Based on the force-heat equivalence energy density principle,a theoretical model for magnetic metallic materials is developed,which characterizes the temperature-dependent magnetic anisotropy energy by considering the...Based on the force-heat equivalence energy density principle,a theoretical model for magnetic metallic materials is developed,which characterizes the temperature-dependent magnetic anisotropy energy by considering the equivalent relationship between magnetic anisotropy energy and heat energy;then the relationship between the magnetic anisotropy constant and saturation magnetization is considered.Finally,we formulate a temperature-dependent model for saturation magnetization,revealing the inherent relationship between temperature and saturation magnetization.Our model predicts the saturation magnetization for nine different magnetic metallic materials at different temperatures,exhibiting satisfactory agreement with experimental data.Additionally,the experimental data used as reference points are at or near room temperature.Compared to other phenomenological theoretical models,this model is considerably more accessible than the data required at 0 K.The index included in our model is set to a constant value,which is equal to 10/3 for materials other than Fe,Co,and Ni.For transition metals(Fe,Co,and Ni in this paper),the index is 6 in the range of 0 K to 0.65T_(cr)(T_(cr) is the critical temperature),and 3 in the range of 0.65T_(cr) to T_(cr),unlike other models where the adjustable parameters vary according to each material.In addition,our model provides a new way to design and evaluate magnetic metallic materials with superior magnetic properties over a wide range of temperatures.展开更多
An expression of degree of polarization（DOP） for metallic material is presented based on the three-component polarized bidirectional reflectance distribution function（p BRDF） model with considering specular reflec...An expression of degree of polarization（DOP） for metallic material is presented based on the three-component polarized bidirectional reflectance distribution function（p BRDF） model with considering specular reflection, directional diffuse reflection and ideal diffuse reflection. The three-component p BRDF model with a detailed reflection assumption is validated by comparing simulations with measurements. The DOP expression presented in this paper is related to surface roughness, which makes it more reasonable in physics. Test results for two metallic samples show that the DOP based on the three-component p BRDF model accords well with the measurement and the error of existing DOP expression is significantly reduced by introducing the diffuse reflection. It indicates that our DOP expression describes the polarized reflection properties of metallic surfaces more accurately.展开更多
Based on the three-component assumption that the reflection is divided into specular reflection,directional diffuse reflection,and ideal diffuse reflection,a bidirectional reflectance distribution function（BRDF） mod...Based on the three-component assumption that the reflection is divided into specular reflection,directional diffuse reflection,and ideal diffuse reflection,a bidirectional reflectance distribution function（BRDF） model of metallic materials is presented.Compared with the two-component assumption that the reflection is composed of specular reflection and diffuse reflection,the three-component assumption divides the diffuse reflection into directional diffuse and ideal diffuse reflection.This model effectively resolves the problem that constant diffuse reflection leads to considerable error for metallic materials.Simulation and measurement results validate that this three-component BRDF model can improve the modeling accuracy significantly and describe the reflection properties in the hemisphere space precisely for the metallic materials.展开更多
Strong impact does serious harm to the military industries so it is necessary to choose reasonable cushioning material and design effective buffers to prevent the impact of equipment.Based on the capillary property en...Strong impact does serious harm to the military industries so it is necessary to choose reasonable cushioning material and design effective buffers to prevent the impact of equipment.Based on the capillary property entangled porous metallic wire materials(EPMWM),this paper designed a composite buffer which uses EPMWM and viscous fluid as cushioning materials under the low-speed impact of the recoil force device of weapon equipment(such as artillery,mortar,etc.).Combined with the capillary model,porosity,hydraulic diameter,maximum pore diameter and pore distribution were used to characterize the pore structure characteristics of EPMWM.The calculation model of the damping force of the composite buffer was established.The low-speed impact test of the composite buffer was conducted.The parameters of the buffer under low-speed impact were identified according to the model,and the nonlinear model of damping force was obtained.The test results show that the composite buffer with EPMWM and viscous fluid can absorb the impact energy from the recoil movement effectively,and provide a new method for the buffer design of weapon equipment(such as artillery,mortar,etc.).展开更多
