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An ideal photocatalyst should have high redox capacity, efficient charge separation, and large reaction surface area. However, it is an extreme challenge to construct a photocatalytic system with above three merits. Herein, the g-C 3 N 4 /Bi@Bi 2 WO 6 composite photocatalyst was prepared by simple wet chemical method. Then the separation pathway of photoinduced charges through the interface was explored by XPS, EPR and active species capture experiments, confirming that the Z-scheme charge transfer route was followed. The optimized composite photocatalyst exhibited the photocatalytic hydrogen production rate of 1219.3 μmol h−1g−1, which is 2.29 times that of pure g-C 3 N 4 (533.4 μmol h−1g−1). Moreover, the photocatalytic degradation rates of RhB and TC were 82.43% and 66.7%, respectively, which were 7.55 times and 1.92 times that of pure Bi 2 WO 6. Ultimately, the enhanced photocatalytic performances were attributed to the synergistic effect of 2D/2D coupling interface and the deposited metal Bi, which not only benefited the efficient charge separation and fast charge migration but also provided the large reaction surface area. In addition, surface plasmon resonance effect of metal Bi can boost the visible light absorption and broaden the light absorption range to the full spectrum. Our study provides a new idea to design high-performance Z-scheme photocatalyst for highly efficient utilization of solar energy. • The idea of construction Z-scheme heterojunction system have high redox capacity, efficient charge separation, and large reaction surface area. • The enhanced photocatalytic performances were attributed to the synergistic effect of 2D/2D coupling interface and the deposited metal Bi. • The SPR effect of metal Bi can promote visible light absorption and broaden the light absorption range. [ABSTRACT FROM AUTHOR]

Monodisperse PbWO 4 hierarchical microspheres have been fabricated through a hydrothermal method by using trisodium citrate and SDBS as surfactants. The as-obtained PbWO 4 spheres are well-dispersed with narrow size distribution and are assembled by many closely packed nanoparticles. During the synthesis process, the trisodium citrate and SDBS additives play a crucial role in controlling the particle size and morphology of the product. The as-obtained PbWO 4 :Ln 3+ (Ln = Tb, Eu, Dy, and Sm) hierarchical microspheres exhibit intense light emissions with different colors coming from different Ln 3+ ions under ultraviolet excitation, which might find potential applications in fields of optical displays, optoelectronic devices, and light emitting diodes. [ABSTRACT FROM AUTHOR]

Photocatalysis is an effective way to treat industrial wastewater. Therefore, the design of low-cost and high-activity photocatalysts is crucial for environmental remediation. Herein, a ternary Z-Scheme LaFeO 3 /MoS 2 /graphene nanocomposite photocatalyst was synthesized by a facile two-step hydrothermal approach and tested for the degradation of dye wastewater. To this end, graphene was employed as a substrate for loading LaFeO 3 nanospheres and MoS 2 nanosheets to act as an electron migration medium for Z-scheme heterojunction. The obtained LaFeO 3 /MoS 2 /graphene photocatalyst showed high efficiency and stable performance toward the degradation of methylene blue (MB), estimated to 16.5-fold higher than that of sole LaFeO 3. The enhanced photocatalytic activity was mainly attributed to the synergistic effect between LaFeO 3 and MoS 2 /graphene co-catalyst, leading to the expansion of the visible light absorption range and optimization of the redox potential. Most importantly, the closely contacted Z-scheme heterojunction interface between LaFeO 3 and MoS 2 /graphene facilitated the separation and transport efficiency of photogenerated carriers, as well as prolonged the lifetime of photogenerated carriers. In sum, these results look promising for the future design of highly efficient LaFeO 3 -based photocatalysts with Z-scheme heterojunction structures. [Display omitted] • MoS 2 /graphene co-catalyst decorated LaFeO 3 was synthesized by hydrothermal method. • The degradation efficiency of LFO-50 M-10 G is 16.5-fold higher than that of pure LaFeO 3. • Appropriate MoS 2 /graphene modification LaFeO 3 had constructed Z-scheme heterojunction. • Both the charge separation and the visible-light absorption had enhanced in nanocomposites. • The hydroxyl radicals played a critical role in degradation of MB. [ABSTRACT FROM AUTHOR]

Single phase of Tb-doped YPO 4 phosphors with xenotime structure were successfully synthesized via a polyacrylamide gel at different annealing temperatures (650–1050 °C). The crystal structure, thermal behavior and optical properties of the as-synthesized samples were investigated by XRD, TG-DTA, FT-IR, PL, and XPS. The effects of heat treatment on the structure and luminescence properties of samples were discussed. The PL spectra results reveal that the annealing temperature plays a key role in the luminescence properties of products. The samples obtained under 650–850 °C exhibit a strong green emission at 546 nm, attributing to the 5 D 4 - 7 F 5 transition of Tb 3+ , while the samples produced above 850 °C emit dominating blue lines at 381 and 415 nm, corresponding to the 5 D 3 - 7 F 6 and 5 D 3 - 7 F 5 transitions, respectively. The XPS results imply that a part of doping Tb 3+ ions may be oxidized to Tb 4+ on the high-temperature thermal treatment process, which could be the reason for the bluish color of Tb-doped YPO 4 phosphors. [ABSTRACT FROM AUTHOR]

Models for M-doped (M = B, C, N at O site, and M = B, Mg, Al at V site) VO 2 (M1 phase) were studied using the first-principles density functional theory electronic structure calculations to evaluate the effect of M (M = B, C, N, Mg, Al) doping on the band edges. Our results showed that the band gaps of E g2 for all M-doped VO 2 were smaller than that of pure VO 2 (M1 phase, 0.78 eV). The band gap of E g2 for C-doped VO 2 was the smallest (0.434 eV), which can be concluded that the C-doped VO 2 could be the best one for achieving good thermochromic energy-saving performance from the electronic properties. These findings will provide a new routine of modulating the phase transition of VO 2 for the experimental works. [ABSTRACT FROM AUTHOR]

Abstract: Phase-pure Ce-/Tb-doped and co-doped lanthanum stannates (La2Sn2O7) nanocrystals were synthesized by a co-precipitation process combined with hydrothermal techniques without any further heat treatment. The crystal structure, particle size, morphologies, and photoluminescence properties of the as-synthesized products were investigated by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and photoluminescence spectroscopy (PL). The as-prepared samples were single-phase cubic pyrochlore-type nanocrystals with a typical size of 10–20nm. PL spectra showed a dominating green-emitting line around 544nm attributing to 5D4–7F5 magnetic dipole transition for Tb3+ doped and Ce3+/Tb3+ co-doped La2Sn2O7 nanocrystals. Meanwhile, the concentration quenching phenomenon was observed in both La2−x Tb x Sn2O7 and La1.82−x Ce x Tb0.18Sn2O7 nanocrystals. Furthermore, an interesting enhancement of the energy transfer induced green emission was observed in the as-synthesized La1.82−x Ce x Tb0.18Sn2O7 nanocrystals. [Copyright &y& Elsevier]

Carbon based electrode materials, such as carbon nanotubes (CNTs) and graphene, exhibit an excellent potential for supercapacitor electrodes. Morphology control is an effective approach to create the abundant ion paths and highly porous structures of carbon materials. In this study, solvent-free CNTs fluid (CNTF) and graphene oxide (GO) were used to establish a facile fabrication of porous three-dimensional (3D) CNTs/graphene hybrid porous structures using a one-step self-assembly hydrothermal method. CNTF is hydrophilic and can form a homogeneous CNTF/GO aqueous solution. Moreover, CNTF acts as a cross-linker and spacer to connect adjacent graphene sheets and prevent the restacking of graphene. The unique 3D CNTF/RGO composite electrode exhibits a high specific capacitance of up to 412.8 F/g at a current density of 1 A/g; further, it displays a specific capacitance of 137.3 F/g even at a high discharge rate of 10 A/g. The specific capacitance remains at 89.6% of the initial value after 10,000 charging/discharging cycles. This solvent-free fluid technique has been achieved with the direct self-assembly of 3D CNTs/graphene materials in water and can be utilized in broad applications that are potentially feasible for other 3D carbon materials. • 3D-CNTs/RGO framework were synthesized by a facile hydrothermal self-assembly method. • Hydrophilic CNTF could connect adjacent graphene sheets and prevent the restacking of graphene. • Composite aerogel electrode presented excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

Cu 2 Zn 1− x Mn x SnS 4 (CMZTS) thin films with composition controllability and tunable band gap have been firstly prepared by sol–gel technique followed by a post-annealing treatment at 580 °С for 10 min in nitrogen gas atmosphere. Effects of Mn variation in CMZTS thin films with x = 0.0–1.0 on the morphological, structural, and optical properties have been investigated. XRD and Raman studies reveal the incorporation of Mn into Cu 2 ZnSnS 4 (CZTS) thin films, and demonstrate the structural transition from kesterite to stannite with increasing Mn content. SEM images show that compact, homogeneous and densely packed grains could be formed. Furthermore, UV–vis spectroscopy indicate that the band gaps of the CMZTS films can be tuned almost linearly between 1.23 and 1.51 eV with a small bowing constant of the band gap (∼0.10 eV), which confirms the good miscibility of the alloyed constituents in the crystal lattice. [ABSTRACT FROM AUTHOR]

Plasmon hot carrier devices have tremendous potential applications in broadband photovoltaics, photodetection, photocatalysis, and intelligent optoelectronics, as they have the ability to generate hot carriers with energy lower than the optical bandgap at Schottky junctions and broaden the spectral range. However, this is mostly challenged by the lack of effective methods for the separation, migration, and extraction of plasmon hot carrier. In this work, a Cu 2 O@Au-CsPbI 3 heterostructure was fabricated using facile low-temperature solution synthesis and spin-coating technique. The proposed heterostructure benefits from the simultaneous transfer of plasmon hot holes to Cu 2 O and hot electrons to CsPbI 3 , as well as enhanced charge separation driven by the built-in electric field at the p-n heterojunction interface. The heterostructure realizes remarkably enhanced light absorption, reduces carrier recombination, and further improves conversion efficiency. It exhibits a wide spectrum response of ultraviolet-visible-near infrared and achieves enhanced photodetection performance. The results suggest that Cu 2 O@Au-CsPbI 3 heterostructure is a promising candidate for optoelectronic devices based on the harvesting of plasmonic hot carriers. • Cu 2 O@Au-CsPbI 3 heterostructures were fabricated by a low-cost solution method. • The heterostructures can simultaneously transfer plasmon hot holes and hot electrons. • The p-n heterojunction accelerates the separation and extraction of hot carriers. • The Cu 2 O@Au-CsPbI 3 heterostructures exhibited an enhanced optoelectronic performance. [ABSTRACT FROM AUTHOR]

Abstract: Four different methods, i.e. hydriding combustion synthesis+mechanical milling (HCS+MM), induction melting (followed by hydriding)+mechanical milling (IM(Hyd)+MM), combustion synthesis+mechanical milling (CS+MM) and induction melting+mechanical milling (IM+MM), were used to prepare Mg2Ni-based hydrogen storage alloys used as the negative electrode material in a nickel–metal hydride (Ni/MH) battery. The structural and electrochemical hydrogen storage properties of the Mg2Ni-based alloys have been investigated systematically. The XRD results indicate that the as-milled products show nanocrystalline or amorphous-like structures. Electrochemical measurements show that the as-milled hydrides exhibit higher discharge capacity and better electrochemical kinetic property than the as-milled alloys. Among the four different methods, the HCS+MM product possesses the highest discharge capacity (578mAhg−1), the best high rate dischargeability (HRD) and the highest exchange current density (58.8mAg−1). It is suggested that the novel method of HCS+MM is promising to prepare Mg-based hydrogen storage electrode alloy with high discharge capacity and activity. [Copyright &y& Elsevier]

α-titanium alloys are extensively applied under cryogenic environment and thereby their cryogenic mechanical properties and service failures deserve to be deeply studied. Here, tensile behaviors and damage-fracture characteristics of Ti-2.5Cu α-titanium alloy were systematically investigated at liquid-nitrogen temperature (LT) plus room temperature (RT) for comparison. It is found that the LT samples possess superior strength and ductility concurrently. Both yield strength (σ y) and ultimate tensile strength (σ b) improve more than 70%, whilst total elongation at fracture (A) adds more than 33% in comparison with the RT counterparts. Meanwhile, the LT samples are stretched mainly by uniform strain without noticeable necking. Fracture analysis indicates that being different from typical cup-and-cone fracture surface in the RT samples, the 'radial' fracture surface appears in the LT samples. Such specific fracture surface is constructed by two characteristic morphologies of crack-initiation zone at sample surface and the ensuing crack-propagation zone. Furthermore, it is seen that a large number of micro-voids are dispersed underneath fracture surface in the RT samples, whereas the number of micro-voids is sharply reduced at LT. Nevertheless, Vickers hardness at the position is always much higher in the LT samples. These novel mechanical properties and damage-fracture characteristics in the LT samples are closely associated with the prevalent deformation twinning in microstructure. Deformation twinning itself and plentiful twins-induced dynamic Hall-Petch effect steadily accommodate plastic deformation, contributing to the simultaneous enhancement of strength and ductility. This process also results in high stress state in samples, increasing the sensitivity of surface cracking. Hence, the 'radial' fracture morphology is finally formed. These findings enrich our fundamental understanding on deformation-damage-fracture process of α-titanium alloys, and also provide implicit guidance for the design of titanium alloys with high performance. • Ti-2.5Cu alloy achieves superior tensile strength and ductility synergy at LT. • 'Radial' rather than cup-and-cone fracture surface appears in the LT samples. • Few micro-voids but higher hardness are displayed underneath fracture surface. • Twinning and plentiful twins steadily accommodate strain without localization. • Cracking sensitivity at sample surface caused by high stress makes radial fracture. [ABSTRACT FROM AUTHOR]

