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Effects of creep aging on strength and toughness and microstructure evolution of Al-Cu-Li alloy were investigated by tensile test and Kahn tear test at room temperature, combined with fractograph and transmission microstructure analysis. The specimens of pre-strain creep aging state (CA) have been studied and compared with artificial aging state (AA) and pre-strain artificial aging state (PA). It is demonstrated that pre-strain before artificial aging process can improve the strength property and the fracture toughness of Al-Cu-Li alloy. On top of that, both of them can be further improved by creep aging process: the yield strength was increased by 8.7% and the unit initiation energy of Kahn tear was increased by 11.7%. The increasing of fracture toughness has also been verified by Kahn tear fractographs that the dominating fracture type changes from the ductile intergranular fracture to the ductile transgranular fracture. Transmission electron microscopy revealed that creep aging promotes the nucleation of T 1 phase, resulting in a fine and dense distribution of precipitates in the matrix, and the enrichment of subgrain boundary T 1 precipitates was greatly reduced. [ABSTRACT FROM AUTHOR]

The purpose of this work was to investigate the feasibility of using sputtered Ti/W-Ti/Ti multilayer as diffusion barrier and buffer layers between β -Zn 4 Sb 3 thermoelectric (TE) material and Ag interconnect layer for mid-temperature TE module applications. Interdiffusion at the interface was examined by both scanning electron microscope and Auger electron spectroscopy. After penetrating the Ti buffer layer, Ag, Zn and Sb were successfully blocked by the W-Ti diffusion barrier layer. We also proved that the TE sample with diffusion barrier and buffer layers showed phase stability after high temperature aging. Also, the sheet resistance decreased as the temperature increased and it indicated good electrical properties at high working temperatures. In addition, the solid-liquid interdiffusion method was used to join the TE module, and the bonding remained stable at the TE module working temperature. [ABSTRACT FROM AUTHOR]

Solute segregation at phase boundary (PB) is critical for stabilizing nano-precipitates, which plays a decisive role in designing Mg alloys with high thermal stability. To clarify the fundamental factors that govern the PB stability, impacts of solute Ag, Sn, Bi, and In on interfacial properties of coherent α-Mg (0001)/Al 2 Ca (111) were systematically investigated via first-principles calculations. Solute segregation was proven to affect the PB stability by both chemical and mechanical contributions. Feasible alloying elements that could stabilize the nano-precipitates should form strong bonding and/or alleviate the distortion near PB by segregation, wherein the former plays a more dominant role. Accordingly, Ag segregation at PB was deemed to improve the thermal stability of the Al 2 Ca phase. Our work aims to provide a new perspective for the development of Mg alloys for potential high-temperature applications via tailoring interfacial properties. [Display omitted] • Detailed atomic structure of Mg/Al 2 Ca phase boundary (PB) was determined by calculating the separation work. • Ag was proposed as candidate alloying element to stabilize Mg/Al 2 Ca PB. • Chemical and mechanical contribution act synergistically in determining the change in PB energy after solute segregation. • Element for stabilizing the Al 2 Ca precipitates should form strong bonds and alleviate the strain of PB after segregation. [ABSTRACT FROM AUTHOR]

(La 0.4 Ce 0.6 O 2- δ ) 1 -x (FeO 1.5 ) x ( x  = 0, 0.03, 0.04, 0.10, and 0.20) was synthesized by co-precipitation method. Crystalline structure, microstructure, electronic and ionic conductivities were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Hebb-Wagner method, and AC impedance method, respectively. The effects of FeO 1.5 dopant on the properties of samples were investigated. A limiting current oxygen sensor based on (La 0.4 Ce 0.6 O 2-δ ) 0.96 (FeO 1.5 ) 0.04 as dense diffusion barrier and 8YSZ as solid electrolyte was prepared by Pt paste bonding method. The effects of temperature and oxygen concentration on sensing performance were investigated. The XRD measurements showed that the solid solubility of FeO 1.5 in La 0.4 Ce 0.6 O 2- δ (LDC) was between 3 mol% and 4 mol%. The electrical conductivity analysis showed that (La 0.4 Ce 0.6 O 2- δ ) 0.96 (FeO 1.5 ) 0.04 had the highest electronic and ionic conductivities. The sensor had a good performance and the limiting current depended linearly on the oxygen concentration, and exponentially on 1/ T . [ABSTRACT FROM AUTHOR]

TiNi-based shape memory alloys (SMAs) have been largely utilized in stents, orthopedic endo-prostheses and orthodontic implants. While bacterial infection in medical implants is the most common complication, development of antibacterial TiNi-based SMAs is essential. In the present study, a novel antibacterial TiNiCuAg shape memory alloy film (SMAF) was successfully developed by adding silver into TiNiCu matrix. The structural and biological properties of TiNiCuAg SMAF, including crystal structures, phase transformation temperatures, shape memory effect, antibacterial ability and cell cytotoxicity, were systematically investigated. The results showed that the phase transformation temperature gradually decreased and silver started to precipitate with the increasing silver content. The single-stage B2 ↔ B19′ transformation occurred in TiNiCu and Ti 51 Ni 43.5 Cu 4.5 Ag 1 films, while the two-stage B2 ↔ R ↔ B19′ transformation occurred in Ti 49.6 Ni 42 Cu 6.9 Ag 1.5 , Ti 47.4 Ni 41.2 Cu 6.4 Ag 5.6 and Ti 47.7 Ni 41.2 Cu 4.1 Ag 7 films. Moreover, compared to TiNiCu films, TiNiCuAg films performed the better shape memory effect with the increasing silver content. For antibacterial tests, the TiNiCuAg films with the Ag content of 5.6 at.% had the best antibacterial ability against S. aureus and E. coli compared to those of TiNi and TiNiCu films. For cytotoxicity assay, all films maintained good biocompatibility and revealed no cell toxicity for L929 cells. As a result, excellent antibacterial ability and good biocompatibility suggested that TiNiCuAg SMAFs had potential applications for medical implant to avoid bacterial infection. [ABSTRACT FROM AUTHOR]

Although their preparation remains challenging, N-doped SiC nanostructures have received much attention due to their high performance characteristics compared to pure Si 3 N 4 and SiC phases. In this study, N-doped SiC nano-powders were synthesized in one step through hexamethyldisilane pyrolysis in Ar/N 2 plasma atmosphere. The results show that the undoped products included β-SiC nanoparticles sized in the range of 5–20 nm and carbon layers with 1–10 layers, while N-doped SiC nano-powders were mainly amorphous Si 3 N 4 /SiCN aggregates sized in the range of 30–200 nm with some β-SiC nanoparticles attached. The increased N 2 flow rate and arc currents favored nitrogen doping and carbon removal. In addition, according to the X-ray photoelectron spectroscopy, the highest N-doping level approached 20% (atomic ratio). Nitrogen doping can effectively adjust the dielectric properties and affect the microwave absorption ability. The optimal reflection loss reached −56.2 dB at 8.9 GHz under an absorber thickness of 3.1 mm when the N-doping level was 12.1%. Moreover, due to the defect states, the N-doped SiC nano-powders exhibited good photoluminescence performance in the blue-green emission region. Therefore, the synthesized N-doped SiC nano-powders developed herein present potential applicability as microwave absorbers and light-emitting sources. • N-doped SiC with high doping amount (∼19.3%) were prepared by atmospheric plasmas. • N-doped SiC was amorphous Si3N4/SiCN aggregates attached by β-SiC nanoparticles. • N-doped SiC exhibited strong microwave absorption with the optimal RL of − 56.2 dB. • The nitrogen doping contributed to blue-green PL emission due to the defect states. [ABSTRACT FROM AUTHOR]

Na 5 Lu 9 F 32 single crystals co-doped with various Er 3+ /Yb 3+ concentrations were grown by an improved Bridgman method for the first time. The crystal structure is characterized by means of X-ray diffraction (XRD). High transmission in the range from 400 nm to 7150 nm and maximum phonon energy about 441 cm −1 for the Na 5 Lu 9 F 32 single crystals are obtained from the measured transmission and Raman spectra, respectively. The Judd-Ofelt parameters of Er 3+ in the obtained crystal was calculated and discussed according to the measured absorption spectra. Compared with the Er 3+ single-doped Na 5 Lu 9 F 32 crystal, an obviously enhanced emission band at 1500 nm was observed upon excitation of 980 nm laser diode (LD) via energy transfer from Yb 3+ to Er 3+ . Decay curve fitting using a Inokuti-Hirayama expression indicates dipole-dipole energy transfer from Yb 3+ to Er 3+ .The maximum emission cross section at ∼1.5 μm was also calculated to be 10.12 × 10 −20 cm 2 for the Na 5 Lu 9 F 32 single crystal of 1% Er 3+ and 6% Yb 3+ in molar fraction doping concentration. [ABSTRACT FROM AUTHOR]

