马氏体分数和第二相纳米颗粒的数量对钢的力学性能至关重要。本文通过液氮淬火并进行时效(liquid nitrogen quenching and aged,LNQ-A)处理,成功获得了屈服强度高达2 GPa的Fe-18Ni-5Mo-2Cr-2Ti-1.2Al-0.8V-0.2Si马氏体时效钢,并同时保...马氏体分数和第二相纳米颗粒的数量对钢的力学性能至关重要。本文通过液氮淬火并进行时效(liquid nitrogen quenching and aged,LNQ-A)处理,成功获得了屈服强度高达2 GPa的Fe-18Ni-5Mo-2Cr-2Ti-1.2Al-0.8V-0.2Si马氏体时效钢,并同时保留8%的良好延伸率。作为对比,水淬并进行时效处理(water quenching and aged,WQ-A)的样品其屈服强度仅为1.5 GPa,这是由于其在淬火过程中马氏体相变不彻底的缘故。通过透射电子显微镜,揭示了WQ-A和LNQ-A的样品中均形成了大量的纳米级η-Ni_(3)Ti析出相。然而,在WQ-A的样品中观察到残余或反转奥氏体,且马氏体基体中析出相的数量较LNQ-A的少。此外,LNQ-A样品的马氏体基体中存在大量的位错,这也是钢的力学性能显著提升的另一原因。因此,采用深冷处理和简单时效工艺,是提高马氏体时效钢的强度并保留良好延伸率的有效方法。展开更多
The lattice parameter,measured with sufficient accuracy,can be utilized to evaluate the quality of single crystals and to determine the equation of state for materials.We propose an iterative method for obtaining more...The lattice parameter,measured with sufficient accuracy,can be utilized to evaluate the quality of single crystals and to determine the equation of state for materials.We propose an iterative method for obtaining more precise lattice parameters using the interaction points for the pseudo-Kossel pattern obtained from laser-induced X-ray diffraction(XRD).This method has been validated by the analysis of an XRD experiment conducted on iron single crystals.Furthermore,the method was used to calculate the compression ratio and rotated angle of an LiF sample under high pressure loading.This technique provides a robust tool for in-situ characterization of structural changes in single crystals under extreme conditions.It has significant implications for studying the equation of state and phase transitions.展开更多
Oxygen reduction reaction(ORR)in neutral electrolyte is urgently needed in various areas,such as metalair batteries.However,the N-coordinated transition-metal single-atom electrocatalysts confront sluggish catalytic k...Oxygen reduction reaction(ORR)in neutral electrolyte is urgently needed in various areas,such as metalair batteries.However,the N-coordinated transition-metal single-atom electrocatalysts confront sluggish catalytic kinetics due to the inappropriate electronic structure and the as-resulted unreasonable adsorption strength towards oxygen-containing intermediates.In this work,we develop a strategy to tune the Fe d-orbital spin state by introducing inert Si atom into the first coordination sphere of Fe-N_(4)moieties.The experimental and theoretical results suggest that Si atom generates the coordination field distortion of Fe and induces the Fe d-orbital spin state transforming from low to medium spin state.The optimized spin-electron filled state(t2g^(4)eg^(1))of Fe sites weakens the adsorption strength to intermediates and reduces the energy barrier of^(∗)OH desorption.Consequently,Fe-Si/NC catalyst exhibits superior ORR performance compared with that of Fe-NC and commercial Pt/C,showing a more positive half-wave potential of 0.753 V(vs.RHE)in 0.1 mol/L phosphate buffered saline.In addition,Fe-Si/NC-based neutral zinc-air batteries show a maximum power density of 108.9 mW cm^(−2)and long-term stability for 200 h.This work represents the possibility of constructing distorted coordination configurations of single-atom catalysts to modulate electronic structure and enhance ORR activity in neutral electrolyte.展开更多
