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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]

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]

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]

• 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]

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]

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 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]

• [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]

• 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]

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]

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]

A novel layered (Ca 0.35 Sr 0.2 Ba 0.15 Na 0.2 Bi 0.1) 3 Co 4 O 9 high-entropy ceramic is prepared for the first time by the traditional solid-state reaction. The XRD, SEM-EDS and TEM data exhibit that the multi-component cations can be introduced into the Ca site to form a single-phase and homogeneous solid solution with highly preferential crystal orientation and multi-scale structural defects. The textured high-entropy ceramic, compared to the pristine Ca 3 Co 4 O 9 sample , shows a significantly increased electrical conductivity due to the higher carrier mobility derived from the c -axis selective orientation, and obtains an enhanced power factor of 0.27 mW·m−1·K−2. Besides, high entropy induced multi-dimensional lattice defects can act as the phonon scattering centers to effectively suppress the lattice thermal conductivity, and achieves an ultralow thermal conductivity of 0.87 W·m−1·K−1 as well as a peak figure-of-merit of 0.3 at 973 K, which is about 2.5 times larger than that of Ca 3 Co 4 O 9. Our work deeply reveals the impact of the microstructure on thermoelectric properties in a high-entropy ceramic, which may help to advance the understanding and design of high-entropy thermoelectric materials. • Single-phase (Ca 0.35 Sr 0.2 Ba 0.15 Na 0.2 Bi 0.1) 3 Co 4 O 9 high-entropy ceramic is prepared. • It shows c -axis preferential orientation and multi-dimensional structural defects. • Ultralow thermal conductivity (0.87 W·m−1·K−1) and enhanced ZT (0.3 at 973 K) are achieved. [ABSTRACT FROM AUTHOR]

Numerous theoretical and experimental studies suggest that the chemical ordering microstructure plays an important role for the strength and plastic deformation in the multi-principal-element alloy (MPEA). Despite the importance of this fact has been well confirmed, little is known about the influence of chemical ordering degree from the atomic scale to nano scale for the nanocrystal MPEA over a wide grain size range. In the present work, considering the abnormal local stacking fault energy originated from the heterogeneous chemical element concentration, the modified Hall-Petch relationship is elaborately established in MPEA, quite different from the traditional alloys. Additionally, the effects of the solid solution, local chemical ordering, and precipitation on the strengthening contribution and strain partition are evaluated. The increase of the chemical ordering degree improves the stacking fault energy and deformation gradient, as well as microrotation field. This trend leads to the yield strength owing to the formation of the slender shear bands. The geometry of the ordered structure is deformed and twisted to a certain extent, for the compatible plastic deformation. This work gives the atomic understanding of chemical-ordering-degree dominated strengthening mechanisms, to develop the strong and ductile MPEAs with desired properties. The data that support the findings of this study are available from the corresponding author upon reasonable request. • Influence of chemical ordering degree on strength is studied in MPEA over a wide grain size range. • Modified Hall-Petch relationship dependent upon stacking fault energy from heterogeneous chemical element is established. • Reasonable regulation of chemical ordering degree mediated deformation/strain partitioning could obtain high strength. [ABSTRACT FROM AUTHOR]

Exploring newly regulative strategies to design highly efficient electrode materials is of great importance for supercapacitors. Herein, we highlight an interfacial engineering strategy for fabricating NiMn-LDH/V 2 CT x /NF hybrids with heterogeneous structure via a simple hydrothermal reaction. Detailed analysis confirms that the interfacial effect between NiMn-LDH and V 2 CT x enables electron transfer from NiMn-LDH to V 2 CT x in the hybrid material, resulting in improved electrochemical reactivity. As expected, the optimal NiMn-LDH/V 2 CT x /NF-2 demonstrates much better specific capacity than that of its counterparts. Moreover, this strategy can be extended to NiFe-LDH/V 2 CT x /NF hybrids, further proving the coupling effect between MXene and LDH is beneficial for the electrochemical performance. This work presents a new pathway to design advanced materials for supercapacitors. [Display omitted] • Interface engineering of heterogeneous LDH/V 2 CT x MXene hybrids facilitates high reactivity and conductivity. • V 2 CT x nanosheets effectively prevent the agglomeration of LDH nanosheets, which ensure the full exposure of active centers. • LDH/V 2 CT x nanosheet arrays exhibit improved electrochemical performance for supercapacitors. [ABSTRACT FROM AUTHOR]

