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
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Hefei
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China Associate Professor
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Institute of Metal Research
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Academia Sinica
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Shenyang 110015
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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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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
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Academia Sinica
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Hefei
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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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YI Huchun GE Tingsui (T.S.Ke) Institute of Solid State Physics
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Academia Sinica
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Hefei
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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
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Academia Sinica
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Hefei
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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
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Hefei
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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
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Hefei
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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
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Academia Sinica
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Hefei
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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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