Silicon-air batteries(SABs),a new type of semiconductor air battery,have a high energy density.However,some side reactions in SABs cause Si anodes to be covered by a passivation layer to prevent continuous discharge,a...Silicon-air batteries(SABs),a new type of semiconductor air battery,have a high energy density.However,some side reactions in SABs cause Si anodes to be covered by a passivation layer to prevent continuous discharge,and the anode utilization rate is low.In this work,reduced graphene oxide(RGO)fabricated via high-temperature annealing or L-ascorbic acid(L.AA)reduction was first used to obtain Si nanowires/RGO-1000(Si NWs/RGO-1000)and Si nanowires/RGO-L.AA(Si NWs/RGO-L.AA)composite anodes for SABs.It was found that RGO suppressed the passivation and self-corrosion reactions and that SABs using Si NWs/RGO-L.AA as the anode can discharge for more than 700 h,breaking the previous performance of SABs,and that the specific capacity was increased by 90.8%compared to bare Si.This work provides a new solution for the design of high specific capacity SABs with nanostructures and anode protective layers.展开更多
The electrochemical behaviors and coupling behaviors of the Mg2Si and Si phases with α（Al） were investigated, the corrosion morphologies of Al alloys containing Mg2Si and Si particles were observed, and the corrosi...The electrochemical behaviors and coupling behaviors of the Mg2Si and Si phases with α（Al） were investigated, the corrosion morphologies of Al alloys containing Mg2Si and Si particles were observed, and the corrosion mechanism associated with them in Al-Mg-Si alloys was advanced. The results show that Si particle is always cathodic to the alloy base, Mg2Si is anodic to the alloy base and corrosion occurs on its surface at the beginning. However, during its corrosion process, the preferential dissolution of Mg and the enrichment of Si make Mg2Si transform to cathode from anode, leading to the anodic dissolution and corrosion of the alloy base at its adjacent periphery at a later stage. As the mole ratio of Mg to Si in an Al-Mg-Si alloy is less than 1.73, it contains Mg2Si and Si particles simultaneously in the grain boundary area, and corrosion initiates on the Mg2Si surface and the precipitate-free zone （PFZ） at the adjacent periphery of Si particle. As corrosion time is extended, Si particle leads to severe anodic dissolution and corrosion of the PFZ at its adjacent periphery, expedites the polarity transformation between Mg2Si and the PFZ and accelerates the corrosion of PFZ at the adjacent periphery of Mg2Si particle.展开更多
Solid-state lithium-ion batteries(SSLIBs) offer significant advantages over traditional liquid-electrolytebased batteries,including improved safety,higher energy density,and better thermal stability.Among various anod...Solid-state lithium-ion batteries(SSLIBs) offer significant advantages over traditional liquid-electrolytebased batteries,including improved safety,higher energy density,and better thermal stability.Among various anode materials,silicon(Si)-based anodes have attracted significant attention due to their ultrahigh theoretical capacity(~4200 mAh/g) and abundant resources.However,widespread adoption of Si-based anodes in SSLIBs is still restricted by some critical challenges such as severe volume expansion,low electronic and ionic conductivity,high interfacial impedance,and low initial Coulombic efficiency(ICE).This review mainly focuses on the design strategies of Si-based anode for SSLIBs at the material,electrode and cell levels including nanostructuring,Si alloys,Si-carbon composites,conductive additives,advanced binder,external pressure,electrolyte infiltration,and prelithiation.The insights provided here aim to inspire future research and accelerate commercialization of high-performance Si-based anodes in next-generation SSLIBs.展开更多
A combination of casting and laser remelting was employed to develop a high-strength and heat-resistant Al-Si-Fe alloy suitable for powder bed fusion using a laser beam(PBF-LB).By clarifying the effects of the incorpo...A combination of casting and laser remelting was employed to develop a high-strength and heat-resistant Al-Si-Fe alloy suitable for powder bed fusion using a laser beam(PBF-LB).By clarifying the effects of the incorporated elements and their contents on the microstructure and mechanical performance of Al-Si-Fe alloys,the composition was optimized as Al-11Si-2.5Fe-2Mn-1.2Ni-0.4Cr(in wt.%).The optimized alloy was subsequently validated using PBF-LB,which exhibited favorable machinability,achieving a density of 99.8%.The room-temperature tensile strength of the PBF-LB manufactured Al-Si-Fe alloy reached(512.76±3.26)MPa,with a yield strength of(337.79±2.36)MPa and an elongation of(2.98±0.07)%.The enhanced room-temperature mechanical properties could be mainly attributed to the combined effects of fine-grain strengthening,solid solution strengthening,and precipitation strengthening.At 300°C,the high-temperature tensile strength of the developed alloy reached(222.47±6.41)MPa,with a yield strength of(164.25±11.40)MPa and an elongation of(8.88±0.33)%,outperforming those of existing alloys documented in the literature.The improved high-temperature mechanical performance was primarily provided by the three-dimensional network comprising cellular heat-resistant Al17(FeMnNiCr)4Si2 andα-Al(FeMn)Si phases.展开更多
To improve the wettability of hypereutectic Al−60Si alloy and enhance the mechanical properties of the joints,Al−60Si alloy was joined by ultrasonic soldering with Sn-9Zn solder,and a sound joint with in-situ Si parti...To improve the wettability of hypereutectic Al−60Si alloy and enhance the mechanical properties of the joints,Al−60Si alloy was joined by ultrasonic soldering with Sn-9Zn solder,and a sound joint with in-situ Si particle reinforcement was obtained.The oxide film of Al−60Si alloy at the interface was identified by transmission electron microscopy(TEM)analysis as amorphous Al_(2)O_(3).The oxide of Si particles in the base metal was also alumina.The oxide film of Al−60Si alloy was observed to be removed by ultrasonic vibration instead of holding treatment.Si particle-reinforced joints(35.7 vol.%)were obtained by increasing the ultrasonication time.The maximum shear strength peaked at 99.5 MPa for soldering at 330℃with an ultrasonic vibration time of 50 s.A model of forming of Si particles reinforced joint under the ultrasound was proposed,and ultrasonic vibration was considered to promote the dissolution of Al and migration of Si particles.展开更多
The study aims to investigate the carbonated water erosion mechanism of lining concrete in tunnels traversing karst environment and enhance its resistance.In this study,dynamic carbonated water erosion was simulated t...The study aims to investigate the carbonated water erosion mechanism of lining concrete in tunnels traversing karst environment and enhance its resistance.In this study,dynamic carbonated water erosion was simulated to assess erosion depth,microstructure,phase migrations,and pore structure in various tunnel lining cement-based materials.Additionally,Ca^(2+)leaching was analyzed,and impact of Ca/Si molar ratio in hydration products on erosion resistance was discussed by thermodynamic calculations.The results indicate that carbonated water erosion caused rough and porous surface on specimens,with reduced portlandite and CaCO_(3) content,increased porosity,and an enlargement of pore size.The thermodynamic calculations indicate that the erosion is spontaneous,driven by physical dissolution and chemical reactions dominated by Gibbs free energy.And the erosion reactions proceed more spontaneously and extensively when Ca/Si molar ratio in hydration products was higher.Therefore,cement-based materials with higher portlandite content exhibit weaker erosion resistance.Model-building concrete,with C-S-H gel and portlandite as primary hydration products,has greater erosion susceptibility than shotcrete with ettringite as main hydration product.Moreover,adding silicon-rich mineral admixtures can enhance the erosion resistance.This research offers theory and tech insights to boost cement-based material resistance against carbonated water erosion in karst tunnel engineering.展开更多
To study the influence of silicon(Si)on 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20),NC/CL-20 composite explosives and Si/NC/CL-20 composite explosives were prepared by the electrostatic spraying ...To study the influence of silicon(Si)on 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20),NC/CL-20 composite explosives and Si/NC/CL-20 composite explosives were prepared by the electrostatic spraying method.The morphology,structure and thermal decomposition properties of the samples were analyzed using scanning electron microscopy(SEM),X-ray energy spectroscopy(EDS),infrared spectroscopy(FT-IR),and simultaneous thermal analyzer(TG-DSC).Additionally,the combustion process of the samples was tested using a high-speed camera.The results show that the addition of nano-Si contributes to the formation of composite explosives with regular morphology and smaller particle size.The Si/NC/CL-20 composite explosive has better and more uniform sphericity,with an average particle size of 73.4 nm,compared to the NC/CL-20 composite explosive.The Si/NC/CL-20 composite explosive which produced by the electrostatic spraying method,achieves physically uniform distribution of the components including NC,CL-20,Si.The addition of Si promotes the thermal decomposition of CL-20.In comparison to the NC/CL-20 composite explosive,the activation energy of the Si/NC/CL-20 composite explosive decreases by 16.78 kJ/mol,and the self-accelerated decomposition temperature and the critical temperature of thermal explosion decreases by 3.12 K and 2.61 K,respectively.Furthermore,Si/NC/CL-20 composite explosive has shorter ignition delay time and faster combustion rate compared to the NC/CL-20 composite explosive,which shows that Si can improve the combustion performance of CL-20.展开更多
通过扫描电镜/能谱、X射线衍射以及金相分析,针对含0.3%Fe(质量分数)的Al Mg Si Cu铝合金,研究了Mn含量对其结晶相的影响。研究表明:合金在铸造过程中形成的结晶相为Al1.9CuMg4.1Si3.3,Al5(FeMn)Si,Al8(FeMn)2Si以及少量的Mg2Si;增大含M...通过扫描电镜/能谱、X射线衍射以及金相分析,针对含0.3%Fe(质量分数)的Al Mg Si Cu铝合金,研究了Mn含量对其结晶相的影响。研究表明:合金在铸造过程中形成的结晶相为Al1.9CuMg4.1Si3.3,Al5(FeMn)Si,Al8(FeMn)2Si以及少量的Mg2Si;增大含Mn量,合金中AlFeMnSi型结晶相数量增多;对合金进行均匀化处理时,Al1.9CuMg4.1Si3.3相完全溶解,发生Al5(FeMn)Si向Al8(FeMn)2Si相的转变;对合金进行轧制及最终热处理后,结晶相碎化且沿轧向呈纤维状分布,但结晶相的类型不变。展开更多
The FeNi coated LaFe_(11.6)Si_(1.4)/Sn composites were prepared by hot pressing(HP). The microstructure,corrosion behavior and magnetocaloric effect(MCE) of FeNi coated LaFe_(11.6)Si_(1.4)/Sn composites were investiga...The FeNi coated LaFe_(11.6)Si_(1.4)/Sn composites were prepared by hot pressing(HP). The microstructure,corrosion behavior and magnetocaloric effect(MCE) of FeNi coated LaFe_(11.6)Si_(1.4)/Sn composites were investigated systematically. The results show that the corrosion resistance of FeNi coated LaFe_(11.6)Si_(1.4)Sn composites is better than that of LaFe_(11.6)Si_(1.4)/Sn composites in deionized water. The maximum magnetic entropy change((-△S_M)^(max)) and relative cooling power(RCP) of FeNi coated LaFe_(11.6)Si_(1.4)/Sn composites are 13.30 J/(kg-K) and 146.25 J/kg, respectively, which are larger than that((-△S_M)^(max), 10.65 J/(kg·K) and RCP, 106.53 J/kg) of LaFe_(11.6)Si_(1.4)/Sn composites in a low magnetic field change of 2 T. FeNi coated LaFe_(11.6)Si_(1.4)/Sn composites possess a more negative slope. The improvement of magnetic properties is due to high permeability FeNi permalloy(1 J85) which improves the itinerant-electron metamagnetic(IEM) transition. So, the method of coating FeNi can provide a new idea for enhancing the corrosion resistance and magnetocaloric effect of La(Fe_xSi_(1-x))_(13)-based materials.展开更多
