In this study, the mechanical properties of aluminum-5%magnesium doped with rare earth metal neodymium were evaluated. Fuzzy logic (FL) and artificial neural network (ANN) were used to model the mechanical properties ...In this study, the mechanical properties of aluminum-5%magnesium doped with rare earth metal neodymium were evaluated. Fuzzy logic (FL) and artificial neural network (ANN) were used to model the mechanical properties of aluminum-5%magnesium (0-0.9 wt%) neodymium. The single input (SI) to the fuzzy logic and artificial neural network models was the percentage weight of neodymium, while the multiple outputs (MO) were average grain size, ultimate tensile strength, yield strength elongation and hardness. The fuzzy logic-based model showed more accurate prediction than the artificial neutral network-based model in terms of the correlation coefficient values (R).展开更多
Microstructures of three kinds of typical product states for commercially fabricated alloy 2195 were observed.It is found that the hot-rolled plate is characterized by a fibrous structure containing fine,polygonized s...Microstructures of three kinds of typical product states for commercially fabricated alloy 2195 were observed.It is found that the hot-rolled plate is characterized by a fibrous structure containing fine,polygonized substructures;and the cold-rolled sheet was characterized by a "pan-caked" grain structure containing high density dislocation cells.The product under near peak-aging temper is proved to contain a large amount of dispersive,plate-shaped T1(Al2CuLi) precipitates,together with a small fraction of θ'(Al2Cu) plates,exhibiting a desirable combination of mechanical properties.Analyses using scanning electron microscopy reveal that many coarse,irregular-shaped Al7Cu2Fe constituent particles exist in all product states,which indicates that intermediate heat treatments have little influence on this iron-caused,detrimental phase.The formation and evolution of microstructures for different product states of alloy 2195 were discussed in view point of the commercial production condition.展开更多
The corrosion behaviors of 1420 and 2195 Al-Li alloys under 308 and 490 MPa tensile stress respectively in neutral 3.5% NaCl solution were investigated using electrochemical impedance spectroscopy(EIS) and scanning el...The corrosion behaviors of 1420 and 2195 Al-Li alloys under 308 and 490 MPa tensile stress respectively in neutral 3.5% NaCl solution were investigated using electrochemical impedance spectroscopy(EIS) and scanning electron microscope(SEM). It is found that the unstressed 1420 alloy is featured with large and discrete pits, while general corrosion and localized corrosion including intergranular corrosion and pitting corrosion occur on the unstressed 2195 alloy. As stress is applied to 1420 alloy, the pit becomes denser and its size is decreased. While, for the stressed 2195 alloy, intergranular corrosion is greatly aggravated and severe general corrosion is developed from connected pits. The EIS analysis shows that more severe general corrosion and localized corrosion occur on the stressed 2195 Al-Li alloy than on 1420 Al-Li alloy. It is suggested that tensile stress has greater effect on the corrosion of 2195 Al-Li alloy than on 1420 Al-Li alloy.展开更多
2198 and 5A90 Al-Li alloys were anodized with a constant DC potential in 18%H_2SO_4solution(Solu.A) and the mixture solution of 18%H_2SO_4+5%C_2H_2O_4(Solu.B) at room temperature. 12 and 11 V was optimized as the appl...2198 and 5A90 Al-Li alloys were anodized with a constant DC potential in 18%H_2SO_4solution(Solu.A) and the mixture solution of 18%H_2SO_4+5%C_2H_2O_4(Solu.B) at room temperature. 12 and 11 V was optimized as the applied oxidation potential for 2198 and 5A90 alloys, respectively. Cross-sectional morphology, surface morphology and elements distribution of anodic oxidation coatings were observed by scanning electron microscope equipped with energy dispersive X-ray analysis(SEM/EDX). Corrosion resistance was tested by potentiodynamic polarization plot in 3.5%NaCl solution. The results showed that the thicknesses of coatings obtained at the selected potential in Solu.A and Solu.B were about 50 μm/110 μm for 2198 alloy and 80 μm/110 μm for 5A90 alloy. In both solutions, anodic oxidation coatings of 2198 alloy were primarily composed of Al oxides; those of 5A90 alloy were mainly consisted of Al oxides and a small amount of Mg oxides. The results of potentiodynamic polarization showed that anodic oxidation coatings of 2198 and 5A90 Al-Li alloys had better corrosion resistances than that of untreated alloys.展开更多
