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New Insights into the Aging Embrittlement Mechanism of 30Cr2Ni4MoV Steel Containing Si and Mn

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Acta Metallurgica Sinica(English Letters) 2024年第12期37卷 2163-2169页

作者： Yongfeng Zheng Xiaofeng Hu Haichang Jiang lijian Rong CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China

The aging embrittlement of 30Cr2Ni4MoV steel during service at high temperature has been attributed to the segregation of Si and Mn at grain boundary(GB).We report an alternative mechanism of aging embrittlement of 30Cr2Ni4MoV *** atom probe tomography,it is found that the quenched and tempered(QT)30Cr2Ni4MoV steel has already contained obvious Si and Mn segregations at GB,which means that the Si and Mn segregations at GB are not sufficient to induce aging *** is discovered for the first time in aged 30Cr2Ni4MoV there newly precipitate many G-phases along GB,and Si and Mn segregations at GB of QT30Cr2Ni4MoV steel are the main reason for the precipitation of *** hard and brittle G-phase helps to promote crack initiation during impact ***,the cracks can rapidly propagate along GB due to the distribution of G-phase and the segregation of Si and Mn along the GB,which leads to intergranular cracking and low impact energy as for aged 30Cr2Ni4MoV steel.

关键词： 30Cr2Ni4MoV steel Aging embrittlement Si and Mn Grain boundary segregation G-phase

Effect of Cooling Rate on Microstructure and Effective Grain Size for a Ni–Cr–Mo–B High-Strength Steel

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Acta Metallurgica Sinica(English Letters) 2022年第11期35卷 1862-1872页

作者： Shouqing Zhang Xiaofeng Hu Haichang Jiang lijian Rong CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

The effect of cooling rate on microstructure and effective grain size(EGS)of a Ni-Cr-Mo-B high-strength steel has been studied by dilatometer,field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM)and electron backscattered diffraction(EBSD).The results show that the microstructure of the Ni-Cr-Mo-B steel is dependent on cooling rate in the following sequence:lath martensite(LM),mixed LM and lath bainite(LB),mixed LB and granular bainite(GB)and *** critical cooling rates for appearance of LB and GB are about 10℃/s and 0.5℃/s,*** LM(>10℃/s)consists of few blocky regions with a width of several *** with the lath regions,the blocky regions in LM form at higher actual transformation temperatures during *** blocky region area percentage in LM keeps almost constant about 8%at different cooling rates(>10℃/s)due to similar martensite transformation starting temperature(M_(s)).The LB percentage in mixed LM/LB increases gradually with decreasing cooling rate(10-0.5℃/s).The EBSD results show that different microstructures have different *** mixed LM/LB exhibits the smallest EGS due to the separation of the prior austenite grains by the pre-formed LB and the refinement of the ***,the mixed LM/LB at different cooling rates(10-0.5℃/s)exhibits almost the same EGS because the LB and LM in the mixed LM/LB have a similar high-angle grain boundary density and similar *** the blocky regions contain few high-angle grain boundaries and have similar area percentages in the LM,the LM at different cooling rates(>10℃/s)exhibits almost the same *** ferrite in GB exhibits as a whole with few high-angle grain boundaries;thus,the mixed LB/GB exhibits the largest EGS.

关键词： Ni–Cr–Mo–B steel Cooling rate Microstructural characterization Effective grain size(EGS)

MAPK signaling in inflammation-associated cancer development

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Protein & Cell 2010年第3期1卷 218-226页

作者： Pengyu Huang Jiahuai Han lijian Hui Laboratory of Molecular Cell Biology Institute of Biochemistry and Cell BiologyShanghai Institutes for Biological SciencesChinese Academy of SciencesShanghai 200031China Key Laboratory of the Ministry of Education for Cell Biology and Tumor Cell Engineering School of Life SciencesXiamen UniversityXiamen 361005China

Mitogen-activated protein(MAP)kinases comprise a family of protein-serine/threonine kinases,which are highly conserved in protein structures from unicellular eukaryotic organisms to multicellular organisms,including *** kinases,including ERKs,JNKs and p38s,are regulated by a phosphorelay cascade,with a prototype of three protein kinases that sequentially phosphorylate one *** transduce extracellular signals into a variety of cellular processes,such as cell proliferation,survival,death,and *** with their essential cellular functions,MAPKs have been shown to play critical roles in embryonic development,adult tissue homeostasis and various *** this review,we discuss recent findings that reveal the profound impact of these pathways on chronic inflammation and,particularly,inflammation-associated cancer development.

