DENG Rongying ZHOU Aihua JIANG Huaiqing LI Chunxiu Institute of Mechanics
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Academia Sinica
,
Beijing
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ChinaZHANG Liqing
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SUN Yutian Beijing Institute of Engineering
,
Beijing
,
China [Originally published in ACTA METALL SIN(CHINESE EDN)25(3)1989 pp A219—A225
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Associate Profes sor
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Institute of Mechanics
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Academia Sinica
,
Beijing
,
China
金属学报(英文版)
The effect of pearlite interlamellar spacing(d)from 0.31 to 0.77 μm of T8 steel on fatigue crack propagation near threshold has been investigated at different stress ratios(R).The closure stress intensity factor(K_(cl)),the threshold value(ΔK_(th))and crack tip opening dis- placement range(ΔCOD)were measured.The results show that pearlite interlamellar spac- ing in this range has no effect on K_(cl),but has effect on the threshold value in low stress ratio. The threshold value is higher for materials with larger interlamellar spacing.No matter what the stress ratio is,during the propagation near threshold,the propagation rate will be the same,provieded the crack tip opening displacement range is the same. Metallurgical examinations were also carried out to show that the crack propagation path is sensitive to mierostructure.The crack always propagates along either boundary of pearlite colony or ferrite lamellar in pearlite.
关键词:
pearlitic steel
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null
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QIAO Lijie LIU Rui XIAO Jimei University of Science and Technology Beijing
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Beijing
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China
金属学报(英文版)
The effects of stress components on nucleation sites and propagation directions of stress cor- rosion cracks in brass were investigated with specimens under mode Ⅱ and mode Ⅲ loadings. The results indicated that under mode Ⅱ loading,stress corrosion cracks nucleated on the site with maximum normal stress component and propagated along the plane perpendieular to the maximum normal stress,under mode Ⅲ loading,the stress corrosion crack was not evident on the 45°plane due to the general corrosion in aqueous solution with high NH_4OH concentra- tion,while stress corroded in aqueous solution with low NH_4OH concentration, numerous cracks with spacings of 10—150μm were found on the 45°plane with maximum normal stress and no stress corrosion cracks was observed on the plane with maximum shear stress.
关键词:
stress corrosion cracking
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null
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WANG Huaming Institute of Metal Research
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Academia Sinica
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Shenyang
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ChinaZHANG Qing Central Iron and Steel Research Institute
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Ministry of Metallurgical Industry
,
Beijing
,
ChinaSHAO Hesheng Beijing Graduate School
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China University of Mining and Technology
,
Beijing
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China Institute of Metal Research
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Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The role of austenite in impact-abrasion process was studied on the basis of the impact-abrasion test results of a newly developed austenite-bainitic ferrite dual-phase abrasion-resistant steel with high strength,high toughness and high strain-hardening ability. It is found that the morphology,distribution and mechanical stability,rather than the volume fraction,of austenite govern the impact abrasion behaviour.Only the appropriate amount of fine and evenly dispersed austenite with adequate mechanical stability in high strength matrices,contribute effectively to the irnpact-abrasion resistance of the materials.While large quantity of coarse austenite with poor mechanical stability,especially when it acted as a continuous matrix of the material,is extremely detrimental to impact-abrasion resistance.
关键词:
austenite
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null
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null
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XU Xiangxing SU Yi ZHOU Wei Tsinghua University
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Beijing
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ChinaCAI Qigong Central Iron and Steel Research Institute
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Ministry of Metallurgical Industry
,
Beijing
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China XU Xiangxing
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Dept.of Mechanical Engineering
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Tsinghua University
,
Beijing
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100084
,
China
金属学报(英文版)
The cleavage fracture mechanism of granular bainitie weld metal in 15MnVN steel has been investigated.SEM observation of a special specimen for revealing simultaneously fracture sur- face and microstructure shows that the cleavage of the weld is initiated by M-A constituent. The 95th percentile equivalent diameter of M-A constituent controls the cleavage fracture stress of the weld metal.
关键词:
granular bainite
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HU Fengxia State Key Laboratory of Magnetism
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Institute of Physics
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Academia Sinica
,
Beijing
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ChinaCHEN Jinchang Beijing Teacher's College
,
Beijing
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ChinaSHEN Baogen GUO Huiqun State Key Laboratory of Magnetism
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Institute of Physics
,
Academia Sinica
,
Beijing
,
China
金属学报(英文版)
Curie temperature of amorphous alloys Co_(90-x)Cr_x Zr_(10) decreases linearly with increas- ing x.Average magnetic moment per magnetic atom Co or Cr is 1.51 μB or -3.62 μB respectively.The temperature dependence of spontaneous magnetization at low temper- atures is in agreement with Bloch's T~(3/2) law.The spin wave stiffness constant decreases with increasing x from 4 to 20.The range of interaction is 2—3 atoms for x=4 and nearest neighbour atom for x=20.The crystallization temperature increases mono- tonically with increasing x.It may relate to the average number of outer electrons per atom.The crystalline phase components of heat-treated alloys were analyzed by X-ray diffration and thermomagnetic measurement.
关键词:
amorphous state
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null
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null
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YANG Jilian ZHANC Baisheng DINC Yongfan China Institute of Atomic Engergy
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Beijing
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ChinaYANG Yingchang ZHANG Xiaodong Peking University
,
Beijing
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ChinaPAN Shuming General Research Institute for Non-Ferrous Metals
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Beijing
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China associate professor
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P.O.Box 275
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Branch No.30
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Beijing 102413
,
China
金属学报(英文版)
The N occupying sites and magnetic structures in R_2Fe_(17)N_x(R=Y,Dy,Nd)are de- termined by neutron diffraction.The effects of the site occupation of N on magnetic properties are discussed primarily.
关键词:
neutron diffraction
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RAO Jianxi Naval Academy of Engineering
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Wuhan
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China MA Ruzhang University of Science and Technology Beijing
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Beijing
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China HE Yusheng Tsinghua University
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Beijing
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China MA Ruzhang Professor
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Department of Metal Physics
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University of Science and Technology Beijing 100083
,
Beijing
,
China
金属学报(英文版)
Measurements by using the ultrasonic technique together for electric resistance verified that the first sound velocity valley on cooling is mainly due to the soft-mode of driving the com- mensurate phase transition,and the second one due to the soft-mode of driving the martensitic transformation.The starting point,R_s,and finishing point,R_f,of the commensurate phase transition of the alloy have been determined.
关键词:
incommensurate phase transition
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null
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SUN Enxi Dalian Railway College
,
Dalian
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ChinaYANG Dazhi Dalian University of Technology
,
Dalian
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ChinaXU Zuyao (T.Y.Hsu) Shanghai Jiaotong University
,
Shanghai
,
ChinaYANG Fuming ZHAO Ruwen Institute of Physics
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Academia Sinica
,
Beijing
,
China YANG Dazhi
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Professor
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Dalian University of Technology
,
Dalian 116024
,
China
金属学报(英文版)
The pulsed magnetic field induced martensitic transformation with isothermal and athermal kinetics in Fe-2Ni-4Mn(wt-%)alloy has been studied by means of magnetization measurements,optical microscopy and thermodymical analyses.It is shown that there exits a critical magnetic intensity for induing martensitic transformation at a given temperature above Ms.The critical magnetic field increases linearly with increasing ΔT= T-M_S.The magnetic field strongly promotes the athermal martensitic transforamtion and restrains the isothermal one.The entropy change ΔS for athermal transformation at Ms is 4.13 J/mol· K.The effect of magnetic field on martensitic transformation in Fe-21Ni-4Mn alloy is main- ly due to Zeeman effect.Lath,plate and butterfly martensities were observed under magnetic field.
关键词:
magnetic field-induced martensitic transformation
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null
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LIU Ping Institute of Aeronautical Material
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Beijing
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ChinaXU Changgan Beijing University of Aeronautics and Astronautics
,
Beijing
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China XU Changgan
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Associate Professor
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Group 102
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Beijing University of Aeronautics and Astronautics
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37 Xueyuan Road
,
Beijing 100083
,
China
金属学报(英文版)
The electrochemical behaviour,which is presented by means of anodic polarization curves.of the component phases in Ti and Ti alloys in aqueous solutions of fluorhydrie acid,chhnhydric acid and amber acid has been investigated.The results indicate that the electrochemical behaviour of the allloys depends upon the composition and the lattice type.The corrosion of x and x′phase in actire region and that of β phase in passive region are the dominant corrosion behaviour.
关键词:
Ti alloy
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null
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ZHANG Dengxia MA Chenghui CAI Ming Institute of Mechanics
,
Academia Sinica
,
Beijing
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ChinaAI Baoren ZHANC Jinyuan ZHU Ruizhen LIU Chunlan Central Iron and Steel Research Institute
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Ministry of Metallurgical Industry
,
Beijing
,
China Associate Professor
,
Institute of Mechanics
,
Academia Sinica
,
Beijing 100080
,
China
金属学报(英文版)
Observations of microstructure of explosive compacts made of Al or Al-Li alloy powders by atomization with water,nitrogen or ultrasoic Ar gas were carried out under optical and scanning electron microscopes.The rsults indicate that super quality explosive compact can only be obtained by powders of which the thickness of the oxide layer is less than 30 nm.
关键词:
Al powder
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null
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null
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