Dynamic softening mechanisms and Zener-Hollomon parameter of Al–Mg–Si–Ce–B alloy during hot deformation

Abstract

Isothermal hot compression tests of Al–Mg–Si–Ce–B alloy at 623–823 K with strain rates of 0.01–50 s−1 were carried out on a Gleeble 3500 thermal simulation tester. The flow behavior of the alloy during thermal deformation was analyzed based on the true stress–strain curves. The Arrhenius equations with Zener-Hollomon (Z) parameter and the processing maps under the conditions with various strains were constructed. It is proved that the alloy was prone to plastic deformation instability under conditions with relatively low temperature, and the optimized deformation parameters were 783–823 K/0.03–0.04 s−1. In addition, the microstructure of the alloy was characterized using TEM and EBSD, and the influence of the Z parameter on the dynamic softening mechanisms was discussed. Both dynamic recovery (DRV) and continuous dynamic recrystallization (CDRX) were observed as the softening mechanisms of the alloy during hot deformation. DRV occurred at high Z values, and DRV and CDRX occurred simultaneously as Z value decreased.