Abstract
A sub-micrometer grain size was introduced to a Zr and Sc modified AA7075 aluminium alloy using the method of equal-channel angular pressing. Room temperature tensile tests together with microhardness measurements revealed that the refinement of the microstructure had been accompanied by a substantial increase in room temperature strength. The acquired microhardness values were also used to determine the deformation dead zone within the ECAP billet. TEM observations documented a reasonable stability of the microstructure up to the temperature of 623 K. At this temperature, the material exhibited high strain rate superplasticity with an elongation to failure of 520 %.

Key words
ultra-fine grained Al alloys, ECAP, high strain rate superplasticity

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