HAN Haiou LIN Qin WEI Shoukun University of Science and Technology Beijing
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100083
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China.
材料科学技术（英文）
The phase diagram of the binary system MnO-Nb_2O_5 was studied by means of the differential thermal analysis(DTA),X-ray diffraction analysis and scanning electron microscopy(SEM).Thermodynamic da- ta of the new compounds 4MnO·Nb_2O_5 and MnO·Nb_2O_5were found as follows: 4MnO·Nb_2O_5:t_m=1398±2℃ △H_m=129000(J/mol) △S_m=77(J/mol,K) △G_m~o=129000-77T(J/mol) MnO·Nb_2O_5:t_m=1499±2℃ △H_m=86940(J/mol) △S_m=49.6(J/mol,K) △G_m~o=86940-49.6T(J/mol) The eutectic parameters for the system are given below: t_(E1)=1383±3℃ N_(E1(MnO))=0.896 t_(E2)=1312±2℃ N_(E2(MoO))=0.713 t_(E3)=1400±4℃ N_(E3(MnO))=0.231
关键词:
phase 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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