Simulation Method for Defects of Tungsten

Abstract

Embodiments of the present application relate to the field of computer materials science, and specifically relate to a method for simulating defects in tungsten metal. The defects are generated by irradiating tungsten metal with He ions and W ions. The simulation method includes the following steps: S1: Simulate the irradiation of tungsten metal with He ions and W ions; S2: Determine the position of the peak of the displacement damage of the tungsten metal after irradiation in step S1; S3: Determine the source term of the defect clusters in the tungsten metal at the peak position of the displacement damage; S4: Simplify the configuration space of the defect clusters; S5: Determine the reaction coefficients of different types of defect clusters; S6: Determine the concentration of the defect clusters during the irradiation time according to the source term, configuration space, and reaction coefficients; S7: Determine the simulation of the defects in tungsten metal according to the concentration. The simulation method provided by the embodiments of the present application is beneficial to improving the accuracy of simulating the defects in tungsten metal and is also beneficial to improving the efficiency of simulating the defects in tungsten metal.

Description

Technical Field

[0001] Embodiments of the present application relate to the field of computer materials science, and more particularly to a method for simulating defects in tungsten metal. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] Tungsten metal is an alternative material for the divertor and the first wall of a fusion reactor. Fusion reactions generate high-energy neutrons and helium ions, which irradiate tungsten metal, causing a large number of defects to form in the tungsten metal. These defects can lead to hardening and embrittlement of the tungsten metal, thereby affecting its service life.

[0004] To design tungsten metal for use in a fusion reactor, it is necessary to study the defects generated after irradiating tungsten metal with high-energy neutrons and helium ions. However, due to the lack of high-energy neutron generation equipment for fusion reactions, it is difficult to accurately study the defects generated in tungsten metal. Summary of the Invention

[0005] A brief overview of the present application is given below to provide a basic understanding of certain 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 identify the key or important parts of the present application, nor is it intended to limit the scope of the present application. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description to follow.

[0006] Embodiments of the present application provide a method for simulating defects in tungsten metal, where the defects are generated by irradiating tungsten metal with He ions and W ions. The simulation method provided by the embodiments of the present application includes the following steps: S1: Simulate the irradiation of tungsten metal with He ions and W ions; S2: Determine the position of the peak of the displacement damage in the tungsten metal after irradiation in step S1; S3: Determine the source term of the defect clusters in the tungsten metal at the peak position of the displacement damage; S4: Simplify the configuration space of the defect clusters; S5: Determine the reaction coefficients of different types of defect clusters; S6: Determine the concentration of the defect clusters during the irradiation time according to the source term, the configuration space, and the reaction coefficients; S7: Determine the simulation of the defects in the tungsten metal according to the concentration.

[0007] The simulation method provided by the embodiments of the present application can improve the accuracy of determining the concentration of defect clusters within the irradiation time by determining the peak position of displacement damage, the source term, the reaction coefficients of different types of defect clusters, and simplifying the configuration space of defect clusters. This is beneficial to improving the accuracy of simulating the defects in tungsten metal, and further beneficial to improving the accuracy of defect research on tungsten metal. At the same time, by simplifying the configuration space of defect clusters, the configuration space of defect clusters can be effectively simplified, reducing the number of defect clusters that need to be determined, which is beneficial to improving the efficiency of simulating the defects in tungsten metal. Description of the Drawings

[0008] Other objects and advantages of the present application will become apparent and can help to comprehensively understand the present application through the description of the embodiments of the present application with reference to the drawings below.

[0009] Figure 1 It is a schematic flow chart of the simulation method provided by the embodiments of the present application.

[0010] Figure 2 It is based on Figure 1 The schematic flow chart of determining the peak position of displacement damage of tungsten metal after irradiation of tungsten metal in step S1 according to the shown simulation method.

[0011] Figure 3 It is based on Figure 1 The schematic flow chart of determining the source term of defect clusters at the peak position of displacement damage after He ion irradiation of tungsten metal according to the shown simulation method.

[0012] Figure 4 It is based on Figure 1 The schematic flow chart of determining the source term of defect clusters at the peak position of displacement damage after W ion irradiation of tungsten metal according to the shown simulation method.

