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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]

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]

• 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]

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]

• [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]

Two-dimensional materials have attracted great attentions due to their novel properties and promising applications in opto-electronic and spintronics devices, but the advance on engineering suitable band gap and ferromagnetic behaviour is still undergoing. Here, the electronic structures and magnetic properties of NM -doped (NM =Pd, Pt, Ag, Au, Cu) ZnO monolayer are investigated using first-principles calculations. The results show that the formation of NM -doped ZnO monolayer is easier under the O-rich condition than under the Zn-rich condition. Furthermore, the band gap of the ZnO monolayer becomes narrowed after NM doping. Moreover, all NM -dopants induce the polarization of the ZnO monolayer, and the total magnetic moments are within 0.8–2.0 μ B. The origin is attributed to the spin states of NM - d xy , NM - d x 2 -y 2 and p y , p x of their neighboring O atoms. In addition, we found that the Ag-, Au-, and Cu-doped ZnO monolayers are ferromagnetic half-metals, while Pd- and Pt-doping cases are ferromagnetic semiconductors. The present results demonstrate that NM -doping is a proper way to tailor the electronic and magnetic properties of the ZnO monolayer so as to expand its utilization in nanoelectronics and spintronics. Image 1 • Noble metal-doped 2D-ZnO is most likely to form in O-rich environments. • Noble metal-doped can result in the enhance magnetism and the narrowed band gap. • The magnetic moment comes from the noble metals and their neighboring O atoms. [ABSTRACT FROM AUTHOR]

Exploring the interactions between precipitates and grain boundaries (GBs) is of great important to tailor the high-temperature stability and mechanical property of precipitate hardened alloys. However, the influence of precipitate on GB stability in high entropy alloys (HEAs) is still uncovered at nanoscale. In this work, we investigate the effects of precipitate size and temperature on grain boundary migration (GBM) using molecular dynamic simulations. The results show that the GB stability is improved with the increase of the precipitate size, especially at low temperatures. Compared with the traditional dilute alloys, the strong atomic lattice distortion exits in HEAs, resulting in the localized high tensile/compressive stresses. Thus, GB bends towards the indeterminate direction due to the lattice distortion, different with the case bending towards precipitate in the dilute alloys. In addition, the lattice distortion makes dislocation nucleate at random GB region in HEA, which is different from that in dilute alloys. High temperature reduces lattice distortion and relieves the localized high stresses, thereby inhibits the nucleation rate of dislocations from GB. These results provide the fundamental messages for designing novel HEAs with excellent thermal stability. • Influence of precipitates on GB stability at nanoscale is still uncovered in high entropy alloys. • Complex atomic stress field around precipitate leads to irregularly non-localized deformation of GB. • GB roughness increases due to stress field induced by precipitate and lattice distortion. • High temperature reduces lattice distortion thus relives localized high stress, thereby inhibit dislocation nucleation. [ABSTRACT FROM AUTHOR]

The species and morphology of the modified electrode material have an essential influence on its properties. Inspired by the morphology of the dendritic fossils, we obtained a porphyritic cobalt-nickel precursor material by a green preparation method without a template. Further studies showed that the precursor material was a composite of Ni&Co carbonates and hydroxides (NiCo 2 CO 3 (OH) 2), and the possible chemical component was M(CO 3) m ·[M(OH) n x ·yH 2 O (M = Co, Ni, m, n, x, y = 0～5). Moreover, this material exhibited electrochemical activity against ascorbic acid (AA), dopamine (DA), and uric acid (UA), enabling simultaneous detection of the three, with low detection limit, fast response and no interference between each other. It is foreseeable that such carbonate and hydroxide-rich precursor materials are also an essential source of modified electrode materials. Image 1 • Inspired by the morphology of the microporous fossil, a porous cobalt-nickel precursor material by a template-free method was prepared and analyzed. • The precursor is chemically rich in hydroxyl and carbonate functional groups, and the possible chemical formula is M(CO3)m·[M(OH)n]x·yH2O (M = Co, Ni, m, n, x, y = 0～5). • The precursors have good electrochemical activity for the neurotransmitter molecules UA, DA, and AA, and can simultaneously detect the three. [ABSTRACT FROM AUTHOR]

