The effect of interstitial gas atoms on mustructural evolution in self-ion irradiated nickel

Modeling injected interstitial effects on void swelling in self-ion irradiation experiments

“…Figure 1 of Gigax's study (here reproduced in Figure 5c) shows the two most salient features are the very strong impact of the injected interstitial effect to suppress, to very high doses, the void swelling throughout the injected ion range, and the appearance of a double-peak swelling distribution in the region in front of injected ion range. A similar observation was made in self-ion irradiations on pure nickel many years earlier [8,9]. Occasionally, double peaks are observed in other alloys, but the possibility cannot be discounted that compositional segregation along the range might be contributing to this observation.…”

“…The primary reasons for this lack of correspondence are various consequences of the increased DPA rate, very short ranges of the bombarding ion, consequences of strong gradients in DPA rate along the ion range and local defect imbalances arising from the bombarding ion [1,2,3,4,5,6,7,8,9,10,11]. Additionally, there are second-order effects such as ion-induced sputtering [1,12] and swelling-induced compressive states in the thin irradiated film that produce a one-dimensional (not three-dimensional as in the neutron irradiation case) flow of material toward the ion-incident surface [13,14].…”

“…Defect imbalances arising during ion irradiation arise from forward scattering involved with ion-atom collisions and the spatial distribution of injected ions, the latter having a very strong effect on swelling that is designated as the injected interstitial effect [6,7,8,9,10,11]. Garner et al review the result of experiments conducted on pure iron and various ferritic-martensitic alloys showing that the net effect of the various neutron-atypical aspects is to produce a depth dependence of void swelling that often bears no resemblance to the depth distribution of the atomic displacement rate [18].…”

Applications of Transient Grating Spectroscopy to Radiation Materials Science

“…3 Variations in the dose-property response of the same materials exposed to identical DPA have been observed as functions of temperature, 4 dose rate, 5 type of radiation, 6 duty cycle (beam rastering) of charged particle beams, [7][8][9] imposed stresses, 10 processing and resultant microstructure, 11 secondary precipitates or impurities, 12 and coinjection or cogeneration of gases such as helium during irradiation. 13,14 These variations demonstrate a clear difference between applied dose and accumulated damage for differing material and irradiation conditions. In addition, the actual analysis of radiation damage most often consists of time-consuming transmission electron microscopy (TEM) analysis, in which artifacts from sample preparation can often obscure the details of accumulated irradiation damage.…”

Effects of hydrogen and helium produced by transmutation reactions on void formation in copper isotopic alloys irradiated with neutrons

“…Consequently, it is impossible to know how helium or hydrogen influences nucleation and growth of voids, and whether there is an interaction between helium and hydrogen or not during void formation. To separate the intrinsic effects of helium or hydrogen and the synergetic effects of helium and hydrogen on nucleation and growth of voids, ion accelerator has been usually used so far for irradiation experiments [1][2][3][4]. The main advantage of ion accelerator is the easy control of experimental conditions and high damage rate.…”