The undesirable absorption bandwidth is the main limitation for the application of microwave absorbing materials.Noting that the design of structure and composition of absorbing coating allows it to obtain a satisfyin...The undesirable absorption bandwidth is the main limitation for the application of microwave absorbing materials.Noting that the design of structure and composition of absorbing coating allows it to obtain a satisfying absorption bandwidth and to avoid weight increasing,honeycomb and its sandwich structures coated by various absorbant have been developed and measured using an arch measurement system over2-18 GHz.To further understand the absorption mechanisms of honeycomb structural materials,simulation based on finite element method and transmission line theory is performed to analyze the different responses to the applied microwave between honeycomb structural materials and uniform-medium slab materials.The proper composition design allows control over the microwave loss mechanisms,which optimize the coating to possess both of the dielectric and magnetic advantages.For the honeycomb structural materials,the magnetic resonation is found for the first time,which is resulting from the periodic honeycomb walls on both sides of the dielectric cavity(consisting of the aramid paper interlayer and vacuum hexagonal prisms).In addition,the conversion of structure from solid to honeycomb brings about changes in impedance,propagating path,effective wavelength,effective attenuation area,microwave phases,and inductive coupling effect,etc.,which result in a better microwave absorbing performance.The honeycomb sandwich structure coated by CIP/CB/EP with the weight ratio of 4:0.03:1 shows the absorption bandwidth of~9.8 GHz for reflection loss(RL)lower than-10 dB which covers part of the S and C bands and almost the whole X and Ku bands.展开更多
The application of an external field is a promising method to control the microstructure of materials, leading to their improved performance. In the present paper, the strengthening and toughening behavior of some typ...The application of an external field is a promising method to control the microstructure of materials, leading to their improved performance. In the present paper, the strengthening and toughening behavior of some typical high-performance structural materials subjected to multifield coupling treatment, including electrostatic field, electro-pulse current, thermal field, and stress field, are reviewed in detail. In addition to the general observation that the plasticity of materials could be increased by multi-external fields, strength enhancement can be achieved by controlling atomic diffusion or phase transformations. The paper is not limited to the strengthening and toughening mechanisms of the multifield coupling effects on different types of structural materials but is intended to provide a generic method to improve both the strength and ductility of the materials. Finally, the prospects of the applications of multi-external fields have also been proposed based on current works.展开更多
Damage evolution characterization and performance evaluation under realistic conditions are essential to ensure reliable operation of critical safety components.However,previous studies focus on the surface detection ...Damage evolution characterization and performance evaluation under realistic conditions are essential to ensure reliable operation of critical safety components.However,previous studies focus on the surface detection because of very limited penetration capacity of nondestructive testing facilities.Here,we review the recent progress of material damage mechanism by various in situ testing rigs that are compat-ible with laboratory and synchrotron radiation X-ray facilities.Then,taking metallic alloys and composites as model materials,we demonstrate the unique advantages of in situ X-ray three-dimensional tomography in unveiling complex failure mechanisms,quantifying crack growth driving forces and crack closure phenomena,and elucidating the strengthening/degrading effects from microstructure and environment on structural material degradation.Finally,we also discuss the ongoing direction of in situ multi-scale visualization and characterization with the development of advanced high-energy X-ray facilities,the improvement of in situ devices and sample environments,the demand of high-throughput tests,and the processing and application of massive test data.展开更多
Activation analyses play a vital role in nuclear reactor design.Activation analyses,along with nuclear analyses,provide important information for nuclear safety and maintenance strategies.Activation analyses also help...Activation analyses play a vital role in nuclear reactor design.Activation analyses,along with nuclear analyses,provide important information for nuclear safety and maintenance strategies.Activation analyses also help in the selection of materials for a nuclear reactor,by providing the radioactivity and dose rate levels after irradiation.This information is important to help define maintenance activity for different parts of the reactor,and to plan decommissioning and radioactive waste disposal strategies.The study of activation analyses of candidate structural materials for near-term fusion reactors or ITER is equally essential,due to the presence of a highenergy neutron environment which makes decisive demands on material selection.This study comprises two parts; in the first part the activation characteristics,in a fusion radiation environment,of several elements which are widely present in structural materials,are studied.It reveals that the presence of a few specific elements in a material can diminish its feasibility for use in the nuclear environment.The second part of the study concentrates on activation analyses of candidate structural materials for near-term fusion reactors and their comparison in fusion radiation conditions.The structural materials selected for this study,i.e.India-specific Reduced Activation Ferritic-Martensitic steel（IN-RAFMS）,P91-grade steel,stainless steel 316 LN ITER-grade（SS-316 LN-IG）,stainless steel 316 L and stainless steel 304,are candidates for use in ITER either in vessel components or test blanket systems.Tungsten is also included in this study because of its use for ITER plasma-facing components.The study is carried out using the reference parameters of the ITER fusion reactor.The activation characteristics of the materials are assessed considering the irradiation at an ITER equatorial port.The presence of elements like Nb,Mo,Co and Ta in a structural material enhance the activity level as well as the dose level,which has an impact on design considerations.IN-RAFMS was shown to be a more effective low-activation material than SS-316 LN-IG.展开更多
