CN116090253B - Molecular dynamics simulation method and device for electron impact dislocation effect - Google Patents
Molecular dynamics simulation method and device for electron impact dislocation effect Download PDFInfo
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Abstract
The invention relates to the technical field of material processing, in particular to a molecular dynamics simulation method and device for electron impact dislocation. Aiming at the technical problem that the quantitative simulation of the effect of electron impact dislocation cannot be realized, the scheme comprises the following steps: determining the incident energy of electrons; randomly selecting at least one scattering angle; determining, for each scattering angle, a velocity vector obtained by an impacted atom when the electron is scattered at a selected scattering angle after striking the dislocation when the electron is incident to a region where the dislocation of the crystal model is located; inputting the determined at least one velocity vector into molecular dynamics simulation software to obtain simulation data for simulating all atomic states in a crystal model after the molecular dynamics simulation software endows at least one velocity vector to at least one target atom in a one-to-one correspondence manner; and simulating the slip process of dislocation in the crystal model according to the simulation data. According to the scheme, the slip process of dislocation after electron impact dislocation can be quantitatively simulated.
Description
Technical Field
The embodiment of the invention relates to the technical field of material processing, in particular to a molecular dynamics simulation method and device for electron impact dislocation.
Background
With the rapid development of high-end industries such as aerospace and the like, the complexity of the shape of the component is continuously improved, and particularly, the plastic deformation capability of lightweight materials such as titanium alloy and the like is poor, so that the difficulty of forming the component is greatly increased. The electro-plastic forming refers to applying current to a formed piece in the forming process, and the theoretical basis is the electro-plastic effect of metal, and the interaction between drift electrons and dislocation is utilized to promote dislocation slip, so that the plastic deformation capability of the formed piece is improved. Therefore, the force of electrons on dislocations (i.e., electron wind force) is the most important theoretical system for the electro-plastic forming technique.
At present, the mechanism of the electron impact dislocation action is still limited to the theoretical analysis based on experience, and is in a qualitative analysis stage, so that the quantitative simulation of the electron impact dislocation action cannot be realized.
Disclosure of Invention
The embodiment of the invention provides a molecular dynamics simulation method and a device for electron impact dislocation, which can quantitatively simulate the slip process of dislocation after electron impact dislocation.
In a first aspect, an embodiment of the present invention provides a molecular dynamics simulation method for electron impact dislocation, including:
s1, establishing a crystal model to be simulated by using molecular dynamics simulation software; the surface of the crystal model includes at least one dislocation;
s2, determining the incident energy of electrons;
s3, randomly selecting at least one scattering angle in a preset scattering angle range;
s4, determining a speed vector acquired by the impacted atoms when the electrons impact the dislocation and scatter at the selected scattering angle according to the incidence energy when the electrons impact the dislocation in the dislocation area of the crystal model according to the incidence energy;
s5, inputting the determined at least one speed vector into the molecular dynamics simulation software to obtain simulation data for simulating all atomic states in the crystal model after the molecular dynamics simulation software endows at least one speed vector to at least one target atom in a one-to-one correspondence manner; the target atoms are positioned in the dislocation area;
s6, simulating the slip process of dislocation in the crystal model according to the simulation data.
In a second aspect, an embodiment of the present invention further provides a molecular dynamics simulation apparatus for electron impact dislocation, including:
the crystal model building unit is used for building a crystal model to be simulated by utilizing molecular dynamics simulation software; the surface of the crystal model includes at least one dislocation;
a first determining unit for determining an incident energy of electrons;
a selection unit for randomly selecting at least one scattering angle within a preset scattering angle range;
a second determining unit configured to determine, for each randomly selected scattering angle, a velocity vector acquired by an impacted atom when the electron is scattered at the selected scattering angle after striking the dislocation when the electron is incident to a region where the dislocation of the crystal model is located, according to the incident energy;
the simulation data acquisition unit is used for inputting the determined at least one speed vector into the molecular dynamics simulation software to acquire simulation data for simulating all atomic states in the crystal model after the molecular dynamics simulation software endows at least one speed vector to at least one target atom in a one-to-one correspondence manner; the target atoms are positioned in the dislocation area;
and the simulation unit is used for simulating the slip process of dislocation in the crystal model according to the simulation data.
In a third aspect, an embodiment of the present invention further provides an electronic device, including a memory and a processor, where the memory stores a computer program, and when the processor executes the computer program, the method described in any embodiment of the present specification is implemented.
