CHEN Qizhi WU Xingfang KE Jun (T Ko) University of Science and Technology Beijing
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Beijing
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China
金属学报(英文版)
The butterfly martensite nuclei in an Fe-Ni-V-C alloy were observed under TEM,they con- sist of enveloping dislocations with Burger's vector(1/2)[]_(fcc) and arrays of dislocations with Burger's vector(1/2)[10]_(fcc) piled up within the former.The enveloping dislocations and the arrays of dislocations provide the required shear when the planes(11)_(fcc)move with each other to alter their stacking order and change into the planes(110)_(bcc) respectively.The necessary adjustment of the spacings is provided by the dislocations in martensite.The crystallographic relationship after double-shear is K-S one.
关键词:
butterfly martensite
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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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