One of the major tasks in a molecular dynamics (MD) simulation is the selection of adequate potential functions, from which forces are derived. If the potentials do not model the behaviour of the atoms correctly, th...One of the major tasks in a molecular dynamics (MD) simulation is the selection of adequate potential functions, from which forces are derived. If the potentials do not model the behaviour of the atoms correctly, the results produced from the simulation would be useless. Three popular potentials, namely, Lennard-Jones (L J), Morse, and embedded-atom method (EAM) potentials, were employed to model copper workpiece and diamond tool in nanometric machining. From the simulation results and further analysis, the EAM potential was found to be the most suitable of the three potentials. This is because it best describes the metallic bonding of the copper atoms; it demonstrated the lowest cutting force variation, and the potential energy is most stable for the EAM.展开更多
Motivated by the special theory of gradient elasticity (GradEla), a proposal is advanced for extending it to construct gradient models for interatomic potentials, commonly used in atomistic simulations. Our focus is o...Motivated by the special theory of gradient elasticity (GradEla), a proposal is advanced for extending it to construct gradient models for interatomic potentials, commonly used in atomistic simulations. Our focus is on London’s quantum mechanical potential which is an analytical expression valid until a certain characteristic distance where “attractive” molecular interactions change character and become “repulsive” and cannot be described by the classical form of London’s potential. It turns out that the suggested internal length gradient (ILG) generalization of London’s potential generates both an “attractive” and a “repulsive” branch, and by adjusting the corresponding gradient parameters, the behavior of the empirical Lennard-Jones potentials is theoretically captured.展开更多
Al,Ca,and Zn are representative commercial alloying elements for Mg alloys.To investigate the effects of these elements on the deformation and recrystallization behaviors of Mg alloys,we develop interatomic potentials...Al,Ca,and Zn are representative commercial alloying elements for Mg alloys.To investigate the effects of these elements on the deformation and recrystallization behaviors of Mg alloys,we develop interatomic potentials for the Al-Ca,Al-Zn,Mg-Al-Ca and Mg-Al-Zn systems based on the second nearest-neighbor modified embedded-atom method formalism.The developed potentials describe structural,elastic,and thermodynamic properties of compounds and solutions of associated alloy systems in reasonable agreement with experimental data and higher-level calculations.The applicability of these potentials to the present investigation is confirmed by calculating the generalized stacking fault energy for various slip systems and the segregation energy on twin boundaries of the Mg-Al-Ca and Mg-Al-Zn alloys,accompanied with the thermal expansion coefficient and crystal structure maintenance of stable compounds in those alloys.展开更多
The lattice-inversion embedded-atom-method interatomic potential developed previously by us is extended to alkaline metals including Li,Na,and K.It is found that considering interatomic interactions between neighborin...The lattice-inversion embedded-atom-method interatomic potential developed previously by us is extended to alkaline metals including Li,Na,and K.It is found that considering interatomic interactions between neighboring atoms of an appropriate distance is a matter of great significance in constructing accurate embedded-atom-method interatomic potentials,especially for the prediction of surface energy.The lattice-inversion embedded-atom-method interatomic potentials for Li,Na,and K are successfully constructed by taking the fourth-neighbor atoms into consideration.These angular-independent potentials markedly promote the accuracy of predicted surface energies,which agree well with experimental results.In addition,the predicted structural stability,elastic constants,formation and migration energies of vacancy,and activation energy of vacancy diffusion are in good agreement with available experimental data and first-principles calculations,and the equilibrium condition is satisfied.展开更多
We applied an approach to the development of many-body interatomic potentials for NiZr alloys,gaining an improved accuracy and reliability.The functional form of the potential is that of the embedded method,but it has...We applied an approach to the development of many-body interatomic potentials for NiZr alloys,gaining an improved accuracy and reliability.The functional form of the potential is that of the embedded method,but it has been improved as follows. (1) The database used for the development of the potential includes both experimental data and a large set of energies of different structures of the alloys generated by Fab initio calculations. (2) The optimum parametrization of the potential for the given database is obtained by fitting. Using this approach we developed reliable interatomic potentials for Ni and Zr. The potential accurately reproduces basic equilibrium properties of the alloys.展开更多
