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

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    , Volume 26 Issue 6 Previous Issue    Next Issue
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    LEDGE STRUCTURE AT BROAD FACES OF FERRITE PLATES IN LOWER BAINITE
    JIN Qiang;FANG Hongsheng;CAO Jianjun;ZHENG Yankang;CHEN Xiuyun Tsinghua University; Beijing
    Acta Metall Sin, 1990, 26 (6): 5-9. 
    Abstract   PDF (1686KB) ( 728 )
    The ferrite/austenite interfacial structure in lower bainite has beenstudied in a hypereutectoid steel by means of electron microscopy. It is found thatmobile growth ledges and superledges and their three-dimensional morphologies existat the broad faces of ferrite plates in lower bainite, and that growth ledges can alsoevolve from structural ledges. These provide evidence to the ledge growth mechanismof lower bainite.
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    EFFECT OF AUSTENITE DEFORMATION ON ISOTHERMAL NUCLEATION INCUBATION TIME OF PRO-EUTECTOID FERRITE
    LI Jian;SUN Fuyu Central Iron and Steel Research Institute; Ministry of Metallurgical Industry; Beijing
    Acta Metall Sin, 1990, 26 (6): 10-14. 
    Abstract   PDF (413KB) ( 699 )
    A calculation method for the isothermal nucleation incubation timeof pre-eutectoid ferrite from deformed austenite has been developed by introducingFeder's incubation time expression into the decomposition of dsformed austenite.The effects of austenite deformation stored enerey and austenite grain boundary en-ergy change on the incubation time have been theoretically calculated. The calcula-ted result seems to be consistent with a rule of experimental data that the austenitedeformation stored energy and the change of austenite grain boundary energy arethe nature of austenite deformation affecting upon the ferrite nucleation.
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    AS-CAST STRUCTURE OF Fe-Mo-C ALLOY
    DING Peidao;SHI Gongqi;ZHOU Shouze Chongqing University
    Acta Metall Sin, 1990, 26 (6): 15-18. 
    Abstract   PDF (935KB) ( 594 )
    The structure and morphology of as-cast Fe-13wt-%Mo-0.8wt-%Calloy have been observed under SEM and TEM. Few δ-eutectoid but certain minoreutectic appeared in the core of dendrites of the alloy. The eutectic carbide is foundas skeleton M_6C while the eutectoid carbide as rodlet M_6C.
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    MICROSTRUCTURAL FEATURE IN Al-In MONOTECTIC ALLOY PROCESSED UNDER MICROGRAVITY
    HUANG Zheng;ZHAO Deqian;CHEN Xichen Beijing University of Aeronautics and Astronautics Institute of Physics; Academia Sinica; Beijing
    Acta Metall Sin, 1990, 26 (6): 19-23. 
    Abstract   PDF (1376KB) ( 721 )
    The microstructural feature of Al-In monotectic alloy processed undermicrogravity has been investigated in comparison between space and ground-basedsamples. It was found that in the space sample, there are a lot of In particles inAl dendrite, but no more in the ground-based one. Moreover, the In particles dis-tribute with regularity and the Al dendrite has an obvious boundary layer markedby a string of particles. Thus, the distinction between them may reflect the chara-cteristics of the solid/liquid interface during solidification under different gravityconditions.
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    METASTABLE R PHASE IN Fe-Cr-Mo AND Fe-Cr-W ALLOYS
    LIU Shicheng;HAMAGOCHI Yoshikazu;KUWANO Hisashi Dalian Railway Institute Muroran Institute of Technology; Japan
    Acta Metall Sin, 1990, 26 (6): 24-28. 
    Abstract   PDF (1129KB) ( 681 )
    The precipitation behaviour of Fe-Cr-Mo and Fe-Cr-W alloys duringaging has been experimentally studied. It was found that in the early stage of ag-ing, a metastable R phase precipitated in both Fe-Cr-Mo and Fe-Cr-W alloys,which transformed to stable μ-phase, Laves-phase, X-phase or σ-phase in the laterstage. The crystallographic structure of metastable R phase is rhombohedral withlattice parameters α=0.9075nm, α=74.45°. The chemical composition of metastableR phase is Fe-(27.5--34.9)Mo-(0--25.5)Cr and Fe--(28.9--33.0)W--(9.36--21.0) Crin at.-% in Fe-Cr-Mo and Fe-Cr-W system, respectively.
