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Microstructures and mechanical properties of Ti3Al/Ni-based superalloy joints brazed with AuNi filler metal

Journal of Materials Science & Technology 2019年第9期35卷 2070-2078页

作者： H.S. Ren H.P.xiong W.M. Long B. Chen y.x. shen J. Pang Welding and Plastic Forming Division Beijing Institutes of Aeronautical MatericalBeijing 100095China State Key Laboratory of Advanced Brazing Filler Metals and Technology Zhengzhou Research Institute of Mechanical EngineeringZhengzhou 450001 China Department of Material Science and Engineering Beihang UniversityBeijing 100191China

For the purpose of high-temperature service and the weight reduction in aviation engineering applications, the dissimilar joining of Ti3Al-based alloy to Ni-based superalloy (GH536) was conducted using Au-17.5Ni (wt%) brazing filler metal. The microstructure and chemical composition at the interfaces were investigated by scanning electron microscope, x-ray diffraction and transmission electron microscope. The diffusion behaviors of elements were analyzed as well. The results indicated that the Ti3Al/GH536 joint microstructure was characterized by multiple layer structures. Element Ni from Au-Ni filler metal reacted with Ti3Al base metal, leading to the formation of AlNi2Ti and NiTi compounds. Element Ni from Ti3Al base metal reacted with Ni and thus Ni3Nb phase was detected in the joint central area. Due to the dissolution of Ni-based superalloy,(Ni,Au) solid solution ((Ni,Au)ss) and Ni-rich phase were visible adjacent to the superalloy side. The average tensile strength of all the joints brazed at 1253 K for 5-20 min was above 356 MPa at room-temperature. In particular, the joints brazed at 1253 K/15 min presented the maximum tensile strength of434 MPa at room-temperature, and the strength of 314 MPa was maintained at 923 K. AlNi2Ti compound resulted in the highest hardness area and the fracture of the samples subjected to the tensile test mainly occurred in this zone.

关键词： Ti3Al-based alloy Ni-based superalloy Brazing Microstructure Tensile strength

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PURIFICATION OF COBALT ANOLyTE USING THE NOVEL SOLVENT ExTRACTION SySTEM

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Acta Metallurgica Sinica(English Letters) 2003年第2期16卷 114-121页

作者： y.F.shen W.y.xue W.y.Niu Jinchuan Non-ferrous Metals Complex Jinchuan 737100ChinaState Key Laboratory of Rolling and AutomationNortheastern UniversityShenyang 110014ChinaState Key Laboratory of Rolling and AutomationNortheastern UniversityShenyang 110014ChinaState Key Laboratory of Rolling and AutomationNortheastern UniversityShenyang 110014China

In present research, a novel extractant system (D2EHPA + naphthenic acid + pyridine- ester) was used to purify cobalt anolyte and a simulated industrial production were carried out. This novel extraction system can extract Cu and/or Ni against Co from chloride medium solutions at pH range of 2.5-4.5. About 2g/l nickel and 0.2g/l copper were removed from the cobalt chloride anolyte containing about 100g/l cobalt and 200g/l chloride ions respectively, the raffinate contains nickel and copper less than 0.03g/l and 0.0003g/l respectively and can be used to electrolyze high-purity cobalt. About 5.5t cobalt anolyte was purified in the simulation industrial experiment and kilogram quantities of cobalt of 99.98% purity and about 95% recovery have been produced.

关键词： solvent extraction nickel cobalt anolyte naphthenic acid pyridine-ester

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Effects of Processing Parameters on Weld Geometries in Electron Beam Welding Based on Partial Correlation Analysis

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稀有金属材料与工程 2011年第S4期40卷 30-34页

作者： shen x F,Huang W R,Zhang y Z Institute of Machinery Manufacturing Technology,China Academy of Engineering Physics,Mianyang 621900,China China Acad Engn Phys Inst Machinery Mfg Technol Mianyang 621900 Peoples R China

Accelerating voltage,electron beam current,welding speed constitutes the main electron beam welding process parameters,while the penetration depth and depth-width ratio are two of the most important characteristic parameters of the weld *** complex interactions exists between the five variables,so the analysis of a single process parameter on one of weld geometries is affected by the other process parameters,and the impact of these interference parameters should be excluded to find the real relationship between the variables where partial correlation analysis provides such a *** of the accelerating voltage,electron beam current,welding speed of electron beam welding process parameters on weld geometries is analyzed by using partial correlation *** priority order of adjustment of process parameters is obtained,namely:in order to obtain a larger depth-width ratio indicators,it should be taken firstly to increase the beam current and accelerating voltage,and then to raise the welding speed;in order to obtain greater penetration depth,it is preferred to increase the beam current,followed by increasing the accelerating voltage,and reducing the welding speed finally.

