In response to the urgent demand for lightweight,magnesium(Mg)alloys have garnered considerable attention owing to their low density.Nonetheless,the intrinsic poor room-temperature formability of Mg alloys remains a m...In response to the urgent demand for lightweight,magnesium(Mg)alloys have garnered considerable attention owing to their low density.Nonetheless,the intrinsic poor room-temperature formability of Mg alloys remains a major obstacle in shaping precise complex components,necessitating the development of superplastic Mg alloys.Excellent superplasticity is usually acquired in high-alloyed Mg alloys with enhanced microstructural thermal stability facilitated by abundant optimized second-phase particles.While for cost-effective low-alloyed Mg alloys lacking particles,regulating solute segregation has emerged as a promising approach to achieve superplasticity recently.Moreover,the potential of bimodal-grained Mg alloys for superplastic deformation has been revealed,expanding the options for designing superplastic materials beyond the conventional approach of fine-grained microstructures.This study reviews significant developments in superplastic Mg alloys from the view of alloying strategies,grain structure control and deformation mechanisms,with potential implications for future research and industrial applications of superplastic Mg alloys.展开更多
Rolled Mg-Al-Sn series alloys generally possess limited formability due to the formation of strong basal texture.Texture weakening is an effective way to enhance formability,but usually accompanied with decreasing str...Rolled Mg-Al-Sn series alloys generally possess limited formability due to the formation of strong basal texture.Texture weakening is an effective way to enhance formability,but usually accompanied with decreasing strength.In this work,synergistic enhancement of strength and formability is achieved in a Mg-3Al-1Sn-0.5Ca-0.1Sm(ATXS3110)alloy by 0.2 wt.%Mn addition combined with high temperature rolling,exhibiting a high index Erichsen(I.E.)value of~8.1 mm and near-isotropic mechanical properties.On one hand,after Mn addition,the grain refinement from~7.6μm to~4.1μm results in suppression of extension twinning,thereby preventing the development of strong basal texture upon stretch forming.On the other hand,trace Mn addition narrows the grain size distribution and promotes the formation of uniform fine grains,which induces homogeneous deformation during stretch forming.Moreover,grain refinement and high-density nano-sized precipitates caused by trace Mn addition increase the strength.This work may provide insights into designing low-cost Mg-Al-Sn series alloys with superior comprehensive mechanical properties for further structural applications.展开更多
Two sets of alloys,Mg-Zn-Ca-xNi(0≤x≤5),have been developed with tunable corrosion and mechanical properties,optimized for fracturing materials.High-zinc artificial aged(T6)Mg-12Zn-0.5Ca-x Ni(0≤x≤5)series,featuring...Two sets of alloys,Mg-Zn-Ca-xNi(0≤x≤5),have been developed with tunable corrosion and mechanical properties,optimized for fracturing materials.High-zinc artificial aged(T6)Mg-12Zn-0.5Ca-x Ni(0≤x≤5)series,featuring a straightforward preparation method and the potential for manufacturing large-scale components,exhibit notable corrosion rates up to 29 mg cm^(-2)h^(-1)at 25℃ and 643 mg cm^(-2)h^(-1)at 93℃.The high corrosion rate is primary due to the Ni–containing second phases,which intensify the galvanic corrosion that overwhelms their corrosion barrier effect.Low-zinc rolled Mg-1.5Zn-0.2Ca-x Ni(0≤x≤5)series,characterizing excellent deformability with an elongation to failure of~26%,present accelerated corrosion rates up to 34 mg cm^(-2)h^(-1)at 25℃ and 942 mg cm^(-2)h^(-1)at 93℃.The elimination of corrosion barrier effect via deformation contributes to the further increase of corrosion rate compared to the T6 series.Additionally,Mg-Zn-Ca-xNi(0≤x≤5)alloys exhibit tunable ultimate tensile strengths ranging from~190 to~237 MPa,depending on their specific composition.The adjustable corrosion rate and mechanical properties render the Mg-Zn-Ca-x Ni(0≤x≤5)alloys suitable for fracturing materials.展开更多
Conventional rolled Mg-Al alloy sheets typically exhibit strong basal textures that remain and may even strengthen after recrystallization annealing due to the preferential growth of basal-oriented grains,resulting in...Conventional rolled Mg-Al alloy sheets typically exhibit strong basal textures that remain and may even strengthen after recrystallization annealing due to the preferential growth of basal-oriented grains,resulting in poor formability at room temperature.Therefore,the knowledge of recrystallization and grain growth is critical for modifying textures of Mg-Al alloy sheets.The static recrystallization and texture evolution in a cold-rolled dilute Mg-1Al(wt.%)alloy during various annealed temperatures ranging from 300℃ to 450℃,have been investigated using the quasi in-situ electron backscatter diffraction(EBSD)method.The as-rolled Mg-1Al alloy shows a dominant basal texture,which weakens and broadens in the rolling direction(RD)during the subsequent annealing,accompanied by the formation of{1010}texture component.Particularly,the {1010} texture component is more pronounced after annealing at high temperatures.The quasi in-situ EBSD results show that recrystallized grains are mainly induced by shear bands,which exhibit a wide spectrum of orientations with c-axis tilt angles ranging 20°-45°from the normal direction(ND).Orientations of shear band-induced recrystallized grains are retained during the entire recrystallization process,resulting in a reduction in the texture intensity.Moreover,recrystallized grains belonging to the {1010}texture component grow preferentially compared to those with other orientations,which is attributed to low energy grain boundaries,especially grain boundaries with∼30°misorientation angles.Furthermore,the high temperature annealing facilitates the rapid growth of grain boundaries having a 30°misorientation angle,leading to the occurrence of distinct {1010} texture after annealing at 450℃ for 1 h.The results provide insights for texture modification of rare earth-free low-alloyed Mg alloys by controlling annealing parameters.展开更多
The 7 ka old Qixiangzhan lava flow(QXZ,Tianchi volcano)represents the last eruptive event before the 946 CE,caldera-forming‘Millennium’eruption(ME).Petrographic,whole rock,mineral composition,Sr-Nd isotopic data on ...The 7 ka old Qixiangzhan lava flow(QXZ,Tianchi volcano)represents the last eruptive event before the 946 CE,caldera-forming‘Millennium’eruption(ME).Petrographic,whole rock,mineral composition,Sr-Nd isotopic data on QXZ show that:(a)the lava consists of two components,constituted by comenditic obsidian fragments immersed in a continuous,aphanitic component;(b)both components have the same geochemical and isotopic variations of the ME magma.The QXZ and ME comendites result from fractional crystallization and crustal assimilation processes.The temperature of the QXZ magma was about 790℃ and the depth of the magma reservoir around 7 km,the same values as estimated for ME.QXZ had a viscosity of 10^(5.5)-10^(9) Pa s and a velocity of 3-10 km/yr.The emplacement time was 0.5-1.6yr and the flow rate 0.48-1.50 m^(3)/s.These values lie within the range estimated for other rhyolitic flows worldwide.The QXZ lava originated through a mixed explosive-effusive activity with the obsidian resulting from the ascent of undercooling,degassing and the fragmentation of magma along the conduit walls,whereas the aphanitic component testifies to the less undercooled and segregated flow at the center of the conduit.The QXZ lava demonstrates the extensive history of the ME magma chamber.展开更多
