Three important low valent transition metal oxides were synthesized in supercritical methanol by using inorganic metal salts as precursors. X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and x-ray photoelectron spectroscopy were applied to analyze the composition, structure, and morphology of the products. Results showed that Cu2O, MoO2, and V2O3 were obtained successfully under a supercritical condition of 240 °C and 9.0 MPa. MoO2 and V2O3 displayed sphere-like morphology with average particle sizes of 20–40 and 20–50 nm, respectively. Cu2O particles displayed edge-truncated cubic morphology with a particle size of 2.5 μm. Formation mechanism proposed that high valent metal oxides (CuO, MoO3, and V2O5) were formed firstly in supercritical methanol by the decomposing of precursors and then reduced to target products by free hydroxyl anions. In addition, methanol performed important roles not only as a reaction medium but also as a reducing agent under supercritical fluid conditions.

Bi2Sr2Co2Ox (BSC-222) bulk materials have been prepared in air by single hot pressing or partial melting followed by hot pressing. Thermal transport properties of as-prepared samples were compared with BSC-222 samples prepared by single partial melting. Samples prepared through hot pressing have a high bulk density and improved preferential grain orientation. Bulk density and preferential grain orientation are significantly better in samples processed by partial melting followed by hot pressing. In samples prepared by partial melting, the presence of sub-micrometer-sized secondary phases Bi0.75Sr0.25Ox , Sr-based oxide, and CoO, is observed. The lattice contribution to the total thermal conductivity decreases significantly in partially melted BSC-222 samples. By using a classical phonon transport model, this result demonstrates that the decrease in lattice thermal conductivity in partially melted BSC-222 samples may be linked not only to porosity but also to the presence of defects, induced by partial melting process, which may play an important role in phonon scattering.

The effects of pre-treatments on the precipitate microstructures of an Al–Zn–Mg–Cu alloy are investigated. Meanwhile, the creep-rupture behavior of the under-aged and peak-aged alloys are comparatively analyzed. Additionally, the effects of pre-treatment on the fracture mechanisms are discussed. It is found that the precipitate microstructures are sensitive to pre-treatments. The intragranular precipitates of the peak-aged alloy are larger than those of the under-aged. The precipitate free zone of the peak-aged alloy is wider than that of the under-aged. Some large intergranular precipitates appear on the grain boundaries of the under-aged alloy, and induce the nucleation of microvoids. Eventually, the creep fracture of the under-aged alloy is accelerated. Therefore, the differences in microstructures lead to the shorter creep-rupture life of the under-aged alloy, compared to the peak-aged alloy.

In the paper, 2.5 vol% (TiB + TiC)/Ti composite has been fabricated by in situ casting route. 1-D forging and subsequent multistep rolling in (α + β) phase field are conducted on the as-cast composite and, accordingly, the matrix microstructure is significantly refined, and the distribution uniformity of reinforcements is greatly improved. The tensile properties of the composites with different processing states are tested at room temperature (RT), 600 and 700 °C. The results indicate that thermomechanical processing (TMP) can drastically improve strength and elongation of the as-cast composite both at RT and 600 °C. As tensile temperature increases to 700 °C, the UTSs of the composites gradually reduce while the elongations of the composites are enhanced remarkably after TMP. The degradation in UTS can be related to the matrix softening and interfacial debonding at 700 °C.

Hot deformation and dynamic recrystallization (DRX) behavior of the Cu–Cr–Zr–Ag alloy were studied by hot compressive tests in the 650–950 °C temperature and 0.001–10 s−1 strain rate ranges using Gleeble-1500D thermomechanical simulator. The activation energy of deformation was determined as Q = 343.23 kJ/mol by the regression analysis. The critical conditions, including the critical strain and stress, for the occurrence of DRX were determined based on the alloy strain hardening rate. The critical strain related to the onset of DRX decreases with temperature. The ratios of the critical to peak stress and critical to peak strain were also identified as 0.91 and 0.49, respectively. The evolution of DRX microstructure strongly depends on the deformation conditions in terms of temperature and strain rate. Dislocation generation and multiplication are the main hot deformation mechanisms for the alloy. The addition of Ag can refine the grain and effectively improve the DRX of the Cu–Cr–Zr alloy. It can also inhibit the growth of the DRX grains at 950 °C deformation temperature, making the microstructure much more stable.

