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Journal of Iron and Steel Research(International) 2023年第3期30卷 537-547页

作者： Min Qi Hong-yan Wu Ying Dong lin-xiu du State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina

In order to determine the safe region of 42CrMo4 steel during hot working and obtain excellent workability,the hot deformation behavior at the temperatures of 850-1150℃and the strain rates of 0.01-10 s^(-1)was investigated through single-pass compression test of thermo-simulation.Through observing and analyzing the true stress-strain curves,the conclusion may be drawn that the flow stress value increases with the decrease in deformation temperature and the increase in strain rate.Raising temperature and reducing strain rate are conductive to dynamic recrystallization(DRX)nucleating and growing,but adiabatic heating caused by higher strain rate can also promote it.Since the Zener-Hollomon(Z)value and dynamic recrystallized grain size(D_(DRX))have completely opposite trends with deformation condition parameters,the expression of Z value and DDRX can be determined as:D_(DRx)=15,567.645Z^(-02174).The processing map and instability map constructed at a strain of 0.9 show that the suitable window for hot working with a true strain of 0.9 is in the temperature range of 970-1150℃and strain rate range of 0.01-0.25 s^(-1),as well as at the temperature of 1150℃ and strain rate range of 0.25-10 s^(-1).The instability phenomenon appears in the process interval of 850-1096℃ and 0.22-10 s^(-1).

关键词： Hot deformation behavior Dynamic recrystallization Microstructure evolution Constitutive relationship Processing map

Hydrogen trapping and electrochemical corrosion behavior of V–N microalloyed X80 pipeline steels consisting of acicular ferrite and polygonal ferrite

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Journal of Iron and Steel Research(International) 2022年第10期29卷 1683-1693页

作者： Ming-ming Wang xiu-hua Gao Li-ying Song Cheng-lin Zhu lin-xiu du Raja Devesh Kumar Misra State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819LiaoningChina Laboratory for Excellence in Advanced Steel Research Department of MetallurgicalMaterials and Biomedical EngineeringUniversity of Texas at El PasoEl PasoTX79968USA

Hydrogen trapping behavior of V–N microalloyed X80 pipeline steels was studied by means of hydrogen permeation and hydrogen induced cracking(HIC)tests.In addition,the electrochemical performance of the steels in 3.5 wt.%NaCl solution was investigated.Results indicated that the microstructure of experimental steels mainly consisted of acicular ferrite and polygonal ferrite(PF).When the fraction of PF was 9.1%and 30.4%,hydrogen effective diffusion coefficient was 1.624×10^(−6) and 3.121×10^(−6) cm^(2)/s,respectively.The pipeline steels were not susceptible to HIC.Numerous potential hydrogen traps distributed in homogeneous dispersion were conducive to high HIC resistance.With increasing the fraction of PF from 9.1%to 30.4%,the corrosion current density increased from 5.39×10^(−6) to 9.49×10^(−6) A cm^(−2),the corrosion potential decreased from−0.48 to−0.57 V,and the charge transfer resistance decreased from 2301 to 2068Ωcm^(2),respectively.Increased fraction of PF was disadvantageous for corrosion resistance because of galvanic corrosion.

关键词： Pipeline steel V-N microalloying Hydrogen induced cracking susceptibility Hydrogen permeation Electrochemical corrosion

Erosion corrosion of low-alloy wear-resistant steels in alkaline slurry

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Journal of Iron and Steel Research(International) 2017年第10期24卷 1065-1072页

作者： Feng-ming Song lin-xiu du State Key Laboratory of Rolling Technology and Automation Northeastern UniversityShenyang 110004LiaoningChina

Erosion corrosion causes significant problems in various industrial environments through a synergistic effect which results in much greater weight loss than the sum of the weight losses in the individual processes.The erosion-corrosion behavior of three low-alloy steels was investigated in a simulated concrete slurry using the rotation method.The key influencing factors and mechanism of material degradation were analyzed.The experimental results indicate that the weight loss increases with the linear velocity according to a nearly exponential relationship（W =KV^n）,where nis 1.40-2.14.This weight loss is mainly caused by erosion in the alkaline slurry,and steels with higher tensile strengths show higher erosion-corrosion resistance.The formation of many platelets and ring cracks and their removal from the sample surface during erosion corrosion in the slurry are thought to constitute the mechanism responsible for this weight loss.These platelets and ring cracks are formed by solid particles striking the sample surface.Craters are initially produced and subsequently disappear as they grow and come in contact with each other.Fewer craters were observed on the surfaces of samples that exhibited higher weight loss.The surface of the material became work-hardened because of the effect of the particles striking and scratching,and a deformed layer was produced on the surface for steels of lower strengths,leading to deeper and more abundant gouges.