Distinct from"rockingchair"lithium-ion batteries(LIBs),the unique anionic intercalation chemistry on the cathode side of dual-ion batteries(DIBs)endows them with intrinsic advantages of low cost,high voltage...Distinct from"rockingchair"lithium-ion batteries(LIBs),the unique anionic intercalation chemistry on the cathode side of dual-ion batteries(DIBs)endows them with intrinsic advantages of low cost,high voltage,and ecofriendly,which is attracting widespread attention,and is expected to achieve the next generation of large-scale energy storage applications.Although the electrochemical reactions on the anode side of DIBs are similar to that of LIBs,in fact,to match the rapid insertion kinetics of anions on the cathode side and consider the compatibility with electrolyte system which also serves as an active material,the anode materials play a very important role,and there is an urgent demand for rational structural design and performance optimization.A review and summarization of previous studies will facilitate the exploration and optimization of DIBs in the future.Here,we summarize the development process and working mechanism of DIBs and exhaustively categorize the latest research of DIBs anode materials and their applications in different battery systems.Moreover,the structural design,reaction mechanism and electrochemical performance of anode materials are briefly discussed.Finally,the fundamental challenges,potential strategies and perspectives are also put forward.It is hoped that this review could shed some light for researchers to explore more superior anode materials and advanced systems to further promote the development of DIBs.展开更多
Composite materials exhibit the impressive mechanical properties of high damping and stiffness,which cannot be attained by employing conventional single materials.Along these lines,a novel material architecture is pre...Composite materials exhibit the impressive mechanical properties of high damping and stiffness,which cannot be attained by employing conventional single materials.Along these lines,a novel material architecture is presented in this work in order to fabricate composites with enhanced mechanical characteristics.More specifically,entangled metallic wire materials were used as the active matrix,whereas polyurethane was employed as the reinforcement elements.As a result,an entangled metallic wire material-polyurethane composite with high damping and stiffness was prepared by enforcing the vacuum infiltration method.On top of that,the mechanical properties(loss factor,energy consumption,and average stiffness)of the proposed composite materials were characterized by performing dynamic tests,and its fatigue characteristics were verified by the micro-interface bonding,as well as the macro-damage factor.The impact of the density,preloading spacing,loading amplitude,and exciting frequency on the mechanical properties of the composites were also thoroughly analyzed.The extracted results indicate that the mechanical properties of the composites were significantly enhanced than those of the pure materials due to the introduction of interface friction.Moreover,the average stiffness of the composites was about 10 times the respective value of the entangled metallic wire material.Interestingly,a rise in the loading period leads to some failure between the composite interfaces,which reduces the stiffness property but enhances the damping dissipation properties.Finally,a comprehensive dynamic mechanical model of the composites was established,while it was experimentally verified.The proposed composites possess higher damping features,i.e.,stiffness characteristics,and maintain better fatigue characteristics,which can broaden the application range of the composites.In addition,we provide a theoretical and experimental framework for the research and applications in the field of metal matrix composites.展开更多
Entangled porous metallic wire material(EPMWM)has the potential as a thermal insulation material in defence and engineering.In order to optimize its thermophysical properties at the design stage,it is of great signifi...Entangled porous metallic wire material(EPMWM)has the potential as a thermal insulation material in defence and engineering.In order to optimize its thermophysical properties at the design stage,it is of great significance to reveal the thermal response mechanism of EPMWM based on its complex structural effects.In the present work,virtual manufacturing technology(VMT)was developed to restore the physics-based 3D model of EPMWM.On this basis,the transient thermal analysis is carried out to explore the contact-relevant thermal behavior of EPMWM,and then the spiral unit containing unique structural information are further extracted and counted.In particular,the thermal resistance network is numerically constructed based on the spiral unit through the thermoelectric analogy method to accurately predict the effective thermal conductivity(ETC)of EPMWM.Finally,the thermal diffusivity and specific heat of the samples were obtained by the laser thermal analyzer to calculate the ETC and thermal insulation factor of interest.The results show that the ETC of EPMWM increases with increasing temperature or reducing density under the experimental conditions.The numerical prediction is consistent with the experimental result and the average error is less than 4%.展开更多
