Calculation method for regulating phonon thermal conductivity of Cu-Ni alloy by temperature-composition-irradiation energy coupling

Abstract

The present invention provides a calculation method for regulating the phonon thermal conductivity of a Cu-Ni alloy under the common coupling of temperature-component-irradiation energy, including: using Lammps software to construct a Cu-Ni alloy model, adjusting the Ni content in the Cu-Ni alloy model; using Lammps software to select pka atoms in Cu-Ni alloys with different Ni contents and give them a certain energy, simulating the neutron irradiation process, and analyzing the irradiation defects caused by different pka energies to the Cu-Ni alloy; simulating and calculating the phonon thermal conductivity of three Cu-Ni alloys at different irradiation defect concentrations and different temperatures, and analyzing the influence of temperature and irradiation defect concentration on the phonon thermal conductivity of the Cu-Ni alloy. The present invention simulates and calculates the influence of different temperatures, different components and different irradiation energies on the phonon thermal conductivity of the Cu-Ni alloy by a molecular dynamics method to study the influence of temperature, element changes and defect concentrations on the phonon thermal conductivity of the alloy.

Description

Technical Field

[0001] The invention belongs to the field of research on thermal properties of metal materials, and particularly relates to a calculation method for regulating the phonon thermal conductivity of a Cu-Ni alloy under the common coupling of temperature, component and radiation energy. Background Art

[0002] With the increasing prominence of environmental issues, such as climate change and energy shortages, improving energy efficiency and reducing energy consumption have become particularly important. The thermal conductivity of materials directly affects the efficiency and consumption of energy. In the fields of electronic devices, automobile engines, etc., the use of materials with better thermal conductivity can improve the heat dissipation efficiency of the equipment, thereby reducing energy consumption. For heat transfer components in energy systems, selecting materials with good thermal conductivity can improve the system's thermal energy conversion efficiency and reduce energy waste. By using materials with higher thermal conductivity, heat can be transferred from one place to another more efficiently, thereby reducing energy loss during the transmission process. By studying the thermal transfer performance of materials, it is beneficial to design more effective heat dissipation systems to ensure that the equipment maintains a stable temperature during long-term operation, thereby improving the reliability and stability of the equipment.

[0003] Metals are widely used in industrial applications due to their high heat transfer efficiency, such as in the energy industry, electronics industry, metallurgical industry, and aerospace. Metal Cu plays an important role in wires, cables, electronic equipment, and radiators due to its high electrical conductivity and high thermal conductivity. Cu materials are often used to manufacture radiators, such as CPU radiators, electronic device radiators, etc. The excellent thermal conductivity enables Cu radiators to effectively transfer heat to the external environment and maintain the stable operation of the equipment. Therefore, Cu has important application value in the manufacture of thermal conductive devices, and the devices prepared by it are widely used in industries such as electronics, aerospace, and automobiles. In electronic devices, Cu materials are often used as heat dissipation pads, thermal conductive pastes, etc. to help electronic components dissipate heat, maintain their normal operating temperature, and improve the performance and reliability of the equipment. In general, the research and application of the thermal conductivity of Cu materials is of great significance for improving heat dissipation efficiency, improving the performance of electronic devices, and promoting scientific and technological progress.

[0004] The thermal conductivity of a material consists of two parts, electronic thermal conductivity and phonon thermal conductivity. In metal materials, electronic thermal conductivity is the main contributor, while phonon thermal conductivity is usually ignored. However, the study of phonon thermal conductivity of metals may provide valuable information for their applications in microelectronics and nanoelectronic devices. Adding different types of alloying elements to metal materials may lead to changes in their heat transfer properties, which can provide an effective method for regulating the thermal conductivity of metals.

[0005] In metals, heat transport performance is an important property. Electrons are the main heat carriers, and due to their rapid movement, electronic thermal conductivity is extremely high, and phonon thermal conductivity accounts for only about 5% of the total thermal conductivity. However, under non-equilibrium conditions or in a specific temperature range, phonons may play a certain role, especially when electron scattering is limited. Although the phonon contribution is relatively small, studying phonon thermal conductivity in metals can provide important information about the impact of the material's lattice structure, defects, and impurities on thermal properties. In certain engineering applications, such as electronic devices and thermal conductive devices, phonon thermal conductivity may play an important role in overall thermal conduction, especially at low temperatures and under lattice distortion. By deeply understanding the impact of phonon thermal conductivity, we can fully understand the mechanism of material thermal conductivity and optimize the design and selection of materials for specific applications to achieve better thermal conduction effects. Summary of the invention

