A method for calculating the dislocation structure energy based on discrete dislocation dynamics

Abstract

The present invention relates to a method for calculating the dislocation structure energy based on discrete dislocation dynamics. This method decomposes the strain and stress generated by plastic deformation inside the crystal into the elastic field generated by dislocations in an infinite continuous medium and an additional field for correcting the real boundary conditions, and can accurately capture the stress and strain states of the target crystal material under actual plastic deformation conditions, thereby deeply reflecting the influence of the real boundary on the plastic deformation process. By directly considering the dynamic evolution of a large number of discrete dislocation segments through the discrete dislocation dynamics theory to simulate the plastic behavior of materials in essence, it can directly capture the evolution process of the dislocation substructure, reproduce the plastic deformation mechanism of materials in essence, and then derive the calculation formula for the dislocation structure energy, improve the calculation accuracy of the dislocation structure energy, and enable a deeper understanding of the internal mechanism of different plastic deformation behaviors of crystal materials.

Description

Technical Field

[0001] The present invention relates to the field of materials science, and particularly relates to a method for calculating the dislocation structure energy based on discrete dislocation dynamics. Background Art

[0002] Dislocation structures play a key role in the generation of crystal defects such as twinning nucleation, fatigue crack initiation and propagation. The irreversibility of crack propagation stems from the dissipation generated by dislocation motion, and crack propagation is the result of the evolution of the dislocation structure near the crack tip. Therefore, it is crucial to quantify the contribution of dislocation structures to plastic deformation and even fatigue failure.

[0003] During the plastic deformation of metals, most of the plastic work is dissipated in the form of heat, sound, etc., and the rest is stored in the material. The stored energy includes recoverable elastic strain energy and undissipated plastic work. In the absence of deformation damage, the undissipated plastic work includes the energy associated with individual isolated dislocations (dislocation line energy) and the dislocation structure energy generated by the interaction between dislocations. The dislocation structure energy is mainly caused by the change in lattice curvature induced by geometrically necessary dislocations, is elastically stored inside the material, is the result of the interaction of dislocation stress fields, and is also a supplement to the sum of all dislocation line energies.

[0004] Existing methods for calculating the dislocation structure energy are mainly based on crystal plasticity finite element theory, and the consideration of dislocations is based on statistical average theory, which has a certain phenomenological nature in mathematical description and cannot consider the discreteness and randomness of dislocation motion at the microstructural scale and their influence on the plastic deformation of crystal materials. Summary of the Invention

[0005] The purpose of this part is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this part, as well as in the abstract and title of the present application, to avoid obscuring the purpose of this part, the abstract and the title, and such simplifications or omissions shall not be used to limit the scope of the present invention.

[0006] In view of the above and / or problems existing in the prior art, the present invention is proposed.

[0007] As a preferred embodiment of the present invention, the present invention provides a method for calculating the dislocation structure energy based on discrete dislocation dynamics, including: obtaining the crystallographic information of the target crystal material and constructing a discrete dislocation dynamics geometric model of the target crystal material; based on the geometric model and the dislocation evolution mechanism, simulating the dynamic evolution process of dislocations in the target crystal material during plastic deformation; the dynamic evolution process is used to describe the dynamic distribution and morphological changes of dislocations in the target crystal material; based on the discrete dynamics theory, decomposing the stress and strain caused by plastic deformation of the target crystal material into the elastic field generated by dislocations in an infinitely large continuous medium and an additional field for correcting the real boundary conditions, so as to obtain the stress and strain generated during the actual plastic deformation of the target crystal material; according to the obtained stress and strain generated during the actual plastic deformation of the target crystal material, using the free energy calculation formula to deduce the dislocation structure energy in the target crystal material.