Silicon(Si)is an important element in aquatic ecosystems.Based on the observed data in the Huanghe(Yellow)River Basin,a forward model was used to evaluate the silicate weathering rate in the Huanghe River Basin.The ef...Silicon(Si)is an important element in aquatic ecosystems.Based on the observed data in the Huanghe(Yellow)River Basin,a forward model was used to evaluate the silicate weathering rate in the Huanghe River Basin.The effects of silicate weathering,damming,and land use change on the Si concentration and flux were analyzed.Results show that the dissolved Si(DSi)concentration decreased first and then increased,and was 0.82–2.96 mg/L.As a silicon source in the Huanghe River Basin,the silicate weathering rate in the upper reaches of Lanzhou was high,and a large amount of DSi was transported to the lower reaches.Agricultural irrigation in the middle reaches caused a large amount of DSi loss,and the interception of large-scale cascade reservoirs caused a large amount of DSi retention.The DSi released by sediment re-suspension due to high runoff scouring in the downstream channel also served as a silicon source to supplement the DSi flux transported to the sea.Suspended particulate matter and biogenic Si(BSi)increased first and then decreased in the ranges of 24.1–1590.7 mg/L and 0.08–2.17 mg/L,respectively,due mainly to severe soil erosion in the eastern Loess Plateau,which caused significant amounts of phytoliths to enter the water.展开更多
The effect of Mg/Si mass ratio on the microstructure and mechanical properties of Al-Mg-Si cast aluminum alloys under sub-rapid solidification conditions was investigated.This study utilized four different Mg/Si ratio...The effect of Mg/Si mass ratio on the microstructure and mechanical properties of Al-Mg-Si cast aluminum alloys under sub-rapid solidification conditions was investigated.This study utilized four different Mg/Si ratios:2.83,1.91,1.73,and 1.53.To analyze the evolution of the microstructure,particularly the second phase,various techniques were employed:optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectrometry(EDS),and electron backscatter diffraction(EBSD).Additionally,thermodynamic calculations were performed using the Thermal-calc software to further understand the microstructural changes.Results show that as the Mg/Si ratio decreases from 2.83 to 1.53,α-Al grains become more uniformly distributed.Meanwhile,the morphology of the Mg_(2)Si phases changes from skeletal to short stick shapes with a decreasing aspect ratio.An as-cast Al-Mg-Si alloy with a Mg/Si ratio of 1.53 exhibits high strength,achieving an ultimate tensile strength(UTS)of 320.6 MPa and a yield strength(YS)of 249.9 MPa.The cast alloy with a Mg/Si ratio of 2.83exhibits the highest elongation,reaching 5.31%.This superior elongation is attributed to the uniform distribution of Mg_(2)Si phases,which possess a long skeletal shape.Conversely,the alloy with a Mg/Si ratio of 1.53 demonstrates the lowest elongation,primarily due to the central concentration of Mg_(2)Si phases,which are characterized by their short stick shapes.展开更多
基金supported by the National Natural Science Foundation of China(No.61904073)Spring City Plan-Special Program for Young Talents(No.K202005007)+4 种基金Yunnan Talents Support Plan for Yong Talents(No.XDYC-QNRC-20220482)Yunnan Local Colleges Applied Basic Research Projects(No.202101BA070001-138)Scientific Research Fund of Yunnan Education Department(No.2023Y0883)Frontier Research Team of Kunming University 2023Key Laboratory of Artificial Microstructures in Yunnan Higher Education。
文摘Silicon-air batteries(SABs),a new type of semiconductor air battery,have a high energy density.However,some side reactions in SABs cause Si anodes to be covered by a passivation layer to prevent continuous discharge,and the anode utilization rate is low.In this work,reduced graphene oxide(RGO)fabricated via high-temperature annealing or L-ascorbic acid(L.AA)reduction was first used to obtain Si nanowires/RGO-1000(Si NWs/RGO-1000)and Si nanowires/RGO-L.AA(Si NWs/RGO-L.AA)composite anodes for SABs.It was found that RGO suppressed the passivation and self-corrosion reactions and that SABs using Si NWs/RGO-L.AA as the anode can discharge for more than 700 h,breaking the previous performance of SABs,and that the specific capacity was increased by 90.8%compared to bare Si.This work provides a new solution for the design of high specific capacity SABs with nanostructures and anode protective layers.
