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MM: Fachverband Metall- und Materialphysik
MM 18: Poster Session I
MM 18.16: Poster
Montag, 16. März 2020, 18:15–20:00, P4
DFT characterization of β- and δ- intermetallic Al-Fe-Si phases — •Nebahat Bulut1, Hanka Becker2, Andreas Leineweber2, and Jens Kortus1 — 1TU Bergakademie Freiberg, Institute of Theoretical Physics, Germany — 2TU Bergakademie Freiberg, Institute of Materials Science, Germany
The β-Al4.5FeSi and δ-Al3FeSi2 phases are known stable phases of Fe-containing Al-Si alloys. Despite the known stoichiometry of the β- and δ- phase the positions of the Al and Si atoms in these Al-Fe-Si intermetallic phases could not be uniquely determined experimentally [1]. Therefore possible positions of Si atoms in these intermetallic phases were investigated using the density functional theory (DFT) code Quantum Espresso, which is based on plane waves and pseudopotentials [2]. For all calculations the PBE exchange-correlation functional has been used.
For both β- and δ- phase different arrangements of Si atoms in the Al-Fe-Si intermetallics were considered.
We compare the energies of these arrangements (1) relaxing the atomic positions keeping the unit cell volume constant and (2) fully relaxing atomic positions and unit cell shape and volume.
As result we find that arangements where the Si atoms are not nearest neighbours are energetically favored.
Further, we analyze the electronic structure and investigate the bonding.
[1] Becker et al., JAC 780:917-929, (2019)
[2] P. Giannozzi et al., J.Phys.Condens.Matter 21, 395502 (2009)