ODS nanodaļiņu veidošanās bcc-Fe tilpumā sākuma stadiju modelēšana no pirmajiem principiem
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Latvijas Universitāte
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Abstract
ODS (angļu: Oxide-Dispersion Strengthened) tēraudus ar Y2O3 piemaisījumiem ir iespējams
izmantot kā strukturālo materiālu nākotnes termiskās sintēzes reaktoriem. Tika
veikti vairāki eksperementāli tēraudu pētījumi, bet ir svarīgi arī saprast mehānismus,
kā Y2O3 nanodaļiņas uzvedas tēraudā. Šim nolūkam tika veiktas vairākas modelēšanas
procedūras. Šajā darbā ir parādīti rezultāti, iegūtie ar DFT aprēķiniem, izmantojot
VASP programmu. Tika pētītas sistēmu enerģijas atkarībā no Y atoma, vakanču vai
O atoma klātbūtnes un savstarpēja novietojuma bcc-Fe matricā. Tika pētītas sekojošas
konfigurācijas: Y dažādās pozīcijās ar un bez vakancēm, O dažādās pozīcijas, vakances
un O oktaedriskā pozīcijā mijiedarbība atkarībā no attāluma, vakance–Y–vakance un O
oktaedriskā pozīcijā mijiedarbība atkarībā no O novietojuma (vienam un diviem O).
ODS (Oxide-Dispersion Strengthened) steels with Y2O3 are possible candidates for structural application in future nuclear fusion reactors. The great ammount of experimental research has been made so far, however, it is also important to understand the mechanics and kinetics of Y2O3 nanoparticles’ behaviour. For this purpouse theoretical modelling has to be performed. This paper presents DFT calculations, using the computer code VASP. We have studied the influence on the system’s energy of Y, O and vacancy defects in bcc-Fe matrix. The following configurations have been studied: Y and Y with vacancies in different positions, O in different positions, the dependance of energy from the distance between O in octahedral site and vacancy, vacancy–Y–vacancy and O in octahedral site system’s energy for different positions of O (for one and two O).
ODS (Oxide-Dispersion Strengthened) steels with Y2O3 are possible candidates for structural application in future nuclear fusion reactors. The great ammount of experimental research has been made so far, however, it is also important to understand the mechanics and kinetics of Y2O3 nanoparticles’ behaviour. For this purpouse theoretical modelling has to be performed. This paper presents DFT calculations, using the computer code VASP. We have studied the influence on the system’s energy of Y, O and vacancy defects in bcc-Fe matrix. The following configurations have been studied: Y and Y with vacancies in different positions, O in different positions, the dependance of energy from the distance between O in octahedral site and vacancy, vacancy–Y–vacancy and O in octahedral site system’s energy for different positions of O (for one and two O).