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    EFFECT OF HYDROGEN ON DEBYE TEMPERATURE AND LATTICE PARAMETER OF TITANIUM ALLOY
    YU Bingxi;GAO Shujun Institute of Metal Research; Academia Sinica; Shenyang
    Acta Metall Sin, 1990, 26 (6): 29-33. 
    Abstract   PDF (367KB) ( 660 )
    The variations of Debye temperature and lattice parameter of a Ti-30Mo alloy with different hydrogen contents have been measured by means of X-raydiffraction. It was found that as the hydrogen content increases, the Debye tempe-rature decreases, but the lattice parameter of the alloy is increased. The above res-ults support experimentally the decohesion theory that hydrogen in metals willweaken the cohesive force between the atoms and make metals brittle.
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    MORPHOLOGY AND CRYSTALLOGRAPHY OF ALLOY NITRIDES IN DIFFUSIONAL NITRIDED LAYER OF 4Cr5MoVlSi STEEL
    LUO Chengping;ZHAO Fang South China University of Technology; Guangzhou
    Acta Metall Sin, 1990, 26 (6): 34-39. 
    Abstract   PDF (1830KB) ( 825 )
    A TEM investigation was made of the morphology, orientation rela-tionship and habit plane of three kinds of alloy nitrides, namely CrN, VN andMo_2N, formed simultaneously in the diffusional nitrided layer of a 4Cr5MoV1Si(H13) steel nitrided at 580℃. It was found that the nitrides were precipitated bycontinuous clustering and subsequent ordering of both interstitial (N) and substitu-tional (Cr, V, Mo) solutes on {001} habit plane. The observed morphology andcrystallography of the nitrides are in good agreement with the predictions from theinvariant line strain model proposed for precipitation transformations.
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    EFFECTS OF RARE EARTH ELEMENTS ON MICROSTRUCTURAL TRANSFORMATION OF LOW OR MEDIUM CARBON Si-Mn-V STEELS DURING QUENCHING AND TEMPERING
    WANG Xiaotian;YAO Yinliang;SHAO Tanhua Xi'an Jiaotong University
    Acta Metall Sin, 1990, 26 (6): 40-45. 
    Abstract   PDF (1980KB) ( 577 )
    The microstructural transformation of four different low or mediumcarbon steels: 20SiMn2V, 20SiMn2VRE, 40SiMn2V and 40SiMn2VRE, during quen-ching and tempering have been examined by TEM, X--ray diffraction and dilatometer.It was shown that the rare earth elements added may make not only the fine aus-tenite grains of the low or medium carbon steels, but also the fine packet of lathmartensite and lath size, lower the M_s temperature and raise the relative Percenta-ge of dislocation substructure of martensite in medium carbon steel, but influenceno more the volume fraction and thermal stability of retained austenite within que-nching and tempering structure of low or medium carbon steels. The rare earthelements may remarkably inhibit the decomposition of low carbon martensite duringlow temperature tempering, retard the precipitation of cementite plates in lath gra-ins and delay the spheroidization of carbides. They may also restrain obviously theprecipitation and spheroidization of cementite in medium carbon martensite duringhigh temperature tempering.
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    MICROSTRUCTURE AND MECHANICAL PROPERTIES OF A Ni-Fe-Co BASE SUPERALLOY AFTER LONG-TERM AGING AT 650℃
    WANG Shuhe;GUO Jianting;LAI Wanhui;GE Yunlong;TAN Minghui;LI Hui Institute of Metal Reseorch; Academia Sinica; Shenyang
    Acta Metall Sin, 1990, 26 (6): 46-51. 
