1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain bounda...1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain boundaries(GBs),which restricts local plastic flow dur-ing the plastic deformation and leads to stress concentration[3,4].Recently,the development of concepts aimed at achieving hetero-geneous grain has emerged as a promising approach for enhanc-ing comprehensive mechanical properties[5,6].展开更多
The rapid expansion of marine industries has created an urgent demand for advanced engineering materials with superior multifunctional performance.While Cu-Ni alloys demonstrate favorable stability and tribological ch...The rapid expansion of marine industries has created an urgent demand for advanced engineering materials with superior multifunctional performance.While Cu-Ni alloys demonstrate favorable stability and tribological characteristics,their practical applications are constrained by compromised thermal conductivity and insufficient mechanical strength due to the solid solution of a high amount of Ni in the Cu matrix.Cu-Ni matrix composites reinforced with hexagonal boron nitride(h-BN)have garnered significant attention due to their potential for tailored mechanical and thermal properties.However,challenges such as BN agglomerations in Cu-Ni matrix and poor interfacial bonding hinder their practical applications.To address these limitations,this study proposes an innovative fabrication strategy for boron nitride nanosheets(BNNSs)reinforced Cu-Ni composites by integrating the in situ synthesis of BNNSs on Cu powders via chemical vapor deposition with powder metallurgy.Benefited by the in situ strategy,BNNSs with high crystallinity distribute uniformly within the Cu matrix and have an intimate interfacial bonding without voids or other types of defects.Remarkably,the BNNSs/Cu-30%Ni composite achieves simultaneous enhancement in strength and ductility,exhibiting an ultimate tensile strength of 417 MPa and fracture elongation of 17.5%,representing 30%and 118%improvements over pure Cu-Ni alloys,respectively.This exceptional mechanical synergy originates from threefold strengthening mechanisms:grain refinement,mobile dislocation pinning,and efficient stress transfer via robust interfaces.The microstructural analysis confirms that homogenous distribution of BNNSs optimized stress distribution,mitigating strain localization in the composites.Fractographic examination demonstrates uniformly distributed dimples containing embedded BNNSs,indicative of effective crack bridging and deflection during failure.Furthermore,the composite possesses excellent corrosion resistance comparable to matrix alloys,while achieving 21.23%enhancement in thermal conductivity and 20%reduction in coefficient of friction.The scalable fabrication protocol successfully resolves longstanding challenges in BNNSs dispersion and interfacial bonding,offering a viable pathway for designing high-performance CMCs for marine applications.展开更多
The composites prepared by combining lightweight carbon materials with magnetic metals have demonstrated excellent dielectric and magnetic properties,indicating potential applications in the field of electromagnetic w...The composites prepared by combining lightweight carbon materials with magnetic metals have demonstrated excellent dielectric and magnetic properties,indicating potential applications in the field of electromagnetic wave(EMW)absorption.However,the rational microstructure design and component optimization of these composites in regulating their magnetic-dielectric balance to achieve high-performance EMW absorption remains challenging.Herein,hierarchical yolk-shell Fe@SiO_(2)@NC composites with dual impedance matching layers and dual built-in electric fields were prepared by self-template aggregation and in situ reduction strategies.The introduction of a SiO_(2)wave-transparent layer into a conventional dielectric-magnetic system has resulted in the successful realization of nanoscale precise impedance matching regulation in absorbers,thereby enabling effective ultra-wideband EMW absorption.The dual impedance matching layers of the internal void layer and the SiO_(2)wave-transparent layer facilitate multiple scattering and reflection of EMWs within the absorbers,and the dual built-in electric fields of Fe/SiO_(2)and SiO_(2)/NC can effectively enhance interfacial polarization effect to attenuate EMWs.The predominantly optimized Fe@SiO_(2)@NC-2 exhibits an ultra-wide effective absorption bandwidth(EAB)of 7.10 GHz and an impressive minimum reflection loss(RL_(min))of−64.83 dB,indicating that optimizing the impedance matching via quantitative design can maximize the EMW absorption performance.This work provides a straightforward yet effective approach for constructing multi-component materials with hierarchical yolk-shell structure,which offers valuable insight into the microstructure design and component optimization of innovative EMW absorption materials.展开更多
To synthesize graphene economically and efficiently,as well as to improve the interface bonding between graphene and metal and to recede the aggregation issue of graphene,in this work,an easy and scalable bottom-up st...To synthesize graphene economically and efficiently,as well as to improve the interface bonding between graphene and metal and to recede the aggregation issue of graphene,in this work,an easy and scalable bottom-up strategy for the mass production of metal nanoparticles modified graphene nanoplates(GNPs)was proposed.Cu nanoparticles modified GNPs(Cu-GNPs)and Ni nanoparticles modified GNPs(Ni-GNPs)were fabricated through this method,and then compounded with Al via ball milling technique.The asobtained Ni-GNPs/Al composite showed simultaneously improved strength and toughness compared with unreinforced Al,while the Cu-GNPs/Al composite presented a greater strengthening effect.The microstructure and interface of the two composites were carefully characterized and investigated to reveal the difference.First principle study was also adopted to explore the binding energy of different interface structures.This study could provide new insights into the fabrication of GNPs and the control of interface in GNPs/Al composites.展开更多
