Nuclear Materials and Energy (Dec 2020)
Helium effect on the sink strength of grain boundaries in F82H
Abstract
F82H were irradiated by Kr2+ ions with and without helium up to 1 displacement per atom at 500 °C, and cavity distribution around grain boundary was investigated by transmission electron microscopy. In F82H irradiated by Kr2+ ions, the cavity number density and the cavity size tended to be decreased and increased as a function of the distance from grain boundary, respectively. This gradient of cavity distribution seemed to be depending on the character of grain boundary. While, the size distribution of cavity seemed to be homogeneous in F82H irradiated by Kr2++He+ ions. This indicates that even prior austenite grain boundary hardly acts as sinks for vacancies if a high number density of helium atoms exists, which is probably due to the decrease in vacancy mobility by helium trapping.
