Mechanical and microstructural characterization of electron beam welded reduced activation oxide dispersion strengthened – Eurofer steel

Electron beam welding has been considered as a potential process to join divertor structures made of reduced activation ferritic martensitic 9Cr% ODS-Eurofer steel. Strips of this ODS steel were welded under well defined conditions. fferent post-weld heat treatments were applied to investigate their impact on the mechanical and microstructural properties of the welded joints. Miniaturised tensile specimens were used to determine the tensile behaviour in the temperature range between RT and 773 K. KLST specimens were used for Charpy impact tests. The tensile strength decreases to values similar to Eurofer steel without ODS strengthening. The impact behaviour is far worse than both, of ODS-Eurofer and Eurofer steel. crostructure of the weld and heat-affected zone as well as the fracture surface of the samples were examined using optical and scanning electron microscopy, dual-beam SEM/FIB, low magnification and analytical transmission electron microscopy. The changes of the mechanical properties can be well correlated with the detected changes of micro- and nano-structure.