Photoelectrochemical sensing is a promising solution for health monitoring and food safety guarantee, and developing novel strategies for the facile preparation of advanced photoelectrochemical sensors is challenging. In this work, we report a novel strategy for preparing TiO 2 nanofibers threaded ZnO heterostructures and the selective photoelectrochemical detection of lactic acid. Cascade electrospinning and hot-pressing technologies were employed to prepare TiO 2 nanofibers threaded ZIF-8 precursor, and subsequent pyrolysis of ZIF-8 nanocrystals afforded beads-on-a-string heterostructures of TiO 2 @ZnO. The bead-like TiO 2 @ZnO heterostructures exhibit significantly enhanced charge transfer activity, photocurrent density and the smallest overpotential compared against that of ZnO and TiO 2. The resultant photoelectrochemical sensors demonstrate a low detection limit of 0.031 μM, a high sensitivity of 29.18 μA mM−1, a wide linear range between 0.1 and 1.0 mM, and excellent reproducibility. Furthermore, GC-MS and in situ FTIR studies confirm the mechanistic pathway of photoelectrochemical oxidation. This work provides a facile strategy for developing MOFs derived heterostructures, and advances in various high performance photoelectrochemical applications could be envisioned. [Display omitted] • Beads-on-a-string heterostructures of 1D TiO2@ZnO were fabricated. • Facile strategy of cascade hot-pressing ZIF-8 onto electrospun TiO2 was designed. • PEC detection of lactic acid was achieved with excellent selectivity and sensitivity. • Sensing mechanism was revealed by GC-MS and in situ DRIFTS studies. [ABSTRACT FROM AUTHOR]

As a kind of clean energy, magnesium batteries have become the main research direction of next-generation batteries. A long voltage lag time and irreversibility in aqueous electrolytes are problems faced by magnesium aqueous batteries. For the first time, we modified the anode of a magnesium aqueous battery with MXene. The modified battery not only reduced the voltage lag time of the battery but also improved the reversibility, cycle stability, and intermittent discharge performance of the magnesium aqueous battery. The calculation results of density functional theory showed that there is a high adsorption energy between MXene film and magnesium alloy. The calculation results of the ion diffusion energy barrier indicated that magnesium ions have a lower migration barrier on the surface of the MXene film layer. This research is of great significance to the development and application of magnesium batteries. • MXene coating was successfully prepared on the anode surface of magnesium battery. • The voltage lag time of the battery is reduced, and the formation of the anodic passive film is restrained. • It improves the discharge performance of magnesium battery in aqueous electrolyte and can light up LED light panel. • The modified battery has good stability and high ion migration rate. [ABSTRACT FROM AUTHOR]

In recycling process of spent lithium-ion batteries (LIBs), the Al impurities are generally existed in the obtained spent cathode active material, which undoubtedly affect the physical and electrochemical features of the recovered active materials. In this study, the effects of different forms (Al and Al3 +) and gradient concentrations (0.2, 0.5, and 1 at%) of Al impurity were investigated in the recovery of spent LiNi1/3Co1/3Mn1/3O2 (NCM111) cathode. The Al3 + impurity can promote the nucleation and growth of primary particles and reduce the cation mixing in the NCM111 cathode material, which benefits to the improvement of electrochemical performance. The obtained regenerated NCM material (R-NCMA) cathode displayed a great capacity of 183.75 mAh/g at 0.5 C and good cycling stability after 200 cycles (a capacity of 85.91% maintained). Meanwhile, the existing Al impurity can produce the more additional internal side reactions on the surface of the electrode and further affect the electrochemical performance. Based on these results, the existing form and concentration of Al impurities should be further considered and well controlled in the recycling of spent LIBs. • Electrochemical performance of direct repair materials using residual Al in spent cathode materials. • Al ions enhance the stability of the lamellar structure and inhibit phase changes and Li+ /Ni2 + mixing. • A moderate amount of Al ion impurities can be a beneficial dopant for regenerated NCM111 cathode materials. [ABSTRACT FROM AUTHOR]

Abstract Shock impedance matching between transparent ceramic windows and shock-loaded metal materials is the fundamental requirement for constructing a highly confident equation of state (EOS) for samples testing. The new Zn x Mg 1- x Al 2 O 4 spinel system has a wide range of shock impedance and a high pressure range transparency. In this paper, the shock impedance of Zn x Mg 1- x Al 2 O 4 spinel was designed by density functional theory (DFT). The results show that the Zn x Mg 1- x Al 2 O 4 system has good transparency in the test range of <18.5 Gpa, and the shock impedance of Zn x Mg 1- x Al 2 O 4 system matches well with that of Fe material in different pressure regions. This work provides a scientific reference for the selection of transparent window materials in the shock wave precision measurement of sample Fe. Highlights • A new transparent window material was found. • The shock impedance of Zn x Mg 1- x Al 2 O 4 was calculated for the first time. • The shock impedance of Zn x Mg 1- x Al 2 O 4 match that of Fe in a wide pressure region. • Zn x Mg 1- x Al 2 O 4 spinel has good transparency within 18.5 GPa. [ABSTRACT FROM AUTHOR]

Abstract Manipulation of the microstructural evolution to achieve controllable deformation and fracture behaviors in crystalline/amorphous nanolaminates is a grand challenge from the perspective of constraining effects of a crystalline on an amorphous phase. In this work, crystalline/amorphous Ag/Cu-Zr and Mo/Cu-Zr nanolaminates were respectively prepared by using magnetron sputtering. The microstructural evolution, tensile ductility, and fracture mode were investigated within a wide range of modulation ratio η (the thickness ratio of amorphous to crystalline layer) from 0.1 to 9.0. The Ag/Cu-Zr nanolaminates showed the tensile ductility firstly decreased and subsequently increased with raising η , leaving a minimum value at the critical η* of ∼1.0. The fracture mode was accordingly transformed from shearing to opening. However, the Mo/Cu-Zr nanolaminates exhibited a different η- dependence where the tensile ductility monotonically increased with η , with fracture mode unchanged as opening. The strong constituent effect on the deformation and fracture of crystalline/amorphous nanolaminates was rationalized in light of the deformation-induced devitrification behaviors in the amorphous layers, which was tuned by the constituent-dependent elastic modulus mismatch and the amorphous layer thickness. Furthermore, the devitrification behaviors were qualitatively interpreted in terms of the image force between constituents and the stress field of a dislocation. These findings manifest a microstructural design by controlled constituents to achieve enhanced mechanical properties in the crystalline/amorphous nanolaminates. Highlights • Controllable deformation-induced devitrification (DID) behaviors are investigated. • DID exhibits double-edged effects on the fracture behavior of amorphous layers. • DID and constraining contribute to the size-dependent tensile fracture behavior. [ABSTRACT FROM AUTHOR]

Mesoporous and magnetic nanomaterials have attracted great attention owing to their unique characteristics and promising applications in drug delivery. In this context, a novel method has been developed to engineer a nanostructure of unique walnut kernel-like SiO 2 /γ-Fe 2 O 3 nanocomposite by incorporating magnetic γ-Fe 2 O 3 crystallites into mesoporous SiO 2 nanospheres to exert their synergistic properties. The as-obtained SiO 2 /γ-Fe 2 O 3 nanospheres may be applied as a promising drug carrier due to suitable their advantages such as suitable particle size, mesoporous structure, large specific surface area, high biocompatibility, good loading capacity, and long efficiency time of the drug release behavior. In particular, the composite exhibits intense magnetic property, which may lead to the development of nanocomposite with great potential for applications in drug targeting and magnetic hyperthermia therapy. [ABSTRACT FROM AUTHOR]

The hot deformation and dynamic recrystallization behaviors of as-homogenized Mg–12Gd–4.5Y–2Zn–0.4Zr alloy were investigated through compression tests in this paper. This work presents the appropriate deformation zone. Different degrees of discontinuous dynamic recrystallization occurred in the alloys under different strain rates and temperatures. The critical strain prediction model of these alloys during hot deformation was obtained through calculation of work hardening rate θ , inflection points in the l n θ − ε curves and the minimum value of the − ( ∂ ( l n θ ) / ∂ ε ) - ε curves. At lower strain rates and temperatures, kink band deformations constitute an essential mechanism for homogeneous strain creation. As the strain rate increased, the kink band deformations became significantly serious, the new kinks were formed within the former kink bands, leading to grain refinement. In addition, a low amount of discontinuous dynamic recrystallizations occurred. As the strain rate increased, the volume fraction of discontinuous dynamic recrystallization was increased, whereas the kink band deformation decreased. [ABSTRACT FROM AUTHOR]

The electrodes with different morphological NiOOH layer on Nickel Foam (NF) have been prepared through a facile method. Firstly, the nickel chloride salt-urea-solvent (H 2 O、glycerol/H 2 O and ethylene glycol/H 2 O) systems were applied to adjust the morphology of Ni(OH) 2 on NF. The SEM results showed that the nanoplates and interspaces of deposited Ni(OH) 2 were regulated by adding organic solvent to influence the self-assembly process of Ni(OH) 2 . Further upon anodizing Ni(OH) 2 /NF samples, NiOOH/NF electrodes were obtained accordingly and utilized for the oxygen evolution reaction (OER). Based on electrochemical active surface area (EASA), the best activity toward OER was obtained on the electrode NiOOH/NF-30glycerol-8 with the current density of 0.20 mA/cm 2 @1.72 V vs. RHE. The evaluations of electrochemical active surface area for NiOOH/NF electrodes indicate that the increased active sites are attributed to the best OER efficiency on NiOOH/NF-30glycerol-8. [ABSTRACT FROM AUTHOR]

