Defect-interface interactions

Abstract

Nanostructured materials contain an extremely high density of interfaces. The properties of these materials when exposed to extreme conditions of radiation dose, stress, deformation, or temperature are largely determined by defect-interface interactions. In this article, we review the present understanding of defect-interface interactions in single-phase and two-phase metal and oxide nanocomposites, emphasizing how interface structure affects interactions with point, line, and planar defects. We also review the crystallographic, chemical, and morphological stability of interfaces in different extreme environments: irradiation and mechanical deformation. Our current understanding of these topics prompts new questions that will maintain interfaces in crystalline solids at the frontier of materials research for years to come.

Grain size threshold for enhanced irradiation resistance in nanocrystalline and ultrafine tungsten

“…Therefore, these facetted bubbles are further evidence of significant vacancy trapping by the grain boundaries and it is reasonable to assume similar efficiency for coincident trapping of helium. The difference in sink efficiencies of different grain boundaries can also be experimentally confirmed by the observation of denuded zones (a bubble-free region in the vicinity of a boundary) as the width of the denuded zone is directly proportional to the grain boundary sink efficiency [26]. In the current study, the regions around grain boundaries demonstrated inconsistent behavior with some being denuded and some only partially denuded.…”

Imaging the in-plane distribution of helium precipitates at a Cu/V interface

“…Physical vapor deposited (PVD) multilayers of facecentered cubic (fcc) and body-centered cubic (bcc) metals have proven to be excellent model materials for studying interactions between solid-state interfaces and radiation-induced defects [1][2][3]. They have been especially fruitful for investigations of the nucleation, growth, and interaction of helium (He) precipitates at fcc/bcc interfaces [4][5][6][7].…”

Evidence of a temperature transition for denuded zone formation in nanocrystalline Fe under He irradiation

“…Clustering of these defects can lead to the formation of more complex defect structures, such as vacancy loops, interstitial loops, voids, and bubbles, which all can potentially degrade the mechanical properties [3,4] of the irradiated material and ultimately cause failure [1]. To mitigate these detrimental effects, recent studies have investigated novel engineering materials with high densities of defect sinks, such as grain boundaries [5][6][7] or structural interfaces [8]. Grain boundaries are thought to act as defect sinks and, in particular, to enhance point defect annihilation by absorbing interstitials and then reemitting them back to recombine with nearby vacancies [9].…”

“…The resistance of grain boundaries to bubble formation in the grain matrix was correlated to the formation of denuded zones near the grain boundaries, which is a function of grain boundary sink efficiency [8]. Experimentally, insight about grain boundary sink efficiency can be gained through examining denuded zone formation in the irradiated samples.…”

“…Helium-stabilized vacancies (small helium-vacancy complexes) will migrate more efficiently at 700 K. Thus, comparison of the 573 and 700 K experiments is reasonable. It should be mentioned that defect clusters can also be vacancy sinks which is ignored in the above equation [8].…”