Characterisation of nano-scale precipitates in BOR60 irradiated T91 steel using atom probe tomography

摘要

Atom probe tomography has characterised the microstructural changes in T91 steel after BOR60 reactor irradiation at five temperatures between 376 degrees C and 524 degrees C to doses between 14.6 dpa and 35.1 dpa. Irradiation-induced precipitation and segregation to carbide/matrix interface induced by neutron irradiation has been characterised. Atom probe tomography characterisation shows that Mn, Ni, Si-rich (MNS-rich) clusters form in T91 steel irradiated in BOR60 reactor at temperatures between 376 degrees C and 415 degrees C, which is not observed at higher temperatures 460 degrees C and 524 degrees C. The number density, volume fraction and composition of MNS-rich clusters have been characterised. Ni, Mn, Si and P is found to segregate at carbide matrix interface after irradiation at lower temperature and only P segregation is observed at 524 degrees C. (C) 2020 Elsevier B.V. All rights reserved.