EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Tungsten is the prime candidate for plasma-facing components in future nuclear fusion reactors because it is capable to withstand harsh operating conditions and neutron irradiation. It is known that high-energy neutrons that occur in nuclear fusion reactions change the structure of the material and its properties. In particular, they create displacement damages and transmutations. During the operation of the reactor, tungsten will transmute into rhenium (Re) and subsequently osmium (Os). The predictable damage level in the facing components will be more than 1 dpa (displacement per atom) and the accumulation of Re will be less than 1 at.%. Because the reproduction of conditions of the reactor is quite complicated, experiments of the structural damage imitation by irradiation with heavy ions got widespread use. Now there is a big number of investigations of the irradiation hardening behavior of neutron-irradiated tungsten but the general picture is still not clear. This study examines the microstructure of W–6at.%Re induced by 5.6 MeV Fe^+2 ion irradiation to 5 dpa at 500 K. Microstructure of the alloy was obtained by Atom Probe Tomography (APT) and Transmission Electron Microscopy (TEM). TEM has shown presence of dislocation loops, with the size 2-15 nm and the number density 1.2×10^23 m^-3. Needle-shaped precipitations and rhenium-enriched clusters were observed by APT technique. The increase in hardness was studied using nanoindentation. The alloy after irradiation exhibited a hardness of 1.6 GPa.