We present the first systematic experimental validation of return-current-driven cylindrical implosion scaling in micrometer-sized Cu and Al wires irradiated by J-class femtosecond laser pulses.Employing XFEL-based im...We present the first systematic experimental validation of return-current-driven cylindrical implosion scaling in micrometer-sized Cu and Al wires irradiated by J-class femtosecond laser pulses.Employing XFEL-based imaging with sub-micrometer spatial and femtosecond temporal resolution,supported by hydrodynamic and particle-in-cell simulations,we reveal how return current density depends precisely on wire diameter,material properties,and incident laser energy.We identify deviations from simple theoretical predictions due to geometrically influenced electron escape dynamics.These results refine and confirm the scaling laws essential for predictive modeling in high-energy-density physics and inertial fusion research.展开更多
1.Introduction.The Ti6Al4V alloy is extensively utilized across various indus-trial sectors due to its favorable characteristics,such as lightweight design,high strength,and resistance to corrosion[1].In effort s to f...1.Introduction.The Ti6Al4V alloy is extensively utilized across various indus-trial sectors due to its favorable characteristics,such as lightweight design,high strength,and resistance to corrosion[1].In effort s to further reduce weight,functional elements like electric actuators can be substituted with intelligent materials like shape memory alloys(SMAs)[2,3].Among SMAs,NiTi alloy stands out for its sens-ing and actuation capabilities,significantly enhancing the safety and reliability of engineering structures[4,5].Integrating Ti6Al4V and NiTi alloys within a single component holds the potential to provide precise feedback on mechanical,thermal,or environmen-tal conditions[6,7].展开更多
Microstructure uniformity of the Al-Nd target materials with Al11 Nd_(3) significantly affects the performance of the fabricated Al-Nd film,which is widely used as wiring material in large-size thin-film transistor li...Microstructure uniformity of the Al-Nd target materials with Al11 Nd_(3) significantly affects the performance of the fabricated Al-Nd film,which is widely used as wiring material in large-size thin-film transistor liquid crystal display(TFT-LCD)panels.Understanding the inherent mechanical properties and chemical bonds of Al11 Nd_(3) is crucial for homogenizing the Al-Nd target.Here,by a combined experimental and ab-initio theoretical study,the microstructure and deformability of the Al-3wt%Nd alloy and the inherent mechanical properties and chemical bonds of Al11 Nd_(3) were investigated comprehensively.The Al-3wt%Nd alloy is composed of the pre-eutecticα-Al matrix and the eutecticα-Al and a high stableα-Al11 Nd_(3) phase.During the plastic deformation,the eutectic microstructure transforms from a cellular to a lamel-lar shape,while the morphology and dimension ofα-Al11 Nd_(3) are not changed significantly.By examin-ing ideal tensile strength,elastic moduli,hardness and brittleness-ductility,the hardness-brittleness ofα-Al11 Nd_(3) is quantitatively evaluated,accounting for its difficulties of plastic deformation and fragmen-tation.Combining band structure,population analysis,topological analysis and crystal orbital Hamilton population,we found thatα-Al11 Nd_(3) possesses two types of chemical bonds:the Nd-Al and Al-Al bonds.The former is a typical ionic bond with electron transfer from Nd to Al,while the latter,dominated by both 3 s-3 p and 3 p-3 p interactions,is a weak covalent bond.The mixed chemical bond is responsible for the high hardness-brittleness ofα-Al11 Nd_(3).This work is expected to lay a foundation for Al-Nd alloy and catalyze the fabrication of high-quality Al-Nd target materials.展开更多
To improve the slow kinetics and poor mechanical strength of aqueous silver peroxide−aluminum(AgO−Al)battery cathode materials,the effects of different binders including polytetrafluoroethylene(PTFE)and polyvinylpyrro...To improve the slow kinetics and poor mechanical strength of aqueous silver peroxide−aluminum(AgO−Al)battery cathode materials,the effects of different binders including polytetrafluoroethylene(PTFE)and polyvinylpyrrolidone(PVP)on the AgO cathode material were investigated.The samples were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),cyclic voltammetry(CV),electrochemical impedance spectrum(EIS),and galvanostatic discharge.In contrast to the pure AgO and AgO−PTFE electrodes,the results demonstrated that the PVP effectively bound the electrode materials together.The prepared AgO−PVP as the cathode material of AgO−Al batteries could improve the battery capacity,exhibiting a high specific capacity(389.95 mA·h/g at 500 mA/cm^(2)),a high operating voltage(1.75 V at 500 mA/cm^(2)),a maximum energy density(665.65 W·h/kg),and a maximum power density(5236 W/kg).Furthermore,the electrochemical mechanism of the AgO−PVP cathode material was examined,revealing that the electrode exhibited rapid ion diffusion and effective interfacial ion/electron transport.展开更多
Cu/Al bar clad material was fabricated by a drawing process and a subsequent heat treatment.During these processes,intermetallic compounds have been formed at the interface of Cu/Al and have affected its bonding prope...Cu/Al bar clad material was fabricated by a drawing process and a subsequent heat treatment.During these processes,intermetallic compounds have been formed at the interface of Cu/Al and have affected its bonding property.Microstructures of Cu/Al interfaces were observed by OM,SEM and EDX Analyser in order to investigate the bonding properties of the material.According to the microstructure a series of diffusion layers were observed at the interface and the thicknesses of diffusion layers have increased with aging time as a result of the diffusion bonding.The interfaces were composed of 3-ply diffusion layers and their compositions were changed with aging time at 400 °C.These compositional compounds were revealed to be η2,(θ+η2),(α+θ) intermetallic phases.It is evident from V-notch impact tests that the growth of the brittle diffusion layers with the increasing aging time directly influenced delamination distance between the Cu sleeve and the Al core.It is suggested that the proper holding time at 400 °C for aging as post heat treatment of a drawn Cu/Al bar clad material would be within 1 h.展开更多
