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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

Flow past polygons with an odd number of edges

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Science China(Physics,Mechanics & Astronomy) 2011年第4期54卷 683-689页

作者： tian ZhongWei NIU hongtao wu ZiNiu School of Aerospace Tsinghua University Beijing 100084 China

In tian and wu (2009),the present authors studied the inviscid and viscous flow past polygons with an arbitrary but even number of edges and with one apex pointing to the free *** we extend the results to the flow past polygons with an odd number of edges,and an arbitrary *** features such as the shape of stationary lines,stabilities of vortex pairs,1st critical Reynolds numbers,and flow patterns with separations,similar to or different from the results for even-sided polygons,are identified.

关键词： flow past polygons Schwarz-Christoffel mapping stationary lines and stabilities vortex pair separation

Analytical solutions of three-dimensional contaminant transport in uniform flow field in porous media:A library

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Frontiers of Environmental Science & Engineering 2009年第1期3卷 112-128页

作者： hongtao WANG Huayong wu Department of Environmental Science and Engineering Tsinghua UniversityBeijing 100084China

The purpose of this study is to present a library of analytical solutions for the three-dimensional contaminant transport in uniform flow field in porous media with the first-order decay,linear sorption,and zero-order *** library is constructed using Green's function method(GFM)in combination with available *** library covers a wide range of solutions for various *** aquifer can be vertically finite,semi-infinitive or infinitive,and laterally semi-infinitive or *** geometry of the sources can be of point,line,plane or volumetric body;and the source release can be continuous,instantaneous,or by following a given function over *** forms of the solutions are also proposed.A computer code FlowCAS is developed to calculate the *** results demonstrate the correctness of the presented *** library is widely applicable to solve contaminant transport problems of one-or multiple-dimensions in uniform flow fields.

关键词： solution library contaminant transport analytical solution dispersion and advection porous media type curve Green’s function method(GFM)

Quantification of photosynthetic inorganic carbon utilisation via a bidirectional stable carbon isotope tracer

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Acta Geochimica 2016年第2期35卷 130-147页

作者： hongtao Hang Yanyou wu State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of SciencesGuiyang 550081 China University of Chinese Academy of Sciences Beijing 100049China

The amount of bicarbonate utilised by plants is usually ignored because of limited measurement methods. Accordingly, this study quantified the photosynthetic assimilation of inorganic carbon （COe and HCO3-） by plants. The net photosynthetic COa assimilation （PN）, the photosynthetic assimilation of CO2 and bicarbonate （PN＇）, the proportion of increased leaf area （lEA） and the stable carbon isotope composition （δ13C） of Orychophragmus violaceus （Ov） and Brassica juncea （B j） under three bicarbonate levels （5, 10 and 15 mm NaHCO3） were examined to determine the relationship among PN, PN＇ and fLA. PN＇, not PN, changed synchronously with fLA. Moreover, the proportions of exogenous bicarbonate and total bicarbonate （including exogenous bicarbonate and dissolved CO2-generated bicarbonate） utilised by Ov were 2.27 % and 5.28 % at 5 mm bicarbonate, 7.06 % and 13.28 % at 10 mm bicarbonate, and 8.55 % and 17.31% at 15 mm bicarbonate, respectively. Meanwhile, the propor- tions of exogenous bicarbonate and total bicarbonate uti- lised by Bj were 1.77 % and 3.28 % at 5 mm bicarbonate, 2.11% and 3.10 % at 10 mm bicarbonate, and 2.36 % and 3.09 % at 15 mm bicarbonate, respectively. Therefore, the dissolved CO2-generated bicarbonate and exogenous bicarbonate are important sources of inorganic carbon for plants.

