Fig. 5 The outset of the corrosion crack found on the blade base. Vilella-Bain etchant, magnif. 500.
Fig. 6 Denuded surface of corrosion crack on the blade base. In the lower part of the picture, intact blade surface. SEM, magnif. 1000.
Fig. 7 Starting point of propagation of a fatigue crack on the facettes affected by intergranular corrosion. SEM, magnif. 1000