The 2024/3003 aluminum gradient alloys are prepared by semi continuous casting. The influences of throttle bore diameter of embedded nozzle and temperature of internal melt on composition distribution, macrostructure,...The 2024/3003 aluminum gradient alloys are prepared by semi continuous casting. The influences of throttle bore diameter of embedded nozzle and temperature of internal melt on composition distribution, macrostructure, hardness are analyzed, and the stability of gradient distribution of composition, macrostructure and hardness along the axial direction of the ingot is also studied. The results show that diffe rent composition profiles can be achieved by adjusting the processing parameters; the volume fraction of inner alloy in the ingot can be increased by enlarging the throttle bore diameter and elevating the temperature of inner melt; quasi steady solidification can be realized within 20 s during cast processing, and consistent quality ingot is obtained by controlling the casting speed and liquid height of inner melt.展开更多
A uniform Al-doped LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) cathode material was prepared using a coprecipitation method to take advantage of the positive effect of Al on regenerated NCM(Ni,Co,Mn)cathode materials and ameliora...A uniform Al-doped LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) cathode material was prepared using a coprecipitation method to take advantage of the positive effect of Al on regenerated NCM(Ni,Co,Mn)cathode materials and ameliorate cumbersome and high-cost impurity removal processes during lithium-ion battery recycling.When the Al^(3+) content in the leachate was 1 at.%with respect to the total amount of transition metals(Ni,Co,and Mn),the produced Al-doped NCM cathode material increased concentrations of lattice oxygen and Ni^(2+).The initial specific capacity at 0.1C was 167.4 mA·h/g,with a capacity retention of 79.1%after 400 cycles at 1C.Further,this Al-doped sample showed improved rate performance and a smaller electrochemical impedance.These findings provide a reference for developing industrial processes to resynthesize cathode materials with improved electrochemical performance by incorporating Al^(3+) impurities produced during lithium-ion battery recycling.展开更多
Spherical LiNi0.8Co0.15Al0.05O2 OOH precursor prepared by a co-oxidation-controlled crystallization method, was used to synthesize LiNi0.5Co0.15Al0.05O2. The obtained LiNi0.8Co0.15Al0.05O2 materials showed excellent e...Spherical LiNi0.8Co0.15Al0.05O2 OOH precursor prepared by a co-oxidation-controlled crystallization method, was used to synthesize LiNi0.5Co0.15Al0.05O2. The obtained LiNi0.8Co0.15Al0.05O2 materials showed excellent electrochemical performance, with an initial discharge capacity of 193.5 mAh/g and capacity retention of 95.1% after 50 cycles when cycled at 0.2 C rate between 2.8 and 4.3 V.展开更多
Al 1060/pure iron clad materials were produced by vacuum roll bonding. The effects of preheating temperature, vacuum roll reduction and initial thickness of the A11060 sheet on the metal interface and bonding strength...Al 1060/pure iron clad materials were produced by vacuum roll bonding. The effects of preheating temperature, vacuum roll reduction and initial thickness of the A11060 sheet on the metal interface and bonding strength were investigated. The interfacial microstructure was investigated and the mechanical properties of the joint were evaluated by shear testing. The bonding strength of the clad materials was generally enhanced by increasing the total reduction or preheating temperature, which caused the metal interface to flatten. No obvious reaction or diffusion layer was observed at the interface between Al 1060 and pure iron. The bonding strength increased with decreasing the initial thickness of the Al 1060 sheets. The Al 1060/pure iron clad materials were soldered with Zn-Al alloy by using an ultrasonic-assisted method. Strong bonding of the Al 1060 layer and Al 7N01 was realized without obvious Al 1060 dissolution or effect on the initial interface of Al 1060/pure iron clad materials by soldering at relatively low temperature.展开更多
Data-mining techniques using machine learning are powerful and efficient for materials design, possessing great potential for discovering new materials with good characteristics. Here, this technique has been used on ...Data-mining techniques using machine learning are powerful and efficient for materials design, possessing great potential for discovering new materials with good characteristics. Here, this technique has been used on composition design for La（Fe,Si/Al）（13）-based materials, which are regarded as one of the most promising magnetic refrigerants in practice. Three prediction models are built by using a machine learning algorithm called gradient boosting regression tree（GBRT） to essentially find the correlation between the Curie temperature（TC）, maximum value of magnetic entropy change（（？SM）（max））,and chemical composition, all of which yield high accuracy in the prediction of TC and（？SM）（max）. The performance metric coefficient scores of determination（R^2） for the three models are 0.96, 0.87, and 0.91. These results suggest that all of the models are well-developed predictive models on the challenging issue of generalization ability for untrained data, which can not only provide us with suggestions for real experiments but also help us gain physical insights to find proper composition for further magnetic refrigeration applications.展开更多
