Berlin 2018 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 69: Structural Materials (Steels, light-weight materials, high-temperature materials)

MM 69.1: Talk

Friday, March 16, 2018, 09:30–09:45, H 0106

Dislocation dissociations in C11b MoSi2 and their impact on its plastic deformation — Václav Paidar¹, Miroslav Čák², •Mojmír Šob^3,4,5, and Václav Vitek⁶ — ¹Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czechia — ²ICAMS, Ruhr-Universität Bochum, Germany — ³Central European Institute of Technology, CEITEC MU, Masaryk University, Brno, Czechia — ⁴Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Brno, Czechia — ⁵Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czechia — ⁶Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, U.S.A.

Using the DFT calculated γ-surfaces possible metastable stacking faults have been found for the most common slip planes {013) and {110) in MoSi2. These calculations reveal three distinct stacking faults on {013) planes and one stacking fault on {110} plane. Owing to such multiplicity of metastable stacking faults there is a large number of possible dislocation dissociations. These dislocation splittings are analysed using the anisotropic elasticity and relevant stacking faults. The results show that the only dissociations of the <331] dislocations favoured over the complete undissociated dislocations are on {013) planes either in one or two planes of this type. Splitting into {110) planes are never favored. For loading along the [001] axis the dislocation glide may take place at high temperatures when the cross slip releases the sessile screw dislocations on two {013) planes.