Theoretical Prediction of Ternary Site Occupancies in ZrCr2 and NbCr2 Laves Phases

Site occupancies of ternary additions (Ti, V, and W) in the C15 ZrCr2 and NbCr2 Laves phases were predicted theoretically by first-principles calculations based on density functional theory. The results suggest that Ti preferentially occupies the Zr and Nb sites in ZrCr2 and NbCr2, respectively. V and W substitute the Cr sites in both ZrCr2 and NbCr2. The calculations of heats of formation also show that the occupancy of W on the Cr sites and of Ti on the Zr sites stabilize ZrCr2. For NbCr2, the occupancy of V on the Cr sites and of Ti on the Nb sites increases the phase stability.