• Pure phase CsCu 2 I 3 films were prepared using the pure physical pulsed laser deposition technology. • The heterojunction detector is self-powered with on/off ratio of 2150 at 0V. • The heterojunction detector has very good spectral selectivity and sensitive to UV light in the range of 280nm~370nm. • The peak responsivity (0V, 330nm) and the peak detectivity of the detector are 7.1mA/W and 2.6×1011 Jones, respectively. • The photodetector exhibits excellent reproducibility and stability. All-inorganic perovskite CsCu 2 I 3 thin films have been prepared on Si(100) substrates by pulsed laser deposition technology. And the influence of the substrate temperatures on the morphology, structure and optical properties of the CsCu 2 I 3 films was investigated by SEM, XRD, PL and absorption spectra. A prototype CsCu 2 I 3 /Si n-n heterojunction UV photodetection device was constructed with LiF/Al and Au Ohmic contact electrodes. The photodetector demonstrates excellent self-powered photoresponse performance with an on/off ratio of ~2150 at 0 V. The device also exhibits good spectral selectivity and photoresponse characteristics in the UV range (280–370 nm). The peak responsivity (R) and specific detectivity (D *) of the CsCu 2 I 3 /Si heterojunction device are 7.1 mA/W and 2.6 × 1011 Jones at 0 V and 330 nm (~700 μW/cm2) light illumination, and shows good stability and reproducibility. [ABSTRACT FROM AUTHOR]

To enhance the rate and cyclic performances of LiMnPO 4 cathode material for lithium-ion batteries, Mn is partially substituted with Fe, and LiMn 1− x Fe x PO 4 ( x = 0.2, 0.3, 0.4, 0.5) solid solutions are synthesized and investigated. Amphiphilic carbonaceous material (ACM) forms well carbon coating and connects the LiMn 1− x Fe x PO 4 crystallites by a three-dimensional (3D) carbon network. The synergetic Fe substitution and carbon connection obviously improve the samples’ rate capacities and cyclic stability. The optimized LiMn 0.6 Fe 0.4 PO 4 /C sample delivers discharge capacities of 160 mA h g −1 at 0.05 C, 148 mA h g −1 at 1 C, and 115 mA h g −1 at 20 C. All samples have well capacity retention (>92%) after 50 charge/discharge cycles at 1 C. The enhanced electrochemical properties are mainly attributed to the improvement of Li ion and electron transport in the LiMn 1− x Fe x PO 4 /C samples, respectively mainly resulting from their modified crystal structures caused by Fe substitution and the 3D carbon coating/connection originating from ACM carbonization. LiMn 1− x Fe x PO 4 materials exhibit two discharge plateaus at ∼4.0 and ∼3.5 V (vs. Li + /Li), whose heights respectively reflect the redox potentials of Mn 3+ /Mn 2+ and Fe 3+ /Fe 2+ couples. The plateaus’ lengths correspond to the Mn/Fe ratio in LiMn 1− x Fe x PO 4 and are affected by the kinetic behavior of samples. Though the ∼4.0 V plateau shrinks with increasing discharge rate, the ∼3.5 V plateau may slightly elongate. Moreover, the Fe substituted in the partial Mn sites could significantly improve the Li ion diffusion, thus enhance the kinetic behaviors of LiMn 1− x Fe x PO 4 . [ABSTRACT FROM AUTHOR]

• C-coated β-SiC nanoparticles with size of about 8 nm were prepared by plasmas. • SiO 2 -coated SiC nanoparticles were synthesized by heat treatment in the air. • SiO 2 layers enhanced the blue-green PL emission due to the surface/defect states. • C-coated SiC exhibited strong microwave absorption with optimal RL of −38.4 dB. Plasma-generated SiC nanoparticles are easily functionalized due to their ability to be easily oxidized. In this study, SiC nanoparticles were synthesized in non-thermal arc plasmas via hexamethyldisilane decomposition, and the products were modified by heat treatment under air atmosphere. Results indicated that the plasma-generated SiC nanoparticles were C-coated SiC nanoparticles with an average size of 8 nm, while the heat treatment transformed the initial carbon coating layers into SiO 2 layers to form SiO 2 -coated SiC nanoparticles by surface oxidation. The formation of SiO 2 layers enhanced the photoluminescence performance in the blue-green emission region, and also resulted in a blue-shift in the photoluminescence peak mainly due to the surface/defect states. The C-coated SiC nanoparticles exhibited excellent microwave absorption ability, and the optimal reflection loss approached −38.4 dB at 11.7 GHz under an absorber thickness of 2.0 mm; however the formation of SiO 2 layers after modification decreased the conduction loss of SiC nanoparticles, thus weakening their microwave absorption. These results afford a new strategy for designing and synthesizing C/SiO 2 -coated SiC nanoparticles. [ABSTRACT FROM AUTHOR]

Highlights: [•] The single phase of tetragonal ZrO2 formed when calcined at 1223K for 1h. [•] The tetragonal ZrO2 fully converted to ZrSiO4 when calcined at 1323–1473K for 1h. [•] The activation energy of t-ZrO2 formed is 399.9kJ/mol when 5mol% Fe2O3 added. [•] The activation energy of the Fe/ZrSiO4 formed is 257.7kJ/mol when 5mol% Fe2O3 added. [•] The growth morphology parameter and crystallization index are about 2.0 and 1.0. [Copyright &y& Elsevier]

Highlights: [•] As Al or Zn contents increase, GSF energies of Mg-Al-Zn solid solution decrease. [•] As Al or Zn contents increase, more locations with low GSF energy emerge. [•] Al and Zn dopings decrease GSF energy by softening Mg–Mg of slip planes. [•] Reduced GSF energy promotes activation of non-basal slip and enhances plasticity. [•] Criterion for predicting the most probable location for planar defect is proposed. [Copyright &y& Elsevier]

• Plasma Oscillatory Pressure Sintering technology was firstly used to prepare Mo-Si-B alloy, which showed better performance. • The alloy with 9 Hz oscillatory frequency had 97.78% relative density and 11.43 MPa √ m fracture toughness, and its microstructure was refined. • Oscillatory sintering had obvious effect on the closure of micro pores, which was worthy of further research and development of porosity-free structure of Mo-Si-B alloy. [Display omitted] Molybdenum silicon boron alloy is regarded as a new generation of ultra-high temperature alloys and is expected to replace the existing nickel-based alloys. However, the molybdenum silicon boron alloys prepared by powder metallurgy exhibited low density and had many pore defects, which were left hanging in the air. Here, a novel oscillatory sintering method is used to replace the traditional atmospheric sintering. It is found that the addition of the oscillatory frequency improved the density and mechanical properties of the alloy, and made the crystal grains refined to a large extent. It did have certain reference value for the preparation and development of molybdenum silicon boron alloy. [ABSTRACT FROM AUTHOR]

The composition and morphology of the Fe-bearing phase play a significant role in the mechanical properties of aluminum (Al) alloy sheets. In this work, we have studied the formation of Fe-bearing phases in an Al-0.53Mg-0.69Si-0.14Fe (wt%) alloy under the twin-roll casting (TRC) and the direct chill casting (DC) processes, respectively. We found that the π-AlFeMgSi phase was formed in the as-cast TRC sample, while the β-AlFeSi phase was formed in the as-cast DC sample. The differences in the formation of Fe-bearing phases are attributed to the promotion of the peritectic reaction to form the π-AlFeMgSi phase via the TRC process. Furthermore, after homogenization treatment at 550 °C and 2 h, the π-AlFeMgSi phase in the as-cast TRC sample completely decomposed into the fine β-AlFeSi phase, while it was insufficient to dissolve the β-AlFeSi phase in the as-cast DC sample. This is owing to the lower dissolution temperature of the π-AlFeMgSi phase compared to the β-AlFeSi phase. The decomposition of the π-AlFeMgSi phase expands the solid solubility and promotes the aging precipitation, resulting in higher yield strength of the TRC sample than that of the DC sample during the peak-aging treatment. Our work provides new insight into the development of high-performance AA6xxx series alloys based on the TRC process. ● The π-AlFeMgSi phase was found in the as-cast twin-roll casting (TRC) sample. ● The homogenization treatment of 550 °C -2 h can make the π-AlFeMgSi phase dissolved. ● The mechanism of TRC phase formation was revealed. ● Microstructure and tensile properties of TRC AA6005 aluminum sheet were studied. [ABSTRACT FROM AUTHOR]

Abstract: The present study established a time-saving technique for hydrogen uptake measurements using a high-pressure thermo-gravimetric analyzer (HPTGA). The critical buoyancy effects were considered in the analysis model. The HPTGA technique developed here for metal–organic frameworks (MOFs) was validated through independent experiments. The room temperature (RT) hydrogen uptake of MOFs via spillover was significantly enhanced by use of a bridge-building treatment. MOF samples with different structural parameters and RT hydrogen uptake performance can be prepared and manipulated through various factors affecting their synthesis. The structural evolution of MOFs within various steps during the synthesis and bridge-building processes were investigated by electron microscopy, nitrogen sorption isotherm analysis, and powder X-ray diffraction. [Copyright &y& Elsevier]

Vanadium oxide (B) (VO 2 (B)), easily obtained by a hydrothermal method, can be transformed to VO 2 (M/R) under high-temperature annealing treatment (> 500 °C) without oxygen atmosphere. However, the coarsening of VO 2 (M/R) particles is always observed after high-temperature annealing, which may seriously degrade optical properties. In this study, the ball milling method is used, for the first time, to transform VO 2 (B) nanobelts into spherical VO 2 (M/R) nanoparticles with the average particle size of 38 nm at room temperature and under atmospheric conditions. The effects of ball-to-powder weight ratio (BPR) and milling time on crystalline phase and morphology of VO 2 were systematically investigated and found the optimum processing parameters with BPR of 10:1 and the milling time of 3 h. The thin coating based on the obtained VO 2 (M/R) nanoparticles shows good optical properties that the modulation ability can reach up to 14.03% while the visible light transmittance is 41%, which promotes the practical application in smart windows. In addition, the mechanism of the phase transformation from VO 2 (B) to VO 2 (M/R) is analyzed and confirms that the pressure caused by ball collision plays a major role in the ball milling process. [Display omitted] • VO 2 (B) was transformed into VO 2 (M) by high-energy ball milling at room temperature and atmospheric conditions. • The optical properties of the milled samples are obviously better than those of the annealed samples. • The high-energy ball milling method is a new idea for the preparation of VO 2 (M). • The pressure produced by ball impact is the driving force of phase transformation. • The high-energy ball milling method provided a new method for solid phase preparation of VO 2 (A). [ABSTRACT FROM AUTHOR]

Abstract: Nanocrystalline lanthanum monoaluminate (LaAlO3) powders were prepared by chemical coprecipitation using 25vol.% of NH4OH, 0.05M La(NO3)3·6H2O and 0.05M Al(NO3)3·9H2O aqueous solutions as the starting materials. Fourier transform infrared spectroscopy (FT-IR), thermogravimetric and differential thermal analyses (TGA/DTA), X-ray diffraction (XRD), Raman spectrometry, specific surface area (BET) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction (ED) were utilized to characterize the LaAlO3 powders prepared by chemical coprecipitation. The crystallization temperature of the LaAlO3 precursor gels precipitated at pH 9 is estimated as 810°C by TG/DTA. The XRD pattern of the LaAlO3 precursor gels precipitated at pH 8–12 and calcined at 700°C for 6h shows a broad arciform continuum exist between 24° and 32° and sharp peaks of LaAlO3 except the precursor gels precipitated at pH 9. For the LaAlO3 precursor gels precipitated at pH 9 and calcined at 700°C for 6h, the formation of the perovskite LaAlO3 phase occurs and the presence of crystalline impurities is not found. The crystallite size of LaAlO3 slightly increases from 37.8 to 41.5nm with calcination temperature increasing from 700 to 900°C for 6h. The LaAlO3 powders prepared by chemical coprecipitation have a considerably large specific surface of 30m2/g. The relative density greater than 97% is obtained when these nanocrystalline LaAlO3 powders are sintered at 1550°C for 2h. [Copyright &y& Elsevier]

• The eutectic Mg 2 Si in Al-11Mg 2 Si alloy was modified to spherical particles with 0.2 wt% Ca-Sb addition. • Adding 1.0 wt% Ca-Sb resulted in a microstructure transition from hypoeutectic to hypereutectic characteristics in Al-11Mg 2 Si alloy. • The 0.2 wt% Ca-Sb modified alloy exhibits an improvement in elongation to failure and ultimate tensile strength. • The modification mechanisms and the reasons for the enhanced mechanical properties were discussed in detail. The combined addition of 0.2 wt% Ca-Sb in Al-11Mg 2 Si alloy led to significant refinement of the eutectic Mg 2 Si from a coarse, needle-like morphology to spherical particles. Specifically, a further increase of Ca-Sb addition to 1.0 wt% resulted in the microstructure transition from hypoeutectic to hypereutectic characteristics. The refinement of eutectic Mg 2 Si could be attributed to the selective adsorption of Ca and Sb atoms on Mg 2 Si surfaces, which inhibited the growth of the eutectic phase in the preferential growth direction. Importantly, Ca and Sb elements were involved in the formation of heterogeneous nuclei for primary Mg 2 Si when Ca-Sb content increased to 1.0 wt%, which introduced the transition of composition from hypoeutectic to hypereutectic structures. Comparing to the unmodified alloy, the Al-11Mg 2 Si alloy modified with 0.2 wt% Ca-Sb exhibited significantly enhanced elongation to failure of ~7.9% (from ~1.3% of the unmodified alloy) and ultimate tensile strength of ~222 MPa (from ~180 MPa of unmodified alloy). The spheroidization of eutectic Mg 2 Si after complex modification is believed to be the underlying reason for the greatly enhanced tensile properties. [ABSTRACT FROM AUTHOR]

In this paper, hole-free, carbon-based all-inorganic CsPbI 3 perovskite solar cells (PSCs) with the structure of F-doped SnO 2 (FTO)/ZnO/CsPbI 3 /C are fabricated at a low temperature for the first time. Excess CsBr is added into CsPbI 3 precursor solution to obtain stable black phase CsPbI 3 at a low temperature (120 °C). ZnO is prepared by a spin-coating method at 120 °C. And then the C electrode is prepared by a doctor-blade method at 120 °C. The effect of different layers of ZnO on the performance of solar cells is investigated. The champion power conversion efficiency (PCE) of the solar cell based on 3 layers of ZnO is 10.95%, with a short-circuit current (J SC) of 17.66 mA/cm2, an open-circuit voltage (V OC) of 0.91 V and a fill factor (FF) of 68%, which is the best performance for hole-free, carbon-based all-inorganic CsPbI 3 PSCs fabricated at a low temperature, compared with the other reported results. The encapsulated device remained 91% of the initial PCE after being stored in a glove box for 5 months. For further application in flexible solar cells, the solar cells with the structure of PET/Sn-doped In 2 O 3 (ITO)/ZnO/CsPbI 3 /C are fabricated under the best parameter conditions and the PCE of 8.70% is obtained. ga1 • The champion power conversion efficiency (PCE) of the solar cell is 10.95%, which is the best performance of hole-free, carbon-based all-inorganic CsPbI 3 PSCs fabricated at a low temperature, compared with the other reported results. [ABSTRACT FROM AUTHOR]