The Al-Cu alloy is a historical model alloy system in the physical metallurgy of engineering aluminum al-loys.Nevertheless,a few fundamental phenomena of phase transformation occurring in this simple alloy are still n...The Al-Cu alloy is a historical model alloy system in the physical metallurgy of engineering aluminum al-loys.Nevertheless,a few fundamental phenomena of phase transformation occurring in this simple alloy are still not adequately understood.Among all,for instance,the formation mechanisms of its key harden-ingθ'-phase remain mysterious.There is strong evidence thatθ'-precipitates can form from a different high-temperature precipitation pathway,while their formation mechanism via the conventional pathway well-known since 1938 remains to be clarified.Using state-of-the-art electron microscopy,here we report a secondary high-temperature precipitation pathway ofθ'-precipitates.It is demonstrated that led by a secondary high-temperature precursor,namedθ'_(S-HTP),very fineθ'-precipitates can form in the unde-formed bulk Al-Cu alloys at elevated temperatures(≥250℃).Interestingly is that with Sc-microalloying the surviving rate of meta-stableθ'_(S-HTP) precipitates increases drastically and the formedθ'-precipitates become much finer,significantly enhancing the alloys’strength and thermal stability.It is also revealed that aθ'_(S-HTP) precipitate can genetically evolve into aθ'-precipitate without having to change its mor-phology and orientation.Our study provides new insights into understanding the industry bulk alloys’microstructures and properties.展开更多
Despite extensive investigation into various electrocatalysts to enhance the progressive redox transformations of sulfur species in Li-S batteries(LSBs),their catalytic abilities are often hindered by suboptimal adsor...Despite extensive investigation into various electrocatalysts to enhance the progressive redox transformations of sulfur species in Li-S batteries(LSBs),their catalytic abilities are often hindered by suboptimal adsorption-desorption dynamics and slow charge transfer.Herein,a representative Co_(0.1)Mo_(0.9)P/MXene heterostructure electrocatalyst with optimal p-band centers and interfacial charge redistribution is engineered as a model to expedite bidirectional redox kinetics of sulfur via appropriate Co doping and built-in electric field(BIEF)effect.Theoretical and experimental results corroborate that the optimal Co-doping level and BIEF heterostructure ad-justs the p-band center of active phosphorus sites in Co_(0.1)Mo_(0.9)P/MXene to optimize the adsorption properties and catalytic performance of sulfur species,the BIEF between Co_(0.1)Mo_(0.9)P and MXene significantly decreases the activation energy as well as Gibbs free energy of rate-determining step,accelerates interfacial electron/Li-transfer rate during cycling,thereby accelerating dual-directional sulfur catalytic conversion rate in LSBs.Consequently,the S/Co_(0.1)Mo_(0.9)P/MXene cathode attains a large initial capacity of 1357 mAh g^(-1)at 0.2 C and a 500-cycle long stability(0.071%decay rate per cycle)at 0.5 C.Impressively,the high-loading S/Co_(0.1)Mo_(0.9)P/MXene cathode(sulfur loading:5.2 mg cm^(-2))also presents a remarkable initial areal capacity(6.5 mAh cm^(-2))with superior cycling stability under lean electrolyte(4.8μL mg_(sulfur)^(-1))conditions,and its Li-S pouch cell delivers a high capacity of 1029.4 mAh g^(-1).This study enhances the comprehension of catalyst effect in Li-S chemistry and provides important guidelines for designing effective dual-directional Li-S catalysts.展开更多
The development of cost-effective and energy-efficient anode materials is essential for the advancement of industrial water electrolysis.Herein,we report a rapid,ambient-temperature method to prepare largearea nickel ...The development of cost-effective and energy-efficient anode materials is essential for the advancement of industrial water electrolysis.Herein,we report a rapid,ambient-temperature method to prepare largearea nickel mesh electrodes(SFN/NM)via surface functionalization completed within 3 min,without relying on thermal treatments or noble metals.The