Mechanical properties of irradiated ODS-EUROFER and nanocluster strengthened 14YWT

Irradiations to 1.5 dpa at 300-750 °C were conducted to investigate the changes in mechanical properties of an advanced nanocluster strengthened ferritic alloy, designated 14YWT, and an oxide dispersion strengthened ferritic alloy ODS-EUROFER. Two non-dispersion strengthened variants, 14WT and EUROFER 97, were also irradiated and tested. Tensile results show 14YWT has very high tensile strengths and experienced some radiation-induced hardening, with an increase in room temperature yield strength of 125 MPa after irradiation, while results for ODS-EUROFER show a 275 MPa increase following irradiation. Master curve fracture toughness analysis show 14YWT has a cryogenic T_o reference temperatures before and after irradiation of about −188 and −176 °C, respectively, and upper-shelf K_JIc values between 175 and 225 MPa√m. The favorable fracture toughness properties and resistance to radiation-induced changes in mechanical properties observed for 14YWT are attributed to a fine grain structure and high number density of Y-Ti-O nanoclusters.