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国际医学放射学杂志 2024年第1期 131-132页

作者： f.wang X.f.Zhou R.Q.Chen J.Kang X.Y.Yang J.Z.Lin 彭景

摘要目的比较扫描前使用和不使用对比剂（CA）预负荷时，高翻转角动态磁敏感对比灌注加权成像（DSC-PWI）序列所获得的相对脑血容量（r CBV）和百分比信号恢复（PSR）,

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Assessment of rockburst hazard by quantifying the consequence with plastic strain work and released energy in numerical models

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International Journal of Mining Science and Technology 2019年第1期29卷 93-97页

作者： f.wang R.Kaunda Mining Engineering Department Colorado School of Mines

Quantifying the rockburst consequence is of critical importance to reduce the hazards with preventative measures in underground mines and deep tunnels. Contours of energy components within a pillar model are plotted at different rockmass damage stages, and plastic strain work and released energy are proposed as indicators of rockmass damage consequence. One pillar model under different loading stiffness is simulated to assess indicators of pillar burst and the resulting damages. The results show the rockmass damage under soft loading stiffness has larger magnitude of plastic strain work and released energy than that which is under stiff loading stiffness, indicating the rockburst consequence can be quantified with plastic strain work and released energy in numerical models. With the quantified rockburst consequence,preventative measures can be taken to avoid severe hazards to mine safety.

关键词： Unstable rock failure Rock burst Energy mechanism Numerical modeling Released energy

Toward developing Ti alloys with high fatigue crack growth resistance by additive manufacturing

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Journal of Materials Science & Technology 2023年第1期132卷 166-178页

作者： f.wang L.M.Lei X.fu L.Shi X.M.Luo Z.M.Song G.P.Zhang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China AECC Commercial Aircraft Engine Co. Ltd.Shanghai 201306China

fatigue crack growth behaviors were investigated by three-point bending tests for TA19 alloy fabricated by laser metal deposition and four kinds of heat-treated samples.The crack growth resistance of the TA19 samples in the near-threshold regime and Paris regime was evaluated through the experimental characterization and theoretical analysis of the interaction between fatigue crack andα/βphase inter-face,columnar prior-βgrain boundary and colony boundary.The results show that in the near-threshold regime,the fatigue crack propagation threshold and resistance increase with the increase of widths of lamellarαp phases and colonies,and the decrease of the number ofαlaths with an angle(ϕ)relative to the applied stress direction ranging from 75°to 90°.In the Paris regime,the fatigue cracking path can be deflected at colony boundaries or columnar prior-βgrain boundaries.The larger the deflection angle,the more tortuous the cracking path and the lower the fatigue crack growth rate.The angle(γ)of the columnar prior-βgrain growth direction relative to the build direction affects not onlyϕof differentαvariants,but also the fatigue cracking path deflection angle(θij)at columnar prior-βgrain boundaries.An optimal combination ofγ=0°-15°-0°-15°for several adjacent columnar prior-βgrains is derived from the theoretical analysis,and that can effectively avoidϕbeing in the range from 75°to 90°and makeθij as large as possible.Such findings provide a guide for the selection of scanning strategies and process parameters to additively manufacture Ti alloys with high fatigue damage tolerance.

关键词： Ti alloy fatigue crack growth Additive manufacturing Phase interface Grain boundary

Hardening and toughening effects of intermediate nanosized structures in a confined amorphous alloy film

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Journal of Materials Science & Technology 2022年第23期118卷 44-53页

作者： Z.Q.Chen M.C.Li X.Tong Y.Zhao J.Y.Xie S.W.Guo P.Huang f.wang H.B.Ke B.A.Sun W.H.wang Songshan Lake Materials Laboratory Dongguan 523808China Institute of Physics Chinese Academy of SciencesBeijing 100190China Xinjiang Key Laboratory of Solid State Physics and Devices and School of Physical Science and Technology Xinjiang UniversityXinjiangUrumqi 830046China Key Laboratory of LCR Materials and Devices of Yunnan Province School of Materials and EnergyYunnan UniversityKunming 650091China State-Key Laboratory for Mechanical Behavior of Material Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi’an Jiaotong UniversityXi’an 710049China National Demonstration Center for Experimental Mechanics Education Xi’an Jiaotong UniversityXi’an 710049China

