Radiation Tolerance in Nano-Structured Crystalline Fe(Cr)/Amorphous SiOC Composite

Abstract

The management of irradiation defects is one of key challenges for structural materials in current and future reactor systems. To develop radiation tolerant alloys for service in extreme irradiation environments, the Fe self-ion radiation response of nanocomposites composed of amorphous silicon oxycarbide (SiOC) and crystalline Fe(Cr) were examined at 10, 20, and 50 displacements per atom damage levels. Grain growth in width direction was observed to increase with increasing irradiation dose in both Fe(Cr) films and Fe(Cr) layers in the nanocomposite after irradiation at room temperature. However, compared to the Fe(Cr) film, the Fe(Cr) layers in the nanocomposite exhibited ~50% less grain growth at the same damage levels, suggesting that interfaces in the nanocomposite were defect sinks. Moreover, the addition of Cr to α-Fe was shown to suppress its grain growth under irradiation for both the composite and non-composite case, consistent with earlier molecular dynamic (MD) modeling studies.

Kr ion irradiation study of polymer‐derived SiFeOC–C–SiC nanocomposite

“…18,19 Studies carried out on Cu/Nb, 20 Cu/V, 21 and Fe/W 19 revealed that nanoscopic interfaces (defect sinks) promote the recombination of defects, suppress void/bubble formation, and are more resilient to irradiation damages (compared to microcrystalline). 22 Nanocrystalline Fe samples irradiated with He ions have a lower He bubble density than their microcrystalline counterparts. 23 Simulations revealed that defect sink site concentration is proportional to the amount of free volumes (regions where defects are either not present or are present but do not result in measurable changes) formed.…”

“…The presence of Fe in the SiOC matrix yields a new class of ceramic/metal composites that are stable toward heat and radiation damage. 19,22,23 Recent studies revealed that Fe catalyst encourages the formation of SiC via intermediate Fe 3 Si formation. 27,28 The use of an iron precursor in SiOC not only helps the formation of nanocrystals of β-SiC and FeSi but also enhances the mechanical integrity of SiOC coatings.…”

“…The presence of defect sink sites, such as grain boundaries and interfaces, can enhance radiation damage resistance 18,19 . Studies carried out on Cu/Nb, 20 Cu/V, 21 and Fe/W 19 revealed that nanoscopic interfaces (defect sinks) promote the recombination of defects, suppress void/bubble formation, and are more resilient to irradiation damages (compared to microcrystalline) 22 . Nanocrystalline Fe samples irradiated with He ions have a lower He bubble density than their microcrystalline counterparts 23 .…”

“…The presence of Fe in the SiOC matrix yields a new class of ceramic/metal composites that are stable toward heat and radiation damage 19,22,23 . Recent studies revealed that Fe catalyst encourages the formation of SiC via intermediate Fe 3 Si formation 27,28 .…”