检索结果-南通市图书馆

Microstructure and strength of a tantalum-tungsten alloy after cold rolling from small to large strains

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第24期83卷 34-48页

作者： Guoqiang Ma Darcy A.Hughes Andrew W.Godfrey Qiang Chen Niels Hansena Guilin Wu College of Materials Science and Engineering Chongqing UniversityChongqing400044China Department of Mechanical Engineering Technical University of DenmarkDK-2800KgsLyngbyDenmark Fremont CAUSA Laboratory of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing100084China Southwest Technology and Engineering Research Institute Chongqing400039China Technical University of Denmark Risoe CampusDK-4000RoskildeDenmark Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing100083China

Microstructural evolution of a refractory tantalum-tungsten alloy(Ta-4%W)after cold rolling from small to large von-Mises strains(0.12-2.7)was quantitatively studied using transmission electron *** subdivision was observed to take place at two *** necessary boundaries nearly paralleling to slip planes enclosed volumes further divided by diffuse cells and by remnants of Taylor *** increasing strain,the diffuse cells evolved into clear incidental dislocation boundaries enclosing cells,while the Taylor lattices *** subdivision was thus intermediate between those observed in cell forming and in non-cell forming ***,the average misorientation angle across all boundaries increased while the average boundary spacing *** of the microstructural parameters at each strain level were found to exhibit universal scaling *** microstructural evolution was found closely linking to the observed high strength and strain hardening of this *** on measured microstructural parameters,the flow stress was calculated utilizing linearly addition of the strengthening by solutes,incidental dislocation boundaries(Taylor strengthening)and geometrically necessary boundaries(Hall-Petch equation).The relative contribution of each strength mechanism evolved with increasing strain and with microstructural evolution:solutes and friction stress dominated at small strains while boundaries dominated at larger *** strengths were in close agreement with experimental tension tests and demonstrated an unexpectedly high and continuous parabolic hardening without transition across this large strain range.

关键词： tantalum Deformation microstructure Geometrically necessary boundaries Taylor lattices Flow stress

Prediction of stable high-pressure structures of tantalum nitride TaN2

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2019年第10期35卷 2297-2304页

作者： Wandong Xing Zijie Wei Rong Yu Fanyan Meng Department of Physics University of Science and Technology BeijingBeijing Engineering Research Center of Detection and Application for Weak Magnetic FieldBeijing100083China School of Automation University of Science and Technology BeijingBeijing100083China National Center for Electron Microscopy in Beijing School of Materials Science and EngineeringKey Laboratory of Advanced Materials of Ministry of Education of ChinaState Key Laboratory of New Ceramics and Fine ProcessingTsinghua UniversityBeijing100084China

Structure searches based on a combination of first-principles calculations and a particle swarm optimization technique unravel two new stable high-pressure structures(C2/m and Cmce) for Ta N2. The structural features, mechanical properties, formation enthalpies, electronic structure, and phase diagram of Ta N2 are fully investigated. Being mechanically and dynamically stable, the two phases could be made metastable experimentally at ambient conditions.

关键词： Particle swarm optimization First-principles tantalum nitride Crystal structure High pressure

Transfer or blockage:Unraveling the interaction between deformation twinning and grain boundary in tantalum under shock loading with molecular dynamics

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第25期156卷 118-128页

作者： Z.C.Meng M.M.Yang A.H.Feng S.J.Qu F.Zhao L.Yang J.H.Yao Y.Yang Q.B.Fan H.Wang Interdisciplinary Centre for Additive Manufacturing (ICAM) School of Materials and ChemistryUniversity of Shanghai for Science and TechnologyShanghai 200093China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China School of Materials Science and Engineering Tongji UniversityShanghai 201804China Academy for Advanced Interdisciplinary Studies Southern University of Science and TechnologyShenzhen 518055China National Key Laboratory of Science and Technology on Materials Under Shock and Impact School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401135China

