Rotating machinery in the aviation industry is increasingly embracing high speeds and miniaturization,and foil dynamic pressure gas bearing has great application value due to its self-lubrication and self-adaptive def...Rotating machinery in the aviation industry is increasingly embracing high speeds and miniaturization,and foil dynamic pressure gas bearing has great application value due to its self-lubrication and self-adaptive deformation characteristics.This study explores the interaction mechanism between micro-scale variable-sectional shearing flow with hyper-rotation speeds and a three-layer elastic foil assembly through bidirectional aero-elastic coupling in a Multi-layer Thrust Gas Foil Bearing(MTGFB).The bearing capacity of the MTGFB varies non-linearly with the decrease of gas film clearance,while the collaborative deformation of the three-layer elastic foil assembly can deal with different load conditions.As the load capacity increases,the enhanced dynamic pressure effect causes the top foil to evolve from a single arch to multiple arches.The hydrodynamic effects in the gas film evolve to form multiple segmented wedges with different pitch ratios,while the peak pressure of the gas film always occurs near the vaults of the top foil.As the rotational speed frequency approaches the natural frequency,the resonance of the gas film and elastic foil assembly system occurs,and a phase delay occurs between the pressure pulsation and the vibration of foils.The load capacity of the MTGFB also depends on the elastic moduli of the elastic foil assembly.Increasing the elastic modulus decreases the deformation amplitude of the top foil,whereas it increases those of the backboard and middle foil,increasing the load capacity.展开更多
Based on the microstructure characterization,electrochemical impedance spectroscopy,potentiodynamic polarization,and immersion corrosion,this work comparatively analyzed the differences in the electrochemical corrosio...Based on the microstructure characterization,electrochemical impedance spectroscopy,potentiodynamic polarization,and immersion corrosion,this work comparatively analyzed the differences in the electrochemical corrosion morphology and post-foil formation surface morphology of laser beam welded(LBW)sample and spin-formed sample,and compared the corrosion resistance and Cu foil formation ability of two samples in H_(2)SO_(4)/NaCl solution and CuSO_(4) reducing electrolyte.Results show that in H_(2)SO_(4) and NaCl solutions,LBW sample and spin-formed sample exhibit excellent passivation ability and corrosion resistance.Both samples show uniform corrosion morphologies and similar corrosion resistance in the strong acidic solution containing Cl^(-).Meanwhile,the Cu foil formation ability of the welded joint is similar to that of the spin-formed sample,and both samples obtain intact Cu foils with high-quality surfaces and small differences in properties.展开更多
Electrolytic copper foil has gained significant attention as an essential component in lithium-ion batteries(LIBs),printed circuit boards(PCBs),and chip packaging substrates(CPSs)applications.With the advancement of L...Electrolytic copper foil has gained significant attention as an essential component in lithium-ion batteries(LIBs),printed circuit boards(PCBs),and chip packaging substrates(CPSs)applications.With the advancement of LIBs towards higher energy densities and the increasing density of electronic components on circuits,copper foil is required to have demanding properties,such as extremely thin thickness and extremely high tensile strength.This comprehensive review firstly summarizes recent progress on the fabrication of electrolytic copper foil,and the effects of process parameters,cathode substrate,and additives on the electrodeposition behavior,microstructure,and properties of copper foil are discussed in detail.Then the regulation strategies of mechanical properties of electrolytic copper foil are also summarized,including the formation of nanotwins and texture.Furthermore,the recent advances in novel electrolytic copper foils,such as composite foils and extra-thin copper foils,are also overviewed.Lastly,the remaining challenges and perspectives on the further development of electrolytic copper foils are presented.展开更多
The effect of rolling schedules on the ridging resistance of ultra-thin ferritic stainless steel(FSS)430 foil was evaluated by studying the microstructure and texture.The results show that specimens processed with thr...The effect of rolling schedules on the ridging resistance of ultra-thin ferritic stainless steel(FSS)430 foil was evaluated by studying the microstructure and texture.The results show that specimens processed with three-pass cold rolling under the reductions of 40%,40%and 31%,respectively,exhibit improved ridging resistance owing to the microstructural refinement and the texture structure optimization.A nearly 40%reduction of ridging height can be achieved using the proposed rolling schedule compared to the other two rolling schedules.In addition,the effect of annealing temperature after cold rolling on the ridging resistance of FSS 430 foil is also found to be crucial,and an optimal annealing temperature of 900℃ is obtained for FSS 430 foil with high ridging resistance.Overall,the improvement in the ridging resistance of FSS 430 foil can be attributed to the reduction in the fraction of{001}<110>and{114}<110>components by optimization of the rolling and annealing processes.展开更多
Stripping injection overcomes the limitations of Liouville's theorem and is widely used for beam injection and accumulation in high-intensity synchrotrons.The interaction between the stripping foil and beam is cru...Stripping injection overcomes the limitations of Liouville's theorem and is widely used for beam injection and accumulation in high-intensity synchrotrons.The interaction between the stripping foil and beam is crucial in the study of stripping injection,particularly in low-energy stripping injection synchrotrons,such as the XiPAF synchrotron.The foil thickness is the main parameter that affects the properties of the beam after injection.The thin stripping foil is reinforced with collodion during its installation.However,the collodion on the foil surface makes it difficult to determine its equivalent thickness,because the mechanical measurements are not sufficiently reliable or convenient for continuously determining foil thickness.We propose an online stripping foil thickness measurement method based on the ionization energy loss effect,which is suitable for any foil thickness and does not require additional equipment.Experimental studies were conducted using the XiPAF synchrotron.The limitation of this method was examined,and the results were verified by comparing the experimentally obtained beam current accumulation curves with the simulation results.This confirms the accuracy and reliability of the proposed method for measuring the stripping foil thickness.展开更多
