Alexander Sivak - Academia.edu (original) (raw)
Papers by Alexander Sivak
Symmetry, 2021
The effect of external and internal elastic strain fields on the anisotropic diffusion of radiati... more The effect of external and internal elastic strain fields on the anisotropic diffusion of radiation defects (RDs) can be taken into account if one knows the dipole tensor of saddle-point configurations of the diffusing RDs. It is usually calculated by molecular statics, since the insufficient accuracy of the available experimental techniques makes determining it experimentally difficult. However, for an RD with multiple crystallographically non-equivalent metastable and saddle-point configurations (as in the case of di-interstitials), the problem becomes practically unsolvable due to its complexity. In this paper, we used a different approach to solving this problem. The molecular dynamics (MD) method was used to calculate the strain dependences of the RD diffusion tensor for various types of strain states. These dependences were used to determine the dipole tensor of the effective RD saddle-point configuration, which takes into account the contributions of all real saddle-point con...
In bcc V and Fe crystals, the study of formation and migration mechanisms, energetic and crystall... more In bcc V and Fe crystals, the study of formation and migration mechanisms, energetic and crystallographic characteristics of self-point defects (self interstitial atom, vacancy) has been carried out by molecular statics and molecular dynamics methods with use of semiempirical many body interaction potentials.
AIP Conference Proceedings
The formation energy, the relaxation volume, the dipole-force tensor, the self strain tensor and ... more The formation energy, the relaxation volume, the dipole-force tensor, the self strain tensor and strain fields of interstitial dislocation loops in bcc iron (clusters of self interstitial atoms) have been calculated by molecular statics. Hexagonal and square dislocation loops of different types with different Burgers vectors, directions of dislocation segments and habit planes containing up to ~2500 self-interstitials have been considered. Analytical expressions describing size dependence of the formation energy, the relaxation volume and the self strain tensor for the loops stated have been obtained. The most energetically favorable loops are hexagonal loops with Burgers vector a/2<111> and habit plane {11x}, where x takes values in the range from 0 to 1 depending on the loop size. The formation energy of a<100> loops with <100> and <110> dislocation segments is ~14% and 23% greater than that of hexagonal a/2<111> loops at N > 500, respectively. The analysis of the formation energies of a/2<111> and a<100> loops demonstrated that the nucleation of an a<100> loop by joining of two a/2<111> loops is possible when the total number of constituent self-interstitials in these loops is larger than 13.
Spatial dependence of the elastic interaction energy between the self-point defects and the strai... more Spatial dependence of the elastic interaction energy between the self-point defects and the straight edge (<110>{111} and <110>{110}) and screw (Burgers vector ½ <110>) dislocations in FCC Pu was calculated by hybrid method. Elastic fields of dislocations and their interactions with point defects (elastic dipoles) were calculated in the framework of the anisotropic theory of elasticity. Characteristics of point defects (formation and migration energies, relaxation volumes and dipole moment tensors) in the absence of dislocation stress fields were calculated by molecular statics method (MEAM-type interaction potential).
Inorganic Materials: Applied Research
The efficiency of linear sinks for self point defects (SPDs) elastically interacting (dislocation... more The efficiency of linear sinks for self point defects (SPDs) elastically interacting (dislocations) and not interacting with sinks with the density of 3 × 10 14 m-2 is calculated for BCC (Fe, V) and FCC (Cu) crystals at the temperature 293 K using the object kinetic Monte Carlo technique, depending on type and value of applied mechanical load (up to 200 MPa) and types of linear sinks. Full straight dislocations in slip systems [111](1 0), [111](11), [100](001), and [100](011) for Fe and V and [100](001) for Cu are considered for dislocation sinks (DSs). Orientations of noninteracting linear sinks (NILSs) coincide with those of DSs. Interaction of SPDs with internal (dislocation) and external stress fields is calculated within the framework of anisotropic linear theory of elasticity. Relative changes in efficiency of different co directional linear sinks (either interacting or not interacting with SPDs) under action of applied stress are approximately identical under low stress. Radiation creep rates are calculated for the considered crystals under uniaxial stress in the stationary regime of Frenkel pairs generation. The creep rate strongly depends on the loading direction and Burgers vector of dislocations in Fe and V, and it is almost independent of these parameters in Cu. At the same generation rate of Frenkel pairs, the radiation creep rate averaged over all loading directions is significantly higher in BCC (Fe, V) crystals containing dislocations with the Burgers vector a/2〈111〉 than in FCC (Cu) crystals.