The interaction between{112}deformation twinning and grain boundary in coaxial polycrystalline tantalum under shock compression was studied with molecular dynamics simulation under different grain pair misorientation angles(MA)and geometric compatibility factor(m’).Generally,in the coaxial polycrystal,the value of MA determines the occurrence of twin transfer(TT)or twin blockage(TB),i.e.,twin transfer occurs at MA≤29°with twin blockage *** TT,the value of m’affects the selection of twin variants.,i.e.,the twin system with a larger m’is easier to *** morphology of twin pairs is ruler-shaped and lenticular under TT and TB,respectively,with different thickening mechanisms,including grain boundary dislocation emission.

关键词： Plasticity Grain boundary Twin Atomistic simulation tantalum

Cell behaviors on surface of pure tantalum with nano-dimpled structure

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2019年第6期38卷 543-551页

作者： Jun-Wei Ma Rui Zan Wen-Zhi Chen Jia-Hua Ni Xiao-Nong Zhang State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China California Nanosystems Institute University of CaliforniaLos AngelesCaliforniaCA 90095USA

tantalum exhibits excellent biocompatibility and good chemical stability, which has been employed in dental and orthopedic *** local microenvironment of the surface of implants influence determines the surrounding cell *** this work, nano-dimpled structure on the surface of pure tantalum was fabricated by electrochemical *** surface morphology of the nano-dimpled structure was observed, and the dimensions of the nano-dimpled structure were measured by scanning electron microscopy(SEM).The surface roughness of the sample with nano-dimpled structure was measured by atomic force microscopy(AFM).The results show that the diameter of nano-dimpled ranges from 40 to 180 nm, and the higher the applied voltage, the larger the ***, nano-dimpled structure has good *** vitro results show that nano-dimpled structure can promote the adhesion and proliferation of mouse cranial anterior bone(MC-3T3-E1) *** filopodia of MC-3T3-E1 cells can be fully extended on this nano-dimpled *** the surface of the nano-dimpled structure with a dimple size of 40 nm, the cells have the longest aspect *** small dimple size of the nanodimpled structure is beneficial to cell proliferation and osteogenic differentiation.

关键词： tantalum Nano-dimpled structure Cell behaviors Anodization

Quasi-In-Situ EBSD Observation of the Orientation Evolution in Polycrystalline tantalum During Rolling Deformation

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2019年第8期32卷 1015-1020页

作者： Ya-Hui Liu Shi-Feng Liu Chao Deng Hai-Yang Fan Qing Liu College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Electron Microscopy Center of Chongqing University Chongqing UniversityChongqing 400044China Department of Mechanical Engineering KU LeuvenLeuvenBelgium

The evolution of crystallographic orientation of polycrystalline tantalum(Ta)during rolling was characterized by electron backscatter diffraction technique in a quasi-in-situ way,and the microstructure and microtexture before and after the deformation were characterized and analyzed,*** the specimen,164 individual grains were exacted singly from the testing region and their corresponding orientations were reconstructed and analyzed,*** show that the heterogeneous deformation in a grain can be reflected by the accidented surface ***,the orientations close to{111}orientations came closer to the{111}corner,while the orientation evolution is more complicated for the orientations close{100}corner,indicating that the evolution of these orientations close to{100}corner seemed to be irregular.

关键词： tantalum Orientation Quasi-in-situ Rolling

Inhomogeneous deformation of {111} grain in cold rolled tantalum

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2018年第11期34卷 2178-2182页

作者： Yahui Liu Shifeng Liu Chao Deng Haiyang Fan Xiaoli Yuan Qing Liu College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Electron Microscopy Center of Chongqing University Chongqing UniversityChongqing 400044China Department of Mechanical Engineering KU LeuvenLeuvenBelgium School of Metallurgy and Material Engineering Chongqing University of Science and TechnologyChongqing 401331China

