First-principles study of stacking fault energies in Mg-based binary alloys

The stable stacking fault energies for basal stacking faults I1 in various categories of Mg-based binary alloys have been studied using density functional theory. Two concentrations of alloying atoms, 11 and 25 at.% at the stacking fault interface, were considered in the computations, by constructing different supercells after strict test of energy convergence against the sizes and shapes of the supercells. It has been shown that the stacking fault energy of Mg varies in a broad range with alloying elements. While the influence on the stacking fault energy becomes stronger with the increase of solute concentration for majority of the alloying elements, some elements show an opposite tendency. The effects of solute atoms and their concentrations on stacking fault energy were discussed in view of ionization energy, atomic radius and quantum tunneling effect.