ISSN 0412-1961
CN 21-1139/TG
Started in 1956

About the Journal

  Current Issue
    , Volume 34 Issue 6 Previous Issue    Next Issue
    For Selected: View Abstracts
    THE BEHMAVIORS OF (1/2)〈110] DISLOCATIONS IN γ-TiAl SINGLE CRYSTALS
    WU Doughai; HU Gengxiang(Department of Materials Science; Shanghai Jiaotong University; Shanghai 200030INUI Haruyuki; YAMAGUCHI Masaharu)(Kyoto University; Faculty of Engineering; Kyoto 606--01; JapanCorrespondent : HU Gengxiang; professor Tel: (O21)62812558; Fax. (021)62820892)
    Acta Metall Sin, 1998, 34 (6): 561-564. 
    Abstract   PDF (1836KB) ( 686 )
    The main deformation mode for [021]-oriented γ-TiAl single crystals in thetemperature range of -196 -1000 ℃ has been identified to be {111}(110] ordinary dislocationslip. At low temperatures, (1/2)(110] ordinary dislocations are mostly parallel to their screworientation or 60° with respect to screw orientation and tend to be arranged in groups. Whilein the anomalous yield temperature range, (1/2)(110] ordinary dislocations are mostly parallelto their screw orientation and are heavily cusped. The number of these cusps increases withincreasing temperature. Above the peak temperature, ordinary dislocations do not exhibit allypreferable orientation and tend to move out of their primary slip plane by climbing.
    References | Related Articles | Metrics
    TEM STUDIES OF GRAIN BOUNDARY BETWEEN MARTENSITE LATHES IN 9Ni STEEL
    MENG Xiangmin; LI Guanglai; ZHANG Futian; WU Yakun(Laboratory of Atomic Imaging of Solids; Institute of Metal Research; The Chinese Academy of Sciences; Shenyang110015)Comspondent: MENG Xiangmin; Tel: (024)3843531-55491; Fax: (024)3891320; E-mail: lais imr ac.cn
    Acta Metall Sin, 1998, 34 (6): 565-570. 
    Abstract   PDF (1919KB) ( 836 )
    By means of HREM, the orientation relationships and the atomic structuresof boundary between adjacent two martensite lathes in 9Ni steel have been studied. Three orientation relationships, [001]α2 /[111]α2 /(110)α1 /(110)α2 and two low--angle grain boundaries of 5.3° and 10.6° between (110)α1 and (110)α2 The semicoherent grain botmdaries are composed of structural ledges and dislocations. It could be explained by using known martensite phase transformation relationships.
    References | Related Articles | Metrics
    IN SITU OBSERVATIONS OF MICROSTRUCTURAL AND MORPHOLOGICCAL CHANGES OF THE REDUCTION PRODUCT OF MAGNETITE IN H_2/Ar GAS MIXTURES
    WANG Yarong; LI Jiguang; ZHAO Guojun; XU Lixian; LI Yintai(School of Materials and Metallurgy; Northeastern University; Shenyang 110006)(School of Sources and Civil Engineering; Northeaster University; Shenyang 110016)Comspondent: LI Yintai; professor ; Tel: (024)3914717 Fax (024)3890559
    Acta Metall Sin, 1998, 34 (6): 571-578. 
    Abstract   PDF (3794KB) ( 633 )
    The microstructural changes occurring on the surface of magnetite samples in H2/Ar gas mixture have been directly recorded using an optical heating stage technique, and the nucleation, growth model and growth rate of iron nuclei under different reduction conditions were discussed. The results show that in the temperature range of 773 -- 1373 K, four kinds of nucleus morphologies and growth models with different characteristics were observed tinder different reduction conditions. Morphology transformation and average growth rate of iron nuclei were found to be closely related to temperature and hydrogen partial pressure.