Dislocations and disclinations are fundamental topological defects within crystals,which determine the mechanical properties of metals and alloys.Despite their important roles in multiple physical mechanisms,e.g.,dyna...Dislocations and disclinations are fundamental topological defects within crystals,which determine the mechanical properties of metals and alloys.Despite their important roles in multiple physical mechanisms,e.g.,dynamic recovery and grain boundary mediated plasticity,the intrinsic coupling and correlation between disclinations and dislocations,and their impacts on the deformation behavior of metallic materials still remain obscure,partially due to the lack of a theoretical tool to capture the rotational nature of disclinations.By using a Lie-algebra-based theoretical framework,we obtain a general equation to quantify the intrinsic coupling of disclinations and dislocations.Through quasi in-situ electron backscatter diffraction characterizations and disclination/dislocation density analyses in Mg alloys,the generation,coevolution and reactions of disclinations and dislocations during dynamic recovery and superplastic deformation have been quantitatively analyzed.It has been demonstrated that the obtained governing equation can capture multiple physical processes associated with mechanical deformation of metals,e.g.,grain rotation and grain boundary migration,at both room temperature and high temperature.By establishing the disclination-dislocation coupling equation within a Lie algebra description,our work provides new insights for exploring the coevolution and reaction of disclinations/dislocations,with profound implications for elucidating the microstructure-property relationship and underlying deformation mechanisms in metallic materials.展开更多
In this work,a good balance of strength and ductility(a yield strength of 185 MPa and a uniform elongation of 20%)has been obtained in a dilute Mg-1.8Zn-0.3Y-0.3Ca-0.3Zr(wt.%)alloy using hard plate rolling(HPR)followe...In this work,a good balance of strength and ductility(a yield strength of 185 MPa and a uniform elongation of 20%)has been obtained in a dilute Mg-1.8Zn-0.3Y-0.3Ca-0.3Zr(wt.%)alloy using hard plate rolling(HPR)followed by annealing,with a low anisotropy in mechanical properties.More importantly,the HPR-annealed alloy shows an excellent formability at the same time,i.e.,the index Erichsen(I.E.)value reaches 7.9 mm(the Erichsen cupping test)at room temperature,which is higher compared with the Mg-1.8Zn-0.3Y-0.3Ca0.3Zr alloy produced by conventional multi-pass rolling(CR)followed by annealing.The excellent synergy of strength and formability of the HPR-annealed alloy is mainly attributed to a weak elliptical ring texture,as well as finer and denser Zn_(2)Zr_(3)precipitates.The formation of weak elliptical ring texture is related to the preferential co-segregation of Zn and Ca elements at boundaries of basal grains with smal misorientation angles during annealing,which inhibits the growth of basal grains and promotes the preferential growth of non-basal grains At the same time,in comparison with the CR-annealed alloy,the HPR-annealed alloy contains finer and denser Zn_(2)Zr_(3)precipitates that ar less likely to become sources of cracks,leading to the higher strength and formability of the HPR-annealed alloy.The results in this work can provide reference for the development of high strength Mg alloy sheets with excellent room temperature formability,which also shed light on mitigating planar anisotropy in mechanical properties for Mg alloy sheets.展开更多
Electrocatalytic reduction of nitrate pollutants to produce ammonia offers an effective approach to realizing the artificial nitrogen cycle and replacing the energyintensive Haber-Bosch process.Nitrite is an important...Electrocatalytic reduction of nitrate pollutants to produce ammonia offers an effective approach to realizing the artificial nitrogen cycle and replacing the energyintensive Haber-Bosch process.Nitrite is an important intermediate product in the reduction of nitrate to ammonia.Therefore,the mechanism of converting nitrite into ammonia warrants further investigation.Molecular cobalt catalysts are regarded as promising for nitrite reduction reactions(NO_(2)^(−)RR).However,designing and controlling the coordination environment of molecular catalysts is crucial for studying the mechanism of NO_(2)^(−)RR and catalyst design.Herein,we develop a molecular platform of cobalt porphyrin with three coordination microenvironments(Co-N_(3)X_(1),X=N,O,S).Electrochemical experiments demonstrate that cobalt porphyrin with O coordination(CoOTPP)exhibits the lowest onset potential and the highest activity for NO_(2)^(−)RR in ammonia production.Under neutral,nonbuffered conditions over a wide potential range(−1.0 to−1.5 V versus AgCl/Ag),the Faradaic efficiency of nearly 90%for ammonia was achieved and reached 94.5%at−1.4 V versus AgCl/Ag,with an ammonia yield of 6,498μgh^(−1)and a turnover number of 22,869 at−1.5V versus AgCl/Ag.In situ characterization and density functional theory calculations reveal that modulating the coordination environment alters the electron transfer mode of the cobalt active center and the charge redistribution caused by the break of the ligand field.Therefore,this results in enhanced electrochemical activity for NO_(2)^(−)RR in ammonia production.This study provides valuable guidance for designing adjustments to the coordination environment of molecular catalysts to enhance catalytic activity.展开更多
A genus within the family Douvillinidae of the order Strophomenida from the Erdaogou Memberof the Xibiehe Formation in the Early Devonian of central Jilin has been re-examined, with considerationgiven to the 56 specim...A genus within the family Douvillinidae of the order Strophomenida from the Erdaogou Memberof the Xibiehe Formation in the Early Devonian of central Jilin has been re-examined, with considerationgiven to the 56 specimens collected and described by Liu and Huang (1977). Based on its distinct externalornamentation and internal characteristics, it has been classified as Cymostrophia (Protocymostrophia). It isconcluded that the three specices described by Liu and Huang (1977), Idioglyptus alatus, I. semicircularis,I. subquadratus, as well as the Mesodouvillina jilinensis Su, 1980 should be considered synonyms and benamed Cymostrophia (Protocymostrophia) alatus (Liu) Li.展开更多