An increasing amount of nitric oxide (NO x) is being discharged into the atmosphere due to the development of industry and combustion of fossil fuels. Photocatalysis, as a green and renewable technology, has attracted increasing attention from global researchers to address environmental pollution caused by excessive NO x in air. g-C 3 N 4 is a metal-free organic polymer photocatalyst that has received widespread attention due to its unique physical and chemical properties. However, the photocatalytic activity of g-C 3 N 4 under visible light irradiation is limited by high photocarrier recombination, poor conductivity, and low visible light utilization. The construction of novel S-scheme heterojunction semiconductors based on g-C 3 N 4 is a promising strategy to enhance the photocatalytic activity. In this study, S-scheme CeO 2−x /g-C 3 N 4−x (Ce/CN) photocatalysts were synthesized by the thermal polymerization of melamine and Ce(NO 3) 4. The photocatalytic activity of the as-prepared photocatalysts was investigated for the removal of NO with visible-light irradiation. The photocatalytic efficiency of 4Ce/CN was about 1.7 times higher than that of g-C 3 N 4 with a low NO 2 yield. Material characterization and DFT analysis demonstrated that the enhanced photocatalytic activity was attributed to N and O dual defects, the excellent conductivity of CeO 2 , and the in-built field of the Ce/CN S-scheme heterojunction. [Display omitted] • S-scheme heterojunction CeO 2-x /g-C 3 N 4-x with dual defects were prepared by thermal polymerization. • The improved photocatalytic performance for removing NO is attributed to dual defective sites and the built-in electric field. • The synergistic effect of defects and heterojunction optimizes interfacial photogenerated charges dynamics and promotes the generation of reactive oxygen species. [ABSTRACT FROM AUTHOR]

A wide application of magnesium (Mg) alloys in electronic devices requires high thermal conductivity and mechanical properties simultaneously. Unfortunately, the strategies for increasing their strength, such as alloying, decrease their thermal conductivity. Aging treatment is an effective method to resolve the strength-thermal conductivity trade-off. In this study, the mechanical properties and thermal conductivity of previously designed as-cast Mg–Zn–La/Ce alloys were further improved by aging treatment. Mg–Zn–La/Ce alloys aged at 473 K for 20 h exhibit a good comprehensive property. The thermal conductivity, yield strength, and ultimate tensile strength of aged Mg 97.3 Zn 2.6 La 0.1 alloy and Mg 97.4 Zn 2.5 Ce 0.1 alloy reach 148.4 W/(m·K), 172.9 MPa, 218.7 MPa, and 155.3 W/(m·K), 172.1 MPa, 239.1 MPa, respectively. The effects of La/Ce addition and precipitation on thermal conductivity were analyzed from the aspects of intermetallic phases, precipitates, and solid solutions using transmission electron microscopy (TEM) observations and precipitation kinetic calculations. The addition of La or Ce has a positive effect on the thermal conductivity due to the formation of ternary τ 1 phase which reduces the supersaturation of the Mg matrix. The precipitation shows two opposite influences on thermal conductivity. The sharp reduction in supersaturation of the matrix enhances the thermal conductivity, but the dense precipitates hinder the free movement of electrons and phonons. ● The designed Mg-Zn-La/Ce alloys own good thermal and mechanical properties. ● The La/Ce can improve thermal conductivity due to the formation of τ 1 phase. ● The precipitation has both positive and negative effects on thermal conductivity. ● The predicted thermal conductivity of Mg-Zn alloy agrees with experimental data. [ABSTRACT FROM AUTHOR]

