The effect of Ag substitution for Cu on the glass forming ability (GFA) and mechanical properties of Mg65Cu25−xAgxGd10 (x = 0, 5, 10, 15, 20, 25) alloyswere investigated using x-ray diffractometry and differential scanning calorimetry.The partial substitution of Cu by Ag in Mg65Cu25Gd10 promoted the GFA. Mg65Cu20Ag5Gd10 bulk metallic glass (BMG) with a diameter of 11 mm could be fabricated by conventional copper-mold casting method in air atmosphere. The Mg65Cu20Ag5Gd10 BMG exhibits yielding and plastic deformation during compressive loading. The compressive fracture strength, total strain to failure, and plastic strain to failure of the Mg65Cu20Ag5Gd10 BMG were 909 MPa, 2.21% and 0.5%, respectively.

A composite material containing uniformly distributed micrometer-sized Nb particles in a Zr-based amorphous matrix was prepared by suction cast. The resulting material exhibits high fractured strength over 1550 MPa and enhanced plastic strain of about 29.7% before failure in uniaxial compression test at room temperature. Studies of the serrations on the stress–strain curves and the shear bands on the fractured samples reveal that the amplitude of the stress drop of each serration step corresponds to the extent of the propagation of a single shear band through the materials. The composite exhibits more serration steps and smaller amplitude of stress drop due to the pinning of shear band propagation by ductile Nb particles.

The structure and dielectric properties of Ca1−xYxTi1−xAlxO3 (CYTA) ceramics prepared by the mixed-oxide route have been investigated. CYTA forms a complete solid solution with an orthorhombic perovskite structure. Residual Y4Al2O9 and Y3Al5O12 resulting from incomplete reaction are observed for ⩾ 0.9. Scanning electron microscopy shows that CYTA ceramics exhibit uniform microstructures, with an average grain size that decreases from ∼200 μm at x = 0 to ∼10 μm at x = 1.0. Transmission electron microscopy of CYTA (x = 0.3) ceramics reveals the presence of ferroelastic domains, and electron-diffraction patterns are indexed on the Pnma space group, consistent with an a+b−b− octahedral tilted structure. The relative permittivity, ϵr, decreases continuously from 170 to 12, while the microwave quality factor, Q·fr, increases from 10,000 to 12,000 GHz, for x = 0 and 1, respectively. CYTA (x = 0.30) ceramics exhibit ϵr ∼ 38, Q·fr of ∼14,212 GHz, and a temperature coefficient of resonance frequency, τf, of −14 ppm/°C. Small additions of acceptor (0.3 wt% ZnO) or donor (1 wt% Nb2O5) dopants decrease Q·fr by ∼20–30%, respectively.

The inner nacreous layer of gastropod mollusc Trochus niloticus is composed of ∼95 wt% planar arrays of polygonal aragonite-based tablets (∼8 μm wide, ∼0.9 μm thick, stacked ∼40 nm apart) and ∼5 wt% biomacromolecules. High-resolution tapping mode atomic force microscope images enabled nanoscale resolution of fractured tablet cross-sections, the organic component, and deformation of individual nanoasperities on top of tablet surfaces. Nanoindentation was performed on individual nacre tablets and the elastic modulus E and yield stress σy were reduced from elastic-plastic finite element simulations yielding E = 92 GPa, σy = 11 GPa (freshly cleaved samples) and E = 79 GPa, σy = 9 GPa (artificial seawater soaked samples). Images of the indents revealed extensive plastic deformation with a clear residual indent and surrounding pileup.

A driver film method, in which a highly stressed overlayer is deposited to de-adhere a target film from a substrate, was developed to study the subcritical debonding behavior of Cu films from glass substrates. The driving force for debonding along Cu/glass interfaces was varied by depositing Cr overlayers to a range of thicknesses. One-dimensional crack growth was achieved by using C release layers and cutting strips from blanket films. Crack velocities, v, were measured and a wide strip solution was developed to obtain strain energy release rates, G. The Cu/Cr strips delaminated in a highly reproducible way, generating v–G plots similar to those seen in stress-corrosion cracking of bulk glass. Small variations in the amount of oxygen incorporated into the films during deposition strongly affected delamination rates. A reaction rate model for subcritical cracking by hydroxylation of the surfaces suggests that changes in oxygen content change the density of strong Cu–O–Si bonds across the interface.

