Characteristic features of microstructure of ALMg5 deformed to large plastic strains

The evolution of the microstructure of the AlMg5 alloy was analysed and its typical features were determined. Large degrees of deformation were achieved using the cyclic extrusion compression method. The microstructure was analysed by transmission electron microscopy and scanning electron microscopy. Dense dislocation walls and microbands cutting randomly distributed tangles of dislocations, were observed. After a true strain ϕ=16, mutual crossing of microbands led to a ‘subgrain like’ microstructure. Large disorientation angles up to 60° were found between some neighbouring ‘subgrains’, but generally angles were lower (below 15°).