First-Principles Study of Cr₂N/γ-Fe Interface in High Nitrogen Steel

Abstract

The first-principles method was employed to perform the convergence calculations on the Cr₂N and γ-Fe surfaces respectively, which compose the Cr₂N(0001)/γ-Fe(1-11) interface, the stability of Cr₂N(0001) surface was also analyzed, to built OT and HCP stacking sequences with N atom terminated interface models. On this basis, the ideal adhesion work, stability and electronic structure of the Cr₂N/γ-Fe interfaces were calculated, and the formation mechanism of the interfaces in high nitrogen steel was investigated. The result show that the OT stacking interface has a larger ideal adhesion work, and smaller interface energy over the entire range of Cr chemical potentials, which indicate that the interface with OT stacking structure is more stable than the HCP stacking one. From the electronic structure, there is a strong ionic bond between the N and Fe atoms at the interface region in the OT model, and DOS peaks of the same Fe move to the bonding area apparently as well, so that the interface structure is more stable.