as-prepared electrodes achieve a high current density of 100 m A/cm^(2)at an overpotential of just 300 m V in 6 mol/L KOH,and exhibit remarkable stability over1600 h of continuous operation.With comparable activity to commercial Raney nickel yet significantly lower processing and material costs(reduced by 50%-70%),this approach provides a practical solution for low-energy water splitting.Beyond its industrial relevance,the strategy offers a scalable model for engineering high-performance OER electrodes,inspiring future directions in electrocatalyst design.展开更多
Electromagnetic wave(EMW)absorbers with anti-corrosion property are highly desired to enhance the durability of military targets in harsh condition.Herein,cross-link NiAl-layered double hydroxide(NiAl-LDH)nanosheets o...Electromagnetic wave(EMW)absorbers with anti-corrosion property are highly desired to enhance the durability of military targets in harsh condition.Herein,cross-link NiAl-layered double hydroxide(NiAl-LDH)nanosheets on the inner/outer surfaces of carbon microtubes(CMTs)are ingeniously constructed through the combination of atomic layer deposition technique and a hydrothermal method.The obtained NiAl-LDH/CMT composite exhibits excellent EMW absorption and corrosion resistance performance.The large internal cavity of CMT significantly enhances impedance matching.The uniform distribution of NiAl-LDH nanosheets on both the inner and outer surfaces of CMT generates numerous heterogeneous inter-faces that induce substantial polarization loss.Consequently,at a filler rate of only 5 wt.%,the NiAl-LDH/CMT composite exhibits a minimum reflection loss of−60.2 dB and a maximum effective absorp-tion bandwidth of 5.9 GHz.In addition,the combined high impermeability of CMT and the effective Cl^(-)-trapping ability of NiAl-LDH endows NiAl-LDH/CMT composite with outstanding corrosion protection property in simulated seawater environment.Furthermore,the PO_(4)^(3-)anions are effectively incorporated into the NiAl-LDH interlayer via anion exchange,which can further enhance corrosion protection capac-ity through surface inactivation from slow-release PO_(4)^(3-)anions without reducing their EMW absorption performance.In summary,this work can give guidance for the development of efficient anti-corrosion EMW absorption materials.展开更多
Upon ageing of a deformed metal,compositional segregation to dislocations and stacking faults is well known to elevate strength.However,Suzuki segregation effects typically result in a modest strength in-crease on the...Upon ageing of a deformed metal,compositional segregation to dislocations and stacking faults is well known to elevate strength.However,Suzuki segregation effects typically result in a modest strength in-crease on the order of 10 MPa for many substitutional face-centered-cubic solid solutions.Severe pre-deformation can lead to significant hardening but often at the cost of substantial tensile ductility af-ter subsequent aging.Here we propose a novel strategy to improve the Suzuki hardening effect in a single-phase CoCrNi alloy by meticulously controlling repetitive straining and annealing conditions with-out compromising ductility.Our findings revealed that multiple stages of annealing along the way of pre-straining significantly increase the fraction of dislocations that trap partitioning species(i.e.Cr),far exceeding the levels achievable through single-shot annealing after straight pre-deformation to the same accumulative strain(40%).Thermodynamically,the segregation of Cr into stacking faults is driven by re-duced local stacking fault energy(SEF)and system energy.The decreased SFE inhibits dislocation cross-slip,promotes partial dislocation nucleation,and