Electrolyte electroreflectance (EER) has been widely employed to investigate the electronic energy band structure and related physical properties of semiconductors. The electrolyte electroreflectance (EER) method comb...Electrolyte electroreflectance (EER) has been widely employed to investigate the electronic energy band structure and related physical properties of semiconductors. The electrolyte electroreflectance (EER) method combined with electrochemical anodic dissolution was used to study GaAs/GaAlAs multilayer structural materials. According to variation of the EER spectra during anodic dissolution the characteristics of GaAs/GaAlAs multilayer structural materials such as properties of the interface, p-n junction positions and Al content profiles were obtained.展开更多
The use of low structural materials can accentuate the characteristics of openness advocated by regional creation.Therefore,when selecting regional game materials,preschool teachers should focus on open and low struct...The use of low structural materials can accentuate the characteristics of openness advocated by regional creation.Therefore,when selecting regional game materials,preschool teachers should focus on open and low structures as well as actively and reasonably guide the child’s game behavior,so that each child can make full and efficient use of these materials.At the same time,in a harmonious dialogue with these materials,they are given the opportunity to express what they see,hear,feel,and think in their own ways.展开更多
The existence and its movement rule of crystalline structure defect are closely related to the diffusion, solid phase reaction, sintering, phase transformation as well as the physical and chemical properties of materi...The existence and its movement rule of crystalline structure defect are closely related to the diffusion, solid phase reaction, sintering, phase transformation as well as the physical and chemical properties of materials. Point defect theory has been widely applied in material mineralization research, unfavorable transformation controlling, material modification, the research and development of new materials and so on. Point defect theory is one of the important theories for new material research and development. Herein we mainly discuss the application of point defect theory in some structural material researches.展开更多
The use of zirconia-based ceramic materials as smpport materidls for superconducting magnets and in cryopenic engineeriny generally has been considered. The relationship between compsition and mechanical properties at...The use of zirconia-based ceramic materials as smpport materidls for superconducting magnets and in cryopenic engineeriny generally has been considered. The relationship between compsition and mechanical properties at cryogenic temperature has also been investigated.展开更多
At great depth ratio, two methodologies based on the representative strain were improved to extract mechanical properties of metallic engineering structural materials from P-h curve of an indentation response. The imp...At great depth ratio, two methodologies based on the representative strain were improved to extract mechanical properties of metallic engineering structural materials from P-h curve of an indentation response. The improved aspects include： the com- bination of great ratio h1/R=0.1 and h2/R=0.4 replaced h1/R=0.01 and h2/R=0.06 （Cao＇s method） and h1/R=0.1 and h2/R=0.3 （Ogasawara＇s method）; three types of metallic engineering structural materials with obviously different elastic modulus were dealt with to get their calculation parameters, respectively; a new parameter reflecting the effect of work-hardening exponent n was introduced to get the dimensionless function which is independent of n and a relationship between W/（h3σrS） and E^＊/（σrS） at great depth ratio. By using the results of finite element simulation, the efficiency and accuracy of the improved method have been proved, and it showed that the accuracv of the improved method is much better than the former method.展开更多
Magnesium(Mg)and its alloys have been identified as one of the most promising structural,energy and biomaterials owing to their exceptional combination of properties.These include low density,high specific strength,go...Magnesium(Mg)and its alloys have been identified as one of the most promising structural,energy and biomaterials owing to their exceptional combination of properties.These include low density,high specific strength,good damping,high castability,high capacity of hydrogen storage。展开更多
Computer simulation plays a critical role in connecting microscopic structure and macroscopic mechanical properties of structural material,which is a key factor that needs to be considered in design of such kind of ma...Computer simulation plays a critical role in connecting microscopic structure and macroscopic mechanical properties of structural material,which is a key factor that needs to be considered in design of such kind of material.Via the quantum mechanics first-principles calculations,one can gain structure,elastic constant,energetics,and stress of selected material system,based on which one is able to predict the mechanical properties or provide useful insights for the mechanical properties of the materials.This can be done either directly or in combination with the empirical criterions.This paper reviews the recent research advances on the attempts to predict the mechanical properties of structural materials from first principles.展开更多
