As-cast alloys often require complex thermomechanical processing to obtain a hierarchical structure to achieve a good combination of strength and ductility.Here in this work,a novel hierarchical Fe_(27)Ni_(35)Cr_(18.2...As-cast alloys often require complex thermomechanical processing to obtain a hierarchical structure to achieve a good combination of strength and ductility.Here in this work,a novel hierarchical Fe_(27)Ni_(35)Cr_(18.25)Al_(13.75)Co_(2)Ti_(2)Mo_(2) high-entropy alloy(HEA)with ultra-high tensile strength and excellent ductility was fabricated by direct casting.The as-cast alloy exhibits hierarchical structure with an ul-trafine lamellar microstructure(ULM),ultrafine rhombus microstructure(URM),ultrafine vermicular mi-crostructure(UVM),nanosized precipitates and spinodal decomposition(SP)that develops during casting and cooling.The incompatibility of face-centered cubic(FCC)and body-centered cubic(BCC)phases in the deformation process leads to heterogeneous deformation-induced(HDI)hardening,which brings the alloy a tensile yield strength(YS)of~1056 MPa,an ultimate tensile strength(UTS)of~1526 MPa and a total elongation(El)of~15.6%.Additionally,the numerous interfaces generated by the hierarchical structure absorb the energy during deformation,effectively retarding the dislocation motion and causing strong work-hardening.展开更多
The development and deployment of aluminum conductor have been significantly hampered by the contradiction of yield strength,uniform elongation,and electrical conductivity.Herein,we successfully fabricated a pure alum...The development and deployment of aluminum conductor have been significantly hampered by the contradiction of yield strength,uniform elongation,and electrical conductivity.Herein,we successfully fabricated a pure aluminum(Al)clad aluminum alloy(AA)rod with hierarchical compositions and microstructures.The proposed pure Al clad AA rod showcases an optimized combination of yield strength,uniform elongation,and electrical conductivity,i.e.,easing the restriction on improving yield strength,uniform elongation,and electrical conductivity.Compared to existing experiments,uniform elongation improved fourfold,while yield strength increased by 13%and electrical conductivity improved by 2%in terms of the international annealed copper standard(IACS).Microstructural characterizations and theoretical analyses revealed that the optimal performance of the Al clad AA arose from low-density low-angle grain boundaries(LAGBs)in the outer Al and high-density LAGBs with nanoscale precipitations in the inner AA.Our findings offer a compelling strategy for fabricating high-performance aluminum conductors,thereby laying a solid technical foundation for their wide application in power delivery systems.展开更多
Microstructural evolution and deformation mechanism of a metastableβalloy(Ti-10 V-2 Fe-3 Al)processed by rotationally accelerated shot peening(RASP)were systematically investigated with optical microscopy,X-ray diffr...Microstructural evolution and deformation mechanism of a metastableβalloy(Ti-10 V-2 Fe-3 Al)processed by rotationally accelerated shot peening(RASP)were systematically investigated with optical microscopy,X-ray diffraction,electron backscatter diffraction and transmission electron microscopy.Different gradient hierarchical microstructures(gradients inα″martensite andβphase,and hierarchical twins range from the nanoscale to microscale)can be fabricated by RASP via changing the shot peening time.The hardening behavior and tensile mechanical properties of gradient hierarchical microstructure were systematically explored.Novel deformation twinning systems of{112}α″and{130}<310>α″in the kinkedα″martensite were revealed during the tensile deformation.It was found that stress-induced martensitic transformation,twinnedα″martensite and the related dynamic grain refinement contribute to hardness and work hardening ability.Simultaneous improvement of strength and ductility of the metastableα″titanium alloy can be achieved by introducing a gradient hierarchical microstructure.展开更多
Developing efficient and stable photocatalysts for hydrogen generation still remains a huge challenge.Herein,we adopted Cynanchum fibers as a carbon source and substrate to construct a ternary hollow core-shell carbon...Developing efficient and stable photocatalysts for hydrogen generation still remains a huge challenge.Herein,we adopted Cynanchum fibers as a carbon source and substrate to construct a ternary hollow core-shell carbon microtubes@TiO_(2)/ZnIn_(2)S_(4)(denoted as CMT@TiO_(2)/ZnIn_(2)S_(4))for photothermal-assisted photocatalytic hydrogen evolution(PHE).For the catalyst system,ZnIn_(2)S_(4)is the main visible light absorber,TiO_(2) is introduced to form a heterojunction with ZnIn_(2)S_(4)to facilitate the separation of photogenerated carriers,and hollow CMT derived from Cynanchum fibers serves as a conductive scaffold and a photothermal core to elevate the surface temperature of the localized reaction system.Benefiting from the rationally designed multicomponents and microstructures,the photocatalyst proposed enhanced PHE activity of 9.71 mmol·g^(−1)·h^(−1),which was 30.3,2.7 and 1.5 times higher than those of binary CMT@TiO_(2),pristine ZnIn_(2)S_(4)and TiO_(2)/ZnIn_(2)S_(4)composite,respectively.The outperformed PHE activity of CMT@TiO_(2)/ZnIn_(2)S_(4)could be ascribed to the synergy of the formation of intimate heterointerface,the CMT-induced photothermal effect and the hierarchical core-shell architecture.This work provides a promising approach for constructing efficient and durable photocatalysts for H_(2) evolution.展开更多
