Helium bubbles in nickel annealed at T>0.7Tm

Helium bubble evolution in a Zr–Sn–Nb–Fe–Cr alloy during post-annealing: An in-situ investigation

“…The bubble size statistics from sample surface to 700 nm was not considered as the bubbles were too small to be measured. The density of the measured bubbles was the highest at a depth of around 1100 nm, which is consistent with the corresponding data simulated by SRIM [28,30,32].…”

“…Helium bubble coarsening via MC is controlled by the smaller bubble diffusion and coalescence with others bubbles to form larger bubbles. Ostwald ripening via He resolution and reabsorption would be expected to become effectively at temperatures about 0.5 T m (T m is the melting point) [30,43,47]. The E r values of all the samples are lower than 0.315 eV that is the critical value for He bubble coarsening mechanism controlled by MC in zirconium alloy [32,42].…”

“…The mechanism of the He bubble coarsening has been widely accepted and well described in literature [30,42,45,46]. There are three stages during He bubble evolution.…”

“…The advantages are as follows: 1) the implantation conditions can be well controlled and widely varied; 2) high He concentration can be achieved in a short time. There is substantial literature pertaining to the growth behaviors of gas bubbles in gas ion implanted ferritic alloys [21,25,26], aluminum alloys [27][28][29], nickel [30], tungsten [31] and also some zirconium alloys [32][33][34][35]. A blister of helium bubble has been reported by Zee et al in He implanted cold-worked Zr-2.5Nb alloy with He dose up to 2.0 × 10 18 He + /cm 2 at temperature from 100 K to 773 K [33,34].…”

Volume Defects: 3D Imperfections in Crystals

“…Zinkle and Farrell (1989) observed stacking-fault tetrahedra in neutron irradiated copper at 182 C, but voids formed between 220 C and 450 C. In this range, the copper also swelled. Helium bubbles in Ni have also been observed to form faceted voids, with a preference for void formation along grain boundaries (Chernikov et al 1997). Figure 9 illustrates some examples of void formation and void faceting in irradiated Cu and Ni.…”