The equimolar NbZrTi medium-entropy alloy(MEA)has attracted attention due to its excellent comprehensive mechanical properties.In this study,the designed body-centered cubic NbZrTiAl_(4)(atomic percent,at%)MEA by Al a...The equimolar NbZrTi medium-entropy alloy(MEA)has attracted attention due to its excellent comprehensive mechanical properties.In this study,the designed body-centered cubic NbZrTiAl_(4)(atomic percent,at%)MEA by Al addition,having a superplastic extensibility of~5000%under cold rolling,enables directly fabricated ultrathin foils with a thickness down to~0.2 mm without any treatments.Particularly,the annealed NbZrTiAl_(4) MEA foils,containing a coherent nanoscale B2,exhibit an ultrahigh yield strength of up to~1130 MPa,which even surpasses the bulk counterpart,while maintaining a good fracture elongation of up to~14%.The Al addition induced a stronger solid solution strengthening and fine-grain strengthening in the foils.Complex dislocation interactions and dislocation–B2 interactions promoted a dynamical formation of dislocation bands,which yielded work-hardening ability and tensile ductility.These findings provide a novel strategy for the design of ultrathin refractory medium-entropy foils to break through their performance limits at ultrahigh temperatures and guide the design of high-performance lightweight foils for structural applications.展开更多
The edge crack behavior of copper foil in asymmetrical micro-rolling was studied.The effects of the speed ratio between rolls,grain size and stress state in the deformation zone on edge cracks of the rolled piece in a...The edge crack behavior of copper foil in asymmetrical micro-rolling was studied.The effects of the speed ratio between rolls,grain size and stress state in the deformation zone on edge cracks of the rolled piece in asymmetrical rolling were analyzed.Low plasticity,uneven deformation and longitudinal secondary tensile stress generated in the edge area of the rolled piece during the rolling process are the main causes of edge cracks.The larger the grain size of the rolled piece,the smaller the number of edge cracks and the deeper the expansion depth,and the larger the spacing between cracks under the same rolling reduction.Asymmetrical rolling can effectively increase the rolling reduction at when the copper foil fist shows edge cracks compared to symmetrical rolling.This enhancement is attributed to the shearing stress induced by asymmetrical rolling,which reduces the rolling force and longitudinal secondary tensile stress,and increases the residual compressive stress on the surface of the rolled piece.The edge crack defects of copper foil can be effectively reduced by increasing the speed ratio between the rolls in asymmetrical rolling.展开更多
In order to gain a deeper understanding of the effect of pulsed current on the mechanical properties and size effect of nanocrystalline Ni foils,nanocrystalline Ni foils with different grain thickness-to-grain size ra...In order to gain a deeper understanding of the effect of pulsed current on the mechanical properties and size effect of nanocrystalline Ni foils,nanocrystalline Ni foils with different grain thickness-to-grain size ratios(λ)were prepared using pulsed electrodeposition in this paper and unidirectional tensile experiments were carried out at room temperature with different currents and their applied directions.The experimental results show that the nanocrystalline Ni foil produces an obvious electroplasticity effect after applying the current field,and when 300<λ<1100,the current weakens the size effect of nanocrystalline Ni foils to a certain extent,and the angle between the current direction and the deformation direction also affects the mechanical response of nanocrystalline Ni foils,and when the angle between the current direction and the deformation direction is 0°,electroplasticity effect is the best,and the current has the most significant effect of abating the size effect of the material.The mechanism of unidirectional tensile deformation of nanocrystalline Ni foils under the effect of pulsed current was analyzed using TEM and TKD.It was found that the applied pulse current increased the activity of the nanocrystalline boundaries,promoted the movement of dislocations,and reduced the tendency of dislocation entanglement.The higher the peak current density and the smaller the angle between the direction of the current and the direction of deformation,the smaller the grain boundary orientation difference,the more dispersed the grain orientation,and the lower the density of geometrically necessary dislocations(GND)in the deformed nanocrystalline foil,the more significant the effect on material plasticity improvement.展开更多
In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The...In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The results show that compared to 100μm thick Ti foil,10μm thick Ti foil is more prone to fracture and is evenly distributed in fragments at the interface.The introduction of Ti foil can effectively refine the grain size of Mg layers of as-rolled Mg/Al composite plates,10μm thick Ti foil has a better refining effect than 100μm thick Ti foil.Ti foil can effectively increase the yield strength(YS)and ultimate strength(UTS)of as-rolled Mg/Al composite plates,10μm thick Ti foil significantly improves the elongation(El)of Mg/Al composite plate,while 100μm thick Ti foil slightly weakens the El.After annealing at 420℃ for 0.5 h and 4 h,Ti foil can inhibit the formation of intermetallic compounds(IMCs)at the interface of Mg/Al composite plates,which effectively improves the YS,UTS and El of Mg/Al composite plates.In addition,Ti foil can also significantly enhance the interfacial shear strength(SS)of Mg/Al composite plates before and after annealing.展开更多
Metal foils have emerged as one of the promising materials for anode-free batteries due to their high energy density and scalability in production.The unclear lithium plating/stripping kinetics of metal foil current c...Metal foils have emerged as one of the promising materials for anode-free batteries due to their high energy density and scalability in production.The unclear lithium plating/stripping kinetics of metal foil current collectors in anode-free batteries was addressed by using the non-destructive distribution of relaxation times(DRT)analysis to systematically investigate the lithium transport behavior of 14 metal foils and its correlation with electrochemical performance.By integrating energy-dispersive spectro scopy(EDS),cyclic voltammetry(CV),and galvanostatic testing,the exceptional properties of indium(In),tin(Sn),and silver(Ag)were revealed:the Li-In alloying reaction exhibits high reversibility,Li-Sn alloys demonstrate outstanding cycling stability,and the Li-Ag solid-solution mechanism provides an ideal lithium deposition interface on the silver substrate.The DRT separates the polarization internal resistance of lithium ions passing through the SEI layer(R_(sei),τ2)and the polarization internal resistance of lithium ions undergoing charge transfer reaction at the electrolyte/electrode interface(R_(ct),τ3)by decoupling the electrochemical impedance spectroscopy(EIS).For the first time,the correlation betweenτ2,τ3,and the cycle life/Coulombic efficiency of alloy/solid-solution metals was established,while non-alloy metals are not suitable for this method due to differences in lithium deposition mechanisms.This study not only illuminates the structure-property relationship governing the lithium kinetics of metal foil electrodes but also provides a novel non-destructive analytical strategy and theoretical guidance for the rational design of stable anodes in high-energy-density batteries,facilitating the efficient screening and optimization of anode-free battery.展开更多