Photocatalytic solar energy conversion has drawn increasing attention,which holds great potential to deal with the energy crisis and environmental issues.As a typical semiconductor photocatalyst,graphite nitrogen carb...Photocatalytic solar energy conversion has drawn increasing attention,which holds great potential to deal with the energy crisis and environmental issues.As a typical semiconductor photocatalyst,graphite nitrogen carbon(g-C_(3)N_(4))has been widely utilized owing to its nontoxicity and easy preparation properties.However,pristine g-C_(3)N_(4) also faces the limitations of unsatisfactory light absorption,few active sites,and a rapid combination of photo-induced charge.To further optimize the photochemical catalytic performance of g-C_(3)N_(4),tremendous efforts were devoted to modifying g-C_(3)N_(4),including morphological regulation,element doping,and heterogeneous engineering.Some considerable progress has been achieved in g-C_(3)N_(4)-based photocatalytic hydrogen generation(PHE)from water splitting,photocatalytic carbon dioxide reduction(PCR),photocatalytic nitrogen reduction(PNR),photocatalytic removal of pollutants,and photocatalytic bacteria elimination.However,a frontier and comprehensive summary of g-C_(3)N_(4)-based photocatalysis is rarely reported.Herein,we provide an all-inclusive and updated investigation of the recent advances in modification methods of g-C_(3)N_(4) and photocatalytic reactions based on g-C_(3)N_(4) in the past five years.This conclusive remark may provide a new physical insight into the development of g-C_(3)N_(4)-based solar energy conversion.展开更多
High-fidelity tactile rendering offers significant potential for improving the richness and immersion of touchscreen interactions.This study focuses on a quantitative description of tactile rendering fidelity using a ...High-fidelity tactile rendering offers significant potential for improving the richness and immersion of touchscreen interactions.This study focuses on a quantitative description of tactile rendering fidelity using a custom-designed hybrid electrovibration and mechanical vibration(HEM)device.An electrovibration and mechanical vibration(EMV)algorithm that renders 3D gratings with different physical heights was proposed and shown to achieve 81%accuracy in shape recognition.Models of tactile rendering fidelity were established based on the evaluation of the height discrimination threshold,and the psychophysical-physical relationships between the discrimination and reference heights were well described by a modification of Weber’s law,with correlation coefficients higher than 0.9.The physiological-physical relationship between the pulse firing rate and the physical stimulation voltage was modeled using the Izhikevich spiking model with a logarithmic relationship.展开更多
A novel core-shell structured Al_(8)Mn_(4)Y-Al_(2)Ca phase and controllable solute-segregation are elaborately designed in dilute Mg-0.6Al-0.5Mn-0.1Ca-0.1Y alloy(wt.%),via incomplete peritectic transformation during t...A novel core-shell structured Al_(8)Mn_(4)Y-Al_(2)Ca phase and controllable solute-segregation are elaborately designed in dilute Mg-0.6Al-0.5Mn-0.1Ca-0.1Y alloy(wt.%),via incomplete peritectic transformation during twin-roll casting.When soaked in 3.5 wt.%NaCl solution,Al_(2)Ca shell with a low electrochemical potential prevents direct contact of noble Al_(8)Mn_(4)Y with Mg matrix,mitigating the micro-galvanic corrosion and meanwhile accelerating the formation of uniform corrosion film.Thereafter,solute(Al,Ca)-segregation motivates the formation of heterogeneous multilayered corrosion product films,enhancing corrosion resistance and even achieving self-healing upon long-term corrosion.Notably,the dilute Mg alloy exhibits a corrosion rate as low as 0.22±0.05 mm·y^(−1).展开更多
Abnormal grain growth(AGG),a prevalent phenomenon in dilute magnesium(Mg)alloys during elevated-temperature processing,significantly compromises mechanical performance through microstructural degradation.This study in...Abnormal grain growth(AGG),a prevalent phenomenon in dilute magnesium(Mg)alloys during elevated-temperature processing,significantly compromises mechanical performance through microstructural degradation.This study investigates AGG evolution in a heat-treatable Mg-1Al-0.3Ca-0.5Mn(wt.%)alloy,revealing its fundamental mechanism through phase interaction analysis.The AGG initiation is predominantly driven by Zener pinning force attenuation around abnormally coarsened Al_(8)Mn_(5) precipitates.Mechanistically,this heterogeneous coarsening stems from preferential Al_(8)Mn_(5) phase growth kinetics adjacent to Al_(2)Ca phase during homogenization treatment,creating localized pinning force discontinuities.However,addition of 0.2 wt.%Gd facilitates phase transformation from Al_(8)Mn_(5) to thermally stable Al_(8)Mn_(4)Gd with lower Gibbs free energy,thereby promoting a more uniform and refined precipitate distribution.Consequently,the Gd-containing alloy exhibits enhanced grain thermal stability,maintaining a refined microstructure with average grain size of∼7.7μm even after T4 treatment at 500℃ for 1 h,which simultaneously improves strength and ductility compared to the Gd-free alloy.展开更多
To facilitate the industrial application of wrought Mg alloys,this study explores the impact of the rare earth(RE) element Sm on the microstructure and mechanical properties of hot-rolled Mg-1Al-0.3Ca alloy.The result...To facilitate the industrial application of wrought Mg alloys,this study explores the impact of the rare earth(RE) element Sm on the microstructure and mechanical properties of hot-rolled Mg-1Al-0.3Ca alloy.The results indicate that the average grain size and basal texture intensity of the hot-rolled Mg-1 Al-0.7Sm-0.3Ca alloy are significantly reduced compared to the hot-rolled Mg-1Al-0.3Ca alloy.This reduction can be attributed to the pinning effect of grain boundaries and grain refinement facilitated by the presence of the fine Al2Sm phase.Additionally,the addition of Sm leads to an increase in yield strength and ultimate tensile strength,along with a decrease in elongation.This can be attributed to the combined effects of the strengthening mechanism provided by a significant number of Al2Sm particles and the stress concentration occurring at the sharp corners of these particles.Significantly,this study proposes the substitution of expensive RE elements with more cost-effective Sm in the design of Mg alloys for low-alloy systems.The excellent mechanical properties of the Mg-1Al-0.7Sm-0.3Ca alloy provide a reference for the future development of high-performance Mg alloys.展开更多
We report new material of the zalambdalestid,Zhangolestes jilinensis,from the Quantou Formation(lower Upper Cretaceous,Cenomanian to Turonian),Gongzhuling City,Jilin Province,NE China.Using micro-CT-scan,the material ...We report new material of the zalambdalestid,Zhangolestes jilinensis,from the Quantou Formation(lower Upper Cretaceous,Cenomanian to Turonian),Gongzhuling City,Jilin Province,NE China.Using micro-CT-scan,the material is shown to include dentocranial and postcranial elements recovered from the same matrix block containing the holotype specimen.The CT-images also show the labial and internal structures of the holotype fragment of the lower jaw of Z.jilinensis.Based on the preservation,relative size,and tooth wear,the new material and the holotype lower jaw likely belong to the same individual animal,whereas the hypodigm mandibular fragment assigned to Z.jilinensis in the original study is thought now to belong to a different individual,potentially representing a different species,which,if true,would increase the eutherian diversity in the Late Cretaceous Changchunsaurus Fauna.Furthermore,the new CT-images show that the incisor morphology is diverse within zalambdalestids and probably evolved independently from the enlarged incisors in placental mammals,such as Glires.展开更多