The evolution of the grain structures in AA2195 Al-Li alloy plate warm-rolled by 80% reduction during recrystallization annealing at 500 ℃ was investigated by electron backscatter diffraction, scanning electron micro...The evolution of the grain structures in AA2195 Al-Li alloy plate warm-rolled by 80% reduction during recrystallization annealing at 500 ℃ was investigated by electron backscatter diffraction, scanning electron microscopy and transmission electron microscopy. It is found that the elongated grain structures are caused by the lamellar distribution of recrystallization nucleation sites, being lack of large second phase particles (>1 μm), and dispersive coherent particles (such as δ′ and β′) concentrated in planar bands. The recrystallization process may be separated into three stages: firstly, recrystallization nucleation occurs heterogeneously, and the nuclei are concentrated in some planar zones parallel to rolling plane. Secondly, the grain boundaries interacted with small particles concentrate in planar bands, which is able to result in the elongated grain structures. The rate of the grain growth is controlled by the dissolution of these small particles. Thirdly, after most of small particles are dissolved, their hindrance to migration of the grain boundaries fades away, and the unrecrystallized zones are consumed by adjacent recrystallized grains. The migration of high angle grain boundaries along normal direction leads a gradual transformation from the elongated grains to the nearly equiaxed, which is driven by the tension of the grain boundaries.展开更多
Grain refinement can offer significant benefits to both continuous casting and cast to shape products, and Al5Ti1B master alloy containing mainly TiAl 3 and TiB 2 particles in Al matrix has been proven to perform well...Grain refinement can offer significant benefits to both continuous casting and cast to shape products, and Al5Ti1B master alloy containing mainly TiAl 3 and TiB 2 particles in Al matrix has been proven to perform well for giving the best refinement, but the working method of adding Al5Ti1B rod to the furnace during casting are often related to solid deformation, and melt vibration may help to reduce the size of TiAl 3 and improve the distribution of TiB 2. Therefore the effects of solid deformation and melt vibration on the structures and refinement performance of Al5Ti1B master alloys were studied. The experimental results show that both solid deformation and melt vibration can improve the distribution of TiB 2 in Al5Ti1B master alloys, increase the interface energy and nucleation activity of TiB 2 particles. In the meantime, solid deformation can store deformation energy and melt vibration can break fragile plate like TiAl 3 compounds. So both methods can improve the refinement effectiveness of Al5Ti1B master alloys.展开更多
The creep-rupture behavior of an ageing hardened Al-Li-Cu -Mg-Zr alloy has been investigated at 463~563 K. Results indicate that creep rupture life is associated with the coarsening of precipitates,the precipitation...The creep-rupture behavior of an ageing hardened Al-Li-Cu -Mg-Zr alloy has been investigated at 463~563 K. Results indicate that creep rupture life is associated with the coarsening of precipitates,the precipitation of equilibrium phases and the formatio展开更多
The fracture mechanism for Al-2.5Li-1.3Cu-0.9Mg-0.13Zr alloy is quite different from undergone various regimes of heat treatment.With the decrease of solution temperature and the increase of aging temperature,the inte...The fracture mechanism for Al-2.5Li-1.3Cu-0.9Mg-0.13Zr alloy is quite different from undergone various regimes of heat treatment.With the decrease of solution temperature and the increase of aging temperature,the intergranular delamination and necking fracture on the fracture surface increase and the shearing facture decreases.Thus,the toughness of the alloy may be much improved.展开更多
