ROLE OF SLIP BEHAVIOR IN THE IRRADIATION ASSISTED STRESS CORROSION CRACKING IN AUSTENTTIC STEELS

摘要

Irradiation assisted stress corrosion cracking appears to be linked to the localization of slip into dislocation channels. Three austenitic steels with varying degrees of cracking susceptibility were irradiated with 2 MeV protons at 360°C to 5 dpa and strained in 288°C simulated BWR conditions. Deformation behavior was characterized by Schmid factors, resolved shear stresses, slip continuity across grain boundaries, and the angle between dislocation channels and the cracked boundaries. Cracking susceptibility was found to correlate with the dislocation channel properties, such as the resolved shear stress and slip continuity at grain boundaries. Higher cracking susceptibility was found at grain boundaries perpendicular to the tensile axis and adjacent to low Schmid factor grains, which have high normal stresses acting on the boundary. Localized deformation and high normal stress have significant roles in IASCC, though they do not fully describe cracking susceptibility.