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Microstructure evolution and strengthening mechanism of high -performance powder metallurgy TA15 titanium alloy by hot rolling

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1426-1436页

作者： Ying Gao Ce Zhang Jiazhen Zhang Xin Lu Beijing advanced Innovation center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsInstitute for Advanced Ma-terials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China National Engineering Research center for advanced Rolling technology National Engineering Research Center for Flat Rolling EquipmentInstitute of Engin-eering TechnologyUniversity of Science and Technology BeijingBeijing 100083China

Hot deformation of sintered billets by powder metallurgy(PM)is an effective preparation technique for titanium alloys,which is more significant for high-alloying *** this study,Ti–6.5Al–2Zr–Mo–V(TA15)titanium alloy plates were prepared by cold press-ing sintering combined with high-temperature hot *** microstructure and mechanical properties under different process paramet-ers were *** microscope,electron backscatter diffraction,and others were applied to characterize the microstructure evolution and mechanical properties strengthening *** results showed that the chemical compositions were uniformly dif-fused without segregation during sintering,and the closing of the matrix craters was accelerated by increasing the sintering *** block was hot rolled at 1200℃ with an 80%reduction under only two passes without *** strength and elongation of the plate at 20–25℃ after solution and aging were 1247 MPa and 14.0%,respectively,which were increased by 24.5%and 40.0%,respect-ively,compared with the as-sintered alloy at 1300℃.The microstructure was significantly refined by continuous dynamic recrystalliza-tion,which was completed by the rotation and dislocation absorption of the substructure surrounded by low-angle grain *** hot rolling combined with heat treatment,the strength and plasticity of PM-TA15 were significantly improved,which resulted from the dense,uniform,and fine recrystallization structure and the synergistic effect of multiple slip systems.

关键词： elemental powder powder metallurgy titanium alloy hot rolling strength and plasticity

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In-situ analysis of laser-induced breakdown spectra for online monitoring of femtosecond laser machining of sapphire

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Science China(Technological Sciences) 2024年第1期67卷 73-82页

作者： SHANGGUAN ShiYong ZHANG JianGuo LI ZhanZhu SHI Wei WANG WenKe QI DongFeng ZHENG HongYu center for advanced Laser Manufacturing(CALM) Shandong University of TechnologyZibo 255000China

Laser-induced breakdown spectroscopy(LIBS)is widely used for elemental ***,its application for monitoring and analyzing a laser machining process by examining the changes in spectral information warrants further *** this study,we investigate the effect of laser parameters on the spectra,variations in the time-resolved plasma emission spectra,and the relationship between the morphology of craters and plasma plume evolution during the femtosecond(fs)laser ablation of *** Boltzmann plot method and Stark’s broadening model are employed to estimate the temporal temperature and electron density of the plasma plume,revealing the process of plasma *** study aims to demonstrate the feasibility of LIBS for online monitoring of laser processing through experimental data and theoretical explanations.

关键词： laser-induced breakdown spectroscopy plasma plume online monitoring sapphire

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A novel high-Cr CoNi-based superalloy with superior high-temperature microstructural stability, oxidation resistance and mechanical properties

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1373-1381页

作者： Xiaorui Zhang Min Zou Song Lu Longfei Li Xiaoli Zhuang Qiang Feng Beijing advanced Innovation center for Materials Genome Engineering State Key Laboratory for Advanced MetalsUniversity of Science and Technology BeijingBeijing 100083China

A novel multicomponent high-Cr CoNi-based superalloy with superior comprehensive performance was prepared,and the evaluation of its high-temperature microstructural stability,oxidation resistance,and mechanical properties was conducted mainly using its cast polycrystalline *** results disclosed that the morphology of theγ′phase remained stable,and the coarsening rate was slow during the long-term aging at 900–1000℃.The activation energy forγ′precipitate coarsening of alloy 9CoNi-Cr was(402±51)kJ/mol,which is higher compared with those of CMSX-4 and some other Ni-based and Co-based ***,there was no indica-tion of the formation of topologically close-packed phases during this *** these factors demonstrated the superior microstructural stability of the *** mass gain of alloy 9CoNi-Cr was 0.6 mg/cm^(2) after oxidation at 1000℃ for 100 h,and the oxidation resistance was comparable to advanced Ni-based superalloys CMSX-4,which can be attributed to the formation of a continuous Al_(2)O_(3) protective ***,the compressive yield strength of this cast polycrystalline alloy at high temperatures is clearly higher than that of the conventional Ni-based cast superalloy and the compressive minimum creep rate at 950℃ is comparable to that of the conventional Ni-based cast superalloy,demonstrating the alloy’s good mechanical properties at high *** is partially because high Cr is bene-ficial in improving theγandγ′phase strengths of alloy 9CoNi-Cr.