In a fourth aspect, embodiments of the present invention also provide a computer-readable storage medium having stored thereon a computer program which, when executed in a computer, causes the computer to perform a method according to any of the embodiments of the present specification.
The embodiment of the invention provides a molecular dynamics simulation method and a device for electron impact dislocation action, which are characterized in that through analyzing the process of electron impact dislocation action, after an electron beam enters a dislocation area, not every incident electron impacts atoms in the dislocation area, and the scattering angle of the electron after impacting the atoms is random, so that at least one scattering angle is randomly selected and the velocity vector of the impacted atoms after impacting the atoms and scattering the electrons at the scattering angle is determined on the assumption that at least one electron collides with the atoms in every incident electron; in addition, because the molecular dynamics simulation software can quantitatively simulate the process related to the atomic motion path, the determined at least one velocity vector is input into the molecular dynamics simulation software, so that the molecular dynamics simulation software can quantitatively simulate the slip process of the dislocation in the crystal model by utilizing the simulation data after giving at least one velocity vector to at least one target atom in the dislocation area in a one-to-one correspondence manner. Therefore, the sliding process of dislocation after electron impact dislocation can be quantitatively simulated by the scheme.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a molecular dynamics simulation method of electron impact dislocation action according to an embodiment of the present invention;
FIG. 2 is a flow chart of another molecular dynamics simulation method of electron impact dislocation action according to an embodiment of the present invention;
FIG. 3 is a hardware architecture diagram of an electronic device according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a molecular dynamics simulation apparatus for electron impact dislocation according to an embodiment of the present invention;
FIG. 5 is a block diagram of another molecular dynamics simulation apparatus for electron impact dislocation action according to an embodiment of the present invention;
FIG. 6 is a block diagram of a molecular dynamics simulation apparatus for electron impact dislocation action according to an embodiment of the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of 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, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments, and all other embodiments obtained by those skilled in the art without making any inventive effort based on the embodiments of the present invention are within the scope of protection of the present invention.
As previously mentioned, the mechanism for electron impact dislocation action is still limited to empirical based theoretical analysis, in the qualitative analysis stage, and quantitative simulation of electron impact dislocation action cannot be achieved.
For the blank of the quantitative simulation of the electron impact dislocation effect, the inventor performs analysis that the pulse current generates impact effect when electrons flow through metal, and the generated impact effect can enable lattice node atoms to move when the energy passing through the unit section of the crystal in unit time is larger. And the crystal has dislocation, which indicates that partial lattice nodes in the crystal are dislocated, and when electrons strike the dislocation area, atoms in the dislocation area move, so that the dislocation slip is characterized.
Further analysis, molecular dynamics simulation software can quantitatively simulate a basic process related to an atomic motion path, is a very effective atomic scale simulation technology, and can provide details of atomic characteristics on many microscopic scales. Based on this, it is considered to realize the simulation of dislocation slip after electron impact dislocation by using molecular dynamics simulation software. In order to simulate the electron impact dislocation effect by using molecular dynamics simulation software, the process of the electron impact dislocation effect can be determined outside the molecular dynamics simulation software, so that the determined velocity vector obtained by the impacted atoms is input into the molecular dynamics simulation software, and the molecular dynamics simulation software simulates all the atom states in the established crystal model, thereby realizing the whole simulation process of the electron impact dislocation effect.
Specific implementations of the above concepts are described below.
Referring to fig. 1, an embodiment of the present invention provides a molecular dynamics simulation method for electron impact dislocation, which includes:
s1, establishing a crystal model to be simulated by using molecular dynamics simulation software; the surface of the crystal model includes at least one dislocation;
s2, determining the incident energy of electrons;
s3, randomly selecting at least one scattering angle in a preset scattering angle range;
s4, determining a speed vector acquired by the impacted atoms when the electrons impact the dislocation and scatter at the selected scattering angle according to the incidence energy when the electrons impact the dislocation in the dislocation area of the crystal model according to the incidence energy;
s5, inputting the determined at least one speed vector into the molecular dynamics simulation software to obtain simulation data for simulating all atomic states in the crystal model after the molecular dynamics simulation software endows at least one speed vector to at least one target atom in a one-to-one correspondence manner; the target atoms are positioned in the dislocation area;
s6, simulating the slip process of dislocation in the crystal model according to the simulation data.