In theory, suitable metal ions doping into the surface of BiVO 4 photoanodes could improve its water oxidation performance effectively. But the common homogeneous reaction strategy is not well applicable for the preparation of BiVO 4 film photoanodes with metal ions surface doping. Herein, a photoelectrochemical treating approach was reported to prepare BiVO 4 films with W or Mo surface doping in saturated tungstate and molybdate-containing electrolyte, respectively. The doping of W or Mo into the surface of BiVO 4 film was attributed to the following reactions. Firstly, the photocorrosion of BiVO 4 film photoelectrodes resulted in the dissolution of VO 4 3+ from BiVO 4 lattice under AM 1.5 G illumination. Then, the WO 4 2+ or MoO 4 2+ in the saturated electrolyte entered and occupied the dissolved sites of VO 4 3+ on BiVO 4 surface through ions exchange reaction. Due to the lower radiative recombination of carrier as well as higher electrocatalytic water oxidation activity, the resultant W or Mo doped BiVO 4 films as photoanodes showed better solar water oxidation activity, kinetics and stability, although their light harvesting property and morphological feature were close to the pristine BiVO 4 film photoanode. The present work provides a new and effective approach for the achievement of metal ions doping into the surface of BiVO 4 photoanodes, which could inspire the preparation of similar photoanode materials. [Display omitted] • A photoelectrochemical treating approach was developed to prepare BiVO 4 films with W or Mo surface doping. • W or Mo was doped into BiVO 4 surface through the ions exchange of VO 4 3+ with WO 4 2+ or MoO 4 2+. • Better water oxidation activity, kinetics and stability were observed on the W or Mo doped BiVO 4 film photoanodes. [ABSTRACT FROM AUTHOR]

The nanostructured Ti/Ta and Ti/Zr multilayers with equal layer thicknesses h ranging from 2.5 to 150 nm were prepared by using magnetron sputtering technique. Their rate dependent deformation behaviors were explored by nanoindentation. With reducing h , the strain rate sensitivity m of Ti/Ta multilayers decreased from a positive value to negative at the critical h * of ~ 20 nm, at which the hardness is insensitive to strain rate. While the m of Ti/Zr multilayers decreased as the decreasing of h. This evolution of strain rate sensitivity in multilayers was interpreted in terms of the heterogeneously interfacial structure, i.e., the constituent interlayer coherent interfaces and phase boundaries in nanolayers. The deformation morphologies after nanoindentation were observed and discussed to further examine plastic deformation and dislocation activities of multilayers. • The formation of coherent interfaces decreases SRS of Ti/Ta and Ti/Zr multilayers. • The SRS platform is obtained in Ti/Ta due to the competition between coherent interfaces and incoherent phase boundaries. • Pile-ups deformation morphologies after nanoindentation which related with dislocation activities are observed. • The influences of interface structures and grain orientation on dislocations propagation were discussed. [ABSTRACT FROM AUTHOR]

The spherical La-Fe-Co-Si compound particles with giant magneto-caloric properties prepared by plasma rotating electrode process (PREP) and hydrogen permeation were obtained and their mechanism was investigated in this paper. Compared with the alloys prepared by the traditional melting and casting methods, the spherical particles prepared by the PREP have a uniform and refined structure and benefit to form the NaZn 13 -type phase with giant magneto-caloric effect (MCE). The magnetic properties of spherical particles with three different sizes show that the particles with size between 450 µm and 600 µm had the best magneto-caloric properties, the isothermal magnetic entropy change can reach 12.67 J·kg−1·K−1, corresponding to the applied magnetic field changes of 0 −1.5 T. Hydrogen permeation can increase the Curie temperature (T c) of spherical particles, which can be ascribed to the magneto-volume effect caused by change in cell volume. When the hydrogen permeation pressure is 100 Pa, the T c increases from 218 K to 224 K, and the structure of the spherical particles remains stable at this time. The spherical La-Fe-Co-Si compound particles with giant MCE and excellent heat exchange ability are promising materials for commercial applications of magnetic refrigeration technology. • The spherical LaFe 11.3 Co 0.2 Si 1.5 alloy prepared by the plasma rotating electrode process has a uniform and fine structure. • The spherical particles can completely form NaZn 13 -type phase after heat treatment at 1373K for 120h. • Adjusting the appropriate hydrogen permeation pressure can keep the structure stable and increase the Curie temperature. [ABSTRACT FROM AUTHOR]

