Mechanical properties and microstructure of advanced ferritic-martensitic steels used under high dose neutron irradiation

Some results of the study of mechanical properties and structure of ferriti c-martensitic chromium steels with 13% and 9% chromium, irradiated in the B OR-60 reactor up to different damage doses are presented in this report. Re sults concerning the behaviour of commercial steels, containing to molybden um, vanadium and niobium, and developed for the use in fusion reactors, are compared to low-activation steels in which W and Ta replaced Mo and Nb. It is shown that after irradiation to the dose of similar to 10 dpa at 400 de grees C 0.1C-9Cr-1W, V, Ta steels are prone to lower embrittlement as deduc ed from fracture surface observations of tensile specimens. Peculiarities o f fine structure and fracture mode, composition and precipitation reactions in steels during irradiation are discussed. (C) 1999 Published by Elsevier Science B.V. All rights reserved.