FeSiAl-based soft magnetic composites(SMCs),prepared from insulated FeSiAl powders,are widely applied in electronic devices.However,it is still challenging to achieve high magnetic and mechanical properties simultaneo...FeSiAl-based soft magnetic composites(SMCs),prepared from insulated FeSiAl powders,are widely applied in electronic devices.However,it is still challenging to achieve high magnetic and mechanical properties simultaneously due to the undesirable insulation layer.Here,double Al_(2)O_(3) insulation layers are prepared for FeSiAl SMC.Atomic-scale characterizations reveal an in-situ epitaxial Al_(2)O_(3) layer at FeSiAl surface under the catalysis of NaAlO_(2),and an outer amorphous Al_(2)O_(3) layer by subsequent NaAlO2 hydrolysis.The above structure ensures effective insulation of FeSiAl powders and excellent magnetic properties of the FeSiAl/NaAlO2 SMC,with permeability of 101 and power loss of 128 mW/cm^(3)(50 mT,100 kHz)respectively.Moreover,in-situ Al_(2)O_(3)/amorphous Al_(2)O_(3) on FeSiAl matrix also leads to distinguished crush strength of 36.5 MPa for the core sample,which is ascribed to the enhanced adhesion at different interfaces as evidenced by similar local oxygen coordination and low strain distribution.This work provides a novel method to fabricate high-performance FeSiAl SMCs.展开更多
To improve the compactness and properties of C/C-SiC-ZrC composites produced by precursor infiltration and pyrolysis(PIP)method,the low-temperature reactive melt infiltration(RMI)process was used to seal the composite...To improve the compactness and properties of C/C-SiC-ZrC composites produced by precursor infiltration and pyrolysis(PIP)method,the low-temperature reactive melt infiltration(RMI)process was used to seal the composites using Zr_(2)Cu as the filler.The microstructure,mechanical properties,and ablation properties of the Zr_(2)Cu packed composites were analyzed.Results show that during Zr_(2)Cu impregnation,the melt efficiently fills the large pores of the composites and is converted to ZrCu due to a partial reaction of zirconium with carbon.This results in an increase in composite density from 1.91 g/cm^(3)to 2.24 g/cm^(3)and a reduction in open porosity by 27.35%.Additionally,the flexural strength of Zr_(2)Cu packed C/C-SiC-ZrC composites is improved from 122.78±8.09 MPa to 135.53±5.40 MPa.After plasma ablation for 20 s,the modified composites demonstrate superior ablative resistance compared to PIP C/C-SiC-ZrC,with mass ablation and linear ablation rates of 2.77×10^(−3)g/s and 2.60×10^(−3)mm/s,respectively.The“selftranspiration”effect of the low-melting point copper-containing phase absorbs the heat of the plasma flame,further reducing the ablation temperature and promoting the formation of refined ZrO_(2)particles within the SiO_(2)melting layer.This provides more stable erosion protection for Zr_(2)Cu packed C/C-SiC-ZrC composites.展开更多
The advancement of planar micro-supercapacitors(PMSCs)for micro-electromechanical systems(MEMS)has been significantly hindered by the challenge of achieving high energy and power densities.This study addresses this is...The advancement of planar micro-supercapacitors(PMSCs)for micro-electromechanical systems(MEMS)has been significantly hindered by the challenge of achieving high energy and power densities.This study addresses this issue by leveraging screen-printing technology to fabricate high-performance PMSCs using innovative composite ink.The ink,a synergistic blend of few-layer graphene(Gt),carbon black(CB),and NiCo_(2)O_(4),was meticulously mixed to form a conductive and robust coating that enhanced the capacitive performance of the PMSCs.The optimized ink formulation and printing process result in a micro-supercapacitor with an exceptional areal capacitance of 18.95 mF/cm^(2)and an areal energy density of 2.63μW·h/cm^(2)at a current density of 0.05 mA/cm^(2),along with an areal power density of 0.025 mW/cm^(2).The devices demonstrated impressive durability with a capacitance retention rate of 94.7%after a stringent 20000-cycle test,demonstrating their potential for long-term applications.Moreover,the PMSCs displayed excellent mechanical flexibility,with a capacitance decrease of only 3.43%after 5000 bending cycles,highlighting their suitability for flexible electronic devices.The ease of integrating these PMSCs into series and parallel configurations for customized power further underscores their practicality for integrated power supply solutions in various technologies.展开更多
Compared with Cu/Al_(2)O_(3)composites,high-strength Cu/Al_(2)O_(3)composites usually exhibit obviously deteriorated electrical conductivity.A chemical and mechanical alloying-based strategy was adopted to fabricate u...Compared with Cu/Al_(2)O_(3)composites,high-strength Cu/Al_(2)O_(3)composites usually exhibit obviously deteriorated electrical conductivity.A chemical and mechanical alloying-based strategy was adopted to fabricate ultrafine composite powders with lowcontent reinforcement and constructed a combined structure of Cu ultrafine powders covered with in-situ Al_(2)O_(3)nanoparticles.After consolidation at a relatively lower sintering temperature of 550℃,high-volume-fraction ultrafine grains were introduced into the Cu/Al_(2)O_(3)composite,and many in-situ Al_(2)O_(3)nanoparticles with an average size of 11.7±7.5 nm were dispersed homogeneously in the Cu grain.Results show that the composite demonstrates an excellent balance of high tensile strength(654±1 MPa)and high electrical conductivity(84.5±0.1%IACS),which is ascribed to the synergistic strengthening effect of ultrafine grains,dislocations,and in-situ Al_(2)O_(3)nanoparticles.This approach,which utilizes ultrafine composite powder with low-content reinforcement as a precursor and employs low-temperature and high-pressure sintering subsequently,may hold promising potential for large-scale industrial production of high-performance oxide dispersion strengthened alloys.展开更多
Photocatalysis is an important process in energy conversion and environmental usage because of its feasible,profitable,and environmentally safe benefits.Coordination chemistry of the CeO_(2)is gaining significant inte...Photocatalysis is an important process in energy conversion and environmental usage because of its feasible,profitable,and environmentally safe benefits.Coordination chemistry of the CeO_(2)is gaining significant interest because its nanocomposites show unique characteristics namely optically active,wide bandgap(Eg),reversible valence states(Ce^(3+/4+)),rich defect architectures,high O_(2)storage capability,ionic conductivity,and exceptional chemical resistance.Systematically summarized the importance of synthesis methods,particle morphology,and crystal structure aiming at how to heighten the efficacy of CeO_(2)-derived hybrid heterojunction(HHJ)photocatalyst.Selection of an appropriate synthesis method and morphology of the composite materials are beneficial in inhibiting the rapid electron-hole(e^(−)-h^(+))recombination,improvement in visible light adsorption,and large generation of e^(−)-h^(+)pairs to accelerate the photocatalysts activities.Various modification approaches include elemental doping(metal/non-metal doping),heterojunction construction(lower/wide Eg semiconductors(SCD),carbon,conducting polymeric materials),imperfection engineering,and multicomponent hybrid composites.These methods assist as a valuable resource for the rational design of effective CeO_(2)-based composite photocatalysts for sustainable development owing to the enhancement of oxygen species mobility,rapid charge transfer,maximum visible light captivation and slow down the charge recombination rate with increase photogeneration of e−-h+pairs.Also examines the advancements made in CeO_(2)conjugated hybrid composites in photo-oxidation of wastewater effluents(antibiotic/organic dyes/chemical/pharmaceutical),heavy metal removal,H2 production,CO_(2)reduction,and H2O splitting applications.Subsequently,the difficulties and fundamental ideas behind several heterojunction photocatalysts encountered by CeO_(2)-based composites are examined,and future directions for their development are suggested.展开更多
