L(?) Manqi State Key Laboratory of Rapidly Solidified and Non-Equilibrium Alloys
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International Centre for Meterials Physics
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Institute of Metal Research
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Academia Sinica
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Shenyang
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ChinaWAGENDRISTEL A Iastitut fur Anwend Physik
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Technische Universitat in Wien
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Austria associate professor
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Institute of Metal Research
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Academia Sinica
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Shenyang 110015
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China
金属学报(英文版)
The room temperature stability and crystallization of amorphous Nd_xFe_(1-x)thin films with x=0.06—0.90,prepared by flash evaporation at 77 K,were investigated by X-ray diffraction and TEM observation.The amorphous Nd_xFe_(1-x)films are stable at room temperature when 0.19metal Nd,but no NdFe2,a phase expected to occur by phase diagram.
关键词:
amorphous film
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SUN Dongsheng LI Fengzhao Shandong Polytechnic University
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Jinan
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Laboratory of Atomic Imaging of Solids
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Institute of Metal Research
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Academia Sinica
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Shenyang
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ChinaDAI Jiyan LI Douxing Laboratory of Atomic Imaging of Solids
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Institute of Metal Research
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Academia Sinica
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Shenyang
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China associate professor
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Institute of Materials Engineering
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Shandong Polytechnic University
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Jinan 250014
,
China
金属学报(英文版)
Observation under high resolution electron microscope shows that the continuous bombing of high speed ions produces a great amount of vacant site defects.The assembly of vacancies forms vacant dish,and the collapase of vacant dish forms stacking fault tetrahedrons and oth- er crystal defects.The interfaces between phase ε(Fe_(2-3)N)and phase γ'(Fe_4N)are smooth, straight and coherent,and they have the orientation relationships of(11)//(0001)and [110]/[110] .
关键词:
crystal defect
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SUN Xiukui CHEN Wenxiu XU Jian FAN Xueshu WEI Wenduo State Key Laboratory of Rapidly Solidified Non-Equilibrium Alloys
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Institute of Metal Research
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Academia Sinica
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Shenyang
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ChinaWU Yukun PENG Yingguo Laboratory of Atomic Imaging of Solids
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Institute of Metal Research
,
Academia Sinica
,
Shenyang
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China Associate Professor
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The crystal habit,crystalline structure,surface condition and composition of the ultrafine Al particles prepared by inert gas evaporation method were studied in detail by means of high resolution transmission electron microscope,X-ray diffraction and X-ray photo-electron spectrum.The results indicate that the ultrafine Al particles prepared in high pure inert gas are of clear crystal habits,single crystal in a large majority and fcc crystalline structure with a_0=0.405 nm.It is also found on the surface of the Al particles that there is a layer of amor- phous Al_2O_3 with 2 nm average thickness,which could protect the particles against oxidizing further.Therefore,the ultrafine Al particles prepared by the inert gas evaporation method are very stable in atmosphere.
关键词:
ultrafine Al particle
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LI Douxing PING Dehai NING Xiaoguang YE Hengqiang Laboratory of Atomic Imaging of Solids
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Institute of Metal Research
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Academia Sinica
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Shenyang.China Professor
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Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The characteristic of interface depending on the atomic structure exerts an inportant,and sometime controlling,influence on performance of the interacial materials. The present paper reviews the main studies on fine structure of both the materials inter- faces and interfacial reaction products in semiconductor uperlattice,metal multilayer ceram- ics and composite materials by mean of selected area electron doffraction patterns and high resolution electron microscopy. The following features of interfaces are reviewed:the orientation relationships;the char- acteristic of steps,facets and ronghness of interfaces;atomic bonding across the interface;the degree of coherency,the structure of misfit dislocations and elastic relaxations at the inter- faces:the presence of defects at the onterfaces:the structure of the interfacial reaction prod- ucts as well as the reaction kinetics and reaetion mechanism.
关键词:
fine structure of the interfaces
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ZHANG Dawei YU Weicheng WANG Zhongguang National Laboratory for Fatigue and Fracture of Materials
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Institute of Metal Research
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Academia Sinica
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Shenyang
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China Associate Professor
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Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
110015
金属学报(英文版)
Carbon ions with a dose of 3×10~(17) ions/cm~2 was implanted into Ti-6Al-4V alloy at an energy of 80 keV.A 28% increase in edurance limit was found with implantation under stress-controlled fatigue tests(R=O).The surface microstructure changes induced by ion implantation were identified using transmission electron microscopy(TEM).The feature of the fracture surface were observed on scanning electron microscope(SEM).The distribution profile of the implanted ions was measured by secondary ion mass spectroscopy(SIMS).The implanted surface layers contain a high density of irradiation defects and fine TiC precipitates.Subsurface crack origins were found in specimens either with or without implantation.The implanted species diffuse into matrix metal under the action of cyclic load- ing.A possible reason and mechanism for improving fatigue lifetime are also discussed.