We employed the extended self-consistent field theory to investigate the supramolecular self-assembly behaviors of asymmetric diblock copolymer blends(AB/B’C)with hydrogen bonding interactions between shorter B and B...We employed the extended self-consistent field theory to investigate the supramolecular self-assembly behaviors of asymmetric diblock copolymer blends(AB/B’C)with hydrogen bonding interactions between shorter B and B’blocks.The hydrogen bonding interactions are described by Yukawa potentials,where the hydrogen bonding donors and acceptors were modelled as two blocks smeared with opposite screened charges.The hierarchical microstructures with parallelly packed lamellae-in-lamellae(Lam)and 4.8.8 Archimedean tilting pattern(4.8.8)were observed at lower and higher hydrogen bonding density(θ),respectively.The hierarchy of Lam and 4.8.8 were demonstrated by the one-and two-dimensional density profiles and the underlying order of the large-length-scale and small-length-scale microstructures were also clarified.It was found that the 4.8.8 is favorable to the stronger hydrogen bonding density or interactions.Asθincreases,the microphase transition from Lam to 4.8.8 occurs atθ=0.34,which is mainly attributed to the optimization of the electrostatic energy and conformational entropy with sacrificing the interfacial energy.This work can provide a new strategy to understand the supramolecular self-assembly as well as the mechanism behind the formation of complex hierarchical microstructures.展开更多
Softening behavior of lath martensitic steels is related to the coarsening of laths and dislocation evolution during cyclic deformation.Involving the physical mechanism,we developed a dislocation-based model to study ...Softening behavior of lath martensitic steels is related to the coarsening of laths and dislocation evolution during cyclic deformation.Involving the physical mechanism,we developed a dislocation-based model to study the cyclic plastic response for lath martensitic steels.For a block,we proposed an interfacial dislocation evolution model to physically present the interaction between mobile dislocations in the block and interfacial dislocations by considering the coarsening mechanism of the laths.Moreover,the evolution behavior of backstress caused by dislocation pile up at the block boundary has been considered.Then,a hierarchical model based on the elastic-viscoplastic self-consistent(EVPSC)theory is developed,which can realize the scale transition among representative volume element(RVE),prior austenite grains(PAGs)and blocks.According to the proposed model,the effective mechanical responses including the cyclic hysteretic loop and peak stress at different cycles for lath martensitic steel have been theoretically predicted and investigated.展开更多
Developing acid/base-resistant and low-price microwave-absorbing materials with lighter weight is highly desired for practical applications in extreme environments.Herein,we demonstrate the successful synthesis of the...Developing acid/base-resistant and low-price microwave-absorbing materials with lighter weight is highly desired for practical applications in extreme environments.Herein,we demonstrate the successful synthesis of the N-doped porous carbon(NC)material with hierarchical pore structure by the spray pyrolysis method.The large specific surface area(SBET=707.53 m^(2)·g^(−1))of materials enables multiple scattering of incident electromagnetic waves,and N doping greatly enhances the electrical conductivity of the material.Notably,single-atom Zn can adjust the local electronic structure of adjacent sites such as carbon and nitrogen atoms,induce the center of polarization,and thus change the dielectric and electronic properties of the host material.The porous carbon coating of single-atom Zn avoids the deterioration of electromagnetic parameters caused by the accumulation of magnetic particles under high-temperature pyrolysis.At the same time,they can also be used in various complex environments,such as acidic and basic environments.Ultimately,NC-1000,with high surface area,low density,and good chemical stability,obtained a minimum reflection loss(RLmin)of−50.5 dB and an effective absorption bandwidth(EAB)exceeding 5.1 GHz at the thickness of 1.9 mm.After soaking in the strong acid and base solution,the electromagnetic wave absorption performance of the material decreased by<15%.Widely available raw materials and a simple preparation scheme are expected to expedite industrial mass production for this novel type of materials.展开更多