[0006] In order to address the deficiencies in the prior art, the present invention provides a calculation method for regulating the phonon thermal conductivity of Cu-Ni alloys under the combined coupling of temperature, component and radiation energy. By using a molecular dynamics method, the effects of different temperatures, different alloy components and different radiation energies on the phonon thermal conductivity of Cu-Ni alloys are simulated and calculated to study the effects of temperature, element changes and defect concentration on the phonon thermal conductivity of the alloy.

[0007] The present invention is achieved through the following technical solutions:

[0008] The present invention provides a calculation method for regulating the phonon thermal conductivity of a Cu-Ni alloy under the combined coupling of temperature, component and radiation energy, the calculation method comprising:

[0009] S1. A CuNi alloy model is constructed using the molecular dynamics software Lammps, in which the CuNi alloy is a substitutional solid solution and has an FCC structure;

[0010] S2. The Ni content in the CuNi alloy model was adjusted by random permutation using Lammps software to obtain three CuNi alloy models with Ni contents of 5 at%, 10 at% and 20 at% respectively;

[0011] S3. Using molecular dynamics method to simulate and calculate the material irradiation damage process: using Lammps software to select pka atoms in the three CuNi alloy models and give certain energies to the pka atoms to simulate the neutron irradiation process, setting irradiation conditions for the simulated neutron irradiation process, keeping the temperature at 300K and the pka direction at

[100] unchanged, selecting different pka energies, and analyzing the irradiation defects caused by different pka energies on the CuNi alloy to obtain defect structures with different concentrations;

[0012] S4. Molecular dynamics method is used to simulate and calculate the phonon thermal conductivity of CuNi alloys: Lammps software is used to simulate and calculate the phonon thermal conductivity of the three CuNi alloys at different temperatures, as well as the phonon thermal conductivity of the three CuNi alloys containing irradiation defects after neutron irradiation stabilization, in order to analyze the influence of different temperatures and different irradiation defect concentrations on the phonon thermal conductivity of CuNi alloys.

[0013] Furthermore, the CuNi alloy model is constructed using the molecular dynamics software Lammps, in which the CuNi alloy is a substitutional solid solution and the crystal structure is an FCC structure, specifically including:

[0014] (1) Determine that the crystal structure of the alloy model is fcc structure;

[0015] (2) Determine the lattice constant of the alloy model:

[0016] (3) The molecular dynamics software Lammps is used to generate a box that meets the conditions (1) and (2). The box has a size of 20a×20a×20a, where a is the lattice constant, and is filled with type 1 Cu atoms.

[0017] (4) Use the set type / ratio command to randomly select atoms from the type 1 Cu atoms, and convert the randomly selected atoms into type 2 Ni atoms to obtain the CuNi alloy model.

[0018] Furthermore, the Lammps software is used to adjust the Ni content in the CuNi alloy model by random permutation to obtain three CuNi alloy models with Ni contents of 5at%, 10at% and 20at%, respectively, specifically including:

[0019] The set type / ratio command of Lammps software was used to randomly convert the type 1 Cu atoms in the CuNi alloy model into type 2 Ni atoms according to a certain ratio, thereby obtaining three CuNi alloy models with Ni contents of 5at%, 10at% and 20at%, respectively.

[0020] Furthermore, the Lammps software is used to select pka atoms in the three CuNi alloy models and to give certain energies to the pka atoms to simulate the neutron irradiation process, specifically including:

[0021] Lammps software was used to select pka atoms in the three CuNi alloy models, and a certain speed was assigned to the pka atoms to simulate the irradiation process of neutrons with corresponding pka energy on the CuNi alloy; wherein the conversion formula between the speed assigned to the pka atoms and the pka energy was: Where E is energy (unit J), m is atomic mass (unit kg), and v is atomic velocity (m / s).

