AbstractIt is now recognized that superplasticity requires a very small grain size, typically > 10 μm. A further reduction in grain size, to the submicrometer or nanometer level, offers the potential for attaining superplasticity at both faster strain rates and lower temperatures. This paper reports an investigation of the microstructure and tensile behavior of an Al-3% Mg-0.5% Zr alloy after processing by equal-channel angular pressing to an equivalent true strain of ∼8.