A DFT study of structural, elastic and lattice dynamical properties of Fe2Zr and FeZr2 intermetallics

We report plane-wave based density functional theory (DFT) investigation of structural, elastic and lattice dynamical properties of Fe-rich C15-Fe2Zr and Zr-rich FeZr2 intermetallic compounds. These intermetallics dominantly appear in the Fe-Zr alloys which are potential candidates for immobilization of nuclear metallic waste. The calculated elastic constants and phonon dispersions show that both phases are mechanically and dynamically stable. The calculated bulk moduli as a function of temperature show that the Fe-rich C15 phase is less compressible and also less sensitive to temperature than the Zr-rich C16 phase. Furthermore, the C15-Fe2Zr phase has a lower thermal expansion co-efficient but higher thermal conductivity as compared to the C16-FeZr2 phase; while the heat capacities (CP and CV) of both the phases are almost identical above 450 K.