关键词： Karst Bicarbonate - Photosynthesis -Inorganic carbonic utilization Stable carbon isotopecomposition

Influence of Thermal Cycling on the Microstructure and Shear Strength of Sn3.5Ag0.75Cu and Sn63Pb37 Solder Joints on Au/Ni Metallization

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Journal of Materials Science & Technology 2007年第1期23卷 68-72页

作者： hongtao CHEN Chunqing WANG Mingyu LI Dewen tian Micro joining Lab. School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China Department of Materials Science and Engineering Jiamusi University Jiamusi 154007 China Harbin Institute of Technology Shenzhen Graduate School Shenzhen 518055 China

The influence of thermal cycling on the microstructure and joint strength of Sn3.5Ag0.75Cu （SAC） and Sn63Pb37 （SnPb） solder joints was investigated. SAC and SnPb solder balls were soldered on 0.1 and 0.9 μm Au finished metallization, respectively. After 1000 thermal cycles between -40℃ and 125℃, a very thin intermetallic compound （IMC） layer containing Au, Sn, Ni, and Cu formed at the interface between SAC solder joints and underneath metallization with 0.1 μm Au finish, and （Au, Ni, Cu）Sn4 and a very thin AuSn-Ni-Cu IMC layer formed between SAC solder joints and underneath metallization with 0.9 μm Au finish. For SnPb solder joints with 0.1 μm Au finish, a thin （Ni, Cu, Au）3Sn4 IMC layer and a Pb-rich layer formed below and above the （Au, Ni）Sn4 IMC, respectively. Cu diffused through Ni layer and was involved into the IMC formation process. Similar interfacial microstructure was also found for SnPb solder joints with 0.9μm Au finish. The results of shear test show that the shear strength of SAC solder joints is consistently higher than that of SnPb eutectic solder joints during thermal cycling.

关键词： Sn3.5Ag0.75Cu Solder joint Au finish Intermetallic compound

A multiphysical-geochemical coupling model for caprock sealing efficiency in CO_(2) geosequestration

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Deep Underground Science and Engineering 2023年第2期2卷 188-203页

作者： Jianguo Wang Huimin Wang Xiaolin Wang Shengqi Yang hongtao wu Chunfai Leung Jiali tian School of Mechanics and Civil Engineering China University of Mining and TechnologyXuzhouChina State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhouChina College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjingChina School of Engineering University of TasmaniaHobartTasmaniaAustralia Center for Offshore Research and Engineering National University of SingaporeSingaporeSingapore

Precipitation or dissolution due to geochemical reactions has been observed in the caprocks for CO_(2) *** reactions modify the caprock sealing efficiency with self-limiting or ***,the effect of this modification on the caprock sealing efficiency has not been fully investigated through multiphysical-geochemical coupling *** this study,a multiphysical-geochemical coupling model was proposed to analyze caprock sealing *** coupling model considered the full couplings of caprock deformation,two-phase flow,CO_(2) concentration diffusion,geochemical reaction,and CO_(2) *** two-phase flow only occurs in the fracture network and the CO_(2) may partially dissolve into water and diffuse through the concentration *** dissolved CO_(2) has geochemical reactions with some critical minerals,thus altering flow *** CO_(2) in the fracture network diffuses into matrix,causing the matrix *** fully coupling model was validated with a penetration experiment on a cement cube and compared with two other models for CO_(2) storage ***,the effects of geochemical reactions on penetration depth and pore pressure were studied through parametric *** numerical simulations reveal that the coupling of geochemical reactions and matrix diffusion significantly affect the caprock sealing *** reactions occur at a short time after the arrival of CO_(2) concentration and modify the fracture *** CO_(2) diffusion into the matrix requires a much longer time and mainly induces matrix *** effects may produce selfenhancement or self-limiting depending on the flow rate in the fracture network,thus significantly modifying caprock sealing efficiency.

