材料期刊网

INVESTIGATION ON LCF PROPERTIES OF Ti2Al2 5Zr ALLOY TUBE AND ROD

Z.T.Yu1 , 2) , L.Zhou1) , 2) , J.Deng2) and H.C.Gu1) 1) College of MaterialScience and Engineering , Xi’an Jiaotong University , Xi’an 710049 , China 2) NorthwestInstitute for Nonferrous Metal Research , P. O.Box 51 , Xi’an 710016 , China

金属学报(英文版)

Thelow cyclefatigue( LCF) propertiesof Ti 2 Al 2 5 Zralloytubeand rod specimens weredetermined at R.T. Thestress～strain curve equation under cyclic and monotonicloading andtherelation of totalstrain vsfatiguelife of Ti 2 Al 2 5Zr alloy were established. Theeffectsofstrain ratio R,strain amplitudeεaandspecimenshapeoncyclicdeformingbehavior and fatigueproperties were analyzed . The fatiguefracture features were also discussed ac cording as SEMobservation. The resultsshow , at R = 0 1 ,thecyclicstress straincurvesof Ti 2 Al 2 5Zr alloytube and rodspecimensappear ascyclesoftening. When Ris 1 ,itsrodspecimen behavesascyclesoftening;atlow εavalues; whereasitbehavesascyclehardeningat high εa values. The LCFproperties determined withtubespecimen islower apparentlythanthat withrod one. Thereare muchirregularrecrystallineconvexin LCFfracturesof Ti 2 Al 2 5Zr alloytubeand rodspecimens, and muchsecondarycracks,fatiguestriationsand holes alsoexistamongthem .

关键词: Ti 2 Al 2 5 Zralloy , null , null

THE STUDY ON SYNTHESIS OF ULTRAFINE_α Al_2O_3 BYLOW TEMPERATURE COMBUSTION PROCESS

Z.Q. Wang1 , 2) , T.C. Ma2) , G.W. Liu2) , Y.J. Cai2) and B.L. Lu1) 1) College of Chemical Engineering , Dalian University of Technology , Dalian 116012 , China , 2) Department of Material Science and Engineering , Dalian Institute of LightIndustry , Dalian 116034 , China

金属学报(英文版)

Based on thelow temperaturecombustion synthesisof α Al2 O3 from aluminum nitrate,the effectsofthe additives on the formation and particle properties of α Al2 O3 werestudied by XRDand SEM,theinitialstudy on the manometer α Al2 O3 synthesisby LCSwas done, α Al2 O3 withtheparticlesize50 ～80 NM wasgot under properconditions.

关键词: low temperature combustion synthesis , null , null , null

ASTUDY OF VALENCE OF YTTRIUM IN Y_2O_3 Mo CATHODE

J.S.Wang1 , 2) , M.L.Zhou2) , J.X.Zhang2) , Z.R.Nie2) T.Y.Zuo2) and G.J.Zhang2) 1) State Key Laboratory of Materials Chemistry and Applications , Peking University , Beijing 100871 , China2) Schoolof Materials Science and Engineering , Beijing Polytechnic University , Beijing 100022 , China

金属学报(英文版)

The valenceofelementyttrium of Y2 O3 Mocathode materialhasbeenstudied by usingther mal weight analysis, X ray diffraction analysis, Scanning electron microscopy and X rayphotoelectronspectrum . It hasbeen provedthatyttrium oxidecan bereduced by molybdenum carbide. Thereaction between powdered Y2 O3 and Mo2 Ccan happen at 1173 , and Y2 O3may bereduced to metallicyttrium . Afterthepowder mixtureof Y2 O3 and Mo2 Cwasheat treated at1873 K, Yttrium existsin two kinds of chemicalstate- yttrium of zero valence and yttrium ofthreevalences.

