Revealing pitting corrosion evolution at atomic scale with a hybrid scheme

Pitting corrosion is an insidious process that can cause catastrophic failure of structural materials unexpectedly. Understanding the mechanism is crucial but also challenging due to the absence of detailed atomic-scale processes resulting from the limited spatial and/or temporal resolution best achieved in extensive experimental and computational efforts. Here, using a hybrid Monte Carlo/molecular statics scheme validated by experiments, we revealed the detailed corrosion process of four lattice planes of a single-crystal aluminum at the atomic level. The detailed evolution, affected by corrosion energy, temperature, and lattice planes, demonstrates that the sudden onset and abrupt growth of pitting corrosion, the corrosion pattern formed on lattice planes, and the corrosion resistance of these planes can all be explained in terms of the energy of the surface atoms and how the neighboring atoms are affected after some atoms are corroded. By providing sufficient information with the highest resolution to date, this hybrid scheme can assist in understanding the corrosion mechanisms of pure metals under various conditions and aids in designing corrosion-resistant materials.