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High-entropy alloys (HEAs) strengthened by dispersed oxide nanoparticles are considered potential structural materials used in advanced nuclear reactors. Herein, a novel Y-Si-O nanoparticle-strengthened near-equiatomic FeNiMnCr HEA was prepared via the powder metallurgy method. Microstructural characterizations revealed that the oxide dispersion-strengthened (ODS) FeNiMnCr HEA consisted of the face-centered cubic (FCC) matrix and high-density Y-Si-O nanoparticles (Y 2 SiO 5 and Y 2 Si 2 O 7). The average diameter and volume fraction of the nanoparticles were counted to be 21.3 nm and 1.02%, respectively. The grain size was reduced from 10.13 μm of the FeNiMnCr HEA to 0.79 μm of the ODS FeNiMnCr HEA. The ODS FeNiMnCr HEA showed a yield strength of 1125 MPa, an ultimate tensile strength of 1137 MPa, and a moderate elongation of 8.3% at room temperature. At 500°C, the ODS FeNiMnCr HEA also had a high yield strength of 662 MPa. Theoretical calculation showed that the high strength of the ODS FeNiMnCr HEA was mainly due to the grain boundary strengthening, dislocation strengthening, and precipitation strengthening. ● A newly designed ODS FeNiMnCr HEA with enhanced strength-ductility combination was fabricated by a powder metallurgy method. ● The alloy contained nano-sized grain structure and nano-oxide particles including Y 2 SiO 5 and Y 2 Si 2 O 7. ● The grain boundary strengthening, dislocation strengthening, and precipitation strengthening were the main reasons for the high mechanical strength of the ODS FeNiMnCr HEA. [ABSTRACT FROM AUTHOR]

In order to improve the hydriding/dehydriding kinetics of Ti-V-Mn alloys, Ti 37 V 40 Mn 23 +10 wt% Zr x Ni y were prepared. The microstructure, kinetic properties, and hydrogen absorption/desorption mechanisms were investigated. The findings revealed that Ti 37 V 40 Mn 23 exhibited single BCC phase structure, while the addition of 10 wt% Zr x Ni y facilitated the formation of C14 Laves phase. The Johnson-Mehl-Avrami model was adopted and demonstrated a good fit for all alloys. Ti 37 V 40 Mn 23 +10 wt% Zr 8 Ni 21 demonstrated optimal hydrogen storage kinetic properties, which exhibited a remarkable hydrogen desorption capacity of 2.15 wt% at 363 K. The promotion can be attributed to the increased presence of fresh surfaces and the enhanced C14 Laves phase proportion. Moreover, the dehydrogenation activation energy decreased from 109.91 kJ/mol to 55.20 kJ/mol after incorporating 10 wt% Zr 8 Ni 21 , indicating hydrogen atoms were easier to detach from the interior of the alloys. • The addition of 10 wt% Zr x Ni y promoted the formation of C14 Laves phase. • BCC phase transformed from a dendritic structure to a columnar crystal structure with the decrease in the Zr/Ni ratio. • The Johnson-Mehl-Avrami model demonstrated a good fit for all alloys. • After adding 10wt% Zr x Ni y , hydrogen desorption capacity increased and hydrogen ab-/desorption rate accelerated. • The dehydrogenation activation energy of Ti 37 V 40 Mn 23 +10wt% Zr 8 Ni 21 decreased to 55.20 kJ/mol. [ABSTRACT FROM AUTHOR]

Anchoring noble metal nanoclusters (NCs) on appropriate supports through structural engineering is an effective strategy for reducing the noble metal loading and improving catalytic activity for alkali hydrogen evolution reaction (HER). Generally, the local coordination environment of the active sites is key factor to regulate the interaction between the metal atoms and support. Here, a simple boronation method is proposed for preparing ruthenium nanoclusters anchored on B-doped Co 3 O 4 nanowires supported on Ni foam (denoted as Ru/B-Co 3 O 4) for alkaline HER. B embedded into Co 3 O 4 nanoarrays through B-O bonding can change the electronic structure between Ru active sites and Co 3 O 4. After optimizing electronic structure of Ru and Co sites, Ru/B-Co 3 O 4 showed remarkable activity for HER, with current density of 100 and 500 mA cm−2 at overpotential of 143 and 233 mV, respectively. The experimental and theoretical studies display that the embedding of B into Co 3 O 4 effectively induces the electron transfer from Co to Ru atoms by bridging O atom, leading to the formation of electron-deficient Co sites. The charge redistribution of Ru accelerates the cleavage of H-OH, which optimizes H* adsorption energy and finally promotes HER. This study provides further insight into the regulation of metal-support interaction for HER electrocatalysts. [Display omitted] • Ru nanoclusters anchored on B-doped Co 3 O 4 nanowires are obtained for alkaline HER. • B embedded into Co 3 O 4 can realize the electronic structure between Ru sites and Co 3 O 4. • The charge redistribution of Ru accelerates the cleavage of H-OH and promotes HER. • Ru/B-Co 3 O 4 requires 100 and 500 mA cm−2 at overpotential of 143 and 233 mV, respectively. [ABSTRACT FROM AUTHOR]

Abstract Cu 2 Se is considered as a potential thermoelectric material due to its excellent electrical properties and relatively high ZT values. However, the temperature-dependent phase transition and expensive experimental preparation approach hamper its practical application. In this work, a series of Cu 2 Se 1- x I x (x = 0, 0.02, 0.03, 0.04, 0.05) alloys were prepared by using the cheap and facile hydrothermal method in combination with vacuum hot pressing. The crystal structures of synthesized Cu 2 Se 1- x I x (x ≤ 0.04) are identical to the cubic β -Cu 2 Se. By doping with iodine, the thermoelectric figure of merit of Cu 2 Se could be greatly improved up to 1.1 at 773 K and the phase transition temperature was reduced to 380 K. Our results suggest a promising route to optimize the performance of Cu 2 Se-based materials for high performance thermoelectric applications. Graphical abstract Image 1 Highlights • Cu 2 Se 1- x I x alloys were prepared by using the cheap and facile hydrothermal method. • The phase-change temperature is greatly reduced by doping iodine. • Thermoelectric performance of Cu 2 Se 1- x I x can be well optimized. [ABSTRACT FROM AUTHOR]

Biomass walnut shell was used to prepare activated carbon (AC) through a carbonization treatment and an activation procedure with potassium hydroxide (KOH). AC showed hierarchical pores: 0.6 nm micropores, 2.7 nm mesopores and macropores with average diameter of 50 nm, providing a large specific surface area of 2318 m 2 g −1 . This highly porous AC was tested as a host material to encapsulate sulfur via a vapor phase infusion process. The developed AC-S electrode showed a high initial specific capacity of 1350 mAh g −1 and good capacity retention over 100 cycles at 0.1 C for lithium–sulfur battery. [ABSTRACT FROM AUTHOR]