The microstructure and tensile properties of Al-2. 15Li-1 .28Mg-1 .26Cu-0. 10 Zr alloy processed by a spray deposition processing have been investigated, and experimental results show that the as-deposited Al-Li alloy...The microstructure and tensile properties of Al-2. 15Li-1 .28Mg-1 .26Cu-0. 10 Zr alloy processed by a spray deposition processing have been investigated, and experimental results show that the as-deposited Al-Li alloy has a very fine equiaxed grain structure with a relative density of 94±3% on average. Grains in the as-extruded alloy are "brick-like" in morphology, and little oxide particles have been found at the grain boundaries. δ’ particles with irregular shape and, "δ’-β’" co-precipitates precipitate in the aged alloy. S’ phase also precipitate homogeneously at the dislocations. The spray deposited Al-Li alloy has the best properties (σb = 508MPa, σ0.2 = 420MPa, δ=12%) at the peak aged condition. Compared with RS/PM Al-Li alloy, ductility of the tested alloy has been enhanced obviously while a comparable tensile strength is maintained.展开更多
Lithium metal has gained extensive attention as the most ideal candidate for next-generation battery anode owing to the ultrahigh specific capacity and the lowest electrochemical potential.However,uncontrollable dendr...Lithium metal has gained extensive attention as the most ideal candidate for next-generation battery anode owing to the ultrahigh specific capacity and the lowest electrochemical potential.However,uncontrollable dendrite growth and huge volume variation extremely restrict the future deployment of lithium metal batteries.Herein,we report metal chalcogenide SnSSe with unique nanoplate stacking structure as a robust substrate for stable Li metal anode.During the initial Li plating process,lithiophilic Li_(22)Sn_(5) alloy and Li_(2)S/Li_(2)Se sites are obtained via in-situ electrochemical reaction of Li metal and SnSSe.Density functional theory(DFT)calculation demonstrates that the formed Li_(2)S/Li_(2)Se achieves low Li diffusion energy barrier,ensuring rapid Li~+migration.Li_(22)Sn_(5) alloy provides strong nucleation sites,promoting uniform Li nucleation.Furthermore,in-situ optical microscopy analysis suggests that the synthesized effect fundamentally inhibits lithium dendrite growth.Consequently,SnSSe modified Cu foil delivered an ultralow nucleation overpotential,superior cycling stability with 450 cycles(Coulombic efficiency,>98%),and excellent plating/stripping behavior over 2200 h at 0.5 mA cm^(-2).Moreover,the brilliant reversible cycles and rate capability were also realized in Li@SnSSe//LiFePO_(4)(LFP)full cell,shedding light on the feasibility of SnSSe for stable and dendrite-free lithium metal anode.展开更多
文摘In this study, the mechanical properties of aluminum-5%magnesium doped with rare earth metal neodymium were evaluated. Fuzzy logic (FL) and artificial neural network (ANN) were used to model the mechanical properties of aluminum-5%magnesium (0-0.9 wt%) neodymium. The single input (SI) to the fuzzy logic and artificial neural network models was the percentage weight of neodymium, while the multiple outputs (MO) were average grain size, ultimate tensile strength, yield strength elongation and hardness. The fuzzy logic-based model showed more accurate prediction than the artificial neutral network-based model in terms of the correlation coefficient values (R).
基金Projects(U22A20190, 52175373, 52005516) supported by the National Natural Science Foundation of ChinaProject(ZZYJKT2021-03) supported by the State Key Laboratory of High Performance Complex Manufacturing,Central South University,ChinaProject(2020RC4001) supported by the Science and Technology Innovation Program of Hunan Province,China。
基金supported by the National Key Technologies R&D Program of China during the 10th Five-year Plan Period
文摘Microstructures of three kinds of typical product states for commercially fabricated alloy 2195 were observed.It is found that the hot-rolled plate is characterized by a fibrous structure containing fine,polygonized substructures;and the cold-rolled sheet was characterized by a "pan-caked" grain structure containing high density dislocation cells.The product under near peak-aging temper is proved to contain a large amount of dispersive,plate-shaped T1(Al2CuLi) precipitates,together with a small fraction of θ'(Al2Cu) plates,exhibiting a desirable combination of mechanical properties.Analyses using scanning electron microscopy reveal that many coarse,irregular-shaped Al7Cu2Fe constituent particles exist in all product states,which indicates that intermediate heat treatments have little influence on this iron-caused,detrimental phase.The formation and evolution of microstructures for different product states of alloy 2195 were discussed in view point of the commercial production condition.