To improve the dynamic mechanical properties of the selective laser melting (SLM)-NiCrFeCoMo 0.2 high entropy alloy (HEA), dynamic impact experiments were carried out on this alloy with different characteristic molten pools. Melt pool structures of different special sizes can be obtained by adjusting the laser power and scanning speed during the SLM process. In this work, the split-Hopkinson pressure bar (SHPB) is used to conduct dynamic impact on the SLM-NiCrFeCoMo 0.2 HEA samples with different molten pool size. The X-ray diffractometer (XRD), the scanning electron microscope (SEM), the electron probes micro-analyzer (EPMA) and the transmission electron microscope (TEM) were used to characterize the microstructure and deformation characteristics of the of the molten pool. The SLM-NiCrFeCoMo 0.2 HEA shows high impact energy absorption density and compressive strength at high strain rate. Volume energy density (VED) refers to the power delivered by the laser per unit volume of material during a SLM process, which can affect the size of the molten pool formed. Mo-rich σ phase precipitations are distributed near the molten pool boundary. In the cooling stage of the SLM process, the center of the molten pool has a faster cooling rate than the molten pool boundary, so area near the boundary stays in the temperature range where the precipitation occurs for a longer time, which is the reason why the precipitates are concentrated near the boundary. The precipitation strengthening in the SLM-NiCrFeCoMo 0.2 HEA is considered by measuring the relationship between the molten pool structure and the precipitation distribution, considering the material as a composite of the precipitation dense region (PDR) and the precipitation free region (PFR), and the strength contribution of precipitation is estimated by mixing rules. [Display omitted] • Control the size of molten pool by adjusting the input volume energy density. • Mo-rich precipitates are concentrated near the molten pool boundary. • The uneven cooling rate causes the concentrated distribution of precipitates. • The precipitate around molten pool boundary improves the dynamic mechanical property. [ABSTRACT FROM AUTHOR]

Transition metal-based phosphides (TMPs) show great potential for hydrogen evolution reaction (HER). The fine regulation of the electronic structure of metal-rich phosphides is an effective and challenging strategy for better activity. Herein, a simple and effective molten salt treatment is designed to synthesize porous boron doped Ni 2 P rod nanoarrays (M-B-Ni 2 P) for alkaline HER. The molten salt treatment facilitates the formation of unique porous Ni 2 P rod nanoarrays with homogeneous boron doping. The synthesized porous M-B-Ni 2 P exhibit excellent catalytic performance in alkaline media, requiring only an overpotential of 217 mV to drive 100 mA cm−2, which is 79 mV lower than binary nickel phosphide (M-Ni 2 P). The boron doping not only optimizes the porous geometry to increase the number of active sites, but also regulates the electronic coordination to promote the dissociation of water and the adsorption and desorption of hydrogen atoms. In addition, the self-supported monolithic M-B-Ni 2 P electrode can operate at a larger current density of 100 mA cm−2 for at least 100 h. This study on realizing boron doping based on molten salt treatment provides a new strategy for constructing transition metal-based phosphides as electrocatalysts. [Display omitted] • The molten salt treatment facilitates the formation of unique porous Ni 2 P rod nanoarrays with homogeneous boron doping. • The boron doping optimizes geometry to increase active sites, and regulates the electronic coordination to improve reaction kinetics. • The porous M-B-Ni 2 P exhibit excellent catalytic HER performance in alkaline media. • The self-supported 3D electrode ensures the stability of the catalyst. [ABSTRACT FROM AUTHOR]

In this study, AlCrFeNiMn x high-entropy alloy coatings (x = 0, 0.5, and 1) were successfully prepared on a copper substrate by laser cladding. The influence of Mn addition was investigated on the phase constituent, microstructure, and mechanical properties of the HEA coatings. Due to the high-entropy effect, the AlCrFeNiMn x HEA coatings comprised only simple BCC and FCC structure phases. Moreover, the addition of Mn elements inhibited the formation of FCC phases due to the variation of ΔG mix , ΔH mix , δ, ∆x and VEC value. The addition of Mn leads to solute effect, so the grains were significantly refined with an increase in Mn content. When the Mn content was 0.5, good comprehensive mechanical properties were obtained with an average Vickers hardness of 625 HV, average friction coefficient value of 0.42, and a mass loss of 1.02 mg. • AlCrFeNiMn x HEA coatings are prepared on a copper substrate by laser cladding. • The addition of Mn inhibited the formation of FCC phase of the AlCrFeNiMn x HEAs. • The addition of Mn can significantly refine grains of the AlCrFeNiMn x HEAs. • The addition of Mn can improve the mechanical properties of the AlCrFeNiMn x HEAs. [ABSTRACT FROM AUTHOR]