The integration method of exploding foil initiator system(EFIs) used to be researched to broaden its application range in military and aerospace in the last few decades.In order to lower the firing voltage below 1 kV,...The integration method of exploding foil initiator system(EFIs) used to be researched to broaden its application range in military and aerospace in the last few decades.In order to lower the firing voltage below 1 kV,an integrated EFIs with enhanced energy efficiency was designed.Corresponding exploding foil initiator chips were fabricated in batch via micro electromechanical systems technology by integrating a unified foil,a flyer layer and a barrel on a glass substrate successively,meanwhile its package of the whole system was proposed at a volume of 2.194 cm^(3).The structural parameters were determined by predicted performance including flyer velocity,impact behavior and conduction property via the proposed theoretical models and the static electric field simulation.As expect,this integrated EFIs exhibited excellent functions,which could accelerate the flyer to a terminal velocity over 4 km/s and preeminently initiate HNS-IV pellet at a circuit of 0.24 μF/0.9 kV.Furthermore,the theoretical design,fabrication and performance test have been all included to validate the feasibility of this integrated EFIs that was beneficial for its commercial development in the future.展开更多
Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ig...Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ignition mechanism of EFIs directly igniting pyrotechnics.An oscilloscope,a photon Doppler velocimetry,and a plasma spectrum measurement system were employed to obtain information of electric characteristics,impact pressure,and plasma temperature.The results of the electric characteristics and the impact pressure were inconsistent with ignition results.The only thing that the ignition success tests had in common was that their plasma all had a relatively long period of high-temperature duration(HTD).It eventually concludes that the ignition mechanism in this research is the microconvection heat transfer rather than the shock initiation,which differs from that of exploding foil initiators detonating explosives.Furthermore,the methods for evaluating the ignition success of semiconductor bridge initiators are not entirely applicable to the tests mentioned in this paper.The HTD is the critical parameter for judging the ignition success,and it is influenced by two factors:the late time discharge and the energy of the electric explosion.The longer time of the late time discharge and the more energy of the electric explosion,the easier it is to expand the HTD,which improves the probability of the ignition success.展开更多
Magnesium and magnesium alloy foils have great potential for application in battery anodes,electromagnetic shielding,optics and acoustics,and biology because of their excellent specific damping,internal dissipation co...Magnesium and magnesium alloy foils have great potential for application in battery anodes,electromagnetic shielding,optics and acoustics,and biology because of their excellent specific damping,internal dissipation coefficients,magnetic and electrical conductivities,as well as high theoretical specific capacity.However,magnesium alloys exhibit poor deformation ability due to their hexagonal close-packed crystal structure.Preparing magnesium and magnesium alloy foils with thicknesses of less than 0.1 mm is difficult because of surface oxidation and grain growth at high temperatures or severe anisotropy after cold rolling that leads to cracks.Numerous methods have been applied to prepare magnesium alloy foils.They include warm rolling,cold rolling,accumulative roll bonding,electric plastic rolling,and on-line heating rolling.Defects of magnesium and magnesium alloy foils during preparation,such as edge cracks and breakage,are important factors for consideration.Herein,the current status of the research on magnesium and magnesium alloy foils is summarized from the aspects of foil preparation,defect control,performance characterization,and application prospects.The advantages and disadvantages of different preparation methods and defect(edge cracks and breakage)mechanisms in the preparation of foils are identified.展开更多
Depending on the production process,copper(Cu)foils can be classified into two types,i.e.,rolled copper(r-Cu)foils and electrolytic copper(e-Cu)foils.Owing to their high electrical conductivity and ductility at low co...Depending on the production process,copper(Cu)foils can be classified into two types,i.e.,rolled copper(r-Cu)foils and electrolytic copper(e-Cu)foils.Owing to their high electrical conductivity and ductility at low cost,e-Cu foils are employed extensively in modern industries and account for more than 98%of the Cu foil market share.However,industrial e-Cu foils have never been single-crystallized due to their high density of grain boundaries,various grain orientations and vast impurities originating from the electrochemical deposition process.Here,we report a methodology of transforming industrial e-Cu foils into single crystals by facet copy from a single-crystal template.Different facets of both low and high indices are successfully produced,and the thickness of the single crystal can reach 500μm.Crystallographic characterizations directly recognized the single-crystal copy process,confirming the complete assimilation impact from the template.The obtained single-crystal e-Cu foils exhibit remarkably improved ductility(elongation-to-fracture of 105%vs.25%),fatigue performance(the average numbers of cycles to failure of 1600 vs.200)and electrical property(electrical conductivity of 102.6%of the international annealed copper standard(IACS)vs.98.5%)than original ones.This work opens up a new avenue for the preparation of single-crystal e-Cu foils and may expand their applications in high-speed,flexible,and wearable devices.展开更多
Explosion-electricity coupling(EEC) is a technical method to induce electric energy into the plasma material produced by explosion to improve the output of explosion.Exploding foil initiator(EFI) which could produce p...Explosion-electricity coupling(EEC) is a technical method to induce electric energy into the plasma material produced by explosion to improve the output of explosion.Exploding foil initiator(EFI) which could produce plasma during electric explosion can serve as a good carrier for studying the EEC.To investigate the enhancement ability and mechanism of EEC in EFI ignition performance,a kind of EFI chips which could realize the EEC effect was designed and fabricated to observe the characteristics of current and voltage,flyer and plasma temperature during Boron Potassium Nitrate(BPN) ignition of the EFI.It was found that the EEC could enhance EFI ignition in terms of energy utilization,ignition contact surface,and high-temperature sustainability of plasma:firstly,the EEC prolonged the late time discharge(LTD) phase of the electric explosion,making the energy of capacitor effectively utilized;secondly,the EEC could create a larger area of ignition contact surface;last of all,the EEC effect enhanced its hightemperature sustainability by sustaining continuous energy input to plasma.It also was found that the ignition voltage of BPN could be reduced by nearly 600 V under the condition of 0.4 μF capacitance.The research has successfully combined EEC with EFI,revealing the behavioral characteristics of EEC and demonstrating its effective enhancement of EFI ignition.It introduces a new approach to improving EFI output,which is conducive to low-energy ignition of EFI,and expected to take the ignition technology of EFI to a new level.展开更多