facilitates dislocation intersection,leading to a high den-sity of extended stacking fault ribbons in the multi-pass strained and annealed samples.As a result,the yield strength increments of multi-pass treated samples(75±10 MPa)are four times higher than those of single-pass treated samples(18±8 MPa),while retaining an adequate strain hardening rate,thus pre-serving tensile ductility despite of plastic flow at higher stresses.Our strategy shows promise for broader applications,particularly in scenarios where conventional thermomechanical treatments fail to yield sat-isfactory results.展开更多
文摘马氏体分数和第二相纳米颗粒的数量对钢的力学性能至关重要。本文通过液氮淬火并进行时效(liquid nitrogen quenching and aged,LNQ-A)处理,成功获得了屈服强度高达2 GPa的Fe-18Ni-5Mo-2Cr-2Ti-1.2Al-0.8V-0.2Si马氏体时效钢,并同时保留8%的良好延伸率。作为对比,水淬并进行时效处理(water quenching and aged,WQ-A)的样品其屈服强度仅为1.5 GPa,这是由于其在淬火过程中马氏体相变不彻底的缘故。通过透射电子显微镜,揭示了WQ-A和LNQ-A的样品中均形成了大量的纳米级η-Ni_(3)Ti析出相。然而,在WQ-A的样品中观察到残余或反转奥氏体,且马氏体基体中析出相的数量较LNQ-A的少。此外,LNQ-A样品的马氏体基体中存在大量的位错,这也是钢的力学性能显著提升的另一原因。因此,采用深冷处理和简单时效工艺,是提高马氏体时效钢的强度并保留良好延伸率的有效方法。
基金National Natural Science Foundation of China(12102410)Fund of National Key Laboratory of Shock Wave and Detonation Physics(JCKYS2022212005)。
文摘The lattice parameter,measured with sufficient accuracy,can be utilized to evaluate the quality of single crystals and to determine the equation of state for materials.We propose an iterative method for obtaining more precise lattice parameters using the interaction points for the pseudo-Kossel pattern obtained from laser-induced X-ray diffraction(XRD).This method has been validated by the analysis of an XRD experiment conducted on iron single crystals.Furthermore,the method was used to calculate the compression ratio and rotated angle of an LiF sample under high pressure loading.This technique provides a robust tool for in-situ characterization of structural changes in single crystals under extreme conditions.It has significant implications for studying the equation of state and phase transitions.
基金financially supported by the National Natural Science Foundation of China(Nos.52422314,U23A20687,and 52231008)the International Science&Technology Cooperation Program of Hainan Province(No.GHYF2023007).
文摘Oxygen reduction reaction(ORR)in neutral electrolyte is urgently needed in various areas,such as metalair batteries.However,the N-coordinated transition-metal single-atom electrocatalysts confront sluggish catalytic kinetics due to the inappropriate electronic structure and the as-resulted unreasonable adsorption strength towards oxygen-containing intermediates.In this work,we develop a strategy to tune the Fe d-orbital spin state by introducing inert Si atom into the first coordination sphere of Fe-N_(4)moieties.The experimental and theoretical results suggest that Si atom generates the coordination field distortion of Fe and induces the Fe d-orbital spin state transforming from low to medium spin state.The optimized spin-electron filled state(t2g^(4)eg^(1))of Fe sites weakens the adsorption strength to intermediates and reduces the energy barrier of^(∗)OH desorption.Consequently,Fe-Si/NC catalyst exhibits superior ORR performance compared with that of Fe-NC and commercial Pt/C,showing a more positive half-wave potential of 0.753 V(vs.RHE)in 0.1 mol/L phosphate buffered saline.In addition,Fe-Si/NC-based neutral zinc-air batteries show a maximum power density of 108.9 mW cm^(−2)and long-term stability for 200 h.This work represents the possibility of constructing distorted coordination configurations of single-atom catalysts to modulate electronic structure and enhance ORR activity in neutral electrolyte.
基金supported by the National Natural Science Foundation of China(Nos.51831004 and 52171006).
