The low strength of Mg-Li alloys sets a limit to lightweight applications.Introducing crystal defects(twins,dislocations,and SFs)is a distinctive strategy for maintaining good mechanical properties of metallic materia...The low strength of Mg-Li alloys sets a limit to lightweight applications.Introducing crystal defects(twins,dislocations,and SFs)is a distinctive strategy for maintaining good mechanical properties of metallic materials.A lamellar-structured Mg-4Li-3Al-0.4Ca alloy with high performance was prepared by hot extrusion and rotary swaging.The as-swaged alloy exhibits excellent mechanical properties with tensile strength,yield strength,elongation to failure,and specific strength of 391 MPa,312 MPa,14.2%,and 238.4 kN m kg^(-1),respectively.The average grain size of the as-swaged alloy is 160±23 nm,and the microstructure is mainly composed of lamellar structures,twins,ultrafine grains,and nano-grains.The abundant lamellar structures and twins promote the storage of dislocations and SFs,leading to the formation of twin-twin interactions and enhancing strain hardening.The formation of UFG and NG by dynamic recrystallization further improves the yield strength.Shearable second phases play a critical role in enhancing the yield strength and ductility.More importantly,extensive planar dislocation glide and(c+a)dislocations efficiently relax the local stress concentrations,and thus improve the ductility.展开更多
In this paper,the nonlinear dynamics of a curved pipe is investigated in the case of principal parametric resonance due to pulsating flow and impact with loose supports.The coupled in-plane and out-of-plane governing ...In this paper,the nonlinear dynamics of a curved pipe is investigated in the case of principal parametric resonance due to pulsating flow and impact with loose supports.The coupled in-plane and out-of-plane governing equations with the consideration of von Karman geometric nonUnearity are presented and discretized via the differential quadrature method（DQM）.The nonlinear dynamic responses are calculated numerically to demonstrate the influence of pulsating frequency.Finally,the impact is taken into consideration.The influence of clearance on frettingwear damage,such as normal work rate,contact ratio and impact force level,is demonstrated.展开更多
Lithium(Li)dendrite formation/evolution with its disastrous safety issues has been challenging in high-energy Li-metal batteries.The detrimental Li dendrite is primarily initiated by an inhomogeneous distribution of c...Lithium(Li)dendrite formation/evolution with its disastrous safety issues has been challenging in high-energy Li-metal batteries.The detrimental Li dendrite is primarily initiated by an inhomogeneous distribution of current density that results in uncontrollable Li deposition in the vertical direction.To suppress the Li dendrite formation through selective Li infusion and uniform Li deposition,a unique Janus-structured surface consisting of Zn@Li layer and Ag layers was fabricated on carbon cloth(CC)by step-wise magnetron sputtering.The lower-half Zn layer,enabling selective Li infusion and the rational formation of a Zn@Li layer,was able to regulate the loading amounts of Li metal.Simultaneously,the upper-half lithiophilic Ag layer and derived AgLi layer prevented the vertical Li growth due to a uniform Li deposition.Importantly,the bifunctional surface design guaranteed a sustainable exposure of lithiophilic sites upon Li nucleation/evolution.Interestingly,the symmetrical cells and full cells utilizing the Janus-structured CC@Zn@Li/Ag anode exhibited superior cycling stability and rate capability.We believe that this novel design on the Janus-structured Li anode can advance the development of safe and durable Limetal batteries.展开更多
Nitrides MAX have attracted ever-growing interest owing to its unique metallic and ceramic characteristics and properties.Here,we report on the synthesis of highly purified Ti_(2)AlN and Ti_(4)AlN_(3) powders from Ti,...Nitrides MAX have attracted ever-growing interest owing to its unique metallic and ceramic characteristics and properties.Here,we report on the synthesis of highly purified Ti_(2)AlN and Ti_(4)AlN_(3) powders from Ti,Al and TiN powders by a facile atmosphere sintering method.The obtained nitrides show highly pure phase and excellent layered structure.Except for the composition difference of raw materials,both the nitrides can be sintered and obtained by same sintering temperature and holding time,which thus makes less processing time and less usage of synthesis parameters as compared to previously synthesis methods.To our knowledge,present work is one of the few reports on synthesis of Ti_(4)AlN_(3) and Ti_(2)AlN using atmosphere sintering method.Furthermore,the lattice changes of the layered structure of Ti_(2)AlX(X/C=N)were studied by changing the composition of X position from the synthesis of Ti_(2)AlCN and Ti_(2)AlC,and the optimal formulation and synthesis mechanism of Ti_(4)AlN_(3) were also studied.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52371093 and 52171104)the National Key Research and Development Program of China(No.2021YFB3701100)the Chongqing Research Program of Basic Research and Frontier Technology,China(Nos.CSTB2023NSCQ-BSX0036 and cstc2021ycjh-bgzxm0086).