[0022] Furthermore, the irradiation conditions are set for the simulated neutron irradiation process, the temperature is kept at 300K and the pka direction is kept at

[100] direction, different pka energies are selected, and the irradiation defects caused by different pka energies on the CuNi alloy are analyzed to obtain defect structures with different concentrations, specifically including:

[0023] The irradiation conditions are set for the simulated neutron irradiation process, the irradiation temperature is adjusted by the Nose-Hoover hot bath method, the irradiation temperature is controlled at 300K, the irradiation pka energy range is selected from 2keV to 6keV, the energy interval of different pka energies is 2keV, the irradiation crystal direction is selected from the

[100] direction, and Lammps software is used to perform computational simulation of the irradiation damage of the CuNi alloy. In the process of calculating the irradiation damage of the CuNi alloy, the potential function used is the FeCuNi-with-ZBL.eam.alloy potential, and the ovtio software is used for visualization, and the irradiation defects caused by different pka energies on the CuNi alloy are analyzed to obtain defect structures containing different concentrations.

[0024] Furthermore, the Lammps software is used to simulate and calculate the phonon thermal conductivity of the three CuNi alloys at different temperatures, and the phonon thermal conductivity of the three CuNi alloys containing irradiation defects after neutron irradiation stabilization, so as to analyze the influence of different temperatures and different irradiation defect concentrations on the phonon thermal conductivity of the CuNi alloy, specifically including:

[0025] Lammps software was used to simulate and calculate the phonon thermal conductivity of the three CuNi alloys at different temperatures, as well as the phonon thermal conductivity of the three CuNi alloys containing irradiation defects after neutron irradiation stabilization. The equilibrium molecular dynamics (EMD) method was used in the calculation of the phonon thermal conductivity, and the potential function used was CuNi_v2.eam.alloy potential. The temperature was adjusted by the Nose-Hoover heat bath method, the nve ensemble was used, and the time step was 0.001ps. The atomic coordinate information, temperature, heat flow and thermal conductivity were output to analyze the influence of temperature and irradiation defect concentration on the phonon thermal conductivity of the CuNi alloy. In this process, the non-irradiated was used as the control group to observe the influence of defects on the phonon thermal conductivity of the material after irradiation.

[0026] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0027] The present invention provides a calculation method for regulating the phonon thermal conductivity of a Cu-Ni alloy under the common coupling of temperature, component and radiation energy. It is expected that by studying the influence of the common coupling of temperature, component and radiation energy on the phonon thermal conductivity of the Cu-Ni alloy, three CuNi alloy models with different Ni contents are constructed by molecular dynamics software Lammps, and the influence of radiation defects on the CuNi alloy under different pka energy radiation is calculated and simulated to obtain defect structures with different concentrations, and then the changes of phonon thermal conductivity of the CuNi alloys with three Ni contents under different temperatures and different radiation defect concentrations are simulated and calculated to analyze the influence of temperature and defect concentration on the phonon thermal conductivity of the alloy. The present invention adopts open source software Lammps for molecular dynamics calculation, provides a method for regulating the generation and evolution process of defects with different radiation energies from the perspective of designing alloy composition and structure, thereby obtaining defect structures with different concentrations, and further analyzing the influence of temperature, element change and defect concentration on the phonon thermal conductivity of the alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 Cu-Ni alloy structure with different proportions of Cu and Ni element.

[0030] Figure 2 is the normalized heat flow autocorrelation function of Cu at different temperatures.

[0031] Figure 3 This is the curve of the phonon thermal conductivity of Cu changing with temperature.

[0032] Figure 4 The phonon thermal conductivity of Cu and its Cu-Ni alloy in the x, y, and z directions at 300K varies with time.

[0033] Figure 5 is the normalized heat flow autocorrelation function of Cu-Ni alloys with different Ni contents at 300K.

[0034] Figure 6 is the normalized heat flow autocorrelation function of Cu-Ni alloys with different Ni contents at 1300K.

[0035] Figure 7The curves of phonon thermal conductivity of Cu-Ni alloys with different Ni contents varying with temperature.

[0036] Figure 8 This is the curve showing the variation of defect number over time for Cu-Ni alloys with different Ni contents under different irradiation energies.

[0037] Fig. 9 Phonon thermal conductivity variation curve of Cu-Ni alloys with different Ni contents under different irradiation energies. DETAILED DESCRIPTION

[0038] The present invention will be described in detail below in conjunction with specific implementations and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific implementations and examples are used to illustrate the present invention, rather than to limit the present invention.

[0039] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. In the event of a conflict, the present specification takes precedence.