文摘The Al-Cu alloy is a historical model alloy system in the physical metallurgy of engineering aluminum al-loys.Nevertheless,a few fundamental phenomena of phase transformation occurring in this simple alloy are still not adequately understood.Among all,for instance,the formation mechanisms of its key harden-ingθ'-phase remain mysterious.There is strong evidence thatθ'-precipitates can form from a different high-temperature precipitation pathway,while their formation mechanism via the conventional pathway well-known since 1938 remains to be clarified.Using state-of-the-art electron microscopy,here we report a secondary high-temperature precipitation pathway ofθ'-precipitates.It is demonstrated that led by a secondary high-temperature precursor,namedθ'_(S-HTP),very fineθ'-precipitates can form in the unde-formed bulk Al-Cu alloys at elevated temperatures(≥250℃).Interestingly is that with Sc-microalloying the surviving rate of meta-stableθ'_(S-HTP) precipitates increases drastically and the formedθ'-precipitates become much finer,significantly enhancing the alloys’strength and thermal stability.It is also revealed that aθ'_(S-HTP) precipitate can genetically evolve into aθ'-precipitate without having to change its mor-phology and orientation.Our study provides new insights into understanding the industry bulk alloys’microstructures and properties.
基金supported by the National Natural Science Foundation of China(No.51972066)the Natural Science Foundation of Guangdong Province of China(No.2024A1515012499).
文摘Despite extensive investigation into various electrocatalysts to enhance the progressive redox transformations of sulfur species in Li-S batteries(LSBs),their catalytic abilities are often hindered by suboptimal adsorption-desorption dynamics and slow charge transfer.Herein,a representative Co_(0.1)Mo_(0.9)P/MXene heterostructure electrocatalyst with optimal p-band centers and interfacial charge redistribution is engineered as a model to expedite bidirectional redox kinetics of sulfur via appropriate Co doping and built-in electric field(BIEF)effect.Theoretical and experimental results corroborate that the optimal Co-doping level and BIEF heterostructure ad-justs the p-band center of active phosphorus sites in Co_(0.1)Mo_(0.9)P/MXene to optimize the adsorption properties and catalytic performance of sulfur species,the BIEF between Co_(0.1)Mo_(0.9)P and MXene significantly decreases the activation energy as well as Gibbs free energy of rate-determining step,accelerates interfacial electron/Li-transfer rate during cycling,thereby accelerating dual-directional sulfur catalytic conversion rate in LSBs.Consequently,the S/Co_(0.1)Mo_(0.9)P/MXene cathode attains a large initial capacity of 1357 mAh g^(-1)at 0.2 C and a 500-cycle long stability(0.071%decay rate per cycle)at 0.5 C.Impressively,the high-loading S/Co_(0.1)Mo_(0.9)P/MXene cathode(sulfur loading:5.2 mg cm^(-2))also presents a remarkable initial areal capacity(6.5 mAh cm^(-2))with superior cycling stability under lean electrolyte(4.8μL mg_(sulfur)^(-1))conditions,and its Li-S pouch cell delivers a high capacity of 1029.4 mAh g^(-1).This study enhances the comprehension of catalyst effect in Li-S chemistry and provides important guidelines for designing effective dual-directional Li-S catalysts.
基金supported by the National Natural Science Foundation of China(Nos.52473299,52201009,52301013 and52231008)the Key Research and Development Program of Hainan Province(No.ZDYF2024GXJS006)+1 种基金International Science&Technology Cooperation Program of Hainan Province(No.GHYF2023007)the Education Department of Hainan Province(No.Hnky2024ZD-2)。
文摘The development of cost-effective and energy-efficient anode materials is essential for the advancement of industrial water electrolysis.Herein,we report a rapid,ambient-temperature method to prepare largearea nickel mesh electrodes(SFN/NM)via surface functionalization completed within 3 min,without relying on thermal treatments or noble metals.The as-prepared electrodes achieve a high current density of 100 m A/cm^(2)at an overpotential of just 300 m V in 6 mol/L KOH,and exhibit remarkable stability over1600 h of continuous operation.With comparable activity to commercial Raney nickel yet significantly lower processing and material costs(reduced by 50%-70%),this approach provides a practical solution for low-energy water splitting.Beyond its industrial relevance,the strategy offers a scalable model for engineering high-performance OER electrodes,inspiring future directions in electrocatalyst design.
基金financially supported by the National Natu-ral Science Foundation of China(Nos.U24A20204,22168016,and 22278101)the Innovation Project for Scientific and Technological Talents in Hainan Province(No.KJRC2023C08)the Innovation Research Team in Hainan Province(No.525CXTD607).