High-purity copper(Cu) with excellent thermal and electrical conductivity, is crucial in modern technological applications, including heat exchangers, integrated circuits, and superconducting magnets. The current puri...High-purity copper(Cu) with excellent thermal and electrical conductivity, is crucial in modern technological applications, including heat exchangers, integrated circuits, and superconducting magnets. The current purification process is mainly based on the zone/electrolytic refining or anion exchange, however, which excessively relies on specific integrated equipment with ultra-high vacuum or chemical solution environment, and is also bothered by external contaminants and energy consumption. Here we report a simple approach to purify the Cu foils from 99.9%(3N) to 99.99%(4N) by a temperature-gradient thermal annealing technique, accompanied by the kinetic evolution of single crystallization of Cu.The success of purification mainly relies on(i) the segregation of elements with low effective distribution coefficient driven by grain-boundary movements and(ii) the high-temperature evaporation of elements with high saturated vapor pressure.The purified Cu foils display higher flexibility(elongation of 70%) and electrical conductivity(104% IACS) than that of the original commercial rolled Cu foils(elongation of 10%, electrical conductivity of ~ 100% IACS). Our results provide an effective strategy to optimize the as-produced metal medium, and therefore will facilitate the potential applications of Cu foils in precision electronic products and high-frequency printed circuit boards.展开更多
Al/Ni reactive multilayer foil(RMF)possesses excellent comprehensive properties as a promising substitute for traditional Cu bridge.A theoretical resistivity model of Al/Ni RMF was developed to guide the optimization ...Al/Ni reactive multilayer foil(RMF)possesses excellent comprehensive properties as a promising substitute for traditional Cu bridge.A theoretical resistivity model of Al/Ni RMF was developed to guide the optimization of EFIs.Al/Ni RMF with different bilayer thicknesses and bridge dimensions were prepared by MEMS technology and electrical explosion tests were carried out.According to physical and chemical reactions in bridge,the electrical explosion process was divided into 5 stages:heating of condensed bridge,vaporization and diffusion of Al layers,intermetallic combination reaction,intrinsic explosion,ionization of metal gases,which are obviously shown in measured voltage curve.Effects of interface and grain boundary scattering on the resistivity of film metal were considered.Focusing on variations of substance and state,the resistivity was developed as a function of temperature at each stage.Electrical explosion curves were calculated by this model at different bilayer thicknesses,bridge dimensions and capacitor voltages,which showed an excellent agreement with experimental ones.展开更多
Ultrasonic baths and sonochemical reactors are widely used in industrial applications dealing with surface cleaningand chemical synthesis. The processes of erosion, cleaning and structuring of the surface can be typic...Ultrasonic baths and sonochemical reactors are widely used in industrial applications dealing with surface cleaningand chemical synthesis. The processes of erosion, cleaning and structuring of the surface can be typically controlledby changing relevant influential parameters. In particular, in this work, we experimentally investigate theeffect of NaCl concentration (0–5.5 mol/L) on the erosion of an aluminum foil under ultrasonic exposure at afrequency of 28 kHz. Special attention is paid to the determination of cavitation zones and their visualizationusing heat maps. It is found that at low NaCl concentration (0.3 mol/L), the foil destruction rate is higher thanin distilled water. At higher concentrations of salt, cavitation takes place mainly in the upper part of the container.展开更多
The aluminum foil for high voltage aluminum electrolytic capacitor was immersed in 0.5 mol/L H3PO4 or 0.125 mol/L NaOH solution at 40 ℃ for different time and then DC electro-etched in 1 mol/L HC1＋2.5 mol/L H2SO4 el...The aluminum foil for high voltage aluminum electrolytic capacitor was immersed in 0.5 mol/L H3PO4 or 0.125 mol/L NaOH solution at 40 ℃ for different time and then DC electro-etched in 1 mol/L HC1＋2.5 mol/L H2SO4 electrolyte at 80 ℃. The pitting potential and self corrosion potential of A1 foil were measured with polarization curves （PC）. The potentiostatic current--time curve was recorded and the surface and cross section images of etched A1 foil were observed with SEM. The electrochemical impedance spectroscopy （EIS） of etched A1 foil and potential transient curves （PTC） during initial etching stage were measured. The results show the chemical pretreatments can activate A1 foil surface, facilitate the absorption, diffusion and migration of C1- onto the A1 foil during etching, and improve the initiation rate of meta-stable pits and density of stable pits and tunnels, leading to much increase in the real surface area and special capacitance of etched A1 foil.展开更多
The Al foil for high voltage Al electrolytic capacitor usage was immersed in 5.0%NaOH solution containing trace amount of Zn2＋and Zn was chemically plated on its surface through an immersion-reduction reaction. Such ...The Al foil for high voltage Al electrolytic capacitor usage was immersed in 5.0%NaOH solution containing trace amount of Zn2＋and Zn was chemically plated on its surface through an immersion-reduction reaction. Such Zn-deposited Al foil was quickly transferred into HCl-H 2 SO 4 solution for DC-etching. The effects of Zn impurity on the surface and cross-section etching morphologies and electrochemical behavior of Al foil were investigated by SEM, polarization curve （PC） and electrochemical impedance spectroscopy （EIS）. The special capacitance of 100 V formation voltage of etched foil was measured. The results show that the chemical plating Zn on Al substrate in alkali solution can reduce the pitting corrosion resistance, enhance the pitting current density and improve the density and uniform distribution of pits and tunnels due to formation of the micro Zn-Al galvanic local cells. The special capacitance of etched foil grows with the increase of Zn2＋concentration.展开更多
基金the financial support from the National Natural Science Foundation of China(No.52206091)the Aeronautical Science Foundation of China(No.201928052008)the Natural Science Foundation of Jiangsu Province,China(No.BK20210303)。
文摘Rotating machinery in the aviation industry is increasingly embracing high speeds and miniaturization,and foil dynamic pressure gas bearing has great application value due to its self-lubrication and self-adaptive deformation characteristics.This study explores the interaction mechanism between micro-scale variable-sectional shearing flow with hyper-rotation speeds and a three-layer elastic foil assembly through bidirectional aero-elastic coupling in a Multi-layer Thrust Gas Foil Bearing(MTGFB).The bearing capacity of the MTGFB varies non-linearly with the decrease of gas film clearance,while the collaborative deformation of the three-layer elastic foil assembly can deal with different load conditions.As the load capacity increases,the enhanced dynamic pressure effect causes the top foil to evolve from a single arch to multiple arches.The hydrodynamic effects in the gas film evolve to form multiple segmented wedges with different pitch ratios,while the peak pressure of the gas film always occurs near the vaults of the top foil.As the rotational speed frequency approaches the natural frequency,the resonance of the gas film and elastic foil assembly system occurs,and a phase delay occurs between the pressure pulsation and the vibration of foils.The load capacity of the MTGFB also depends on the elastic moduli of the elastic foil assembly.Increasing the elastic modulus decreases the deformation amplitude of the top foil,whereas it increases those of the backboard and middle foil,increasing the load capacity.
