XIE Changsheng SUN Peizhen ZHAO Jiansheng CHEN Yuqiu Huazhong University of Science and Technology
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Wuhan
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China XIE Changsheng Associate Professor
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Department of Mechanical Engineering No.2
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Huazhong University of Science and Technology
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Wuhan 430074
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China
金属学报(英文版)
The microstructures of Fe-Mn-Ni-Cr steels with medium carbon and the effect of alloy ele- ments on them have been investigated by means of X-ray diffraction quantitative phase ana- lyses,metallography and hardness tests.The volume fraction of martensite in steels quenched at 1100℃ can be expressed as: f_M~(1100)=162.643-15.482Mn-7.36Ni-4.286(Cr+Mo+V) Based on this expression,the quasi-equilibrium microstructure diagram has been obtained.It is shown that the effect of Mn on the austenite stability is greater than that of Ni.The equiva- lent [Ni]=2.104Mn+Ni and equivalent [Cr]=Cr+Mo+V. The driving force for martensite transformation at M_s point has been calculated to he drastically decreased by element Mn.
关键词:
quasi-equilibrium microstructure diagram
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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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