关键词： CoNi-based superalloys microstructure coarsening oxidation mechanical properties

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Halogen-bond induced unusual polyhalogen anions formation in hydrogen-bonded frameworks to secure iodine sequestration

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Nano Research 2024年第7期17卷 6766-6772页

作者： Yi Xie Pengling Huang Qiang Gao Shiyu Wang Jianchen Wang Gang Ye Collaborative Innovation center of advanced Nuclear Energy technology Institute of Nuclear and New Energy TechnologyTsinghua UniversityBeijing 100084China

Safe confinement of fission iodine isotopes for long-term radioactive waste disposal remains a formidable challenge,as conventional sorbents provide inherently weak iodine-host *** report here a novel halogen bond(X-bond)directed strategy to sequester volatile iodine in hydrogen-bonded(H-bonded)frameworks with unprecedented ***-assisted Hbonded frameworks bearing open halide sites are developed,showing distinctive iodine encapsulation behaviors without compromising the *** crystallographic evidence indicates the formation of X-bonds,i.e.,I–I···Cl^(−) and I–I···Br^(−),within the confined pore *** polyhalogen anions,i.e.,[I_(2)Cl_(2)]^(2−)and[I_(2)Br_(2)]^(2−),sustained in H-bonded frameworks are identified for the first *** X-bond reinforced host-guest interaction affords robust iodine trapping without leaking out even at elevated temperatures up to 180℃.By integrating the halogen-bond chemistry with H-bonded frameworks,this study offers fresh concepts for developing effective host reservoirs to secure fission iodine isotopes from spent fuel reprocessing off-gases.

关键词： halogen-bond chemistry anion coordination chemistry hydrogen-bonded organic frameworks polyhalogen anions iodine confinement

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CFD-DEM simulation of high density particles fluidization behaviors in 3D conical spouted beds

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Particuology 2024年第5期88卷 266-281页

作者： Lin Jiang Mofan Qiu Rongzheng Liu Bing Liu Youlin Shao Malin Liu Institute of Nuclear and New Energy technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyTsinghua UniversityBeijing 100084China

The spouted bed has been used in the coating process of high-density nuclear fuel *** particle fluidization behaviors in pseudo-2D and 3D spouted beds were simulated and *** effects of four independent variables(cone angle,particle density,inlet gas velocity,and particle loading)on particle fluidization behaviors in the 3D spouted bed were investigated *** cone angle effect on fluidization mechanism was studied quantitatively first time.A new fluidization quality index was proposed based on the particle entrainment principle,and an extreme value was obtained when the cone angle was 60°,considered to be the optimum value for the 3D conical spouted *** was indicated the gas–solid contact efficiency can be kept up if the gas velocity was proportional to ρ_(p)^(0.65) and N_(p)^(0.78) when the particle density or loading was *** results will be useful for geometry and operation parameters design of the 3D conical spouted bed and helpful for developing the fluidization mechanism of high-density particles.

关键词： Spouted bed High-density particle CFD-DEM Fluidization quality index Particle loading

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CFD-DEM simulation of fluorination reaction in fluidized beds with local grid and time refinement method

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Particuology 2024年第1期84卷 145-157页

作者： Mofan Qiu Lin Jiang Rongzhen Liu Yaping Tang Malin Liu Institute of Nuclear and New Energy technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyTsinghua UniversityBeijing100084China

