Radiation-induced strengthening in EB welds of Mo–Re alloys during high temperature neutron irradiation

Mo–Re alloys have been known as excellent construction materials with good thermal stability and resistivity for chemical corrosion. These alloys may be fabricated into equipments for various chemical plants and new energy facilities such as fusion reactor. Accordingly it is interesting to elucidate the weldability and radiation performance of Mo–Re alloys in the actual constructions. In this study Mo–Re welds with 16–50% Re exhibited a large radiation-induced strengthening and embrittlement by irradiation at ∼1073 K to ∼5 × 1021 cm−2 (E > 0.1 MeV). High temperature neutron irradiation leads to intensive homogeneous nucleation of Re-rich σ-phases in all studied Mo–Re alloys that equalizes the difference in mechanical properties between melting zone, heat-affected zone and base metal. As a result, all parts of as-irradiated welds displayed approximately same level of strength. Therefore, the application of EB welding in Mo–Re constructions operating under high temperature neutron irradiation does not limit lifetime of such constructions.