Despite extensive research, the understanding of the fundamental processes governing yielding and plastic flow in metallic glasses remains poor. This is due to experimental difficulties in capturing plastic flow as a result of a strong localization in space and time by the formation of shear bands at low homologous temperatures. Unveiling the mechanism of shear banding is hence key to developing a deeper understanding of plastic deformation in metallic glasses. We will compile recent progress in studying the dynamics of shear-band propagation from serrated flow curves. We will also take a perspective gleaned from stick-slip theory and show how the insights gained can be deployed to explain fundamental questions concerning the origin, mechanism, and characteristics of flow localization in metallic glasses.

High-quality Zn3P2 nanowires are synthesized at a temperature as low as 350 °C using Zn foil and trioctylphosphine by chemical reflux method. Scanning electron microscopy and transmission electron microscopy (TEM) images show their diameters vary from ∼15 to 70 nm. Energy dispersive x-ray spectroscopy and nanobeam electron diffraction patterns in combination with structure factor simulation reveal that the nanowires have tetragonal α-Zn3P2 structure. Based on high-resolution TEM images and their fast Fourier transform patterns, Zn3P2 nanowires are considered to grow on a vicinity of the possibly highest surface energy plane of (101) with a growth direction parallel to [101].

The formation of interfacial η′-Cu6Sn5 in Sn–0.7Cu/Cu solder joints at different aging temperatures was studied using x-ray diffraction (XRD). The time-temperature-formation curve was obtained and is discussed based on the phase transformation from existing η-Cu6Sn5 and interfacial reaction at temperatures below 186 °C. A minimum formation time was observed in the temperature range of 135–150 °C.

Breakdown of porous materials by salts occurs when growing crystals exert pressure on the pore walls, inducing stress in the material that exceeds its tensile strength. In this work, we quantify the mechanical stresses caused by a particularly destructive mechanism: the dissolution of an anhydrate (thenardite, Na2SO4) followed by precipitation of a hydrated salt (mirabilite, Na2SO4·10H2O). Stresses are measured using a composite specimen consisting of a plate of glass bonded to a plate of limestone (CaCO3) whose pores are impregnated with thenardite. As water wicks into the limestone, thenardite dissolves and mirabilite precipitates. The limestone expands from the pressure exerted by the salt resulting in deflection of the composite, and the stresses can be obtained from an elastic analysis. Synchrotron x-ray diffraction reveals the dissolution–crystallization rate. Numerical modeling shows that the stresses are affected by the kinetics of crystallization and dissolution, permeability, and mechanical properties of the stone, allowing us to determine the amount of salt that causes material fracture.

The time-resolved evolution of intermetallic phase formation in the system pure Sn (polycrystalline coating with a thickness of several microns) on pure Cu (polycrystalline bulk substrate) was investigated in detail by means of focused ion beam and transmission electron microscopy and x-ray diffraction during aging at room temperature for a period of about 1 year. The availability of this coherent data base allowed interpretation of the evolution of intermetallic compound (IMC) formation in terms of interface thermodynamics and interdiffusion kinetics. On this basis spontaneous Sn whiskering on the surface of the Sn coating as a consequence of intermetallic phase (Cu6Sn5) formation along, specifically, Sn grain boundaries intersecting the Sn/Cu interfaces could be discussed. Moreover, a treatment to mitigate spontaneous Sn whiskering on the basis of thermodynamic control of the IMC morphology was proposed.

The Si–P system at high temperatures up to 6 wt%P was investigated. Silicon–phosphorus alloys were prepared through the melting of silicon–phosphorus mixtures in closed silica tubes. Microstructural studies indicated two phases in the alloys, i.e., a solid solution of P in Si and the intermediate compound SiP. Thermal analysis technique was applied to study the phase transformations in the alloys at elevated temperatures. It was observed that SiP is melted at 1139 ± 2 °C. A eutectic reaction in the system, in which liquid Si–P alloy is transformed to SiP and a solid solution of P in Si was observed at 1129 ± 2 °C. Moreover, the liquidus and solidus on the silicon-rich part of the phase diagram were determined as:

Solidus: TS = −75.03 CP + 1414 (°C) 0.35 < CP < 1 wt%P

Liquidus: TL = −6.74 CP + 1414 (°C) CP < 6 wt%P

The distribution coefficient of P in Si was calculated as k0 = 0.09 using the obtained solidus and liquidus at low concentrations.

The local structures about Cu, In, and Se atoms in a series of Cu2Se–In2Se3 pseudobinary compounds have been investigated by x-ray absorption fine structure (XAFS). In K-edge XAFS and L3-edge x-ray absorption near-edge structure (XANES) suggest that CuInSe2, Cu0.9InSe1.95, Cu0.82InSe1.91, and Cu2In3Se5.5 have a nominally four-coordinated InSe4 structure, whereas CuIn3Se5 and CuIn5Se8 possess two different InSe4 structures. Cu K-edge XAFS also showed that CuIn3Se5 and CuIn5Se8 possess two different CuSe4 structures, whereas others have a CuSe4 structure. Se K-edge XANES and curve fitting analysis reveal that the Cu vacancy (VCu) gradually forms with decreasing Cu/In ratio. Moreover, the substitution of In for VCu (InCu) is observed in CuIn3Se5 and CuIn5Se8. These results were compared to the previously proposed Cu–In–Se models. We conclude that Cu0.9InSe1.95 and Cu0.82InSe1.91 have a chalcopyrite structure with VCu and that the structure of CuIn3Se5 and CuIn5Se8 is a stannite-like structure with VCu and InCu defects.

