A micromechanical analysis of swelling-induced embrittlement in neutron-irradiated austenitic stainless steels

Swelling is commonly observed in austenitic stainless steels irradiated at high doses and temperatures, such as fuel claddings Fast-Breeder Reactors (FBR), a consequence of the formation irradiation-induced nanovoids. Macroscopic embrittlement has been reported above critical swelling level. Several physical explanations have proposed void-related fracture mechanisms phase transformation associated with local changes microchemistry. In addition, structural effects can affect level, tentatively explained by corrosion, gradient bending effects. order to address these phenomena, an extended experimental database first presented, based on pins Phénix fast reactor, showing evolution conventional tensile properties swelling. present database, 15-15Ti specimens were from 30 120 dpa, irradiation temperatures ranging 400 °C 625 maximum 11%. Other data published scientific literature also included analysis extend range up 30%. SEM TEM are summarized highlight specific related presence voids. Theoretical finite element simulations then performed porous materials constitutive equations rationalize observations. Analytical numerical results show that swelling-induced be understood mechanical perspective transition void growth coalescence deformation mode. The effect spatial heterogeneity distribution quantified shown key parameter. Structural coming tests ring axial cladding thickness quantified. Numerical compared data, good agreement observed.