Stabilities, electronic and elastic properties of L12-Al3(Sc1-x,Zrx) with different Zr content: A first-principles study

First-principles method was performed to investigate the stabilities, electronic structures and elastic properties of L12-Al3(Sc1-xZrx) with different Zr content, and the optimized structural parameters were consistent with previous literature. The obtained negative values of both formation and mixing enthalpies suggested all the L12-Al3(Sc1-xZrx) possessed structural stabilities. As Zr atoms replaced for Sc in L12-Al3(Sc1-xZrx) structure, the interactions between Zr-d state as well as Al-p and (Sc,Zr)-d were promoted, and not only the covalent bonding strength was enhanced, but also its bonding characteristics on (100) and (110) planes tended to be consistent. The bulk modulus, shear modulus, Young's modulus, Poisson's ratio and elastic anisotropy of these phases were also derived from the calculated elastic constants. It is found that for L12-Al3(Sc1-xZrx) that had high substitution of Zr atoms, the volume changing resistance was promoted with the resistance to reversible deformations being subdued. Besides, the ductility was enhanced for the increase of B/G ratio and Cauchy pressure value (C12-C44).