Equal channel angular extrusion (ECAE) has been used to develop an ultrafine grain (UFG) structure, with a 0.4 μm grain size, in Al-alloy 1560. The structure and mechanical properties, including toughness, have been investigated in the as-deformed condition and after annealing. On annealing in the temperature range 200-350°C abnormal growth of discrete grains to several microns in size occurred, whereas when annealed at higher temperatures the UFG structure coarsened uniformly. The as-deformed and lightly annealed states, both with UFG structures, showed substantially higher strengths, but lower ductility and toughness, compared to UFG material annealed to produce a 5 μm grain size.