    References | Related Articles | Metrics
    THREE DIMENSIONAL MORPHOLOGY AND MICROSTRUCTURAL EVOLUTION OF BAINITE
    FANG Hongsheng; BO Xiangzheng; WANG Jiajun; XU Ning(Deperment of Materials Science & Engineering; Tsinghua University; Beijing 100084)Correspondent : BO Xiangzheag Fas:(010)62771160; Tel: (010)62782361;E-mail: fhsdms tsinghua edu .cn
    Acta Metall Sin, 1998, 34 (6): 579-585. 
    Abstract   PDF (3022KB) ( 707 )
    The 3--D morphologies of bainite in steels have been studied by scanning electronmicroscopy (SEM) with high resolution, based on the dual--surface observation. The subplatescomposing uPPer berate sheaf are lath-like while the whole morphology of lower bainite andits subplates are plate--shaped. The subunits in lower bainite seem to be lumpish. There is noobvious difference between upper bainite and lower bainite. Between them elms transient bainite,whose 3--D morphology proves to resemble both opper and lower bainite on some aspects. Themicrostructural evolution of three types of bainite has been interpreted when the sympatheticnucleation ledgewise growth mechanism is employed, and the evolution model has been proposed.
    References | Related Articles | Metrics
    SECONDARY ARM SPACING OF UNDERCOOLED Ni_(50)Cu_(50) ALLOY
    LI Jinfu; LU Yili; YANG Gencang; ZHOU Yaohe(State Key Laboratory of Solidification Processing; Northwestern Polytechnical University; Xi'an 710072)Comspondent: LI Jinfu; associate professor; Fax:(029)8491000 Tel: (029)8492374E-mail: Gencangy nmpu.edu.cn.
    Acta Metall Sin, 1998, 34 (6): 586-590. 
    Abstract   PDF (1402KB) ( 579 )
    The secondary arm spacing of undercooled Ni50Cu50 alloy did not decrease withincreasing undercooling in a simple power law, but there was a abnormal protrusion in theirrelationship in the undercooling range of 40 -- 120 K. This phenomenon was first attributedto the increase of primary dendrite tip radius occurring in the transition from solute diffusioncontrolled dendrite growth at low undercoolings to thermally controlled dendrite growth at highundercoolings. The other cause was the substantial sidebranch coarsing induced by the remeltingwhich was extremely serious in the solidification of undercooled melts.
    References | Related Articles | Metrics
    A DIRECTIONAL COARSENING MECHANISM OF THE γ'-PHASE DURING CREEP OF A SINGLE CRYSTAL NICKEL-BASE SUPERALLOY
    TIAN Sugui ; ZHOU Huihua ; ZHANG Jinghua; YANG Hongcai ; XU Yongbo;HU Zhuangqi ( State Key Laboratory for Fatigue and Fracture of Materials; Institute of Metal Research; The Chinese Academyof Sciences; Shenyang 110015)( Department of Materials Science and Engineering; Northeastern University ; Shenyang 110006)( Department of Materials Science and Engineering; Shenyang Polytechnic University; Shenyang 110023)Correspondent: TIAN Sugui; associate professor Tel: (024)5927399
    Acta Metall Sin, 1998, 34 (6): 591-596. 
    Abstract   PDF (2039KB) ( 495 )
    The microstructures of a [001] single crystal nickel--base superalloy at differentstages of the constant loading tensile creep were observed by means of TEM and SEM, and thechemical compositions of γ and γ' phases were analyzed by EDAX in order to investigate theprocess and mechanism of the directional coarsening of γ' phase. The results showed that themesh--like rafts were formed along the direction normal to the stress axis in a mode of side--planelink in primary creep. The applied stress resulted in the decrease of the coherent strain and theenergy of the γ'/γ interfaces. Thus, the energy released was supposed to be the driving force forthe directional diffusion of elements, leading to the formation of the γ' rafts.
    References | Related Articles | Metrics
    GEOMETRICAL ANALYSIS ON PLASTIC DEFORMATION OF POLYCRYSTALLINE METALS AND THE ROOM TEMPERATURE PLASTICITY OF TOW-PHASE TiAl-BASE ALLOYS
    LIANG Wei; YANG Dezhuang( Centre of Testing and Measuring; Taiyuan University of Technologyl Taiyuan 030024)( Harbin Institute of Technology; Harbin 150001)Comspondent: LIANG Wei; prodessor Tel: (0351)6010610 Fax: (0351)6041237
    Acta Metall Sin, 1998, 34 (6): 597-602. 