In this study, Al-Cu alloy suitable for laser powder bed fusion (LPBF) is rapidly developed through casting and laser remelting. The microstructure of as-cast Al-Cu alloy is consisted of equiaxed grains, and it was significantly refined after remelting. The Vickers hardness in the remelted zone improved by approximately 33.7% compared with that of as-cast Al-Cu alloy. The effects of different element content on Al-Cu-Mg-Zr alloy were analyzed, and optimum alloy composition was obtained with Al-5Cu-2Mg-1Zr-0.3Mn-0.15Ti through comparing microstructure, the hardness and other properties after remelting. The nano-indentation hardness and Young's modulus of remelted Al-5Cu-2Mg-1Zr-0.3Mn-0.15Ti alloys were 1.86 and 86.7 GPa, respectively. The microstructure was dense without obvious crack after LPBF forming, and the tensile strength, yield strength and elongation values reach 483 MPa, 365 MPa and 13.4% after solution treatment. • The suitability of LPBF-fabricated alloys composition was judged by cast and laser remelting.. • The ultra-fine microstructure and Al2Cu dispersion distribution were observed in laser remelting alloy. • New composition Al-Cu alloy prepared by LPBF shows a dense structure and good mechanical behavior. [ABSTRACT FROM AUTHOR]

Thermal barrier coatings (TBCs) are widely used to protect high temperature structure parts against oxidation and corrosion. The failure mechanism study of TBCs is very important and the stress evolution is core content of failure mechanism research. In this work, a 8YSZ:Eu coating was produced via atmospheric plasma spraying (APS) method. Thermal cycling tests was carried out at 1300 ℃. The residual stress evolution of the coating was detected by a Eu3+ photoluminescence piezo-spectroscopy based on the relationship between stress and the peak position of 5D 0 →7F 2 transition of Eu3+ ions. The failure mechanism of the 8YSZ:Eu coating was also studied. The as-sprayed 8YSZ:Eu coating contains metastable t ´ -ZrO 2 and amorphous structure. The stress distribution is inhomogeneous with both compressive stress and tensile stress. After 1000 thermal cycles, the initial compressive stress changed to tensile stress due to the thermal expansion coefficients (TEC) mismatch and irreversible plastic deformation during thermal cycling. With thermal cycling going on, the compressive stress appeared again and the averaged tensile stress decreased due to the volume expansion caused by phase transformation of the t ´ -ZrO 2 to m-ZrO 2 and the formation of cracks. Formation of the thermally grown oxide (TGO), phase transformation, thermal expansion mismatch are factors for the coating failure. • A Eu3+ photoluminescence piezo-spectroscopy was used to measure the residual stress. • The residual stress distribution and evolution of the 8YSZ:Eu layer during thermal cycling was studied. • A 8YSZ:Eu coating was prepared by atmospheric plasma spraying and thermal cycling behavior was studied. [ABSTRACT FROM AUTHOR]

• The noble-metal-free CuII/CuI was used as cocatalysts via transient CuII/CuI centers. • The non-traditional LLCMT pathway was formed as a novel charge transfer channel. • The Cu species transient center can enhance the charge carriers separation efficiency. The earth-abundant copper species anchored on the -NH 2 of NH 2 -MIL-101(Fe) as noble-metal-free cocatalysts via transient CuII/CuI centers were obtained via a convenient synthesis technique to achieve excellent photocatalytic hydrogen evolution performance in the dye sensitization system. The prepared sample 6Cu-NM-101 exhibited the best hydrogen evolution activity of 5770.96 μ mol·g−1·h−1, which was 4.06 times higher than the original NH 2 -MIL-101(Fe). A series of characterization tests, especially the CV and the Auger Cu LMM, demonstrated that the transient CuII/CuI center played a significant part in the novel ligand to linker metal charge transfer (LLMCT) process. In other words, the electrons could transfer from the lowest unoccupied molecular orbital (LUMO) energy level of the excited state Eosin Y (EY*) to the transient CuII/CuI center to further accelerate the carrier transfer and separation rate. Our work provided a more convenient and effective strategy to prepare various earth-abundant metal ions based on MOFs as low-cost cocatalysts via transient metal centers to boost the photocatalytic hydrogen evolution performance. [ABSTRACT FROM AUTHOR]

