Ga-doped ZnO (ZnO:Ga) thin films were prepared by radio-frequency–magnetron sputtering on conventional glass substrates at room temperature. The structural, electrical, and optical properties of these films as a function of argon pressure and film thicknesses were studied. All the films crystallized with the hexagonal wurtzite structure. The x-ray diffraction studies show that the ZnO:Ga films are highly oriented with their crystallographic c-axis perpendicular to the substrate. We discuss a methodology of using a “standardized platform” for comparison of samples deposited at different pressures, which provides an insight into the defect–resistivity relationship of each sample with respect to their microstructure. After the first annealing, the electrical properties of the films are dependent on the atmosphere used during postdeposition annealing treatment. A resistivity of 2.5 × 10−3 Ω · cm was obtained after vacuum annealing, and the films became an insulator after air annealing. The reproducibility of this treatment was verified. The average transmittance of all ZnO:Ga thin films is more than 85% in the visible range.

Mechanical alloying of Ti45Zr38–xNi17+x and Ti45–xZr38Ni17+x (0 ≤ x ≤ 8) elemental powders produced an amorphous phase, but subsequent annealing converted the amorphous phase into an icosahedral quasicrystal phase, along with a Ti2Ni-type phase. The discharge capacities, measured in a three-electrode cell at room temperature for both the amorphous and quasicrystal electrodes, increased with increasing Ni substitution for Zr or Ti. The highest discharge capacities, which were about 60 mAh/g for the amorphous electrode and 100 mAh/g for the quasicrystal electrode, were obtained from (Ti45Zr30Ni25) after substitution of Ni for Zr. For the Ti45Zr30Ni25 composition, the discharge performance of the quasicrystal electrode was stable over charge/discharge cycling, but that of the amorphous electrode gradually decreased with cycling. The structure of the quasicrystal phase in the electrodes was stable, even after 15 charge/discharge cycles, but the amorphous phase converted to a (Ti, Zr)H2 f.c.c. hydride.

The influence of shot peening (SP) on high cycle fatigue (HCF) performance of smooth and notched specimens of hot-extruded ZK60 magnesium alloy was investigated and compared to that of hot-extruded and T5 aging-treated ZK60 magnesium alloy referred to as ZK60-T5. The increases in fatigue properties at the optimum Almen intensities were found to depend on the material states. In contrast to ZK60 alloy, higher smooth and notched fatigue properties for both unpeened and peened specimens were observed for ZK60-T5 alloy. Meanwhile, the improvement of fatigue life for notched specimen by SP was much more than that for the smooth specimen. The mechanism by which the compressive residual stress induced by SP resulted in the improvement of fatigue performance of smooth and notched specimens for ZK60 and ZK60-T5 alloys was discussed.

In situ investigation of the interfacial reaction in the Sn/Cu thin film during aging, and reflow was carried out by synchrotron radiation with high intensity and high resolution of x-ray. With this technique, the phase transformation and evolution of the Sn/Cu thin film during heat treatment can be directly and continuously investigated. Moreover, the information for coefficient of thermal expansion in intermetallic compounds was also evaluated by this approach.

In a recent work, Chen et al. [L-Y. Chen et al., J. Mater. Res.24, 3116 (2009)] presented microstructural observation on a plastic Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass (BMG) reported in Liu et al. [Y.H. Liu et al., Science315, 1385 (2007)] by using transmission electron microscopy (TEM) and anomalous small-angle x-ray scattering experiments. Based on their observation, they draw a conclusion that there are no micrometer-sized or nanometer-sized structural heterogeneities in the BMG, and the large plasticity of the BMG cannot be ascribed to the structural heterogeneities. In this comment, we show that their assessment and analysis of their observation are problematic, and it is not evident and precise to use their observation to claim that the BMG is homogeneous and the structural heterogeneity in the glass is an artifact.

A study of the influence of mesoporous SiO2 on the dehydrogenation of NaAlH4 and TiF3-doped NaAlH4 revealed that the amount of hydrogen evolved is 3.8 wt% for the pristine NaAlH4 and around 4.2 wt% for the TiF3-doped NaAlH4, but increases to 4.9–5.0 wt% once the samples are doped with mesoporous SiO2 in the temperature range of 100–350 °C. A favorable synergistic effect on the NaAlH4 dehydrogenation is achieved as mesoporous SiO2 is added as a codopant along with TiF3, which is associated with the nanosized pores and high specific surface area of mesoporous SiO2. The catalytic mechanism of mesoporous SiO2 is more physical than chemical relative to the catalytic mechanism of TiF3.