A facile and economical approach was developed for the large-scale production of powdered core-shell structured PTFE/Al (CS-PA) energetic materials through ultrasonic-assisted mixing. The low-cost micrometer-sized PTF...A facile and economical approach was developed for the large-scale production of powdered core-shell structured PTFE/Al (CS-PA) energetic materials through ultrasonic-assisted mixing. The low-cost micrometer-sized PTFE and Al particles were used as starting materials. Under high-power ultrasonic waves, the PTFE powder was dispersed into nano-to sub-micrometer-sized particles and then encapsulated the Al microparticles to form the core-shell structure. The heat of combustion, burning rate, and pressurization rate of the powdered CS-PA were measured. The thermal-initiated reaction behavior was further evaluated using thermogravimetry-differential scanning calorimetry. Subsequently, the bulk CS-PA with a uniform microstructure was obtained via cold isostatic pressing of the powdered CS-PA followed by vacuum sintering. For the bulk CS-PA, the quasi-static compression behavior was characterized, and the impact-initiated reaction processes were conducted using the Split Hopkinson Pressure Bar (SHPB) and evaluated by a high-speed camera. Compared to physically mixed PTFE/Al materials, the powdered and bulk CS-PA demonstrated enhanced thermal- and impact-initiated reaction characteristics respectively, proving the effectiveness of our approach for constructing core-shell structures.展开更多
In this paper,the ballistic impact experiments,including impact test chamber and impact double-spaced plates,were conducted to study the reaction behaviors of a novel functionally graded reactive material(FGRM),which ...In this paper,the ballistic impact experiments,including impact test chamber and impact double-spaced plates,were conducted to study the reaction behaviors of a novel functionally graded reactive material(FGRM),which was composed of polytetrafluoroethylene/aluminum(PTFE/Al)and PTFE/Al/bismuth trioxide(Bi_(2)O_(3)).The experiments showed that the impact direction of the FGRM had a significant effect on the reaction.With the same impact velocity,when the first impact material was PTFE/Al/Bi_(2)O_(3),compared with first impact material PTFE/Al,the FGRM induced higher overpressure in the test chamber and larger damaged area of double-spaced plates.The theoretical model,which considered the shock wave generation and propagation,the effect of the shock wave on reaction efficiency,and penetration behaviors,was developed to analyze the reaction behaviors of the FGRM.The model predicted first impact material of the FGRM with a higher shock impedance was conducive to the reaction of reactive materials.The conclusion of this study provides significant information about the design and application of reactive materials.展开更多
Five-layered Al/Al-Cu functionally graded material （FGM） was prepared by powder metallurgy technology, and the subsequent heat treatment was carried out for the graded material. The microstructures and distribution ...Five-layered Al/Al-Cu functionally graded material （FGM） was prepared by powder metallurgy technology, and the subsequent heat treatment was carried out for the graded material. The microstructures and distribution of Cu element under pressure sintering （F）, solution treatment （T4） and artificial aging treatment （T6） were investigated, and the Vickers hardness and flexural properties of different states were tested. The results showed that sintered compact with dense structure and compositional continuous change was obtained. The second-phase CuAl 2 was dispersively distributed along grain boundary of Al matrix. After solution treatment at 503 C for 3 h, CuAl 2 phase obviously decreased and dissolved into the Al matrix, and the flexural strength was thereupon enhanced to 228.5 MPa. With the subsequent aging treatment at 150 C for 15 h, the majority of flake shaped precipitates θ phases were uniformly distributed in the matrix. And the distribution of Cu element became gradual continuous compared to sintered compact. Meanwhile, the flexural strength increased further, which accompanied with the decline of plasticity.展开更多
Microstructure and interracial reactions of Al2O3 joints brazed with Al2O3-particulate-contained composite Ag-Cu-Ti filler material were researched by scanning electron microscopy(SEM),electron probe microscopy analys...Microstructure and interracial reactions of Al2O3 joints brazed with Al2O3-particulate-contained composite Ag-Cu-Ti filler material were researched by scanning electron microscopy(SEM),electron probe microscopy analysis(EPMA),energy dispersive spectroscopy(EDS)and X-ray diffraction(XRD).The interracial reaction layer thickness of joints brazed with conventional active filler metal and active composite filler materials with different volume fraction of Al2O3 particulate was also studied.The experimental results indicated although there were Al2O3 particulates added into active filler metals,the time dependence of interracial layer growth of joints brazed with active composite filler material is t^1/2 as described by Fickian law as the joints brazed with conventional active filler metal.展开更多
B4C reinforced Al composites are widely used as neutron absorbing materials(NAMs)due to excellent neutron absorbing efficiency,however,such NAMs exhibit poor high-temperature properties.To meet the requirement for str...B4C reinforced Al composites are widely used as neutron absorbing materials(NAMs)due to excellent neutron absorbing efficiency,however,such NAMs exhibit poor high-temperature properties.To meet the requirement for structure-function integration,NAMs with enhanced high-temperature mechanical properties are desired.In this work,a novel(B4 C+Al_(2)O_(3))/Al NAM with netlike distribution of Al_(2)O_(3)was fabricated by powder metallurgy method and subjected to high-temperature tensile creep test.It was shown that the creep resistance was enhanced by several orders of magnitude via the addition of only2.1 vol.%netlike-distributed Al_(2)O_(3).(B_(4)C+Al_(2)O_(3))/Al exhibited high apparent stress exponents ranging from 16 to 25 and high apparent activation energy of 364 kJ/mol.The creep behaviour could be rationalized using the substructure-invariant model and its rupture behaviour could be described by the Dobes-Milicka equation.展开更多
