Microstructure, grain refinement and hardness of Al–3%Mg aluminium alloy processed by ECAP with helical die

In the present research, commercial Al–3%Mg aluminium alloy was subjected to the ECAP processing using a modified die with a helical 30° exit channel. The changes in microstructure were characterized by light microscopy, electron backscatter diffraction (EBSD) and TEM. Mechanical properties were compared based on hardness measurement. It is also shown that such modification of ECAP die enhances grain refinement due to the vortex-like flow of metal during subsequent deformations. The results of the metallographic study showed that microstructure is refined due to the interactions and intersections of the deformation bands. The mechanical properties examinations display a significant improvement after the first ECAP pass and less significant increase with subsequent passes.