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Extruded AZ31 alloy was processed by equal channel angular pressing (ECAP) up to 12 passes at 180 °C following route Bc, i.e. rotating the sample 90° between individual passes. Microstructure evolution was investigated using EBSD and TEM, as a function of strain imposed by ECAP. The first ECAP pass resulted in the formation of a new texture component which relates to the bimodal grain structure observed in this specimen. The grains larger than 10 μm show the orientation changes corresponding to the ECAP shear, which is characterised by the rotation of the basal poles by approximately 40° from the initial orientation. The fine grains with the average size of 1 μm maintain the initial orientation. The character of the bimodal grain structure and the distinct texture components between large and small grains remained unchanged up to 4 ECAP passes. Further ECAP pressing to 8 and 12 passes leads to a grain refinement through the whole sample volume and the orientation changes of all grains corresponding to the ECAP shear.

In present investigation, the plastic deformation behavior of an AZ31 alloy during accumulative roll bonding (ARB) process was analyzed by the rigid-plastic finite element method (FEM). The finite element simulations were performed relying on the true stress–true strain behavior of the experimental alloy obtained through hot-compression testing. The equivalent plastic strain and shear strain were predicted throughout the sheet thickness. Moreover, the influence of the friction between roller/sheet and sheet/sheet on the strain distribution was analyzed. The effect of temperature on the equivalent plastic strain was also characterized. The results indicated that any increase in friction coefficient ended to an increase in equivalent plastic strain and strain gradient. Furthermore, it was found that as the temperature increased the accumulated strain decreased. This was resulted in more homogeneous deformation throughout the sheet thickness.

Stretch formability of Mn-free AZ31 Mg alloys rolled at 618 and 723 K was investigated at room temperature. The specimen rolled at 723 K showed superior stretch formability to that of the specimen rolled at 618 K. The (0002) plane texture of the specimen rolled at 723 K exhibited a low texture intensity compared with that of the specimen rolled at 618 K. It is suggested that the modification of basal texture by the high temperature rolling contributes to activation of basal slips, resulting in an enhancement of the stretch formability. Besides, it is suggested that coarse grain size of a Mn-free AZ31 alloy seems to enhance a stretch formability, because twins become easily generated during tensile loading.

Stretch formability of a Mn-free AZ31 Mg alloy rolled by the reverse cross-roll rolling was investigated at room temperature. The specimen rolled by the reverse cross-roll rolling showed superior stretch formability to that of the reference specimen. The (0002) plane texture of the specimen by the revere cross-roll rolling exhibited a low texture intensity and a circular spread of the basal pole from the ND compared with those of the reference specimen. It is suggested that the modification of basal texture by the reverse cross-roll rolling contributes to an activation of basal slip and twinning, resulting in an enhancement of the thickness-direction strain and tensile ductility. Besides, it is suggested that the coarse grain size of a Mn-free AZ31 alloy seems to enhance a stretch formability, because twins become easily generated during loading.