We investigate the effect of dopant species and structure on the thermal conductivity of Sb-doped SnO2 (ATO) and Ta-doped SnO2 (TTO) films and compare the results with those of In2O3-, ZnO-, and TiO2-based transparent conductive films. The thermal conductivities (λ) of polycrystalline ATO and TTO films are 4.4–4.9 and 4.7 W m−1 K−1, respectively. The thermal conductivities via phonons (λph) are almost identical for both dopant species (Sb and Ta): 4.3 and 4.5 W m−1 K−1 for Sb and Ta, respectively, on average. These results for λph are larger than that for Sn-doped In2O3 films (3.8 W m−1 K−1) and considerably larger than that for amorphous ATO films (1.0 W m−1 K−1). These facts lead us to conclude that the base-material species (SnO2 or In2O3) and structure (polycrystalline or amorphous) affect the thermophysical properties of ATO and TTO much more than the dopant species.

In this review, we discuss the recent developments of high-performance and improved-stability of indium-oxide-based transparent amorphous-oxide semiconductor (TAOS) thin-film transistors (TFTs) properties. TAOSs are widely explored with the aim of producing high-performance semiconductors suitable for the channel layer of TFTs which enable to survive under light and thermal-bias-induced stress conditions. Numerous TAOSs have been invented with some improved performance characteristics of TFTs such as mobility, light and thermal induced bias stress. However, there has been no clear elucidation of the mechanisms driving these improvements. In this review, we discuss the progression of innovations of high performance indium-oxide-based TAOS TFTs from its first reported amorphous indium gallium zinc oxide (a-IGZO) to present, and their properties that are correlated with the Lewis acid strength (L) and bonding strength of dopant and oxygen as a carrier suppressor and strong binder. The proposed mechanism can be practical to develop novel TAOS TFTs with high mobility and stability.

Extension of microelectromechanical systems (MEMS) into more extreme operating conditions will require a wider range of material properties than are currently available in conventional systems. Successful integration of new materials is dependent on concurrent development of compatible fabrication routes and scale appropriate evaluation techniques. This review focuses on emerging material classes that have potential to replace silicon-based MEMS in elevated temperature applications. Basic silicon mechanical properties and micromachining methods are reviewed to provide context for developing material systems such as silicon carbide, silicon carbonitrides, and several nickel-based alloys. Potential improvements in strength, thermal stability, and reliability are juxtaposed with fabrication, reproducibility, and economic feasibility issues that must also be addressed.

Ytterbium monosilicate (Yb2SiO5) is a promising candidate for environmental barrier coating. However, its mechanical and thermal properties are not well understood. In this work, the structural, mechanical, and thermal properties of Yb2SiO5 are studied by combining density functional theory and chemical bond theory calculations. Based on the calculated equilibrium crystal structure, heterogeneous bonding nature and distortion of the structure are revealed. Meanwhile, the full set of elastic constants, polycrystalline mechanical properties, and elastic anisotropy of Yb2SiO5 are presented. In addition, the minimum thermal conductivity of Yb2SiO5 was determined to be 0.74 W m−1 K−1. The theoretical results highlight the potential application of Yb2SiO5 in a thermal and environmental barrier coating.

In this paper, high-k hafnium–aluminum oxide (HAO) films were synthesized by the sol–gel technique. The effects of the ratio of Hf and Al on the properties of the HAO films were investigated thoroughly. The average optical transmittance of the HAO films was above 88% within the visible light range and Al incorporation in HfO2 can enlarge the band gap of HAO films. X-ray diffraction (XRD) results showed that Al additive can suppress the crystallization of HfO2 and the HAO films were amorphous in structure. The refractive index of HAO films can be modulated with the ratio of Hf and Al in the HAO films. The HAO films with the ratio of Hf and Al = 2:1 obtained excellent performance including the root mean square (RMS) roughness of 0.26 nm, the relative permittivity of 12.1, the leakage current density of 1.69 × 10−7 A/cm2 at 2 MV/cm, and the etching rate in dilute HF solution less than 1 nm/s.

Plate-shaped Gd2O3 nanoclusters (GNCs) with well-controlled loading were fabricated by using amphiphilic poly(maleic anhydride-alt-1-octadecene) (PMAO) grafted with PEG as nanogel. The hydrodynamic size of the obtained GNCs was well controlled to <260 nm under appropriate emulsion process conditions and they showed excellent long-term dispersibility in phosphate buffer saline. MRI measurements clearly indicated the substantial improvement in T 1 effect of the nanoclusters as compared with the individual Gd2O3 nanoplates. The obtained GNCs possessed a high r 1 value of 7.948 s−1mM−1 [Gd], which is 2.23 times higher than that of the commercial product Gd-DOTA, and low r 2/r 1 of 1.04. In vitro test of the obtained GNCs was demonstrated in NIH/3T3 cell lines, and clear T 1-weighted images were obtained. Thus, the PMAO-g-PEG assisted GNCs were potentially useful for T 1-weighted MRI contrast agents.