To improve the defense capability of military equipment under extreme conditions,impact-resistant and high-energy-consuming materials have to be developed.The damping characteristic of entangled porous metallic wire m...To improve the defense capability of military equipment under extreme conditions,impact-resistant and high-energy-consuming materials have to be developed.The damping characteristic of entangled porous metallic wire materials(EPMWM)for vibration isolation was previously investigated.In this paper,a study focusing on the impact-resistance of EPMWM with the consideration of ambient temperature is presented.The quasi-static and low-velocity impact mechanical behavior of EPMWM under different temperatures(25℃-300℃)are systematically studied.The results of the static compression test show that the damping energy dissipation of EPMWM increases with temperature while the nonlinear damping characteristics are gradually enhanced.During the impact experiments,the impact energy loss rate of EPMWM was between 65%and 85%,while the temperatures increased from 25℃to 300℃.Moreover,under the same drop impact conditions,the overall deformation of EPMWM decreases in the temperature range of 100℃-200℃.On the other hand,the impact stiffness,energy dissipation,and impact loss factor of EPMWM significantly increase with temperature.This can be attributed to an increase in temperature,which changes the thermal expansion coefficient and contact state of the internal wire helixes.Consequently,the energy dissipation mode(dry friction,air damping,and plastic deformation)of EPMWM is also altered.Therefore,the EPMWM may act as a potential candidate material for superior energy absorption applications.展开更多
In this study,the interactions between a Ga-based liquid metal,GaInSn,and several metal materials,including pure metals(Ni and Ti)and alloys(316H stainless steel(SS)and GH3535),at 650℃were investigated.The aim was to...In this study,the interactions between a Ga-based liquid metal,GaInSn,and several metal materials,including pure metals(Ni and Ti)and alloys(316H stainless steel(SS)and GH3535),at 650℃were investigated.The aim was to evaluate the corrosion performance and select a suitable candidate material for use as a molten salt manometer diaphragm in thermal energy storage systems.The results indicated that the alloys(316H SS and GH3535)exhibited less corrosion than pure metals(Ni and Ti)in liquid GaInSn.Ga-rich binary intermetallic compounds were found to form on the surfaces of all the tested metal materials exposed to liquid GaInSn,as a result of the decomposition of liquid GaInSn and its reaction with the constituent elements of the metal materials.The corrosion mechanism for all the tested materials exposed to liquid GaInSn was also investigated and proposed,which may aid in selecting the optimal candidate material when liquid GaInSn is used as the pressure-sensing medium.展开更多
Additive manufacturing(AM), or 3D printing, is an emerging technology that “adds” materials up and constructs products through a layer-by-layer procedure. Laser powder bed fusion(LPBF) is a powder-bed-based AM techn...Additive manufacturing(AM), or 3D printing, is an emerging technology that “adds” materials up and constructs products through a layer-by-layer procedure. Laser powder bed fusion(LPBF) is a powder-bed-based AM technology that can fabricate a large variety of metallic materials with excellent quality and accuracy. However, various defects such as porosity,cracks, and incursions can be generated during the printing process. As the most universal and a near-inevitable defect,porosity plays a substantial role in determining the mechanical performance of as-printed products. This work presents a comprehensive review of literatures that focused on the porosity in LPBF printed metals. The formation mechanisms,evaluation methods, effects on mechanical performance with corresponding models, and controlling methods of porosity have been illustrated and discussed in-depth. Achievements in four representative metals, namely Ti-6Al-4V, 316L, Inconel 718, and Al Si10Mg, have been critically reviewed with a statistical analysis on the correlation between porosity fraction and tensile properties. Ductility has been determined as the most sensitive property to porosity among several key tensile properties. This review also provides potential directions and opportunities to address the current porosity-related challenges.展开更多