基金Project (21073162) supported by the National Natural Science Foundation of ChinaProject (2008) supported by the Scientific and Technological Projects of Ningxia, China+1 种基金Project (08JC1421600) supported by the Science and Technology Commission of Shanghai Municipality, ChinaProject (2008AZ2018) supported by the Science and Technology Bureau of Jiaxing City, China
文摘The electrochemical behaviors and coupling behaviors of the Mg2Si and Si phases with α（Al） were investigated, the corrosion morphologies of Al alloys containing Mg2Si and Si particles were observed, and the corrosion mechanism associated with them in Al-Mg-Si alloys was advanced. The results show that Si particle is always cathodic to the alloy base, Mg2Si is anodic to the alloy base and corrosion occurs on its surface at the beginning. However, during its corrosion process, the preferential dissolution of Mg and the enrichment of Si make Mg2Si transform to cathode from anode, leading to the anodic dissolution and corrosion of the alloy base at its adjacent periphery at a later stage. As the mole ratio of Mg to Si in an Al-Mg-Si alloy is less than 1.73, it contains Mg2Si and Si particles simultaneously in the grain boundary area, and corrosion initiates on the Mg2Si surface and the precipitate-free zone （PFZ） at the adjacent periphery of Si particle. As corrosion time is extended, Si particle leads to severe anodic dissolution and corrosion of the PFZ at its adjacent periphery, expedites the polarity transformation between Mg2Si and the PFZ and accelerates the corrosion of PFZ at the adjacent periphery of Mg2Si particle.
基金financially supported by the National Natural Science Foundation of China(Nos.22366032,52072119)Hunan Intelligent Rehabilitation Robot and Auxiliary Equipment Engineering Technology Research Center(No.2025SH301)。
文摘Solid-state lithium-ion batteries(SSLIBs) offer significant advantages over traditional liquid-electrolytebased batteries,including improved safety,higher energy density,and better thermal stability.Among various anode materials,silicon(Si)-based anodes have attracted significant attention due to their ultrahigh theoretical capacity(~4200 mAh/g) and abundant resources.However,widespread adoption of Si-based anodes in SSLIBs is still restricted by some critical challenges such as severe volume expansion,low electronic and ionic conductivity,high interfacial impedance,and low initial Coulombic efficiency(ICE).This review mainly focuses on the design strategies of Si-based anode for SSLIBs at the material,electrode and cell levels including nanostructuring,Si alloys,Si-carbon composites,conductive additives,advanced binder,external pressure,electrolyte infiltration,and prelithiation.The insights provided here aim to inspire future research and accelerate commercialization of high-performance Si-based anodes in next-generation SSLIBs.
基金supported by the National Natural Science Foundation of China(Nos.52375393,52071299)the Science and Technology Innovation Talent Team of Shanxi Province,China(No.202304051001029)+3 种基金the Scientific and Technological Achievements Transformation Guidance Project of Shanxi Province,China(No.202204021301048)the Key R&D Program of Shanxi Province,China(Nos.2210300058MZ,202202150401020)the Hai’an&Taiyuan University of Technology Advanced Manufacturing and Intelligent Equipment Industrial Research Institute,China(No.2023HA-TYUTKFYF020)the Young Elite Scientists Sponsorship Program by CAST,China(No.2023QNRC001).
文摘A combination of casting and laser remelting was employed to develop a high-strength and heat-resistant Al-Si-Fe alloy suitable for powder bed fusion using a laser beam(PBF-LB).By clarifying the effects of the incorporated elements and their contents on the microstructure and mechanical performance of Al-Si-Fe alloys,the composition was optimized as Al-11Si-2.5Fe-2Mn-1.2Ni-0.4Cr(in wt.%).The optimized alloy was subsequently validated using PBF-LB,which exhibited favorable machinability,achieving a density of 99.8%.The room-temperature tensile strength of the PBF-LB manufactured Al-Si-Fe alloy reached(512.76±3.26)MPa,with a yield strength of(337.79±2.36)MPa and an elongation of(2.98±0.07)%.The enhanced room-temperature mechanical properties could be mainly attributed to the combined effects of fine-grain strengthening,solid solution strengthening,and precipitation strengthening.At 300°C,the high-temperature tensile strength of the developed alloy reached(222.47±6.41)MPa,with a yield strength of(164.25±11.40)MPa and an elongation of(8.88±0.33)%,outperforming those of existing alloys documented in the literature.The improved high-temperature mechanical performance was primarily provided by the three-dimensional network comprising cellular heat-resistant Al17(FeMnNiCr)4Si2 andα-Al(FeMn)Si phases.
基金financial support from the National Natural Science Foundation of China(Nos.52275385,U2167216)Sichuan Province Science and Technology Support Program,China(No.2022YFG0086).
