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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WANG Fuhui LOU Hanyi WU Weitao Corrosion Science Laboratory
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Institute of Corrosion and Protection of Metals
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Academia Sinica
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Shenyang
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China Research Assistant
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Institute of Corrosion and Protection of Metals
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Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
An investigation was carried out of the resistance to cyclic oxidation of the as-cast normal-grained Co-30Cr-5Al alloy substrate at 1000℃ in air together with its sputtered coating of microcrystallized CoCrAl alloy grains sized less than 0.5μm.Acoustie emissi on counts showed that the initially formed Al_2O_3 scale on the bare alloy substrate cracked and spalled severely off after only one or two cycles on cooling and then the worse protective layer of Cr_2O_3 and CoCr_2O_4 spinel occurred on surface.While such substrate coated with sputtered microcrystallized CoCrAl alloy film was not damaged under oxidation even through 100 cycles at 1000℃.In comparison with the normal-grained alloy,the microcrystallized al- loy,coating of similar constitution exhibite excellent resistance to oxide spalling on surface.
关键词:
microcrystallized CoCrAl coating
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LU Yuehua Kunming Institute of Precious Metals
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Kunming
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ChinaLIU Chunpeng Kunming Institute of Technology
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Kunming
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China Research Assistant
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Laboratory No.1
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Kunming Institute of Precious Metals
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Kunming 650031
,
China
金属学报(英文版)
Reaction between Cu_2S and Cu_2O was investigated at 1150 to 1250℃.The reaction rate in- creases with the increase of surface area of Cu_2O grains and depends unobviously on temper- ature.At the suggestion of controlling step of reaction rate being oxygen diffusion through the liquid layer along reaction boundaries,two final kinetical equations would be made as follows: x=6.69×10~(-2)At for 0<α<0.74 and ln(l-α)=-A(9.83×10~(-2)t+1.76)for 0.74<α<1,where α is SO_2 evolved in time t and A is surface area of Cu_2O particles.
关键词:
Cu_2O
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KANG Zengqiao GAI Xiuying LI Jiabao WANG Zhongguang State Key Laboratory for Fatigue and Fracture of Materials Institute of Metal Research
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Academia Sinica
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Shenyang
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China Research Assistant
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Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
Influence of residual stress and surface morphology induced by shot-peening on fatigue behav- ior of a medium temperature tempered spring steel 60 Mn has been studied.The compressive residual stress induced in the near-surface region may improve fatigue limit from 930 to 1010 MPa,and the very high tensile residual stress in the interior may reduce it from 1010 to 940 MPa,whereas the severe surface damage may cause a drop-off of it from 1010 down to 800 MPa.Fatigue cracks initiated in such position where the equivalent Mises stress,including residual stress,exceeded the local strength of the material.The compressive residual stress, induced by shot-peening,may intensify the effect of crack closure,so as to decrease the crack growth rate.
关键词:
shot-peening
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