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
B.K. Li
,
X.F. Ma
,
X.R. Zhang and J.C. He (Northeastern University
,
Shenyang 110006
,
China)(Northeastern University
,
Shenyang 110006
,
China)(Northeastern University
,
Shenyang 110006
,
China)(Northeastern University
,
Shenyang 110006
,
China)
金属学报(英文版)
A mathematical model for melting processes of solid particles immersed in metal baths has been develOPed, which includes the cases with the melting point of solid particles greater than, equal to, and lower than freezing point of the bath. Experiments are performed on the melting of ice spheres in water at different temperature. The model is validated by experimental data for melting of ice spheres submerged in water and aluminum spheres immersed in aluminum melt. Finally, the parometers affecting particles melting time such as particle size, bath temperature, and slip velocity are analyzed.
关键词:
mathematical model; phase change; solid particle
S.J. Zhao
,
Y.C. Wang
,
J.Q. You
,
Q.B. Yang
,
L.G. Zhou and H.Q. Ye (Department of Physics
,
Xiangtan University
,
Xiangtan 411105
,
China)(Laboratory of Atomic Imaging of Solids
,
Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China)(Department of Materials Science
,
Northeastern University
,
Shenyang 110006
,
China)
金属学报(英文版)
A structural transition in the fcc ∑=5 (120)/[001] high-angle tilt grain-boundary(GB)is investigated by molecular-dynamics simulation. The calculations have been performed at various temperutures and the thermodynamic melting point Tm of the model system is determined by using a many-body potential fitted to copper. A thermal disorder transition in the GB region occurs well below the melting point. Our results indicate that such a transition is a continuous process and there is no evidence of premelting, which is entirely in accord with experiment results and theoretical prediction.Moreover we also observed that melting initiated at the interface and then propagated into the bulk quickly at or above Tm.
关键词:
moleculandynamics
,
null
,
null
WU Zhixue
,
LU Wenge and XU Hao1)(Fushun Petroleum institute
,
Fushun 113001
,
China)2)(State Key Laboratory for Fatigue and Fracture of Materials
,
Institute of Metal Research
,
ChineseAcademy of Sciences
,
Shenyang 110015
,
China)3)(Institute of Mechanical Engineering
,
Northeastern University
,
Shenyang 110006
,
China)Manuscript received 19 July 1995
,
in revised form 11 April 1996
金属学报(英文版)
Rotary bending fatigue tests were carried out for smooth specimens of a mediumcarbon steel with two different grain sizes near the fatigue limit. The process of fatigue damagewas observed by replication method, and the effects of grain size,stress level and microstructure on surface damage were studied. The effect of following cycle stress level on the coaxing effects was also discussed. The fatigue limit is the maximum stress at which the short fatigue crack initiates and becomes a non-propagating crack.. The length of non-propagating crack is related to grain sizes and stress level. The coaxing effects disappear when the following stress level is greater than the critical value.
关键词:
: fatigue damage
,
null
,
null
S. W Ma
,
J.C
,
He and H.S. Di 1) School of Materials and Metallurgy
,
Northeastern University
,
Shenyang 110006
,
China 2) The State Key Laboratory of Rolling and Automation
,
Northeastern University
,
Shenyang 110006
,
China
金属学报(英文版)
In this paper three-dimensional flow field in the molten pool between unequal diameter twin rolls has been studied by BFC technology and SIMPLEC numerical method. From the computed flow pattern,the characteristic of molten steel flow has been discussed. The dynamics generated by the feeding flow and the motivation of counter-rotating twin rolls produces a recirculating flow field nearby the small roll due to the larger room and less resistant here and fluid flows along the roll surface tangential nearby large roll and extends to two side dams. There is faintly flow around the dams of molten pool
关键词:
NNSCC
,
null
,
null
,
null
,
null
P. Zhang
,
J.Z. Cui
,
Y.H. Du and Q.Z. Zhang(Department of Metal Forming
,
Northeastern University
,
Shenyang 110006
,
China)(Department of Mining
,
Northeastern University
,
Shenyang 110006
,
China)
金属学报(英文版)
Artificial neural networks (ANN), being a sophisticated type of information processing system by imitating the neural system of human brain, can be used to investigate the effects of concentration of flux solution, temperature of liquid aluminium, temperture of tools and pressure on thickness of the intermetallic layer at the interface between steel and aluminium under solid-liquid pressure bonding of steel and aluminium perfectly. The optimum thickness has been determined according to the value of the optimum shearing strength.