[0040] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0041] The overall idea of ​​the present invention is as follows:

[0042] The thermal conductivity of materials consists of two parts, the thermal conductivity contribution is composed of electrons and phonons (lattice vibrations that carry energy). For non-metallic or dielectric materials, such as ceramics and glass, the transfer of heat conduction is mainly through phonon vibrations. In contrast to non-metallic and dielectric materials, heat in metals is mainly transferred by electrons, and the contribution from phonons has always been ignored. Molecular dynamics (MD) is a tool that uses computational simulation to study complex systems at the atomic level. The use of MD has achieved great success in the field of thermal conduction. There are two main methods for calculating the thermal conductivity of materials, one is the non-equilibrium molecular dynamics (NEMD) method, and the other is the equilibrium molecular dynamics (EMD) method. Both methods have been proven to be able to calculate the thermal conductivity of a variety of materials. For metals, the material phonon thermal conductivity can be accurately calculated.

[0043] For the phonon thermal conductivity of Cu, at different temperatures, the phonon thermal conductivity will decrease with the increase of temperature. When a second phase alloying element is added to metal Cu, the phonon thermal conductivity will change with the change of the concentration of the alloying element. The influence of vacancy defects and interstitial defects on the thermal transport of the material under irradiation defects has not been considered. Due to the influence of the environment during the use of the material, various defect structures will be formed in the material, and the existence of the defect structure will further affect the phonon thermal conductivity. So far, there are few research results in the field of phonon thermal conduction of metals and their alloys, and the factors affecting the thermal conductivity of the material are not considered comprehensively, especially the introduction of second phase elements (element concentration) and the existence of irradiation defects (vacancies and interstitial defects) in the metal. The mechanism of the influence of the metal phonon thermal conductivity is still unclear, so the study of the influence of the microstructure of the material on the thermal transport properties of the material has attracted widespread attention. Cu has received widespread attention because of its high electrical conductivity and high thermal conductivity. The thermal conductivity of metal Cu at room temperature is as high as 398-401W / mk. Therefore, the present invention studies the influence of temperature-component-irradiation energy on phonon thermal conductivity in Cu-based alloys under the combined coupling effect of temperature-component-irradiation energy. It is of great significance.

[0044] Specifically, the present invention provides a calculation method for regulating the phonon thermal conductivity of a Cu-Ni alloy under the combined coupling of temperature, composition, and radiation energy, including:

[0045] S1. The molecular dynamics software Lammps is used to construct a CuNi alloy model. In the CuNi alloy model, the CuNi alloy is a substitutional solid solution and the crystal structure is an FCC structure, as follows:

[0046] Determine the crystal structure of the alloy model as fcc structure, lattice constant: The molecular dynamics software Lammps was used to generate a box of fcc structure with a size of 20a×20a×20a, where a is the lattice constant, and the box was filled with type 1 Cu atoms. The set type / ratio command was used to randomly select atoms from the type 1 Cu atoms, and the randomly selected atoms were converted into type 2 Ni atoms to obtain a CuNi alloy model.

[0047] S2. Lammps software was used to adjust the Ni content in the CuNi alloy model by random permutation to obtain three CuNi alloy models with Ni contents of 5at%, 10at% and 20at%, respectively, as follows:

[0048] The set type / ratio command in the lammps software is used to randomly permute atoms. The syntax of set type / ratio is: set type / ratio type_ID type / ratio type_new fraction seed.

[0049] Where: Cu-5at%Ni is: set type 1type / ratio 2 0.05 873931;

[0050] Cu-10at%Ni is: set type 1type / ratio 2 0.1 873931;

[0051] Cu-20at%Ni is: set type 1type / ratio 2 0.2 873931.

[0052] S3. Use molecular dynamics method to simulate and calculate the material radiation damage process:

[0053] Lammps software was used to select pka atoms in the three CuNi alloy models, and a certain speed was assigned to the pka atoms to simulate the irradiation process of neutrons with corresponding pka energy on the CuNi alloy; wherein the conversion formula between the speed assigned to the pka atoms and the pka energy was: Where E is energy (unit J), m is atomic mass (unit kg), and v is atomic velocity (m / s).

