High strain rate superplasticity in an Al-Mg-Sc-Zr alloy processed via simple rolling

The superplastic behavior of Al-Mg-Sc-Zr samples with standard gauge size (18 mm by 6 mm) were prepared using simple rolling and were tested in the temperature range from 450 °C to 525 °C at strain rates ranging from 1.67×10-3 s−1 to 1×10-1 s−1. With proper deformation parameters, the Al-Mg-Sc-Zr alloy has an elongation to failure much higher than 300% and the maximum elongation is 740%. The Microstructure and dislocation substructure investigation using optical microscopy (OM) and transmission electron microscopy (TEM) revealed a dynamic recrystallization in it. The grain size and activation energy on the deformation mechanisms of superplastic is discussed. Results also show that these nano-scale Al3(Sc1−xZrx) particles play an important role in the superplastic process. Al6FeMn particles were found to induce the formation and growth of cavities, which can lead to the fracture of specimens.