Microstructural changes induced by electromigration were studied in eutectic SnAg solder bumps jointed to under-bump metallization (UBM) of Ti/Cr–Cu/Cu and pad metallization of Cu/Ni/Au. Intermetallic compounds (IMCs) and phase transformations were observed during a current stress of 1 × 104 A/cm2 at 150 °C. On the cathode/substrate side, some of the (Cuy,Ni1−y)6Sn5 transformed into (Nix,Cu1−x)3Sn4 due to depletion of Cu atoms caused by the electron flow. It is found that both the cathode/chip and anode/chip ends could be failure sites. On the cathode/chip side, the UBM dissolved after current stressing for 22 h, and failure may occur due to depletion of solder. On the anode/chip side, a large amount of (Cuy,Ni1−y)6Sn5 or (Nix,Cu1−x)3Sn4 IMCs grew at the low-current-density area due to the migration of Ni and Cu atoms from the substrate side, which may be responsible for the electromigration failure at this end.

Presently, rotational isomeric state (RIS) theory directly addresses polymer chain conformation as it relates to mechanical response trends. The primary goal of this work is to explore the adaptation of this methodology to the prediction of material stiffness. This multiscale modeling approach relies on ionomer chain conformation and polymer morphology and thus has potential as both a predictive modeling tool and a synthesis guide. The Mark–Curro Monte Carlo methodology is applied to generate a statistically valid number of end-to-end chain lengths via RIS theory for four solvated Nafion® cases. For each case, a probability density function for chain length is estimated using various statistical techniques, including the classically applied cubic spline approach. It is found that the stiffness prediction is sensitive to the fitting strategy. The significance of various fitting strategies, as they relate to the physical structure of the polymer, are explored so that a method suitable for stiffness prediction may be identified.

Solid solutions of (Mg4−xMnx)Nb2O9 (MMN), which have a corundum-type structure, showed a single phase over the entire composition range, and lattice parameters of MMN linearly increased with increased composition x. From the calculation of cation–oxygen bonds in NbO6 and MO6 (M = Mg and Mn) octahedra, it was found that the covalency of the Nb–O bond was decreased by the Mn substitution for Mg; the molecular orbital calculation in (NbM12O45)−61 cluster models also revealed that the covalency of the Nb–O bond in the (NbMn12O45)−61 cluster model is smaller than that of the Nb–O bond in the (NbMg12O45)−61 cluster model. This result is attributed to the differences in the density of state, which arise from the overlap population of Mg-3d, Mn-3d, Nb-5s, and O-2p orbitals. The dielectric constant and Q⋅f values varied from 11 to 16 and from 210,000 to 50,000 GHz, respectively. Thus, it is considered that these variations in the microwave dielectric properties may be related to the covalency of the cation–oxygen bonds.

We have characterized thermally annealed perovskite (CaTiO3) surfaces, both before and after aqueous dissolution testing, using scanning electron microscopy, cross-sectional transmission electron microscopy, x-ray photoelectron spectroscopy, and atomic force microscopy. It was shown that mechanical damage caused by polishing was essentially removed at the CaTiO3 surface by subsequent annealing; such annealed samples were used to study the intrinsic dissolution behavior of perovskite in deionized water at RT, 90 °C, and 150 °C. Our results indicate that, although mechanical damage caused higher Ca release initially, it did not affect the long-term Ca dissolution rate. However, the removal of surface damage by annealing did lead to the subsequent spatial ordering of the alteration product, which was identified as anatase (TiO2) by both x-ray and electron diffraction, on CaTiO3 surfaces after dissolution testing at150 °C. The effect of Ca2+ in the leachant on the dissolution reaction of perovskite at 150 °C was also investigated, and the results suggest that under repository conditions, the release of Ca from perovskite is likely to be significantly slower if Ca2+ is present in ground water.