[0054] In the above simulation process, the atomic velocity v is The conversion quantities involved are: 1ev=1.6×10 -19 J;

[0055] The irradiation conditions are set for the simulated neutron irradiation process, the temperature is kept at 300K and the pka direction is

[100] direction unchanged, different pka energies are selected, and the irradiation defects caused by different pka energies on the CuNi alloy are analyzed to obtain defect structures containing different concentrations: the irradiation temperature is adjusted by the Nose-Hoover hot bath method, the irradiation temperature is controlled at 300K, the irradiation pka energy range is selected from 2keV to 6keV, and the energy interval is 2keV. In the CuNi alloy model, the pka direction can be controlled by setting different crystal orientations for xyz. The irradiation crystal orientation of the present invention selects the

[100] direction. In the process of calculating the irradiation damage of the CuNi alloy, the potential function used is the FeCuNi-with-ZBL.eam.alloy potential, Lammps software is used to perform calculation simulation of the irradiation damage, and ovtio software is used for visualization. The irradiation defects caused to the CuNi alloy under different pka energy irradiation conditions are analyzed to obtain defect structures containing different concentrations.

[0056] The regulation of pka energy is achieved by changing the speed assigned to the pka atoms, and the irradiation pka energy is selected as 2keV, 4keV, and 6keV.

[0057] S4. Molecular dynamics method is used to simulate and calculate the phonon thermal conductivity of CuNi alloy:

[0058] Lammps software was used to simulate and calculate the phonon thermal conductivity of the three CuNi alloys at different temperatures, as well as the phonon thermal conductivity of the three CuNi alloys containing different concentrations of irradiation defects after neutron irradiation stabilization, and the influence of temperature and defect concentration on the phonon thermal conductivity of the alloy was analyzed. Specifically, the equilibrium molecular dynamics (EMD) method was used in this process, the potential function used was CuNi_v2.eam.alloy potential, the temperature was adjusted by the Nose-Hoover heat bath method, the nve ensemble was used, the time step was 0.001ps, and the atomic coordinate information, temperature, heat flow and thermal conductivity were output every 100,000 steps during this period to analyze the influence of temperature and defect concentration on the phonon thermal conductivity of the alloy. In this process, the non-irradiated was used as a control group to observe the influence of defects on the phonon thermal conductivity of the material after irradiation.

[0059] The following will describe in detail the calculation method of regulating the phonon thermal conductivity of Cu-Ni alloy under the combined coupling of temperature, composition and radiation energy in the present application in combination with the embodiments and experimental data.

[0060] The present invention adopts a calculation method for regulating the phonon thermal conductivity of Cu-Ni alloy under the common coupling of temperature-component-irradiation energy, adopts a molecular dynamics method, and applies open source software Lammps for simulation calculation. When the calculation results are post-processed, it is necessary to use other software to complete modeling and analysis. OVITO is an open source software for data visualization and analysis, which can convert atomic coordinates into meaningful graphics, and observe the movement trajectory of atoms more clearly by staining or slicing according to information variables. It can be used as a software for output data of molecular dynamics (MD) simulation of solid materials. The present invention adopts the equilibrium molecular dynamics (EMD) method. The calculated output data needs to be further drawn and analyzed in origin. In the process of calculating the phonon thermal conductivity simulation, Cu_mishin1.eam.alloy and CuNi_v2.eam.alloy potentials are selected for Cu and Cu-Ni alloy potential functions respectively.

[0061] Example 1

[0062] like Figure 1 The following is a Cu-Ni alloy model with different Ni contents, and the space group is Fm3m. FCC structure with an angle of 90°. Lammps software was used for modeling, and a 20a×20a×20a model with a total of 32,000 atoms was established as the initial model. This model was established according to a rational lattice arrangement. In actual simulations, this model is not stable and must be relaxed. In order to perform molecular dynamics relaxation, the initial model was run under the isothermal and isobaric (NPT) ensemble for 500,000 steps with a time step of 0.001ps, that is, the relaxation was performed for 500ps to obtain a stable model. It was then visualized in ovito. Figure 1 .

[0063] like Figure 2 , 3 The following are the normalized heat flow autocorrelation function and phonon thermal conductivity of Cu at different temperatures. The equilibrium molecular dynamics (EMD) method is used to calculate the phonon thermal conductivity in lammps. The potential function used is Cu_mishin1.eam.alloy potential. The temperature is adjusted by the Nose-Hoover heat bath method. The nve ensemble is used. The time step is 0.001ps. During this period, the atomic coordinate information, temperature, heat flow and thermal conductivity are output every 100,000 steps.