The distributions of framework aluminum(Al)in zeolites critically govern the location and speciation of active copper(Cu)centers,thereby influencing their performance in ammonia selective catalytic reduction(NH_(3)-SC...The distributions of framework aluminum(Al)in zeolites critically govern the location and speciation of active copper(Cu)centers,thereby influencing their performance in ammonia selective catalytic reduction(NH_(3)-SCR)of nitrogen oxides(NO_(x)).Conventional Cu-SSZ-39(Cu-SSZ-39-T)exhibits excellent hydrothermal stability but limited low-temperature activity(150–225℃)due to a low concentration of Al in 8-membered rings(8MRs)that inhibits the formation of active[Cu(OH)]^(+)-Z species.Herein,an SSZ-39 zeolite synthesized with potassium ions(SSZ-39-K)achieved a significantly higher 8MR Al fraction(37.6%).Density functional theory calculations and H_(2)-temperature-programmed reduction analyses confirmed that the increased 8MR Al population facilitated the formation of[Cu(OH)]^(+)-Z species.Aged Cu-SSZ-39-K exhibited nearly twice the NO_(x)conversion of aged Cu-SSZ-39-T in the 150–225℃range while maintaining comparable high-temperature activity(250–550℃)under a gas hourly space velocity of 250,000 h^(-1).Enhanced low-temperature performance is particularly beneficial for mitigating NO_(x)emissions during cold-start phase.Moreover,SSZ-39-K was synthesized with a high crystallization yield(~65%),nearly double the highest yield(33%)reported for direct synthesis routes.This work establishes a robust strategy for tailoring Al distributions in SSZ-39 zeolites,offering an effective pathway to improve low-temperature NH_(3)-SCR performance and promote practical implementation.展开更多
The prediction of new fluorooxoborates as ultraviolet(UV)/deep ultraviolet(DUV)opto-electronic functional materials from a largely unexplored chemical space is a challenging task.It has been suggested that the anionic...The prediction of new fluorooxoborates as ultraviolet(UV)/deep ultraviolet(DUV)opto-electronic functional materials from a largely unexplored chemical space is a challenging task.It has been suggested that the anionic frameworks formed by B–O and B–O–F units significantly determine the physical properties of fluorooxoborates.Therefore,the rational design of anionic frameworks could facilitate the materials discovery process.Herein,we propose that a candidate anionic framework can be efficiently derived from an existing one by slightly altering its oxygen content.Following this idea,we hypothesized the existence of a 1D[B_(3)O_(5)F]_(∞)chain from the wellknown 2D[B_(6)O_(9)F_(2_)]_(∞)layer.Accordingly,seven CaB_(3)O_(5)F structures with the expected anionic framework were successfully predicted.First-principles calculations show that all these structures have potential in the UV/DUV birefringent or nonlinear optical(NLO)material field,indicating that the 1D[B_(3)O_(5)F]_(∞)chain is indeed a promising anionic framework for achieving UV/DUV birefringent and NLO performance.展开更多
Aqueous rechargeable zinc-ion batteries(ZIBs)have recently attracted increasing research interest due to their unparalleled safety,fantastic cost competitiveness and promising capacity advantages compared with the com...Aqueous rechargeable zinc-ion batteries(ZIBs)have recently attracted increasing research interest due to their unparalleled safety,fantastic cost competitiveness and promising capacity advantages compared with the commercial lithium ion batteries.However,the disputed energy storage mechanism has been a confusing issue restraining the development of ZIBs.Although a lot of efforts have been dedicated to the exploration in battery chemistry,a comprehensive review that focuses on summarizing the energy storage mechanisms of ZIBs is needed.Herein,the energy storage mechanisms of aqueous rechargeable ZIBs are systematically reviewed in detail and summarized as four types,which are traditional Zn^(2+)insertion chemistry,dual ions co-insertion,chemical conversion reaction and coordination reaction of Zn^(2+)with organic cathodes.Furthermore,the promising exploration directions and rational prospects are also proposed in this review.展开更多
The effect of large thickness-reduction on microstructure evolution and tensile properties of Mg-9 Al-1 Zn alloy(AZ91)processed by hard-plate rolling(HPR)was investigated.Increasing rolling reduction from55%to 85%incr...The effect of large thickness-reduction on microstructure evolution and tensile properties of Mg-9 Al-1 Zn alloy(AZ91)processed by hard-plate rolling(HPR)was investigated.Increasing rolling reduction from55%to 85%increases the volume fraction and refines average size of fine grains(<3μm,FGs),leading to an optimized bimodal-grained structure consisting of coarse grains(CGs)uniformly embedded in FG regions.The sample with 85%reduction exhibits the highest yield strength of~314 MPa,ultimate tensile strength of~381 MPa and elongation of~11%.The high strength is primarily due to the contribution of grain boundaries(GBs)strengthening by FGs(accounting for~65%of strength),meanwhile the improved ductility originates from the optimized bimodal-grained structure and weakened basal texture that favor a higher ductility.The present findings successfully overcome the trade-off dilemma that the largereduction rolling processing on Mg alloys usually enhances strength at expense of ductility.In addition,the intensified heterogeneous deformation and favorable formation of a bimodal-grained microstructure during large-reduct ion HPR was addressed by tracing micro structure evolution details in grains of intere st via quasi-in-situ electron back scattering diffraction(EBSD).The present study can be instructive for further designing novel Mg alloys by tailoring bimodal-grained structures for superior combination of mechanical properties.展开更多
Grain boundary strengthening is an effective strategy for increasing mechanical properties of Mg alloys.However,this method offers limited strengthening in bimodal grain-structured Mg alloys due to the difficultly in ...Grain boundary strengthening is an effective strategy for increasing mechanical properties of Mg alloys.However,this method offers limited strengthening in bimodal grain-structured Mg alloys due to the difficultly in increasing the volume fraction of fine grains while keeping a small grain size.Herein,we show that the volume fraction of fine grains(FGs,~2.5μm)in the bimodal grain structure can be tailored from~30 vol.%in Mg-9 Al-1 Zn(AZ91)to~52 vol.%in AZ91-1Y(wt.%)processed by hard plate rolling(HPR).Moreover,a superior combination of a high ultimate tensile strength(~405 MPa)and decent uniform elongation(~9%)is achieved in present AZ91-1Y alloy.It reveals that a desired bimodal grain structure can be tailored by the co-regulating effect from coarse Al_(2)Y particles resulting in inhomogeneous recrystallization,and dispersed submicron Mg_(17)Al_(12)particles depressing the growth of recrystallized grains.The findings offer a valuable insight in tailoring bimodal grain-structured Mg alloys for optimized strength and ductility.展开更多
基金primarily supported by The National Natural Science Foundation of China(under Nos.52234009 and 52271103)Partial financial support came from the Program for the Central University Youth Innovation Team(No.419021423505)the Fundamental Research Funds for the Central Universities,JLU.
