Method for predicting slippage position of spiral dislocation of material
By determining the parameters relating the slip motion of irradiation defects and helical dislocations and using the dynamic Monte Carlo algorithm, helical dislocations are segmented into dislocation segments. The occurrence and diffusion probabilities of twist pairs are calculated, solving the problem that existing technologies cannot fully consider the influence of irradiation defects. This improves the accuracy of describing the slip behavior of helical dislocations and enables the study of the mechanical properties of materials.
Patent Information
- Application Number
- CN202411398355.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-08
- Publication Date
- 2025-11-04
AI Technical Summary
Existing research methods cannot fully consider the impact of irradiation defects on the slip of helical dislocations, especially on the occurrence and diffusion of helical dislocation twist pairs, resulting in inaccurate research on the mechanical properties of materials.
By determining the slip motion relationship parameters between irradiation defects and spiral dislocations, the spiral dislocations are divided into multiple dislocation segments, and the occurrence and diffusion probabilities of twist pairs are calculated. The slip position of the spiral dislocations is simulated by combining the dynamic Monte Carlo algorithm.
This improves the accuracy of describing the slip behavior of helical dislocations and helps to better study the effects of irradiation on the mechanical properties of materials.
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Figure CN120895142A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of mechanical property research of reactor irradiated materials, and particularly relates to a method for predicting a slip position of a screw dislocation of a material. BACKGROUND
[0002] The statements herein are merely provided for background information of the present application and do not necessarily constitute the prior art.
[0003] The lattice kinetic Monte Carlo simulation method is commonly used to simulate the slip characteristics of the screw dislocation generated due to irradiation in a body-centered cubic structure metal material, and is of great significance for understanding the mechanical properties of the metal material after irradiation.
[0004] At present, the influence of irradiation defects on the slip behavior of screw dislocations is mainly studied by using molecular dynamics, dislocation dynamics and crystal plasticity finite element methods. However, these methods have many limitations. For example, the method using molecular dynamics mainly reveals the interaction mechanism between screw dislocations and irradiation defects from the atomic scale. Since the time and space scales simulated by molecular dynamics are limited, it cannot be widely applied. SUMMARY
[0005] A brief overview of the present application is given in the following to provide a basic understanding of some aspects of the present application. It should be understood that this overview is not an exhaustive overview of the present application. It is not intended to determine the key or important parts of the present application, nor to limit the scope of the present application. Its purpose is only to give some concepts in a simplified form as a prelude to the more detailed description discussed later.
[0006] Embodiments of the present application provide a method for predicting a slip position of a screw dislocation of a material, the material being irradiated, which comprises:
[0007] S1, determining a parameter of a slip motion relationship between irradiation defects generated after irradiation of a material and a screw dislocation in the material; S2, dividing the screw dislocation into a plurality of dislocation segments; S3, determining a first probability of occurrence of a kink pair on the screw dislocation caused by the irradiation defects generated due to irradiation of the material according to the parameter determined in the step S1; S4, determining a second probability of diffusion of the kink pair on the screw dislocation caused by the irradiation defects generated due to irradiation of the material according to the parameter determined in the step S1; S5, determining a type of each of the plurality of dislocation segments according to the first probability determined in the step S3 and the second probability determined in the step S4, the type including occurrence, diffusion, fixation or original slip of the kink pair; S6, determining a slip position of each of the plurality of dislocation segments of the screw dislocation according to the type of each of the dislocation segments determined in the step S5; and S7, determining a slip position of the screw dislocation according to the slip position of each of the dislocation segments determined in the step S6.
[0008] The method provided by the embodiments of the present application can determine the first probability of occurrence of the kink pair on the screw dislocation caused by the irradiation defects and the second probability of diffusion of the kink pair according to the parameter of the slip motion relationship between the irradiation defects and the screw dislocation, and then determine the type of each of the plurality of dislocation segments according to the determined first probability and second probability, and further determine the slip position of each of the dislocation segments according to the type of each of the dislocation segments, so as to determine the slip position of the screw dislocation. The method helps to fully consider the influence of the irradiation defects on the slip motion of the screw dislocation, thereby helping to improve the accuracy of the description of the irradiation influence on the slip behavior of the screw dislocation, and further helping to study the irradiation influence on the mechanical properties of the material.
