A micromechanical analysis of intergranular stress corrosion cracking of an irradiated austenitic stainless steel

Irradiation Assisted Stress Corrosion Cracking (IASCC) is a material degradation phenomenon affecting austenitic stainless steels used in nuclear Pressurized Water Reactors (PWR), leading to the initiation and propagation of intergranular cracks. Such belongs broader class InterGranular (IGSCC). A micromechanical analysis IGSCC an irradiated steel performed this study assess local cracking conditions. 304L proton sample tested PWR environment showing investigated. Serial sectioning, Electron BackScatter Diffraction (EBSD) two-step misalignment procedure are reconstruct 3D microstructure over extended volume, statistically criteria. methodology also developed compute Grain Boundary (GB) normal orientations based on EBSD measurements. The statistical shows that occurs preferentially for GB normals aligned with mechanical loading axis, but low values Luster-Morris slip transmission parameter. Micromechanical simulations reconstructed microstructure, FFT-based solver crystal plasticity constitutive equations modified account at grain boundaries finally performed. These rationalize correlation obtained experimentally into single stress-based criterion. actual strengths weaknesses such approach discussed.