The great variability of the additively manufactured quality is becoming a major challenge to limit its wide application. Here, we combine the high-throughput molecular dynamics simulations with the artificial neural network to search for the high surface quality and damage minimization of the selective laser melted (SLMed) FeCrNi multi-principal-element alloy (MPEA), based on the complex microstructure obtained from experiment characterization. By adjusting the laser scanning speed and laser power density, a large amount of data related to the surface roughness, dislocation characteristics, and residual stress in the SLMed MPEAs is obtained for optimizing the SLM process. Atomic simulation results show that there are various degrees of Cr segregation under different processing parameters, which leads to the uncertainty of residual stress distribution and dislocation characteristics. Thus, the surface roughness and subsurface damage is highly sensitive to the SLM parameters. According to the training results of the artificial neural network, the laser scanning speed plays a more key role in regulating the surface integrity and subsurface damage in the SLMed MPEAs. The overall prediction results exhibit that the relatively slow laser scanning speed effectively reduces the residual stress. Importantly, a complex relationship between the SLMed parameters and properties is built. The current work provides a predictive recommendation to optimize the quality and process design of the SLMed MPEAs with high surface integrity and low subsurface damage. • High-throughput molecular dynamics simulations and the artificial neural network are combined. • Effect of the scanning speed, and laser power density on surface integrity of the SLMed MEPA is systematically analyzed. • A extremely complex relationship between the SLMed parameters and surface quality is quantitatively built. • Considering different weight coefficients of performance, the selection strategy of processing parameters is determined. [ABSTRACT FROM AUTHOR]

For titanium aluminide (TiAl) alloys, the high cost mainly comes from the forming process since the workability of TiAl alloys is quite low. To optimize the workability, introduction of β phase is an effective way. In the present study, a novel TiAl material alloyed with cheap β-stabilizing elements, Mo and Fe, was developed. The deformation behavior of the new alloy was characterized, and further alloying with interstitial elements to improve the high temperature properties was explored. Results show that the designed Ti–45Al–3Fe–2Mo at.% alloy has a fine grain β-stabilized microstructure. It shows a wide forging window, providing the foundation for an industrial forging process. The good deformability is derived from dynamic recrystallization of β phase and deformation-induced β → α 2 + γ transformation. With the addition of 0.5% C, the creep properties can be significantly improved, which is mainly caused by the decrease in the amount of β phase and the precipitation of P-type carbides. [ABSTRACT FROM AUTHOR]

• A new phase β -PbGa 2 S 4 that crystallizes in a non-centrosymmetric space group of Pna 2 1 was synthesized. • The structure of β -PbGa 2 S 4 is composed of a framework [Ga 8 S 16 ]8− with hexagonal voids filled by Pb atoms. • β -PbGa 2 S 4 demonstrates moderate phase matching second-harmonic generation response and laser-induced damage threshold. [Display omitted] Nonlinear optical (NLO) crystals can produce tunable lasers through the direct second-harmonic generation (SHG) process, which is of great significance in modern laser technology. Herein, a new chalcogenide β -PbGa 2 S 4 (1) crystallized in space group of Pna 2 1 was synthesized via high-temperature solid-state reactions. Compound 1 is composed of a three-dimensional framework [Ga 8 S 16 ]8− with hexagonal voids filled by Pb atoms via covalent Pb–S interactions. Importantly, it exhibits promising NLO performances, such as phase-matchable SHG efficiency (0.6×AgGaS 2 @1200 nm and 0.1×AgGaS 2 @1910 nm), moderate band-gap (2.46 eV), suitable laser-induced damage threshold (3.0×AgGaS 2), and a broad IR transparency window (0.5–25.0 µm). SHG response of 1 is mainly attributable to the occupied S–3p and Ga–4p states and unoccupied S–3p and Pb–6p states. [ABSTRACT FROM AUTHOR]

Highlights: [•] LTCC composites are fabricated by borosilicate glass and AlN ceramic. [•] The samples are prepared at ambient pressure. [•] Densified samples are achieved at low sintering temperature. [•] Thermal conductivity of the samples reaches 5.9W/(mK). [•] The sample displays a good comprehensive property as it contains 40wt% AlN. [ABSTRACT FROM AUTHOR]

Abstract: In this work, the composites of LiBH4 and AlF3 were prepared and their hydrogen storage properties were investigated. The AlF3 addition to LiBH4 resulted in significant decreases in dehydrogenation temperature. All the xLiBH4 +AlF3 (x =1, 2, 3, 5) composites started to release hydrogen from about 100°C. The dehydrogenation of the composites was accomplished through several steps, depending on the molar ratio of LiBH4 to AlF3. A new phase Li3AlF6 was formed during the first dehydrogenation step, which further reacted with LiBH4. AlB2 was formed only at temperatures higher than 300°C. Li2B12H12 was detected as an intermediate. The dehydrogenation reactions have significantly reduced and thus favorable enthalpy changes. However, the reversibility of the composites needs to be improved. [Copyright &y& Elsevier]

Abstract: Monodisperse NiO octahedrons have been synthesized by heating NiCl2 solutions on the Si substrates at 400–500°C for 1h. The NiO octahedrons are single-crystalline with the body-centered cubic structure and have controllable sizes in the range of 166–257nm. Control over the size of NiO octahedrons was achieved by adjusting the heating temperature. The formation of NiO octahedrons results from the selective adsorption of Cl– ions on unsaturated Ni(II) sites of NiO (111) surface. The NiO octahedrons with exposed {111} facets show higher intrinsic photocatalytic activity than Degussa P25 TiO2, and the photocatalytic activity was enhanced with a decrease on the size of NiO octahedrons. [Copyright &y& Elsevier]

Abstract: In this work, the dehydrogenation kinetics of the 2LiBH4 +MgH2 composite under different hydrogen back pressures was studied. The applied hydrogen back pressure significantly influenced the hydrogen release rate of the uncatalyzed composite. Higher hydrogen pressures enhanced the nucleation of MgB2, resulting in better dehydrogenation kinetics and cycle stability. The composite with a CuCl2 catalyst demonstrated significantly improved dehydrogenation kinetics because the nucleation of MgB2 was promoted by heterogeneous nuclei. However, similar effects of hydrogen back pressure on dehydrogenation kinetics were also observed for the CuCl2-catalyzed composite. The extraordinary results suggest that hydrogen back pressure plays an indispensable role in the formation of MgB2, which determines not only the reaction pathway but also the kinetics of dehydrogenation for the 2LiBH4 +MgH2 composite. [Copyright &y& Elsevier]

Abstract: The mixtures of LiBH4 with halides of Ce or La in a molar ratio of 3:1 were investigated to explore their hydrogen storage properties. The ball milling of LiBH4 with chloride of Ce or La yielded Ce(BH4)3 and La(BH4)3, while fluoride of Ce or La did not react with LiBH4 during extended ball milling at room temperature. The dehydrogenation temperatures of the ball-milled mixtures were reduced to 220–320°C, which were much lower than that of pure LiBH4. The diborane emission during hydrogen release was observed at a low level. The dehydrogenation temperature is found to be affected by the composition of rare earth halides, but less influenced by ball milling time. The endothermic dehydrogenation reactions produced lithium halides, hydrides and borides of the corresponding rare earth element. Moreover, the LiBH4 +1/3(Ce, La)(Cl, F)3 showed partial reversibility through the formation of an unknown borohydride, allowing for a potential hydrogen storage system. [ABSTRACT FROM AUTHOR]

