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;
Solid State Communications
Samples with composition R2Fe14M3 (M = Ga and Si; R = Y, Nd, Sm, Gd, Tb, Dy, Ho, Er and Tm) have been prepared by are-melting. Crystal-structure studies have shown that the prepared samples are single phase with the rhombohedral Th2Zn17 and/or the hexagonal Th2Ni17 structure. Substitution of Ga for Fe in R2Fe17 leads to an increase of the unit-cell volume, whereas Si substitution reduces the unit-cell volume. The Curie temperatures of the R2Fe14Ga3 and R2Fe14Si3 compounds are much larger than those of the corresponding R2Fe17 compounds. The Fe moment decreases upon Ga or Si substitution. The compounds R2Fe14Ga3 and R2Fe14Si3 With R = Er and Tm exhibit a spin-reorientation transition at low temperature. (C) 1997 Elsevier Science Ltd.
关键词:
neutron-diffraction;solid-solutions;substitution;anisotropy;nd2fe17
胡海江
,
周明星
,
张益
,
王敏
,
徐光
材料与冶金学报
在Gleeble-1500热模拟机上利用热膨胀法测定了12Cr2Mo1R压力容器钢的动态连续冷却转变(CCT)曲线,观察和分析了不同冷却速度下的相变和组织,绘制了实验钢种的动态CCT曲线.实验结果表明,奥氏体变形后,铁素体和珠光体转变区向左上方移动,贝氏体转变温度降低,马氏体转变开始温度降低.
关键词:
压力容器钢
,
动态CCT曲线
,
热膨胀法
,
相变
Communications in Theoretical Physics
The unified theoretical calculation of thermal shifts (TS) of R-1 and R-2 lines and thermal broadenings (TB) of R, R' and B lines for ruby was carried out for the first time. The calculated results are in very good agreement with a great number of experimental data. Especially by using quantum theory and taking into account all the admixtures of wavefunctions within d(3) electronic configuration, all the Gamma M in electron-phonon interaction (EPI), the electronic energy spectrum and lattice-vibration Spectrum, the very important contributions to TS and TB from single-phonon direct process were theoretically calculated in detail. The microscopic essentials of various contributions are revealed, and the mistakes in previous work are remedied.
关键词:
diamond anvil cell;pressure measurement;spectroscopy;temperatures