Three types of carbon nano-onions（CNOs） including Ni@CNOs.Fe3C@CNOs and Fe0.64Ni0.36@CNOs nanoparticles have been synthesized by catalytic decomposition of methane at 850 ℃ using nickel,iron and iron-nickel alloy c...Three types of carbon nano-onions（CNOs） including Ni@CNOs.Fe3C@CNOs and Fe0.64Ni0.36@CNOs nanoparticles have been synthesized by catalytic decomposition of methane at 850 ℃ using nickel,iron and iron-nickel alloy catalysts.Comparative and systematic studies have been carried out on the morphology,structural characteristics and graphitic crystallinity of these CNOs products.Furthermore,the electrochemical hydrogen storage properties of three types of CNOs have been investigated.Measurements show that the Ni@CNOs have the highest discharge capacity of 387.2 mAh/g,coiTesponding to a hydrogen storage of 1.42%.This comparison study shows the advantages of each catalyst in the growth of CNOs.enabling the controllable synthesis and tuning the properties of CNOs by mediating different metals and their alloy for using in the fuel cell system.展开更多
The deformation incompatibility of components is a bottleneck restricting the exaltation of the strength and ductility of composites.Herein,the coherent transition interface was designed and produced in hexagonal boro...The deformation incompatibility of components is a bottleneck restricting the exaltation of the strength and ductility of composites.Herein,the coherent transition interface was designed and produced in hexagonal boron nitride nanosheets(BNNSs)/Al composites by reaction sintering route,expecting to re-lieve the deformation incompatibility between BNNSs and Al.It is demonstrated that with the sintering temperature for composites raising from 600℃ to 650℃,700℃ and 750℃,different interface bonding characteristics,which involve nucleation and growth of AlN continuous nanolayer,were confirmed.Fur-thermore,first-principles calculations show that the generation of the coherent transition interface im-proved the interfacial bonding strength of BNNSs/Al composites through covalent bonds.The composites with coherent transition interface exhibit excellent strength-toughness combination in tensile and impact tests.The finite element simulation and in-situ approach under tensile tests were applied to investigate the influence of transition interface structure on deformation behavior of BNNSs/Al composite.It is found that the generation of the transition interface can not only weaken the stress partitioning behavior in the elastic stage,but also constrain the crack initiation and propagation behavior in the elastic-plastic stage and plastic stage,thereby improving the deformation compatibility between BNNSs and Al.The present work provides a novel view into the breakthrough for the trade-offrelationship of strength and ductility by coherent transition interface design in nanocomposites.展开更多
In order to improve the interface wettability as well as the interfacial bonding between graphene and copper matrix,in this work,graphene nanoplates modified with nickel nanoparticles(Ni-GNPs)were synthesized using a ...In order to improve the interface wettability as well as the interfacial bonding between graphene and copper matrix,in this work,graphene nanoplates modified with nickel nanoparticles(Ni-GNPs)were synthesized using a one-step method based on spray-drying and chemical vapor deposition.Thereafter,0.33 wt%Ni-GNPs were introduced into copper matrix composite by the molecular-level mixing method,leading to further enhancement of 90%in yield strength.This is attributed to the presence of Ni-GNPs,which provided high resistance to matrix against deformation.In addition,with the modification of nickel at the interface,the wettability and interfacial bonding between graphene nanoplates and copper matrix were improved,which enhanced the load transfer then.Furthermore,the microstructures and strengthening mechanisms were investigated and discus sed meanwhile.展开更多
The integrity and regularity of pore morphology play an important role in determining the mechanical properties of the metallic foam materials.The conventional methods on refining pore morphology are mainly focused on...The integrity and regularity of pore morphology play an important role in determining the mechanical properties of the metallic foam materials.The conventional methods on refining pore morphology are mainly focused on the optimization of fabrication techniques,however,they are usually inconvenient and complicated.Recently,incorporating nano reinforcement is considered to be a suitable way to fabricate metallic composite foams accompanied by optimized pore morphology and enhanced mechanical properties.In this work,through a facile and rapid powder metallurgy foaming method,the aluminum-silicon(Al-Si)alloy composite foams reinforced by graphene nanosheets(GNSs)are successfully fabricated.The microstructure analyses reveal that,for the Al-Si alloy foams incorporating the GNSs(GNSs/Al-Si composite foams),the pore size is transformed to be smaller,the pore size distributions become more homogeneous and the pore shape is also refined to a regular and roundish state.Meanwhile,the shape of Si precipitates is found transforming from an irregular long strip(length of~20μm,width of~5μm)to a fine particle state(diameter of~5μm).Moreover,the compressive testing results show that,the 0.4wt%GNSs/Al-Si composite foams own the optimal compression stress of 11.7±0.5 MPa,plateau stress of 10.0±1.0 MPa and energy absorption capacity of 6.8±0.7 MJ/m^(3),which have improvement of 58.1%,53.8%and 51.1%in comparison with the Al-Si alloy foams counterpart,respectively.The present findings may pave a new way for developing new generation of metallic composite foams that with stable microstructure and excellent mechanical performance.展开更多
In this study,Cu nanoparticles-coated graphene nanoplatelets(Cu-NPs@GNPs)were synthesized by a simple in situ method with the assistance of Na Cl templates and used for reinforcing Al–10 Si composites through stir ca...In this study,Cu nanoparticles-coated graphene nanoplatelets(Cu-NPs@GNPs)were synthesized by a simple in situ method with the assistance of Na Cl templates and used for reinforcing Al–10 Si composites through stir casting process.The experimental results showed that the coating of Cu-NPs on the GNPs could compromise the density mismatch between GNPs and metal matrix and eff ectively hinder the float of GNPs during stirring.The reaction of Cu-NPs and Al matrix could protect the structural integrity of GNPs as well as improve the interfacial wettability between GNPs and the matrix,thus promoting the uniform dispersion of GNPs in the composites.As a result,the as-prepared 0.5 wt%Cu-NPs@GNPs/Al–10 Si composite exhibited a tensile strength of 251 MPa(45%higher than the Al–10 Si)with a total elongation of 15%.The strengthening eff ects were mainly attributed to the following three reasons:Firstly,the Cu-NPs coating improved the interfacial bonding between GNPs and Al matrix which promoted the load transfer from the matrix to the GNPs.Secondly,the nanoscale Al 2 Cu formed by the reaction of Cu-NPs and Al matrix played a role in precipitation strengthening.Thirdly,GNPs refined the silicon phases and improved the monolithic performances of the composites.展开更多
