Sink effect of grain boundary on radiation-induced segregation in austenitic stainless steel

We have investigated the orientation dependence of grain boundaries in radiation-induced segregation (RIS) in an austenitic stainless steel under irradiation using a high-voltage electron microscope (HVEM) at the Hokkaido University HVEM facility and a new rate equation model for RIS, which incorporates the grain boundary sink strength for point defects. The 〈1 1 0〉 tilt grain boundaries were chosen for the present study. It was observed that, after electron irradiation at a dose rate of 2.0×10−3 dpa s−1 to 10 dpa at temperatures of either 623 or 723 K, RIS was enhanced as the tilt angle increased but was suppressed at coincidence grain boundaries (Σ9 and Σ3). The present result indicates that one needs to explicitly consider the grain boundary sink strength as an important factor affecting radiation-induced grain boundary phenomena (RIGBPH). This work can be thought as a study of the radiation-induced grain boundary phenomena associated with grain boundary engineering related to non-equilibrium phenomena.