The response of three-dimensional sample of Al, containing vacancy complex, under shear loading was simulated. The molecular dynamics method was used and interaction between atoms was described on the base of pseudopo...The response of three-dimensional sample of Al, containing vacancy complex, under shear loading was simulated. The molecular dynamics method was used and interaction between atoms was described on the base of pseudopotential theory Solitary waves were generated in the sample under mechanical loading. Their interaction with the vacancy complexes was shown to be able to initiate hot spot in that local region of the complexes. Some parameters of the hot spot as well as solitary waves were calculated. The initiation of the hot spot is accompanied with sufficient local structural relaxation.展开更多
Under the synergistic effect of molecular design and devices engineering, small molecular organic solar cells have presented an unstoppable tendency for rapid development with putting forward donor- acceptor （D-A） s...Under the synergistic effect of molecular design and devices engineering, small molecular organic solar cells have presented an unstoppable tendency for rapid development with putting forward donor- acceptor （D-A） structures. Up to now, the highest power conversion efficiency of small molecules has exceeded 11%, comparable to that of polymers. In this review, we summarize the high performance small molecule donors in various classes of typical donor-acceptor （D-A） structures and discuss their relationships briefly.展开更多
TA2/TA15 graded structural material（GSM） was fabricated by the laser additive manufacturing（LAM） process. The chemical composition, microstructure and micro-hardness of the as-deposited GSM were investigated. The ...TA2/TA15 graded structural material（GSM） was fabricated by the laser additive manufacturing（LAM） process. The chemical composition, microstructure and micro-hardness of the as-deposited GSM were investigated. The results show that the TA2 part of exhibiting near-equiaxed grains was Widmanst？tten α-laths microstructure. The TA15 part containing large columnar grains was fine basket-weave microstructure. The graded zone was divided into four deposited layers with 3000 μm in thickness. As the distance from the TA2 part increases, the alloy element contents and the β phase volume fraction increase, the α phase volume fraction decreases and the microstructure shows the evolution from Widmanst？tten α-laths to basket-weave α-laths gradually. The micro-hardness increases from the TA2 part to the TA15 part due to the solid solution strengthening and grain boundary strengthening.展开更多
Energetic structural materials(ESMs)integrated a high energy density and rapid energy release with the ability to serve as structural materials.Here,a novel triple-phase TiZrHfTa_(0.7)W_(0.3)high-entropy alloy(HEA)was...Energetic structural materials(ESMs)integrated a high energy density and rapid energy release with the ability to serve as structural materials.Here,a novel triple-phase TiZrHfTa_(0.7)W_(0.3)high-entropy alloy(HEA)was fabricated and investigated as a potential ESM.A hierarchical microstructure was obtained with a main metastable body-centered-cubic(BCC)matrix with distributed Ta-W-rich BCC precipitates of various sizes and interwoven hexagonal close-packed(HCP)lamellar nano-plates.The compressive me-chanical properties were tested across a range of strain rates and demonstrated a brittle-to-ductile tran-sition as the strain rate increased while maintaining a high ultimate strength of approximately 2.5 GPa.This was due to the phase transformation from metastable matrix BCC to HCP structures.In addition,during the dynamic deformation,metal combustion originating from the failure surface was observed.Furthermore,the composition of the fragments was studied,and the results indicated that the addition of tungsten promoted combustion.Finally,the potential application of this HEA was evaluated by high-velocity penetration tests,and the results were compared to other typical structural materials for pene-trators and bullets.A comparison was conducted by assessing the geometries of the penetration channel employing two dimensionless parameters normalized by the projectile size,representing longitudinal and lateral damage,respectively.The normalized depth of the TiZrHfTa_(0.7)W_(0.3)HEA projectile was comparable to those of the other investigated materials,but the normalized diameter was the largest,showing an excellent ability to deliver lateral damage.展开更多
Owing to their exceptional properties,high-entropy alloys(HEAs)and high-entropy materials have emerged as promising research areas and shown diverse applications.Here,the recent advances in the field are comprehensive...Owing to their exceptional properties,high-entropy alloys(HEAs)and high-entropy materials have emerged as promising research areas and shown diverse applications.Here,the recent advances in the field are comprehensively reviewed,organized into five sections.The first section introduces the background of HEAs,covering their definition,significance,application prospects,basic properties,design principles,and microstructure.The subsequent section focuses on cutting-edge high-entropy structural materials,highlighting developments such as nanostructured alloys,grain boundary engineering,eutectic systems,cryogenic alloys,thin films,micro-nano-lattice structures,additive manufacturing,high entropy metallic glasses,nano-precipitate strengthened alloys,composition modulation,alloy fibers,and refractory systems.In the following section,the emphasis shifts to functional materials,exploring HEAs as catalysts,magneto-caloric materials,corrosion-resistant alloys,radiation-resistant alloys,hydrogen storage systems,and materials for biomedicine.Additionally,the review encompasses functional high-entropy materials outside the realm of alloys,including thermoelectric,quantum dots,nanooxide catalysts,energy storage materials,negative thermal expansion ceramics,and high-entropy wave absorption materials.The paper concludes with an outlook,discussing future directions and potential growth areas in the field.Through this comprehensive review,researchers,engineers,and scientists may gain valuable insights into the recent progress and opportunities for further exploration in the exciting domains of high-entropy alloys and functional materials.展开更多
