Silvina Hereñú, Iris Alvarez-Armas, Alberto Armas, Suzanne Degallaix, Adriana Condó, Francisco Lovey, S. C. de Bariloche
May 28, 2013
Low cycle fatigue of SAF 2507 duplex stainless steel has been studied at different temperatures in two thermal conditions: unaged (as-received) and aged (100 hours at 475°C). The corresponding cyclic flow stress components, the friction, σ F , and the back stresses, σ B , have been analyzed in relation to the observed microstructure. σ F attains higher values at room temperature than in the intermediate range of temperatures in both thermal conditions due to the influence of the lattice friction stress on screw dislocations in the ferrite phase. The cyclic softening observed at all temperatures in aged samples is caused by the decrease of the back stress σ B . The increase of σ B in unaged samples at 300°C is consistent with the high dislocation density observed in the ferrite phase ascribed as a typical manifestation of dynamic strain aging.