In the embodiment of the invention, through analyzing the process of electron impact dislocation, after the electron beam enters the dislocation area, not every incident electron impacts atoms in the dislocation area, and the scattering angle of the electron for scattering after impacting atoms is random, so that at least one scattering angle is randomly selected and the velocity vector of the impacted atoms after impacting atoms and scattering at the scattering angle is determined on the assumption that at least one electron collides with atoms in every incident electron; in addition, because the molecular dynamics simulation software can quantitatively simulate the process related to the atomic motion path, the determined at least one velocity vector is input into the molecular dynamics simulation software, so that the molecular dynamics simulation software can quantitatively simulate the slip process of the dislocation in the crystal model by utilizing the simulation data after giving at least one velocity vector to at least one target atom in the dislocation area in a one-to-one correspondence manner. Therefore, the sliding process of dislocation after electron impact dislocation can be quantitatively simulated by the scheme.
The manner in which the individual steps shown in fig. 1 are performed is described below.
Firstly, aiming at the step S1, a crystal model to be simulated is established by utilizing molecular dynamics simulation software; the surface of the crystal model includes at least one dislocation.
The molecular dynamics simulation method is a method for simulating physical motion tracks and states of atoms and molecules based on Newton mechanics principle. Currently, there are several types of molecular dynamics simulation software, such as Lammps, materials studio, ls1-MarDyn, IMD, coMD, and the like.
Before a crystal model is built by using molecular dynamics simulation software, the crystal structure of a crystal to be simulated needs to be known, wherein the surface of the crystal to be simulated comprises at least one dislocation. By inputting the relevant parameters of the crystal structure of the crystal to be simulated into the molecular dynamics simulation software, a corresponding crystal model can be established.
In this embodiment, molecular dynamics simulation software Lammps is taken as an example for illustration. When a crystal model is built, nvt ensemble can be adopted for relaxation, and an Anderson thermostat is adopted for controlling the system temperature after electron scattering; a fixed boundary condition is applied to the upper and lower surfaces of the crystal model using the Velocity-Verlet algorithm, with periodic boundary conditions applied to the remaining surfaces. Since the surface of the crystal to be simulated includes at least one dislocation, the surface of the established crystal model also contains at least one dislocation.
Then, for step S2", step S3", at least one scattering angle is randomly selected within a preset scattering angle range, and step S4", for each randomly selected scattering angle, the velocity vector" obtained by the impacted atoms when the electrons are scattered at the selected scattering angle after striking the dislocations when determining the electrons strike the dislocation region of the crystal model according to the incident energy when the electrons strike the dislocation region is described.
In the embodiment of the invention, since the displacement change of atoms in the crystal is different when electrons with different incident energy strike the crystal, in order to accurately simulate the slip condition of dislocation, the incident energy of the electrons incident to the dislocation area of the crystal model needs to be determined.
During the process of electron impact dislocation, a large amount of electrons are incident to the dislocation area, but not every incident electron impacts atoms in the dislocation area, so the number of the electron impact atoms is random; in addition, the scattering occurs after the electron collides with the atom, and the scattering angle is random; based on this, assuming that when an electron beam is incident on the region where the dislocation is located, the number of electrons colliding with atoms in the region where the dislocation is located is randomly determined, for example, the number of electrons is one, for example, the number of electrons is 10, and each electron colliding is scattered, the scattering angle of each electron colliding is randomly determined, that is, at least one scattering angle needs to be randomly selected in a preset scattering angle range, and the randomly selected scattering angle number is the same as the number of electrons colliding.
Wherein the predetermined scattering angle range is (0, 180 °).
In the embodiment of the invention, since the molecular dynamics simulation software can only simulate the process related to the movement path of the atoms, the velocity vector of the atoms needs to be determined outside the molecular dynamics simulation software. Specifically, after an electron impinges on an atom, the velocity vector acquired by the impinging atom can be determined by the following means (S41 to S44):
and S41, determining energy transferred to the impacted atoms when electrons impact the dislocation and scatter at a selected scattering angle after the electrons impact the dislocation when the electrons are incident on the dislocation area of the crystal model based on the principle of energy conservation and the incident energy.
Based on the principle of conservation of energy, the energy transferred to an impacted atom can be calculated using the following formula:
wherein E is t For energy transferred to the impacted atoms; m is atomic mass; e (E) e 、m e θ is the incident energy, mass, and scattering angle of the electrons, respectively; c is the speed of light.