[0013] Figure 5 It is based on Figure 1 The schematic flow chart of simplifying the configuration space of defect clusters according to the shown simulation method.

[0014] Figure 6 It is using Figure 5 The schematic diagram of the configuration space obtained after simplifying the configuration space according to the shown flow.

[0015] Description of the Reference Numerals:

[0016] 51. Upper limit of the configuration space; 52. Lower limit of the configuration space; 53. Configuration space.

[0017] It should be noted that the drawings are not necessarily drawn to scale, but are only shown in a schematic manner that does not affect the understanding of the reader. Detailed Embodiments

[0018] In the following, exemplary embodiments of the present application will be described with reference to the accompanying drawings. For clarity and conciseness, not all features of the actual embodiments are described in the specification. However, it should be understood that many implementation-specific decisions must be made during the development of any such actual embodiment in order to achieve the specific goals of the developer, for example, to comply with those constraints related to the system and business, and these constraints may vary with different embodiments. In addition, it should also be understood that although the development work may be very complex and time-consuming, such development work is only a routine task for those skilled in the art who benefit from the content of the present application.

[0019] Here, it should also be noted that in order to avoid obscuring the present application with unnecessary details, only the device structures and / or processing steps closely related to the solution according to the present application are shown in the drawings, while other details less related to the present application are omitted.

[0020] The inventors of the present application have found that due to the lack of high-energy neutron generation equipment for fusion reactions, it is difficult to comprehensively study the defects generated in tungsten metal. Therefore, in order to comprehensively study the defects generated in tungsten metal, He ions and W ions are usually used to irradiate tungsten metal and the defects generated by the irradiation are simulated to study the defects of tungsten metal.

[0021] In the related art, in order to study the defects of tungsten metal, each defect in the configuration space of the defects needs to be simulated, resulting in a large number of defects to be simulated, and the simulation of the defects of tungsten metal takes a long time and has low efficiency.

[0022] To solve the above problems, an embodiment of the present application provides a method for simulating defects of tungsten metal, where the defects are generated by irradiating tungsten metal with He ions and W ions. Refer to Figure 1 , the simulation method provided by the embodiment of the present application may include the following steps: S1: Simulate the irradiation of tungsten metal with He ions and W ions; S2: Determine the position of the peak of the displacement damage of the tungsten metal after irradiation in step S1; S3: Determine the source term of the defect clusters in the tungsten metal at the peak position of the displacement damage; S4: Simplify the configuration space of the defect clusters; S5: Determine the reaction coefficients of different types of defect clusters; S6: Determine the concentration of the defect clusters during the irradiation time according to the source term, the configuration space, and the reaction coefficients; S7: Determine the simulation of the defects of tungsten metal according to the concentration.

[0023] The simulation method provided by the embodiments of the present application can improve the accuracy of determining the concentration of defect clusters within the irradiation time by determining the peak position of displacement damage, the source term, the reaction coefficients of different types of defect clusters, and simplifying the configuration space of the defect clusters, which is beneficial to improving the accuracy of simulating the defects of tungsten metal, and further beneficial to improving the accuracy of the research on the defects of tungsten metal; at the same time, by simplifying the configuration space of the defect clusters, the configuration space of the defect clusters can be effectively simplified, reducing the number of defect clusters to be determined, which is beneficial to improving the simulation efficiency of the defects of tungsten metal.

[0024] In some embodiments, the defects generated by irradiating tungsten metal with He ions and W ions can be defect clusters, such as vacancy-helium clusters V x He y , vacancy clusters V x , interstitial clusters I x , single defects, etc., where x and y are positive integers greater than or equal to 1, and the single defects can include He 1 , V 1 , I 1 .

[0025] In some embodiments, in step S1, the order of irradiating with He ions and W ions can be to irradiate with He ions first and then with W ions.

[0026] In some embodiments, in step S6, the source term, the configuration space, the reaction coefficients, and the concentration of the defect clusters within the irradiation time satisfy the following expression:

[0027]

[0028] Where C i is the concentration of the i-th type of defect cluster, t is the irradiation time, G i is the source term, L i is the total absorption rate of the i-th type of defect cluster by dislocations, grain boundaries, and surfaces, is the reaction coefficient for defect cluster j and defect cluster k to combine to form defect cluster i, is the reaction coefficient for defect cluster i and defect cluster j to combine to form defect cluster k, and N is the total number of this type of defect cluster in the configuration space.

