Irradiation damage of single crystal, coarse-grained, and nanograined copper under helium bombardment at 450 °C

Abstract

The irradiation damage behaviors of single crystal (SC), coarse-grained (CG), and nanograined (NG) copper (Cu) films were investigated under Helium (He) ion implantation at 450°C with different ion fluences. In irradiated SC films, plenty of cavities are nucleated, and some of them preferentially formed on growth defects or dislocation lines. In the irradiated CG Cu, cavities formed both in grain interior and along grain boundaries; obvious void-denuded zones can be identified near grain boundaries. In contrast, irradiation-induced cavities in NG Cu were observed mainly gathering along grain boundaries with much less cavities in the grain interiors. The grains in irradiated NG Cu are significantly coarsened. The number density and average radius of cavities in NG Cu was smaller than that in irradiated SC Cu and CG Cu. These experiments indicate that grain boundaries are efficient sinks for irradiation-induced vacancies and highlight the important role of reducing grain size in suppressing radiation-induced void swelling.

Statistical analysis of the interaction between irradiation-induced defects and triple junctions

“…Yu et al [4] have observed that reducing grain size lowers the density of He bubbles in Fe irradiated with He ions. Likewise, Han et al [5] observed that the density and size of cavities were reduced in nanograined Cu as compared to coarse-grained Cu when subjected to He irradiation. Similarly, Alsabbagh et al [6] observed a reduction in radiation-induced hardening and embrittlement in ultra-fine-grained steel as compared to coarse-grained steel, while Sun et al [7] quantified the reduction in swelling and swelling rate in 304 L stainless steel when using an ultra-fine-grained structure.…”

In situ Transmission Electron Microscopy He+ implantation and thermal aging of nanocrystalline iron

“…Due to the high density of grain boundaries and interfaces, a number of nanostructured materials have displayed a higher tolerance to radiation damage compared to their coarse-grained counterparts. For example, reduced defect density and increased radiation tolerance in nanocrystalline metals has been reported for ion irradiated Fe [3,9], Pd [10], Cu [11], W [12], and Ni [13,14].…”

Role of interfaces on the trapping of He in 2D and 3D Cu–Nb nanocomposites

“…Ultrafine-grained single phase materials have been shown to trap helium at grain boundaries, but they are not particularly efficient and can coarsen at high temperatures or during irradiation [10][11][12][13]. Interphase boundaries in oxide dispersion strengthened (ODS) steels have also been shown to be good defect sinks, and they are stable in the extreme environment of a nuclear reactor [14][15][16].…”