S42, determining the speed of electrons after scattering and the speed obtained by the impacted atoms according to the energy of the impacted atoms.
Wherein the velocity v' after electron scattering can be calculated using the following formula:
wherein the velocity v obtained by the impacted atoms can be calculated using the formula s ：
S43, determining the scattering angle of the impacted atom according to the speed of the electrons after scattering, the speed obtained by the impacted atom and the scattering angle.
Wherein the scattering angle ψ of the impacted atom can be calculated using the following formula:
wherein, gamma is Lorentz factor.
S44, randomly generating an azimuth angle within a preset azimuth angle range, and calculating a velocity vector obtained by the impacted atom based on the randomly generated azimuth angle and the scattering angle of the impacted atom
Wherein, the liquid crystal display device comprises a liquid crystal display device,for azimuth angle, the preset azimuth angle range is [0,2 pi ]]。
In the embodiment of the present invention, for each randomly selected scattering angle, the speed vector obtained by each impacted atom after the electrons scatter to the corresponding scattering angle after impacting the atom can be determined by using S41 to S44, so as to obtain at least one speed vector.
Finally, inputting the determined at least one velocity vector into the molecular dynamics simulation software aiming at the step S5' to obtain simulation data for simulating all atom states in the crystal model after the molecular dynamics simulation software endows at least one velocity vector to at least one target atom in a one-to-one correspondence manner; the "target atoms are located in the region where the dislocations are located" and the step S6 "simulate the slip process of the dislocations in the crystal model according to the simulation data" are simultaneously described.
The molecular dynamics simulation software, after receiving the input at least one velocity vector, assigns the at least one velocity vector to at least one target atom in a one-to-one correspondence to simulate all atom states in the crystal model. Since electrons need to be incident to the dislocation region during the formation of the member, the target atoms (i.e., impacted atoms) are located in the dislocation region in order to quantify the slip of the dislocation. It can be seen that in the embodiment of the present invention, it is necessary to determine each target atom that is impacted during the process of impact dislocation of electrons.
In the embodiment of the invention, the target atoms can be determined by molecular dynamics simulation software, or can be determined outside the molecular dynamics simulation software and input into the molecular dynamics simulation software, but no matter which main body determines the target atoms, the target atoms can be determined by the following determination method: determining each atom positioned in the dislocation position area based on the crystal model established by the molecular dynamics simulation software; at least one target atom of the same number as the velocity vector is randomly selected among the individual atoms located in the region where the dislocation is located.
After the crystal model is built, the positions of all atoms in the crystal model can be known, and when electrons enter the dislocation area, the electrons impact with electrons on the surface of the crystal, so that target atoms can be selected from the atoms on the surface of the crystal based on the positions of all the atoms; in addition, if at least one dislocation is contained on the surface of the crystal model, the region where the dislocation is located may be defined in advance, and a target atom among atoms located on the crystal surface in the region where the dislocation is located may be selected.
To further improve the simulation accuracy, the same number of atoms as the velocity vector are randomly selected as target atoms within the atomic range satisfying the target atoms.
After determining the at least one target atom outside the molecular dynamics simulation software, further comprises: information of the at least one target atom is input into the molecular dynamics simulation software. Wherein the inputting may be performed simultaneously with inputting the determined at least one velocity vector into the molecular dynamics simulation software.
The molecular dynamics simulation software may be configured to assign at least one velocity vector to at least one target atom in a one-to-one correspondence manner.
After electrons are incident to the dislocation region of the crystal model, the impacted atoms undergo displacement change based on the imparted velocity vector, and when the displacement change occurs, the displacement change of other atoms in the crystal model can be caused, and when a large number of atoms in the crystal model undergo displacement change, the crystal structure changes.
The simulation data comprise atomic positions of all atoms in the crystal model before simulation and atomic positions after simulation. In the embodiment of the invention, the displacement change of each atom can be determined based on the atomic positions of all atoms in the crystal model before simulation and the atomic positions after simulation, and the dislocation slip process in the crystal model can be simulated based on the displacement change of each atom.
Further, since a structural stability of the inside of the crystal model can be achieved after a period of action is required after a beam of electrons is incident on the dislocation region of the crystal model, in one embodiment of the present invention, when the molecular dynamics simulation software outputs the simulation data within the period of action after the period of action is reached in step S5, so as to simulate the slip process of the dislocation after the beam of electrons is incident on the dislocation region of the crystal model.