Поля напряжений дислокационных скоплений (границ разных типов) оказывают значительное влияние на ... more Поля напряжений дислокационных скоплений (границ разных типов) оказывают значительное влияние на образование и кинетику собственных точечных дефектов (СТД: вакансий и межузельных атомов), определяя особенности образования и распада твёрдых растворов СТД. В связи с этим представляется важным исследовать влияние полей напряжений от дислокационных скоплений (границ) на энергетику образования и миграции СТД в кристаллах с разными степенями упругой анизотропии. В рамках анизотропной теории упругости рассчитана пространственная зависимость энергии взаимодействия СТД с малоугловыми границами наклона (бесконечные дислокационные стенки, состоящие из краевых дислокаций в системах скольжения <111>{110} и <111>{112}) в ОЦК-кристаллах железа и ванадия. Определены расстояния до малоугловых границ, на которых это взаимодействие существенно влияет на поведение СТД, в зависимости от температуры и угла разориентировки границ. При однородной генерации СТД по всему объёму кристалла их потоки слева и справа на малоугловую границу наклона могут быть разными. Ключевые слова: железо, ванадий, дислокационные стенки, малоугловые границы, поля напряжений, вакансии, собственные межузельные атомы, анизотропная теория упругости, взаимодействие, энергия образования и миграция собственных точечных дефектов.
Модифицирован многочастичный потенциал для водорода в объёмно-центрированном кубическом железе (О... more Модифицирован многочастичный потенциал для водорода в объёмно-центрированном кубическом железе (ОЦК-железе), разработанный A. Рамасубраманиамом и др., для использования в матрице ОЦК-железа, взаимодействия в которой описываются многочастичным потенциалом, разработанным Л. Малерба и др. Рассчитаны энергетические и кристаллографические характеристики различных конфигураций межузельного водорода и его комплексов с собственными точечными дефектами (вакансия, собственный межузельный атом) и краевой дислокацией с вектором Бюргерса <100> методом молекулярной статики с использованием предложенного модифицированного потенциала межатомного взаимодействия. Полученные результаты согласуются с характеристиками водорода в железе, известными из эксперимента и расчётов в рамках теории функционала электронной плотности. Ключевые слова: ОЦК-кристалл железа, водород, потенциалы межатомного взаимодействия, молекулярная статика, собственные точечные дефекты, кристаллографические и энергетические характеристики, краевая дислокация.
In hcp Zr crystal, stable and metastable (including saddle point) configurations of self-point de... more In hcp Zr crystal, stable and metastable (including saddle point) configurations of self-point defects (SIA – self-intersitial atoms, vacancies) were found. Formation and migration energies, relaxation volumes and dipole tensors of these configurations were calculated by computer simulation methods with use the interaction potential developed in the framework of Finnis-Sinclair method. The stress fields of the straight edge dislocation <11-20>{0001} and spatial dependence of the interaction energy between these fields and self-point defects (SPD) were calculated in the frameworks of the anisotropic theory of elasticity. The dislocation stress fields significantly affect the point defects characteristics and behavior in hcp Zr.
Vanadium and its heat-resistant low-activation alloys are advanced structural materials for fusio... more Vanadium and its heat-resistant low-activation alloys are advanced structural materials for fusion and fission reactors. Development of such alloys is restrained by lack of knowledge of mechanisms and characteristics of formation and evolution of self-point defects (SPD): vacancies , self-interstitial atoms (SIA), their clusters. There are alternate models predicting different values of SPDs characteristics in pure vanadi-um, and, as a consequence, different microstructure behaviour under irradiation. In this study, equilibrium characteristics of different SPDs configurations and temperature dependences of diffusivities in temperature ranges 1200—2200 K for vacancy and 300—2000 K for SIA have been obtained using computer simulations based on the developed semiempirical interatomic interaction potential in vanadium. Comparison of theoretical results with experimental data has been performed. The most preferred conceptual model of vanadium crystal based on the underlying basic SPDs ch...