Unmanaged wood waste,particularly in countries like Nepal,presents serious environmental concerns due to open burning and improper disposal,leading to carbon emissions,air pollution and land degradation.This study int...Unmanaged wood waste,particularly in countries like Nepal,presents serious environmental concerns due to open burning and improper disposal,leading to carbon emissions,air pollution and land degradation.This study introduces an environmentally sustainable strategy to upcycle Toona ciliata wood scrap—an abundant and underutilized lignocellulosic biomass—into high performance carbon electrodes for green energy storage applications.Activated carbon(TCWAC)was synthesized via single-step pyrolytic carbonization followed by phosphoric acid activation,yielding a material with high specific surface area,hierarchical porosity,and excellent electrical conductivity.Electrochemical measurements using a three-electrode configuration in 6 M KOH revealed optimized potential windows of -1.0 to -0.2 V(TCWAC),-1.2 to 0 V(TCWAC-Mn),and -1.15 to -0.4 V(TCWAC-Fe).TCWAC exhibited a specific capacitance of 156.3 Fg^(-1)at 1 Ag^(-1),with an energy density of 3.5 Whkg^(-1),and 80.2% capacity retention after 1000 charge-discharge cycles.Composites with MnO_(2)and Fe_(2)O_(3)were also evaluated.TWAC-Mn delivered 489.4 Fg^(-1),25.1 Whkg^(-1),and 99.1% retention,whereas,TWAC-Fe achieved 321.3 Fg^(-1),6.3 Whkg^(-1),and 90.3% retention.The superior performance of MnO_(2)is attributed to its multiple oxidation states,facilitating reversible faradaic redox and enhanced pseudocapacitance.This work offers the first direct,systematic comparison of MnO_(2)and Fe_(2)O_(3)composites on a common biomass-carbon matrix under identical synthesis and testing conditions.The finding provides mechanistic insight into charge storage behaviour and demonstrate a scalable route for converting biomass waste into sustainable electrode materials,contributing to cleaner energy solutions and improved biomass valorization.展开更多
We synthesized tungsten-doped vanadium dioxide(W-VO_(2))particles via a one-step hydrothermal method,followed by their integration with antimony-doped tin oxide(ATO)nanoparticles to formulate a composite coating.Subse...We synthesized tungsten-doped vanadium dioxide(W-VO_(2))particles via a one-step hydrothermal method,followed by their integration with antimony-doped tin oxide(ATO)nanoparticles to formulate a composite coating.Subsequently,the VO_(2)/ATO composite coating was fabricated through a spin-coating process.The impact of varying W-VO_(2) content and coating thickness on the performance of the composite coatings was systematically investigated by employing X-ray diffraction,particle size distribution analysis,spectrometry,and other pertinent test methodologies.Our findings revealed that an escalation in both W-VO_(2) content and coating thickness retained high transmittance in the near-infrared band at lower temperatures.However,as the temperature increased,a notable reduction in transmittance in the near-infrared band was observed,alongside a slight decrease in transmittance within the visible band.Remarkably,when the W-VO_(2) content reached 5%and the coating thickness was 1253 nm,the transmittance of the composite coating surpassed 80%.Furthermore,the heat insulation effect achieved a remarkable 10.0℃increase.Consequently,the synthesized composite coating demonstrates significant potential for smart glass applications,particularly in the realm of heat-insulating glass.展开更多
BACKGROUND Due to saliva and salivary glands are reservoir to severe acute respiratory syndrome-coronavirus 2(SARS-CoV-2),aerosols and saliva droplets are primary sources of cross-infection and are responsible for the...BACKGROUND Due to saliva and salivary glands are reservoir to severe acute respiratory syndrome-coronavirus 2(SARS-CoV-2),aerosols and saliva droplets are primary sources of cross-infection and are responsible for the high human–human transmission of SARS-CoV-2.However,there is no evidence about how SARSCoV-2 interacts with oral structures,particularly resin composites.AIM To evaluate the interaction of SARS-CoV-2 proteins with monomers present in resin composites using in silico analysis.METHODS Four SARS-CoV-2 proteins[i.e.main protease,3C-like protease,papain-like protease(PLpro),and glycoprotein spike]were selected along with salivary amylase as the positive control,and their binding affinity with bisphenol-A glycol dimethacrylate,bisphenol-A ethoxylated dimethacrylate,triethylene glycol dimethacrylate,and urethane dimethacrylate was evaluated.Molecular docking was performed using AutoDock Vina and visualised in Chimera UCSF 1.14.The best ligand–protein model was identified based on the binding energy(ΔG–kcal/moL).RESULTS Values for the binding energies ranged from-3.6 kcal/moL to-7.3 kcal/moL.The 3-monomer chain had the lowest binding energy(i.e.highest affinity)to PLpro and the glycoprotein spike.Non-polymerised monomers and polymerised chains interacted with SARS-CoV-2 proteins via hydrogen bonds and hydrophobic interactions.Those findings suggest an interaction between SARS-CoV-2 proteins and resin composites.CONCLUSION SARS-CoV-2 proteins show affinity to non-polymerised and polymerised resin composite chains.展开更多
B2-CuZr phase reinforced amorphous alloy matrix composites has become one of the research hotspots in the field of materials science due to the“transformation-induced plasticity”phenomenon,which makes the composites...B2-CuZr phase reinforced amorphous alloy matrix composites has become one of the research hotspots in the field of materials science due to the“transformation-induced plasticity”phenomenon,which makes the composites show better macroscopic plastic deformability and obvious work-hardening behavior compared to the conventional amorphous alloy matrix composites reinforced with ductile phases.However,the in-situ metastable B2-CuZr phase tends to undergo eutectoid decomposition during solidification,and the volume fraction,size,and distribution of B2-CuZr phase are difficult to control,which limits the development and application of these materials.To date,much efforts have been made to solve the above problems through composition optimization,casting parameter tailoring,and post-processing technique.In this study,a review was given based on relevant studies,focusing on the predictive approach,reinforcing mechanism,and microstructure tailoring methods of B2-CuZr phase reinforced amorphous alloy matrix composites.The research focus and future prospects were also given for the future development of the present composite system.展开更多
The Al-Mg_(2)Si in-situ composite is a lightweight material with great potential for application in fields such as automotive lightweighting,aerospace,and electronic components.In this research,the modification,semi-s...The Al-Mg_(2)Si in-situ composite is a lightweight material with great potential for application in fields such as automotive lightweighting,aerospace,and electronic components.In this research,the modification,semi-solid technology coupled with different types of electromagnetic stirring was applied to regulate the undesirable solidified dendritic microstructure and facilitate the composites’mechanical properties.The spheroidization and refinement of Mg_(2)Si andα-Al matrix in SM(semi-solid)+RES(rotate electromagnetic stirring)sample and SM+SHES(single winding helical electromagnetic stirring)sample are realized under the effect of fused dendrite arm,the decreased critical nucleate radius,and the increased nucleation rate and extra supercooling degree induced by electromagnetic stirring.The Mg_(2)Si phase in the SM+RES sample and SM+SHES sample is refined by 73.4%and 75.7%,respectively compared to the AC(as-cast)sample.Besides,the single winding electromagnetic stirring can lead to more homogeneously distributed physical fields,lower temperature gradient,and more significant mass transfer,mainly responsible for the more homogeneous distributed reinforced finer Mg_(2)Si particles in the SM+SHES sample.Moreover,both the tensile properties and hardness of modified semi-solid composites are improved through electromagnetic stirring.Compared with RES,the improvement effect of SHES is more excellent.The SM+SHES sample possesses the highest Brinell hardness(124.7 HB),and its quality index of tensile properties is 5.73%and 82.2%higher than that of the SM+RES and AC samples,respectively.展开更多
