008

the mechanical removal of the corroded surface layer and the respective values of the reference material. However, the persistent, dramatically low values for tensile ductility prove the occurrence of a volumetric phenomenon that cannot be related to surface oxidation processes. The results of present investigation in conjunction with the results in [60, 75], provide evidence that the determined dramatic embrittlement of the investigated alloys is caused by hydrogen absorption in the material during the corrosion processes. Present-day tests for evaluating corrosion resistance of aircraft structure aluminum alloys do not account for this important aspect.

9.6.3.3 Fatigue Behavior of Corroded Specimens

S-N Curves Following Exfoliation Corrosion Displayed in Fig. 9.23 are S-N curves derived for the material 2024 alloy (anodized and sealed) following exposure to exfoliation corrosion solution for 36 h for specimens without a hole (Kt = 1) or including a hole (Kt = 2.5). For comparison the S-N curves of the uncorroded alloys with and without anodizing and sealing are included as well.

Ultimate Stress

3 Yield Stress

Elongation to failure

1 Energy density

Ultimate Stress

Reference

Exfoliation Corrosion (48 h)

Exfoliation Corrosion (72 h)

0 0

Post a comment