Refractory high entropy alloys (RHEAs) are promising high temperature structural materials because of their excellent high temperature strength and high melting point. With introducing secondary particles, the high temperature mechanical properties can be further improved. However, its poor ductility limits the industrial application. In the present work, a new ductile NbTaTiV RHEA-based composite reinforced with Ti-C-O particles were in-situ synthesized through spark plasma sintering (SPS). The composite exhibits excellent room temperature compressive properties with yield strength, ultimate strength and fracture strain of 1760 MPa, 2270 MPa and 11%, respectively. A model is presented to study the strengthening mechanism, and the theoretical calculation shows that the dramatically strength enhancement is mainly due to the in-situ formation of Ti-C-O particles. • A (NbTaTiV) BCC /Ti-C-O composite was in-situ synthesized through powder metallurgy method. • The composite exhibits desirable yield strength of 1.76 GPa and ultimate strength of 2.27 GPa with reasonable fracture strain of about 11% at room temperature. • The composite also maintains an outstanding yield strength of 685 MPa at 1000 °C. • A model was present to analyze the strengthening mechanism. [ABSTRACT FROM AUTHOR]

Different contents of carbon element (0-3 at.%) was added into CoCrFeMnNi high entropy alloys (HEAs) to prepare carbide-reinforced CoCrFeMnNi matrix composites. The effects of carbon on microstructures and mechanical properties were systematically studied. The CoCrFeMnNi HEA sheet without carbon showed fine recrystallized grains with a grain size of approximately 5 μm and contained Cr-rich sigma phase. The CoCrFeMnNiC x HEA sheets with 1.0 at.% and 3.0 at.% C presented fine recrystallized grains and a small fraction of elongated grains. A large number of nano-scaled carbides were observed in the carbon-containing HEA sheets. With the carbon content increasing from 0 at.% to 3.0 at.%, the strengthening of the α-fiber texture is more obvious, and tensile yield strength increased from 371 MPa to 792 MPa, however, the elongation decreased from 54% to 11%, respectively. The CoCrFeMnNiC 1 HEA sheet with a volume fraction of 2.9% nano carbides showed excellent balanced mechanical property, with tensile yield strength of 634 MPa and elongation of 38%. The increase of yield strength for the CoCrFeMnNiC 1 HEA was mainly ascribed to the combined effects of precipitation Orowan strengthening and dislocations strengthening. Precipitation Orowan strengthening is the primary strength contributor, with a value of approximate 157 MPa. • Cr-rich sigma phase was observed in C-free CoCrFeMnNi HEA sheet. • Nano-scaled M 23 C 6 carbides were found in C-containing CoCrFeMnNi HEA sheets. • The CoCrFeMnNiC 1 HEA sheet showed an excellent balance of strength and ductility. • Nano-scaled M 23 C 6 carbides provided the largest contribution to the increase of YS. [ABSTRACT FROM AUTHOR]

Abstract In this study, the effect of hot extrusion on the microstructure and anti-corrosion performance of LDHs (layered double hydroxides) conversion coating on AZ91D magnesium alloy was investigated by means of microscopic observation and electrochemical measurement. After hot extrusion, the refinement and rearrangement of the β-Mg 17 Al 12 phase promotes the microgalvanic effect in the formation process, and the increase of dislocation density, twin, grain boundary and texture accelerates the dissolution rate of the Mg matrix. Due to microstructural differences, the electrochemical activity of various specimens in the formation process can be ranked as the increasing series: as-cast < transverse < longitude. Therefore, a thicker and more compact LDH conversion coating is formed on the longitudinal section of the extruded alloy, indicating the highest anti-corrosion performance. Highlights • The CO 2 pressurization method is the most environmentally friendly method. • The microstructure of the alloy was combined with the formation mechanism. • The formation mechanism of effect for β-Mg 17 Al 12 phases was found. • The role of microgalvanic and electrochemical activity was confirmed. [ABSTRACT FROM AUTHOR]