Carbon neutrality has been proposed as a solution for the current severe energy and climate crisis caused by the overuse of fossil fuels, and machine learning(ML) has exhibited excellent performance in accelerating re...Carbon neutrality has been proposed as a solution for the current severe energy and climate crisis caused by the overuse of fossil fuels, and machine learning(ML) has exhibited excellent performance in accelerating related research owing to its powerful capacity for big data processing. This review presents a detailed overview of ML accelerated carbon neutrality research with a focus on energy management, screening of novel energy materials, and ML interatomic potentials(MLIPs), with illustrations of two selected MLIP algorithms: moment tensor potential(MTP) and neural equivariant interatomic potential(NequIP). We conclude by outlining the important role of ML in accelerating the achievement of carbon neutrality from global-scale energy management, unprecedented screening of advanced energy materials in massive chemical space, to the revolution of atomicscale simulations of MLIPs, which has the bright prospect of applications.展开更多
The structure and properties of materials under neutron irradiation are an important basis in future fusion reactors.In the absence of fusion neutron sources for irradiation experiments,it is increasingly important an...The structure and properties of materials under neutron irradiation are an important basis in future fusion reactors.In the absence of fusion neutron sources for irradiation experiments,it is increasingly important and urgent to carry out neutron irradiation simulations on fusion reactor materials and then establish complete databases of defect properties and collisional cascades,where the first and foremost step is to select suitable interatomic potentials for atomistic-level simulations.In this work,six typic interatomic potentials for tungsten(W)are evaluated and reviewed systematically for radiation damage simulations.The relative lattice stability and elastic constants of bulk W are considered first with those potentials;then,the properties of point defects and defect clusters at interstitial sites and vacancies are obtained by molecular statics/dynam-ics simulations.The formation energies of interstitial/vacancy clusters,1/2<111>and<100>dislocation loops in W and the threshold displacement energies along different directions are also determined.In addition,the extended defects are further investigated,such as free surfaces and the energy profiles of 1/2<111>{110}and 1/2<111>{112}stacking faults.The current results provide a reference for selecting W potentials to simulate the radiation damage.展开更多
In this paper, we deduce the analytical form of many-body interatomic potentials based on the Green's function in tight-binding representation. The many-body potentials are expressed as the functions of the hoppin...In this paper, we deduce the analytical form of many-body interatomic potentials based on the Green's function in tight-binding representation. The many-body potentials are expressed as the functions of the hopping integrals which are the physical origin of cohesion of atoms. For thesimple case of s-valent system, the inversion of the many-body potentials are discussed in detail by using the lattice inversion method.展开更多
This paper summarizes the progress of machine-learning-based interatomic potentials and their applications in advanced manufacturing.Interatomic potential is essential for classical molecular dynamics.The advancements...This paper summarizes the progress of machine-learning-based interatomic potentials and their applications in advanced manufacturing.Interatomic potential is essential for classical molecular dynamics.The advancements made in machine learning(ML)have enabled the development of fast interatomic potential with ab initio accuracy.The accelerated atomic simulation can greatly transform the design principle of manufacturing technology.The most widely used supervised and unsupervised ML methods are summarized and compared.Then,the emerging interatomic models based on ML are discussed:Gaussian approximation potential,spectral neighbor analysis potential,deep potential molecular dynamics,SCHNET,hierarchically interacting particle neural network,and fast learning of atomistic rare events.展开更多
The investigation of thermal transport is crucial to the thermal management of modern electronic devices.To obtain the thermal conductivity through solution of the Boltzmann transport equation,calculation of the anhar...The investigation of thermal transport is crucial to the thermal management of modern electronic devices.To obtain the thermal conductivity through solution of the Boltzmann transport equation,calculation of the anharmonic interatomic force constants has a high computational cost based on the current method of single-point density functional theory force calculation.The recent suggested machine learning interatomic potentials(MLIPs)method can avoid these huge computational demands.In this work,we study the thermal conductivity of two-dimensional MoS_(2)-like hexagonal boron dichalcogenides(H-B_(2)VI_(2);V I=S,Se,Te)with a combination of MLIPs and the phonon Boltzmann transport equation.The room-temperature thermal conductivity of H-B_(2)S_(2)can reach up to 336 W·m^(-1)·K^(-1),obviously larger than that of H-B_(2)Se_(2)and H-B_(2)Te_(2).This is mainly due to the difference in phonon group velocity.By substituting the different chalcogen elements in the second sublayer,H-B_(2)VIV I′have lower thermal conductivity than H-B_(2)VI_(2).The room-temperature thermal conductivity of B2STe is only 11%of that of H-B_(2)S_(2).This can be explained by comparing phonon group velocity and phonon relaxation time.The MLIP method is proved to be an efficient method for studying the thermal conductivity of materials,and H-B_(2)S_(2)-based nanodevices have excellent thermal conduction.展开更多
