HUANG Qizhong
,
YANG Qzaoqin and WU Lijun(Powder Metallurgy Research institute
,
Central Sonth University of Technology
,
Changsha 410083
,
China Materials Research and Test Center
,
Hnnan University
,
Changsha 410082
,
ChinaLab. of Atomic Imaging of Solids
,
Institute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang110015
,
ChinaState Key Laboratory for Corrosion and Protection
,
Institute of Corrosion and Protection of Metals
,
Chinese Academy of Sciences
,
Shenyang 110015
,
China)Manuscript received 4 August 1995
,
in revised form 6 April 1996
金属学报(英文版)
A Preliminary study of the effect of silicon additive on the structure and properites of C-B_4C-SiC composite was conducted. A liquid Phase has formed and the liquid Si reacts with C to form SiC at the grain boundary when sintering, which accelerates the sintering process and retards the grain growth. Consequently, the density and strength of the composite increase markedly. And the increase in the density increases the oxidation resistance and decreases the specific resistance of the composite. Furthermore,the C-B_4 C-SiC composite has good heat-shock resistance. The phenomena may be dueto the strengthening and toughening of microcracks.
关键词:
:Si additive
,
null
,
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
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
,
ZHANG Chunxia
,
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:
