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Microstructural characterization in 7 at% Al-containing NiTi-based alloys

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Rare Metals 2014年第5期33卷 534-540页

作者： li-jing zheng Yi-Hui Guo Lei Zhou Xiao-li Zhang Hu Zhang Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Department of Military Logistics Military Transportation University

The microstructural evolution of Ni–42Ti–7Al and Ni–41Ti–7Al alloys as a function of solution and aging heat treatment was investigated using transmission electron microscopy（TEM）, electron probe, and X-ray diffraction（XRD）. The results reveal that the volume fraction of Ti2 Ni phase as well as its composition does not change significantly after as-solution treated at 1200 °C and aged at 850 °C. At the early stage of the aging treatment at 850 °C for 1 h, the cuboidal β＇ precipitate keeps coherency with the matrix; further aging, β＇ precipitate coarsens, and the semicoherency between the β/β＇ two phases are *** shape of coarsened β＇ precipitates changes to the globule, and the interface dislocations are introduced accompanied by the occurrence of semicoherent precipitates. Under the same heat treatment, compared to the Ni–42Ti–7Al alloy, the lattice misfits of the Ni–41Ti–7Al alloy between the β and β＇ two phases are larger, so the β＇ precipitates in Ni–41Ti–7Al alloy are coarsened severely and easily lose coherency with the matrix. The thermal stability of Ni–41Ti–7Al alloy is much worse when aging at 850 °C.

关键词： NiTi–Al alloys Ti2Ni phase β'precipitate Microstructure

Selective Laser Melting of an Al–Fe–V–Si Alloy:Microstructural Evolution and Thermal Stability

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Journal of Materials Science & Technology 2017年第4期33卷 389-396页

作者： Shao-Bo Sun li-jing zheng Jin-Hui liu Hu Zhang School of Materials Science and Engineering Beihang University Modern Manufacturing Engineering Center Heilongjiang Institute of Science and Technology

Selective laser melting was used to produce an aluminum alloy Al-8.5Fe-1.3V-1.7Si（wt%）. The effects of heat treatment on microstructure evolution and phase stability during long-term thermal exposure of the deposits were investigated. Results show that the microquasi-crystalline phase, Al12（Fe,V）3Si and AlmF e metastable phases coexisted with α-Al in the as-produced alloy. Annealing at 400 ℃ resulted in decomposition of microquasi-crystalline phase and supersaturated α-Al into Al12（Fe, V）3Si phase in the fusion zone, accompanied by the decrease in alloy hardness. The activation energy of this decomposition process was 115 k J/mol. A more homogenous microstructure was obtained after annealing at 400 °C for 60 min,which was resistant to coarsening exposed at 425 °C up to 500 h. The Al12（Fe,V）3Si and AlmF e phases were coarsened at 475 and 525℃ with increasing the exposure time. Coarsening of Al12（Fe,V）3Si phase was attributed to a combination of volume diffusion and grain boundary diffusion mechanism of Fe. Heat treatment at 600℃ resulted in accelerated microstructure coarsening and formation of large-sized equilibrium phases, which signi？cantly degraded the room temperature microhardness.

关键词： Selective laser melting Al–Fe–V–Si alloy Microstructural development Thermal stability Microhardness

Evolution of carbides on surface of carburized MSONiL bearing steel

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Journal of Iron and Steel Research International 2018年第11期25卷 1198-1211页

作者： Jiang-long lian li-jing zheng Fang-fang Wang Hu Zhang School of Materials Science and Engineering Beihang UniversityBeijing 100191China

The dissolution and precipitation behaviors of the carbides in carburized M50NiL steel were derived from different solution and tempering *** four kinds of carbides of (V,Cr)-rich MC,(Mo,Fe)-rich M2C,Fe-rich M3C and (Fe,Cr)-rich M7C3 were obtained from the carburized M50NiL steel after different heat *** key carbides of carbufized M50NiL steel were proved to be tough V-rich MC and Cr-rich *** highest hardness (634 HV)and the optimal surface structure with 1.0% volume fraction of uniformly distributed MC carbides were obtained after the carbufized M50NiL steel was solution-treated at 1150 ℃ and tempered at 500 ℃.The quantitative statistics show that 63%of the MC carbides were less than 200 nm under that heat *** variety of carbides changed with solution and tempering *** the solution temperature increased from 1050 to 1150 ℃,the undissolved carbides were proved to be Fe-rich M7C3,Mo-fich MC and (Mo,Fe)-fich ***,the equivalent content of V-rich MC was found increased when the tempering temperature changed from 500 to 550 ℃.The combination of high-temperature solution and low-temperature tempering is recommendable heat treatment for the high hardness as well as the tiny and uniformly distributed carbides.