关键词: valence , null , null , null

VALENCE ELECTRON STRUCTURE OF HIGH PROPERTY HIGH SPEED RESISTANCE STEEL AND ITS COMPOSITION DESIGN

Z.L. Li1 , 2) , C.X.Ma2) and Z.L.Liu1) 1) Department of Materials Science and Engineering , Liaoning Institute of Technology , Jinzhou 121001 , China 2) Collage of Science , Northeast University , Shenyang , 110006 , China

金属学报(英文版)

Theempiricalelectrontheory of solidsand molecules( EET) and theimproved TFDtheory wereapplied tocalculatethe phasestructurefactorsand interfaceconjunction factorsofcom mon alloying elementsin high speed impact resistance ( HSIR) steel. According tothese va lenceelectron structure parametersitis deduced thatthe alloying elements of high propertyHSIRsteelshould be Mn, Cr, Ni and Mo. The microscopicstructure ofthesteel with this compositionisthe mixtureof martensite, bainiteand austeniteafter quenching andlow tem peraturetempering.Itspropertiesare:σb = 1750 MPa,σ0 2 = 1460 MPa,δ5 = 12 7 % , AKV(at 40 ℃, cross direction) = 21J, which exceed the requirement of design. For the thick plateof high property HSIRsteel,itissuggestedto add alittleamountof Cu on thebasisofabovecomposition .

关键词: High speed impact resistancesteel , null

THEEFFECTS OF SOLUTION TREATMENT ON NEAR ALPHA HIGH TEMPERATURE TITANIUM ALLOYS

J. Zhang1 , 2) , G.P. Li1) and D. Li1) 1) Institute of Metal Research , The Chinese Academy of Sciences , Shenyang 110015 , China 2) Shenyang University , Shenyang 110044 , China

金属学报(英文版)

omesolution treatmentsfor Ti 5 8 Al 4 8Sn 2 0Zr 1 0 Mo 0 34Si 0 90 Nd (1 # alloy) , Ti 6 3 Al 4 8 Sn 2 0 Zr 1 0 Mo 0 34 Si 0 90 Nd(2 # alloy) and Ti 6 8 Al 4 8Sn 2 0 Zr 0 5 Mo 0 34 Si 0 70 Nb 0 90 Nd (3 # alloy) several near alpha Titanium alloysat various temperaturesin (α+ β) two phaseregion havebeen carriedout. Theeffectsofsolution treat menttemperatureon theshape,size, distribution andvolumefraction ofthe primary alpha phase(αprim)havebeeninvestigated. Theresultsshowed thattheshape ofαprim did not depend onthesolution temperature, butthesize, the distribution and the volume fraction changed withthevariedsolutiontreatmenttemperature. Theprimaryalpha phaseprincipally precip itated atthe βgrain boundary regions atthe higher temperature nearthe Tα+ β/ β, and asthe temperature was dropped, αprim precipitated in a more uniform way. By energy spectrumanalysisof SEM, the elemental distributionsin primary αphase and transformed βphase(βtrans) havebeeninvestigated. The resultsshowed thatthe amount of Alelementin αprim is higherobviouslythanin βtransathighertemperature. Asthesolution temperature gotdropped theconcentrationsof aluminum elementgot moreuniform in both αprim and βtrans. Thehigher concentration of aluminum elementin αprim would play a importantrolein orderedα2 phase precipitation, and so have an importanteffecton the high temperature properties of the al loys.

关键词: titanium alloy , null , null

COMPUTER SIMULATION OF EARLY STAGE OF DISLOCATION STRUCTURES IN A FATIGUED COPPER SINGLE CRYSTAL

J.H.Yang1 , 2) , S.X.Li1)and C.X.Ma2) 1) State Key Laboratoryfor Fatigueand Fracture of Materials , Instituteof Metal Research , The Chinese Academy of Sciences , 72 Wenhua Road , Shenyang 110015 , China 2) Department of Materials Physics , Northeastern University , Shenyang 110006 , China

金属学报(英文版)

The dislocation evolution wassimulated by using positiveand negative parallelstraightedgedislocationsrandomly distributing on the primary slip planes astheinitialconditions. Thevein and wallstructuresof dynamicequilibrium have been obtained. Abig dipolestructure wasfound inthesimulation.

