To optimize the structure of the flexible piezoresistive sensor based on conductive polymer composite and widen the workable pressure range, a piezoresistive sensor with a multilayered structure based on carbon nanotubes/carbon black/silicone rubber conductive composite was designed and investigated. Different from the traditional monolayer structure, this novel multilayered sensor consisted of three microstructured piezoresistive composite films. The experimental data showed that the electrical resistance of the sensor varied regularly with a wide range of applied pressure (0–1.8 MPa at least). The high sensitivity, high flexibility, facile fabrication, and low cost were also the advantages of this pressure sensor. In addition, the piezoresistive mechanism was studied and shown to be the synergistic effects of the contact resistance mechanism and bulk resistance mechanism. Factors influencing the piezoresistive properties were also investigated. Moreover, the consecutive loading tests verified the feasibility and stability to use this sensor element for pressure measurement.

A model of reactive hot pressing of zirconium carbide (ZrCx, 0.5 < x < 1) has been constructed that incorporates four processes that occur in parallel: creep of zirconium (Zr), reaction of Zr and carbon (C), increase in volume fraction of hard phase with progressive reaction that reduces the creep of Zr and, finally, de-densification associated with volume reduction during reaction. The reasonable agreement of the model with experimental results verifies that plastic deformation of Zr is the main factor that is responsible for the low-temperature reactive densification of ZrC and that ZrC may be treated as a rigid inclusion that contributes little to densification. It predicts that densification is impaired by increasing carbon stoichiometry due to the increasing amount of starting hard phase and the greater contraction upon reaction. Additionally, the model predicts that mixtures of Zr and ZrC should show equal or better densification than Zr and C mixtures.

Rutile nanoparticles have been synthesized by acid hydrolysis of titanium isopropoxide by low-temperature dissolution-reprecipitation process. High-resolution transmission electron micrographs of the rutile colloidal solution show needle-shaped rutile nanoparticles with the dimensions of 10–30 nm in diameter and 100–150 nm in length. X-ray diffraction (XRD) data show the existence of only the rutile polymorph in TiO2 powder with a crystallite size of 11.3 nm. The dielectric constant of rutile nanoparticles has been found to be 57 at 10 MHz AC frequency and DC conductance as 2.3 × 10−6 S/cm. Transmission electron micrographs and XRD data analysis imply that the rutile crystallites are self-organized in a regular fashion to produce multilayer three-dimensional linear clusters. The clusters have been found to be microporous (average porosity 1.4 nm) with high specific surface area (132.2 m2/g). At higher concentration, the clusters aggregate to produce interconnected network of star- or flower-like structures. This organized crystalline microporous metal-oxide semiconductor might find various practical applications.

We report on the study of the characteristics of indium–tin oxide (ITO) films prepared by well-controlled and reproducible DC magnetron sputtering in argon with consequent annealing in oxygen atmosphere. The structural, electrical, and optical properties of the ITO films were investigated. It was found that the films deposited in argon atmosphere with a commercial ITO target have low transparency and high resistivity. The lower value of the resistivity around 3 × 10−4 Ω cm and the higher value of the figure of merit of 7.4 × 10−3 Ω−1 for 200 nm thick films are obtained after postannealing the films at the optimal temperature T = 300 °C for 1 h. It was found experimentally that postannealing at different temperatures allows tuning effective work function of the ITO films in the range of 4.2–5.5 eV. The latter is an important issue for applications in optoelectronic devices. The fabrication method is useful for the fabrication of ITO films with high electro-optical parameters on flexible polyimide substrates.

In this paper, the Ni-decorated ZnO photocatalysts with magnetic separable characteristics were prepared by a simple replacing-hydrothermal process for the first time. The as-synthesized composites were characterized by powder x-ray diffraction, UV–visible diffuse reflectance spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscope, transmission electron microscopy, and so on. It is found that the introduction of Ni (as Ni0 and Ni2+ forms) turned the morphologies of ZnO photocatalysts, enhanced photoabsorption in a visible light region, and increased amount of surface adsorbed oxygen. The photodegradation test of anthraquinone dye (reactive brilliant blue KN-R) indicated that the Ni-decorated ZnO photocatalysts have better activities as compared to the ZnO reference. The enhancement of photocatalytic activity of Ni-decorated ZnO photocatalysts can be attributed to the existence of Ni2+ doping, Ni0/ZnO heterostructure, and abundant-adsorbed oxygen (as the electronic scavenges), which caused efficient separation of electron–hole pairs in Ni-decorated ZnO photocatalysts. Furthermore, the introduction of metallic Ni also endued ZnO with good magnetic recoverability. The re-collected experiments by external magnetic field indicated that Ni-decorated ZnO as a magnetically recoverable photocatalyst is acceptable.