    Abstract   PDF (593KB) ( 699 )
    Geometrical analysis on plastic deformation charateristics of polycrystallineaggregates proved that the total length of dislocation lines that cat through a unit volume is ininverse proportion to the grain size under given deformation strains, while the total length ofdislocstion lines emitted per unit area of grain boundary is independent of grain size. Furthermore, the distortion of grain boundaries was proved to be propotion to the grain size. On thisbasis and combined with the analysis on the deformation mechanisms, the relationships betweenroom temperature elongation and grain size of two--phase Toil--base alloys were established asfollows:
    References | Related Articles | Metrics
    MECHANISM FOR THE OCCURRENCE OF SERRATED FLOW IN Al-Li SINGLE CRYSTALS
    TIAN Boohui(Beliing Institute of Aeronautical Materials; Beijing 100095)LI Huanxi; ZHANG Youggang; CHEN Changqi(Beijing University of Aeronautics and Astronautics; Beijing 100083)Corresponent: TIAN Baohui; Tel: (010)62456622-5021 Fax:(010)62456925
    Acta Metall Sin, 1998, 34 (6): 603-608. 
    Abstract   PDF (1406KB) ( 573 )
    Strain rate sensitivity varies in a different mariner in Al-Li single crystalsunder different ageing conditions. Stress drops change irregularly with increasing strain andbear no relation to elapsed time for individual serrations. Stress drops and elapsed time duringserrated flow Primarily distribute within their low values under peak aged condition, comparedwith underaged and overaged states. These behaviors may be explained by sheared σ' particlesinducling serrated flow.
    References | Related Articles | Metrics
    INVESTIGATION OF PRODUCTION OF GRADIENT MATERIAL BY CONTINUOUS CASTING
    ZHANG Weiwen; ZOU Ganfeng; DENG Changning; WEI Xinzhao; XU Linkang;YU Ge)( Department Mechano-Electronic Engineering ; South China University of Technology; Guangzhou 510641)(Guangzhou Yongda Machninery Company; Guangzhou 511443)Correspondent: YU Ge; professor Tel: (020)87114547; E-mail: metrlab scut edu cn
    Acta Metall Sin, 1998, 34 (6): 609-614. 
    Abstract   PDF (1341KB) ( 705 )
    A novel method of producing gradient material by continuous casting usingdouble--stream--pouring technique was proposed. The preparation of Al--Si gradient alloy wascarried cot by self--made double -- st ream -- pouring semi--continuous castingfacilities results show that in the steady state, the flow and the solidification of the outside stream andinside stream can be controlled by changing the parameters, such as casting temperature andvolume ratio of the two streams. Different gradient profile of composition in as--cast structurecan be obtained. The good corresponding relationships among the silicon concentration, theInicrostructure and the mechanical properity of the alloy are obtained.
    References | Related Articles | Metrics
    EMBRITTLEMENT BEHAVIOR OF 7075 ALUMINUM ALLOY IN LIQUID METAL Ga
    LIU Xiaomin; QIAO Lijie; CHU Wuyang(Department of Materials Physics; University of Science and Technology Beijing; Beijing 100083)Coerespondent: LIU Xiaomin; Tel: (010)62332906
    Acta Metall Sin, 1998, 34 (6): 615-620. 
    Abstract   PDF (1934KB) ( 670 )
    The liquid metal--induced embrittlement(LME) of 7075 aluminum alloy byGa was investigated by using modified WOL notched specimen. The results showed that the adsorption of Ga atoms could facilitate localized plastic deformation of the base metal and there was an observable concave plastic zone around the notch tip. Then a microcrack would initiate when the adsorption -- facilit at ed plastic deformation reached to a crit ical condit ion. The threshold stress intensity factor of LME under the applied tensile stress was 1.7 MPa'ml/2. When the specimen was loaded in the opposite direction(the displacement V <0),a microcrack would initiate in the tensile stress zone away from the notch tip. The microcrack would propagate towards tensile stress zone and arrest at compressive stress zone. The nominal threshold stress intensity factor for the inverse loading was 3.5 MPa'm1/2. The fracture surfaces of LME for all the specimens were intergranular.
