Analog method for dislocation-mediated ductile-to-brittle transition in diamond under hydrostatic pressure
By constructing a potential function model under hydrostatic pressure and optimizing the coefficients, combined with genetic algorithm screening, the problem of the difficulty in describing diamond dislocation slip in the existing technology was solved, and the accurate simulation of the ductile-brittle transition process of diamond was realized, improving the computational accuracy and performance of molecular dynamics simulation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI UNIV
- Filing Date
- 2023-12-20
- Publication Date
- 2026-05-19
AI Technical Summary
Existing molecular dynamics simulation methods are difficult to effectively describe the spatial motion of dislocations in diamond, especially during the ductile-brittle transition, which limits the study of the high strength and high hardness characteristics of diamond.
A potential function model based on hydrostatic pressure is adopted, and the undetermined coefficients of the potential function are optimized by combining a genetic algorithm. The potential function is constructed by the spherical coordination number method to simulate the sliding and ductile-brittle transition process of dislocations in diamond. This includes randomly generating the undetermined coefficients of the potential function, optimizing the solution, selecting potential functions that meet the material parameters, and simulating shear loading under high hydrostatic pressure.
Accurate simulation of the ductile-brittle transition process of diamond was achieved, improving the molecular dynamics simulation performance for the room-temperature plasticity of diamond, and enabling the description of {001} <110> and {111} <110> The dislocation slip mechanism has high calculation accuracy and is applicable to single-crystal or polycrystalline configurations.
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Figure CN117935962B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of molecular dynamics, and in particular to a simulation method based on dislocation-mediated ductile-brittle transition in diamond under hydrostatic pressure. Background Technology
[0002] Molecular dynamics simulations can simulate the deformation process of materials at the atomic scale, using simple potential functions to represent the interactions between atoms, and thus observe the evolution of various microstructures of atoms in real time during the deformation process of materials.
[0003] Due to the high strength and hardness of diamond, directly observing dislocation slip and the brittle-ductile transition using traditional experimental methods is significantly more difficult. Researchers have effectively suppressed microcrack propagation in diamond using hydrostatic pressure. The theory and atomic model of the brittle-ductile transition rely on an accurate description of dislocation behavior under hydrostatic pressure and brittle phenomena under zero pressure.
[0004] Most existing molecular dynamics (MD) simulations of dislocation behavior in diamond focus on {111} <110> In slip systems, however, in diamond, dislocation movement is highly stereooriented, involving the breaking and formation of covalent bonds as edge dislocations slide. This spatial motion limits the simulation of the ductile-brittle transition in diamond. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of the prior art in describing the spatial motion of diamond atoms, and to provide a simulation method based on dislocation-mediated ductile-brittle transition of diamond under hydrostatic pressure.
[0006] The objective of this invention can be achieved through the following technical solutions:
[0007] A simulation method for dislocation-mediated ductile-brittle transition in diamond under hydrostatic pressure includes the following steps:
[0008] S1: Construct a potential function model for dislocation-mediated diamond under hydrostatic pressure;
[0009] S2: Randomly generate undetermined coefficients of the potential function to obtain the material parameters of the diamond to be tested. Using the material parameters of the diamond to be tested as the target, optimize the undetermined coefficients of the potential function through a genetic algorithm to obtain multiple potential functions to be tested.
[0010] S3: From multiple potential functions to be measured, based on the parameter variation results of various diamond configurations under hydrostatic strain conditions with shear loading force, select potential functions that meet the material parameters of the diamond to be measured;
[0011] S4: Calculate the interaction potential parameters between diamond atoms based on the potential function that matches the material parameters of the diamond to be tested, and simulate the ductile-brittle transition of diamond mediated by dislocation under hydrostatic pressure through the interaction potential parameters.
[0012] Furthermore, the potential function model includes a potential function based on the spherical coordination number method.
[0013] Furthermore, the potential function based on the spherical coordination number method includes:
[0014] The total energy E of the system is calculated using the following expression:
[0015]
[0016] In the formula, f R and f A These are the repulsive and attractive terms, respectively, f C It is a smooth function, r ij It is the distance between atoms i and j, and the bond order term b. ij It is a multi-body term; the exclusion term f R and attraction item f A The expressions are as follows:
[0017]
[0018]
[0019] In the formula, A (n) B (n) , λ R (n) and λ B (n) All are coefficients to be fitted; a smoothing function f is used. C Restricting interatomic interactions:
[0020]
[0021] In the formula, r is the actual interatomic distance, R is the basic cutoff radius, and D is the error range; the bond order term b ij The chemical effect used to describe the strength of covalent bonds is calculated as follows:
[0022]
[0023] In the formula, ζ ij Let m be a bond angle function.