An intense texture is usually developed in conventional Mg alloys after deformation, resulting in unsatisfactory formability at room temperature. In the present work, a low-alloyed and weak-textured Mg-1.5Zn-0.2Ca (wt.%) alloy that exhibited an advantageous combination of strength and ductility was developed, with an ultimate strength of ∼270 MPa and fracture elongation of ∼30%. The role of Zn addition in the texture and microstructure evolution was systematically investigated. The Mg-xZn-0.2Ca (x = 0.5, 1.0, 1.5, and 2.0 wt%) alloys with increasing Zn content stored additional deformation energy, which accelerated the static recrystallization (SRX) process and resulted in a gradual weakening of the annealing texture. The co-addition of Zn and Ca contributed to the random SRX nucleation and the enhanced solute dragging effects by decreasing grain boundary energy, leading to a weaker texture in the Mg-1.5Zn-0.2Ca alloy than that in the Mg-1.5Zn and Mg-0.2Ca alloys after annealing. The excellent ductility of Mg-1.5Zn-0.2Ca alloy was attributed to the simultaneous increment of uniform elongation and post-uniform elongation as Zn content increases, benefited from its weakened texture and improved failure mode, respectively. This work provides valuable insights into the development of novel low-alloyed Mg sheets with a weak texture, which possess great potential for direct forming to near-net-shaped products without tearing and fracturing. • A weak textured Mg-1.5Zn-0.2Ca alloy with balanced mechanical properties was developed. • Increasing Zn content facilitates SRX, leading to gradual texture weakening of the alloys. • Zn and Ca solutes lead to solute dragging effects and benefit texture weakening. • The weakened texture and improved failure mode benefit ductility of Mg-1.5Zn-0.2Ca alloy. [ABSTRACT FROM AUTHOR]

In the present work, CoCrFeMnNiV x (x = 0, 0.07, 0.3, 0.7, 1.1) high entropy alloy films were fabricated by magnetron co-sputtering. For low contents of V, typical face-centered cubic (fcc) peaks were identified in X-ray diffraction patterns. With the increasing V content, the diffraction peaks became broadened and the formation of an amorphous phase was promoted. TEM observations showed abundant nanotwins in the films with low V contents and the transition from fcc to the amorphous structure with the increasing V content. Mechanical properties of the films were studied using nanoindentation and micro-pillar compression tests. The films exhibited a high hardness ranging from 6.8 to 8.7 GPa. The serrated flow associated with shear banding showed in the stress-strain curves for films with x ≥ 0.3. When x = 0.07, the excellent yield strength of 3.79 GPa and ultimate compressive strength of 4.93 GPa were achieved with little sacrifice in ductility. The presence of nanotwins contributed to the strain hardening effect. Image 1 • We fabricated CoCrFeMnNiV x high entropy alloy films by co-sputtering. • Columnar nanograins and high density nanotwins were observed in films. • Nanograins and nanotwins contributed to strengthening with good ductility. • Detwinning behavior in films was observed during micro-pillar compression test. • The formation of an amorphous phase was promoted with the increasing V content. [ABSTRACT FROM AUTHOR]

In this paper, all-inorganic, hole-transporting-layer-free (HTLF), carbon-based CsPbIBr 2 planar solar cells with zinc oxide (ZnO) as electron-transporting materials (ETMs) were studied for the first time. The reported all-inorganic, HTLF, carbon-based cesium lead iodide dibromide (CsPbIBr 2) solar cells used titanium dioxide (TiO 2) as ETMs, which usually required a high sintering temperature of 500 °C. Here, ZnO ETMs were annealed at 120 °C. The highest power conversion efficiency (PCE) of 7.60%, with a short-circuit current (J sc) of 11.60 mA/cm2, an open-circuit voltage (V oc) of 1.03 V and the fill factor (FF) of 0.63, was obtained. Furthermore, the thermal and humid stabilities of the solar cells were studied. The perovskite solar cells were placed at 10% humidity and room temperature for 624 h and the PCE of perovskite solar cells only decreased by 10%. While the perovskite solar cells were placed at 80 °C and 0% humidity for 192 h, the PCE of the solar cells decreased by 4%. • All-inorganic, hole-free, carbon-based CsPbIBr 2 solar cells used ZnO as electron-transporting layers for the first time. • We have successfully fabricated an all-inorganic solar cell (FTO/ZnO/CsPbIBr 2 /C) with a conversion efficiency of 7.60%. • The humid and thermal stabilities of the device are relatively high. [ABSTRACT FROM AUTHOR]

Fabricating magnesium alloy sheets exhibiting superplasticity >500% by conventional rolling remains a challenge due to the difficulty in achieving fine-grained structure. Even more puzzling is the role of softened Mg 17 Al 12 particles locating at grain boundaries, which play a promoting or retarding effect on superplasticity at elevated temperatures, has not been understood so far. Here, fine-grained (∼3.0 μm) Mg–9Al–1Zn (AZ91) alloy with a high volume fraction of spherical Mg 17 Al 12 particles was prepared by conventional rolling. The rolled AZ91 alloy exhibits a high tensile strength of ∼370 MPa and ductility of ∼13% at room temperature. More importantly, high superplasticity of ∼563% and ∼735% is achieved at 250 and 300 °C, respectively. It is recognized that the deformation mechanisms of the Mg–Al–Zn alloys at elevated temperatures depend significantly on the amount of Mg 17 Al 12 particles. This work highlights the prominent role of a high volume fraction of Mg 17 Al 12 particles segregating along grain boundaries at elevated temperatures, which on one hand can effectively pin grain boundaries to retard grain coarsening, and on the other hand, are beneficial to relax the intergranular stress incompatibility, and hence significantly facilitate GBS behavior. The current study promotes significantly the industry application of high superplastic rolled AZ91 alloy sheets. [ABSTRACT FROM AUTHOR]

This paper reports on successful preparation of α-NaYF 4 single crystals co-doped with ∼1.9 mol% Tm 3+ and various concentrations (3.85 mol%, 7.69 mol%, 11.54 mol%, 15.38 mol%) of Yb 3+ by using a flux-Bridgman method. The fluorescence decay curve was measured to investigate the luminescent properties of the Yb 3+ /Tm 3+ co-doped α-NaYF 4 , and the energy transfer process from Yb 3+ to Tm 3+ ; the J-O intensity parameters of Tm 3+ were further calculated and analyzed according to the absorption spectra. Results show that, an intense 1.8 μm emission was achieved with Yb 3+ as sensitizer for Tm 3+ in the α-NaYF 4 single crystal under the excitation of 980 nm LD (Laser Diode) because of the strong energy transfer from Yb 3+ to Tm 3+ . The maximum emission intensity at 1.8 μm is obtained at about 15.38 mol% doping concentration of Yb 3+ when the concentration of Tm 3+ ions is fixed at ∼1.90 mol% in the current research. Moreover, the calculated maximum value of emission cross section at 1.8 μm is 1.63 × 10 −20 cm 2 for 3.85 mol% Yb 3+ /1.9 mol% Tm 3+ sample, and the obtained energy transfer rate ( W ET ) and energy transfer efficiency ( η ) are 1543 s −1 and 83.8%, respectively. Our analysis of the fluorescence dynamics indicates that electric dipole-dipole interaction is dominant for the energy transfer from Yb 3+ ions to Tm 3+ ions by using Inokuti-Hirayama’s model. [ABSTRACT FROM AUTHOR]

This study presented the one-step synthesis of sulphur (S) and nitrogen (N) dual-doped graphene using atmospheric thermal plasma. The doped graphene was synthesized in the magnetically rotating arc plasma with CS 2 as the sulphur source, N 2 as the nitrogen source and CH 4 as the carbon source. At the same reaction temperature, the concentrations of S and N in S and N dual-doped graphene were higher than those in S/ N -doped graphene, which indicated that the dual-doped mode had a promoting effect on the doping level. In addition, increasing the input power effectively increased the doping levels of S and N atoms, which were up to 15.0 at% and 6.9 at%, respectively, at an input power of 19 kW. The S and N dual-doped graphene displayed excellent microwave absorption capability, with an optimal reflection loss of −56.4 dB at 16.3 GHz, and the effective absorption bandwidth reached 5.7 GHz when the doping levels of S and N atoms were 12.2 at% and 5.1 at%. This simple and rapid method for preparing S and N dual-doped graphene might facilitate the application of heteroatom doped graphene. [Display omitted] • S and n dual-doped graphene was synthesized through a one-step process using atmospheric thermal plasma. • The highest doping levels of elemental S and N were 15.0 at% and 6.9 at%, respectively. • The optimum RL at 16.3 GHz was −56.4 dB and the EAB reached 5.7 GHz. [ABSTRACT FROM AUTHOR]

