Dresden 2014 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 38: Structural materials
MM 38.2: Talk
Wednesday, April 2, 2014, 10:30–10:45, IFW B
The effect of extreme uniaxial and biaxial loading conditions in transition-metal disilicides: an ab initio study — Dominik Legut1, •Martin Friák2,3,4, Mojmír Šob4,3,5, and Jörg Neugebauer2 — 1Nanotechnology Centre & IT4Innovations, VSB-Technical University of Ostrava, Ostrava, Czech Republic — 2Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany — 3Institute of Physics of Materials, AS CR, v.v.i. Brno, Czech Republic — 4Central European Institute of Technology (CEITEC MU), Masaryk University, Brno, Czech Republic — 5Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
Transition-metal disilicides constitute a promising basis for a new generation of high-temperature structural materials that can significantly improve the thermal efficiency of energy conversion systems and advanced engines. Although they have been studied quite intensively, the complexity of their mechanical behavior is still not completely understood. Employing first-principles (ab initio) calculations of electronic structure, we investigate the effect of uniaxial loading for disilicides with hexagonal C40 structure, namely for NbSi2, CrSi2, VSi2 and TaSi2, and compare their behavior with previously studied C11b structure disilicides. Further, the C40 structure disilicides are subjected to biaxial loading and the values of strains are extended up to their extreme levels, beyond materials stability limits represented here by the values of theoretical tensile strength. We find a direct correspondence between the electronic structure characteristics and the onset of strength instability.