Transmission electron microscopy (TEM) studies provide mechanistic understanding of nanoscale processes, whereas advanced synchrotron XRD (SXRD) enables precise measurements on volumes that are more representative of bulk materials. Therefore, the combined strengths of these techniques can provide new insight into irradiation-induced mechanistic processes. In the present study, their application to Zircaloy-2, proton-irradiated to 2.3, 4.7, and 7.0 dpa at 2 MeV and 350 °C and neutron-irradiated to 9.5 and 13.1 × 1025 n m−2 are exemplified. The application of correlative spectral imaging and structural TEM investigations to the phase transformation of Zr(Fe,Nb)2 precipitates in Low-Sn ZIRLO™, neutron-irradiated to 8.9–9 × 1025 n m−2, demonstrates the possibility of a Cr core nucleation site. Anomalous broadening is observed in SXRD profiles, which is believed to be caused by defect clusters and precursors to dislocation loop nucleation. The challenges to quantitative analysis of dislocations by SXRD are highlighted with reference to the segregation of Fe and Ni to basal planes and dislocation cores, observed by spectral imaging in the TEM.

We report on the formation of highly flexible and transparent TiO2/Ag/ITO multilayer films deposited on polyethylene terephthalate substrates. The optical and electrical properties of the multilayer films were investigated as a function of oxide thickness. The transmission window gradually shifted toward lower energies with increasing oxide thickness. The TiO2 (40 nm)/Ag (18 nm)/ITO (40 nm) films gave the transmittance of 93.1% at 560 nm. The relationship between transmittance and oxide thickness was simulated using the scattering matrix method to understand high transmittance. As the oxide thickness increased from 20 to 50 nm, the carrier concentration gradually decreased from 1.08 × 1022 to 6.66 × 1021 cm−3, while the sheet resistance varied from 5.8 to 6.1 Ω/sq. Haacke's figure of merit reached a maximum at 40 nm and then decreased with increasing oxide thickness. The change in resistance for the 60 nm-thick ITO single film rapidly increased with increasing bending cycles, while that of the TiO2/Ag/ITO (40 nm/18 nm/40 nm) film remained virtually unchanged during the bending test.

An alloy with the composition of Mg–3.7Zn–0.3Y–0.3Gd (in at.%) which contains quasicrystal phase was studied by multiple means. The as-cast alloy has dendritic structure and consists of α-Mg, I-phase, W-phase, and Mg–Zn precipitations. The alloy was forged one pass and annealed at 440 °C for 4 h, then followed by two passes of compressions. Eutectics were crushed and partially dissolved after deformation and annealing. The tensile strength increased after each forge pass. Submicron scale particles precipitated all around the grains during the deformations, and the amount of precipitations was proportional to the amount of deformations. These precipitated particles were observed by high resolution transmission electron microscopy (TEM). The existence of rhomboid W'-phase with face center cubic (FCC) structure and globular I-phase was confirmed. A quasi-periodicity lamellar phase combined with I-phase was founded, which was considered to be the transient phase between I-phase and W'-phase. This phase had orientation relationship with $\left( {1\bar 101} \right)$ of α-Mg basis and one of the 5-fold planar of the I-phase.

Small specimen testing techniques have a long history in nuclear material research due to the limitations posed by nuclear facilities. The limited space in reactors and the fact that the samples are oftentimes radioactive in addition to the increasing need to obtain mechanical properties from ion beam irradiated samples require small specimen mechanical testing. With the application of modern focused ion beam sample preparation techniques and the enhancement of nanoindentation instruments, the size scale has been moved to even smaller scales and new geometries. Micrometer and even nanometer size samples are feasible, but raise the question of comparability to large scale properties for engineering applications. In this review, we summarize available small scale materials testing techniques and potential shortcomings based on examples from the literature, as well as introduce novel experimental approaches conducted using microcompression testing, microbend bar testing, and nanoindentation at ambient and nonambient conditions.

Nanocrystalline cellulose (NCC) whisker obtained from acid hydrolysis of cotton was incorporated into the freezing polymerized PNIPA/clay hydrogels to prepare inorganic–organic hybrid nanocomposite hydrogels (named as C-NC gels). The influence of NCC on the properties of C-NC gels was investigated systematically. It was found that all C-NC gels exhibit similar lower critical solution temperature as that of NCC-free gels, being independent of the NCC content. However, with the increase of NCC content in C-NC gels, the swelling ability of gels decreases slightly while the response rate of gels increases gradually, the gels with high content of NCC exhibit an ultrarapid deswelling rate due to the amount of interconnected micropores appeared inside the gels. Moreover, the enhancement effect of increased NCC on the gels is significant, which is also determined by the swelling degree of gels directly. Comparably, for the gels with the same content of NCC, higher strength was found when the gels were kept in lower swelling ratio due to the stronger interaction of NCC through hydrogen bond in the gels.

The subject of hot ductility in C–Mn steels has been the focus of interest for a long time in materials science and engineering. However, the mechanism of loss in hot ductility continues to be unclear. In the present paper, the experimental hot ductility data in C–Mn steels involve: (i) a ductility trough appears at a certain temperature when the sample is held for a certain time at various temperatures after cooling quickly from a higher temperature; (ii) the ductility healing phenomenon which occurs with the duration of holding time; (iii) the ductility deteriorates with the increase of temperature difference between solution treatment temperature and test temperature during a tensile test; (iv) a minimum ductility appears when samples are cooled from a higher temperature to a lower one at a certain cooling rate; and (v) the formation of cavities at grain boundaries during tests. All of these are analyzed and calculated from the perspective of thermally induced nonequilibrium grain-boundary segregation (TNGS). Based on our detailed analyses, the loss in hot ductility of C–Mn steels is ascribed to TNGS of impurities.

High-aspect-ratio (HAR) pillar arrays offer large surface area, well-defined surface topography, and large mechanical compliance. In this Prospective, we showcase micro- and nanopillar array systems that exploit the responsiveness and/or harness the mechanical instabilities for myriad surface-mediated applications, including tunable wetting, adhesion, optical properties, and actuation. In each application, we start with biological examples with HAR pillar structures, and discuss strategies to fabricate responsive HAR polymer pillar structures. We then discuss approaches to tune the surface topography, such as via bending, tilting, expansion or contraction, and collapsing of the pillars, and the resulting change of surface and optical properties, and their dynamic actuation. In each system, we discuss the controllability and recoverability of pillar deformation.