An investigation was carried out to characterize the tensile behavior of multiwalled carbon nanotube (MWCNT) modified epoxy nanocomposites in the glassy, viscoelastic, and rubbery regimes. 1 and 2 wt% MWCNT predispersed epoxy was used in this study. The cured samples were characterized using dynamic mechanical analysis for selection of different temperatures. The stress–strain behavior and toughness were determined in the temperature band of 25–140 °C. Addition of 1% CNT resulted in 16% improvement in the storage modulus at glassy state but 6% reduction in storage modulus was seen for 2% CNT-epoxy system. Tensile results showed that the strength and modulus have improved for 1% CNT-epoxy system. This study also revealed that for all the three systems, failure strain was maximum near the glass transition temperature (T g) and significantly reduced above T g. Also the CNT-modified epoxies showed improved toughness.

Magnetron-sputtered Ni(W) films appear to possess a high density of nanotwins oriented parallel to the film surface which highly influences the properties of Ni(W) films. A sophisticated analysis method for describing the stacking sequence of close-packed atomic layers by statistical parameters has been developed which is based on the evaluation of intensity streaks in reciprocal space measured by (x-ray) synchrotron diffraction. In particular, the degree of hexagonality introduced by twinning into these ideally face-centered cubic-stacked films can be quantified. The validity of the proposed analysis has been confirmed by direct observation of the stacking sequences of close-packed layers using (high-resolution) transmission electron microscopy. It has been shown that the degree of hexagonality in the as-deposited state is practically proportional to the W content. Further, the thermal stability of the nanotwins increases with increasing W content which can be understood by the appearance of hexagonal close-packed-like domains exhibiting an intrinsic thermodynamic stability.

This study aims at understanding the effects of rotating magnetic field (RMF) on the fading effect of Al–5Ti–1B in commercial pure Al. The results indicate that fading effect is obvious after adding Al–5Ti–1B to Al with a holding time of 20 min. It is fair to claim that the fading effect can be eliminated to a great extent when RMF with magnetic flux densities of 6 and 12 mT is applied until the temperature decreases to 662 °C, which is mainly attributed to the homogeneous distribution of TiB2 particles caused by forced convection. However, refinement performance of pure Al by Al–5Ti–1B can be greatly weakened by RMF with an increase in magnetic flux density to 18 mT, since strong convection aggravates the agglomeration of TiB2 particles. In addition, the inoculated Al treated by a RMF of 6 mT until solidification exhibits a coarser solidification structure compared to that treated until the temperature decreased to 662 °C, which is mainly due to the prolongation of solidification time caused by Joule heat under RMF as proved by thermal analysis.

A combined approach of scanning electron microscopy and digital image correlation was used to examine microstructure-scale strain localization and active deformation mechanisms in ultrafine-grained (UFG) high purity (99.99%) aluminum processed by equal-channel angular pressing (ECAP). The results from tensile tests demonstrate a strong relationship between the heterogeneous microstructure and strain localization. The localized deformation was investigated in areas that contain significantly different microstructural features typical of ECAP processed aluminum. It was found that areas of the UFG microstructure containing primarily low angle grain boundaries deformed by dislocation slip and behaved similarly to a coarse-grained material. The greatest strain localization occurred at high angle grain boundaries (HAGBs) separating distinct microstructure regions and with median surface trace angles of approximately 26.6°. In areas of banded microstructure, shear strain localization as high as 30% and shear displacements of up to 500 nm occurred at the HAGBs separating bands, suggesting grain boundary sliding.

The fracture property estimation of ductile materials with small volumes at room temperature was performed experimentally and analytically in this study. A modified energy method of the small punch test (SPT) was applied to estimate fracture toughness based on the membrane stretch analysis. The effective strain was assumed to be the average value of center strain and contact boundary strain. To overcome the problem involved in strain calculation by microscopic observation, one relatively simple correlation which related effective fracture strain to displacement was proposed. The results obtained by the modified energy model and conventional experiment were in good agreement. Furthermore, a three-dimensional finite element model was established successfully. The influence of ball diameter and center hole diameter in the lower die on the SPT was analyzed by detailed discussion. Finally, the applicability and accuracy of the modified energy model based on the SPT were proved. An economic, effective energy method can be obtained from the present study to assess the properties of in-service components and micrometer scale materials.