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Microstructural evolution and deformation behavior of friction stir welded twin-induced plasticity steel

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Journal of Materials Science & Technology 2024年第2期169卷 68-81页

作者： Ke Qiao Kuaishe Wang Jia Wang Zhengyang Hao Yating Xiang Peng Han Jun Cai Qi Yang Wen Wang School of metallurgical engineering National and Local Joint Engineering Research Center for Functional Materials ProcessingXi’an University of Architecture and TechnologyXi’an 710055China Shanghai Research Institute of Materials Shanghai 200437China

The weldability of twin-induced plasticity(TWIP)steel with ultra-high strength via friction stir welding(FSW)technique was investigated,and microstructural evolution and deformation behavior of whole and micro-zones of FSW TWIP joint were studied for the first *** results showed that the content of recrystallized grains in the stir zone(SZ)increased from 10.5%of basal material(BM)to 14.2%,and that of heat affected zone(HAZ)increased to 78.6%.The percentage of annealing twins decreased from 26.8%in BM to 11%in SZ,while increased to 35%in *** with the BM,the ultimate tensile strength and yield strength of the FSW joint increased to 1036 and 550 MPa,respectively,reaching 106.7%and 110.9%of BM,*** elongation of the entire joint was 50.5%,which was lower than that of BM due to the nonuniform deformation during the tensile *** engineering strain was mainly concentrated in BM and SZ and transferred to each other during the tensile test,while the engineering strain in HAZ was always the ***,the tensile fracture occurred in the *** order of ultimate tensile strength of micro-zones in the FSW joint was as follows:HAZ>BM≈*** order of yield strength was as follows:HAZ>BM>SZ.

关键词： Twin-induced plasticity steel Friction stir welding Microstructure Mechanical property Deformation behavior

Localization for mixed near-field and far-field sources under impulsive noise

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Journal of Systems engineering and Electronics 2024年第2期35卷 302-315页

作者： GAO Hongyuan ZHANG Yuze DU Ya’nan CHENG Jianhua CHEN Menghan college of Information and Communication engineering Harbin Engineering UniversityHarbin 150001China college of Intelligent Systems Science and engineering Harbin Engineering UniversityHarbin 150001China

In order to solve the problem that the performance of traditional localization methods for mixed near-field sources(NFSs)and far-field sources(FFSs)degrades under impulsive noise,a robust and novel localization method is *** eliminating the impacts of impulsive noise by the weighted out-lier filter,the direction of arrivals(DOAs)of FFSs can be estimated by multiple signal classification(MUSIC)spectral peaks *** on the DOAs information of FFSs,the separation of mixed sources can be ***,the estimation of localizing parameters of NFSs can avoid two-dimension spectral peaks search by decomposing steering *** Cramer-Rao bounds(CRB)for the unbiased estimations of DOA and range under impulsive noise have been *** experiments verify that the proposed method has advantages in probability of successful estimation(PSE)and root mean square error(RMSE)compared with existing localization *** can be concluded that the proposed method is effective and reliable in the environment with low generalized signal to noise ratio(GSNR),few snapshots,and strong impulse.

关键词： source localization far-field source(NFS) near-field source(FFS) impulsive noise Cramer-Rao bound(CRB)

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Recovery of scandium from silicate minerals by high-pressure leaching in sulfuric acid

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Journal of Rare Earths 2024年第7期42卷 1375-1384,I0007页

作者： Peng Yan Xiaoming Chen Likun Gao Bo Yang Faculty of metallurgical and Energy engineering Kunming University of Science and TechnologyKunming650093China Faculty of Land Resources engineering Kunming University of Science and TechnologyKunming650093China School of Chemistry and Chemical engineering Kunming UniversityKunming650214China

This study investigated the leaching of scandium from a Sc-bearing silicate *** Sc concentrate obtained by beneficiation pre-enrichment has 1.03×10^(−4) wt%Sc and 14.66 wt%*** main Sc-bearing minerals are limonite,chlorite,sericite,and hornblende,in the form of ***-pressure leaching(HPL)with sulfuric acid(98 wt%)and NaF was used to dispose this *** Sc leaching efficiency of 91.82%was obtained under the optimum conditions,which are pressure of 5.0×10^(5) Pa,A/O value of 1.1,L/S value of 1.8,NaF dosage of 2 wt%,at 130℃ for 6 *** X-ray diffraction(XRD)and scanning electron microscopy(SEM)results show that the residue is mainly quartz phase in the multi-hole *** with ordinary leaching for silicate,high-pressure leaching has significant advantages in saving acid and energy consumption.

