A First-principles Study On Generalized Stacking-fault Energies Of Magnesium-based Binary Alloys

Magnesium alloys are widely applied in electronic communications,aerospace,and automotive industries due to its low density,high specific strength and high specific stiffness.On the other hand,the insufficient independent slip systems in the deformation mechanisms of Mg with hexagonal close-packed structure lead to the poor ductility properties,which limits the applications of Mg alloys.Study on plastic deformation mechanisms of Mg alloys in order to seek appropriate methods to optimize the ductility properties of Mg alloys,has become a hot topic in materials research field.Elemental doping is an effective way to change the structures of Mg alloys,as well as the activation energy of the slip systems in Mg alloys,and then improve the ductility properties of Mg alloys.So far,few types of doping elements have been involved in the calculations on ductility of Mg alloys.Among the past work on first-principles calculations on generalized stacking-fault energies of Mg alloys,there was no complete system established for the selection of stacking faults,the constructions of stacking fault models and the computational methods.In this project,we selected 43 types of common metal elements for the doping of Mg alloys,and calculated the generalized stacking-fault energies of all the doped Mg alloying systems.The influence relationships between doping elements and generalized stacking-fault energies of Mg-based binary alloys has been studied through the analysis of properties of doping elements and the corresponding doping systems.We have also built a prediction model to predict the generalized stacking-fault energies of Mg alloys with the basic information of doping elements.The prediction model gives a good fitness between the predicted values and DFT-calculated values of generalized stacking-fault energies in Mg alloys,and this model could be beneficial to predict the ductility properties of new Mg alloys as well as to offer instructions for the composition design of Mg alloys on the purpose of improving ductility.