GAO Yan LI Dejun CAO Zhiben Dalian University of Science and Technology
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Dalian
,
Liaoning
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China LI Dejun
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Lecturer
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Department of Materials Engineering
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Dalian University of Science and Technology
,
Dalian
,
Liaoning
,
China
金属学报(英文版)
The microstructure of Cr_(25)Ni_(20)stainless steel under plastic deformation up to 50% has re- vealed an even distributed twins,micro-twins and deformation bands.The σ-phase formation in 800℃ aged specimens is accelerated by its nucleation at either deformation twins or recrystallized grain boundaries under less or more deformation respectively.In the recrystallized zone,the recrystallization is prior to the precipitation of σ-phase.Although recrystallization may accelerate the formation of σ-phase,it is not essential.The twins and micro-twins produced by deformation may also provide the additional nucleation sites.
关键词:
plastic deformation
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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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