An atomic insight into role of temperature and stress on acidic corrosion behaviour and mechanical property of polycrystalline Fe-based alloys

ZXY Wang and J Li and SH Xing and B Liu and Y Zhang and QH Fang, SURFACES AND INTERFACES, 70, 106799 (2025).

DOI: 10.1016/j.surfin.2025.106799

Fe-based alloys have great potential for applications in the aerospace and nuclear industries due to suitable strength and ductility, and high corrosion resistance. However, the acidic corrosion behaviour of polycrystalline Fe-based alloys has not been resolved at atomic scale. In this work, we investigate the acidic corrosion behaviour and mechanical property in nanocrystalline Fe-based alloys, with a focus on the influence of temperature and stress using reactive molecular dynamics (MD) simulations. Deep-sea corrosion experiments are conducted on low-alloy steel to investigate the effect of stress on the corrosion behavior. The results show that the corrosion process exhibits distinct stages and ultimately reaches a state of dynamic equilibrium involving the destruction and regeneration of a passivation film. The corrosion rate at grain boundaries is higher than that within the grains. Additionally, an increase in temperature promotes the rate of metal dissolution, diffusion, and corrosion reactions. The high stress exacerbates corrosion and leads to the formation of more complex corrosion products. The large deformation inhibits the worsening of corrosion. More importantly, corrosion has a significant impact on the yield strength and elastic modulus of Fe-based alloys, reducing their mechanical properties, especially at the elevated temperatures. Deep-sea corrosion experiments reveal the increasing pressure reduces both corrosion rate and pitting depth, while promoting more numerous but shallower pits at higher stresses. The corrosion products align with simulation results, though structural disorder weakens protective capacity. This work affords an atomic insight into the acidic corrosion behaviour and its mechanism origin, which can deepen the fundamental understanding in corrosion processes at the atomic level.

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