Influence of dynamic strain aging on the deformation behavior during ratcheting of a 316LN stainless steel

Ratcheting behavior of 316LN austenitic stainless steel (SS) was investigated at 823 K as a function of mean stress (σm) and stress amplitude (σa). Test results obtained under different combinations of σm–σa were analyzed in terms of total accumulated strain and cyclic life in order to understand the manifestations of dynamic strain aging (DSA) during ratcheting. The results obtained under specific combinations of σm and σa were correlated with the surface relief, crack density distribution, fracture behavior and substructural changes. Deformation behavior was found to vary with the loading conditions. DSA increased the fatigue life of 316LN SS.