The precipitation of MgZn2 phase in aging process of Al-Zn-Mg-Cu alloy forging was characterized qualitatively after transmission electron microscope(TEM)observation,X-ray diffraction phase analysis and the exact meas...The precipitation of MgZn2 phase in aging process of Al-Zn-Mg-Cu alloy forging was characterized qualitatively after transmission electron microscope(TEM)observation,X-ray diffraction phase analysis and the exact measure of lattice parameter.And,the precipitation of the second-phase in aging process was simulated after test the resistivity of the alloy in a continuous heating process and delayed time processing.The results show that when heating in the same rate,the alloy resistivity increases with temperature first,a mutation point appears at 110℃,and the resistivity reaches its peak at 120℃.Then,the resistivity decreases and achieves a minimum at about 170℃.Afterwards,it increases again.The change of resistivity results from a combined effect of the temperature and phase transformation.The volume precipitation of η' phase dominates at about 120℃,and the resistivity of forgings decreases accordingly.When the specimen cools in a furnace at 240℃,the phase transformation finishes basically and the alloy content of Al-matix keeps stable,thus,the alloy resistivity depends on the temperature only.It decreases with temperature and time since the end of precipitation.The higher the temperature is,the bigger it will be.With a big descending rate of the resistivity curve,the time to reach the stable value becomes shorter.展开更多
Lithium-ion hybrid supercapacitors （LIHSs）, also called Li-ion capacitors, are electrochemical energy stor- age devices that combining the advantages of high power density of supercapacitor and high energy density o...Lithium-ion hybrid supercapacitors （LIHSs）, also called Li-ion capacitors, are electrochemical energy stor- age devices that combining the advantages of high power density of supercapacitor and high energy density of Li-ion battery. However, high power density and long cycle life are still challenges for the cul~ rent LIHSs due to the imbalance of charge-storage capacity and electrode kinetics between capacitor-type cathode and battery-type anode. Therefore, great efforts have been made on designing novel cathode materials with high storage capacity and anode material with enhanced kinetic behavior for LIHSs. With unique two-dimensional form and numerous appealing properties, for the past several years, the rational designed graphene and its composites materials exhibit greatly improved electrochemical performance as cathode or anode for LIHSs. Here, we summarized and discussed the latest advances of the state- of-art graphene-based materials for LIHSs applications. The major roles of graphene are highlighted as （1） a superior active material, （2） ultrathin 2D flexible support to remedy the sluggish reaction of the metal compound anode, and （3） good 2D building blocks for constructing macroscopic 3D pOFOUS car- bonjgraphene hybrids. In addition, some high performance aqueous LIHSs using graphene as electrode were also summarized. Finally, the perspectives and challenges are also proposed for further develop- ment of more advanced graphene-based LIHSs.展开更多
Electrochemical energy storage systems with high specific energy and power as well as long cyclic stability attract increasing attention in new energy technologies. The principles for rational design of electrodes are...Electrochemical energy storage systems with high specific energy and power as well as long cyclic stability attract increasing attention in new energy technologies. The principles for rational design of electrodes are discussed to reduce the activation, concentration, and resistance overpotentials and improve the active ma- terial efficiency in order to simultaneously achieve high specific energy and power. Three dimensional （3D） nanocomposites are currently considered as promising electrode materials due to their large surface area, reduced electronic and ionic diffusion distances, and synergistic effects. This paper reviews the most recent progress on the synthesis and application of 3D thin film nanoelectrode arrays based on aligned carbon nan- otubes （ACNTs） directly grown on metal foils for energy storages and special attentions are paid on our own representative works. These novel 3D nanoelectrode arrays on metal foil exhibit improved electrochemical performances in terms of specific energy, specific power and cyclic stability due to their unique structures. In this active materials coated ACNTs over conductive substrate structures, each component is tailored to address a different demand. The electrochemical active material is used to store energy, while the ACNTs are employed to provide a large surface area to support the active material and nanocable arrays to facilitate the electron transport. The thin film of active materials can not only reduce ion transport resistance by shorten- ing the diffusion length but also make the film elastic enough to tolerate significant volume changes during charge and discharge cycles. The conductive substrate is used as the current collector and the direct contact of the ACNT arrays with the substrate reduces significantly the contact resistance. The principles obtained from ACNT based electrodes are extended to aligned graphene based electrodes. Similar improvements have been achieved which confirms the reliability of the principles obtained. In addition, we also discuss and view the ongoing trends in development of aligned carbon nanostructures based electrodes for energy storage.展开更多