    Abstract   PDF (1855KB) ( 526 )
    The microstructure and mechanical properties of a Ni--Fe--Co base su-peralloy with low thermal expansion coefficient after aging at 650℃ for 200, 500,1000 and 2000h have been investigated. It was found that they are stable at650℃. This alloy is believed to fill the requirements for long time service to aircraftengine.
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    MICROSTRUCTURE AND SOLIDIFICATION CHARACTERISTICS OF M91 CAST Ni-BASE SUPERALLOY
    ZHANG Bingda;TONG Yingjie;ZHANG Jiayuan;LIU Zezhou;ZHU Yaoxiao Institute of Metal Research; Academia Sinica; Shenyang
    Acta Metall Sin, 1990, 26 (6): 52-56. 
    Abstract   PDF (2088KB) ( 588 )
    In comparison with conventional superalloys, no carbide but signifi-cant γ+M_3B_2 and γ+γ' eutecties were revealed to precipitate in the stable as-caststructure of M91 cast Ni--base superalloy which is abundant in B and minified inC. During solidification of the superalloy, the residual liquid is much less and thetendency to porousness is inconsiderable. This superalloy seems to be available forturbine blade and other integral casting under medium temperature and long--termservices.
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    ON THE ORDERING TRANSFORMATIONS IN Ti_3 Al-Nb ALLOY
    LI Dong;ZHOU Jing;CHANG Xin;GUAN Shaoxuan Institute of Metal Research; Academia Sinica; Shenyang
    Acta Metall Sin, 1990, 26 (6): 57-62. 
    Abstract   PDF (2129KB) ( 523 )
    Study was made of the behaviour of ordering transformation in Ti_3Al-Nb alloy, including the ordering at high temperature, the transformation of hightemperature β phase during cooling, and the decomposition of metastable β phaseduring aging. Results show that the ordered primary a_2 and high temperature β inalloy occurred at 1060℃. The transformation of high temperature β phase proceedby β→a_2+ω type during cooling, and the decomposition of metastable β and ωtype proceeded by (β+ω type)_(metastable)→(a_2+β)_(stable) during aging at 700℃.
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    DYNAMIC FRACTURE TOUGHNESS OF ULTRA-STRENGTH STEELS FOR AIRCRAFT USE
    XU Changgan;ZENG Zhongping Beijing University of Aeronautics and Astronautics
    Acta Metall Sin, 1990, 26 (6): 63-67. 
    Abstract   PDF (376KB) ( 812 )
    The plot of load vs deflection (P--D) for two ultrastrength steels30CrMnSiNi2A and 300M has been examined on the Charpy machine impact tester withdigital memory and microcomputer. A criterion was found to availably represent thedynamic fracture toughness, K_(Ic)~D, of the steels under impact loading. The K_(Ic)~D can becalculated with suggesting that the discontinous shape point of the compliance onthe P--D plot is the point of destabilized crack propagation. The K_(Ic)~D of 300M steel,quenched at 870℃ and separately tempered at 300 and 450℃, was estimated to be50--70 and 54--67 MN/m~(3/2) respectively. It seems to be available, with accuracy abo-ut 20%, to the engineering evaluation.
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    EFFECTS OF CRITICAL HYDROGEN CONCENTRATION AND STRESS ON HYDROGEN-INDUCED CRACKING IN PLAIN STEEL 20
    ZHANG Boyu;DIAO Fengqiong;TANG Xiangyun Tsinghua University
    Acta Metall Sin, 1990, 26 (6): 68-74. 
    Abstract   PDF (750KB) ( 620 )
    The theoretical model to calculating critical hydrogen concentration wasreviewed using Devanathen's hydrogen permeation method. The distribution of hydro-gen coneentration along the direction of hydrogen permeation and the critical hydro-gen concentration during hydrogen--induced crack growing, mainly along MnS inclu-sion interfaces, in the hardened and tempered steel 20 have been determined. The al-lied problems were also discussed briefly.
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    INTERACTION BETWEEN PRECIPITATED V_4C_3 PARTICLES AND DEFORMATION TWIN
    XIE Changsheng Huazhong University of Science and Technology; Wuhan
    Acta Metall Sin, 1990, 26 (6): 75-77. 