[0009] These and other advantages of the present application will become more apparent in light of the following detailed description of preferred embodiments of the present application. BRIEF DESCRIPTION OF DRAWINGS
[0010] To further illustrate the above and other advantages and features of the present application, a specific embodiment of the present application is further described in detail below with reference to the accompanying drawings. The drawings, together with the following detailed description, form a part of the present specification and are included to further illustrate the present application. Elements having the same function and structure are denoted by the same reference signs. It should be understood that these drawings are only typical examples of the present application and should not be regarded as limiting the scope of the present application.
[0011] Figure 1 is a flowchart of a method for predicting a slip position of a screw dislocation of a material according to an embodiment of the present application;
[0012] Figure 2 is a curve of a slip position of a screw dislocation with time under different numbers of irradiation defects according to an embodiment of the present application;
[0013] Figure 3 is a curve of the slip position of the screw dislocation over time at different temperatures according to an embodiment of the present application;
[0014] Figure 4 is a schematic diagram of interaction between irradiation defects and screw dislocations according to an embodiment of the present application.
[0015] It should be noted that the accompanying drawings are not necessarily drawn to scale, but are merely intended to illustrate the idea. DETAILED DESCRIPTION
[0016] In the following, exemplary embodiments of the present application will be described with reference to the accompanying drawings. In the description, not all of the features of the actual implementation are described in order to make the description clear and brief. However, it should be appreciated that many implementation-specific decisions must be made in order to develop any such actual implementation, to achieve the developers' specific goals, such as compliance with system- and business-related constraints, which will vary from one implementation to another. Moreover, it should be appreciated that a development effort, to develop any such actual implementation, can be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
[0017] It should also be noted that, in the description, only the device structures and / or processing steps closely related to the scheme according to the present application are shown in the drawings, and other details not closely related to the present application are omitted, in order to avoid obscuring the present application with unnecessary details.
[0018] It should be noted that, unless otherwise defined, technical or scientific terms used in the present application should be understood as having the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.
[0019] In the description of embodiments of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified.
[0020] In the related art, if the method of dislocation dynamics and the method of crystal plasticity finite element are used to study the mechanical properties of materials, parameters characterizing the slip properties of screw dislocations need to be obtained. However, the method of dislocation dynamics and the method of crystal plasticity finite element currently used only consider the influence of irradiation defects on the effective shear stress of screw dislocations when considering the influence of irradiation defects on the slip of screw dislocations, and do not consider the influence of irradiation defects on the occurrence of kink pairs and the diffusion of kink pairs. Since screw dislocations have a special crystal structure, their slip motion is usually realized in two steps, i.e., the occurrence of kink pairs and the diffusion of kink pairs, therefore, the current research method is not applicable.
[0021] Embodiments of the present application provide a method for predicting the slip position of a screw dislocation of a material, the material in the embodiments of the present application is irradiated. Figure 1 , Figure 1 is a flowchart of the method for predicting the slip position of a screw dislocation of a material according to the embodiments of the present application, the method provided by the embodiments of the present application can include the following steps S1 to S7.
[0022] S1, determining a parameter of a slip motion relationship between an irradiation defect generated after the material is irradiated and a screw dislocation in the material.
[0023] S2, dividing the screw dislocation into a plurality of dislocation segments.
[0024] S3, determining a first probability of occurrence of a kink pair on the screw dislocation caused by the irradiation defect generated when the material is irradiated according to the parameter determined in the step S1.
[0025] S4, determining a second probability of diffusion of the kink pair on the screw dislocation caused by the irradiation defect generated when the material is irradiated according to the parameter determined in the step S1.
[0026] S5, determining a type of each of the plurality of dislocation segments according to the first probability determined in the step S3 and the second probability determined in the step S4, the type can include occurrence of the kink pair, diffusion, fixed immobility or original slip.
[0027] S6, determining a slip position of each of the plurality of dislocation segments of the screw dislocation according to the type of each of the dislocation segments determined in the step S5.
[0028] S7, determining the slip position of the screw dislocation according to the slip position of each of the dislocation segments determined in the step S6.
[0029] The method provided by the embodiments of the present application can determine the first probability of occurrence of the kink pair on the screw dislocation caused by the irradiation defect and the second probability of diffusion of the kink pair by the parameter of the slip motion relationship between the irradiation defect and the screw dislocation, and then determine the type of each of the plurality of dislocation segments according to the determined first probability and second probability, and further determine the slip position of each of the dislocation segments according to the type of each of the dislocation segments, so as to determine the slip position of the screw dislocation, which helps to fully consider the influence of the irradiation defect on the slip motion of the screw dislocation, thereby helping to improve the accuracy of the description of the irradiation influence on the slip behavior of the screw dislocation, and further helping to study the irradiation influence on the mechanical properties of the material.
