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Kinetic simulation of early-stage precipitation behavior in Mg-RE binary alloys during aging process

Journal of Magnesium and Alloys 2025年第3期13卷 1078-1087页

作者： Hao Jiang Shao-Xiang Li Long-Long Hao Wei-Jian Li Zhi-Qiang Han Liang-Xing Lv Liang Zhen School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China School of Materials Science and Engineering Chongqing UniversityChongqing 400044China College of Nuclear Equipment and Nuclear Engineering Yantai UniversityYantai 264005China

The precipitation behavior of magnesium-rare earth(Mg-RE)alloys plays a crucial role for their ***,the precipitation happens at small-length and long-time scales,making it challenging to be analyzed by state-of-the-art experimental ***,we combine the advantages of both molecular dynamic forceﬁelds on describing atom interactions and Monte Carlo method on describing diffusive events to develop an embedded atom method(EAM)potential based kinetic Monte Carlo(KMC)*** the proposed model,we simulated the formation and evolution of Y clusters in Mg-Y alloy formed by the vacancy mechanism,and rationalize the simulation results using aberration-corrected scanning transmission electron microscopy *** conducted a systematic analysis of the atomic structure,the evolution kinetics and path of the Y cluster by tracing Y atoms and comparing with density function theory(DFT)*** work reveals that,all solute columns in a same cluster trend to grow along the[0001]Mg direction *** method presented is not only used for the Mg-Y alloy but also other Mg-RE alloys such as Mg-Gd as illustrated in the last part of the paper.

关键词： Mg-RE alloys Kinetic Monte Carlo method DFT calculations Solute clusters

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In-situ confocal microscopy study on dissolution kinetics of calcium aluminate inclusions in CaO-Al_(2)O_(3)-SiO_(2)type steelmaking slags

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Journal of Iron and Steel Research International 2025年第2期32卷 364-375页

作者： Guang Wang Muhammad Nabeel Wangzhong Mu A.B.Phillion Neslihan Dogan Department of Materials Science and Engineering McMaster UniversityHamilton L8S4L7OntarioCanada Department of Materials Science and Engineering KTH Royal Institute of TechnologyStockholm 10044Sweden Engineering Materials Department of Engineering Science and MathematicsLuleå University of TechnologyLuleå 97187Sweden Department of Materials Science and Engineering Delft University of TechnologyDelft 2628CDThe Netherlands

Dissolution kinetics of CaO·2Al_(2)O_(3)(CA_(2))particles in a synthetic CaO-Al_(2)O_(3)-SiO_(2)steelmaking slag system have been investigated using the high-temperature confocal laser scanning *** of temperature(i.e.,1500,1550,and 1600℃)and slag composition on the dissolution time of CA_(2)particles are investigated,along with the time dependency of the projection area of the particle during the dissolution *** is found that the dissolution rate was enhanced by either an increase in temperature or a decrease in slag ***,a higher ratio of CaO/Al_(2)O_(3)(C/A)leads to an increased dissolution rate of CA_(2)particle at 1600℃.Thermodynamic calculations suggested the dissolution product,i.e.,melilite,formed on the surface of the CA_(2)particle during dissolution in slag with a C/A ratio of 3.8 at 1550℃.Scanning electron microscopy equipped with energy dispersive X-ray spectrometry analysis of as-quenched samples confirmed the dissolution path of CA_(2)particles in slags with C/A ratios of 1.8 and 3.8 as well as the melilite formed on the surface of CA_(2)*** formation of this layer during the dissolution process was identified as a hindrance,impeding the dissolution of CA_(2)particle.A valuable reference for designing or/and choosing the composition of top slag for clean steel production is provided,especially using calcium treatment during the secondary refining process.

关键词： In-situ observation Dissolution kinetics Confocal laser scanning microscope Calcium aluminate inclusion Steelmaking slag Clean steel

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Thermal-field boosting continuous white light generation in lanthanide doped Y_(2)SiO_(5)phosphor

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Journal of Rare Earths 2025年第4期43卷 669-675,I0001页

作者： Qiongyao Han Jianhong Wu Yu Hou Bining Tian Xiaofeng Liu Chunli Guo Yue Tian Institute of New Carbon Materials College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan030024China College of Electronic Information and Optical Engineering Taiyuan University of TechnologyTaiyuan030024China College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan030024China School of Materials Science and Engineering Zhejiang UniversityHangzhou310027China

The continuous white light(CWL)covering the visible and near-infrared(NIR)regions can be observed in various absorptive media excited by continuous-wave(CW)*** is valuable to stimulate more efforts in unravelling the involved photophysical processes and exploring its potential applications in diverse ***,we proved that the enhanced thermal-field can boost the CWL *** rare earth(RE)ions(Pr^(3+),Er^(3+)and Yb^(3+))as the photothermally active centers in Y_(2)SiO_(5)phosphor,we reveal that absorbing more excitation energy and isolating the heat conduction can lead to rapid thermal field accumulation inside the material,thereby significantly reducing the excitation threshold and enhancing white light *** results might have important implications for the understanding of thermally enhanced radiation and may facilitate the CWL commercial application in night vision,bioimaging,and non-destructive detection.