The microstructures of {111} grain were characterized in detailed and systematically investigated with the aid of electron backscatter diffraction(EBSD) and transmission electron microscope(TEM). The stored energy in different regions in the grain was evaluated by the band contrast values collected from EBSD. The results show that the distribution of energy is inhomogeneous through the grain. Especially,the regions containing the least and the largest energy were extracted from the EBSD data, and then quantitatively analyzed based on the misorientation and Schmid factor. Many peaks with large misorientation appeared in the region containing larger energy, and these peaks represent the existences of micro-bands and micro-shear bands in {111} grain. The results of Schmid factor suggest that the region containing larger energy is prone to deforming ahead of the region with less stored energy, implying the more serious subdivision of the microstructure of region with larger stored energy.

关键词： tantalum Stored energy Misorientation Schmid factor

Preparation of a tantalum-based MoSi_(2)–Mo coating resistant to ultra-high-temperature thermal shock by a new two-step process

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第22期81卷 117-122页

作者： Sainan Liu Hongtai Shen Jiawei Xu Xiaojun Zhou Jianfei Liu Zhenyang Cai Xiaojun Zhao Lairong Xiao School of Materials Science and Engineering Central South UniversityChangshaHunan410083China Center for Mineral Materials School of Minerals Processing and BioengineeringCentral South UniversityChangsha410083HunanChina Key Laboratory of Non-ferrous Metal Materials Science and Engineering Ministry of EducationCentral South UniversityChangsha410083China

To develop an ultra-high-temperature resistant coating for a reusable thermal protection system,the preparation of a tantalum-based MoSi_(2)-Mo coating by a new two-step process of multi-arc ion plating and halide activated pack cementation is *** coating has a dense structure and is well compatible with the tantalum substrate,which can be thermally shocked from room temperature to 1750℃ for 360 cycles without *** mechanism of the coating’s excellent resistance to high-temperature thermal shocks is that a strong-binding gradient interface and a dense SiO_(2) oxide scale with good oxygen resistance are formed by the high-temperature self-diffusion of Si.

关键词： Thermal shock MoSi_(2) tantalum Multi-arc ion plating Pack cementation

Corrosion behavior of tantalum and its nitride in alkali solution

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2003年第4期22卷 276-279页

作者： ZHANGDeyuan LINQin FEIQinyong ZHAOHaomin KANGGuangyu GENGMan R＆DDepartment NationalR＆DCenterforSurfaceEngineeringofChinaShenzhen518029China DepartmentofPhysicalChemistry UniversityofScienceandTechnologyBeijingBeijing100083China

The corrosion behavior of tantalum and its nitrides in stirring NaOHsolutions was researched by potentiostatic method, cyclic voltammetry and XPS. The results showedthat the corrosion products were composed of Ta_2O_5 and NaTaO_3. The corrosion reaction formula oftantalum and its nitrides was written according to cyclic volt-ampere curves. The electric chargetransfer coefficient and the electric charge transfer number were calculated

关键词： surface and interface of materials corrosion electrochemistry tantalum nitride

Plasma-nitriding of tantalum at relatively low temperature

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2004年第2期23卷 185-188页

作者： ZHANGDeyuan LINQin ZHAOHaomin FEIQinyong GENGMan NationalR＆DCenterforSurfaceEngineeringofChina Shenzhen518029China UniversityofScienceandTechnologyBeijing Beijing100083China

The combined quadratic orthogonal regression method of experiment design wasemployed to explore the effects of process parameters of plasma nitriding of tantalum such as totalpressure, temperature and original hydrogen molar fraction on the hardness, roughness and structureof nitriding surfaces. The regression equations of hardness, roughness and structure were givenaccording to the results of regression and statistic analysis. And the diffusion activation energyof nitrogen in tantalum on plasma nitriding conditions was calculated according to the experimentaldata of hardness of plasma-nitriding of tantalum vs time and temperature. The diffusion activationenergy calculated belongs to (155.49 +- 10.51) kJ/mol (783-983 K).

关键词： surface and interface of materials plasma nitriding orthogonal regressionmethod tantalum