Strength, ductility and impact toughness of the magnesium alloy az31b after equal-channel angular pressing

The room temperature strength, ductility and impact toughness of the commercial Mg wrought alloy AZ31B was investigated after equal-channel angular pressing (ECAP). It is shown, that the introduction of a beneficial texture allows a tremendous increase of ductility. An equivalent strain of ∼4.4 at 260°C processing temperature increases the elongation to failure for example from ∼12% to ∼35% (strain rate 10–3 s-1). Simultaneously, the yield stress drops from 225 MPa to 80 MPa. Since the strain hardening capability is increased, an ultimate tensile stress close to that of the commercial material is reached. Instrumented Charpy impact toughness tests reveal also an increase of toughness, whereas crack initiation contributes in particular. Additionally it is shown, that the decrease of the processing temperature necessitates the reduction of the feeding rates to ensure homogenous plastic deformation without shear localisations on the one hand, but gains a higher strength, ductility and toughness on the other hand.