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 β-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 α + β eutectic and α-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 β located at the boundaries of α grains suppressed the extension twin nucleation (which quickly strengthens basal texture) but did not inhibit the nucleation of double and contraction twins.