Ultrasonic vibration treatment(UVT)at varying power was successfully applied to the Cu–TiB_(2) composite melt using a SiAlON ceramic sonotrode.The results indicate that TiB_(2) particles are more evenly dispersed in ...Ultrasonic vibration treatment(UVT)at varying power was successfully applied to the Cu–TiB_(2) composite melt using a SiAlON ceramic sonotrode.The results indicate that TiB_(2) particles are more evenly dispersed in the Cu matrix with increasing ultrasonic power,leading to improved mechanical properties of as-cast composites(≤1000 W).With 1000 W UVT,the distribution of TiB_(2) particles becomes the remarkably uniform and well dispersed,with the size of TiB_(2) particle aggregates decreasing from~50μm without UVT to~5μm.The ultimate tensile strength,yield strength,and elongation of the as-cast composite are 201 MPa,85 MPa,and 28.6%,respectively,representing increases of 21.1%,27.3%,and 43%,respectively,compared to the as-cast composite without UVT.However,when the power is increased to 1500 W,thermal efects are likely to emerge,and the ultrasonic attenuation efect is enhanced,resulting in the re-agglomeration of TiB_(2) particles and a deterioration in performance.By quantitatively analyzing the relationships between sound pressure(Pk),sound energy density(I),sound pulse velocity(V),and ultrasonic power,the infuence mechanism of ultrasonic power on the composite microstructure has been further elucidated and characterized.This study provides crucial guidance for the industrial application of UVT in the fabrication of Cu matrix composites.展开更多
A novel mechanical stirring-assisted double-melt in-situ reaction casting process was developed to prepare Cu-1TiB2(wt%)composites.The effects of preparation parameters(melting reaction temperature,stirring rate and s...A novel mechanical stirring-assisted double-melt in-situ reaction casting process was developed to prepare Cu-1TiB2(wt%)composites.The effects of preparation parameters(melting reaction temperature,stirring rate and stirring time)on the microstructure and properties of Cu-1TiB2 composites were investigated.The melt viscosity and particle motion during stirring process were analyzed.The strong turbulence and shear effects generated by mechanical stirring in the melt not only significantly improve the particle distribution but also contribute to adequate in-situ reactions and precise control of the chemical composition.The optimal preparation parameters were 1200℃,a stirring rate of 100 r·min^(−1) and a stirring time of 1 min.Combined with the cold rolling process,the tensile strength,elongation and electrical conductivity of the composite reached 475 MPa,6.0%and 88.4%IACS,respectively,which were significantly better than the composite prepared by manual stirring.The good plasticity is attributed to the uniform distribution of TiB_(2) particles,effectively retarding the crack propagation.The dispersion of particles promotes heterogeneous nucleation of Cu matrix and inhibits grain growth.On the other hand,dispersed particles contribute to grain shear fracture and dislocation multiplication during cold deformation.Therefore,the composite achieves higher dislocation strengthening and grain boundary strengthening.展开更多
Cost-effective CO_(2) adsorbents are gaining increasing attention as viable solutions for mitigating climate change.In this study,composites were synthesized by electrochemically combining the post-gasification residu...Cost-effective CO_(2) adsorbents are gaining increasing attention as viable solutions for mitigating climate change.In this study,composites were synthesized by electrochemically combining the post-gasification residue of Macadamia nut shell with copper benzene-1,3,5-tricarboxylate(CuBTC).Among the different composites synthesized,the ratio of 1:1 between biochar and CuBTC(B 1:1)demonstrated the highest CO_(2) adsorption capacity.Under controlled laboratory conditions(0℃,1 bar,without the influence of ambient moisture or CO_(2) diffusion limitations),B 1:1 achieved a CO_(2) adsorption capacity of 9.8 mmol/g,while under industrial-like conditions(25℃,1 bar,taking into account the impact of ambient moisture and CO_(2) diffusion limitations within a bed of adsorbent),it reached 6.2 mmol/g.These values surpassed those reported for various advanced CO_(2) adsorbents investigated in previous studies.The superior performance of the B 1:1 composite can be attributed to the optimization of the number of active sites,porosity,and the preservation of the full physical and chemical surface properties of both parentmaterials.Furthermore,the composite exhibited a notable CO_(2)/N_(2) selectivity and improved stability under moisture conditions.These favorable characteristics make B 1:1 a promising candidate for industrial applications.展开更多
In this study,a NbB_(2)/AZ91 composite exhibiting desirable mechanical properties was fabricated using a sample casting technique,followed by hard-plate rolling and short-term annealing.The effect of NbB_(2)particles ...In this study,a NbB_(2)/AZ91 composite exhibiting desirable mechanical properties was fabricated using a sample casting technique,followed by hard-plate rolling and short-term annealing.The effect of NbB_(2)particles on the microstructural evolution of the AZ91 alloy was investigated.The presence of NbB_(2)was shown to have a grain-refining effect on the AZ91 alloy and promoted dynamic recrystallization(DRX)and precipitation of fine Mg_(17)Al_(12)phases via particle-stimulated nucleation(PSN).Tensile testing revealed substantial enhancements in the ultimate tensile strength(UTS),yield strength(YS),and elongation(EL)of the as-rolled AZ91 alloy,with values of 379 MPa,292 MPa,and 14.7%,respectively,owing to the incorporation of NbB_(2)particles.Annealing led to further enhancements in EL with slight reductions in UTS and YS(360 MPa,252 MPa,and 16.8%,respectively).Owing to grain refinement and the PSN effect of the NbB_(2)particles,a significant number of geometrically necessary dislocations(GNDs)were induced in the matrix during the rolling process,which reduces the nucleation barrier and increases the number of nucleation sites for the recrystallized grains and Mg_(17)Al_(12)precipitates.Meanwhile,many residual dislocations and fine Mg_(17)Al_(12)precipitates in the as-rolled alloys were annihilated during annealing,resulting in slight grain growth and coarsening.The strengthening mechanism of the NbB_(2)/AZ91 composite are mainly associated with grain-refinement strengthening,particle-induced dislocation strengthening,strengthening resulting from mismatching coefficients of thermal expansion(CTE),and heterodeformation-induced(HDI)strengthening.Textural weakening,increased activation of non-basal slip systems,more-uniform strain patterns resulting from NbB_(2)particles,and precipitation are mainly responsible for enhancing ductility.展开更多
Mg alloys have the defects of low stiffness,low strength,and high coefficient of thermal expansion(CTE).The composites strategy and its architecture design are effective approaches to improve the comprehensive perform...Mg alloys have the defects of low stiffness,low strength,and high coefficient of thermal expansion(CTE).The composites strategy and its architecture design are effective approaches to improve the comprehensive performance of materials,but the processing difficulty,especially in ceramics forming,limits the control and innovation of material architecture.Here,combined with 3D printing and squeeze infiltration technology,two precisely controllable architectures of AZ91/Al_(2)O_(3)interpenetrating phase composites(IPC)with ceramic scaffold were prepared.The interface,properties and impact of different architecture on IPC performance were studied by experiments and finite element simulation.The metallurgical bonding of the interface was realized with the formation of MgAl_(2)O_(4)reaction layer.The IPC with 1 mm circular hole scaffold(1C-IPC)exhibited significantly improved elastic modulus of 164 GPa,high compressive strength of 680 MPa,and good CTE of 12.91×10^(-6)K^(−1),which were 3.64 times,1.98 times and 55%of the Mg matrix,respectively.Their elastic modulus,compressive strength,and CTE were superior to the vast majority of Mg alloys and Mg based composites.The reinforcement and matrix were bicontinuous and interpenetrating each other,which played a critical role in ensuring the potent strengthening effect of the Al_(2)O_(3)reinforcement by efficient load transfer.Under the same volume fraction of reinforcements,compared to IPC with 1 mm hexagonal hole scaffold(1H-IPC),the elastic modulus and compressive strength of 1C-IPC increased by 15%and 28%,respectively,which was due to the reduced stress concentration and more uniform stress distribution of 1C-IPC.It shows great potential of architecture design in improving the performance of composites.This study provides architectural design strategy and feasible preparation method for the development of high performance materials.展开更多
