Evolution with temperature of point defects concentration in Fe2ZrX ( X=V, Y, Tc, Ru ): DFT and Wagner-Schottky modeling

Abstract

The evolution with temperature of the point defect concentration in the
cubic C15-ZrFe 2 Laves phase was investigated in the presence of several
ternary additions X (X=V, Y, Tc, Ru). The heats of formation of the
different point defects were carried out at 0K by means of DFT
calculations. The Wagner-Schottky Model, based on substitutional and
interstitial sublattices configuration within the canonical ensemble, was
applied to investigate temperature effects on the defect concentration. The
main results show a strong dependency of the C15-Fe 2 Zr stability on the
point defect type. Energetically, the Ru Fe antisite is the most stable defect
at low temperatures (0 K), whereas the Va Fe , Va Zr , and Y Fe are the least
stable ones. At finite temperatures, it was found that antisites are the
dominant constitutional defects on both sides of stoichiometry in the C15-
ZrFe 2 compound.