关键词: computersimulation , null , null , null

MICROSTRUCTURE AND FORMATION MECHANISM OF LASER CLAD Ni60ACOATING

C.Z. Chen1 , 2) , T.Q. Lei2) , D.W. Cui1)and J.H. Yu1) 1) College of MaterialScience and Technology , Shandong University of Technology , Jinan 250061 , China2) College of MaterialScience and Technology , Harbin Institute of Technology , Harbin 150001 , China

金属学报(英文版)

The microstructure and formation mechanism of laser clad Ni60 Acoating were studied by meansof XRD, SEM, TEMand EDAXetc. Theresultsshow thatthe microstructureofthe coatingiscontrolled bytheratiooftemperature gradient Gand solidification speed υ( G/υ)atthesolid liquidinterface. Attheinterfaceof molten pool/substrate, G/υisquitelarge,and Ni basedsolid solutionsgrowingintheform oflow speed planar grain boundary form abonding belt. With the advancement of the solid liquid interface, G/υdecreases, and a bonding zone mainly composed ofcomplex cellulareutecticsof Ni+ M23( CB)6 and Ni+ Ni3Bisformed when G/υisstilllargeenough. Further decrease willlead to a clad layerthat exhibitscellular and dendritic Ni basedsolidsolutions,dendriticor discontinuousnetwork M7( CB)3 and complex eutectics( Ni+ M23( CB)6 and Ni+ Ni3 B) between them .

关键词: microstructure , null , null , null

Thermodynamic investigation on the BaB2O4-BaF2-2NaF-Na2B2O4 reciprocal system

Journal of Solid State Chemistry

The BaB2O4-BaF2-2NaF-NaB2O4 reciprocal system has been investigated by combination of experimental measurements with theoretical calculation. The Na2B2O4-2NaF binary and Na2B2O4-BaF2 pseudo-binary phase diagrams are measured by means of DTA and X-ray diffraction. The thermodynamic functions for all sub-binary systems are derived from measured phase diagrams and thermodynamic data by CAL-PHAD technique, and the sub-binary phase diagrams are calculated according to phase equilibrium principle. Then, the thermodynamic functions for sub-binary systems are extrapolated to the BaB2O4-BaF2-2NaF-Na2B2O4 reciprocal system, and the phase diagram of the reciprocal system is calculated. The calculated phase diagrams are verified by additional experiments. (C) 1996 Academic Press, Inc.

关键词: phase-equilibrium;beta-bab2o4;crystal

MECHANISMS OF α_2→α_2/γ PHASE TRANSFORMATION IN A TiAL ALLOY

XU Qiang , LEI Changhui (BeiJing Laboratory of Electron Microscopy. Chinese Academy of Sciences , P. O. Box 2724.100080 )Beijing , China.ZHANG Yonggang (Department of Materials Science and Engineering , BeiJing University of Aeronautics and Astronautics , 100083 Beijing , China.)

金属学报(英文版)

A Ti-45at.%Al alloy which was solution-treated at 1350℃ for 30 minutes and quenched in water is employed to explore mechanisms of α_2→γphase transformation. The ageing process of the quenched alloy has been in situ studied it has been found that the γ lamellae can precipitate in the α_2 matrix by two mechanisms. When The alloy is aged at 700℃, the stacking faults pre-existing in the α_2 matrix start to grow and more are generated.With the increase of ageing time and ageing temperature the density of stacking faults is increased and the γ lamellae then precipitate. This isα diffusion-controlled process. Alternatively, the γ lamellae may be formed from the α_2 matrix by 1/3(1100) shearing on the (0001) plane. The latter mechanism implies that the strain-induced transformation may occur, which is confirmed by deformation of the quenched alloy.

关键词: : TiAl , null , null

铝基体β-PbO2-WC-TiO2-CeO2-ZrO2-SnO2电沉积层的工艺优选

刘建华 , 陈步明 , 郭忠诚 , 石小钊 , 徐瑞东

材料保护

为了探讨铝基体电沉积β-PbO2复合层的合适工艺，采用正交试验对电沉积β-PbO2-WC-TiO2-CeO2-ZrO2-SnO2复合层的工艺条件进行了优选，以镀层的表面形貌指数、锌沉积阳极槽电压为指标，确定了其最佳参数：4g／LSnO2，0g／LCeO2，4g／LWC，2g／LZrO2，2g／L TiO2；沉积时间4h，温度50℃，pH值1．5，阳极电流密度3A／dm2。结果表明：以最佳工艺沉积的β-PbO2复合层作锌电积阳极，寿命比α-PbO2镀层的长。

关键词: 电沉积 , β-PbO2复合镀层 , 正交试验 , 最佳工艺 , 铝基体