An Al_(2)O_(3)/Al-Cu-Mn composite was fabricated using a combination of ball milling and liquid-solid reaction,with a nominal composition of Al-4Cu-0.5Mn-2.8γ-Al_(2)O_(3).The composite contains reinforcement particle...An Al_(2)O_(3)/Al-Cu-Mn composite was fabricated using a combination of ball milling and liquid-solid reaction,with a nominal composition of Al-4Cu-0.5Mn-2.8γ-Al_(2)O_(3).The composite contains reinforcement particles,including nano-sizedθ’and T(Al_(20)Cu_(2)Mn_(3))particles after T6 heat treatment,as well as in-situ synthesized nano-sizedγ-Al_(2)O_(3)particles.Tensile tests of the Al-4Cu-0.5Mn-2.8γ-Al_(2)O_(3)composite and the Al-4Cu-0.5Mn base alloy after T6 treatment were carried out at room temperature and elevated temperatures(200°C,300°C,and 400°C).Compared with the base alloy,the yield strength of the Al-4Cu-0.5Mn-2.8γ-Al_(2)O_(3)composite after T6 treatment increases significantly from 187 MPa to 263 MPa at room temperature.Simultaneously,at elevated temperatures,the yield strength is also enhanced,with a yield strength of 52 MPa at 400°C for this composite.The in-situ fabricatedγ-Al_(2)O_(3)particles,mainly distributed along the grain boundaries,are supposed to play the main strengthening role,especially at high temperatures.This work acts as a reference for designing composites for high-temperature applications.展开更多
Controlled photocatalytic conversion of CO_(2) into premium fuel such as methane(CH4)offers a sustainable pathway towards a carbon energy cycle.However,the photocatalytic efficiency and selectivity are still unsatisfa...Controlled photocatalytic conversion of CO_(2) into premium fuel such as methane(CH4)offers a sustainable pathway towards a carbon energy cycle.However,the photocatalytic efficiency and selectivity are still unsatisfactory due to the limited availability of active sites on the current photocatalysts.To resolve this issue,the design of oxygen vacancies(OVs)in metal-oxide semiconductors is an effective option.Herein,in situ deposition of TiO_(2) onto SiO_(2) nanospheres to construct a SiO_(2)@TiO_(2) core-shell structure was performed to modulate the oxygen vacancy concentrations.Meanwhile,charge redistribution led to the formation of abundant OV-regulated Ti-Ti(Ti-OV-Ti)dual sites.It is revealed that Ti-OV-Ti dual sites served as the key active site for capturing the photogenerated electrons during light-driven CO_(2) reduction reaction(CO_(2)RR).Such electron-rich active sites enabled efficient CO_(2) adsorption and activation,thus lowering the energy barrier associated with the rate-determining step.More importantly,the formation of a highly stable*CHO intermediate at Ti-OV-Ti dual sites energetically favored the reaction pathway towards the production of CH4 rather than CO,thereby facilitating the selective product of CH_(4).As a result,SiO_(2)@TiO_(2)-50 with an optimized oxygen vacancy concentration of 9.0% showed a remarkable selectivity(90.32%)for CH_(4) production with a rate of 13.21μmol g^(-1) h^(-1),which is 17.38-fold higher than that of pristine TiO_(2).This study provides a new avenue for engineering superior photocatalysts through a rational methodology towards selective reduction of CO_(2).展开更多
Magnesium(Mg)-based composites are expected to be useful for biodegradable bone-implant materials due to their degradability,similar elastic modulus to that of bone,and biofunctionalities.However,their rapid degradati...Magnesium(Mg)-based composites are expected to be useful for biodegradable bone-implant materials due to their degradability,similar elastic modulus to that of bone,and biofunctionalities.However,their rapid degradation,poor biotribology performance,and lack of vascularization and antibacterial activity are not conducive to bone-fixation applications.In this study,an in situ Mg_(2)Ge/Mg-Cu-P composite with a nominal composition of Mg-10Ge-2Cu-0.5P(denoted MGCP)was prepared via phosphorus(P)-modified casting followed by hot extrusion for biodegradable bone-fixation applications.For comparison,an in situ Mg_(2)Ge/Mg-Cu composite(Mg-10Ge-2Cu,denoted MGC)was prepared under the same conditions without P-modification.The hot-extruded(HE)MGCP sample showed significantly improved corrosion resistance with corrosion rates of 2.2 mm/y and 2.51 mm/y as measured by potentiodynamic-polarization and hydrogen-release testing in Dulbecco’s Modified Eagle Medium supplemented with fetal bovine serum(denoted DMEM).The HE MGCP also exhibited notably enhanced mechanical properties and biotribological resistance in DMEM,with an σ_(UTS) of ~304.2 MPa,σ_(TYS) of ~202.5 MPa,elongation of ~12.3%,σ_(UCS) of 769.0 MPa,σ_(CYS) of 208.0 MPa,and Brinell hardness of 105.3 HB,along with smallerσ_(TYS) andσ_(CYS) decreases after 3 d of immersion in Hanks’solution.In comparison to pure titanium and Mg,the HE MGCP demonstrated much greater cytocompatibility,angiogenic capacity,and osteogenic differentiation and mineralization capability.Furthermore,the HE MGCP displayed markedly higher in vitro antibacterial activity,in vivo antibacterial and anti-inflammatory ability,and good biosafety in a rat subcutaneous-implantation model compared to pure titanium and Mg,indicating significant potential for biodegradable bone-fixation applications.展开更多
In-situ TiB_(2)/Al–Cu composite was processed by multidirectional forging(MDF)for six passes.The microstructure evolution of the forged workpiece was examined across various regions.The mechanical properties of the a...In-situ TiB_(2)/Al–Cu composite was processed by multidirectional forging(MDF)for six passes.The microstructure evolution of the forged workpiece was examined across various regions.The mechanical properties of the as-cast and MDFed composites were compared,and their strengthening mechanisms were analyzed.Results indicate that the grain refinement achieved through the MDF process is mainly due to the subdivision of the original grains through mechanical geometric fragmentation and the occurrence of dynamic recrystallization(DRX).DRX grains are formed through discontinuous DRX,continuous DRX,and recrystallization induced by particle-stimulated nucleation.A rise in accumulated equivalent strain(Σ?ε)results in finerα-Al grains and a more uniform distribution of TiB_(2)particles,which enhance the Vickers hardness of the composite.In addition,the tensile properties of the MDFed composite significantly improve compared with those of the as-cast composites,with ultimate tensile strength and yield strength increasing by 51.2%and 54%,respectively.This enhancement is primarily due to grain refinement strengthening and dislocation strengthening achieved by the MDF process.展开更多
Combining Mg and Al dissimilar metals further reduces structural weight,but the formation of intermetallic compounds(IMCs)affectsAl/Mg joint properties.To prevent IMCs,a Ni-Al_(2)O_(3)composite coating was pre-plated ...Combining Mg and Al dissimilar metals further reduces structural weight,but the formation of intermetallic compounds(IMCs)affectsAl/Mg joint properties.To prevent IMCs,a Ni-Al_(2)O_(3)composite coating was pre-plated on the Mg alloy substrate,and then Sn_(3.0)Ag_(0.5)Cu(SAC 305)solder was utilized to facilitate the joining of AZ31 Mg/6061 Al through ultrasonic-assisted soldering.We investigated the impactof Al_(2)O_(3)nano sol content in the coating on microstructure evolution,IMCs formation,and mechanical properties.Results indicated that theNi-Al_(2)O_(3)composite coating effectively suppressed the Mg-Sn reaction,thereby preventing the formation of Mg_(2)Sn IMC and significantlyenhancing joint strength.In joints with a Ni-Al_(2)O_(3)composite coating containing 50 mL/L Al_(2)O_(3)nano sol,no Mg_(2)Sn IMC was detectedafter 50 min of holding at 260℃,achieving a maximum shear strength of approximately 67.2 MPa.Increasing the Al_(2)O_(3)concentrationfurther expanded the soldering process window.For the joint with Ni-Al_(2)O_(3)(100 mL/L Al_(2)O_(3)nano sol)composite coating held at 260℃for 70 min,the coating was dissolved to a thickness of about 5.8μm,but no Mg_(2)Sn IMC was observed.The Ni-based solid solution formednear the coating/solder interface was strengthened,leading to fractures occurring within the SAC solder,and the maximum shear strengthfurther increased to 73.9 MPa.The strengthening mechanism of the joints facilitated by using the Ni-Al_(2)O_(3)composite coating was revealedby comparing with pure Ni-assisted joints.Therefore,employing a Ni-Al_(2)O_(3)composite coating as a barrier layer represents a promisingstrategy for inhibiting IMC formation during the joining of dissimilar metals.展开更多
基金supported by the National Science Fund for Distinguished Young Scholars(No.52225312)National Natu-ral Science Foundation of China(Nos.52271173,52377022,and U23A20548)+1 种基金Key Research and Development Program of Zhejiang Province(No.2021C01193)Zhejiang Provincial Natural Science Foundation of China(No.LY23E010007).