基金Key Research and Development Program of Shaanxi Province(2022GY-410)Funding of Western Titanium Technologies Co.,Ltd(WX2210)。
文摘Based on the microstructure characterization,electrochemical impedance spectroscopy,potentiodynamic polarization,and immersion corrosion,this work comparatively analyzed the differences in the electrochemical corrosion morphology and post-foil formation surface morphology of laser beam welded(LBW)sample and spin-formed sample,and compared the corrosion resistance and Cu foil formation ability of two samples in H_(2)SO_(4)/NaCl solution and CuSO_(4) reducing electrolyte.Results show that in H_(2)SO_(4) and NaCl solutions,LBW sample and spin-formed sample exhibit excellent passivation ability and corrosion resistance.Both samples show uniform corrosion morphologies and similar corrosion resistance in the strong acidic solution containing Cl^(-).Meanwhile,the Cu foil formation ability of the welded joint is similar to that of the spin-formed sample,and both samples obtain intact Cu foils with high-quality surfaces and small differences in properties.
基金supported by the National Key R&D Plan Program of China(No.2021YFB3400800)Henan Key Research and Development Program(No.231111241000)+1 种基金the Joint Fund of Henan Province Science and Technology R&D Program(No.225200810026)Zhongyuan Scholar Workstation Funded Program(No.224400510025).
文摘Electrolytic copper foil has gained significant attention as an essential component in lithium-ion batteries(LIBs),printed circuit boards(PCBs),and chip packaging substrates(CPSs)applications.With the advancement of LIBs towards higher energy densities and the increasing density of electronic components on circuits,copper foil is required to have demanding properties,such as extremely thin thickness and extremely high tensile strength.This comprehensive review firstly summarizes recent progress on the fabrication of electrolytic copper foil,and the effects of process parameters,cathode substrate,and additives on the electrodeposition behavior,microstructure,and properties of copper foil are discussed in detail.Then the regulation strategies of mechanical properties of electrolytic copper foil are also summarized,including the formation of nanotwins and texture.Furthermore,the recent advances in novel electrolytic copper foils,such as composite foils and extra-thin copper foils,are also overviewed.Lastly,the remaining challenges and perspectives on the further development of electrolytic copper foils are presented.
基金supported by the National Natural Science Foundation of China(Nos.52105392 and 52275359)the Central Government Guided Local Science and Technology Development Fund Project(Grant No.YDZJSX2021A006)+1 种基金the Natural Foundation of Shanxi Province(Grant No.20210302123166)the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province(Grant No.20210035).
文摘The effect of rolling schedules on the ridging resistance of ultra-thin ferritic stainless steel(FSS)430 foil was evaluated by studying the microstructure and texture.The results show that specimens processed with three-pass cold rolling under the reductions of 40%,40%and 31%,respectively,exhibit improved ridging resistance owing to the microstructural refinement and the texture structure optimization.A nearly 40%reduction of ridging height can be achieved using the proposed rolling schedule compared to the other two rolling schedules.In addition,the effect of annealing temperature after cold rolling on the ridging resistance of FSS 430 foil is also found to be crucial,and an optimal annealing temperature of 900℃ is obtained for FSS 430 foil with high ridging resistance.Overall,the improvement in the ridging resistance of FSS 430 foil can be attributed to the reduction in the fraction of{001}<110>and{114}<110>components by optimization of the rolling and annealing processes.
文摘Stripping injection overcomes the limitations of Liouville's theorem and is widely used for beam injection and accumulation in high-intensity synchrotrons.The interaction between the stripping foil and beam is crucial in the study of stripping injection,particularly in low-energy stripping injection synchrotrons,such as the XiPAF synchrotron.The foil thickness is the main parameter that affects the properties of the beam after injection.The thin stripping foil is reinforced with collodion during its installation.However,the collodion on the foil surface makes it difficult to determine its equivalent thickness,because the mechanical measurements are not sufficiently reliable or convenient for continuously determining foil thickness.We propose an online stripping foil thickness measurement method based on the ionization energy loss effect,which is suitable for any foil thickness and does not require additional equipment.Experimental studies were conducted using the XiPAF synchrotron.The limitation of this method was examined,and the results were verified by comparing the experimentally obtained beam current accumulation curves with the simulation results.This confirms the accuracy and reliability of the proposed method for measuring the stripping foil thickness.
基金funded by the Youth Fund Project of GRINM(No.66922309)the National Natural Science Foundation of China(No.52301220)。
文摘The equimolar NbZrTi medium-entropy alloy(MEA)has attracted attention due to its excellent comprehensive mechanical properties.In this study,the designed body-centered cubic NbZrTiAl_(4)(atomic percent,at%)MEA by Al addition,having a superplastic extensibility of~5000%under cold rolling,enables directly fabricated ultrathin foils with a thickness down to~0.2 mm without any treatments.Particularly,the annealed NbZrTiAl_(4) MEA foils,containing a coherent nanoscale B2,exhibit an ultrahigh yield strength of up to~1130 MPa,which even surpasses the bulk counterpart,while maintaining a good fracture elongation of up to~14%.The Al addition induced a stronger solid solution strengthening and fine-grain strengthening in the foils.Complex dislocation interactions and dislocation–B2 interactions promoted a dynamical formation of dislocation bands,which yielded work-hardening ability and tensile ductility.These findings provide a novel strategy for the design of ultrathin refractory medium-entropy foils to break through their performance limits at ultrahigh temperatures and guide the design of high-performance lightweight foils for structural applications.