[0008] In some possible implementation manners, based on the geometric model and the dislocation evolution mechanism, simulating the dynamic evolution process of dislocations in the target crystal material during plastic deformation includes: determining the initial dislocation configuration of the target crystal material and applying a preset resolved shear stress to the discrete dislocation dynamics model ; when the resolved shear stress exceeds the preset time of the dislocation source strength, an edge dislocation with a Burgers vector of nucleates from the dislocation source and continues to slide along the corresponding slip plane, and the dislocation nucleation time is:

[0009] ;

[0010] where is a constant related to the dislocation drag coefficient, is the length of the dislocation source. When the attractive force between dislocations is balanced with the applied resolved shear stress , the diameter of the initial dislocation loop is:

[0011] ;

[0012] where G is the shear modulus, v is the Poisson's ratio, is the dislocation source strength, and the dislocation source strength value is obtained from experimental data. The sliding speed of the dislocation between pinning obstacles is:

[0013] ;

[0014] where, is the Boltzmann constant, is the representative distance of cooperative dislocation slip, is the atomic vacancy volume is the equilibrium concentration of vacancies at temperature , and is the vacancy diffusion coefficient.

[0015] In some possible implementations, the stress and strain generated during the actual plastic deformation of the target crystal material are respectively the superposition of the corresponding elastic field and additional field; the strain generated during the actual plastic deformation is expressed as:

[0016] ;

[0017] where is the actual strain, is the strain field of dislocations, is the additional field of strain; the stress generated during the actual plastic deformation is expressed as:

[0018] ;

[0019] where is the actual stress, is the stress field of dislocations, is the additional field of stress.

[0020] In some possible implementations, the additional field is solved by numerical analysis methods, including but not limited to the finite element method, boundary element method, or discrete element method; the elastic field is calculated using the theory of elasticity, specifically the superposition of the elastic fields of all dislocations; where is expressed as:

[0021] ;

[0022] where represents the -th dislocation, N represents the number of dislocations, represents the strain of the elastic field of the -th dislocation; is expressed as:

[0023] ;

[0024] where represents the stress of the elastic field of the -th dislocation.

[0025] In some possible implementations, the stress of the elastic field of the -th dislocation is expressed as:

[0026] ;

[0027] where:

[0028] ;

[0029] ;

[0030] ;

[0031] wherein, is the shear modulus, is the Burgers vector, is the Poisson's ratio, , is the coordinate of the current dislocation in the local coordinate system; the elastic field strain of the -th dislocation is expressed as:

[0032] ;

[0033] where:

[0034] ;

[0035] ;

[0036] .

[0037] In some possible implementation manners, the free energy calculation formula is expressed as:

[0038] ;

[0039] According to the stress and strain generated during the actual plastic deformation of the obtained target crystal material, the dislocation structure energy in the target crystal material is deduced by using the free energy calculation formula, including: the free energy during the plastic deformation process is composed of the stored energy related to dislocations and the elastic stored energy ; is the sum of the dislocation strain energy and the dislocation structure energy , that is, the free energy is expressed as:

[0040] ;

[0041] Due to the singularity of the dislocation stress-strain field, the free energy is further determined according to the free energy calculation formula as:

[0042] ;

[0043] wherein, the elastic stored energy related to remote loading is expressed as:

[0044] ;

[0045] wherein, and are the stress field and strain field respectively when the same external force is applied to a pure elastic body with the same geometric shape; that is, the dislocation structure energy is expressed as:

[0046] .

[0047] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0048] The present invention provides a method for calculating dislocation structure energy based on the discrete dislocation dynamics theory. By constructing a geometric model of the target crystal material and dynamically simulating the evolution process of dislocations in plastic deformation, the dynamic distribution and morphological changes of dislocations are accurately described. The strain and stress generated by plastic deformation inside the crystal are decomposed into the elastic field generated by dislocations in an infinite continuous medium and an additional field for correcting the real boundary conditions, which can accurately capture the stress and strain states of the target crystal material under actual plastic deformation conditions, thereby profoundly reflecting the influence of the real boundary on the plastic deformation process. By directly considering the dynamic evolution of a large number of discrete dislocation segments through the discrete dislocation dynamics theory to simulate the plastic behavior of materials essentially, the evolution process of dislocation substructures can be directly captured, the plastic deformation mechanism of materials can be reproduced essentially, and then the calculation formula of dislocation structure energy is derived, improving the calculation accuracy of dislocation structure energy and enabling a deeper understanding of the internal mechanism of different plastic deformation behaviors of crystal materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention, the drawings required for the embodiments of the present invention will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0050] Figure 1 It is a schematic flowchart of an embodiment of a method for calculating dislocation structure energy based on discrete dislocation dynamics provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0052] In the relevant descriptions of this embodiment, terms such as "include, contain, have" are all open terms, and generally should be preferably understood as including but not limited to; the term "at least one" is generally preferably understood as one or more, where "multiple" means two or more; the term "at least one of the following items (pieces)" or its similar expressions refer to any combination of these items, including any combination of single items (pieces) or plural items (pieces). For example, "at least one of a, b or c", or, "at least one of a, b and c" can all represent: a, b, c, a - b (that is, a and b), a - c, b - c, or a - b - c, where a, b, c can be single or multiple respectively; the symbol "A / B" is used to describe the selection relationship of associated objects, and generally represents an "or" relationship before and after.