To shed a light on Xe bubble nucleation in U–Mo fuel from the view of primary irradiation damage,a reported U–Mo–Xe potential under the framework of embedded atom method has been modified within the range of short ...To shed a light on Xe bubble nucleation in U–Mo fuel from the view of primary irradiation damage,a reported U–Mo–Xe potential under the framework of embedded atom method has been modified within the range of short and intermediate atomic distance.The modified potential can better describe the interactions between energetic particles,and can accurately reproduce the threshold displacement energy surface calculated by the first-principles method.Then,molecular dynamics simulations of primary irradiation damage in U–Mo–Xe system have been conducted under different contents.The raise of Xe concentration brings about a remarkable promotion in residual defect quantity and generates bubbles in more overpressured state,which suggests an acceleration of irradiation damage under the accumulation of the fission gas.Meanwhile,the addition of Mo considerably reduces the residual defect count and hinders irradiation-induced Xe diffusion especially at high contents of Xe,corroborating the importance of high Mo content in mitigation of irradiation damage and swelling behavior in U–Mo fuel.In particular,the variation of irradiation damage with respect to contents suggests a necessity of taking into account the influence of local components on defect evolution in mesoscale simulations.展开更多
So far, it has been a challenge for existing interatomic potentials to accurately describe a wide range of physical properties and maintain reasonable efficiency. In this work, we develop an interatomic potential for ...So far, it has been a challenge for existing interatomic potentials to accurately describe a wide range of physical properties and maintain reasonable efficiency. In this work, we develop an interatomic potential for simulating radiation damage in body-centered cubic tungsten by employing deep potential, a neural network-based deep learning model for representing the potential energy surface. The resulting potential predicts a variety of physical properties consistent with first-principles calculations, including phonon spectrum, thermal expansion, generalized stacking fault energies, energetics of free surfaces, point defects, vacancy clusters, and prismatic dislocation loops. Specifically, we investigated the elasticity-related properties of prismatic dislocation loops, i.e., their dipole tensors, relaxation volumes, and elastic interaction energies. This potential is found to predict the maximal elastic interaction energy between two 1/2 <1 1 1> loops better than previous potentials, with a relative error of only 7.6%. The predicted threshold displacement energies are in reasonable agreement with experimental results, with an average of 128 eV. The efficiency of the present potential is also comparable to the tabulated gaussian approximation potentials and modified embedded atom method potentials, meanwhile, can be further accelerated by graphical processing units. Extensive benchmark tests indicate that this potential has a relatively good balance between accuracy, transferability, and efficiency.展开更多
The effects of Fe substitution for Co on the structural stability and the site preference of intermetallics Nd2CoT-xFex with a hexagonal Ce2NiT-type structure are studied by using a series of interatomic pair potentia...The effects of Fe substitution for Co on the structural stability and the site preference of intermetallics Nd2CoT-xFex with a hexagonal Ce2NiT-type structure are studied by using a series of interatomic pair potentials. In Nd2CoT-xFex, Fe atoms are substituted for Co atoms with a strong preference for the 6h sites and the order of site preference is 6h, 4e, 4f, 2a, and 12k. Calculated lattice parameters are found to be consistent with the reported results in the literature. The variation behaviour of the Curie temperature of Nd2CoT-xFex is explained qualitatively by the exchange interaction model. The properties related to lattice vibration, such as phonon density of states and Debye temperature, are first evaluated for the Nd2Co7 xFex compounds.展开更多
This paper investigates the structural stability of intermetallics R3Ni13-xCoxB2 (R=Y, Nd and Sm) with Nd3Ni13B2-type structure and the site preferences of the transition element Co by using a series of interatomic ...This paper investigates the structural stability of intermetallics R3Ni13-xCoxB2 (R=Y, Nd and Sm) with Nd3Ni13B2-type structure and the site preferences of the transition element Co by using a series of interatomic pair potentials. The space group remains unchanged upon substitution of Co for Ni in R3Ni13-xCoxB2 and the calculated lattice constants are found to agree with reports in literatures. The calculated cohesive energy curves show that Co atoms substitute for Ni with a strong preference for the 3g sites and the order of site preference is 3g, 4h and 6i. Moreover, the total and partial phonon densities of states are first evaluated for the R3Ni13B2 compounds with the hexagonal Nd3Nil3B2-type structure.展开更多
The site preferences of the rare earth intermetallics Nd6Fe13-xTxSi(T = Co, Ni) are investigated by using interatomic pair potentials which are converted from a lattice-inversion method. Calculation shows that the o...The site preferences of the rare earth intermetallics Nd6Fe13-xTxSi(T = Co, Ni) are investigated by using interatomic pair potentials which are converted from a lattice-inversion method. Calculation shows that the order of the site preference of Co is 4d, 16 k, 16l1, and 16l2 and that of Ni is 16l2, 16l1, 16 k, and 4d in Nd6Fe13-xTxSi. Calculated lattice and positional parameters are found to agree with those reported in the literature. Furthermore, the phonon density of states for Nd6Fe13-xTxSiis also evaluated, and a qualitative analysis featuring the coordination and the relevant potentials is carried out.展开更多