The plastic deformation of amorphous alloys is well known to be localized into shear bands(SBs),which are believed to stem from the atomic-scale flow defects,i.e.,shear transformation zones(STZs).Yet,the bridge between the mesoscopic SBs and the atomic-scale STZs remains poorly understood.In this work,through thermally activating pronouncedβrelaxations in the well-designed crystalline-layer confined amorphous(CLCA)Ni W alloy films,we experimentally captured and observed an intermediate nanosized structure termed as“nano shear bands”(NSBs)with a typical size of 1–2 nm in thickness and5–10 nm in length.The influences of such NSB structures on the macroscale deformation behavior were systematically investigated.It was found that NSBs lead to both hardening and toughening effects for the CLCA films,as they promote multiple and controlled shear banding deformation,which results in enhanced crystallization.The intermediate NSB structure could connect the microstructural characteristics and macroscopic plasticity in amorphous alloys and may provide new insights for understanding the microscopic deformation mechanism of amorphous alloys as well as tuning/designing their properties.

关键词： Amorphous alloys Nano shear band Hardening Toughening Crystallization

IN SITU PROCESSING Of Al_(2)O_(3) WHISKERS REINfORCED Ti-Al INTERMETALLIC COMPOSITES

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Acta Metallurgica Sinica(English Letters) 2006年第6期19卷 432-440页

作者： f.wang Z.K.fan J.f.Zhu School of Materials Science and Engineering Xi’an University of TechnologyXi’an 710048China School of Materials Science and Engineering Shaanxi University of Science and TechnologyXianyang 712081China

In situ Al2O3 whiskers reinforced Ti-Al intermetallic composites were fabricated at ~1200℃ by reaction sintering of cold-consolidated fillets consisting mainly of Ti, Al, and different additives. The phases and microstructures of the sintered composites were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The process of synthesis was investigated using differential thermal analysis (DTA). The effects of processing parameters and additives on the microstructures of the composites and the development of whisker were examined. It is found that the morphology of the whisker is strongly influenced by the additives, the exothermal reaction process, and the processing parameters.

关键词： in situ Al2O3 whisker Ti-Al intermetallic composite additive reaction process

Irradiation-induced homogeneous plasticity in amorphous/amorphous nanolaminates

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Journal of Materials Science & Technology 2020年第22期54卷 70-77页

作者： L.Huang Z.Q.Chen P.Huang X.K.Meng f.wang State Key Laboratory for Mechanical Behavior of Material School of Materials Science and EngineeringXi'an Jiaotong UniversityXi'an710049China Institute of Materials Engineering National Laboratory of Solid State MicrostructuresCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210023China State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi'an Jiaotong UniversityXi'an710049China

Achieving homogeneous plastic deformation in metallic glasses is a long-standing goal yet to be solved in materials science. Here we investigate the effect of ion irradiation on the plastic deformation behavior of ZrCu/ZrCuNiAlSi amorphous/amorphous nanolaminates(A/ANLs) via nanoindentation testing. The experimental results indicate a dramatic change in deformation mode from multiple shear banding events to homogeneous compressive deformation before and after ion irradiation on the A/ANLs in the areas underneath the indenter. Ion irradiation-induced changes of both fraction and distribution of free volume inside each constituent layer and interfacial state in the A/ANLs may be responsible for the unusual homogeneous deformation behavior. Our results suggest that the mechanical property of A/ANLs could be modified by tuning both the inner and interfacial structure via ion irradiation.

关键词： Metallic glasses Ion irradiation Plastic deformation Nanolaminates Interface

Structure and topological transport in Pb-doping topological crystalline insulator SnTe(001)film

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Journal of Materials Science & Technology 2020年第9期44卷 223-228页

作者： C.H.Yan f.Wei Y.Bai f.wang A.Q.Zhang S.Ma W.Liu Z.D.Zhang shenyang national laboratory for materials science institute of metal researchchinese academy of sciencesshenyang 110016china university of chinese academy of sciences beijing 100049china school of materials science and engineering university of science and technology of chinahefei 230026china

Topological crystalline insulator(TCI)as a new type of topological materials has attracted extensive research interests for its tunable topological properties.Due its symmetry topological protection essence,the structure investigation provides a solid basement for tuning its topological transport properties.On SrTiO3(111)substrate,the SnTe film was found to be epitaxial growth only along[001]while not[111]direction.The detailed structural study was performed and a structural model was proposed to elucidate epitaxial growth of the SnTe(001)film.The transport properties of SnTe(001)film were further investigated and a typical weak anti-localization effect was observed.By Pb-doping into SnTe,the bulk carriers were inhibited and its topological surface states were strengthened to induce the enhanced surface transport contribution.With tunable multiple transport channels from the even Dirac cones,the TCI SnTe film systems will have the potential application in future spintronics devices.

