Influence of temperature and strain rate on flow stress behavior of twin-roll cast, rolled and heat-treated AZ31 magnesium alloys
(1. Faculty of Materials Science and Technology, Institute of Materials Engineering,
Technical University Bergakademie Freiberg, Freiberg 09599, Germany;
2. Faculty of Materials Science and Technology, Institute of Materials Science,
Technical University Bergakademie Freiberg, Freiberg 09599, Germany)
Technical University Bergakademie Freiberg, Freiberg 09599, Germany;
2. Faculty of Materials Science and Technology, Institute of Materials Science,
Technical University Bergakademie Freiberg, Freiberg 09599, Germany)
Abstract: The effects of temperature and strain rate on the flow stress behavior of twin-roll cast, rolled and heat-treated AZ31 magnesium alloys were investigated under uniaxial tension. At high temperatures, dynamic recovery, continuous dynamic recrystallization, grain boundary sliding and the activation of additional slip systems lead to an improvement of the ductility of the alloys. The elongation to failure is nearly independent of the strain rate between 473 and 523 K at 10-2 s-1 and 10-1 s-1, which is related to the strain rate dependence of the critical resolved shear stress (CRSS) for nonbasal slip. Despite the high temperature, twins are even observed at 573 K and 10-3 s-1 because they have a low CRSS.
Key words: AZ31 magnesium alloy; twin-roll casting; strain rate; temperature; dynamic recrystallization; flow stress