LU Feng CAO Fengyu LI Chengji University of Science and Technology Beijing
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Beijing
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ChinaZHANG Yongxiang CHEN Yonggang Beijing Institute of Machine Tools
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Beijing
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China Faculty of Metallograph
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University of Science and technology Beijing
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Beijing 100083
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China
金属学报(英文版)
Effect of Ca on hardenability and CCT diagram of steel 58CrV has been investigated by means of end-quenching and thermal expansion.An addition of 0.006 wt-%Ca to the steel may improve the hardenability,reduce the critical cooling rate of transformation of pearlite or bainite under continuous cooling and increase the M_s.AES analysis showed that Ca segre- gates markedly along austenitie grain boundaries,and accelecrates the segregation of C,Cr and Si.It is believed that besides towards deoxidizing and desulphurizing as well as improving sulphide morphology,a trace of Ca in steel 58CrV behaves towards microalloying.
关键词:
Ca
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HU Benfu LI Huiying WU Chengjian ZHANG Shouhua University of Science and Technology Beijing
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Beijing
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China Associate Professor
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Dept.of Material Science and Engineering
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University of Science and technology Beijing
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Beijing 100083
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China.
金属学报(英文版)
The solidification microstructure and phase composition of Ni-base superalloy FGH95 pow- der with different mesh size have been investigated.The structure transition was found from dendrite in major into cellular structure as the powder size reduces and the cooling rate in- creases.The predominant phase was identified as MC-type carbide,with different morphologies,which may be related to their composition and the condition of solidification.Minor phases,such as boride,Laves and primary γ' are also present as ac- companiments of the carbide.
关键词:
powder metallurgy
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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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