Effects of transmutation elements on the defect structure development of W irradiated by protons and neutrons

Hardening of self ion implanted tungsten and tungsten 5-wt% rhenium

“…At a dose of 0.15 dpa there is a hardness increase of 0.6-2.4 GPa which is similar to that seen in the ion implantation experiments carried out here. Above 0.6 dpa there are only two data points for neutron implanted materials [22,23] and these show hardness increases of greater than 3.5 GPa, which are much higher than those seen in the ion implantation experiments. These discrepancies between neutron irradiated and ion irradiated samples could arise from various sources, including differences in purity of starting material, differences in dose rates and the differing irradiation temperatures.…”

“…Experiments are ongoing in this area to further understand the effects of irradiation temperature. Work by He et al [23] has shown that W-3 wt%Re irradiated with neutrons and protons at 500°C shows differing hardening response, with the proton-irradiated material showing a change in hardness of 105 Hv compared with 71 Hv for the neutron-irradiated materials. These are both light particles and a tungsten ion will be 184 times heavier, so the resulting damage structures may be significantly different.…”

“…Of particular interest are the changes in hardness due to irradiation as a function of rhenium concentration, for alloys containing between 0 and 26 wt%Re [14,[21][22][23][24][25][26]. In these studies the maximum damage level attained was only 1.6 dpa, which is significantly smaller than the potential levels of damage expected in a commercial nuclear fusion reactor, of up to 30 dpa per year [3,4].…”

Ion-irradiation-induced clustering in W–Re and W–Re–Os alloys: A comparative study using atom probe tomography and nanoindentation measurements

“…Although the equilibrium W-Re-Os phase diagram predicts complete solubility at this composition [5], the mechanical properties of components could be severely degraded due to the formation of irradiationinduced solute-rich clusters as the precursors to sigma and chi precipitates [6,7]. Previous studies of the irradiation responses of these systems are sparse and limited to compositions with more than 3 at.% rhenium and/or osmium present [8][9][10][11]. Tanno et al [8] irradiated W-3Os, W-5Re and W-5Re-3Os in the JOYO Japanese nuclear research reactor.…”

Modeling fast neutron irradiation damage accumulation in tungsten

“…In a series of recent papers, Hasegawa and collaborators have shown that Re precipitation suppresses void and dislocation loop density accumulation and size growth [7,8,9], although they observe that subsaturated Re precipitation above 1 dpa gives rise to very dramatic hardening increases. This precipitation of soluble Re under irradiation was observed by Williams et al during EBR-II experiments in 1983 [10].…”