In order to simulate the dislocation area where the electron beam continuously enters the crystal model, so that the crystal structure is gradually formed, the structure of the crystal model after dislocation slip can be determined as a new crystal model after each electron beam enters the dislocation area of the crystal model, and the new crystal model is used for executing S3, S4, S5 and S6 in a return mode so as to continuously simulate the slip process of the dislocation in the crystal model when the next electron impinges on the dislocation.
Because the molecular dynamics simulation software can only output the simulation data, the slip process of dislocation in the crystal model can be visually displayed by utilizing the visual software through analyzing the simulation data, so that the slip process of dislocation in the action process of electron impact dislocation can be intuitively represented.
It should be noted that, the steps other than the molecular dynamics simulation software may be implemented by Python language, C language, java language, and the like.
Based on the analysis in the above embodiment, after the electrons are incident on the dislocation region of the crystal model, the impacted atoms may undergo a displacement change based on the imparted velocity vector, but the displacement change may not cause the displacement change of other atoms in the crystal model, i.e. the crystal structure is not changed, so that the embodiment of the present invention provides another molecular dynamics simulation method for the impact dislocation effect of electrons, please refer to fig. 2, which may include:
s1, establishing a crystal model to be simulated by using molecular dynamics simulation software; the surface of the crystal model includes at least one dislocation.
S2, determining the incident energy of electrons.
S3, randomly selecting at least one scattering angle in a preset scattering angle range.
S4, determining a speed vector acquired by the impacted atoms when the electrons impact the dislocation and scatter at the selected scattering angle according to the incidence energy when the electrons impact the dislocation in the dislocation area of the crystal model according to the incidence energy.
S5, inputting the determined at least one speed vector into the molecular dynamics simulation software to obtain simulation data for simulating all atomic states in the crystal model after the molecular dynamics simulation software endows at least one speed vector to at least one target atom in a one-to-one correspondence manner; the target atoms are located in the region where the dislocations are located.
It should be noted that steps S1 to S5 in the present embodiment are the same as steps S1 to S5 in the above embodiment, and are not described in detail herein.
S50, judging whether the structure of the crystal model can be changed according to simulation data corresponding to the condition that the molecular dynamics simulation software simulates all the atomic states in the crystal model to reach a set first time threshold; if yes, executing step S51; if the determination result is no, step S52 is executed.
S51, simulating all atomic states in the crystal model according to the molecular dynamics simulation software, wherein the simulation data corresponds to the simulation data when the set second time threshold is reached, and S6 is executed; the second time threshold is greater than the first time threshold.
And S52, triggering the molecular dynamics simulation software to stop simulation, and returning to executing S3, S4, S5 and S50.
For example, if the crystal structure changes after the electron collides with the atom and the crystal structure can be stabilized after 10000 steps or 5 picoseconds of simulation time period (i.e. the second time threshold), in order to improve the simulation efficiency, a first time threshold may be set, for example, the first time threshold is 2000 steps or 1 picosecond, if the simulation data when the first time threshold is simulated by the molecular dynamics simulation software is determined, whether the speed vector input by S3 can change the structure of the crystal model may be determined, if the change is determined, the simulation of the molecular dynamics simulation software may be continued until the simulation time length reaches the set second time threshold, and if the structure of the crystal model is determined to be stabilized, the simulation of the dislocation sliding process in step S6 is performed; if it is determined that the crystal model cannot be changed, waiting is not needed, and a scattering angle capable of changing the structure of the crystal model needs to be selected again, so that waiting time can be shortened, and simulation efficiency is improved.
In the embodiment of the present invention, in step S50, it may be determined whether the structure of the crystal model may be changed at least by: calculating the displacement of each atom in the first time threshold according to the atom position of each atom in the crystal model before simulation and the atom position after simulation; judging whether the maximum displacement in all atoms is larger than a set displacement threshold value; if yes, determining that the structure of the crystal model can be changed; otherwise, it is determined that the structure of the crystal model does not change.
In addition to this determination, other determination methods may be used, such as directly determining whether the structure of the crystal model is changed based on the velocity vector or the energy transferred to the impacted atoms.
S6, simulating the slip process of dislocation in the crystal model according to the simulation data.
