystallographic information file of cubic silicon carbide into the LAMMPS data format, create a grain distribution configuration file, define the simulation box, and specify the random grain distribution seed number;

[0016] S14. Execute the command through the --polycrystal mode of Atomsk to generate a polycrystalline structure model;

[0017] S15. Use the read function of the ASE library to read the basic polycrystalline structure model, and create models with different crack lengths in the central region of the (001) crystal plane within the range of [10, 20, 30, 40, 50] angstroms through the custom function add_crack;

[0018] S16. Use the write function of ASE to output the LAMMPS format models with different crack lengths;

[0019] S17. Generate a polycrystalline 3C-SiC atomic model with a complete crack series in the range of 0 angstroms to 50 angstroms through parametric control.

[0020] Preferably, the process of simulating the crack propagation behavior of the polycrystalline 3C-SiC atomic model in S2 is as follows:

[0021] S21. Establish a temperature control system using the Langevin heat bath algorithm to build a thermodynamic environment module;

[0022] S22. Set the temperature of the thermodynamic environment module between 300 K and 1500 K, and at the same time set the time step to 1 fs. Apply tensile loading to the polycrystalline 3C-SiC atomic model obtained in S1, and then output the trajectory file.

[0023] S23. Configure the dynamic loading control module, and realize mechanical loading through the coupling of the strain rate control model and the Verlet integration algorithm. Set the strain rate range to 10 9 to 10 11 s -1 , with the loading direction being

[100] . After applying tensile loading again, output the trajectory file to obtain the crack propagation behavior under different temperature, strain rate, and crack size conditions.

[0024] Preferably, the process of analyzing the microstructure evolution of polycrystalline 3C-SiC in S3 is as follows:

[0025] S31. Integrate the defect evolution analysis module, and use the IDS topology command of the OVITO visualization platform to identify grain boundary atoms and simultaneously use the DXA algorithm to analyze the trajectory file to realize dynamic defect tracking.

[0026] S32. After completing the dynamic defect tracking, rely on the quantitative analysis method of the radial distribution function to analyze the dynamic process of grain boundary disordering through the peak position shift and intensity attenuation of characteristic peaks.

[0027] S33. Then use the stress cloud Figure 3 3D reconstruction technology to observe the dynamic distribution characteristics of the stress field and realize the atomic-scale dynamic capture of the crack propagation path in combination with the stress cloud diagram.

[0028] Preferably, the stress cloud diagram mentioned in S33 calculates the stress distribution at the crack tip, identifies the crack propagation mode, and analyzes the microscopic mechanism of the crack-grain boundary interaction in combination with the dislocation density statistics.

[0029] Preferably, the fracture characteristic evaluation model mentioned in S4 includes an energy dissipation analysis model, a microstructure correlation model, and a preferred path extension prediction algorithm.

[0030] Preferably, the process of constructing the fracture characteristic evaluation model in S4 is as follows:

[0031] S41. Establish an energy dissipation analysis model based on the difference in energy release methods during the crack propagation process.

[0032] S42. Establish a microstructure correlation model based on the quantitative relationship between grain size, crack length, and fracture toughness.

[0033] S43. Establish a preferred path extension prediction algorithm based on the analysis of crack propagation from the structure evolution diagram.

[0034] Preferably, the difference in energy release mode in S41 is calculated by using the Griffith criterion for predicting the effects of different crack sizes and grain structures on the toughness of 3C-SiC materials in combination with a modified fracture mechanics model.

[0035] Preferably, the mechanical property prediction database in S5 is constructed based on multi-field coupled molecular dynamics simulation data.

[0036] Therefore, the method for predicting 3C-SiC crack propagation and mechanical properties using the above structure has the following advantages:

[0037] 1. The Voronoi method is used to construct a polycrystalline 3C-SiC model to simulate the influence of different grain sizes and grain boundary structures on crack propagation, and an initial crack is introduced to study the stress concentration at the crack tip and the grain boundary interaction mechanism;

[0038] 2. Through LAMMPS molecular dynamics simulation, the crack propagation behavior is analyzed under different strain rates and temperature conditions;

[0039] 3. Combining the calculation of radial distribution function, stress nephogram and dislocation density, the shielding and dissipation effects of grain boundaries on crack propagation are revealed, and the microscopic regulation mechanism of fracture toughness is clarified;

[0040] 4. Based on the simulation data, a crack propagation prediction database is constructed to realize the quantitative prediction and visualization analysis of the mechanical properties of polycrystalline 3C-SiC;

[0041] 5. The service reliability of the model in extreme environments is improved, and it is applicable to high-performance application scenarios such as high-temperature structural materials, semiconductor components and protective armors.

