LIU Ning CUI Kun Huazhong University of Science and Technology
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Wuhan.China DENG Zonggang Hefei University of Technology
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Hefei
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China CHENG Benpei KONG Jie Institute of Solid State Physics
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Academia Sinica
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Hefei
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China Doctorate student
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Department of Mechanical Engineering No.2
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Huazhong University of Science and Technology
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Wuhan 430074
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China
金属学报(英文版)
Microstructure of the deepest zone of high speed steel W6Mo5Cr4V2(M2)melt after laser fu-sion was found to be so fine as the ehill zone of a solidified ingot.When narrower chill zoneformed,the long columnar dendrites grow into the melt and then the fine equiaxed cellularstructure appears in upper melt region nearly surface.The substructure of cellular grains anddendrites was observed to consist of martensite and retained austenile,while the carbides asM_6C_■ Cr_7C_3 and MC distributed at their boundaries.It is believed that the highermicrohardness up to HV_(0.1)=865-960 of the laser fused structure of the alloy is due to the oc-currence of martensite.
关键词:
High speed steel W6Mo5Cr4V2(M2)
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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
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Academia Sinica
,
Hefei
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China Associate Professor
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Institute of Metal Research
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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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YI Huchun GE Tingsui (T.S.Ke) Institute of Solid State Physics
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Academia Sinica
,
Hefei
,
China GE Tingsui
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Professor
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Laboratory of Internal Friction and Defects in Solids
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Institute of Solid State Physics
,
Academia Sinica
,
Hefei
,
China
金属学报(英文版)
Internal friction and elastic modulus of ternary Mn-Cu-Al alloys containing 56—60 wt-% Mn,0-3.59 wt-% Al were measured with acoustic frequency,1 kHz,in the tempera- ture range of-150 to 150℃.It was found that when the specimen was aged in the temperature range under the spinodal curve within the miscibility gap(400—500℃),the internal fric- tion increases with an increase of the aging time and reaches a maximum value at a certain ag- ing time which is shorter with a higher aging temperature.Two internal friction peaks which did not appear before the aging were observed above room temperature after a definite aging time.These are respectively the martensitic tranformation peak and the relaxation peak orig- inating from the stress-induced movement of the twin boundaries.The former peak shifts to- ward higher temperatures with an increase of the aging time,whereas the relaxation peak ap- pearing at 15℃,is independent of the aging time and temperature.The activation energy as- sociated with the relaxation peak was found to be 0.56 eV which is about the same as that of the relaxation peak in binary alloy containing 90 wt-% Mn.It was also found that the hardness,strength and the brittleness of the specimen increase when aged below the spinodal curve within the miscibility gap.The addition or Al enhances the strength but reduces the in- ternal friction of the specimen.A choice of suitable aging time and temperature can give an optimum compromise of high strength and high internal friction.Analysis of experimental re- sults suggests that spinodal decomposition leads to Mn-rich zones in the specimen and thus causes the phase transformation and the change of mechanical properties of the specimen.
关键词:
internal friction
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DU Jiaju TONG Shihua Institute of Solid State Physics
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Academia Sinica
,
Hefei
,
China [Originally published in ACTA METALL SIN(CHINESE EDN)25(3)1989 pp A226—A228
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Associate Professor
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Institute of Solid State Physics
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Academia Sinica
,
Hefei
,
China
金属学报(英文版)
Optical microscope,SEM and IMMA investigation show that a strong interaction between hydrogen and calcium aluminate inclusions containing MgO may occur in medium carbon steels.This causes the hydrogen accumulating around the inclusions and reducing the ductility of the steel.
关键词:
hydrogen
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ZHU Xianfang ZHANG Lide Institute of Solid State Physics
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Academia Sinica
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Hefei
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China Research Assistant
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Institute of Solid State Physics
,
Academia Sinica
,
Hefei
,
China
金属学报(英文版)
The characteristics of the low frequency internal friction and the modulus effect associated with the non-equilibrium spinodal pretransformation and the following discontinuous trans- formation was investigated in an as-quenched eutectiod Al-Zn alloy.It was observed that the loss of the stability in the lattice,which corresponded to the large-amplitude long-wavelength static concentration wave in the non-equilibrium spinodal pretransformation,did not induce any effect of localized soft modulus.Although there are two aging internal friction peaks in phase transformation which correspond to the appearance and disappearance of the coherency in spinodal pretransformation and the maximum of the interface area in the discontinuous transformation respectively,the effect of localized soft modulus did not take place yet.