关键词： Continuous white light Rare earths Upconversion Thermally enhanced radiation

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Oxidation resistant low-alloyed Ti alloys with good ductility

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Rare Metals 2024年第8期43卷 3921-3936页

作者： Meng Li Zhang-Zhi Shi Jun-Yi Xu Fu-Zhi Dai Xiang-Min Li Zi-Lin Li Lu-Ning Wang Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advance Metals and MaterialsSchool of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijingBeijing 100083China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China

Oxidation resistance enhancement of pure Ti often comes at the cost of reduced ductility,which is frequently the problem through alloying with sole Al,Si,W,Mo and *** overcome the short coming of single element alloying,this paper proposes a multi-element low-alloying strategy to take advantage of synergistic effects and resolve the conflict between oxidation resistance and *** demonstrates that the addition of a small quantity of Ta(0.51wt%)can boost both oxidation resistance and ductility in comparison to pure ***,the combined addition of a small amount(0.54 wt%)of Ta,Nb and Si not only preserves good ductility of pure Ti,but also reduces mass gains to 14%-67%of pure Ti during 100 h oxidation at 650-850℃in *** indicates even better oxidation resistance than that obtained through the use of Ta,Nb,or Nb+Ta *** Ta+Nb+Si alloying creates an oxide layer that is less porous and more resistant to stratification and ***,a 3-μm N-rich layer can form in the Ti substrate beneath the oxide scale,in which phase transformation generates coherent Ti_(2)N with(0001)_(Ti)as the habit plane,with N atoms prefers to diffuse along■than along[0001]_(Ti).The completely transformed Ti_(2)N region or partially transformed Ti+Ti_(2)N region can effectively impede oxygen ***,the multielement low-alloying strategy is promising for enhancing both oxidation resistance and mechanical properties of metallic materials in the future.

关键词： Ti alloys Multi-element Co-alloying Oxidation resistance Mechanical properties

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Heterobimetallic[NiCo]integration in a hydrogenase mimic for boosting light-driven hydrogen evolution in CaTiO_(3)

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Nano Research 2024年第8期17卷 6888-6894页

作者： Kang Li Juanji Hong Ningning Song Zhanjun Guo Minmin Liang Experimental Center of Advanced Materials School of Materials Science&EngineeringBeijing Institute of TechnologyBeijing 10081China

Light-drive hydrogen production using titanium-based perovskite is one sustainable way to reduce current reliance on fossil fuels,but its wide applications are still limited by high electron−hole recombination and sluggish surface ***,the developments for low-cost and highly efficient co-catalysts remain *** by natural[NiFe]-hydrogenase active center structure,a hydrogenase-mimic,NiCo_(2)S_(4) nanozyme was synthesized,and subsequently decorated onto the CaTiO_(3) to catalyze the hydrogen evolution reaction(HER).Among the following test,CaTiO_(3)with a 15%loading of NiCo_(2)S_(4) nanozyme exhibited the highest HER rate of 307.76μmol·g^(–1)·h^(–1),which is 60 times higher than that of the CaTiO_(3) *** results reveal that NiCo_(2)S_(4) not only significantly increased the charge separation efficiency of the photogenerated carriers,but also substantively lowered the HER activation *** studies show that NiCo_(2)S_(4) readily splits H_(2)O by forming the Ni(OH)-Co intermediate and only Ni in the bimetallic center alters the oxidation state during the HER process in a manner analogous to the[NiFe]-*** contrast to the often-expensive synthetic catalysts that rely on rare elements such as ruthenium and platinum,this study shows a promising way to develop the nature-inspired cocatalysts to enhance the photocatalysts’HER performance.

