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
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
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
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 introduction of fillers boosts the performance of polymer coatings and extends their service life.However,single component fillers are not sufficient for intelligent coatings,and compatibility between the polymer ...The introduction of fillers boosts the performance of polymer coatings and extends their service life.However,single component fillers are not sufficient for intelligent coatings,and compatibility between the polymer matrix and the filler remains a major challenge.In this study,functional polydopamine(PDA)modified CeO_(2)/sodium-based montmorillonite(Na-MMT)or CeO_(2)/calcium-based montmorillonite(Ca-MMT)fillers were designed and fabricated via facile in-situ method.The coatings incorporated with MMT-based fillers that were prepared demonstrated remarkable anti-corrosion capabilities,exceptional antimicrobial resistance,and rapid selfhealing properties.Specific ally,the low-frequency impedance(|Z|_(0.01Hz))values of PDA/CeO_(2)/Na-MMT/EP and PDA/CeO_(2)/Ca-MMT/EP,after being immersed for 30 days,were sustained at 2.24×10^(7)and 1.70×10^(7)Ωcm^(2),respectively.Additionally,the bacteriostatic rates of the filler against E.coli and S.aureus can both reach above 99.9%,respectively,due to the photothermal effect and synergistic bacteriostatic mechanism of PDA and CeO_(2).The scratches healed rapidly within 40 s under near-infrared(NIR)irradiation.This work provides valuable guidance for the utilization of MMT-based sheet fillers for enhanced corrosion-resistant,antimicrobial,and repairable coatings.展开更多
Multiparent advanced generation inter-cross(MAGIC)populations improve the accuracy of quantitative trait loci mapping compared to biparental populations by increasing diversity and reducing linkage disequilibrium betw...Multiparent advanced generation inter-cross(MAGIC)populations improve the accuracy of quantitative trait loci mapping compared to biparental populations by increasing diversity and reducing linkage disequilibrium between variants.Here we describe the development of two MAGIC populations derived from a cross of 11 founder lines from the INTA(National Institute for Agricultural Technology in Argentina)sunflower breeding program.The founder lines are fertility maintainer inbred lines that exhibit genetic diversity in several traits,including flowering cycle,plant architecture,disease resistance,oil content and oil quality.The crossing scheme applied follows the design of two-way,four-way and eight-way crosses with a modification to increase the number of recombinations and shorten the linkage disequilibrium.Phenotyping a subset of F_(2)families and F_5 lines for different traits shows an increase in the diversity of the analyzed traits compared to the parental lines.In addition,we identified lines with transgressive segregation for Sunflower Verticillium Wilt resistance.These results confirm that the MAGIC populations will serve as unique genetic and genomic resources to better characterize the genetics of complex traits and identify potentially superior alleles for sunflower breeding.It will also enrich the gene pool of fertility maintainers(A/B line)of the sunflower germplasm and facilitate the introduction of new breeding methods to select female parents for use in AxR combinations to obtain superior sunflower hybrids.展开更多
Precipitation at grain boundaries is typically not regarded as an efficient method for strengthening materials since it can induce grain boundary embrittlement, which detrimentally affects ductility. In this research,...Precipitation at grain boundaries is typically not regarded as an efficient method for strengthening materials since it can induce grain boundary embrittlement, which detrimentally affects ductility. In this research, we developed a multi-principal element alloy (MPEA) with the composition Cr_(30)Co_(30)Ni_(30)Al_(5)Ti_(5) (at.%), incorporating both intragranular and intergranular nanoprecipitates. Utilizing multiscale, three-dimensional, and in-situ electron microscopy techniques, coupled with computational simulations, we established that intergranular nanoprecipitation in this material plays a crucial role in enhancing strength and promoting dislocation plasticity. The structure of intergranular nanoprecipitation comprises multiple phases with varying composition and structure. Despite the diversity, the crystal planes conducive to the easy glide of dislocations are well-matched, allowing for the sustained continuity of dislocation slipping across different phase structures. Simultaneously, this structure generates an undulated stress field near grain boundaries, amplifying the strengthening effect and facilitating multiple slip and cross-slip during deformation. Consequently, it promotes the proliferation and storage of dislocations. As a result, our material exhibits a yield strength of approximately 1010 MPa and an ultimate tensile strength of around 1500 MPa, accompanied by a significant fracture elongation of 41 %. Our findings illuminate the potential for harnessing intergranular nanoprecipitation to optimize the strength-ductility trade-off in MPEAs, emphasizing the strategy of leveraging complex compositions for the design of sophisticated functional microstructures.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(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financially supported by the National Natural Science Foundation of China(No.52261045)Hainan Provincial Natural Science Foundation of China(No.625QN266)the Scientific Research Starting Foundation of Hainan University(No.XJ2400005319)
文摘The introduction of fillers boosts the performance of polymer coatings and extends their service life.However,single component fillers are not sufficient for intelligent coatings,and compatibility between the polymer matrix and the filler remains a major challenge.In this study,functional polydopamine(PDA)modified CeO_(2)/sodium-based montmorillonite(Na-MMT)or CeO_(2)/calcium-based montmorillonite(Ca-MMT)fillers were designed and fabricated via facile in-situ method.The coatings incorporated with MMT-based fillers that were prepared demonstrated remarkable anti-corrosion capabilities,exceptional antimicrobial resistance,and rapid selfhealing properties.Specific ally,the low-frequency impedance(|Z|_(0.01Hz))values of PDA/CeO_(2)/Na-MMT/EP and PDA/CeO_(2)/Ca-MMT/EP,after being immersed for 30 days,were sustained at 2.24×10^(7)and 1.70×10^(7)Ωcm^(2),respectively.Additionally,the bacteriostatic rates of the filler against E.coli and S.aureus can both reach above 99.9%,respectively,due to the photothermal effect and synergistic bacteriostatic mechanism of PDA and CeO_(2).The scratches healed rapidly within 40 s under near-infrared(NIR)irradiation.This work provides valuable guidance for the utilization of MMT-based sheet fillers for enhanced corrosion-resistant,antimicrobial,and repairable coatings.
