Author C.D. Zhou1
,
2)
,
J.X. Yu1)
,
X.P. Dong1)
,
Y.H. Zhang1)
,
C.Q. Sun3) and T.F. Li4) 1) The State Education Commission Open Research Laboratory for High Temperature Materials and Testing
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China2) Shanghai Enhanced Lab of Ferrometallurgy
,
Shanghai University
,
Shanghai 200072
,
China3) Institute of Aeronautical Materials
,
Beijing 100095
,
China 4) Institute of Corrosion and Protection of Metals
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
ChinaManuscript received 18 October 1998
金属学报(英文版)
An investigation has been made on the tensile fracture behavior of oriented single crystal DD100 superalloy at 850. The appearance of the fracture surface of DD100 reflects the glide plane decohension fracture mechanism, which is different from the fracture of oriented DD100. The tensile strength and elongation are lower than the oriented DD100. Oxygen in air has little effect on the strength of DD100 but reduces the tensile elongation obviously. Oxygen does not affect the fracture mode of DD100 but strongly accelerates the process of fracture.
关键词:
single crystal superalloy
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null
,
null
H.B. Chang
,
Z.G. Li
,
T. Y. Hsu
,
Z. Y. Xu
,
and X. Y. Ruan (Department of Metallurgical Engineering
,
Shanghai Technical College of Metallurgy
,
Shanghai 200233
,
China)(Department of Plasticity Technology
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China)(Department of Materials Science
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China)
金属学报(英文版)
Proeutectoid ferrite with carbon content xo precipitating from austenite in a multicomponent steel at temperature T is supposed to be equivalent to proeutectoid ferrite with the same carbon content precipitating from austenite in Fe-C binary system at temperature T'.is described as the temperature difference of proeutectiod ferrite formation, and can be calculated from the Fe-X diagrams and the equilibrium temperature A3. By introducing Tf and basing on the thermodynamic model for Fe-C binary alloy, the driving force for phase transformation from austenite to proeutectoid ferrite in multicomponent steels has been successfully calculated. Through the Johnson-Mehl equation and using the data hem known TTT diagrams, the relationship between the chemical composition and the intedecial edenly packeter as well as activation energy for proeutectoid ferrite formation can be calculated. The starting curves of proeutectoid ferritic transformation calculated in this way in some hypo-proeutectoid structural steels agree well with the erperimental data.
关键词:
proeutectoid ferrite formation temperature difference
,
null
,
null
Z.G. Li
,
H.B. Chang
,
T. Y. Hsu
,
Z. Y. Xu
,
and X. Y. Ruan (Department of Plasticity of Technology
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China)(Department of Metallurgical Engineering
,
Shanghai Technical College of Metallurgy
,
Shanghai 200233
,
China)(Department of Materials Science
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China)
金属学报(英文版)
Supposing carbon contents of ferrite phases in pearlite precipitating from austenite in multicomponent steel at temperature T and in Fe-C ystem at T' are the same the pearlite formation temperature diference, can be calculated from the FeX phase diagrams and the equilibrium temperature Al. Using Tp and Fe-C binary thermodynamic model, the driving forces for phase transformation from austenite to pearlite in multicomponent steels have been successfully calculated. Through the combination of simplified Zener and Hillert's model for pearlite growth with Johnson-Mehl equation, using data from known TTT diagrams, the interfacial energy parameter and activation energy for pearlite formation can be determined and expressed as functions of chemical composition in steels by regression analysis. The calculated starting curves of pearlitic transformation in some commercial steels agree well with the experimental data.
关键词:
pearlite formation temperature difference
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null
,
null
W.J. Li
,
Z.M. Wu
,
J.F. Zhao
,
Z.H. Wu
,
X.L.Zhao and B.C. Cai ( Information Storage Research Center
,
Shanghai Jiaotong University
,
Shanghai 200030
,
China
,
College of Chemical Engineering & Technology
,
Taiyuan University of Technology
,
Taiyuan 030024
,
China)
金属学报(英文版)
Titanium dioxide thin films were prepared by low pressure metal organic chemical vapor deposition (LP-MOCVD) from titanium IV isopropoxide. Nitrogen was used as a carrier gas for the titanium precursor,and oxygen as a reactant gas. The deposition rates of the films have been studied as functions of process parameters such as sabstrate temperature and oxygen flow rote. Structural evolution of the films has been studied as functions of substrate temperature (110 to 700℃) and annealing temperature. The films have been characterized by X-ray dissection and by Raman scattering. Films deposited onto Si(100) substrates were amorphous at 110-250℃, anatase at 350- 550℃ and rutile above 650℃. The films deposited at substrate temperatures less than 550℃ and annealed at 600℃ for two hours were annealed, annealed at 700℃ for two hours were mixtures of anatase and rutile, and annealed at 850℃ for two hours were rutile.
关键词:
MOCVD
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null
,
null
,
null
,
null
J. T. Liu
,
H.B. Chang
,
R.H. Wu
,
T. Y. Hsu(Xu Zuyao) and X.R. Ruan( 1)Department of Plasticity Technology
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China 2)School of Materials Science and Engineering
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China)
金属学报(英文版)
The hot deformation behavior of TI (18W-4Cr-1V) high-speed steel was investigated by means of continuous compression tests performed on Gleeble 1500 thermomechan- ical simulator in a wide range of tempemtures (950℃-1150℃) with strain rotes of 0.001s-1-10s-1 and true strains of 0-0. 7. The flow stress at the above hot defor- mation conditions is predicted by using BP artificial neural network. The architecture of network includes there are three input parameters:strain rate,temperature T and true strain , and just one output parameter, the flow stress ,2 hidden layers are adopted, the first hidden layer includes 9 neurons and second 10 negroes. It has been verified that BP artificial neural network with 3-9-10-1 architecture can predict flow stress of high-speed steel during hot deformation very well. Compared with the prediction method of flow stress by using Zaped-Holloman parumeter and hyperbolic sine stress function, the prediction method by using BP artificial neurul network has higher efficiency and accuracy.