关键词： Topological crystalline insulator Surface state SnTe

The mechanical behavior of nanoscale metallic multilayers:A survey

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Acta Mechanica Sinica 2015年第3期31卷 319-337页

作者： Q.Zhou J.Y.Xie f.wang P.Huang K.W.Xu T.J.Lu State-Key Laboratory for Mechanical Behavior of Material Xi’an Jiaotong University State-Key Laboratory for Mechanical Structure Strength and Vibration Xi’an Jiaotong University

The mechanical behavior of nanoscale metallic multilayers （NMMs） has attracted much attention from both scientific and practical views. Compared with their monolithic counterparts, the large number of interfaces existing in the NMMs dictates the unique behavior of this special class of structural composite materials. While there have been a number of reviews on the mechanical mechanism of micro- laminates, the rapid development of nanotechnology brought a pressing need for an overview focusing exclusively on a property-based definition of the NMMs, especially their size- dependent microstructure and mechanical performance. This article attempts to provide a comprehensive and up-to-date review on the microstructure, mechanical property and plas- tic deformation physics of NMMs. We hope this review could accomplish two purposes：（1） introducing the basic concepts of scaling and dimensional analysis to scientists and engi- neers working on NMM systems, and （2） providing a better understanding of interface behavior and the exceptional qual- ities the interfaces in NMMs display at atomic scale.

关键词： Multilayer Interface Microstructure Mechanical behavior

Harmonic injection locking of high-power mid-infrared quantum cascade lasers

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Photonics Research 2021年第6期9卷 1078-1083页

作者： f.wang S.SLIVKEN M.RAZEGHI Center for Quantum Devices Department of Electrical Engineering and Computer ScienceNorthwestern UniversityEvanstonIllinois 60208USA

High-power,high-speed quantum cascade lasers(QCLs)with stable emission in the mid-infrared regime are of great importance for applications in metrology,telecommunication,and fundamental tests of physics.Owing to the intersubband transition,the unique ultrafast gain recovery time of the QCL with picosecond dynamics is expected to overcome the modulation limit of classical semiconductor lasers and bring a revolution for the next generation of ultrahigh-speed optical communication.Therefore,harmonic injection locking,offering the possibility to fast modulate and greatly stabilize the laser emission beyond the rate limited by cavity length,is inherently adapted to QCLs.In this work,we demonstrate for the first time the harmonic injection locking of a mid-infrared QCL with an output power over 1Win continuous-wave operation at 288 K.Compared with an unlocked laser,the intermode spacing fluctuation of an injection-locked QCL can be considerably reduced by a factor above 1×10^(3),which permits the realization of an ultrastable mid-infrared semiconductor laser with high phase coherence and frequency purity.Despite temperature change,this fluctuation can be still stabilized to hertz level by a microwave modulation up to∼18 GHz.These results open up the prospect of the applications of midinfrared QCL technology for frequency comb engineering,metrology,and the next-generation ultrahigh-speed telecommunication.It may also stimulate new schemes for exploring ultrafast mid-infrared pulse generation in QCLs.

关键词： power injection locking

Photoabsorption Spectra of Nano-Crystalline Silicon films

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Chinese Physics Letters 1993年第12期10卷 752-755页

作者： LIU Xiangna HE Yuliang f.wang R.Schwarz Department of Physics and Laboratory of Solid State Microstructuresj Nanjing UniversityNanjing 201800 Department of Physics E16 T.U.MunichFR.Germany

The photoabsorption spectra,of nanoycrystalline silicon(nc-Si:H)films were measured by means of constant photoconductivity method.We investigated the changes of absorption spectra,with the increasing of crystallinity as the deposited films are amorphous,micro crystallin e and nan o-crystallin e.We found that in nc-Si:H the transition processes in the interfacial region between the grains predominate the whole range of the absorption spectra.We related the phenomenon to the structural changes in the material.

关键词： material. spectra. method.