We have recently proposed a nanoscale continuum theory for carbon nanotubes.The theory links continuum analysis with atomistic modeling by incor- porating interatomic potentials and atomic structures of carbon nanotub...We have recently proposed a nanoscale continuum theory for carbon nanotubes.The theory links continuum analysis with atomistic modeling by incor- porating interatomic potentials and atomic structures of carbon nanotubes directly into the constitutive law.Here we address two main issues involved in setting up the nanoscale continuum theory for carbon nanotubes,namely the multi-body in- teratomic potentials and the lack of centrosymmetry in the nanotube structure.We explain the key ideas behind these issues in establishing a nanoscale continuum theory in terms of interatomic potentials and atomic structures.展开更多
An Ni-AI-Co system embedded-atom-method potential is constructed for the γ(Ni)/γ'(Ni3A1) superalloy based on experiments and first-principles calculations. The stacking fault energies (SFEs) of the Ni(Co, A1...An Ni-AI-Co system embedded-atom-method potential is constructed for the γ(Ni)/γ'(Ni3A1) superalloy based on experiments and first-principles calculations. The stacking fault energies (SFEs) of the Ni(Co, A1) random solid solutions are calculated as a function of the concentrations of Co and A1. The calculated SFEs decrease with increasing concentrations of Co and A1, which is consistent with the experimental results. The embedding energy term in the present potential has an important influence on the SFEs of the random solid solutions. The cross-slip processes of a screw dislocation in homogenous Ni(Co) solid solutions are simulated using the present potential and the nudged elastic band method. The cross-slip activation energies increase with increasing Co concentration, which implies that the creep resistance of γ(Ni) may be improved by the addition of Co.展开更多
Nanoparticles have been used widely in various fields, and their size and shape greatly affect the functional properties. Therefore, controlling the morphology of the particles is important, and evaluation of the surf...Nanoparticles have been used widely in various fields, and their size and shape greatly affect the functional properties. Therefore, controlling the morphology of the particles is important, and evaluation of the surface energy is indispensable for that purpose. In this study, the surface energy of nanoparticles was evaluated by numerical simulation and formulated in a polynomial equation. First, molecular dynamics simulations were carried out for variously shaped polyhedral nanoparticles. A cube and an octahedron were introduced as reference shapes, and truncated hexahedrons and truncated octahedrons were created by cutting out their vertices. The surface energy was plotted for various polyhedrons. The lowest energy was observed in an octahedron because of the stability of the (111) plane, and the highest energy was observed in a cube because of the relatively higher energy of the (100) plane. Then, the surface energy was formulated in a polynomial equation, in which the parameters obtained by the molecular-dynamics simulations were introduced. As a result, stability of the octahedron and relative instability of the cube were fairly captured by the proposed polynomial equation, while a slight underestimation was inevitable. Finally, the parameters were revised to continuous numbers to extend the application range. Consequently, an application for various materials, such as a cube having equivalent stability to an octahedron, was demonstrated by imposing rather exaggerated parameters.展开更多
INTRODUCTIONIn the deyelopment of material science,it 15 desirable that theand elastic eonstants whieh are the imPoaceurately calculated by means ofrtant meehanical ProPertieseohesive energiesof erystals ean bePhysiea...INTRODUCTIONIn the deyelopment of material science,it 15 desirable that theand elastic eonstants whieh are the imPoaceurately calculated by means ofrtant meehanical ProPertieseohesive energiesof erystals ean bePhysieal meehanies method .展开更多
This paper presents an inverse Monte Carlo method to reconstruct pair interaction potential from pair correlation function. This approach adopts an iterative algorithm on interaction potential to fit known pair correl...This paper presents an inverse Monte Carlo method to reconstruct pair interaction potential from pair correlation function. This approach adopts an iterative algorithm on interaction potential to fit known pair correlation function by compelling deviations of canonical average to meet with Hamiltonian parameters on a basis of statistical mechanism. The effective interaction potential between particles in liquid Ag Rh alloys has been calculated with the inverse Monte Carlo method. It demonstrates an effective and simple way to obtain the effective potential of complex melt systems.展开更多
文摘One of the major tasks in a molecular dynamics (MD) simulation is the selection of adequate potential functions, from which forces are derived. If the potentials do not model the behaviour of the atoms correctly, the results produced from the simulation would be useless. Three popular potentials, namely, Lennard-Jones (L J), Morse, and embedded-atom method (EAM) potentials, were employed to model copper workpiece and diamond tool in nanometric machining. From the simulation results and further analysis, the EAM potential was found to be the most suitable of the three potentials. This is because it best describes the metallic bonding of the copper atoms; it demonstrated the lowest cutting force variation, and the potential energy is most stable for the EAM.
