材料期刊网

Effects of Impurity on Microstructure and Hardness in Pure Al Subjected to Dynamic Plastic Deformation at Cryogenic Temperature

F. Huang

材料科学技术（英文）

Microstructure and hardness were investigated in pure Al samples with different purities (5N: 99.999%, 4N: 99.993%, and 2N: 99.7% in weight) subjected to dynamic plastic deformation at cryogenic temperatures. The saturated sizes of refined grains/subgrains in these samples induced by plastic deformation are about 240 nm without an obvious impurity effect, but the dislocation density in 2N Al is evidently higher than that in other samples. Boundary misorientations for 5N and 4N Al are below 10° with average values of 2-3°, while the average misorientation for 2N Al is obviously larger, being about 14°. Microhardness of LNT-DPD 2N Al is higher than that of 5N and 4N Al, owing to the enhanced dislocation density as their grain/subgrain sizes are almost identical.

关键词: Aluminum

Effects of Impurity on Microstructure and Hardness in Pure Al Subjected to Dynamic Plastic Deformation at Cryogenic Temperature

F. Huang

材料科学技术（英文）

Microstructure and hardness were investigated in pure Al samples with different purities (5N: 99.999%, 4N: 99.993%, and 2N: 99.7% in weight) subjected to dynamic plastic deformation at cryogenic temperatures. The saturated sizes of refined grains/subgrains in these samples induced by plastic deformation are about 240 nm without an obvious impurity effect, but the dislocation density in 2N Al is evidently higher than that in other samples. Boundary misorientations for 5N and 4N Al are below 10° with average values of 2-3°, while the average misorientation for 2N Al is obviously larger, being about 14°. Microhardness of LNT-DPD 2N Al is higher than that of 5N and 4N Al, owing to the enhanced dislocation density as their grain/subgrain sizes are almost identical.

关键词: Aluminum

Short-time Oxidation of Alloy 690 in High-temperature and High-pressure Steam and Water

F. Huang

材料科学技术（英文）

The oxidation behavior of alloy 690 exposed to high-temperature and high-pressure steam and water at 280 °C for 1 h was investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). In high-temperature and high-pressure steam, the oxide film is composed of an outermost Ni-rich hydroxides layer, an intermediate layer of hydroxides and oxides enriched in Cr, an inner oxide layer. The film formed in high-temperature water is similar to that in steam, except for missing the Ni-rich hydroxides layer. Samples with different surface finishes (electropolished, mechanically polished, ground, and as-received) were prepared for comparison. A general increase of the oxide thickness with the degree of surface roughness is observed. The equivalent oxide thicknesses lie in the range of 100{200 nm for the as-received samples, 150{250 nm for the samples ground to 400# and 10−20 nm for the samples ground to 1500#, mechanically polished, and electropolished.

关键词: Alloy 690

马普协会煤化所和F. Schüth教授的研究活动

陆安慧

新型炭材料 doi:10.3969/j.issn.1007-8827.2003.04.014

关键词:

F-12纤维的吸湿行为

阳建红 , 董进辉 , 李海斌 , 石强 , 郭明映

复合材料学报

在60℃、80℃相对湿度90%环境条件下对F-12纤维进行了湿热老化实验,研究了长时间老化时纤维吸湿规律.通过ATR-FTIR光谱分析了湿热老化后水对F-12纤维化学结构的影响以及水在纤维中可能存在的方式,探讨了吸湿机制,实验研究了纤维单丝拉伸强度的变化,并采用SEM观察了纤维表面及拉伸断口形貌.结果表明:F-12纤维长时间的吸湿属于2阶段吸湿,吸湿初期符合Fick第二定律,后期偏离,吸湿2500 h后仍没达到平衡;水分子对F-12纤维的化学结构没有造成明显的破坏,老化2500 h后F-12纤维表面变得粗糙,出现了一些沟槽,老化后期断口呈现出脆性与原纤化复合的特征;拉伸断裂强度并非持续减小,而是在起伏波动中减小.

关键词: F-12纤维 , 吸湿规律 , ATR-FTIR , SEM , 吸湿机制 , 拉伸强度

镧系配合物f-f跃迁光谱的分析应用

杨武 , 陈淼 , 康经武 , 欧庆瑜 , 康敬万 , 高锦章

冶金分析 doi:10.3969/j.issn.1000-7571.1999.05.013

对f-f跃迁光谱在分析化学中的应用进展进行了简要的总结,详细地介绍了根据超灵敏跃迁强度变化规律测定溶液中镧系配合物的组成、形成常数及测定混合稀土中单一稀土的原理和方法.

关键词: f-f跃迁光谱 , 镧系元素配合物 , 组成测定 , 形成常数 , 综述

金红石TiO₂晶体中F和F⁺心电子结构及其吸收光谱研究

陈军 , 林理彬 , 卢铁城

无机材料学报

本文运用嵌入原子簇的电荷自治离散变分方法（SCC－DVM－Xα方法）分别对TIO₂晶体中F和F+心的能级结构进行了计算，得到了F和F⁺心的光学吸收跃迁模式，其跃迁能量分别是0.98、1.78eV.我们认为，经还原后的TiO2晶体，在光吸收实验中测到的1．2μm（1.02eV）、760um（1.75eV）两个峰分别是由于还原过程中形成的F和F⁺心的吸收峰，并存在着F→F⁺的转型过程．

关键词: F , F⁺ center , energy level , transition energy

金红石TiO2晶体中F和F+心电子结构及其吸收光谱研究

陈军 , 林理彬 , 卢铁城

无机材料学报 doi:10.3321/j.issn:1000-324X.1999.03.006

本文运用嵌入原子簇的电荷自洽离散变分方法(SCC-DVM-Xα方法)分别对TiO2晶体中F和F+心的能级结构进行了计算,得到了F和F+心的光学吸收跃迁模式,其跃迁能量分别是0.98、1.78eV.我们认为,经还原后的TiO2晶体,在光吸收实验中测到的1.2μm(1.02eV)、760nm(1.75eV)两个峰分别是由于还原过程中形成的F和F+心的吸收峰, 并存在着F→F+的转型过程.

关键词: F , F+心 , 能级结构 , 跃迁能量

小方坯高碳钢F-EMS的研究

张森林

连铸 doi:10.3969/j.issn.1005-4006.2005.01.002

小方坯F-EMS与大方坯F-EMS的电磁参数和搅拌方式有很大不同.在铸机结构受限时,通过铸机改造和提高拉速,使F-EMS安装位置接近Ds=0.7,可使82B钢种中心碳偏析平均值限制在1.06以下.

关键词:

F-P标准具间距高精度测量

王秀琳 , 黄文财 , 谢建平

量子电子学报 doi:10.3969/j.issn.1007-5461.2003.06.022

提出一种通过测量F-P标准具透射峰移动个数与F-P标准具入射角度改变的对应关系,从而求得F-P标准具间距的高精度测量方法.当角度测量精度为30",光谱仪精度为2 GHz时,该方法测量F-P标准具间距的相对误差为4×10-4.

关键词: F-P标准具 , 多光束干涉 , 光谱