Abstract
The work deals with the effect of the ECAP treatment on the microstructure and mechanical properties of the AA2030 alloy.There were four cycles of deformation in the 105°-tool for pre-annealed samples, which ensured the preparation of an ultrafine-grained structure, both along the Bc route and along the C route.The average grain size after four cycles of ECAP was 420 nm for the samples treated along the Bc route and 380 nm for the samples treated along the C route.In the structure of the metal, there were inclusions of Al20Cu2Mn3, the q-phase and Al7Cu3Fe.After three cycles of the ECAP treatment, the alloy was hardened by 54 % along the Bc route and 60 % along the C route compared with the annealed condition.The overall increase in the microhardness was 138 % for the samples treated along the Bc route and 113 % for the samples treated along the C route.Because of prolonged aging, the number of dispersoids increased at room temperature, long rod-like inclusions transformed into more favourable short ones with a length of up to 150 nm, and partial dissolution of the q-phase was observed.After the aging, the grain boundaries were predominantly equilibrium, thin, without the moire contrast, and a rearrangement of dislocation walls into subgrain boundaries was found.In addition, after the prolonged natural aging, large grains with non-equilibrium boundaries fragmented into subgrains with sizes of 100-300 nm.Keywords: SPD,