Creep behaviors of nanocrystalline (NC) Cu, Ni-20(wt.%)Fe and Ni with comparable grain sizes were examined by nanoindentation tests. It was showed that the creep behaviors depend on loading strain rate and stacking fault energy (SFE). At high loading strain rate, the initial creep rates of three NC materials are far higher than those predicted by the models of the Coble creep and the grain boundary sliding and are the highest and lowest for NC Cu and NC Ni, respectively, while that of NC Ni–20Fe lies between them due to their different SFE. At low loading strain rate, the creep behaviors do not exhibit significant difference among three NC materials. Our analysis revealed that grain boundary dislocation sources can be activated at high loading strain rate and the emitted dislocations from grain boundaries can be effectively stored in the loading regime, but cannot at low loading strain rate. The very high initial creep rates of three NC materials are attributed to the rapid absorptions of the stored dislocations in the loading regime and the newly nucleated dislocations in the holding regime. The higher creep rate of NC Cu as compared with those of NC Ni–20Fe and NC Ni arises from the higher density of the stored dislocations caused by the enhanced interactions of dislocations with twins and stacking faults due to its lower SFE. [ABSTRACT FROM AUTHOR]

• Heterogeneous interfaces in Ni/FeMnCoNi nanolaminates transform from incoherent to coherent at layer thickness below 25 nm. • Both constituent layers of Ni/FeMnCoNi nanolaminates co-deform during plastic deformation. • Strengthening mechanisms are revealed to be the confined slip of dislocation within constituent layers and columnar grains. Introducing heterogeneous interfaces by constructing laminated structure is a promising avenue to achieve the controllable strengthening behavior of high entropy alloys. In this work, the microstructural evolution and mechanical properties of magnetron sputtered Ni/Fe 50 Mn 30 Co 10 Ni 10 nanolaminates with equal layer thickness h ranging from 5 to 150 nm were investigated systematically. With reducing h , the nanoindentation hardness of Ni/FeMnCoNi nanolaminates firstly increased and subsequently decreased, emerging a maximum value at the critical h of ~25 nm due to the transformation of constraining barrier for dislocation slipping from the heterogeneous interfaces to columnar grain boundaries. Microstructural observation demonstrated that the interfacial structure of Ni/FeMnCoNi transformed from incoherent to completely coherent at h below ~25 nm, and both the constituent layers made comparable contribution to the plastic deformation of Ni/FeMnCoNi nanolaminates. The strong h -dependent mechanical behavior could be rationalized in terms of the co-deformation of constituent layers and the structural evolution of Ni/FeMnCoNi interface. Additionally, the strengthening mechanisms were discussed based on the confined slip of dislocation within the constituent layers and columnar grains. [ABSTRACT FROM AUTHOR]

In this study, an Al-5.5Zn-2.2Mg-1.2Cu-0.12Zr (wt%) alloy with a high dislocation density was successfully fabricated by twin-roll casting (TRC). The effects of two-stage homogenization processes on the precipitation behavior of the L1 2 -structured Al 3 Zr phase and recrystallization in this Al-Zn-Mg-Cu-Zr alloy were investigated. Furthermore, the influences of the Al 3 Zr and recrystallization levels on the mechanical properties and intergranular corrosion (IGC) resistance were evaluated. Based on the obtained results, compared to conventional single-stage homogenization, the two-stage homogenization significantly enhanced the precipitation of Al 3 Zr due to the higher driving force and greater number of heterogeneous nucleation sites provided for the precipitation in the first stage. Therefore, the number density and volume fraction of Al 3 Zr increased significantly. Additionally, the holding times at the different stages affected the precipitation of Al 3 Zr. As the first-stage time increased, the number density and volume fraction of Al 3 Zr increased and then decreased, which was caused by the evolution of heterogeneous nucleation sites (T phase). As the second-stage time increased, the nucleation, growth, and Ostwald ripening of Al 3 Zr occurred. Variations of the f v / r ratio of the Al 3 Zr phase led to different recrystallization resistances during the solution treatment. Therefore, partially recrystallized microstructures were achieved in the two-stage homogenized alloys after the T6 treatments. These microstructures and the corresponding distributions of Al 3 Zr slightly affected the mechanical properties, while they significantly improved the IGC resistance. • L1 2 Al 3 Zr precipitation behavior under various two-stage homogenization processes. • Heterogeneous nucleation sites (T phase) and high Zr supersaturation enhance Al 3 Zr precipitation. • High f V / r ratio of Al 3 Zr in two-stage homogenized alloys effectively inhibits recrystallization. • Inhibiting recrystallization improves mechanical properties and IGC resistance, especially for the latter. [ABSTRACT FROM AUTHOR]