关键词： caprock sealing efficiency CO_(2)diffusion CO_(2)geosequestration geochemical reaction sorption strain

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Exploring the nonlinear piezoresistive effect of 4HSiC and developing MEMS pressure sensors for extreme environments

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Microsystems & Nanoengineering 2023年第2期9卷 59-76页

作者： Chen wu Xudong Fang Qiang Kang Ziyan Fang Junxia wu hongtao He Dong Zhang Libo Zha Bian tian Ryutaro Maedai Zhuangde Jjang State Key Laboratory for Manufacturing Systems Engineering International Joint Laboratory for Micro/Nano Manufacturing and Measurement TechnologiesXian Jiaotong UniversityXian 710049China School of Mechanical Engineering Xian Jiaotong UniversityXi'an 710049China Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai 265503China Xi'an Jiaotong University(Yantai)Research Institute for Intelligent Sensing Technology and System Xi'an Jiaotong UniversityXianChina HeBei Semiconductor Research Institute Shjiazhuang 050051China

Microelectromechanical system(MEMS)pressure sensors based on silicon are widely used and offer the benefits of miniaturization and high ***,they cannot easily withstand high temperatures exceeding 150 ℃ because of intrinsic material ***,we proposed and executed a systematic and full-process study of Sic-based MEMS pressure sensors that operate stably from-50 to 300 ℃.First,to explore the nonlinear piezoresistive effect,the temperature coefficient of resistance(TCR)values of 4H-SiC piezoresistors were obtained from-50 to 500 ℃.A conductivity variation model based on scattering theory was established to reveal the nonlinear variation ***,a piezoresistive pressure sensor based on 4H-SiC was designed and *** sensor shows good output sensitivity(3.38 mVN/MPa),accuracy(0.56%FS)and low temperature coefficient of sensitivity(TCS)(-0.067%FS/℃)in the range of-50 to 300 ℃.In addition,the survivability of the sensor chip in extreme environments was demonstrated by its anti-corrosion capability in H_(2)SO_(4) and NaOH solutions and its radiation tolerance under 5 W ***,the sensor developed in this work has high potential to measure pressure in high-temperature and extreme environments such as are faced in geothermal energy extraction,deep well dilling,aeroengines and gas turbines.

关键词： environments extreme nonlinear

ELECTRONIC SUPPORT FOR KNOWLEDGE CREATION IN A RESEARCH INSTITUTE

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Journal of Systems Science and Systems Engineering 2007年第2期16卷 235-253页

作者： hongtao REN Jing tian Yoshiteru NAKAMORI Andrzej P. WIERZBICKI School of Knowledge Science Japan Advanced Institute of Science and Technology Ishikawa 923-1292 Japan National Institute of Telecommunications (NIT) Szachowa 1 04-894 Warsaw Poland International Institute for Applied Systems Analysis A-2361 Laxenburg Austria

This paper focuses on the question how to build an electronic support environment for knowledge creation in a research institute （JAIST）. In order to assess the importance of diverse conditions of scientific creativity, we performed a survey in JAIST, and extracted useful knowledge from the database of survey results. Following the analysis of the theory of academic processes of knowledge creation and the survey findings in JAIST, a computer-based integrated system is proposed. In the aspect of the system design, we postulate that an electronic support environment for academic creativity can be achieved through a seamless integration with Internet, Application Server, Middle Ware, Database and Data Warehouse. The paper addresses issues of knowledge representation in the Electronic Support System for academic research, testing and evaluation issues and conclusions.

关键词： Electronic support software system knowledge creation

Numerical Analysis of the Nonlinear Interactions Between Lamb Waves and Microcracks in Plate

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Acta Mechanica Solida Sinica 2019年第6期32卷 767-784页

作者： hongtao Lv Jingpin Jiao Bin wu Cunfu He Department of Mechanical Engineering and Applied Electronics Technology Beijing University of TechnologyBeijing 100124China

In this paper,three-dimensional finite-element modeling is conducted to investigate the nonlinear interactions between Lamb waves and *** simulation research focuses on the influence of microcrack orientation on the propagation direction of generated sum-frequency Lamb *** simulation results show that the resonant conditions based on classical nonlinear theory are valid for such interactions,leading to the generation of transmitted and reflected sum-frequency SO waves(SFSWs).Moreover,the propagation directions of these two SFSWs exhibit different trends with respect to the orientations of *** transmitted SFSW can be used to detect microcracks,whereas the reflected one can be used to measure their orientations.

关键词： Nonlinear ultrasonic Lamb wave mixing Resonant condition Microcrack Finiteelement method