[0053] In the following descriptions of this embodiment, the terms used in the embodiments of this application are only for the purpose of describing specific embodiments, and are not intended to limit this application. The singular forms "a" and "the" used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0054] Those skilled in the art should understand that in the following descriptions of the embodiments of this application, the sequence numbers do not mean the sequence of execution, and some or all steps can be executed in parallel or sequentially. The execution sequence of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of this application.

[0055] Those skilled in the art should understand that the numerical ranges in the embodiments of this application should be understood as specifically disclosing each intermediate value between the upper and lower limits of the range. The intermediate values within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the range, are also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0056] Unless otherwise specified, the technical / scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs. Although this application only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of this application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0057] In order to illustrate the technical solutions of the present invention, specific embodiments will be used for illustration below.

[0058] Dislocation structures play a crucial role in the generation of crystal defects such as twinning nucleation, fatigue crack initiation and propagation. The irreversibility of crack propagation stems from the dissipation generated by dislocation motion, and crack propagation is the result of the evolution of dislocation structures near the crack tip. Therefore, it is crucial to quantify the contribution of dislocation structures to plastic deformation and even fatigue failure.

[0059] During the plastic deformation of metals, most of the plastic work is dissipated in the form of heat, sound, etc., and the rest is stored in the material. The stored energy includes recoverable elastic strain energy and undissipated plastic work. In the absence of deformation damage, the undissipated plastic work includes the energy associated with individual isolated dislocations (dislocation line energy) and the dislocation structure energy generated by the interaction between dislocations. The dislocation structure energy is mainly caused by the change in lattice curvature induced by geometrically necessary dislocations, is elastically stored inside the material, is the result of the interaction of dislocation stress fields, and is also a supplement to the sum of all dislocation line energies.

[0060] Existing methods for calculating dislocation structure energy are mainly based on crystal plasticity finite element theory, and the consideration of dislocations is based on statistical average theory, which has a certain phenomenological nature in mathematical description and cannot consider the discreteness and randomness of dislocation motion at the microstructural scale on the plastic deformation of crystal materials.

[0061] The discrete dislocation dynamics theory simulates the plastic behavior of materials by directly considering the dynamic evolution of a large number of discrete dislocation segments, and can directly capture the evolution process of dislocation substructures. Therefore, it has a natural advantage in calculating dislocation structure energy and can more deeply understand the internal mechanism of different plastic deformation behaviors of crystal materials.

[0062] Figure 1 The following is a schematic flow chart of an embodiment of a method for calculating dislocation structure energy based on discrete dislocation dynamics provided by an embodiment of the present invention. Refer to Figure 1 As shown, the above method may include:

[0063] S101, obtain the crystallographic information of the target crystal material and construct a discrete dislocation dynamics geometric model of the target crystal material;

[0064] Among them, the target crystal material is the crystal material to be studied, and the target crystal material can be any material that can produce plastic deformation, such as metals (such as magnesium alloys, zirconium alloys), semiconductors, etc. Determining the crystallographic information of the target crystal material includes determining its specific chemical composition, possible structure types, crystal orientations and other information. For example, the crystallographic information of the target crystal material can be found by using crystallographic databases and literature resources, or can also be actually measured by detection equipment, such as Electron Backscatter Diffraction (EBSD), etc.

[0065] Discrete Dislocation Dynamics (DDD) is a branch of dislocation dynamics that uses a discretization method to simulate the behavior of dislocations in crystals. Dislocations are important defects in crystals, resulting from the disorder of atomic arrangements, and have a significant impact on the physical and mechanical properties of materials.