[0029] In the related art, the sizes of the defects generated by irradiating tungsten metal with He ions and W ions are small and difficult to observe, for example, a few nanometers to dozens of nanometers. When the defect is less than 1 nanometer, it is difficult for a transmission electron microscope to observe the defect. However, in the embodiments of the present application, the concentration of any type of defect cluster within the irradiation time can be determined through the above expression, which is convenient for studying defects with small sizes, and further beneficial to improving the accuracy of simulating the defects of tungsten metal.

[0030] In some embodiments, the simulation of the defects of tungsten metal using the simulation method provided by the embodiments of the present application is an ion irradiation simulation carried out at room temperature, ignoring all decomposition reactions. In such embodiments, in the ion irradiation simulation carried out at room temperature, the decomposition reaction hardly occurs, so all decomposition reactions can be ignored, which is conducive to improving the accuracy of the total number of defect clusters in the configuration space.

[0031] See Figure 2 , in some embodiments, in step S2, it may further include: S21, determining the irradiation energies of He ions and W ions; S22, determining the displacement damage distribution of tungsten metal after irradiation by He ions and W ions according to the irradiation energies; S23, determining the displacement damage peak according to the displacement damage distribution; S24, determining the position of the displacement damage peak in step S23. In such embodiments, the position of the displacement damage peak of tungsten metal after irradiation can be determined through the above steps.

[0032] In some embodiments, since the displacement damage of tungsten metal after ion irradiation is very shallow (the displacement damage is close to the surface of tungsten metal and the depth is usually in the micron order of magnitude), it is difficult to observe the displacement damage. Therefore, in step S22, the SRIM software can be used to calculate and determine the displacement damage distribution of tungsten metal after irradiation by He ions and W ions according to the irradiation energies. In some embodiments, the damage depth distribution curve of tungsten metal after irradiation by He ions and W ions is obtained through calculation, and the displacement damage distribution of tungsten metal after irradiation by He ions and W ions is determined according to the damage depth distribution curve. Since the displacement damage at different depths is different, in order to facilitate the simulation of the defects of tungsten metal, the displacement damage peak, that is, the maximum point on the damage depth distribution curve, can be selected for the simulation of the defects of tungsten metal.

[0033] In some embodiments, in order to approach the spatial uniformity of the defects generated by high-energy neutron irradiation, the irradiation order and irradiation time of He ions and W ions can be designed so that the displacement damage peaks of tungsten metal after irradiation by He ions and W ions are almost the same.

[0034] See Figure 3, in some embodiments, in step S3, it may further include: S31. Determine the probability distribution of the displacement damage energy of tungsten metal after irradiation by He ions according to the irradiation energy in step S21; S32. Determine the displacement damage energy according to the probability distribution of the displacement damage energy in step S31; S33. Determine the displacement damage position of the displacement damage energy in step S32; S34. Determine the size distribution of cascade defect clusters at the displacement damage position in step S33; S35: Determine the irradiation fluence and irradiation time of He ions; S36: Determine the He ion concentration at the peak position of the displacement damage of tungsten metal after irradiation by He ions; S37. Determine the source term of the defect clusters at the peak position of the displacement damage of tungsten metal after irradiation by He ions according to the probability distribution of the displacement damage energy in step S31, the size distribution of cascade defect clusters in step S34, the irradiation fluence and irradiation time of He ions in step S35, and the He ion concentration in step S36. In such an embodiment, through the above steps, the source term of the defect clusters at the peak position of the displacement damage of tungsten metal after He ion irradiation can be determined according to the peak position of the displacement damage of tungsten metal after He ion irradiation.

[0035] In some embodiments, in step S31, the SRIM software may also be used to calculate and determine the probability distribution of the displacement damage energy of tungsten metal after irradiation by He ions according to the irradiation energy.

[0036] In some embodiments, in step S32, the displacement damage energy may be 10 typical damage energies randomly selected from the probability distribution of the displacement damage energy in step S31.

[0037] In some embodiments, in step S34, the size distribution of cascade defect clusters at the displacement damage position may be determined by performing room-temperature cascade collision simulations using molecular dynamics with the displacement damage positions of 10 typical damage energies.

[0038] In some embodiments, in step S36, the SRIM software may also be used to calculate and determine the depth distribution of He ions after irradiation of tungsten metal by He ions according to the irradiation energy; and determine the He ion concentration at the peak position of the displacement damage according to the He ion depth distribution and the peak position of the displacement damage.

[0039] In some embodiments, in step S37, the size distribution of cascade defect clusters in step S34 may be weighted by the probability distribution of the displacement damage energy in step S31, and then combined with the irradiation fluence and irradiation time of He ions in step S35 and the He ion concentration in step S36 to determine the source term of the defect clusters in tungsten metal at the peak position of the displacement damage of tungsten metal after irradiation by He ions.

[0040] In some embodiments, in step S37, the source term may include vacancy clusters V in tungsten metal after He ion irradiation x , interstitial clusters I x and the source term of He 1 .

[0041] See Figure 4 , in some embodiments, in step S3, it may further include: S31. Determine the probability distribution of the displacement damage energy of tungsten metal after W ion irradiation of tungsten metal according to the irradiation energy in step S21; S32. Determine the displacement damage energy according to the probability distribution of the displacement damage energy in step S31; S33. Determine the displacement damage position of the displacement damage energy in step S32; S34. Determine the size distribution of cascade defect clusters at the displacement damage position in step S33; S35: Determine the irradiation fluence and irradiation time of W ions; S36: Determine the source term of the defect clusters at the peak position of the displacement damage after W ion irradiation of tungsten metal according to the probability distribution of the displacement damage energy in step S31, the size distribution of cascade defect clusters in step S33, and the irradiation fluence and irradiation time of W ions in step S35. In such an embodiment, through the above steps, the source term of the defect clusters at the peak position of the displacement damage after W ion irradiation of tungsten metal can be determined according to the peak position of the displacement damage of tungsten metal after W ion irradiation.

[0042] In some embodiments, in step S31, the SRIM software may also be used to calculate and determine the probability distribution of the displacement damage energy of tungsten metal after W ion irradiation of tungsten metal according to the irradiation energy.

[0043] In some embodiments, in step S32, the displacement damage energy may be 10 typical damage energies randomly selected from the probability distribution of the displacement damage energy in step S31.

[0044] In some embodiments, in step S34, the size distribution of cascade defect clusters at the displacement damage position may be determined by performing room-temperature cascade collision simulations using molecular dynamics with the displacement damage positions of 10 typical damage energies.

[0045] In some embodiments, in step S36, the size distribution of cascade defect clusters in step S34 may be weighted by the probability distribution of the displacement damage energy in step S31, and then combined with the irradiation fluence and irradiation time of W ions in step S35 to determine the source term of the defect clusters in tungsten metal at the peak position of the displacement damage after W ion irradiation of tungsten metal.

[0046] In some embodiments, in step S36, the source term may include vacancy clusters V in tungsten metal after W ion irradiation x and interstitial clusters I x .

[0047] In some embodiments, the configuration space of the defect clusters can be a two-dimensional space. In some embodiments, an xoy coordinate system can be established within the configuration space of the defect clusters to characterize the position of the defect clusters in the configuration space through the two-dimensional coordinates (x, y) of the defect space.

[0048] See Figure 5 , in some embodiments, in step S4, it may further include: S41: Ignoring I x He y and I x He y V z clusters; S42: Determining the upper limit of the configuration space of the V x He y clusters; S43: Determining the lower limit of the configuration space of the V x He y clusters.

[0049] To simulate the defects of tungsten metal, it is necessary to determine the concentration of each defect cluster in the configuration space. For the V x He y clusters in the configuration space, the number of defect clusters to be determined is x*y. Assuming that the largest vacancy-helium cluster is V 272 He 816 , then the number of defect clusters to be determined is 221,952, resulting in a relatively low efficiency in simulating the defects of tungsten metal.

[0050] In such an embodiment, through the above steps, the configuration space of the defect clusters can be effectively simplified, and it also enables the simulation method provided by the embodiments of the present application to simulate higher He ion and W ion irradiation energies in a shorter time.

[0051] In some embodiments, the vacancy-helium cluster V x He y will undergo a capture mutation reaction within the configuration space. When the capture mutation reaction occurs, the vacancy-helium cluster V x He y will absorb the helium cluster He y and then extrude interstitial atoms, causing the volume of the vacancy-helium cluster V x He y to increase; afterwards, the vacancy-helium cluster V x He y will continuously undergo capture mutation reactions, causing the volume of the vacancy-helium cluster V x He y to continuously increase.

[0052] Specifically, the reaction process of the capture mutation reaction can be reflected by the following reaction formula:

[0053] He z +V x He y →V x He z+y →V x+1 He z+y +I 1 ,

[0054] Among them, x, y, and z are all positive integers greater than or equal to 1.

[0055] The continuous occurrence of the capture mutation reaction is due to the excessive gas pressure in the vacancy-helium cluster V x He y By extruding interstitial atoms, the volume of the vacancy-helium cluster V x He y can be increased, and the gas pressure in the vacancy-helium cluster V x He y can be reduced, so that the vacancy-helium cluster V x He y can continue to absorb helium clusters and continuously undergo capture mutation reactions.

[0056] In some embodiments, at room temperature, the vacancy clusters in metallic tungsten hardly diffuse, and the vacancy clusters in the vacancy-helium cluster V x He y are almost all obtained through capture mutation reactions. Therefore, when simplifying the configuration space of defect clusters, it is necessary to consider the capture mutation reaction of the vacancy-helium cluster V x He y .

[0057] In some embodiments, in step S41, molecular dynamics simulation can be used to simulate the capture mutation reaction, establish the relational expression of the x coordinate and y coordinate of the V x He y cluster, that is, the upper limit of the configuration space of the V x He y cluster. In the xoy coordinate system, clusters above the upper limit of the configuration space are unstable due to the occurrence of capture mutation reactions and can be regarded as non-existent.

[0058] In some embodiments, the diffusion of vacancy clusters can be ignored, and the relational expression of the x coordinate and y coordinate of the V x He y cluster can be established according to the capture mutation reaction, that is, the lower limit of the configuration space of the V x He y cluster. In the xoy coordinate system, clusters below the lower limit of the configuration space cannot be formed through capture mutation reactions.

[0059] In some embodiments, in step S4, it may further include determining the total number of each type of defect cluster in the simplified configuration space.

[0060] In some embodiments, in step S5, it may further include: S51: determining that the type of the defect cluster is one of a helium cluster and an interstitial cluster; S52: determining the capture radius and diffusion coefficient of the defect cluster in step S51; S53: determining the capture radius and diffusion coefficient of the reactant that reacts with the defect cluster in step S51. In such an embodiment, the type of the defect cluster can be determined through the above steps, which is conducive to determining the reaction coefficients of different types of defect clusters.

[0061] At room temperature, different types of defect clusters in tungsten metal have different diffusion modes. For example, the interstitial cluster I in tungsten metal x will undergo one-dimensional diffusion along the close-packed lattice direction

[111] , and the helium cluster He in tungsten metal y will undergo three-dimensional diffusion. Since the mean free paths of three-dimensional diffusion and one-dimensional diffusion are different, the determination methods of the reaction coefficients of different types of defect clusters are different. Therefore, when determining the reaction coefficient of the defect cluster, it is necessary to first determine the type of the defect cluster.

[0062] In some embodiments, in step S53, the reactants that react with the helium cluster or the interstitial cluster can be a helium cluster, a vacancy cluster, and a vacancy-helium cluster.

[0063] In one embodiment, when the type of the defect cluster in step S51 is a helium cluster, in step S5, it may further include: S54: determining the reaction coefficient of the defect cluster according to the capture radius and diffusion coefficient of the defect cluster in step S52 and the capture radius and diffusion coefficient of the reactant in step S53. In such an embodiment, the reaction coefficient of the helium cluster can be determined through the above steps.

[0064] In some embodiments, the determined reaction coefficients in step S54 may include: the reaction coefficient between helium clusters, the reaction coefficient between a helium cluster and a vacancy cluster, and the reaction coefficient between a helium cluster and a vacancy-helium cluster.

[0065] In some embodiments, the reaction coefficient K between a helium cluster and a reactant may satisfy the following expression:

[0066] K = 4π(R 1 + R 2 )(D 1 + D 2 ),

[0067] wherein, R 1 is the capture radius of the helium cluster, R 2 is the capture radius of the reactant, and D 1is the diffusion coefficient of helium clusters, D 2 is the diffusion coefficient of the reactants.

[0068] In some embodiments, when the type of the defect clusters in step S51 is interstitial clusters, in step S5, it may further include: S54: determining the type of the reactants in step S53; S55: determining the reaction coefficient of the defect clusters according to the capture radius and diffusion coefficient of the defect clusters in step S52, the capture radius and diffusion coefficient of the reactants in step S53, and the type of the reactants in step S53. In such embodiments, the reaction coefficient of the interstitial clusters can be determined through the above steps.

[0069] In some embodiments, the determined reaction coefficients in step S54 may include: the reaction coefficient between interstitial clusters and interstitial clusters, the reaction coefficient between interstitial clusters and vacancy clusters, and the reaction coefficient between interstitial clusters and vacancy-helium clusters.

[0070] In some embodiments, the reaction coefficient K between interstitial clusters and interstitial clusters may satisfy the following expression:

[0071]

[0072] wherein, R 1 and R 2 are the capture radii of the interstitial clusters, D 1 and D 2 are the diffusion coefficients of the interstitial clusters, C 1 and C 2 are the concentrations of the interstitial clusters.

[0073] When determining the reaction coefficient K between interstitial clusters and interstitial clusters using the above expression, it is necessary to satisfy D1≥D2. If not, the rightmost term of the above expression is

[0074] In some embodiments, the reaction coefficients between interstitial clusters and vacancy clusters and between interstitial clusters and vacancy-helium clusters K may satisfy the following expression:

[0075] K = 6π 2 D(R 1 +R 2 ) 2 ∑ s C s (R 1 +R s ) 2 ,

[0076] wherein, D represents the diffusion coefficient of the interstitial clusters, C sis the concentration of all defect clusters that react with interstitial clusters, including the concentration of vacancy clusters, the concentration of vacancy - helium clusters, and the concentration of interstitial clusters, R s is the capture radius of the defect clusters that react with interstitial clusters, R 1 is the capture radius of interstitial clusters, R 2 is the capture radius of the reactants that react with interstitial clusters; among them, the reaction coefficient between interstitial clusters and reactants not only depends on the characteristics of interstitial clusters and reactants, but also is related to the characteristics of other reactants that can react with interstitial clusters. To ensure the accuracy of the reaction coefficient K, it is necessary to traverse all defect clusters that can react with interstitial clusters.

[0077] In some embodiments, in step S5, it may further include: ignoring the absorption of He clusters by dislocations, grain boundaries, and surfaces; determining the reaction coefficients of the reaction between interstitial clusters and dislocations, grain boundaries, and surfaces.

[0078] In some embodiments, the reaction coefficient of the reaction between interstitial clusters and dislocations may satisfy the following expression:

[0079]

[0080] In the formula, D represents the diffusion coefficient of interstitial clusters, ρ represents the dislocation density, r d represents the dislocation core radius.

[0081] In some embodiments, the reaction coefficient of the reaction between interstitial clusters and grain boundaries may satisfy the following expression:

[0082]

[0083] In the formula, D represents the diffusion coefficient of interstitial clusters, R gb represents the grain radius.

[0084] In some embodiments, the reaction coefficient of the reaction between interstitial clusters and surfaces may satisfy the following expression:

[0085]

[0086] In the formula, D represents the diffusion coefficient of interstitial clusters, l represents the thickness of tungsten metal.

[0087] In some embodiments, the reaction coefficient between interstitial clusters and interstitial clusters, the reaction coefficient between interstitial clusters and vacancy clusters, and the reaction coefficient between interstitial clusters and vacancy - helium clusters may change with the irradiation time. Substituting the above reaction coefficients into the relationships of the source term, configuration space, reaction coefficient, and the concentration of defect clusters during the irradiation time, a series of ordinary differential equations with different coefficients can be obtained, and these equations can form a system of ordinary differential equations with variable coefficients.

[0088] In some embodiments, the total absorption rate L of dislocations, grain boundaries, and surfaces for the i-th type of defect cluster i can be determined according to the reaction coefficient related to defect cluster i and the diffusion coefficient of defect cluster i.

[0089] In some embodiments, the ion irradiation time, the concentration, source term, total number in the configuration space, and reaction coefficient corresponding to each type of defect cluster can be substituted into the above relationships of the source term, configuration space, reaction coefficient, and the concentration of defect clusters during the irradiation time to obtain a differential equation related to the concentration of each type of defect cluster during the irradiation time, and further obtain a system of differential equations related to the concentration of each type of defect cluster during the irradiation time. By solving the above system of differential equations, the simulation of the defects in tungsten metal is realized.

[0090] In some embodiments, the initial state value of the system of differential equations can be set to 0, and by solving the system of differential equations, the final state value of the system can be obtained to realize the simulation of the defects in tungsten metal during the He ion irradiation stage; the final state value of the system of equations obtained above is set as the initial state value of the system of equations for the next solution, and by solving the system of differential equations again, the final state value of the system of differential equations under this initial state value can be obtained to realize the simulation of the defects in tungsten metal during the W ion irradiation stage; by combining the above two simulation processes, the entire simulation of the defects in tungsten metal is completed, where the system of differential equations can be solved by calling the open-source differential equation solver LSODA or SUNDIALS.

[0091] The process of simulating the defects in tungsten metal will be described in detail below.

[0092] Simulate the irradiation of tungsten metal with He ions at an irradiation energy of 200 keV and W ions at an irradiation energy of 4 MeV. Calculate the displacement damage distribution, displacement damage energy probability distribution after the irradiation of He ions and W ions, and the He ion concentration at the displacement damage peak position of tungsten metal after the irradiation of He ions through the SRIM software, and then determine the source term after the irradiation of He ions and the source term after the irradiation of W ions. Taking the irradiation of He ions as an example, under the irradiation of 200 keV He ions, the displacement damage peak is around 10 keV. Molecular dynamics simulation is used to simulate the cascade collisions at energies from 1 to 10 keV to obtain the size distribution of cascade defect clusters, and then weighted by the damage energy probability distribution to obtain the source term after the irradiation of He ions.

[0093] After that, simplify the configuration space of the defect cluster, refer to Figure 6 , with y = 5x 0.86 as the upper limit 51 of the configuration space, and y = 5(x - 1) 0.86 +1 as the lower limit 52 of the configuration space, and simplify the configuration space 53 to obtain the simplified configuration space 53.

[0094] After that, the reaction coefficients of each type of defect cluster are calculated according to the expressions satisfied by the reaction coefficients of different types of defect clusters.

[0095] After that, the concentration of each type of defect cluster is determined. Taking the V n He m cluster as an example, due to the lower limit of the configuration space, it cannot absorb interstitial clusters. Otherwise, a capture mutation reaction will occur immediately after absorption and interstitial atoms will be released. And since vacancy clusters do not diffuse at room temperature, only the reaction between the V n He m cluster and the helium cluster needs to be considered. Taking the above into account, the differential equation related to the concentration of the V n He m cluster during the irradiation time is as follows:

[0096]

[0097] After that, the open-source differential equation solver LSODA or SUNDIALS is used to simulate the He and W ion irradiation stages respectively, and the simulation of the defects in tungsten metal is obtained.

[0098] For the embodiments of the present application, it should also be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other to obtain new embodiments.