基金Project(50401012) supported by the National Natural Science Foundation of China
文摘The corrosion behaviors of 1420 and 2195 Al-Li alloys under 308 and 490 MPa tensile stress respectively in neutral 3.5% NaCl solution were investigated using electrochemical impedance spectroscopy(EIS) and scanning electron microscope(SEM). It is found that the unstressed 1420 alloy is featured with large and discrete pits, while general corrosion and localized corrosion including intergranular corrosion and pitting corrosion occur on the unstressed 2195 alloy. As stress is applied to 1420 alloy, the pit becomes denser and its size is decreased. While, for the stressed 2195 alloy, intergranular corrosion is greatly aggravated and severe general corrosion is developed from connected pits. The EIS analysis shows that more severe general corrosion and localized corrosion occur on the stressed 2195 Al-Li alloy than on 1420 Al-Li alloy. It is suggested that tensile stress has greater effect on the corrosion of 2195 Al-Li alloy than on 1420 Al-Li alloy.
基金Funded by the Aeronautical Science Foundation of China(No.2015ZE54035)the National Natural Science Foundation of China(No.51301113)
文摘2198 and 5A90 Al-Li alloys were anodized with a constant DC potential in 18%H_2SO_4solution(Solu.A) and the mixture solution of 18%H_2SO_4+5%C_2H_2O_4(Solu.B) at room temperature. 12 and 11 V was optimized as the applied oxidation potential for 2198 and 5A90 alloys, respectively. Cross-sectional morphology, surface morphology and elements distribution of anodic oxidation coatings were observed by scanning electron microscope equipped with energy dispersive X-ray analysis(SEM/EDX). Corrosion resistance was tested by potentiodynamic polarization plot in 3.5%NaCl solution. The results showed that the thicknesses of coatings obtained at the selected potential in Solu.A and Solu.B were about 50 μm/110 μm for 2198 alloy and 80 μm/110 μm for 5A90 alloy. In both solutions, anodic oxidation coatings of 2198 alloy were primarily composed of Al oxides; those of 5A90 alloy were mainly consisted of Al oxides and a small amount of Mg oxides. The results of potentiodynamic polarization showed that anodic oxidation coatings of 2198 and 5A90 Al-Li alloys had better corrosion resistances than that of untreated alloys.
基金Project (2004053304) supported by the Doctral Program Foundation of Education Ministry of China Projects(50231030, 50301016) supported by the National Natural Science Foundation of China
文摘The evolution of the grain structures in AA2195 Al-Li alloy plate warm-rolled by 80% reduction during recrystallization annealing at 500 ℃ was investigated by electron backscatter diffraction, scanning electron microscopy and transmission electron microscopy. It is found that the elongated grain structures are caused by the lamellar distribution of recrystallization nucleation sites, being lack of large second phase particles (>1 μm), and dispersive coherent particles (such as δ′ and β′) concentrated in planar bands. The recrystallization process may be separated into three stages: firstly, recrystallization nucleation occurs heterogeneously, and the nuclei are concentrated in some planar zones parallel to rolling plane. Secondly, the grain boundaries interacted with small particles concentrate in planar bands, which is able to result in the elongated grain structures. The rate of the grain growth is controlled by the dissolution of these small particles. Thirdly, after most of small particles are dissolved, their hindrance to migration of the grain boundaries fades away, and the unrecrystallized zones are consumed by adjacent recrystallized grains. The migration of high angle grain boundaries along normal direction leads a gradual transformation from the elongated grains to the nearly equiaxed, which is driven by the tension of the grain boundaries.
文摘Grain refinement can offer significant benefits to both continuous casting and cast to shape products, and Al5Ti1B master alloy containing mainly TiAl 3 and TiB 2 particles in Al matrix has been proven to perform well for giving the best refinement, but the working method of adding Al5Ti1B rod to the furnace during casting are often related to solid deformation, and melt vibration may help to reduce the size of TiAl 3 and improve the distribution of TiB 2. Therefore the effects of solid deformation and melt vibration on the structures and refinement performance of Al5Ti1B master alloys were studied. The experimental results show that both solid deformation and melt vibration can improve the distribution of TiB 2 in Al5Ti1B master alloys, increase the interface energy and nucleation activity of TiB 2 particles. In the meantime, solid deformation can store deformation energy and melt vibration can break fragile plate like TiAl 3 compounds. So both methods can improve the refinement effectiveness of Al5Ti1B master alloys.
