In situ observation of the effect of stress on A533B model alloy Fe-1.4Mn under electron irradiation

PWR type nuclear reactor pressure vessels are neutron irradiated with stress during reactor operation. Therefore, it is important to know the effect of irradiation embrittlement of the material with and without stress conditions. It is already known that radiation hardening of the materials controlled by dislocation density in many materials. In the pressure vessel steels and model alloys, dislocation loop density is very sensitive to solutes (namely, Mn, Ni, Si etc.) levels containing in the alloy. Formation of small dislocation loops is prominent without applied stress in the matrix and also in the vicinity of dislocation in Mn containing alloys. These dislocation loops were identified as interstitial type dislocation loops. In this study, Microstructure evolution of Fe-1.4 mass% Mn alloy was studied in high voltage electron microscope (HVEM) by using a tensile sample holder. With stress condition, I-loop density was suppressed. But growth of I-loop becomes prominent.