[0024]
[0025]
[0026]
[0027]
[0028] In the formula, δ is the coordination number of the spherical surface. kC δ jC All are Kronecker sign coefficients, θ ijk ,c,d,cosθ0,N0,γ,λ N (n) All of these are optimized parameters.
[0029] Furthermore, the specific process of optimizing and solving the undetermined coefficients of the potential function using a genetic algorithm is as follows:
[0030] S21: Randomly generate a batch of undetermined potential function coefficients as the first generation initial population for genetic algorithm optimization, and generate the first generation population potential function parent, and generate the offspring population potential function individuals based on the first generation population potential function parent, each population potential function individual includes potential function coefficients of all types.
[0031] S22: Read the material parameters of the diamond to be tested as the optimization target quantity, set the optimization weight for each physical quantity in the material parameters, read in the configuration information of the diamond, and generate a constraint matrix based on the configuration information;
[0032] S23: Based on the constraint matrix, calculate the fitted value corresponding to each individual in the current population, compare the fitted value with the target quantity, and calculate the residual value between each individual in the population and the target quantity based on the optimization weight of each physical quantity, thereby obtaining the fitness of each potential function individual;
[0033] S24: Randomly input two potential function parents, distinguish between dominant and inferior potential function parents based on the individual fitness of the potential function, perform inheritance on the dominant potential function parents, and delete the inferior potential function parents;
[0034] S25: Gene crossover and mutation are performed based on the set mutation probability and important mutation probability to generate offspring potential function individuals of the dominant potential function parent until the set population number is reached.
[0035] S26: Repeat S22-S25 until the residual between the fitted value and the target value is less than the preset threshold. Output the potential function of the individual whose fitness is higher than the preset value at this time as the potential function to be tested.
[0036] Furthermore, the calculation expression for the optimization process of the potential function is as follows:
[0037]
[0038] In the formula, Z represents the optimized residual; W kThe weight of the optimization quantity k is represented by k; K represents the total number of optimization quantities. and and represent the fitted value and target quantity of the material parameter k of the diamond to be tested, respectively.
[0039] Further, step S3 includes:
[0040] S31: Read in the potential function to be measured, input the corresponding material parameters of the diamond to be measured, and select the potential function whose error of each parameter meets the screening error range according to the set screening error range for each material parameter.
[0041] S32: For each potential function that meets the screening error range, use the specified first diamond configuration and apply progressively increasing shear loading under hydrostatic strain to screen out potential functions that can describe diamond dislocation slip.
[0042] S33: For potential functions that can describe the sliding of diamond dislocations, use the specified second diamond configuration, apply progressively increasing shear loading under hydrostatic strain, calculate the sliding of edge dislocations, and filter out potential functions that can describe the sliding ability of edge dislocations.
[0043] S34: For potential functions that can describe sliding ability, use the specified third diamond configuration, apply progressively increasing shear loading under hydrostatic strain, perform elastic constant tests, and screen out potential functions that can describe elastic modulus.
[0044] S35: For a potential function that can describe the elastic modulus, using the specified fourth diamond configuration, the dislocation emission capability under the condition of applied hydrostatic strain is obtained by gradually increasing shear loading.
[0045] Furthermore, the first diamond configuration is a 15nm×15nm×1nm diamond configuration with {111} crystal plane dislocations; the second diamond configuration is a 15nm×15nm×1nm diamond configuration with pre-placed {100} crystal plane edge dislocations; the third diamond configuration is a 1nm×1nm×1nm diamond configuration; and the fourth diamond configuration is a 69nm×60nm×1nm four-grain configuration with angles of 45, 0, 90, and 25 degrees, respectively.
[0046] Furthermore, the static strain is 0.15.
[0047] Furthermore, the maximum shear force under shear loading is 300 GPa.
[0048] Furthermore, the material parameters of the diamond to be tested include lattice constant, binding energy, hole energy, surface energy, and elastic modulus.