关键词:
artificial neural network
,
null
,
null
Z.H.Jiang 1)
,
Y.He 2)
,
X.L.Jiang 1)
,
G.J.Han 1) and S.S.Rui 1) 1) Department of Iron & Steel Metallurgy
,
School of Material and Metallurgical Science
,
Northeastern University
,
Shenyang 110006
,
China 2) Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China
金属学报(英文版)
The thermal conductivities of different typical species filling materials for sliding gate systems for steel ladles were measured using a hot wire technique, and the relationships between thermal conductivity and temperature were regressed. The factors affecting thermal conductivity were analyzed by using variance analysis for a perpendicular experiment. The effects of thermal conductivity on sliding gate free tapping were studied, and it was revealed that decreasing the thermal conductivity of the filling materials is beneficial in enhancing the rate of free tapping for sliding gates.
关键词:
filling materials
,
null
,
null
,
null
T.L. Wang 1
,
2)
,
J.T. Guo 1)
,
D.S. Xia 2)
,
Y.Wang 1) and H.C. Yang 2) 1) Institute of Metal Research
,
Chinese Academy of Science
,
Shenyang 110015
,
China 2) Material and Metallurgical Institute Northeastern University
,
Shenyang 110006
,
China
金属学报(英文版)
Effect of revert cycles on microstructure and fatigue properties of cast cobalt base superalloy K640S has been investigated. The results show that: at 70 times of cool heat cycles, there were microcracks found in seven times revert and ten times revert. With the increasing of thermal fatigue cycles, the crack of revert grows a little faster than virgin. When the cycle time reaches 200, the crack length for both virgin and reverts have been as long as 2mm. The low cycle fatigue life has no remarkable change, with the increase of revert cycles at 815℃, 360MPa ,0 5Hz. With the times of cycles increasing, it is found that the content of impurity and gas in alloy change a little, and there is no obvious change for dendrite microstructure.
关键词:
revert
,
null
,
null
,
null
,
null
DU Hegui
,
ZOU Anhua
,
Northeast University of Technology
,
Shenyang
,
China Du Hegui
,
Professor
,
Department of Ferrous Metallurgy
,
Northeast University of Technology
,
Shenyang 110006
,
China
金属学报(英文版)
A study was carried out on the formation of Ti(C,N) during smelting vanadium-bearing titanomagnetite in blast furnace and the influence of MnO content on reduction of TiO_2 in the slag containing high titania. The reduction of TiO_2 is restricted by MnOpredominantly at the slag-metal interface and no more at the slag-coke one. The formation of Ti(C,N) is remarkably restricted by MnO in the slag when the MnO content is about 4% and the basicity from 0.6 to 1.2 in the slag. MnO may also retards the reduction of SiO_2 and accelerates the desulphidation under certain condition.
关键词:
blast furnace smelting
,
null
,
null
,
null
,
null
S. Abubakir
,
Y.S. Wu
,
T.C. Zhang
,
Z. Yang and Z. Zhang (Department of Surface Science & Corrosion Engineering
,
University of Science and Technology Beijing
,
Beijing 100083
,
China)(Department of Materials Science and Engineering
,
Northeastern University
,
Shenyang 110006
,
China)
金属学报(英文版)
Samples of FJ316 stainless steel powder alloyed with different amounts of glass2 material have been compacted at the pressure of 686MPa and sintered at 1160, 1180,and 1200℃, in hydrogen atmosphere for one hour. The materials have been subjected to microstructure characterization, tensile strength, handness, impact toughness and corrosion testing. The effect of the experimental process parameter has been evaluated and the importance of porosity, sintered temperature, glass content and its grain size in determining mechanical and corrosion properties has been confirmed. Glass has a strong effect on the mechanical properties and produces brittleness when added to FJ316SS. Very good corrosion resistance has been achieved by comparing this result with the corosion resistance of sintered pure stainless steel. The results of this study permit optimization in the production of glass alloyed P/M FJ316SS, with respect to mechanical properties and high corrosion resistance.
关键词:
corrosion rate
,
null
,
null
,
null
,
null
