SUN Xiukui CHEN Wenxiu XU Jian FAN Xueshu WEI Wenduo State Key Laboratory of Rapidly Solidified Non-Equilibrium Alloys
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Institute of Metal Research
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Academia Sinica
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Shenyang
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ChinaWU Yukun PENG Yingguo Laboratory of Atomic Imaging of Solids
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Institute of Metal Research
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Academia Sinica
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Shenyang
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China Associate Professor
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Institute of Metal Research
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Academia Sinica
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Shenyang 110015
,
China
金属学报(英文版)
The crystal habit,crystalline structure,surface condition and composition of the ultrafine Al particles prepared by inert gas evaporation method were studied in detail by means of high resolution transmission electron microscope,X-ray diffraction and X-ray photo-electron spectrum.The results indicate that the ultrafine Al particles prepared in high pure inert gas are of clear crystal habits,single crystal in a large majority and fcc crystalline structure with a_0=0.405 nm.It is also found on the surface of the Al particles that there is a layer of amor- phous Al_2O_3 with 2 nm average thickness,which could protect the particles against oxidizing further.Therefore,the ultrafine Al particles prepared by the inert gas evaporation method are very stable in atmosphere.
关键词:
ultrafine Al particle
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null
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null
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null
Chinese Physics Letters
We study the crack propagation in layered solids and find that when there exists an easy-fractured layer, the fractal surface becomes more rough, which is characterized by larger fractal dimensions.
关键词:
dimension
林鸿
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段远源
工程热物理学报
利用密度平移的方法对Peng-Robinson状态方程计算的液相密度进行了修正,给出了其描述平移量的关联式.对22种卤代烃纯物质的计算结果表明,修正后的PR方程能够很好地计算液相密度,并且能很好地再现纯物质的临界压缩因子,计算精度可以满足工程应用的需要.
关键词:
PR状态方程
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密度漂移
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卤代烃
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临界压缩因子
Advanced Materials
The key to the formation of nanocrystallites from amorphous solids lies in the annealing temperature. This aspect of the preparation of nanocrystalline materials is covered, as are other attractive features of this method, for example, that it can be applied to most alloy and pure element systems, large quantities of nanocrystalline samples can be produced, and the grain size can be controlled. The properties of these materials are also described and it is concluded that more studies on 3D bulk: porosity-free, and clean samples are needed.
关键词:
ultrafine grain-structure;alloys;selenium;sizes
Physical Review B
The pressure effect on crystallization kinetics of amorphous solids was investigated by means of thermodynamic analysis. A model was developed to describe the nucleation process under pressure by considering the crystalline/amorphous (c/a) interface that plays a dominant role in the nucleation process. Applying the model to three types of crystallization process, polymorphous (a-Se), primary (Al89La6Ni5), and eutectic (Ni80P20), we found the calculated results can give reasonable explanations for the experimental observations. The calculation suggests that for a-Se and Ni80P20 amorphous alloy, the initial stage of nucleation is a volume expansion process due to the c/a interface formation, resulting in an increase in the nucleation work with an increment of pressure. Hence the crystallization temperature of the amorphous phase rises when a pressure is applied, while for the Al-La-Ni amorphous alloy, the nucleation barrier decreases at higher pressures. The coincidence between the calculation and the experimental results illustrates that the cia interface formation is the governing factor in the crystallization kinetics of the amorphous solids. [S0163-1829(99)03534-1].
关键词:
activation volume;nanocrystalline state;metallic glasses;diffusion;alloy;selenium;phase;se;transformations;microstructure
WANG Haifeng
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ZHANG Chunxia
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QI Yuanhong
钢铁研究学报(英文版)
China is short of water seriously. But granulation of blast furnace slag (BFS) with water has many disadvantages, such as high water consumption and difficulty in heat recycling. So developing a new dry granulation technique to treat BFS is very important. The applicability of BFS directly depends on the content of non-crystalline solids in the slag after treatment. So it is of theoretical and practical significance to analyze the content of non-crystalline solids in the slag quantitatively and simply. Metallographical test is mainly adopted to quantify the non-crystalline in BFS now with the shortages such as making sample complexly, determining difficultly and personally. For the diffraction intensity of non-crystalline is proportionate to the content of non-crystalline in BFS, X-ray diffraction method was adopted to quantify the non-crystalline and the crystalline solids in BFS. The quantificational coefficient between the crystalline and the non-crystalline solids of BFS is 0.70 whose main composition is: w（CaO）38.2%，w（SiO2）35.7%，w（Al2O3）16.3%，w（MgO）8.3%. The relatively error of using X-ray diffraction instrument to quantitative analyse non-crystalline content of BFS is less than 1%.
关键词:
Blast Furnace Slag;Non-Crystalline;Crystalline;Quantificational Analysis
Journal of Non-Crystalline Solids
The formation of Fe-SiC composite, nanocrystalline solids through ball milling is reported. The effects of mechanical deformation, crystallite size and gaseous elements on the solid state reaction between Fe and SiC are also investigated. The formation of Fe3C after a long milling time is attributed to the kinetics of the reaction between nanocrystalline Fe and SiC.
关键词:
Corrosion Science
The early stages of the evolution of atmospheric corrosion of carbon steels exposed in both a laboratory simulated and a natural atmosphere environment in Shenyang have been observed by in situ scanning electron microscopy. In the case of laboratory cyclic wet-dry tests, even though the chloride content level is very low, filiform corrosion is initiated in the early stage. The filiform corrosion grows in random directions, forming a network of ridges. White nodules nucleate and grow on the ridges during continued corrosion and eventually connect with each other to form the initial corrosion scale. Pits were also found on the surface beneath corrosion products. In the case of a natural atmospheric environment, both filiform corrosion and other localized corrosion, such as pitting and inter-granular attack take place in the initial stage. It is obvious that there is variety of localized corrosion in the initial stage of atmospheric corrosion. (C) 2007 Elsevier Ltd. All rights reserved.
关键词:
steel;atmospheric corrosion;initial stage;localized corrosion;in-situ;iron;electrolyte;thickness