[0049] Compared with the prior art, the present invention has the following beneficial effects:
[0050] 1. This invention relates to a potential function for molecular dynamics simulation, applied to the molecular dynamics simulation of the ductile-brittle transition process in diamond under high hydrostatic pressure. The basic form of this potential function is the Tersoff-HP function, and parameters are optimized using a genetic algorithm. This potential function can effectively simulate the ductile-brittle transition process in single-crystal or polycrystalline configurations, and is useful for studying the {001} process in diamond. <110> and {111} <110> The dislocation slip mechanism has high computational accuracy.
[0051] 2. The method of this invention is a potential function developed for diamond, which improves the performance of MD simulation for the room temperature plasticity of diamond. Attached Figure Description
[0052] Figure 1 This is a flowchart of the present invention.
[0053] Figure 2 shows atomic-scale images of the potential function simulation of the diamond (100) plane dislocation slip mechanism according to the present invention. Different atoms are labeled with numbers and colored according to their Y-axis coordinates. The top and bottom rows of images are images of the crystal configurations along the
[110] and
[001] directions, respectively. The images are specifically divided into the following parts:
[0054] Figure 2a This is the first-stage configuration diagram of the glide dislocation slip on the diamond (100) plane, at which point shear strain has just been applied.
[0055] Figure 2b The diagram shows the second-stage configuration of the glide dislocation sliding on the diamond (100) plane. It can be seen that some bond corners begin to break and the dislocations begin to move.
[0056] Figure 2c This is the third-stage configuration diagram of the glide dislocation slip on the diamond (100) plane, representing the transition stage between the disappearance of the previous dislocation loop and the generation of the next dislocation loop.
[0057] Figure 2d This is the fourth stage configuration diagram of the glide dislocation sliding on the diamond (100) face. The dislocation slides forward to complete the sliding and forms a stable 5-7 ring.
[0058] Figure 2e This represents the change in the distance between atoms over time.
[0059] Figure 2f This represents the change in bond angles between atoms over time.
[0060] Figure 3a The TersoffHP potential function of this invention simulates the configuration of a diamond (100) surface glide dislocation after full relaxation.
[0061] Figure 3b The TersoffHP potential function of this invention simulates the configuration of a diamond (111) surface glide dislocation after full relaxation.
[0062] Figure 3c The TersoffHP potential function of this invention simulates the configuration of diamond (111) surface shuffle dislocations after full relaxation.
[0063] Figure 3d The atomic energy cloud diagrams near the dislocation core are shown for three types of dislocations under high hydrostatic strain of 0.0 (left) and 0.15 (right).
[0064] Figure 3e The volumetric stress contour plots near the dislocation core are shown for three types of dislocations under high hydrostatic strains of 0.0 (left) and 0.15 (right).
[0065] Figure 3f The Mises stress contour plots near the dislocation cores are shown for three types of dislocations under high hydrostatic strains of 0.0 (left) and 0.15 (right).
[0066] Figure 4a This is a schematic diagram of the loading conditions for simulating the diamond nanocrystalline polycrystalline model using the TersoffHP potential function of the present invention.
[0067] Figure 4b The TersoffHP potential function of this invention simulates the configuration of diamond nanocrystalline polycrystalline material after applying a compressive strain of 0.0.
[0068] Figure 4c The TersoffHP potential function of this invention simulates the configuration of diamond nanocrystalline polycrystalline material after applying a compressive strain of 0.15. Detailed Implementation
[0069] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.
[0070] Example 1
[0071] like Figure 1 As shown, this invention provides a simulation method for dislocation-mediated ductile-brittle transition in diamond under hydrostatic pressure, comprising the following steps:
[0072] S1: Construct a potential function model for dislocation-mediated diamond under hydrostatic pressure;
[0073] Furthermore, the potential function model includes a potential function based on the spherical coordination number method.
[0074] Furthermore, the potential function based on the spherical coordination number method includes:
[0075] The total energy E of the system is calculated using the following expression:
[0076]
[0077] In the formula, f R and f A These are the repulsive and attractive terms, respectively, f C It is a smooth function, r ij It is the distance between atoms i and j, and the bond order term b. ij It is a multi-body term; the exclusion term f R and attraction item f A The expressions are as follows:
[0078]
[0079]
[0080] In the formula, A (n) B (n) , λ R (n) and λ B (n) All are coefficients to be fitted; a smoothing function f is used. C Restricting interatomic interactions:
[0081]
[0082] In the formula, r is the actual interatomic distance, R is the basic cutoff radius, and D is the error range; the bond order term b ij The chemical effect used to describe the strength of covalent bonds is calculated as follows:
[0083]
[0084] In the formula, ζ ij Let m be a bond angle function.