关键词:
surface modification
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WANG Zhongguang SUN Zhengming YU Weicheng ** State Key Laboratory for Fatigue and Fracture of Materials
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Institute of Metal Research
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Academia Sinica
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Shenyang.110015
,
China+ To whom correspondence should be addressed
材料科学技术（英文）
Based mainly on the work done at the authors' laboratory in recent years,this paper examines what is currently known about the cyclic deformation and fatigue properties of metal matrix composites, with particular emphasis on discontinuous fiber (whisker or particulate)-reinforced Al composites. The following items are discussed:fatigue strength and life,cyclic deformation and microstructural evolution,microcrack initiation and growth,fatigue crack propagation behaviour.
关键词:
metal matrix composite
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XIA Yuebo ZHANG Tianyi State Key Laboratory for Fatigue and Fracture of Materials
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Institute of Metal Research
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Academia Sinica
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Shenyang
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ChinaFEI Guangtao ZHOU Xing Laboratory of Internal Friction and Defects in Solids
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Institute of Solid State Physics
,
Academia Sinica
,
Hefei
,
China Associate Professor
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The variation of cyclic stress,internal friction and ultrasonic attenuation during cyclic deformation and relations among them have been investigated with different slip orientation Al single crystals.The results indicate that the value of cyclic stress σ,internal friction Q~(-1)and ultrasonic attenuation △α depend obviously on the slip orientation.There are large differences in above three parameters for different slip orientation Al crystals.In early stage of fatigue life,σ and △α increase and Q~(-1)decreases with cycles N,and △α reached maxi- mum before σ,while Q~(-1)and σ get the valley and the peak,respectively,at same cycles.
关键词:
crystal orientation
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FENG Zhongchao GUO Liang LIANG Yong HAN Jian HOU Wanliang NING Xiaoguang Institute of Metal Research
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Academia Sinica
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Shenyang
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China Associate Professor
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
A superhard α-Si_3N_4 film,deposited on metal substrate,was produced by laser chemical vapor deposition adopting a kW-level high power CO_2 laser.Most films are composed of fine Si_3N_4 partieles.They join the metal substrate in strong bond.The films have super hardness,excellent resistance to wear and corrosion,etc.Their thickness may be controlled within 5-30 μm.
关键词:
laser chemical vapour deposition
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LIU Yulin ZHANG Yun ZHAO Hong'en HU Zhuangqi SHI Changxu Institute of Metal Research
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Academia Sinica
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Shenyang
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China Associate Professor
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Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The solid-liquid interface morphology and solute segregation behaviour of AI-Li alloy 8090 during unidirectional solidification were studied by the liquid metal quenehing method under varied processing conditions.When solidification rate,RO.75 mm/min (temper- ature gradient,G_L=130℃/cm),the structure revealed of planar or dendritic interface respectively.With the increase of R,the interface morphology becomes cellular from planar gradually,within a narrow range.And the greater the R,the,finer the dendrite.Segregation of element Cu and impurity elements Fe and Si are quite severe,the interface morphology markedly influences on solute segregation.During solidification at coarse dendrite interface, their segregation ratios are rather great and solidified structure is coarse.
关键词:
Al-Li alloy
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ZENG Xianghua
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SHA Jiande
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SU Ge Institute of Metal Research
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Academia Sinica
,
Shenyang
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ChinaYUAN Jigang LIU Fumei ZHONG Huiwen Southwest Aluminium Mill
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China National Nonferrous Metals Industry Corporation
,
Chongqing
,
China SHA Jiande
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Engineer
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China
金属学报(英文版)
The end grain attack of LDIOCS aluminium alloy plates during chemical milling in hot aqueous solution of sodium hydroxide has been studied.The results show that the microsegregation of some components,i.e.Cu,Si etc.,is the main reason of the end grain at- tack,and it is affected by the conditions of heat treatment as well.The end grain attack significantly diminishes while some technical measures which are beneficial to the reduce of segregation were taken during melting and casting.
关键词:
aluminium alloy
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