V Sajadi Far
,
M Ketabchi
,
M R Nourani
钢铁研究学报(英文版)
The 34CrMo4 (American grade: AISI 4130) steel is extensively utilized in the compressed natural gas cylinders. Due to the importance of thermo-mechanical processing in the production of these cylinders, the dynamic recrystallization (DRX) characteristics of 34CrMo4 steel were investigated in the present study. In the present work, the effect of hot deformation parameters such as temperature and strain rate on the dynamic restoration processes of a 34CrMo4 alloy was studied. Hot compression tests were performed in the temperature range of 900-1100?C and the strain rate range of 0.001-0.1 s??. Hot workability of this alloy has been analyzed by employing flow localization parameter. The flow curves observed are typical of occurrence of dynamic recrystallization and have exhibited single or multiple peak in flow stress before reaching steady state, depending on the temperature and strain rates. The flow stress decreases with the increase of deformation temperature and the decrease of strain rate. Finally the activation energy obtained in this research is 490.749kj/mol.
关键词:
34CrMo4 steel;hot deformation;activation energy;dynamic recrystalization;
Pohkok Ooi
材料科学技术（英文）
Polarized far infrared (FIR) reflectance technique was applied to study the optical properties of a bulk wurtzite zinc oxide (ZnO) single crystal. Room temperature polarized FIR reflectance spectra were taken at various angles of incidence, from 20° to 70°. The theoretical polarized FIR reflectance spectra were simulated based on the anisotropic dielectric function model. Good agreement was achieved between the experimental and the theoretical FIR reflectance spectra. Through this work, a complete set of reststrahlen parameters of a bulk wurtzite ZnO at the Brillouin zone centre was obtained. Additionally, other FIR optical properties such as the real and the imaginary parts of the complex dielectric function, real and imaginary parts of the refractive index, the absorption coefficient and the reciprocal of the absorption coefficient were also obtained by using numerical calculation.
关键词:
Zinc oxide
ZHONG Jiaxiang ZHENG Xiuhua XU Zongrui Beijing Institute of Technology
,
Beijing
,
ChinaBAI Dezhong Nei Monggol Machine Works No.2
,
Nei Monggol
,
China Beijing Institute of Technology
,
Beijing 100081
,
China
金属学报(英文版)
Three types of alloy carbides have been observed in tempered steel 4335V:M_3C,M_7C_3 and M_4C_3.The precipitation temperatures are 200—700,400 and 500 ℃ respectively.The com- position,morphologies and distribution patterns of the carbides as well as the relationship be- tween them and as-quenched substructures have been investigated.The influence of the car- bides on the low temperature impact toughness of the steel has also been discussed.
关键词:
steel 4335V
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null
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null