[0085]
[0086]
[0087]
[0088]
[0089] In the formula, N ij C N represents the spherical coordination number, which is the number of carbon atoms bonded to atom i minus the bonding information between atom i and atom j.ij C The value increases significantly with increasing hydrostatic pressure, reflecting the properties of diamond under different pressures. kC δ jC All are Kronecker sign coefficients, θ ifk ,c,d,cosθ0,N0,γ,λ N (n) All are optimization parameters, λ N (n) Let be the coefficients to be fitted. The cutoff radius R of the potential function is... Similar to the Tersoff and Airebo potentials. Furthermore, the potential function model proposed in this embodiment does not consider the effects of long-range van der Waals forces.
[0090] S2: Randomly generate undetermined coefficients of the potential function to obtain the material parameters of the diamond to be tested. Using the material parameters of the diamond to be tested as the target, optimize the undetermined coefficients of the potential function through a genetic algorithm to obtain multiple potential functions to be tested.
[0091] S21: Randomly generate a batch of undetermined potential function coefficients as the first generation initial population for genetic algorithm optimization, and generate the first generation population potential function parent, and generate the offspring population potential function individuals based on the first generation population potential function parent, each population potential function individual includes potential function coefficients of all types.
[0092] S22: Read the material parameters of the diamond to be tested as the optimization target quantity, set the optimization weight for each physical quantity in the material parameters, read in the configuration information of the diamond, and generate a constraint matrix based on the configuration information;
[0093] S23: Based on the constraint matrix, calculate the fitted value corresponding to each individual in the current population, compare the fitted value with the target quantity, and calculate the residual value between each individual in the population and the target quantity based on the optimization weight of each physical quantity, thereby obtaining the fitness of each potential function individual;
[0094] S24: Randomly input two potential function parents, distinguish between dominant and inferior potential function parents based on the individual fitness of the potential function, perform inheritance on the dominant potential function parents, and delete the inferior potential function parents;
[0095] S25: Gene crossover and mutation are performed based on the set mutation probability and important mutation probability to generate offspring potential function individuals of the dominant potential function parent until the set population number is reached.
[0096] S26: Repeat S22-S25 until the residual between the fitted value and the target value is less than the preset threshold. Output the potential function of the individual whose fitness is higher than the preset value at this time as the potential function to be tested.
[0097] The calculation expression for the optimization process of the potential function is as follows:
[0098]
[0099] In the formula, Z represents the optimized residual; W k The weight of the optimization quantity k is represented by k; K represents the total number of optimization quantities. and and represent the fitted value and target quantity of the material parameter k of the diamond to be tested, respectively.
[0100] S3: From multiple potential functions to be measured, based on the parameter variations of various diamond configurations under hydrostatic strain conditions with shear loading force, select potential functions that match the material parameters of the diamond to be measured; specifically including:
[0101] S31: Read in the potential function to be measured, input the corresponding material parameters of the diamond to be measured, and select the potential function whose error of each parameter meets the screening error range according to the set screening error range for each material parameter.
[0102] S32: For each potential function that meets the screening error range, a diamond configuration of 15nm×15nm×1nm with {111} plane dislocations is used. Under the condition of applying hydrostatic strain ε=0.15, a gradually increasing shear load is applied, with a maximum shear force of 300GPa, to screen out potential functions that can describe diamond dislocation slip.
[0103] S33: For the potential function that can describe the sliding of diamond dislocations, a diamond configuration of 15nm×15nm×1nm is used. Under the condition of applying hydrostatic strain ε=0.15, the shear loading is gradually increased and the maximum shear force is 300GPa. The sliding of edge dislocations is calculated and the potential function that can describe the sliding ability of edge dislocations is selected.
[0104] S34: For the potential function that can describe the sliding ability, a diamond configuration of 1nm×1nm×1nm is used. Under the condition of applying hydrostatic strain ε=0.15, the shear loading is gradually increased and the maximum shear force is 300GPa. The elastic constant is tested to screen out the potential function that can describe the elastic modulus.