关键词： hydrogen evolution reaction hydrogenase-mimic nanozyme photocatalyst water-splitting

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Earth-abundant Zn-dipyrrin chromophores for efficient CO2 photoreduction

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National science Review 2024年第6期11卷 214-222页

作者： Song Guo Fu-Gui Zeng Xiao-Di Li Kai-Kai Chen Ping Wang Tong-Bu Lu Zhi-Ming Zhang Institute for New Energy Materials and Low Carbon Technologies School of Materials Science& Engineering Tianjin University of Technology

The development of strong sensitizing and Earth-abundant antenna molecules is highly desirable for CO2reduction through artificial photosynthesis. Herein, a library of Zn–dipyrrin complexes（Z-1-Z-6） are rationally designed via precisely controlling their molecular configuration to optimize strong sensitizing Earth-abundant photosensitizers. Upon visible-light excitation, their special geometry enables intramolecular charge transfer to induce a charge-transfer state, which was first demonstrated to accept electrons from electron donors. The resulting long-lived reduced photosensitizer was confirmed to trigger consecutive intermolecular electron transfers for boosting CO2-to-CO conversion. Remarkably, the Earth-abundant catalytic system with Z-6 and Fe-catalyst exhibits outstanding performance with a turnover number of >20 000 and 29.7% quantum yield, representing excellent catalytic performance among the molecular catalytic systems and highly superior to that of noble-metal photosensitizer Ir（ppy）2（bpy）+under similar conditions. Experimental and theoretical investigations comprehensively unveil the structure–activity relationship, opening up a new horizon for the development of Earth-abundant strong sensitizing chromophores for boosting artificial photosynthesis.

关键词： Zn complex photocatalysis CO2 reduction charge transfer photosensitizer

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Taming of trinitromethyl-oxadiazole to access high density and high oxygen balance via a dual modulation strategy

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Defence Technology(防务技术) 2025年第1期43卷 142-149页

作者： Jinya Zhang Teng Fei Jingwei Meng Jinxiong Cai Lei Zhang Siping Pang Chunlin He School of Materials Science&Engineering Beijing Institute of TechnologyBeijing 100081China Experimental Center of Advanced Materials School of Materials Science&EngineeringBeijing Institute of TechnologyBeijing 100081China hongqing Innovation Center Beijing Institute of TechnologyChongqing 401120China

Energetic compounds bearing the trinitromethyl group are garnering broad attraction as potential candidates for a new generation of high energy dense *** this work,an effective dual modulation strategy involving both molecular isomerization and crystal morphology control was employed to design and optimize trinitromethyl-oxadiazole with improved comprehensive *** this dual strategy,3,5-bis(trinitromethyl)-1,2,4-oxadiazole(3)was synthesized,resulting in the formation of two distinct crystal morphologies(needle and sheet)corresponding to two crystal forms(3-a and3-b).Encouragingly,while maintaining ultra-high oxygen balance(21.73%),3 achieves impressive densities(1.97-1.98 g/cm^(3)).To our knowledge,the density of 1.98 g/cm^(3)for 3-a sets a new record among that of nitrogen-rich monocyclic ***,practical crystal morphology prediction was creatively introduced to guide the experimental crystallization conditions of 3,increasing the impact sensitivity and friction sensitivity from 1 J to 80 N(3-a)to 10 J and 240 N(3-b),***,the crystal structural analyses and theoretical calculations were conducted to elucidate the reasons of differences between 3-a and 3-b in density and *** work provides an efficient strategy to enhance performance of trinitromethyl derivatives,broadening the path and expanding the toolbox for energetic materials.

关键词： Energetic materials High oxygen balance High density Dual modulation Trinitromethyl group

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Microstructure and Mechanical Properties of Al_(2)O_(3p)/AZ91 Magnesium Matrix Laminated Material Adjusted by Freezing Temperature

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Acta Metallurgica Sinica(English Letters) 2024年第11期37卷 1819-1829页

作者： Ze-Xin Bai Kun-Kun Deng Ze-Qi Du Kai-Bo Nie Chao Xu Quan-Xin Shi Shanxi Key Laboratory of Advanced Magnesium-based Materials College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan 030024China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

