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Formability enhancement in hot spinning of titanium alloy thin-walled tube via prediction and control of ductile fracture

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Chinese Journal of Aeronautics 2022年第2期35卷 320-331页

作者： Pengfei GAO Chao YU Mingwang fu Lu XING Mei zhan Jing GUO State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of High-Performance Precision Forming Technology and EquipmentSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHung HornKowloonHong Kong 999077China Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China

The damage and fracture in hot spinning of titanium alloy is a very complex process under the combined effects of microstructure evolution and stress *** this study,their dependences on processing parameters were investigated by an integrated FE model considering microstructure and damage evolution,and revealing the effects of microstructure and stress states on damage *** results show that the inner surface of workpiece with the largest voids volume fraction is the place with the greatest potential of *** is mainly attributed to the superposition effects of positive stress triaxiality and the smallest dynamic recrystallization(DRX)fraction andβphase fraction at the inner *** damage degree is decreased gradually with the increase of initial spinning temperature and roller fillet ***,it is first decreased and then increased with the increases of spinning pass and roller feed rate,which can be explained based on the variations ofβphase fraction,DRX fraction,stress state and tensile plastic strain with processing *** addition,the dominant influencing mechanisms were identified and ***,the thickness reduction without defect in the hot spinning of TA15 alloy tube is greatly increased by proposing an optimal processing scheme.

关键词： Control of ductile fracture Dynamic recrystallization Forming limit Hot spinning Titanium alloy tube

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Oxidation Kinetics,Structural Changes and Element Migration during Oxidation Process of Vanadium-titanium Magnetite Ore

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Journal of Iron and Steel Research International 2016年第11期23卷 1160-1167页

作者： feng PAN Qing-shan ZHU zhan DU Hao-yan SUN State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of Sciences(CAS)Beijing 100190China University of Chinese Academy of Sciences Beijing 100039China

The oxidation kinetics, structural changes, and elements migration during the oxidation process of the va- nadium-titanium magnetite （VTM） ore were analyzed. Kinetics analysis indicated that the oxidation process was con- trolled by diffusion control and could be divided into interface diffusion and lattice diffusion with apparent activation energy of 99.69 kJ/mol and 144.08 kJ/mol in the range of 800--1000℃, respectively. The surface structure changed with the oxidization temperature as follows： dense surface→nano sized sheets→submicron particles→molten particles. The compact structure changed into porous one because of the elements migration and enrichment. Both Fe and Ti elements migrated in the opposite direction during the oxidation process. The V etement in the raw ore stably existed in the form of V^5＋ state, some vanadium migrated and occupied the tetrahedral sites of the hematite during the oxidation process.

关键词： vanadium-titanium magnetite ore oxidation kinetics structural change element migration

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Research on Catalytic Properties of Palladium Catalyst Prepared by Biological Reduction Method

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China Petroleum Processing & Petrochemical Technology 2013年第2期15卷 24-30页

作者： zhang feng fu Jiquan School of Materials Science and Engineering Beijing Institute of Fashion Technology

This paper relates to highly dispersed supported Pd/MWCNTs and Fd/a-Al2O3 catalysts prepared by biological reduction method. The physico-chemical properties and the difference in catalytic activity of Pd catalysts prepared by bio- logical reduction method and chemical method, respectively, were investigated using XRD, TEM and specific surface char- acterization methods. The catalytic properties of catalysts were studied through activity evaluation means. The test results showed that the catalysts prepared by biological method were characteristic of small Pd nanoparticle size, good dispersion and low agglomeration, while possessing a high activity and stability in styrene hydrogenation reaction in comparison with catalysts prelgared via the chemical method.

关键词： Pd/MWCNTs Pd/a- Al2O3 biological reduction ginkgo leaf Pd nanoparticles

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Two Special Solutions of the Non-ideal Magnetohydrodynamics

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Chinese Physics Letters 2000年第5期17卷 382-384页

作者： feng Xue-Shang LIU Yong WEI feng-Si YE zhan-Yin Laboratory of Numerical Study for Heliospheric Physics Center for Space Sciences and Applied ResearchChinese Academy of SciencesBeijing 100080

A special transformation is found to solve the Magnetohydrodynamic equations,by which two classes of exactanalytic time-dependent solutions of magnetic annihilation for incompressible magnetic fluid have been *** solutions derived here possesses scaling property with time t as the scale *** find that the currentcan perform the soliton-like behaviour in the case of asymmetric *** relevant evolution characteristics inthe process of magnetic annihilation are also revealed.

关键词： annihilation soliton behaviour

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A hybrid multidimensional Riemann solver to couple self-similar method with MULTV method for complex flows

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Chinese Journal of Aeronautics 2021年第7期34卷 29-38页

作者： feng QU Di SUN Junjie fu Junqiang BAI School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China

Since proposed,the self-similarity variables based genuinely multidimensional Riemann solver is attracting more attentions due to its high resolution in multidimensional complex ***,it needs numerous logical operations in supersonic cases,which limit the method’s applicability in engineering problems *** order to overcome this defect,a hybrid multidimensional Riemann solver,called HMTHS(Hybrid of MulTv and multidimensional HLL scheme based on Self-similar structures),is *** simulates the strongly interacting zone by adopting the MHLLES(Multidimensional Harten-Lax-van Leer-Eifeldt scheme based on Self-similar structures)scheme at subsonic speeds,which is with a high resolution by considering the second moment in the similarity ***,it adopts the MULTV(Multidimensional Toro and Vasquez)scheme,which is with a high resolution in capturing discontinuities,to simulate the flux at supersonic *** numerical experiments,including both one-dimensional cases and twodimensional cases,are ***-dimensional moving contact discontinuity case and sod shock tube case suggest that HMTHS can accurately capture one-dimensional expansion waves,shock waves,and linear contact ***-dimensional cases,such as the double Mach reflection case,the supersonic shock/boundary layer interaction case,the hypersonic flow over the cylinder case,and the hypersonic viscous flow over the double-ellipsoid case,indicate that the HMTHS scheme is with a high resolution in simulating multidimensional complex ***,it is promising to be widely applied in both scholar and engineering areas.

关键词： Complex flows Computational fluid dynamics Multidimensional Riemann solver Self-similar

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Synthesis of MgO-doped ordered mesoporous carbons by Mg^(2+)-tannin coordination for efficient isomerization of glucose to fructose

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Green Energy & Environment 2023年第3期8卷 842-851页

作者： Junyan fu feng Shen Xiaoning Liu Xinhua Qi College of Environmental Science and Engineering Nankai UniversityNo.38Tongyan RoadJinnan DistrictTianjin300350China Agro-Environmental Protection Institute Ministry of Agriculture and Rural AffairsNo.31Fukang RoadNankai DistrictTianjin300191China

In-situ MgO-doped ordered mesoporous carbon(OMC@MgO)was fabricated by formaldehyde-free self-assembly method,in which biomass-derived tannin was used as carbon precursor replacing fossil-based phenolics,Mg^(2+)as both cross-linker and precursor of catalytic *** to~20 wt% MgO could be doped in the carbon skeleton with good dispersion retaining well-ordered mesoporous structures,while more MgO content(35 wt%)led to the failing in the formation of ordered mesoporous *** OMC@MgO possessed a high specific surface area(298.8 m^(2) g^(-1)),uniform pore size distribution(4.8 nm)and small crystallite size of MgO(1.73 nm)due to the confinement effect of ordered mesoporous *** OMC@MgO as the heterogeneous catalyst,a maximum fructose yield of 32.4% with a selectivity up to 81.1%was achieved from glucose in water(90℃,60 min),which is much higher than that obtained using the MgO doped active carbon via conventional post-impregnation method(26.5%yield with 58.3% selectivity).Higher reaction temperature(>90℃)resulted in decrease of selectivity due to the formation of *** designed OMC@MgO displayed tolerant to high initial glucose concentrations(10 wt%)and could remain good recyclability without significant loss of activity for three cycles.

关键词： Glucose Fructose Isomerization Porous carbon Biomass Catalysis

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Microstructure and mechanical properties of Ti-Cu amorphous coating synthesized on pure Cu substrate by mechanical alloying method

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Rare Metals 2020年第10期39卷 1222-1228页

作者： Cheng Chen Xiao-mei feng Yi-fu Shen School of Mechanical and Power Engineering Nanjing Tech UniversityNanjing 211800China College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Mechanical alloying method was applied to fabricate coating with amorphous structure on pure Cu *** microstructure,the phase composition and the mechanical properties including microhardness and wear resistance of the coating were,respectively,characterized and *** results show that the coating is rough but *** has favorable adhesion to the *** coating is made up of an inner composite layer and an outer amorphous *** microhardness and the wear resistance of the pure Cu substrate are improved because of the bilayer *** formation mechanism of the coating was *** as-synthesized coating is considered to be effective to strengthen the surface of pure Cu substrate.