• (PEA) 2 PbBr 4 with improved properties were obtained via CsBr additive; • Enhanced surface morphology and optical properties of modified (PEA) 2 PbBr 4 ; • Responsivity for 2D perovskite photodetector based on sol-gel method is 0.67 AW−1; • Rise time and decay time are about 0.28 s and 0.21 s; • Spectral wavelength selectivity of (PEA) 2 PbBr 4 based photodetector was accomplished. Wavelength-dependent responsivity and detectivity of cesium halides additive photodetectors based on two-dimensional perovskite: (C 8 H 9 NH 3) 2 PbBr 4 under 10 V bias. [Display omitted] Considering of cost-effective and simple assembly principle of organic-inorganic halide perovskite (OIHP), producing perovskites into polycrystalline thin films from precursor solution has proved to be appealing. In this paper, (C 8 H 9 NH 3) 2 PbBr 4 was fabricated based on C 8 H 9 NH 3 Br (PEABr) and PbBr 2 according to compositions in the vicinity of (PEA) 2 PbI 4 , and the two-dimensionally (2D) perovskite was obtained which entitled with superior photoelectric performance, excellent solution processability and flexible substrates compatibility. And hydrophobic nature of spacer cation of aromatic alkylammonium or a large aliphatic both with the highly consistent orientation of 2D perovskites are beneficial for reducing the grain boundaries density. Meanwhile, optimized (PEA) 2 PbBr 4 were obtained via CsBr additive. Systematic material characterizations manifested enhanced surface morphology, photoluminescence efficiency and carrier lifetime of the CsBr modified (PEA) 2 PbBr 4. Then related (PEA) 2 PbBr 4 based photodetectors exhibited a good responsivity of 0.67 AW−1 when detectivity approached 5.2 × 1011 Jones, and a large on/off ratio about 500 was obtained. Meanwhile, the devices possessed noticeable stability during the optical switch tests with the rise time and decay time about 0.28 s and 0.21 s for CsBr dopped devices illuminated by 385 nm under 10 V bias. More importantly, spectral wavelength selectivity of CsBr based photodetector indicated the potential utilization in ultraviolet detecting when a wide bandgap of 3.018 eV was obtained. [ABSTRACT FROM AUTHOR]

• ZnO nanorod arrays were prepared using hydrothermal assisted with PEI. • The photodetectors based on PEI-ZnO show a quick response time (~4 s) and high responsivity (~56 A/W). • The flexible devices display reliable stability and robustness under bending tests. • Raman and XPS spectra reveal the defect mechanisms on improved performance. [Display omitted] Investigations on the high-performance flexible ultraviolet photodetectors have been becoming one of the interesting research focuses in recent years. ZnO is considered as suitable material for ultraviolet photodetection due to its wide bandgap (~3.37 eV). In this work, ZnO nanorod arrays were prepared using the hydrothermal method at the temperature of 70 ℃ on flexible substrates. Polyethyleneimine (PEI) was added into hydrothermal solution as the growth additive to achieve the performance improvement of the ZnO nanorod arrays ultraviolet photodetector. SEM, XRD, absorption spectroscopy, Raman spectroscopy and XPS were employed to characterize the morphology, crystallinity, optical properties and chemical composition. The introduction of PEI adjusts the growth process of ZnO nanorod arrays and affects the distribution of defect states, which brings out the improvement of the optoelectronic performance of ZnO nanorod arrays ultraviolet photodetectors. Compared with pure ZnO, the higher photo to dark current ratio and responsivity, and quicker time response speed are demonstrated in the PEI-assisted ZnO nanorod arrays photodetectors. And more photoresponse parameters are also discussed and compared. Furthermore, the photodetectors also display outstanding mechanical flexibility and robustness under multiple bending cycle tests. Our work presents a potential approach for improving the optoelectronic performance of simple-operated flexible ultraviolet photodetectors. [ABSTRACT FROM AUTHOR]

• The {001} faced PbTiO 3 nanosheets have higher sensitivity than PbTiO 3 powder. • The sensitivity of PbTiO 3 nanosheets is further enhanced by hydrogenation. • The exposed Pb-PbTiO 3 (001) plane was found to be gas sensing active surface. • The surface 8-coordinated Pb atom is evidenced to act as a sensing active site. • It adsorbs oxygen, generates free electrons and catalyzes the gas sensing reaction. PbTiO 3 (PT) nanosheets exposed with {001} crystal faces have prepared by using TiO 2 nanosheets having {001} facets as a Ti source. The PT nanosheets have higher response to acetone, formaldehyde, ethanol and triethylamine than the commercial PT particles. Their response can further be increased by increasing density of the unsaturated 8-coordinated Pb atoms at Pb-terminated PT (001) surface through hydrogenating. The unsaturated 8-coordinated Pb atoms on the (001) surface of PT are evidenced to act the sensing active sites, and an sensing mechanism at atomic level is presented. As an active atom, the 8-coordinated unsaturated Pb atom can adsorb oxygen from air, create electron and catalyze the gas sensing reaction. This mechanism can deepen comprehending of the gas sensing nature of metallic oxides. The surface unsaturated active metallic atom engineering may be a very effective general strategy to enhancing performances of metallic oxide sensing materials. [ABSTRACT FROM AUTHOR]