基金supported by the National Natural Science Foundation of China(Nos.52204401,52005432)Hebei Natural Science Foundation of China(No.E2021203179),Excellent Young Talents Program of University of Anhui Province,China(No.gxyq2022093)Excellent Youth Research Projects in Universities of Anhui Province,China(No.2022AH030153).
文摘The edge crack behavior of copper foil in asymmetrical micro-rolling was studied.The effects of the speed ratio between rolls,grain size and stress state in the deformation zone on edge cracks of the rolled piece in asymmetrical rolling were analyzed.Low plasticity,uneven deformation and longitudinal secondary tensile stress generated in the edge area of the rolled piece during the rolling process are the main causes of edge cracks.The larger the grain size of the rolled piece,the smaller the number of edge cracks and the deeper the expansion depth,and the larger the spacing between cracks under the same rolling reduction.Asymmetrical rolling can effectively increase the rolling reduction at when the copper foil fist shows edge cracks compared to symmetrical rolling.This enhancement is attributed to the shearing stress induced by asymmetrical rolling,which reduces the rolling force and longitudinal secondary tensile stress,and increases the residual compressive stress on the surface of the rolled piece.The edge crack defects of copper foil can be effectively reduced by increasing the speed ratio between the rolls in asymmetrical rolling.
基金Project(51975167)supported by the National Natural Science Foundation of China。
文摘In order to gain a deeper understanding of the effect of pulsed current on the mechanical properties and size effect of nanocrystalline Ni foils,nanocrystalline Ni foils with different grain thickness-to-grain size ratios(λ)were prepared using pulsed electrodeposition in this paper and unidirectional tensile experiments were carried out at room temperature with different currents and their applied directions.The experimental results show that the nanocrystalline Ni foil produces an obvious electroplasticity effect after applying the current field,and when 300<λ<1100,the current weakens the size effect of nanocrystalline Ni foils to a certain extent,and the angle between the current direction and the deformation direction also affects the mechanical response of nanocrystalline Ni foils,and when the angle between the current direction and the deformation direction is 0°,electroplasticity effect is the best,and the current has the most significant effect of abating the size effect of the material.The mechanism of unidirectional tensile deformation of nanocrystalline Ni foils under the effect of pulsed current was analyzed using TEM and TKD.It was found that the applied pulse current increased the activity of the nanocrystalline boundaries,promoted the movement of dislocations,and reduced the tendency of dislocation entanglement.The higher the peak current density and the smaller the angle between the direction of the current and the direction of deformation,the smaller the grain boundary orientation difference,the more dispersed the grain orientation,and the lower the density of geometrically necessary dislocations(GND)in the deformed nanocrystalline foil,the more significant the effect on material plasticity improvement.
基金supported by the National Key Research and Development Program of China(2022YFB3708400)the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)+4 种基金the Youth Talent Support Programme of Guangdong Provincial Association for Science and Technology(SKXRC202301)the Guangdong Academy of Science Fund(2020GDASYL-20200101001,2023GDASQNRC-0210,2023GDASQNRC-0321)the Guangdong Science and Technology plan project(2023A0505030002)the GINM’Special Project of Science and Technology Development(2023GINMZX-202301020108)Evaluation Project of Guangdong Provincial Key Laboratory(2023B1212060043).
文摘In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The results show that compared to 100μm thick Ti foil,10μm thick Ti foil is more prone to fracture and is evenly distributed in fragments at the interface.The introduction of Ti foil can effectively refine the grain size of Mg layers of as-rolled Mg/Al composite plates,10μm thick Ti foil has a better refining effect than 100μm thick Ti foil.Ti foil can effectively increase the yield strength(YS)and ultimate strength(UTS)of as-rolled Mg/Al composite plates,10μm thick Ti foil significantly improves the elongation(El)of Mg/Al composite plate,while 100μm thick Ti foil slightly weakens the El.After annealing at 420℃ for 0.5 h and 4 h,Ti foil can inhibit the formation of intermetallic compounds(IMCs)at the interface of Mg/Al composite plates,which effectively improves the YS,UTS and El of Mg/Al composite plates.In addition,Ti foil can also significantly enhance the interfacial shear strength(SS)of Mg/Al composite plates before and after annealing.
基金supported by the Quzhou Science and Technology Bureau Project(2023D023,2023D030,2023D002,and2024D028)the Joint Funds of the Zhejiang Provincial Natural Science Foundation of China(LZY23B030002)+3 种基金the Shijiazhuang Shangtai Technology Co.,Ltd.Hebei Provincial Department of Science and Technology(24291101Z)the International Cooperation Projects of Sichuan Provincial Department of Science and Technology(2021YFH0126)the Sichuan Provincial Science and Technology Department's key research project(2023YFG0203)。
文摘Metal foils have emerged as one of the promising materials for anode-free batteries due to their high energy density and scalability in production.The unclear lithium plating/stripping kinetics of metal foil current collectors in anode-free batteries was addressed by using the non-destructive distribution of relaxation times(DRT)analysis to systematically investigate the lithium transport behavior of 14 metal foils and its correlation with electrochemical performance.By integrating energy-dispersive spectro scopy(EDS),cyclic voltammetry(CV),and galvanostatic testing,the exceptional properties of indium(In),tin(Sn),and silver(Ag)were revealed:the Li-In alloying reaction exhibits high reversibility,Li-Sn alloys demonstrate outstanding cycling stability,and the Li-Ag solid-solution mechanism provides an ideal lithium deposition interface on the silver substrate.The DRT separates the polarization internal resistance of lithium ions passing through the SEI layer(R_(sei),τ2)and the polarization internal resistance of lithium ions undergoing charge transfer reaction at the electrolyte/electrode interface(R_(ct),τ3)by decoupling the electrochemical impedance spectroscopy(EIS).For the first time,the correlation betweenτ2,τ3,and the cycle life/Coulombic efficiency of alloy/solid-solution metals was established,while non-alloy metals are not suitable for this method due to differences in lithium deposition mechanisms.This study not only illuminates the structure-property relationship governing the lithium kinetics of metal foil electrodes but also provides a novel non-destructive analytical strategy and theoretical guidance for the rational design of stable anodes in high-energy-density batteries,facilitating the efficient screening and optimization of anode-free battery.
