Fatigue fracture of duplex stainless steel with heterogeneous nanostructure by heavy cold rolling

Synopsis: Fatigue behaviors of duplex stainless steels with excellent tensile properties brought by heterogeneous nanostructure were examined with changing volume fraction of ferritic-austenitic phases. In as-rolled samples, fatigue strength taken by 10 ⁷ cycles became double comparing with those of conventional stainless steels. The volume fraction of ferritic-austenitic phases has not affected fatigue behavior. Further, the fatigue strength was improved additionally 200 MPa by aging heat-treatment after cold rolling. The duplex stainless steels with heterogeneous nanostructure possessed enough fatigue strength even in 3%NaCl solution though its fatigue strength declined.