CHU Youyi ZHANG Sanhong HE Xinlai KE Jun(T.Ko) University of Science and Technology Beijing
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China CHU Youyi Professor
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The Nonferrous Metals Society of China
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Room 602
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B12
,
Fuxing Road
,
Beijing 100814
,
China
金属学报(英文版)
In consideration of the local equilibrium among vacancies,solute atoms and vacancy-solute atom complexes and the influence of equilibrium grain boundary segregation,theoretical dy- namic formulas for non-equilibrium grain boundary segregation of solute have been derived on the basis of the vacancy-dragging mechanism.Theoretical calculation by computer has been carried out for the non-equilibrium segregation of boron to austenitic grain boundaries during isothermal holding and continuous cooling after heating at high temperatures.The re- suits agree well with those obtained from experiments.
关键词:
solute
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null
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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
,
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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Materials and Corrosion-Werkstoffe Und Korrosion
Carbon steels were pre-corroded in atmospheres containing certain pollutants such as sulfur dioxide or hydrogen sulfide or nitrogen dioxide for certain period of time. Then the pre-corroded samples were further exposed at two central test stations in the country to evaluate the influence of pre-corrosion on the behavior of long-term atmospheric corrosion of carbon steel by gravimetric measurement and rust examinations with FT-IR and XRD. The results showed that the corrosion rates of every kind of carbon steel at Jiangjin station were two times higher than that at Beijing station. The influence of different pre-corrosion conditions on the long-term atmospheric corrosion of carbon steel was analyzed. It followed that the pre-corrosion conditions made the long-term atmospheric corrosion performance of three kinds of carbon steels different, but the differences were small. Among the three pollutants, NO2 showed the strongest influence to the process. As the exposure time was going on, all the samples corroded slowly at Beijing and Jiangjin stations.
关键词:
pollution parameters;prediction;outdoor;rust