The effect of dislocations stress fields on their sinks efficiencies for hydrogen interstitial at... more The effect of dislocations stress fields on their sinks efficiencies for hydrogen interstitial atoms has been studied for temperatures 293 and 600 K and dislocation density 3x10 14 m –2 in BCC iron crystal. Straight full screw and edge dislocations in basic slip systems <111>{110}, <111>{112}, <100>{100}, <100>{110} have been considered. Diffusion of defects has been simulated by object kinetic Monte Carlo method. Interaction energies of defects with dislocations have been calculated within the anisotropic theory of elasticity. Elastic fields of dislocations change the sink efficiency of not more than 25% of the non-interacting linear sink efficiency at room temperature. Elastic fields of edge dislocations increase the dislocations sink efficiency, and the elastic fields of screw ones either decrease (in the case of dislocations with ½ <111> Burgers vector), or do not change (in the case of dislocations with <100> Burgers vector). At temperatures ...
Inorganic Materials: Applied Research, 2015
ABSTRACT The effect of the dislocations stress fields on their sink efficiency for self-point def... more ABSTRACT The effect of the dislocations stress fields on their sink efficiency for self-point defects (interstitial atoms and vacancies) is studied in the temperature range of 293–1000 K and at the dislocation density values of 1 × 1012–3 × 1014 m–2 in body-centered cubic (BCC) iron and vanadium crystals. Straight screw and edge dislocations in 〈111〉{110}, 〈111〉{112}, 〈100〉{100}, and 〈100〉{110} slip systems are considered. Defect diffusion is simulated via the object kinetic Monte Carlo method. The energies of the interaction of defects with dislocations are calculated within the anisotropic linear theory of elasticity. The dislocation sink efficiency is analytically represented as a function of temperature and dislocation density.
Journal of Nuclear Materials, 2015
ABSTRACT Energetic, crystallographic and diffusion characteristics of various interstitial config... more ABSTRACT Energetic, crystallographic and diffusion characteristics of various interstitial configurations of H atoms and their complexes with self-point defects (SIA – self-interstitial atom, V – vacancy) in bcc iron have been calculated by molecular statics and molecular dynamics using Fe–H interatomic interaction potential developed by Ramasubramaniam et al. (2009) and modified by the authors of the present work and Fe–Fe matrix potential M07 developed by Malerba et al. (2010). The most energetically favorable configuration of an interstitial H atom is tetrahedral configuration. The energy barrier for H atom migration is 0.04 eV. The highest binding energy of all the considered complexes “vacancy – H atom” and “SIA – H atom” is 0.54 and 0.15 eV, respectively. The binding energy of H atom with edge dislocations in slip systems 〈1 1 1〉{1 1 0}, 〈1 1 1〉{1 1 2}, 〈1 0 0〉{1 0 0}, 〈1 0 0〉{1 1 0} is 0.32, 0.30, 0.45, 0.54 eV, respectively. The binding energy of H atom in VHn complexes (n = 1 … 15) decreases from 0.54 to 0.35 eV with increasing of n from 1 to 6. At n > 6, it decreases to ∼0.1 eV. The temperature dependences of hydrogen isotopes (P, D, T) diffusivities have been calculated for the temperature range 70–1800 K. Arrhenius-type dependencies describe the calculated data at temperatures T < 100 K. At T > 250 K, the temperature dependencies of the diffusivities DP, DD, DT have a parabolic form. The diffusivities of H isotopes are within 10% at room temperature. The isotope effect becomes stronger at higher temperatures, e.g., ratios DP/DD and DP/DT at 1800 K equal 1.23 and 1.40, respectively.
Crystallography Reports, 2014
The sink efficiency of perfect dislocations for self point defects (interstitials and vacancies) ... more The sink efficiency of perfect dislocations for self point defects (interstitials and vacancies) in fcc copper crystal has been calculated by the kinetic Monte Carlo method in a temperature range of 293-1000 K and a range of dislocation densities from 1.3 × 10 12 to 3.0 × 10 14 m-2. Screw, mixed, and edge dislocations with a Burgers vector 1/2〈110〉 in different slip systems are analyzed. The interaction energies of self point defects with dislocations are calculated using the anisotropic theory of elasticity. Analytical expressions are proposed for the dependences of the calculated values of dislocation sink efficiency on temperature and dis location density.