[0030] In some embodiments, a Kinetic Monte Carlo (KMC) algorithm can be utilized to predict the effect of irradiation defects on the screw dislocation slip motion.
[0031] In some embodiments, the parameters of the relationship between the irradiation defects generated after irradiation and the screw dislocation slip motion in the material can be determined by initializing the simulation conditions.
[0032] In some embodiments, the parameters can include a critical shear stress increment value when the screw dislocation slips in the presence of irradiation defects and a critical shear stress increment value when the kink pairs on the screw dislocation diffuse in the presence of irradiation defects
[0033] In some embodiments, the parameters can also include the simulation time, temperature, applied stress, number of irradiation defects, etc. By setting different parameters, different slip motions of the screw dislocation can be simulated. Referring to Figure 2 , Figure 2 is a curve of the screw dislocation slip position over time according to different numbers of irradiation defects in embodiments of the present application, where curve a represents the screw dislocation slip position over time when the number of irradiation defects is 5, and curve e represents the screw dislocation slip position over time when the number of irradiation defects is 10. Referring to Figure 3 , Figure 3 is a curve of the screw dislocation slip position over time according to different temperatures in embodiments of the present application, where curve c represents the screw dislocation slip position over time when the number of irradiation defects is 10 and the temperature is 300 K, and curve d represents the screw dislocation slip position over time when the number of irradiation defects is 10 and the temperature is 600 K.
[0034] In some embodiments, in the S2 step, under the condition of an applied stress, the screw dislocation can be divided into multiple dislocation segments for slip.
[0035] In some embodiments, during the slip process, the part of the dislocation segment that does not encounter irradiation defects can remain unchanged and continue to slip. Referring to Figure 4 , Figure 4 is a schematic diagram of the interaction between irradiation defects and screw dislocations according to embodiments of the present application, where the part of the dislocation segment that encounters irradiation defects will stop slipping during the slip process. For the part of the dislocation segment that encounters irradiation defects, the type of the dislocation segment can include the occurrence of kink pairs, the diffusion of kink pairs, and being fixed.
[0036] In some embodiments, the parameter determined in the S1 step and the first probability satisfy the following expression (1):
[0037]
[0038] wherein r kp represents the first probability, v0 represents the attempt frequency, L represents the length of the dislocation segment, w represents the separation distance of the kink pairs, b represents the Burgers vector, ΔH0 represents the sum of the formation enthalpy of two kink pairs with opposite signs, p represents the first fitting parameter, q represents the second fitting parameter, k represents the Boltzmann constant, T represents the temperature, τ p represents the Peierls stress when the dislocation segment slips, τ represents the first stress component along different directions, τ' represents the second stress component along different directions, α0 represents the third fitting parameter, α1 represents the fourth fitting parameter, α2 represents the fifth fitting parameter, α3 represents the sixth fitting parameter, represents the critical shear stress increment value when the screw dislocation slips in the presence of irradiation defects.
[0039] The method provided by the embodiments of the present application is advantageous in more accurately determining the first probability of the occurrence of kink pairs on the screw dislocation in the presence of irradiation defects through the above expression (1).
[0040] In some embodiments, the first fitting parameter to the second fitting parameter can be obtained through simulation, and the parameter size is related to the type of material and is irrelevant to irradiation defects.
[0041] In some embodiments, the expression (1) can be obtained through the following expression (2) to expression (4):
[0042]
[0043] ΔH(σ) = ΔH0(1 - [θ(σ)] p ) q (3)
[0044]
[0045] wherein ΔH(σ) represents the activation enthalpy of the occurrence of kink pairs, σ represents the function of the local stress tensor, and θ(σ) represents the effective stress.
[0046] In some embodiments, the parameter determined in the S1 step and the second probability satisfy the following expression (5):
[0047]
[0048] wherein r skrepresents a second probability, v1 represents a second attempt frequency, k represents a Boltzmann constant, and T represents a temperature, represents a critical shear stress increment value when a kink pair on a screw dislocation diffuses.