    References | Related Articles | Metrics
    CHAJRACTERISTICS OF OXIDE FORMED ON THE SURFACE OF Zn-48.48Al-1.65Cu-0.03Mg MELT
    CHEN Yunwi; TU Mingjing(Department of Metal Materials; Sichuan Union University; Chengdu 610065)Correspondent: CHEN Yungui; associate professor Tel.(028)5405701; Fax:(028)5220670
    Acta Metall Sin, 1998, 34 (6): 621-626. 
    Abstract   PDF (546KB) ( 463 )
    The hoe characteristics of the Oxide am on the surface of Zn -- 48. 48Al -- 1. 6 5 Cu 0.03Mg meltl were investigated using X--ray photoelectron spectroscopy (XPS) and X--ray exaction (XRD)etc aam oxide film consists mainly of ZnO, Al2O3 and Zn while a small amount of MgO, MgAl2O4 and Cu also exist in the film. The chides of MgO and MgAl2O4 are obviously concentrated on the surface of the film. In these chides, the phenomenon of an excess of metallic ions is quit evident. In addition, it has been proved that, due to the oxidizing the contents of Zn and Mg in the melt will decrease and that of Al and Cu will increase.
    References | Related Articles | Metrics
    OXIDATION BEHAVIOR OF THE SPUTTERED MICSOCRVSTALLNE CONATINGOF LDZ125 SUPERALLOR AT HIGH-TEMPERAFUS
    ZHANG Jie; LOU Hanyi(State Key Laboratory of Corrosion and Protection ;Institute of and Protection Of Metals; The ChineseAcademy of Sciences ; Shenyang 110015)Correspondent : LOU Hanyi; professor Tel: (024)3915908; Fax: (024)3894149
    Acta Metall Sin, 1998, 34 (6): 627-632. 
    Abstract   PDF (3112KB) ( 506 )
    The microcrystalline LDZ125 coating producted by planar magnetron sputteredtechnique has very fine grain size(less than 100 urn) and homogeneous structure consisting ofγ--Phase, while the cast alloy is composed of 7, 7' and Carbides. The oxalation resistance ofthe ~Crystalline layer was much better than that of the CaSt LDZ125 alloy. The Oalde scalesformed on the cast LDZ125 alloy was composed of AJZO3 with small ~s of Cr, Ti and Nieddes. ~ 500 h Obeation, the colltelit of A12O3 in the chide scales reduce because of its spallation during exposure, and the oalde scale was mainly composed of CrZO3 and TiO2. The chidescale formed on the inicrocrystalline LDZ125 consists of Only o--AJsos which had excellent ad-hesion and did hot spall in the durstion of exposure. The beneficial ears of ndcrocrystallizstionon the O~ion resistance of the superalloy were discussed.
    References | Related Articles | Metrics
    MICROSTRUCTURE,DIFFUSION ACCUMULATION OF HYDROGEN AND CRACKING BEHAVIOR IN THE INTERFACE BETWEEN CLADDING AND BASE METALL
    TENG Qinghai; CHEN Lian; LIU Di;; KE Wei(Institute of Corrosion and Protection of Metal; The Chinese Academy of Sciences; State Key Laboratory forCorrosion and Protection; Shenyang 110015)( Institute of Metal Research; The Chinese Academy of Sciences; Liaoning Key Laboratory for Material andHydrogen; Shenyang 110015)( Institute of Equipmeat;Research Fushun Petrochemical Company; Fushun )(Correspondednt : MENC Qinghai; Tel: (0413)B434819; Tel. (0413)2425835
    Acta Metall Sin, 1998, 34 (6): 633-639. 