• A novel NaLa(WO 4) 2 /g-C 3 N 4 Z-scheme heterojunction was firstly constructed. • The directional transfer of charge from NaLa(WO 4) 2 to g-C 3 N 4. • NaLa(WO 4) 2 /g-C 3 N 4 exhibited high effective oxidation of NO under visible light. • A possible mechanism was proposed for NaLa(WO 4) 2 /g-C 3 N 4 oxidation of NO. [Display omitted] In this paper, a novel NaLa(WO 4) 2 /g-C 3 N 4 photocatalyst with Z-scheme heterojunction was synthesized for the first time, and the photocatalytic purification of NOx was used as an evaluation method of its activity. The structure was analyzed in depth by X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and other characterization methods. NaLa(WO 4) 2 and g-C 3 N 4 have obvious interfaces and successfully constructed a Z-scheme heterojunction structure. The combination of photogenerated electrons on the conduction band (CB) of NaLa(WO 4) 2 with holes on the valence band (VB) of g-C 3 N 4 leads to the accumulation of the remaining holes and electrons on the VB of NaLa(WO 4) 2 and CB of g-C 3 N 4 , and finally realizes the effective separation of photogenerated carriers and maintains the high redox ability of the catalyst. The NaLa(WO 4) 2 /g-C 3 N 4 composite catalyst has a highest NO purification rate of 47.18%, which is 16.51% higher than pure g-C 3 N 4. Moreover, the In-situ DRIFTS monitors the reaction intermediates and final products of NO on the NaLa(WO 4) 2 /g-C 3 N 4 heterojunction surface under visible light irradiation, and provides the corresponding reaction equations. This work provides a new type of photocatalyst that is easy to prepare and highly active, as well as a low-cost photocatalytic treatment technology to remove NO in the environment. [ABSTRACT FROM AUTHOR]

Thermal behavior and phase transformation of ZrO 2 –10%SiO 2 precursor powder prepared by a co-precipitation route without adding stability agent has been studied using different thermal analysis/thermogravimetry (DTA/TG), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), nano beam electron diffraction (NBED), high-resolution TEM (HRTEM) and energy-dispersive X-ray spectrometer (EDS). The TG results show that four weight loss regions were from 298 to 443 K, 443 to 743 K, 743 to 793 K and 793 to 1400 K. The DTA result shows that the ZrO 2 freeze-dried precursor powders crystallization at 1014 K. The activation energy of 993.7 kJ/mol was obtained for tetragonal ZrO 2 crystallization using a non-isothermal process. The XRD result shows that only a single phase of tetragonal ZrO 2 appears when the freeze-dried precursor powders after calcination between 1173 and 1373 K for 2 h. Moreover, when calcined at 1473 K for 2 h, the phase transformation from tetragonal ZrO 2 fully converted to monoclinic ZrO 2 occurred. [ABSTRACT FROM AUTHOR]

Abstract: Tetragonal phase NaLnW2O8 (Ln=Y, Yb, Er, Tm, Eu, Gd, Ho, Ce, and Sm) nanocrystals were successfully prepared via a hydrothermal method. It is found that large ionic radii of lanthanide ions and high reaction temperature are beneficial for the formation of NaLnW2O8. The upconversion luminescence properties of NaYW2O8:Yb3+/Er3+ and NaYW2O8:Yb3+/Tm3+ were studied under 980nm excitation. It is found that the luminescence intensity of 2H11/2 → 4I15/2 is much stronger than that of 4S3/2 → 4I15/2 as well as 4F9/2 → 4I15/2 in NaYW2O8:Yb3+/Er3+. Interestingly, there is no apparent change in the intensity ratio of 2H11/2/4S3/2 → 4I15/2 to 4F9/2 → 4I15/2 on Er3+ concentration. By analyzing the Raman spectrum, we suggested that the nonradiative relaxation of 2H11/2 → 4S3/2 is inefficient in NaYW2O8:Yb3+/Er3+, resulting in the strong 2H11/2 → 4I15/2 emission. The CIE coordinates of the green luminescence changed with excitation power. While for NaYW2O8:Yb3+/Tm3+, the CIE coordinates of the blue luminescence (0.14, 0.10) is almost unchanged with excitation power. In addition, the photoluminescence of NaYW2O8:Eu3+ excited at different wavelengths was studied in detail. [Copyright &y& Elsevier]

Abstract: In this study, the corrosion behavior of commercially pure titanium (c.p. Ti), Ti–6Al–4V and five new experimental Ti–Cr alloys was evaluated through open-circuit potential (OCP) and potentiodynamic polarization measurement in an artificial saliva containing fluoride. Electron spectroscopy for chemical analysis (ESCA) was used to characterize the composition of the passive films on the alloy after potentiodynamic polarization measurement. It was found that in standard artificial saliva the OCP increases with higher Cr content in Ti–Cr alloys. In 0.5% NaF artificial saliva, the OCP decreases with decreasing Cr in Ti–Cr alloys, and all but Ti–5Cr remain consistently higher than those of c.p Ti and Ti–6Al–4V. Linear polarization results show that artificial saliva and artificial saliva containing 0.5% NaF result in different corrosion behavior in Ti–Cr alloys, c.p.Ti and Ti–6Al–4V. The Ti–Cr alloys had greater resistance to corrosion in the fluoride-containing artificial saliva than c.p. Ti and Ti–6Al–4V, respectively. ESCA results verify that after potentiodynamic polarization a passive film consisting of TiO2 and Cr2O3 forms on the surface of Ti–Cr alloys. These experimental results show that the electrochemical corrosion behavior of Ti–Cr alloys in artificial saliva containing 0.5% NaF can be improved by increasing Cr content. This further indicates that Ti–Cr alloys could successfully be used for crown, bridge, and metal-ceramic restorations. [Copyright &y& Elsevier]

To attain superior electrochemical performance, a new series of high-entropy double perovskites are investigated as cathodes for solid oxide fuel cells. In this study, three PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5 double perovskites with different dopings of La, Pr, Sm, Gd, Nd, Y elements in A-site, high-entropy oxides (HEOs) cathodes are successfully prepared by EDTA-citrate combustion method and used as potential cathodes for SOFC at intermediate temperature. Three HEOs cathodes all form single phase double perovskite structure and match chemically well with Gd 0.2 Ce 0.8 O 2-δ (GDC) electrolyte. Linear thermal expansion coefficient of (La 0.2 Pr 0.2 Sm 0.2 Gd 0.2 Nd 0.2)Ba 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5 (LPSGNBSCF) at 200–1000 °C range is found to be moderate, 18.39 × 10−6 K−1. Typical anode supported SOFC with LPSGNBSCF cathode exhibits an excellent output performance of 1000 mW cm−2 with a lower polarization resistance of 0.3 Ω cm2 at 800 °C. These results might suggest that LPSGNBSCF can be a potential excellent cathode for SOFC. • High entropy PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ cathodes with A-site dopings are prepared. • SOFC with LPSFNBSCF cathode exhibits output performance of 1000 mW cm−2 at 800 °C. • LPSGNBSCF can be a potential cathode for SOFC. [ABSTRACT FROM AUTHOR]

MOF- or ZIF-derived carbon (MDC/ZDC) has attracted significant attention especially in catalysis applications, because well-dispersed metal or oxide nanoparticles over the MDC/ZDC matrix with retained MOF/ZIF porosity can be obtained with direct pyrolysis. Although it seems to be a facile approach, pyrolysis parameters could significantly alter the MDC/ZDC properties. However, an in-depth study on the pyrolytic factors has not been discussed. Herein, we manipulated ZIF structure, pyrolytic atmosphere, temperature, incubation time, and ramping/cooling rates for ZDC structural analyses. Compared to pure ZIF-67 derived carbon with only Co metal nanoparticles, it was observed that the carbonization process in core-shell ZIF-8@ZIF-67 (Z8@Z67) initiated the interdiffusion of reduced metal ions at the core-shell interface, which triggered the unique Zn-Co alloying behavior forming Zn 3 Co when they were in close proximity. The resultant intermetallic Zn 3 Co compound is unstable and has never been experimentally observed. By employing the in situ powder X-ray diffraction (PXRD) technique, we observed the fast-heating plus cooling process arrested or circumvented the phase segregation, and kept the metastable intermetallic Zn 3 Co. For the first time, we report a method to maintain it at ambient conditions, protected by the porous MOF derivative from ZIF pyrolysis. [Display omitted] • Well-dispersed Co nanoparticles is observed during Zn-Co core-shell ZIF pyrolysis. • Metastable phase Zn 3 Co is formed and preserved after core-shell ZIF pyrolysis. • The existence of Zn 3 Co can be controlled by ZIF pyrolytic ramping/quenching rates. [ABSTRACT FROM AUTHOR]

