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In this work, tungsten–copper (W–Cu) alloy with multi-scale tungsten phase was prepared by cold isostatic pressing, vacuum sintering and hot extrusion processes. The microstructure of W-70Cu alloy was examined by scanning electron microscopy and transmission electron microscopy. The arc erosion resistance of W-70Cu alloy was studied in the JF04C electrical contact testing system. The erosion morphology of the contact surface was characterized. The action mechanism of tungsten particles in arc erosion process was discussed in detail. The arc erosion property and mechanism of W-70Cu alloy were analyzed. The results show that the material transfer occurs from the cathode to the anode. With enhancing the current and voltage, the arcing time and arcing energy increase while the contact resistance falls slightly. In the arc erosion process, tungsten particles increase the work function of W–Cu alloy and make the arc disperse better. The large tungsten particles in W–Cu contact can help to maintain the shape of the contact and delay the occurrence of fusion welding. Tungsten nano-particles enhance the viscosity of the molten pool, reduce metal splashing, and hinder the crack initiation and propagation. Under the action of multi-scale tungsten particles, W–Cu alloy has the better resistance to arc erosion. [ABSTRACT FROM AUTHOR]

The effect of Ru on microstructures, coating texture changes, mechanical properties improvement, and cutting performance enhancement in CVD TiN-TiCN-Al2O3 coated cemented carbide was investigated in this paper. The results show that with the increasing amount of Ru, the mean grain size of the matrix decreases from 1.28 to 0.95 μm. The microstructural refinement of the matrix creates more nucleation sites for coating growth, which further reduces the grain size of the coating. Moreover, the Ru, diffusing from the matrix into the coating, changes the growth direction of partial grains. The coated cemented carbide with 1.5wt% Ru shows the largest hardness of 17.8GPa, which results from the combined influence of the reduction in coating grain size and the decrease in the concentration of TiCN coating {111} texture. In the process of turning 17-4PH stainless steel, due to the improved hardness and plastic deformation resistance of the composite coating, as well as enhanced (104) texture of Al2O3 coating, the flank wear of the coated tool with 0.5wt% Ru is 31.25% lower than that without Ru, which exhibits the best cutting performance. [ABSTRACT FROM AUTHOR]

The non-enzymatic electrochemical sensor has the advantages of fast response and high sensitivity. In this study, the NiMoO4·xH2O nanowires were quickly grown in situ on the carbon cloth substrate (NiMoO4·xH2O NW/CC) in one step by using the dielectric barrier discharge (DBD) micro-plasma method. With the benefits of the open network of 3D binary metal oxide NiMoO4 nanowire self-supporting electrode, large specific surface area, many active sites and the synergistic effect of Ni and Mo, NiMoO4·xH2O NW/CC show excellent electrocatalytic sensing performance for glucose with a high sensitivity of 4510 μA mM−1 cm−2, and a low detection limit of 63 nM (S/N = 3). There is also good selectivity, stability and practical application prospects. It has been shown that the modified DBD micro-plasma method has the advantages of being low in cost, simple and fast, green and environmentally friendly, and therefore it has good application prospects in the preparation of electrochemical sensing materials. [ABSTRACT FROM AUTHOR]

Mg10Ni-MoS2 composites were synthesized, and the amount of molybdenum disulfide (MoS2) and ball milling time was optimized to obtain rapid initial kinetics with high conversion yield at room temperature in simulated seawater. The microstructures and H2 generation thermodynamics were comprehensively investigated to demonstrate the main influential factors on excellent initial hydrolysis performance. Mg10Ni-5 wt%MoS2-15 min can generate 493.3 mL·g-1 H2 at 298 K with 58% yield in 20 s. The H2 generation capabilities of Mg10Ni-5 wt% MoS2-15 min are 569 mL·g-1 H2 and 67%, which are higher than those of Mg10Ni (495 mL·g-1 H2, 56%) in 2 min. The lowest hydrolysis activation energy (18.74 kJ·mol-1) can be achieved by Mg10Ni-5 wt%MoS2, which means low energy consumption. Mg10Ni with higher specific surface area (4.04 m2⋅g-1) than that of Mg10Ni-5wt.%MoS2-15 min (0.78 m2⋅g-1) presents worse H2 generation performance, indicating that higher specific surface area is the secondary determinant for superior initial hydrolysis kinetics and higher conversion yield compared with the added MoS2. The added MoS2 with specific morphologic structure can provide auxiliary mass transfer paths, which shorten the transfer distance and destroy the continuous colloidal layer. Mg-rich alloys optimized for rapid and efficient H2 production performance are expected to be applied large-scale H2 generators. [ABSTRACT FROM AUTHOR]

The as-cast magnesium–nickel–cerium (Mg–Ni–Ce) alloys with nominal component (Mg–10 wt% Ni)1−xCex (x = 0, 5, 10, 15 wt%) are optimized by high-energy ball milling (HEBM). Expandable graphite (EG) and molybdenum disulfide (MoS2) have been introduced as surface catalysis to form (Mg10Ni)95Ce5–5 wt% EG–5 wt% MoS2 composite. The synergetic effects of HEBM and catalysts on H2 production of (Mg10Ni)95Ce5 are comprehensively studied. The thermodynamics are studied by H2 generation curves fitting. The HEBM 0Ce, 5Ce, 10Ce and 15Ce alloys at 291 K can generate 530, 747, 720 and 487 mL g−1 H2 with conversion yields of 59%, 87%, 89% and 64% in initial 15 min, respectively. The addition of surface catalysts EG–MoS2 can further enhance the initial hydrogen generation rate and the final conversion yield within short period at room temperature. 773 mL g−1 H2 corresponding to 95% conversion yield can be obtained by HEBM (Mg10Ni)95Ce5–EG–MoS2 within 1 min at 291 K. The synergetic effects of HEBM and EG–MoS2 can promote rapid initial generation rate and high conversion yield of hydrolysis hydrogen generation of (Mg10Ni)95Ce5–EG–MoS2 composite. This work indicates a promising way to synthesize Mg-based alloys with rapid initial hydrolysis H2 generation kinetics and high conversion yield within a short period. [ABSTRACT FROM AUTHOR]

