S.G. Tian
,
L.T. Zhang
,
H. M. Shao
,
L.J. Zou
,
T.F. Li
,
and H. C. Yang (Department of Materials Science
,
Shenyang Polytechnic University
,
Shenyang 110023
,
China) (Corrosion Science Laboratory
,
Institute of Corrosion and Protection of Metals
,
Chinese Academy ofSciences
,
Shenyang 110015
,
China) (Department of Materials Science
,
Northeastern University
,
Shenyang 110006
,
China)
金属学报(英文版)
In this paper, internal oxidation kinetics and the diffusion mechanism of oxygen in sintered Cu-Al alloy have been studied by means of scanning electron microscopy,transmission electron microscopy and heat-weighting scales. The results show that the kinetic curves obey the parabolic law in the initial stage and are linear in the late stage.The oxygen atoms are mainly transported in the from of grain boundary diffusion and volume diffusion in the process of internal oxidation. The plastic deformation of Cu matrix around oxide particles increases the probability of [O] atoms moving in accordance with dislocation diffusion mechanism. Meanwhile, the activation energy and diffusion coefficient in the process of internal oxidation are evaluated by means of kinetic method so as to obtain the velocity equations of reacting interface moving in different stage.
关键词:
: Cu-Al alloy
,
null
,
null
Author L.J. Chen1
,
2)
,
G. Yao1)
,
Z.G. Wang1) and J.F. Tian1) 1) State Key Laboratory for Fatigue and Fracture of Materials
,
Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China2) Department of Metallic Material Engineering
,
Shenyang Polytechnic University
,
Shenyang 110021
,
China Manuscript received 18 October 1998
金属学报(英文版)
The cyclic stress response and lowcycle fatigue life for wrought nickelbased superalloy GH4049 were investigated in the temperature range from 500 to 800 The relationship between the strain amplitude and the number of stress reversals was given. The behavior of cyclic hardening was observed for higher strain amplitudes at all testing temperatures and the lowcycle fatigue life generally decreased with increasing testing temperature for the same strain range. In addition, fracture surfaces of the fatigued samples were examined by using a scanning electron microscope.
关键词:
superalloy
,
null
,
null
G. Ya
,
X.Y Zhang and Y. L. Du(State Key Laboratory for Corrosion and Protection
,
Institute of Corrosion and Protection of Metals
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China)(Applied Chemistry Division of Sciences Institute
,
Shenyang Polytechnic University
,
Shenyang 110023
,
China)
金属学报(英文版)
It was proposed how the concentration distribution was calculated in the treble lager wall of hgdrogenation reactor according to the principle of hydrogen diffusion at the steady state in this paper. Based on the steady hydrogen permeation current density i∞ measund with the hydrogen probe at a given temperature, the hydmpen concentrationson the key interfaces and hydrogen distribution at any given mdial profile in the single, double or treble layer wall of hydrogenation reactor could be found by applying the presented equations throoph suitable parmeters ioput. The theoretical bases were provided for developing the nondestructive probing technique of the concentration of atomic hydmpen in the wallS of hydrogenation reactors.
关键词:
hydrogen permeation
,
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
