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MM: Fachverband Metall- und Materialphysik

MM 30: Topical Session: Thermodynamics at the nano scale III - Novel experimental and theoretical approaches

MM 30.3: Talk

Tuesday, April 1, 2014, 16:15–16:30, BAR 205

Ab initio prediction of solvus lines in Al alloys: The importance of anharmonic contributions — •Albert Glensk, Blazej Grabowski, Tilmann Hickel, and Jörg Neugebauer — Max-Planck-Institut für Eisenforschung, Düsseldorf

The prediction of alloy phase diagrams without any experimental input is a major challenge in materials science. First-principles studies including temperature effects in the harmonic approximation have already demonstrated to provide a qualitative agreement with CALPHAD phase diagrams, but truly quantitative predictions are rare. Recent first-principles calculations on point defects have shown that a highly accurate computation of formation free energies is possible up to the melting temperature, if all excitation mechanisms, in particular anharmonic excitations, are taken into account [1]. Applying these methods, we have studied the solvus line of Si in Al, giving access to the Al-rich region of the Al-Si phase diagram. We will discuss the methodological challenges and the unexpectedly large impact of anharmonic lattice excitation on these results.

[1] B. Grabowski et al, PRB 79, 134106 (2009)