Microstructural and mechanical behavior of heat treatable Al-4.6Cu binary alloy reinforced with graphene nanoplates(GNPs) in different heat treatment status were investigated in this paper.The addition of GNPs signifi...Microstructural and mechanical behavior of heat treatable Al-4.6Cu binary alloy reinforced with graphene nanoplates(GNPs) in different heat treatment status were investigated in this paper.The addition of GNPs significantly enhanced the yield strength and tensile strength of Al-Cu alloy regardless of the heattreatment conditions.It was also found that GNPs accelerated the formation of precipitates,leading to a greatly shortened aging time for GNPs/Al-4.6Cu composite to reach the peak hardness.However,aging treatment enhanced the strength of GNPs/Al-Cu composite very little,which could be explained by the interaction between GNPs,precipitates and dislocations.This work inspires us that the heat treatment process of aluminum alloy matrix composites should be designed independently with the matrix in quest of an optimum performance.展开更多
Huangqin tea(HQT),derived from the aerial parts of various Scutellaria species,in particular S.baicalensis Georgi,has a long history of traditional use in China.Its significance has grown in recent years due to its po...Huangqin tea(HQT),derived from the aerial parts of various Scutellaria species,in particular S.baicalensis Georgi,has a long history of traditional use in China.Its significance has grown in recent years due to its potential anti-aging,colon cancer chemopreventive,and cardiovascular protective properties.Huangqin tea source plants have identified over 295 chemical constituents,including flavonoids,essential oils,phenolic acids,sterols,diterpenes,polysaccharides,and amino acids.Pharmacological research has underscored the diverse beneficial effects of Huangqin tea and flavonoid extracts.These effects encompass anti-inflammatory,antiviral,anti-bacterial,antipyretic,and analgesic properties,along with neuroprotective effects and protection against cardiovascular and cerebrovascular diseases.Safety studies indicate that HQT is generally safe within recommended dosages and historical use.HQT presents multifaceted potential health benefits,though comprehensive research is necessary to ensure its effectiveness and safety in human applications.展开更多
The Sabatier principle has been widely used for designing electrocatalysts for energy conversion applications,but it is rarely mentioned in the research of cathode catalyst of Li-CO_(2) batteries.In our work,the"...The Sabatier principle has been widely used for designing electrocatalysts for energy conversion applications,but it is rarely mentioned in the research of cathode catalyst of Li-CO_(2) batteries.In our work,the"volcanic"relationship between the catalytic activity and the adsorption energy of the catalyst to the intermediates is first demonstrated based on the first-principles calculation,which meets the Sabatier principle and can be used to design the cathode catalysts.The increases in the number of nitrogenvacancy in WN shift the d-band center and increase the interaction with the reactants.The catalytic activity increases first and then decreases with the increase of adsorption energy,which was proved in the experiment.The optimal catalyst for moderate adsorption of intermediate makes the thin LiaCO_(3) distribute evenly.It exhibits a median voltage difference of 0.68 V and an energy efficiency of 84.33%at20μA cm^(-2)with a limited capacity of 200μA h cm^(-2).展开更多
The structural deterioration caused by the relatively weak out-of-plane bending stiffness and the chemically-active edge area of graphene limits its outperformance in strengthening for Al matrix composites(AMCs).Intro...The structural deterioration caused by the relatively weak out-of-plane bending stiffness and the chemically-active edge area of graphene limits its outperformance in strengthening for Al matrix composites(AMCs).Introducing one-dimensional(1D)carbon nanotubes(CNTs)to graphene/metal system is one of the promised strategies to complement the weakness of 2D graphene and make full use of the outstanding intrinsic properties of the both reinforcements.To date,such synergistic strengthening and toughening mechanisms are largely unknown.In this study,AMCs reinforced by a novel hybrid reinforcement,i.e.,graphene nanosheets decorated with Cu nanoparticles and CNTs(Cu@GNS-CNTs),are fabricated by an in-situ synthesis method.The combined contrast experiments validated that the organically integrated reinforcing structure promotes the intrinsic load bearing capacity of GNS and the strain hardening capability of the Al matrix simultaneously.As a result,the composites achieved excellent tensile strength and uniform elongation with almost no loss.The strengthening mechanism originated primarily from the hybrid reinforcement exhibits superior load-transfer,fracture inhibition and dislocation storage capability by controlling the interface reaction to construct an effective interface structure without damaging the reinforcement.Our work identifies a promising structural modification strategy for 2D materials and provides mechanistic insights into the synergistic strengthening effect of graphene/CNTs hybrid reinforcement.展开更多
1.Introduction To mitigate the distressing problem of mutual exclusion between mechanical properties-electrical conductivity(EC)in Cu alloy and meet the multiple requirements on properties,suitable ad-ditive phases wi...1.Introduction To mitigate the distressing problem of mutual exclusion between mechanical properties-electrical conductivity(EC)in Cu alloy and meet the multiple requirements on properties,suitable ad-ditive phases with combined extraordinary performance have commonly been utilized to endow Cu matrix composites with comprehensive properties[1-4].Promoting dislocation-phase boundary interactions and interfacial bonding enables markedly altering the strength of composites through phase boundary strengthening and loading transfer.展开更多
