The structural stabilities of Al3(Sc1−xMx) by first-principles calculations

The positive effects of Al3Sc phase on Al–Sc alloys can be promoted by adding to the third elements. The structure properties of Al3Sc when it dissolves the third elements are investigated by first-principles calculations. Special quasirandom structures are developed for the quasi-binary L12 structures. The calculations indicate that the elements of Ti, Zr, Y and Ta tend to substitute for Sc in Al3Sc, while Ni and Si prefer to substitute for Al. The present lattice parameters generally follow the Vegard’s law. The high solubility of Ti and Y in Al3Sc is revealed in the calculated quasi-binary phase diagram.