[0049] The method provided by the embodiments of the present application can be used to more accurately determine the second probability of the diffusion of the kink pair on the screw dislocation when the irradiation defects exist, by using the above expression (5).
[0050] In some embodiments, the first attempt frequency v0 is different from the second attempt frequency v1.
[0051] In some embodiments, when the slipping dislocation segment encounters the irradiation defects, the movement of the dislocation segment is inhibited, and at this time, the type of the dislocation segment can include the appearance of the kink pair, the diffusion, or the fixation.
[0052] In some embodiments, whether the type of the dislocation segment is the appearance of the kink pair can be determined by the relative positions of the dislocation segment and the two adjacent dislocation segments and the first probability, and whether the type of the dislocation segment is the diffusion can be determined by the relative positions of the dislocation segment and the two adjacent dislocation segments and the second probability. When the dislocation segment encounters the irradiation defects and neither the first probability nor the second probability is satisfied, the type of the dislocation segment is the fixation.
[0053] In some embodiments, when the slipping dislocation segment does not encounter the irradiation defects, the type of the dislocation segment is to continue to slip in the original state.
[0054] In some embodiments, the slip speed of the dislocation segment in the type of keeping the original state and continuing to slip satisfies the following expression (6):
[0055]
[0056] wherein, v k represents the slip speed of the kink pair, τ b represents the stress when the dislocation segment keeps the original state and continues to slip, and B represents the slip friction coefficient.
[0057] In some embodiments, according to the slip speed of the dislocation segment in the type of keeping the original state and the set time, the slip position of the dislocation segment can be determined.
[0058] In some embodiments, the step S5 can include: S51, when the dislocation segment encounters the irradiation defects, determining, according to the position of the dislocation segment and the positions of the two adjacent dislocation segments, the first probability, and the second probability, that the type of the dislocation segment is the appearance of the kink pair, the diffusion, or the fixation; and S52, when the dislocation segment does not encounter the irradiation defects, determining that the type of the dislocation segment is the original state and continues to slip.
[0059] The method provided by the embodiments of the present application can improve the accuracy and efficiency of determining the type of dislocation segment, thereby improving the reliability of determining the slip position of each dislocation segment according to the type of the dislocation segment and finally determining the slip position of the screw dislocation.
[0060] In some embodiments, the step S51 can include: when the dislocation segment encounters the irradiation defect, determining whether the position of the dislocation segment and the positions of the two adjacent dislocation segments are consistent; when the position of the dislocation segment and the positions of the two adjacent dislocation segments are consistent, determining whether the first probability is satisfied, if the first probability is satisfied, determining that the type of the dislocation segment is the occurrence of kink pairs, and if the first probability is not satisfied, determining that the type of the dislocation segment is fixed; when the position of the dislocation segment and the positions of the two adjacent dislocation segments are not consistent, determining whether the second probability is satisfied, if the second probability is satisfied, determining that the type of the dislocation segment is diffusion, and if the second probability is not satisfied, determining that the type of the dislocation segment is fixed.
[0061] The method provided by the embodiments of the present application can further improve the accuracy of determining the type of dislocation segment.
[0062] In some embodiments, in the step S6, when the type of the dislocation segment is the occurrence of kink pairs, the slip position of the dislocation segment is the position of the previous moment plus a predetermined value.
[0063] In some embodiments, the predetermined value can be set according to experience.
[0064] In some embodiments, in the step S6, when the type of the dislocation segment is the diffusion of kink pairs, the slip positions of the two adjacent dislocation segments of the dislocation segment are consistent with the slip position of the dislocation segment.
[0065] In some embodiments, in the step S6, when the type of the dislocation segment is fixed, the slip position of the dislocation segment is the position of the previous moment.
[0066] In some embodiments, in the step S6, when the type of the dislocation segment is the original slip, the slip position of the dislocation segment is the position of the next moment.
[0067] The method provided by the embodiments of the present application can determine the slip position of the dislocation segment based on the slip position of the previous moment or the next moment of the dislocation segment, which is more accurate and faster.
[0068] For the embodiments of the present application, it should also be noted that the features of the embodiments of the present application and the embodiments can be combined with each other to obtain new embodiments without conflict.
[0069] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and the protection scope of the present application shall be subject to the protection scope of the claims.