Metallic zinc nanoparticles are generated in two compositional ranges of borosilicate glasses upon 200 and 300 keV electron beam irradiation in a transmission electron microscope. Irradiation effects are studied either with a stationary electron beam as a time series or with spatially varying beams for line-scan patterning. The size of the zinc nanodots formed is inversely related to the distance from the center of the electron beam, and growth from 5 to 50 nm over time via ripening can be observed. Line-scan patterning via both thermal gun and field emission gun electron irradiation has been successfully achieved. Our findings also show the occurrence of self-organized particle ordering, such as formation of chains. Metal nanoparticles have a tendency to migrate toward the glass fragment center, unless high intensity radiation ablates the glass matrix, when Zn particles remain decorating the surface. High-resolution lattice imaging, scanning transmission electron microscopy, and electron energy loss spectroscopy are used to confirm particle identity.

The growth kinetics of gold nanoparticles (NPs) during the reduction of HAuBr4 by hydrazine in the reverse micelles of oxyethylated surfactant Tergitol NP 4 was studied in situ by UV–vis spectroscopy. Kinetic mechanism includes the steps of slow, continuous nucleation and fast, autocatalytic surface growth. Both steps are under kinetic control of the precursor reduction. The rate of nucleation is limited by reaction in the droplets of the aqueous phase forming the cores of reverse micelles, and growth rate is limited by the reaction on the surface of gold NPs growing inside the micelles. The chemical mechanism of reduction of halogenated forms of gold AuX4– by hydrazine is the same in the case of X = Cl, Br and includes the equilibria of formation and redox decomposition of the intermediate complexes AuIII(N2H4)X3 and AuI(N2H4)X. The initial form of AuX4– (X = Cl, Br) does not affect the size of the final NPs synthesized in micellar solution of oxyethylated surfactant.

The study reports the functionalization of the size-controlled synthesized silver nanoparticles (AgNPs) with coumarin derivative. The size and the morphology of the as-synthesized AgNPs were obtained in the presence of glycerol and sodium citrate which acted as the reducing agent which led to nucleation of silver ions thus yielding different sizes of AgNPs. The obtained AgNPs were functionalized with different stoichiometric ratios of [HS-(CH2)11-NHCO-coumarin:HS-PEG-(CH2)11COOH] to form mixed monolayer protected silver clusters and their Raman activities were evaluated to determine the effect of particle size on the enhancement factor (EF). The functionalization and the stability of AgNPs were confirmed using a combination of techniques, namely UV–Visible spectroscopy, transmission electron microscopy, Zetasizer, and Raman spectroscopy. The obtained Raman spectra were used to calculate the EF of the HS-(CH2)11-NHCO-coumarin adsorbed on AgNPs, which was observed to increase with an increase in size of AgNPs from 16 to 30 nm. Increasing the particle size to 43 nm lowered the EF by 10-fold and hence an optimal size of ∼30 nm was achieved for the coumarin derivative adsorbate.

Cu90Ag10 alloys were subjected to severe plastic deformation at temperatures ranging from 25 to 400 °C and strain rates ranging from 0.1 to 6.25 s−1 using high-pressure torsion. The deformed samples were characterized by x-ray diffraction, transmission electron microscopy, and atom-probe tomography. A dynamic competition between shear-induced mixing and thermally activated decomposition led to the self-organization of the Cu–Ag system at length scales varying from a few atomic distances at room temperature to ≈50 nm at 400 °C. Steady-state microstructural length scales were minimally affected by varying the strain rate, although at 400 °C, the grain morphology did depend on strain-rate. Our results show that diffusion below 300 °C is dominated by nonequilibrium vacancies, and by comparison with previous Kinetic Monte Carlo simulations [D. Schwen et al., J. Mater. Res.28, 2687–2693 (2013)], their concentration could be obtained.

