Papers by Author: Sang Youl Kim

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Authors: Yeong Hwan Song, Soo Han Park, Sang Youl Kim, Chang Hwan Seo, Bo Young Hur
Abstract: Al-Mg alloy foams were synthesized via conventional melt foaming method. Ca and TiH2 were introduced into molten Al-Mg alloys with different magnesium contents. The macrostructures of resultant alloy foams were analyzed and correlated with compressive properties estimated by compression test. It is shown that the pore structures observed in alloy foams degraded with increasing Mg contents. This tendency was shown to be consistent with compressive characteristics of corresponding alloy foams. In detail, plateau strength was high for Al-1wt%Mg alloy foams, exhibiting a gradual decrease in plateau strength with increasing magnesium content.
Authors: Dong Hui Yang, Sang Youl Kim, Bo Young Hur
Abstract: In this paper, the whole temperature programmed decomposition (TPD) spectrum of titanium hydride was acquired by the special designed set-up. After separating and simulating the TPD spectrum by using Spectrum Superposition Method (SSM), Consulting Table Method (CTM) and differential spectrum technique, the kinetics parameters of titanium hydride and corresponding equations were obtained. Using these kinetics equations, the fabrication parameters of Al alloy foam can be determined and foaming process of Al alloy melt can be predicted.
Authors: Sang Youl Kim, Hwan Goo Seong, Bo Young Hur
Abstract: Al foams with high porosity were fabricated via melt foaming method. In this process, Ca and TiH2 are used as thickening and foaming agent. The macrostructure of aluminum foams exhibited homogeneous distribution of fine pore sizes at shorter holding time. From comparison of the actual pore sizes with ones calculated with modified Ostwald ripening, the measured pore sizes were well fitted to the calculated ones. These results suggest that hydrogen diffusion through pore walls from smaller pores to a larger one is the main process of pore evolution at least in the later period of holding. The detailed are discussed in the context.
Authors: Jingyu Hyeon Lee, Yi Yeol Lyu, Mong Sup Lee, Jin Heong Yim, Sang Youl Kim
Abstract: Poly(methyl-co-cyclosiloxane bearing silsesquioxane)s (P(M-co-CSSQs)) were prepared. Using poly(e-caprolactone) (PCL) as a template, PCL / P(M-co-CSSQ) nanohybrid films were fabricated. The electrical, morphological, and mechanical properties of the PCL / P(M-co-CSSQ) films were investigated. The dielectric constant of a cured PCL / P(M-co-CSSQ) film at 420°C scaled down from 2.55 to 2.05 and refractive index from 1.41 to 1.33 when 20 vol. % of the PCL was admixed with the polymer matrix. The elastic modulus and hardness of the cured PCL / P(Mco- CSSQ) (2:8, vol./vol.) film were 2.50 and 0.32 GPa, respectively, showing dependency on the PCL content.
Authors: Bo Young Hur, Bu Keoun Park, Sang Youl Kim, Hoon Bae
Abstract: The uniaxial compressive test results of several aluminum foams are compared with aluminum alloy and ppi (pore per inch) of open cell foam. The compressive stress-strain curve of aluminum alloy foams exhibits universal three deformation regions: an initial linear elastic response, and then extended plateau region with a nearly constant flow stress, a final densification as collapsed cells are compacted together. The lower the foam densities are, the longer the plateau region is, but lower densities also imply lower yield stress.
Authors: Sang Youl Kim, Norbert Babcsán, Duck Kyu Ahn, Yeong Hwan Song, Bo Young Hur
Abstract: Metal foams are not easy to use as materials as their manufacturing process involves all three, solid, liquid and gaseous phases occurring simultaneously at varying temperatures and moreever the morphology of the solidified foam is quite complex. There has not been any report on the stabilization of metal foams. To compare the stabilisation of metal foams using a different method, powder metallurgy and casting method using SiC and Ca alloy particle are required. Our investigation results showed deeply etched valleys with high oxygen content and secondary phases attached to line-shaped pores with higher SiC content than the matrix. These line-shaped pores - most probably oxide bifilms-form networks decorated with either secondary phases or oxide particle. We suspect that these decorated bifilms play a crucial role in the stabilisation of metal foams.
Authors: Bo Young Hur, Sang Youl Kim, Yong Su Um, Yong Mun Ryu
Abstract: A study on the tensile, compression and bending test of Aluminum foam Application for auto bumper and rod. We know a more efficiency to adhesive Aluminum foam out side of part in aspect to price, weight and capacity when make auto-component using aluminum foam. We secured basis properties of aluminum foam for applying auto-component by tensile, compressive and bending test. Aluminum foam was equipped to crash core with different shape. The results of maximum loads test are higher by full> cavity> bridge> half type relationship order. And, we could know that a difference of weight of full, cavity, and bridge type is not big.
Authors: Bo Young Hur, Sang Hun Cho, Sang Youl Kim
Abstract: Coated sheet steels have been increasingly used in automotive industry for improving corrosion resistance. When GA outer plates processed the interfacing of the coating film and the metal matrix causes surface irregularities in the surface state of the sheet metal. Consequently, research to determine each phase composite’s friction coefficient is on-going. Investigating the effects that cause surface roughness, change and mechanical properties of outer automobile plates through temper rolling skin pass mill elongation is essential. Researching surface roughness in relation to surface friction properties requires the determination of a surface friction coefficient. This research demonstrates that there is a complex effect between the lubricant membrane and surface roughness when processing GA plates. Consequently, the strength of the lubricant membrane strongly influences the friction coefficient
Authors: Bo Young Hur, Sang Youl Kim, Kwan-Ho Song
Authors: Ki Hwan Kang, Sang Youl Kim, Yong Su Um, Bo Young Hur
Abstract: The development of mineral wool core sandwich panel depends on the reaction of resin on mineral wool and face sheet. The most important factors in developing the mineral wool core are optimization of the Curing system and density of the used resin. In addition, this product considers the functional effect and good environment instead of organic form core. This paper studied the curing conditions, the density of used resin, and the functional effect after manufacturing the mineral wool core.
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