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.

This study investigates zinc’s (Zn) key role in enhancing the precipitation kinetics and refinement of Mg₁₇Al₁₂ and Mg₂Sn phases in magnesium alloys through trace sodium (Na) additions. Magnesium alloys with varying compositions of aluminum (Al), tin (Sn), Zn, and Na were prepared and aged at 453 K. Microstructural analyses were conducted using transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), and atom probe tomography (APT). Trace additions of Na significantly enhanced the precipitation responses of both Mg₁₇Al₁₂ and Mg₂Sn phases. When Zn was co-added with Na, as in the ATZ641N3 alloy (Mg–6Al–4Sn–1Zn–0.3Na), there was a pronounced refinement in precipitate morphology and acceleration of precipitation kinetics. The ATZ641N3 alloy achieved a peak hardness of 103 Hv at 36 hours, compared to 91 Hv at 72 hours for the ATZ641 alloy without Na. The simultaneous addition of Zn and Na led to the formation of Sn–Na–Zn particles that acted as effective nucleation sites for Mg₂Sn, promoting aluminum partitioning and accelerating the precipitation of Mg₁₇Al₁₂ through Al-rich regions. Additionally, Zn and Na co-segregated within the Mg₁₇Al₁₂ phase, reducing misfit strain caused by Zn substitution and improving precipitate stability and refinement. These findings highlight Zn’s critical role, alongside trace Na additions, in refining and accelerating the precipitation of Mg₁₇Al₁₂ and Mg₂Sn phases, thereby enhancing the age-hardening response of magnesium alloys.

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.