文摘To improve the wettability of hypereutectic Al−60Si alloy and enhance the mechanical properties of the joints,Al−60Si alloy was joined by ultrasonic soldering with Sn-9Zn solder,and a sound joint with in-situ Si particle reinforcement was obtained.The oxide film of Al−60Si alloy at the interface was identified by transmission electron microscopy(TEM)analysis as amorphous Al_(2)O_(3).The oxide of Si particles in the base metal was also alumina.The oxide film of Al−60Si alloy was observed to be removed by ultrasonic vibration instead of holding treatment.Si particle-reinforced joints(35.7 vol.%)were obtained by increasing the ultrasonication time.The maximum shear strength peaked at 99.5 MPa for soldering at 330℃with an ultrasonic vibration time of 50 s.A model of forming of Si particles reinforced joint under the ultrasound was proposed,and ultrasonic vibration was considered to promote the dissolution of Al and migration of Si particles.
基金Project(2021YJ059)supported by the Research Project of China Academy of Railway Sciences。
文摘The study aims to investigate the carbonated water erosion mechanism of lining concrete in tunnels traversing karst environment and enhance its resistance.In this study,dynamic carbonated water erosion was simulated to assess erosion depth,microstructure,phase migrations,and pore structure in various tunnel lining cement-based materials.Additionally,Ca^(2+)leaching was analyzed,and impact of Ca/Si molar ratio in hydration products on erosion resistance was discussed by thermodynamic calculations.The results indicate that carbonated water erosion caused rough and porous surface on specimens,with reduced portlandite and CaCO_(3) content,increased porosity,and an enlargement of pore size.The thermodynamic calculations indicate that the erosion is spontaneous,driven by physical dissolution and chemical reactions dominated by Gibbs free energy.And the erosion reactions proceed more spontaneously and extensively when Ca/Si molar ratio in hydration products was higher.Therefore,cement-based materials with higher portlandite content exhibit weaker erosion resistance.Model-building concrete,with C-S-H gel and portlandite as primary hydration products,has greater erosion susceptibility than shotcrete with ettringite as main hydration product.Moreover,adding silicon-rich mineral admixtures can enhance the erosion resistance.This research offers theory and tech insights to boost cement-based material resistance against carbonated water erosion in karst tunnel engineering.
基金National Natural Science Foundation of China(No.22275150)。
文摘To study the influence of silicon(Si)on 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20),NC/CL-20 composite explosives and Si/NC/CL-20 composite explosives were prepared by the electrostatic spraying method.The morphology,structure and thermal decomposition properties of the samples were analyzed using scanning electron microscopy(SEM),X-ray energy spectroscopy(EDS),infrared spectroscopy(FT-IR),and simultaneous thermal analyzer(TG-DSC).Additionally,the combustion process of the samples was tested using a high-speed camera.The results show that the addition of nano-Si contributes to the formation of composite explosives with regular morphology and smaller particle size.The Si/NC/CL-20 composite explosive has better and more uniform sphericity,with an average particle size of 73.4 nm,compared to the NC/CL-20 composite explosive.The Si/NC/CL-20 composite explosive which produced by the electrostatic spraying method,achieves physically uniform distribution of the components including NC,CL-20,Si.The addition of Si promotes the thermal decomposition of CL-20.In comparison to the NC/CL-20 composite explosive,the activation energy of the Si/NC/CL-20 composite explosive decreases by 16.78 kJ/mol,and the self-accelerated decomposition temperature and the critical temperature of thermal explosion decreases by 3.12 K and 2.61 K,respectively.Furthermore,Si/NC/CL-20 composite explosive has shorter ignition delay time and faster combustion rate compared to the NC/CL-20 composite explosive,which shows that Si can improve the combustion performance of CL-20.