文摘FeSiAl-based soft magnetic composites(SMCs),prepared from insulated FeSiAl powders,are widely applied in electronic devices.However,it is still challenging to achieve high magnetic and mechanical properties simultaneously due to the undesirable insulation layer.Here,double Al_(2)O_(3) insulation layers are prepared for FeSiAl SMC.Atomic-scale characterizations reveal an in-situ epitaxial Al_(2)O_(3) layer at FeSiAl surface under the catalysis of NaAlO_(2),and an outer amorphous Al_(2)O_(3) layer by subsequent NaAlO2 hydrolysis.The above structure ensures effective insulation of FeSiAl powders and excellent magnetic properties of the FeSiAl/NaAlO2 SMC,with permeability of 101 and power loss of 128 mW/cm^(3)(50 mT,100 kHz)respectively.Moreover,in-situ Al_(2)O_(3)/amorphous Al_(2)O_(3) on FeSiAl matrix also leads to distinguished crush strength of 36.5 MPa for the core sample,which is ascribed to the enhanced adhesion at different interfaces as evidenced by similar local oxygen coordination and low strain distribution.This work provides a novel method to fabricate high-performance FeSiAl SMCs.
基金Open Fund of Zhijian Laboratory,Rocket Force University of Engineering(2024-ZJSYS-KF02-09)National Natural Science Foundation of China(51902028,52272034)+1 种基金Key Research and Development Program of Shaanxi(2023JBGS-15)Fundamental Research Funds for the Central Universities(Changan University,300102313202,300102312406)。
文摘To improve the compactness and properties of C/C-SiC-ZrC composites produced by precursor infiltration and pyrolysis(PIP)method,the low-temperature reactive melt infiltration(RMI)process was used to seal the composites using Zr_(2)Cu as the filler.The microstructure,mechanical properties,and ablation properties of the Zr_(2)Cu packed composites were analyzed.Results show that during Zr_(2)Cu impregnation,the melt efficiently fills the large pores of the composites and is converted to ZrCu due to a partial reaction of zirconium with carbon.This results in an increase in composite density from 1.91 g/cm^(3)to 2.24 g/cm^(3)and a reduction in open porosity by 27.35%.Additionally,the flexural strength of Zr_(2)Cu packed C/C-SiC-ZrC composites is improved from 122.78±8.09 MPa to 135.53±5.40 MPa.After plasma ablation for 20 s,the modified composites demonstrate superior ablative resistance compared to PIP C/C-SiC-ZrC,with mass ablation and linear ablation rates of 2.77×10^(−3)g/s and 2.60×10^(−3)mm/s,respectively.The“selftranspiration”effect of the low-melting point copper-containing phase absorbs the heat of the plasma flame,further reducing the ablation temperature and promoting the formation of refined ZrO_(2)particles within the SiO_(2)melting layer.This provides more stable erosion protection for Zr_(2)Cu packed C/C-SiC-ZrC composites.
基金supported by the Shanxi Province Central Guidance Fund for Local Science and Technology Development Project(YDZJSX2024D030)the National Natural Science Foundation of China(22075197,22278290)+2 种基金the Shanxi Province Key Research and Development Program Project(2021020660301013)the Shanxi Provincial Natural Science Foundation of China(202103021224079)the Research and Development Project of Key Core and Common Technology of Shanxi Province(20201102018).
文摘The advancement of planar micro-supercapacitors(PMSCs)for micro-electromechanical systems(MEMS)has been significantly hindered by the challenge of achieving high energy and power densities.This study addresses this issue by leveraging screen-printing technology to fabricate high-performance PMSCs using innovative composite ink.The ink,a synergistic blend of few-layer graphene(Gt),carbon black(CB),and NiCo_(2)O_(4),was meticulously mixed to form a conductive and robust coating that enhanced the capacitive performance of the PMSCs.The optimized ink formulation and printing process result in a micro-supercapacitor with an exceptional areal capacitance of 18.95 mF/cm^(2)and an areal energy density of 2.63μW·h/cm^(2)at a current density of 0.05 mA/cm^(2),along with an areal power density of 0.025 mW/cm^(2).The devices demonstrated impressive durability with a capacitance retention rate of 94.7%after a stringent 20000-cycle test,demonstrating their potential for long-term applications.Moreover,the PMSCs displayed excellent mechanical flexibility,with a capacitance decrease of only 3.43%after 5000 bending cycles,highlighting their suitability for flexible electronic devices.The ease of integrating these PMSCs into series and parallel configurations for customized power further underscores their practicality for integrated power supply solutions in various technologies.
基金Foundation of Northwest Institute for Non-ferrous Metal Research(YK2020-9,ZZXJ2203)Capital Projects of Financial Department of Shaanxi Province(YK22C-12)+4 种基金National Natural Science Foundation of China(62204207)Innovation Capability Support Plan in Shaanxi Province of China(2022KJXX-82,2023KJXX-083)Natural Science Foundation of Shaanxi Province(2022JQ-332)Shaanxi Innovative Research Team for Key Science and Technology(2023-CX-TD-46)Key Research and Development Projects of Shaanxi Province(2024GX-YBXM-351)。
文摘Compared with Cu/Al_(2)O_(3)composites,high-strength Cu/Al_(2)O_(3)composites usually exhibit obviously deteriorated electrical conductivity.A chemical and mechanical alloying-based strategy was adopted to fabricate ultrafine composite powders with lowcontent reinforcement and constructed a combined structure of Cu ultrafine powders covered with in-situ Al_(2)O_(3)nanoparticles.After consolidation at a relatively lower sintering temperature of 550℃,high-volume-fraction ultrafine grains were introduced into the Cu/Al_(2)O_(3)composite,and many in-situ Al_(2)O_(3)nanoparticles with an average size of 11.7±7.5 nm were dispersed homogeneously in the Cu grain.Results show that the composite demonstrates an excellent balance of high tensile strength(654±1 MPa)and high electrical conductivity(84.5±0.1%IACS),which is ascribed to the synergistic strengthening effect of ultrafine grains,dislocations,and in-situ Al_(2)O_(3)nanoparticles.This approach,which utilizes ultrafine composite powder with low-content reinforcement as a precursor and employs low-temperature and high-pressure sintering subsequently,may hold promising potential for large-scale industrial production of high-performance oxide dispersion strengthened alloys.
文摘Photocatalysis is an important process in energy conversion and environmental usage because of its feasible,profitable,and environmentally safe benefits.Coordination chemistry of the CeO_(2)is gaining significant interest because its nanocomposites show unique characteristics namely optically active,wide bandgap(Eg),reversible valence states(Ce^(3+/4+)),rich defect architectures,high O_(2)storage capability,ionic conductivity,and exceptional chemical resistance.Systematically summarized the importance of synthesis methods,particle morphology,and crystal structure aiming at how to heighten the efficacy of CeO_(2)-derived hybrid heterojunction(HHJ)photocatalyst.Selection of an appropriate synthesis method and morphology of the composite materials are beneficial in inhibiting the rapid electron-hole(e^(−)-h^(+))recombination,improvement in visible light adsorption,and large generation of e^(−)-h^(+)pairs to accelerate the photocatalysts activities.Various modification approaches include elemental doping(metal/non-metal doping),heterojunction construction(lower/wide Eg semiconductors(SCD),carbon,conducting polymeric materials),imperfection engineering,and multicomponent hybrid composites.These methods assist as a valuable resource for the rational design of effective CeO_(2)-based composite photocatalysts for sustainable development owing to the enhancement of oxygen species mobility,rapid charge transfer,maximum visible light captivation and slow down the charge recombination rate with increase photogeneration of e−-h+pairs.Also examines the advancements made in CeO_(2)conjugated hybrid composites in photo-oxidation of wastewater effluents(antibiotic/organic dyes/chemical/pharmaceutical),heavy metal removal,H2 production,CO_(2)reduction,and H2O splitting applications.Subsequently,the difficulties and fundamental ideas behind several heterojunction photocatalysts encountered by CeO_(2)-based composites are examined,and future directions for their development are suggested.