关键词： Coating Amorphous Mechanical alloying Surface reinforcement

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Highly Stereoselective Synthesis of 2,2-Disubstituted Vinylphosphonates via Aryl to Vinyl 1,4-Palladium Migration

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Chinese Journal of Chemistry 2022年第18期40卷 2188-2192页

作者： Yan-Zhen Chen Geng-Yu Bao Xin-Chen zhan Jian-Guo fu Xiao-Ming Ji Shu-Sheng zhang Chen-Guo feng The Research Center of Chiral Drugs Innovation Research Institute of Traditional Chinese MedicineShanghai University of Traditional Chinese MedicineShanghai201203 China

Vinylphosphates play an important role in the fields of synthetic chemistry,pharmaceuticals and material *** is a long-standing challenge to control the geometry of multi-substituted ***,an efficient method for the synthesis of 2,2-disubstituted vinylphosphonates has been *** reaction proceeded via aryl to vinyl 1,4-palladium migration progress,in which two difficulties that the deactivation of palladium catalyst by the coordination of excess secondary phosphine oxide and the competitive cross-coupling to form arylphosphonates are successfully *** judicious selection of phosphine ligand is the key to *** protocol features excellent regio-and stereoselectivitiy,generally excellent reaction yields and broad substrate socpe.

关键词： 1,4-Palladium migration Phosphorylation C-H activation Stereoselectivity Cross-coupling

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Dependence of creep age formability on initial temper of an Al-Zn-Mg-Cu alloy

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Chinese Journal of Aeronautics 2016年第5期29卷 1445-1454页

作者： Lei Chao Yang He Li Heng Shi Nian fu Jin zhan Lihua State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University State Key Laboratory of High Performance Complex Manufacturing School of Mechanical and ElectricalCentral South University

The initial temper of the material may directly affect the whole creep age forming （CAF） process. In terms of creep deformation and stress relaxation, using the constant-stress creep aging and constant-strain stress relaxation aging tests, the relationship between initial temper and CAF formability is investigated for an Al-Zn-Mg-Cu alloy at 165 ℃ for 18 h. Three tempers are selected as the initial tempers in CAF, viz., solution, retrogression and re-solution. The CAF formability of this alloy with initial temper of retrogression is the best, and the creep strain of the retrogression tempered specimen after creep aging of 18 h is about 1.21 and 1.34 times than that of the solution and the re-solution tempered specimens, respectively. The calculated stress exponents of this alloy with three initial tempers range from 7.3 to 9.5, indicating that the CAF of this alloy is mainly controlled by the dislocation creep. The various formability for three initial tempers are attributed to different inhibitions of the transgranular precipitates on the dislocation movement. For the retrogression temper, the initial fine and uniformly distributed precipitates are seriously coarsened after 6 h of CAF, which minimally inhibit the dislocation movement. While, for the re-solution temper, the fine precipitates are re-precipitated in the matrix of the alloy, which observably hinder the dislocation movement and lead to the worst formability.

关键词： AI-Zn-Mg-Cu alloy Creep age forming Formability Initial temper Precipitate

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Whittaker Modules for the Derivation Lie Algebra of Torus with Two Variables

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Acta Mathematica Sinica,English Series 2016年第10期32卷 1177-1188页

作者： Hai feng LIAN Xiu fu zhanG Department of Mathematics Fujian Agriculture and Forestry UniversityFuzhou 350002P.R.China School of Mathematics and Statistics Jiangsu Normal UniversityXuzhou 221116P.R.China

Let L be the derivation Lie algebra of C[t1^±1 , t2^±1 ]. Given a triangle decomposition L = L＋ η ＋ L-, we define a nonsingular Lie algebra homomorphism φ ： L＋ → C and the universal Whittaker L-module We of type φ. We obtain all Whittaker vectors and submodules of We. Moreover, all simple Whittaker L-modules of type φ are determined.

关键词： Whittaker vector Whittaker module simple module derivation Lie algebra

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