    Abstract   PDF (911KB) ( 467 )
    The interfacial cornelation between the precipitated V_4C_3 particles and matrix γ-phase as well as the retarding effect of V_4C_3 particles on the development of deformationtwin have been investigated by using Moire pattern of double diffraction of V_4C_3 and γ-phase.The twinning dislocation may be transformed into interfacial dislocation under external stress,and may be continuously moved through bypass or cross--slip.
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    INFLUENCE OF AUSTENITIZING TEMPERATURE ON IMPURITIES SEGREGATION ALONG GRAIN BOUND ARIES IN 4330M STEEL
    SHI Qunxing;WU Jiansheng;LIN Dongliang Luoyang Ship Material Research Institute Shanghai Jiaotong University
    Acta Metall Sin, 1990, 26 (6): 78-80. 
    Abstract   PDF (258KB) ( 628 )
    The effect of austenitizing temperature on segregation of impurities alonggrain boundaries in 4330M steel has been examined by AES. The impurities segregation wascomputed quantitatively. Sulphur is revealed to segregate along austenite grain boundarieswhen steel quenched at 870 or 1000℃. No segregation will occur at quenching temperatureup to 1100 or 1200℃. However, the segregation becomes quite serious under stepped quenchingfrom 1200 to 870℃. The limitation of the Maclean expression for equilibrium segregation wasdiscussed.
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    MICROSTRUCTURE AND REVERSE SHAPE MEMORY EFFECT IN A Cu-Zn-Al ALLOY
    DONG Jianxin;CHEN Fumin;CHEN Jinming;LIU Wenxi Tianjin University
    Acta Metall Sin, 1990, 26 (6): 81-83. 
    Abstract   PDF (1081KB) ( 589 )
    The bainite structure related to the reverse shape memory effect has been observ-ed by means of TEM in a Cu-Zn-Al alloy. The reverse memory effect may be improved upto one order of magnitude under applied constraint stress. The widespread propagation of bai-nite was confirmed to be the diffusion controlled shear process by phenomina observed both theparabolic configuration of side interface of bainite plate and the twisting of intersected bainiteplates.
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    EXTRACTION KINETICS, MICELLIZATION AND INTERFACIAL CHARACTERISTICS OF A NEW MIXED EXTRACTANT SYSTEM
    YU Jingfen;JI Chen;PAN Xiaomei;XIONG Yigang Tsinghua University; Beijing
    Acta Metall Sin, 1990, 26 (6): 84-89. 
    Abstract   PDF (560KB) ( 518 )
    Study was made of the micellization, interfacial characteristics andextraction kinetics of a newly developed D_2 EHPA-H_2 RPA-Al~(3+) mixed system. In thesystem, more vigorous micellization and better interfacial acitivity of H_2RPA wererevealed. While it has a decreasing tendency to micellization and inter facial activitywith increase of D_2EHPA content. The adsorption behaviour of H_2RPA at the in-terface is quite contrary to that of D_2EHPA. The controlling mechanism of extra-ction kinetics for the non-micella mixed extractant system was confirmed as thetype of interfacial chemical reaction, and the equation for extraction rate was thusobtained. This non-micella extraction system of mixed extractants seems to befavourable to hydrometallurgy.
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    EXPLOSIVE HARDENING OF HIGH Mn STEEL
    LI Mingshan;ZHAO Shida;SHI Guoshun Institute of Mechanics; Academia Sinica; Beijing; Beijing Centre of Physical Testing and Chemical anolysis
    Acta Metall Sin, 1990, 26 (6): 90-93. 
    Abstract   PDF (1072KB) ( 513 )
    The explosive hardening of high Mn steel was simulated by using lightgas gun under selected ranges of impact load from 10 to 20 GPa and pulse durationfrom 0.04 to 1.6 μs. The experimental results show that a lot of twins formed inthe shocked high Mn steel may be the principal cause of the explosive hardening.