关键词： M50NiL steel Carbide Carburization Hardness Heat treatment

Microstructural evolution of Ti–47Al–2Cr–2Nb–0.8B alloy prepared by semi-solid process

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Rare Metals 2020年第11期39卷 1262-1266页

作者： li-jing zheng Jian-Ji Wang Hu Zhang School of Materials Science and Engineering Beijing University of Aeronautics and AstronauticsBeijing100191China

The refinement of large boride ribbons in the as-cast TiAl alloy is the essential issue for aerospace industry application,which is difficult to avoid by classical casting *** present paper seeks to explore the possibility of the semi-solid process in manufacturing Ti-47Al-2Cr-2Nb-0.8 B(at%)*** important result is that,except forming a nondendritic globular structure,the semi-solid process also plays a crucial role in refining large borides for the TiAl alloys with *** the current alloy,the long ribbon borides can be successfully converted to fine,equiaxed particles with an average size of 2-5μ***,subsequent proper heat treatment is necessary to control and achieve a fine,nearly fully lamellar *** key microstructure-refinement mechanism is due to the fine borides obtained during semisolid process,which act as the effective nucleation centers for the formation of interdendritic fine y grains,providing the pinning effect on priorα-grain *** results prove that semi-solid process can be an ideal candidate for the microstructure refinement in TiAl alloys.

关键词： TiAl alloy Microstructure Semi-solid process Borides Refinement

Microstructural refinement and enhanced mechanical properties of suction-cast NiTi-Al alloy for structural use

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Rare Metals 2022年第8期41卷 2739-2744页

作者： li-jing zheng ling Guo Fang-Fang Wang Ming-Zhen Ma Hu Zhang Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education School of Materials Science and EngineeringBeihang UniversityBeijing100191China School of Materials Science and Engineering Yanshan UniversityQinhuangdao066004China

A significant refinement of the microstructure of structural NiTi alloy was achieved through a combination of Al addition and fabrication by suction *** is attributed to the change from a layer-by-layer to volume solidification mode with Al content increasing,which causes a change in grain shape from columnar to ***,when compared with conventional casting,suction casting optimizes the microstructure of the alloy by refining the grain size and ensuring a homogeneous distribution of Ti2 Ni and Ni_(2)TiAl *** high cooling rate of suction casting also delays the formation ofβ'-Ni_(2)TiAl ***,this fine microstructure and uniform distribution of intermetallic phases result in the ultimate compressive strength of up to 2463.7 MPa,representing an improvement of 370 MPa over conventionally cast NiTi-Al alloy.

关键词： NiTi-Al intermetallic compound Suction casting Microstructure Compressive strength

Halysis Høeg,1932—An ancestral tabulate coral from the Ordos Basin,North China

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Journal of Palaeogeography 2020年第4期9卷 480-494页

作者： li-jing zheng Hong-Xia Jiang Ya-Sheng Wu Hong-Ping Bao Yue-Yang Zhang Jun-Feng Ren zheng-liang Huang Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China China United Coalbed Methane Corporation LTDBeijing 100011China Institute of Paleontology Hebei Geo UniversityShijiazhuang 050031Hebei ProvinceChina University of Chinese Academy of Sciences Beijing 100049China Research Institute of Petroleum Exploration and Development Changqing OilfieldXi'an 710021Shaanxi ProvinceChina

The problematic calcareous microfossil Halysis is abundant in the Middle Ordovician Darriwilian Stage of the western edge of the Ordos Basin,North *** rich and well-preserved specimens of Halysis in this area facilitate detailed studies for its skeletal construction and tube *** differs from calcified cyanobacteria and calcareous red and green algae in morphology,skeletal construction and microstructure,as well as reproduction *** typically consists of multiple juxtaposed parallel tubes arranged in sheets(‘multiple-tube'type)or is just composed of one tube(‘single-tube'type).In‘multiple-tube'Halysis,tube fission by bifurcation results from the insertion of a microcrystalline wall at the center of a mother *** study demonstrates for the first time that the tube walls of Halysis have a laminofibrous(fibronormal)microstructure,composed of fibrous calcite perpendicular to wall surface,and recognizes the‘single-tube'type Halysis composed of one tube;in addition,for the first time,this study finds out that‘multiple-tube'Halysis develops buddings from the conjunction of two tubes and‘single-tube'Halysis shows wide-angle Y-shaped *** on these findings,this study further compares Halysis with tabulate *** appears stratigraphically earlier than Catenipora and Aulopora,and has a smaller tube size.‘Multiple-tube'Halysis resembles Catenipora and‘single-tube'Halysis resembles Aulopora in skeletal construction and microstructure,and in their tube walls of laminofibrous microstructure composed of fibrous calcite perpendicular to the tube wall *** and Halysis are both characterized by the absence of septal *** similarities suggest that Halysis may be the ancestor of Catenipora-like and Aulopora-like tabulate corals.