关键词： Erosion Corrosion Slurry Synergy Steel

Influence of Vanadium Content on Bainitic Transformation of a Low-Carbon Boron Steel during Continuous Cooling

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Acta Metallurgica Sinica(English Letters) 2015年第6期28卷 692-698页

作者： Kwang-Su Kim lin-xiu du Cai-Ru Gao State Key Laboratory of Rolling and Automation Northeastern University Department of Materials Kim Chaek University of Technology

The phase transformation behaviors during continuous cooling of low-carbon boron steels with different vanadium contents were studied by means of dilatometric measurement and microstructure observation. The bainite transformation behavior is not noticeably altered when the vanadium content is 0.042 and 0.086 wt%, and these steels exhibit full bainitic microstructure even at a cooling rate of 5 ℃/s. When vanadium content is increased to 0.18 wt%, ferrite is still present in the microstructure even at a cooling rate of 40 ℃/s. Vickers hardness of the steels with 0.042 and 0.086 wt% V is remarkably higher than that of the steel with 0.18 wt% V at a cooling rate higher than 10 ℃/s, and the difference is increased with the increase in cooling rate. Moreover, the amount of coarse vanadium precipitates formed in austenite is increased with the increase in vanadium content. The optimum content of vanadium to obtain bainitic microstructure is 0.086 wt% in this experimental low-carbon boron steels.

关键词： Microalloyed steel Vanadium Bainitic transformation Boron Microstructure

Corrosion Behavior of Low-Alloy Pipeline Steel with 1% Cr Under CO_2 Condition

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Acta Metallurgica Sinica(English Letters) 2015年第6期28卷 739-747页

作者： Zhen-Guang Liu xiu-Hua Gao Chi Yu lin-xiu du Jian-Ping Li Ping-Ju Hao The State Key Lab of Rolling and Automation Northeastern University School of Resource and Material Northeastern University at Qinhuangdao Mechanical and Electrical Engineering Shijiazhuang Vocational College for Scientific and Technical Engineering

Carbon dioxide corrosion behavior of low-alloy pipeline steel with 1% Cr exposed to CO2-saturated solution was investigated by immersion experiment. SEM, EDX, TEM, EPMA and XRD were utilized to investigate the microstructure, corrosion morphologies, corrosion phases and elements distribution of corrosion scale. The results demon strate that the microstructure of tested steel consists of ferrite and carbides. during the corrosion process, ferrite dissolves preferentially, leaving carbide particles behind. The residual carbide particles may promote the nucleation of FeCO3 crystal. The phase comprising of the inner layer is Cr compound, and the one of the outer layer is FeCO3. The formation process of corrosion scale can be illustrated as follows： Firstly, a thin scale consisting of thin inner layer and outer layer is formed, which represents poor corrosion resistance; then, the inner layer changes little, once it has been formed, and the outer layer becomes thick and compact, which demonstrates that a fine corrosion resistance is obtained. The chemical elements of chromium and molybdenum accumulate in the inner layer of corrosion scale. The corrosion behavior of low- alloy steel based on microstructure and morphology characterization is also discussed.

关键词： Carbon dioxide Low-alloy steel Corrosion behavior Microstructure

Structure-property relationships in heat-affected zone of gas-shielded arc-welded V-N microalloyed steel

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Journal of Iron and Steel Research(International) 2018年第12期25卷 1244-1254页

作者： Jun Hu lin-xiu du Bin Zhang Xiang-yu Qi xiu-hua Gao R.D.K.Misra The State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina Laboratory for Excellence in Advanced Steel Research Department of MetallurgicalMaterials and Biomedical EngineeringUniversity of Texas at El PasoEl Paso TX 79968-0521USA

