Type 300-series austenitic stainless steel has been widely used as structure materials in current light water reactors and continuing of interest in fusion systems and generation IV reactor designs. The flow localization process is characterized by a severe reduction in uniform elongation under tensile loading conditions following irradiation. Recent work shows that this process can be characterized by a critical stress: necking always occurs at the same value of true stress regardless of the level of irradiation hardening.; Microstructural analysis utilizing scanning electron microscopy (SEM) coupled with electron backscattering diffraction (EBSD) exhibits that for the materials tested at room temperature, there are extensive mechanical twinning bands, which could inhibit the mobility of dislocations thus, improve material's straining hardening and ductility. However, for the material tested at above 200°C, the twinning bands are completely absent. The critical twinning stress is highly dependent on the testing temperatures because of the temperature dependence of stacking fault energy. When the specimen is tested at room temperature, the critical stress is much larger than the critical twinning stress, so the mechanical twinning is activated at that point and fully developed until the onset of necking. However, when the specimen is tested at the elevated temperatures, even the critical stress is smaller than the critical twinning stress which makes the activation of mechanical twinning impossible. The mechanical twinning and dislocation-based planar slip are competing mechanism for the plastic deformation of 316L stainless steel. It is clear that strong textures at Brass and rotation Goss are considerably developed. Macro-texture investigation by XRD combining with the micro-texture examination using EBSD indicate that the underlying controlling mechanism for texture evolution is the dislocation-based planar slip instead of the formation of twinning bands as thought before.; Notch effects have been analyzed utilizing finite element method (FEM) and EBSD misorientation map for unirradiated and irradiated 316L stainless steel. The major issue of interest is the possibility that low ductility, often found following irradiation exposure, will translate into low notch toughness. The influence of irradiation exposure can also lead to flow localization problems with components with notches or stress concentrators.
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