The glass-forming Ti75Zr10Si15 and Ti60Zr10Nb15Si15 alloys composed of nontoxic elements may represent new materials for biomedical applications. For this study, melt-spun alloy samples exhibiting glass–matrix nanocomposite structures were subjected to thermal oxidation treatments in synthetic air to improve their surface characteristics. 550 °C was identified as the most appropriate temperature to carry out oxidative surface modifications while preserving the initial metastable microstructure. The modified surfaces were evaluated considering morphological and structural aspects, and it was found that the oxide films formed at 550 °C are amorphous and consist mainly of TiO2; their thicknesses were estimated to be ∼560 nm for Ti75Zr10Si15 and ∼460 nm for Ti60Zr10Nb15Si15. The thermally treated sample surfaces exhibit not only higher roughnesses and higher hardnesses but also improved wettability compared to the as-spun materials. By immersion of oxidized samples in simulated body fluid Ca- and P-containing coatings exhibiting typical morphologies of apatite are formed.

A new red-emitting phosphor, Eu3+ doped Al5BO9, was prepared for the first time by calcining the precursor of K2[Al(B5O10)]·4H2O:Eu3+ which was synthesized by a facile hydrothermal route. The obtained samples were characterized by energy dispersive x-ray spectrometer, x-ray powder diffraction, IR, scanning electron microscopy, photoluminescence, and photoluminescence excitation spectrum (PLE). Moreover, the influences of Eu3+ doping concentration, calcination temperature, and calcination time on the luminescence properties of Al5BO9:Eu3+ phosphor were also investigated. The phosphor with optimal luminescent intensity and the higher red/orange ratio was obtained by sintering the precursor at 1300 °C for 5.5 h, with 5% doping concentration, in which its luminescent decay lifetime and quantum efficiency were also measured. It is also found that the phosphor prepared by conventional solid-state reaction method exhibits the dominant transition at 591 nm (orange) with the lower color purity, while the phosphor prepared by the present precursor method exhibits the dominant transition at 615 nm (red) with the higher color purity, which indicates that this is a good method for preparing Al5BO9:Eu3+ red phosphor.

Thermomigration (TM) and electromigration (EM) are two persistent reliability issues and they generally appear concurrently in solder joints. Many previous studies have attempted to understand the fundamental principles behind these phenomena with the majority of which focusing their interest into the faster migration elements in solders like Bi, Ni, or Cu. However, Sn as the slower migration element has not received that much attention. In the present study, a special linearly symmetrical structure was used. An unusual TM phenomenon of Sn atoms in the Sn58Bi solder joint was observed. The unusual TM of Sn atoms along the vertical edges was attributed to the coupled effect of the EM in the horizontal direction and the TM in vertical direction. The relationships between the microstructural characteristics and the temperature distribution were established. The results also indicated that elevated temperature and sufficient thermal gradient were the two major factors that caused TM.

Using first-principles calculations, the fundamental understanding of the structure, electronic, elastic, lattice dynamic, and optic properties of three Mg-based ternary chalcopyrite semiconductors have been analyzed in detail within density functional theory scheme. To ensure an accurate determination of our calculated results, we considered five popular generalized gradient approximation formulations such as Perdew and Wang, Perdew–Burke and Ernzerhof (PBE), revised PBE, modified PBE, and Armiento–Mattson 2005 as well as local-density approximation (LDA) for the exchange-correlation potentials. It is found that all the calculated values of band gap for these compounds are underestimated compared to existing studies, while LDA-based functional gives better results than others. The electronic band structure demonstrated that these compounds have direct band gap at the Γ point in the Brillouin zone. It is observed that these compounds are mechanically stable in the chalcopyrite structure.

Cross-weld hardness profile, notch-tensile strength, and impact toughness of T92 steel heat-affected zone (T92 HAZ) of dissimilar T92/TP316H welds were studied in dependence of their postweld heat treatment (PWHT) and subsequent long-term aging. Two weldments series were individually subjected to either “single-step” tempering PWHT or a modified “two-step” renormalizing and tempering PWHT. Subsequently, the welds were isothermally aged at 625 °C for durations from 500 up to 11,000 h. The “single-step” PWHT preserved sharp hardness gradient of T92 HAZ, whereas the “two-step” PWHT led to the hardness values equalization. The T92 HAZ of the weldment after the “two-step” PWHT exhibited initially lower strength and higher toughness, compared to the weldment after the “single-step” PWHT. However, after long-term aging a more suitable combination of T92 HAZ mechanical properties i.e., the higher toughness and acceptable strength exhibited the weldments processed by “single-step” PWHT.

Gamma prime (γ′) stability and its influence on tensile behavior of a newly developed wrought superalloy with various Fe contents was studied both experimentally and thermodynamically. The results show that the γ′-solvus temperature is higher and γ–γ′ lattice mismatch is bigger in the alloy with the lower Fe content. During long-term thermal exposure at 650–750 °C, the coarsening behavior of γ′ precipitates follows Ostwald ripening kinetics and the lower Fe content can decrease the coarsening rate of γ′ precipitates due to the increase of the activation energy for γ′ coarsening. Moreover, the lower Fe content can retard the transformation from γ′ to η phase. The tensile properties of the alloys with different Fe contents are almost same after standard heat treatment. However, after thermal exposure, the decrease of tensile strength in the alloy with lower Fe content is less than that of the alloys with higher Fe content due to the improvement of γ′ stability.