In this study, the influence of T5 heat treatment on tensile and fatigue behavior of hot-extruded Mg–10Gd–3Y (wt%) magnesium alloy has been investigated. High cycle fatigue tests were carried out at a stress rate (R) of −1 and a frequency of 100 Hz using hour-glass-shaped round specimens with a gauge diameter of 5.8 mm. The results show that fatigue strength (at 107 cycles) of Mg–10Gd–3Y magnesium alloy increases from 150 to 165 MPa after T5 heat treatment, i.e., the improvement of 10% in fatigue strength has been achieved. However, the crack growth resistance is lowered by T5 heat treatment. Results of microstructure observation and scanning electron microscopy-energy dispersive x-ray (SEM-EDX) analysis suggest that the fatigue strength in the Mg–10Gd–3Y magnesium alloy is determined by the threshold stress of basal slip, which is induced by solid solution hardening and precipitation hardening.

Al85Gd8Ni5Co2 metallic glass was subjected to partial devitrification by high-pressure torsion, continuous heat treatment, and isothermal annealing. The fully amorphous alloy exhibits a well-defined transition in its first devitrification product during isothermal heat treatments from τm + α-Al phase mixture to primary α-Al by increasing the annealing temperature above 555 K. This thermal sensitivity predestinates the composition to identify the controversial thermal contribution of the plastic deformation in metallic glasses. Thermal stability and structure of the partially devitrified samples were systematically analyzed and compared by calorimetry, x-ray diffraction, and electron microscopy. It seems that the effect of severe deformation cannot be singled out by a simple isothermal heat treatment; i.e., high-pressure torsion acts as a spectrum of heat treatments performed at different annealing temperatures.

The kinetics of intermetallic compound (IMC) layer and Cu dissolution at Sn1.5Cu/Cu interface under high magnetic field was experimentally examined. It is found that the IMC layer growth is controlled by flux-driven ripening process. The high magnetic field promotes the growth of IMC layer, retards the dissolution of Cu substrate, and decreases the content of Cu solute at the liquid–IMC interface front. Based on the experimental results, it is considered that the magnetization induced by magnetic field promotes the ripening process for IMC layer growth. The Lorentz force dampening the convection and magnetization decreasing the Cu solubility limit can retard the Cu dissolution and change the solute distribution at the liquid–IMC interface front.

The stress relaxation responses of the Sn–3.8Ag–0.7Cu joints following exposure to electrical currents were examined to investigate the effect of electromigration on the reliability of solder joints. It was found that the stress relaxation rate was enhanced for the Sn–3.8Ag–0.7Cu solder joints subjected to a current density of 2 × 104 A/cm2. Sn hillock formation was observed in situ on the surface of the solder joint and the increase of the hillock volume was obtained as a function of the current application time. Analysis of the vacancy flux indicated that the variations of the vacancy concentration with the electromigration time from the calculations agreed with the growth kinetics of the hillocks observed in the experiments. By modeling the stress relaxation as a climb-assisted dislocation glide process, it is shown that the vacancy accumulation induced by electromigration enhanced the dislocation climb rate, resulting in a large increase of the stress relaxation rate.

In this article, palladium modification and silver modification were used as examples to demonstrate the disinfection effects on microorganisms in aqueous environment of photocatalytic transition-metal-ion-modified nitrogen-doped titanium oxide (TiON/M) materials. Transition metal ion modification was applied to TiON to take advantage of the coupling between transition metal ion addition and TiON semiconductor matrix under visible light illumination. The coupling promotes the separation of electron and hole pairs produced by photon excitation, thus it could reduce the intrinsic charge carrier recombination from anion-doping, which largely limits the photoactivity of TiON under visible light illumination. Large enhancements on the hydroxyl radical production and the photocatalytic disinfection efficiency on microorganisms under visible light illumination were observed for TiON with both palladium and silver modifications. The superior photocatalytic performance under visible light illumination suggests that the transition metal ion modification is an effective approach to reduce the massive charge carrier recombination from anion-doping and to enhance the photocatalytic performance of anion-doped TiO2. The resulting photocatalytic materials have the potential for a wide range of environmental applications.

Interatomic potentials are constructed for eight representative binary metal systems covering various structural combinations and thermodynamic characteristics. On the basis of the constructed interatomic potentials, molecular dynamics simulations reveal that the physical origin of metallic glass formation is the crystalline lattice collapsing while solute atoms are exceeding the critical value, thus determining two critical solid solubilities for the system. For a binary metal system, the composition range bounded by the two determined critical solid solubilities is therefore defined as its intrinsic glass-forming range, or quantitative glass-forming ability.

