First-principles study of interstitial diffusion of oxygen in nickel chromium binary alloy

Abstract

The first-principles calculations of the diffusion processes of oxygen in pure Ni and Ni-Cr binary alloy are conducted to understand the oxidation behavior of nickel base alloys. The cohesive energy, insertion energy of atomic oxygen, and vacancy formation energy in nickel are calculated and compared with experimental data. The activation energies of oxygen are also calculated. The results show agreement with previous work for the oxygen diffusion in pure nickel. However, the calculated activation energy for the diffusion of oxygen in Ni-Cr binary alloy showed lower values than that in nickel because of the limitations of the current calculation model.

First-principles studies on vacancy-modified interstitial diffusion mechanism of oxygen in nickel, associated with large-scale atomic simulation techniques

“…The DFT calculated solution energies are qualitatively consistent with other DFT calculated values from the literature. 14,15 However, the present results are more negative. This is probably a consequence of the present study employing the LDA exchange functional, while the other studies utilizing the GGA functional, as the former generally overestimates the bonding strength while the latter underestimates.…”

“…The energetics of the migration barriers and saddle states predicted using the CI-NEB method for both pathways are shown in Table II, the calculated migration barriers are consistent with the DFT predictions from literature, 14,15 even though there is a small difference of 0.04 $ 0.30 eV. As previously discussed, this difference is primarily due to the different exchange functionals and structural relaxation schemes used in the calculations.…”

“…The literature reports two possible jump pathways. 14,15,30 One is the direct jump from one octahedral site to an adjacent octahedral site (O-O) The other is the jump between the octahedral sites by passing through an adjacent tetrahedral site (O-T-O), as shown in Figure 2.…”

“…Young et al, 13 Megchiche et al, 14 and Kim et al 15 studied oxygen migration barriers in fcc nickel by using the first-principles calculations, and the predicted values are 0.95 6 0.28, 1.12, and 1.23 eV at ground state, respectively, which are far below the range of experimental data. These first-principles calculations indicate that the oxygen diffusion in fcc nickel is via the interstitial mechanism and the minimum energy pathway corresponds to the jump from octahedral interstitial site to an adjacent octahedral site bypassing a co-neighboring tetrahedral site (O-T-O).…”

Multiscale model of metal alloy oxidation at grain boundaries

“…However, due to limitations on the length scales accessible to quantum mechanical simulations, this information is limited to treatment of microscopic processes in isolation, such as transport, 10,11 defect formation, and migration energetics at metal/oxide interface 12 and interfacial potential build up. 13 To access the dynamics of the oxidation processes on the atomistic level, ab initio molecular dynamics (MD) was employed to study very early stages of grain boundary oxidation of binary alloys.…”