    Abstract   PDF (2000KB) ( 554 )
    The relationships among the microstructure, diction accUmulatinn of hydrogen and hydrogen induced crabbing behavinr of the interfaCe were investigated. The eXperimental cults saal that the hydrogen distribution in the interfaCe is corresponding to its ndcrostructure,the behavior of by~n induced cracking may expressed by the theory of molecular hydrogen PreSSure. The paths where hydrogen disbonding cracks nucleated and propagated were classal into four typeS, the disbonding cracks would not penetrate into the base metal.
    References | Related Articles | Metrics
    ELECTROCHEMICAL PERFORMANCES OF M1_(1-x)Ca_x(Ni,Co,Al)_5 HYDROGEN STORAGE ALLOYS
    CHEN Weixiang; LIU Wei; CHEN Yun; PAN Hongge; CHEN Changpin(Department of Materials Science and Engineering; Zhejiang University; Haugzhou 310027)Comspondent: CHEN Weixiang ; post-doctor Tel: (0571)7951406; Fan(0571)7951152
    Acta Metall Sin, 1998, 34 (6): 640-644. 
    Abstract   PDF (453KB) ( 497 )
    The effects of the Ca content in M11-x Ca (Ni, Co,Al) 5 hydrogen storage alloys on the electrochendcal performances of hydride electrodes were investigated. It was found that when the Ca cobment in alloys increased, the electrodes actiVation poverty was approved but their cycling durability deCr~d. At x=0.1, alloy has the most discharge capaCity of 331 mAh.g--'(C/3). MIO.sCaO.,(Ni,Co,AI)s and Mfo.sCaO.:(Ni,Co,AI)s alloys have better high--rate dischargeability at iC and ZC rates. At x <0.3, the plateau pressures of the hydrogen storage alloys increases with increasing x. But the plateau pressure of Mad.6CaO.4(Ni,Co,AI)~ alloy is slight lower than that of Mad.:CaO.3(Ni,Co,AI)5 alloy.
    References | Related Articles | Metrics
    THE COVALENT BOND IN LIQUID Al-Si ALLOY AND EFFECT OF Sr ON THE BOND
    WANG Weimin; BIAN Xiufang ;QIN Jingyu(College of Meterial Science and Technology Shandong University of Technology Jinan 250061)S.LSliusarenko(Institute of metal physics ; Ukraine Academy of Science; Kiev-142; 252142; Ukraine)Correspondent : WANC Weimin; E-mail.. weiminw dms sudt edu cn
    Acta Metall Sin, 1998, 34 (6): 645-649. 
    Abstract   PDF (432KB) ( 582 )
    By using high temperature X--ray dffractometer, the structure factor S(Q),radial distribution function 4 and total coordination number of the liquid Al-Si alloy were presented. Radial distribution function of alloy was decomposed by 5 Gaussian peaks, and the elfed of Sron the alloy's liquid structure was investigated. The result showed that Si--Si covalent bond eAsts in the melt of eutectic and hyper--eutectic alloy and Sr has capability to weaken the coto bond.
    References | Related Articles | Metrics
    AN INVESTIGATUIB ON THE RECOVERY BEHMIORS OF THE LATTICE DISTORTIONS IN AN Ni_3P/Ni NANOPHASE MATERIAL
    SUI Manling(Department of Materials Science and Engineering; Northeastern University; Shenyang 110006)Coerespondent: SUI Manling; Fax:(024)3890488; Tel: (024)3893000-7740; E-mail: misui mail.neu.edu.cn
    Acta Metall Sin, 1998, 34 (6): 650-654. 
    Abstract   PDF (412KB) ( 588 )
    An Ni3P/Ni nanophase material, syathesised by the complete crystallization ofan amorphous Ni--P alloy, has been annealed isothermally at differellt temperatures. Variationsof the lattice parameters of the two nanophases with the annealing temperature/time were detendned by means of quantitative X--ray diffraction measurement. It was found that the latticedistortion of the nanophases was recovered during the annealing treatment, but the recovery behaviors of the two nanophases were obviously different at different annealing temperatures. TheseVariations in the microstructure of the nanophases were interpreted in terms of thermodynamicconsiderations.