In this work, a visible-light-sensitized neodymium complex with 2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine (Dpbt) as a synergetic ligand is synthesized and incorporated into poly(methyl methacrylate) (PMMA). Absorption and luminescent spectra of Nd(TTA)3Dpbt (TTA = thenoyltrifluoroacetonate) in PMMA are measured and compared with common complex Nd(TTA)3Phen (Phen = 1,10-phenanthroline). As a result, Nd(TTA)3Dpbt has relatively high luminescent intensity and wide excited spectral range, attributed to the sensitization of the ligand Dpbt. Judd–Ofelt analysis is used, and Judd–Ofelt parameters are calculated (Ω2 = 33.72 × 10−20 cm2, Ω4 = 11.52 × 10−20 cm2, and Ω6 = 6.81 × 10−20 cm2). The radiative properties are predicted and compared with other different Nd complexes. The stimulated emission cross-section of 4F3/2→4I11/2 transition is 3.02 × 10−20 cm2 and the estimated lifetime is 506 μs using the Judd–Ofelt parameters. Experimental fluorescence branching ratio of this transition is quite high for Nd ions. The radiative properties’ investigation for 4F3/2→4I11/2 transition indicates that it is possible to be a laser transition.

We demonstrate Er3+ diffusivity and solubility increases in off-congruent, Li-deficient LiNbO3 crystal. Li-poor vapor transport equilibration was used to reduce Li2O content in initial congruent crystals. Local Er3+ in-diffusion was then performed in a wet O2 atmosphere. Before and after the Er3+ diffusion procedure, surface Li2O content was evaluated from measured birefringence. The results show that the Er3+ diffusion procedure resulted in 0.3–0.5 mol% Li2O content loss at crystal surface. Secondary ion mass spectrometry was used to measure the Er3+ depth profiles, from which the diffusivity and solubility are determined. It is shown that the Er3+ diffusivity is nearly doubled and the solubility increases at least 0.6 mol% as the Li2O content decreases by 1.0 mol%. From the known Li2O content reduction, the solubility increase is also predicted and the results show that the predicted data are considerably smaller than the experimental results, suggesting that the Er3+ ions occupy also the Nb5+ site, besides the Li+ site.

Ruthenium dioxide (RuO2) was uniformly modified on TiO2 porous thin film by impregnation of Ru-contained dye on the film followed by sintering it at 450 °C to burn off organic matters and form ruthenium oxide, which is named as impregnation method. The homogenous modification of metal oxide inside porous thin film can be realized by the impregnation method, and the modification amount of RuO2 can be easily adjusted by the iteration numbers of impregnation and sintering. Appropriate amount of uniformly modified RuO2 was found to obviously enhance photocatalytic performance of TiO2 to degrade eosin Y. The photocatalysis enhancement was attributed to the shallow hole traps on the surface of nanoparticles formed by RuO2, and these traps can retard recombination of hole with electron.

Following our recent report demonstrating the significance of the nearest-neighbor unlike atom-pair bond in metallic alloys, an equation for the energy of such a bond is presented in this study. The success of empirically derived Miedema’s equation in predicting the signs of the heats of formation of metallic alloys is explained. The negative contribution to the energy stems from the ionicity in the bond. The charge transfer on the bond, suggested by Pauling to establish electroneutrality, contributes the positive term which is quantified in this study. The value of Miedema’s empirically derived constant (Q/P)1/2 and the origin of the R/P term follow from the present model. It is shown that the energy of the atom-pair bond, calculated using the model, in the compounds of MgCu2 structure type are directly correlated to the experimental heats of formation of the compounds, and this fact enables the prediction of the heats of formation values for new compounds of the same structure type.

A one-step wet chemistry route has been explored to synthesize hollow hydroxyl titanium oxalate nanoscale spheres under mild experimental conditions. The hollow spheres were ∼200 nm in diameter, with a shell thickness of ∼30 nm. The nanospheres were formed by smaller aggregated colloidal subunits. The influence of temperature and solvent on the structure of the nanospheres was investigated. The formation of hollow interiors in the nanospheres may be rationalized by Ostwald ripening mechanism. Simple thermal treatment topotactically transformed the chemical composition into anatase TiO2. The high-order hollow porous spherical structure was preserved, with smaller crystalline anatase TiO2 nanoparticles as building units. Dense hydroxyl titanium oxalate nanospheres and their corresponding non-hollow porous anatase TiO2 nanospheres were also successfully achieved in suitable reaction conditions. The method and procedure reported herein may be extended in principle for the fabrication of other functional materials.

Second nearest-neighbor modified embedded-atom method (MEAM) interatomic potentials for the Al–H and Ni–H binary systems have been developed on the basis of previously developed MEAM potentials of pure Al, Ni, and H. The potentials can describe various fundamental physical properties of the relevant binary alloys (structural, thermodynamic, defect, and dynamic properties of metastable hydrides or hydrogen in face-centered cubic solid solutions) in good agreement with experiments or first-principles calculations. The applicability of the present potentials to atomic level investigations of dynamic behavior of hydrogen atoms in metal membranes is also discussed.