Peculiar hierarchical microstructures in creatures inspire modern material design with distinct functionalities.Creatures can effortlessly construct sophisticated yet long-range ordered microstructure across bio-membr...Peculiar hierarchical microstructures in creatures inspire modern material design with distinct functionalities.Creatures can effortlessly construct sophisticated yet long-range ordered microstructure across bio-membrane through ion secretion and precipitation.However,microstructure biomimicry in current technology generally requires elaborate,point-by-point fabrication.Herein,a spontaneous yet controllable strategy is developed to achieve surface microstructure engineering through a natural surface phenomenon similar to ion secretion-precipitation,that is,coupled dissolution-precipitation.A series of hierarchical microstructures on mineral surfaces in fluids with tunable morphology,orientation,dimension,and spatial distribution are achieved by simply controlling initial dissolution and fluid chemistry.In seawater,long-range ordered film of vertically aligned brucite flakes forms through interfacial dissolution,nucleation,and confinement-induced orientation of flakes with vertically grown{110}plane,on the edge of which,fusiform aragonite epitaxially precipitates.With negligible initial surface dissolution,prismatic aragonite epitaxially grows on a calcite polyhedron-packed surface.By tuning fluid chemistry,closely packed calcite polyhedron and loosely packed calcite micro-pillars are engineered through rapid and retarded precipitation,respectively.Surprisingly,the spontaneously grown microstructures resemble those deliberately created by human or found in nature,and tremendously modulate surface functionality.These findings open new possibilities for facile and customizable engineering of microstructural surfaces,hierarchical heterostructures,and biomimetic materials.展开更多
基金J.C.Niu and Z.Q.Fu acknowledge the financial support from the National Natural Science Foundation of China(No.52103360)from the Pearl River Talent Program(No.2021QN02C766)+1 种基金from the Basic and Applied Basic Research Foundation of Guangdong Province(No.2020A1515111104)W.P.Chen thanks the financial support from the Key-Area Research and Development Program of Guangdong Province(No.2018B090905002)。
文摘As-cast alloys often require complex thermomechanical processing to obtain a hierarchical structure to achieve a good combination of strength and ductility.Here in this work,a novel hierarchical Fe_(27)Ni_(35)Cr_(18.25)Al_(13.75)Co_(2)Ti_(2)Mo_(2) high-entropy alloy(HEA)with ultra-high tensile strength and excellent ductility was fabricated by direct casting.The as-cast alloy exhibits hierarchical structure with an ul-trafine lamellar microstructure(ULM),ultrafine rhombus microstructure(URM),ultrafine vermicular mi-crostructure(UVM),nanosized precipitates and spinodal decomposition(SP)that develops during casting and cooling.The incompatibility of face-centered cubic(FCC)and body-centered cubic(BCC)phases in the deformation process leads to heterogeneous deformation-induced(HDI)hardening,which brings the alloy a tensile yield strength(YS)of~1056 MPa,an ultimate tensile strength(UTS)of~1526 MPa and a total elongation(El)of~15.6%.Additionally,the numerous interfaces generated by the hierarchical structure absorb the energy during deformation,effectively retarding the dislocation motion and causing strong work-hardening.
基金supported by the National Natural Science Foundation of China(Nos.12072327,12302497)the National Outstanding Youth Science Fund Project(No.12125206)+2 种基金Major International Joint Research Project(No.W2411003)Fund raised by China Electric Power Research Institute(No.GC80-21-002)CAS Project for Young Scientists in Basic Research(YSBR-096).
文摘The development and deployment of aluminum conductor have been significantly hampered by the contradiction of yield strength,uniform elongation,and electrical conductivity.Herein,we successfully fabricated a pure aluminum(Al)clad aluminum alloy(AA)rod with hierarchical compositions and microstructures.The proposed pure Al clad AA rod showcases an optimized combination of yield strength,uniform elongation,and electrical conductivity,i.e.,easing the restriction on improving yield strength,uniform elongation,and electrical conductivity.Compared to existing experiments,uniform elongation improved fourfold,while yield strength increased by 13%and electrical conductivity improved by 2%in terms of the international annealed copper standard(IACS).Microstructural characterizations and theoretical analyses revealed that the optimal performance of the Al clad AA arose from low-density low-angle grain boundaries(LAGBs)in the outer Al and high-density LAGBs with nanoscale precipitations in the inner AA.Our findings offer a compelling strategy for fabricating high-performance aluminum conductors,thereby laying a solid technical foundation for their wide application in power delivery systems.
