First-principles studies of ternary site occupancy in the C15 NbCr2 Laves phase

The full-potential linearized augmented plane-wave method within the generalized gradient approximation has been employed to study the site occupancy behaviors of ternary additions, such as Ti, V, Zr, Mo and W, in the C15 NbCr2 Laves phase. The calculated results of the site occupancy energy show that V and Mo preferentially occupy the Cr sites, and W has a weak site preference for the Cr sites in NbCr2. Ti and Zr preferentially substitute the Nb sites in NbCr2. Calculations of the heat of formation show that occupancy of V on the Cr sites and of Ti and Zr on the Nb sites stabilizes the NbCr2 Laves phase. The site occupancy behaviors of those ternary additions in NbCr2 are discussed together with the calculated electronic structure of the ternary Laves phases.