基金Project supported by the Natural Science Foundation of Chongqing(Grant No.CSTB2022NSCQ-MSX0391)。
文摘Based on the force-heat equivalence energy density principle,a theoretical model for magnetic metallic materials is developed,which characterizes the temperature-dependent magnetic anisotropy energy by considering the equivalent relationship between magnetic anisotropy energy and heat energy;then the relationship between the magnetic anisotropy constant and saturation magnetization is considered.Finally,we formulate a temperature-dependent model for saturation magnetization,revealing the inherent relationship between temperature and saturation magnetization.Our model predicts the saturation magnetization for nine different magnetic metallic materials at different temperatures,exhibiting satisfactory agreement with experimental data.Additionally,the experimental data used as reference points are at or near room temperature.Compared to other phenomenological theoretical models,this model is considerably more accessible than the data required at 0 K.The index included in our model is set to a constant value,which is equal to 10/3 for materials other than Fe,Co,and Ni.For transition metals(Fe,Co,and Ni in this paper),the index is 6 in the range of 0 K to 0.65T_(cr)(T_(cr) is the critical temperature),and 3 in the range of 0.65T_(cr) to T_(cr),unlike other models where the adjustable parameters vary according to each material.In addition,our model provides a new way to design and evaluate magnetic metallic materials with superior magnetic properties over a wide range of temperatures.
文摘An expression of degree of polarization（DOP） for metallic material is presented based on the three-component polarized bidirectional reflectance distribution function（p BRDF） model with considering specular reflection, directional diffuse reflection and ideal diffuse reflection. The three-component p BRDF model with a detailed reflection assumption is validated by comparing simulations with measurements. The DOP expression presented in this paper is related to surface roughness, which makes it more reasonable in physics. Test results for two metallic samples show that the DOP based on the three-component p BRDF model accords well with the measurement and the error of existing DOP expression is significantly reduced by introducing the diffuse reflection. It indicates that our DOP expression describes the polarized reflection properties of metallic surfaces more accurately.
文摘Based on the three-component assumption that the reflection is divided into specular reflection,directional diffuse reflection,and ideal diffuse reflection,a bidirectional reflectance distribution function（BRDF） model of metallic materials is presented.Compared with the two-component assumption that the reflection is composed of specular reflection and diffuse reflection,the three-component assumption divides the diffuse reflection into directional diffuse and ideal diffuse reflection.This model effectively resolves the problem that constant diffuse reflection leads to considerable error for metallic materials.Simulation and measurement results validate that this three-component BRDF model can improve the modeling accuracy significantly and describe the reflection properties in the hemisphere space precisely for the metallic materials.
基金supported by the National Natural Science Foundation of China (Grant No.51805086)。
文摘Strong impact does serious harm to the military industries so it is necessary to choose reasonable cushioning material and design effective buffers to prevent the impact of equipment.Based on the capillary property entangled porous metallic wire materials(EPMWM),this paper designed a composite buffer which uses EPMWM and viscous fluid as cushioning materials under the low-speed impact of the recoil force device of weapon equipment(such as artillery,mortar,etc.).Combined with the capillary model,porosity,hydraulic diameter,maximum pore diameter and pore distribution were used to characterize the pore structure characteristics of EPMWM.The calculation model of the damping force of the composite buffer was established.The low-speed impact test of the composite buffer was conducted.The parameters of the buffer under low-speed impact were identified according to the model,and the nonlinear model of damping force was obtained.The test results show that the composite buffer with EPMWM and viscous fluid can absorb the impact energy from the recoil movement effectively,and provide a new method for the buffer design of weapon equipment(such as artillery,mortar,etc.).
基金financial support provided by the National Natural Science Foundation of China(22075089)the Project of Science and Technology of Jieyang City(2019026)the Fundamental and Applied Fundamental Research Project of Zhuhai City(22017003200023).