• Sensitivity of {111} faced MnO octahedron is signally increased by hydrogenation. • This results from an increase in the density of unsaturated Mn atoms on the surface. • The unsaturated Mn atoms are evidenced to serve as an active site for gas sensing. • They can absorb oxygen, generate free electrons and catalyze the sensing reaction. MnO octahedrons with exposed {111} crystal faces have been synthesized in a solvothermal system of Mn(Ac) 2 and C 2 H 5 OH at 200 °C for 48 h. Formation of the MnO octahedron results from the selective adsorption of -OCH 2 CH 3 and -OH groups on the (111) crystal plane. Responses of the MnO octahedrons towards acetone, triethylamine, ethanol and n-Butylamine are enhanced by increasing numbers of the unsaturated 2, 3 and 5-coordinated Mn atoms on the (111) surface by removing surface C 2 H 5 O- and -OH groups through hydrogenation. Thus, the exposed Mn-MnO (111) face is found to be a gas sensing active surface, the unsaturated 2, 3 and 5-coordinated Mn atoms on the (111) surface are evidenced to be the sensing reactive atoms and a detailed sensing mechanism is presented. The unsaturated active Mn atoms produce electrons, adsorb oxygen and catalyze the sensing reactions. The mechanism can deepen the understanding of the nature of oxide semiconductor gas sensing and is helpful to the design of high performance gas sensing materials. [ABSTRACT FROM AUTHOR]

• Seven AlSi10Mg alloys with different construction angles were prepared and researched. • The grains in vertical planes change from columnar grains to irregularly arranged grains, and then to equiaxed grains. • The AlSi10Mg exhibites mechanical property anisotropy that is a result of grain structure, dispersed Si, and residual stress. In this study, seven AlSi10Mg bulks with different construction angles (0°, 15°, 30°, 45°, 60°, 75°, and 90°) were fabricated by selective laser melting (SLM). The effects of different construction angles on the microstructure and mechanical properties of AlSi10Mg alloys were investigated. Increasing the construction angle changed the laser track segments from an ellipse to a semi-ellipse and then to fish-scale, specifically again from a semi-ellipse to an ellipse, due to the decrease of the laser radiation area. Meanwhile, the grains in the vertical planes changed from columnar grains to irregularly arranged grains, and then to equiaxed grains. The 45° sample exhibited the highest hardness of 154.44 HV 0.1. The 60° sample had a good combination of strength and plasticity with a tensile strength of 463.54 MPa, yield strength of 283.37 MPa, and elongation of 9.25%. The observed mechanical property anisotropy of the current AlSi10Mg alloy was a result of the pores, equiaxed grain structure, ultra-fine equiaxed sub-grains, and working hardening. In addition, the difference in the sample microstructures was attributed to the construction angles and deposited layer area. [ABSTRACT FROM AUTHOR]

● Pitting corrosion of AZ31 Mg alloy was in-situ monitored under nature corrosion state by combining EN and AE techniques. ● Three corrosion stages were identified according to EN and AE analysis results. ● Detailed relationship between EN and AE parameters and different corrosion mechanisms is discussed. Pitting corrosion of AZ31 magnesium (Mg) alloy was in-situ monitored by combining electrochemical noise (EN) and acoustic emission (AE) techniques. The EN signals were analyzed by transient shape observation, Hilbert spectrum and recurrence quantification analysis (RQA) based on recurrence plot (RP). AE characteristic parameters including rise time, amplitude, absolute energy and peak count were adopted to classify the AE signals. According to the mutual information obtained by EN and AE measurements, three corrosion stages including film-forming process, pit initiation and pit propagation can be identified. The detailed relationship between the AE and EN parameters and different corrosion mechanisms is discussed. The main contribution of present study is to provide a feasible method to effectively monitor the self-corrosion process of Mg alloy. [ABSTRACT FROM AUTHOR]