关键词: 腐蚀缺陷, 力学-电化学耦合模型, 腐蚀电场, 弹性变形, 塑性变形

Abstract: The current research on ship corrosion electric field has not taken into account the aggravation of corrosion caused by stress and strain in service surroundings. Using the mechanical-electrochemical coupling model of metal/solution, theoretical expressions of the effects of corrosion defect depth and defect width on the stress distribution, corrosion potential, current density, and corrosion electric field of 921A steel shell and solution are obtained under stress-strain conditions, and the coupling model is simulated using COMSOL Multiphysics. The results show that the stress concentration at the corrosion defect is more evident when the defect depth is greater or the defect width is smaller. The potential difference in solution increases with the defect depth; the corrosion potential at the metal/solution interface decreases sharply with the increase of the defect depth; the corrosion potential decreases slightly with the decrease in the defect width. The influence of defect depth on anode current density, cathode current density, and net current density exceeds that of defect width. Both ends of the defect have a negative net current density. The electric field modulus increases with the defect depth and decreases with the defect width.

Key words: corrosiondefect, mechanical-electrochemicalcouplingmodel, corrosionelectricfield, elasticdeformation, plasticdeformation