Solubility of zirconium and silicon in molybdenum studied by first-principles calculations

We investigate the solubility of zirconium and silicon in molybdenum using a supercell approach within the framework of electronic density-functional theory. The heat of solution is calculated for various supercells and an extrapolation procedure is applied to correct for finite-size effects. An analysis of size (lattice distortion) and chemical (bond strength) contributions to the heat of solution is applied to explain different solubility limits of Zr and Si. The charge redistribution around substitutionals is quantitatively estimated using a Bader charge analysis.