Investigation of crack initiation and propagation behavior of AISI 310 stainless steel up to very high cycle fatigue

Fatigue behavior up to very high cycles for AISI 310 stainless steel has been investigated. The fatigue crack initiated from the surface of the material. It was found that up to 106 cycles, cracks initiated from the carbide precipitates at grain boundaries. However, above 106 cycles, the cracks initiated from persistent slip bands found at the surface of the specimen. At lower stress levels, slip bands were developed without initiating the cracks. The horizontal asymptote S–N curve from 106 to 109 cycles was attributed to the development of slip bands all over the surface of the specimen, before crack initiation.