A new method to accurately and reliably extract the actual Young's modulus of a thin film on a substrate by indentation was developed. The method involved modifying the discontinuous elastic interface transfer model to account for substrate effects that were found to influence behavior a few nanometers into a film several hundred nanometers thick. The method was shown to work exceptionally well for all 25 different combinations of five films on five substrates that encompassed a wide range of compliant films on stiff substrates to stiff films on compliant substrates. A predictive formula was determined that enables the film modulus to be calculated as long as one knows the film thickness, substrate modulus, and bulk Poisson's ratio of the film and the substrate. The calculated values of the film modulus were verified with prior results that used the membrane deflection experiment and resonance-based methods. The greatest advantages of the method are that the standard Oliver and Pharr analysis can be used, and that it does not require the continuous stiffness method, enabling any indenter to be used. The film modulus then can be accurately determined by simply averaging a handful of indents on a film/substrate composite.

An n-body potential is first constructed for the Zr–Al system and proven to be realistic by reproducing a number of important properties of the system. Applying the constructed potential, molecular dynamics simulations, chemical short-range order (CSRO) calculation, and Honeycutt and Anderson (HA) pair analysis are carried out to study the Zr–Al metallic glasses. It is found that for the binary Zr–Al system, metallic glasses are energetically favored to be formed within composition range of 35–75 at.% Al. The calculation shows that the CSRO parameter is negative and could be up to −0.17, remarkably indicating that there exists a chemical short-range order in the Zr–Al metallic glasses. The HA pair analysis also reveals that there are diverse short-range packing units in the Zr–Al metallic glasses, in which icosahedra and icosahedra/face-centered cubic (fcc)-defect structures are predominant.

We investigated the structural stabilities of the intermetallics and the solid-state phase transformations induced by lattice vibration effects in the Al–Zr system by first-principles calculations. The calculated lattice parameters of all the phases and the phonon dispersion relations for pure Al and Zr are in good agreement with the experimental data. AlZr(oC8), Al4Zr5 (hP18), and Al3Zr5 (tI32) are predicted to be the high-temperature phases. To study the structural stabilities at high temperatures, the thermodynamic properties of the intermetallics are calculated via the linear response approach within the harmonic approximation. Thanks to the calculated enthalpies of formation at high temperatures, Al3Zr5 is predicted to be stabilized above 1163 K with respect to AlZr2 and Al2Zr3, in good agreement with the phase transformation temperature (1273 K) in the experimental phase diagram.

Trace additions of boron to cast zirconium result in significant microstructural changes similar to those observed with additions of boron to titanium alloys. These changes include the promotion of dendritic growth and a refinement in both the prior β and α grain size. The refinement of the prior β grain size is explained using a model of grain refinement in association with values calculated from the binary Zr–B phase diagram. It is proposed that the refinement of the α phase occurs through a combination of increased nucleation and altered diffusion mechanisms during cooling through the β transus.

Structural origin of the high glass-forming ability (GFA) in multicomponent bulk metallic glasses (BMGs) caused by minor alloying was investigated using state-of-the-art synchrotron radiation techniques. It is found that a two-shell icosahedral cluster with one Y center is the basic structural unit in the representative Cu46Zr42Al7Y5 BMG, which may be densely packed with the help of shared and glue atoms, leading to enhanced ordering at short and medium range. This cluster dense packing may play a key role in achieving the high GFA in CuZrAlY alloy, which also explains the strong dependence of GFA on Y content observed in many experiments. The present work may be extended to a series of multicomponent amorphous alloys, the formation of which is strongly dependent on minor alloying.

This work first deals with the effect of Nb addition on the liquid phase separation in the Cu–Co system, which displays a metastable liquid miscibility gap. The isothermal sections at 800, 900, 1000, 1100, and 1200 °C in the Cu–Co–Nb system have been experimentally determined by optical microscopy, electron probe microanalysis, and x-ray diffraction on the equilibrated alloys, and the phase equilibria in the Cu–Co–Nb ternary system were thermodynamically assessed by using CALPHAD (Calculation of Phase Diagrams) method on the basis of the presently determined experimental data. Nb additions can stabilize the metastable liquid phase separation in the Cu–Co binary system and significantly increase its critical temperature. The solidified Cu–Co–Nb alloys appearing on the top-bottom separated microstructural morphology under low cooling rate while forming core-type macrostructural morphology under high cooling rate have been confirmed.

The distribution of alloying elements and the corresponding structural evolution of Mn–Sb alloys in magnetic field gradients were investigated in detail. It was found that a high magnetic field gradient could control the distribution of solute element in the alloys during the solidification process and therefore resulted in the coexistence of both primary MnSb and Sb phases or the aggregation of the primary MnSb with a continuous change in morphology. The positions where these primary phases located depended on the direction of field gradient. The control of the solute element distribution by a high magnetic field gradient was realized through the magnetic buoyancy force that could drive the migration of Mn element in the melt, originating from the difference in the magnetic susceptibility between Mn and Sb. The effectiveness of this control depends on the alloy composition, specimen dimension, cooling rate, and |BdB/dz| value.

