Development of understanding of the interaction between localizeddeformation and SCC of austenitic stainless steels exposed to primaryPWR environment

摘要

Understanding and quantification of interactions between localized deformation inrnmaterials and environmental-assisted cracking (EAC) could play an important role inrnmaintaining the integrity of LWR components. Thus, a detailed understanding ofrnstrain localization during plastic deformation and of the underlying mechanisms is ofrngreat importance for the manufacturing and design of materials exposed to thernenvironment of the primary circuit of PWRs. Thus, the crystal plasticity law of a 304Lrnaustenitic stainless steel has been identified, in order to quantify the effect of arnchange of strain path on the strain localization and increase the understanding of therncontribution of the strain hardening and the strain incompatibilities on thernmechanisms of initiation of SCC. Pre-deformation of the specimens used for SCCrntests was evaluated using image correlation. Constant elongation rate tests andrnconstant elongation tests were conducted for different levels of pre-deformationsrn(0.07 < ε < 0.18). First examinations indicated the severe and deleterious effect of thernstrain localization due to a change of strain path on intergranular SCC susceptibility.rnIntergranular cracks initiated systematically in the low-deformed areas, where limitedrndeformation (less than 1%) occurred during the exposure to the environment, andrnwhere high stress levels due to strain incompatibilities are expected.