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
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null
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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
,
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
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null
