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Concentrated solid solution alloys (CSAs) comprising multiple components have unlocked novel pathways for materials design, particularly in enhancing radiation tolerance. It is imperative to detect early-stage radiation damage in CSAs to gain insights into damage initiation and accumulation mechanisms. In this study, nanoindentation is employed to assess the impact of irradiation on deformation mechanisms in single crystal CSAs, specifically NiCo, NiFe, and NiCoFeCr. It is discovered that pile-up behavior in CSAs significantly affected by irradiation: pile-up induces 10–20 % increase in the contact area before irradiation that is independent of the penetration depth but 20–30 % after irradiation, which substantially affects hardness analyses. Within the context of strain gradient plasticity theory, distinct radiation-induced hardening in three CSAs is interpreted by two components: one is from the radiation-induced defects, and the other is the increase in density of geometrically necessary dislocations (GNDs) associated with indentation size effect (ISE). Quantitative analysis shows that the radiation-induced defects produce obvious hardening in NiFe and NiCoFeCr sample, but not in the NiCo sample. Meanwhile, the irradiation induces a higher GND density in NiCo and NiFe, but not in NiCoFeCr, which is interpreted by the volume change of the plastic zone. [ABSTRACT FROM AUTHOR]

Recent studies have shown that chemical immiscibility is important to achieve enhanced radiation tolerance in metallic multilayers as immiscible layer interfaces are more stable against radiation induced mixing than miscible interfaces. However, as most of these immiscible systems have incoherent interfaces, the influence of coherency on radiation resistance of immiscible systems remains poorly understood. Here, we report on radiation response of immiscible Cu/Fe multilayers, with individual layer thickness h varying from 0.75 to 100 nm, subjected to He ion irradiation. When interface is incoherent, the peak bubble density decreases with decreasing h and reaches a minimum when h is 5 nm. At even smaller h when interface is increasingly coherent, the peak bubble density increases again. However, void swelling in coherent multilayers with smaller h remains less than those in incoherent multilayers. Our study suggests that the coherent immiscible interface is also effective to alleviate radiation induced damage. [ABSTRACT FROM PUBLISHER]

Materials subjected to high dose irradiation by energetic particles often experience severe damage in the form of drastic increase of defect density, and significant degradation of their mechanical and physical properties. Extensive studies on radiation effects in materials in the past few decades show that, although nearly no materials are immune to radiation damage, the approaches of deliberate introduction of certain types of defects in materials before radiation are effective in mitigating radiation damage. Nanostructured materials with abundant internal defects have been extensively investigated for various applications. The field of radiation damage in nanostructured materials is an exciting and rapidly evolving arena, enriched with challenges and opportunities. In this review article, we summarize and analyze the current understandings on the influence of various types of internal defect sinks on reduction of radiation damage in primarily nanostructured metallic materials, and partially on nanoceramic materials. We also point out open questions and future directions that may significantly improve our fundamental understandings on radiation damage in nanomaterials. The integration of extensive research effort, resources and expertise in various fields may eventually lead to the design of advanced nanomaterials with unprecedented radiation tolerance. [ABSTRACT FROM AUTHOR]

• The temperature-dependent void swelling of additively manufactured 316L SSs was investigated for the first time. • The void swelling behaviors of additively manufactured 316L and cold-worked 316L SSs were systematically compared. • The dislocations trapped at cell walls and dislocation networks induced by cold work probably functioned differently in void swelling. We studied the void swelling in stress-relieved (SR) additively manufactured (AM) 316L stainless steel (SS) in comparison with hot-isostatic pressed (HIP) AM 316L counterparts with identical chemistry. To understand the role of dislocation cell structure in SR AM 316L SS, we also included cold-worked (CW) 316L SS with various CW levels for dislocation networks. The irradiation damage of 30 displacements per atom (dpa) in AM and CW 316L SSs were compared after 5 MeV Fe2+ ion irradiations at 500 °C, 550 °C, and 600 °C, respectively. To investigate the temperature and dose dependence, the AM 316L SSs were further irradiated to 100 dpa at 400 °C and 600 °C. Results show that the void welling in SR AM 316L SS is more severe than in HIP AM 316L SS, in terms of a higher void density and a deeper void nucleation depth through all the examined conditions. This is ascribed to a more extended incubation period in HIP AM 316L SS. Beyond the incubation, both samples proceeded at a similar swelling rate. Dislocation networks from cold-working can effectively suppress void swelling, while dislocation cell structures containing entangled dislocations on cell walls cannot. The distinct responses indicate the potential influence of dislocation configuration on void swelling. Despite some relevant data are available, our understandings of radiation damage in AM 316L SSs are still limited. [ABSTRACT FROM AUTHOR]