关键词： Silicate minerals Scandium High-pressure Leaching Concentrated sulfuric acid Rare earths

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Improvement strategy on thermophysical properties of A_(2)B_(2)O_(7)-type rare earth zirconates for thermal barrier coatings applications:A review

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1147-1165页

作者： Zijian Peng Yuhao Wang Shuqi Wang Junteng Yao Qingyuan Zhao Enyu Xie Guoliang Chen Zhigang Wang Zhanguo Liu Yaming Wang Jiahu Ouyang School of Materials Science and engineering Harbin Institute of TechnologyHarbin 150001China School of Materials and metallurgical engineering Inner Mongolia University of Science&TechnologyBaotou 014010China

The A_(2)B_(2)O_(7)-type rare earth zirconate compounds have been considered as promising candidates for thermal barrier coating(TBC) materials because of their low sintering rate,improved phase stability,and reduced thermal conductivity in contrast with the currently used yttria-partially stabilized zirconia (YSZ) in high operating temperature *** review summarizes the recent progress on rare earth zirconates for TBCs that insulate high-temperature gas from hot-section components in gas *** on the first principles,molecular dynamics,and new data-driven calculation approaches,doping and high-entropy strategies have now been adopted in advanced TBC materials *** this paper,the solid-state heat transfer mechanism of TBCs is explained from two aspects,including heat conduction over the full operating temperature range and thermal radiation at medium and high *** paper also provides new insights into design considerations of adaptive TBC materials,and the challenges and potential breakthroughs are further highlighted for extreme environmental *** for improving thermophysical performance are proposed in two approaches:defect engineering and material compositing.

关键词： rare earth zirconates thermal barrier coatings defect engineering doping and compositing thermal conductivity thermal expansion

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Synthesis of Long-Chain Oligomeric Donor and Acceptors via Direct Arylation for Organic Solar Cells

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Chinese Journal of Chemistry 2024年第5期42卷 523-532页

作者： Yu Wu Xin-Yu He Xu-Min Huang Ling-Jun Yang Peng Liu Na Chen Chang-Zhi Li Shi-Yong Liu Jiangxi Provincial Key Laboratory of Functional Molecular Materials Chemistry College of MaterialsMetallurgical and ChemistryJiangxi University of Science and TechnologyGanzhouJiangxi341000 China Department of Polymer Science and engineering Zhejiang UniversityHangzhouZhejiang310027 China

The rapid synthesis of structurally complicated electron donors&acceptors still remains a major challenge in organic solar cells(OSC).In this work,we developed a highly efficient strategy to access long-chain oligomeric donor and acceptors for OSC applications.A series of cyclopentadithiophene(CPDT)and benzothiadiazole(BT)-basedπ-conjugated oligomers,i.e.,three oligomeric acceptors(BTDT)n-IC(n=1—3)and one long-chain oligomeric donor(BTDT)4-RD,are facilely synthesized by an atom-and step-economical,and labor-saving direct C—H arylation(DACH)reaction(i.e.,C—H/C—Br cross coupling).Note that(BTDT)4-RD involving five CPDT,four BT and two rhodamine(RD)building blocks is the longest oligomeric donor in the fullerene-free OSC devices ever *** dependence of the structure-property-performance correlation of(BTDT)n-IC(n=1—3)and(BTDT)4-RD on theπ-conjugation lengths is thoroughly investigated by opto-electrochemical measurements,bulk heterojunction(BHJ)OSC devices and ***(BTDT)1-IC:PBDB-T and(BTDT)4-RD:Y6 BHJs achieve power conversion efficiencies of 9.14%and 4.51%,*** findings demonstrate that DACH reaction is a powerful tool to tune the opto-electronic properties and device performances by regulating the lengths ofπ-conjugated oligomers with varied numbers of repeating units.

关键词： Long-chainπ-conjugated oligomer Organic solar cells Direct arylation Atom-economical synthesis Cyclopentadithiophene Benzothiadiazole C—H activation Conjugation Oligomers

Formation adaptation in obstacle-cluttered environments via MPC-based trajectory planning

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Science China(Information Sciences) 2024年第7期67卷 321-323页

作者： Yuda CHEN Zhongkui LI Department of Mechanics and engineering Science College of Engineering Peking University

Formation is a typical collective behavior in multiagent systems utilized in areas such as inspection, surveillance, and transportation. Commonly-used approaches to achieve formation include virtual structure [1], con...