基金National Natural Science Foundation of China (Grant No.11872013) to provide fund for conducting experiments。
文摘The integration method of exploding foil initiator system(EFIs) used to be researched to broaden its application range in military and aerospace in the last few decades.In order to lower the firing voltage below 1 kV,an integrated EFIs with enhanced energy efficiency was designed.Corresponding exploding foil initiator chips were fabricated in batch via micro electromechanical systems technology by integrating a unified foil,a flyer layer and a barrel on a glass substrate successively,meanwhile its package of the whole system was proposed at a volume of 2.194 cm^(3).The structural parameters were determined by predicted performance including flyer velocity,impact behavior and conduction property via the proposed theoretical models and the static electric field simulation.As expect,this integrated EFIs exhibited excellent functions,which could accelerate the flyer to a terminal velocity over 4 km/s and preeminently initiate HNS-IV pellet at a circuit of 0.24 μF/0.9 kV.Furthermore,the theoretical design,fabrication and performance test have been all included to validate the feasibility of this integrated EFIs that was beneficial for its commercial development in the future.
文摘Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ignition mechanism of EFIs directly igniting pyrotechnics.An oscilloscope,a photon Doppler velocimetry,and a plasma spectrum measurement system were employed to obtain information of electric characteristics,impact pressure,and plasma temperature.The results of the electric characteristics and the impact pressure were inconsistent with ignition results.The only thing that the ignition success tests had in common was that their plasma all had a relatively long period of high-temperature duration(HTD).It eventually concludes that the ignition mechanism in this research is the microconvection heat transfer rather than the shock initiation,which differs from that of exploding foil initiators detonating explosives.Furthermore,the methods for evaluating the ignition success of semiconductor bridge initiators are not entirely applicable to the tests mentioned in this paper.The HTD is the critical parameter for judging the ignition success,and it is influenced by two factors:the late time discharge and the energy of the electric explosion.The longer time of the late time discharge and the more energy of the electric explosion,the easier it is to expand the HTD,which improves the probability of the ignition success.
基金financially supported by the National Key Research and Development Program of China(Nos.2022 YFB3709300 and 2021YFB3701000)the National Natural Science Foundation of China(Nos.52271090 and 52071036)+1 种基金the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030006)the Independent Research Project of State Key Laboratory of Mechanical Transmissions(Nos.SKLMT-ZZKT-2022Z01 and S KLMT-ZZKT-2022M12)。
文摘Magnesium and magnesium alloy foils have great potential for application in battery anodes,electromagnetic shielding,optics and acoustics,and biology because of their excellent specific damping,internal dissipation coefficients,magnetic and electrical conductivities,as well as high theoretical specific capacity.However,magnesium alloys exhibit poor deformation ability due to their hexagonal close-packed crystal structure.Preparing magnesium and magnesium alloy foils with thicknesses of less than 0.1 mm is difficult because of surface oxidation and grain growth at high temperatures or severe anisotropy after cold rolling that leads to cracks.Numerous methods have been applied to prepare magnesium alloy foils.They include warm rolling,cold rolling,accumulative roll bonding,electric plastic rolling,and on-line heating rolling.Defects of magnesium and magnesium alloy foils during preparation,such as edge cracks and breakage,are important factors for consideration.Herein,the current status of the research on magnesium and magnesium alloy foils is summarized from the aspects of foil preparation,defect control,performance characterization,and application prospects.The advantages and disadvantages of different preparation methods and defect(edge cracks and breakage)mechanisms in the preparation of foils are identified.
基金financially supported by Guangdong Major Project of Basic and Applied Basic Research(No.2021B0301030002)the National Natural Science Foundation of China(No.52025023)the Key R&D Program of Guangdong Province(No.2020B010189001).
文摘Depending on the production process,copper(Cu)foils can be classified into two types,i.e.,rolled copper(r-Cu)foils and electrolytic copper(e-Cu)foils.Owing to their high electrical conductivity and ductility at low cost,e-Cu foils are employed extensively in modern industries and account for more than 98%of the Cu foil market share.However,industrial e-Cu foils have never been single-crystallized due to their high density of grain boundaries,various grain orientations and vast impurities originating from the electrochemical deposition process.Here,we report a methodology of transforming industrial e-Cu foils into single crystals by facet copy from a single-crystal template.Different facets of both low and high indices are successfully produced,and the thickness of the single crystal can reach 500μm.Crystallographic characterizations directly recognized the single-crystal copy process,confirming the complete assimilation impact from the template.The obtained single-crystal e-Cu foils exhibit remarkably improved ductility(elongation-to-fracture of 105%vs.25%),fatigue performance(the average numbers of cycles to failure of 1600 vs.200)and electrical property(electrical conductivity of 102.6%of the international annealed copper standard(IACS)vs.98.5%)than original ones.This work opens up a new avenue for the preparation of single-crystal e-Cu foils and may expand their applications in high-speed,flexible,and wearable devices.
基金the Science and Technology on Applied Physical Chemistry Laboratory, China (Grant No.6142602220101) to provide fund for conducting experiments。
文摘Explosion-electricity coupling(EEC) is a technical method to induce electric energy into the plasma material produced by explosion to improve the output of explosion.Exploding foil initiator(EFI) which could produce plasma during electric explosion can serve as a good carrier for studying the EEC.To investigate the enhancement ability and mechanism of EEC in EFI ignition performance,a kind of EFI chips which could realize the EEC effect was designed and fabricated to observe the characteristics of current and voltage,flyer and plasma temperature during Boron Potassium Nitrate(BPN) ignition of the EFI.It was found that the EEC could enhance EFI ignition in terms of energy utilization,ignition contact surface,and high-temperature sustainability of plasma:firstly,the EEC prolonged the late time discharge(LTD) phase of the electric explosion,making the energy of capacitor effectively utilized;secondly,the EEC could create a larger area of ignition contact surface;last of all,the EEC effect enhanced its hightemperature sustainability by sustaining continuous energy input to plasma.It also was found that the ignition voltage of BPN could be reduced by nearly 600 V under the condition of 0.4 μF capacitance.The research has successfully combined EEC with EFI,revealing the behavioral characteristics of EEC and demonstrating its effective enhancement of EFI ignition.It introduces a new approach to improving EFI output,which is conducive to low-energy ignition of EFI,and expected to take the ignition technology of EFI to a new level.