关键词:
spinodal pretransformation
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CHENG bolin GE Tingsui (T.S.Ke) Laboratory of Internal Friction and Defects in Solids
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Institute of Solid State Physics
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Academia Sinica
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Hefei
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China Professor Laboratory of Internal Friction and Defects in Solids
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Institute of Solid State Physics
,
Academia Sinica
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Hefei
,
230031
金属学报(英文版)
Internal friction and micro-creep measurements were performed with high-purity aluminium bamboo-crystal specimens.The relaxation strength was found to decrease with the decrease of temperature and became zero at about 0.4 T_m(T_m is the melting temperature).This re- flects the occurrence of local disordering in the bamboo boundary region at this temperature. This result conforms to the picture of grain-boundary disordering constructed by atomic simulation studies.
关键词:
Grain boundary disordering
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YU Xuejie WANG Jianlin Shanghai Iron and Steel Research Institute
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Shanghai
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ChinaZHOU Tianjian Anhui Institute of Technology
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Hefei
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China YU Xuejie
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Senior Engineer
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Shanghai Iron Steel Research Institute
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1001 Taihe Road
,
Wusong
,
Shanghai
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China.
金属学报(英文版)
In order to clarify that the IFP and the “Type 2”α phase are also arising from TiC,a metastable β-Ti alloy was selected for investigation in this work.The results showed that af- ter heating the alloy just below the α+β→β transus temperature and quenching,the TiC lay- er existed at the α/β interface.The morphology of TiC is similar to that of the IFP arising from TiH_2 in the α-β two-phase alloys.The IFP TiC also provided an easy crack path or the crack initiation sites.The fracture is also identical to that caused by IFP TiH_2.The arced diffractions(characteristic of “Type 2”α)were found in the selected area diffraction pat- terns of some specimens which had been isothermally aged after solid solution treatment.The particles which bring on the arced diffractions may be TiC on the basis of structure and lat- tice parameter analysis,not the so called “Type 2”α phase.
关键词:
interface phase(IFP)
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LIU Senying GAO Zhe LI Keng University of Science and Technology Beijing
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ChinaLI Junqing China University of Science and Technology
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Hefei
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ChinaWANG Congyu Central Iron and Steel Research Institute
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Ministry of Metallurgical Industry
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Beijing
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China Doctoral student
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Postgraduate School
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Cemral Iron and Steel Research Institute.Ministry of Metallurgical Industry
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Beijing
,
China
金属学报(英文版)
Based on the feature of crystal sites occupied by alloying elements,a model cluster,investi- gating the interaction mechanisms of nonmagnetic element Cu in RECo_5 type alloy,has been presented.The electronic structure has been calculated with SCF-X_a-SW method.The calcu- lating results show that,after Cu replaced 2c crystal site Co,the energy spectrum of the mod- el cluster will move towards a shallow trap po.tential,the energy gap becomes small,the charge among the atoms will redistribute,and some new states to which impurity contributes will pro- duce.Partial-wave local density of states gives the interaction between atoms.Results of Hellmman-Feynman force show that the thermal expansion anisotropy of the model cluster decreases considerably after Cu substitutes for 2c crystal site Co.
关键词:
intermetallic compound
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WANG Weihua XIAO Keqin CHU Zhaoqin DONG Yuanda Institute of Solid State Physics
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Academia Sinica
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Hefei
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ChinaWANG Genmiao Centre of Structural Analysis
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China University of Science and Technology
,
Hefei
,
China
金属学报(英文版)
Amorphous Al_(80)Fe_(20) powder which can hardly be obtained using conventional rapid quenching technique was directly prepared from crystalline Fe and A1 powders by means of mechanical alloying process.The amorphization process was examined by X-ray analysis and Mssbauer spectroscopy,and the thermal behaviour was studied by DSC.The results show that the rate of amorphization is controlled by the diffusion reaction at the interfaces and changes with the milling time.The effect of milling conditions on amorphization by mechanical alloying was al- so investigated.
关键词:
mechanical alloying
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ZHU Kai University of Science and Technology of China
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Hefei
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China WANG Chongyu Central Iron and Steel Research Institute
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Ministry of Metallurgical Industry
,
Beijing
,
China Central Iron and Steel Research Institute
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No.13
,
Taipingzhuang
,
Beijing
,
China
金属学报(英文版)
The calculation of electronic structure of γ'-Ni_3Al phase with or without Mg and W by the Recursion and LCAO methods clarified that Mg and W atoms lose their outer electrons par- tially after they entered γ'-Ni_3Al.It causes the reduction of the radii of the atoms.So it is preferable for Mg atom to enter γ'-phase by the substitution.The interaction between Mg and γ'-phase matrix may be strengthened and a more stable structure of γ'-phase may be formed while Mg and W entered γ'-Ni_3Al simultaneously.
关键词:
superalloy
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