文摘Motivated by the special theory of gradient elasticity (GradEla), a proposal is advanced for extending it to construct gradient models for interatomic potentials, commonly used in atomistic simulations. Our focus is on London’s quantum mechanical potential which is an analytical expression valid until a certain characteristic distance where “attractive” molecular interactions change character and become “repulsive” and cannot be described by the classical form of London’s potential. It turns out that the suggested internal length gradient (ILG) generalization of London’s potential generates both an “attractive” and a “repulsive” branch, and by adjusting the corresponding gradient parameters, the behavior of the empirical Lennard-Jones potentials is theoretically captured.
文摘Al,Ca,and Zn are representative commercial alloying elements for Mg alloys.To investigate the effects of these elements on the deformation and recrystallization behaviors of Mg alloys,we develop interatomic potentials for the Al-Ca,Al-Zn,Mg-Al-Ca and Mg-Al-Zn systems based on the second nearest-neighbor modified embedded-atom method formalism.The developed potentials describe structural,elastic,and thermodynamic properties of compounds and solutions of associated alloy systems in reasonable agreement with experimental data and higher-level calculations.The applicability of these potentials to the present investigation is confirmed by calculating the generalized stacking fault energy for various slip systems and the segregation energy on twin boundaries of the Mg-Al-Ca and Mg-Al-Zn alloys,accompanied with the thermal expansion coefficient and crystal structure maintenance of stable compounds in those alloys.
基金Project supported by the National Basic Research Program of China (Grant No. 2011CB606401)
文摘The lattice-inversion embedded-atom-method interatomic potential developed previously by us is extended to alkaline metals including Li,Na,and K.It is found that considering interatomic interactions between neighboring atoms of an appropriate distance is a matter of great significance in constructing accurate embedded-atom-method interatomic potentials,especially for the prediction of surface energy.The lattice-inversion embedded-atom-method interatomic potentials for Li,Na,and K are successfully constructed by taking the fourth-neighbor atoms into consideration.These angular-independent potentials markedly promote the accuracy of predicted surface energies,which agree well with experimental results.In addition,the predicted structural stability,elastic constants,formation and migration energies of vacancy,and activation energy of vacancy diffusion are in good agreement with available experimental data and first-principles calculations,and the equilibrium condition is satisfied.
基金Supported by the National Natural Science Foundation of China(No.2 9892 16 6 ,2 980 30 0 6 ,2 99830 0 1)
文摘We applied an approach to the development of many-body interatomic potentials for NiZr alloys,gaining an improved accuracy and reliability.The functional form of the potential is that of the embedded method,but it has been improved as follows. (1) The database used for the development of the potential includes both experimental data and a large set of energies of different structures of the alloys generated by Fab initio calculations. (2) The optimum parametrization of the potential for the given database is obtained by fitting. Using this approach we developed reliable interatomic potentials for Ni and Zr. The potential accurately reproduces basic equilibrium properties of the alloys.
