An eco-friendly, green aqueous technique for the preparation of NiO–Ag bimetallic and its individual monometallic nanoparticles (NPs) is succinctly described by utilizing nontoxic and abundantly available tannic acid at room temperature. The so-synthesized nanoscale particles were characterized using various techniques including HRTEM, DLS, zeta potential, SAED, SEM, EDAX, XRD, IR, and UV–vis spectroscopy. These monometallic and bimetallic NPs have a narrow size distribution with spherical morphology. Moreover, the average diameters of all these three different NPs are almost identical and ranges from 7 nm to 10 nm as measured from HRTEM. DLS readings further confirm that the so synthesized particles are in nano range. A comparative catalytic efficacy of the ensuing nanoparticulate materials were assayed employing photodegradation and chemical reduction of methyl violet (MV) at room temperature. NiO–Ag NPs exhibits higher catalytic potential and it took only 15 min to completely reduce MV in presence of NaBH4. The rate constants for both the chemical reduction and photodegradation reactions follow the order: k NiO–Ag bimetallic NPs > k NiO NPs > k Ag NPs > k uncat. Higher catalytic performance of the bimetallic system is reckoned on composition effect which basically results due to synergistic electronic effect.

Various routes (unidirectional, cross, and three directions) normal and different speed rolling (DSR) are conducted on pure titanium sheet at 673 K and sequent 933 K annealing is followed. The results show that transverse direction (TD)-split double peak texture is kept during unidirectional rolling and a fiber basal texture is formed after cross and three-direction rolling. However, TD-split texture is preserved and rotates about 45° while the fiber basal texture is generated after cross and three direction rolling combining (DSTDR) DSR, respectively. This may be related to the changed strain path and induced shear deformation as well as thermal activation. Due to rotation of grains, the anisotropy of mechanical properties of Ti sheets decreases, especially in various DSR routes. Erichsen value is improved greatly in DSTDR specimens.

SrZrO3 ceramic with perovskite-type structure was synthesized by a conventional solid-state reaction method at 1500 °C for 3 h. The crystal structures were studied by x-ray diffraction (XRD), and lattice vibrational modes were obtained by Raman and Fourier transform far-infrared (FTIR) reflection spectroscopy. The dielectric properties of the samples were also measured. According to XRD data, the SrZrO3 ceramic displayed the orthorhombic structure Pbnm (62). The Raman spectrum with ten active vibrators can be fitted by the Lorentzian function, and the vibrators were assigned. Far-infrared spectrum with six infrared active modes was fitted by the four-parameter semiquantum models. Consequently, the modes were assigned as F1u (1) (102 cm−1), F2u (2) (120 cm−1), F1u (3) (140 cm−1), F3u (4)′ (228 cm−1), F3u (4)″ (287 cm−1), F1u (5) (326 cm−1), and F1u (6) (527 cm−1). The infrared mode F1u (1), that can be represented as the Sr–ZrO6 inverted translational vibration, has the highest contribution to the dielectric properties (permittivity and dielectric loss). The calculated data agree well with the measured values.

The lithium ion battery is the most promising battery candidate to power battery electric vehicles. For these vehicles to be competitive with those powered by conventional internal combustion engines, significant improvements in battery performance are needed, especially in the energy density and power delivery capabilities. Promising substitutes for graphite as the anode material include silicon, tin, germanium, and various metal oxides that have much higher theoretical storage capacities and operated at slightly higher and safer potentials. In this critical review, metal oxides-based materials for lithium ion battery anodes are reviewed in detail together with the progress which is made in my lab on that topic. Their advantages, disadvantages, and performance in lithium ion batteries are discussed through extensive analysis of the literature, and new trends in materials development are also reviewed. Two important future research directions are proposed and performed in my lab, based on results published in the literature: the development of composite and nanostructured metal oxides to overcome the major challenge posed by the high capacity of metal oxide anodes.

