Z.F.Peng1)
,
Y.Y.Ren1)
,
Q.S. Mei1)
,
Y.Q.Wang2)
,
X.Y.Zhang2) and M.S.Ye2) 1) Department of Materials Engineering
,
Wuhan University of Hydraulic and Electric Engineering
,
Wuhan430072
,
China 2) Department of Superalloys
,
CentralIron and Steel Research Institute
,
Beijing430072
,
100081 China
金属学报(英文版)
Theeffectsof Nband Ti+ Nb microalloyingon mechanicalpropertiesand rupturelifeunder900 ℃ tensiletest on alloy GH652 were studied. Among theoriginalalloy GH652 and its Nb/ Ti+ Nb microalloyed alloys, the Ti+ Nb microalloyed alloy exhibited optimum com bined900℃ tensilestrength and plasticity and longer 900℃ 49 MPa prolonged tensile rup turelife as well. The role of refractory alloying elementscould be effectively brought intoplay with highertemperaturesolution treatment. Coordination strengthening of Matrix andgrain boundary wasthekeyfactoroflifetimeextension andthe mobilityof dislocationsinthematrix wasresponsableforthe plasticity ofthe micro alloyedsamples.
关键词:
GH652 Nb/ Ti+ Nb micro alloying
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null
,
null
,
null
QIAO Lijie LIU Rui XIAO Jimei University of Science and Technology Beijing
,
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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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