The construction and application of traditional high-strength 7075 aluminum alloy(Al7075) through selective laser melting(SLM) are currently restricted by the serious hot cracking phenomenon. To address this critical ...The construction and application of traditional high-strength 7075 aluminum alloy(Al7075) through selective laser melting(SLM) are currently restricted by the serious hot cracking phenomenon. To address this critical issue, in this study, Si is employed to assist the SLM printing of high-strength Al7075. The laser energy density during SLM is optimized, and the eff ects of Si element on solidification path, relative density, microstructure and mechanical properties of Al7075 alloy are studied systematically. With the modified solidification path, laser energy density, and the dense microstructure with refined grain size and semi-continuous precipitates network at grain boundaries, which consists of fine Si, β-MgSi, Q-phase and θ-AlCu, the hot cracking phenomenon and mechanical properties are eff ectively improved. As a result, the tensile strength of the SLM-processed Si-modified Al7075 can reach 486 ± 3 MPa, with a high relative density of ~ 99.4%, a yield strength of 291 ± 8 MPa, fracture elongation of(6.4 ± 0.4)% and hardness of 162 ± 2(HV) at the laser energy density of 112.5 J/mm~3. The main strengthening mechanism with Si modification is demonstrated to be the synergetic enhancement of grain refinement, solution strengthening, load transfer, and dislocation strengthening. This work will inspire more new design of high-strength alloys through SLM.展开更多
The development of sodium-ion(SIBs)and potassium-ion batteries(PIBs)has increased rapidly because of the abundant resources and cost-effectiveness of Na and K.Antimony(Sb)plays an important role in SIBs and PIBs becau...The development of sodium-ion(SIBs)and potassium-ion batteries(PIBs)has increased rapidly because of the abundant resources and cost-effectiveness of Na and K.Antimony(Sb)plays an important role in SIBs and PIBs because of its high theoretical capacity,proper working voltage,and low cost.However,Sb-based anodes have the drawbacks of large volume changes and weak charge transfer during the charge and discharge processes,thus leading to poor cycling and rapid capacity decay.To address such drawbacks,many strategies and a variety of Sb-based materials have been developed in recent years.This review systematically introduces the recent research progress of a variety of Sb-based anodes for SIBs and PIBs from the perspective of composition selection,preparation technologies,structural characteristics,and energy storage behaviors.Moreover,corresponding examples are presented to illustrate the advantages or disadvantages of these anodes.Finally,we summarize the challenges of the development of Sb-based materials for Na/K-ion batteries and propose potential research directions for their further development.展开更多
1.Introduction Driven by the engineering application of transportation and aerospace,simultaneously achieving excellent mechanical properties and corrosion resistance are urgently required for the next-generation Al m...1.Introduction Driven by the engineering application of transportation and aerospace,simultaneously achieving excellent mechanical properties and corrosion resistance are urgently required for the next-generation Al matrix composites(AMCs)[1,2].展开更多
Nanoscale segregation of alien solute atoms at the grain boundary(GB)can enhance the stability and mechanical properties of the GB.Systematic molecular dynamic simulations were conducted to clarify the strengthening e...Nanoscale segregation of alien solute atoms at the grain boundary(GB)can enhance the stability and mechanical properties of the GB.Systematic molecular dynamic simulations were conducted to clarify the strengthening effect of Cu segregation on AlΣ9(221)[110]GB.The as-predicted negative segregation energy suggests the strong inclination of Cu segregation at Al GBs.Such segregation is expected to improve GB stability and strength.Detailed structural analysis during the uniaxial tensile test indicates that Cu segregation can reduce the free volume of GB atoms and restrict GB atomic displacement,thereby retarding dislocation nucleation and increasing the tensile strength of the GB.The suppressed atomic migrations by Cu doping also give rise to the exceptional stability of E structures at GB,which can retain their kite shape against structural transition during straining.With Cu segregation,the pattern of dislocation nucleation from GB was shifted from“shuffling-assisted regime”to the“collective-migration regime”,wherein the latter necessitates higher critical stress.Further,Cu-doping was also shown to elevate the GB shear strength via blocking the shear-coupled GB migration when subjected to shear deformation.The enhanced GB resistance against shear straining is attributed to the stabilized E structures with Cu segregation featuring reduced atomic free volume.This study provides atomic-scale insights into the stabilizing and strengthening effect of Cu segregation on Al GBs.展开更多
Carbon-supported single-atom catalysts(C-SACs)have been demonstrated as a strategy to promote the reversible conversion reaction of metal sulfide anodes in sodium-ion batteries(SIBs).However,the design principle of pr...Carbon-supported single-atom catalysts(C-SACs)have been demonstrated as a strategy to promote the reversible conversion reaction of metal sulfide anodes in sodium-ion batteries(SIBs).However,the design principle of promising C-SACs remains lacking for obtaining highly reversible metal sulfide anodes.We designed a phosphorus-doped carbon-supported single-atom Mn catalyst(PC-SAMn)with an asymmetrical dual active center.The sulfiphilic Mn and sodiophilic P active centers adsorb discharged Na 2S through Mn-S d-p and P-Na s-p orbital hybridizations.The asymmetrical dual active center induced the asymmetrical adsorption configuration of Na 2S,which efficiently weakened Na-S bond strength and facilitated the decomposition of Na 2S during charging.As a result,the designed catalyst enables typical MoS_(2) with a record-high compositional reversible degree of 89.61%and a low capacity decay ratio of only 0.18%per 100 cycles during 2000 cycles.The research establishes the“orbital hybridization-molecular structure-catalytic activity”relationship for guiding the design of highly reversible conversion-type materials.展开更多
基金support by the National Natural Science Foundation of China(Grant Nos.U23A20546 and 52271010)the Chinese National Natural Science Fund for Distinguished Young Scholars(Grant No.52025015)the Natural Science Foundation of Tianjin City(No.21JCZDJC00510).
文摘1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain boundaries(GBs),which restricts local plastic flow dur-ing the plastic deformation and leads to stress concentration[3,4].Recently,the development of concepts aimed at achieving hetero-geneous grain has emerged as a promising approach for enhanc-ing comprehensive mechanical properties[5,6].
基金financial support of the National Key R&D Program of China(No.SQ2024YFA1200082)the National Natural Science Foundation of China(No.52371013)the Natural Science Foundation of Tianjin City(No.22JCZDJC00020).
