Applied-strain-promoted oxidation of Nickel: Insights from ReaxFF molecular dynamic simulation

Ni-based superalloy components are often subjected to applied stress in service. Besides creep and fatigue, the impact of applied stress on metal oxidation corrosion should not be underestimated. In this work, we studied the oxidation behavior of Ni under different applied strains by molecular dynamics simulation with ReaxFF potential. Results show that the oxidation begins with the outward diffusion of random Ni atoms from the surface, and both applied compressive strain and applied tensile strain can activate the Ni surface, advancing the oxidation start time and promoting oxidation. The applied tensile strain promotes oxidation by promoting the inward diffusion of oxygen atoms and inhibiting the outward diffusion of nickel atoms, while the applied compression strain does the opposite. This work provides a better understanding of the effect of mechanical loading on oxidation kinetics, which is helpful for the improvement of anti-corrosion measures of Ni-based superalloys.