W-rich particle-reinforced Ti-based bulk metallic glass (BMG) matrix composites with a compressive strength approaching 3 GPa and a fracture strain of approximately 12% were developed. In contrast to most existing BMG matrix composites, in which the improved ductility was obtained only at the expense of the strength, the composites developed in this study exhibited a significant enhancement in their strength, as well as an improvement in the plasticity. This improvement in the plasticity was attributed to the blocking and circumscription of the shear band propagation, leading to the formation of a large number of shear bands. Using a classical elasticity theory of inclusions, the improvement of the strength was interpreted as resulting from the generation of tensile residual stresses in the matrix due to the difference in the coefficient of thermal expansion between the W-rich particles and the BMG matrix.

Copper(I) chloride and bromide nanoparticle-dispersed glasses were prepared by means of a conventional copper staining. The staining was performed by the following process: copper stain was applied on the surfaces of Cl−- or Br−-ion-containing borosilicate glasses, and the glasses were heat-treated at 510 °C for various times. Typical exciton bands observed in the absorption spectra of the glasses after the heat treatment indicated that CuCl and CuBr particles were formed in the surface region of the glasses. The average sizes of the CuCl and CuBr particles in the glasses heat-treated for 48 h were estimated at 4.8 and 2.7 nm, respectively. The nanoparticles were also characterized by x-ray diffraction and transmission electron microscopy. Depth profiles of Cu and CuBr concentration in the glass heat-treated for 48 h were measured. Copper decreased in concentration monotonously with depth, reaching up to 60 μm, while the CuBr concentration had a maximum at about 25 μm in depth.

Three lipophilic L-glutamide derivatives with chromophoric head group were synthesized, and their photo-responsive properties were investigated in organic solution systems. By comparing their spectral behaviors, it was shown that organogels underwent a light blue to purple luminescence change, which was triggered by thermally induced monomeric-to-excimeric phase transition. This switching, based on self-assembly, is supposed to have special advantages in molecular electronics.

Hot-forged Ca3Co4O9 (Co349) ceramics were synthesized using large-grained powders prepared by a flux-growth method, and their thermoelectric properties and degree of grain alignment were evaluated. Neutron-diffraction experiments evidenced the effect of grain size on the development of the c-axis grain alignment. The optimum grain size was around 7 μm in our hot-forging method. The electrical resistivity (ρ) in the direction parallel to the pressed-plane was more reduced at higher degrees of orientation. Since ρ was reduced without lowering the Seebeck coefficient (S), the power factor (PF = S2/ρ) of the Co349 sample was improved and reached 0.8 mW/mK2 at 1073 K using Co349 grains with average size of around 7 μm. The thermal conductivity (κ) in the direction parallel to the pressed-plane slightly increased with the increase of the grain size, however the improvement of PF owing to use of large-grained powder outweighed this negative impact on the κ component of the thermoelectric figure of merit (Z = S2/ρκ).

We explored the possibility of incorporating carbon nanotubes in a patterned and macroporous silica structure replicated from a thin polystyrene template. A V-shaped thin, vertical channel was constructed and successfully used to assemble 10.06-μm polystyrene spheres into a dense three-dimensionally ordered template of uniform thickness. Infiltration of a single Co/silica precursor sol into the template followed by thermal treatments in vacuum and H2 produced three-dimensionally ordered silica pores with embedded Co nanoparticles. Wormlike carbon nanofilaments of 50–120 nm in diameter were grown on the inner surface of silica pores with plasma-enhanced chemical vapor deposition.

Thin In2O3:Sn (ITO) films prepared by radio-frequency (rf) or direct-current (dc) magnetron-sputtering and in central or peripheral position relative to the target were characterized by x-ray diffractograms and pole figures. The diffractograms were normalized with the powder diffraction intensities of the target. In the normalized diffractograms, a random texture level and preferred orientations can be distinguished. The pole figures are represented by normalized χ-scans that are modeled as a sum of Gaussian curves. The centers of the Gaussian curves are consistent with the prominent orientations of the normalized diffractograms. The textures of the rf-sputtered films in the central and the peripheral position are similar, showing strong contributions from (211)-planes. The texture of dc-sputtered samples is dominated by (400) and (411) planes. In the peripheral sample, the distribution of (400)- and (411)-oriented grains is shifted towards the incidence angle of the particle flux and the frequency of the (222)-grains is suppressed below the random texture level. The results are discussed with reference to a model of incorporation of interstitial oxygen into the growing films.