文摘In response to the urgent demand for lightweight,magnesium(Mg)alloys have garnered considerable attention owing to their low density.Nonetheless,the intrinsic poor room-temperature formability of Mg alloys remains a major obstacle in shaping precise complex components,necessitating the development of superplastic Mg alloys.Excellent superplasticity is usually acquired in high-alloyed Mg alloys with enhanced microstructural thermal stability facilitated by abundant optimized second-phase particles.While for cost-effective low-alloyed Mg alloys lacking particles,regulating solute segregation has emerged as a promising approach to achieve superplasticity recently.Moreover,the potential of bimodal-grained Mg alloys for superplastic deformation has been revealed,expanding the options for designing superplastic materials beyond the conventional approach of fine-grained microstructures.This study reviews significant developments in superplastic Mg alloys from the view of alloying strategies,grain structure control and deformation mechanisms,with potential implications for future research and industrial applications of superplastic Mg alloys.
基金supported by The National Natural Science Foundation of China(under Nos.52234009,U19A2084,52171116,U22A20109,52201113)Partial financial support came from Program for the Central University Youth Innovation Team(419021423505)+2 种基金the Fundamental Research Funds for the Central Universities(No.2412022QD037)the Excellent Youth Program of Jilin Provincial Department of Education(JJKH20241425KJ)the Fundamental Research Funds for the Central Universities,JLU.
文摘Rolled Mg-Al-Sn series alloys generally possess limited formability due to the formation of strong basal texture.Texture weakening is an effective way to enhance formability,but usually accompanied with decreasing strength.In this work,synergistic enhancement of strength and formability is achieved in a Mg-3Al-1Sn-0.5Ca-0.1Sm(ATXS3110)alloy by 0.2 wt.%Mn addition combined with high temperature rolling,exhibiting a high index Erichsen(I.E.)value of~8.1 mm and near-isotropic mechanical properties.On one hand,after Mn addition,the grain refinement from~7.6μm to~4.1μm results in suppression of extension twinning,thereby preventing the development of strong basal texture upon stretch forming.On the other hand,trace Mn addition narrows the grain size distribution and promotes the formation of uniform fine grains,which induces homogeneous deformation during stretch forming.Moreover,grain refinement and high-density nano-sized precipitates caused by trace Mn addition increase the strength.This work may provide insights into designing low-cost Mg-Al-Sn series alloys with superior comprehensive mechanical properties for further structural applications.
基金supported by the National Key Research and Development Program(No.2022YFE0122000)National Natural Science Foundation of China under Grant Nos.52234009,52274383,52222409,and 52201113。
文摘Two sets of alloys,Mg-Zn-Ca-xNi(0≤x≤5),have been developed with tunable corrosion and mechanical properties,optimized for fracturing materials.High-zinc artificial aged(T6)Mg-12Zn-0.5Ca-x Ni(0≤x≤5)series,featuring a straightforward preparation method and the potential for manufacturing large-scale components,exhibit notable corrosion rates up to 29 mg cm^(-2)h^(-1)at 25℃ and 643 mg cm^(-2)h^(-1)at 93℃.The high corrosion rate is primary due to the Ni–containing second phases,which intensify the galvanic corrosion that overwhelms their corrosion barrier effect.Low-zinc rolled Mg-1.5Zn-0.2Ca-x Ni(0≤x≤5)series,characterizing excellent deformability with an elongation to failure of~26%,present accelerated corrosion rates up to 34 mg cm^(-2)h^(-1)at 25℃ and 942 mg cm^(-2)h^(-1)at 93℃.The elimination of corrosion barrier effect via deformation contributes to the further increase of corrosion rate compared to the T6 series.Additionally,Mg-Zn-Ca-xNi(0≤x≤5)alloys exhibit tunable ultimate tensile strengths ranging from~190 to~237 MPa,depending on their specific composition.The adjustable corrosion rate and mechanical properties render the Mg-Zn-Ca-x Ni(0≤x≤5)alloys suitable for fracturing materials.
基金by National Natural Science Foundation of China(Nos.52271103,52334010 and 52271031)Jilin Scientific and Technological Development Program(Nos.20220301026GX,20210201115GX and 20210301041GX).
文摘Conventional rolled Mg-Al alloy sheets typically exhibit strong basal textures that remain and may even strengthen after recrystallization annealing due to the preferential growth of basal-oriented grains,resulting in poor formability at room temperature.Therefore,the knowledge of recrystallization and grain growth is critical for modifying textures of Mg-Al alloy sheets.The static recrystallization and texture evolution in a cold-rolled dilute Mg-1Al(wt.%)alloy during various annealed temperatures ranging from 300℃ to 450℃,have been investigated using the quasi in-situ electron backscatter diffraction(EBSD)method.The as-rolled Mg-1Al alloy shows a dominant basal texture,which weakens and broadens in the rolling direction(RD)during the subsequent annealing,accompanied by the formation of{1010}texture component.Particularly,the {1010} texture component is more pronounced after annealing at high temperatures.The quasi in-situ EBSD results show that recrystallized grains are mainly induced by shear bands,which exhibit a wide spectrum of orientations with c-axis tilt angles ranging 20°-45°from the normal direction(ND).Orientations of shear band-induced recrystallized grains are retained during the entire recrystallization process,resulting in a reduction in the texture intensity.Moreover,recrystallized grains belonging to the {1010}texture component grow preferentially compared to those with other orientations,which is attributed to low energy grain boundaries,especially grain boundaries with∼30°misorientation angles.Furthermore,the high temperature annealing facilitates the rapid growth of grain boundaries having a 30°misorientation angle,leading to the occurrence of distinct {1010} texture after annealing at 450℃ for 1 h.The results provide insights for texture modification of rare earth-free low-alloyed Mg alloys by controlling annealing parameters.
基金funded by the National Natural Science Foundation of China(Grant Nos.41972313 and 41790453)the Engineering Research Center of Geothermal Resources Development Technology and Equipment,Ministry of Education,Jilin University。
文摘The 7 ka old Qixiangzhan lava flow(QXZ,Tianchi volcano)represents the last eruptive event before the 946 CE,caldera-forming‘Millennium’eruption(ME).Petrographic,whole rock,mineral composition,Sr-Nd isotopic data on QXZ show that:(a)the lava consists of two components,constituted by comenditic obsidian fragments immersed in a continuous,aphanitic component;(b)both components have the same geochemical and isotopic variations of the ME magma.The QXZ and ME comendites result from fractional crystallization and crustal assimilation processes.The temperature of the QXZ magma was about 790℃ and the depth of the magma reservoir around 7 km,the same values as estimated for ME.QXZ had a viscosity of 10^(5.5)-10^(9) Pa s and a velocity of 3-10 km/yr.The emplacement time was 0.5-1.6yr and the flow rate 0.48-1.50 m^(3)/s.These values lie within the range estimated for other rhyolitic flows worldwide.The QXZ lava originated through a mixed explosive-effusive activity with the obsidian resulting from the ascent of undercooling,degassing and the fragmentation of magma along the conduit walls,whereas the aphanitic component testifies to the less undercooled and segregated flow at the center of the conduit.The QXZ lava demonstrates the extensive history of the ME magma chamber.
