SKM 2023 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 32: Topical Session: Defect Phases I
MM 32.5: Vortrag
Mittwoch, 29. März 2023, 17:15–17:30, SCH A 216
Planar defects in intermetallic MgxAl2−xCa Laves phases — •Ali Tehranchi1, Tilmann Hickel1,2, and Jörg Neugebauer1 — 1Max-Planck-Institut für Eisenforschung GmbH, D-40237 Düsseldorf, Germany — 2Bundesanstalt für Materialforschung und -prüfung (BAM)
The intermetallic Laves phases that are present in Mg-based alloys when adding Ca and Al beyond the solubility limit have a beneficial impact on the mechanical properties of these alloys. For example, Laves phases have been observed to enhance the alloy’s creep resistance and to extend their application to higher-temperature domains. However, the mechanism of deformation of these phases and their effect on the surrounding matrix is not fully understood. Laves phases not only contain planar defects but also their motifs are observed in planar defects in Mg. In this work, using the concept of defect phase diagrams, we study hcp-like planar defects in the C36 phase and the thermodynamically stable Laves-type planar defects in Mg-based alloys. We show, that while conventional bulk thermodynamic phase diagrams fail to predict the experimentally observed phases the predictions obtained by the defect phase diagrams match well with the experiments. Defect phase diagrams thus provide a powerful tool to predict and interpret the formation of chemically and structurally complex motives at defects as function of experimentally accessible and controllable parameters such as temperature or alloy composition.