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
WANG Bowen
,
WU Changheng
,
ZHUANG Yuzhi
,
JIN Ximei
,
LI Jingyuan(Institute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang 110015
,
China)(Shenyang Institute of Technology
,
Shenyang 110023
,
China)(Institute of Physics
,
Chinese Academy of Sciences
,
Beijing 100080
,
China)
金属学报(英文版)
The structure and magnetostriction of R(Fe_(1-x)Al_x)_y alloys(R=Dy_(0.65)Tb_(0.25)Pr_(0.1),x≤0.3,y=1.8 and 2) have been investigated using metallography, X-ray diffraction, electron probe micro- analysis(EPMA) and standard strain gauge techniques.It was found that the matrix of R(Fe_(1-x)Al_x)_2 alloys is cubic Laves phase(Dy,Tb,Pr)(Fe,Al)_2 and the second phase is PuNi3-type (Dy,Tb,Pr)(Fe,Al)_3 when x<0.15.The R(Fe_(1-x)Al_x)_(1.8) alloys contain trace of rare earth-rich phase.The magnetostriction of R(Fe_(1-x)Al_x)_y alloys decreases with increasing x in high magnetic fields; however, it exhibits a peak when x = 0.05 in low magnetic fields(H≤ 160 kA / m).The magnetostriction of R(Fe_(1-x)Al_x)_(1.8) alloys is higher than that of R(Fe_(1-x)Al_x)_2 alloys when x<0.15.
关键词:
:rare earth-iron alloy
,
null
,
null
Z. Liu
,
Y. Y. Xu
,
Z.G. Wang
,
Y. Wang
,
and Z. Y. Liu State Key Laboratory for Fatigue and Fracture of Materials
,
Institute of Metal Research
,
Tile Chinese Academy of Sciences
,
Shenyang 110015
,
China School of Material Science and Engineering
,
Shenyang Technical University
,
Shenyang 110023
,
China
金属学报(英文版)
Fully reversed total strain-controlled low-cycle fatigue tests were conducted at room temperature in air to study fatigue behavior of AZ91HP in as high pressure die casting and subsequently heat treatments. All the specimens in different heat histories exhibited cyclic strum hardening in different degrees. It was difficult to distinguish the fatigue behaviors of the die-casting specimens from the solution-aging specimens. However the solution treated specimens showed longerfatigue life at high strum amplitude and shorter fatigue life at low strain amplitude than die-casting and the solution-aging specimens though they had the lowest yield strength with higher strain hardening. Fatigue fracture surfaces for strain amplitude larger than 0.005 showed very similar to those of the monotonic tensile tests. The SEM examination revealed that regions of fatigue crack growth and final fracture could be characterized by quasi-cleavage mech anisms, but some shallow dimples, slip bands and secondary cracks were found on the fracture surface in the fracturs crack growth areas.
关键词:
low-cycle fatigue
,
null
,
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
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
