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MM: Fachverband Metall- und Materialphysik
MM 32: Topical Session: Defect Phases I
MM 32.7: Talk
Wednesday, March 29, 2023, 17:45–18:00, SCH A 216
Temperature-dependent impact of antiphase boundaries on properties of Fe3Al — •Martin Friák1,2, Miroslav Černý2,3, and Mojmír Šob4,1 — 1Institute of Physics of Materials, Czech Academy of Science, Brno, CZ — 2Central European Institute of Technology (CEITEC), Brno University of Technology, Brno, CZ — 3Faculty of Mechanical Engineering, Brno University of Technology, Brno, Czech Republic — 4Department of Chemistry, Faculty of Science, Masaryk University, Brno, CZ
We have performed a quantum-mechanical study of the influence of antiphase boundaries (APBs) on the temperature dependence of selected materials properties of Fe3Al. We show that the studied APBs very strongly affect thermal vibrations of Fe3Al and reduce the width of the band gap in phonon frequencies. Our results also show that the Fe3Al with APBs exhibits higher volumetric thermal expansion than the defect-free Fe3Al. The computed free energy of APBs is found to be strongly temperature-dependent. It is lower than the static-lattice temperature-independent APB energy and the reduction is enhanced by increasing temperature (to 76% at T = 700 K). We have also addressed the discrepancy between the experimental bulk modulus and previous theoretical results obtained for the defect-free Fe3Al. Due to the presence of APBs, the bulk modulus is reduced from the value of 173 GPa, that corresponds to the defect-free Fe3Al, to 153 GPa, i.e. very close to the experimental value of 147 GPa (at T = 0 K). For details see Intermetallics 151 (2022) 107746, DOI:10.1016/j.intermet.2022.107746.