W. H. JIANG
,
X.D. YAO
,
H.R. GUAN
,
and Z. Q. HU(Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China)(Shenyang Polytechnic University
,
Shenyang 110023
,
China)
金属学报(英文版)
The high temperature high cycle fatigue behaviour of a directionally solidified Co-base superalloy was investigated. The alloy has saperior fatigue resistance at 900℃ and its fatigue strength is up to 295MPa. Its σ-Nf curve is characterized by three distinct zones. The stronger dependence of Nf on or in the high .and low stress zones results from multiple fatigue crock initiation sites produced by high stress and oxidation effect in a prolonged exposure, respectively.
关键词:
directional solidification
,
null
,
null
,
null
Chinese Science Bulletin
A study was carried out in order to investigate the effect of contaminants and meteorological variables on the rust layer of carbon steel exposed in Shenyang urban atmosphere. Seven kinds of contaminants and twelve kinds of meteorological parameters were also registered in order to correlate the data with respect to corrosion rate and the stepwise multiple regression analysis was carried out in order to obtain the best regression model. The sum of rainfall time as well as sunshine time and the concentration of H(2)S could stimulate initial atmospheric corrosion of carbon steel. The initial atmospheric corrosion kinetics of carbon steel was observed to follow the cubic equation. The corrosion products were analyzed by XRD and the transformation of phases in different periods was discussed.
关键词:
contaminants;meteorological parameters;carbon steel;urban atmospheric;corrosion;stepwise multiple regression;corrosion products;rust;pollution
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
,
null
,
null
,
null
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
,
null
,
null
,
null
,
null
Yang LUO
材料科学技术(英文)
Due to continued growth in key markets, a broadening of application base and performance improvements, the market demands of NdFeB magnet increased steadily in 1998, and the global output of sintered NdFeB magnet exceeded 10,000 t, in spite of the economic recession in Asia. In 1998 China produced 3,850 t sintered NdFeB block magnet, with an annual growth rate of +22% over the output in 1997.
关键词: