CN114970106B - Method and system for predicting radiation hardening based on microstructure - Google Patents
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Abstract
The invention discloses a method and a system for predicting radiation hardening based on a microstructure, which comprises the following steps: obtaining the chemical free energy density of the nuclear power alloy material according to the Avogardlo constant, the atom molar volume, the defect atom concentration, the defect forming energy, the Boltzmann constant and the absolute temperature of the nuclear power alloy material; acquiring the elastic free energy density of the nuclear power alloy material based on the crystal plasticity of the nuclear power alloy material; constructing a thermodynamic system model for representing the evolution of the irradiation defects of the nuclear power alloy material according to the chemical free energy density and the elastic free energy density; based on a thermodynamic system model, constructing a phase field kinetic model by acquiring the chemical mobility of irradiation point defects, the generation rate of the point defects under irradiation conditions and the concentration of defect atoms of a nuclear power alloy material; the invention introduces microscopic defects in the process of considering irradiation and considers the hardening of the defects in the stretching process, thereby improving the prediction precision of irradiation hardening and the engineering application value of calculation simulation.
Description
Technical Field
The invention relates to the technical field of performance prediction of nuclear power materials under irradiation conditions, in particular to a method and a system for predicting irradiation hardening based on a microstructure.
Background
In 2020-2050 years, the fast breeder reactor is planned to be developed in China, and one of the key points of project development is the nuclear material problem. Due to the generation of a large number of point defects and the interaction between the point defects and atoms in the service process, main elements of the material are segregated at crystal boundaries and dislocation positions, so that irradiation defects such as irradiation induced precipitation, dislocation loops, cavities and the like are generated. These defects may hinder dislocation motion, causing radiation hardening, while at the same time reducing the ductility of the material leading to deterioration of the material. Therefore, understanding the relationship between irradiation defects and material property changes is critical to long-life service and life prediction of nuclear power materials.
Because of the radioactivity of neutron irradiation and the difficulty of neutron experiments, heavy ion irradiation is mostly adopted to simulate the neutron irradiation effect for the irradiation effect research of nuclear power materials at present. But the damage degree of the irradiation layer irradiated by ions is small (< 1 μm) and the size of the sample is small, so that the mechanical property experiment of the heavy ion irradiation material is challenged. At present, nano indentation is mostly applied, but the technology can only be used for detecting the change of hardness before and after irradiation and extrapolating the change of yield strength of the material, the calculated value is often different from the calculated value of a microstructure, and the stress-strain response relation of the irradiated material is difficult to establish. Another test technique is a microcolumn tensile/compression experiment, which can better reflect the radiation hardening effect, but the equipment is difficult to obtain and high in cost. And then, the researchers adopt various simulation means to predict the radiation stress-strain response and study the defect interaction. The irradiation hardening is closely related to the irradiated microstructure, the phase field simulation is used as a microscopic scale simulation means, due to the unique advantages of the phase field simulation at the microstructure level, the method obtains wide attention of domestic and foreign scholars, the phase field method can carry out the collaborative research on defect generation and performance change, improves the prediction precision of the irradiation hardening of the material and can obtain the stress strain response relation, and the method is a new direction for the prediction of the irradiation performance and service life evolution of the nuclear power material.
Disclosure of Invention
In order to solve the problems, the invention aims to provide a method and a system for predicting radiation hardening based on a microstructure, which comprehensively consider irradiation microscopic defects based on phase field simulation and a crystal plasticity theory and improve the prediction precision and the engineering applicability of radiation hardening.
In order to achieve the above technical object, the present application provides a microstructure-based irradiation hardening prediction method, comprising the steps of:
acquiring the chemical free energy density of the nuclear power alloy material according to the Avogastron constant, the atom molar volume, the defect atom concentration, the defect forming energy, the Boltzmann constant and the absolute temperature of the nuclear power alloy material;
acquiring the elastic free energy density of the nuclear power alloy material based on the crystal plasticity of the nuclear power alloy material;
constructing a thermodynamic system model for representing the evolution of the irradiation defects of the nuclear power alloy material according to the chemical free energy density and the elastic free energy density;
based on a thermodynamic system model, a phase field dynamics model is constructed by obtaining the chemical mobility of irradiation point defects, the generation rate of the point defects under irradiation conditions and the defect atom concentration of the nuclear power alloy material, wherein the phase field dynamics model is used for performing irradiation hardening prediction on the nuclear power alloy material.
Preferably, in the process of obtaining the elastic free energy density, the elastic free energy density is obtained by collecting an elastic constant and an elastic strain tensor of the nuclear power alloy material.
Preferably, in the process of collecting the elastic strain tensor, the external strain, the non-uniform strain and the intrinsic strain of the nuclear power alloy material are collected to generate the elastic strain tensor.
Preferably, in the process of acquiring the intrinsic strain, the intrinsic strain is acquired according to a coupled crystal plasticity theory by acquiring a volume expansion coefficient related to the defect, a defect equilibrium concentration at a certain temperature, a plastic strain tensor and a defect atom concentration.
Preferably, in the process of obtaining the plastic strain tensor, the plastic strain tensor is generated by obtaining the number of slip systems, the plastic shear rate of the slip systems, the initial plastic shear rate, the strain sensitivity index, the Schimid tensor factor, the shear stress and the critical shear stress, wherein when the system shear stress is greater than the critical shear stress, slip occurs, and the Schimid tensor factor is obtained by obtaining the slip direction and the normal direction of the slip systems.
Preferably, in the process of obtaining the critical shear stress, based on the irradiation hardening and the strain hardening, a hardening equation is constructed by obtaining the critical shear stress of the nuclear power alloy material when not irradiated, the increasing function of the critical shear stress caused after being irradiated, and the strength factor related to the defect type, the shear modulus of the material, the berms vector, the hardening constant, the initial hardening coefficient, the hardening index, the saturated critical shear stress, the density of the defect, and the size of the defect, and the critical shear stress is obtained according to the difference method.
Preferably, in the process of constructing the hardening equation, the initial hardening coefficient and the saturated critical shear stress are obtained in consideration of the first hardening parameter of the austenite matrix, the second hardening parameter of the dislocation loops, and the defect atom concentration, based on the phase field variables.
Preferably, in the process of constructing the phase field dynamic model, a relational expression model of the stress strain field and the plastic strain is constructed; the method comprises the steps of obtaining a strain field in a fast Fourier transform mode, obtaining a stress field according to a generalized Hooke law, and obtaining plastic strain according to a crystal plasticity theory.
Preferably, in the process of predicting the radiation hardening of the nuclear power alloy material, the free energy variational is obtained according to the variational of the chemical free energy to the components and the variational of the elastic energy to the components;
based on a phase field dynamics model, according to a semi-implicit Fourier spectrum method, chemical free energy density, plastic strain and elastic free energy density for next iteration are respectively obtained by obtaining a free energy variation component and a relation expression model until the iteration reaches a set external tensile strain value, and irradiation hardening prediction is carried out on the nuclear power alloy material after data are processed quantitatively.
The invention also discloses a system for predicting radiation hardening based on the microstructure, which comprises:
the chemical free energy density generating module is used for acquiring the chemical free energy density of the nuclear power alloy material according to the Avogardo constant, the atom molar volume, the defect atom concentration, the defect forming energy, the Boltzmann constant and the absolute temperature of the nuclear power alloy material;
the elastic free energy density generation module is used for acquiring the elastic free energy density of the nuclear power alloy material based on the crystal plasticity of the nuclear power alloy material;
the thermodynamic system module is used for constructing a thermodynamic system model for representing the evolution of the irradiation defects of the nuclear power alloy material according to the chemical free energy density and the elastic free energy density;
the radiation hardening prediction module is used for constructing a phase field dynamics model by acquiring the chemical mobility of irradiation point defects, the generation rate of the point defects under irradiation conditions and the defect atom concentration of the nuclear power alloy material based on a thermodynamic system model, wherein the phase field dynamics model is used for performing radiation hardening prediction on the nuclear power alloy material.
The invention discloses the following technical effects:
the invention can research the relation between radiation hardening and defects by utilizing phase field simulation, and obtain a stress-strain curve, thereby being capable of making up the deficiency of experimental research in a limited way;
according to the invention, microscopic defects are introduced in the process of considering irradiation, and the hardening of the defects in the stretching process is considered, so that the prediction precision of irradiation hardening and the engineering application value of calculation simulation are improved;
the prediction method provided by the invention is simple, and the required parameters are obtained by adopting conventional TEM representation and tensile experiment.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
Fig. 1 is a schematic diagram of a phase field simulation flow for predicting radiation hardening according to the present invention.
FIG. 2 shows dislocation loop distribution experiments and simulation comparisons of 316 austenitic stainless steel of the present invention irradiated at room temperature for 1 dpa.
Fig. 3 is an experimental and simulated comparison of the stress-strain curves of 316 austenitic stainless steels at room temperature and 550 c in accordance with the present invention.
Fig. 4 is a prediction of the radiation hardening stress-strain curve of 316 austenitic stainless steel according to the present invention.
Fig. 5 is a comparison of phase field predicted radiation hardening and experiment for 316 austenitic stainless steel according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, 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, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present application without making any creative effort, shall fall within the protection scope of the present application.
As shown in fig. 1 to 5, the present invention provides a method for predicting radiation hardening based on a microstructure, comprising the steps of:
obtaining the chemical free energy density of the nuclear power alloy material according to the Avogardlo constant, the atom molar volume, the defect atom concentration, the defect forming energy, the Boltzmann constant and the absolute temperature of the nuclear power alloy material;
acquiring the elastic free energy density of the nuclear power alloy material based on the crystal plasticity of the nuclear power alloy material;
constructing a thermodynamic system model for representing the evolution of the irradiation defects of the nuclear power alloy material according to the chemical free energy density and the elastic free energy density;
based on a thermodynamic system model, a phase field dynamics model is constructed by obtaining the chemical mobility of irradiation point defects, the generation rate of the point defects under irradiation conditions and the defect atom concentration of the nuclear power alloy material, wherein the phase field dynamics model is used for performing irradiation hardening prediction on the nuclear power alloy material.
Further preferably, in the process of obtaining the elastic free energy density, the elastic free energy density is obtained by collecting the elastic constant and the elastic strain tensor of the nuclear power alloy material.
Further preferably, in the process of collecting the elastic strain tensor, the elastic strain tensor is generated by collecting the external strain, the non-uniform strain and the intrinsic strain of the nuclear power alloy material.
Further preferably, in the process of acquiring intrinsic strain, the intrinsic strain is acquired according to the coupled crystal plasticity theory by acquiring the volume expansion coefficient related to the defect, the defect equilibrium concentration at a certain temperature, the plastic strain tensor and the defect atom concentration.
Further preferably, in the process of obtaining the plastic strain tensor, the plastic strain tensor is generated by obtaining the number of the slip systems, the plastic shear rate of the slip systems, the initial plastic shear rate, the strain sensitivity index, the Schimid tensor factor, the shear stress and the critical shear stress, wherein when the shear stress of the system is greater than the critical shear stress, the slip occurs, and the Schimid tensor factor is obtained by obtaining the slip direction and the normal direction of the slip systems.
Further preferably, in the process of obtaining the critical shear stress, based on the irradiation hardening and the strain hardening, the invention constructs a hardening equation by obtaining the critical shear stress of the nuclear power alloy material when not irradiated, the increasing function of the critical shear stress caused after being irradiated, and the strength factor related to the defect type, the shear modulus of the material, the bobber vector, the hardening constant, the initial hardening coefficient, the hardening index, the saturated critical shear stress, the density of the defect, and the size of the defect, and obtains the critical shear stress according to the difference method.
Further preferably, in the process of constructing the hardening equation, the initial hardening coefficient and the saturation critical shear stress are obtained in consideration of the present invention according to the first hardening parameter of the austenite matrix, the second hardening parameter of the dislocation loops, and the defect atom concentration, based on the phase field variables.
Further preferably, in the process of constructing the phase field dynamics model, the invention also constructs a relational expression model based on the stress strain field and the plastic strain; the method comprises the steps of obtaining a strain field in a fast Fourier transform mode, obtaining a stress field according to a generalized Hooke law, and obtaining plastic strain according to a crystal creep theory.
Preferably, in the process of predicting the radiation hardening of the nuclear power alloy material, the free energy variation is obtained according to the variation of chemical free energy to components and the variation of elastic energy to components;
based on a phase field dynamics model, according to a semi-implicit Fourier spectrum method, chemical free energy density plastic strain and elastic free energy density for next iteration are respectively obtained by obtaining a free energy variation component and a relation expression model until the iteration reaches a set external tensile strain value, and after data is processed quantitatively, radiation hardening prediction is carried out on the nuclear power alloy material.
The invention also discloses a system for predicting radiation hardening based on the microstructure, which comprises:
the chemical free energy density generating module is used for acquiring the chemical free energy density of the nuclear power alloy material according to the Avogardo constant, the atom molar volume, the defect atom concentration, the defect forming energy, the Boltzmann constant and the absolute temperature of the nuclear power alloy material;
the elastic free energy density generation module is used for acquiring the elastic free energy density of the nuclear power alloy material based on the crystal plasticity of the nuclear power alloy material;
the thermodynamic system module is used for constructing a thermodynamic system model for representing the evolution of the irradiation defects of the nuclear power alloy material according to the chemical free energy density and the elastic free energy density;
the radiation hardening prediction module is used for constructing a phase field dynamics model by acquiring the chemical mobility of irradiation point defects, the generation rate of the point defects under irradiation conditions and the defect atom concentration of the nuclear power alloy material based on a thermodynamic system model, wherein the phase field dynamics model is used for performing radiation hardening prediction on the nuclear power alloy material.
Example 1: in the embodiment, the method for predicting radiation hardening based on a microstructure provided by the invention is adopted, and 316 austenitic stainless steel is taken as an example, and the method comprises the following steps:
fig. 1 is a schematic flowchart of a prediction method based on radiation hardening of a microstructure provided in an embodiment of the present specification.
Step 102: establishing 316 austenitic stainless steel irradiation thermodynamic system model to obtain thermodynamic parameters
System thermodynamics is embodied as a function of field variables:
wherein F is the total free energy of the system (unit is J) and is derived from the chemical free energy F ch (unit is J) and elastic free energy F el (unit is J) composition. f. of ch Is the chemical free energy density (unit is J/m) 3 )，f el Is the elastic free energy density (unit is J/m) 3 ) dV is the unit volume of the system (in m) 3 )。
The expression of the chemical free energy density is:
wherein N is an Avogadro constant (unit is mol-1), and Ω is an atomic molar volume (unit is m) 3 /mol)，c i Defect atom concentration (in at.%), E i Is the energy of formation of defects (in J), k B Boltzmann constant (in J/K) and T absolute temperature (in K).
Determining E from first-principles calculations or literature references i ，E i The values are determined such that the simulated defect microstructure is similar to the experiment, and the remaining constants are constant values.
Step 104: considering crystal plasticity, establishing an expression of the elastic free energy of 316 austenitic stainless steel, obtaining parameters,
the expression for establishing the elastic free energy density based on crystal plasticity is as follows:
wherein, C ijkl Is a constant of elasticity of the magnetic particles,
is made elasticA strain tensor.
wherein epsilon 0 For the volumetric expansion coefficient associated with the defect,
the equilibrium concentration of defects at a certain temperature (in at.%), delta ij Is the constant of the Kronecker,
the plastic strain tensor is calculated by a coupled crystal plasticity theory in phase field simulation.
Value epsilon 0 ＝0.001；
By
Calculated at room temperature
C ijkl Calculated by first principles or obtained by literature.
Step 106: establishing a crystal plastic model and obtaining parameters
The expression of the plastic strain tensor is:
wherein N is the total number of slip systems of the system,
the plastic shear rate (unit is s-1) of the slip system alpha,
is the initial plastic shear rate (in s-1), n is the strain sensitivity index,
is a Schimid tensor factor, I α Is the slip direction, n α Normal to the slip system,. Tau α ＝σ:m α For shear stress, σ is the stress tensor,
is the critical shear stress. When the system shear stress is greater than the critical shear stress, slip occurs.
The value of n is 20 according to the plastic finite element of the crystal; m is α Depends on the slip system of different materials, which is {111} for 316 austenitic stainless steel<110>A slipping system;
is a starting value of 0 Is calculated to obtain 0 ＝Sσ y Where σ is y S is a Schmid factor and is 0.41, which is the yield strength of the material and is obtained through experiments.
Step 108: determining radiation hardening and strain hardening, and obtaining a hardening value of critical shear stress:
considering the specific expressions of radiation hardening and strain hardening as,
wherein,
is the critical shear stress of the unirradiated material,
for the increase of critical shear stress caused by irradiation, α is the intensity factor related to the defect type, μ is the shear modulus of the material, b is the Boehringer vector, q is αβ In order to be a hardening constant, the composition,
is the initial hardening coefficient (in MPa), m is the hardening index,. Tau. s Is the saturated critical shear stress (MPa), N is the density of the defect, d is the size of the defect, dt is the simulated time step,
the plastic shear rate of the beta slip system.
For the hardening parameters of the dislocation loops to be distinguished from those of the austenitic matrix, based on the combination of the component field of the phase field simulation and the crystallographic plasticity, the hardening parameters of the overall system are expressed as follows,
wherein,
is a hardening parameter of the austenitic matrix,
is the hardening parameter of the dislocation loops.
And
is believed to be proportional to the austenite group parameter,
where k is a constant.
N and d were determined by TEM of the irradiated sample to be 4.27X 1022m-3 and 5.7nm, respectively. The irradiation defect of the embodiment is a dislocation loop, alpha is a strengthening factor of the dislocation loop, and can be obtained from related documents, 0.4 is taken, and tau is calculated ir Is 121.9MPa.
Taking into account the hardening process of the same slip system, q αβ The value is 1;
and τ s For the fitting value, take and 0 in a proportional manner, the amount of the solvent,
τ s /τ 0 and fitting according to stress-strain curves of experiments at room temperature and 550 ℃. And m is a combination of literature values and fitting.
The hardening parameters for dislocation loops should be distinguished from those of the austenitic matrix. According to the formula, the method comprises the following steps of,
wherein alpha is L Respectively representing irradiated dislocation loops and alpha ρ Strengthening factor of forest dislocation, alpha L Usually 0.3-0.45, alpha ρ Usually 0.2 is taken. In the present embodiment, the dislocation loop takes k to 2 in the crystal plastic model.
The hardening equation is solved by using a difference method,
the solved critical shear stress is the necessary parameter for solving the plastic strain of step 106.
Step 110: solving stress equations
The stress strain field and the plastic strain are obtained by solving the following relationship,
wherein,
consider the plastic strain at the beginning of the simulation to be 0.
The stress strain field is solved by adopting a fast Fourier transform mode,
wherein omega ik (n) is a Green function, n j ，n l Unit vector of Fourier space, c i (g) Is a fourier transform of the components. Initial value of plastic strain
ε kl And (r) solving a strain field by inverse Fourier transform, and solving a stress field by generalized Hooke's law.
The plastic strain can then be found from the crystal plasticity equation of step 106.
Step 112: establishing defect evolution phase field equation and solving
The phase field dynamics model is as follows:
wherein M is i Chemical mobility of irradiation point defects, g i Is the rate of generation of point defects under irradiation conditions. The variation of the free energy to the composition is related to the chemical free energy and the elastic energy, respectively, deltaF/deltac i ＝δ(F ch +F el )/δc i . The variation of the chemical free energy versus composition can be determined from the formula in step 102,
the strain field and the plastic strain field solved for by the stress-strain-field solution method of step 110, the variation of the elastic energy versus the composition according to step 104 can be expressed as,
M i ＝c i D i /k B [ in which D is i Is the diffusion coefficient of the point defect;
and substituting the obtained free energy variation into a phase field kinetic equation, and solving the phase field kinetic equation by adopting a semi-implicit Fourier spectrum method. And (6) substituting the obtained component field into the chemical free energy in the step 102 and solving the stress strain field in the step 110, and obtaining the plastic strain and the free energy variation component of the next iteration step until the iteration is carried out to the set external tensile strain value. The data are processed quantitatively through MATLAB and other software, the irradiation hardening can be predicted, the table 1 provides main physical parameters of specific embodiments, in the technical scheme, the service temperature applicable to the irradiation hardening prediction method is 25-600 ℃, and the strain range applicable to the irradiation hardening prediction method is 0-0.05.
TABLE 1
FIG. 2 is an experiment and simulation comparison of a microstructure of 316 austenitic stainless steel irradiated at room temperature by 1dpa by using the microstructure-based irradiation hardening prediction method provided by the invention, wherein irradiation defects are mainly dislocation loops, and the method has better consistency compared with an actual experiment, and better simulates the characteristic of uneven distribution of heavy ion irradiation defects, thereby indicating that the method provided by the invention can be used for predicting the material irradiation microstructure.
Fig. 3 is an experimental and simulated comparison of stress-strain response of non-irradiated 316 austenitic stainless steel using a microstructure-based irradiation hardening prediction method proposed by the present invention. It can be found that the room temperature and high temperature stress strain response based on the simulation of the present invention has good correspondence with the experiment and the literature. The method provided by the invention can be used for obtaining the stress-strain response of the material.
Fig. 4 is a stress-strain curve after irradiation hardening obtained by irradiating 316 austenitic stainless steel of 1dpa at room temperature using a microstructure-based irradiation hardening prediction method according to the present invention. The yield strength after irradiation from this stress-strain curve was 813MPa. Obtaining defect density and size from TEM tissue map by discrete enhanced model (DBH model)
The yield strength value calculated by (M is 3.06) is 673MPa, and the actual yield strength obtained by nano indentation test is 865MPa, so that the stress-strain response of the material after ion irradiation can be obtained, and the prediction precision of irradiation hardening can be improved.
Fig. 5 is a comparison between the prediction of yield strength change after 316 austenitic stainless steel irradiation and experimental values by using the microstructure-based irradiation hardening prediction method provided by the invention, and a comparison between the prediction accuracy and the yield strength change predicted by a traditional discrete strengthening model (DBH model). According to the irradiation microscopic defects of the experiments, irradiation dislocation loops are the main irradiation microscopic defects, and it can be found that the phase field model can well predict irradiation hardening and has higher prediction precision. Meanwhile, compared with the uncertainty of the alpha value of the traditional discrete enhanced model (DBH model), the alpha value in the phase field model is 0.4, and the uniformity and the certainty of a prediction result are improved.
The embodiment result shows that the method for predicting the radiation hardening effect of the material and obtaining the stress-strain response relation provides a new prediction method for the radiation hardening of the material. The method can be used as a theoretical reference for nuclear power structural material design and service life prediction under irradiation conditions, and the engineering applicability of the phase field theory is improved.
The present invention has been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (8)
1. A microstructure-based irradiation hardening prediction method is characterized by comprising the following steps:
acquiring the chemical free energy density of the nuclear power alloy material according to the Avogardlo constant, the atom molar volume, the defect atom concentration, the defect formation energy, the Boltzmann constant and the absolute temperature of the nuclear power alloy material;
acquiring the elastic free energy density of the nuclear power alloy material based on the crystal plasticity of the nuclear power alloy material;
constructing a thermodynamic system model for representing the evolution of the irradiation defects of the nuclear power alloy material according to the chemical free energy density and the elastic free energy density;
based on the thermodynamic system model, constructing a phase field kinetic model by obtaining the chemical mobility of irradiation point defects, the generation rate of the point defects under irradiation conditions and the concentration of defect atoms of the nuclear power alloy material; obtaining free energy variation according to variation of chemical free energy to components and variation of elastic energy to components; substituting the free energy component into the phase field dynamic model, solving the phase field dynamic model by adopting a semi-implicit Fourier spectrum method, obtaining chemical free energy density, plastic strain and elastic free energy density for next iteration on the basis of the component field obtained by solving and a relation expression model of a stress strain field and plastic strain until the iteration reaches the set additional tensile strain value, and performing radiation hardening prediction on the nuclear power alloy material through MATLAB.
2. The method of claim 1, wherein the step of predicting radiation hardening based on the microstructure comprises:
in the process of obtaining the elastic free energy density, the elastic free energy density is obtained by collecting the elastic constant and the elastic strain tensor of the nuclear power alloy material.
3. The method for predicting radiation hardening based on microstructure according to claim 2, wherein:
and in the process of collecting the elastic strain tensor, collecting the external strain, the non-uniform strain and the intrinsic strain of the nuclear power alloy material to generate the elastic strain tensor.
4. The method of claim 3, wherein the step of predicting radiation hardening based on the microstructure comprises:
in the process of collecting intrinsic strain, acquiring a volume expansion coefficient related to a defect, a defect equilibrium concentration at a certain temperature, a plastic strain tensor and a defect atom concentration, and acquiring a plastic strain tensor used in the intrinsic strain calculation process based on a coupled crystal plasticity theory in phase field simulation.
5. The method of claim 4, wherein the step of predicting radiation hardening based on the microstructure comprises:
in the process of obtaining the plastic strain tensor, the plastic strain tensor is generated by obtaining the number of slip systems, the plastic shear rate of the slip systems, the initial plastic shear rate, the strain sensitivity index, the Schimid tensor factor, the shear stress and the critical shear stress, wherein when the system shear stress is larger than the critical shear stress, slip occurs, and the Schimid tensor factor is obtained by obtaining the slip direction and the normal direction of the slip systems.
6. The method of claim 5, wherein the step of predicting radiation hardening based on the microstructure comprises:
in the process of obtaining the critical shear stress, based on irradiation hardening and strain hardening, a hardening equation is constructed by obtaining the critical shear stress of the nuclear power alloy material when the nuclear power alloy material is not irradiated, an increasing function of the critical shear stress caused after the nuclear power alloy material is irradiated, and an intensity factor related to the defect type, a shear modulus of the material, a Berth vector, a hardening constant, an initial hardening coefficient, a hardening index, a saturated critical shear stress, the density of the defect, and the size of the defect, and the critical shear stress is obtained according to a difference method.
7. The method of claim 6, wherein the step of predicting radiation hardening based on the microstructure comprises:
in the process of constructing a phase field dynamics model, constructing a relation expression model of a stress strain field and plastic strain; the method comprises the steps of obtaining a strain field in a fast Fourier transform mode, obtaining a stress field according to a generalized Hooke law, and obtaining the plastic strain according to the plastic strain tensor.
8. A system for predicting radiation hardening based on a microstructure, comprising:
the chemical free energy density generation module is used for acquiring the chemical free energy density of the nuclear power alloy material according to the Avogardo constant, the atom molar volume, the defect atom concentration, the defect forming energy, the Boltzmann constant and the absolute temperature of the nuclear power alloy material;
the elastic free energy density generating module is used for acquiring the elastic free energy density of the nuclear power alloy material based on the crystal plasticity of the nuclear power alloy material;
the thermodynamic system module is used for constructing a thermodynamic system model for representing the evolution of the irradiation defects of the nuclear power alloy material according to the chemical free energy density and the elastic free energy density;
the irradiation hardening prediction module is used for constructing a phase field dynamics model by acquiring the chemical mobility of irradiation point defects, the generation rate of the point defects under the irradiation condition and the defect atom concentration of the nuclear power alloy material based on the thermodynamic system model; obtaining free energy variation according to variation of chemical free energy to components and variation of elastic energy to components; substituting the free energy component into the phase field dynamic model, solving the phase field dynamic model by adopting a semi-implicit Fourier spectrum method, obtaining chemical free energy density, plastic strain and elastic free energy density for next iteration on the basis of the component field obtained by solving and a relation expression model of a stress strain field and plastic strain until the iteration reaches the set additional tensile strain value, and performing radiation hardening prediction on the nuclear power alloy material through MATLAB.
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