Ti1Al2O3 Functionally Gradient Material (FGM) was prepared by an explosive compaction/SHS process. Ten sheets of the compounding powder were laminated and pressed to get a green body of FGM. It was then compacted expl...Ti1Al2O3 Functionally Gradient Material (FGM) was prepared by an explosive compaction/SHS process. Ten sheets of the compounding powder were laminated and pressed to get a green body of FGM. It was then compacted explosively By burying the explosive compaction body into a stoichiometric Al/TiO2 mixture and igniting the combustion of the stoichiometric Al/TiO2 mixture, the SHS reaction of the explosive compaction body was initiated by the heat released from the combustion of the stoichiometric Al/TiO2 mixture. In this way, Ti/Al2O3 FGM was synthesized. The adiabatic temperatures of each gradient layer were calculated when the preheating temperatures were 298 K and 1173 K, respectively The microstructure, composition and properties of Ti/Al2O3 FGM and the reaction mechanism of each gradient layer were studied. It was found that Ti/Al2O3 FGM prepared by the explosive compaction/SHS process had a high density and a high microhardness. Its structure, composition and properties showed apparent gradient distribution. The structure of the standard stoichiometric ratio gradient layer of FGM was a network structure. Its reaction mode could be described as follows: Al powder melted first, then the molten Al penetrated into the TiO2 zone and reacted with TiO2, and big pores were left in the original positions of Al powder. The reaction of gradient layers with the addition of Al3O3 as diluents was similar to that of the standard stoichiometric ratio gradient layer, so were their structure and composition. However, the reaction of gradient layers with the addition of Ti as diluents was more complex and the composition deviated slightly from the designed one展开更多
The lanthanum aluminum mesoporous materials were synthesized using sodium dodecyl sulfate as a template agent by ultrasonic hydrothermal method.The resulting samples were characterized by low angle X-ray diffraction（...The lanthanum aluminum mesoporous materials were synthesized using sodium dodecyl sulfate as a template agent by ultrasonic hydrothermal method.The resulting samples were characterized by low angle X-ray diffraction（XRD）,N2 adsorption-desorption studies,transmission electron microscopy（TEM）and surface morphology analysis（SEM）,surface acid（NH3-TPD）,reducibility properties（TPR）,X-ray energy dispersive spectrometer（EDS）and thermogravimetric analysis（TG/DTG）.A l/La composite mesoporous material were synthesized with n（Al）︰n（La）=70︰1.0,80°C of reaction temperature,20 h of reaction time,12 h of crystallization time,650°C of calcination temperature.The specific surface area of the sample is 273.90 m 2 ·g ？1 ,with the average diameter 5.642 nm and pore volume 0.2354 cm 3 ·g ？1 .The samples have mesoporous structure and its particles are similar to a worm-shaped tubular structure.The influence of calcination temperature on the surface physical and chemical properties of Al/La composited mesoporous materials was examined,and the results showed that the acid strength was increased but the amount of acidic sites is decreased as the calcination temperature increased.It was found that the sample calcined at 650°C had appropriate acid content,acid strength and better reducibility.展开更多
Accurate material constitutive model is considered highly necessary to perform finite element simulation and analysis.However,it is difficult to establish the material constitutive model because of uncertainty of math...Accurate material constitutive model is considered highly necessary to perform finite element simulation and analysis.However,it is difficult to establish the material constitutive model because of uncertainty of mathematical relationship and constraint of existing experimental condition.At present,there exists considerable gap between finite element simulation result and actual cutting process.Particular emphases were put on investigating the correlation between ＂single factor＂ material constitutive model parameters and temperature for Ti6Al4V alloy,and also establishment of material constitutive model for this kind of material.Theoretical analyses based on dislocation theory and material functional relations showed that material model was deeply affected by variation temperature.By the least squares best fit to the available quasi-static and high-speed impact compression experiment data,material parameters at various temperatures were found.Experimental curves analyses and material parameters comparison showed that the ＂single factor＂ material constitutive model parameters were temperature dependent.Using the mathematical mapping between material parameters and temperature,＂single factor＂ material constitutive model of Ti6Al4V alloy was established,which was proven to be right by comparing with experimental measurements.This work makes clear that the ＂single factor＂ material constitutive model parameters of Ti6Al4V alloy are temperature dependent.At the same time,an accurate material constitutive model is established,which helps to optimize cutting process and control machining distortion for Ti6Al4V alloy aerospace parts.展开更多
The microstructure and mechanical properties of steel/Al structure material produced by additive manufacturing （AM） was investigated in this work based on the cold metal transfer welding. The results show that the m...The microstructure and mechanical properties of steel/Al structure material produced by additive manufacturing （AM） was investigated in this work based on the cold metal transfer welding. The results show that the microstructure gradually changed from the steel side to the aluminum side. The microstructure in the steel layer consisted of vermiform like ferrite and anstenite structure, while in the aluminum layer the microstructure was constituted by c^-A1 grains and typical reticulate distributive Al-Si eutectic structure. Besides, a 7 y.m thickness Ni-Al intermetallic compound layer was emerged at the interface of nickel and aluminum layer. The maximum room-temperature tensile strength of the Steel-Al structure materials was found to be 54 MPa, the rupture morphology showed a brittle fracture characteristic.展开更多
基金partially supported by the Center for Advanced Systems Understanding(CASUS)financed by Germany’s Federal Ministry of Education and Research(BMBF)+2 种基金the Saxon State Government out of the State Budget approved by the Saxon State Parliamentfunding from the European Union’s Just Transition Fund(JTF)within the project Röntgenlaser-Optimierung der Laserfusion(ROLF),Contract No.5086999001co-financed by the Saxon State Government out of the State Budget approved by the Saxon State Parliament.
