Achieving exceptionally high superplasticity at high strain rates in a micrograined Al–Mg–Sc alloy produced by friction stir processing

Friction stir processing (FSP) was applied to extruded Al–Mg–Sc alloy to produce fine-grained microstructure with 2.6μm grains. A maximum elongation of 2150% was achieved at 450°C and a high strain rate of 1×10−1s−1. Although the grains obtained by FSP were much larger than those by other techniques, such as equal-channel angular pressing, approximately the same superplasticity was achieved at an even higher strain rate in the FSP alloy.