A graded structural material(GSM)with a material transition from TA15 to TC11 was fabricated by wire arc additive manufacturing(WAAM)method.The grain morphology,chemical composition,microstructure and mechanical prope...A graded structural material(GSM)with a material transition from TA15 to TC11 was fabricated by wire arc additive manufacturing(WAAM)method.The grain morphology,chemical composition,microstructure and mechanical properties of the as-deposited GSM were all characterized to investigate their variations along the deposition direction.The results indicate that from TA15 to TC11,the grain size decreases and a transition from columnar grains to equiaxed grains occurs.The content of alloy element alters greatly within a short distance,and the width of the mutation zone is 800μm.Both TA15 and TC11 regions exhibit basketweave microstructure withα-phase andβ-phase.However,during the transition from TA15 to TC11,theα-lath becomes fine,which leads to an increase in microhardness.The tensile test shows that the bonding strength at the interface is higher than the longitudinal strength of TA15,and the lateral elongation at the interface is higher than that of TA15 and TC11.展开更多
Aqueous zinc ion batteries(AZIBs) demonstrate tremendous competitiveness and application prospects because of their abundant resources,low cost, high safety, and environmental friendliness. Although the advanced elect...Aqueous zinc ion batteries(AZIBs) demonstrate tremendous competitiveness and application prospects because of their abundant resources,low cost, high safety, and environmental friendliness. Although the advanced electrochemical energy storage systems based on zinc ion batteries have been greatly developed, many severe problems associated with Zn anode impede its practical application, such as the dendrite formation,hydrogen evolution, corrosion and passivation phenomenon. To address these drawbacks, electrolytes, separators, zinc alloys, interfacial modification and structural design of Zn anode have been employed at present by scientists. Among them, the structural design for zinc anode is relatively mature, which is generally believed to enhance the electroactive surface area of zinc anode, reduce local current density, and promote the uniform distribution of zinc ions on the surface of anode. In order to explore new research directions, it is crucial to systematically summarize the structural design of anode materials. Herein, this review focuses on the challenges in Zn anode, modification strategies and the three-dimensional(3D) structure design of substrate materials for Zn anode including carbon substrate materials, metal substrate materials and other substrate materials. Finally, future directions and perspectives about the Zn anode are presented for developing high-performance AZIBs.展开更多
Silicon materials have attracted wide attention as negative materials due to exceptional gravimetric capacity and abundance. The strategy of using nano-silicon materials as structural units to construct nano/micro-str...Silicon materials have attracted wide attention as negative materials due to exceptional gravimetric capacity and abundance. The strategy of using nano-silicon materials as structural units to construct nano/micro-structured silicon-based negative materials for lithium-ion batteries has come into sight in recent years. In order to provide guidance for the material structure design of micro-sized silicon-based negative materials in practical application, in this work, two commercialized nano/micro-structured silicon-based negative materials with a specific capacity of about 650 mAh·g^(-1) were investigated and compared in the aspects of material microstructure, electrochemical performance of half cells, and electrode morphological evolution during cycling. The cycling performance(with capacity retention ratio of about 17% higher after 100 cycles) and electrode structure maintenance of the embedded structure Si/C material are superior to those of core–shell Si/C material. This research can provide guidance on design and application of nano/micro-structured silicon-based negative materials.展开更多
Internal diffusion of molecules in porous materials plays an important role in many chemical processes.However,the pore diffusion capacity of porous materials cannot be measured by conventional catalyst characterizati...Internal diffusion of molecules in porous materials plays an important role in many chemical processes.However,the pore diffusion capacity of porous materials cannot be measured by conventional catalyst characterization methods.In the present paper,a pore diffusion factor,the ratio of the diffusionconstriction factor to the pore tortuosity of the porous materials,was proposed to measure the diffusion ability of pores inside solid materials,and a method was proposed for measuring the diffusion factor using a well-defined and uniform pore size material as a reference.The diffusion factor was calculated based on the effective diffusion coefficients and the diffusion-constriction factor and pore tortuosity of the reference porous materials.The pore diffusion factor measurement can be performed at room temperature and atmospheric pressure.The pore diffusion factor of conventional porous materials was found to be much smaller than 1,indicating that there is a lot of room for improving the diffusion ability of the conventional catalysts and adsorbents,and could be significantly increased through adding small number of fibers into the conventional porous materials as template.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52071053 and U1704253)the China Postdoctoral Science Foundation(No.2020M670748)+1 种基金the National Key R&D Program of China(No.2017YFB0703103)the Fundamental Research Funds for the Central Universities(No.DUT20GF111)。
