The generalized planar fault energy, ductility, and twinnability of Al and Al—RE (RE = Sc, Y, Dy, Tb, Nd) at different temperatures: A first-principles study

The genearlized planar fault energies of Al and Al—RE (RE = Sc, Y, Dy, Tb, Nd) alloys have been investigated using first-principles methods combined with a quasiharmonic approach. The stacking fault energies, unstable stacking fault energies, and unstable twinning energies decrease slightly with increasing temperature. The ductility parameter D, the relative barrier difference δutus, and the twinnability τa of Al and Al—RE alloys at different temperatures have been determined. It is found that the ductilities of Al and Al alloys are nearly the same and the ductilities increase slightly with increasing temperature. The RE alloying elements make twinning more likely and the twinnabilities of Al and Al alloys decrease with increasing temperature.