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Review of precipitation strengthening in ultrahigh-strength martensitic steel

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 256-269页

作者： Zhihao tian Chunlei Shang Chaolei Zhang Xiaoye Zhou Honghui Wu Shuize Wang Guilin Wu Junheng Gao Jiaming Zhu Xinping Mao Institute for Carbon Neutrality University of Science and Technology BeijingBeijing 100083China Institute of Steel Sustainable Technology Liaoning Academy of MaterialsShenyang 110004China Department of Materials Science and Engineering Shenzhen MSU-BIT UniversityShenzhen 518172China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China School of Civil Engineering Shandong UniversityJinan 250061China

Martensite is an important microstructure in ultrahigh-strength steels,and enhancing the strength of martensitic steels often involves the introduction of precipitated phases within the martensitic *** considerable research efforts devoted to this area,a systematic summary of these advancements is *** review focuses on the precipitates prevalent in ultrahigh-strength martensitic steel,primarily carbides(e.g.,MC,M_(2)C,and M_(3)C)and intermetallic compounds(e.g.,Ni Al,Ni_(3)X,and Fe_(2)Mo).The precipitation-strengthening effect of these precipitates on ultrahigh-strength martensitic steel is discussed from the aspects of heat treatment processes,microstructure of precipitate-strengthened martensite matrix,and mechanical ***,a perspective on the development of precipitation-strengthened martensitic steel is presented to contribute to the advancement of ultrahigh-strength martensitic *** review highlights significant findings,ongoing challenges,and opportunities in the development of ultrahigh-strength martensitic steel.

关键词： ultrahigh-strength martensitic steel precipitation strengthening mechanical property carbide intermetallic compound

The First Total Synthesis of 16-Hydroxygeranylgeraniol

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Chinese Chemical Letters 2003年第3期14卷 249-250页

作者： Li Zeng PENG tian sheng MEI 等 NationalLaboratoryofAppliedOrganicChemistry InstituteofOrganicChemistryLanzhouUniversityLanzhou730000 NationalLaboratoryofAppliedOrganicChemistry InstituteofOrganicChemistryLanzh

Facile synthesis of 16-hydroxygeranylgeranio 1, a naturally occurring alicyclic diterpene, by alkylation reaction of allylic iodide 3 with phenyl sulfone 4, is described.

关键词： Total synthesis 16-hydroxygeranylgeraniol diterpene.

Preparation of mesoporous silica microspheres with multi-hollow cores and their application in sustained drug release

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Particuology 2010年第5期8卷 447-452页

作者： Chen Zhang tian Hou Jianfeng Chen Lixiong wen Key Lab for Nanomaterials Ministry of Education Beijing University of Chemical Technology Beijing 100029 China Research Center of the Ministry of Education for High Gravity Engineering & Technology Beijing University of Chemical Technology Beijing 100029 China

Mesoporous silica microspheres with multi-hollow cores （MSMMCs） were prepared by an O1/W/O2 double emulsion technique. When tetraethyl orthosilicate （TEOS） was hydrolyzed in the O1/W/O2 double emulsion with P123 （a triblock copolymer with a formula of HO（CH2CH20）20（CH2CH（CH3）O）70（CH2CH2O）20H） dissolved in the aqueous phase, the internal oil droplets would serve as templates for the empty hollow cores, P123 function as templates for the mesopores in the shell, and the aqueous phase act as space-limiting micro-reactors for the hydrolysis process, thus forming MSMMCs with controllable size and hollow cores. After further modification by a high-temperature aging process, the prepared MSMMCs had a diameter of 2-10 μm, with macromulti-hollow cores with a size of 100-1000 nm, mesopores in the shell with a size of 3.8-4.4 nm, and a surface area of 383-735 m2/g. In addition, MSMMCs were used as carriers to load avermectin through an immersing and evaporating process, and the loaded avermectin showed a well sustained release behavior from the MSMMCs matrix. This study demonstrated a promising and simple method for preparing silica micro-particles with porous multi-hollow core structure for sustained release applications.

