The influence of the transmutation element rhenium (Re) on defect evolution in tungsten (W) during irradiations with heavy ions and deuterium (D) plasma was investigated. Rolled W and W–5Re alloy (Re concentration 5 wt.%) were irradiated with 500 keV iron ions to 0.06 and 0.6 dpa (displacement per atom), and deuterium plasma at 38 eV/D to a fluence of 2.2 × 1025 D m−2 at ∼373 K. The results of Doppler broadening spectroscopy by the positron annihilation technique indicate that more or larger vacancy-type defects were produced in W than in the W–5Re during Fe ion irradiation, suggesting the important role of Re on inhibiting the migration and/or clustering of vacancies. The much smaller and shallower blistering in W–5Re than in W after the same D plasma exposure points to the pinning effects on dislocations by Re. The total retained D amounts in W–5Re and W materials are comparable, but with very different concentration profile at corresponding depth. This is explained by the blister formation exerting influence on the D inward diffusion. Demonstrating the important role of Re on the defect evolution in W under irradiation, the present work provides an enhanced understanding on the possible effects of neutron irradiation on the performance of plasma-facing materials in future fusion devices.
Deuterium trapping at defects created with neutron and ion irradiations in tungsten