    References | Related Articles | Metrics
    STRUCTURE AND MICROTRIBOLOGICAL BEHAVIOR OF TEFLON/ Si_3N_4 MICRO-ASSEMBLING FILM
    WANC Jihui; WANG Liduo; LU Xinchun; WEN Shizhu; LI Hengde( State Key Laboratory of Tribology; Tsinghua University; Beijing 100084)( Department of Chemistry; Hong Kong University of Science and Technology; Hong Kong)Coerespondent: LU Xinchun; associate professor Tel: (010)62783160-806; Fax. (010)62784691;E-mail: xcluntl pim tsinghua edu cn
    Acta Metall Sin, 1998, 34 (6): 655-660. 
    Abstract   PDF (1088KB) ( 721 )
    Micro-assembling Teflon/Si3N4 multi--farer film was synthesized by ion beam alternating sputtering Teflon and Si3N4 ceramic targets. The structure, mechanical and ndcrotribological properties were studied by PHI--5300, FT--IR2000, Xos and atolinc force and frictioll force microscOPe. The results show that the multilayer is consist of crystalline Teflon and amorphous St3N4. The hardness of the multilayer is less than that of St3N4; but the toughness of Teflon/SisN' is greatly approved. This Teflon/Si3N4 multilayer has low friction coefficient and high wear resistance. The friction force of Tellon/ St3N4 film is linear with the load in nano--scale.The worn track will be formed in Teflon film when the load is greater than 70 uN.Keywrods: Teflon, multilayer film, structure, structure ,microtribology
    References | Related Articles | Metrics
    A NEW METHOD ON EVALUATING THE YIELD STRENGTH OF METAL FILMS USING DEPTH-SENSING INDENTATION INSTRUMENT
    MA Dejun; XU Kewei; HE Jiawen(State Key Laboratory for Mechanical Behavior of Materials; Xi'an Jiaotong University Xi'an 710049)Corespondent :HE Jiawen; professor Tel: (029)3268696; For: (029)32379910;E-mail: jwheoritu.edu.cn
    Acta Metall Sin, 1998, 34 (6): 661-666. 
    Abstract   PDF (487KB) ( 682 )
    The fiaite element method of elastoplastic large strain was employed to study the indentation erperhoent of thin metal films on silicon substrate combinatioll by a raid spheriod indenter. The relationship between the hardening index of the film and the charactedstic value of load--displaCement curve, and that among the yield strength, hardening indeX, Youness modulus of the film and the m applied load have been established. Co-cub theSe twoforacteristic s and the maxinunn load given by nanoboedtstion test, the hardening index and po strength of the metal oh can be obtained.
    References | Related Articles | Metrics
    THE EFFECT OF PREFERRED ORIENTATION ON X-RAY STRESS MEASUREMENT
    YU Ligen(State Key Lab. for Powder Metallurgy; Central South University of Technology; Chungsha 410083)HE Jiawen; B. C.Hendrix(State Key Lab. for Mechanical Behavior of Materials; Xi'an Jiaotong University; Xi'an 710049)Correspondent: YU Ligen; Tel: (0731)8826911-3630; Fad: (0731)8825755
    Acta Metall Sin, 1998, 34 (6): 667-672. 
    Abstract   PDF (453KB) ( 814 )
    Based on the boundary conditions for prefer--oriellted polycrystals under loading,a new model for the calculation of X--ray elastic constallts (XEC) for prefer--oriented materials,the weighted Hill model, is proposed. The model is applied to calculate the X--my stress measurement curves of some model materials. In order to check the model, the stresses in electroplated and brush--plated copper films are measured. The experimelltal results have good comparison with the calculated results. This helps to explain the low op angle curVature of the stress measuremellt curve for plasma enhanced chemical vapor deposition (PCVD) TiN films. It is mainly caused by the columnar structure exsisted in the PCVD TiN films. When the stress measurement curve has a linear zone at the high op angle, it is suggested to use the slope of the linear zone for the stress calculation.
    References | Related Articles | Metrics