文摘Unmanaged wood waste,particularly in countries like Nepal,presents serious environmental concerns due to open burning and improper disposal,leading to carbon emissions,air pollution and land degradation.This study introduces an environmentally sustainable strategy to upcycle Toona ciliata wood scrap—an abundant and underutilized lignocellulosic biomass—into high performance carbon electrodes for green energy storage applications.Activated carbon(TCWAC)was synthesized via single-step pyrolytic carbonization followed by phosphoric acid activation,yielding a material with high specific surface area,hierarchical porosity,and excellent electrical conductivity.Electrochemical measurements using a three-electrode configuration in 6 M KOH revealed optimized potential windows of -1.0 to -0.2 V(TCWAC),-1.2 to 0 V(TCWAC-Mn),and -1.15 to -0.4 V(TCWAC-Fe).TCWAC exhibited a specific capacitance of 156.3 Fg^(-1)at 1 Ag^(-1),with an energy density of 3.5 Whkg^(-1),and 80.2% capacity retention after 1000 charge-discharge cycles.Composites with MnO_(2)and Fe_(2)O_(3)were also evaluated.TWAC-Mn delivered 489.4 Fg^(-1),25.1 Whkg^(-1),and 99.1% retention,whereas,TWAC-Fe achieved 321.3 Fg^(-1),6.3 Whkg^(-1),and 90.3% retention.The superior performance of MnO_(2)is attributed to its multiple oxidation states,facilitating reversible faradaic redox and enhanced pseudocapacitance.This work offers the first direct,systematic comparison of MnO_(2)and Fe_(2)O_(3)composites on a common biomass-carbon matrix under identical synthesis and testing conditions.The finding provides mechanistic insight into charge storage behaviour and demonstrate a scalable route for converting biomass waste into sustainable electrode materials,contributing to cleaner energy solutions and improved biomass valorization.
基金Funded by Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park(No.Z221100006722022)。
文摘We synthesized tungsten-doped vanadium dioxide(W-VO_(2))particles via a one-step hydrothermal method,followed by their integration with antimony-doped tin oxide(ATO)nanoparticles to formulate a composite coating.Subsequently,the VO_(2)/ATO composite coating was fabricated through a spin-coating process.The impact of varying W-VO_(2) content and coating thickness on the performance of the composite coatings was systematically investigated by employing X-ray diffraction,particle size distribution analysis,spectrometry,and other pertinent test methodologies.Our findings revealed that an escalation in both W-VO_(2) content and coating thickness retained high transmittance in the near-infrared band at lower temperatures.However,as the temperature increased,a notable reduction in transmittance in the near-infrared band was observed,alongside a slight decrease in transmittance within the visible band.Remarkably,when the W-VO_(2) content reached 5%and the coating thickness was 1253 nm,the transmittance of the composite coating surpassed 80%.Furthermore,the heat insulation effect achieved a remarkable 10.0℃increase.Consequently,the synthesized composite coating demonstrates significant potential for smart glass applications,particularly in the realm of heat-insulating glass.
文摘BACKGROUND Due to saliva and salivary glands are reservoir to severe acute respiratory syndrome-coronavirus 2(SARS-CoV-2),aerosols and saliva droplets are primary sources of cross-infection and are responsible for the high human–human transmission of SARS-CoV-2.However,there is no evidence about how SARSCoV-2 interacts with oral structures,particularly resin composites.AIM To evaluate the interaction of SARS-CoV-2 proteins with monomers present in resin composites using in silico analysis.METHODS Four SARS-CoV-2 proteins[i.e.main protease,3C-like protease,papain-like protease(PLpro),and glycoprotein spike]were selected along with salivary amylase as the positive control,and their binding affinity with bisphenol-A glycol dimethacrylate,bisphenol-A ethoxylated dimethacrylate,triethylene glycol dimethacrylate,and urethane dimethacrylate was evaluated.Molecular docking was performed using AutoDock Vina and visualised in Chimera UCSF 1.14.The best ligand–protein model was identified based on the binding energy(ΔG–kcal/moL).RESULTS Values for the binding energies ranged from-3.6 kcal/moL to-7.3 kcal/moL.The 3-monomer chain had the lowest binding energy(i.e.highest affinity)to PLpro and the glycoprotein spike.Non-polymerised monomers and polymerised chains interacted with SARS-CoV-2 proteins via hydrogen bonds and hydrophobic interactions.Those findings suggest an interaction between SARS-CoV-2 proteins and resin composites.CONCLUSION SARS-CoV-2 proteins show affinity to non-polymerised and polymerised resin composite chains.
基金supported by the National Natural Science Foundation of China(No.52101138,No.52201075)the Natural Science Foundation of Hubei Province(No.2023AFB798,No.2022CFB614)+3 种基金the Shenzhen Science and Technology Program(No.JCYJ20220530160813032)the State Key Laboratory of Solidification Processing in NWPU(No.SKLSP202309,No.SKLSP202308)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515011227)the State Key Laboratory of Powder Metallurgy of Central South University(No.SklpmKF-05)。
文摘B2-CuZr phase reinforced amorphous alloy matrix composites has become one of the research hotspots in the field of materials science due to the“transformation-induced plasticity”phenomenon,which makes the composites show better macroscopic plastic deformability and obvious work-hardening behavior compared to the conventional amorphous alloy matrix composites reinforced with ductile phases.However,the in-situ metastable B2-CuZr phase tends to undergo eutectoid decomposition during solidification,and the volume fraction,size,and distribution of B2-CuZr phase are difficult to control,which limits the development and application of these materials.To date,much efforts have been made to solve the above problems through composition optimization,casting parameter tailoring,and post-processing technique.In this study,a review was given based on relevant studies,focusing on the predictive approach,reinforcing mechanism,and microstructure tailoring methods of B2-CuZr phase reinforced amorphous alloy matrix composites.The research focus and future prospects were also given for the future development of the present composite system.
基金supported by the National Key R&D Projects(No.2021YFB3702000)the Institute Projects of Ansteel Beijing Research Institute(No.2023BJC-06)the Regional Company Projects in Ansteel Beijing Research Institute(No.2022BJB-18BG&No.2022BJB-13GF).
文摘The Al-Mg_(2)Si in-situ composite is a lightweight material with great potential for application in fields such as automotive lightweighting,aerospace,and electronic components.In this research,the modification,semi-solid technology coupled with different types of electromagnetic stirring was applied to regulate the undesirable solidified dendritic microstructure and facilitate the composites’mechanical properties.The spheroidization and refinement of Mg_(2)Si andα-Al matrix in SM(semi-solid)+RES(rotate electromagnetic stirring)sample and SM+SHES(single winding helical electromagnetic stirring)sample are realized under the effect of fused dendrite arm,the decreased critical nucleate radius,and the increased nucleation rate and extra supercooling degree induced by electromagnetic stirring.The Mg_(2)Si phase in the SM+RES sample and SM+SHES sample is refined by 73.4%and 75.7%,respectively compared to the AC(as-cast)sample.Besides,the single winding electromagnetic stirring can lead to more homogeneously distributed physical fields,lower temperature gradient,and more significant mass transfer,mainly responsible for the more homogeneous distributed reinforced finer Mg_(2)Si particles in the SM+SHES sample.Moreover,both the tensile properties and hardness of modified semi-solid composites are improved through electromagnetic stirring.Compared with RES,the improvement effect of SHES is more excellent.The SM+SHES sample possesses the highest Brinell hardness(124.7 HB),and its quality index of tensile properties is 5.73%and 82.2%higher than that of the SM+RES and AC samples,respectively.
基金supported by the National Key Research and Development Program of China(No.2021YEA1600702)the Natural Science Foundation of Guangxi(ZY24212052)+1 种基金the National Natural Science Foundation of China(Nos.52174356,52301061,52271024,U24A2028 and U22A20174)the Fundamental Research Funds for the Central Universities.