文摘The low strength of Mg-Li alloys sets a limit to lightweight applications.Introducing crystal defects(twins,dislocations,and SFs)is a distinctive strategy for maintaining good mechanical properties of metallic materials.A lamellar-structured Mg-4Li-3Al-0.4Ca alloy with high performance was prepared by hot extrusion and rotary swaging.The as-swaged alloy exhibits excellent mechanical properties with tensile strength,yield strength,elongation to failure,and specific strength of 391 MPa,312 MPa,14.2%,and 238.4 kN m kg^(-1),respectively.The average grain size of the as-swaged alloy is 160±23 nm,and the microstructure is mainly composed of lamellar structures,twins,ultrafine grains,and nano-grains.The abundant lamellar structures and twins promote the storage of dislocations and SFs,leading to the formation of twin-twin interactions and enhancing strain hardening.The formation of UFG and NG by dynamic recrystallization further improves the yield strength.Shearable second phases play a critical role in enhancing the yield strength and ductility.More importantly,extensive planar dislocation glide and(c+a)dislocations efficiently relax the local stress concentrations,and thus improve the ductility.
文摘In this paper,the nonlinear dynamics of a curved pipe is investigated in the case of principal parametric resonance due to pulsating flow and impact with loose supports.The coupled in-plane and out-of-plane governing equations with the consideration of von Karman geometric nonUnearity are presented and discretized via the differential quadrature method（DQM）.The nonlinear dynamic responses are calculated numerically to demonstrate the influence of pulsating frequency.Finally,the impact is taken into consideration.The influence of clearance on frettingwear damage,such as normal work rate,contact ratio and impact force level,is demonstrated.
基金supported financially by the National Key Research and Development Program of China(grant no.2021YFB2400202)the National Natural Science Foundation of China(grant no.52104313)+1 种基金the Key Research and Development Plan of Shaanxi(grant no.2024GH-YBXM-11)the Foshan Science and Technology Innovation Team Project(grant no.1920001004098).
文摘Lithium(Li)dendrite formation/evolution with its disastrous safety issues has been challenging in high-energy Li-metal batteries.The detrimental Li dendrite is primarily initiated by an inhomogeneous distribution of current density that results in uncontrollable Li deposition in the vertical direction.To suppress the Li dendrite formation through selective Li infusion and uniform Li deposition,a unique Janus-structured surface consisting of Zn@Li layer and Ag layers was fabricated on carbon cloth(CC)by step-wise magnetron sputtering.The lower-half Zn layer,enabling selective Li infusion and the rational formation of a Zn@Li layer,was able to regulate the loading amounts of Li metal.Simultaneously,the upper-half lithiophilic Ag layer and derived AgLi layer prevented the vertical Li growth due to a uniform Li deposition.Importantly,the bifunctional surface design guaranteed a sustainable exposure of lithiophilic sites upon Li nucleation/evolution.Interestingly,the symmetrical cells and full cells utilizing the Janus-structured CC@Zn@Li/Ag anode exhibited superior cycling stability and rate capability.We believe that this novel design on the Janus-structured Li anode can advance the development of safe and durable Limetal batteries.
基金This work was supported by the National Natural Science Foundation of China(61774122)the Science and Technol-ogy Developing Project of Shaanxi Province(2015KW-001)the 111 Project of China(B14040).
文摘Nitrides MAX have attracted ever-growing interest owing to its unique metallic and ceramic characteristics and properties.Here,we report on the synthesis of highly purified Ti_(2)AlN and Ti_(4)AlN_(3) powders from Ti,Al and TiN powders by a facile atmosphere sintering method.The obtained nitrides show highly pure phase and excellent layered structure.Except for the composition difference of raw materials,both the nitrides can be sintered and obtained by same sintering temperature and holding time,which thus makes less processing time and less usage of synthesis parameters as compared to previously synthesis methods.To our knowledge,present work is one of the few reports on synthesis of Ti_(4)AlN_(3) and Ti_(2)AlN using atmosphere sintering method.Furthermore,the lattice changes of the layered structure of Ti_(2)AlX(X/C=N)were studied by changing the composition of X position from the synthesis of Ti_(2)AlCN and Ti_(2)AlC,and the optimal formulation and synthesis mechanism of Ti_(4)AlN_(3) were also studied.