After step S6, the structure of the crystal model after dislocation slip may also be determined as a new crystal model, and S3, S4, S5, S50, S51, S52, and S6 are performed back using the new crystal model to continue the slip process of dislocations in the crystal model when the next electron hits the dislocation.
As shown in fig. 3 and 4, the embodiment of the invention provides a molecular dynamics simulation device for electron impact dislocation. The apparatus embodiments may be implemented by software, or may be implemented by hardware or a combination of hardware and software. In terms of hardware, as shown in fig. 3, a hardware architecture diagram of an electronic device where a molecular dynamics simulation apparatus with an electron impact dislocation function provided in an embodiment of the present invention is located, where the electronic device where the embodiment is located may include other hardware, such as a forwarding chip responsible for processing a message, in addition to a processor, a memory, a network interface, and a nonvolatile memory shown in fig. 3. For example, as shown in fig. 4, the device in a logic sense is formed by reading a corresponding computer program in a nonvolatile memory into a memory by a CPU of an electronic device where the device is located. The molecular dynamics simulation device for electron impact dislocation provided in this embodiment includes:
a crystal model building unit 401, configured to build a crystal model to be simulated by using molecular dynamics simulation software; the surface of the crystal model includes at least one dislocation;
a first determining unit 402 for determining an incident energy of electrons;
a selection unit 403 for randomly selecting at least one scattering angle within a preset scattering angle range;
a second determining unit 404, configured to determine, for each randomly selected scattering angle, a velocity vector acquired by an impacted atom when the electron is scattered at the selected scattering angle after striking the dislocation when the electron is incident on a region where the dislocation of the crystal model is located, according to the incident energy;
the simulation data obtaining unit 405 is configured to input the determined at least one velocity vector into the molecular dynamics simulation software, so as to obtain simulation data that the molecular dynamics simulation software assigns the at least one velocity vector to at least one target atom in a one-to-one correspondence, and then simulate all atom states in the crystal model; the target atoms are positioned in the dislocation area;
and a simulation unit 406 for simulating a slip process of dislocation in the crystal model according to the simulation data.
In one embodiment of the present invention, when determining, according to the incident energy, a velocity vector acquired by the impacted atoms when the electrons impact the dislocation and scatter at the selected scattering angle after the electrons impact the dislocation when the electrons are incident on the dislocation region of the crystal model, the second determining unit 404 specifically includes:
based on the principle of energy conservation and the incident energy, determining energy transferred to the impacted atoms when electrons impact the dislocation and scatter at a selected scattering angle when the electrons impact the dislocation when entering the dislocation area of the crystal model;
determining the speed of electrons after scattering and the speed obtained by the impacted atoms according to the energy of the impacted atoms;
determining a scattering angle of the impacted atom based on the velocity of the electrons after scattering, the velocity obtained by the impacted atom, and the scattering angle;
randomly generating an azimuth angle within a preset azimuth angle range, and calculating a speed vector acquired by the impacted atom based on the randomly generated azimuth angle and the scattering angle of the impacted atom.
In one embodiment of the present invention, the second determining unit 404 is further configured to determine, based on the crystal model established by the molecular dynamics simulation software, each atom located in the dislocation region; at least one target atom of the same number as the velocity vector is randomly selected among the individual atoms located in the region where the dislocation is located to trigger the simulation data acquisition unit 405 to input information of the at least one target atom into the molecular dynamics simulation software.
In one embodiment of the present invention, referring to fig. 5, the apparatus further includes: a structural change judging unit 407 for performing the following operations:
judging whether the structure of the crystal model can be changed according to simulation data corresponding to the condition that the molecular dynamics simulation software simulates all the atomic states in the crystal model to reach a set first time threshold;
if the judgment result is yes, executing the slip process of dislocation in the crystal model according to the simulation data corresponding to the condition that the simulation of all the atomic states in the crystal model is carried out by the molecular dynamics simulation software and reaches the set second time threshold; the second time threshold is greater than the first time threshold;
if the judgment result is no, triggering the molecular dynamics simulation software to stop simulation, and triggering the selection unit 403, the second determination unit 404, the simulation data acquisition unit 405 and the structural change judgment unit 407 to re-execute the corresponding operations.
In one embodiment of the invention, the simulation data comprises: atomic positions before simulation and atomic positions after simulation;
the structure change determining unit 407, when determining whether the structure of the crystal model can be changed, specifically includes: calculating the displacement of each atom in the first time threshold according to the atom position of each atom in the crystal model before simulation and the atom position after simulation; judging whether the maximum displacement in all atoms is larger than a set displacement threshold value; if yes, determining that the structure of the crystal model can be changed; otherwise, it is determined that the structure of the crystal model does not change.