The gas-solid reaction process with wide particle size distribution is extensively used in the chemical engineering field,especially the particle reacts with the gas gradually,such as fluorination reactions in fluidized *** the computational fluid dynamics-discrete element method(CFD-DEM)is used for the coupling simulation of multiphase and polydisperse particle reaction system,the grid size directly affects the accuracy of flow field information and simulation of chemical ***,particle calculation time step will directly affect the efficiency of coupling *** this work,a local grid and time step refinement method is proposed to simulate multiphase and polydisperse particle fluid-ization reaction *** this method,the refined DEM grids are automatically generated in the computational domain around the fine particles,and the detailed fluid phase information is obtained with the interpolation *** the two-phase coupling process,particles are divided into different groups based on physical properties,each group has its own independent time *** multistage conical-cylindrical spouted bed is proposed for the fluorination reaction process;the operating gas ve-locity range of the polydisperse particle system is extended by the new design while the particle size distribution changes with the gas-solid reaction *** is demonstrated that the local grid and time step refinement method can improve the accuracy and efficiency of the traditional CFD-DEM method in the reaction process simulation,which describes a polydisperse particle system with wide particle size *** at improving the simulation accuracy and efficiency,this paper will be helpful for simulating the particle reaction process in the gas-solid fluidized bed and beneficial for the development of the CFD-DEM method.

关键词： CFD-DEM Polydisperse particle Two-phase flow Fluidized bed

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Anion-hosting cathodes for current and late-stage dual-ion batteries

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Science China Chemistry 2024年第5期67卷 1485-1509页

作者： Miao Zhang Wenyong Zhang Fan Zhang Chun-Sing Lee Yongbing Tang School of Chemistry and Materials Science Guangdong University of EducationGuangzhou 510303China advanced Energy Storage technology Research center Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China center of Super-Diamond and advanced Film(COSDAF) City University of Hong KongKowloon 999077China

Anion-hosting cathodes capable of reversibly storing large-size anions play a leading role in dual-ion batteries(DIBs). The purpose of the present review is to summarize the most promising anion-hosting cathodes for current and late-stage DIBs. This review first summarizes the developments in conventional graphite cathodes, especially the latest advances in the graphiterelated research. Next, organic cathodes for the anion storage are discussed, including aromatic amine polymers, heterocyclic polymers, bipolar compounds, and all-carbon-unsaturated compounds. Then, the review focuses on the conversion-type cathodes with high theoretical specific capacities. Finally, the future research directions of the cathodes of DIBs are proposed.

关键词： dual-ion batteries organic cathodes graphite cathodes conversion-type cathodes

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Effect of bipolar-plates design on corrosion,mass and heat transfer in proton-exchange membrane fuel cells and water electrolyzers:A review

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1599-1616页

作者： Jiuhong Zhang Xiejing Luo Yingyu Ding Luqi Chang Chaofang Dong Key Laboratory for Corrosion and Protection(MOE) Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China Beijing advanced Innovation center for Materials Genome Engineering Beijing 100083China

Attaining a decarbonized and sustainable energy system,which is the core solution to global energy issues,is accessible through the development of hydrogen ***-exchange membrane water electrolyzers(PEMWEs)are promising devices for hydrogen production,given their high efficiency,rapid responsiveness,and *** plates account for a relatively high percentage of the total cost and weight compared with other components of ***,optimization of their design may accelerate the promotion of *** paper reviews the advances in materials and flow-field design for bipolar ***,the working conditions of proton-exchange membrane fuel cells(PEMFCs)and PEMWEs are compared,including reaction direction,operating temperature,pressure,input/output,and ***,the current research status of bipolar-plate substrates and surface coatings is summarized,and some typical channel-rib flow fields and porous flow fields are ***,the effects of materials on mass and heat transfer and the possibility of reducing corrosion by improving the flow field structure are ***,this review discusses the potential directions of the development of bipolar-plate design,including material fabrication,flow-field geometry optimization using threedimensional printing,and surface-coating composition optimization based on computational materials science.

