High strain rate superplasticity in an Al-Mg alloy containing scandium

1. A cast alloy of Al-3% Mg-0.2% Sc was subjected to equal-channel angular pressing at room temperature to a total strain of ∼8. Following ECA pressing, the microstructure was heterogeneous with small areas of subgrains interspersed within larger areas of grains having boundaries with high angles of misorientation. The average grain size was ∼0.2 μm. 2. Static annealing revealed that the microstructure was thermally stable because of the presence of the dilute scandium addition. The grain size remained at <1 μm after annealing for 1 hour at temperatures up to 673 K. 3. The alloy exhibited high strain rate superplasticity with an elongation of 1030% when tested in tension at 673 K using an initial strain rate of 3.3 × 10-2 s-1.