Abstract: Mg and Mg-based alloys are not only promising hydrogen storage materials due to their high storage capacities, but also potential reducing agents in the synthesis of sodium borohydride NaBH4, an attractive hydrogen source with 10.6wt% hydrogen content. In this study, the MgH2 formation kinetics in pure Mg and Mg–23.5wt% Ni was studied and correlated with NaBH4 synthesis kinetics. It was found that the hydriding kinetics of Mg–23.5wt% Ni was significantly improved owing to the fine laminar Mg/Mg2Ni structure. Ballmilling and surface treatment made the eutectic alloy absorb 2.0wt% hydrogen at 353K. When these materials were applied for the NaBH4 synthesis, it was found that the eutectic Mg–Ni alloy enhanced the NaBH4 formation kinetics at high temperatures. However, NaBH4 was not produced at 353K although MgH2 could be formed. [Copyright &y& Elsevier]

Abstract: Hydrolysis of sodium borohydride NaBH4 is a promising method for on-board hydrogen supply for fuel cells. In this study, the hydrolysis reaction was studied by starting with solid NaBH4 rather than aqueous borohydride solutions, and adding less amount of water in an attempt to explore the maximum hydrogen generation capacity. It was found that hydrogen could be liberated at very high rates and over than 90% conversion rates were achieved when the mole ratio of water to sodium borohydride was not less than 4:1. The final hydrogen generation capacity was achieved as high as 6.7wt%. Materials such as CoCl2 or cobalt powder were found to be effective as the catalysts for the hydrolysis reaction at such reaction conditions. A large heat effect due to the exothermic reaction and a low melting point of NaBO2·4H2O led to the acceleration of hydrogen generation at the latter part of the hydrolysis process. It is thus promising to utilize these reaction conditions to achieve high hydrogen generation capacity by proper system design. [Copyright &y& Elsevier]

• Design a novel wide temperature electrolyte based on LiODFB for high voltage lithium-ion batteries. • The effect of the electrolyte on the cathode and anode was systematically studied. • The novel electrolyte shows enhanced high and low temperature performance. Spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) cathode with high voltage plateau at around 4.7 V (vs. Li/Li+) has attracted great attention. However, the lack of suitable electrolyte hinders its application. Although lithium difluoro(oxalate)borate (LiODFB)-based electrolyte has been proved to be suitable for high voltage electrolyte, traditional LiODFB-based electrolyte has poor low and high temperature performance. Therefore, we confirm that lithium difluorophosphate (LiPO 2 F 2 , LiDFP) as LiODFB-based electrolyte additive and dimethyl sulfite (DMS) as co-solvent significantly improve electrochemical performance of LNMO/Graphite full batteries at low and high temperature. Various physical and electrochemical techniques are used to investigate the effect of four electrolytes. The effect on cathode is mainly attributed to priority oxidation decomposition of LiDFP. The formed interface film can inhibit the dissolution of Mn2+, thereby improving the high temperature electrochemical performance. The effect on anode is that the interface film formed by LiODFB prevents continuous reduction of solvents and additive. The enhanced low temperature performance is due to the significantly increased ionic conductivity of DMS-containing electrolytes at low temperature. Besides, the formed of the cathode electrolyte interphase (CEI) membrane with low impedance by LiDFP can improve the kinetics of cathode/electrolyte interface, therefore enhancing the low and high temperature performance of LNMO/Graphite full cells. [ABSTRACT FROM AUTHOR]

Abstract: The direct borohydride fuel cell (DBFC) employs an alkaline borohydride solution as the anodic fuel. In this study, several Ni-based hydrogen storage alloys were studied as the anode materials for the DBFC. It was proved that hydrogen storage materials can absorb hydrogen during immersing in the borohydride solution. When used as the anode catalysts, these alloys usually showed less negative potentials than the pure nickel electrode. It was observed that hydrogen evolution was partially depressed through the electrochemical oxidation of the absorbed hydrogen at low borohydride concentrations. However, at high borohydride concentrations, the electrochemical reaction starting from borohydride species seems to be kinetically more favorable than the oxidation of the absorbed hydrogen. It was also found that the increases in specific surface area, surface activity and temperature improved the polarization properties of the alloy electrodes but hydrogen evolution was also increased. [Copyright &y& Elsevier]

Abstract: Borohydrides, a group of compounds with large hydrogen contents, can generate hydrogen readily by their hydrolysis reaction. In this study catalysts based on nickel and cobalt were developed to accelerate the hydrolysis reaction for hydrogen generation. Catalysts in four forms were tested for each metal: fine metal powder, metal salt, metal boride and Raney metal. It was found that the hydrolysis reaction was primary a zero-order reaction under the catalysis of these catalysts. Although cobalt showed higher catalytic activity than nickel in most cases, Raney Ni exhibited almost the same activity as the Raney Co. Among four chemical forms for nickel, Raney Ni demonstrated the best performance. Moreover, Raney catalysts made from alloys of nickel and cobalt showed even higher activity. The reaction on Raney metals was also characterized by a slowdown in hydrogen generation rate at low borohydride concentrations because of a mass transfer limitation. [Copyright &y& Elsevier]

A convenient method was developed to synthesize potassium borohydride by a mechano-chemical reaction of saline hydrides with dehydrated borates with a planetary ball mill. Among the tested saline hydrides, MgH2 was the most effective reactant for borohydride formation. In order to improve the borohydride yield, it was necessary to add an excessive amount of MgH2. When a 35% excess of MgH2 was added, potassium borohydride yield reached 100%. The borohydride formation was strongly dependent on the water content in reactants. When the water content in KBO2 samples was over 24.8 wt.% (equivalent to KBO2·1.5H2O), no borate was converted into borohydride by the mechano-chemical reaction. [Copyright &y& Elsevier]

We report the structural and physical properties of the Ta 10 Mo 35− x Cr x Re 35 Ru 20 high-entropy alloys (HEAs) with 5 ≤ x ≤ 13. These HEAs adopt a single tetragonal structure with the P 4 2 / mnm space group and show bulk Bardeen-Cooper-Schreiffer (BCS)-like superconductivity with the transition temperature T c up to 4.79 K. In the normal-state, a paramagnetic behavior is observed at low temperature for all x values due to the magnetic moment of Cr, which is found to be about one-third that in Cr metal. The T c depression rate with increasing Cr content is considerably lower than those in typical elemental, intermetallic, cuprate and iron pnictide superconductors, pointing to weak pair breaking in HEA superconductors by the Cr-3 d electrons. [Display omitted] • New tetragonal Ta 10 Mo 35−x Cr x Re 35 Ru 20 (5 ≤ x ≤ 13) HEAs are synthesized. • These HEAs are BCS-like superconductors with T c up to 4.79 K. • The magnetic moment per Cr atom is one-third that in Cr metal. • The magnetic pairing breaking effect by the Cr-3d electrons is weak. [ABSTRACT FROM AUTHOR]

• The FeCrNi MEA exhibits outstanding corrosion resistance with a low corrosion current density and noble breakdown potential. • The Cr-rich passive film formed on the surface of the FeCrNi MEA has few defects and strongly self-healing ability. • The thick chromium oxide formed on the grain boundary reduces the erosion in this area. The corrosion behavior and mechanism of a novel FeCrNi medium entropy alloy (MEA) prepared by powder metallurgy method in 3.5 wt% NaCl solution was investigated in this study. The results indicated that, compared with the 316L SS, the FeCrNi MEA exhibits outstanding corrosion resistance with a more positive breakdown potential (0.982 V SCE) and lower current density (8.317 × 10 − 8 A / c m 2). The passive film formed on the surface of the FeCrNi MEA is a Cr-riched and less defective film. At the same time, it also has a strong self-healing ability. Uniform microstructure and high Cr content are responsible for the good anti-corrosion performance. [ABSTRACT FROM AUTHOR]

• A novel precipitation strengthened FeCoNi MEA were synthesized through powder metallurgy method. • This Al6Ti7 MEA exhibits a high yield strength (796 MPa) with moderate ductility retention (20.3%). • The high strength is mainly attributed to the highly dispersed L1 2 nanoparticles, leading to precipitation strengthening. Strength-ductility synergy is considered as a long-standing contradiction in high-performance structural materials. Here, we fabricated an equiatomic FeCoNi MEA enhanced by nano-scaled L1 2 precipitates with outstanding mechanical properties via powder metallurgy (P/M) techniques. Compared with the FeCoNi MEA, this precipitation-strengthened FeCoNi MEA exhibits higher yield strength (796 MPa) and ultimate tensile strength (1268 MPa), and maintains moderate ductility of 20.3%. The strength improvement is mainly attributed to the grain refinement and dislocation pinning, caused by densely dispersed L1 2 nanoparticles with a volume fraction of about 48.7 vol%. This work provides a new strategy to design high-performance structural materials. [ABSTRACT FROM AUTHOR]

The elongation of high-strength copper alloy with tensile strength over 1300 MPa is generally less than 3%. In this paper, a novel Cu–20Ni–20Mn-0.3Nb-0.3Cr-0.1Zr (wt.%) alloy with high strength, high elasticity and high plasticity was prepared. Its tensile strength, elastic modulus and elongation is 1445 MPa, 147 GPa and 6.8%, respectively. On the basis of Cu–20Ni–20Mn alloy, microalloying Nb, Cr, Zr elements were added to restrain discontinuous precipitation and improve the properties of the alloys. By matching reasonable heat treatment process, a fine and highly uniform grain structure was obtained, which is the main reason for the increase of elongation. TEM and 3DAP results suggested that a large number of nanoscale NiMn precipitates are the main source of high strength in the alloy. The designed alloy has excellent comprehensive properties, which can be used for the preparation of precision sensing parts, elastic components. • A novel Cu–20Ni–20Mn-0.3Nb-0.3Cr-0.1Zr alloy with high strength, high elasticity and high plasticity was prepared. • Its tensile strength, elastic modulus and elongation is 1430 MPa, 140 GPa and 6.8%, respectively. • Microalloying Nb, Cr, Zr elements were added to restrain discontinuous precipitation and improve the alloy properties. [ABSTRACT FROM AUTHOR]

During the 120 years' development route of the nickel-based cathode, lots of efforts have been made to realize alkaline batteries with better performance. From the earliest Edison's nickel-iron battery to the modern nickel-based battery, progress is always accompanied by backtracking steps, exhibiting a spiral-rising feature. In the early researches, composition and structures of cathodes gained most of the attention while since the 21st century, the morphology of the active materials has taken most of the research areas. Although the research interests varied with the development of technology, the core issues in material science still exist and cause unfavored problems, including insufficient energy density, limited cyclability, and inadequate rate performance. This review mainly focuses on describing a comprehensive development story of the nickel-based cathode and explaining the reasons for technology alteration. In the end, issues needed attention for future researches are presented to provide practical guidance. Image 1 [ABSTRACT FROM AUTHOR]

Al/Cu/Ti/Cu/Al laminated composites were fabricated successfully by rolling with various rolling reduction at room temperature. It was found that the size of interior layer and Ti layer decreased gradually with the increasing of rolling reduction. The hardness values of Al, Cu and Ti layers increased linearly as the rolling reduction increased. The tensile tests showed that the larger rolling reduction was beneficial for the tensile strength increase, but the elongation decreased. The ultimate tensile stress of composite with 85% rolling reduction was 233 MPa. In-situ tensile test indicated that the crack initiated and propagated at Al/Cu interface. Due to the weak interface bonding strength and different plastic deformation capacity, the Al/Cu interface delaminated and the composites finally fractured. • Hardness function was proposed. • Tensile feature was in-situ investigated. • Fracture mechanism of composite was clarified. [ABSTRACT FROM AUTHOR]

Additive/subtractive hybrid manufacturing technology is a new technology that combines product design, software control, and additive manufacturing (AM) with subtractive technology, which can realize the metallurgical bonding of dissimilar materials. In this study, hybrid parts made of two materials were fabricated by depositing CuCrZr on a 316 L stainless steel substrate by selective laser melting (SLM) technology. The microstructure and mechanical properties of the SLM-ed CuCrZr, 316 L matrix components and the 316 L/CuCrZr interface were studied. The microstructure of SLM-ed CuCrZr consisted of elongated columnar crystals that developed along the building direction, and the 316 L matrix material was characterised by large equiaxed grains. After the 316 L substrate was polished, there were no macroscopic cracks and only a few pores at the interface of 316 L/CuCrZr, and good metallurgical bonding was achieved. The complex and uneven metal flow occurred inside the molten pool because of the Marangoni effect under the action of the laser, resulting in drastic changes in the grain size at the interface. • CuCrZr alloy was fabricated by SLM on the 316 L substrate to achieve hybrid manufacturing. • Substrate surface state can influence interface of 316 L/CuCrZr. • Dendritic microcracks and pores are the main defects at the interface. • Difference in physical properties of materials and stress caused cracks. [ABSTRACT FROM AUTHOR]

Abstract Recently, high-entropy alloys (HEAs) reinforced with ceramic particles have attracted increasing attentions due to their excellent hardness, strength and wear resistance. In this study, AlCoCrFeNi-xNbC high-entropy alloy (HEA) coatings (x = 10, 20, 30 wt%) were prepared by laser cladding. The phase constituents, microstructure and mechanical properties of the HEAs were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), electron back-scatter diffraction (EBSD), transmission electron microscope (TEM), microhardness and wear resistance tests. Due to the high entropy effect, the AlCoCrFeNi HEAs composites comprise only simple BCC and FCC structure phases. The addition of NbC particles results in a decrease in the fraction of the FCC phase. NbC particles are mainly distributed at the grain boundary in the HEAs with the addition of NbC. NbC particles have an advantage on the inhibition of HEA grain growth due to a strong pinning effect. The microhardness and the wear resistance of HEA composite improved significantly with the addition of NbC particles. A good comprehensive mechanical properties was obtained at the HEA with the addition of 20 wt% NbC particles. For the 20 wt% NbC-adding HEA, the average Vickers hardness is 525 HV, the average friction coefficient value is 1.023 and the mass loss is 1.05 mg. Highlights • AlCoCrFeNi-xNbC high-entropy alloys are prepared and researched. • The addition of NbC particles restrains the formation of FCC phase. • The addition of NbC particles plays a role of grain refinement. • The addition of NbC particles increases the mechanical properties of the alloys. [ABSTRACT FROM AUTHOR]

Abstract Color-tunable semiconductor quantum dots (QDs) are highly attractive for a wide range of applications including imaging, sensing, and lighting. Herein, we reported a facile synthesis of copper-doped zinc sulfide quantum dots (ZnS:Cu QDs) with tunable emission colors, using a microwave-assisted one-pot reaction. 3-mercaptopropionic acid (MPA) was used as a stabilizer agent and sulfide source for the formation of ZnS:Cu QDs. The photoluminescence of ZnS:Cu QDs showed a clear red-shift as increasing Cu concentration, which can be controlled by microwave irradiation time. As increasing the irradiation time, the emission color (peak) of ZnS:Cu QDs changed from blue (500 nm) to green (540 nm), yellow (580 nm), and to orange-red (595 nm). The obtained ZnS:Cu QDs were highly luminescent, as evidenced by their high quantum yields. The potential utility of ZnS:Cu QDs as a novel lighting source was demonstrated in a near-UV chip-based white light-emitting diode. Highlights • A facile synthesis of Cu doped ZnS QDs via a microwave-assisted one-pot reaction. • Tunable emission colors was highly dependent on the amount of incorporated Cu + dopant. • The potential utility of these QDs was demonstrated in white LED applications. [ABSTRACT FROM AUTHOR]

Abstract In this work, laminated Al/Ti composites were fabricated by hot rolling at three different temperatures (400 °C, 450 °C and 500 °C). The deformation behavior and fracture mechanism of composites were studied by the in-situ tensile test. The results indicated that the ductile shear fracture (for 400 °C and 450 °C rolled specimens) and ductile delamination fracture (for 500 °C rolled specimen) were the main fracture failure modes of Al/Ti multilayers. Results shown that the tensile load and displacement of the 500 °C prepared Al/Ti were better than other samples due to the higher rolling temperature. The changes of slip lines and plastic bands were the main plastic deformation characteristics for the Al layer and Ti layer metals, respectively. The investigation found that the major crack nucleation type in Ti layer was fold belt cracking. The slip bands cracking, cross-slip cracking, particle interface cracking and grain boundary slide cracking were the primary crack nucleation patterns for the Al layer. Highlights • The width variable and width strain expressions were put forward. • The different plastic deformation characteristics of Al and Ti layer were analyzed. • The crack nucleation mechanism was discussed in detail. [ABSTRACT FROM AUTHOR]

We report our facile and efficient approach for synthesizing Co-Fe alloy based oxygen reduction reaction (ORR) catalysts, in which alloy nanoparticles are encapsulated in nitrogen-doped carbon nanostructures. The catalysts with high hierarchical porosities are fabricated at an appropriate temperature of 775 °C without a further acid leaching treatment after pyrolysis due to the use of ZnO nanoparticles as auto-removable templates. Co/Fe atomic ratio is found to greatly influence the ORR catalytic activity. The catalyst with Co/Fe = 1 exhibits the best catalytic performance by showing an ORR onset potential of 0.99 V and a half-wave potential of 0.87 V (vs. RHE) in 0.1 M KOH, as well as 0.98 V and 0.83 V (vs. RHE) in 0.5 M H 2 SO 4 , better than or approaching the performance presented by a commercial 28.6 wt% Pt/C catalyst. The Zn-air battery using the synthesized CoFe@N-C catalyst delivers a higher power density at ambient conditions by air-breathing than the one using the 28.6 wt% Pt/C catalyst. Relatively higher atomic concentrations of both Fe and Co as well as more graphitic nitrogen in the surface of CoFe@N-C detected by X-ray photoelectron spectroscopy (XPS) may account for its excellent ORR catalytic activities both in alkaline and acidic environments. • E onset = 0.98 V and E 1/2 = 0.83 V (vs. RHE) in 0.5 M H 2 SO 4. • Using ZnO as an auto-removal template. • a strong dependence of ORR activity on Co/Fe ratio in the catalysts. • the catalyst with Co/Fe= 1 offers the best ORR activity. • high surface metal concentrations account for the high ORR activity. [ABSTRACT FROM AUTHOR]

The precipitation mechanism of nano-sized and micro-sized Mg 2 Ni particles during hydrogen-induced decomposition of 18R-type long period stacking ordered phase is investigated. Nano-sized Mg 2 Ni particles adhere to YH 2 particles inside grains, while micro-sized Mg 2 Ni particles form at grain boundaries due to the segregation of Ni atoms. The interface energies are predicted to be 1.108–1.263 J/m 2 for Mg/Mg 2 Ni, 1.389 J/m 2 for YH 2 /Mg 2 Ni, and 1.536 J/m 2 for YH 2 /Mg, indicating that the adhesion of nano-sized Mg 2 Ni to YH 2 reduces the total energy of the system. The negative segregation energy of −0.194 eV proves that the segregation of Ni atoms is energetically favorable. [ABSTRACT FROM AUTHOR]

The plastic deformation of FeCuNi ternary alloys of BCC nanocrystalline subjected to compressive or tensile loading is considered via molecular dynamics (MD) simulations at low temperature, to reveal the solid solution effect on BCC metals. Deformation mechanisms at nanoscale have been well revealed for FCC nanocrystalline structure, however, it remains unanswered for BCC nanocrystalline structure. The increase of solute concentration promotes the nucleation of partial dislocation due to the reduction of stacking fault energy, and suppresses the motion of dislocation owning to the severe lattice distortion, which is beneficial to improving the strength and ductility of FeCuNi alloys. There is a critical solute concentration to determine the strengthening or the softening of FeCuNi alloys. Interestingly, the deformation twinning mechanism, instead of traditional dislocation mechanism, dominates the plastic deformation of BCC ternary alloys. In addition, it is clear to observe the phase transformation from BCC to HCP, full dislocation slipping, cross-slip, grain growth, and grain boundary (GB)/twinning boundary (TB) motion. Fracture behaviors of FeCuNi alloys reveal that the addition of Cu and Ni elements results in the larger fracture toughness. [ABSTRACT FROM AUTHOR]

Two N-containing hydrocarbon based polymers polyacrylonitrile (PAN) and polyaniline (PANI) were found to be able to destabilize LiBH 4 , a potential hydrogen storage material, resulting in larger hydrogen capacities of more than 10 wt% with peak dehydrogenation temperatures around 344 °C. The results suggest that a co-destabilization effect was achieved through the interaction of B H and C H bonds, which was further enhanced due to the presence of nitrogen atoms in polymers. After rehydrogenation of the dehydrogenated products, LiBH 4 was found to be regenerated to a large extent in both of the LiBH 4 +polymer composites. Detailed analysis including XRD, FTIR, DSC-TG-MS, HRTEM, Raman, XPS and solid-state 11 B MAS NMR was performed to elucidate the dehydrogenation and rehydrogenation mechanisms in these composites. The results provide considerable information about interaction mechanisms among B H, C H, N H and C N bonds and also shed lights on the enhancement of LiBH 4 dehydrogenation and reversibility. [ABSTRACT FROM AUTHOR]

The rationally designed semiconductor photocatalytic materials have attracted significant attention because of their huge advantages in the use of solar light. Herein, a series of direct Z-scheme heterojunction nanocomposites were synthesized via in situ growth of zinc indium sulfide nanosheets on ceria nanosheets (ZnIn 2 S 4 @CeO 2) and employed for effective photodegradation and Cr(VI) reduction. Advanced characterizations such as XPS, EPR spectra, and DFT calculations verified that the formation of direct Z-scheme charges transfer mechanism promoted rapid charge separation and retained strong redox capacity. As a result, the optimized ZnIn 2 S 4 @CeO 2 sample showed significantly promoted photocatalytic removal rates for tetracycline (TC) and Cr(VI) at a 3.7 and 4.5 times enhancement by comparison with the pristine ZnIn 2 S 4 , respectively. Additionally, after four consecutive cyclic tests, the as-synthesized nanocomposite exhibited remarkable photocatalytic activity and stability. The present work provides an integrated engineering strategy for Z-scheme photocatalyst systems with high photocatalytic efficiency and extensive applications. • A novel ZnIn 2 S 4 @CeO 2 heterojunction was successfully fabricated. • The composite shown superior photodegradation for TC and Cr(VI) reduction. • The enhanced activity was attributed to a direct Z-scheme charge transfer mechanism. [ABSTRACT FROM AUTHOR]

We demonstrate an excellent performance of nitrogen-doped ordered mesoporous carbon (NOMC) plated with metal cobalt for microwave absorption in the frequency range of 2–18 GHz. Spherical NOMC particles with a cubic Im 3(_) m symmetry are synthesized by organic-organic self-assembly of triblock copolymer, 3-aminophenol and hexamethylenetetramine (HMTA) in basic aqueous solution. The prepared NOMC particles possess uniform mesopores, a high specific surface area and a considerable N-doped amount. An electroless plating method is established to deposit cobalt layer on the surface of NOMC particles. Benefiting from the unique dielectric property of NOMC and magnetic property of metal Co, the resultant Co/NOMC composite shows an excellent microwave reflection loss ( R . L .) performance. Particularly in Ku waveband, the R . L . can reach −30 dB with lower thickness than 1.6 mm, and wide effective bandwidth ( R . L . ≤ −10 dB) can be obtained. The R . L . values below −15 dB can be achieved in the whole measuring frequency range by adjusting the absorber thickness. These results indicate that the Co/NOMC composite can become a promising candidate for lightweight microwave absorbing materials in a wide frequency range. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we explored the possibility of NaBH4 synthesis when Mg reacted with hydrous sodium borates under hydrogen. It was found that Mg could react with the water in molten hydrous borates to form MgO and release hydrogen, which can be used for NaBH4 synthesis. Then remained Mg would react with formed anhydrous borate to form NaBH4. NaBO2 conversion rate was decreased with increase of the crystalline water content in the hydrous sodium borates. Based on experimental results, a mechanism of NaBH4 formation when Mg reacted with hydrous sodium borates was suggested. [Copyright &y& Elsevier]

Abstract: In this work, influences of Na2O in compounds lying within the Na2O–NaBO2 composition domain on NaBH4 recovery have been investigated. It is found that Na2O plays different roles in NaBH4 formation. Na2O is beneficial in terms of NaBH4 formation and reaction kinetics when Al is used for NaBH4 recovery, but harmful to NaBH4 formation when Mg is used for NaBH4 recovery from compounds lying within the Na2O–NaBO2 composition domain. High borate conversion rates can be obtained when Mg reacts with compounds lying within the Na2O–NaBO2 composition domain with less Na2O or Al reacts with the compounds containing more Na2O. NaBH4 formation temperature depends upon the used metals. [Copyright &y& Elsevier]

• [Rb 4 Cl][Cd 11 In 9 S 26 ] was a novel noncentrosymmetric salt-inclusion Chalcogenide. • It presents a distinctive [Cd 11 In 9 S 26 ]3 − framework constructed by pseudo-T2-Cd 3 InS 10 and T2-CdIn 3 S 10 supertetrahedra. • It shows decent phase-matchable SHG response, moderate band gap and high LIDT. [Display omitted] Salt-inclusion chalcogenide is a promising infrared (IR) nonlinear optical (NLO) system for its potential in mitigating the incompatibility between second harmonic generation (SHG) efficiency and laser-induced damage threshold (LIDT). Herein, a new noncentrosymmetric salt-inclusion chalcogenide, [Rb 4 Cl][Cd 11 In 9 S 26 ] (1), was prepared by high-temperature solid-state method. It features a distinctive [Cd 11 In 9 S 26 ]3- host framework composing of pseudo-T2-Cd 3 InS 10 and T2-CdIn 3 S 10 supertetrahedra, which are rare in known salt-inclusion chalcogenides. Remarkably, compound 1 exhibits a phase-matchable SHG signal (0.23 times that of benchmark AgGaS 2), which mainly originates from the distorted CdS 4 and InS 4 tetrahedra in the host moiety. Moreover, it possesses moderate band gap (2.32 eV) and high LIDT (4.9 ×AgGaS 2). Such high LIDT may due to its small thermal expansion anisotropy. [ABSTRACT FROM AUTHOR]

A new compound NaIn 3 S 5 has been obtained in the CaS–In 2 S 3 /NaBr system via a reactive flux method. NaIn 3 S 5 crystallizes in the orthorhombic space group Pbam (No. 55) with a = 12.4963(8) Å, b = 16.0811(10) Å, c = 3.8041(2) Å, and Z = 4. The NaIn 3 S 5 structure is characterized by a three dimensional framework consisting of interconnected tripartite-octahedral [ In 3 S 8 ] ∞ 1 infinite chains, with Na + cations residing in the one-dimensional channels along the c direction defined by S(1), S(2), S(3) and S(4) atoms. The optical reflectance measurement shows a band gap of 2.18 eV for NaIn 3 S 5 . Electronic structure calculation by the CASTEP code not only indicates that NaIn 3 S 5 is an indirect band gap semiconductor, but also explains why its experimental band gap is close to that of β-In 2 S 3 . [ABSTRACT FROM AUTHOR]

• Thermally stable La-Ni-B composites were synthesized. • La-Ni-B composites consisted of amorphous La-B-O and Ni-B. • High and stable catalytic performance for dehydrogenation of MgH 2. • La-incorporation effectively inhibited crystallization and growth of Ni. In this work, we synthesized La-incorporated Ni-B amorphous composites and investigated their effects on enhancing dehydrogenation/hydrogenation properties of MgH 2. MgH 2 with 5 wt% 2La-3Ni-B demonstrated significantly improved dehydriding kinetics. About 6.0 wt% hydrogen could be released within 5 min at 300 °C. Moreover, no decrease in deydrogenation rate was observed within ten cycles. XRD, XPS, SEM and HRTEM examinations revealed that the La incorporation into Ni-B resulted in an amorphous La-B-O structure that could keep its disorder state up to 600 °C. The crystallization and growth of Ni dispersed in the La-B-O structure was significantly retarded. Also the alloying of Mg with Ni or La was not observed. As a result, the added La-Ni-B composites showed higher structural and catalytic stability than Ni-B during hydriding/dehydriding cycling of MgH 2 at high temperatures. [ABSTRACT FROM AUTHOR]

