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MM: Fachverband Metall- und Materialphysik
MM 53: Microstructure and Phase Transformations II
MM 53.2: Talk
Thursday, March 10, 2016, 12:00–12:15, H39
Core-shell structure of precipitates in the Al-Sc-Zr system — •Yulia Buranova1, Ankit Gupta2, Vladislav Kulitckii3, Tilmann Hickel2, Sergiy V. Divinski1, and Gerhard Wilde1 — 1Institut für Materialphysik, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str.10, 48149 Münster, Germany — 2Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf 40237, Germany — 3Laboratory of Mechanical Properties of Nanoscale Materials and Superalloys, Belgorod State University, Pobeda 85, Belgorod 308015, Russia
Aluminum alloys containing scandium show excellent mechanical properties due to the presence of Al3Sc precipitates, which control the dislocation and grain boundary motion during the recrystallization processes. An addition of Zr can further improve the properties due to the formation of Al3(Sc,Zr) dispersoids, which are more stable at elevated temperatures. In this work we investigate a commercial aluminum alloy AA5024, containing Sc, Zr, Ti and Mg additions. The particles size, chemistry and distribution were investigated by analytical transmission electron microscopy and geometric phase analysis was applied to map local strains. It is found that the Al(Sc,Zr,Ti)-precipitates reveal complex core-shell structures which are strongly affected by mechanical deformation and heat treatment. The experimental findings are compared with predictions based on DFT calculations, which indicate the existence of a critical size for the appearance of ternary Al3(Sc,Zr) shells. The financial support of DFG within SPP 1713 is gratefully acknowledged.