关键词： inflammation cancer homeostasis

Effect of Cu content on microstructure and properties of Fe-16Cr-2.5Mo damping alloy

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Journal of Materials Science & Technology 2018年第5期34卷 774-781页

作者： Xiaofeng Hu Yubin Du Desheng Yan lijian Rong CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China

Five Fe-16 Cr-2.5 Mo damping alloys with different Cu contents（0%,0.25%,0.5%,1.0% and 2.0%） were *** microstructure was observed by scanning transmission electron microscopy（STEM） and the damping behavior was measured by using a dynamic mechanical analyzer（DMA）.The results show that the grain size of experimental alloy with（0.25–1.0%） Cu was refined compared with the 0 Cu *** Cu element is fully dissolved in the matrix and there are no Cu precipitates and carbides *** the internal stress increases because of Cu addition,the damping capacity of the 0.5 Cu and1.0 Cu alloys has been significantly *** reason of damping improvement is that the magnetic domain structure is strongly ***,the strength was improved gradually due to the Cu solid solution strengthening and grain *** the 2.0 Cu alloy,lots of Cu-riched particles appeared in the *** Cu precipitates with 10–15 nm in size are spherical and homogeneously distributed,which strongly induce strength improvement through precipitation *** the contrary,the elongation and impact energy of the 2.0 Cu alloy decrease *** addition,lots of Cu precipitates will significantly decrease the damping capacity by hindering the mobility of domain walls.

关键词： Fe-16Cr-2.5Mo alloy Cu Damping capacity Strength Precipitation

Experimental Investigation on the Effect of Mainstream Turbulence on Full Coverage Film Cooling Effectiveness for a Turbine Guide Vane

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Journal of Thermal Science 2019年第1期28卷 145-157页

作者： FU Zhongyi ZHU Huiren CHENG lijian JIANG Ru School of Power and Energy Northwestern Polytechnical University

Experiments have been performed to investigate the effect of mainstream turbulence on the three-dimensional distribution of the full coverage film cooling effectiveness for two enlarged actual twisted vanes with cylindrical or shaped holes. The film cooling effectiveness was measured by transient liquid crystal technique at mainstream turbulence intensities of 2%, 9% and 15%. The mass flow rate ratios range from 5.5% to 12.5%. There are 3, 8 and 7 rows of film holes on the suction side, leading edge and pressure side, respectively. Results show that for the cylindrical hole vane the high mainstream turbulence intensity decreases the film cooling effectiveness in the top region and down region of pressure side in the low mass flow rate ratio of 5.5%, while the effect is opposite in the high mass flow rate ratio of 12.5%. The film cooling effectiveness in the middle region of pressure side decreases obviously with the increase of the turbulence at the low mass flow rate ratio of 5.5%, while the influence of increasing turbulence weakens gradually with the increase of mass flow rate ratio. Moreover, the high mainstream turbulence improves the film cooling effectiveness in the further downstream of the holes on suction side at the high mass flow rate ratio of 12.5%. For the shaped hole vane, the increase of mainstream turbulence decreases the film cooling effectiveness at all mass flow rate ratios. This study reveals the influence rule of the mainstream turbulence on the film cooling effectiveness in the different regions of the three-dimensional vane surface. The results would guide the designs of engineering heat transfer with application in gas turbine blade/vane cooling.

关键词： film cooling effectiveness turbulence intensity mass flow rate ratio turbine guide vane

Effect of oxygen precipitates in solar grade silicon on minority carrier lifetime and efficiency of solar cells

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Rare Metals 2006年第z1期25卷 141-145页

作者： SUN Haizhi LIU Caichi HAO Qiuyan WANG lijian Institute of Information Functional Material Hebei University of Technology Tianjin 300130 China Institute of Information Functional Material Hebei University of Technology Tianjin 300130 China Institute of Information Functional Material Hebei University of Technology Tianjin 300130 China Institute of Information Functional Material Hebei University of Technology Tianjin 300130 China

The effect of oxygen precipitates on minority carrier lifetime and performance of solar cell was studied by means of Fourier Transform Infrared Spectroscopy (FTIR), quasi-steady state photoconductance (QSSPCD), optical microscope, spectrum response and solar cell efficiency test. The minority carrier lifetime and performance of solar cell reduced depend on oxygen precipitates. A few of oxygen precipitates have formed after single-step annealing; and they do not impact the efficiency dramatically. Pre-annealing at 650 ℃ for 4 h enhances the oxygen precipitation when it is subjected to middle temperature annealing. The solar cells performance decayed sharply. Especially annealing at 950 ℃ for 3 h, the Vos and Isc of cells decrease 12% and 25% respectively. Few oxygen precipitates have formed in silicon after high temperature annealing at about 1050 ℃ whether pre-annealing is used or not, and the performance of cells is not be affected.