文摘通过扫描电镜/能谱、X射线衍射以及金相分析,针对含0.3%Fe(质量分数)的Al Mg Si Cu铝合金,研究了Mn含量对其结晶相的影响。研究表明:合金在铸造过程中形成的结晶相为Al1.9CuMg4.1Si3.3,Al5(FeMn)Si,Al8(FeMn)2Si以及少量的Mg2Si;增大含Mn量,合金中AlFeMnSi型结晶相数量增多;对合金进行均匀化处理时,Al1.9CuMg4.1Si3.3相完全溶解,发生Al5(FeMn)Si向Al8(FeMn)2Si相的转变;对合金进行轧制及最终热处理后,结晶相碎化且沿轧向呈纤维状分布,但结晶相的类型不变。
基金Project supported by the Key Project of National Natural Science Foundation of China(51176065)
文摘The FeNi coated LaFe_(11.6)Si_(1.4)/Sn composites were prepared by hot pressing(HP). The microstructure,corrosion behavior and magnetocaloric effect(MCE) of FeNi coated LaFe_(11.6)Si_(1.4)/Sn composites were investigated systematically. The results show that the corrosion resistance of FeNi coated LaFe_(11.6)Si_(1.4)Sn composites is better than that of LaFe_(11.6)Si_(1.4)/Sn composites in deionized water. The maximum magnetic entropy change((-△S_M)^(max)) and relative cooling power(RCP) of FeNi coated LaFe_(11.6)Si_(1.4)/Sn composites are 13.30 J/(kg-K) and 146.25 J/kg, respectively, which are larger than that((-△S_M)^(max), 10.65 J/(kg·K) and RCP, 106.53 J/kg) of LaFe_(11.6)Si_(1.4)/Sn composites in a low magnetic field change of 2 T. FeNi coated LaFe_(11.6)Si_(1.4)/Sn composites possess a more negative slope. The improvement of magnetic properties is due to high permeability FeNi permalloy(1 J85) which improves the itinerant-electron metamagnetic(IEM) transition. So, the method of coating FeNi can provide a new idea for enhancing the corrosion resistance and magnetocaloric effect of La(Fe_xSi_(1-x))_(13)-based materials.
基金Supported by the Joint Fund of National Natural Science Foundation of China(NSFC)and Shandong Province(Nos.U22A20580,U1906210)the Laoshan Laboratory(No.LSKJ202203904)the National Natural Science Foundation of China(No.41876116)。
文摘Silicon(Si)is an important element in aquatic ecosystems.Based on the observed data in the Huanghe(Yellow)River Basin,a forward model was used to evaluate the silicate weathering rate in the Huanghe River Basin.The effects of silicate weathering,damming,and land use change on the Si concentration and flux were analyzed.Results show that the dissolved Si(DSi)concentration decreased first and then increased,and was 0.82–2.96 mg/L.As a silicon source in the Huanghe River Basin,the silicate weathering rate in the upper reaches of Lanzhou was high,and a large amount of DSi was transported to the lower reaches.Agricultural irrigation in the middle reaches caused a large amount of DSi loss,and the interception of large-scale cascade reservoirs caused a large amount of DSi retention.The DSi released by sediment re-suspension due to high runoff scouring in the downstream channel also served as a silicon source to supplement the DSi flux transported to the sea.Suspended particulate matter and biogenic Si(BSi)increased first and then decreased in the ranges of 24.1–1590.7 mg/L and 0.08–2.17 mg/L,respectively,due mainly to severe soil erosion in the eastern Loess Plateau,which caused significant amounts of phytoliths to enter the water.
基金supported by the WQ&UCS (Binzhou)Industrialization Research Institute。
文摘The effect of Mg/Si mass ratio on the microstructure and mechanical properties of Al-Mg-Si cast aluminum alloys under sub-rapid solidification conditions was investigated.This study utilized four different Mg/Si ratios:2.83,1.91,1.73,and 1.53.To analyze the evolution of the microstructure,particularly the second phase,various techniques were employed:optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectrometry(EDS),and electron backscatter diffraction(EBSD).Additionally,thermodynamic calculations were performed using the Thermal-calc software to further understand the microstructural changes.Results show that as the Mg/Si ratio decreases from 2.83 to 1.53,α-Al grains become more uniformly distributed.Meanwhile,the morphology of the Mg_(2)Si phases changes from skeletal to short stick shapes with a decreasing aspect ratio.An as-cast Al-Mg-Si alloy with a Mg/Si ratio of 1.53 exhibits high strength,achieving an ultimate tensile strength(UTS)of 320.6 MPa and a yield strength(YS)of 249.9 MPa.The cast alloy with a Mg/Si ratio of 2.83exhibits the highest elongation,reaching 5.31%.This superior elongation is attributed to the uniform distribution of Mg_(2)Si phases,which possess a long skeletal shape.Conversely,the alloy with a Mg/Si ratio of 1.53 demonstrates the lowest elongation,primarily due to the central concentration of Mg_(2)Si phases,which are characterized by their short stick shapes.
