Dresden 2017 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MM: Fachverband Metall- und Materialphysik
MM 34: Poster session II
MM 34.36: Poster
Dienstag, 21. März 2017, 18:30–20:30, P4
Diffusion in intermetallic AlAu4: MD study down to temperatures relevant to wire bonding — •Mohammed Guerdane — Karlsruhe Institute of Technology, IAM-CMS, Karlsruhe
We show the ability of long time (∼ 1 µs) molecular dynamics modeling to provide quantitative diffusion coefficients for the compound AlAu4 (β-Mn type), down to temperatures (∼ 200 ∘C) that are relevant to Al-Au wire bonding. Concerning Au diffusion, our results agree quite well with DFT calculations of the vacancy-formation energy, the activation energy, and the diffusion mechanisms. The van Hove correlation-function analysis shows that Au diffusion takes place mainly on the Wyckoff b sublattice. Moreover, we shed light on the high-temperature region, as the stability limit T⋆ of AlAu4 is approached and unfavorable jumps contribute to the diffusivity. This concerns, for instance, jumps generating antisites defects. The latter lead to a massive disorder which ends up in a phase change to a distorted fcc structure at T⋆. Including the melting temperature in the potential-fitting procedure seems to be an effective way to gauge the temperature scale and properly capture the order of magnitude of diffusion.