[0066] According to the crystallographic information of the obtained target crystal material, a geometric model of the target crystal material is constructed using computer simulation software (such as MaterialsStudio, Vesta, etc.). In the model, the unit cell structure of the crystal, atomic arrangement, and possible defects (such as vacancies, dislocations, etc.) can be represented. In DDD simulations, the initial conditions of dislocations need to be set, including the type of dislocations (such as edge dislocations, screw dislocations, etc.), position, direction, and quantity. These initial conditions will affect the dynamic evolution of dislocations and the plastic deformation behavior of the crystal material. The constructed geometric model is simulated using DDD simulation software.

[0067] S102, based on the geometric model and the dislocation evolution mechanism, simulate the dynamic evolution process of dislocations in the target crystal material during plastic deformation; the dynamic evolution process is used to describe the dynamic distribution and morphological changes of dislocations in the target crystal material;

[0068] It should be noted that the dislocation evolution mechanism includes but is not limited to dislocation multiplication, dislocation movement, interaction, annihilation, etc. Based on different target materials, there are corresponding dislocation evolution mechanisms.

[0069] For example, the dislocation multiplication mechanism can include the Frank-Read dislocation source mechanism. Under the action of an external load, dislocations will move inside the crystal. This movement is affected by various factors, including the stress field, temperature, interaction between dislocations, etc. The movement speed of dislocations can be described by dislocation dynamics equations, which can be based on the principles of continuum mechanics and statistical mechanics. Under the action of the Frank-Read dislocation source mechanism, dislocations can multiply inside the crystal. When the resolved shear stress exceeds a certain threshold, new dislocations will nucleate from the dislocation source and expand along the slip plane. At the same time, interactions between dislocations may also lead to annihilation (such as dislocation cancellation, dislocation recombination, etc.).

[0070] In some embodiments, the above step S102 may specifically include:

[0071] Determine the initial dislocation configuration of the target crystal material, specifically, it is necessary to clarify the dislocation distribution of the target crystal material at the beginning of the simulation, including the position, type (such as edge dislocation, screw dislocation), Burgers vector, etc. of the dislocations.

[0072] Apply a preset resolved shear stress to the discrete dislocation dynamics model ; This stress is the main external factor driving the movement of dislocations. The magnitude of the preset resolved shear stress can be determined based on the physical properties of the target material, experimental data, simulation requirements, and possible theoretical models or empirical judgments, and is used to simulate the influence of actual external loads on the movement of dislocations within the material.

[0073] When the resolved shear stress exceeds the preset time of the dislocation source strength, an edge dislocation with a Burgers vector of nucleates from the dislocation source and continues to slide along the corresponding slip plane. The dislocation nucleation time is:

[0074] ;

[0075] where is a constant related to the dislocation drag coefficient, is the length of the dislocation source. When the attraction between dislocations is balanced with the applied resolved shear stress , the diameter 𝐿 of the initial dislocation loop is:

[0076] ;

[0077] where G is the shear modulus, v is the Poisson's ratio, is the dislocation source strength, and the dislocation source strength value is obtained from experimental data. The sliding speed of the dislocation between pinning obstacles is:

[0078] .

[0079] Among them, is the Boltzmann constant, is the representative distance of cooperative dislocation slip, is the atomic vacancy volume, is the temperature at the equilibrium vacancy concentration, is the vacancy diffusion coefficient.

[0080] It is understandable that using the above basic parameters such as the Boltzmann constant, the representative distance of cooperative dislocation slip, the atomic vacancy volume, the equilibrium vacancy concentration at a certain temperature, and the vacancy diffusion coefficient to calculate the slip velocity of dislocations between pinning obstacles has clear physical significance and a solid theoretical basis (for example, the Boltzmann constant is related to thermodynamics, and the vacancy diffusion coefficient describes the diffusion rate of vacancies in materials. These parameters together determine the dynamic behavior of dislocations between pinning obstacles). These parameters are not only directly related to the dislocation slip mechanism, but also most of them can be measured or estimated by experimental means (for example, the vacancy diffusion coefficient can be obtained through diffusion experiments, and the equilibrium vacancy concentration can be obtained through thermodynamic calculations. This makes this method feasible in practical applications). Therefore, the above calculation method has a wider scope of application in practical applications, and it can be applied to various types of materials and conditions. Whether it is metal, ceramic or polymer material, as long as the relevant parameters can be obtained, this method can be used for calculation. In addition, this method is also applicable to the calculation of dislocation slip velocity under different temperature, pressure and stress conditions. Compared with only using macroscopic mechanical property parameters, these basic parameters reveal the microscopic mechanism of dislocation slip more deeply, thus providing more accurate and reliable calculation results.