Journal of Nuclear Materials, 2003
ABSTRACT
Crystallography Reports, 2010
The energetic, crystallographic, and diffusion characteristics of self point defects (SPDs) (vaca... more The energetic, crystallographic, and diffusion characteristics of self point defects (SPDs) (vacan cies and self interstitial atoms (SIAs)) in body centered cubic (bcc) iron crystal in the absence of stress fields have been obtained by the molecular statics and molecular dynamics methods. The effect of elastic stress fields of dislocations on the characteristics of SPDs (elastic dipoles) has been calculated by the methods of the anisotropic linear theory of elasticity. The SPD diffusion in the elastic fields of edge and screw dislocations (with Burgers vectors 1/2 〈111〉 and 〈100〉) at 293 K has been studied by the kinetic Monte Carlo method. The values of the SPD sink strength of dislocations of different types are obtained. Dislocations are more effective sinks for SIAs than for vacancies. The difference in the sink strengths for SIAs and vacancies in the case of edge dislocations is larger than the screw dislocations.
Crystallography Reports, 2010
The crystallographic, energetic, and kinetic characteristics of intrinsic point defects (vacancys... more The crystallographic, energetic, and kinetic characteristics of intrinsic point defects (vacancyself interstitial atom) in stable, metastable, and saddle configurations in hcp zirconium crystal have been cal culated by the molecular statics method. The spatial dependences of the interaction energies of intrinsic point defects and stress fields of rectilinear dislocations with Burgers vectors of 1/3[11 0], 1/3 [11 3], and [0001] have been found within the anisotropic linear theory of elasticity. The most likely trajectories of intrin sic point defects in dislocation stress fields (trajectories with minimum energy barriers for motion) have been constructed. Such trajectories result in dislocation only for the interaction of self interstitial atoms with an edge dislocation that has a Burgers vector of 1/3 [11 3].
Symmetry, 2021
The effect of external and internal elastic strain fields on the anisotropic diffusion of radiati... more The effect of external and internal elastic strain fields on the anisotropic diffusion of radiation defects (RDs) can be taken into account if one knows the dipole tensor of saddle-point configurations of the diffusing RDs. It is usually calculated by molecular statics, since the insufficient accuracy of the available experimental techniques makes determining it experimentally difficult. However, for an RD with multiple crystallographically non-equivalent metastable and saddle-point configurations (as in the case of di-interstitials), the problem becomes practically unsolvable due to its complexity. In this paper, we used a different approach to solving this problem. The molecular dynamics (MD) method was used to calculate the strain dependences of the RD diffusion tensor for various types of strain states. These dependences were used to determine the dipole tensor of the effective RD saddle-point configuration, which takes into account the contributions of all real saddle-point con...
In bcc V and Fe crystals, the study of formation and migration mechanisms, energetic and crystall... more In bcc V and Fe crystals, the study of formation and migration mechanisms, energetic and crystallographic characteristics of self-point defects (self interstitial atom, vacancy) has been carried out by molecular statics and molecular dynamics methods with use of semiempirical many body interaction potentials.
AIP Conference Proceedings
The formation energy, the relaxation volume, the dipole-force tensor, the self strain tensor and ... more The formation energy, the relaxation volume, the dipole-force tensor, the self strain tensor and strain fields of interstitial dislocation loops in bcc iron (clusters of self interstitial atoms) have been calculated by molecular statics. Hexagonal and square dislocation loops of different types with different Burgers vectors, directions of dislocation segments and habit planes containing up to ~2500 self-interstitials have been considered. Analytical expressions describing size dependence of the formation energy, the relaxation volume and the self strain tensor for the loops stated have been obtained. The most energetically favorable loops are hexagonal loops with Burgers vector a/2<111> and habit plane {11x}, where x takes values in the range from 0 to 1 depending on the loop size. The formation energy of a<100> loops with <100> and <110> dislocation segments is ~14% and 23% greater than that of hexagonal a/2<111> loops at N > 500, respectively. The analysis of the formation energies of a/2<111> and a<100> loops demonstrated that the nucleation of an a<100> loop by joining of two a/2<111> loops is possible when the total number of constituent self-interstitials in these loops is larger than 13.