The synthesis of efficient ZnTe powder phosphors is very difficult due to its high moisture sensitivity and chemical instability during processing. In this study, an efficient ZnTe:O powder phosphor for x-ray imaging application was successfully synthesized by vacuum firing ZnTe powder prepared from ZnTe bulk crystals ball-milled in an O2 atmosphere. The phosphors were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, photoluminescence, and cathodoluminescence (CL) measurements and found to exhibit a luminescent efficiency three times that of ZnTe:O prepared by ZnO doping. The ZnTe:O samples exhibited a deep red emission centered at 680 nm and a CL decay time of 1.1μs.

Nanocomposite films consisting of gold nanoparticles embedded in an yttria stabilized zirconia (YSZ) matrix were synthesized at room temperature by radio-frequency co-sputtering from YSZ and Au targets at a 5 mTorr working pressure. The films were subsequently annealed for 2 h in 1 atm argon, with the annealing temperature varied from 600 to 1000 °C in steps of 100 °C. The composition, microstructure, and optical properties of the films were characterized as a function of annealing temperature by Rutherford backscattering spectrometry, scanning electron microscopy, Auger electron spectroscopy, x-ray diffraction, and absorption spectroscopy. An optical absorption band due to the surface plasmon resonance (SPR) of the Au nanoparticles was observed around a wavelength of 600 nm. Furthermore, the SPR band full width at half-maximum exhibited an inverse linear dependence on the radius of the Au nanoparticle, with a slope parameter A = 0.18, indicating a weak interaction between the YSZ matrix and the Au nanoparticles. The experimentally observed SPR dependence on nanoparticle size is discussed within the context of the Mie theory and its size-dependent optical constants.

Composites with negative stiffness constituents can exhibit material properties that exceed conventional bounds. Composites with VO2 as negative stiffness inclusions and tin as the stabilizing matrix were prepared via powder metallurgy. Specimens were tested over a range of temperature in torsion using broadband viscoelastic spectroscopy. Composites processed via powder metallurgy exhibited internal friction anomalies over a broad range of temperatures, in contrast to the single, sharp anomalies reported previously from cast specimens. The detailed material behavior encompassed a variety of responses, which were also dependent on the number of thermal cycles. Composite theory predictions assuming a distribution of negative shear moduli can account for peak broadening.

A series of magnetic FeCoNiAl nanocapsules was synthesized by the plasma arc discharge method; the targets of Fe, Co, Ni, and Al powders were changed with varying compositions. The compositions of the nanocapsules were found to be quite different from those of the corresponding targets; the relative amount of Al (or Ni, Co) to Fe was increased (or decreased). Structures, particles sizes, composition, surface composition, magnetic properties, and thermal stability of the nanocapsules were investigated. The saturation magnetization Ms = 106.8 emu/g and coercive force iHc = 367 Oe were achieved for the nanocapsules with the Fe62.5Co21Ni13Al2.5 target. In the FeCoNiAl nanocapsules, the binding energies of Fe, Co, and Ni were different from those of the metals Fe, Co, and Ni. The binding energies of Fe2p3/2 and Fe2p1/2 of the nanocapsules were 708.2 and 721.3 eV, respectively. The four-layer structure was proposed to give a clear statement of how the composition and phase varied radially in the nanocapsules. The major contents of the four layers—i.e., the outer shell, the inner shell, the outer core and the inner core—were amorphous alumina, crystalline alumina, transition metal oxides, and transition metal alloy, respectively. The compositions, structures, particle size, and grain size of the nanocapsules all affect their magnetic properties. In the FeCoNiAl nanocapsules, the greater th amount of the body-centered-cubic phase, the stronger the ferromagnetic magnetic properties.

Bismaleimide polymer composites were coated with adherent, uniform, crack-free, titania films. Selective deposition of either crystalline (anatase) or amorphous films was achieved as a function of deposition conditions. Films are deposited under near ambient conditions from aqueous solution and thus can be adapted to any sample geometry and still provide complete coating of the polymer composite substrate. They can be obtained crack-free in thicknesses up to 0.5 μm by using drying procedures that combine temperature and humidity control.