Tensile properties and fracture mode of a wrought ODS molybdenum sheet following fast neutron irradiation at temperatures ranging from 300 °c to 1000 °c

A commercially available wrought oxide dispersion strengthened (ODS) molybdenum alloy was irradiated in the high flux isotope reactor (HFIR) at 294-936 °C to neutron fluences between 2.28 and 24.7 × 10²⁵ n/m² (E > 0.1 MeV) or (1.2-13.1 dpa-Mo). Irradiation of ODS molybdenum at 300 °C and 600 °C results in large increases in strength (57-173%). The DBTT for 300 °C-irradiated ODS Mo was 800 °C, which is the same as observed for low carbon arc cast (LCAC) and TZM molybdenum irradiated to the same dose. The DBTT for 600 °C-irradiated ODS Mo was room-temperature, which is a significant improvement over the DBTT values determined for LCAC (300 °C) and TZM (700 °C) and from literature data. The micro-structural feature of small, elongated grains likely enhances the resistance of ODS to irradiation embrittlement. Irradiation of ODS Mo at 870-1000 °C resulted in small increases in yield strength (10-34%) with a post-irradiated DBTT comparable to non-irradiated material (-100 °C).