• A high strength and ductility AZT522 alloy was developed to compete with AZ91 alloy. • The AZT522 alloy had much finer as-cast microstructure than AZ91 alloy. • The AZT522 alloy exhibited superior rolling formability to the AZ91 alloy. • The annealed AZT522 alloy showed higher strength and ductility than AZ91 alloy. A novel Mg-5.34Al-2.23Zn-1.73Sn (wt%, AZT522 for short) alloy with high strength-ductility synergy was designed and fabricated via simple hot rolling and annealing treatment to compete with the commonly used Mg-9Al-1Zn-0.2Mn (wt%, AZ91) alloy. Different from the coarse microstructure of the as-cast AZ91 alloy, the as-cast AZT522 alloy has much finer microstructure, which consists of finer dendrites and smaller second phase particles. Hot rolling was carried out on the solution-treated alloys to effectively refine the microstructure and improve the mechanical properties. The results suggest that the AZT522 alloy shows better rolling formability. Then, the hot-rolled AZT522 alloy was annealed at the optimized parameter, i.e., 225 °C/1.5 h, leading to uniform fine grains with an average size of ~2.3 µm and numerous near-spherical precipitates (Mg 17 Al 12 and Mg 2 Sn) with a mean diameter of ~90 nm. Benefiting from the fine annealing microstructure, the novel AZT522 alloy finally exhibited high tensile properties at room temperature, i.e., ultimate tensile strength (UTS) of ~343 MPa, yield strength (YS) ~271 MPa, and elongation to failure (δ f) ~16%, which is a much better combination of strength and ductility than the annealed AZ91 alloy. This novel AZT522 alloy may provide a new insight to develop commercial high strength and ductility Mg alloys. [ABSTRACT FROM AUTHOR]

Achieving high strength-ductility synergy is a great challenge in low-alloyed Mg alloys. In this work, a new Mg–1.0Zn–0.45Ca–0.35Sn–0.2Mn (wt.%, ZXTM1000) alloy was designed and fabricated by sub-rapid solidification (SRS) to overcome the dilemma. After hot rolling and annealing, the new alloy sheet exhibited an excellent tensile yield strength (YS, ∼270 MPa) and elongation (∼21%). Microstructure characterization revealed that the high YS was mainly attributed to the fine grains (∼3 μm) and high density of spherical Ca 2 Mg 6 Zn 3 , Mg 2 Ca, and α-Mn precipitates. Moreover, the homogeneous grain size distribution, weakened TD-split texture and the activation of multiple types of slips contributed to the enhanced ductility. The findings demonstrate an effective way to fabricate low-alloyed Mg alloys with high strength and ductility by combining the SRS and hot rolling. Image 1 • A designed Mg–1.0Zn–0.45Ca–0.35Sn–0.2Mn (wt.%, ZXTM1000) alloy was fabricated by sub-rapid solidification. • The rolled and annealed ZXTM1000 alloy exhibits an good balance of yield strength (∼270 MPa) and elongation (∼21%). • EBSD-assisted slip trace analysis was utilized to determine the type of slips. • The reasons for the high strength-ductility synergy were discussed in detail. [ABSTRACT FROM AUTHOR]

The exploration of desirable structure is of positive significance for energy storage materials. In particular, morphology design of the electrode materials greatly affects the electrochemical performance. Herein, controllable synthesis of cobalt vanadate with various structures on 3D urchin-like CoO microspheres is achieved. By precisely controlling the vanadium content, we obtain cobalt vanadate with diverse structures, including 3D hollow nanocages, 3D nanocages connected to polygonal nanosheets, 2D honeycomb-like nanosheets, and 2D irregular nanosheets on CoO microspheres. Adjusting the content and structure of cobalt vanadate allows us to optimize its electrochemical performance. The optimized cobalt vanadate with a structure of hollow cages connected to polygonal nanosheets supported by CoO skeleton exhibits a superior energy storage capacity, and the final CoO@Co 2 V 2 O 7 electrode delivers an outstanding areal specific capacitance of 7.58 F cm−2 at 2 mA cm−2. In addition, the fabricated asymmetric supercapacitor (ASC) possesses an excellent energy density of 0.45 mWh cm−2 at 1.60 mW cm−2, and an outstanding capacitance retention of 84.65% after 5000 cycles. In a word, the proposed strategy of structure-controllable cobalt vanadate supported by CoO is promising for supercapacitor electrode materials. • Controllable synthesis of cobalt vanadate nanocages on 3D urchin-like CoO microspheres have been achieved as electrodes. • By introducing different vanadium content, the structure of cobalt vanadate can be adjusted to optimize its electrochemical performance. • An asymmetric supercapacitor with the optimized electrode possessing hollow cages showed impressive electrochemical performance. [ABSTRACT FROM AUTHOR]

Pursuing high-effective electrocatalysts is of paramount importance yet a great challenge, drawbacks such as irregular morphology, weak corrosion resistance, and poor anti-poisoning that limited their catalytic performance. Kinds of strategies have been developed to synthesize nanocatalysts with properties of low-cost, high-performance, and long lifetime. Pt-based catalyst is one of the most effective anodic materials for direct fuel cells (DFCs), especially towards ethylene glycol oxidation reaction (EGOR). Herein, we integrate the advantages of both composition and morphology to finally synthesize a series of PtBi chain-typed nanoflowers (NFs) serving as high-efficiency anode catalysts. The Pt 1 Bi 1 chain-typed NFs show much higher catalytic performances than Pt 1 Bi 2 , Pt 2 Bi 1 , and commercial Pt/C catalysts with the mass activity (1.17, 1.64, and 5.71 times higher, respectively) and retained mass activities (1.68, 3.26, and 13.1 times higher, respectively). Our present work opens a new way to promote the electrocatalytic activity and stability via synthesizing well-defined PtBi NFs with chain-typed structure. We also believe that the as-obtained PtBi NFs can be one of the candidates as promising anodic catalysts in DFCs. Image 1 • The PtBi chain-typed NFs have been synthesized by a facile one-pot method. • The PtBi chain-typed NFs provide abundant catalytic active sites. • The PtBi chain-typed NFs exhibits superior catalytic performance towards EGOR. [ABSTRACT FROM AUTHOR]

Abstract The present work revealed a potential to control the static recrystallization kinetics through regulating the feature of pre-existing Mg 17 Al 12 particles in Mg-Al-Zn alloys. The AZ31 (Mg-3Al-1Zn) with rarely dispersoids exhibits the fastest recrystallization rate, while the AZ61 (Mg-6Al-1Zn) with only fine particles (∼100 nm) recrystallizes slower than AZ91 (Mg-9Al-1Zn) containing Mg 17 Al 12 precipitates with scattered size distribution (ranging from less than 100 nm to above 0.6 μm). Especially, we found that coarse Mg 17 Al 12 particles in AZ91 are easier to trigger particle stimulated nucleation (PSN) at 275 °C than 175 °C, which compensates the strong recrystallization inhibition of fine dispersoids, leading to the recrystallization dramatically transforms from retarded to accelerated. Graphical abstract Image 1 Highlights • The precipitate feature notably affects the kinetics of static recrystallization. • Recrystallization of alloys with mixed particle size is sensitive to temperature. • Coarse particles in Mg-9Al-1Zn accelerate recrystallization at high temperature. • The study shows an efficient route to control the static recrystallization process. [ABSTRACT FROM AUTHOR]

Abstract A novel Mg-8Al-2Sn-1Zn alloy with a bimodal structure prepared by hard-pate-rolling (HPR) exhibits both higher tensile strength and ductility than its fine-grained counterparts prepared by conventional rolling. By delicate electron back-scatter diffraction (EBSD) analysis, we found fine grains with weak basal texture is beneficial for basal slip and favors initial deformation. Meanwhile, coarse grains with a strong basal texture could accommodate abundant newly generated dislocations, promoting work hardening after fine grains are saturated with dislocations. For the first time, individual roles of fine and coarse grains and their synergy effect on enhancing ductility in bimodal structured Mg alloys is clarified. Graphical abstract Image 1 Highlights • A bimodal grain-structured Mg alloy is fabricated by hard-pate-rolling. • The bimodal sample has higher strength and ductility than fine-grained samples. • The synergy effect of fine and coarse grains on enhancing ductility is clarified. [ABSTRACT FROM AUTHOR]

