Z.M.Sun
,
H.Hashimoto
,
S.Sumi
,
Y.H.Park and T.Abe (Materials Engineering Division
,
Tohoku National Industrial Research Institute 4-2-1 Nigatake
,
Miyagino-ku
,
Sendai 983-8551
,
Japan) Z.H. Shan (Research Fellow of Science and Technology Agency of Japan STA)
金属学报(英文版)
Two intermetallic compounds of Ti-50at.% Al and Ti-48at.% Al-2at.% Cr were prepared with a mechanical alloying and pulse discharge sintering process. The as-sintered material showed a microstructure of equiaxed gamma grain with sub-micron size. Heat treatments in vacuum at different temperatures up to 1573K were conducted on the sintered materials. The microstructure of the material coarsened considerably after heat treatment at temperatures higher than 1523K. The mechanical properties of the as-sintered and the heat treated materials were measured at temperatures of up to 973K, with four-point bending tests. Experimental results indicated that the addition of Cr increased the fracture strength of the intermetallic compound at room temperature and at elevated temperatures as well. The bending fracture strength increased with increasing testing temperature up to about 873K and a decreasing followed up. Both fracture strength and fracture strain of the material were found to be improved by heat treatment.
关键词:
titanium aluminide
,
null
,
null
,
null
,
null
FANG Zheng CHEN Xinmin(H.M.Chen) Central South University of Technology
,
Changsha
,
China FANG Zheng
,
Associate Professor
,
Department of Chemistry
,
Central South University of Technology
,
Changsha
,
China
金属学报(英文版)
By taking the effect of oxygen contents into account,a new set of formulae which represents the oxygen potentials of H_2O-H_2 and H_2O-H_2-inerts gas mixtures has been derived.Classi- cal representation is only a particular case of it.Some of the variables affecting equilibrium atmosphere when trace oxygen is present and optimum preparation of the gas mixtures to min- imize errors have been discussed.The reliability of some of previous equilibrium experiments under the oxygen potentials controlled by H_2O-H_2 or H_2O-H_2-inerts gas mixtures has also been criticized.
关键词:
gas equilibration method
,
null
,
null
,
null
Applied Physics Letters
ZnCoO:H nanocrystals are weak ferromagnetic at room temperature with a small coercivity and a small remanence, whereas ZnCoO nanocrystals are paramagnetic. The thermal irreversibility of zero-field cooling and field cooling magnetizations of ZnCoO:H nanocrystals corresponds to the existence of superparamagnetism due to the nanosize effect. X-ray photoelectron spectra show the incorporation of Co(2+) ions inside the ZnO lattice without changing the wurtzite structure. Our data suggest that hydrogen can induce ferromagnetism in ZnCoO and that ferromagnetic ZnCoO:H crystals with small particle size can show the superparamagnetism. (C) 2008 American Institute of Physics.
关键词:
magnetic semiconductors;zno;hydrogen;cobalt
王硕明
,
丁志军
,
于恒
,
张彩军
钢铁钒钛
研究了某H型钢厂采用半敞开方式浇注的H型钢腹板裂纹产生的原因.在该厂选取了26块有代表性裂纹的试样进行了细致的研究,研究认为:H型钢腹板裂纹主要是由钢中夹杂物因素造成,通过对钢中T[O]的研究发现,中间包T[O]量平均为94×10-6,铸坯中T[O]平均为60.8×10-6,同时对比1流铸坯和2流铸坯的T[O]量变化可以发现,中间包流场分布不合理.对该厂现有的中间包进行FLUENT模拟后发现,中间包稳流器矮坝较低,不能完全消除短路流,尤其在浇注后期,矮坝损耗殆尽,基本不起作用,短路流严重,应加以优化.
关键词:
H型钢
,
裂纹
,
夹杂物
,
数学模拟
徐峰
,
何彩红
,
徐勇
钢铁研究
简述了国内H型钢的发展现状,通过列举国内典型H型钢生产线,介绍分析了轧制H型钢的1-3-1、1-3和连轧三种工艺布置,以及目前轧制H型钢的X-X和X-H两种方法.根据目前国内生产状况,提出了H型钢技术改进的几项措施.
关键词:
H型钢
,
生产工艺
,
万能轧机
X.F.Rong and Z.Y.Qin College of Mechanical Engineering
,
Taiyuan University of Technology
,
Taiyuan 030024
,
China
金属学报(英文版)
In this paper, a deposition feature of a SiC:H films deposited by a RF sputtering system and a effect on the hardness of the films with various deposition conditions are investigated, and the effects of the silicon on a C:H are studied. It follows from the results that the properties of hardness can be changed with the depositing conditions. An increase of silane in the gas phase allows to deposit a SiC:H having tetrahedral structure. The sets of deposition conditions by which the different types of a SiC:H films can be deposited are obtained.
关键词:
a SiC:H film
,
null
,
null
刘英瑞
钢铁
简述了热轧H型钢的用途,热轧H型钢与其他型钢(工字钢)在生产工艺上的不同要求,介绍了莱钢热轧H型钢(中型)生产线的工艺流程、主要设备、关键技术,以及中型型钢产品大纲中的20个规格的热轧H型钢的开发研制工艺技术要点、存在的问题和采取的措施.
关键词:
万能轧机
,
H型钢
,
研制开发
