Experimental determination of the deuterium binding energy with vacancies in tungsten

Abstract

Deuterium (D) interaction with vacancies in tungsten (W) was studied using thermal desorption spectroscopy (TDS). In order to obtain a TDS spectrum with a prominent peak corresponding to D release from vacancies, a special procedure comprising damaging of a recrystallized W sample by low fluences of 10 keV/D ions, its annealing, and subsequent lowenergy ion implantation, was utilized. This experimental sequence was performed several times in series; the only difference was the TDS heating rate that varied in the range of 0.15-4 K/s. The sum of the D binding energy (E b) with vacancies and the activation energy for D diffusion (E D

Predictive model of hydrogen trapping and bubbling in nanovoids in bcc metals

“…4bare attributed to large nanovoids (mostly 6 − 15 ), confirming the experimental speculations19,20 . Aside from some minor discrepancy at low temperatures which may contributed by other defects like dislocations or grain boundaries19,20 , our simulations accurately reproduce the experimental observations.…”

“…These annealed samples were subsequently implanted by low-energy D ions, followed by TDS measurements with different heating rates. The TDS spectra data corresponding to radiation defects (reproduced from Refs 19,20 ) were shown in Fig. 4.…”

“…However, atomic details of H bubble nucleation, growth and agglomeration processes are difficult or even impossible to observe in-situ. An alternative method to study H bubble formation is to measure H thermal desorption rates during isochronal annealing [19][20][21][22][23] , which provides energetic information of H de-trapping from nanovoids in metals. Nevertheless, H thermal desorption spectra usually relate to multiple types of crystal defects at different depths 24 , therefore difficult to interpret.…”

“…Thermal desorption spectra of deuterium from W after irradiated by 10 keV/D ions to the fluence of 3 × 10 19 D/m 2 , annealed at (a) 550 K and (b) 800K for 5 min to render small and large nanovoids, implanted with 0.67 keV/D ions to the fluence of 10 19 D/m 2 , then annealed with different heating rates. Lines are multiscale modelling results, while symbols are experimental data from Zibrov et al (open) and Ryabtsev et al (solid)19,20 .…”

Hydrogen isotope accumulation in the helium implantation zone in tungsten

“…TDS spectrum and D depth profile can be fitted with two trap types assuming a homogenous trap concentration for both trap sites down to 2 µm. In a recent study frequency factors and de-trapping energies were derived from the TDS peak shift applying different ramp rates [30,31] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 A c c e p t e d M a n u s c r i p t 8 and E2 T = 1.38 eV one can describe the measured TDS spectrum. According to the desorption temperatures and de-trapping energies the traps could be attributed to vacancies and dislocation loops, respectively [32].…”