关键词： silicon oxygen precipitate solar cell annealing

Role ofδ-ferrite in fatigue crack growth of AISI 316 austenitic stainless steel

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Journal of Materials Science & Technology 2022年第19期114卷 7-15页

作者： Qiyu Wang Shenghu Chen Xinliang Lv Haichang Jiang lijian Rong CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

FF sample(nearly free ofδ-ferrite)and CF sample(containing∼4%δ-ferrite)were prepared from the AISI 316 austenitic stainless steel plate to elucidate the role ofδ-ferrite in the fatigue crack growth under the solution treated and accelerated aged *** is found that the fatigue crack growth resistance of the CF sample is higher than the FF sample under the solution treated ***,a significant deterioration of the fatigue crack growth resistance is observed in the CF sample while little variation is found in the FF sample after accelerated aging treatment at 750°C for 10 *** the solution treated condition,deflected crack growth path is present when the main crack encounters theδ-ferrite in the CF sample due to the differences in the fatigue responses between austenite andδ-*** measured growth rate of the deflected crack is significantly slower than that of the flat crack of the same *** the accelerated aging treatment,microcracks are produced at the M_(23)C_(6)/δinterface due to the strain incompatibility between M_(23)C_(6) and retainedδ-ferrite when the decomposedδ-ferrite is subject to plastic deformation in the crack tip plastic *** preexisting microcracks in the front of crack tip provide a viable path for crack propagation,resulting in the relatively flat crack path.

关键词： Austenitic stainless steel δ-ferrite Accelerated aging Fatigue crack growth Crack deflection

Temperature‐dependent adaptive conductivity coating for surface charge release and electric field control under electro‐thermal coupling field

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High Voltage 2023年第5期8卷 1082-1092页

作者： Jianyi Xue Zhu Zhang Binbin Li Yushun Zhao lijian Ding School of Electrical Engineering and Automation Hefei University of TechnologyHefeiChina Electric Power Research Institute of State Grid Anhui Electric Power Co. Ltd.HefeiChina

Surface charge accumulation is the potential criminal for surface insulation failure on spacers under direct current(DC)*** existence of thermal gradient posing the difficulty of surface charge *** study proposes a temperature‐dependent adaptive conductivity coating technique for surppressing surface charge accumulation under electro‐thermal coupling field.A two‐dimensional axis‐symmetrical simulation model regrading surface charge computation is *** effects of thermal gradients and coating conductivity on surface charge and electric field distribution are *** results show that the thermal gradient increases the bulk conductive current,therefore aggravating surface charge *** effects of the coating condcutivity on surface charge and electric field contains three *** lower coating conductivity leads to aggravated homo‐polarity charge *** increasing the coating conductivity,the surface charge and electric field are significantly suppressed at the obtained optimal conductivity,where the bulk and surface conductive current reach a balance *** increasing the coating conductivity results in aggravated hetero‐polarity ***,the increase of thermal gradient to an appropriate extent contributes to the further suppression of surface charge on coated *** is hoped that this study could provide some references for designing highly reliable DC GIL under electro‐thermal coupling field.

关键词： coating charge conductivity

Focusing Solar Spectrum by Anthracene Molecules

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Wuhan University Journal of Natural Sciences 2018年第5期23卷 412-417页

作者： CAO Ting LIU lijian College of Chemistry and Molecular Sciences Wuhan University

Conventionally, each fluorophore is only clarified with the wavelength of incident beam shorter（down-conversion） or longer（up-conversion） than that of emission light. However, three anthracenes presented in this paper are the wavelength-focused（WF） molecules which can shift the portions of shorter and longer wavelengths of incident light into an identical wavelength in between. UV（ultraviolet） and NIR（near infrared） portions of Xenon light-simulated solar spectrum are focused into visible light with maximum wavelengths ranging from 415 to 471 nm through the two-way photoluminescence of the three anthracenes（anthracene（AN）, fluoranthene（FLA） and 9, 10-diphenylanthracene（DPA））. At the same time, the intensity of the visible light is two times as that of excitation light. Besides, DPA dissolved in different solvents shows excellent fluorescence features. The results present great potential for applications in enhancing the intensity of solar spectrum at visible region and utilizing more portions of sunlight with solar cell.

关键词： focusing solar spectrum two-way conversion an-thracene