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Chen B.,Guizhou University | Wu Y.J.,China Institute of Technology | Zhu T.,Guizhou University | Li X.Y.,Guizhou Province Special Functional Materials 2011 Collaborative Innovation Center | Li X.Y.,GuiZhou Yonghong Aviation Machinery Co.
Advanced Materials Research | Year: 2014

The solution treatment of 6063 aluminum alloy was carried out and the influences of solution process on microstructure, strength, hardness, and electrical resistivity of 6063 aluminum alloy was analyzed. The result shows that the suitable solution treatment can improve alloy solution-degree fully, meanwhile the changes of electrical resistivity of alloy tend to be balanced. The suitable solution process for 6063 aluminum alloy is solution-treated at 520°C for 3.5h, and the strength and hardness of alloy can be enhanced extremely after aging-treatment at 200°C for 5h. © (2014) Trans Tech Publications, Switzerland.


Li Z.,Guizhou Institute of Metallurgy and Chemical Enginering | Zhao W.,Guizhou Institute of Metallurgy and Chemical Enginering | Gu W.,Guizhou Institute of Metallurgy and Chemical Enginering | He H.,Guizhou Institute of Metallurgy and Chemical Enginering | And 2 more authors.
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2010

In order to study the effect of Ti on microstructure and properties of Co-based alloy coating, Co-based alloy and Ti/Co-based alloy composite coatings are obtained on low carbon steel surface by 5 kW CO2 laser. Microstructure, microhardness, and sliding wear resistance of the coatings are studied. The results show that Co-based alloy coating consists of γ-Co, ε-Co, Cr23C6 and Ti/Co-based alloy composite coating consists of γ-Co, ε-Co, Cr23C6, TiC and so on. The Co-based alloy coating is made up of flourishing γ-Co dendrite and eutectic structure. Equiaxed solid solution and fine eutectic structure are observed in the Ti/Co-based alloy composite coating. The influence of in-situ synthesis TiC particles on microstructure of coating is prominent. And the microstructure is refined by changing it from dendrited to equiaxed grain by TiC.


Yu D.,CAS Institute of Engineering Thermophysics | Yu D.,University of Chinese Academy of Sciences | Yu D.,Wuxi Heat Exchanger Engineering Research Center | Hu X.,CAS Institute of Engineering Thermophysics | And 17 more authors.
Applied Thermal Engineering | Year: 2013

A micro particle image velocimetry (micro-PIV) system was used to investigate the shape of the meniscus and the flow characteristics in open rectangular microgrooves heat sinks. In experiment, the rectangular microgrooves heat sinks were placed in horizon, the inclined angle of 15, 25 and 35. The results show that the shape of meniscus in rectangular microgrooves heat sinks in horizon, the inclined angle of 15, 25 and 35 with input heat flux is parabolic. At low heat flux, the shape of meniscus in horizontal microgrooves heat sink could be regarded unchanged and never touches bottom of the microgrooves; in inclined microgrooves, the bottom of the shape of meniscus gradually moves downward to the microgroove bottom. Flow stages in rectangular microgrooves heat sinks verify the assumption that there exist continuous accommodation stage and corner flow stage. The mean curvature of meniscus in horizontal microgrooves almost does not change along axial direction of microgrooves. The mean curvature of the meniscus increases along the axial direction of inclined microgrooves heat sinks. Velocity decreases from the middle to both of the side walls. The mean velocity profile is not symmetrical, and this is due to the different roughness of two side walls. © 2013 Elsevier Ltd. All rights reserved.


Zhao F.,Guizhou University | Zhao F.,Guizhou Province Key Laboratory of Structure and Strength of Materials | Chen Z.-S.,Guizhou University | Chen Z.-S.,Guizhou Province Key Laboratory of Structure and Strength of Materials | And 2 more authors.
Cailiao Kexue yu Gongyi/Material Science and Technology | Year: 2011

The aluminum vacuum brazing technique has significant effect to the microstructure and property of the welded joint, the massive existence of Si segregation is the primary problem. The microstructures of the welding joint under 15 min-90 min six different holding times and 595°C-620°C six different holding temperatures are analyzed by means of micro-hardness, optical microscope, scanning electron microscope. Experimental results obtained show that along with the welding holding time's extension and holding temperature's enhancement, Si element proliferation between welded joint's is getting more and more full, the original dendritic shape of the Si segregation turns to the globular shape. When the holding time is 75 min and the holding temperature is 615°C, there is only a little Si segregation in the welded joint, the major part is the solid solution, the filler metal has the few corrosions to the parent metal, the welding is more reliable.


Yu D.,CAS Institute of Engineering Thermophysics | Hu X.,CAS Institute of Engineering Thermophysics | Guo C.,CAS Institute of Engineering Thermophysics | Tang D.,CAS Institute of Engineering Thermophysics | And 4 more authors.
ASME 2013 11th International Conference on Nanochannels, Microchannels and Minichannels, ICNMM 2013 | Year: 2013

This paper presents the experimental investigation on shape of the meniscus in cross sections along the axial direction of open rectangular microgrooves heat sinks with input heat flux under pure evaporation heat transfer condition. The images of the shape of the meniscus in rectangular open microgrooves heat sinks were recorded by a CCD camera with the speed of 10 frames per second. Microgrooves heat sinks were placed in four inclined angles, horizon, inclined 15 degrees, inclined 25 degrees and inclined 35 degrees, and heat flux is 0.09W/cm2, 0.14 W/cm2 and 0.25 W/cm2. The results show that the shape of the meniscus is parabolic not round. When the microgrooves heat sinks are placed horizontally, the shape of the meniscus and the curvature of the meniscus in cross sections changes little along the axial direction of the microgrooves. When the microgrooves heat sinks were placed inclined 35 degrees, the meniscus moves downward to the microgroove bottom. At the same distance to the reservoir and the same heat flux, the curvature of the meniscus in inclined 35 degrees is larger than that in inclined 25 degrees, and similarly, the curvature of the meniscus in inclined 25 degrees is larger than that in inclined 15 degrees. While at the same heat flux, the microgrooves heat sink is placed in inclined 35 degrees, the curvature of the meniscus increases with the increase of the distance to the reservoir. Copyright © 2013 by ASME.

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