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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LIU Yuesheng ZHAO Xianguo LIU Zhizhong XIE Xishan Beijing Institute of Aeronautical Materials
,
100095
,
China. University of Science and Technology Beijing
,
100083
,
China.To whom correspondence should be addressed.
材料科学技术（英文）
On the basis of an investigation on σ phase in Ni-base cast superalloy K24 and the results about σ phase in other Ni-base superalloys,an embrittl- ing mechanism and a softening mechanism,by which platelike σ phase weakens the Ni-base superalloys,have been proposed.It is considered that the platelike morphology and the habit precipi- tation along{111}of σ phase are necessary condi- tions for both mechanisms.The embrittling mecha- nism is dominant at room temperature and high strain rate,and the softening mechanism is domi- nant at high temperature and low strain rate.Ac- cording to the idea of the softening mechanism and the analyses of σ phase and alloy compositions,it is considered that Nb,Mo and W in the alloys may be resistant to the detrimental effect of σ phase on the stress-rupture properties of the alloys.
关键词:
Ni-base superalloys
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LIANG Yong LI Ruiguo Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
ChinaInstitute of Corrosion and Protection of Metals
,
Aademia Sinica
,
Shenyang
,
110015
,
China
材料科学技术（英文）
Recent advances in laser coating technology including laser cladding,laser surface alloying and laser vapour deposition in China are reviewed in this paper.
关键词:
laser
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