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

We have investigated the orientation dependence of grain boundaries in radi ation-induced segregation (RIS) in an austenitic stainless steel under irra diation using a high-voltage electron microscope (HVEM) at the Hokkaido Uni versity HVEM facility and a new rate equation model for RIS, which incorpor ates the grain boundary sink strength for point defects. The [110] tilt gra in boundaries were chosen for the present study. It was observed that, afte r electron irradiation at a dose rate of 2.0 x 10(-3) dpa s(-1) to 10 dpa a t temperatures of either 623 or 723 K, RIS was enhanced as the tilt angle i ncreased but was suppressed at coincidence grain boundaries (Sigma9 and Sig ma3). The present result indicates that one needs to explicitly consider th e grain boundary sink strength as an important factor affecting radiation-i nduced grain boundary phenomena (RIGBPH). This work can be thought as a stu dy of the radiation-induced grain boundary phenomena associated with grain boundary engineering related to non-equilibrium phenomena. (C) 2000 Elsevie r Science B.V. All rights reserved.