In one embodiment of the present invention, the simulation unit 406 is further configured to determine the structure of the crystal model after dislocation slip as a new crystal model after performing the slip process for simulating the dislocation in the crystal model, and trigger the selection unit 403, the second determination unit 404, the simulation data acquisition unit 405, the structure change judgment unit 407, and the simulation unit 406 to perform corresponding operations again by using the new crystal model to continue simulating the slip process for simulating the dislocation in the crystal model when the next electron hits the dislocation.
In one embodiment of the present invention, referring to fig. 6, the apparatus further includes: and a display unit 408 for visually displaying the slip process of the dislocation in the crystal model by using a visual software.
It will be appreciated that the structure illustrated in the embodiments of the present invention is not intended to be limiting in any particular way for a molecular dynamics simulation apparatus for the action of electron impact dislocations. In other embodiments of the invention, a molecular dynamics simulation apparatus of electron impact dislocation action may include more or less components than illustrated, or certain components may be combined, or certain components may be split, or different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.
The content of information interaction and execution process between the modules in the device is based on the same conception as the embodiment of the method of the present invention, and specific content can be referred to the description in the embodiment of the method of the present invention, which is not repeated here.
The embodiment of the invention also provides electronic equipment, which comprises a memory and a processor, wherein the memory stores a computer program, and the processor realizes the molecular dynamics simulation method of the electron impact dislocation effect in any embodiment of the invention when executing the computer program.
Embodiments of the present invention also provide a computer readable storage medium having a computer program stored thereon, which when executed by a processor causes the processor to perform a molecular dynamics simulation method of electron impact dislocation action in any of the embodiments of the present invention.
Specifically, a system or apparatus provided with a storage medium on which a software program code realizing the functions of any of the above embodiments is stored, and a computer (or CPU or MPU) of the system or apparatus may be caused to read out and execute the program code stored in the storage medium.
In this case, the program code itself read from the storage medium may realize the functions of any of the above-described embodiments, and thus the program code and the storage medium storing the program code form part of the present invention.
Examples of the storage medium for providing the program code include a floppy disk, a hard disk, a magneto-optical disk, an optical disk (e.g., CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a nonvolatile memory card, and a ROM. Alternatively, the program code may be downloaded from a server computer by a communication network.
Further, it should be apparent that the functions of any of the above-described embodiments may be implemented not only by executing the program code read out by the computer, but also by causing an operating system or the like operating on the computer to perform part or all of the actual operations based on the instructions of the program code.
Further, it is understood that the program code read out by the storage medium is written into a memory provided in an expansion board inserted into a computer or into a memory provided in an expansion module connected to the computer, and then a CPU or the like mounted on the expansion board or the expansion module is caused to perform part and all of actual operations based on instructions of the program code, thereby realizing the functions of any of the above embodiments.
It is noted that relational terms such as first and second, and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one …" does not exclude the presence of additional identical elements in a process, method, article or apparatus that comprises the element.
Those of ordinary skill in the art will appreciate that: all or part of the steps for implementing the above method embodiments may be implemented by hardware related to program instructions, and the foregoing program may be stored in a computer readable storage medium, where the program, when executed, performs steps including the above method embodiments; and the aforementioned storage medium includes: various media in which program code may be stored, such as ROM, RAM, magnetic or optical disks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A molecular dynamics simulation method of electron impact dislocation, comprising:
s1, establishing a crystal model to be simulated by using molecular dynamics simulation software; the surface of the crystal model includes at least one dislocation;
s2, determining the incident energy of electrons;
s3, randomly selecting at least one scattering angle in a preset scattering angle range;
s4, determining a speed vector acquired by the impacted atoms when the electrons impact the dislocation and scatter at the selected scattering angle according to the incidence energy when the electrons impact the dislocation in the dislocation area of the crystal model according to the incidence energy;
s5, inputting the determined at least one speed vector into the molecular dynamics simulation software to obtain simulation data for simulating all atomic states in the crystal model after the molecular dynamics simulation software endows at least one speed vector to at least one target atom in a one-to-one correspondence manner; the target atoms are positioned in the dislocation area;
s6, simulating the slip process of dislocation in the crystal model according to the simulation data.