基金Project supported by the Basic and Applied Basic Research Foundation of Guangdong Province,China(Grant Nos.2019A1515110302 and 2022A1515140003)the Key Research and Development Program of Guangdong Province,China(Grant Nos.2020B010189001,2021B0301030002,2019B010931001,and 2018B030327001)+5 种基金the National Natural Science Foundation of China(Grant Nos.52172035,52025023,52322205,51991342,52021006,51991344,52100115,11888101,92163206,12104018,and 12274456)the National Key Research and Development Program of China(Grant Nos.2021YFB3200303,2022YFA1405600,2018YFA0703700,2021YFA1400201,and 2021YFA1400502)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB33000000)the Pearl River Talent Recruitment Program of Guangdong Province,China(Grant No.2019ZT08C321)China Postdoctoral Science Foundation(Grant Nos.2020T130022 and 2020M680178)the Science and Technology Plan Project of Liaoning Province,China(Grant No.2021JH2/10100012).
文摘High-purity copper(Cu) with excellent thermal and electrical conductivity, is crucial in modern technological applications, including heat exchangers, integrated circuits, and superconducting magnets. The current purification process is mainly based on the zone/electrolytic refining or anion exchange, however, which excessively relies on specific integrated equipment with ultra-high vacuum or chemical solution environment, and is also bothered by external contaminants and energy consumption. Here we report a simple approach to purify the Cu foils from 99.9%(3N) to 99.99%(4N) by a temperature-gradient thermal annealing technique, accompanied by the kinetic evolution of single crystallization of Cu.The success of purification mainly relies on(i) the segregation of elements with low effective distribution coefficient driven by grain-boundary movements and(ii) the high-temperature evaporation of elements with high saturated vapor pressure.The purified Cu foils display higher flexibility(elongation of 70%) and electrical conductivity(104% IACS) than that of the original commercial rolled Cu foils(elongation of 10%, electrical conductivity of ~ 100% IACS). Our results provide an effective strategy to optimize the as-produced metal medium, and therefore will facilitate the potential applications of Cu foils in precision electronic products and high-frequency printed circuit boards.
基金National Natural Science Foundation of China(Grant No.11872013)for supporting this project.
文摘Al/Ni reactive multilayer foil(RMF)possesses excellent comprehensive properties as a promising substitute for traditional Cu bridge.A theoretical resistivity model of Al/Ni RMF was developed to guide the optimization of EFIs.Al/Ni RMF with different bilayer thicknesses and bridge dimensions were prepared by MEMS technology and electrical explosion tests were carried out.According to physical and chemical reactions in bridge,the electrical explosion process was divided into 5 stages:heating of condensed bridge,vaporization and diffusion of Al layers,intermetallic combination reaction,intrinsic explosion,ionization of metal gases,which are obviously shown in measured voltage curve.Effects of interface and grain boundary scattering on the resistivity of film metal were considered.Focusing on variations of substance and state,the resistivity was developed as a function of temperature at each stage.Electrical explosion curves were calculated by this model at different bilayer thicknesses,bridge dimensions and capacitor voltages,which showed an excellent agreement with experimental ones.
文摘Ultrasonic baths and sonochemical reactors are widely used in industrial applications dealing with surface cleaningand chemical synthesis. The processes of erosion, cleaning and structuring of the surface can be typically controlledby changing relevant influential parameters. In particular, in this work, we experimentally investigate theeffect of NaCl concentration (0–5.5 mol/L) on the erosion of an aluminum foil under ultrasonic exposure at afrequency of 28 kHz. Special attention is paid to the determination of cavitation zones and their visualizationusing heat maps. It is found that at low NaCl concentration (0.3 mol/L), the foil destruction rate is higher thanin distilled water. At higher concentrations of salt, cavitation takes place mainly in the upper part of the container.
基金Project supported by University New Materials Disciplines Constructions Program of Beijing Region,ChinaProject(51172102/E020801) supported by the National Natural Science Foundation of China
文摘The aluminum foil for high voltage aluminum electrolytic capacitor was immersed in 0.5 mol/L H3PO4 or 0.125 mol/L NaOH solution at 40 ℃ for different time and then DC electro-etched in 1 mol/L HC1＋2.5 mol/L H2SO4 electrolyte at 80 ℃. The pitting potential and self corrosion potential of A1 foil were measured with polarization curves （PC）. The potentiostatic current--time curve was recorded and the surface and cross section images of etched A1 foil were observed with SEM. The electrochemical impedance spectroscopy （EIS） of etched A1 foil and potential transient curves （PTC） during initial etching stage were measured. The results show the chemical pretreatments can activate A1 foil surface, facilitate the absorption, diffusion and migration of C1- onto the A1 foil during etching, and improve the initiation rate of meta-stable pits and density of stable pits and tunnels, leading to much increase in the real surface area and special capacitance of etched A1 foil.
基金Project (51172102) supported by the National Natural Science Foundation of ChinaProject (BS2011CL011) supported by Promotive Research Fund for Young and Middle-aged Scientists of Shandong Province(doctor fund),China
文摘The Al foil for high voltage Al electrolytic capacitor usage was immersed in 5.0%NaOH solution containing trace amount of Zn2＋and Zn was chemically plated on its surface through an immersion-reduction reaction. Such Zn-deposited Al foil was quickly transferred into HCl-H 2 SO 4 solution for DC-etching. The effects of Zn impurity on the surface and cross-section etching morphologies and electrochemical behavior of Al foil were investigated by SEM, polarization curve （PC） and electrochemical impedance spectroscopy （EIS）. The special capacitance of 100 V formation voltage of etched foil was measured. The results show that the chemical plating Zn on Al substrate in alkali solution can reduce the pitting corrosion resistance, enhance the pitting current density and improve the density and uniform distribution of pits and tunnels due to formation of the micro Zn-Al galvanic local cells. The special capacitance of etched foil grows with the increase of Zn2＋concentration.
