金属腐蚀的多尺度计算模拟研究进展

The application and progress of calculation and simulation in the field of metal corrosion are summarized in this paper, which provide a cross-scale method combined with first-principles and finite element calculation to investigate the behavior and mechanism of Al and its alloys. We have carried out the calculations of the adsorption of O₂ and H₂O on Al surface to study the forming mechanism of passive film. The pitting initiation was studied by the interaction between Cl^- and passive film using first-principles calculations, which was proved that the pitting initiation tended to Cl^- adsorption induced oxide thinning. The adsorption, solution and diffusion of H atom was performed along Al (111) surface to obtain the most stable adsorption and solution site and the diffusion energy barrier. A grain boundary (GB) and grain models were constructed to characterize the solution and diffusion of H atom. The strength of GB characterized by its cohesive energy was calculated by first-principles method, which decreased with the increasing H concentration segregated in GB. The cohesive energies were input into cohesive finite element calculations as the fracture energies to simulate the intergranular cracking, which was a cross-scale study. The application of the cross-scale approach is very efficient for investigating the evolution of hydrogen induced intergranular cracking. The work of this study provides a scheme using a cross-scale calculation from atomic scale to macro-scale to study the atmospheric corrosion behavior and mechanism of metals.