关键词： bipolar-plates flow design mass and heat transfer corrosion water electrolyzers fuel cells

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Hierarchical Voronoi Structure Inspired by Cat Paw Pads Substantially Enhances Landing Impact Energy Dissipation

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Journal of Bionic Engineering 2024年第4期21卷 1847-1861页

作者： Da Lu Baoqing Pei Yangyang Xu Mengyuan Hu Shijia Zhang Le Zhang Xin Huang Yangwei Wang Xueqing Wu Beijing Key Laboratory for Design and Evaluation technology of advanced Implantable&Interventional medical Devices Beijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringBeihang University100083BeijingChina National Key Laboratory of Science and technology on Materials under Shock and Impact Beijing Institute of Technology100081BeijingChina Shenzhen Institute of Beihang University 518000ShenzhenChina

When a human lands from a high drop,there is a high risk of serious injury to the lower *** the other hand,cats can withstand jumps and falls from heights without being fatally wounded,largely due to their impact-resistant paw *** aim of the present study was to investigate the biomechanism of impact resistance in cat paw pads,propose an optimal hierarchical Voronoi structure inspired by the paw pads,and apply the structure to bionic cushioning shoes to reduce the impact force of landing for *** microstructure of cat paw pads was observed via tissue section staining,and a simulation model was reconstructed based on CT to verify and optimize the structural cushioning *** distribution pattern,wall thickness of compartments,thickness ratio of epidermis and dermis,and number of compartments in the model were changed and simulated to achieve an optimal composed structure.A bionic sole was 3D-printed,and its performance was evaluated via compression test and a jumping-landing *** results show that cat paw pads are a spherical cap structure,divided from the outside to the inside into the epidermis,dermis,and compartments,each with different cushioning capacities.A finite element simulation of different cushioning structures was conducted in a cylinder with a diameter of 20 mm and a height of 10 mm,featuring a three-layer *** optimal configuration of the three layers should have a uniform distribution with 0.3–0.5 mm wall thickness,a 1:1–2 thickness ratio of epidermis and dermis,and 100–150 compartments.A bionic sole with an optimized structure can reduce the peak impact force and delay the peak arrival *** energy absorption rate is about 4 times that of standard *** jumping 80,100,and 120 cm,the normalized ground reaction force is also reduced by 8.7%,12.6%and 15.1%compared with standard *** study provides theoretical and technical support for effective protection against human lower limb landing injuries.

关键词： Cat paw pads Hierarchical Voronoi structure Landing impact Energy dissipation Bionic sole

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Reevaluation by the CRISPR/Cas9 knockout approach revealed that multiple pluripotency-associated lncRNAs are dispensable for pluripotency maintenance while Snora73a/b is essential for pluripotency exit

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Science China Life Sciences 2024年第10期67卷 2198-2212页

作者： Zhen Li Xuefei Li Jingxia Lin Yangming Wang Huiqing Cao Jiajian Zhou Institute of Molecular Medicine College of Future TechnologyPeking University Dermatology Hospital Southern Medical University Beijing advanced center of RNA Biology (BEACON) Peking University

Many long noncoding RNAs(lncRNAs) have been identified through siRNA-based screening as essential regulators of embryonic stem cell(ESC) pluripotency. However, the biological and molecular functions of most lncRNAs remain unclear. Here, we employed CRISPR/Cas9-mediated knockout technology to explore the functions of 8 lncRNAs previously reported to promote pluripotency in mouse ESCs. Unexpectedly, all of these lncRNAs were dispensable for pluripotency maintenance and proliferation in mouse ESCs when disrupted individually or in combination. Single-cell transcriptomic analysis also showed that the knockout of these lncRNAs has a minimal impact on pluripotency gene expression and cell identity. We further showed that several small hairpin RNAs(shRNAs) previously used to knock down lncRNAs caused the downregulation of pluripotency genes in the corresponding lncRNA-knockout ESCs, indicating that off-target effects likely responsible for the pluripotency defects caused by these shRNAs. Interestingly, linc1343-knockout and linc1343-knockdown ESCs failed to form cystic structures and exhibited high expression of pluripotency genes during embryoid body(EB) differentiation. By reintroducing RNA products generated from the linc1343 locus, we found that two snoRNAs, Snora73a and Snora73b, but not lncRNAs, could rescue pluripotency silencing defects during EB differentiation of linc1343 knockout ESCs. Our results suggest that the 8 previously annotated pluripotency-regulating lncRNAs have no overt functions in conventional ESC culture; however, we identified snoRNA products derived from an annotated lncRNA locus as essential regulators for silencing pluripotency genes.

关键词： long noncoding RNAs embryonic stem cells CRISPR/Cas9 snoRNAs stem cell differentiation

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