Dresden 2009 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 41: Interfaces II
MM 41.2: Vortrag
Donnerstag, 26. März 2009, 12:00–12:15, IFW D
Ab-initio calculation of stacking-fault energies in Al-based alloys. — Pim Schravendijk1, •Thomas Gnielka2, Christian Elsässer1, and Peter Gumbsch1,2 — 1Fraunhofer IWM, Wöhlerstr. 11, 79108 Freiburg — 2IZBS, Universität Karlsruhe (TH), Kaiserstr. 12, 76131 Karlsruhe
The energetic stability of planar defects as a function of segregated alloying elements in diluted aluminium alloys is studied via ab initio density functional theory (DFT) calculations with the local density approximation (LDA). Several simple and transition metals are chosen as alloying elements and introduced as a substitutional point defects in low concentration (less than 10 at.-%) in the bulk crystal and at planar defects of face-centered cubic aluminum.
Formation energies of planar defects with point defects are determined as a function of the alloying elements’ species and concentration. This requires DFT total-energy calculations, for atomistic supercells of the planar defects and point defects, as well as for single crystals of experimentally known intermetallic phases of the alloying elements with the aluminium host metal.
The procedure is applied to extrinsic and intrinsic stacking faults as well as to twin boundaries, and it provides a practical and straightforward estimation for interface and segregation energies in alloys.