Effect of Al addition on microstructure, texture evolution and mechanical properties of Mg-1Zn-1Y-0.1Mn alloy sheets

• The addition of Al element in Mg-Zn-RE alloy system does not refine grain size but changes the dominant second phase from Mg 3 Zn 3 Y 2 to Al 2 Y phase. • A critical Al content of ≥ 0.5 wt. % transforms the texture from weak TD-split/TD-broad to strong basal texture, degrading room-temperature formability. • Texture evolution is not driven by second phase formation but by a significant reduction in dissolved Y element, which suppresses prismatic ⟨a⟩ slip activity. • The study suggests that Y content must be at least double the Al content (wt. %) to retain texture weakening effects and improve formability. The microstructure and texture evolution of Mg-xAl-1Zn-1Y-0.1Mn alloys are systematically analyzed. There is no effect of Al addition on grain refinement in the Mg-1Zn-1Y-0.1Mn alloy, but the addition of 0.5 wt. % or more Al element dramatically changes texture from a weak texture to a strong basal texture. The predominant second phase particle of Mg 3 Zn 3 Y 2 phase in the Mg-1Zn-1Y-0.1Mn alloy changes to Al 2 Y phase by the addition of only 0.1 wt. % Al element, and the concentrations of dissolved Y element in the 0Al, 0.1Al, 0.3Al, 0.5Al and 1Al alloys are 0.50, 0.31, 0.23, 0.15 and 0.06 wt. %, respectively. Although the 0.5 wt. % or more Al-added alloys have higher Schmid factor for prismatic 〈a〉 slip than the 0.3 wt. % or less Al-added alloys, the lower Al containing alloys show much higher activity of prismatic 〈a〉 slip than the higher Al containing alloys. It demonstrates that the addition of high amount of Al element in Mg-Zn-RE alloy dramatically decrease the dissolved Y element, resulting in a significant deterioration of activity of prismatic 〈a〉 slip and consequently a poor formability at room temperature.