Berlin 2015 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 17: Postersession I
MM 17.8: Poster
Monday, March 16, 2015, 18:00–20:00, Poster E
Correlation between thermodynamic and mechanical properties in binary bcc alloys — •Sandra Hoppe, Sascha B. Maisel, and Stefan Müller — Institute of Advanced Ceramics, Hamburg University of Technology, Hamburg, Germany
When aiming at high-performance tailored metal alloys, it is crucial to understand basic material properties and their relation. Modern computer simulation methods like the cluster expansion with input from density functional theory calculations make the whole configurational space accessible. This way, also metastable structures may be considered, which are experimentally difficult to obtain. Recent results for several face-centered cubic (fcc) binary metal alloys [1] suggest a linear correlation between thermodynamic stability and elastic properties at a fixed stoichiometry. We investigated this relation between the formation enthalpy and the elastic constants c44 and c11 for several binary body-centered cubic (bcc) phases with alloying elements with bcc, fcc or hexagonal close-packed (hcp) equilibrium lattices and at different concentration regimes to understand the basic mechanisms behind this phenomenon. Interestingly, some alloys show similar trends to the fcc alloys, while Ta-W exhibits and anomalous behavior of c44 at the central concentration regime: Energetically favorable structures are mechanically less stable than those further away from the ground-state line.
[1] S. B. Maisel, M. Höfler, and S. Müller. Nature 491 (2012) 740.