Misorientation dependence of grain boundary segregation under electron irradiation in an austenitic stainless steel

The effect of grain boundary misorientation on intergranular Radiation-Induced Segregation (RIS) in an Fe-15Cr-20Ni alloy was studied using a high voltage electron microscope (HVEM) at Hokkaido University HVEM facility and a rate equation model for RIS which incorporated grain boundary sink strength. The < 110 > tilt grain boundaries were chosen for the present study. It was observed that after electron irradiation with 3x10(-3) dpa/s to 3 dpa at both temperatures of 623 K and 723 K, RIS was enhanced as the tilt angle increases but was suppressed at coincidence grain boundaries (Sigma 9 and Sigma 3). The present result indicates that one needs explicitly to consider the grain boundary sink strength for point defects as an important factor affecting radiation induced grain boundary phenomena.