The fracture toughness values of nanosized Cu and Ni single crystals with an edge nanocrack were determined under quasi-static loading conditions. Molecular statics (MS) simulations that can essentially capture the discreteness and the nonlinearity of materials were used in the present study. Different crack lengths were used to evaluate the effects of crack size on the fracture toughness. Based on MS simulations, the energy release rate was calculated using the energies obtained from two models with neighboring crack lengths under the same loading conditions. Furthermore, continuum counterparts of the atomistic models were used to calculate the toughness by the finite element method for linear elastic fracture mechanics (LEFM). The reasons behind the discrepancies between the toughness values obtained using different methods were discussed, and the applicable ranges of the toughness and the LEFM were indicated in terms of the lattice constants.

To investigate the effect of Y element and hot-extrusion on microstructure and mechanical properties of the three alloys which are Mg–4Zn–xY (x = 1, 2, 3 in wt%). All the three alloys are hot-extruded and analyzed. The results show that as Y is increased, the microstructures of the as-cast alloys are more refined and the phase compositions are changed from both I-phase and W-phase to single W-phase whose structure is changed from mix of net and spheroidization to continuous net. The mechanical properties are increased to a small extent mainly due to the refining effect of Y. After hot-extrusion, coarse dendrite crystals are broken and dynamic recrystallization appears which obviously refine the microstructure. Second phases are redistributed along the extrusion direction. W-phases are twisted and broken, while I-phases are spheroidized. Tensile strengths and elongations are all increased by around 100% compared with the as-cast alloys.

This paper details an investigation into the effect of martensite–austenite (M–A) constituent on impact toughness of intercritical heat-affected zone (IC HAZ) in Q690 steel, a low carbon bainitic steel. Large samples with uniform microstructure similar to that of the actual IC HAZ were achieved through combinations of heat treatments. The samples were heated to temperature between 750 and 830 °C for 30 min and then quenched in water. After these heat treatments, hard martensite islands distribute along the boundaries of soft matrix, and the size of martensite islands increases with heating temperature. The microstructure is quite similar to that of the IC HAZ. Using these large samples, the impact toughness could be measured conveniently. It was found that the embrittlement of the IC HAZ depends on the deformability and size of the M–A constituent. When the size of the M–A constituent whose deformability is low exceeds a critical value (2.0 μm), the embrittlement of the IC HAZ occurs.

In molecular dynamics simulations, the local stress state in the shear band is examined in six different model metallic glasses and one amorphous Si system (also has been perceived as a metallic glass analog) under different loading conditions. For all but the FeP and the amorphous Si systems, the running shear band (RSB) exhibits a liquid-like hydrostatic plus shear stress state. Our results suggest that the liquid feature of a RSB is not due to temperature rise or plastic confinement but due to the disorder driven by flow, which can be offset by strong directionality in bonding, phase segregation, or aging. The knowledge of the liquid-like stress state can be conveniently utilized in experiments to infer the local stress state of the RSB from the global tensile stress for metallic glasses.

The present study was conducted to predict the hot deformation behavior of the as-forged Nitinol 60 shape memory alloy by using the Arrhenius type, multiple-linear, and artificial neural network (ANN) models. The acquired flow stress data from isothermal hot compression tests in a temperature range of 650–850 °C under strain rate range of 0.01–1 s−1 were used to calculate the material constants for establishing the corresponding constitutive equations. Furthermore, a comparative study has been made on the capability of the aforementioned models to predict the high-temperature deformation behavior by comparing the prediction relative errors, average absolute relative error, and correlation coefficient. The results show that multiple-linear model predicts the flow behavior more accurately than the Arrhenius type model. The ANN model is much more efficient and has a better prediction power for the as-forged Nitinol 60 alloy than both the Arrhenius type and multiple-linear models.

Model Fe–9Cr–xMo alloys with high Mo content alloys were cast to investigate the effect of Mo on the phase evolution and properties of the alloys. The Mo contents in the alloys were 5, 7, and 9 wt%, while the Cr content was held constant at 9 wt%. For comparison, a commercial A213T 9-P9 (Fe–9Cr–1Mo) alloy, widely used in the petrochemical industry, was also investigated. The alloys were heat-treated at temperatures between 450 and 650 °C and characterized by scanning electron microscopy, x-ray dispersive energy spectroscopy, and electron backscatter diffraction. Potentiodynamic linear polarization technique was used to evaluate the corrosion of the alloys in a 0.5 mol L−1 H2SO4 solution containing 0.1 mol L−1 NaCl. The results showed that the corrosion resistance of the alloys was affected by precipitation of the µ phase and that the Mo content in excess of 5% is deleterious to the corrosion resistance of the Fe–Cr–Mo alloys.