基金supported financially by the Scientific Challenge Project of China(No.TZ2018001)the National Natural Science Foundation of China(No.11627901)。
文摘Microstructural evolution and deformation mechanism of a metastableβalloy(Ti-10 V-2 Fe-3 Al)processed by rotationally accelerated shot peening(RASP)were systematically investigated with optical microscopy,X-ray diffraction,electron backscatter diffraction and transmission electron microscopy.Different gradient hierarchical microstructures(gradients inα″martensite andβphase,and hierarchical twins range from the nanoscale to microscale)can be fabricated by RASP via changing the shot peening time.The hardening behavior and tensile mechanical properties of gradient hierarchical microstructure were systematically explored.Novel deformation twinning systems of{112}α″and{130}<310>α″in the kinkedα″martensite were revealed during the tensile deformation.It was found that stress-induced martensitic transformation,twinnedα″martensite and the related dynamic grain refinement contribute to hardness and work hardening ability.Simultaneous improvement of strength and ductility of the metastableα″titanium alloy can be achieved by introducing a gradient hierarchical microstructure.
基金supported by the National Natural Science Foundation of China(No.21701078)the PhD Initiation Foundation of Liaocheng University(No.318052140).
文摘Developing efficient and stable photocatalysts for hydrogen generation still remains a huge challenge.Herein,we adopted Cynanchum fibers as a carbon source and substrate to construct a ternary hollow core-shell carbon microtubes@TiO_(2)/ZnIn_(2)S_(4)(denoted as CMT@TiO_(2)/ZnIn_(2)S_(4))for photothermal-assisted photocatalytic hydrogen evolution(PHE).For the catalyst system,ZnIn_(2)S_(4)is the main visible light absorber,TiO_(2) is introduced to form a heterojunction with ZnIn_(2)S_(4)to facilitate the separation of photogenerated carriers,and hollow CMT derived from Cynanchum fibers serves as a conductive scaffold and a photothermal core to elevate the surface temperature of the localized reaction system.Benefiting from the rationally designed multicomponents and microstructures,the photocatalyst proposed enhanced PHE activity of 9.71 mmol·g^(−1)·h^(−1),which was 30.3,2.7 and 1.5 times higher than those of binary CMT@TiO_(2),pristine ZnIn_(2)S_(4)and TiO_(2)/ZnIn_(2)S_(4)composite,respectively.The outperformed PHE activity of CMT@TiO_(2)/ZnIn_(2)S_(4)could be ascribed to the synergy of the formation of intimate heterointerface,the CMT-induced photothermal effect and the hierarchical core-shell architecture.This work provides a promising approach for constructing efficient and durable photocatalysts for H_(2) evolution.
基金financially supported by the Natural Science Foundation of Shanghai(No.21ZR1402800)the Fundamental Research Funds for the Central Universities(No.2232020D-11)+1 种基金the China Postdoctoral Science Foundation(No.2021M690597)the Open Project Program of Fujian Provincial Key Laboratory of Textiles Inspection Technology(Fujian Fiber Inspection Center)(Nos.2020-MXJ-04)。
文摘We employed the extended self-consistent field theory to investigate the supramolecular self-assembly behaviors of asymmetric diblock copolymer blends(AB/B’C)with hydrogen bonding interactions between shorter B and B’blocks.The hydrogen bonding interactions are described by Yukawa potentials,where the hydrogen bonding donors and acceptors were modelled as two blocks smeared with opposite screened charges.The hierarchical microstructures with parallelly packed lamellae-in-lamellae(Lam)and 4.8.8 Archimedean tilting pattern(4.8.8)were observed at lower and higher hydrogen bonding density(θ),respectively.The hierarchy of Lam and 4.8.8 were demonstrated by the one-and two-dimensional density profiles and the underlying order of the large-length-scale and small-length-scale microstructures were also clarified.It was found that the 4.8.8 is favorable to the stronger hydrogen bonding density or interactions.Asθincreases,the microphase transition from Lam to 4.8.8 occurs atθ=0.34,which is mainly attributed to the optimization of the electrostatic energy and conformational entropy with sacrificing the interfacial energy.This work can provide a new strategy to understand the supramolecular self-assembly as well as the mechanism behind the formation of complex hierarchical microstructures.
