Effect of temperature-induced solute distribution on stacking fault energy in Mg-X(X = Li, Cu, Zn, Al, Y and Zr) solid solution: a first-principles study

Stacking fault energies (SFEs) of Mg solid solutions at different temperatures are very significant for studying dissociation of dislocation, plasticity deformation and other mechanical properties. Our present work starts with the investigation of interactions between basal stacking faults (SFs) and solutes (Li, Cu, Zn, Al, Y and Zr) using first-principles calculations. It is found that the interactions between basal SFs and solutes can be extended to several closed-packed layers. Combined with Fermi-Dirac function of solute distribution at each layer, the temperature dependence of SFE for Mg-X(X = Li, Cu, Zn, Al, Y and Zr) solid solution has been investigated. This study predicts correctly the increase tendency observed in experiment. Then the SFEs of Mg solid solutions at room temperature of 300 K are investigated at different solute concentrations; the obtained concentration dependence of SFEs is in agreement with the available experimental values. So the solute distribution under finite temperature due to the basal SF-solute interactions plays a critical role in the variation of SFEs of Mg solid solutions.