Influence of passivation film on stress corrosion of 304 stainless steel crack tip
A two-dimensional numerical model incorporating material diffusion and solid mechanics was established.In this model,it was assumed that the Fe3O4 protective film was formed by oxygen diffusion in the metal according to Fick's law,and the film-induced stress was calculated with hygroscopic expansion method.The model can simulate the formation of the passivation film and film-induced stress at crack tip.Based on this model,the finite element model of the plate specimen with a unilateral crack was created by COMSOL to investi-gate the influence of passivation on stress,equivalent plastic strain and crack propagation at crack tip under applied displacement loads,and the stress distribution when the oxide film re-fractures.The results show that the passivation film weakens the stress corrosion of crack tip to some extent and reduces the possibility of crack extension.In the initial stage of the crack expansion,the passivation film weakens the stress of crack tip,and when the crack extension is longer,the passivation film has basically no effect on the crack tip.
万方数据
维普