Claims
1. A method of predicting the slip location of a screw dislocation in a material that has been irradiated, characterized in that, It comprises: S1, determining the parameters of the slip motion relationship between the irradiation defects generated after the material is irradiated and the screw dislocations in the material; S2, dividing the screw dislocations into a plurality of dislocation segments; S3, according to the parameters determined in the S1 step, determining the first probability of the occurrence of kink pairs on the screw dislocations due to the irradiation defects generated by the irradiation of the material; S4, according to the parameters determined in the S1 step, determining the second probability of the diffusion of kink pairs on the screw dislocations due to the irradiation defects generated by the irradiation of the material; S5, according to the first probability determined in the S3 step and the second probability determined in the S4 step, determining the type of each dislocation segment in the plurality of dislocation segments, the type including the occurrence, diffusion, fixation or original slip of kink pairs; S6, according to the type of each dislocation segment determined in the S5 step, determining the slip position of each dislocation segment in the plurality of dislocation segments of the screw dislocations; S7, according to the slip position of each dislocation segment determined in the S6 step, determining the slip position of the screw dislocations.
2. The method according to claim 1, wherein The parameters include: the critical shear stress increment value when the screw dislocations slip in the presence of the irradiation defects, and the critical shear stress increment value when the screw dislocations generate kink pairs and diffuse.
3. The method of claim 1, wherein, The parameters determined in the S1 step and the first probability satisfy the following expression: wherein r kp represents the first probability, v0 represents a first attempt frequency, L represents a length of a dislocation segment, w represents a separation distance of a kink pair, b represents a Burgers vector, AH0 represents a sum of formation enthalpies of two kink pairs with different signs, p represents a first fitting parameter, q represents a second fitting parameter, k represents a Boltzmann constant, T represents a temperature, τ p represents a Peierls stress when the dislocation segment slips, τ represents a first stress component along a different direction, τ' represents a second stress component along a different direction, a0 represents a third fitting parameter, a1 represents a fourth fitting parameter, a2 represents a fifth fitting parameter, a3 represents a sixth fitting parameter, represents a critical shear stress increment value when the screw dislocation slips in the presence of the irradiation defect.
4. The method of claim 1, wherein, The parameters determined in the S1 step and the second probability satisfy the following expression: wherein r sk represents the second probability, v1 represents a second attempt frequency, k represents a Boltzmann constant, T represents a temperature, represents a critical shear stress increment value at the time of diffusion of a kink pair generated on the spiral dislocation in the presence of the irradiation defect.
5. The method of claim 1, wherein, The S5 step comprises: S51, when the dislocation segment encounters the irradiation defects, according to the position of the dislocation segment and the positions of the adjacent two dislocation segments, the first probability and the second probability, determining the type of the dislocation segment as the occurrence, diffusion or fixation of kink pairs; S52: when the dislocation segment does not encounter irradiation defects, determining the type of the dislocation segment as original slip.
6. The method of claim 5, wherein, The S51 step comprises: When the dislocation segment encounters the irradiation defects, judging whether the position of the dislocation segment and the positions of the adjacent two dislocation segments are consistent; When the position of the dislocation segment and the positions of the adjacent two dislocation segments are consistent, judging whether the first probability is satisfied, if the first probability is satisfied, determining the type of the dislocation segment as the occurrence of kink pairs, if the first probability is not satisfied, determining the type of the dislocation segment as fixation; When the position of the dislocation segment and the positions of the adjacent two dislocation segments are not consistent, judging whether the second probability is satisfied, if the second probability is satisfied, determining the type of the dislocation segment as the diffusion of kink pairs, if the second probability is not satisfied, determining the type of the dislocation segment as fixation.
7. The method according to any one of claims 1 to 6, characterized in that, In the S6 step, When the type of the dislocation segment is the occurrence of kink pairs, the slip position of the dislocation segment is the position at the previous moment plus a predetermined value.
8. The method according to any one of claims 1 to 6, characterized in that, In the S6 step, When the type of the dislocation segment is the diffusion of kink pairs, the slip positions of the adjacent two dislocation segments are consistent with the slip position of the dislocation segment.
9. The method according to any one of claims 1 to 6, characterized in that, In the S6 step, When the type of the dislocation segment is fixed, the slip position of the dislocation segment is the position at the previous time.
10. The method according to any one of claims 1 to 6, characterized in that, In the S6 step, When the type of the dislocation segment is fixed, the slip position of the dislocation segment is the position at the previous time.