文摘Ultrasonic vibration treatment(UVT)at varying power was successfully applied to the Cu–TiB_(2) composite melt using a SiAlON ceramic sonotrode.The results indicate that TiB_(2) particles are more evenly dispersed in the Cu matrix with increasing ultrasonic power,leading to improved mechanical properties of as-cast composites(≤1000 W).With 1000 W UVT,the distribution of TiB_(2) particles becomes the remarkably uniform and well dispersed,with the size of TiB_(2) particle aggregates decreasing from~50μm without UVT to~5μm.The ultimate tensile strength,yield strength,and elongation of the as-cast composite are 201 MPa,85 MPa,and 28.6%,respectively,representing increases of 21.1%,27.3%,and 43%,respectively,compared to the as-cast composite without UVT.However,when the power is increased to 1500 W,thermal efects are likely to emerge,and the ultrasonic attenuation efect is enhanced,resulting in the re-agglomeration of TiB_(2) particles and a deterioration in performance.By quantitatively analyzing the relationships between sound pressure(Pk),sound energy density(I),sound pulse velocity(V),and ultrasonic power,the infuence mechanism of ultrasonic power on the composite microstructure has been further elucidated and characterized.This study provides crucial guidance for the industrial application of UVT in the fabrication of Cu matrix composites.
基金supported by the National Natural Science Foundation of China(Nos.U2202255 and 52371038)the Science and Technology Innovation Program of Hunan Province(No.2023RC1019).
文摘A novel mechanical stirring-assisted double-melt in-situ reaction casting process was developed to prepare Cu-1TiB2(wt%)composites.The effects of preparation parameters(melting reaction temperature,stirring rate and stirring time)on the microstructure and properties of Cu-1TiB2 composites were investigated.The melt viscosity and particle motion during stirring process were analyzed.The strong turbulence and shear effects generated by mechanical stirring in the melt not only significantly improve the particle distribution but also contribute to adequate in-situ reactions and precise control of the chemical composition.The optimal preparation parameters were 1200℃,a stirring rate of 100 r·min^(−1) and a stirring time of 1 min.Combined with the cold rolling process,the tensile strength,elongation and electrical conductivity of the composite reached 475 MPa,6.0%and 88.4%IACS,respectively,which were significantly better than the composite prepared by manual stirring.The good plasticity is attributed to the uniform distribution of TiB_(2) particles,effectively retarding the crack propagation.The dispersion of particles promotes heterogeneous nucleation of Cu matrix and inhibits grain growth.On the other hand,dispersed particles contribute to grain shear fracture and dislocation multiplication during cold deformation.Therefore,the composite achieves higher dislocation strengthening and grain boundary strengthening.
基金funded by the University of Science and Technology of Hanoi for the emerging research group“Sustainable Energy and Environmental Development” (SEED).
文摘Cost-effective CO_(2) adsorbents are gaining increasing attention as viable solutions for mitigating climate change.In this study,composites were synthesized by electrochemically combining the post-gasification residue of Macadamia nut shell with copper benzene-1,3,5-tricarboxylate(CuBTC).Among the different composites synthesized,the ratio of 1:1 between biochar and CuBTC(B 1:1)demonstrated the highest CO_(2) adsorption capacity.Under controlled laboratory conditions(0℃,1 bar,without the influence of ambient moisture or CO_(2) diffusion limitations),B 1:1 achieved a CO_(2) adsorption capacity of 9.8 mmol/g,while under industrial-like conditions(25℃,1 bar,taking into account the impact of ambient moisture and CO_(2) diffusion limitations within a bed of adsorbent),it reached 6.2 mmol/g.These values surpassed those reported for various advanced CO_(2) adsorbents investigated in previous studies.The superior performance of the B 1:1 composite can be attributed to the optimization of the number of active sites,porosity,and the preservation of the full physical and chemical surface properties of both parentmaterials.Furthermore,the composite exhibited a notable CO_(2)/N_(2) selectivity and improved stability under moisture conditions.These favorable characteristics make B 1:1 a promising candidate for industrial applications.
基金supported by the National Natural Science Foundation of China[52171030]the National Key Research and Development Program of China[2018YFA0702903]。
文摘In this study,a NbB_(2)/AZ91 composite exhibiting desirable mechanical properties was fabricated using a sample casting technique,followed by hard-plate rolling and short-term annealing.The effect of NbB_(2)particles on the microstructural evolution of the AZ91 alloy was investigated.The presence of NbB_(2)was shown to have a grain-refining effect on the AZ91 alloy and promoted dynamic recrystallization(DRX)and precipitation of fine Mg_(17)Al_(12)phases via particle-stimulated nucleation(PSN).Tensile testing revealed substantial enhancements in the ultimate tensile strength(UTS),yield strength(YS),and elongation(EL)of the as-rolled AZ91 alloy,with values of 379 MPa,292 MPa,and 14.7%,respectively,owing to the incorporation of NbB_(2)particles.Annealing led to further enhancements in EL with slight reductions in UTS and YS(360 MPa,252 MPa,and 16.8%,respectively).Owing to grain refinement and the PSN effect of the NbB_(2)particles,a significant number of geometrically necessary dislocations(GNDs)were induced in the matrix during the rolling process,which reduces the nucleation barrier and increases the number of nucleation sites for the recrystallized grains and Mg_(17)Al_(12)precipitates.Meanwhile,many residual dislocations and fine Mg_(17)Al_(12)precipitates in the as-rolled alloys were annihilated during annealing,resulting in slight grain growth and coarsening.The strengthening mechanism of the NbB_(2)/AZ91 composite are mainly associated with grain-refinement strengthening,particle-induced dislocation strengthening,strengthening resulting from mismatching coefficients of thermal expansion(CTE),and heterodeformation-induced(HDI)strengthening.Textural weakening,increased activation of non-basal slip systems,more-uniform strain patterns resulting from NbB_(2)particles,and precipitation are mainly responsible for enhancing ductility.
基金supported by the National Key Research and Development Program of China(No.2022YFB3708400)the National Natural Science Foundation of China(No.52305158)+1 种基金the Young Elite Scientists Sponsorship Program by CAST(No.2022QNRC001)the Science Innovation Foundation of Shanghai Academy of Spaceflight Technology(No.USCAST2021-18).
文摘Mg alloys have the defects of low stiffness,low strength,and high coefficient of thermal expansion(CTE).The composites strategy and its architecture design are effective approaches to improve the comprehensive performance of materials,but the processing difficulty,especially in ceramics forming,limits the control and innovation of material architecture.Here,combined with 3D printing and squeeze infiltration technology,two precisely controllable architectures of AZ91/Al_(2)O_(3)interpenetrating phase composites(IPC)with ceramic scaffold were prepared.The interface,properties and impact of different architecture on IPC performance were studied by experiments and finite element simulation.The metallurgical bonding of the interface was realized with the formation of MgAl_(2)O_(4)reaction layer.The IPC with 1 mm circular hole scaffold(1C-IPC)exhibited significantly improved elastic modulus of 164 GPa,high compressive strength of 680 MPa,and good CTE of 12.91×10^(-6)K^(−1),which were 3.64 times,1.98 times and 55%of the Mg matrix,respectively.Their elastic modulus,compressive strength,and CTE were superior to the vast majority of Mg alloys and Mg based composites.The reinforcement and matrix were bicontinuous and interpenetrating each other,which played a critical role in ensuring the potent strengthening effect of the Al_(2)O_(3)reinforcement by efficient load transfer.Under the same volume fraction of reinforcements,compared to IPC with 1 mm hexagonal hole scaffold(1H-IPC),the elastic modulus and compressive strength of 1C-IPC increased by 15%and 28%,respectively,which was due to the reduced stress concentration and more uniform stress distribution of 1C-IPC.It shows great potential of architecture design in improving the performance of composites.This study provides architectural design strategy and feasible preparation method for the development of high performance materials.
基金supported by the National Natural Science Foundation of China(No.52471040)the Natural Science Foundation of Shandong Province(No.ZR2022ME005).