基金supported by a doctoral grant from the National Scientific and Technical Research Council(Consejo Nacional de Investigaciones Científicas y T ecnicas,CONICET)the National Institute of Agricultural Technology(INTA)+1 种基金by projects funded by INTA(CP_2019–2023 I-114,I-127,I-090/2023–2025 I-111,I-87)Agencia Nacional de Promocio n Científica y T ecnica(PICT 2017N?2523)。
文摘Multiparent advanced generation inter-cross(MAGIC)populations improve the accuracy of quantitative trait loci mapping compared to biparental populations by increasing diversity and reducing linkage disequilibrium between variants.Here we describe the development of two MAGIC populations derived from a cross of 11 founder lines from the INTA(National Institute for Agricultural Technology in Argentina)sunflower breeding program.The founder lines are fertility maintainer inbred lines that exhibit genetic diversity in several traits,including flowering cycle,plant architecture,disease resistance,oil content and oil quality.The crossing scheme applied follows the design of two-way,four-way and eight-way crosses with a modification to increase the number of recombinations and shorten the linkage disequilibrium.Phenotyping a subset of F_(2)families and F_5 lines for different traits shows an increase in the diversity of the analyzed traits compared to the parental lines.In addition,we identified lines with transgressive segregation for Sunflower Verticillium Wilt resistance.These results confirm that the MAGIC populations will serve as unique genetic and genomic resources to better characterize the genetics of complex traits and identify potentially superior alleles for sunflower breeding.It will also enrich the gene pool of fertility maintainers(A/B line)of the sunflower germplasm and facilitate the introduction of new breeding methods to select female parents for use in AxR combinations to obtain superior sunflower hybrids.
基金supported by the National Science Fund for Distinguished Young Scholars of China(No.52325102)the Natural Science Foundation of Zhejiang Province,China(No.LZ22E010001)the National Key R&D Program of China(No.2023YFB2405802).
文摘Precipitation at grain boundaries is typically not regarded as an efficient method for strengthening materials since it can induce grain boundary embrittlement, which detrimentally affects ductility. In this research, we developed a multi-principal element alloy (MPEA) with the composition Cr_(30)Co_(30)Ni_(30)Al_(5)Ti_(5) (at.%), incorporating both intragranular and intergranular nanoprecipitates. Utilizing multiscale, three-dimensional, and in-situ electron microscopy techniques, coupled with computational simulations, we established that intergranular nanoprecipitation in this material plays a crucial role in enhancing strength and promoting dislocation plasticity. The structure of intergranular nanoprecipitation comprises multiple phases with varying composition and structure. Despite the diversity, the crystal planes conducive to the easy glide of dislocations are well-matched, allowing for the sustained continuity of dislocation slipping across different phase structures. Simultaneously, this structure generates an undulated stress field near grain boundaries, amplifying the strengthening effect and facilitating multiple slip and cross-slip during deformation. Consequently, it promotes the proliferation and storage of dislocations. As a result, our material exhibits a yield strength of approximately 1010 MPa and an ultimate tensile strength of around 1500 MPa, accompanied by a significant fracture elongation of 41 %. Our findings illuminate the potential for harnessing intergranular nanoprecipitation to optimize the strength-ductility trade-off in MPEAs, emphasizing the strategy of leveraging complex compositions for the design of sophisticated functional microstructures.