文摘The undesirable absorption bandwidth is the main limitation for the application of microwave absorbing materials.Noting that the design of structure and composition of absorbing coating allows it to obtain a satisfying absorption bandwidth and to avoid weight increasing,honeycomb and its sandwich structures coated by various absorbant have been developed and measured using an arch measurement system over2-18 GHz.To further understand the absorption mechanisms of honeycomb structural materials,simulation based on finite element method and transmission line theory is performed to analyze the different responses to the applied microwave between honeycomb structural materials and uniform-medium slab materials.The proper composition design allows control over the microwave loss mechanisms,which optimize the coating to possess both of the dielectric and magnetic advantages.For the honeycomb structural materials,the magnetic resonation is found for the first time,which is resulting from the periodic honeycomb walls on both sides of the dielectric cavity(consisting of the aramid paper interlayer and vacuum hexagonal prisms).In addition,the conversion of structure from solid to honeycomb brings about changes in impedance,propagating path,effective wavelength,effective attenuation area,microwave phases,and inductive coupling effect,etc.,which result in a better microwave absorbing performance.The honeycomb sandwich structure coated by CIP/CB/EP with the weight ratio of 4:0.03:1 shows the absorption bandwidth of~9.8 GHz for reflection loss(RL)lower than-10 dB which covers part of the S and C bands and almost the whole X and Ku bands.
基金financially supported by the National Natural Science Foundation of China (Nos. U1708253 and 51571052)the Major Technology Projects of Liaoning Province, China (No. 2019JH1/10100004)the Natural Science Foundation of Liaoning Province, China (No. 2019MS-122)。
文摘The application of an external field is a promising method to control the microstructure of materials, leading to their improved performance. In the present paper, the strengthening and toughening behavior of some typical high-performance structural materials subjected to multifield coupling treatment, including electrostatic field, electro-pulse current, thermal field, and stress field, are reviewed in detail. In addition to the general observation that the plasticity of materials could be increased by multi-external fields, strength enhancement can be achieved by controlling atomic diffusion or phase transformations. The paper is not limited to the strengthening and toughening mechanisms of the multifield coupling effects on different types of structural materials but is intended to provide a generic method to improve both the strength and ductility of the materials. Finally, the prospects of the applications of multi-external fields have also been proposed based on current works.
基金supported by the National Natural Science Foundation of China(Nos.U2032121,12192212,and 52325407).
文摘Damage evolution characterization and performance evaluation under realistic conditions are essential to ensure reliable operation of critical safety components.However,previous studies focus on the surface detection because of very limited penetration capacity of nondestructive testing facilities.Here,we review the recent progress of material damage mechanism by various in situ testing rigs that are compat-ible with laboratory and synchrotron radiation X-ray facilities.Then,taking metallic alloys and composites as model materials,we demonstrate the unique advantages of in situ X-ray three-dimensional tomography in unveiling complex failure mechanisms,quantifying crack growth driving forces and crack closure phenomena,and elucidating the strengthening/degrading effects from microstructure and environment on structural material degradation.Finally,we also discuss the ongoing direction of in situ multi-scale visualization and characterization with the development of advanced high-energy X-ray facilities,the improvement of in situ devices and sample environments,the demand of high-throughput tests,and the processing and application of massive test data.
文摘Activation analyses play a vital role in nuclear reactor design.Activation analyses,along with nuclear analyses,provide important information for nuclear safety and maintenance strategies.Activation analyses also help in the selection of materials for a nuclear reactor,by providing the radioactivity and dose rate levels after irradiation.This information is important to help define maintenance activity for different parts of the reactor,and to plan decommissioning and radioactive waste disposal strategies.The study of activation analyses of candidate structural materials for near-term fusion reactors or ITER is equally essential,due to the presence of a highenergy neutron environment which makes decisive demands on material selection.This study comprises two parts; in the first part the activation characteristics,in a fusion radiation environment,of several elements which are widely present in structural materials,are studied.It reveals that the presence of a few specific elements in a material can diminish its feasibility for use in the nuclear environment.The second part of the study concentrates on activation analyses of candidate structural materials for near-term fusion reactors and their comparison in fusion radiation conditions.The structural materials selected for this study,i.e.India-specific Reduced Activation Ferritic-Martensitic steel（IN-RAFMS）,P91-grade steel,stainless steel 316 LN ITER-grade（SS-316 LN-IG）,stainless steel 316 L and stainless steel 304,are candidates for use in ITER either in vessel components or test blanket systems.Tungsten is also included in this study because of its use for ITER plasma-facing components.The study is carried out using the reference parameters of the ITER fusion reactor.The activation characteristics of the materials are assessed considering the irradiation at an ITER equatorial port.The presence of elements like Nb,Mo,Co and Ta in a structural material enhance the activity level as well as the dose level,which has an impact on design considerations.IN-RAFMS was shown to be a more effective low-activation material than SS-316 LN-IG.