Transparent glass ceramics containing Li2MgSiO4: Cr4+ nanocrystallites were prepared. Intense broadband near-infrared emission with full width at half-maximum larger than 200 nm and long fluorescence lifetime (τ > 100 μs) were observed. The temperature-dependent optical characteristics of the glass ceramics containing Li2MgSiO4: Cr4+ crystallites were compared to those of Li2MgSiO4: Cr4+ single crystals. The reason for extra-long near-infrared fluorescence lifetime was illuminated by the mixed effect between 3T2 and 1E levels. The crystal-filed-induced particular energy-level scheme makes the fluorescence lifetime of the glass ceramics containing Li2MgSiO4: Cr4+ crystallites one order longer than those of other Cr4+-doped glass ceramics.

Three different types of HT-LiCoO2/lithium lanthanum titanate (LLT) assemblies were produced by depositing an HT-LiCoO2 cathode on polycrystalline LLT with various surface finishes, to investigate the effects of the HT-LiCoO2/LLT interface structure on the electrochemical properties of the assemblies. An amorphous layer is confirmed to be introduced by Ar ion irradiation to crystalline LLT. The HT-LiCoO2/LLT assembly composed of the ion-irradiated LLT exhibits good cycle stability and relatively low apparent interface resistivity. These results indicate that the introduction of an amorphous LLT layer by surface modification of crystalline LLT is very effective in improving the structural stability and lithium-ion conductivity of the interface between HT-LiCoO2 and crystalline LLT.

A wet loading method was developed to produce nano-sized LiBH4 combined with nano-SiO2 templates. The multicomponent LiBH4/SiO2 material synthesized by the wet method has been found to dehydrogenate at much lower temperatures than the pure LiBH4, as well as LiBH4/SiO2 mixtures prepared by ball milling. For example, the onset of dehydrogenation was decreased to about 200 °C for a wet-treated LiBH4/SiO2 mixture with a mass ratio of 1:1, and the majority of the hydrogen could be released below 350 °C. The improved dehydrogenation of the wet-treated LiBH4/SiO2 mixtures can be attributed to the destabilization of SiO2, resulting in the formation of lithium metasilicate (Li2SiO3) upon heating, and the confinement of LiBH4 to form nanoscale particles.

The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.

The strain rate dependence of anisotropic compression behavior in porous iron with cylindrical pores oriented in one direction was investigated. Through high strain rate (˜103 s−1) compression tests along the orientation direction of pores using the split Hopkinson pressure bar method, it was shown that the stress–strain curve exhibits a unique plateau-stress region where deformation proceeds with almost no stress increase. The appearance of the plateau-stress region is related to the buckling deformation of the iron matrix and provides superior energy absorption. However, for the middle (˜10−1 s−1) and low strain rates (˜10−4 s−1), compression along the same direction produces no such plateau region. In fact, in contrast to compression in the parallel direction, compression perpendicular to the orientation direction of pores produces no plateau-stress regions in any of the three strain rates.

We report dye-degradation effects of a semiconductor LiBiO3 revealed under illumination of a conventionally used white fluorescent light. Optical absorbance spectra of LiBiO3 were broadened so smoothly, with the absorption edge penetrated to around 730 nm, that the material was able to absorb a wide range of visible light. Results showed that solution of a standard dye, methylene blue, was degraded completely after 4 h illumination. Furthermore, the value of total organic carbon decreased 70% in the decolorized solution, suggesting that the molecular form of the original methylene blue was mineralized effectively to nonorganic fragments by the photoinduced oxidization effect. Moreover, the wavelength dependence of apparent photonic efficiency was evaluated using a standard Xe lamp coupled with monochromatic filters. These results were interpreted from the viewpoint of this material’s electronic structure.

The compositional dependence of glass formation and thermal and elastic properties was clarified for the ternary La–Al–Co bulk glass-forming system. The existing linear correlation between La concentration and characteristic temperatures, i.e., the glass transition temperature Tg and the onset temperature of crystallization Tx, as well as the elastic moduli in this system can give a useful guideline for the chemical design of desirable bulk metallic glasses (BMGs) with tunable physical properties in advance. The relationship between Tg and elastic constants for the La–Al–Co BMGs can be quantitatively described using a microscopic model proposed by T. Egami.

An improvement of the fatigue resistance of rolled AZ31 magnesium alloy was attempted by reducing the tensile mean stress developed during fatigue deformation, which was achievable by tailoring the {10-12} twinning-detwinning characteristics of the material through the precompression process. The modification of the {10-12} twinning-detwinning characteristics made it possible to control the plastic deformation mechanisms activated during fatigue deformation so that the imposed tensile strain could be fully accommodated by detwinning alone, which led to a significant reduction of tensile flow stress, finally resulting in the reduction of mean stress.