文摘We present the first systematic experimental validation of return-current-driven cylindrical implosion scaling in micrometer-sized Cu and Al wires irradiated by J-class femtosecond laser pulses.Employing XFEL-based imaging with sub-micrometer spatial and femtosecond temporal resolution,supported by hydrodynamic and particle-in-cell simulations,we reveal how return current density depends precisely on wire diameter,material properties,and incident laser energy.We identify deviations from simple theoretical predictions due to geometrically influenced electron escape dynamics.These results refine and confirm the scaling laws essential for predictive modeling in high-energy-density physics and inertial fusion research.
基金supported by the National Natural Science Foundation of China(Grant No.52235006)the National Key Research and Development Program of China(Grant No.2022YFB4600500)+3 种基金the National Natural Science Foundation of China(Grant Nos.52025053 and 52105303)the Natural Science Foundation of Jilin Province(Grant No.20220101209JC)the Postdoctoral Fellow-ship Program of CPSF(Grant GZC20240587 and GZC20230944)the Graduate Innovation Fund of Jilin University(2024CX063).
文摘1.Introduction.The Ti6Al4V alloy is extensively utilized across various indus-trial sectors due to its favorable characteristics,such as lightweight design,high strength,and resistance to corrosion[1].In effort s to further reduce weight,functional elements like electric actuators can be substituted with intelligent materials like shape memory alloys(SMAs)[2,3].Among SMAs,NiTi alloy stands out for its sens-ing and actuation capabilities,significantly enhancing the safety and reliability of engineering structures[4,5].Integrating Ti6Al4V and NiTi alloys within a single component holds the potential to provide precise feedback on mechanical,thermal,or environmen-tal conditions[6,7].
基金supported by the National Key R&D Program of China(No.2022YFB3504401).
文摘Microstructure uniformity of the Al-Nd target materials with Al11 Nd_(3) significantly affects the performance of the fabricated Al-Nd film,which is widely used as wiring material in large-size thin-film transistor liquid crystal display(TFT-LCD)panels.Understanding the inherent mechanical properties and chemical bonds of Al11 Nd_(3) is crucial for homogenizing the Al-Nd target.Here,by a combined experimental and ab-initio theoretical study,the microstructure and deformability of the Al-3wt%Nd alloy and the inherent mechanical properties and chemical bonds of Al11 Nd_(3) were investigated comprehensively.The Al-3wt%Nd alloy is composed of the pre-eutecticα-Al matrix and the eutecticα-Al and a high stableα-Al11 Nd_(3) phase.During the plastic deformation,the eutectic microstructure transforms from a cellular to a lamel-lar shape,while the morphology and dimension ofα-Al11 Nd_(3) are not changed significantly.By examin-ing ideal tensile strength,elastic moduli,hardness and brittleness-ductility,the hardness-brittleness ofα-Al11 Nd_(3) is quantitatively evaluated,accounting for its difficulties of plastic deformation and fragmen-tation.Combining band structure,population analysis,topological analysis and crystal orbital Hamilton population,we found thatα-Al11 Nd_(3) possesses two types of chemical bonds:the Nd-Al and Al-Al bonds.The former is a typical ionic bond with electron transfer from Nd to Al,while the latter,dominated by both 3 s-3 p and 3 p-3 p interactions,is a weak covalent bond.The mixed chemical bond is responsible for the high hardness-brittleness ofα-Al11 Nd_(3).This work is expected to lay a foundation for Al-Nd alloy and catalyze the fabrication of high-quality Al-Nd target materials.
基金supported by the Fundamental Research Funds for the Central Universities of Central South University,China(No.2022XQLH046)the Technical Area Fund of Foundation Strengthening,China(No.2022-JCJQ-ZD-174-00-20)National Defense Basic Scientific Research Projects,China,and Central South University−Zijin Mining Technical Cooperation Development Project,China.
文摘To improve the slow kinetics and poor mechanical strength of aqueous silver peroxide−aluminum(AgO−Al)battery cathode materials,the effects of different binders including polytetrafluoroethylene(PTFE)and polyvinylpyrrolidone(PVP)on the AgO cathode material were investigated.The samples were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),cyclic voltammetry(CV),electrochemical impedance spectrum(EIS),and galvanostatic discharge.In contrast to the pure AgO and AgO−PTFE electrodes,the results demonstrated that the PVP effectively bound the electrode materials together.The prepared AgO−PVP as the cathode material of AgO−Al batteries could improve the battery capacity,exhibiting a high specific capacity(389.95 mA·h/g at 500 mA/cm^(2)),a high operating voltage(1.75 V at 500 mA/cm^(2)),a maximum energy density(665.65 W·h/kg),and a maximum power density(5236 W/kg).Furthermore,the electrochemical mechanism of the AgO−PVP cathode material was examined,revealing that the electrode exhibited rapid ion diffusion and effective interfacial ion/electron transport.