A novel biomass carbon doped with dual-metal oxide mischcrystal (cobalt oxide and molybdenum oxide) was synthesized by using Enteromorpha (EP) of marine algae as carbon source. Multi-wrinkles biomass carbon (MWBC) with magnetic properties was obtained and formed highly dispersed CoOx/MoOy nanoparticles onto the surface of MWBC in situ via a simple impregnation and direct carbonization at 700 °C. The framework of CoOx/MoOy@MWBC was characterized by scanning electron microscopy, transmission electron microscope, X-ray diffraction and X-ray photoelectron spectroscopy. The as-prepared CoOx/MoOy@MWBC was applied as efficient adsorbents for selective removal methyl blue (MB) at pH 10 from water medium. For comparison, single metal-derived porous carbon, i.e., CoOx@MWBC and MoOy@MWBC, was also synthesized, characterized and tested for MB adsorption. The results exhibited that CoOx/MoOy@MWBC has the highest MB adsorption capacity (1587.3 mg g−1) and excellent selectivity. In addition, it could be easily separated from water by an external magnetic field without any organic reagent added. Adsorption equilibrium data were described by Langmuir and Freundlich isotherms, and kinetic data were described by pseudo-first-order, pseudo-second-order and intraparticle diffusion model. Moreover, CoOx/MoOy@MWBC also owned outstanding stability and renewability, which can be regenerated by an easy-going method of ethanol washing and reused at least 10 times without a significant loss in removal percentage. [ABSTRACT FROM AUTHOR]

This paper presents a study of microscale plastic deformation at the crack tip and the effect of microstructure feature on the local deformation of aluminum specimen during fracture test. Three-point bending test of aluminum specimen was conducted inside a scanning electron microscopy (SEM) imaging system. The crack tip deformation was measured in situ utilizing SEM imaging capabilities and the digital image correlation (DIC) full-field deformation measurement technique. The microstructure feature at the crack tip was examined to understand its effect on the local deformation fields. Microscale pattern that was suitable for the DIC technique was generated on the specimen surface using sputter coating through a copper mesh before the fracture test. A series of SEM images of the specimen surface were acquired using in situ backscattered electronic imaging (BEI) mode during the test. The DIC technique was then applied to these SEM images to calculate the full-field deformation around the crack tip. The grain orientation map at the same location was obtained from electron backscattered diffraction (EBSD), which was superimposed on a DIC strain map to study the relationship between the microstructure feature and the evolution of plastic deformation at the crack tip. This approach enables to track the initiation and evolution of plastic deformation in grains adjacent to the crack tip. Furthermore, bifurcation of the crack due to intragranular and intergranular crack growth was observed. There was also localization of strain along a grain boundary ahead of and parallel to the crack after the maximum load was reached, which was a characteristic of Dugdale-Barenblatt strip-yield zone. Thus, it appears that there is a mixture of effects in the fracture process zone at the crack tip where the weaker aspects of the grain boundary controls the growth of the crack and the more ductile aspects of the grains themselves dissipate the energy and the corresponding strain level available for these processes through plastic work. [ABSTRACT FROM AUTHOR]

Orientation relationships between the growth direction of carbon nanotubes and encapsulated residual iron-containing particles have been determined using transmission electron microscopy. The nanotubes that are prepared by Fe-catalysed chemical vapour deposition on sol–gel Fe(NO3)3-tetraethyl orthosilicate substrates are the helical multiwall type. Nanoscale particles of both the low-temperature α-Fe (ferrite) and high-temperature γ-Fe (austenite) were found in the cavity of the carbon nanotubes with $$ {\left\langle {001} \right\rangle }_{\alpha } $$ , $$ {\left\langle {011} \right\rangle }_{\alpha } $$ and $$ {\left\langle {110} \right\rangle }_{\gamma } $$ parallel to the tube growth direction, respectively. Cementite Fe3C, the most abundant Fe-containing phase in present samples was also found to be entrapped in nanotubes with $$ {\text{[100]}}_{{{\text{Fe}}_{{\text{3}}} {\text{C}}}} $$ or $$ {\text{[101]}}_{{{\text{Fe}}_{{\text{3}}} {\text{C}}}} $$ parallel to the tube axis. The metastable retention of γ-Fe particles at room temperature is ascribed to the strain energy induced at the particle-nanotube interface due to volume expansion upon the γ- → α-Fe phase transformation. The decomposition of initially high aspect-ratio, rod-shape particles into a string of ovulation, while encapsulated in carbon nanotubes is accounted for by the Rayleigh instability. Ovulation leading to reduced particle size has also contributed to increase the surface energy term that counterbalances the total free energy change of phase transformation from γ- to α-Fe and further aids to the metastable retention of γ-Fe. [ABSTRACT FROM AUTHOR]