• Deformation kinking is found in Ti-V metastable β -Ti alloys for the first time. • Kink bands co-appear with slip bands in the deformed β -grains. • Deformation-induced ω -precipitates are produced in kink bands due to local strain. • Kink bands are suggested to follow a dislocation-based formation mechanism. [Display omitted] Unlike stress-induced martensitic transformation, deformation twinning as well as dislocation gliding, deformation kinking is an uncommon deformation mechanism in metastable β -titanium (Ti) alloys. In this study, the unique deformation mechanism was reported in Ti-V binary β -Ti alloys for the first time. It was found that a large number of kink bands were distributed in β -grains after cold forging at a strain rate of ~103 s−1. Microstructural characterization manifests that the appearance of kink bands is frequently accompanied by slip bands, whilst dense dislocations are accumulated around the kink bands on a microscopic scale. Such local plastic deformation is quite strong so that the pre-existing athermal ω -precipitates in the initial microstructure is completely destroyed within the kink bands and instead fresh deformation-induced single variant of ω -precipitates is produced. This deformation localization mainly originates from the impediment of dislocation activity caused by both pre-existing athermal ω -precipitates and the intrinsic slip retardation in BCC crystal structures. The deformation kinking is thus suggested to follow a dislocation-based formation mechanism, whilst the resulting Taylor axis of lattice rotation was deduced to be<011> β on basis of extensive crystallographic analysis. These findings enrich fundamental understanding on deformation kinking, and provide helpful information for utilizing the unique deformation mechanism to tune mechanical properties of β -Ti alloys. [ABSTRACT FROM AUTHOR]

• A simple electrostatic attraction method synthesis Z-Scheme ternary heterojunction. • Formed Schottky junction make electrons and holes can be maximal separation. • Optimized degradation performance on MB and TC under visible-light irradiation. • Discussed the path of charge transfer and the mechanism of pollutant degradation. ga1 The discharge of industrial wastewater poses serious concerns to the environment and human health. Therefore, urgent development of simple and efficient catalysts for removal of pollutants is required. In this study, a novel ternary nanocomposite Ag/g-C 3 N 4 /LaFeO 3 (A/CN/LFO) was synthesized for the degradation of dye and pharmaceutical wastewater. The catalyst was prepared by decorating Ag nanoparticles (NPs) on g-C 3 N 4 /LaFeO 3 (CN/LFO) Z-scheme heterojunction and formation of Schottky junctions with LaFeO 3 (LFO) and g-C 3 N 4 (CN). The formed hybrid structure between metal and Z-scheme heterojunction induced directional transfer of electrons or holes from the Z-scheme heterojunction to metal, providing maximum separation between electrons and holes for more efficient redox reactions. Consequently, the ternary nanocomposite displayed optimized efficiencies toward the photocatalytic degradation of methylene blue (MB) and tetracycline hydrochloride (TC) under visible-light irradiation, estimated to 98.97% (90 min) and 94.93% (120 min), respectively. These values were almost 4.81 times and 3.88 times higher than those of pristine LaFeO 3 , respectively. The charge transfer mechanism and pollutant degradation pathway were also studied. The data revealed that Ag decorated Z-scheme heterojunction showed efficient light absorption and separation of photogenerated carriers, which might be useful for large-scale practical applications related to wastewater treatment and pollution control. [ABSTRACT FROM AUTHOR]

High emissivity coating is an important part of spacecraft thermal protection system. MoSi 2 -borosilicate glass coatings prepared by the in-situ reaction method showed excellent thermal endurance and oxidation resistance. However, radial cracks were prone to appear under external forces due to high cohesive of in-situ reaction dense coatings, and few studies focused on the mechanical properties of gradient coatings. In this study, a double-layer gradient MoSi 2 -borosilicate glass coating with a porous interface layer and a dense surface layer was prepared on mullite fibrous insulation tiles by in-situ reaction method. The double-layer gradient coating was compared with a mono-layer dense coating and a high-density gradient coating (another gradient coating with higher interface layer density) with reference to microstructure, contact damage resistance, interface bonding strength and thermal shock resistance. Compared with mono-layer dense coating and high-density gradient coating, double-layer gradient coating showed higher bearing capacity and avoided radial crack initiation and propagation in Hertzian indentation test. Besides, the double-layer gradient coating endured the most thermal shock cycles between 1500 °C and 20 °C and presented substrate fracture instead of interface fracture. In addition, double-layer gradient coating and high-density gradient coating possessed much higher interface bonding strengths than mono-layer dense coating. The total emissivities of three coatings were all greater than 0.87. The porous interface in double-layer gradient coating presented the advantages in enhanced mechanical and thermal compatibility between the in-situ reaction dense coating and substrate through reducing elastic modulus and thermal expansion coefficient differences. • A double-layer gradient coating with excellent mechanical properties was prepared. • Failure mode and fracture mechanism of coatings were related to interface stress. • Gradient interface reduced modulus and CTE difference between coating and substrate. • Low density thick gradient interface was conducive to release interface stress. [ABSTRACT FROM AUTHOR]