Regensburg 2016 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 53: Microstructure and Phase Transformations II

MM 53.3: Vortrag

Donnerstag, 10. März 2016, 12:15–12:30, H39

Mechanical behaviour and deformation mechanisms of a Zn-Al-Cu-Mg alloy — •Zhicheng Wu, Stefanie Sandlöbes, Günter Gottstein, and Sandra Korte-Kerzel — Institut für Metallkunde und Metallphysik, RWTH Aachen, D-52056 Aachen, Germany

The microstructure, mechanical properties and deformation behaviour of a gravity-cast alloy ZnAl4Cu1Mg0.3 (wt.%) was studied at different temperatures and strain rates using ex-situ and in-situ tensile tests in conjunction with scanning electron microscopy, electron backscatter diffraction, transmission electron microscopy and atom probe tomography. The alloy revealed two distinct deformation regimes, i.e. work hardening and brittle fracture at room temperature and/or elevated strain rates, and work softening and ductile fracture at elevated temperatures and/or low strain rates. Further, we identified precipitates of a non-equilibrium Zn_xAl_1−x (x≥0.7) transition phase or Guinier-Preston zone which partly dissolved during deformation at elevated temperatures. The partial dissolution of these precipitates is assumed to partially account for the observed increase in ductility at elevated temperatures, but might also contribute to the long-term softening of Zn-Al alloys that currently poses one of the major drawbacks to their application.