[0042] The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is the microstructure diagram of polycrystalline 3C-SiC of a method for predicting 3C-SiC crack propagation and mechanical properties of the present invention;

[0044] Figure 2 It is the change diagram of the grain boundary atom percentage of random polycrystalline 3C-SiC of a method for predicting 3C-SiC crack propagation and mechanical properties of the present invention with the average grain size;

[0045] Figure 3 It is the coupling relationship diagram of Young's modulus (a), failure stress (b) and failure strain (c) of polycrystalline 3C-SiC of a method for predicting 3C-SiC crack propagation and mechanical properties of the present invention with the grain size and the initial crack length;

[0046] Figure 4 The initial crack length of a method for predicting crack propagation and mechanical properties of 3C-SiC according to the present invention is Strain rate sensitivity diagram of polycrystalline 3C-SiC with a grain size of 10 nm;

[0047] Figure 5 The initial crack length of a method for predicting crack propagation and mechanical properties of 3C-SiC according to the present invention is Relationship diagram of the total length of dislocation lines (a) and dislocation density (b) of polycrystalline 3C-SiC with a grain size of 4 nm varying with temperature;

[0048] Figure 6 The initial crack length of a method for predicting crack propagation and mechanical properties of 3C-SiC according to the present invention is Variation diagram of polycrystalline materials with a grain size of 6 nm at different temperatures. Detailed implementation manners

[0049] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0050] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0051] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0052] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0053] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and defined, the terms "set", "installed", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0054] The following will describe in detail some embodiments of the present invention with reference to the accompanying drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0055] Embodiment 1

[0056] As Figures 1-6 shown, a method for predicting crack propagation and mechanical properties of 3C-SiC of the present invention includes the following steps:

[0057] S1. Construct a polycrystalline 3C-SiC atomic model;

[0058] S11. Obtain the crystallographic information file of cubic silicon carbide through the Next Generation Materials Project database;

[0059] S12. Use the Atomsk software to execute the format conversion command to convert the crystallographic information file of cubic silicon carbide into the LAMMPS data format;

[0060] S13. After converting the crystallographic information file of cubic silicon carbide into the LAMMPS data format, create a grain distribution configuration file, define the simulation box, and specify the random grain distribution seed number;

[0061] S14. Execute the command through the --polycrystal mode of Atomsk to generate a polycrystalline structure model;

[0062] S15. Use the read function of the ASE library to read the basic polycrystalline structure model, and create models with different crack lengths in the central region of the (001) crystal plane within the range of [10, 20, 30, 40, 50] angstroms through the custom function add_crack;

[0063] S16. Use the write function of ASE to output the LAMMPS format models with different crack lengths;

[0064] S17. Generate a polycrystalline 3C-SiC atomic model including a complete crack series in the range of 0 angstroms to 50 angstroms through parametric control.

[0065] S2. Simulate the crack propagation behavior of the polycrystalline 3C-SiC atomic model;

[0066] S21. Establish a temperature control system using the Langevin heat bath algorithm to build a thermodynamic environment module;

[0067] S22. Set the temperature of the thermodynamic environment module between 300K and 1500K, and at the same time set the time step to 1fs. Stretch and load the polycrystalline 3C-SiC atomic model obtained in S1, and then output the trajectory file;

[0068] S23. Configure a dynamic loading control module to achieve mechanical loading through the coupling of the strain rate control model and the Verlet integration algorithm. Set the strain rate range to 109 to 1011 s-1, and the loading direction to

[100] . After stretching and loading again, output the trajectory file to obtain the crack propagation behavior under different temperatures, strain rates, and crack sizes.

[0069] S3. After obtaining the crack propagation behavior, use OVITO software to analyze the microstructure evolution of polycrystalline 3C-SiC;

[0070] S31. Integrate the defect evolution analysis module, and use the IDS topology command of the OVITO visualization platform to identify grain boundary atoms and use the DXA algorithm to analyze the trajectory file to achieve dynamic defect tracking;

[0071] S32. After completing the dynamic defect tracking, rely on the quantitative analysis method of the radial distribution function to analyze the disordering kinetic process of the grain boundary through the characteristic peak position shift and intensity attenuation;

[0072] S33. Then use the stress cloud Figure 3 three-dimensional reconstruction technology to calculate the stress distribution at the crack tip, identify the crack propagation mode, and combine the dislocation density statistics to analyze the microscopic mechanism of the crack-grain boundary interaction, and observe the dynamic distribution characteristics of the stress field and combine the stress cloud diagram to achieve atomic-scale dynamic capture of the crack propagation path.