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Effect of austenitizing condition on mechanical properties,microstructure and precipitation behavior of AISI H13 steel

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Journal of Iron and Steel Research(International) 2024年第1期31卷 143-156页

作者： An-gang Ning Yang Liu Rui Gao Stephen Yue Ming-bo Wang Han-jie Guo college of Materials Science and engineering Taiyuan University of TechnologyTaiyuan030024ShanxiChina Department of Mining and Materials engineering McGill UniversityMontrealQCH3A 0C5Canada ASSAB Tooling Technology(Chongqing)Co. Ltd.Chongqing401120China School of metallurgical and Ecological engineering University of Science and Technology BeijingBeijing100083China

The effects of austenitizing temperature(1223,1303,and 1373 K)and holding time(1-1500 s)on the microstructure,mechanical properties,and precipitation behavior of the H13 hot work die steel were *** results indicate a softening phenomenon when H13 steel is austenitized at 1303 K beyond 900 s and 1373 K beyond 600 s,*** the sample held for 1200 s,the tensile strength is found capable of reaching up to 2.2 GPa when quenched from a temperature above 1303 ***,prior-austenite grain size increases with the increase in austenitizing *** kinetic behavior of the precipitates(mainly MC-type carbides)in H13 steel could be elaborated through the principles set forth by the Arrhenius and Avrami ***,the comprehensive strengthening of the H13 steel was discussed in *** results show that the activation energy of the transformed fraction of carbides is higher than that of the diffusion process for common alloying elements(Cr,V,Mo,and Ni)found in the *** suggests that it would be difficult for precipitates to dissolve into the matrix when H13 steel is austenitized at high *** the increasing austenitizing temperature,the precipitation fraction decreases,and the dislocation density *** dislocation strengthening is regarded as the dominant strengthening contributed to yield strength in as-quenched H13 steel.

关键词： H13 steel Austenitizing Mechanical property Precipitation behavior Comprehensive strengthening

Novel wood-plastic composite fabricated via modified steel slag:Preparation,mechanical and flammability properties

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International Journal of Minerals,Metallurgy and Materials 2024年第9期31卷 2110-2120页

作者： Ling Zhao Kai Zhao Zhenwei Shen Yifan Wang Xiaojie Xia Hao Zhang Hongming Long School of metallurgical engineering Anhui University of TechnologyMa’anshan 243032China School of Civil engineering and Architecture Anhui University of TechnologyMa’anshan 243032China School of Materials Science and engineering Anhui University of TechnologyMa’anshan 243032China Key Laboratory of metallurgical Emission Reduction and Resources Recycling(Anhui University of Technology) Ministry of EducationMa’anshan 243002China

A novel method was developed to enhance the utilization rate of steel slag(SS).Through treatment of SS with phosphoric acid and aminopropyl triethoxysilane(KH550),we obtained modified SS(MSS),which was used to prepare MSS/wood-plastic composites(MSS/WPCs)by replacing talcum powder(TP).The composites were fabricated through melting blending and hot *** mechanical and combustion properties,which comprise heat release,smoke release,and thermal stability,were systematically *** can improve the mechanical strength of the composites through grafting reactions between wood powder and ***,MSS/WPC#50(16wt%MSS)with an MSS-to-TP mass ratio of 1:1 exhibited optimal comprehensive *** with those of WPC#0 without MSS,the tensile,flexural,and impact strengths of MSS/WPC#50 were increased by 18.5%,12.8%,and 18.0%,***,the MSS/WPC#50 sample achieved the highest limited oxygen index of 22.5%,the highest vertical burning rating at the V-1 level,and the lowest horizontal burning rate at 44.2 mm/*** formation of a dense and stable char layer led to improved thermal stability and a considerable reduction in heat and smoke releases of MSS/WPC#***,the partial replacement of TP with MSS slightly compromised the mechanical and flame-retardant properties,possibly due to the weak grafting caused by SS powder *** findings suggest the suitability of MSS/WPCs for high-value-added applications as decorative panels indoors or outdoors.

关键词： modified steel slag wood–plastic composites preparation method mechanical property flame retardant

Numerical Investigation of the Angle of Attack Effect on Cloud Cavitation Flow around a Clark-Y Hydrofoil

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Computer Modeling in engineering & Sciences 2024年第6期139卷 2947-2964页

作者： Di Peng Guoqing Chen Jiale Yan Shiping Wang college of engineering Peking UniversityBeijing100871China college of Shipbuilding engineering Harbin Engineering UniversityHarbin150001China

Cavitation is a prevalent phenomenon within the domain of ship and ocean engineering,predominantly occurring in the tail flow fields of high-speed rotating propellers and on the surfaces of high-speed underwater *** re-entrant jet and compression wave resulting from the collapse of cavity vapour are pivotal factors contributing to cavity ***,these phenomena significantly modulate the evolution of cavitation *** this paper,numerical investigations into cloud cavitation over a Clark-Y hydrofoil were conducted,utilizing the Large Eddy Simulation(LES)turbulence model and the Volume of Fluid(VOF)method within the OpenFOAM *** analysis of results obtained at different angles of attack is undertaken.A discernible augmentation in cavity thickness is observed concomitant with the escalation in attack angle,alongside a progressive intensification in pressure at the leading edge of the hydrofoil,contributing to the suction *** results can serve as a fundamental point of reference for gaining a deeper comprehension of cloud cavitation dynamics.

关键词： Cloud cavitation re-entrant jet compression wave clark-Y hydrofoil