文摘Electrolyte electroreflectance (EER) has been widely employed to investigate the electronic energy band structure and related physical properties of semiconductors. The electrolyte electroreflectance (EER) method combined with electrochemical anodic dissolution was used to study GaAs/GaAlAs multilayer structural materials. According to variation of the EER spectra during anodic dissolution the characteristics of GaAs/GaAlAs multilayer structural materials such as properties of the interface, p-n junction positions and Al content profiles were obtained.
文摘The use of low structural materials can accentuate the characteristics of openness advocated by regional creation.Therefore,when selecting regional game materials,preschool teachers should focus on open and low structures as well as actively and reasonably guide the child’s game behavior,so that each child can make full and efficient use of these materials.At the same time,in a harmonious dialogue with these materials,they are given the opportunity to express what they see,hear,feel,and think in their own ways.
基金This work was supported by the "863" program (No. 2003AA322020)
文摘The existence and its movement rule of crystalline structure defect are closely related to the diffusion, solid phase reaction, sintering, phase transformation as well as the physical and chemical properties of materials. Point defect theory has been widely applied in material mineralization research, unfavorable transformation controlling, material modification, the research and development of new materials and so on. Point defect theory is one of the important theories for new material research and development. Herein we mainly discuss the application of point defect theory in some structural material researches.
文摘The use of zirconia-based ceramic materials as smpport materidls for superconducting magnets and in cryopenic engineeriny generally has been considered. The relationship between compsition and mechanical properties at cryogenic temperature has also been investigated.
文摘At great depth ratio, two methodologies based on the representative strain were improved to extract mechanical properties of metallic engineering structural materials from P-h curve of an indentation response. The improved aspects include： the com- bination of great ratio h1/R=0.1 and h2/R=0.4 replaced h1/R=0.01 and h2/R=0.06 （Cao＇s method） and h1/R=0.1 and h2/R=0.3 （Ogasawara＇s method）; three types of metallic engineering structural materials with obviously different elastic modulus were dealt with to get their calculation parameters, respectively; a new parameter reflecting the effect of work-hardening exponent n was introduced to get the dimensionless function which is independent of n and a relationship between W/（h3σrS） and E^＊/（σrS） at great depth ratio. By using the results of finite element simulation, the efficiency and accuracy of the improved method have been proved, and it showed that the accuracv of the improved method is much better than the former method.
文摘Magnesium(Mg)and its alloys have been identified as one of the most promising structural,energy and biomaterials owing to their exceptional combination of properties.These include low density,high specific strength,good damping,high castability,high capacity of hydrogen storage。
基金supported by the National Natural Science Foundation of China (Grant No. 51061130558)
文摘Computer simulation plays a critical role in connecting microscopic structure and macroscopic mechanical properties of structural material,which is a key factor that needs to be considered in design of such kind of material.Via the quantum mechanics first-principles calculations,one can gain structure,elastic constant,energetics,and stress of selected material system,based on which one is able to predict the mechanical properties or provide useful insights for the mechanical properties of the materials.This can be done either directly or in combination with the empirical criterions.This paper reviews the recent research advances on the attempts to predict the mechanical properties of structural materials from first principles.
文摘The response of three-dimensional sample of Al, containing vacancy complex, under shear loading was simulated. The molecular dynamics method was used and interaction between atoms was described on the base of pseudopotential theory Solitary waves were generated in the sample under mechanical loading. Their interaction with the vacancy complexes was shown to be able to initiate hot spot in that local region of the complexes. Some parameters of the hot spot as well as solitary waves were calculated. The initiation of the hot spot is accompanied with sufficient local structural relaxation.
基金supported by the National Natural Science Foundation of China (Nos. 21474022, 51603051)Youth Innovation Promotion Association CAS and Beijing Nova Program (No. Z171100001117062)the Chinese Academy of Sciences
文摘Under the synergistic effect of molecular design and devices engineering, small molecular organic solar cells have presented an unstoppable tendency for rapid development with putting forward donor- acceptor （D-A） structures. Up to now, the highest power conversion efficiency of small molecules has exceeded 11%, comparable to that of polymers. In this review, we summarize the high performance small molecule donors in various classes of typical donor-acceptor （D-A） structures and discuss their relationships briefly.