[0099] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. The protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for simulating defects in metal tungsten, wherein the defects are caused by irradiation of the metal tungsten with He ions and W ions, characterized in that: It includes the following steps: S1: simulating the He ions and the W ions irradiating the metal tungsten; S2: determining the off-site damage peak position of the metal tungsten after the metal tungsten is irradiated in step S1; S3: determining the source term of the defect cluster in the metal tungsten at the off-situ damage peak position; S4: simplifying the configuration space of the defect clusters; S5: determining the reaction coefficients of different types of defect clusters; S6: determining the concentration of the defect clusters within the irradiation time according to the source term, the configuration space and the reaction coefficient; S7: Determine a simulation of defects of the metal tungsten according to the concentration; In step S6, the source term, the configuration space, the reaction coefficient, and the concentration of the defect clusters during the irradiation time satisfy the following expressions: ， i =1~ N in For the i The concentration of the defect clusters is t is the irradiation time, is the source term, is the total absorption rate of dislocation, grain boundary and surface to the i-th defect cluster, is the reaction coefficient of defect cluster j combining with defect cluster k to form defect cluster i, is the reaction coefficient of defect cluster i combining with defect cluster j to form defect cluster k, N is the total number of defect clusters in the configuration space; The configuration space of the defect cluster is a two-dimensional space; In step S4, it also includes: S41: Ignore I x He y and I x He y V z Clusters; S42: Determine V x He y The upper limit of the cluster's configuration space; S43: Determine V x He y The lower limit of the configuration space of the cluster.

2. The method according to claim 1, characterized in that The simulations are ion irradiation simulations performed at room temperature, ignoring all decomposition reactions.

3. The method according to claim 1, characterized in that In step S2, it also includes: S21, determining the irradiation energy of the He ions and the W ions; S22, determining, according to the irradiation energy, the off-situ damage distribution of the metal tungsten after the metal tungsten is irradiated by the He ions and the W ions; S23, determining an off-site damage peak value according to the off-site damage distribution; S24, determining the off-site damage peak position in step S23.

4. The method according to claim 3, characterized in that In the S3 step, it also includes: S31, determining the probability distribution of off-situ damage energy of the metal tungsten after the metal tungsten is irradiated by the He ions according to the irradiation energy of step S21; S32, determining the off-site damage energy according to the off-site damage energy probability distribution in step S31; S33, determining the off-site damage position of the off-site damage energy in step S32; S34, determining the size distribution of the cascade defect clusters at the off-site damage position of step S33; S35: Determine the irradiation dose and irradiation time of the He ions; S36: determining the He ion concentration at the peak position of the off-situ damage to the metal tungsten after the metal tungsten is irradiated by the He ions; S37: According to the off-situ damage energy probability distribution of step S31, the cascade defect cluster size distribution of step S34, the He ion irradiation dose and irradiation time of step S35 and the He ion concentration of step S36, determine the source term of the defect cluster at the off-situ damage peak position after the He ions irradiate the metal tungsten.

5. The method according to claim 3, characterized in that: In the S3 step, it also includes: S31, determining the probability distribution of off-situ damage energy of the metal tungsten after the metal tungsten is irradiated by the W ions according to the irradiation energy of step S21; S32, determining the off-site damage energy according to the off-site damage energy probability distribution in step S31; S33, determining the off-site damage position of the off-site damage energy in step S32; S34, determining the size distribution of the cascade defect clusters at the off-site damage position of step S33; S35: Determine the irradiation dose and irradiation time of the W ions; S36: According to the off-situ damage energy probability distribution of step S31, the cascade defect cluster size distribution of step S33, and the irradiation dose and irradiation time of the W ions in step S35, determine the source term of the defect cluster at the off-situ damage peak position after the W ions irradiate the metal tungsten.

6. The method according to claim 1, characterized in that In step S5, it also includes: S51: Determine that the type of the defect cluster is one of a helium cluster and an interstitial cluster; S52: Determine the capture radius and diffusion coefficient of the defect cluster in step S51; S53: Determine the capture radius and diffusion coefficient of the reactants that react with the defect clusters in step S51.

7. The method according to claim 6, characterized in that When the type of the defect cluster in step S51 is a helium cluster, step S5 further includes: S54: Determine the reaction coefficient of the defect cluster according to the capture radius and diffusion coefficient of the defect cluster in step S52 and the capture radius and diffusion coefficient of the reactant in step S53.

8. The method according to claim 6, characterized in that When the type of the defect cluster in step S51 is a gap cluster, step S5 further includes: S54: Determine the type of the reactant in step S53; S55: Determine the reaction coefficient of the defect cluster according to the capture radius and diffusion coefficient of the defect cluster in step S52, the capture radius and diffusion coefficient of the reactant in step S53, and the type of the reactant in step S53.

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