文摘The rapid expansion of marine industries has created an urgent demand for advanced engineering materials with superior multifunctional performance.While Cu-Ni alloys demonstrate favorable stability and tribological characteristics,their practical applications are constrained by compromised thermal conductivity and insufficient mechanical strength due to the solid solution of a high amount of Ni in the Cu matrix.Cu-Ni matrix composites reinforced with hexagonal boron nitride(h-BN)have garnered significant attention due to their potential for tailored mechanical and thermal properties.However,challenges such as BN agglomerations in Cu-Ni matrix and poor interfacial bonding hinder their practical applications.To address these limitations,this study proposes an innovative fabrication strategy for boron nitride nanosheets(BNNSs)reinforced Cu-Ni composites by integrating the in situ synthesis of BNNSs on Cu powders via chemical vapor deposition with powder metallurgy.Benefited by the in situ strategy,BNNSs with high crystallinity distribute uniformly within the Cu matrix and have an intimate interfacial bonding without voids or other types of defects.Remarkably,the BNNSs/Cu-30%Ni composite achieves simultaneous enhancement in strength and ductility,exhibiting an ultimate tensile strength of 417 MPa and fracture elongation of 17.5%,representing 30%and 118%improvements over pure Cu-Ni alloys,respectively.This exceptional mechanical synergy originates from threefold strengthening mechanisms:grain refinement,mobile dislocation pinning,and efficient stress transfer via robust interfaces.The microstructural analysis confirms that homogenous distribution of BNNSs optimized stress distribution,mitigating strain localization in the composites.Fractographic examination demonstrates uniformly distributed dimples containing embedded BNNSs,indicative of effective crack bridging and deflection during failure.Furthermore,the composite possesses excellent corrosion resistance comparable to matrix alloys,while achieving 21.23%enhancement in thermal conductivity and 20%reduction in coefficient of friction.The scalable fabrication protocol successfully resolves longstanding challenges in BNNSs dispersion and interfacial bonding,offering a viable pathway for designing high-performance CMCs for marine applications.
基金financially supported by the National Natural Science Foundation of China(Nos.52172222 and 51972226)the National Natural Science Foundation of Tianjin City(No.20JCZDJC00570).
文摘The composites prepared by combining lightweight carbon materials with magnetic metals have demonstrated excellent dielectric and magnetic properties,indicating potential applications in the field of electromagnetic wave(EMW)absorption.However,the rational microstructure design and component optimization of these composites in regulating their magnetic-dielectric balance to achieve high-performance EMW absorption remains challenging.Herein,hierarchical yolk-shell Fe@SiO_(2)@NC composites with dual impedance matching layers and dual built-in electric fields were prepared by self-template aggregation and in situ reduction strategies.The introduction of a SiO_(2)wave-transparent layer into a conventional dielectric-magnetic system has resulted in the successful realization of nanoscale precise impedance matching regulation in absorbers,thereby enabling effective ultra-wideband EMW absorption.The dual impedance matching layers of the internal void layer and the SiO_(2)wave-transparent layer facilitate multiple scattering and reflection of EMWs within the absorbers,and the dual built-in electric fields of Fe/SiO_(2)and SiO_(2)/NC can effectively enhance interfacial polarization effect to attenuate EMWs.The predominantly optimized Fe@SiO_(2)@NC-2 exhibits an ultra-wide effective absorption bandwidth(EAB)of 7.10 GHz and an impressive minimum reflection loss(RL_(min))of−64.83 dB,indicating that optimizing the impedance matching via quantitative design can maximize the EMW absorption performance.This work provides a straightforward yet effective approach for constructing multi-component materials with hierarchical yolk-shell structure,which offers valuable insight into the microstructure design and component optimization of innovative EMW absorption materials.
基金the National Natural Science Foundation of China(Grant Nos.51771130,51531004,and 51422104)the Tianjin youth talent support program+1 种基金the Tianjin Natural Science Funds for Distinguished Young(Grant No.17JCJQJC44300)the Tianjin Science and Technology Support Project(Grant No.17ZXCLGX00060)。
文摘To synthesize graphene economically and efficiently,as well as to improve the interface bonding between graphene and metal and to recede the aggregation issue of graphene,in this work,an easy and scalable bottom-up strategy for the mass production of metal nanoparticles modified graphene nanoplates(GNPs)was proposed.Cu nanoparticles modified GNPs(Cu-GNPs)and Ni nanoparticles modified GNPs(Ni-GNPs)were fabricated through this method,and then compounded with Al via ball milling technique.The asobtained Ni-GNPs/Al composite showed simultaneously improved strength and toughness compared with unreinforced Al,while the Cu-GNPs/Al composite presented a greater strengthening effect.The microstructure and interface of the two composites were carefully characterized and investigated to reveal the difference.First principle study was also adopted to explore the binding energy of different interface structures.This study could provide new insights into the fabrication of GNPs and the control of interface in GNPs/Al composites.
基金supported by the National Natural Science Foundation of China(51272173,51002188)the National Basic Research Program of China(2010CB934703)Tianjin Municipal Science and Technology Commission(12ZCZDGX00800)
文摘Three types of carbon nano-onions（CNOs） including Ni@CNOs.Fe3C@CNOs and Fe0.64Ni0.36@CNOs nanoparticles have been synthesized by catalytic decomposition of methane at 850 ℃ using nickel,iron and iron-nickel alloy catalysts.Comparative and systematic studies have been carried out on the morphology,structural characteristics and graphitic crystallinity of these CNOs products.Furthermore,the electrochemical hydrogen storage properties of three types of CNOs have been investigated.Measurements show that the Ni@CNOs have the highest discharge capacity of 387.2 mAh/g,coiTesponding to a hydrogen storage of 1.42%.This comparison study shows the advantages of each catalyst in the growth of CNOs.enabling the controllable synthesis and tuning the properties of CNOs by mediating different metals and their alloy for using in the fuel cell system.