基金Project(2010CB731705)supported by the National Basic Research Program of China
文摘TA2/TA15 graded structural material（GSM） was fabricated by the laser additive manufacturing（LAM） process. The chemical composition, microstructure and micro-hardness of the as-deposited GSM were investigated. The results show that the TA2 part of exhibiting near-equiaxed grains was Widmanst？tten α-laths microstructure. The TA15 part containing large columnar grains was fine basket-weave microstructure. The graded zone was divided into four deposited layers with 3000 μm in thickness. As the distance from the TA2 part increases, the alloy element contents and the β phase volume fraction increase, the α phase volume fraction decreases and the microstructure shows the evolution from Widmanst？tten α-laths to basket-weave α-laths gradually. The micro-hardness increases from the TA2 part to the TA15 part due to the solid solution strengthening and grain boundary strengthening.
基金supported by the National Natu-ral Science Foundation of China(Nos.51401028,51271193 and 11790292)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB22040303)the Innovation Pro-gram(No.237099000000170004).
文摘Energetic structural materials(ESMs)integrated a high energy density and rapid energy release with the ability to serve as structural materials.Here,a novel triple-phase TiZrHfTa_(0.7)W_(0.3)high-entropy alloy(HEA)was fabricated and investigated as a potential ESM.A hierarchical microstructure was obtained with a main metastable body-centered-cubic(BCC)matrix with distributed Ta-W-rich BCC precipitates of various sizes and interwoven hexagonal close-packed(HCP)lamellar nano-plates.The compressive me-chanical properties were tested across a range of strain rates and demonstrated a brittle-to-ductile tran-sition as the strain rate increased while maintaining a high ultimate strength of approximately 2.5 GPa.This was due to the phase transformation from metastable matrix BCC to HCP structures.In addition,during the dynamic deformation,metal combustion originating from the failure surface was observed.Furthermore,the composition of the fragments was studied,and the results indicated that the addition of tungsten promoted combustion.Finally,the potential application of this HEA was evaluated by high-velocity penetration tests,and the results were compared to other typical structural materials for pene-trators and bullets.A comparison was conducted by assessing the geometries of the penetration channel employing two dimensionless parameters normalized by the projectile size,representing longitudinal and lateral damage,respectively.The normalized depth of the TiZrHfTa_(0.7)W_(0.3)HEA projectile was comparable to those of the other investigated materials,but the normalized diameter was the largest,showing an excellent ability to deliver lateral damage.
基金financially supported by the National Key R&D Program of China(No.2021YFB3802800)the National Natural Science Foundation of China(Nos.52222104,12261160364,51871120,51520105001,22275089,52071157,52231005,52201174,52171165,52261033,52371155,51801128,52171219,U20A20278,52371106,22071221,52122408,52201190,22075014,52272040,62222405,22125602,and 52301052)+11 种基金the Natural Science Foundation of Jiangsu Province(Nos.BK20200019,BK20220858 and BK20231458)support by the open research fund of Songshan Lake Materials Laboratory(No.2022SLABFN19)support by Guangdong Basic and Applied Basic Research Foundation(No2024B1515020010)support by Shanxi Province Youth Innovation Team Project(No.22JP042)support by the National Science Fund for Distinguished Young Scholars of China(No.52325102)support by the Large Scientific Facility Open Subject of Songshan Lake,Dongguan,Guangdongsupport by the research institute for Advanced Manufacturing Fund(No.P0046108)support by the Hong Kong RGC general research fund(No.11200623)and CRF project C7074-23Gfinancial support from the Australian Research CouncilHBIS-UQ Innovation Centre for Sustainable Steel projectthe QUT Capacity Building Professor Programsupport by the Fundamental Research Funds for the Central Universities(No.30923010211)。
文摘Owing to their exceptional properties,high-entropy alloys(HEAs)and high-entropy materials have emerged as promising research areas and shown diverse applications.Here,the recent advances in the field are comprehensively reviewed,organized into five sections.The first section introduces the background of HEAs,covering their definition,significance,application prospects,basic properties,design principles,and microstructure.The subsequent section focuses on cutting-edge high-entropy structural materials,highlighting developments such as nanostructured alloys,grain boundary engineering,eutectic systems,cryogenic alloys,thin films,micro-nano-lattice structures,additive manufacturing,high entropy metallic glasses,nano-precipitate strengthened alloys,composition modulation,alloy fibers,and refractory systems.In the following section,the emphasis shifts to functional materials,exploring HEAs as catalysts,magneto-caloric materials,corrosion-resistant alloys,radiation-resistant alloys,hydrogen storage systems,and materials for biomedicine.Additionally,the review encompasses functional high-entropy materials outside the realm of alloys,including thermoelectric,quantum dots,nanooxide catalysts,energy storage materials,negative thermal expansion ceramics,and high-entropy wave absorption materials.The paper concludes with an outlook,discussing future directions and potential growth areas in the field.Through this comprehensive review,researchers,engineers,and scientists may gain valuable insights into the recent progress and opportunities for further exploration in the exciting domains of high-entropy alloys and functional materials.