[0081] It should be noted that after determining the dislocation nucleation time among the above parameters , the position where dislocations are generated in the target crystal material can be further determined. Then, by calculating the above initial dislocation loop diameter , the size of the dislocations can be determined. Finally, by determining the slip velocity of dislocations between pinning obstacles , the movement direction of dislocations when they expand along the slip plane can be determined. In this way, through the calculation of the above parameters, the dynamic evolution of dislocations in the target crystal material can be described, and the dynamic evolution process of dislocations in the material can be simulated and described, including the multiplication, movement, interaction of dislocations and their influence on the macroscopic properties of the material.

[0082] S103, Based on the discrete dynamics theory, decompose the stress and strain caused by plastic deformation of the target crystal material into the elastic field generated by dislocations in an infinitely large continuous medium and the additional field for correcting the real boundary conditions, so as to obtain the stress and strain generated during the actual plastic deformation of the target crystal material;

[0083] Specifically, in some embodiments, the stress and strain generated during the actual plastic deformation of the target crystal material are respectively the superposition of the corresponding elastic field and the additional field;

[0084] At this time, the strain generated during the actual plastic deformation is expressed as:

[0085] ;

[0086] Among them, is the actual strain, is the strain field of the dislocation, is the additional field of the strain;

[0087] Similar to the strain, the stress generated during actual plastic deformation is expressed as:

[0088] ;

[0089] where, is the actual stress, is the stress field of the dislocation, is the additional field of the stress.

[0090] In some embodiments, the additional field can be solved by numerical analysis methods, including but not limited to the finite element method, the boundary element method, or the discrete element method, etc.;

[0091] In some embodiments, the elastic field is calculated using the theory of elasticity, specifically as the superposition of the elastic fields of all dislocations;

[0092] where, is expressed as:

[0093] ;

[0094] where, represents the th dislocation, N represents the number of dislocations, represents the th elastic field strain of the dislocation;

[0095] is expressed as:

[0096] ;

[0097] where, represents the th elastic field stress of the dislocation.

[0098] In some embodiments, the elastic field stress of the th dislocation is expressed as:

[0099] ;

[0100] where:

[0101] ;

[0102] ;

[0103] ;

[0104] Among them, is the shear modulus, is the Burgers vector, is the Poisson's ratio, , is the coordinate of the current dislocation in the local coordinate system;

[0105] The elastic field strain of the nth dislocation is expressed as:

[0106] ;

[0107] Among them:

[0108] ;

[0109] ;

[0110] .

[0111] S104. According to the stress and strain generated during the actual plastic deformation of the obtained target crystal material, the dislocation structure energy in the target crystal material is deduced using the free energy calculation formula.

[0112] In some embodiments, the free energy calculation formula can be expressed as:

[0113] ;

[0114] It can be further deduced as:

[0115] ;

[0116] It should be noted that since the free energy during the plastic deformation process is usually composed of the stored energy related to dislocations and the elastic stored energy , and is the sum of the dislocation strain energy and the dislocation structure energy , that is, the free energy can also be expressed as:

[0117] .

[0118] Due to the singularity of the dislocation stress-strain field, it is difficult to obtain a finite value for the free energy. Therefore, the free energy can be further determined as:

[0119] .

[0120] The elastic stored energy related to remote loading can be expressed as:

[0121] ;

[0122] Among them, and are the stress field and strain field respectively when the same external force is applied to pure elastomers with the same geometric shape. Therefore, the dislocation structure energy is deduced as:

[0123] .

[0124] In this way, the calculation of the dislocation structure energy in the target crystal material based on discrete dislocation dynamics is realized. Compared with the traditional statistical average method, the discrete dislocation dynamics model provides higher calculation accuracy. It can directly consider complex processes such as the interaction between dislocations, the multiplication and annihilation of dislocations, etc., so as to quantitatively analyze their contributions to plastic deformation, and can more deeply understand the internal mechanism of different plastic deformation behaviors of crystal materials, making the calculated dislocation structure energy closer to the real situation. This is of great significance for predicting the mechanical properties of materials, evaluating the reliability of materials and optimizing the design. And through the calculation of the dislocation structure energy, the behavior of crystal materials under different plastic deformation conditions can be understood more deeply. For example, the effects of different loading paths, temperatures, strain rates, etc. on the dislocation structure and energy distribution can be analyzed, so as to reveal how these factors affect the plastic deformation ability and failure mechanism of materials, etc.