基金supported by the National Natural Science Foundation of China (Grant No. 52173234)the Shenzhen Science and Technology Program (Grant Nos. JCYJ20210324102008023 and JSGG202108021534-08024)+3 种基金the Shenzhen-Hong Kong-Macao Technology Research Program(Type C, SGDX2020110309300301)the Natural Science Foundation of Guangdong Province (Grant No. 2022A1515010554)CCF-Tencent Open FundNingbo Municipal Key Laboratory on Clean Energy Conversion Technologies and the Zhejiang Provincial Key Laboratory for Carbonaceous Wastes Processing and Process Intensification Research funded by the Zhejiang Provincial Department of Science and Technology (Grant No. 2020E10018)
文摘Carbon neutrality has been proposed as a solution for the current severe energy and climate crisis caused by the overuse of fossil fuels, and machine learning(ML) has exhibited excellent performance in accelerating related research owing to its powerful capacity for big data processing. This review presents a detailed overview of ML accelerated carbon neutrality research with a focus on energy management, screening of novel energy materials, and ML interatomic potentials(MLIPs), with illustrations of two selected MLIP algorithms: moment tensor potential(MTP) and neural equivariant interatomic potential(NequIP). We conclude by outlining the important role of ML in accelerating the achievement of carbon neutrality from global-scale energy management, unprecedented screening of advanced energy materials in massive chemical space, to the revolution of atomicscale simulations of MLIPs, which has the bright prospect of applications.
基金This work was financially supported by the National MCF Energy R&D Program of China(Grant No.2018YFE0308101)the National Key R&D Program of China(Grant No.2018YFB0704002)the National Natural Science Foundation of China(Grant Nos.51771073,11975260).
文摘The structure and properties of materials under neutron irradiation are an important basis in future fusion reactors.In the absence of fusion neutron sources for irradiation experiments,it is increasingly important and urgent to carry out neutron irradiation simulations on fusion reactor materials and then establish complete databases of defect properties and collisional cascades,where the first and foremost step is to select suitable interatomic potentials for atomistic-level simulations.In this work,six typic interatomic potentials for tungsten(W)are evaluated and reviewed systematically for radiation damage simulations.The relative lattice stability and elastic constants of bulk W are considered first with those potentials;then,the properties of point defects and defect clusters at interstitial sites and vacancies are obtained by molecular statics/dynam-ics simulations.The formation energies of interstitial/vacancy clusters,1/2<111>and<100>dislocation loops in W and the threshold displacement energies along different directions are also determined.In addition,the extended defects are further investigated,such as free surfaces and the energy profiles of 1/2<111>{110}and 1/2<111>{112}stacking faults.The current results provide a reference for selecting W potentials to simulate the radiation damage.
文摘In this paper, we deduce the analytical form of many-body interatomic potentials based on the Green's function in tight-binding representation. The many-body potentials are expressed as the functions of the hopping integrals which are the physical origin of cohesion of atoms. For thesimple case of s-valent system, the inversion of the many-body potentials are discussed in detail by using the lattice inversion method.
基金This study was supported by the Wuhan University Junior Faculty Research(2042019KF0003)the National Natural Science Foundation of China(51727901,U1501241,and 62174122)+1 种基金the National Key R&D Program of China(2017YFB1103904)the Hubei Provincial Natural Science Foundation of China(2020CFA032).
文摘This paper summarizes the progress of machine-learning-based interatomic potentials and their applications in advanced manufacturing.Interatomic potential is essential for classical molecular dynamics.The advancements made in machine learning(ML)have enabled the development of fast interatomic potential with ab initio accuracy.The accelerated atomic simulation can greatly transform the design principle of manufacturing technology.The most widely used supervised and unsupervised ML methods are summarized and compared.Then,the emerging interatomic models based on ML are discussed:Gaussian approximation potential,spectral neighbor analysis potential,deep potential molecular dynamics,SCHNET,hierarchically interacting particle neural network,and fast learning of atomistic rare events.
基金Scientific and Technological Research of Chongqing Municipal Education Commission(Grant No.KJZD-K202100602)the funding of Institute for Advanced Sciences of Chongqing University of Posts and Telecommunications(Grant No.E011A2022326)。
文摘The investigation of thermal transport is crucial to the thermal management of modern electronic devices.To obtain the thermal conductivity through solution of the Boltzmann transport equation,calculation of the anharmonic interatomic force constants has a high computational cost based on the current method of single-point density functional theory force calculation.The recent suggested machine learning interatomic potentials(MLIPs)method can avoid these huge computational demands.In this work,we study the thermal conductivity of two-dimensional MoS_(2)-like hexagonal boron dichalcogenides(H-B_(2)VI_(2);V I=S,Se,Te)with a combination of MLIPs and the phonon Boltzmann transport equation.The room-temperature thermal conductivity of H-B_(2)S_(2)can reach up to 336 W·m^(-1)·K^(-1),obviously larger than that of H-B_(2)Se_(2)and H-B_(2)Te_(2).This is mainly due to the difference in phonon group velocity.By substituting the different chalcogen elements in the second sublayer,H-B_(2)VIV I′have lower thermal conductivity than H-B_(2)VI_(2).The room-temperature thermal conductivity of B2STe is only 11%of that of H-B_(2)S_(2).This can be explained by comparing phonon group velocity and phonon relaxation time.The MLIP method is proved to be an efficient method for studying the thermal conductivity of materials,and H-B_(2)S_(2)-based nanodevices have excellent thermal conduction.