[0073] S4. After completing the analysis, construct a fracture characteristic evaluation model, including an energy dissipation analysis model, a microstructure correlation model, and a preferred path extension prediction algorithm;

[0074] S41. Establish an energy dissipation analysis model based on the difference in energy release methods during crack propagation. The difference in energy release methods is calculated using the Griffith criterion for predicting the influence of different crack sizes and grain structures on the toughness of 3C-SiC materials combined with a modified fracture mechanics model;

[0075] S42. Establish a microstructure correlation model based on the quantitative relationship between grain size, crack length, and fracture toughness;

[0076] S43. Establish a preferred path extension prediction algorithm based on crack propagation analysis using a structure evolution diagram.

[0077] S5. According to the fracture property evaluation model in S4, construct a mechanical property prediction database based on molecular dynamics to achieve visual analysis and quantitative prediction of the crack propagation behavior of 3C-SiC.

[0078] The stress nephogram mentioned in S33 calculates the stress distribution at the crack tip, identifies the crack propagation mode, and analyzes the microscopic mechanism of crack-grain boundary interaction by combining dislocation density statistics.

[0079] To verify the effectiveness of the method of the present invention, multiple experiments were designed for different experimental parameters to study the effects of factors such as different grain sizes, crack lengths, temperatures, and strain rates on the crack propagation behavior and mechanical properties of 3C-SiC.

[0080] Study on crack propagation behavior at fixed temperature and strain rate;

[0081] A polycrystalline model of 3C-SiC with an average grain size of 6 nm was constructed, and a prefabricated crack with a length of was introduced inside it. To accurately describe the interaction between Si-C atoms, the Tersoff potential function was used for molecular dynamics simulation. During the simulation process, the ambient temperature was maintained at 300 K, and a strain rate of 1×10 9 / s was used to apply uniaxial tensile loading to the model, and the LAMMPS software was used for large-scale parallel computing.

[0082] Under these temperature and strain rate conditions, crack propagation mainly occurs along the grain boundaries, and the stress concentration phenomenon at the crack tip is relatively significant. Calculations show that the crack propagation speed and path are greatly affected by the grain size. When the crack tip approaches the grain boundary, due to the disordered atomic arrangement in the grain boundary region, the crack propagation path is hindered to a certain extent, resulting in a slowdown in the crack propagation speed. However, when the crack is inside the grain, the crack propagation path is relatively straight and the propagation rate is faster.

[0083] Further analysis of the stress-strain curve during crack propagation reveals that when the crack initiates, the stress of the sample drops rapidly, indicating that the material enters the failure stage. At the same time, radial distribution function (RDF) analysis shows that during crack propagation, the fracture of Si-C bonds mainly occurs in the crack tip region, while the region far from the crack still maintains a complete lattice structure. This indicates that under the loading conditions of 300 K and 1×10 9 / s, the dominant mechanism of crack propagation is brittle fracture along the grain boundaries, and the stress concentration effect at the crack tip is the main factor leading to the accelerated crack propagation.

[0084] Example 2

[0085] Effect of Temperature on Crack Propagation Behavior

[0086] This example mainly studies the effect of temperature on crack propagation behavior. To explore the influence mechanism of temperature, a polycrystalline 3C-SiC model with a grain size of 8 nm and a crack length of was constructed and molecular dynamics simulations were carried out under four temperature conditions of 600 K, 900 K, 1200 K, and 1500 K. During the simulation process, uniaxial tensile loading was applied to the material at a fixed strain rate of 1×109 / s, and the changes in crack propagation modes at different temperatures were analyzed.

[0087] The simulation results show that temperature has a significant effect on the crack propagation path and fracture mode. At a lower temperature (600 K), crack propagation mainly occurs along the grain boundaries, and the crack path is relatively straight, indicating obvious brittle fracture characteristics of the material. However, at higher temperatures (1200 K and above), the crack propagation mode changes, and the crack no longer strictly propagates along the grain boundaries but gradually penetrates into the grain interior. At the same time, the crack propagation speed under high-temperature conditions increases significantly, indicating that the increase in temperature reduces the crack resistance of the material.

[0088] By calculating the stress field distribution at the crack tip, it is found that the stress concentration effect at the crack tip weakens under high-temperature conditions, and the crack propagation direction becomes more irregular. In addition, through the analysis of the radial distribution function (RDF), it is found that the increase in temperature leads to enhanced thermal vibration of the Si-C bonds, resulting in a decrease in the short-range order of the material, which in turn affects the crack propagation path. In summary, this example shows that temperature has an important regulatory effect on crack propagation behavior. The crack propagation mode is more complex under high-temperature conditions, and the brittle fracture tendency of the material is alleviated.