[0064] During the analysis process, the data obtained from the simulation calculation is processed in Origin and graphed. Figure 2The normalized heat flow autocorrelation function (HCACF) of pure copper at 300K, 500K, 700K, and 1300K was plotted to study how different temperatures affect HCACF. Before decaying to zero, the HCACF at 300K, 500K, and 700K go through three stages: a rapid decline stage, a fluctuation stage, and a slow decline stage. However, the HCACF at 1300K has only two stages: a rapid decline stage and a slow decline stage. After the rapid decline in the first stage, the HCACF at 300K, 500K, and 700K increases, and the increase at 300K is higher than that at 500K and 700K. However, for 1300K, the second stage turns into a plateau. Finally, the HCACF at 300K, 500K, and 700K slowly decreases to zero, accompanied by fluctuations, and the curve becomes smooth as the temperature increases. From this we can conclude that: at low temperatures, the heat flow autocorrelation function will have a peak, indicating that the heat flow fluctuations between particles are more obvious on a smaller time scale. As the temperature increases, the peak of the heat flow autocorrelation function becomes flat, indicating that as the temperature increases, the thermal motion inside the material intensifies, the movement range of the particles expands, and the correlation weakens.

[0065] Figure 3 The phonon thermal conductivity of pure Cu is plotted as a function of temperature. As shown in the figure, the phonon thermal conductivity has a clear downward trend with increasing temperature, and the trend becomes gentler as the temperature rises. The phonon thermal conductivity decreases by 86.67% when the temperature rises from 300K to 1300K.

[0066] Example 2

[0067] like Figure 1 Shown is a CuNi alloy model with different Ni contents, which has an FCC structure with a space group of Fm3m. The obtained CuNi alloy model is used to calculate the change in phonon thermal conductivity of CuNi alloy at different temperatures. In this process, the Cu-Ni alloy potential function selects CuNi_v2.eam.alloy potential. The temperature is controlled at 300K, 500K, 700K, and 1300K by the Nose-Hoover heat bath method. To ensure the calculation accuracy, the simulation system uses a microcanonical ensemble (NVE). The thermal conductivity calculation process lasts 15,000,000 steps with a time step of 0.001ps, that is, it runs for 15,000ps. During this period, the heat flow and thermal conductivity information in the three directions of xyz are output every 100,000 steps. The data obtained by the calculation is plotted in origin as shown below. Figure 4 , 5 , 6, and 7 show the curve changes.

[0068] Take the model at 300K as an example. Figure 4The phonon thermal conductivity in the x, y, and z directions at 300K is plotted as a function of time. In the initial stage, the phonon thermal conductivity changes dramatically until the simulation time reaches about 8000ps, after which the thermal conductivity remains stable. Therefore, the simulation time must be greater than 8000ps to ensure the accuracy of the results. The changes in the phonon thermal conductivity of the CuNi alloy at different temperatures are then calculated. Figure 5 , 6 The following are the normalized heat flow autocorrelation functions of CuNi alloys with different Ni contents at 300K and 1300K. It can be seen from the figure that with the introduction of Ni atoms, HCACF has undergone continuous oscillations from the original fluctuations, and the amplitude of the oscillation increases with the increase of Ni content. For the HCACF value, as the Ni content increases, the decay rate is faster in the rapid decline stage. Figure 7 The figure shows the relationship between the phonon thermal conductivity of CuNi alloys with different Ni contents and temperature. It can be seen from the figure that for CuNi alloys with the same Ni content, as the temperature increases, the phonon thermal conductivity of the alloy shows a downward trend. Under the same temperature conditions, as the Ni content increases, the phonon thermal conductivity of the CuNi alloy decreases. As the temperature increases, the effect of temperature on thermal conductivity gradually weakens. At the same time, when the temperature is high, the effect of increasing Ni content on the thermal conductivity of the alloy becomes smaller and smaller.

[0069] Example 3

[0070] In order to study the influence of defects on the thermal conductivity of materials, the three Cu-Ni alloy models were irradiated at different pka energies to form alloy models with different defect concentrations. The irradiation conditions were set for the simulated neutron irradiation process, the temperature was kept at 300K and the pka direction was

[100] direction unchanged, different pka energies were selected, and the irradiation defects caused by different pka energies on the CuNi alloy were analyzed. The irradiation temperature was adjusted by the Nose-Hoover hot bath method, and the irradiation temperature was controlled at 300K. The irradiation pka energy range was selected from 2keV to 6keV, and the energy interval was 2keV. In the process of calculating the irradiation damage of the CuNi alloy, the potential function used was FeCuNi-with-ZBL.eam.alloy potential, and Lammps software was used to simulate the calculation of irradiation damage. Finally, ovtio software was used for visualization, and the number of irradiation defects caused to the CuNi alloy under different pka energy irradiation conditions was analyzed to obtain defect structures with different concentrations.

