Hot deformation and processing maps of an Al–5.7 wt.%Mg alloy with erbium

Abstract

The hot deformation behavior of an Al–5.7 wt.%Mg alloy with erbium has been investigated. Compression tests are performed in the temperature range of 300–500 °C and in the strain rate ranging from 0.001 s −1 to 50 s −1 up to a true strain of 0.7. The processing maps are developed at different strains and the standard kinetic analysis has been applied to evaluate the rate controlling mechanisms. The processing maps have exhibited two domains of 350–450 °C at 0.001–0.03 s −1 and 450–500 °C at 0.01–1 s −1, representing dynamic recovery of Al–5.7 wt.%Mg with erbium. The apparent activation energies estimated in these two domains are 180 kJ/mol and 163 kJ/mol respectively, which suggests that cross-slip of dislocation and lattice self-diffusion are the deformation mechanisms. At strain rates higher than 10 s −1, the flow curves demonstrate flow softening behavior, and the flow instability regions reveal mixed microstructure of local deformation and dynamic recrystallization.