CONICET | Buscador de Institutos y Recursos Humanos

In the Framework of an extensive investigation the correlation between the lowcycle fatigue behavior and microstructure of duplex stainless steel has been studied. The cyclic behavior has been analyzed through the cyclic flow stress components, i.e. the effective and the internal ones, regarding crack initiation and propagation. The importance of the microstructural studies, has allowed to understand the mechanisms of deformation and the role of the nitrogen in the fatigue resistance of the studied steels. The analysis of the effective stress has shown that the interaction between nitrogen atoms and dislocations can be explained through a model for weak obstacles. On the other hand, the dislocations structure has been analyzed in connection with the fatigue surface damage. Also, the mechanisms that intervene in the formation of fatigue microcracks were studied. The study of cyclic behavior was carried out in two duplex stainless steel with different nitrogen content and different proportion of alpha-gamma phases. The tests were conducted at room temperature under fully reversed total strain control. The surface damage was observed by optical and electronic microscopy and analysed in relation to underlyning dislocation structure by transmission electron microscopy. conducted at room temperature under fully reversed total strain control. The surface damage was observed by optical and electronic microscopy and analysed in relation to underlyning dislocation structure by transmission electron microscopy. -g phases. The tests were conducted at room temperature under fully reversed total strain control. The surface damage was observed by optical and electronic microscopy and analysed in relation to underlyning dislocation structure by transmission electron microscopy.