基金Project supported by the Fundamental Materials Development funded by the Korean Ministry of Knowledge Economy
文摘Cu/Al bar clad material was fabricated by a drawing process and a subsequent heat treatment.During these processes,intermetallic compounds have been formed at the interface of Cu/Al and have affected its bonding property.Microstructures of Cu/Al interfaces were observed by OM,SEM and EDX Analyser in order to investigate the bonding properties of the material.According to the microstructure a series of diffusion layers were observed at the interface and the thicknesses of diffusion layers have increased with aging time as a result of the diffusion bonding.The interfaces were composed of 3-ply diffusion layers and their compositions were changed with aging time at 400 °C.These compositional compounds were revealed to be η2,(θ+η2),(α+θ) intermetallic phases.It is evident from V-notch impact tests that the growth of the brittle diffusion layers with the increasing aging time directly influenced delamination distance between the Cu sleeve and the Al core.It is suggested that the proper holding time at 400 °C for aging as post heat treatment of a drawn Cu/Al bar clad material would be within 1 h.
文摘The 2024/3003 aluminum gradient alloys are prepared by semi continuous casting. The influences of throttle bore diameter of embedded nozzle and temperature of internal melt on composition distribution, macrostructure, hardness are analyzed, and the stability of gradient distribution of composition, macrostructure and hardness along the axial direction of the ingot is also studied. The results show that diffe rent composition profiles can be achieved by adjusting the processing parameters; the volume fraction of inner alloy in the ingot can be increased by enlarging the throttle bore diameter and elevating the temperature of inner melt; quasi steady solidification can be realized within 20 s during cast processing, and consistent quality ingot is obtained by controlling the casting speed and liquid height of inner melt.
基金supported by Anhui Province Research and Development Innovation Project for Automotive Power Battery Efficient Recycling System, China
文摘A uniform Al-doped LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) cathode material was prepared using a coprecipitation method to take advantage of the positive effect of Al on regenerated NCM(Ni,Co,Mn)cathode materials and ameliorate cumbersome and high-cost impurity removal processes during lithium-ion battery recycling.When the Al^(3+) content in the leachate was 1 at.%with respect to the total amount of transition metals(Ni,Co,and Mn),the produced Al-doped NCM cathode material increased concentrations of lattice oxygen and Ni^(2+).The initial specific capacity at 0.1C was 167.4 mA·h/g,with a capacity retention of 79.1%after 400 cycles at 1C.Further,this Al-doped sample showed improved rate performance and a smaller electrochemical impedance.These findings provide a reference for developing industrial processes to resynthesize cathode materials with improved electrochemical performance by incorporating Al^(3+) impurities produced during lithium-ion battery recycling.
基金supported by National Natural Science Foundation of China(No.50604018)National Key Technology R&D Program of China(No.2007BAE12B01)
文摘Spherical LiNi0.8Co0.15Al0.05O2 OOH precursor prepared by a co-oxidation-controlled crystallization method, was used to synthesize LiNi0.5Co0.15Al0.05O2. The obtained LiNi0.8Co0.15Al0.05O2 materials showed excellent electrochemical performance, with an initial discharge capacity of 193.5 mAh/g and capacity retention of 95.1% after 50 cycles when cycled at 0.2 C rate between 2.8 and 4.3 V.
基金the project from the International S&T Cooperation (No.2011DFR 50630)Special Research Program for Innovation Talents from Harbin Municipality of Science and Technology (2012RFXXG071,2010RFQXG020)Harbin Science and Technology Innovation Youth Talents Fund (No.2010RFQXG003)
文摘Al 1060/pure iron clad materials were produced by vacuum roll bonding. The effects of preheating temperature, vacuum roll reduction and initial thickness of the A11060 sheet on the metal interface and bonding strength were investigated. The interfacial microstructure was investigated and the mechanical properties of the joint were evaluated by shear testing. The bonding strength of the clad materials was generally enhanced by increasing the total reduction or preheating temperature, which caused the metal interface to flatten. No obvious reaction or diffusion layer was observed at the interface between Al 1060 and pure iron. The bonding strength increased with decreasing the initial thickness of the Al 1060 sheets. The Al 1060/pure iron clad materials were soldered with Zn-Al alloy by using an ultrasonic-assisted method. Strong bonding of the Al 1060 layer and Al 7N01 was realized without obvious Al 1060 dissolution or effect on the initial interface of Al 1060/pure iron clad materials by soldering at relatively low temperature.
基金supported by the National Basic Research Program of China(Grant No.2014CB643702)the National Natural Science Foundation of China(Grant No.51590880)+1 种基金the Knowledge Innovation Project of the Chinese Academy of Sciences(Grant No.KJZD-EW-M05)the National Key Research and Development Program of China(Grant No.2016YFB0700903)
文摘Data-mining techniques using machine learning are powerful and efficient for materials design, possessing great potential for discovering new materials with good characteristics. Here, this technique has been used on composition design for La（Fe,Si/Al）（13）-based materials, which are regarded as one of the most promising magnetic refrigerants in practice. Three prediction models are built by using a machine learning algorithm called gradient boosting regression tree（GBRT） to essentially find the correlation between the Curie temperature（TC）, maximum value of magnetic entropy change（（？SM）（max））,and chemical composition, all of which yield high accuracy in the prediction of TC and（？SM）（max）. The performance metric coefficient scores of determination（R^2） for the three models are 0.96, 0.87, and 0.91. These results suggest that all of the models are well-developed predictive models on the challenging issue of generalization ability for untrained data, which can not only provide us with suggestions for real experiments but also help us gain physical insights to find proper composition for further magnetic refrigeration applications.