基金This work was financially supported by the Chinese Na-tional Natural Science Fund for Distinguished Young Scholars(No.52025015)the Chinese National Natural Science Foundation Nos.51771130,52071230 and 52101181)+2 种基金the Tianjin Youth Tal-ent Support Program,the Tianjin Natural Science Funds for Dis-tinguished Young Scholars(No.17JCJQJC44300)the Tianjin Sci-ence and Technology Support Project(No.17ZXCLGX00060)the China Postdoctoral Science Foundation Nos.2020M670648 and 2021T140505).
文摘The deformation incompatibility of components is a bottleneck restricting the exaltation of the strength and ductility of composites.Herein,the coherent transition interface was designed and produced in hexagonal boron nitride nanosheets(BNNSs)/Al composites by reaction sintering route,expecting to re-lieve the deformation incompatibility between BNNSs and Al.It is demonstrated that with the sintering temperature for composites raising from 600℃ to 650℃,700℃ and 750℃,different interface bonding characteristics,which involve nucleation and growth of AlN continuous nanolayer,were confirmed.Fur-thermore,first-principles calculations show that the generation of the coherent transition interface im-proved the interfacial bonding strength of BNNSs/Al composites through covalent bonds.The composites with coherent transition interface exhibit excellent strength-toughness combination in tensile and impact tests.The finite element simulation and in-situ approach under tensile tests were applied to investigate the influence of transition interface structure on deformation behavior of BNNSs/Al composite.It is found that the generation of the transition interface can not only weaken the stress partitioning behavior in the elastic stage,but also constrain the crack initiation and propagation behavior in the elastic-plastic stage and plastic stage,thereby improving the deformation compatibility between BNNSs and Al.The present work provides a novel view into the breakthrough for the trade-offrelationship of strength and ductility by coherent transition interface design in nanocomposites.
基金financially supported by the National Natural Science Funds for Excellent Young Scholar(Grant No.51422104)the National Natural Science Foundation of China(Grant Nos.51531004,51771130 and 51472177)the Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No.201145)
文摘In order to improve the interface wettability as well as the interfacial bonding between graphene and copper matrix,in this work,graphene nanoplates modified with nickel nanoparticles(Ni-GNPs)were synthesized using a one-step method based on spray-drying and chemical vapor deposition.Thereafter,0.33 wt%Ni-GNPs were introduced into copper matrix composite by the molecular-level mixing method,leading to further enhancement of 90%in yield strength.This is attributed to the presence of Ni-GNPs,which provided high resistance to matrix against deformation.In addition,with the modification of nickel at the interface,the wettability and interfacial bonding between graphene nanoplates and copper matrix were improved,which enhanced the load transfer then.Furthermore,the microstructures and strengthening mechanisms were investigated and discus sed meanwhile.
基金financially supported by the National Natural Science Foundation of China(No.51971242)the Tianjin Science and Technology Planning Project(No.20YDTPJC01600)。
文摘The integrity and regularity of pore morphology play an important role in determining the mechanical properties of the metallic foam materials.The conventional methods on refining pore morphology are mainly focused on the optimization of fabrication techniques,however,they are usually inconvenient and complicated.Recently,incorporating nano reinforcement is considered to be a suitable way to fabricate metallic composite foams accompanied by optimized pore morphology and enhanced mechanical properties.In this work,through a facile and rapid powder metallurgy foaming method,the aluminum-silicon(Al-Si)alloy composite foams reinforced by graphene nanosheets(GNSs)are successfully fabricated.The microstructure analyses reveal that,for the Al-Si alloy foams incorporating the GNSs(GNSs/Al-Si composite foams),the pore size is transformed to be smaller,the pore size distributions become more homogeneous and the pore shape is also refined to a regular and roundish state.Meanwhile,the shape of Si precipitates is found transforming from an irregular long strip(length of~20μm,width of~5μm)to a fine particle state(diameter of~5μm).Moreover,the compressive testing results show that,the 0.4wt%GNSs/Al-Si composite foams own the optimal compression stress of 11.7±0.5 MPa,plateau stress of 10.0±1.0 MPa and energy absorption capacity of 6.8±0.7 MJ/m^(3),which have improvement of 58.1%,53.8%and 51.1%in comparison with the Al-Si alloy foams counterpart,respectively.The present findings may pave a new way for developing new generation of metallic composite foams that with stable microstructure and excellent mechanical performance.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51771130,51531004,and 51422104)the Tianjin youth talent support program+1 种基金the Tianjin Natural Science Funds for Distinguished Young Scholars(Grant No.17JCJQJC44300)the Tianjin Science and Technology Support Project(Grant No.17ZXCLGX00060)。
文摘In this study,Cu nanoparticles-coated graphene nanoplatelets(Cu-NPs@GNPs)were synthesized by a simple in situ method with the assistance of Na Cl templates and used for reinforcing Al–10 Si composites through stir casting process.The experimental results showed that the coating of Cu-NPs on the GNPs could compromise the density mismatch between GNPs and metal matrix and eff ectively hinder the float of GNPs during stirring.The reaction of Cu-NPs and Al matrix could protect the structural integrity of GNPs as well as improve the interfacial wettability between GNPs and the matrix,thus promoting the uniform dispersion of GNPs in the composites.As a result,the as-prepared 0.5 wt%Cu-NPs@GNPs/Al–10 Si composite exhibited a tensile strength of 251 MPa(45%higher than the Al–10 Si)with a total elongation of 15%.The strengthening eff ects were mainly attributed to the following three reasons:Firstly,the Cu-NPs coating improved the interfacial bonding between GNPs and Al matrix which promoted the load transfer from the matrix to the GNPs.Secondly,the nanoscale Al 2 Cu formed by the reaction of Cu-NPs and Al matrix played a role in precipitation strengthening.Thirdly,GNPs refined the silicon phases and improved the monolithic performances of the composites.
