Influence of alloying elements on phase stability and elastic properties of aluminum and magnesium studied by first principles

Influence mechanisms of alloying elements Al, Mg, Ti, V, Cr, Fe, Ni, Cu, Zr, Nb, Mo, Sn, Ta, and W on phase stability and elastic properties of magnesium and aluminum were studied by first principles total energy calculations. Calculations show that all systems with impurity satisfy the mechanical stability criteria. However, only Sn could enhance the stability of Mg, but decreases the stability of Al energetically. Mg and Cr also show the same effect as Sn on Al. The electronic structure analysis illustrates that an extra bonding peak appears in the low energy region in Mg-Sn, which increases the stability of Mg. While other alloying elements slightly move the Fermi energy level toward the conduction band causing a decrease on stability of Mg. In Al with impurity systems, the alloying elements except Sn, Mg, and Cr greatly increase the number of bonding peaks in low energy regions and consequently increase the stability of the systems.