Reactive molecular dynamics study on interfacial reaction behavior of Fe-Cr-Ni alloy

The present study employed reactive molecular dynamics (ReaxFF-MD) simulations to explore the oxidation behavior of Fe-Cr-Ni alloys in alkaline solution, with a focus on critical challenges in enhancing the durability of steel reinforcements for concrete structures exposed to extreme environments. By investigating the influences and mechanisms of external electric field, temperature, and nickel content on the oxidation process, this work provides atomic-scale insights into the corrosion behavior of Fe-Cr-Ni alloys. The results indicate that both higher external electric fields and increased temperature notably accelerate the oxidation reaction, resulting in the formation of a thicker and more stable oxide layer. Conversely, an increase in nickel content acts to suppress the oxidation reaction. Alloys with lower nickel content exhibit more pronounced oxidation and develop thicker oxide layers, whereas alloys with higher nickel content form thinner but denser oxide layers. Within the oxidation process, Fe, Cr, and Ni each fulfill distinct roles. The high oxidation activity of Cr makes it the dominant element in the formation of the oxide film, while Ni stabilizes the oxide layer through its passivation effect. Through this study also provides theoretical insights for optimizing alloy design to extend their service life in aggressive industrial environments.