[0125] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, reference can be made to each other. The key points of each embodiment are to illustrate the differences from other embodiments.

[0126] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting the present application; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the present application.

Claims

1. A method for calculating the dislocation structure energy based on discrete dislocation dynamics, characterized in that Including: Obtain the crystallographic information of the target crystal material and construct a discrete dislocation dynamics geometric model of the target crystal material; Based on the geometric model and the dislocation evolution mechanism, simulate the dynamic evolution process of dislocations in the target crystal material during plastic deformation; The dynamic evolution process is used to describe the dynamic distribution and morphological changes of dislocations in the target crystal material, and the dynamic evolution process includes: Determine the initial dislocation configuration of the target crystal material, and apply a preset resolved shear stress to the discrete dislocation dynamics geometric model ; When the slitting stress exceeds the preset time of the dislocation source strength, an edge dislocation with a Burgers vector of nucleates from the dislocation source and continues to slide along the corresponding slip plane. The dislocation nucleation time is as follows: ； wherein is a constant related to the dislocation drag coefficient, is the length of the dislocation source. When the attractive force between dislocations is balanced with the applied resolved shear stress the diameter of the initial dislocation loop is: ； Among them G is the shear modulus, v is the Poisson's ratio, is the dislocation source strength, and the dislocation source strength value is obtained from experimental data. The sliding speed of dislocations between pinning obstacles is as follows: ； Among them, is the Boltzmann constant, is the representative distance of cooperative dislocation slip, is the atomic vacancy volume, is the temperature is the equilibrium vacancy concentration at is the vacancy diffusion coefficient; Based on the discrete dynamics theory, decompose the stress and strain caused by plastic deformation of the target crystal material into the elastic field generated by dislocations in an infinitely large continuous medium and the additional field for correcting the real boundary conditions, and obtain the stress and strain generated during the actual plastic deformation of the target crystal material; According to the obtained stress and strain generated during the actual plastic deformation of the target crystal material, use the free energy calculation formula to deduce the dislocation structure energy in the target crystal material, including: The free energy calculation formula is expressed as: ； Free energy during the plastic deformation process Composed of the stored energy associated with dislocations and the elastic stored energy It consists of the dislocation strain energy and the dislocation structure energy The sum of which, that is, the free energy is expressed as: ； Due to the singularity of the dislocation stress-strain field, further determine the free energy according to the free energy calculation formula as: ； Among them, the elastic stored energy related to remote loading is expressed as: ； Among them, is the actual strain, is the actual stress, is the strain field of dislocations, is the additional field of strain, is the stress field of dislocations, is the additional field of stress, N is the number of dislocations, and are the stress field and strain field respectively when the same external force is applied to a pure elastic body with the same geometry; that is, the dislocation structure energy is expressed as: 。 2. The method according to claim 1, wherein The stress and strain generated during the actual plastic deformation of the target crystal material are respectively the superposition of the corresponding elastic field and additional field; The strain generated during actual plastic deformation is expressed as: ； The stress generated during actual plastic deformation is expressed as: 。 3. The method according to claim 2, wherein The additional field is solved by numerical analysis methods, including but not limited to the finite element method, boundary element method or discrete element method; The elastic field is calculated using the theory of elasticity, specifically the superposition of the elastic fields of all dislocations; Among them, It is expressed as: ； Among them, represents the ninth dislocation, represents the strain of the elastic field of the ninth dislocation; Expressed as: ； Among them, represents the elastic field stress of the nth edge dislocation.

4. The method according to claim 3, wherein, The elastic field stress of a single dislocation is expressed as: ； Among them: ； ； ； Among them, is the shear modulus, is the Burgers vector, is the Poisson's ratio, , is the coordinate of the current dislocation in the local coordinate system; Article The strain of the elastic field of a single dislocation is expressed as: ； Among them: ； 。

Images