The structure-property relationship in heat-affected zone (HAZ)of a low-carbon steel bearing V-N subjected to gasshielded arc welding was explored.The microstructural characteristics of base metal (BM),coarse-grained HAZ (CGHAZ),fine-grained HAZ,and intercritical HAZ were significantly different.The effect of grain-refinement strengthening and transformation hardening on HAZ contributed to equivalent hardness of 260.8-278.5 HV in comparison with BM hardness of 272.0 HV.Moreover,excellent impact toughness at -20 ℃ was obtained because of high resistance to crack propagation by high-misorientation boundaries,leading to impact fracture consisting of dimples.In CGHAZ,free N was partly fixed by V(C,N)precipitates,such that the deterioration effect of N on toughness was considered to be nearly eliminated.In comparison with CGHAZ,weld metal contained higher fraction of acicular ferrite with fine plates,while the impact toughness was inferior because of the detrimental influence of coarse inclusions from the welding wire.The nanoscale V(C,N)precipitates in CGHAZ had weak effect on toughness because of small size.

关键词： V-N microalloying Heat-affected zone Acicular ferrite Hardness Toughness Gas-shielded arc welding V-N microalloyed steel

Influence of Vanadium Content on Hot Deformation Behavior of Low-Carbon Boron Microalloyed Steel

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Acta Metallurgica Sinica(English Letters) 2020年第5期33卷 705-715页

作者： Kwang-Su Kim lin-xiu du Hyo-sung Choe Tae-Hyong Lee Gyong-Chol Lee Department of Materials Science and Engineering Kim Chaek University of TechnologyPyongyang 999093Democratic People’s Republic of Korea State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China

Single-pass compression tests were performed to investigate the hot deformation behavior of low-carbon boron microalloyed steel containing three various vanadium contents at 900-1100℃and strain rate of 0.01-10 s-1 using the MMS-300 thermal mechanical simulator.The flow stress curves of investigated steels were obtained under the different deformation conditions,and the effects of the deformation temperature and strain rate on the flow stress were discussed.The characteristic points of flow stress were obtained from the stress dependence of strain hardening rate;the activation energy of investigated steels was determined by the regression analysis;the flow stress constitutive equations were developed;the effect of vanadium content on the flow stress and dynamic recrystallization(DRX)was investigated.The result showed that the flow stress and activation energy(3-6.5 kJ mol-1)of the steel containing 0.18 wt%V were significantly higher than those of the steels with0.042 wt%and 0.086 wt%V,which was related to the increase in solute drag and precipitation effects for higher vanadium content.DRX analysis showed that the addition of vanadium can delay the initiation and the rate of DRX.

关键词： Boron microalloyed steel Vanadium Flow stress Hot deformation Dynamic recrystallization

Corrosion Behavior of High-Strength Steel for Flexible Riser Exposed to CO_2-Saturated Saline Solution and CO_2-Saturated Vapor Environments

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Acta Metallurgica Sinica(English Letters) 2019年第5期32卷 607-617页

作者： Da-Zheng Zhang xiu-Hua Gao lin-xiu du Hong-Xuan Wang Zhen-Guang Liu Ning-Ning Yang R.D.K.Misra State Key Laboratory of Rolling and Automation Northeastern University Neptune Offshore Engineering Development Co. Ltd School of Material Science and Engineering Jiangsu University of Science and Technology Department of Metallurgical Materials and Biomedical Engineering University of Texas at El Paso

The corrosion behavior of high-strength steel used for flexible riser exposed to CO_(2-)saturated saline solution and CO_(2-) saturated vapor environments was studied through immersion experiment and electrochemical corrosion experiment. The corrosion behavior and mechanism of the tested steel were analyzed on the basis of corrosion kinetics, nature of corrosion products, corrosion product morphology, elemental distribution and polarization curves. The experimental results showed that the microstructure of the tested steel was bainitic microstructure. The corrosive activity of the tested steel exposed to CO_(2-) saturated vapor environment was significantly lower than that exposed to CO_(2-) saturated saline solution environment.On prolonging the exposure time, the corrosion rate gradually decreased, the corrosion heterogeneity increased, and the dimensions of FeCO_3 crystals gradually became small. At later stages of corrosion, the corrosion current density decreased significantly and the anodic Tafel slope increased, indicating that the corrosion process was strongly inhibited. The corrosion mechanism of low-alloy steel with bainitic microstructure was proposed based on experimental results.