关键词:
T1 high-speed steel
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null
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null
,
null
,
null
$ D.L*
,
D.N.He
,
X.J.Bao
,
Y. Q.Zhang
,
X. Y.Ruan
,
J.L. Cheng and J. Y. Jiang 1) National Die & Mold CAD Engineering Research Center
,
Shanghai Jiaotong University
,
Shanghai 200030
,
China 2) Shanghai Volkswagen Automotive Company Limited
,
Shanghai 201805
,
China
金属学报(英文版)
With the combination of a new theoretical formula, physical simulation experiments, the technology of artificial neural network and database, an intelligent system for the prediction of sheet metal drawing capability is constructed for the first time. A modified criterion for sheet metal drawing capability is proposed in this paper, namely, the Technological Limiting Drawing Ratio, TLDR = f(R, n, s, t, F, μ,r_d,r_p…). Based on the studies of other scholars, a new formula is derived to predict the TLDR in this paper. Then a series of orthogonal physical simulation experiments are designed to investigate the effect of technological parameters on the TLDR, and the results are analyzed in the paper. Then the predicting system is constructed with the combination of the theoretical formula, orthogonal experiments, the technology of artifocial neural network and database. The predicted results show good agreements with experimental data, so it can be used to avoid the blindness in the selection of sheet metal before stamping. The system operates under the Windows operating system, and it supports the mechanism of Client/Server as well as Intranet, so the system has high engineering value.
关键词:
TLDR
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null
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null
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null
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null
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null
,
null
D. N. He
,
X. F. Yin
,
H. Z. Thao
,
D. L*
,
X. Y. Ruan
,
J. L. Cheng and J. Y. Jiang 1) Shanghai Jiao Tong University
,
National Die & Mold CAD E. R. C
,
Shanghai 200030
,
China 2) Shanghai Vopkswagen Automotive Company Ltd.
,
Shanghai 201805
,
China Manuscript received
金属学报(英文版)
The deformation characteristic of bland in deep drawing is discussed. It is pointed out that the friction and lubrication conditions in for drawing are different from that in mechanical motion or machine work or other plastic process. The common test methods in laboratories are analyzed. It shows that though all those test methods can test the friction coefficient, the probe test method is most suitable for the research of friction and lubrication and the process in deep drawing, for this method is identical with the actual work condition either from the test principle or deformation status of the blank. Last the successful application in the deep drawing simulator newly developed the the probe method are intro- duced in detail.
关键词:
deep drawing
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null
,
null
,
null
R.Shi
,
G.X.Hu
,
H.J.Li and M.K.Kang (The State Education Commission Open Research Laboratory for High Temperature Materials and Testing
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China)(Department of Materials Science and Engineering
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China)
金属学报(英文版)
The steady-state creep behavior of unidirectional C/C(1-D-C/C) composite with pyrolytic carbon matrix was investigated at high temperatures up to 2160℃ and under tensile stress from 133.83 to 213.46MPa. Based on the creep experiment of single specimen method, the apparent activation energy and the stress exponent for steadystate creep were determined by the use of a self-made apparatus and an auto-testing system. Value of apparent activation volume is provided and the creep mechanism has also been discussed.
关键词:
1-D-C/C
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null
,
null
X. G. Bao
,
D. N. He
,
D. Lu
,
C. X. Li
,
J. L. Cheng and J. Y. Jiang( 1) National Mold and Dies CAD Engineering Research Center
,
Shanghai 200030
,
China 2) Shanghai Volkswagen Automotive Company Ltd.(SVW)
,
Shanghai 201805
,
China)
金属学报(英文版)
Taking CPU time cost and analysis accuracy into account, dynamic explicit finite ele- ment method is adopted to optimize the forming process of autobody panels that often have large sizes and complex geometry. In this paper, for the sake of illustrating in detail how dynamic explicit finite element method is applied to the numerical simulation of the autobody panel forming process,an example of optimization of stamping process pain meters of an inner door panel is presented. Using dynamic explicit finite element code Ls-DYNA3D, the inner door panel has been optimized by adapting pa- rameters such as the initial blank geometry and position, blank-holder forces and the location of drawbeads, and satisfied results are obtained.
关键词:
dynamic explicit finite element method
,
null
,
null
,
null
J.M Zeng
,
H. Gu and YH. Zhou (Institute of Materials Science
,
Guangxi University
,
Nanning 530004
,
China Department of Materials Science and Engineering
,
Shanghai Jiaotong University
,
Shanghai 200030
,
China)
金属学报(英文版)
In this paper, the mathematical models for mould-filling under counteramvity are derived on the basis of the principle of momentum. Dynamic processes of mould-filling are observed on a perspex model by means of high speed photography. The results indicate that the mould-filling under counterpmvity can be described by the second oofer nonlinear dtherential equations charucterized by damping oscillations. The velocity oscillations amplofy as the pressuring speed increases if the pressure differential functions are of the same type. On the other hand, if the functions are of different type,then the velocity oscillations depend upon whether the functions pmpressively increase or decrease. Velocity oscillations can be diminished dmmatically by increasing the local damping within the gating system.
关键词:
casting
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null
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null
