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
,
null
,
null
,
null
,
null
W Liang~1
,
2)
,
Q. Li~2) and D.ZYang~2)(Centre of Measuring and Testing Taiyuan University of Technology
,
Taiyuan 030024
,
China Institute of Materials Science and Engineering
,
Harbin Institute of Technology
,
Harbin 150001 China Manuscript received 13 November 1995)
金属学报(英文版)
An in situ study of twinning at crack tip in a TiAl-base alloy has been performed.The result shows that twinning with long shear vector(2/6) [112] can generate on(111) plane, even though usually it is very difficult to occur because of the high energy barrier. It was further shown that (1/6) [112](111) twinning is considerably easier to generate. Furthermore,(1/2)<110) ordinary dislocations were very active and dominated nearly the whole plastic zone, in spite of low Schmid factors. On the other hand, however <101) and (1/2) <112] superdislocations with higher Schmid factors can hardly be observed.
关键词:
:TiAl-base alloy
,
null
,
null
M. Guan
,
J. L. song and H. G. Guo Taiyuan Heavy Machinery Institute
,
Taiyuan 030024
,
China
金属学报(英文版)
In the hot forming of Mn18Cr18N steel, such problems as easy cracking, difficult controlling of forming paramenters often occur. In this paper,the variation rule of the plasticity of the steel, the starting mechanism of micro-crack and its generating characteristics were studied with the combination of thermodynamic simulation test, micro-simulation and FEM, the related data of microstructure change and hot forming parameters were produced. The hot forming process of 600MW generator retaining ring was analyzed as an example.
关键词:
Mn18Cr18N
,
null
,
null
X.H. You
,
Q.L. Zhang and H.G. Guo Taiyuan Heavy Machinery Institute
,
Taiyuan 030024
,
China
金属学报(英文版)
The significance of this paper lies in the application of bending-upsetting 35CrMo steel in train crack-shaft. The hot deforming tests of 35CrMo steel have been done on the Gleeble-1500 testing machine with the deformation temperature at the range of 900癈-1250癈, a strain strain of 0.05 s-1, 0.5 s-1, 1.0 s-1 and compress degree of 15%-80%. Through respectively analyzing and studying the microstructure of the specimen and getting the data from the testing, the results obtained are as follows: the model of flow stress and the stress-strain relationship of material hot deformation, the model of dynamic and static re-crystallization and the correlative references of hot forming parameters and changes of microstructure. The hot deforming stress-strain curses and relevantly re-crystallized micro-structure of 35CrMo steel are drawn at the deformation temperature of 1250 and the strain rate of 1.0 s. Through analyzing and regressive calculating the grain size of the deformation specimen of 35CrMo steel at different locations under the large-deformation and high-temperature conditions, the hot-deforming model of grain calculation is verified. The experimental results and the model of grain calculation can provide scientific basis for analyzing the hot deformation processes and controlling quality.
关键词:
35CrMo steel
,
null
,
null
