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Yang, Tae-Young;Cho, Yong-Ki;Kim, Young-Woo;Yoon, Seog-Young;Park, Hong-Chae
- Journal of the Korean Ceramic Society
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- v.45 no.2
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- pp.99-104
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- 2008
Zeta potential, sedimentation bulk density and rheology in the dispersion system have been studied in terms of solid loading (40-55 vol%), and types of additives. Ammonium polymethacrylate, glycerol, ethoxylated acetylenic diol, and polyvinyl alcohol have been used as the dispersant, cryo-protectant, surfactant, and binder, respectively. Sedimentation density greatly increased upon adding dispersant; the effect was more pronounced with ionic alumina suspension compared with covalent silicon carbide. With further addition of cryo-protectant and surfactant to dispersant, the sedimentation density increased somewhat. The suspension viscosity generally behaviored in an opposite manner to the sedimentation density, i.e., high sedimentation gave low high-shear viscosity, indicative of low order structure formation in the suspended particles. Shear rate rheology in shear rate of $2-300\;sec^{-1}$ showed a shear thinning and its onset began at similar shear rate (${\sim}100\;sce^{-1}$), regardless of solid loading.
https://doi.org/10.4191/KCERS.2008.45.2.099 인용 PDF KSCI

Kwon, K.Y.;Kang, C.G.
- Transactions of Materials Processing
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- v.18 no.1
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- pp.26-38
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- 2009
It was reported that the semi-solid forming process has many advantages over the conventional forming process, such as a long die life, good mechanical properties and energy savings. It is very important, however, to control liquid segregation to gain mechanical property improvement of materials. During forming process, rheology material has complex characteristics, thixotropic behavior. Also, difference of velocity between solid and liquid in the semi-solid state material makes a liquid segregation and specific stress variation. Therefore, it is difficult for a numerical simulation of the rheology process to be performed. General plastic or fluid dynamic analysis is not suitable for the behavior of rheology material. The behavior and stress of solid particle in the rheology material during forging process is affected by viscosity, temperature and solid fraction. In this study, compression experiments of aluminum alloy were performed under each other tool shape which is rectangle shape(square array), rectangle shape(hexagonal array), and free shape tool. In addition, the dynamics behavior compare with Okano equation to power law model which is viscosity equation.
https://doi.org/10.5228/KSPP.2009.18.1.026 인용 PDF KSCI

강충길
- Transactions of Materials Processing
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- v.11 no.2
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- pp.123-131
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- 2002
The rheology process is net shape manufaturing technology to high of automobile part and improve the mechanical properties. For the rheology forming process, Phase and globular microstructure are very important. The equipments to make a rheology alloys with slurry statement have been introduced. Therefore, the Problems to Produce a rheology alloyas with continuous process had also been investigated to make Production in industries. The validity of the introduced rheology Process is investigated by comparing the reported thixoforming results. Therefore, the many advantage of rheology process to be reduced the reheating Process and billet fabrication method has been expressed in terms of mass production, in the future.
https://doi.org/10.5228/KSPP.2002.11.2.123 인용 PDF KSCI