基金This work was supported by the National Natural Science Foundation of China(No.51571033,11804022)the Science and Technology on Transient Impact Laboratory Foundation(No.6142606183208).
文摘A facile and economical approach was developed for the large-scale production of powdered core-shell structured PTFE/Al (CS-PA) energetic materials through ultrasonic-assisted mixing. The low-cost micrometer-sized PTFE and Al particles were used as starting materials. Under high-power ultrasonic waves, the PTFE powder was dispersed into nano-to sub-micrometer-sized particles and then encapsulated the Al microparticles to form the core-shell structure. The heat of combustion, burning rate, and pressurization rate of the powdered CS-PA were measured. The thermal-initiated reaction behavior was further evaluated using thermogravimetry-differential scanning calorimetry. Subsequently, the bulk CS-PA with a uniform microstructure was obtained via cold isostatic pressing of the powdered CS-PA followed by vacuum sintering. For the bulk CS-PA, the quasi-static compression behavior was characterized, and the impact-initiated reaction processes were conducted using the Split Hopkinson Pressure Bar (SHPB) and evaluated by a high-speed camera. Compared to physically mixed PTFE/Al materials, the powdered and bulk CS-PA demonstrated enhanced thermal- and impact-initiated reaction characteristics respectively, proving the effectiveness of our approach for constructing core-shell structures.
基金National Natural Science Foundation of China[grant number U1730112],China.
文摘In this paper,the ballistic impact experiments,including impact test chamber and impact double-spaced plates,were conducted to study the reaction behaviors of a novel functionally graded reactive material(FGRM),which was composed of polytetrafluoroethylene/aluminum(PTFE/Al)and PTFE/Al/bismuth trioxide(Bi_(2)O_(3)).The experiments showed that the impact direction of the FGRM had a significant effect on the reaction.With the same impact velocity,when the first impact material was PTFE/Al/Bi_(2)O_(3),compared with first impact material PTFE/Al,the FGRM induced higher overpressure in the test chamber and larger damaged area of double-spaced plates.The theoretical model,which considered the shock wave generation and propagation,the effect of the shock wave on reaction efficiency,and penetration behaviors,was developed to analyze the reaction behaviors of the FGRM.The model predicted first impact material of the FGRM with a higher shock impedance was conducive to the reaction of reactive materials.The conclusion of this study provides significant information about the design and application of reactive materials.
基金supported by the National Natural Science Foundation of China(No.50871025)
文摘Five-layered Al/Al-Cu functionally graded material （FGM） was prepared by powder metallurgy technology, and the subsequent heat treatment was carried out for the graded material. The microstructures and distribution of Cu element under pressure sintering （F）, solution treatment （T4） and artificial aging treatment （T6） were investigated, and the Vickers hardness and flexural properties of different states were tested. The results showed that sintered compact with dense structure and compositional continuous change was obtained. The second-phase CuAl 2 was dispersively distributed along grain boundary of Al matrix. After solution treatment at 503 C for 3 h, CuAl 2 phase obviously decreased and dissolved into the Al matrix, and the flexural strength was thereupon enhanced to 228.5 MPa. With the subsequent aging treatment at 150 C for 15 h, the majority of flake shaped precipitates θ phases were uniformly distributed in the matrix. And the distribution of Cu element became gradual continuous compared to sintered compact. Meanwhile, the flexural strength increased further, which accompanied with the decline of plasticity.
基金the National Natural Science Foundation of China(Grant No.50075019)the Visiting Scholar Foundation of Key Lab.in University of China
文摘Microstructure and interracial reactions of Al2O3 joints brazed with Al2O3-particulate-contained composite Ag-Cu-Ti filler material were researched by scanning electron microscopy(SEM),electron probe microscopy analysis(EPMA),energy dispersive spectroscopy(EDS)and X-ray diffraction(XRD).The interracial reaction layer thickness of joints brazed with conventional active filler metal and active composite filler materials with different volume fraction of Al2O3 particulate was also studied.The experimental results indicated although there were Al2O3 particulates added into active filler metals,the time dependence of interracial layer growth of joints brazed with active composite filler material is t^1/2 as described by Fickian law as the joints brazed with conventional active filler metal.
基金financially supported by the National Natural Science Foundation of China(No.51771194)the CNNC Science Fund for Talented Young Scholars,the LingChuang Research Project of China National Nuclear Corporation,the LiaoNing Revitalization Talents Program(No.XLYC1902058)the IMR Innovation Fund(Nos.2021-ZD02 and 2021-PY12)。
文摘B4C reinforced Al composites are widely used as neutron absorbing materials(NAMs)due to excellent neutron absorbing efficiency,however,such NAMs exhibit poor high-temperature properties.To meet the requirement for structure-function integration,NAMs with enhanced high-temperature mechanical properties are desired.In this work,a novel(B4 C+Al_(2)O_(3))/Al NAM with netlike distribution of Al_(2)O_(3)was fabricated by powder metallurgy method and subjected to high-temperature tensile creep test.It was shown that the creep resistance was enhanced by several orders of magnitude via the addition of only2.1 vol.%netlike-distributed Al_(2)O_(3).(B_(4)C+Al_(2)O_(3))/Al exhibited high apparent stress exponents ranging from 16 to 25 and high apparent activation energy of 364 kJ/mol.The creep behaviour could be rationalized using the substructure-invariant model and its rupture behaviour could be described by the Dobes-Milicka equation.