基金financially support by the Equipment Advance Research Fund (Grant No. 61409220102)the Chinese National Science Fund for Distinguished Young Scholars (Grant No. 52025015)+2 种基金the Chinese National Natural Science Foundation (Grant No. 51771130, 52071230)the Tianjin youth talent support program, the Tianjin Natural Science Funds for Distinguished Young Scholars (Grant No. 17JCJQJC44300)the Tianjin Science and Technology Support Project (Grant No. 17ZXCLGX00060)。
文摘Microstructural and mechanical behavior of heat treatable Al-4.6Cu binary alloy reinforced with graphene nanoplates(GNPs) in different heat treatment status were investigated in this paper.The addition of GNPs significantly enhanced the yield strength and tensile strength of Al-Cu alloy regardless of the heattreatment conditions.It was also found that GNPs accelerated the formation of precipitates,leading to a greatly shortened aging time for GNPs/Al-4.6Cu composite to reach the peak hardness.However,aging treatment enhanced the strength of GNPs/Al-Cu composite very little,which could be explained by the interaction between GNPs,precipitates and dislocations.This work inspires us that the heat treatment process of aluminum alloy matrix composites should be designed independently with the matrix in quest of an optimum performance.
基金funded by the Shandong Provincial Natural Science Foundation,China(ZR2022QH147,ZR2022QH165)the Innovation Team and Talents Cultivation Program of National Administration of Traditional Chinese Medicine(No.ZYYCXTD-D-202005).
文摘Huangqin tea(HQT),derived from the aerial parts of various Scutellaria species,in particular S.baicalensis Georgi,has a long history of traditional use in China.Its significance has grown in recent years due to its potential anti-aging,colon cancer chemopreventive,and cardiovascular protective properties.Huangqin tea source plants have identified over 295 chemical constituents,including flavonoids,essential oils,phenolic acids,sterols,diterpenes,polysaccharides,and amino acids.Pharmacological research has underscored the diverse beneficial effects of Huangqin tea and flavonoid extracts.These effects encompass anti-inflammatory,antiviral,anti-bacterial,antipyretic,and analgesic properties,along with neuroprotective effects and protection against cardiovascular and cerebrovascular diseases.Safety studies indicate that HQT is generally safe within recommended dosages and historical use.HQT presents multifaceted potential health benefits,though comprehensive research is necessary to ensure its effectiveness and safety in human applications.
基金supported by the National Natural Science Foundation of China (51972225)。
文摘The Sabatier principle has been widely used for designing electrocatalysts for energy conversion applications,but it is rarely mentioned in the research of cathode catalyst of Li-CO_(2) batteries.In our work,the"volcanic"relationship between the catalytic activity and the adsorption energy of the catalyst to the intermediates is first demonstrated based on the first-principles calculation,which meets the Sabatier principle and can be used to design the cathode catalysts.The increases in the number of nitrogenvacancy in WN shift the d-band center and increase the interaction with the reactants.The catalytic activity increases first and then decreases with the increase of adsorption energy,which was proved in the experiment.The optimal catalyst for moderate adsorption of intermediate makes the thin LiaCO_(3) distribute evenly.It exhibits a median voltage difference of 0.68 V and an energy efficiency of 84.33%at20μA cm^(-2)with a limited capacity of 200μA h cm^(-2).
基金financially supported by the Chinese National Natural Science Fund for Distinguished Young Scholars(No.52025015)the National Natural Science Foundation of China(Nos.51771130,52071230,52101181)+3 种基金the Tianjin Youth Talent Support Program,the Tianjin Natural Science Funds for Distinguished Young Scholars(No.17JCJQJC44300)the Tianjin Science and Technology Support Project(No.17ZXCLGX00060)the China Postdoctoral Science Foundation(Nos.2020M670648 and 2021T140505)the Joint Fund of Ministry of Education for Equipment Pre-Research(No.6141A02033230)。
文摘The structural deterioration caused by the relatively weak out-of-plane bending stiffness and the chemically-active edge area of graphene limits its outperformance in strengthening for Al matrix composites(AMCs).Introducing one-dimensional(1D)carbon nanotubes(CNTs)to graphene/metal system is one of the promised strategies to complement the weakness of 2D graphene and make full use of the outstanding intrinsic properties of the both reinforcements.To date,such synergistic strengthening and toughening mechanisms are largely unknown.In this study,AMCs reinforced by a novel hybrid reinforcement,i.e.,graphene nanosheets decorated with Cu nanoparticles and CNTs(Cu@GNS-CNTs),are fabricated by an in-situ synthesis method.The combined contrast experiments validated that the organically integrated reinforcing structure promotes the intrinsic load bearing capacity of GNS and the strain hardening capability of the Al matrix simultaneously.As a result,the composites achieved excellent tensile strength and uniform elongation with almost no loss.The strengthening mechanism originated primarily from the hybrid reinforcement exhibits superior load-transfer,fracture inhibition and dislocation storage capability by controlling the interface reaction to construct an effective interface structure without damaging the reinforcement.Our work identifies a promising structural modification strategy for 2D materials and provides mechanistic insights into the synergistic strengthening effect of graphene/CNTs hybrid reinforcement.
基金the National Natural Science Foundation of China under Grant 52130105.
文摘1.Introduction To mitigate the distressing problem of mutual exclusion between mechanical properties-electrical conductivity(EC)in Cu alloy and meet the multiple requirements on properties,suitable ad-ditive phases with combined extraordinary performance have commonly been utilized to endow Cu matrix composites with comprehensive properties[1-4].Promoting dislocation-phase boundary interactions and interfacial bonding enables markedly altering the strength of composites through phase boundary strengthening and loading transfer.