关键词： Halysis Morphology Taxonomic affinity Middle Ordovician Tabulate coral Wuhai Inner Mongolia

Study on Multiplexing Ability of Identical Fiber Bragg Gratings in a Single Fiber

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Chinese Journal of Aeronautics 2011年第5期24卷 607-612页

作者： liU Jiansheng ZHANG jing li Xin zheng zheng School of Electronics and lnformation Engineering Beihang University Beijing 100191 China

The multiplexing ability of a novel multiplexing fiber Bragg grating （FBG） method based on Optical Time Domain Reflecto meter （OTDR） and Time Division Multiplexing TDM technologies has been theoretically analyzed and studied. This method permits the interrogation of hundreds of identical FBGs with low reflectivity in a single fiber, making the FBG sensors more applicable in the aerospace health monitoring engineering. The analysis shows that the multiplexing ability can be greatly improved if the FBG reflectivity is sufficiently low. And hence, an inexpensive large-scale distributed sensing system based on this method can be realized, When evaluating the multiplexing ability of this system, we propose for the first time that the interference effect of multi-reflections among FBGs should be taken into consideration.

关键词： Bragg gratings multiplexing low reflectivity multi-reflection interference effect

Understanding the defect chemistry of oxide nanoparticles for creating new functionalities:A critical review

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Science China Chemistry 2011年第6期54卷 876-886页

作者： li GuangShe,li liPing & zheng jing State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Fuzhou 350002,China 1. State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences Fuzhou 350002 China

This work presents a critical review on the studies of defect chemistry of oxide nanoparticles for creating new functionalities pertinent to energy applications including dilute-magnetic semiconductors,giant-dielectrics,or white light *** is placed on the relationships between the internal structure and defective surfaces of oxide nanoparticles and their synergy in tailoring the materials *** review is arranged in a sequence:(1) structural fundamentals of bulk oxides,using TiO2 as a model simple oxide to highlight the importance of polymorphs in tuning the electronic structures;(2) structural features of simple oxide nanoparticles distinct from the bulk,which show that nanoparticles can be considered as a special solid under the compression as originated from the surface defect dipole-dipole interactions;and(3) new functions achieved through extending the defect chemistry concept to the assembled architectures or multi-component oxide nanoparticles,in which defect surfaces enable the localized electrons or intermediate levels to produce giant dielectric performance or tunable light *** is concluded that understandings of defect chemistry provide diverse possibilities to manipulate electrons in oxide nanoparticles for functionalities in energy-relevant applications.

关键词： nanoparticles defect chemistry surfaces functionalities

CNKSR2 interactome analysis indicates its association with the centrosome/microtubule system

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Neural Regeneration Research 2025年第8期20卷 2420-2432页

作者： lin Yin Yalan Xu Jie Mu Yu Leng Lei Ma Yu zheng Ruizhi li Yin Wang Peifeng li Hai Zhu Dong Wang jing li Institute for Translational Medicine The Affiliated Hospital of Qingdao UniversityMedical CollegeQingdao UniversityQingdaoShandong ProvinceChina School of Basic Medicine Qingdao UniversityQingdaoShandong ProvinceChina College of life Sciences and School of PharmacyMedical CollegeQingdao UniversityQingdaoShandong ProvinceChina Department of Urology Qingdao Municipal Hospital Affiliated to Qingdao UniversityQingdaoShandong ProvinceChina

The protein connector enhancer of kinase suppressor of Ras 2(CNKSR2),present in both the postsynaptic density and cytoplasm of neurons,is a scaffolding protein with several protein-binding *** of the CNKSR2 gene have been implicated in neurodevelopmental disorders,particularly intellectual disability,although the precise mechanism involved has not yet been fully *** has demonstrated that CNKSR2 plays a role in facilitating the localization of postsynaptic density protein complexes to the membrane,thereby influencing synaptic signaling and the morphogenesis of dendritic ***,the function of CNKSR2 in the cytoplasm remains to be *** this study,we used immunoprecipitation and high-resolution liquid chromatography-mass spectrometry to identify the interactors of *** a combination of bioinformatic analysis and cytological experiments,we found that the CNKSR2 interactors were significantly enriched in the proteome of the *** also showed that CNKSR2 interacted with the microtubule protein DYNC1H1 and with the centrosome marker *** colocalization analysis confirmed the centrosomal localization of *** we downregulated CNKSR2 expression in mouse neuroblastoma cells(Neuro 2A),we observed significant changes in the expression of numerous centrosomal *** manipulation also affected centrosome-related functions,including cell size and shape,cell proliferation,and ***,we found that CNKSR2 interactors were highly enriched in de novo variants associated with intellectual disability and autism spectrum *** findings establish a connection between CNKSR2 and the centrosome,and offer new insights into the underlying mechanisms of neurodevelopmental disorders.

关键词： autism spectrum disorder centrosome CNKSR2 intellectual disability interactome mass spectrometry microtubule neurodevelopmental disease protein complexes protein-protein interactions