基金Financial supports from the National Natural Science Foundation of China(Nos.52171116,U22A20109,52334010 and T2325013)are greatly acknowledgedPartial financial support came from The Program for the Central University Youth Innovation Team,and the Fundamental Research Funds for the Central Universities,JLU.
文摘Dislocations and disclinations are fundamental topological defects within crystals,which determine the mechanical properties of metals and alloys.Despite their important roles in multiple physical mechanisms,e.g.,dynamic recovery and grain boundary mediated plasticity,the intrinsic coupling and correlation between disclinations and dislocations,and their impacts on the deformation behavior of metallic materials still remain obscure,partially due to the lack of a theoretical tool to capture the rotational nature of disclinations.By using a Lie-algebra-based theoretical framework,we obtain a general equation to quantify the intrinsic coupling of disclinations and dislocations.Through quasi in-situ electron backscatter diffraction characterizations and disclination/dislocation density analyses in Mg alloys,the generation,coevolution and reactions of disclinations and dislocations during dynamic recovery and superplastic deformation have been quantitatively analyzed.It has been demonstrated that the obtained governing equation can capture multiple physical processes associated with mechanical deformation of metals,e.g.,grain rotation and grain boundary migration,at both room temperature and high temperature.By establishing the disclination-dislocation coupling equation within a Lie algebra description,our work provides new insights for exploring the coevolution and reaction of disclinations/dislocations,with profound implications for elucidating the microstructure-property relationship and underlying deformation mechanisms in metallic materials.
基金Tral Science Foundation of China(Nos.52271103,52334010and 52271031)Partial financial support came from JilinScientific and Technological Development Program(No.20220301026GX)Program for the Central UniversityYouth Innovation Team。
文摘In this work,a good balance of strength and ductility(a yield strength of 185 MPa and a uniform elongation of 20%)has been obtained in a dilute Mg-1.8Zn-0.3Y-0.3Ca-0.3Zr(wt.%)alloy using hard plate rolling(HPR)followed by annealing,with a low anisotropy in mechanical properties.More importantly,the HPR-annealed alloy shows an excellent formability at the same time,i.e.,the index Erichsen(I.E.)value reaches 7.9 mm(the Erichsen cupping test)at room temperature,which is higher compared with the Mg-1.8Zn-0.3Y-0.3Ca0.3Zr alloy produced by conventional multi-pass rolling(CR)followed by annealing.The excellent synergy of strength and formability of the HPR-annealed alloy is mainly attributed to a weak elliptical ring texture,as well as finer and denser Zn_(2)Zr_(3)precipitates.The formation of weak elliptical ring texture is related to the preferential co-segregation of Zn and Ca elements at boundaries of basal grains with smal misorientation angles during annealing,which inhibits the growth of basal grains and promotes the preferential growth of non-basal grains At the same time,in comparison with the CR-annealed alloy,the HPR-annealed alloy contains finer and denser Zn_(2)Zr_(3)precipitates that ar less likely to become sources of cracks,leading to the higher strength and formability of the HPR-annealed alloy.The results in this work can provide reference for the development of high strength Mg alloy sheets with excellent room temperature formability,which also shed light on mitigating planar anisotropy in mechanical properties for Mg alloy sheets.
基金National Key Research and Development Program of China,Grant/Award Number:2022YFC2105800National Natural Science Foundation of China,Grant/Award Numbers:21901084,21905106,22279041+2 种基金Higher Education Discipline Innovation Project,Grant/Award Number:B17020Specific Research Fund of the Innovation Platform for Academicians of Hainan Province,China,Grant/Award Number:YSPTZX202321Natural Science Foundation of Jilin Province,Grant/Award Number:SKL202302017.
文摘Electrocatalytic reduction of nitrate pollutants to produce ammonia offers an effective approach to realizing the artificial nitrogen cycle and replacing the energyintensive Haber-Bosch process.Nitrite is an important intermediate product in the reduction of nitrate to ammonia.Therefore,the mechanism of converting nitrite into ammonia warrants further investigation.Molecular cobalt catalysts are regarded as promising for nitrite reduction reactions(NO_(2)^(−)RR).However,designing and controlling the coordination environment of molecular catalysts is crucial for studying the mechanism of NO_(2)^(−)RR and catalyst design.Herein,we develop a molecular platform of cobalt porphyrin with three coordination microenvironments(Co-N_(3)X_(1),X=N,O,S).Electrochemical experiments demonstrate that cobalt porphyrin with O coordination(CoOTPP)exhibits the lowest onset potential and the highest activity for NO_(2)^(−)RR in ammonia production.Under neutral,nonbuffered conditions over a wide potential range(−1.0 to−1.5 V versus AgCl/Ag),the Faradaic efficiency of nearly 90%for ammonia was achieved and reached 94.5%at−1.4 V versus AgCl/Ag,with an ammonia yield of 6,498μgh^(−1)and a turnover number of 22,869 at−1.5V versus AgCl/Ag.In situ characterization and density functional theory calculations reveal that modulating the coordination environment alters the electron transfer mode of the cobalt active center and the charge redistribution caused by the break of the ligand field.Therefore,this results in enhanced electrochemical activity for NO_(2)^(−)RR in ammonia production.This study provides valuable guidance for designing adjustments to the coordination environment of molecular catalysts to enhance catalytic activity.
基金Supported by the National Natural Science Foundation of China Nos.41702011 and 41372019.
文摘A genus within the family Douvillinidae of the order Strophomenida from the Erdaogou Memberof the Xibiehe Formation in the Early Devonian of central Jilin has been re-examined, with considerationgiven to the 56 specimens collected and described by Liu and Huang (1977). Based on its distinct externalornamentation and internal characteristics, it has been classified as Cymostrophia (Protocymostrophia). It isconcluded that the three specices described by Liu and Huang (1977), Idioglyptus alatus, I. semicircularis,I. subquadratus, as well as the Mesodouvillina jilinensis Su, 1980 should be considered synonyms and benamed Cymostrophia (Protocymostrophia) alatus (Liu) Li.
基金supported by Jilin youth growth science and technology plan project(No.20220508019RC)the“Interdisciplinary integration and innovation”project of Jilin University in 2021(No.JLUXKJC2021QZ06)+6 种基金the Natural Science Foundation of Jilin Province(No.SKL202302017)the National Natural Science Foundation of China(Nos.22279041,22301099,and 82302277)the National Key Research and Development Program of China(No.2022YFC2105800)the 111 Project(No.B17020)the Science and Technology Innovation Program of Hunan Province(No.2022RC1232)Provincial Natural Science Foundation of Hunan(Grant No.2023JJ40087)Research Foundation of Education Bureau of Hunan Province(No.22B0896).