Abstract A nanoscale petal-like α-Ni(OH) 2 /reduced graphene oxide (α-Ni(OH) 2 /RGO) composite was synthesized with the one-step microwave method. α-Ni(OH) 2 particles with sizes of approximately 200 nm are uniformly distributed on the reduced graphene oxide sheet in the sample. When used as an electrode for alkaline rechargeable batteries, the discharge capacity of the α-Ni(OH) 2 /RGO composite reaches 333.5 mAh/g at 0.2C and 247.1 mAh/g at 10 C, respectively, with an excellent rate capability. After 2000 cycles, the capacity of the electrode is insignificantly attenuated, indicating a high capacity retention and cycling stability. The outstanding electrochemical properties are attributed to the nanoscale petal-like structure α-Ni(OH) 2 anchoring on the RGO sheets, which facilitates ion diffusion and increases the active surface, which is effectively reacting with the electrolyte. The nanoscale petal-like electrode material fabricated in this study provides clues to address the problem of energy applications of high-performance alkaline rechargeable batteries. Highlights • Petal-like α-Ni(OH) 2 /RGO is prepared by one-step microwave method. • RGO plays an important role in determining the morphology of α-Ni(OH) 2 /RGO. • Compared to Ni(OH) 2 , petal-like α-Ni(OH) 2 /RGO has a superior electrochemical property. • Discharge capacity reaches 333.5 and 247.1 mAh/g at 0.2 C and 10 C, respectively. [ABSTRACT FROM AUTHOR]

Abstract Inconel 718 (IN718) superalloy has been fabricated by selective laser melting (SLM) technology, and the effects of the solution and double aging treatment on the microstructures and mechanical properties of the alloy have been studied. Under the same aging condition, the hardness of the IN718 superalloy first increased and then decreased with the increasing of the solution temperature. When the solution temperature was 980 °C, the average microhardness of the alloy was increased to 502 HV 0.2 , with 17.56% increase. With the solution temperature increasing, more short-rod δ phase (Ni 3 Nb) was precipitated at the grain boundaries and distributed homogeneously, and the γ′′ phase (Ni 3 Nb) and the γ′ phase (Ni 3 (Al, Ti)) were formed. The δ phase (Ni 3 Nb) can pin grain boundary, inhibit the grain growth and improve the mechanical properties. In addition, the corrosion resistance of the alloy decreased after heat treatment. After heat treatments, the formation of the second phase subsequently increased the number of corrosion microbatteries and reduced the anticorrosive ability of the alloy. Highlights • The anticorrosive ability of IN718 alloys decreased after heat treament. • The second phase improve the property, but decrease the anticorrosive ability. • Giving good comprehensive mechanical properties after heat treament. [ABSTRACT FROM AUTHOR]

In this paper, a hollow tubular Co 3 S 4 /NiS/FeS heterogeneous composite was prepared by an ordinary hydrothermal procedure. The inner Co 3 S 4 can act as the carrier of the outer NiS/FeS, and the outer NiS/FeS can effectively prevent the collapse of the inner Co 3 S 4 hollow structure, ensuring the durability of the structure and performance in the cyclic charge-discharge test. The strong electronic interaction between Co 3 S 4 and NiS/FeS significantly improves the catalytic activity. It shows a small 230 mV overpotential at 10 mA cm−2, which is superior to commercial RuO 2. The Zn-air battery assembled with Co 3 S 4 /NiS/FeS catalyst showed outstanding stability over 2700 cycles with a narrow voltage gap of 0.67 V at 3 mA cm−2. Flexible battery also combined based on this catalyst can generally be discharged/charged at each bending angle and the gap remained almost continuous. Furthermore, Co 3 S 4 /NiS/FeS also displays hydrogen evolution reactions activity, displaying a lower overpotential of 233 mV at 10 mA cm−2. In the overall water splitting, Co 3 S 4 /NiS/FeS is used as both anode and cathode electrocatalyst, which can reach 10 mA cm−2 at 1.52 V, and the performance remains steady for 50 h. In conclusion, Co 3 S 4 /NiS/FeS is a potential tri-functional catalyst for ZABs and overall water splitting. [Display omitted] • Hollow tubular Co 3 S 4 /NiS/FeS tri-functional catalyst was designed. • It exhibited high efficiency activity and long-term durability toward ORR/OER. • When used this catalyst in ZABs, it showed excellent high stability within 2700 cycles. • The assembled soft-packing flexible ZABs can maintain stable within 50 h. [ABSTRACT FROM AUTHOR]

