Dresden 2020 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 18: Poster Session I

MM 18.16: Poster

Monday, March 16, 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-Al_4.5FeSi 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)