文摘Distinct from"rockingchair"lithium-ion batteries(LIBs),the unique anionic intercalation chemistry on the cathode side of dual-ion batteries(DIBs)endows them with intrinsic advantages of low cost,high voltage,and ecofriendly,which is attracting widespread attention,and is expected to achieve the next generation of large-scale energy storage applications.Although the electrochemical reactions on the anode side of DIBs are similar to that of LIBs,in fact,to match the rapid insertion kinetics of anions on the cathode side and consider the compatibility with electrolyte system which also serves as an active material,the anode materials play a very important role,and there is an urgent demand for rational structural design and performance optimization.A review and summarization of previous studies will facilitate the exploration and optimization of DIBs in the future.Here,we summarize the development process and working mechanism of DIBs and exhaustively categorize the latest research of DIBs anode materials and their applications in different battery systems.Moreover,the structural design,reaction mechanism and electrochemical performance of anode materials are briefly discussed.Finally,the fundamental challenges,potential strategies and perspectives are also put forward.It is hoped that this review could shed some light for researchers to explore more superior anode materials and advanced systems to further promote the development of DIBs.
基金National Natural Science Foundation of China(Grant No.52175162,51805086 and 51975123)Natural Science Foundation of Fujian Province(Grant No.2019J01210)Health education joint project of Fujian Province(Grant No.2019-WJ-01)。
文摘Composite materials exhibit the impressive mechanical properties of high damping and stiffness,which cannot be attained by employing conventional single materials.Along these lines,a novel material architecture is presented in this work in order to fabricate composites with enhanced mechanical characteristics.More specifically,entangled metallic wire materials were used as the active matrix,whereas polyurethane was employed as the reinforcement elements.As a result,an entangled metallic wire material-polyurethane composite with high damping and stiffness was prepared by enforcing the vacuum infiltration method.On top of that,the mechanical properties(loss factor,energy consumption,and average stiffness)of the proposed composite materials were characterized by performing dynamic tests,and its fatigue characteristics were verified by the micro-interface bonding,as well as the macro-damage factor.The impact of the density,preloading spacing,loading amplitude,and exciting frequency on the mechanical properties of the composites were also thoroughly analyzed.The extracted results indicate that the mechanical properties of the composites were significantly enhanced than those of the pure materials due to the introduction of interface friction.Moreover,the average stiffness of the composites was about 10 times the respective value of the entangled metallic wire material.Interestingly,a rise in the loading period leads to some failure between the composite interfaces,which reduces the stiffness property but enhances the damping dissipation properties.Finally,a comprehensive dynamic mechanical model of the composites was established,while it was experimentally verified.The proposed composites possess higher damping features,i.e.,stiffness characteristics,and maintain better fatigue characteristics,which can broaden the application range of the composites.In addition,we provide a theoretical and experimental framework for the research and applications in the field of metal matrix composites.
基金National Natural Science Foundation of China(Grant Nos.52175162,51805086 and 51975123)Natural Science Foundation of Fujian Province,China(Grant No.2019J01210)Health Education Joint Project of Fujian Province,China(Grant No.2019-WJ-01).
文摘Entangled porous metallic wire material(EPMWM)has the potential as a thermal insulation material in defence and engineering.In order to optimize its thermophysical properties at the design stage,it is of great significance to reveal the thermal response mechanism of EPMWM based on its complex structural effects.In the present work,virtual manufacturing technology(VMT)was developed to restore the physics-based 3D model of EPMWM.On this basis,the transient thermal analysis is carried out to explore the contact-relevant thermal behavior of EPMWM,and then the spiral unit containing unique structural information are further extracted and counted.In particular,the thermal resistance network is numerically constructed based on the spiral unit through the thermoelectric analogy method to accurately predict the effective thermal conductivity(ETC)of EPMWM.Finally,the thermal diffusivity and specific heat of the samples were obtained by the laser thermal analyzer to calculate the ETC and thermal insulation factor of interest.The results show that the ETC of EPMWM increases with increasing temperature or reducing density under the experimental conditions.The numerical prediction is consistent with the experimental result and the average error is less than 4%.