The microstructural evolution during spark plasma sintering of ultrafine WC–1 wt% Si (n-WC–Si) is presented. At 1323 K (T < TmSi), extensive stacking faults on the $\left\{ {10\bar 10} \right\}$ prismatic planes are observed. The defect microstructure can be described as a combined shear of $1/6\left\langle {\bar 12\bar 13} \right\rangle$ on the prism planes and simultaneous out-diffusion of carbon through the faults to the interparticle boundaries. At temperatures near TmSi (1673 K), a large fraction of abnormally grown platelets is observed. These platelets contain a single planar defect on their basal planes, described by a ${1 \mathord{\left/ {\vphantom {1 3}} \right. \kern-\nulldelimiterspace} 3}\left\langle {10\bar 10} \right\rangle$ translation of the carbon atoms across a Σ1 grain boundary (GB). Three factors contribute to the abnormally high density of platelets: (i) the low-temperature prismatic dislocations interact to form facet-roughening steps/kinks that act as nucleation sites, (ii) a liquid phase triggers an increased growth rate in the vicinity of the Si inclusions, and (c) the basal twin produces a re-entrant edge for 2D nucleation.

The effect of annealing treatment on the microstructures, mechanical, and wear properties of a CuZnAlMnSiNiCr brass alloy is investigated. The results indicate that nanosized Mn5Si3 particles are observed to precipitate from the β phase at temperatures above 750 °C. After annealing at 800 °C for 4 h, the formation of finely, coherent precipitates dispersed within the matrix results in the great improvement of strength, hardness and thus the high wear resistance, which can be proven by the decreased wear rates and friction coefficients. According to the examination of the wear topography, adhesive, abrasive, and oxidative wear are found to be the major wear forms during the dry sliding wear. After the precipitation-hardening treatment, the adhesion and abrasion decrease, and few spallings and cracks are observed on the worn surfaces. In addition, the wear behavior of the alloy is found to be strongly dependent on its strength and hardness.

Zinc(tris) thiourea sulphate (ZTS) is as one of the potential candidates for nonlinear optical applications due to its high nonlinearity and excellent optical properties. The synthesis of pure and titan yellow dye doped ZTS has been done and good quality rod-like single crystals of size ∼60 mm long and 2 mm diameter were grown through simplest and low cost route. The structural and vibrational analysis rules out any extra phase or change in structure of ZTS due to dye doping. Scanning electron microscope study reveals that the grown crystals are of good quality with rod-like morphology. Diffuse reflectance spectrum show a new absorption band at ∼460 nm, which may be predicted as a signature of dye. The optical band gap was calculated to be 4.6 eV for pure and 4.5 eV for doped ZTS crystals. The violet-blue emission centered at 412 nm in pure and at 414 nm in doped crystals with an additional green emission bands at 528 nm with high intensity in the photoluminescence spectra were observed. The value of ε1 is found to be enhanced from 10 (in pure) to 14 (in doped) crystals. The properties are enhanced due to dye doping and may be more useful than pure crystals in optoelectronic devices.

Layered molybdenum disulfide (MoS2) has attracted great attention owing to its unique properties. However, synthesizing large area thin film with high crystal quality and uniformity remains a challenge. The present study explores large scale MoS2 growth methods, i.e., two-step method of sputtering-chemical vapor deposition and direct sputtering method, and applies them to fabricate field effect transistors and supercapacitors, respectively. The thickness modulated MoS2 films by two-step method exhibited high field effect mobility [∼12.24 cm2/(V s)] and current on/off ratio (∼106). The direct sputtering of MoS2 demonstrated excellent electrochemical performance with a high capacitance (∼30 mF/cm2) and cyclic stability upto 5000 cycles. Our growth methods reported here for the large scale MoS2 with high uniformity can trigger the development of several important technologies in two-dimensional materials.

In this work, the selective removal of ions from multicomponent mixtures using functionalized magnetic nanoparticles (FMNPs) was demonstrated. As, Sb, and Se ions were efficiently removed from complex mixtures, such as Rhodiola rosea extracts and influent water from the sewage treatment unit of a beer brewery. As, Sb, and Se ions could be selectively adsorbed by FMNP, as demonstrated by the inductively coupled plasma mass spectrometer analyses. We also demonstrated that Pb ions are weakly adsorbed, whereas Cu, Cd, and Zn ions cannot be adsorbed by FMNP. The complexity of the mixture did not affect the selective removal of As, Sb, and Se ions. FMNP could be recycled and used repeatedly. Magnetic separation could then be applied for the selective separation of complex mixtures, such as plant extracts, industrial wastewater, and tap water.