基金supported by the National Natural Science Foundation of China(Grant Nos.11988102,12002005,11632001,11521202)the Science Challenge Project(Grant No.TZ2018001).
文摘Softening behavior of lath martensitic steels is related to the coarsening of laths and dislocation evolution during cyclic deformation.Involving the physical mechanism,we developed a dislocation-based model to study the cyclic plastic response for lath martensitic steels.For a block,we proposed an interfacial dislocation evolution model to physically present the interaction between mobile dislocations in the block and interfacial dislocations by considering the coarsening mechanism of the laths.Moreover,the evolution behavior of backstress caused by dislocation pile up at the block boundary has been considered.Then,a hierarchical model based on the elastic-viscoplastic self-consistent(EVPSC)theory is developed,which can realize the scale transition among representative volume element(RVE),prior austenite grains(PAGs)and blocks.According to the proposed model,the effective mechanical responses including the cyclic hysteretic loop and peak stress at different cycles for lath martensitic steel have been theoretically predicted and investigated.
基金B.X.thanks financial support from the National Natural Science Foundation of China(No.21801133)the Jiangsu Specially Appointed Professorship and Innovation and Entrepreneurship Talents in Jiangsu Province,the State Key Laboratory of Coordination Chemistry,the School of Chemistry and Chemical Engineering,and Collaborative Innovation Center of Advanced Microstructures,Nanjing University.
文摘Developing acid/base-resistant and low-price microwave-absorbing materials with lighter weight is highly desired for practical applications in extreme environments.Herein,we demonstrate the successful synthesis of the N-doped porous carbon(NC)material with hierarchical pore structure by the spray pyrolysis method.The large specific surface area(SBET=707.53 m^(2)·g^(−1))of materials enables multiple scattering of incident electromagnetic waves,and N doping greatly enhances the electrical conductivity of the material.Notably,single-atom Zn can adjust the local electronic structure of adjacent sites such as carbon and nitrogen atoms,induce the center of polarization,and thus change the dielectric and electronic properties of the host material.The porous carbon coating of single-atom Zn avoids the deterioration of electromagnetic parameters caused by the accumulation of magnetic particles under high-temperature pyrolysis.At the same time,they can also be used in various complex environments,such as acidic and basic environments.Ultimately,NC-1000,with high surface area,low density,and good chemical stability,obtained a minimum reflection loss(RLmin)of−50.5 dB and an effective absorption bandwidth(EAB)exceeding 5.1 GHz at the thickness of 1.9 mm.After soaking in the strong acid and base solution,the electromagnetic wave absorption performance of the material decreased by<15%.Widely available raw materials and a simple preparation scheme are expected to expedite industrial mass production for this novel type of materials.
基金National Key R&D Program of China,Grant/Award Number:2021YFB2600900National Science Fund for Distinguished Young Scholars of China,Grant/Award Number:51925903+3 种基金National Natural Science Foundation of China,Grant/Award Numbers:52108195,U21A20150Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20210264Natural Sciences and Engineering Research Council of CanadaCanada Research Chairs Program。
文摘Peculiar hierarchical microstructures in creatures inspire modern material design with distinct functionalities.Creatures can effortlessly construct sophisticated yet long-range ordered microstructure across bio-membrane through ion secretion and precipitation.However,microstructure biomimicry in current technology generally requires elaborate,point-by-point fabrication.Herein,a spontaneous yet controllable strategy is developed to achieve surface microstructure engineering through a natural surface phenomenon similar to ion secretion-precipitation,that is,coupled dissolution-precipitation.A series of hierarchical microstructures on mineral surfaces in fluids with tunable morphology,orientation,dimension,and spatial distribution are achieved by simply controlling initial dissolution and fluid chemistry.In seawater,long-range ordered film of vertically aligned brucite flakes forms through interfacial dissolution,nucleation,and confinement-induced orientation of flakes with vertically grown{110}plane,on the edge of which,fusiform aragonite epitaxially precipitates.With negligible initial surface dissolution,prismatic aragonite epitaxially grows on a calcite polyhedron-packed surface.By tuning fluid chemistry,closely packed calcite polyhedron and loosely packed calcite micro-pillars are engineered through rapid and retarded precipitation,respectively.Surprisingly,the spontaneously grown microstructures resemble those deliberately created by human or found in nature,and tremendously modulate surface functionality.These findings open new possibilities for facile and customizable engineering of microstructural surfaces,hierarchical heterostructures,and biomimetic materials.