基金the National Key Research and Development Program of China(Grant No.2017YFB0702401)the National Natural Science Foundation of China(Grant No.51631005).
文摘To shed a light on Xe bubble nucleation in U–Mo fuel from the view of primary irradiation damage,a reported U–Mo–Xe potential under the framework of embedded atom method has been modified within the range of short and intermediate atomic distance.The modified potential can better describe the interactions between energetic particles,and can accurately reproduce the threshold displacement energy surface calculated by the first-principles method.Then,molecular dynamics simulations of primary irradiation damage in U–Mo–Xe system have been conducted under different contents.The raise of Xe concentration brings about a remarkable promotion in residual defect quantity and generates bubbles in more overpressured state,which suggests an acceleration of irradiation damage under the accumulation of the fission gas.Meanwhile,the addition of Mo considerably reduces the residual defect count and hinders irradiation-induced Xe diffusion especially at high contents of Xe,corroborating the importance of high Mo content in mitigation of irradiation damage and swelling behavior in U–Mo fuel.In particular,the variation of irradiation damage with respect to contents suggests a necessity of taking into account the influence of local components on defect evolution in mesoscale simulations.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFE03110000)the National Natural Science Foundation of China(Nos.52171084 and 12192282)the Foundation of President of Hefei Institutes of Physical Science,Chinese Academy of Sciences(Nos.YZJJQY202203 and BJPY2021A05).
文摘So far, it has been a challenge for existing interatomic potentials to accurately describe a wide range of physical properties and maintain reasonable efficiency. In this work, we develop an interatomic potential for simulating radiation damage in body-centered cubic tungsten by employing deep potential, a neural network-based deep learning model for representing the potential energy surface. The resulting potential predicts a variety of physical properties consistent with first-principles calculations, including phonon spectrum, thermal expansion, generalized stacking fault energies, energetics of free surfaces, point defects, vacancy clusters, and prismatic dislocation loops. Specifically, we investigated the elasticity-related properties of prismatic dislocation loops, i.e., their dipole tensors, relaxation volumes, and elastic interaction energies. This potential is found to predict the maximal elastic interaction energy between two 1/2 <1 1 1> loops better than previous potentials, with a relative error of only 7.6%. The predicted threshold displacement energies are in reasonable agreement with experimental results, with an average of 128 eV. The efficiency of the present potential is also comparable to the tabulated gaussian approximation potentials and modified embedded atom method potentials, meanwhile, can be further accelerated by graphical processing units. Extensive benchmark tests indicate that this potential has a relatively good balance between accuracy, transferability, and efficiency.
基金Project supported by the National Natural Science Foundation of China (Grant No.50971024)
文摘The effects of Fe substitution for Co on the structural stability and the site preference of intermetallics Nd2CoT-xFex with a hexagonal Ce2NiT-type structure are studied by using a series of interatomic pair potentials. In Nd2CoT-xFex, Fe atoms are substituted for Co atoms with a strong preference for the 6h sites and the order of site preference is 6h, 4e, 4f, 2a, and 12k. Calculated lattice parameters are found to be consistent with the reported results in the literature. The variation behaviour of the Curie temperature of Nd2CoT-xFex is explained qualitatively by the exchange interaction model. The properties related to lattice vibration, such as phonon density of states and Debye temperature, are first evaluated for the Nd2Co7 xFex compounds.