The asymmetrical hysteresis loops were observed for the annealed Fe65Co15Si5B15 amorphous ribbons. The curves, which shift from the zero point of H axis with a unilateral step magnetization, exhibit the special magnetic features of the ribbons. A few magnetic crystalline phases were identified in the amorphous matrix of annealed ribbons by microstructure measurement. It was also found that the Z-oriented local magnetic domains emerge in the surface of ribbons with the loops shift behavior. Subsequent magnetic torque measurement indicated that the unidirectional magnetic anisotropy was induced in the amorphous ribbons with proper thermomagnetic annealing. These obtained evidences support our understanding that the magnetic history caused by thermomagnetic treatment plays a main role in promoting the formation of the asymmetrical loops.

Two laser processes, flat plate ablation (FPA) and laser ablation of microparticle aerosols (LAMA), capable of producing nanoparticles and nanoparticulate thick films of Terfenol-D (Fe1.92Tb0.3Dy0.7) were investigated. The influence of processing parameters on the sizes, compositions, and morphologies of the nanoparticles produced using these processes were studied by transmission electron microscopy. The nanoparticles were used to deposit nanoparticulate films by supersonic impaction with thicknesses ranging from 4 to 50 μm, depending on processing conditions. The microstructures and properties of the films were studied using scanning electron microscopy and magnetometry. The LAMA process produced nanoparticles with a mean size and standard deviation (SD) of 8 to 10 nm ± 5 nm, depending on the type of gas used during synthesis. In contrast, nanoparticles produced using the FPA process exhibited a much broader size distribution varying from 5 to 150 nm and a much greater variation in compositions compared to the LAMA process. Films produced using LAMA also had lower levels of porosity compared to those produced using FPA as a result of the smaller, more uniform nanoparticles from which they were produced and the resulting higher impaction velocities. Compared to the FPA-produced films, the LAMA-produced films exhibited greater resistance to oxidation, higher magnetizations (13–15 emu/g versus 9–11 emu/g, depending on processing conditions) and lower coercivities (versus 41–59 Oe versus 80–110 Oe).

Tight networks of interwoven carbon nanotube bundles are formed in our highly conductive composite. The composite possesses properties suggesting a two-dimensional percolative network rather than other reported dispersions displaying three-dimensional networks. Binding nanotubes into large but tight bundles dramatically alters the morphology and electronic transport dynamics of the composite. This enables it to carry higher levels of charge in the macroscale leading to conductivities as high as 1600 S/cm. We now discuss in further detail, the electronic and physical properties of the nanotube composites through Raman spectroscopy and transmission electron microscopy analysis. When controlled and used appropriately, the interesting properties of these composites reveal their potential for practical device applications. For instance, we used this composite to fabricate coatings, which improve the properties of an electromagnetic antenna/amplifier transducer. The resulting transducer possesses a broadband range up to GHz frequencies. A strain gauge transducer was also fabricated using changes in conductivity to monitor structural deformations in the composite coatings.

Co/MnO2 particles are synthesized by a simple two-step chemical process. It includes the reduction of Co2+ cations to Co nanoparticles with sodium borohydride (NaBH4) in aqueous solution, followed by coating the sample with a surface layer of MnO2. The coating is accomplished using a simple decomposition reaction, in aqueous KMnO4 solution with acid environment at room temperature. Transmission electron microscopy (TEM) analysis demonstrates that the core of the particles is composed of Co clusters that have a narrow size distribution. The strong interface effect of the Co/MnO2 particles is also studied by the detection of exchange bias phenomena of hysteresis curves.

Flowerlike submicrometer gold particles were synthesized through a simple one-step method using p-diaminobenzene as a reductant in the presence of poly(sodium 4-styrenesulfonate) in aqueous solution. The particle size with diameters ranging from 267 to 725 nm could be tuned by varying the molar ratio of poly(sodium 4-styrenesulfonate) to HAuCl4, which also resulted in tunable roughness. The gold particles were confirmed by scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. Cyclic voltammetry showed that the specific surface area of the flowerlike particles was larger than that of sphere particles. The obtained flowerlike particles with higher surface area also exhibited higher electrocatalytic activity toward H2O2 and O2. The increase of electrocatalytic activity could be attributed to the increase of the active surface area.

This paper reports the development of nonwoven nanofibers of pure and iron-doped titanium dioxide (TiO2) and evaluation of their antimicrobial attributes for using them as disinfectant gauze for wound healing upon brief activation by ultraviolet/infrared (UV/IR) illumination. It was found that the fibers exhibited superior bactericidal affinity when exposed briefly (3–12 s) to either multiphoton laser or infrared radiations. On the other hand, exposure to a UV beam for up to 20 min was not effective in mitigating the bacterial colonization of the Escherichia coli.

The synthesis of hexagonal aluminum nitride (AlN) nanoparticles and nanowhiskers by using direct nitridation of aluminum powders is presented in this work. After mixing aluminum powders with carbon and silica (derived from rice bran ashes) at a cryogenic temperature, the homogeneous mixture was heat treated/examined in a differential scanning calorimeter/tube furnace under N2 atmosphere. Under a maximum temperature of 1450 °C in N2 atmosphere, the as-milled aluminum-carbon-silica powder mixtures transformed completely into AlN nanoparticles and nanowhiskers with a trace of graphite. The formation mechanisms for AlN nanoparticles and nanowhiskers are discussed.