Abstract Magnetic Co-Ni-P nano-alloys were successfully prepared as microwave absorbers. Unfortunately, the poor dielectric properties severely restricted their microwave absorption performance. With the goal of high microwave absorption efficiency, one dimensional (1D) Co-Ni-P/SiC nanowire composites were firstly fabricated by means of an easy electroless plating method. A three dimensional (3D) conductive network can be constructed by the 1D composites. Results demonstrated that the 3D conductive network has significant effects on improving the dielectric loss of absorbers. The minimum reflection loss of the optimized composites can reach −45 dB at 12.5 GHz with a thickness of only 1.5 mm owning to their suitable impedance matching and multiple loss mechanisms. This work proposed a facile route to prepare 1D magnetic absorbers with higher absorption efficiency and their electromagnetic property and microwave absorption were also studied in detail. Graphical abstract Image 1 Highlights • Co-Ni-P/SiC nanowire composites are firstly fabricated via electroless plating. • 3D conductive network has significant effects on improving the dielectric property. • Co-Ni-P/SiC nano-composites exhibit outstanding microwave absorption ability. • Microwave absorption mechanism of Co-Ni-P/SiC nano-composites is elaborated. [ABSTRACT FROM AUTHOR]

Abstract Zr and Sb are simultaneously added to refine and modify primary Mg 2 Si in Al–20Mg 2 Si alloys. Compared with single addition of Zr or Sb, the combined addition of Zr and Sb can result in an enhanced refinement and modification effect on primary Mg 2 Si. The unique co-modification effect is mainly derived from the synergistic combination of Sb and Zr. Sb can involve in the formation of Mg 3 (Sb, Si) 2 particles and thereby can act as heterogeneous nuclei of primary Mg 2 Si, resulting in the uniform distribution and refined particle size of primary Mg 2 Si crystals. The role of Zr is also indispensable as it can decrease the solidification temperature interval of the primary Mg 2 Si phase, which could further refine the primary Mg 2 Si crystals and promote their complete growth. Moreover, the wear resistance of Al–20Mg 2 Si alloys is also improved owing to the special co-modification effect of Zr and Sb. Since primary Mg 2 Si can be optimized by enhancing heterogeneous nucleation and decreasing solidification temperature interval, such idea can be extended to guide the microstructure control in other alloy systems. Graphical abstract Image 1 Highlights • Fined and polygonal primary Mg 2 Si particles were obtained by adding Zr-Sb. • The wear resistance of Al–20Mg 2 Si alloys was improved due to fined primary Mg 2 Si. • Mg 3 (Sb,Si) 2 particles act as nuclei of primary Mg 2 Si particles. • Zr decreases the solidification temperature interval of primary Mg 2 Si phase. [ABSTRACT FROM AUTHOR]

Abstract In the present work, we investigated the influence of deformation temperature on the formation of a bimodal microstructure and tensile properties of a Mg–9Al–1Zn (AZ91) alloy processed by a single pass hard plate rolling (HPR) with a thickness reduction of 55% followed by a short time annealing. Microstructural examinations by electron backscatter diffraction (EBSD) reveal that there exists a narrow deformation temperature window, i.e. it is only feasible to achieve a desired bimodal grain structure in the AZ91 alloy when HPRed at ∼350 °C. It is mainly because that partial dynamic recrystallization (DRX) occurs easily in the sample HPRed at ∼ 350 °C, facilitating the formation of a bimodal microstructure consisting of coarse un–recrystallized grains (>∼70 μm) and fine recrystallized grains (<∼5 μm). In contrast, reducing deformation temperature to ∼300 °C results in a coarse unrecrystallized microstructure containing substantial sub structure, while elevating the deformation temperature to ∼400 °C leads to an almost uniform recrystallized grain structure. Especially, the formation mechanism for the bimodal grain structure at the optimum deformation temperature is explored in terms of Schmidt factors analysis for basal slips (SF basal ) for grains of different size scales. Moreover, the 350 °C HPRed AZ91 sample exhibits a better combination of strength (ultimate tensile strength = ∼374 MPa) and ductility (elongation = ∼19.6%), as compared to the 300 and 400 °C samples. It is mainly attributed to the typical bimodal grain structure and the relatively high SF basal featured by the fine recrystallized grains as well as the nanometer spherical particles distributing in fine grain interiors. Graphical abstract Image 1 Highlights • A bimodal grain structure of Mg–9Al–1Zn alloy was achieved by tailoring rolling temperature during hard–plate rolling (HPR). • The formation of bimodal microstructure was explored in terms of Schmidt factors analysis for basal slips (SF basal ). • The formation of bimodal grain structure generated a simultaneous improvement of strength and ductility. [ABSTRACT FROM AUTHOR]

This paper focuses on the magneto-optical properties of sillenite Bi 25 FeO 40 crystals rather than optofractive, optoelectronic, piezoelectric and other properties. The Bi 25 FeO 40 crystals with heavy Co3+ and Fe3+ co-doping were successfully grown into centimeter size by the top-seeded solution growth method. The thermal stability of crystal structure was improved. Annealing in oxygen atmosphere can greatly reduce oxygen vacancy defects, thereby improving the transmittance of the crystal. After doping Co3+ and Fe3+, Fe-O-Fe, Fe-O-Co and Co-O-Co superexchange interactionis formed in the crystal, which greatly enhances the magnetism of the crystal. Not only the magnetic but also the magneto-optical properties were significantly enhanced by co-doping Co3+ and Fe3+. • Centimeter scale magnetic ion doped Bi 25 FeO 40 single crystal was grown for the first time. • Co3+/Fe3+ co-doping greatly improved magnetic and magneto-optical properties of Bi 25 FeO 40. • Magneto-optical effect of Bi 26−x-y Co x Fe y O 40 crystal is much stronger than that of commercial YIG. • MCD ellipticity of Bi 24.1 Co 0.5 Fe 1.4 O 40 crystal reaches 290 deg cm−1 at 718 nm. [ABSTRACT FROM AUTHOR]

In the present work, Mg-9Al-1Zn-0.4Sn (AZT910) magnesium alloy sheets with a fine-grained structure (∼5 μm) and tilting basal texture were prepared by a 16-passes rolling process. Effect of tensile directions on properties and microstructural evolutions of the AZT910 alloy sheet at different temperatures, i.e. room temperature, 200 and 300 °C, respectively, were investigated by using three kinds of tensile specimens (rolling direction (RD), transverse direction (TD) and 45° towards RD). Experimental results showed that tensile properties exhibited a strong dependence on tensile directions at room temperature and 200 °C, while a negligible dependence at 300 °C. The anisotropic tensile properties imply that the deformation system of rolled AZT910 sheet consists of basal and non-basal slips at room temperature, and is a combination of basal slip, non-basal slip and grain boundary sliding/rotation (GBS) at 200 °C. The decrease of intensity and spreading of basal poles during tensile test and isotropic tensile properties indicates that GBS becomes the dominate deformation mechanism at 300 °C. The present work provides reference for the study of deformation behavior of novel superplastic magnesium alloy, and hence is of great significance for further application of wrought magnesium alloy. [ABSTRACT FROM AUTHOR]

In the present study, the application of hard–plate rolling (HPR) on the hard-to-deform Mg–7Al–5Zn (AZ75) alloy resulted in a homogeneous fine grained (∼6 μm) microstructure, where numerous micron/nano Mg 17 (Al, Zn) 12 precipitates with spherical morphology uniformly dispersed both at grain boundaries and within grain interiors. More importantly, the HPRed AZ75 alloy exhibited superior mechanical properties with a simultaneous high strength and ductility at room temperature, i.e. yield strength (YS) of ∼218 MPa, ultimate tensile strength (UTS) of ∼345 MPa and elongation of ∼19%, which was comparable to the commercial wrought magnesium alloys. According to the contribution from the several strengthening mechanisms estimated by simplified models, the grain boundary strengthening is the predominant mechanism for the high YS of the alloy. The high ductility is benefited from the strong work-hardening capacity resulted from Zn solid solutes and the presence of numerous well-dispersed nanosized precipitates as well as weakened texture. Moreover, the fine grained AZ75 alloy exhibits an optimum superplasticity of ∼615% at 300 °C at 1 × 10 −3 s −1 . It is attributed to the enhanced grain boundary slip (GBS) promoted by a well maintained fine grain structure resulted from the pining effect by numerous Mg 17 (Al, Zn) 12 particles segregating along grain boundaries during tension. The results will be helpful for the development and processing of high alloying element content Mg alloys with high strength and ductility as well as enhanced formability. [ABSTRACT FROM AUTHOR]