文摘The creep-rupture behavior of an ageing hardened Al-Li-Cu -Mg-Zr alloy has been investigated at 463~563 K. Results indicate that creep rupture life is associated with the coarsening of precipitates,the precipitation of equilibrium phases and the formatio
文摘The fracture mechanism for Al-2.5Li-1.3Cu-0.9Mg-0.13Zr alloy is quite different from undergone various regimes of heat treatment.With the decrease of solution temperature and the increase of aging temperature,the intergranular delamination and necking fracture on the fracture surface increase and the shearing facture decreases.Thus,the toughness of the alloy may be much improved.
文摘The microstructure and tensile properties of Al-2. 15Li-1 .28Mg-1 .26Cu-0. 10 Zr alloy processed by a spray deposition processing have been investigated, and experimental results show that the as-deposited Al-Li alloy has a very fine equiaxed grain structure with a relative density of 94±3% on average. Grains in the as-extruded alloy are "brick-like" in morphology, and little oxide particles have been found at the grain boundaries. δ’ particles with irregular shape and, "δ’-β’" co-precipitates precipitate in the aged alloy. S’ phase also precipitate homogeneously at the dislocations. The spray deposited Al-Li alloy has the best properties (σb = 508MPa, σ0.2 = 420MPa, δ=12%) at the peak aged condition. Compared with RS/PM Al-Li alloy, ductility of the tested alloy has been enhanced obviously while a comparable tensile strength is maintained.
基金financially supported by the National Natural Science Foundation of China(52074113,22005091,and 22005092)the Hunan University Outstanding Youth Science Foundation(531118040319)+5 种基金the Science and Technology Innovation Program of Hunan Province(2021RC3055)the Changsha Municipal Natural Science Foundation(kq2014037)the CITIC Metals Ningbo Energy Co.Ltd.(H202191380246)the Chongqing Talents:Exceptional Young Talents Project(CQYC202105015)the Shenzhen Virtual University Park Basic Research Project of Free exploration(2021Szvup036)financially supported by the Graduate Research and Innovation Projects of Hunan Province(QL20210088)。
文摘Lithium metal has gained extensive attention as the most ideal candidate for next-generation battery anode owing to the ultrahigh specific capacity and the lowest electrochemical potential.However,uncontrollable dendrite growth and huge volume variation extremely restrict the future deployment of lithium metal batteries.Herein,we report metal chalcogenide SnSSe with unique nanoplate stacking structure as a robust substrate for stable Li metal anode.During the initial Li plating process,lithiophilic Li_(22)Sn_(5) alloy and Li_(2)S/Li_(2)Se sites are obtained via in-situ electrochemical reaction of Li metal and SnSSe.Density functional theory(DFT)calculation demonstrates that the formed Li_(2)S/Li_(2)Se achieves low Li diffusion energy barrier,ensuring rapid Li~+migration.Li_(22)Sn_(5) alloy provides strong nucleation sites,promoting uniform Li nucleation.Furthermore,in-situ optical microscopy analysis suggests that the synthesized effect fundamentally inhibits lithium dendrite growth.Consequently,SnSSe modified Cu foil delivered an ultralow nucleation overpotential,superior cycling stability with 450 cycles(Coulombic efficiency,>98%),and excellent plating/stripping behavior over 2200 h at 0.5 mA cm^(-2).Moreover,the brilliant reversible cycles and rate capability were also realized in Li@SnSSe//LiFePO_(4)(LFP)full cell,shedding light on the feasibility of SnSSe for stable and dendrite-free lithium metal anode.
基金Project(2013JSJJ0001)supported by the Teachers’ Research Fund,Central South University,ChinaProject supported by the Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center,China