We demonstrated the growth of indium nitride (InN) nanowires on Si(111) substrates by metalorganic chemical vapor deposition without the use of any intermediate GaN or AlN buffer layer. The InN nanowires were grown by forming the Au + In droplets and In droplets on the Au- and In-coated Si substrate. The growth conditions such as chamber pressure, chamber temperature, reaction gas flow rate, and carrier gas flow rate were optimized to yield nanowires free from contamination. Depending on the growth parameters different growth regimes for the InN nanowires were identified. The strength of self-catalytic route has been highlighted. The morphology and microstructures of samples were characterized by x-ray diffraction and scanning electron microscopy (SEM). The transmission electron microscopy and SEM investigations showed that the InN nanowires are single crystals with diameters ranging from 40 to 400 nm, and lengths up to 3 µm. Photoluminescence spectra of the InN nanowires showed a strong broad emission peak at 0.77 eV.

The dependence of the dielectric properties on the uniaxial compressive stress and the stress-strain properties was investigated for the case of (1-x)Na0.5Bi0.5TiO3–xNaTaO3 ceramics. Special attention was focused on the time component and the reversibility of the permittivity–stress dependence. The results were interpreted according to the samples' polar and symmetry states and the ferroelasticity. The time dependence and irreversible changes of the dielectric properties were connected with the domain structure of the materials, which is modified under the applied stress. The irreversible changes observed in the macroscopically nonferroelectric compositions were related to the ferroelastic properties. The stress sensitivity increased with the addition of NaTaO3 from 3% in pure Na0.5Bi0.5TiO3 to 14% in the sample with 15 mol% of NaTaO3 (at 200 MPa and 1 MHz). The reversibility was improved by mechanical modification of the samples' domain state, while the dielectric response remained time dependent.

The influence of BaCu(B2O5) (BCB) addition on the sintering temperature and microwave dielectric properties of Ba5Nb4O15 ceramics has been investigated. The addition of small amount of BCB can effectively lower the sintering temperature of Ba5Nb4O15 ceramics from 1400 to 875 °C and induce no obvious degradation of the microwave dielectric properties. The reduced sintering temperature was attributed to the BCB liquid phase. Typically, the 1.5 wt% BCB-added Ba5Nb4O15 ceramic sintered at 875 °C for 2 h exhibited good microwave dielectric properties of Q × f = 28,655 GHz, εr = 40.2, and τf = 60 ppm/°C. The dielectric ceramic demonstrated stability against the reaction with the Ag electrode, which suggests that the ceramics could be applied in multilayer microwave devices requiring low sintering temperatures.

The structural, transport, and magnetotransport properties of single-phase, homogeneous nanostructured La0.7Sr0.3MnO3 (LSMO) manganites synthesized by the coprecipitation route were investigated and the effect of sintering temperature on the microstructure of LSMO compounds was studied. A strong dependence of transport and magnetotransport behavior on the microstructure and nature of grain boundaries has been observed in the single-phase LSMO sintered at various temperatures. High-field magnetoresistance (HFMR) at room temperature is found to increase [13% (LS6) to 25% (LS9)] while low temperature (5 K) magnetoresistance decreases [75% (LS6) to 46% (LS9)] under 9 T field with increase in sintering temperature, which has been attributed to the spin-polarized tunneling and spin-dependent scattering of charge carriers.

Ni0.8Zn0.2Fe2O4/Ba0.6Sr0.4TiO3 (NZO/BST) composites with high permittivity and low loss were synthesized via the hybrid processing route. The composites possess very dense and homogenous microstructure. The NZO/BST composites show good dielectric properties and magnetic properties with low loss in high frequency range. This indicates that this kind of magnetodielectric composites can be used in high-frequency communications for the capacitor-inductor integrating devices such as electromagnetic interference filters and antennas. The permittivities of the composites were also fitted using the combination of Maxwell–Wagner polarization and modified Curie–Weiss law.

Solid solutions 0.7Bi1−xLax (Fe0.9Cr0.1) O3–0.1BaTiO3–0.2PbTiO3 (BLxFOC-BT-PT, with x = 0, 0.03, 0.05, 0.07) solid solutions were prepared by the traditional ceramic process. X-ray diffraction results reveal that all samples show pure pseudocubic perovskites structure. The lattice parameter of the solid solutions increases linearly with the La content, indicating that La ions have entered crystal lattices to form a solid solution. The Curie temperature of the solid solutions decreases with the La content. Room-temperature polarization–electric field (P–E) curves indicate that the samples with x = 0.03 and 0.05 exhibit saturated P–E loops. Piezoelectric constant d33 of the solid solutions increases firstly and then decreases. Magnetizations of the solid solutions decrease with the La content. The evidence of weak ferromagnetism and saturated ferroelectric hysteresis loops in BLxFOC–BT–PT system at room temperature makes it a good candidate for multiferroic applications.