Improvement of stretch formability of Mg–3Al–1Zn alloy sheet by high temperature rolling at finishing pass

The effects of increasing rolling temperature from 723 K to 828 K at the last rolling pass on microstructure, texture, mechanical properties and stretch formability of a Mg–3Al–1Zn magnesium alloy previously rolled at 723 K were investigated. In the as-rolled condition, the basal texture strengthens slightly with increasing the rolling temperature whereas it weakens more remarkably after static recrystallization during annealing for the sheets rolled at higher temperatures. Only by increasing the rolling temperature from 723 K to 798 K, the Erichsen value is significantly increased from 4.5 to 8.6 due to the weakened texture for the annealed sheets. Further increasing the last rolling temperature does not appear to further improve the stretch formability.

► Significant improvement in stretch formability of AZ31 alloy sheet can be achieved only by a single finishing pass at a high temperature of 798 K.
► In the as-rolled condition, the basal texture strengthens slightly with increasing the rolling temperature whereas it weakens more remarkably after static recrystallization during annealing for the sheets rolled at higher temperatures.
► Only by increasing the rolling temperature from 723 K to 798 K, the Erichsen value is significantly increased from 4.5 to 8.6 due to the weakened texture.