With its unique structure and properties, Ti 3 C 2 T x MXene has shown great potential for application in anti-corrosion coatings in recent years. However, its good conductivity might accelerate the corrosion process if effective protective measures are not taken. Herein, we developed sulfonated polyaniline (SPANI)/imidazolium salts modified Ti 3 C 2 T x (I-Ti 3 C 2 T x) composites (SIT), which were synthesized by oxidative polymerization of o-aminobenzenesulfonic acid and aniline monomers in I-Ti 3 C 2 T x dispersion. The structure, chemical composition, and properties of epoxy (EP) coatings with different contents of SIT were evaluated by several techniques, such as SEM, TEM, XPS, XRD, FTIR, EIS, and SST (Salt Spray Test). The experimental results showed that SIT greatly enhanced the corrosion protection property of EP coating. Especially, the impedance of 0.5 wt% SIT/EP coating was maintained at 6.57 × 109 Ω cm2 after 180 days of immersion, which was much higher than that of other samples. Furthermore, LEIS test results evaluated the passivation behavior and protective effect of the coatings in the presence of artificial scratches. The excellent anti-corrosion performance of SIT/EP coatings was due to the synergistic effects of antioxidation stability, impermeability property, and self-passivation produced by the fabrication of such SIT 3D structure hybrid. • Sulfonated polyaniline (SPANI)/I-Ti 3 C 2 T x composites (SIT) were synthesized to develop a novel anti-corrosion additive. • SIT improved epoxy coatings exhibited outstanding corrosion protection ability. • The passivation effect by SPNAI could provide supplemental protection to the scratched position of the coatings. • The anti-corrosion mechanism produced by antioxidation stability, impermeability, and the passivation was proposed. [ABSTRACT FROM AUTHOR]

Hot processing is extremely effective in optimizing the microstructure of γ-TiAl alloy, and hot deformation mechanism is the decisive factor in the microstructure evolution. In this paper, hot compression tests under different conditions were carried out to investigate the characteristics of hot deformation behavior and deformation mechanism of Ti-48Al-2 Nb-2Cr alloy with near-γ microstructure. The Arrhenius constitutive model was established, and the predicted flow stress agreed well with the experimental value. Hot processing maps at different strains were constructed. High power dissipation efficiency (η) region which was suitable for hot working appeared in the temperature range of 1180–1210 ℃ and the strain rate range of 0.001–0.01 s−1. At the strain rates from 0.001 to 0.1 s−1, dynamic recrystallization (DRX) served as the primary softening mechanism of the alloy, which was closely related to the disordered transformation of α 2 →α. At the temperature above T α 2 → α and the strain rate of 1 s−1, flow softening of the alloy was mainly controlled by dynamic recovery (DRV). The occurrence of DRX in the lamellar structure can be promoted by the elevated temperatures and reduced strain rates. Discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) appeared in the γ and α/α 2 phases of the alloy deformed at the conditions corresponding to high η region. With the decrease of η value, DRX nucleation of the alloy under the relevant conditions was chiefly dominated by DDRX. • Hot working window is optimized based on hot processing map and DRX mechanism. • Deformation mechanisms under different conditions are discussed. • Phase transformations of α 2 → α and γ → α play significant roles in the DRX behavior. • Relationship between DRX nucleation mechanism and η value is explored. [ABSTRACT FROM AUTHOR]