基金financially supported by the Joint Fund Project of Equipment Pre-research of Education Ministry(Grant No.6141A02033230)。
文摘The construction and application of traditional high-strength 7075 aluminum alloy(Al7075) through selective laser melting(SLM) are currently restricted by the serious hot cracking phenomenon. To address this critical issue, in this study, Si is employed to assist the SLM printing of high-strength Al7075. The laser energy density during SLM is optimized, and the eff ects of Si element on solidification path, relative density, microstructure and mechanical properties of Al7075 alloy are studied systematically. With the modified solidification path, laser energy density, and the dense microstructure with refined grain size and semi-continuous precipitates network at grain boundaries, which consists of fine Si, β-MgSi, Q-phase and θ-AlCu, the hot cracking phenomenon and mechanical properties are eff ectively improved. As a result, the tensile strength of the SLM-processed Si-modified Al7075 can reach 486 ± 3 MPa, with a high relative density of ~ 99.4%, a yield strength of 291 ± 8 MPa, fracture elongation of(6.4 ± 0.4)% and hardness of 162 ± 2(HV) at the laser energy density of 112.5 J/mm~3. The main strengthening mechanism with Si modification is demonstrated to be the synergetic enhancement of grain refinement, solution strengthening, load transfer, and dislocation strengthening. This work will inspire more new design of high-strength alloys through SLM.
基金financial support by the National Natural Science Foundation of China(Nos.51771130,51531004,and 51422104)the Tianjin Youth Talent Support Program,the Tianjin Natural Science Funds for Distinguished Young(No.17JCJQJC44300)+1 种基金the Tianjin Science and Technology Support Project(No.17ZXCLGX00060)the China Postdoctoral Science Foundation(No.2020M670649)。
文摘The development of sodium-ion(SIBs)and potassium-ion batteries(PIBs)has increased rapidly because of the abundant resources and cost-effectiveness of Na and K.Antimony(Sb)plays an important role in SIBs and PIBs because of its high theoretical capacity,proper working voltage,and low cost.However,Sb-based anodes have the drawbacks of large volume changes and weak charge transfer during the charge and discharge processes,thus leading to poor cycling and rapid capacity decay.To address such drawbacks,many strategies and a variety of Sb-based materials have been developed in recent years.This review systematically introduces the recent research progress of a variety of Sb-based anodes for SIBs and PIBs from the perspective of composition selection,preparation technologies,structural characteristics,and energy storage behaviors.Moreover,corresponding examples are presented to illustrate the advantages or disadvantages of these anodes.Finally,we summarize the challenges of the development of Sb-based materials for Na/K-ion batteries and propose potential research directions for their further development.
基金supported by the financial support from the National Natural Science Foundation of China (Nos.52271010,52201162,and 52101181)the Natural Science Foundation of Tianjin City (key program,No.21JCZDJC00510)the China Postdoctoral Science Foundation (No.2022M712344).
文摘1.Introduction Driven by the engineering application of transportation and aerospace,simultaneously achieving excellent mechanical properties and corrosion resistance are urgently required for the next-generation Al matrix composites(AMCs)[1,2].
基金supported by the National Key Research and Development Program of China(2024YFA1209800)the National Natural Science Foundation of China(52422103,52271010,52001224)。
文摘Nanoscale segregation of alien solute atoms at the grain boundary(GB)can enhance the stability and mechanical properties of the GB.Systematic molecular dynamic simulations were conducted to clarify the strengthening effect of Cu segregation on AlΣ9(221)[110]GB.The as-predicted negative segregation energy suggests the strong inclination of Cu segregation at Al GBs.Such segregation is expected to improve GB stability and strength.Detailed structural analysis during the uniaxial tensile test indicates that Cu segregation can reduce the free volume of GB atoms and restrict GB atomic displacement,thereby retarding dislocation nucleation and increasing the tensile strength of the GB.The suppressed atomic migrations by Cu doping also give rise to the exceptional stability of E structures at GB,which can retain their kite shape against structural transition during straining.With Cu segregation,the pattern of dislocation nucleation from GB was shifted from“shuffling-assisted regime”to the“collective-migration regime”,wherein the latter necessitates higher critical stress.Further,Cu-doping was also shown to elevate the GB shear strength via blocking the shear-coupled GB migration when subjected to shear deformation.The enhanced GB resistance against shear straining is attributed to the stabilized E structures with Cu segregation featuring reduced atomic free volume.This study provides atomic-scale insights into the stabilizing and strengthening effect of Cu segregation on Al GBs.
基金supported by the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(2022QNRC001)the Natural Science Foundation of Tianjin City(23JCZDJC01110)+5 种基金the National Natural Science Foundation of China(51972225 and 52202281)the Tianjin University Science and Technology Innovation Leading Talent Training Programthe Natural Science Foundation of Chongqing(CSTB2023NSCQ-MSX0538)the Natural Science Basic Research Program of Shaanxi(2024JC-YBQN-0073)the Young Talent Fund of Association for Science and Technology in Shaanxi(20230101)the Innovation Capability Support Program of Shaanxi-Science and Technology Innovation Team Project(2025RS-CXTD-024)。
文摘Carbon-supported single-atom catalysts(C-SACs)have been demonstrated as a strategy to promote the reversible conversion reaction of metal sulfide anodes in sodium-ion batteries(SIBs).However,the design principle of promising C-SACs remains lacking for obtaining highly reversible metal sulfide anodes.We designed a phosphorus-doped carbon-supported single-atom Mn catalyst(PC-SAMn)with an asymmetrical dual active center.The sulfiphilic Mn and sodiophilic P active centers adsorb discharged Na 2S through Mn-S d-p and P-Na s-p orbital hybridizations.The asymmetrical dual active center induced the asymmetrical adsorption configuration of Na 2S,which efficiently weakened Na-S bond strength and facilitated the decomposition of Na 2S during charging.As a result,the designed catalyst enables typical MoS_(2) with a record-high compositional reversible degree of 89.61%and a low capacity decay ratio of only 0.18%per 100 cycles during 2000 cycles.The research establishes the“orbital hybridization-molecular structure-catalytic activity”relationship for guiding the design of highly reversible conversion-type materials.
