Segregation behavior of alloying elements at the fcc-Fe/TiC interface by first principles exploration

Abstract

In this paper, the effects of rare earth elements on the bonding strength and stability of TiC/fcc-Fe interface are explored by using the first-principles method based on density functional theory. The results show that the Ti terminal is more stable than the C terminal in the process of forming the interface. The alloying elements tend to segregate at position 2 on the side of fcc-Fe. The segregation of Mo, Nb, Cr and Ce alloying elements increases the interatomic electron cloud enrichment and consumption between the interfaces and enhances the Fe–Ti interactions. The d orbitals of Mo, Nb, Cr and Ce and f orbitals of Ce have strong hybridization with Fe-d orbitals and Ti-d orbitals electrons near the Fermi energy level, indicating an increase in bonding strength and stability of the interfaces. When Fe atoms are replaced by W, Ni and Al atoms, the covalent bond strength between interfacial atoms is reduced, thus weakening the interfacial bonding strength. This provides solid theoretical foundation with regard to further application in austenitic heat-resistant steel fields.