文摘Photocatalytic solar energy conversion has drawn increasing attention,which holds great potential to deal with the energy crisis and environmental issues.As a typical semiconductor photocatalyst,graphite nitrogen carbon(g-C_(3)N_(4))has been widely utilized owing to its nontoxicity and easy preparation properties.However,pristine g-C_(3)N_(4) also faces the limitations of unsatisfactory light absorption,few active sites,and a rapid combination of photo-induced charge.To further optimize the photochemical catalytic performance of g-C_(3)N_(4),tremendous efforts were devoted to modifying g-C_(3)N_(4),including morphological regulation,element doping,and heterogeneous engineering.Some considerable progress has been achieved in g-C_(3)N_(4)-based photocatalytic hydrogen generation(PHE)from water splitting,photocatalytic carbon dioxide reduction(PCR),photocatalytic nitrogen reduction(PNR),photocatalytic removal of pollutants,and photocatalytic bacteria elimination.However,a frontier and comprehensive summary of g-C_(3)N_(4)-based photocatalysis is rarely reported.Herein,we provide an all-inclusive and updated investigation of the recent advances in modification methods of g-C_(3)N_(4) and photocatalytic reactions based on g-C_(3)N_(4) in the past five years.This conclusive remark may provide a new physical insight into the development of g-C_(3)N_(4)-based solar energy conversion.
基金Supported by the National Natural Science Foundation of China under Grants 61631010 and 61806085.
文摘High-fidelity tactile rendering offers significant potential for improving the richness and immersion of touchscreen interactions.This study focuses on a quantitative description of tactile rendering fidelity using a custom-designed hybrid electrovibration and mechanical vibration(HEM)device.An electrovibration and mechanical vibration(EMV)algorithm that renders 3D gratings with different physical heights was proposed and shown to achieve 81%accuracy in shape recognition.Models of tactile rendering fidelity were established based on the evaluation of the height discrimination threshold,and the psychophysical-physical relationships between the discrimination and reference heights were well described by a modification of Weber’s law,with correlation coefficients higher than 0.9.The physiological-physical relationship between the pulse firing rate and the physical stimulation voltage was modeled using the Izhikevich spiking model with a logarithmic relationship.
基金supported by National Natural Science Foundation of China under Grant Nos.52234009 and 52274383Partial financial support came from the Fundamental Research Funds for the Central Universities,JLU,Program for JLU Science and Technology Innovative Research Team(JLUSTIRT,2017TD-09)Program for the Central University Youth Innovation Team.
文摘A novel core-shell structured Al_(8)Mn_(4)Y-Al_(2)Ca phase and controllable solute-segregation are elaborately designed in dilute Mg-0.6Al-0.5Mn-0.1Ca-0.1Y alloy(wt.%),via incomplete peritectic transformation during twin-roll casting.When soaked in 3.5 wt.%NaCl solution,Al_(2)Ca shell with a low electrochemical potential prevents direct contact of noble Al_(8)Mn_(4)Y with Mg matrix,mitigating the micro-galvanic corrosion and meanwhile accelerating the formation of uniform corrosion film.Thereafter,solute(Al,Ca)-segregation motivates the formation of heterogeneous multilayered corrosion product films,enhancing corrosion resistance and even achieving self-healing upon long-term corrosion.Notably,the dilute Mg alloy exhibits a corrosion rate as low as 0.22±0.05 mm·y^(−1).
基金supports from The National Natural Science Foundation of China (Nos. 52222409, U24A20104 and 52401049)The National Key Research and Development Program (No. 2024YFB3408900) are greatly acknowledgedPartial financial support came from the Fundamental Research Funds for the Central Universities, JLU
文摘Abnormal grain growth(AGG),a prevalent phenomenon in dilute magnesium(Mg)alloys during elevated-temperature processing,significantly compromises mechanical performance through microstructural degradation.This study investigates AGG evolution in a heat-treatable Mg-1Al-0.3Ca-0.5Mn(wt.%)alloy,revealing its fundamental mechanism through phase interaction analysis.The AGG initiation is predominantly driven by Zener pinning force attenuation around abnormally coarsened Al_(8)Mn_(5) precipitates.Mechanistically,this heterogeneous coarsening stems from preferential Al_(8)Mn_(5) phase growth kinetics adjacent to Al_(2)Ca phase during homogenization treatment,creating localized pinning force discontinuities.However,addition of 0.2 wt.%Gd facilitates phase transformation from Al_(8)Mn_(5) to thermally stable Al_(8)Mn_(4)Gd with lower Gibbs free energy,thereby promoting a more uniform and refined precipitate distribution.Consequently,the Gd-containing alloy exhibits enhanced grain thermal stability,maintaining a refined microstructure with average grain size of∼7.7μm even after T4 treatment at 500℃ for 1 h,which simultaneously improves strength and ductility compared to the Gd-free alloy.
文摘To facilitate the industrial application of wrought Mg alloys,this study explores the impact of the rare earth(RE) element Sm on the microstructure and mechanical properties of hot-rolled Mg-1Al-0.3Ca alloy.The results indicate that the average grain size and basal texture intensity of the hot-rolled Mg-1 Al-0.7Sm-0.3Ca alloy are significantly reduced compared to the hot-rolled Mg-1Al-0.3Ca alloy.This reduction can be attributed to the pinning effect of grain boundaries and grain refinement facilitated by the presence of the fine Al2Sm phase.Additionally,the addition of Sm leads to an increase in yield strength and ultimate tensile strength,along with a decrease in elongation.This can be attributed to the combined effects of the strengthening mechanism provided by a significant number of Al2Sm particles and the stress concentration occurring at the sharp corners of these particles.Significantly,this study proposes the substitution of expensive RE elements with more cost-effective Sm in the design of Mg alloys for low-alloy systems.The excellent mechanical properties of the Mg-1Al-0.7Sm-0.3Ca alloy provide a reference for the future development of high-performance Mg alloys.
基金supported by the National Natural Science Foundation of China(Grant Nos.42122010,42072017)the Youth Innovation Promotion Association CAS(Y2023017)+1 种基金the National Mineral Rock and Fossil Specimens Resource Center(NCSTI-RMF20240203)China Geological Survey(DD20230221)。
文摘We report new material of the zalambdalestid,Zhangolestes jilinensis,from the Quantou Formation(lower Upper Cretaceous,Cenomanian to Turonian),Gongzhuling City,Jilin Province,NE China.Using micro-CT-scan,the material is shown to include dentocranial and postcranial elements recovered from the same matrix block containing the holotype specimen.The CT-images also show the labial and internal structures of the holotype fragment of the lower jaw of Z.jilinensis.Based on the preservation,relative size,and tooth wear,the new material and the holotype lower jaw likely belong to the same individual animal,whereas the hypodigm mandibular fragment assigned to Z.jilinensis in the original study is thought now to belong to a different individual,potentially representing a different species,which,if true,would increase the eutherian diversity in the Late Cretaceous Changchunsaurus Fauna.Furthermore,the new CT-images show that the incisor morphology is diverse within zalambdalestids and probably evolved independently from the enlarged incisors in placental mammals,such as Glires.
