Multi-scale simulations of multi-component phases

01.01.2011 - 31.12.2014
Forschungsförderungsprojekt
The aim of this project is threefold: (i) Use advanced DFT techniques to explore the physical properties of ordered binary and multi-component compounds, concentrating in this first part of the SFB on intermetallic compounds with technologically interesting properties (such as the Ti-based superelastic-superplastic “gum-metal” alloys). (ii) To combine ab-initio DFT calculations with advanced statistical-mechanical tools for exploring the configuration space of disordered multi-component systems, with the aim to extend the applicability of DFT calculations far beyond the scale accessible to current supercell techniques. Our approach will be based on a Cluster Expansion (CE) strategy, using DFT calculations to derive all relevant effective cluster interactions (ECI) from first principles and for calculating the vibrational frequency spectrum, entropy and free energy. Monte Carlo methods will be used to derive the configurational entropy. This will allow to determine the composition-temperature phase diagram, study temperature-induced structural transformations, and to determine the variation of elastic and plastic properties and of the theoretical tensile and shear strength as a function of temperature and composition. (iii) At even larger length scales, Monte Carlo and kinetic Monte Carlo simulations based on different atomic interaction parameters, diffusional jump frequencies and process parameters derived from DFT calculations combined with CE methods will be used to study the microstructure, concentrating on the incipient formation of precipitates (nucleation) in metastable alloys. As a preliminary step for the long term prospect of applying CE also for oxides, the physical properties of selected oxide compounds with varying oxygen concentration will be studied by hybrid functional methods.

Personen

Projektleiter_in

Projektmitarbeiter_innen

Institut

Grant funds

  • FWF - Österr. Wissenschaftsfonds (National) National Research Network (NFN) Austrian Science Fund (FWF)

Forschungsschwerpunkte

  • Special and Engineering Materials: 20%
  • Computational Materials Science: 80%

Schlagwörter

DeutschEnglisch
DichtefunktionaltheorieDensity Functional Theory
Cluster EntwicklungCluster Expansion
Monte Carlo SimulationenMonte Carlo simulations
PhasenuwandlungenPhase Transformations

Externe Partner_innen

  • Universität Wien, Institut für Physikalische Chemie

Publikationen