吕忆城
,
M.R.Notis
,
J.I.Goldstein
金属学报
本文研究了淬火冷却过程中Cu:Cu-Al扩散偶α/β界面的逆向迁移,α/β界面的变温扩散模型在Fick第二定律基础上用数值分析法进行了计算.界面逆向迁移的距离和下列因素有关:高温时的原始浓度分布、扩散温度、扩散系数、冷却速率和相图中溶解度曲线的斜率.“界面逆向迁移效应”还影响了浓度分布曲线的形状和界面浓度.
关键词:
吕忆城
,
M.R.Notis
,
J.I.Goldstein
金属学报
用“双套管法”淬火测定Cu:Cu-Al扩散偶中的相平衡,由于该法具有较快的冷却速度,保证了α/β相界面处于局部平衡.传统的淬火方法冷速通常是不够快的,不足以抑制β相的分解.较慢的冷却使界面形貌发生改变;测出的界面浓度是较低温度下的数值.有理由相信,Eifert等实验得到的各温度下都远较平衡浓度为高的α/β相界浓度,是由于实验过程中较慢的冷速所导致.
关键词:
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