The Al_(2)O_(3)laminated preforms with different layers thickness were prepared by freezing casting in present ***,the Al_(2)O_(3p)/AZ91 magnesium matrix laminated materials were obtained by infiltrating the AZ91 alloy melt into the Al_(2)O_(3)laminated preform based on pressure infiltration ***,the influence of freezing temperature on the microstructure,mechanical properties and fracture behavior of magnesium-based laminates was *** results indicated that with the decrease of freezing temperature,the thickness of Al_(2)O_(3)layers decreases gradually,the number of layers increases obviously,and the interlayers spacing *** with the decrease of interlayers spacing,the size of Mg17Al12 phase precipitated in the AZ91 alloy layers was refined,and the compression strength and strain were both improved *** micro-cracks initiated in Al_(2)O_(3)layers during loading process,while the AZ91 layers could effectively suppress the initiation and propagation of ***,the changing layers structure influenced by the decrease of freezing temperature had significant inhibiting effect on the initiation and propagation of micro-cracks,which endowed the Al_(2)O_(3p)/AZ91 magnesium matrix laminated materials with better strength and ***,the best compression properties of Al_(2)O_(3p)/AZ91 magnesium matrix laminated materials could be obtained at the freezing temperature of−50℃,the compression strength and elastic modulus of which were the 160%and 250%of monolithic AZ91 alloy,respectively.

关键词： Bio-inspired composites Freeze-casting Mechanical properties Metal matrix composites

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Enhanced memristor performance via coupling effect of oxygen vacancy and ferroelectric polarization

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Journal of materials science & Technology 2024年第4期171卷 139-146页

作者： Zhi Yun Yue Zhi Dong Zhang Zhan Jie Wang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China

As a new type of nonvolatile memory,the resistive memristor has broad application prospects in in-formation storage and neural computing based on its excellent resistive switching(RS)*** present,it is still a great challenge to improve both ferroelectric polarization and leakage current to achieve a high RS on/offratio of ferroelectric ***,epitaxial Pb(Zr_(0.40)Ti_(0.60))O_(3)(PZT)thin films with low content Ca doping were deposited on the Nb:SrTiO_(3)substrate to prepare PCZT/NSTO het-erostructures and their RS behaviors were *** research findings show that compared with pure PZT film,the ferroelectric polarization of 1-mol%-Ca-doped PZT film is slightly improved,while the leak-age current is increased by three orders of ***,the RS on/offratio reaches 2.5×10^(5),about three orders of magnitude higher than pure PZT *** theoretical analysis reveals that the RS behavior of PCZT/NSTO heterostructures is controlled by the PCZT/NSTO interfacial barrier and the space charge-limited current *** results demonstrate that the ferroelectricity and electricity of ferroelectric thin films can be improved simultaneously by doping low-content Ca ions to increase the RS performance,which provides a good reference for the development of high-performance ferroelectric memristor devices.

关键词： Ferroelectric memristor Ca-doped PZT Ferroelectric polarization Oxygen vacancies Resistive switching

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Grain-size effect on dislocation source-limited hardening and ductilization in bulk pure Ni

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Journal of materials science & Technology 2023年第23期154卷 9-21页

作者： Kai Hu Jun Yi Bo Huang Gang Wang Institute of Materials School of Materials Science and Engineering Shanghai University Shanghai 200444 China

Dislocation source-limited hardening and ductilization is an effective strategy to obtain superior strength-ductility synergy in some engineering structural metals. Recent works demonstrated that the synergy could be enhanced by grain-size reduction. However, the mechanism of grain-size dependence is still a mystery. In this work, bulk pure Ni produced by electrodeposition and subsequent annealing, with grain sizes ranging from ∼20 nm to ∼20 µm, were methodically investigated to unravel the mechanism of the grain-size effect on dislocation source-limited hardening and ductilization. The high-density nano-twinning in the as-electrodeposited nanograined specimens exhibited better thermodynamic stability than the peers with random high-angle grain boundaries, leading to fine recrystallized grains with low-density dislocations. The low dislocation density enabled extra hardening beyond grain boundary strengthening via yield-point behavior with grain sizes ranging from ∼110 nm to ∼10 µm and extra ductilization over ∼500 nm. This work demonstrated that the prerequisite for dislocation source-limited hardening was that the dislocation density of the specimen should be lower than the size-dependent critical value of ((1.1 × 107 /d ) m^(–2), d is the grain size in unit of the meter) where a transition from forest-dominated hardening to dislocation source-limited hardening could occur. On the other hand, dislocation source-limited ductilization only worked when the grain size was comparable to/larger than the theoretical dislocation mean slip distance. Dislocation source-limited ductilization resulted from more room in grains for accumulation of dislocations and deformation nano-stacking faults enabling the higher work hardening rate. This work offered an altogether new avenue to obtain stronger and more ductile metallic materials through utilizing grain-size dependent dislocation source-limited hardening and ductilization.

关键词： Dislocation source-limited hardening Dislocation source-limited ductilization Grain size Yield point Hall-Petch slope

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