R.C.Yang
,
K.Chen
,
H.X.Feng
,
H.Wang
金属学报(英文版)
The observations of dislocations， substructures and other-microstructural details were conducted mainly by means of transmission electron microscope (TEM) and scanning electron microscope (SEM) for 12Cr1MoV pearlitic heat-resistant steel. It is shown that during the high temperature long-term aging, the disordered and jumbled phasetransformed dislocations caused by normalized cooling are recovered and rearranged into cell substructures, and then the dislocation density is reduced gradually. Finally a low density linear dislocation configuration and a stabler dislocation network are formed and ferritic grains grow considerably.
关键词:
pearlitic heat-resistant steel
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null
X.Yao
,
C.Z.Wu
,
H.Wang
,
H.M.Cheng
,
G.Q.Max Lu
材料科学技术（英文）
Hydrogen storage in traditional metallic hydrides can deliver about 1.5 to 2.0 wt pct hydrogen but magnesium hydrides can achieve more than 7 wt pct. However, these systems suffer from high temperature release drawback and chemical instability problems. Recently, big improvements of reducing temperature and increasing kinetics of hydrogenation have been made in nanostructured Mg-based composites. This paper aims to provide an overview of the science and engineering of Mg materials and their nanosized composites with nanostructured carbon for hydrogen storage. The needs in research including preparation of the materials, processing and characterisation and basic mechanisms will be explored. The preliminary experimental results indicated a promising future for chemically stable hydrogen storage using carbon nanotubes modified metal hydrides under lower temperatures.
关键词:
Hydrogen storage
,
null
,
null
,
null
,
null
,
null
L.Z.Ouyang
,
C.Y.Chung
,
M.Q.Zeng
,
H.Wang
,
M.Zhu
金属学报(英文版)
Mg-Ni thin films for nickel-metal hydride(Ni-MH) battery negative electrode were prepared on three different substrates by using magnetron sputtering with compacted Ni and Mg mixture powder.The microstructure of Mg-Ni thin films deposited on the glass and the Ni foil substrate respectively was studied by X-ray diffraction(XRD) and scanning electron microscopy(SEM).The results show that the Mg-Ni thin films were in amorphous structure and the composition of the thim film was homogeneous.Electrochemical measurement show the discharge capacity of the thin film negative electrode deposited on the foam Ni substrate was 234.8mAh/g in 6M alkaline electrolyte and the internal resistance was much lower than that of the electrode prepared by the ball-milled powder during the charge-discharge cycle.
关键词:
magnetron sputtering
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null
,
null
R.C.Yang
,
K.Chen
,
H.X.Feng
,
H.Wang
金属学报(英文版)
Based on the analysis and processing on relative empirical formula and data, C-values in Larson-Miller (P) expression, P = T(C + lgt), have determined for pearlitic heat resistant steel 12Cr1Mo V and 15 CrMo (20. 62 and 20. 30). The simulation experiments of high temperature aging, heated from 1.5 to 873 hours, have been designed and performed for its verification. And in combination with published information and the present nearly quantitative works, it has further been verified that both the degradations of microstructures and mechanical properties show a good accuracy and practicability using the Larson-Miller parameter with the present determined C-values. Finally, the effects of carbon content on C-value are analyzed by the empirical electron theory of solids and molecules (EET).
关键词:
pearlitic heat-resistant steel
,
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
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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
