Thermodynamic and Vibrational Analysis of Binary and Ternary Fe-Al-Ni Alloys Based on the Miedema Model

Abstract

In the present article, theoretically and semi-empirically, the thermodynamic and vibrational character of Fe-Al, Fe-Ni, and Al-Ni binary alloys, as well as the ternary Fe-Al-Ni system are studied. Formation enthalpy values are calculated over a wide range of compositions following the Miedema model for determining the alloying tendency and thermodynamic stability. Simulated FTIR spectra are utilized to further gain complementary information about the bonding environment of the alloy system by characterizing typical vibrational modes of hydroxyl species and metal–oxygen bonds. The performance of aluminum-containing compositions is strongly negatively tented on the formation enthalpy and thus is highly thermodynamically stable whereas Fe-Ni-rich regions display weaker energetic stabilization. The significant vibrational properties demonstrated by FTIR analysis are in agreement with the strong chemical interactions determined from thermodynamic calculations. Together, these results indicate that the synthesis of the thermodynamic and vibrational analysis leads to a consistent characterization of the stability and bonding properties of Fe-Al-Ni alloys and a basis for alloy design.