In this study, a medium-entropy alloy (MEA) was used as a new binder to fabricate diamond composite. The MEA base diamond composite (MEA-Comp) shows a much higher transverse rupture strength (TRS, 1453.5 MPa) and a stronger bonding interface than the referenced Co base diamond composite (TRS, 744.9 MPa). It is for the first time found that a (Ni, Co) 3 Al L1 2 -type phase was in-situ formed between diamond and the MEA matrix. The L1 2 phase is fully coherent with the diamond in orientation relationship of [001] L 1 2 //[001] Diamond and (010) L 1 2 //(010) Diamond. Thus, the metallurgical bonding between diamond and metal matrix can be greatly improved, resulting in an enhanced wearing performance. Additionally, chromium carbides (majority Cr 7 C 3 and minor Cr 3 C 2) were also in-situ formed in the interlayer between diamond and matrix. The interlayer composed of L1 2 phase and chromium carbides can also block the direct contact between diamond and metal matrix, which might slow down the graphitization of diamond under service condition. • A medium-entropy alloy base diamond composite with good properties was prepared. • The in-situ formed interlayer at interface consists of L1 2 phase and Cr-carbides. • The coherent L1 2 phase improves the bonding between diamond and metal matrix. • The interlayer blocks contact of diamond-matrix to reduce diamond graphitization. [ABSTRACT FROM AUTHOR]

Dynamic mechanical properties of the selected laser melting (SLM)-NiCrFeCoMo 0.2 high-entropy alloy (HEA) are further improved by controlling the molten pool structure and the generation of σ-phase precipitation particles. In this study, a split Hopkinson pressure bar (SHPB) was used for testing the dynamical mechanical properties of the quenched SLM-NiCrFeCoMo 0.2 HEA specimens. Microstructure and volume fraction of the σ precipitates were characterized by X-ray diffractometry (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and the small angle neutron scattering (SANS) technique. After heating to 800 ℃, holding for 8 h and water quenching, the molten pool boundary of the SLM-NiCrFeCoMo 0.2 HEA disappear, and the ultimate compressive strength and the impact energy of specimens reach 1970 MPa and of 217.45 MJ·m−3, respectively. Due to the segregation of Mo elements in the molten-pool boundary of the as-build SLM-NiCrFeCoMo 0.2 HEA, more σ precipitates tend to form at the residual molten pool boundary of the quenched SLM-NiCrFeCoMo 0.2 HEA. The σ precipitates play key role in strengthening of the SLM-NiCrFeCoMo 0.2 HEA. • Annealed SLM- NiCrFeCoMo 0.2 HEA has larger ultimate compressive strength and the impact energy. • Lots of σ precipitates generate at the residual molten pool boundary. • Small angle neutron scattering technique is used to analyze the volume fraction of σ precipitates. • The σ precipitates play key role in strengthening of the SLM-NiCrFeCoMo 0.2 HEA. [ABSTRACT FROM AUTHOR]

The thermodynamic properties of body-centered cubic Nb-V system are well described using the integrated methodology of first-principle calculations, cluster expansion and Monte Carlo simulations, where the contributions from chemical order, lattice distortion and lattice vibration are included. Lattice distortion yields important influence on the phase stability of Nb-V system, while the lattice vibration leads to relatively small effect although the magnitude of vibrational entropy is large compared to the configurational entropy. In addition, lattice distortion also strongly correlates with the order-disorder transition and the degree of short-range order. By accounting for the contributions from chemical ordering, lattice distortion, and lattice vibration, the present first-principle calculations predict a miscibility gap in perfect line with the available experimental data and CALPHAD simulations. The efficient computational methodology adopted in the present work provides a transport route for the effective description of phase stability at finite temperature for complex alloys. • The thermodynamic properties of Nb-V system are effectively described. • The contribution of lattice distortion decreases the transition temperature of Nb-V. • Predicted critical temperature of the miscibility gap agrees well with experiments. [ABSTRACT FROM AUTHOR]

CoCrFeMnNi-based high-entropy/aluminide laminate (HAL) composites were produced following the hot pressing diffusion sintering method. The microstructure of the samples was analyzed using the SEM, EDS, and EBSD techniques, and the results revealed that the diffusion reaction phases of the HAL composite consisted of a four-layer aluminide structure based on the Al 13 (Cr, Mn, Fe, Co, Ni) 4 phase. The diffusion behavior of iron dominated the resulting phase, leading to the formation of Fe-Al compounds. Under the influence of the hysteresis diffusion effect of high entropy alloys, Al 13 (Cr, Mn, Fe, Co, Ni) 4 phase layers (ASL I–III) with different grain sizes and growth orientations are formed due to the difference of diffusion rates at different interfaces. At the front end of the diffusion reaction, the aggregation layer of the secondary phase Al 9 (Fe, Co, Ni) 2 appears due to the segregation of Co and Ni elements. The growth kinetics model of HAL composites was explored, and it was observed that a mixture diffusion type controlled the growth of the aluminide layer via 'grain boundary and lattice diffusion'. The mechanical properties and failure modes of the HAL composites were investigated through quasi-static and dynamic mechanical tests. The fracture toughness reached 25 MPa·m1/2, and the main energy dissipation modes were the deformation of the ductile layer and the fracture of the hard, brittle layer. The dynamic impact failure modes were primarily deformation and 45% adiabatic shear bands, and the impact strength and energy consumption reached up to 1800 MPa and 2260 J/mm3. HAL composites with high alumina content exhibited prominent crack propagation and fragmentation properties under high-speed impact. The stress wave was significantly attenuated in the crushed aluminide layer, which significantly improved the energy absorption effect of aluminide. [Display omitted] • CoCrFeMnNi-based high-entropy/aluminide laminate (HAL) composites were fabricated. • The diffusion reaction phases consisted of a four-layer aluminide structure. • A mixture diffusion type controlled the growth of the aluminide layer. • The mechanical properties were intrinsically related to the thickness of the aluminate layer. [ABSTRACT FROM AUTHOR]

We report the results of structural, mechanical and physical property studies on two new carbides MoRe 2 C and WRe 2 C, which were not identified in previous Mo-Re-C and W-Re-C phase diagrams. These ternary phases adopt a face-centered cubic structure at ambient pressure likely with a disordered atomic arrangement. Due to the covalent bonds between transition metal and carbon atoms, MoRe 2 C and WRe 2 C exhibit high hardness values of 15.3 GPa and 13.7 GPa, respectively. Furthermore, these carbides are discovered to be bulk superconductors with very similar T c values about 4.50 K. The analysis of their specific-heat jumps points to a weakly coupled, fully gapped superconducting state. The electron-phonon coupling constant, upper critical field and coherence length are estimated to be 0.56, 5.3 T and 7.9 nm for MoRe 2 C, and 0.57, 6.3 T, 7.2 nm for WRe 2 C. Our results suggest that transition-metal-rich carbides provide a platform to study the link between configurational disorder, high hardness and superconductivity. • MoRe2C and WRe2C with a face-centered cubic structure are synthesized. • The disordered atomic distribution results in a medium configurational entropy. • MoRe2C and WRe2C have high hardnesses of 15.3 GPa and 13.7 GPa, respectively. • Both carbides are weakly coupled, fully gapped superconductors below 4.5 K. [ABSTRACT FROM AUTHOR]