关键词： electron beam welding process parameters characteristic parameters of weld morphology partial correlation analysis

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Ion motion effects on the generation of short-cycle relativistic laser pulses during radiation pressure acceleration

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High Power Laser Science and Engineering 2014年第2期2卷 1-7页

作者： W.P.Wang x.M.Zhang x.F.Wang x.y.Zhao J.C.xu y.H.yu L.Q.yi y.Shi L.G.Zhang T.J.xu C.Liu Z.K.Pei B.F.shen State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences

The effects of ion motion on the generation of short-cycle relativistic laser pulses during radiation pressure acceleration are investigated by analytical modeling and particle-in-cell simulations. Studies show that the rear part of the transmitted pulse modulated by ion motion is sharper compared with the case of the electron shutter only. In this study, the ions further modulate the short-cycle pulses transmitted. A 3.9 fs laser pulse with an intensity of 1.33×1021W cm-2is generated by properly controlling the motions of the electron and ion in the simulations. The short-cycle laser pulse source proposed can be applied in the generation of single attosecond pulses and electron acceleration in a small bubble regime.

关键词： radiation pressure acceleration short-cycle pulses particle-in-cell simulations.

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Magnetite of Early Ordovician limestone in Tarim and implications for paleomagnetism

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Chinese Science Bulletin 1997年第13期42卷 1110-1113页

作者： shen, Zy ye, y Fang, DJ Department of Earth Sciences Zhejiang University Hangzhou 310027 China

THE Early Ordovician Baiyungang Formation limestone in Tarim is characterized by multiplemagnetic components including primary remanent magnetism (PRM) and late remagnetiza-tion. Considerable attention should be paid to its petromagnetic significance. Investigatingthe relationship between these components and the magnetic carriers is important to distin-

关键词： petromagnetism paleomagnetism Baiyungang Formation.

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Grain refinement mechanism of Mg-3Sn-1Mn-1La alloy during accumulative hot rolling

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Journal of Materials Science & Technology 2021年第32期91卷 251-261页

作者： Z.y.Zhao R.G.Guan y.F.shen P.K.Bai School of Materials Science and Engineering North University of ChinaTaiyuan 030051China bEngineering Research Center of Continuous Extrusion Ministry of EducationDalian Jiaotong UniversityDalian 116028China Key Laboratory for Anisotropy and Texture of Materials Northeastern UniversityShenyang 110004China

We elucidate the effect of lanthanum(La) on the grain refinement of Mg-3 Sn-1 Mn alloy during accumulative hot rolling. The lath-shaped Mg_(2) Sn phase in the Mg-3 Sn-1 Mn alloy is firstly broken and spheroidized,and then the size increases and coarsens with the increase of rolling reduction, most of Mg_(2) Sn move from grain boundary to grain and are homogeneously distributed within the matrix. However, the plate-shaped Mg Sn La compound in Mg-3 Sn-1 Mn-1 La gradually becomes fine, spheroidized, and homogeneously distributed. The grain sizes of Mg-3 Sn-1 Mn and Mg-3 Sn-1 Mn-1 La alloys become fine through dynamic recrystallization(DRx), though the grain refinement of Mg-3 Sn-1 Mn-1 La alloy is better compared to the Mg-3 Sn-1 Mn alloy. A large number of uniformly distributed spherical Mg Sn La compounds pin the dislocations, thus increasing the dislocation density. Hence, the driving force for DRx increases and promotes the formation of deformation bands and more twins, providing the sites for DRx nucleation and growth.

关键词： Mg alloy Grain refinement Dynamic recrystallization Accumulative hot rolling

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Internal Oxidation of Cu-Al Alloy

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Journal of Materials Science & Technology 1999年第5期15卷 444-448页

作者： Wu, JJ Zhang, y shen, yT Li, GB Lei, TQ Hebei Univ Technol Dept Mat Sci & Engn Tianjin 300130 Peoples R China Harbin Inst Technol Sch Mat Sci & Engn Harbin 150006 Peoples R China

The thermodynamics and kinetics of the internal oxidation in dilute Cu-Al alloy are investigated. The internal oxidation of copper alloy containing 0.2 similar to 1.2 wt pet Al is studied in the temperature range from 1073 K to 1273 K. A related equilibrium diagram is drawn. A mathematic model of oxidation layer depth is developed on the base of the experimental results. The experiments and investigation show that the formation rate of the internal oxidation layer is mainly controlled by the diffusion of O in matrix, the O concentration on the surface and the Al concentration in the alloy.