基金Project supported by the National Basic Research Program of China (Grant No. 2006CB605101)the National Natural Science Foundation of China (Grant No. 50971024)
文摘This paper investigates the structural stability of intermetallics R3Ni13-xCoxB2 (R=Y, Nd and Sm) with Nd3Ni13B2-type structure and the site preferences of the transition element Co by using a series of interatomic pair potentials. The space group remains unchanged upon substitution of Co for Ni in R3Ni13-xCoxB2 and the calculated lattice constants are found to agree with reports in literatures. The calculated cohesive energy curves show that Co atoms substitute for Ni with a strong preference for the 3g sites and the order of site preference is 3g, 4h and 6i. Moreover, the total and partial phonon densities of states are first evaluated for the R3Ni13B2 compounds with the hexagonal Nd3Nil3B2-type structure.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11272048 and 50971024)the National Key Basic Research Program of China(Grant No.2011CB606401)
文摘The site preferences of the rare earth intermetallics Nd6Fe13-xTxSi(T = Co, Ni) are investigated by using interatomic pair potentials which are converted from a lattice-inversion method. Calculation shows that the order of the site preference of Co is 4d, 16 k, 16l1, and 16l2 and that of Ni is 16l2, 16l1, 16 k, and 4d in Nd6Fe13-xTxSi. Calculated lattice and positional parameters are found to agree with those reported in the literature. Furthermore, the phonon density of states for Nd6Fe13-xTxSiis also evaluated, and a qualitative analysis featuring the coordination and the relevant potentials is carried out.
文摘We have recently proposed a nanoscale continuum theory for carbon nanotubes.The theory links continuum analysis with atomistic modeling by incor- porating interatomic potentials and atomic structures of carbon nanotubes directly into the constitutive law.Here we address two main issues involved in setting up the nanoscale continuum theory for carbon nanotubes,namely the multi-body in- teratomic potentials and the lack of centrosymmetry in the nanotube structure.We explain the key ideas behind these issues in establishing a nanoscale continuum theory in terms of interatomic potentials and atomic structures.
基金Project supported by the National Basic Research Program of China(Grant No.2011CB606402)the National Natural Science Foundation of China(Grant No.51071091)
文摘An Ni-AI-Co system embedded-atom-method potential is constructed for the γ(Ni)/γ'(Ni3A1) superalloy based on experiments and first-principles calculations. The stacking fault energies (SFEs) of the Ni(Co, A1) random solid solutions are calculated as a function of the concentrations of Co and A1. The calculated SFEs decrease with increasing concentrations of Co and A1, which is consistent with the experimental results. The embedding energy term in the present potential has an important influence on the SFEs of the random solid solutions. The cross-slip processes of a screw dislocation in homogenous Ni(Co) solid solutions are simulated using the present potential and the nudged elastic band method. The cross-slip activation energies increase with increasing Co concentration, which implies that the creep resistance of γ(Ni) may be improved by the addition of Co.
文摘Nanoparticles have been used widely in various fields, and their size and shape greatly affect the functional properties. Therefore, controlling the morphology of the particles is important, and evaluation of the surface energy is indispensable for that purpose. In this study, the surface energy of nanoparticles was evaluated by numerical simulation and formulated in a polynomial equation. First, molecular dynamics simulations were carried out for variously shaped polyhedral nanoparticles. A cube and an octahedron were introduced as reference shapes, and truncated hexahedrons and truncated octahedrons were created by cutting out their vertices. The surface energy was plotted for various polyhedrons. The lowest energy was observed in an octahedron because of the stability of the (111) plane, and the highest energy was observed in a cube because of the relatively higher energy of the (100) plane. Then, the surface energy was formulated in a polynomial equation, in which the parameters obtained by the molecular-dynamics simulations were introduced. As a result, stability of the octahedron and relative instability of the cube were fairly captured by the proposed polynomial equation, while a slight underestimation was inevitable. Finally, the parameters were revised to continuous numbers to extend the application range. Consequently, an application for various materials, such as a cube having equivalent stability to an octahedron, was demonstrated by imposing rather exaggerated parameters.
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基金Project supported partially by National Natural Science Foundation of China (Grant Nos 50831003 and 50871062)the National Basic Research Program of China (Grant No 2007CB613901)+1 种基金Natural Science Fund for Distinguished Young Scholars of Shandong Province (Grant No JQ200817)National Science Fund for Distinguished Young Scholars (Grant No 50625101)
文摘This paper presents an inverse Monte Carlo method to reconstruct pair interaction potential from pair correlation function. This approach adopts an iterative algorithm on interaction potential to fit known pair correlation function by compelling deviations of canonical average to meet with Hamiltonian parameters on a basis of statistical mechanism. The effective interaction potential between particles in liquid Ag Rh alloys has been calculated with the inverse Monte Carlo method. It demonstrates an effective and simple way to obtain the effective potential of complex melt systems.