[0089] Example 3

[0090] Effect of Strain Rate on Crack Propagation Behavior:

[0091] This example mainly studies the crack propagation law under different strain rate conditions. To analyze the effect of strain rate on crack propagation, a polycrystalline 3C-SiC model with an average grain size of 4 nm was constructed, and uniaxial tensile tests were carried out under four strain rate conditions of 1×109 / s, 5×109 / s, 1×1010 / s, and 1×1011 / s.

[0092] The simulation results show that the strain rate has an important effect on the crack propagation path and fracture mode. Under low strain rate (1×109 / s) conditions, the crack propagation mode is mainly brittle fracture along the grain boundaries, the crack path is relatively regular, and the propagation speed is slow. However, under high strain rate (1×1011 / s) conditions, the degree of local plastic deformation at the crack tip increases, the crack propagation path becomes more complex, and the crack shows bifurcation phenomena in some regions.

[0093] The calculation results show that the stress concentration effect at the crack tip is reduced at higher strain rates, and the crack propagation mode is more dependent on local plastic deformation. At the same time, the crack propagation speed decreases significantly with the increase of strain rate, indicating that high strain rates can effectively delay crack propagation and improve the fracture resistance of materials. This phenomenon shows that the strain rate is an important factor affecting the fracture toughness of 3C-SiC.

[0094] Example 4

[0095] Effect of crack length on fracture toughness

[0096] This example explores the effect of the initial crack length on the fracture toughness of the material. A polycrystalline model of 3C-SiC with a fixed grain size (6 nm) is used, and different initial crack lengths are set. Tensile simulations are carried out under the conditions of a fixed temperature of 300 K and a fixed strain rate of 1×109 / s.

[0097] The simulation results show that the crack length has an important influence on the ultimate strength and fracture strain of the material. With the increase of the crack length, the fracture toughness of the material decreases significantly, and the failure stress of the long crack system decreases significantly. In addition, when the crack is short the crack propagation speed is slow, while when the crack is long the crack propagation speed is significantly accelerated, and the propagation path is more likely to follow the grain boundaries.

[0098] By calculating the energy release rate at the crack tip, it is found that when the crack length is long, the local stress concentration degree at the crack tip is higher, making the crack easier to propagate. The radial distribution function (RDF) analysis shows that the proportion of broken Si-C bonds in the long crack system is higher, further verifying the influence of crack length on fracture toughness.

[0099] Example 5

[0100] Coupling effect of temperature and strain rate

[0101] This example studies the synergistic effect of temperature and strain rate on crack propagation behavior. A polycrystalline model of 3C-SiC with a grain size of 6 nm and a crack length of is constructed, and simulations are carried out at five temperatures (300 K, 600 K, 900 K, 1200 K, 1500 K) and five strain rates (1×109 / s to 1×1011 / s).

[0102] The research findings show that under extreme high-temperature and high-strain-rate conditions, the crack propagation mode changes significantly, dynamic recrystallization occurs within the material, and certain characteristics of quasi-plastic deformation are exhibited. At the same time, the crack path becomes complex, and nano-sized grains are generated in local areas, indicating that dynamic strengthening phenomenon occurs in the material under high temperature and high strain rate.

[0103] Therefore, the present invention adopts a method for predicting crack propagation and mechanical properties of 3C-SiC with the above structure. The Voronoi method is used to construct a polycrystalline 3C-SiC model to simulate the influence of different grain sizes and grain boundary structures on crack propagation, and an initial crack is introduced to study the stress concentration at the crack tip and the mechanism of grain boundary interaction. Through LAMMPS molecular dynamics simulation, the crack propagation behavior is analyzed under different strain rates and temperature conditions, and combined with the calculation of the radial distribution function, stress cloud diagram and dislocation density, the shielding and dissipation effects of grain boundaries on crack propagation are revealed, and the microscopic regulation mechanism of fracture toughness is clarified. Then, based on the simulation data, a crack propagation prediction database is constructed to realize the quantitative prediction and visualization analysis of the mechanical properties of polycrystalline 3C-SiC, improve the service reliability of the model in extreme environments, and is applicable to high-performance application scenarios such as high-temperature resistant structural materials, semiconductor components and protective armor.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for predicting crack propagation and mechanical properties of 3C-SiC, characterized in that, It includes the following steps: S1. Construct a polycrystalline 3C-SiC atomic model; S2. Simulate the crack propagation behavior of the polycrystalline 3C-SiC atomic model; S3. After obtaining the crack propagation behavior, use OVITO software to analyze the microstructure evolution of polycrystalline 3C-SiC; S4. After completing the analysis, construct a fracture property evaluation model; S5. According to the fracture property evaluation model in S4, construct a mechanical property prediction database based on molecular dynamics to realize the visualization analysis and quantitative prediction of the crack propagation behavior of 3C-SiC.

2. A method for predicting 3C-SiC crack propagation and mechanical properties according to claim 1, characterized in that The process of constructing the polycrystalline 3C-SiC atomic model in S1 is as follows: S11. Obtain the crystallographic information file of cubic silicon carbide through the Next Generation Materials Program database; S12. Use Atomsk software to execute the format conversion command to convert the crystallographic information file of cubic silicon carbide into the LAMMPS data format; S13. After converting the crystallographic information file of cubic silicon carbide into the LAMMPS data format, create a grain distribution configuration file, define the simulation box and specify the random grain distribution seed number; S14. Execute the command through the --polycrystal mode of Atomsk to generate a polycrystalline structure model; S15. Use the read function of the ASE library to read the basic polycrystalline structure model, and create models with different crack lengths in the central region of the (001) crystal plane within the range of [10, 20, 30, 40, 50] angstroms through the custom function add_crack; S16. Use the write function of ASE to output the LAMMPS format models with different crack lengths; S17. Generate a polycrystalline 3C-SiC atomic model with a complete crack series in the range of 0 angstroms to 50 angstroms through parametric control.

3. A method for predicting the crack propagation and mechanical properties of 3C-SiC according to claim 2, wherein, The process of simulating the crack propagation behavior of the polycrystalline 3C-SiC atomic model in S2 is as follows: S21. Adopt the Langevin heat bath algorithm to establish a temperature control system and build a thermodynamic environment module; S22. Set the temperature of the thermodynamic environment module between 300K and 1500K, and at the same time set the time step to 1fs. Tensile load the polycrystalline 3C-SiC atomic model obtained in S1, and then output the trajectory file; S23. Configure a dynamic loading control module to achieve mechanical loading through the coupling of a strain rate control model and the Verlet integration algorithm. Set the strain rate range to 10 9 to 10 11 s -1 , with the loading direction being [100]. After performing tensile loading again, output the trajectory file to obtain the crack propagation behavior under different temperature, strain rate, and crack size conditions.

4. A method for predicting the crack propagation and mechanical properties of 3C-SiC according to claim 3, characterized in that, The process of analyzing the microstructure evolution of polycrystalline 3C-SiC in S3 is as follows: S31. Integrate the defect evolution analysis module, and use the IDS topology command of the OVITO visualization platform to identify grain boundary atoms and use the DXA algorithm to analyze the trajectory file to realize dynamic defect tracking; S32. After completing the dynamic defect tracking, rely on the quantitative analysis method of the radial distribution function to analyze the grain boundary disordering kinetic process through the characteristic peak position shift and intensity attenuation; S33. Then use the stress cloud map three-dimensional reconstruction technology to observe the dynamic distribution characteristics of the stress field and realize the atomic-scale dynamic capture of the crack propagation path in combination with the stress cloud map.

5. A method for predicting the crack propagation and mechanical properties of 3C-SiC according to claim 4, characterized in that: The stress cloud map mentioned in S33 calculates the stress distribution at the crack tip, identifies the crack propagation mode, and analyzes the microscopic mechanism of the crack-grain boundary interaction in combination with the dislocation density statistics.

6. A method for predicting the crack propagation and mechanical properties of 3C-SiC according to claim 5, characterized in that: The fracture property evaluation model mentioned in S4 includes an energy dissipation analysis model, a microstructure correlation model, and a preferred path expansion prediction algorithm.

7. A method for predicting crack propagation and mechanical properties of 3C-SiC according to claim 6, characterized in that, The process of constructing the fracture property evaluation model in S4 is as follows: S41. Establish an energy dissipation analysis model based on the differences in energy release modes during crack propagation; S42. Establish a microstructure correlation model based on the quantitative relationship between grain size, crack length, and fracture toughness; S43. Establish a preferred path expansion prediction algorithm based on the analysis of crack propagation using a structure evolution diagram.

8. A method for predicting the crack propagation and mechanical properties of 3C-SiC according to claim 7, characterized in that: The differences in energy release modes in S41 are calculated using the Griffith criterion for predicting the effects of different crack sizes and grain structures on the toughness of 3C-SiC materials in combination with a modified fracture mechanics model.

9. A method for predicting the crack propagation and mechanical properties of 3C-SiC according to claim 8, characterized in that: The mechanical property prediction database in S5 is constructed based on multi-field coupled molecular dynamics simulation data.

Images