Abstract
Helium bubble formation was observed in austenitic stainless steels by transmission electron microscopy following implantation of 30 to 1000 appm helium at room temperature and annealing at 700 to 800°C. Helium bubble distributions at dislocations and at various grain boundaries and precipitates were studied. It was found that interfacial dislocations play a dominant role in bubble nucleation at grain and interphase boundaries but not at Tic-matrix interfaces. Particularly high trapping of helium was observed at Tic precipitate-matrix interfaces which is attributed to an inhomogeneous ripening mechanism.