Crack propagation behaviors in a precracked single crystal Ag under mode I loading at different temperatures are studied by molecular dynamics simulation. The simulation results show that the crack propagation behaviors are sensitive to external temperature. At 0 K, the crack propagates in a brittle manner. Crack tip blunting and void generation are first observed followed by void growth and linkage with the main crack, which lead to the propagation of the main crack and brittle failure immediately without any microstructure evolution. As the temperature gets higher, more void nucleations and dislocation emissions occur in the crack propagation process. The deformation of the single crystal Ag can be considered as plastic deformation due to dislocation emissions. The crack propagation dynamics characterizing the microstructure evolution of atoms around the crack tip is also shown. Finally, it is shown that the stress of the single crystal Ag changes with the crack length synchronously.

The progressive build up of fission products inside different nuclear reactor components can lead to significant damage of the constituent materials. We demonstrate the use of time-domain thermoreflectance (TDTR), a nondestructive thermal measurement technique, to study the effects of radiation damage on material properties. We use TDTR to report on the thermal conductivity of optimized ZIRLO, a material used as fuel cladding in nuclear reactors. We find that the thermal conductivity of optimized ZIRLO is 10.7 ± 1.8 W m−1 K−1 at room temperature. Furthermore, we find that the thermal conductivities of copper–niobium nanostructured multilayers do not change with helium ion irradiation doses of 1015 cm−2 and ion energy of 200 keV, demonstrating the potential of heterogeneous multilayer materials for radiation tolerant coatings. Finally, we compare the effect of ion doses and ion beam energies on the measured thermal conductivity of bulk silicon. Our results demonstrate that TDTR can be used to quantify depth dependent damage.

We describe measurements aimed at tracking the subsurface energy deposition of ionic radiation by encapsulating an irradiated oxide target within multiple, spatially separated metal–oxide–semiconductor (MOS) capacitors. In particular, we look at incident kinetic energy and potential energy effects in the low keV regime for alkali ions (Na+) and multicharged ions (MCIs) of ArQ+ (Q = 1, 4, 8, and 11) incident on the as-grown layers of SiO2 on Si. With the irradiated oxide encapsulated under Al top contacts, we record an electronic signature of the incident ionic radiation through capacitance–voltage (C–V) measurements. Both kinetic and potential energy depositions give rise to shifted C–V signatures that can be directly related to internal electron–hole pair excitations. The MCI data reveal an apparent power law dependence on charge state, which is at odds with some prior thin foil studies obtained at higher incident energies.

Positron annihilation lifetime spectroscopy is used to study the structural changes in amorphous arsenic sulfides of a binary As–S system induced by high-energy γ-radiation of 60Co source. It is demonstrated that radiation-induced effects in positron trapping modes of the studied glasses are in strict correlation with shift of their fundamental optical absorption edge. The γ-induced physical aging is shown to be dominated in the rejuvenated S-rich glasses, thermally induced physical aging accompanies annealing of the rejuvenated g-AsxS100−x, while coordination topological defects are character for near-stoichiometric glasses (both annealed and rejuvenated). The competitive processes of free-volume void evolutions such as agglomeration–fragmentation, expansion–contraction, and charging–discharging are considered as possible stages of radiation- and thermally induced structural transformations. The meaningful model for γ-irradiation and relaxation-driven evolution in the void structure of As–S glasses is proposed. The free-volume evolution in g-AsxS100−x associated with thermally and γ-induced physical aging is shown to be consistent with a void fragmentation process, while the formation of γ-induced coordination topological defects leads mainly to void charging.

Spintronics utilizes spin or magnetism to provide new ways to store and process information and is primarily associated with the utilization of spin polarized currents in memory and logic devices. With the end of silicon transistor technology in sight, spintronics can provide new paradigms for information processing and storage. Compared to charge based electronics, the advantages of magnetism/spin based devices are nonvolatility and ultra low power. In particular, magnetoresistive random access memories (MRAMs) are known to be “Rad Hard” [HXNV0100 64K x 16 Non-Volatile Magnetic RAM (www.honeywell.com/aerospace), S. Gerardin and A. Paccagnella, IEEE Trans. Nucl. Sci.57(6), 3016–3039 (2010), R.R. Katti, J. Lintz, L. Sundstrom, T. Marques, S. Scoppettuolo, and D. Martin, Proceedings of IEEE Radiation Effects Data Workshop, 103–105 (2009)] and are considered to be critical components for space and military systems due to their very low power consumption and nonvolatility. However, advances in the magnetic nanostructures and new materials for the scalability of MRAM and other potential applications require a re-evaluation of their radiation hardness. This review focuses mainly on recent progress in understanding the effects of irradiation on the magnetic materials and magnetic structures that are related to MRAM technology. Up to date, the most pronounced effects on the microstructures and the properties are linked to the displacement damage associated with heavy ion irradiation; however, the thermal effect is also important as it acts as an annealing process to recover the damage partially. Critical metrics for the magnetic tunnel junctions for postmortem characterizations will also be discussed. Finally, with the introduction of new perpendicular magnetic layers and the very thin MgO barrier layer in the next generation MRAM, the effects of the ionization damage shall be studied in the future.

It is well established that exposure of metallic structural materials to irradiation environments results in significant microstructural evolution, property changes, and performance degradation, which limits the extended operation of current generation light water reactors and restricts the design of advanced fission and fusion reactors. Further, it is well recognized that these irradiation effects are a classic example of inherently multiscale phenomena and that the mix of radiation-induced features formed and the corresponding property degradation depend on a wide range of material and irradiation variables. This inherently multiscale evolution emphasizes the importance of closely integrating models with high-resolution experimental characterization of the evolving radiation-damaged microstructure. This article provides a review of recent models of the defect microstructure evolution in irradiated body-centered cubic materials, which provide good agreement with experimental measurements, and presents some outstanding challenges, which will require coordinated high-resolution characterization and modeling to resolve.