基金supported by the National Natural Science Foundation of China(grant number 51805086)the Natural Science Foundation of Fujian Province,China(grant number 2018J01763)。
文摘To improve the defense capability of military equipment under extreme conditions,impact-resistant and high-energy-consuming materials have to be developed.The damping characteristic of entangled porous metallic wire materials(EPMWM)for vibration isolation was previously investigated.In this paper,a study focusing on the impact-resistance of EPMWM with the consideration of ambient temperature is presented.The quasi-static and low-velocity impact mechanical behavior of EPMWM under different temperatures(25℃-300℃)are systematically studied.The results of the static compression test show that the damping energy dissipation of EPMWM increases with temperature while the nonlinear damping characteristics are gradually enhanced.During the impact experiments,the impact energy loss rate of EPMWM was between 65%and 85%,while the temperatures increased from 25℃to 300℃.Moreover,under the same drop impact conditions,the overall deformation of EPMWM decreases in the temperature range of 100℃-200℃.On the other hand,the impact stiffness,energy dissipation,and impact loss factor of EPMWM significantly increase with temperature.This can be attributed to an increase in temperature,which changes the thermal expansion coefficient and contact state of the internal wire helixes.Consequently,the energy dissipation mode(dry friction,air damping,and plastic deformation)of EPMWM is also altered.Therefore,the EPMWM may act as a potential candidate material for superior energy absorption applications.
基金supported by the National Natural Science Foundation of China(Nos.12005289 and 52071331)the National Key R&D Program of China(No.2019YFA0210000)the State Key Laboratory of Nuclear Detection and Electronics,University of Science and Technology of China(No.SKLPDE-KF-202316)。
文摘In this study,the interactions between a Ga-based liquid metal,GaInSn,and several metal materials,including pure metals(Ni and Ti)and alloys(316H stainless steel(SS)and GH3535),at 650℃were investigated.The aim was to evaluate the corrosion performance and select a suitable candidate material for use as a molten salt manometer diaphragm in thermal energy storage systems.The results indicated that the alloys(316H SS and GH3535)exhibited less corrosion than pure metals(Ni and Ti)in liquid GaInSn.Ga-rich binary intermetallic compounds were found to form on the surfaces of all the tested metal materials exposed to liquid GaInSn,as a result of the decomposition of liquid GaInSn and its reaction with the constituent elements of the metal materials.The corrosion mechanism for all the tested materials exposed to liquid GaInSn was also investigated and proposed,which may aid in selecting the optimal candidate material when liquid GaInSn is used as the pressure-sensing medium.
基金the National Key Research and Development Program of China[grant number 2018YFB1106301]Research and Development Program Project in Key Areas of Guangdong Province[grant number 2019B090907001 and 2019B010943001]+2 种基金Shenzhen Science and Technology Innovation Commission[grant number JCYJ20180504165824643]Natural Science Foundation of Guangdong Province[grant number 2020A1515011373]the National Natural Science Foundation of China[grant number 51971108].
文摘Additive manufacturing(AM), or 3D printing, is an emerging technology that “adds” materials up and constructs products through a layer-by-layer procedure. Laser powder bed fusion(LPBF) is a powder-bed-based AM technology that can fabricate a large variety of metallic materials with excellent quality and accuracy. However, various defects such as porosity,cracks, and incursions can be generated during the printing process. As the most universal and a near-inevitable defect,porosity plays a substantial role in determining the mechanical performance of as-printed products. This work presents a comprehensive review of literatures that focused on the porosity in LPBF printed metals. The formation mechanisms,evaluation methods, effects on mechanical performance with corresponding models, and controlling methods of porosity have been illustrated and discussed in-depth. Achievements in four representative metals, namely Ti-6Al-4V, 316L, Inconel 718, and Al Si10Mg, have been critically reviewed with a statistical analysis on the correlation between porosity fraction and tensile properties. Ductility has been determined as the most sensitive property to porosity among several key tensile properties. This review also provides potential directions and opportunities to address the current porosity-related challenges.
