PSI - Issue 68

Louka Eleftheria-Sotiria et al. / Procedia Structural Integrity 68 (2025) 894–900 Louka Eleftheria-Sotiria et al. / Structural Integrity Procedia 00 (2025) 000–000

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For the T3 temper (Fig. 6a) the maximum axial nominal strain value was reduced from 17.3 % to approximately 10 % after the 24 h EXCO exposure. A significant decrease in the mechanical strength properties R p0.2% and R m was observed. The calculated values were in good agreement with the experiment regarding the total elongation values with the model, while it seems that the model slightly underestimates the mechanical strength properties. For the T8 temper (Fig. 6b) a lower decrease of axial nominal strain was observed as compared to T3. The calculated values were again in good agreement with the experimental regarding the uniform elongation and strength properties.

Fig. 5. Comparison between tensile test experiments and calculations for 2 h EXCO exposure for (a) 2198-T3; (b) 2198-T8.

Fig. 6. Comparison between tensile test experiments and calculations for 24 h EXCO exposure for (a) 2198-T3; (b) 2198-T8.

6. Conclusions A comprehensive experimental and numerical study was conducted on the effect of corrosion attack on the mechanical behaviour of AA2198 for two different ageing tempers (T3 and T8). The results of the study reveal that the surface corrosion morphology in T3 was found to be more localized, while in T8 more uniformly distributed pits were noticed throughout the specimen's surface. A higher decrease in axial nominal strain is noticed for T3 temper due to increasing EXCO exposure, while a more sudden drop of the tensile strength properties was evident in T8 with increasing EXCO exposure. The results so far suggest that the model can predict with good accuracy the mechanical behaviour of the corroded specimen. It was found that the randomness of the distribution of corrosion damage can affect slightly the predicted stress-strain curve but more significantly the predicted fracture strain. This is mainly affected by the proximity of corrosion pits, and, for the tested materials, it was found to be approximately ± 0.5%.