[0071] The neutron irradiation process generally goes through three stages. The number of point defects first increases, then decreases, and finally stabilizes, which corresponds to the ballistic phase, recombination phase, and stable phase in the cascade collision. Since interstitial atoms and vacancies always exist in pairs (i.e., Frenkel defect pairs) in cascade collisions, we count the number of Frenkel defect pairs at the final stability to examine the impact on phonon thermal conductivity. Figure 8 The figure shows the change of defect number over time under different pka energy irradiation. The irradiation temperature was controlled at 300K by the Nose-Hoover hot bath method, and 2keV, 4keV, and 6keV were selected as irradiation conditions. The initial model was run for 20,000 steps in the isothermal and isobaric (NPT) ensemble, with a time step of 0.001ps, that is, relaxation for 20ps. Then, a certain speed was given to the selected pka atoms, and cascade collisions were carried out in the microcanonical (NVE) ensemble. The cascade collision process lasted for 20ps. Figure 8 It can be clearly seen that with the increase of PKA energy, the number of Frenkel defect pairs generated at the defect peak increases significantly. Subsequently, the number of Frenkel defect pairs decreases rapidly. With the increase of PKA energy, the number of Frenkel defect pairs formed also increases gradually, and finally a Cu-Ni alloy model with different defect concentrations is obtained.

[0072] The effects of temperature and defects on the phonon thermal conductivity of the alloy were further studied. Lammps software was used to simulate and calculate the phonon thermal conductivity of the three CuNi alloys at different temperatures, as well as the phonon thermal conductivity of the three CuNi alloys containing different concentrations of irradiated defects after neutron irradiation stabilization, to analyze the effects of temperature and defect concentration on the phonon thermal conductivity of the alloy. In this process, the equilibrium molecular dynamics (EMD) method was used, the potential function used was CuNi_v2.eam.alloy potential, the temperature was adjusted by the Nose-Hoover heat bath method, the nve ensemble was used, the time step was 0.001ps, and the atomic coordinate information, temperature, heat flow and thermal conductivity were output every 100,000 steps to analyze the effects of temperature and defect concentration on the phonon thermal conductivity of the alloy. In this process, the non-irradiated was used as the control group to observe the effect of defects on the phonon thermal conductivity of the material after irradiation.

[0073] like Fig. 9 The figure shows the relationship between the changes in phonon thermal conductivity of the three Cu-Ni alloys under different irradiation energies. Among them, 0keV represents the unirradiated Cu-Ni alloy. It can be seen from the figure that with the increase of defect concentration, the phonon thermal conductivity decreases significantly.

[0074] Finally, it should be noted that the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article, or apparatus.

[0075] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0076] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these 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 these modifications and variations.