基金financial supports from the National Natural Science Foundation of China(Nos.51875041,51875042)。
文摘A graded structural material(GSM)with a material transition from TA15 to TC11 was fabricated by wire arc additive manufacturing(WAAM)method.The grain morphology,chemical composition,microstructure and mechanical properties of the as-deposited GSM were all characterized to investigate their variations along the deposition direction.The results indicate that from TA15 to TC11,the grain size decreases and a transition from columnar grains to equiaxed grains occurs.The content of alloy element alters greatly within a short distance,and the width of the mutation zone is 800μm.Both TA15 and TC11 regions exhibit basketweave microstructure withα-phase andβ-phase.However,during the transition from TA15 to TC11,theα-lath becomes fine,which leads to an increase in microhardness.The tensile test shows that the bonding strength at the interface is higher than the longitudinal strength of TA15,and the lateral elongation at the interface is higher than that of TA15 and TC11.
基金financially supported by the National Natural Science Foundation of China (Grants Nos. 52064013, 52064014, 52072323 and 52122211)the “Double-First Class” Foundation of Materials and Intelligent Manufacturing Discipline of Xiamen University。
文摘Aqueous zinc ion batteries(AZIBs) demonstrate tremendous competitiveness and application prospects because of their abundant resources,low cost, high safety, and environmental friendliness. Although the advanced electrochemical energy storage systems based on zinc ion batteries have been greatly developed, many severe problems associated with Zn anode impede its practical application, such as the dendrite formation,hydrogen evolution, corrosion and passivation phenomenon. To address these drawbacks, electrolytes, separators, zinc alloys, interfacial modification and structural design of Zn anode have been employed at present by scientists. Among them, the structural design for zinc anode is relatively mature, which is generally believed to enhance the electroactive surface area of zinc anode, reduce local current density, and promote the uniform distribution of zinc ions on the surface of anode. In order to explore new research directions, it is crucial to systematically summarize the structural design of anode materials. Herein, this review focuses on the challenges in Zn anode, modification strategies and the three-dimensional(3D) structure design of substrate materials for Zn anode including carbon substrate materials, metal substrate materials and other substrate materials. Finally, future directions and perspectives about the Zn anode are presented for developing high-performance AZIBs.
基金financially supported by the National Key R&D Program of China(No.2016YFB0100400)the National Natural Science Foundation of China(Nos.51504032,51604032 and U1664256)。
文摘Silicon materials have attracted wide attention as negative materials due to exceptional gravimetric capacity and abundance. The strategy of using nano-silicon materials as structural units to construct nano/micro-structured silicon-based negative materials for lithium-ion batteries has come into sight in recent years. In order to provide guidance for the material structure design of micro-sized silicon-based negative materials in practical application, in this work, two commercialized nano/micro-structured silicon-based negative materials with a specific capacity of about 650 mAh·g^(-1) were investigated and compared in the aspects of material microstructure, electrochemical performance of half cells, and electrode morphological evolution during cycling. The cycling performance(with capacity retention ratio of about 17% higher after 100 cycles) and electrode structure maintenance of the embedded structure Si/C material are superior to those of core–shell Si/C material. This research can provide guidance on design and application of nano/micro-structured silicon-based negative materials.
基金supported by the National Nature Science Foundation of China(Grant No:91534120)。
文摘Internal diffusion of molecules in porous materials plays an important role in many chemical processes.However,the pore diffusion capacity of porous materials cannot be measured by conventional catalyst characterization methods.In the present paper,a pore diffusion factor,the ratio of the diffusionconstriction factor to the pore tortuosity of the porous materials,was proposed to measure the diffusion ability of pores inside solid materials,and a method was proposed for measuring the diffusion factor using a well-defined and uniform pore size material as a reference.The diffusion factor was calculated based on the effective diffusion coefficients and the diffusion-constriction factor and pore tortuosity of the reference porous materials.The pore diffusion factor measurement can be performed at room temperature and atmospheric pressure.The pore diffusion factor of conventional porous materials was found to be much smaller than 1,indicating that there is a lot of room for improving the diffusion ability of the conventional catalysts and adsorbents,and could be significantly increased through adding small number of fibers into the conventional porous materials as template.