Refractory high-entropy alloys (RHEAs) usually have a high strength at elevate temperatures. However, their oxidation resistance is inferior for practical applications. Here we proposed a eutectic design of compositionally complex eutectic alloy (CCEA) by adding 10 at. % Ta to the Al 2 Co 28 Cr 20 Fe 25 Ni 25 , the resulting alloy shows a good combination of mechanical properties and oxidation resistance, e.g. a yield strength of 764 MPa and an oxidation resistance rate of 0.0031 mg cm−2h−1 at 800 °C, which outperforms those of RHEAs. The excellent oxidation resistance is attributable to the formation of protective Cr 2 O 3 and CrTaO 4 layer at the surface, which prevents the matrix from further contact with O 2. • A novel, non-equiatomic compositional complex alloy with eutectic structure was prepared by powder metallurgy. • The alloy exhibited an oxidation rate of only 0.0031 mg cm−2h−1 at 800 °C. • The protective Cr 2 O 3 and CrTaO 4 layers generated during oxidation prevents further contact with O 2. • The Laves phase transformed into the Co 0.6 Ta 0.4 phase near the surface of the alloys above 1000 °C. [ABSTRACT FROM AUTHOR]

We report the structural and superconducting properties of ternary transition metal borides MoReB and WReB. Both compounds crystallize in the tetragonal CuAl 2 -type structure, in which the Re and Mo/W atoms share the same crystallographic site and form one-dimensional zigzag chains along the c -axis. The results of resistivity, magnetic susceptibility, and specific heat measurements indicate that these borides are weakly coupled, fully gapped, type-II superconductors. The superconducting transition temperature T c , upper critical field, and Ginzburg-Laudau parameter are determined to be 5.25 K, 2.1 T, 15.6 for MoReB, and 5.30 K, 2.0 T, 15.7 for WReB. Despite their nearly identical T c values, the Sommerfeld coefficient of WReB is more than 20% smaller than that of MoReB, suggesting that the electronic density of states at the Fermi level is not the dominant factor in determining T c. In addition, the upper critical fields of both MoReB and WReB exhibit an anomalous linear temperature dependence and possible origins are discussed. • In both MoReB and WReB, the Mo/W and Re atoms share the same crystallographic site. • Both borides are found to be weakly coupled, fully gapped, type-II superconductors. • T c of these borides is not determined primarily by the density of states at the Fermi level. • A linear temperature dependence of upper critical field is observed in both cases, ascribing to Fermi surface anisotropy or multiband effects. [ABSTRACT FROM AUTHOR]

We demonstrated a new approach to increasing response of Fe 2 O 3 nanoparticles and sea urchin-like nanostructures towards methanol, ethanol, formaldehyde, acetone, triethlamine and n-Butylamine by increasing number of surface Fe atoms having dangling bonds through hydrogenation. The surface Fe atoms having dangling bonds are believed to serve as the reactive atoms for sensing reaction, thus, a gas sensing mechanism at atomic and molecular level is presented for the first time. The surface unsaturated active Fe atoms can adsorb oxygen molecules, produce electrons and catalyze the chemical reaction of the adsorbed oxygen with target gas. Hydrogenation may be a universal approach to increasing gas sensing performances of metal oxides. The gas sensing mechanism can deepen comprehending electron transfer during the gas sensing process and offer guidance to design the gas sensing materials with higher performances. • Hydrogenation is successfully used to improve the sensitivity of α-Fe 2 O 3 gas sensors. • Density of unsaturated Fe atoms at the surface is increased by hydrogenation. • The unsaturated Fe atoms are regarded to act as an active site for sensing reaction. • They generate free electrons, adsorb oxygen and catalyze the gas sensing reaction. • Hydrogenation may be used to improve gas sensing properties of other metal oxides. [ABSTRACT FROM AUTHOR]

Research on near-infrared (NIR) emission of Tm3+ and Yb3+ co-doped upconversion (UC) materials has accepted many interests owing to delightful features for frontier applications. In this work, we focus on the preparation of pure NIR emission and the improvement of absolute sensitivity (S A) on temperature in Tm3+ and Yb3+ co-doped novel double perovskite Gd 2 ZnTiO 6 (GZT) phosphors. Upon 980 nm excitation, these phosphors perform dramatical NIR emissions, and the integral intensity percentage of NIR emission versus total visible emissions reaches up to 99.88%. A high S A value with 1.7351 K−1 at 473 K for the I 801 /I 650 is obtained via introducing excellent NIR emission. Besides, the S A value of non-thermally coupled levels is higher than that of thermally coupled levels. These results suggest that this kind of UC material may be a candidate for NIR imaging and temperature detection applications. Image 1 High sensitivity based on non-thermally coupled levels is received via utilizing intense NIR emission in Tm3+ and Yb3+ co-doped double perovskite GZT phosphors. • Upconversion properties of Tm3+ and Yb3+ co-doped novel double perovskite Gd 2 ZnTiO 6 phosphors are investigated in detail. • Intense and nearly pure NIR emission with high integral intensity percentage that achieves 99.88% is obtained. • High S A with 1.7351 K−1 at 473 K for N-TCLs is received via utilizing intense near-infrared emission. [ABSTRACT FROM AUTHOR]

LaB 6 is a unique plasmonic material, for which the localized surface plasmon resonance (LSPR) absorption band intrinsically lies in the near infrared (NIR) region. In this work, we synthesized spherical LaB 6 nanoparticles with a tunable size within 50–200 nm. The optical properties of these LaB 6 nanospheres were found to be sensitive to the thickness of surface oxide layer that was formed during the synthesis, purification and dispersion processes. In order to enhance the stability of LaB 6 nanoparticles in aqueous environment, LaB 6 @SiO 2 with a core-shell structure was successfully prepared. Both LaB 6 and LaB 6 @SiO 2 demonstrated low cytotoxity in biomedical tests when their concentrations were limited to 0.2 mg mL−1. The in vitro photothermal therapy experiment showed that 4T1 cancer cells were eventually apoptotic after being exposed to a 980 nm laser for 5 min at a considerably low power density of 0.82 W cm−2 and a low dose of 0.1 mg mL−1 for LaB 6 @SiO 2. The results suggest that these LaB 6 nanospheres are viable photothermal agents for biomedical applications. • Spherical LaB 6 nanoparticles were chemically synthesized. • The NIR light absorption of LaB 6 was sensitive to the surface oxide layer. • Core-shell LaB 6 @SiO 2 was prepared for biomedical compatibility. • Low concentrations of LaB 6 and LaB 6 @SiO 2 were biosafe. • LaB 6 @SiO 2 was effective agent for photothermal therapy. [ABSTRACT FROM AUTHOR]