Spatial dependence of the elastic interaction energy between the self-point defects and the strai... more Spatial dependence of the elastic interaction energy between the self-point defects and the straight edge (<110>{111} and <110>{110}) and screw (Burgers vector ½ <110>) dislocations in FCC Pu was calculated by hybrid method. Elastic fields of dislocations and their interactions with point defects (elastic dipoles) were calculated in the framework of the anisotropic theory of elasticity. Characteristics of point defects (formation and migration energies, relaxation volumes and dipole moment tensors) in the absence of dislocation stress fields were calculated by molecular statics method (MEAM-type interaction potential).
Inorganic Materials: Applied Research
The efficiency of linear sinks for self point defects (SPDs) elastically interacting (dislocation... more The efficiency of linear sinks for self point defects (SPDs) elastically interacting (dislocations) and not interacting with sinks with the density of 3 × 10 14 m-2 is calculated for BCC (Fe, V) and FCC (Cu) crystals at the temperature 293 K using the object kinetic Monte Carlo technique, depending on type and value of applied mechanical load (up to 200 MPa) and types of linear sinks. Full straight dislocations in slip systems [111](1 0), [111](11), [100](001), and [100](011) for Fe and V and [100](001) for Cu are considered for dislocation sinks (DSs). Orientations of noninteracting linear sinks (NILSs) coincide with those of DSs. Interaction of SPDs with internal (dislocation) and external stress fields is calculated within the framework of anisotropic linear theory of elasticity. Relative changes in efficiency of different co directional linear sinks (either interacting or not interacting with SPDs) under action of applied stress are approximately identical under low stress. Radiation creep rates are calculated for the considered crystals under uniaxial stress in the stationary regime of Frenkel pairs generation. The creep rate strongly depends on the loading direction and Burgers vector of dislocations in Fe and V, and it is almost independent of these parameters in Cu. At the same generation rate of Frenkel pairs, the radiation creep rate averaged over all loading directions is significantly higher in BCC (Fe, V) crystals containing dislocations with the Burgers vector a/2〈111〉 than in FCC (Cu) crystals.
Поля напряжений дислокационных скоплений (границ разных типов) оказывают значительное влияние на ... more Поля напряжений дислокационных скоплений (границ разных типов) оказывают значительное влияние на образование и кинетику собственных точечных дефектов (СТД: вакансий и межузельных атомов), определяя особенности образования и распада твёрдых растворов СТД. В связи с этим представляется важным исследовать влияние полей напряжений от дислокационных скоплений (границ) на энергетику образования и миграции СТД в кристаллах с разными степенями упругой анизотропии. В рамках анизотропной теории упругости рассчитана пространственная зависимость энергии взаимодействия СТД с малоугловыми границами наклона (бесконечные дислокационные стенки, состоящие из краевых дислокаций в системах скольжения <111>{110} и <111>{112}) в ОЦК-кристаллах железа и ванадия. Определены расстояния до малоугловых границ, на которых это взаимодействие существенно влияет на поведение СТД, в зависимости от температуры и угла разориентировки границ. При однородной генерации СТД по всему объёму кристалла их потоки слева и справа на малоугловую границу наклона могут быть разными. Ключевые слова: железо, ванадий, дислокационные стенки, малоугловые границы, поля напряжений, вакансии, собственные межузельные атомы, анизотропная теория упругости, взаимодействие, энергия образования и миграция собственных точечных дефектов.
