Cyclic Deformation Behavior of a 316L Austenitic Stainless Steel Processed by High Pressure Torsion

The influence of severe plastic deformation (SPD) on the fatigue behavior of a modified 316L austenitic stainless steel is investigated. Different ultrafine‐grained and nanocrystalline microstructures are obtained by changing the processing parameters and applying a post heat treatment procedure. Samples are fatigued using both, load and strain controlled experiments. High pressure torsion processing makes it possible to reach a saturation microstructure, which is cyclically stable up to a stress level three times higher than the stress level of the coarse‐grained structure. Fracture surface investigations and surface damage clearly show that the failure behavior of the SPD states under cyclic loading is different to their coarse‐grained counterparts. For these microstructures, localized deformation in shear bands seems to play a major role for crack initiation and propagation.