Sodium vanadium oxyfluorophosphate is a class of high-stability, high-capacity and high-voltage cathode materials for sodium ion batteries. But its practical performance is severely constrained by the low electric conductivity. In this paper, high-valence Zr4+ is designed and applied to improve the electrochemical performance of Na 3 V 2 (PO 4) 2 F 2 O (NVPFO). A series of Na 3 V 2−x Zr x (PO 4) 2 F 2 O (0 ≤x < 1) are prepared by a facile solid-state method. X-ray photoelectron spectroscopy and energy dispersive spectroscopy mapping demonstrate Zr4+ is successfully doped into NVPFO. X-ray diffraction with Rietveld refinement indicates the lattice parameters and cell volume are increased due to the large ionic radius of Zr4+. Scanning electron microscopy and transmission electron microscopy images verify the particle size is slightly decreased and more uniformly distributed after Zr4+ doping, and the carbon coating layer is also well reserved. The optimal doping is found 4 at% by generating Na 3 V 1.96 Zr 0.04 (PO 4) 2 F 2 O, which shows a specific capacity of 128, 106, 85 and 55 mA h g−1 at 0.1, 1, 8 and 60 C, respectively. After 350 cycles at 0.5 C, the specific capacity is gradually reduced from 115 to 87 mA h g−1 corresponding to a capacity retention of 75.7%. Its Na+ diffusion coefficient is calculated more than one magnitude higher than un-doped NVPFO. [Display omitted] • Zr4+ is successfully doped into Na 3 V 2 (PO 4) 2 F 2 O during a facile sintering process. • The influence of Zr4+ doping on structure and performance is investigated. • The optimal performance is obtained when the Zr4+ doping amount is 4 at%. • The underneath mechanism is studied combining a variety of characterizations. [ABSTRACT FROM AUTHOR]

A novel non-equiatomic Al 15.85 Fe 11.15 Co 32.11 Cr 10.76 Ni 30.13 high entropy alloy (HEA) was fabricated via powder metallurgy (P/M) method. The Al 15.85 Fe 11.15 Co 32.11 Cr 10.76 Ni 30.13 HEA exhibits dual-phase microstructure consisting of face-centered-cubic (FCC) and body-center cubic (BCC) phases. The Al 15.85 Fe 11.15 Co 32.11 Cr 10.76 Ni 30.13 HEA has high compressive yield strength of 938 MPa and fracture strength of 3360 MPa, and still maintains moderate fracture strain higher than 40%. Also, the Al 15.85 Fe 11.15 Co 32.11 Cr 10.76 Ni 30.13 HEA has high strength of 518 MPa at the temperature of 600 °C. Microstructural characterization shows that a large number of L1 2 and B2 nanoprecipitates are uniformly dispersed in the FCC and BCC phases, respectively, contributing to the enhancement of the strength of the two phases. The effective combination of FCC and BCC phases eventually leads to the high strength of the Al 15.85 Fe 11.15 Co 32.11 Cr 10.76 Ni 30.13 HEA. This finding provides novel guidance for the development of high-performance structural materials with superior balance of strength and ductility for future industrial applications. • Novel Al 15.85 Fe 11.15 Co 32.11 Cr 10.76 Ni 30.13 HEA was prepared through powder metallurgy method. • The HEA exhibits dual-phase (FCC + BCC) microstructure. • Massive L1 2 and B 2 nanoprecipitates are embedded in the FCC and BCC phases, respectively. • The HEA exhibits high compressive yield strength of 938 MPa at room temperature. • The high strength is attributed to the hierarchically heterogeneous microstructure. [ABSTRACT FROM AUTHOR]