CYCLIC PLASTICITY IN TYPE 316L AUSTENITIC STAINLESS-STEEL

The cyclic stress-strain response of two heats of austenitic stainless steel 316L was experimentally studied under a wide range of cyclic pl astic strain amplitudes. Three domains on the cyclic stress-strain cur ve were found. In the middle domain the plateau behaviour corresponds to fatigue softening. The domain at low plastic strain amplitudes is c haracterized by stabilized behaviour and the domain of the highest pla stic strain amplitudes by continuous hardening. Individual domains wer e correlated with observed dislocation structures. The existence of th e plateau can be related to the localization of the cyclic strain into persistent slip bands. A Manson-Coffin plot of the material over a wi de cyclic amplitude range is curved and can be approximated by a doubl e logarithmic dependence.