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 Mg₃Zn₃Y₂ phase in the Mg-1Zn-1Y-0.1Mn alloy changes to Al₂Y 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.

The effects of various alloying elements on the performance of Mg-Mg₂Ni hydrogen storage alloys were investigated by performing first-principles density functional theory calculations. We examined the important characteristics of hydrogen storage alloys by considering both Mg-based solid solution and Mg₂Ni-based intermetallic compound phases, where the hydride forms are MgH₂ and Mg₂NiH₄, respectively. In particular, qualitatively valid information for predicting changes in plateau pressures in the pressure-composition-temperature (PCT) curve was provided by calculating changes in the energy of related hydrogenation reactions. The effects of alloying elements on volume changes due to hydrogenation reactions were also obtained to provide additional criteria for the practical use of hydrogen storage alloys. For the Mg₂Ni-based intermetallic compound, we examined the site preference of each alloying element, considering the designated stoichiometry of the base alloy. Based on the revealed site preferences, the effects of various possible alloying elements on the properties of Mg₂Ni-based hydrides were also examined. Electronic structure analyses were further conducted to elucidate the detailed mechanisms underlying the role of the additional solute elements.