文摘Electromagnetic wave(EMW)absorbers with anti-corrosion property are highly desired to enhance the durability of military targets in harsh condition.Herein,cross-link NiAl-layered double hydroxide(NiAl-LDH)nanosheets on the inner/outer surfaces of carbon microtubes(CMTs)are ingeniously constructed through the combination of atomic layer deposition technique and a hydrothermal method.The obtained NiAl-LDH/CMT composite exhibits excellent EMW absorption and corrosion resistance performance.The large internal cavity of CMT significantly enhances impedance matching.The uniform distribution of NiAl-LDH nanosheets on both the inner and outer surfaces of CMT generates numerous heterogeneous inter-faces that induce substantial polarization loss.Consequently,at a filler rate of only 5 wt.%,the NiAl-LDH/CMT composite exhibits a minimum reflection loss of−60.2 dB and a maximum effective absorp-tion bandwidth of 5.9 GHz.In addition,the combined high impermeability of CMT and the effective Cl^(-)-trapping ability of NiAl-LDH endows NiAl-LDH/CMT composite with outstanding corrosion protection property in simulated seawater environment.Furthermore,the PO_(4)^(3-)anions are effectively incorporated into the NiAl-LDH interlayer via anion exchange,which can further enhance corrosion protection capac-ity through surface inactivation from slow-release PO_(4)^(3-)anions without reducing their EMW absorption performance.In summary,this work can give guidance for the development of efficient anti-corrosion EMW absorption materials.
基金sponsored by the National Key Research and Development Program,Major Scientific Instrument Special Pro-gram for Basic Research-Development and Application of All-domestic Three-dimensional Atom Probe Precision Measurement Instrument Project(No.2023YFF0716200)the State Key Lab-oratory of Powder Metallurgy,Central South University,Changsha,China.Q.Cheng was supported by the China Postdoctoral Science Foundation(No.2023M741111,No.GZC20230752)+2 种基金E.Ma acknowl-edges the National Natural Science Foundation of China(Grant No.52231001)J.Ding was supported by the Natural Science Founda-tion of China(Grant No.12004294)the National Youth Talents Program and the HPC platform of Xi’an Jiaotong University.M.W.Chen was supported by the U.S.National Science Foundation grant DMR-1804320.J.H.Chen acknowledges the financial support from the National Natural Science Foundation of China(No.51831004)。
文摘Upon ageing of a deformed metal,compositional segregation to dislocations and stacking faults is well known to elevate strength.However,Suzuki segregation effects typically result in a modest strength in-crease on the order of 10 MPa for many substitutional face-centered-cubic solid solutions.Severe pre-deformation can lead to significant hardening but often at the cost of substantial tensile ductility af-ter subsequent aging.Here we propose a novel strategy to improve the Suzuki hardening effect in a single-phase CoCrNi alloy by meticulously controlling repetitive straining and annealing conditions with-out compromising ductility.Our findings revealed that multiple stages of annealing along the way of pre-straining significantly increase the fraction of dislocations that trap partitioning species(i.e.Cr),far exceeding the levels achievable through single-shot annealing after straight pre-deformation to the same accumulative strain(40%).Thermodynamically,the segregation of Cr into stacking faults is driven by re-duced local stacking fault energy(SEF)and system energy.The decreased SFE inhibits dislocation cross-slip,promotes partial dislocation nucleation,and facilitates dislocation intersection,leading to a high den-sity of extended stacking fault ribbons in the multi-pass strained and annealed samples.As a result,the yield strength increments of multi-pass treated samples(75±10 MPa)are four times higher than those of single-pass treated samples(18±8 MPa),while retaining an adequate strain hardening rate,thus pre-serving tensile ductility despite of plastic flow at higher stresses.Our strategy shows promise for broader applications,particularly in scenarios where conventional thermomechanical treatments fail to yield sat-isfactory results.