[0105] S35: For a potential function that can describe the elastic modulus, a four-grain diamond configuration of 69nm×60nm×1nm is used, with successively applied compressive strain of ε=0.15 at degrees of 45, 0, 90, and 25, to obtain the dislocation emission capability under this configuration.
[0106] S4: Calculate the interaction potential parameters between diamond atoms based on the potential function that matches the material parameters of the diamond to be tested, and simulate the ductile-brittle transition of diamond mediated by dislocation under hydrostatic pressure through the interaction potential parameters.
[0107] Table 1 presents the parametric solutions of the potential function proposed in this embodiment. Then, these parametric solutions are substituted into the basic equation of the potential function, and the material parameters in Table 2 are calculated using the basic formula of the potential function.
[0108] Table 1 Parametric solutions of the potential function
[0109]
[0110] Table 2 shows the material parameters used for potential function fitting, along with their optimized and target parameters.
[0111]
[0112] As shown in Table 2, the difference between the optimized and target values for fitting the main material parameters of diamond using the potential function model in this embodiment is very small.
[0113] The results show that the estimates of the lattice constant and cohesive energy of the diamond lattice are relatively accurate compared to the target values. Although there are some differences between the fitted values of other potential functions and the experimental values, the overall stability of the lattice structure is consistent with the predicted material properties.
[0114] Based on the obtained potential function, a diamond configuration with glide dislocations was subjected to shear loading under hydrostatic pressure, and the simulation results are shown in Figure 2. As can be seen from the figure, with loading, the ductile dislocations initially undergo a gradual shearing process. After an elastic accumulation process, the carbon-carbon bonds enter a rapid transition state, reconstructing a stable 5-7 ring, indicating significant geometric deformation and demonstrating its unique sliding mechanism.
[0115] Figure 3 shows the configuration simulation results of edge dislocations on the (100) plane, (111)-glide plane, and (111)-shuffle plane. The figure shows the distribution of atomic energy, volume stress, and Mises stress near the dislocation core under hydrostatic strains of 0.0 and 0.15.
[0116] The simulation results of applying hydrostatic strains of 0.0 and 0.15 to diamond nanocrystalline materials are shown in Figure 4. For the 0.0 hydrostatic strain sample, cracks are generated at the grain boundaries and propagate directly into the diamond grains in front. Conversely, when the hydrostatic strain is increased to 0.15, a series of dislocations are generated at the (010) grain boundaries. This indicates that the Tersoff HP potential of this invention can describe the dislocation-mediated room-temperature plasticity and hydrostatic strain-induced ductile-brittle transition mechanism in diamond.
[0117] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.
Claims
1. A simulation method for dislocation-mediated ductile-brittle transition in diamond under hydrostatic pressure, characterized in that, Includes the following steps: S1: Construct a potential function model for dislocation-mediated diamond under hydrostatic pressure; the potential function model includes a potential function based on the spherical coordination number method; the potential function based on the spherical coordination number method includes: Total energy of the system E The calculation expression is: In the formula, and These are the repulsive and attractive terms, respectively. It is a smooth function. It is an atom i and j Distance between, key-level terms It is a multi-body term; a exclusion term. and attraction The expressions are as follows: In the formula, , , and All coefficients are to be fitted; a smoothing function is used. Restricting interatomic interactions: In the formula, r is the actual interatomic distance, R is the basic cutoff radius, and D is the error range; bond order term The chemical effect used to describe the strength of covalent bonds is calculated as follows: In the formula, Key angle function: In the formula, The coordination number of the spherical surface. , All are Kronecker sign coefficients. c, d 、 、 、 All are optimized parameters; S2: Randomly generate undetermined coefficients of the potential function to obtain the material parameters of the diamond to be tested. Using the material parameters of the diamond to be tested as the target, optimize the undetermined coefficients of the potential function through a genetic algorithm to obtain multiple potential functions to be tested. S3: From multiple potential functions to be measured, based on the parameter variation results of various diamond configurations under hydrostatic strain conditions with shear loading force, select potential functions that meet the material parameters of the diamond to be measured; S4: Calculate the interaction potential parameters between diamond atoms based on the potential function that matches the material parameters of the diamond to be tested, and simulate the ductile-brittle transition of diamond mediated by dislocation under hydrostatic pressure through the interaction potential parameters.