文摘The distributions of framework aluminum(Al)in zeolites critically govern the location and speciation of active copper(Cu)centers,thereby influencing their performance in ammonia selective catalytic reduction(NH_(3)-SCR)of nitrogen oxides(NO_(x)).Conventional Cu-SSZ-39(Cu-SSZ-39-T)exhibits excellent hydrothermal stability but limited low-temperature activity(150–225℃)due to a low concentration of Al in 8-membered rings(8MRs)that inhibits the formation of active[Cu(OH)]^(+)-Z species.Herein,an SSZ-39 zeolite synthesized with potassium ions(SSZ-39-K)achieved a significantly higher 8MR Al fraction(37.6%).Density functional theory calculations and H_(2)-temperature-programmed reduction analyses confirmed that the increased 8MR Al population facilitated the formation of[Cu(OH)]^(+)-Z species.Aged Cu-SSZ-39-K exhibited nearly twice the NO_(x)conversion of aged Cu-SSZ-39-T in the 150–225℃range while maintaining comparable high-temperature activity(250–550℃)under a gas hourly space velocity of 250,000 h^(-1).Enhanced low-temperature performance is particularly beneficial for mitigating NO_(x)emissions during cold-start phase.Moreover,SSZ-39-K was synthesized with a high crystallization yield(~65%),nearly double the highest yield(33%)reported for direct synthesis routes.This work establishes a robust strategy for tailoring Al distributions in SSZ-39 zeolites,offering an effective pathway to improve low-temperature NH_(3)-SCR performance and promote practical implementation.
基金supported by the National Natural Science Foundation of China(Grant No.52403305)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0880000)+1 种基金Tianchi Talent Program of Xinjiang Uygur Autonomous Region(Grant No.2024000068)Postdoctoral Fellow-ship Program(Grade C)(Grant No.GZC20232959)。
文摘The prediction of new fluorooxoborates as ultraviolet(UV)/deep ultraviolet(DUV)opto-electronic functional materials from a largely unexplored chemical space is a challenging task.It has been suggested that the anionic frameworks formed by B–O and B–O–F units significantly determine the physical properties of fluorooxoborates.Therefore,the rational design of anionic frameworks could facilitate the materials discovery process.Herein,we propose that a candidate anionic framework can be efficiently derived from an existing one by slightly altering its oxygen content.Following this idea,we hypothesized the existence of a 1D[B_(3)O_(5)F]_(∞)chain from the wellknown 2D[B_(6)O_(9)F_(2_)]_(∞)layer.Accordingly,seven CaB_(3)O_(5)F structures with the expected anionic framework were successfully predicted.First-principles calculations show that all these structures have potential in the UV/DUV birefringent or nonlinear optical(NLO)material field,indicating that the 1D[B_(3)O_(5)F]_(∞)chain is indeed a promising anionic framework for achieving UV/DUV birefringent and NLO performance.
基金supported by the National Natural Science Foundation of China(21571080)。
文摘Aqueous rechargeable zinc-ion batteries(ZIBs)have recently attracted increasing research interest due to their unparalleled safety,fantastic cost competitiveness and promising capacity advantages compared with the commercial lithium ion batteries.However,the disputed energy storage mechanism has been a confusing issue restraining the development of ZIBs.Although a lot of efforts have been dedicated to the exploration in battery chemistry,a comprehensive review that focuses on summarizing the energy storage mechanisms of ZIBs is needed.Herein,the energy storage mechanisms of aqueous rechargeable ZIBs are systematically reviewed in detail and summarized as four types,which are traditional Zn^(2+)insertion chemistry,dual ions co-insertion,chemical conversion reaction and coordination reaction of Zn^(2+)with organic cathodes.Furthermore,the promising exploration directions and rational prospects are also proposed in this review.
基金supported by the Natural Science Foundation of China(Nos.51922048,51625402,51871108 and 51671093)Partial financial support came from the Changjiang Scholars Program(No.T2017035)。
文摘The effect of large thickness-reduction on microstructure evolution and tensile properties of Mg-9 Al-1 Zn alloy(AZ91)processed by hard-plate rolling(HPR)was investigated.Increasing rolling reduction from55%to 85%increases the volume fraction and refines average size of fine grains(<3μm,FGs),leading to an optimized bimodal-grained structure consisting of coarse grains(CGs)uniformly embedded in FG regions.The sample with 85%reduction exhibits the highest yield strength of~314 MPa,ultimate tensile strength of~381 MPa and elongation of~11%.The high strength is primarily due to the contribution of grain boundaries(GBs)strengthening by FGs(accounting for~65%of strength),meanwhile the improved ductility originates from the optimized bimodal-grained structure and weakened basal texture that favor a higher ductility.The present findings successfully overcome the trade-off dilemma that the largereduction rolling processing on Mg alloys usually enhances strength at expense of ductility.In addition,the intensified heterogeneous deformation and favorable formation of a bimodal-grained microstructure during large-reduct ion HPR was addressed by tracing micro structure evolution details in grains of intere st via quasi-in-situ electron back scattering diffraction(EBSD).The present study can be instructive for further designing novel Mg alloys by tailoring bimodal-grained structures for superior combination of mechanical properties.
基金primarily supported by The Natural Science Foundation of China under Grant Nos.51922048,51871108,51625402 and 51671093Partial financial support came from the Fundamental Research Funds for the Central Universities,JLU,Program for JLU Science and Technology Innovative Research Team(JLUSTIRT,2017TD-09)The Changjiang Scholars Program(T2017035)。
文摘Grain boundary strengthening is an effective strategy for increasing mechanical properties of Mg alloys.However,this method offers limited strengthening in bimodal grain-structured Mg alloys due to the difficultly in increasing the volume fraction of fine grains while keeping a small grain size.Herein,we show that the volume fraction of fine grains(FGs,~2.5μm)in the bimodal grain structure can be tailored from~30 vol.%in Mg-9 Al-1 Zn(AZ91)to~52 vol.%in AZ91-1Y(wt.%)processed by hard plate rolling(HPR).Moreover,a superior combination of a high ultimate tensile strength(~405 MPa)and decent uniform elongation(~9%)is achieved in present AZ91-1Y alloy.It reveals that a desired bimodal grain structure can be tailored by the co-regulating effect from coarse Al_(2)Y particles resulting in inhomogeneous recrystallization,and dispersed submicron Mg_(17)Al_(12)particles depressing the growth of recrystallized grains.The findings offer a valuable insight in tailoring bimodal grain-structured Mg alloys for optimized strength and ductility.
