Monotonic and cyclic tension–tension tests with an upper stress in the GPa regime have been performed on Cu–Si nanowires. The results show that the exceptional high strength of these nanomaterials is maintained or even improved upon cyclic loading. Post-mortem transmission electron microscopy gives insight in the microstructural evolution. Fatigue-induced grain growth correlates with an observed increase in compliance, the formation of dislocation networks, and an increase in tensile strength.

Spherical and conical nanoindentation experiments were performed for the same polymer specimens to compare Young's moduli measured from the elastic loading and unloading curves, and bending experiments. Finite-element simulation was employed to ensure pure elastic deformation during spherical nanoindentation. The moduli measured from the elastic loading curves using Hertz's contact law are very close to the bending moduli, because both measurements were conducted under the same elastic deformation. However, the moduli measured from the elastic unloading curves are up to 60% higher than the bending moduli owing to plastic deformation close to the sharp conical indenter tip.

Robust superhydrophobic surfaces can improve the performance of various applications. Considerable research has focused on developing superhydrophobic surfaces, but in these studies, superhydrophobicity was attained using polymeric materials, which deteriorate under harsh environments. Recently, it has been shown that rare-earth oxide ceramics are hydrophobic and since they are ceramics, they withstand harsh environments including high temperature. Here we fabricate a superhydrophobic surface by texturing a ceria pellet using laser ablation. We demonstrate water repellency by showing an impinging water droplet bouncing off the surface. This study extends the possibility of producing robust superhydrophobic ceramics using accessible techniques for industrial applications.

Large volume fractions of Mn–Ni–Si (MNS) precipitates formed in irradiated light water reactor pressure vessel (RPV) steels cause severe hardening and embrittlement at high neutron fluence. A new equilibrium thermodynamic model was developed based on the CALculation of PHAse Diagrams (CALPHAD) method using both commercial (TCAL2) and specially assembled databases to predict precipitation of these phases. Good agreement between the model predictions and experimental data suggest that equilibrium thermodynamic models provide a basis to predict terminal MNS precipitation over wider range of alloy compositions and temperatures, and can also serve as a foundation for kinetic modeling of precipitate evolution.

Nanoindentation experiments have been carried on Arabidopsis thaliana using spherical tungsten tips. Load–displacement plots obtained from experiments suggest that there is an optimum diameter of tip size which can be used to safely penetrate the tip through the cell wall. Based on the exact tip size used in the experiments and the measured load–displacement response, the failure stress was calculated using the experimental data in conjunction with a computational model. The value of failure stress was investigated in hypertonic (plasmolyzed), isotonic, and hypotonic (turgid) samples.

Electrochemical dissolution by congruent oxidation of Fe Pd in 1 M HCl solution was strongly controlled by crystallographic orientation. Anodic dissolution was characterized over a wide variety of grain surface plane orientations providing a detailed view of the crystallographic nature of oxidative dissolution and surface facet evolution as a function of grain orientation. Near {100}-oriented grains retained low surface roughness after corrosion and low dissolution rates. Grains with orientation within 2° of {111} were also topographically smooth after dissolution and were nearly as corrosion resistant as {100} grains. Overall dissolution depth depended linearly on crystallographic angle within 40° of {100} and within 10° of {111} planes. Post-corrosion surface faceting and dissolution were substantially increased at grain orientations near {110} and were highest between 10° and 20° from the {111} plane normal. Grains at these crystallographic angles roughened during oxidative dissolution by forming complex semi-periodic topographies. These finely spaced arrays of terraces and ledges likely consisted of combinations of more corrosion resistant low-index planes. Therefore, the overall corrosion depth within a grain possessing an initially irrational crystal orientation was determined by the amount of dissolution required to expose new, slowly dissolving surface facets with low-index orientations. Computations of Fe–Pd alloy surface energies and surface atom coordination as a function of crystal orientation are utilized to help support this explanation.

Bacillus pasteurii was used as synthesis director for the formation of hollow cylinder and helical NiO micro/nanostructure under urea hydrolysis conditions. Bacteria were capable of precipitating nickel product from nickel solution by metabolic processes. An appropriate amount of both water and bacterial solution were required to precipitate the nickel product in good yield. The average crystallite size of NiO was 11.45 nm and lengths of the cylinder and helices were non-uniform (~2–7 µm) and were varied with bacterial body structure template. The present study demonstrates a feasibility of synthesizing bacteria-guided metal oxide crystals for various functional applications.

Compression loading on CrN/Cu/Si(100) micropillars containing 45°-inclined interfaces yielded unequivocal evidence of shear plastic flow within Cu thin films confined between non-deforming Si and CrN. Confined shear plastic flow occurred over Cu thicknesses between ~100 and 1200 nm, with a monotonically increasing flow stress as the thickness decreases. The demonstration of a significant dependence of the shear flow stress on the confined Cu film thickness offers a new example of scale-dependent plasticity, and a new experimental test case for non-local plasticity theories.