Dilute magnetic semiconductors are attractive due to their potential in spintronic devices. In this work, vanadium doped ZnO system has been studied to see its future as a dilute magnetic semiconductor. Vanadium doped ZnO thin films where vanadium percentage is 2, 3, and 5% are deposited by pulsed laser technique (PLD). The lattice parameter c derived from the (002) diffraction peak increases as vanadium content increases, suggesting vanadium substitution for Zn in ZnO lattice. Photoluminescence (PL) measurements at low temperature shows the emission peak at 3.30 eV which hint toward p-type doping in ZnO. X-ray photoelectron spectroscopy (XPS) results show that vanadium exists in V2+ and V4+ valence state, which is in agreement with the XRD and PL results and support the vanadium doped ZnO phase. The ferromagnetic behavior also supports the formation of vanadium doped ZnO phase in thin film samples.

The polycrystalline Nd3+-doped rare earth orthotantalate LuTaO4 was synthesized with high temperature solid-state reaction method, and the structure was determined by applying the Rietveld refinement to its x-ray diffraction. Also, the emission and excitation spectra at 7.6 K have been analyzed. The free-ions and crystal-field parameters were fitted to the experimental energy levels with the root mean square deviation of 14.6 cm−1. According to the crystal-field calculations, 152 Stark energy levels of Nd3+ were assigned. Finally, the fitting results of free-ions and crystal-field parameters were compared with those already reported for Nd3+:YAlO3. The results indicate that the free-ions parameters are similar to those of the Nd3+ in LuTaO4 and YAlO3 hosts except for the values of two-body electrostatic parameter γ, and the 2-rank crystal-field parameters of two hosts have relatively large differences while other crystal-field parameters have been similar to each other. Moreover, the crystal-field interaction of Nd3+ in LuTaO4 is stronger than that in YAlO3.

In the present paper, 10 vol%TiC/Ti–6Al–3Sn–3.5Zr–0.4Mo–0.75Nb–0.35Si composite produced via in situ casting technique was tested in the temperature range from room temperature to 900 °C and much attention was paid on the microstructural evolution during high-temperature tensile test. It was found that the variation of microstructures in deformation zones with strain exhibited different trends at different temperatures. Below 600 °C, dislocation density increased with strain over the entire strain range. As temperature increased to 700 °C, dislocations proliferated rapidly in the initial deformation and then dislocation annihilated through dynamic recovery. Above 800 °C, the variation of microstructures in deformation zones with strain was similar to that at 700 °C at the beginning but at higher strain, dynamic recrystallization (DRX) occurred, leading to the formation of equiaxed microstructure. Microstructural evolution in deformation zones corresponded to the variation of tensile stress–strain characteristics with temperature, reflecting the hardening or softening feature of matrix. Dynamic recovery ascribed to the flow softening of the composite at 700 °C, while flow softening is owing to dynamic recovery and DRX above 800 °C. In addition, matrix softening should show different trends in different temperature ranges.

Three-dimensional (3D) printing of metallic materials involves the layerwise consolidation of feedstock materials in the form of powder, wire, or sheet using various energy sources to form complex shapes. The past two decades have witnessed significant advances in the field, in terms of both technologies and materials for metal 3D printing. This has led to widespread exploration and adoption of the technologies across industry, academia, and R&D organizations. This article presents an overview of the field of metal 3D printing. A brief history of metal 3D printing is followed by an overview of metal 3D printing methods and metallic material systems used in these methods. Microstructure and properties, and their relationship to process parameters are discussed next, followed by current challenges and qualification issues. The article concludes with future trends and a brief description of the invited articles included in this special issue.

The capabilities of metal additive manufacturing (AM) are evolving rapidly thanks to both increasing industry demand and improved scientific understanding of the process. This article provides an overview of AM of the Ti-6Al-4V alloy, which has essentially been used as a yardstick to gauge the capability of each metal AM process developed to date. It begins by summarizing the metal AM processes existing today. This is followed by a discussion of the macro- and microstructural characteristics, defects, and tensile and fatigue properties of AM Ti-6Al-4V by selective laser melting, laser metal deposition (both powder and wire), and selective electron-beam melting compared to non-AM Ti-6Al-4V. The tensile and fatigue properties of as-built AM Ti-6Al-4V (with machined or polished surfaces) can be made comparable, or even superior, to those of Ti-6Al-4V in the most commonly used mill-annealed condition. However, these properties can exhibit a large degree of scatter and are often anisotropic, affected by AM build orientations. Post-AM surface treatments or both the post-AM surface and heat treatments are necessary to ensure the minimum required properties and performance consistency. Future directions to further unlock the potential of AM of Ti-6Al-4V for superior and consistent mechanical properties are also discussed.