基金Sponsored by the Matching Project of Commission of Scientific and Technical Industry on National Defence(JPPT-×××-1)
文摘The precipitation of MgZn2 phase in aging process of Al-Zn-Mg-Cu alloy forging was characterized qualitatively after transmission electron microscope(TEM)observation,X-ray diffraction phase analysis and the exact measure of lattice parameter.And,the precipitation of the second-phase in aging process was simulated after test the resistivity of the alloy in a continuous heating process and delayed time processing.The results show that when heating in the same rate,the alloy resistivity increases with temperature first,a mutation point appears at 110℃,and the resistivity reaches its peak at 120℃.Then,the resistivity decreases and achieves a minimum at about 170℃.Afterwards,it increases again.The change of resistivity results from a combined effect of the temperature and phase transformation.The volume precipitation of η' phase dominates at about 120℃,and the resistivity of forgings decreases accordingly.When the specimen cools in a furnace at 240℃,the phase transformation finishes basically and the alloy content of Al-matix keeps stable,thus,the alloy resistivity depends on the temperature only.It decreases with temperature and time since the end of precipitation.The higher the temperature is,the bigger it will be.With a big descending rate of the resistivity curve,the time to reach the stable value becomes shorter.
基金supported by the National Nature Science Foundations of China(Grant No.21673263,21573265)the Independent Innovation Plan Foundations of Qingdao City of China(Grant No.16-5-1-42-jch)the western Young Scholars Foundations of Chinese Academy of Sciences
文摘Lithium-ion hybrid supercapacitors （LIHSs）, also called Li-ion capacitors, are electrochemical energy stor- age devices that combining the advantages of high power density of supercapacitor and high energy density of Li-ion battery. However, high power density and long cycle life are still challenges for the cul~ rent LIHSs due to the imbalance of charge-storage capacity and electrode kinetics between capacitor-type cathode and battery-type anode. Therefore, great efforts have been made on designing novel cathode materials with high storage capacity and anode material with enhanced kinetic behavior for LIHSs. With unique two-dimensional form and numerous appealing properties, for the past several years, the rational designed graphene and its composites materials exhibit greatly improved electrochemical performance as cathode or anode for LIHSs. Here, we summarized and discussed the latest advances of the state- of-art graphene-based materials for LIHSs applications. The major roles of graphene are highlighted as （1） a superior active material, （2） ultrathin 2D flexible support to remedy the sluggish reaction of the metal compound anode, and （3） good 2D building blocks for constructing macroscopic 3D pOFOUS car- bonjgraphene hybrids. In addition, some high performance aqueous LIHSs using graphene as electrode were also summarized. Finally, the perspectives and challenges are also proposed for further develop- ment of more advanced graphene-based LIHSs.
基金support from NTNU Nanolab and financial supports from VISTA, Zhengzhou Research Institute of Chalco and Norwegian research council
文摘Electrochemical energy storage systems with high specific energy and power as well as long cyclic stability attract increasing attention in new energy technologies. The principles for rational design of electrodes are discussed to reduce the activation, concentration, and resistance overpotentials and improve the active ma- terial efficiency in order to simultaneously achieve high specific energy and power. Three dimensional （3D） nanocomposites are currently considered as promising electrode materials due to their large surface area, reduced electronic and ionic diffusion distances, and synergistic effects. This paper reviews the most recent progress on the synthesis and application of 3D thin film nanoelectrode arrays based on aligned carbon nan- otubes （ACNTs） directly grown on metal foils for energy storages and special attentions are paid on our own representative works. These novel 3D nanoelectrode arrays on metal foil exhibit improved electrochemical performances in terms of specific energy, specific power and cyclic stability due to their unique structures. In this active materials coated ACNTs over conductive substrate structures, each component is tailored to address a different demand. The electrochemical active material is used to store energy, while the ACNTs are employed to provide a large surface area to support the active material and nanocable arrays to facilitate the electron transport. The thin film of active materials can not only reduce ion transport resistance by shorten- ing the diffusion length but also make the film elastic enough to tolerate significant volume changes during charge and discharge cycles. The conductive substrate is used as the current collector and the direct contact of the ACNT arrays with the substrate reduces significantly the contact resistance. The principles obtained from ACNT based electrodes are extended to aligned graphene based electrodes. Similar improvements have been achieved which confirms the reliability of the principles obtained. In addition, we also discuss and view the ongoing trends in development of aligned carbon nanostructures based electrodes for energy storage.
