Effect of Initial ⟨0001⟩||RD Orientation on the Rolling Texture of AZ91 Alloy

In the present research, for the first time, the < 0001 >||RD as an initial texture for suppression of basal slip and the continuous beta-Mg17Al12 phase for inhibition of extension twinning was used, simultaneously, to obtain non-basal orientation in the asymmetrically cold-rolled AZ91 magnesium alloy. The as-cast alloy consisted of alpha + beta eutectic and alpha-Mg with two intermetallic phases (Mg17Al12 and Al8Mn5) which were located along grain boundaries and also inside the alpha grains. After 8 and 15% rolling reductions, the fraction of high-angle grain boundaries increased which was mainly due to the formation of many contraction and/or double twins. It was found that achieving non-basal texture in magnesium alloys during rolling deformation is possible. This was firstly due to the primary strong < 0001 >||RD orientation, which was not favored for both prismatic and basal slips. Secondly, the incoherent beta located at the boundaries of alpha grains suppressed the extension twin nucleation (which quickly strengthens basal texture) but did not inhibit the nucleation of double and contraction twins.