Модифицирован многочастичный потенциал для водорода в объёмно-центрированном кубическом железе (О... more Модифицирован многочастичный потенциал для водорода в объёмно-центрированном кубическом железе (ОЦК-железе), разработанный A. Рамасубраманиамом и др., для использования в матрице ОЦК-железа, взаимодействия в которой описываются многочастичным потенциалом, разработанным Л. Малерба и др. Рассчитаны энергетические и кристаллографические характеристики различных конфигураций межузельного водорода и его комплексов с собственными точечными дефектами (вакансия, собственный межузельный атом) и краевой дислокацией с вектором Бюргерса <100> методом молекулярной статики с использованием предложенного модифицированного потенциала межатомного взаимодействия. Полученные результаты согласуются с характеристиками водорода в железе, известными из эксперимента и расчётов в рамках теории функционала электронной плотности. Ключевые слова: ОЦК-кристалл железа, водород, потенциалы межатомного взаимодействия, молекулярная статика, собственные точечные дефекты, кристаллографические и энергетические характеристики, краевая дислокация.
In hcp Zr crystal, stable and metastable (including saddle point) configurations of self-point de... more In hcp Zr crystal, stable and metastable (including saddle point) configurations of self-point defects (SIA – self-intersitial atoms, vacancies) were found. Formation and migration energies, relaxation volumes and dipole tensors of these configurations were calculated by computer simulation methods with use the interaction potential developed in the framework of Finnis-Sinclair method. The stress fields of the straight edge dislocation <11-20>{0001} and spatial dependence of the interaction energy between these fields and self-point defects (SPD) were calculated in the frameworks of the anisotropic theory of elasticity. The dislocation stress fields significantly affect the point defects characteristics and behavior in hcp Zr.
Vanadium and its heat-resistant low-activation alloys are advanced structural materials for fusio... more Vanadium and its heat-resistant low-activation alloys are advanced structural materials for fusion and fission reactors. Development of such alloys is restrained by lack of knowledge of mechanisms and characteristics of formation and evolution of self-point defects (SPD): vacancies , self-interstitial atoms (SIA), their clusters. There are alternate models predicting different values of SPDs characteristics in pure vanadi-um, and, as a consequence, different microstructure behaviour under irradiation. In this study, equilibrium characteristics of different SPDs configurations and temperature dependences of diffusivities in temperature ranges 1200—2200 K for vacancy and 300—2000 K for SIA have been obtained using computer simulations based on the developed semiempirical interatomic interaction potential in vanadium. Comparison of theoretical results with experimental data has been performed. The most preferred conceptual model of vanadium crystal based on the underlying basic SPDs ch...
The effect of dislocations stress fields on their sinks efficiencies for hydrogen interstitial at... more The effect of dislocations stress fields on their sinks efficiencies for hydrogen interstitial atoms has been studied for temperatures 293 and 600 K and dislocation density 3x10 14 m –2 in BCC iron crystal. Straight full screw and edge dislocations in basic slip systems <111>{110}, <111>{112}, <100>{100}, <100>{110} have been considered. Diffusion of defects has been simulated by object kinetic Monte Carlo method. Interaction energies of defects with dislocations have been calculated within the anisotropic theory of elasticity. Elastic fields of dislocations change the sink efficiency of not more than 25% of the non-interacting linear sink efficiency at room temperature. Elastic fields of edge dislocations increase the dislocations sink efficiency, and the elastic fields of screw ones either decrease (in the case of dislocations with ½ <111> Burgers vector), or do not change (in the case of dislocations with <100> Burgers vector). At temperatures ...
Inorganic Materials: Applied Research, 2015
ABSTRACT The effect of the dislocations stress fields on their sink efficiency for self-point def... more ABSTRACT The effect of the dislocations stress fields on their sink efficiency for self-point defects (interstitial atoms and vacancies) is studied in the temperature range of 293–1000 K and at the dislocation density values of 1 × 1012–3 × 1014 m–2 in body-centered cubic (BCC) iron and vanadium crystals. Straight screw and edge dislocations in 〈111〉{110}, 〈111〉{112}, 〈100〉{100}, and 〈100〉{110} slip systems are considered. Defect diffusion is simulated via the object kinetic Monte Carlo method. The energies of the interaction of defects with dislocations are calculated within the anisotropic linear theory of elasticity. The dislocation sink efficiency is analytically represented as a function of temperature and dislocation density.
