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 plastic strain amplitudes. Three domains on the cyclic stress-strain curve were found. In the middle domain the plateau behaviour corresponds to fatigue softening. The domain at low plastic strain amplitudes is characterized by stabilized behaviour and the domain of the highest plastic strain amplitudes by continuous hardening. Individual domains were correlated with observed dislocation structures. The existence of the plateau can be related to the localization of the cyclic strain into persistent slip bands. A Manson-Coffin plot of the material over a wide cyclic amplitude range is curved and can be approximated by a double logarithmic dependence.