关键词： SilicaPreparationHollow structureSustained release

The simultaneous removal of ammonium and manganese from surface water by MeO_x:Side effect of ammonium presence on manganese removal

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Journal of Environmental Sciences 2019年第3期31卷 346-353页

作者： Xuan tian Ruifeng Zhang Tinglin Huang Gang wen Key Laboratory of Northwest Water Resource Environment and Ecology MOE Xi'an University of Architecture and Technology Shaanxi Key Laboratory of Environmental Engineering Xi'an University of Architecture and Technology

Manganese and ammonium pollution in surface water sources has become a serious *** this study, a pilot-scale filtration system was used to investigate the effect of ammonium on manganese removal during the simultaneous removal of ammonium and manganese from surface water using a manganese co-oxide filter film(MeO_x ). The results showed that the manganese removal efficiency of MeO_x in the absence of ammonium was high and stable, and the removal efficiency could reach 70% even at 5.5 °C. When the influent ammonium concentration was lower than 0.7 mg/L, ammonium and manganese could be removed simultaneously. However, at an ammonium concentration of 1.5 mg/L, the manganese removal efficiency of the filter gradually decreased with time(from 96% to 46.20%). Nevertheless, there was no impact of manganese on ammonium removal. The mechanism by which ammonium negatively affected manganese removal was investigated, demonstrating that ammonium affected manganese removal mainly through two possible mechanisms. On one hand, the decreased p H caused by ammonium oxidation was unfavorable for the oxidation of manganese by MeO_x ; on the other hand, the presence of ammonium slowed the growth of new MeO_x and retarded the increase in the specific surface area of the Me Ox-coated sand, and induced changes in the morphology and crystal structure of Me Ox. Consequently, the manganese removal efficiency of the filter decreased when ammonium was present in the inlet water.

关键词： Surface water Manganese Ammonium MeO_x Side effect

Effect of solution cooling rate on the γ′ precipitation behaviors of a Ni-base P/M superalloy

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Journal of University of Science and Technology Beijing 2008年第6期15卷 729-734页

作者： Gaofeng tian Chengchang Jia Ying wen Benfu Hu School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

The effect of cooling rate on the cooling γ′ precipitation behaviors was investigated in a Ni-base powder/metallurgy （P/M） superalloy （FGH4096）. The empirical equations were established between the cooling rate and the average sizes of secondary and tertiary γ′ precipitates within grains and tertiary γ′ precipitates at grain boundaries, as well as the apparent width of grain boundaries. The results show that the average sizes of secondary or tertiary γ′ precipitates are inversely correlated with the cooling rate. The shape of secondary γ′ precipitates within grains changes from butterfly-like to spherical with the increase of cooling rate, but all the tertiaryγ′ precipitates formed are spherical in shape. It is also found that tertiary γ′ may be precipitated in the latter part of the cooling cycle only if the cooling rate is not faster than 4.3℃/s, and the apparent width of grain boundaries decreases linearly with the increase of cooling rate.

关键词： powder metallurgy Ni-base superalloy precipitates cooling rate

Time-series analysis of the characteristic pressure fluctuations in a conical fluidized bed with negative pressure

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Chinese Journal of Chemical Engineering 2021年第4期34卷 87-99页

作者： sheng Fang Yanding Wei Lei Fu Geng tian Haibin Qu The State Key Laboratory of Fluid Power and Mechatronic Systems College of Mechanical EngineeringZhejiang UniversityHangzhou 310027China Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province College of Mechanical EngineeringZhejiang UniversityHangzhou 310027China College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310023China Pharmaceutical Informatics Institute College of Pharmaceutical SciencesZhejiang UniversityHangzhou 310058China

The negative pressure conical fluidized bed is widely used in the pharmaceutical *** this study,experiments based on the negative pressure conical fluidized bed are carried out by changing the material mass and particle *** pressure fluctuation signals are analyzed by the time and the frequency domain methods.A method for absolutely characterizing the degree of the energy concentration at the main frequency is proposed,where the calculation is to divide the original power spectrum by the average signal power.A phenomenon where the gas velocity curve temporarily stops growing is observed when the material mass is light,and the particle size is *** standard deviation and kurtosis both rapidly change at the minimum fluidization velocity and thus can be used to determine the flow regime,and the variation rule of the kurtosis is independent of both the material mass and particle *** the initial fluidization stage,the dominant pressure signal comes from the material movement;with the increase in the gas velocity,the power of a 2.5 Hz signal continues to increase.A method of dividing the main frequency by the average cycle frequency can conveniently determine the fluidized state,and a novel concept called stable fluidized zone proposed in this paper can be *** the gas velocity within the stable fluidized zone ensures that the fluidized bed consistently remains in a stable fluidized state.