2. The simulation method for dislocation-mediated ductile-brittle transition in diamond under hydrostatic pressure according to claim 1, characterized in that, The specific process of optimizing and solving the undetermined coefficients of the potential function using a genetic algorithm is as follows: S21: Randomly generate a batch of undetermined potential function coefficients as the first generation initial population for genetic algorithm optimization, and generate the first generation population potential function parent, and generate the offspring population potential function individuals based on the first generation population potential function parent, each population potential function individual includes potential function coefficients of all types. S22: Read the material parameters of the diamond to be tested as the optimization target quantity, set the optimization weight for each physical quantity in the material parameters, read in the configuration information of the diamond, and generate a constraint matrix based on the configuration information; S23: Based on the constraint matrix, calculate the fitted value corresponding to each individual in the current population, compare the fitted value with the target quantity, and calculate the residual value between each individual in the population and the target quantity based on the optimization weight of each physical quantity, thereby obtaining the fitness of each potential function individual; S24: Randomly input two potential function parents, distinguish between dominant and inferior potential function parents based on the individual fitness of the potential function, perform inheritance on the dominant potential function parents, and delete the inferior potential function parents; S25: Gene crossover and mutation are performed based on the set mutation probability and important mutation probability to generate offspring potential function individuals of the dominant potential function parent until the set population number is reached. S26: Repeat S22-S25 until the residual between the fitted value and the target value is less than the preset threshold. Output the potential function of the individual whose fitness is higher than the preset value at this time as the potential function to be tested.
3. The simulation method for dislocation-mediated ductile-brittle transition in diamond under hydrostatic pressure according to claim 2, characterized in that, The calculation expression for the optimization process of the potential function is as follows: In the formula, Z Residuals representing optimization; W k Indicates optimization quantity k The weights; K Indicates the total number of optimizations; and These represent the material parameters of the diamond being tested. k The fitted value and the target quantity.
4. The simulation method for dislocation-mediated ductile-brittle transition in diamond under hydrostatic pressure according to claim 1, characterized in that, Step S3 includes: S31: Read in the potential function to be measured, input the corresponding material parameters of the diamond to be measured, and select the potential function whose error of each parameter meets the screening error range according to the set screening error range for each material parameter. S32: For each potential function that meets the screening error range, use the specified first diamond configuration and apply progressively increasing shear loading under hydrostatic strain to screen out potential functions that can describe diamond dislocation slip. S33: For potential functions that can describe the sliding of diamond dislocations, use the specified second diamond configuration, apply progressively increasing shear loading under hydrostatic strain, calculate the sliding of edge dislocations, and filter out potential functions that can describe the sliding ability of edge dislocations. S34: For potential functions that can describe sliding ability, use the specified third diamond configuration, apply progressively increasing shear loading under hydrostatic strain, perform elastic constant tests, and screen out potential functions that can describe elastic modulus. S35: For a potential function that can describe the elastic modulus, using the specified fourth diamond configuration, the dislocation emission capability under the condition of applied hydrostatic strain is obtained by gradually increasing shear loading.
5. The simulation method for dislocation-mediated ductile-brittle transition in diamond under hydrostatic pressure according to claim 4, characterized in that, The first diamond configuration is a 15nm×15nm×1nm diamond configuration with {111} crystal facet dislocations; the second diamond configuration is a 15nm×15nm×1nm diamond configuration with pre-placed {100} crystal facet edge dislocations; the third diamond configuration is a 1nm×1nm×1nm diamond configuration; and the fourth diamond configuration is a 69nm×60nm×1nm four-grain configuration with angles of 45, 0, 90, and 25 degrees, respectively.
6. The simulation method for dislocation-mediated ductile-brittle transition in diamond under hydrostatic pressure according to claim 1, characterized in that, The hydrostatic strain is 0.
15.
7. The simulation method for dislocation-mediated ductile-brittle transition in diamond under hydrostatic pressure according to claim 1, characterized in that, The maximum shear force of the shear loading is 300 GPa.
8. The simulation method for dislocation-mediated ductile-brittle transition in diamond under hydrostatic pressure according to claim 1, characterized in that, The material parameters of the diamond to be tested include lattice constant, binding energy, hole energy, surface energy, and elastic modulus.