Fatigue Crack Propagation by Channel Fracture in Irradiated 316 Stainless Steel

Abstract

Fatigue crack growth rates (da/dN)in an irradiated cold worked 316 stainless steel were obtained at temperatures of 298, 573 and 673 K. Specimens were prepared from a duct material, which irradiated at 683 K to 20 displacements per atom in an experimental fast breeder reactor. Fatigue loading caused channel fracture to occur in the irradiated material. This was accompanied by acceleration of da/dN. Both the increment of da/dN and the fraction of channel fracture in fracture surface became larger with stress intensity factor range at temperatures of 573 and 673 K, but they were not at 298 K. Results indicate that irradiation induced channel fracture increased da/dN.

Irradiation effects on reduced activation ferritic/martensitic steels—tensile, impact, fatigue properties and modelling

“…This reduction was accompanied by the change in fracture surface: the feature indicates that a fatigue crack was propagated with a channel fracture like mechanism, suggesting an important role of dislocation channeling in small strain ranges [26]. Similar results have been obtained for irradiation hardened austenitic alloys [49][50][51][52]. Channel deformation to fracture occurred by a characteristic dislocation microstructure in deformed metals and alloys after irradiation [35].…”