In this paper, a novel synthesis route of nano-scale and submicro-scale silicon carbide (SiC) whiskers on C/C composites was reported. H-PSO-DVB as the organic precursor was used to fabricate the SiC whiskers. The phase, chemical bonds and microstructure of the synthesized whiskers were analyzed in detail. It was shown that C/C composites were packed with a porous network consisting of random-oriented β-SiC whiskers when the preparation temperature is 1500–1600 °C. In view of that most of the SiC whiskers are tip flat or tapering, a vapor-vapor mechanism was used to explain the growth process of the whiskers. The differences of attenuated total reflection (ATR) and Raman spectra between the nano-scale SiC whiskers and bulk SiC were analyzed, which could be reasonably interpreted with the size confinement effect of nanomaterials. [ABSTRACT FROM AUTHOR]

Crystallization kinetics evaluated by the modified formula and optical properties of CdO and ZnO in 0.5ZnO-0.5CdO thin films have been investigated. The characterization used grazing incidence X-ray diffraction (GIXRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), high-resolution TEM (HRTEM) and ultraviolet–visible (UV–Vis) spectrophotometry. When the thin films are annealed at temperatures from 573 K to 773 K for 10–60 min, the GIXRD results show that all the films are composed of CdO and ZnO as major and second phases, respectively. In addition, a trace phase of CdSiO 3 appeared for thin films annealed at 723 K and 773 K for 45 and 60 min, respectively, while CdSiO 3 also appeared when annealing at 773 K for 30 min. The crystallinity of CdO increases with annealing temperature and duration, whereas the crystallinity of ZnO increases only slightly with temperature and duration. The activation energies of ZnO and CdO crystallization in 0.5ZnO-0.5CdO thin films are 49.51 kJ/mol and 112.45 kJ/mol, respectively. The crystallization of CdO and ZnO can be described by a modified formula: ln ( 1 1 − α ′ ) = [ 30 t × exp ( − 49.51 × 10 3 R T ) ] 0.24 and ln ( 1 1 − α ′ ) = [ 104820 t × exp ( − 112.45 × 10 3 R T ) ] 0.27 , for 573 K ≤ T ≤ 773 K and 10 min ≤ t ≤ 60 min, respectively. All films have an average optical transparency of nearly 80% in the wavelength range greater than 500 nm in the visible range, and the band gap energy of the thin films increases from 2.68 eV to 3.10 eV as the crystallinity of ZnO increases from 5.12% to 20.91% when the thin films are annealed for 60 min at 573 K–773 K and shows a blueshift effect. [ABSTRACT FROM AUTHOR]

Transitional metal selenides are regarded as promising electrode materials for battery-type electrodes on account of their superior electrical conductivity and high redox activity. It is expected to further improve their electrochemical performance by reasonable designing of the metal selenides' components and construction of novel nanostructures. Thus, in this article, self-supported sugar gourd-like (Ni,Co)Se 2 /(Ni,Co)Se 2 composites on carbon cloth are prepared by a facile approach. The theoretical calculations indicate that the (Ni,Co)Se 2 has higher conductivity and larger adsorption energy of OH- than that of NiSe 2 and CoSe 2 , thus effectively improving the kinetics of their electrochemical reactions. Thanks to synergetic effects from the active materials and their hierarchical nanostructures, the prepared sugar gourd-like (Ni,Co)Se 2 /(Ni,Co)Se 2 /CC nanoarrays achieve a high areal specific capacity of 1.278 mAh/cm2 (220.34 mAh/g) at 2 mA/cm2 and 88.9 % capacity retention after 5000 cycles. Furthermore, the flexible hybrid supercapacitor based on the designed nanocomposite demonstrates a high energy density of 0.7051 mWh cm−2 at the power density of 1.6303 mW cm−2 with extraordinary cycling stability. Such eminent energy storage performances strongly certificate that the obtained (Ni,Co)Se 2 /(Ni,Co)Se 2 /CC electrode is a potential battery-type electrode material for supercapacitor application. [Display omitted] • The sugar gourd-like (Ni,Co)Se 2 /(Ni,Co)Se 2 /CC nanoarrays were successfully designed. • Due to core-shell structure, nanoarrays reflect abundant active sites. • DFT provide theoretical support for the ameliorated electrochemical performance. • (Ni,Co)Se 2 /(Ni,Co)Se 2 /CC//AC HSC device achieves outstanding energy density. [ABSTRACT FROM AUTHOR]

A novel microsphere-like nitrogen-doped mesoporous carbon/nickel-cobalt layered double hydroxide (NMC/NiCo-LDHs-M) composites were successfully synthesized for the first time via a facile and cost-effective microwave method. The NMC/NiCo-LDHs-M electrode displays outstanding pseudocapacitance performances, including a high specific capacitance (2498 F g −1 at 1 A g −1 ), excellent rate capability and good charge-discharge stability, owing to the large surface area, appropriate pore size, rich mesoporous volume, low reaction resistance and high nitrogen amount. Moreover, an asymmetric supercapacitor using NMC/NiCo-LDHs-M as positive materials and NMC as negative materials was assembled to further investigate the electrochemical performances of NMC/NiCo-LDHs-M, which exhibited a high specific capacitance of 272.6 F g −1 at 1 A g −1 and outstanding electrochemical capacitance retention of 87.2% of initial capacitance after 10,000 cycles. These results indicated that the NMC/NiCo-LDHs-M microspheres were promising materials for high-performance supercapacitors and the microwave method was a potential approach for the design and preparation of diverse supercapacitor materials. [ABSTRACT FROM AUTHOR]

Oriented nickel sulfide (NiS) nanotube arrays were successfully in-situ fabricated on conductive glass substrate and used directly as counter electrode for dye-sensitized solar cells without any post-processing. Compared with Pt counter electrode, for the beneficial effect of electronic transport along the axial direction through the arrays to the substrate, oriented NiS nanotube arrays exhibit both higher electrocatalytic activity for I 3 − reduction and better electrochemical stability, resulting in a significantly improved power conversion efficiency of 9.8%. Such in-situ grown oriented sulfide semiconductor nanotube arrays is expected to lead a new class structure of composites for highly efficient cathode materials. [ABSTRACT FROM AUTHOR]

The rational design of hierarchical nanostructure consisting of multiple components with remarkable electrochemical performance is regarded as a significant technique for fabricating high-performance energy storage devices. Herein, self-supported tree-like (Ni,Co)Se 2 /Ni(OH) 2 heterogeneous nanoarrays on carbon cloth (CC) used as electrode materials of supercapacitors (SCs) are designed and synthesized by a multi-step approach. The (Ni,Co)Se 2 core can boost electron transport due to excellent conductivity, and the shell layer of Ni(OH) 2 nanoflakes improves the surface area. Profiting from the cooperative effects of two active materials and core-shell architecture, the tree-like (Ni,Co)Se 2 /Ni(OH) 2 composite delivers a superior capacity, outstanding rate capability and still retain 151.3 mAh g−1 after 3000 charge/discharge cycles. Meanwhile, the flexible hybrid supercapacitor (HSC) fabricated by the (Ni,Co)Se 2 /Ni(OH) 2 and activated carbon (AC) also manifests a satisfied energy density of 0.79 mWh cm−2 under 1.35 mW cm−2. Therefore, it can be considered that the as-prepared hierarchical (Ni,Co)Se 2 /Ni(OH) 2 nanoarrays are promising candidate for HSC devices in energy storage and conversion. • The tree-like (Ni,Co)Se 2 /Ni(OH) 2 core-shell nanoarrays were successfully designed. • The (Ni,Co)Se 2 /Ni(OH) 2 electrode exhibits superior electrochemical performance. • Due to construct heterogeneous core-shell structure, the hierarchical nanoarrays possess rich active sites. • The assembled HSC device achieves outstanding energy density. [ABSTRACT FROM AUTHOR]

Surface nanocrystallization and deformation-induced martensite in AISI 304 stainless steel subjected to multiple laser shock peening (LSP) impacts were investigated by means of EBSD and TEM observations. A layer of isometric nanocrystalline with a size of 50–300 nm has been formed on the surface after three LSP impacts. And a grain refinement mechanism induced by ultra-high strain rate plastic (>10 7 s −1 ) deformation during multiple LSP impacts in AISI 304 stainless steel (AISI 304ss) is proposed based on the microstructural observations. Both multidirectional mechanical twins and multidirectional martensites bands led to grain subdivision at the top surface during multiple LSP impacts. [ABSTRACT FROM AUTHOR]