Structure development during superplastic deformation of an Al-Mg-Sc-Zr alloy

The Al-1.5 Mg-0.2 Sc-0.18 Zr (wt.%) alloy prepared using equal-channel angular pressing exhibits superplastic behavior in the temperature range from 573 to 773 K at strain rates of 10−2 s−1. Microstructure investigation using the electron back-scattered diffraction revealed a gradual elimination of low-angle boundaries and slight grain growth during superplastic deformation. The surfaces of samples slightly strained under superplastic conditions were investigated using light microscopy, electron scanning microscopy and atom force microscopy. An inhomogeneous distribution of grain-boundary sliding was observed.