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    EFFECT OF POTENTIAL ON INTERACTION BETWEEN STRESS CORROSION CRACKING AND CORROSION FATIGUE OF AUSTENITIC STAINLESS STEEL IN BOILING 42% MgCl_2 SOLUTION
    FENG Tao;CHEN Liangshi;KE Wei Corrosion Science Laboratory; Academia Sinica; Shenyang
    Acta Metall Sin, 1990, 26 (6): 94-99. 
    Abstract   PDF (1429KB) ( 511 )
    The environment-sensitive fracture behaviour of 0Cr18Ni9Ti austeniticstainless steel in boiling 42% MgCl_2 under the specific load of low frequency andhigh mean stress was investigated from the relations and differences on crack gro-wth rates and fractographys between stress corrosion fatigue and stress corrosioncracking. The interaction between stress corrosi on cracking and corrosion fatiguewas also studied from fracture characteristics, with emphasison the effect of appliedpotential on the interaction.
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    EFFECT OF METAL-OXIDE DIFFUSION BARRIER ON INTERDIFFUSION OF ELEMENTS BETWEEN COATING AND SUBSTRATE
    SUN Biwu;GUAN Hengrong;SUN Xiaofeng;LI Tiefan Institute of Metal Research; Academia Sinica; Shenyang; Institute of Corrosion and Protection of Metals; Academia Sinica; Shenyang
    Acta Metall Sin, 1990, 26 (6): 100-104. 
    Abstract   PDF (755KB) ( 562 )
    The effect of LPPS Ni_3Al-Y_2O_3 diffusion barrier layer on interdiffu-sion of elements between coating and substrate has been investigated. It is foundthat retardation of interdiffusion is related to the amount of oxide in the diffusionbarrier layer. The retatdation is not remarkable when the content of Y_2O_3 is 8 wt-%,whereas the diffusion of Al, Co or Cr has all been notably retarded when thecontent of Y_2O_3 reaches 30 wt-%. The retardation effect of diffusion barrier is dif-ferent for different elements such as Al, Co or Cr.
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    STRUCTURAL FEATURE OF AS-CAST HIGH Cr INJECTION MICROALLOYING MARTENSITIC CAST IRON
    ZHANG Jinghui;LI Dajun;ZHAO Jiuzhou;JIA Jun;LI Jianhui Harbin Institute of Technology; Heilongjiang Association for Science and Technology; Harbin
    Acta Metall Sin, 1990, 26 (6): 105-109. 
    Abstract   PDF (1537KB) ( 618 )
    The microstructure of as-cast high Cr injection microalloying marte-nsitic cast iron and the substructure of martensite in it have been observed underSEM and TEM. The alloying element distribution related to phase formation, aswell as the various types of branch and distortion of carbide in the martensiticcast iron have been explored by using X-ray diffraction and electron probe analy-sis.
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    CHANGE OF ECCENTRICITY IN TUBE SINKING
    YAO Ruohao;ZHONG Jianhua;HUANG Jianfang;ZHANG Ruhua South Institute of Metallurgy; Ganzhou; Jiangxi
    Acta Metall Sin, 1990, 26 (6): 110-116. 
    Abstract   PDF (521KB) ( 570 )
    The rectification of eccentricity was revealed to be more effective intube sinking than drawing wan a mandral. The ratio of thickness to diameter oftube blank on both sides of thick and thin wall seems to be the principal influen-tial factor in rectifying eccentricity. The greater the initial outside diameter and theinitial wall thickness difference are and the less the initial wall thickness of thetube blank is, the better the rectification.
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    STRUCTURAL CHANGE IN HEAT AFFECTED ZONE AND ITS INFLUENCE ON PROPERTIES OF WELDED WHITE CAST IRON
    ZOU Zengda;WANG Yong;REN Dengyi Shandong Polytechnic University; Jinan
    Acta Metall Sin, 1990, 26 (6): 117-121. 