关键词： Conical fluidized bed Negative pressure Pressure fluctuation Time-series analysis Characteristic value Fluidized state

High-Entropy Spinel Oxide Nanofibers as Catalytic Sulfur Hosts Promise the High Gravimetric and Volumetric Capacities for Lithium–Sulfur Batteries

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Energy & Environmental Materials 2022年第2期5卷 645-654页

作者： Liyuan tian Ze Zhang sheng Liu Guoran Li Xueping Gao Institute of New Energy Material Chemistry School of Materials Science and EngineeringRenewable Energy Conversion and Storage CenterNankai UniversityTianjin 300350China

The exploration of new catalytic hosts is highly important to tackle the sluggish electrochemical kinetics of sulfur redox for achieving high energy density of lithium–sulfur ***,for the first time,we present high-entropy oxide(HEO,(Mg_(0.2)Mn_(0.2)Ni_(0.2)Co_(0.2)Zn_(0.2))Fe_(2)O_(4))nanofibers as catalytic host of *** HEO nanofibers show a synergistic effect among multiple metal cations in spinel structure that enables strong chemical confinement of soluble polysulfides and fast kinetics for polysulfide ***,the S/HEO composite displays the high gravimetric capacity of 1368.7 mAh g^(−1) at 0.1 C rate,excellent rate capability with the discharge capacity of 632.1 mAh g^(−1) at 5 C rate,and desirable cycle ***,the S/HEO composite shows desirable sulfur utilization and good cycle stability under a harsh operating condition of high sulfur loading(4.6 mg cm^(−2))or low electrolyte/sulfur ratio(5μL mg^(−1)).More impressively,the high volumetric capacity of 2627.9 mAh cm^(−3) is achieved simultaneously for the S/HEO composite due to the high tap density of 1.92 g cm^(−3),nearly 2.5 times of the conventional sulfur/carbon ***,based on high-entropy oxide materials,this work affords a fresh concept of elevating the gravimetric/volumetric capacities of sulfur cathodes for lithium–sulfur batteries.

关键词： catalytic host high-entropy oxide lithium-sulfur battery polysulfide conversion spinel oxide nanofibers

Atomic Force Microscopy of Surface Reconstructed SrTiO3 Vicinal Substrates for Epitaxial Growth of YBa_(2)Cu_(3)O_(7-δ) Thin Films

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Chinese Physics Letters 1999年第11期16卷 853-855页

作者： HU wen-fei LI Lin WANG tian-sheng LIU Wei TAO Hong-jie tian Yong-jun CHEN Ying-fei National Laboratory for Superconductivity Chinese Academy of SciencesBeijing 100080 Institute of Physics Chinese Academy of SciencesBeijing 100080 Department of Material Science Yanshan UniversityQinhuangdao 066004

SrTiO_(3)(001) vicinal substrates of miscut 1°, 3°, and 6° toward the (001) plane were annealed at 800-1000°C in pure flowing O_(2) for 6h and examined by atomic force microscopy. The high temperature annealed vicinal SiTiO_(3)(001) displayed arrays of straight steps and smooth terraces. The step heights vary from about 2 to 6 unit cell depending on the annealing temperatures. At 1000°C, step bunching becomes obvious. The height steps of 1 unit cell are difficult to be observed by our atomic force microscopy. The YBa2Cu3O7-δ thin film grows epitaxially on the step-terrace surface with c-axis orientation by magnetron sputtering in the two-dimensional island mode. Prospect of step-flow growth is being discussed.

关键词： steps straight island

Microstructure and phase composition of hypoeutectic Te–Bi alloy as evaporation source for photoelectric cathode

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International Journal of Minerals,Metallurgy and Materials 2018年第5期25卷 584-590页

作者： Bao-guang Wang wen-hui Yang Hong-ye Gao wen-huai tian School of Materials Science and Engineering University of Science and Technology Beijing Faculty of Engineering Sciences Kyushu University

A hypoeutectic 60Te–40Bi alloy in mass percent was designed as a tellurium atom evaporation source instead of pure tellurium for an ultraviolet detection *** alloy was prepared by slow solidification at about 10^(-2) K·s^(-1).The microstructure,crystal structure,chemical composition,and crystallographic orientation of each phase in the as-prepared alloy were investigated by optical microscopy,scanning electron microscopy,X-ray diffraction,electron backscatter diffraction,and transmission electron *** experimental results suggest that the as-prepared 60Te–40Bi alloy consists of primary Bi_2Te_3 and eutectic Bi_2Te_3/Te *** primary Bi_2Te_3 phase has the characteristics of faceted *** eutectic Bi_2Te_3 phase is encased by the eutectic Te phase in the eutectic *** purity of the eutectic Te phase reaches 100wt%owing to the slow *** the eutectic phases,the crystallographic orientation relationship between Bi_2Te_3 and Te is confirmed as[0001]_(Bi2 Te3)//[1213]_Te and the direction of Te phase parallel to[1120]_(Bi2 Te3)is deviated by 18°from N(2111)_Te.

关键词： Te–Bi alloy microstructure orientation misfit