Claims

1. A calculation method for regulating the phonon thermal conductivity of Cu-Ni alloy by the combined effect of temperature, composition and radiation energy, characterized in that: The calculation method includes: S1. A CuNi alloy model is constructed using the molecular dynamics software Lammps, in which the CuNi alloy is a substitutional solid solution and has an FCC structure; S2. The Ni content in the CuNi alloy model was adjusted by random permutation using Lammps software to obtain three CuNi alloy models with Ni contents of 5 at%, 10 at% and 20 at% respectively; S3. Using molecular dynamics method to simulate and calculate the material irradiation damage process: using Lammps software to select pka atoms in the three CuNi alloy models and give certain energies to the pka atoms to simulate the neutron irradiation process, setting irradiation conditions for the simulated neutron irradiation process, keeping the temperature at 300K and the pka direction at [100] unchanged, selecting different pka energies, and analyzing the irradiation defects caused by different pka energies on the CuNi alloy to obtain defect structures with different concentrations; S4. The molecular dynamics method is used to simulate and calculate the phonon thermal conductivity of the CuNi alloy: Lammps software is used to simulate and calculate the phonon thermal conductivity of the three CuNi alloys at different temperatures, and the phonon thermal conductivity of the three CuNi alloys containing irradiation defects after neutron irradiation stabilization, so as to analyze the influence of different temperatures and different irradiation defect concentrations on the phonon thermal conductivity of the CuNi alloy; The CuNi alloy model is constructed by using the molecular dynamics software Lammps. In the CuNi alloy model, the CuNi alloy is a substitutional solid solution and the crystal structure is an FCC structure, which specifically includes: (1) Determine that the crystal structure of the alloy model is fcc structure; (2) Determine the lattice constant of the alloy model: (3) Molecular dynamics software Lammps is used to generate a box that meets the conditions (1) and (2). The box has a size of 20a×20a×20a, where a is the lattice constant, and is filled with type 1 Cu atoms. (4) Use the set type / ratio command to randomly select atoms from the type 1 Cu atoms, and convert the randomly selected atoms into type 2 Ni atoms to obtain a CuNi alloy model; The Lammps software is used to simulate and calculate the phonon thermal conductivity of the three CuNi alloys at different temperatures, and the phonon thermal conductivity of the three CuNi alloys containing irradiation defects after neutron irradiation stabilization, so as to analyze the influence of different temperatures and different irradiation defect concentrations on the phonon thermal conductivity of the CuNi alloy, specifically including: Lammps software was used to simulate and calculate the phonon thermal conductivity of the three CuNi alloys at different temperatures, as well as the phonon thermal conductivity of the three CuNi alloys containing irradiation defects after neutron irradiation stabilization. The equilibrium molecular dynamics method was used in the calculation of the phonon thermal conductivity. The potential function used was CuNi_v2.eam.al loy potential. The temperature was adjusted by the Nose-Hoover heat bath method. The nve ensemble was used with a time step of 0.001ps. The atomic coordinate information, temperature, heat flow and thermal conductivity were output to analyze the influence of temperature and irradiation defect concentration on the phonon thermal conductivity of the CuNi alloy.

2. The calculation method for regulating the phonon thermal conductivity of Cu-Ni alloy by the temperature-composition-irradiation energy coupling according to claim 1 is characterized in that: The Lammps software is used to adjust the Ni content in the CuNi alloy model by random permutation to obtain three CuNi alloy models with Ni contents of 5at%, 10at% and 20at%, respectively, specifically comprising: The set type / ratio command of Lammps software was used to randomly convert the type 1 Cu atoms in the CuNi alloy model into type 2 Ni atoms according to a certain ratio, thereby obtaining three CuNi alloy models with Ni contents of 5at%, 10at% and 20at%, respectively.

3. The calculation method for regulating the phonon thermal conductivity of Cu-Ni alloy by the temperature-composition-irradiation energy coupling according to claim 1 is characterized in that: The Lammps software is used to select pka atoms in the three CuNi alloy models and to give certain energies to the pka atoms to simulate the neutron irradiation process, specifically including: Lammps software was used to select pka atoms in the three CuNi alloy models, and a certain speed was assigned to the pka atoms to simulate the irradiation process of neutrons with corresponding pka energy on the CuNi alloy; wherein the conversion formula between the speed assigned to the pka atoms and the pka energy was: Where E is energy in J, m is atomic mass in kg, and v is atomic velocity in m / s.

4. The calculation method for regulating the phonon thermal conductivity of Cu-Ni alloy by the temperature-composition-irradiation energy coupling according to claim 1 is characterized in that: The irradiation conditions are set for the simulated neutron irradiation process, the temperature is kept at 300K and the pka direction is kept at [100] direction, different pka energies are selected, and the irradiation defects caused by different pka energies on the CuNi alloy are analyzed to obtain defect structures with different concentrations, specifically including: The irradiation conditions are set for the simulated neutron irradiation process, the irradiation temperature is adjusted by the Nose-Hoover hot bath method, the irradiation temperature is controlled at 300K, the irradiation pka energy range is selected from 2keV to 6keV, the energy interval of different pka energies is 2keV, the irradiation crystal direction is selected from the [100] direction, and Lammps software is used to perform computational simulation of the irradiation damage of the CuNi alloy. In the process of calculating the irradiation damage of the CuNi alloy, the potential function used is the FeCuNi-with-ZBL.eam.al loy potential, and ovtio software is used for visualization, and the irradiation defects caused by different pka energies on the CuNi alloy are analyzed to obtain defect structures containing different concentrations.

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