2. The method of claim 1, wherein determining, based on the incident energy, a velocity vector acquired by the impinging atoms when electrons are scattered at a selected scattering angle after impinging the dislocations when the electrons impinge on the dislocation region of the crystal model, comprises:
based on the principle of energy conservation and the incident energy, determining energy transferred to the impacted atoms when electrons impact the dislocation and scatter at a selected scattering angle when the electrons impact the dislocation when entering the dislocation area of the crystal model;
determining the speed of electrons after scattering and the speed obtained by the impacted atoms according to the energy of the impacted atoms;
determining a scattering angle of the impacted atom based on the velocity of the electrons after scattering, the velocity obtained by the impacted atom, and the scattering angle;
randomly generating an azimuth angle within a preset azimuth angle range, and calculating a speed vector acquired by the impacted atom based on the randomly generated azimuth angle and the scattering angle of the impacted atom.
3. The method of claim 1, further comprising, after said obtaining simulation data for all atomic states in said crystal model after assigning at least one velocity vector to at least one target atom in a one-to-one correspondence by said molecular dynamics simulation software:
determining each atom positioned in the dislocation position area based on the crystal model established by the molecular dynamics simulation software;
at least one target atom with the same number as the velocity vector is randomly selected from the atoms in the dislocation region, and information of the at least one target atom is input into the molecular dynamics simulation software.
4. The method according to claim 1, characterized in that prior to step S6, further comprising:
s50, judging whether the structure of the crystal model can be changed according to simulation data corresponding to the condition that the molecular dynamics simulation software simulates all the atomic states in the crystal model to reach a set first time threshold;
if the judgment result is yes, executing the slip process of dislocation in the crystal model according to the simulation data corresponding to the condition that the simulation of all the atomic states in the crystal model is carried out by the molecular dynamics simulation software and reaches the set second time threshold; the second time threshold is greater than the first time threshold;
and if not, triggering the molecular dynamics simulation software to stop simulation, and returning to execute S3, S4, S5 and S50.
5. The method of claim 4, wherein the analog data comprises: atomic positions before simulation and atomic positions after simulation;
the judging whether the structure of the crystal model can be changed comprises the following steps:
calculating the displacement of each atom in the first time threshold according to the atom position of each atom in the crystal model before simulation and the atom position after simulation;
judging whether the maximum displacement in all atoms is larger than a set displacement threshold value; if yes, determining that the structure of the crystal model can be changed; otherwise, it is determined that the structure of the crystal model does not change.
6. The method of claim 4, further comprising, after performing the slip process simulating dislocations in the crystal model based on simulation data corresponding to when all atomic states in the crystal model are simulated in accordance with the molecular dynamics simulation software to reach a set second time threshold:
the structure of the crystal model after dislocation slip is determined as a new crystal model, and S3, S4, S5, S50 and S6 are performed back using the new crystal model to continue the slip process of dislocations in the crystal model when the next electron hits the dislocation.
7. The method of any one of claims 1-6, wherein the slip process of dislocations in the crystal model is visualized using visualization software.
8. A molecular dynamics simulation apparatus for electron impact dislocation, comprising:
the crystal model building unit is used for building a crystal model to be simulated by utilizing molecular dynamics simulation software; the surface of the crystal model includes at least one dislocation;
a first determining unit for determining an incident energy of electrons;
a selection unit for randomly selecting at least one scattering angle within a preset scattering angle range;
a second determining unit configured to determine, for each randomly selected scattering angle, a velocity vector acquired by an impacted atom when the electron is scattered at the selected scattering angle after striking the dislocation when the electron is incident to a region where the dislocation of the crystal model is located, according to the incident energy;
the simulation data acquisition unit is used for inputting the determined at least one speed vector into the molecular dynamics simulation software to acquire simulation data for simulating all atomic states in the crystal model after the molecular dynamics simulation software endows at least one speed vector to at least one target atom in a one-to-one correspondence manner; the target atoms are positioned in the dislocation area;
and the simulation unit is used for simulating the slip process of dislocation in the crystal model according to the simulation data.
9. An electronic device comprising a memory and a processor, the memory having stored therein a computer program, the processor implementing the method of any of claims 1-7 when the computer program is executed.
10. A computer readable storage medium having stored thereon a computer program which, when executed in a computer, causes the computer to perform the method of any of claims 1-7.
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