文摘An Al_(2)O_(3)/Al-Cu-Mn composite was fabricated using a combination of ball milling and liquid-solid reaction,with a nominal composition of Al-4Cu-0.5Mn-2.8γ-Al_(2)O_(3).The composite contains reinforcement particles,including nano-sizedθ’and T(Al_(20)Cu_(2)Mn_(3))particles after T6 heat treatment,as well as in-situ synthesized nano-sizedγ-Al_(2)O_(3)particles.Tensile tests of the Al-4Cu-0.5Mn-2.8γ-Al_(2)O_(3)composite and the Al-4Cu-0.5Mn base alloy after T6 treatment were carried out at room temperature and elevated temperatures(200°C,300°C,and 400°C).Compared with the base alloy,the yield strength of the Al-4Cu-0.5Mn-2.8γ-Al_(2)O_(3)composite after T6 treatment increases significantly from 187 MPa to 263 MPa at room temperature.Simultaneously,at elevated temperatures,the yield strength is also enhanced,with a yield strength of 52 MPa at 400°C for this composite.The in-situ fabricatedγ-Al_(2)O_(3)particles,mainly distributed along the grain boundaries,are supposed to play the main strengthening role,especially at high temperatures.This work acts as a reference for designing composites for high-temperature applications.
基金supported by the National Natural Science Foundation of China(No.21773089,22202037)the Science and Technology Development Plan Project of Jilin Province,China(No.20240101192JC)the Fundamental Research Funds for the Central Universities(No.2412023QD019).
文摘Controlled photocatalytic conversion of CO_(2) into premium fuel such as methane(CH4)offers a sustainable pathway towards a carbon energy cycle.However,the photocatalytic efficiency and selectivity are still unsatisfactory due to the limited availability of active sites on the current photocatalysts.To resolve this issue,the design of oxygen vacancies(OVs)in metal-oxide semiconductors is an effective option.Herein,in situ deposition of TiO_(2) onto SiO_(2) nanospheres to construct a SiO_(2)@TiO_(2) core-shell structure was performed to modulate the oxygen vacancy concentrations.Meanwhile,charge redistribution led to the formation of abundant OV-regulated Ti-Ti(Ti-OV-Ti)dual sites.It is revealed that Ti-OV-Ti dual sites served as the key active site for capturing the photogenerated electrons during light-driven CO_(2) reduction reaction(CO_(2)RR).Such electron-rich active sites enabled efficient CO_(2) adsorption and activation,thus lowering the energy barrier associated with the rate-determining step.More importantly,the formation of a highly stable*CHO intermediate at Ti-OV-Ti dual sites energetically favored the reaction pathway towards the production of CH4 rather than CO,thereby facilitating the selective product of CH_(4).As a result,SiO_(2)@TiO_(2)-50 with an optimized oxygen vacancy concentration of 9.0% showed a remarkable selectivity(90.32%)for CH_(4) production with a rate of 13.21μmol g^(-1) h^(-1),which is 17.38-fold higher than that of pristine TiO_(2).This study provides a new avenue for engineering superior photocatalysts through a rational methodology towards selective reduction of CO_(2).
基金supported by the Zhejiang Public Welfare Technology Application Research Project of China(No.LTGY24H140002,No.LTGY23H140002,No.LGF22H140008)Wenzhou Medical University Basic Scientific Research Expenses Project(KYYW202331)the financial support for this research by the Australian Research Council(ARC)through the Discovery Project(DP240101131).
文摘Magnesium(Mg)-based composites are expected to be useful for biodegradable bone-implant materials due to their degradability,similar elastic modulus to that of bone,and biofunctionalities.However,their rapid degradation,poor biotribology performance,and lack of vascularization and antibacterial activity are not conducive to bone-fixation applications.In this study,an in situ Mg_(2)Ge/Mg-Cu-P composite with a nominal composition of Mg-10Ge-2Cu-0.5P(denoted MGCP)was prepared via phosphorus(P)-modified casting followed by hot extrusion for biodegradable bone-fixation applications.For comparison,an in situ Mg_(2)Ge/Mg-Cu composite(Mg-10Ge-2Cu,denoted MGC)was prepared under the same conditions without P-modification.The hot-extruded(HE)MGCP sample showed significantly improved corrosion resistance with corrosion rates of 2.2 mm/y and 2.51 mm/y as measured by potentiodynamic-polarization and hydrogen-release testing in Dulbecco’s Modified Eagle Medium supplemented with fetal bovine serum(denoted DMEM).The HE MGCP also exhibited notably enhanced mechanical properties and biotribological resistance in DMEM,with an σ_(UTS) of ~304.2 MPa,σ_(TYS) of ~202.5 MPa,elongation of ~12.3%,σ_(UCS) of 769.0 MPa,σ_(CYS) of 208.0 MPa,and Brinell hardness of 105.3 HB,along with smallerσ_(TYS) andσ_(CYS) decreases after 3 d of immersion in Hanks’solution.In comparison to pure titanium and Mg,the HE MGCP demonstrated much greater cytocompatibility,angiogenic capacity,and osteogenic differentiation and mineralization capability.Furthermore,the HE MGCP displayed markedly higher in vitro antibacterial activity,in vivo antibacterial and anti-inflammatory ability,and good biosafety in a rat subcutaneous-implantation model compared to pure titanium and Mg,indicating significant potential for biodegradable bone-fixation applications.
基金supported by the Key Program for International Cooperation of the Ministry of Science and Technology,China(No.ZCGX2022001L)。
文摘In-situ TiB_(2)/Al–Cu composite was processed by multidirectional forging(MDF)for six passes.The microstructure evolution of the forged workpiece was examined across various regions.The mechanical properties of the as-cast and MDFed composites were compared,and their strengthening mechanisms were analyzed.Results indicate that the grain refinement achieved through the MDF process is mainly due to the subdivision of the original grains through mechanical geometric fragmentation and the occurrence of dynamic recrystallization(DRX).DRX grains are formed through discontinuous DRX,continuous DRX,and recrystallization induced by particle-stimulated nucleation.A rise in accumulated equivalent strain(Σ?ε)results in finerα-Al grains and a more uniform distribution of TiB_(2)particles,which enhance the Vickers hardness of the composite.In addition,the tensile properties of the MDFed composite significantly improve compared with those of the as-cast composites,with ultimate tensile strength and yield strength increasing by 51.2%and 54%,respectively.This enhancement is primarily due to grain refinement strengthening and dislocation strengthening achieved by the MDF process.
基金support from the National Natural Science Foundation of China(grant numbers 52275385 and U2167216).
文摘Combining Mg and Al dissimilar metals further reduces structural weight,but the formation of intermetallic compounds(IMCs)affectsAl/Mg joint properties.To prevent IMCs,a Ni-Al_(2)O_(3)composite coating was pre-plated on the Mg alloy substrate,and then Sn_(3.0)Ag_(0.5)Cu(SAC 305)solder was utilized to facilitate the joining of AZ31 Mg/6061 Al through ultrasonic-assisted soldering.We investigated the impactof Al_(2)O_(3)nano sol content in the coating on microstructure evolution,IMCs formation,and mechanical properties.Results indicated that theNi-Al_(2)O_(3)composite coating effectively suppressed the Mg-Sn reaction,thereby preventing the formation of Mg_(2)Sn IMC and significantlyenhancing joint strength.In joints with a Ni-Al_(2)O_(3)composite coating containing 50 mL/L Al_(2)O_(3)nano sol,no Mg_(2)Sn IMC was detectedafter 50 min of holding at 260℃,achieving a maximum shear strength of approximately 67.2 MPa.Increasing the Al_(2)O_(3)concentrationfurther expanded the soldering process window.For the joint with Ni-Al_(2)O_(3)(100 mL/L Al_(2)O_(3)nano sol)composite coating held at 260℃for 70 min,the coating was dissolved to a thickness of about 5.8μm,but no Mg_(2)Sn IMC was observed.The Ni-based solid solution formednear the coating/solder interface was strengthened,leading to fractures occurring within the SAC solder,and the maximum shear strengthfurther increased to 73.9 MPa.The strengthening mechanism of the joints facilitated by using the Ni-Al_(2)O_(3)composite coating was revealedby comparing with pure Ni-assisted joints.Therefore,employing a Ni-Al_(2)O_(3)composite coating as a barrier layer represents a promisingstrategy for inhibiting IMC formation during the joining of dissimilar metals.