关键词： Copper alloys

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SyNTHESIS AND MICROSTRUCTURE OF SUPERHARD TiN/SiN_x MULTILAyER THIN FILMS

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 242-248页

作者： Z.F.Zhou y.G.shen y.W.Mai K.y.Li AdvancedCoatingsAppliedResearchLaboratory（ACARL） DepartmentofManufacturingEngineeringandEngineeringManagementCityUniversityofHongKongKowloonHongKongChina CentreforAdvancedMaterialsTechnology（CAMT） SchoolofAerospaceMechanicalandElectronicEngineeringUniversityofSydneySydneyNSW2006Australia

Multilayer thin films of TiN/SiNx have been deposited onto heated Si 100 substra tes (200℃) by reactive dc-magnetron sputtering from Ti and Si targets in an Ar- N2 gas mixture. The rotation speed of the substrate holder was varied from 1 to 20rpm, while target currents were held constant, to produce bilayer periods vary ing from approximately 22 to 0.6nm. These multilayer films were characterized by atomic force microscopy (AFM), cross-sectional transmission electron microscopy (TEM), scanning electron microscopy (SEM), and microhardness measurements. TEM and SEM studies showed elimination of columnar structure in TiN, owing to the in corporation of amorphous SiNx layers. The crystallinity of TiN and amorphous nat ure of SiNx were confirmed by high resolution TEM. An optimum rotation speed was observed, at which hardness was a maximum. The resulting bilayer period was fou nd to be approximately 1.6nm, which resulted in a significant improvement in mic rohardness (~57GPa). The rms surface roughness for this film was less than 1.5nm .

关键词： multilayers hardness supermodulu s stress TiN/SiNx

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A novel scheme for ultrashort terahertz pulse generation over a gapless wide spectral range:Raman-resonance-enhanced four-wave mixing

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Light(Science & Applications) 2023年第2期12卷 232-238页

作者： Jiaming Le yudan Su Chuanshan Tian A.H.Kung y.Ron shen Department of Physics State Key Laboratory of Surface Physics and Key Laboratory of Micro-and Nano-Photonic Structure(MOE)Fudan UniversityShanghai 200433China Department of Physics University of CaliforniaBerkeleyCA 94720USA Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

Ultrashort energetic terahertz(THz)pulses have created an exciting new area of research on light interactions with *** material studies in small laboratories,widely tunable femtosecond THz pulses with peak field strength close to MV cm-1 are ***,they can be largely acquired by optical rectification and difference frequency generation in crystals without inversion *** describe in this paper a novel scheme of THz pulse generation with no frequency tuning gap based on Raman-resonance-enhanced four-wave mixing in centrosymmetric media,particularly *** show that we could generate highly stable,few-cycle pulses with near-Gaussian spatial and temporal profiles and carrier frequency tunable from 5 to>2o *** had a stable and controllable carrier-envelop phase and carried~15 nJ energy per pulse at 10 THz(with a peak field strength of~1 MV cm^(-1)at focus)from a O.5-mm-thick *** measured THz pulse characteristics agreed well with theoretical *** merits of the scheme are discussed,including the possibility of improving the THz output energy to a much higher level.

关键词： pulse ultrashort tuning

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Neurovascular unit in diabetic retinopathy:pathophysiological roles and potential therapeutical targets

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Eye and Vision 2021年第3期8卷 135-153页

作者： shen Nian Amy C.y.Lo yajing Mi Kai Ren Di yang Department of Pathology Xi’an Medical UniversityXi’anShaanxi ProvinceChina Department of Ophthalmology LKS Faculty of MedicineThe University of Hong KongHong KongHong Kong Institute of Basic Medicine Science Xi’an Medical UniversityXi’anShaanxi ProvinceChina Department of Biochemistry and Molecular Biology Xi’an Medical UniversityXi’anShaanxi ProvinceChina Department of Ophthalmology First Affiliated Hospital of Kunming Medical UniversityKunming Medical UniversityKunmingYunnan ProvinceChina

Diabetic retinopathy(DR),one of the common complications of diabetes,is the leading cause of visual loss in working-age individuals in many industrialized *** has been traditionally regarded as a purely microvascular disease in the ***,an increasing number of studies have shown that DR is a complex neurovascular disorder that affects not only vascular structure but also neural tissue of the *** of neural retina could precede microvascular abnormalities in the DR,leading to microvascular ***,disruption of interactions among neurons,vascular cells,glia and local immune cells,which collectively form the neurovascular unit,is considered to be associated with the progression of DR early on in the ***,it makes sense to develop new therapeutic strategies to prevent or reverse retinal neurodegeneration,neuroinflammation and impaired cell-cell interactions of the neurovascular unit in early stage ***,we present current perspectives on the pathophysiology of DR as a neurovascular disease,especially at the early *** novel treatments for preventing or reversing neurovascular injuries in DR are discussed as well.

关键词： Diabetic retinopathy Neurovascular unit Neurodegeneration Gliosis Inflammation treatment

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