Journal of Nuclear Materials, 2015
ABSTRACT Energetic, crystallographic and diffusion characteristics of various interstitial config... more ABSTRACT Energetic, crystallographic and diffusion characteristics of various interstitial configurations of H atoms and their complexes with self-point defects (SIA – self-interstitial atom, V – vacancy) in bcc iron have been calculated by molecular statics and molecular dynamics using Fe–H interatomic interaction potential developed by Ramasubramaniam et al. (2009) and modified by the authors of the present work and Fe–Fe matrix potential M07 developed by Malerba et al. (2010). The most energetically favorable configuration of an interstitial H atom is tetrahedral configuration. The energy barrier for H atom migration is 0.04 eV. The highest binding energy of all the considered complexes “vacancy – H atom” and “SIA – H atom” is 0.54 and 0.15 eV, respectively. The binding energy of H atom with edge dislocations in slip systems 〈1 1 1〉{1 1 0}, 〈1 1 1〉{1 1 2}, 〈1 0 0〉{1 0 0}, 〈1 0 0〉{1 1 0} is 0.32, 0.30, 0.45, 0.54 eV, respectively. The binding energy of H atom in VHn complexes (n = 1 … 15) decreases from 0.54 to 0.35 eV with increasing of n from 1 to 6. At n > 6, it decreases to ∼0.1 eV. The temperature dependences of hydrogen isotopes (P, D, T) diffusivities have been calculated for the temperature range 70–1800 K. Arrhenius-type dependencies describe the calculated data at temperatures T < 100 K. At T > 250 K, the temperature dependencies of the diffusivities DP, DD, DT have a parabolic form. The diffusivities of H isotopes are within 10% at room temperature. The isotope effect becomes stronger at higher temperatures, e.g., ratios DP/DD and DP/DT at 1800 K equal 1.23 and 1.40, respectively.
Crystallography Reports, 2014
The sink efficiency of perfect dislocations for self point defects (interstitials and vacancies) ... more The sink efficiency of perfect dislocations for self point defects (interstitials and vacancies) in fcc copper crystal has been calculated by the kinetic Monte Carlo method in a temperature range of 293-1000 K and a range of dislocation densities from 1.3 × 10 12 to 3.0 × 10 14 m-2. Screw, mixed, and edge dislocations with a Burgers vector 1/2〈110〉 in different slip systems are analyzed. The interaction energies of self point defects with dislocations are calculated using the anisotropic theory of elasticity. Analytical expressions are proposed for the dependences of the calculated values of dislocation sink efficiency on temperature and dis location density.
Journal of Nuclear Materials, 2003
ABSTRACT
Crystallography Reports, 2010
The energetic, crystallographic, and diffusion characteristics of self point defects (SPDs) (vaca... more The energetic, crystallographic, and diffusion characteristics of self point defects (SPDs) (vacan cies and self interstitial atoms (SIAs)) in body centered cubic (bcc) iron crystal in the absence of stress fields have been obtained by the molecular statics and molecular dynamics methods. The effect of elastic stress fields of dislocations on the characteristics of SPDs (elastic dipoles) has been calculated by the methods of the anisotropic linear theory of elasticity. The SPD diffusion in the elastic fields of edge and screw dislocations (with Burgers vectors 1/2 〈111〉 and 〈100〉) at 293 K has been studied by the kinetic Monte Carlo method. The values of the SPD sink strength of dislocations of different types are obtained. Dislocations are more effective sinks for SIAs than for vacancies. The difference in the sink strengths for SIAs and vacancies in the case of edge dislocations is larger than the screw dislocations.
Crystallography Reports, 2010
The crystallographic, energetic, and kinetic characteristics of intrinsic point defects (vacancys... more The crystallographic, energetic, and kinetic characteristics of intrinsic point defects (vacancyself interstitial atom) in stable, metastable, and saddle configurations in hcp zirconium crystal have been cal culated by the molecular statics method. The spatial dependences of the interaction energies of intrinsic point defects and stress fields of rectilinear dislocations with Burgers vectors of 1/3[11 0], 1/3 [11 3], and [0001] have been found within the anisotropic linear theory of elasticity. The most likely trajectories of intrin sic point defects in dislocation stress fields (trajectories with minimum energy barriers for motion) have been constructed. Such trajectories result in dislocation only for the interaction of self interstitial atoms with an edge dislocation that has a Burgers vector of 1/3 [11 3].