    Abstract   PDF (1623KB) ( 716 )
    The structure change in heat affected zone (HAZ) and its influence onproperties of welded white cast iron have been investigated by means of thermal cy-cle simulation technique. The structure of white cast iron at peak temperature 800℃is examined as cementite in pearlitic matrix, of which the hardness and impact to-ughness are the lowest in all temperatures during the tests. While the structure aftercyclic heating at high peak temperature is mainly cementite together with twin mar-tensite, of which the hardness and impact toughness are rather higher. The phaseboundaries, were fine precipitates occur, in the structure of low hardness are smoothand regular. Both cleavage and interphase fracture were revealed in the structure oflow hardness, but transgranular fracture was revealed in that of high hardness.
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    MICROSTRUCTURE AND PROPERTIES OF SiC_w/6061Al COMPOSITE
    MA Zongyi;YAO Zhongkai Harbin Institute of Technology
    Acta Metall Sin, 1990, 26 (6): 122-126. 
    Abstract   PDF (1697KB) ( 654 )
    The SiC_w/6061Al composite prepared by squeeze casting has a combi-nation of superior room temperature specific strength and modulus together with ex-cellent thermal properties. The extrusion can make an improvement on the strengthand ductility of the composite from 582 MPa as squeeze casted up to 639 MPa, andon the transformation from isotropic to the anisotropic structure. This seems to beexplained by the orientation of whiskers and the densification of dislocations inmatrix. TEM observation indicates that the stacking fault is the usual planar defecton the SiC_w surface.
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    FATIGUE BEHAVIOUR OF SiC_p/6061Al COMPOSITE
    YU Weicheng;YUAN Jincai;WANG Zhongguang Laboratory of Fatigue and Fracture for Materials; Institute of Metal Research; Academia Sinica; Shenyang
    Acta Metall Sin, 1990, 26 (6): 127-131. 
    Abstract   PDF (1587KB) ( 464 )
    The fatigue properties of the composite of 6061Al reinforced by 15v.-%SiC particles sized to 10--2.5μm have been examined in comparison with 6061Al.The microprocess of fatigue crack initiation and propagation as well as dislocationstructure have also been studied using SEM and TEM. For the composites reinforcedby SiC particles of two different sizes, the fatigue strength of both at 10~7 cycles is196 MPa, i.e. 25% greater than that of matrix alloy. If cycling life below 10~7, thefatigue strength of composite reinforced by coarse SiC particles is better than thatby fine particles. The voids and microcracks initiated at and near the interface be-tween SiC_p and matrix, where the higher density dislocations are presented, will pro-pagate and link up to form the fatigue crack. It is an important evidence to notethat the dislocation channels where screw dislocation can travel are formed near inter-face and corner region of SiC_p in the composite subjected to fatigue stress, demon-strating the relationship between fatigue crack initiation and dislocation movementin the SiC particles reinforced 6061Al composite.
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    CARBON FIBRE ELECTROPLATED BY Cu-Ni DUPLEX COATING AND ITS COMPOSITE
    SUN Shoujin;ZHANG Mingda Institute of Metal Research; Academia Sinica; Shenyang
    Acta Metall Sin, 1990, 26 (6): 132-136. 
    Abstract   PDF (1302KB) ( 656 )
    The carbon fibre electroplated continuously by a compound coating ofNi prior to Cu, the composite made of this carbon fibre together with Cu substratehave been investigated. The compatibility, between carbon fibre and duplex coatingand flexual strength, linear thermal expansion coefficient and electric resistivity ofthe composite have also been examined. Owing to the transformation of face-cen-tred-cubic Cu-Ni solid solution in the compound coating under high temperature,both the nodulizing shrinkage of Cu coating alone and the graphitization of carbonfibre accelerated by single Ni coating with a consequent loss of strength were imp-roved. Because of the dissolving of minute carbon fibre in the interfacial Cu-Ni so-lid solution, the bonding strength and flexual strength of the composite were signi-ficantly increased, and the length of carbon fibre pulled out on the fracture surfa-ce was obviously reduced. The interface of the composite seems to be of the disso-lution bonding.