关键词： Flexible riser High-strength bainitic steel CO2 corrosion Electrochemical behavior

Stepwise colloidal lithography toward scalable and various planar chiral metamaterials

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Rare Metals 2024年第2期43卷 723-735页

作者： xiu Yang Yong Liu Fei-Liang Chen Qian-Qi lin Rohit Chikkaraddy Shan-Shan Huang Shi-lin Xian Yi-Dong Hou Jing-Lei du Liang-Ping Xia Chun-Lei du School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu610054China School of Optoelectronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu610054China Zhuhai Multiscale Optoelectronics Technology Co. Ltd.Zhuhai915060China Hybrid Materials for Opto-Electronics Group Department of Molecules and MaterialsMESA+Institute for NanotechnologyMolecules Center and Center for Brain-Inspired Nano SystemsFaculty of Science and TechnologyUniversity of Twente7500 AEEnschedeThe Netherlands School of Physics and Astronomy University of BirminghamBirminghamB152TTUK College of Physics Sichuan UniversityChengdu610065China Key Laboratory of Micro Nano Optoelectronic Devices and Intelligent Perception Systems Yangtze Normal UniversityChongqing408100China

Chiral metamaterials(CMs)composed by artificial chiral resonators have attracted great attentions in the recent decades due to their strong chiroptical resonance and identifiable interaction with chiral materials,facilitating practical applications in chiral biosensing,chiral emission,and display technology.However,the complex geometry of CMs improves the fabrication difficulty and hinders their scalable fabrication for practical applications,especially in the visible and ultraviolet wavelengths.One potential strategy is the colloidal lithography that enables parallel fabrication for scalable and various planar structures.Here,we demonstrate a stepwise colloidal lithography technique that uses sequential deposition from multiple CMs and expand their variety and complexity.The geometry and optical chirality of building blocks from single deposition are systematically investigated,and their combination enables a significant extension of the range of chiral patterns by multiple-step depositions.This approach resulted in a myriad of complex designs with different characteristic sizes,compositions,and shapes,which are particularly beneficial for the development of nanophotonic materials.In addition,we designed a flexible chiral device based on PDMS,which exhibits a good CD value and excellent stability even after multiple inward and outward bendings.The excellent compatibility to various substrates makes the planar CMs more flexible in practical applications in microfluidic biosensing.

关键词： Chiral metamaterials Colloidal lithography Nanophotonics Metasurfaces Plasmonics Nanofabrications Flexible devices

Construction of an immune-related gene signature for overall survival prediction and immune infiltration in gastric cancer

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 919-932页

作者： Xiao-Ting Ma xiu Liu Kai Ou lin Yang Department of Medical Oncology Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100021China

BACKGROUND Treatment options for patients with gastric cancer(GC)continue to improve,but the overall prognosis is poor.The use of PD-1 inhibitors has also brought benefits to patients with advanced GC and has gradually become the new standard treatment option at present,and there is an urgent need to identify valuable biomarkers to classify patients with different characteristics into subgroups.AIM To determined the effects of differentially expressed immune-related genes(DEIRGs)on the development,prognosis,tumor microenvironment(TME),and treatment response among GC patients with the expectation of providing new biomarkers for personalized treatment of GC populations.METHODS Gene expression data and clinical pathologic information were downloaded from The Cancer Genome Atlas(TCGA),and immune-related genes(IRGs)were searched from ImmPort.DEIRGs were extracted from the intersection of the differentially-expressed genes(DEGs)and IRGs lists.The enrichment pathways of key genes were obtained by analyzing the Kyoto Encyclopedia of Genes and Genomes(KEGGs)and Gene Ontology(GO)databases.To identify genes associated with prognosis,a tumor risk score model based on DEIRGs was constructed using Least Absolute Shrinkage and Selection Operator and multivariate Cox regression.The tumor risk score was divided into high-and lowrisk groups.The entire cohort was randomly divided into a 2:1 training cohort and a test cohort for internal validation to assess the feasibility of the risk model.The infiltration of immune cells was obtained using‘CIBERSORT,’and the infiltration of immune subgroups in high-and low-risk groups was analyzed.The GC immune score data were obtained and the difference in immune scores between the two groups was analyzed.RESULTS We collected 412 GC and 36 adjacent tissue samples,and identified 3627 DEGs and 1311 IRGs.A total of 482 DEIRGs were obtained.GO analysis showed that DEIRGs were mainly distributed in immunoglobulin complexes,receptor ligand activity,and signaling receptor activators.KEGG pathway analys

关键词： Differentially expressed immune-related gene Immunotherapy Gastric cancer Risk score