Thus, coupled with metallography, the results of the electrochemical measurements indicate
that:
The cracks run a clearly intergranular course (Fig. 5), preferentially along the δ-ferrite /
martensite boundaries, with occasional jerks along the martensite / martensite boundary.
This has been confirmed by fractographic analysis of the denuded surfaces of the cracks
(Fig. 6).
Fatigue cracks can initiate in locations sensitized to and damaged by intergranular corrosion
(Fig. 7).
In repeated potentiodynamic measurements conducted on the same surfaces after prudent
polishing, this negative effect i.e. sensitization due to overheating, falls off gradually, due to the
removal of the original (most affected) surface layer.