Cyclic response of superduplex stainless steels in seawater

Superduplex stainless steels (SDSSs) are increasingly used in corrosive environments such as seawater. Hence, knowledge about their fatigue response in this medium is essential for reliable design because corrosion-fatigue is an important cause of material damage. The aim of this work is to compare the low cycle fatigue (LCF) behaviour of a SDSS in air and in artificial seawater. Two relatively high values of plastic strain amplitude were selected in order to perform the LCF tests and compare the number of cycles to reach failure in both air and seawater. The experimental results show a remarkable reduction in fatigue life in presence of the aqueous solution. This is associated with enhanced strain localisation and easier microcrack nucleation in the corrosive environment.