Assessment of Various DFT-based Methods for Predicting Temperature Dependence of Elastic Constants
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2021.
Publikationen: Thesis / Studienabschlussarbeiten und Habilitationsschriften › Masterarbeit
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TY - THES
T1 - Assessment of Various DFT-based Methods for Predicting Temperature Dependence of Elastic Constants
AU - Jechtl, Tobias
N1 - no embargo
PY - 2021
Y1 - 2021
N2 - The major concern of this thesis is to outline several methodological approaches to compute the temperature dependence of elastic constants of cubic monocrystalline metallic materials from an atomistic point of view and assess them among each other. In particular, the DFT-based VASP software toolkit in combination with the VSC and the HPC cluster of the Montanuniversität Leoben are utilised to perform these CPU-intensive calculations. It is shown that ground-state elastic constants can be depicted as functions of volume and thus are dependent on the distance of neighbouring atoms. Furthermore, the quasiharmonic Debye model and a phonon-based QHA approach within the phonopy software package are employed to predict selected thermal material properties, e.g. the thermal expansion, whereas the latter method is considered to provide more realistic results. Eventually, the elastic constants are constituted as functions of temperature-dependent volume, whereby the outcomes associated with the phonon-based approach are in good accordance with experimental data.
AB - The major concern of this thesis is to outline several methodological approaches to compute the temperature dependence of elastic constants of cubic monocrystalline metallic materials from an atomistic point of view and assess them among each other. In particular, the DFT-based VASP software toolkit in combination with the VSC and the HPC cluster of the Montanuniversität Leoben are utilised to perform these CPU-intensive calculations. It is shown that ground-state elastic constants can be depicted as functions of volume and thus are dependent on the distance of neighbouring atoms. Furthermore, the quasiharmonic Debye model and a phonon-based QHA approach within the phonopy software package are employed to predict selected thermal material properties, e.g. the thermal expansion, whereas the latter method is considered to provide more realistic results. Eventually, the elastic constants are constituted as functions of temperature-dependent volume, whereby the outcomes associated with the phonon-based approach are in good accordance with experimental data.
KW - Dichtefunktionaltheorie
KW - computerunterstützte Materialwissenschaft
KW - elastische Konstanten
KW - Elastizitätstensor
KW - Temperaturabhängigkeit
KW - quasiharmonische Approximation
KW - quasiharmonisches Debye Modell
KW - VASP
KW - phonopy
KW - Phononenberechnungen
KW - temperaturabhängige Materialeigenschaften
KW - Aluminium
KW - Density Functional Theory
KW - DFT
KW - elastic constants
KW - temperature dependence
KW - stress-strain method
KW - energy-strain method
KW - Vienna ab-initio simulation package
KW - VASP
KW - quasiharmonic Debye model
KW - quasiharmonic approximation
KW - phonopy
KW - aluminum
KW - isothermal bulk modulus
KW - thermal expansion coefficient
KW - heat capacity at constant pressure
KW - elasticity tensor
KW - adiabatic elastic constants
M3 - Master's Thesis
ER -