文摘Ti1Al2O3 Functionally Gradient Material (FGM) was prepared by an explosive compaction/SHS process. Ten sheets of the compounding powder were laminated and pressed to get a green body of FGM. It was then compacted explosively By burying the explosive compaction body into a stoichiometric Al/TiO2 mixture and igniting the combustion of the stoichiometric Al/TiO2 mixture, the SHS reaction of the explosive compaction body was initiated by the heat released from the combustion of the stoichiometric Al/TiO2 mixture. In this way, Ti/Al2O3 FGM was synthesized. The adiabatic temperatures of each gradient layer were calculated when the preheating temperatures were 298 K and 1173 K, respectively The microstructure, composition and properties of Ti/Al2O3 FGM and the reaction mechanism of each gradient layer were studied. It was found that Ti/Al2O3 FGM prepared by the explosive compaction/SHS process had a high density and a high microhardness. Its structure, composition and properties showed apparent gradient distribution. The structure of the standard stoichiometric ratio gradient layer of FGM was a network structure. Its reaction mode could be described as follows: Al powder melted first, then the molten Al penetrated into the TiO2 zone and reacted with TiO2, and big pores were left in the original positions of Al powder. The reaction of gradient layers with the addition of Al3O3 as diluents was similar to that of the standard stoichiometric ratio gradient layer, so were their structure and composition. However, the reaction of gradient layers with the addition of Ti as diluents was more complex and the composition deviated slightly from the designed one
文摘The lanthanum aluminum mesoporous materials were synthesized using sodium dodecyl sulfate as a template agent by ultrasonic hydrothermal method.The resulting samples were characterized by low angle X-ray diffraction（XRD）,N2 adsorption-desorption studies,transmission electron microscopy（TEM）and surface morphology analysis（SEM）,surface acid（NH3-TPD）,reducibility properties（TPR）,X-ray energy dispersive spectrometer（EDS）and thermogravimetric analysis（TG/DTG）.A l/La composite mesoporous material were synthesized with n（Al）︰n（La）=70︰1.0,80°C of reaction temperature,20 h of reaction time,12 h of crystallization time,650°C of calcination temperature.The specific surface area of the sample is 273.90 m 2 ·g ？1 ,with the average diameter 5.642 nm and pore volume 0.2354 cm 3 ·g ？1 .The samples have mesoporous structure and its particles are similar to a worm-shaped tubular structure.The influence of calcination temperature on the surface physical and chemical properties of Al/La composited mesoporous materials was examined,and the results showed that the acid strength was increased but the amount of acidic sites is decreased as the calcination temperature increased.It was found that the sample calcined at 650°C had appropriate acid content,acid strength and better reducibility.
基金supported by National Natural Science Foundation of China (Grant No. 50435020)Shandong Provincial Postdoctoral Foundation of China (Grant No. 200703080)
文摘Accurate material constitutive model is considered highly necessary to perform finite element simulation and analysis.However,it is difficult to establish the material constitutive model because of uncertainty of mathematical relationship and constraint of existing experimental condition.At present,there exists considerable gap between finite element simulation result and actual cutting process.Particular emphases were put on investigating the correlation between ＂single factor＂ material constitutive model parameters and temperature for Ti6Al4V alloy,and also establishment of material constitutive model for this kind of material.Theoretical analyses based on dislocation theory and material functional relations showed that material model was deeply affected by variation temperature.By the least squares best fit to the available quasi-static and high-speed impact compression experiment data,material parameters at various temperatures were found.Experimental curves analyses and material parameters comparison showed that the ＂single factor＂ material constitutive model parameters were temperature dependent.Using the mathematical mapping between material parameters and temperature,＂single factor＂ material constitutive model of Ti6Al4V alloy was established,which was proven to be right by comparing with experimental measurements.This work makes clear that the ＂single factor＂ material constitutive model parameters of Ti6Al4V alloy are temperature dependent.At the same time,an accurate material constitutive model is established,which helps to optimize cutting process and control machining distortion for Ti6Al4V alloy aerospace parts.
基金supported by the National Natural Science Foundation of China(Grant No.51475104,51435004)the National Basic Research Program of China(2013CB035500)
文摘The microstructure and mechanical properties of steel/Al structure material produced by additive manufacturing （AM） was investigated in this work based on the cold metal transfer welding. The results show that the microstructure gradually changed from the steel side to the aluminum side. The microstructure in the steel layer consisted of vermiform like ferrite and anstenite structure, while in the aluminum layer the microstructure was constituted by c^-A1 grains and typical reticulate distributive Al-Si eutectic structure. Besides, a 7 y.m thickness Ni-Al intermetallic compound layer was emerged at the interface of nickel and aluminum layer. The maximum room-temperature tensile strength of the Steel-Al structure materials was found to be 54 MPa, the rupture morphology showed a brittle fracture characteristic.
