Berlin 2015 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 49: Interfaces I: Structure and Segregation
MM 49.4: Vortrag
Donnerstag, 19. März 2015, 11:00–11:15, H 0107
Tensile strength of Ni grain-boundary with segregated sp-impurities — •Miroslav Černý1,2,3, Petr Šesták1,2, Petr Řehák1,2,3, Monika Všianská1,3, and Mojmír Šob1,3,4 — 1Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Brno, Czech Republic — 2Faculty of Mechanical Engineering, Brno University of Technology, Brno, Czech Republic — 3Central European Institute of Technology, Brno, Czech Republic — 4Faculty of Science, Masaryk University, Brno, Czech Republic
Grain boundaries (GB) represent extended planar defects with a crucial effect on macroscopic strength of polycrystalline materials. In this first principles study, we calculate the ideal tensile strength of Σ5(210) tilt GB in nickel crystal under uniaxial loading applied perpendicularly to the GB plane. A repeat cell containing 64 atoms is subjected to three different modes of simulated deformation comprising rigid grain shift, uniaxial deformation with optimized atomic coordinates and fully optimized uniaxial loading (ionic positions in the supercell as well as the cell shape are optimized at each step of deformation). Results for these models are compared and tensile strength of clean GB is compared with that of GB with segregated impurities (S and Al) and with the results of previous studies. Differences in computed values show not only the effect of the impurities on the ideal strength but also the importance of full lattice optimization during the simulation of tensile test.