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    MICROSTRUCTURE OF SILICON CARBIDE WHISKER
    XU Haigang;ZHU Jing;YUAN Hong;NING Xiaoguang;YE Hengqiang Central Iron and Steel Research Institute; Ministry of Metallurgical Industry; Beijing; Laboratory of Atomic Imaging of Solids; Institute of Metal Research; Academia Sinica; Shenyang
    Acta Metall Sin, 1990, 26 (6): 137-144. 
    Abstract   PDF (2537KB) ( 678 )
    The morphology, crystal defects and chemical compositions of surfacesin two kinds of SiC whiskers related to their growth mechanism have been studiedby means of electron microscopy and surface chemical analysis. Based upon the expe-rimental results, five criteria for evaluating the whisker microstructure were sugge-sted as: proportion of the perfect single crystals, morphology and dimensions, defectsand their distribution, the bulk and surface chemistries, and crystallographic charac-ters.
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    SAM AND XPS STUDIES ON SURFACE SEGREGATION OA SUBSTRATE ELEMENTS IN Au-Ni-KOVAR ALLOY SYSTEM
    QI Yunxin;TANG Wentai;XIA Jianguo;LI Wang;ZHAN Zhenzong Nei Monggol Institute of Metallic Materials; Baotou; Institute of Physical and Chemical Engineering Research; Tianjin
    Acta Metall Sin, 1990, 26 (6): 145-150. 
    Abstract   PDF (1028KB) ( 644 )
    The surface segregation of substrate elements through the Au layer onAu-Ni-Kovar alloy system specimens heated at 250--350℃ for 0.5 to 1.5 h in airhas been studied by SAM and XPS. the segregation mechanism was revealed that theNi and Co diffuse through Au layer along grain boundaries and then spread overthe Au-plated surface. The adsorption of oxygen and oxidation seem to be the drivingforce of surface segregation of Ni and Co. The phenomenon of absorption of watervapour on specimen surface was also found to be caused by the segregation.
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    A SOLUTION OF MINIMUM NORM FOR QUANTITATIVE PHASE ANALYSIS BY STANDARDLESS X-RAY DIFFRACTION
    ZHAO Han;GONG Yansheng;SHEN Jingyuan;RUAN Qikuan;JIN Jialing;ZHU Hanyu Research Institute of Qiqihar Steel Works
    Acta Metall Sin, 1990, 26 (6): 151-155. 
    Abstract   PDF (374KB) ( 569 )
    A new expression of quantitathe phase analysis by standardless X-raydiffraction has been derived using intensity matrix of vector modulus. The criterionof standardless X-ray diffraction analysis was suggested, so as to separate the diffra-ction pettern of every phase from that of sample. The optimal solution could beobtained by the least squares regression.
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    DISSOLUTION EQUILIBRIUM OF Mg VAPOUR IN LIQUID Fe
    ZHANG Xiaodong;HAN Qiyong;CHEN Dong University of Science and Technology Beijing; Hebei Institute of Metallurgy
    Acta Metall Sin, 1990, 26 (6): 156-158. 
    Abstract   PDF (247KB) ( 463 )
    A study of the dissolution equilibrium of Mg vapour in liquid Fe was carriedout at 1873 K in a two-temperature-zone furnace by use of the vapour pressure method. Theequilibrium constant for the reaction Mg(g)=[Mg] and free energy of solution obtained are:K=a_(Mg) /p_(Mg) =0.0236△G°(wt--%)=58300 J/mol
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    EFFECT OF EXPLOSIVE CONSOLIDATION PARAMETERS ON CONSOLIDATION QUALITY
    GAO Juxian;ZHANG Ke;ZHENG Zhemin Institute of Mechanics; Academia Sinica; Beijing
    Acta Metall Sin, 1990, 26 (6): 159-161. 
    Abstract   PDF (261KB) ( 426 )
    Two-dimension consolidation under the cylindrical converging shock wave hasbeen studied. The major parameters influenced on the explosive consolidation quality are thespecific energy, detonation pressure and specific impulse. It seems to be favourable to impro-ving consolidation quality by a lower but slightly higher than critical detonation pressure and ahigh specific impulse.
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