Journal of Powder Materials

Eon-Sik Lee

4 Articles

Densification and Nanocrystallization of Water-Atomized Pure Iron Powder Using High Pressure Torsion: Eun-Yoo Yoon, Dong-Jun Lee, Ha-Neul Kim, Hee-Soo Kang, Eon-Sik Lee, Hyoung-Seop Kim; J Korean Powder Metall Inst. 2011;18(5):411-416.; DOI: https://doi.org/10.4150/KPMI.2011.18.5.411

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In this study, powder metallurgy and severe plastic deformation by high-pressure torsion (HPT) approaches were combined to achieve both full density and grain refinement at the same time. Water-atomized pure iron powders were consolidated to disc-shaped samples at room temperature using HPT of 10 GPa up to 3 turns. The resulting microstructural size decreases with increasing strain and reaches a steady-state with nanocrystalline (down to ~250 nm in average grain size) structure. The water-atomized iron powders were deformed plastically as well as fully densified, as high as 99% of relative density by high pressure, resulting in effective grain size refinements and enhanced microhardness values.

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Analyses of Densification and Consolidation of Copper Powders during High-Pressure Torsion Process Using Finite Element Method
Dong Jun Lee, Eun Yoo Yoon
Journal of Korean Powder Metallurgy Institute.2015; 22(1): 6. CrossRef
Microstructure Evolution and Mechanical Properties of Al-1080 Processed by a Combination of Equal Channel Angular Pressing and High Pressure Torsion
Mohamed Ibrahim Abd El Aal, Eun Yoo Yoon, Hyoung Seop Kim
Metallurgical and Materials Transactions A.2013; 44(6): 2581. CrossRef
Trend in Research of Powder Consolidation Using Severe Plastic Deformation
Eun Yoo Yoon, Dong Jun Lee, Dong-Hyun Ahn, Hyuk Jae Jeong, Hyoung Seop Kim
Journal of Korean Powder Metallurgy Institute.2013; 20(2): 148. CrossRef
Ultrafine Grained Cu-diamond Composites using High Pressure Torsion
Eun-Yoo Yoon, Dong-Jun Lee, Taek-Soo Kim, Hyoung-Seop Kim
Journal of Korean Powder Metallurgy Institute.2012; 19(3): 204. CrossRef
Densification of Copper Powders using High-pressure Torsion Process
Dong-Jun Lee, Eun-Yoo Yoon, Soo-Young Kang, Jung-Hwan Lee, Hyoung-Seop Kim
Journal of Korean Powder Metallurgy Institute.2012; 19(5): 333. CrossRef

Quantitative Analysis of Roughness of Powder Surface Using Three-Dimensional Laser Profiler and its Effect on Green Strength of Powder Compacts: Dong-Jun Lee, Eun-Yoo Yoon, Ha-Neul Kim, Hee-Soo Kang, Eon-Sik Lee, Hyoung-Seop Kim; J Korean Powder Metall Inst. 2011;18(5):406-410.; DOI: https://doi.org/10.4150/KPMI.2011.18.5.406

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Green strength is an important property of powders since high green strength guarantees easy and safe handling before sintering. The green strength of a powder compact is related to mainly mechanical and surface characters, governed by interlocking of the particles. In this study, the effect of powder surface roughness on the green strength of iron powders was investigated using a transverse rupture test. Three-dimensional laser profiler was employed for quantitative analyses of the surface roughness. Two different surface conditions, i.e. surface roughness, of powders were compared. The powders having rough surfaces show higher green strength than the round surface powders since higher roughness leads increasing interlocked area between the contacting powders.

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A Study on the Carbon Composite Briquette Iron Manufacturing Using Fe-containing Process Wastes
Jong Yeong Yu, Dae Young Yang, Hee Dong Shin, Il Sohn
Journal of the Korean Institute of Resources Recycling.2015; 24(3): 34. CrossRef
Obtaining Mechanical Properties of Fe Powder Using a Combined Nanoindentation and the Finite Element Method
Hyeok Jae Jeong, Dong Jun Lee, Eun Yoo Yoon, Eon Sik Lee, Nack Joon Kim, Hyeong Seop Kim
Journal of Korean Powder Metallurgy Institute.2013; 20(4): 280. CrossRef

Effect of Particle Size on Compactibility of Water-atomized Pure Iron Powder: Dong-Jun Lee, Eun-Yoo Yoon, Ha-Neul Kim, Hee-Soo Kang, Eon-Sik Lee, Hyoung-Seop Kim; J Korean Powder Metall Inst. 2011;18(3):221-225.; DOI: https://doi.org/10.4150/KPMI.2011.18.3.221

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In the current study, the effects of particle size on compaction behavior of water-atomized pure iron powders are investigated. The iron powders are assorted into three groups depending on the particle size; 20-45 µM, 75-106 µM, and 150-180 µM for the compaction experiments. The powder compaction procedures are processed with pressure of 200, 400, 600, and 800 MPa in a cylindrical die. After the compaction stage, the group having 150-180 µM of particle size distribution shows the best densification behavior and reaches the highest green density. The reason for these results can be explained by the largest average grain size in the largest particle group, due to the low plastic deformation resistance in large grain sized materials.

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Preparation of high-purity reduced iron powder by Höganäs process from ultra-pure magnetite concentrate
Jin-tian Wu, Bin Xu, Zhong-lin Dong, Yu-juan Zhou, Liang-ping Xu, Guang-hui Li, Tao Jiang
Journal of Central South University.2023; 30(9): 3006. CrossRef
Hydrogen Reduction Behavior of Oxide Scale in Water-atomized Iron Powder
Hea-Min Shin, Kyeong-Ho Baik
Journal of Korean Powder Metallurgy Institute.2014; 21(6): 422. CrossRef
Quantitative Analysis of Roughness of Powder Surface Using Three-Dimensional Laser Profiler and its Effect on Green Strength of Powder Compacts
Dong-Jun Lee, Eun-Yoo Yoon, Ha-Neul Kim, Hee-Soo Kang, Eon-Sik Lee, Hyoung-Seop Kim
Journal of Korean Powder Metallurgy Institute.2011; 18(5): 406. CrossRef

Microstructure and Tensile Properties of Spray Cast Cu-Sn-Ni-Si Alloy: Hee-Soo Kang, Eon-Sik Lee, Gyu-Chang Lee, Kyeong-Ho Baik; J Korean Powder Metall Inst. 2010;17(6):470-476.; DOI: https://doi.org/10.4150/KPMI.2010.17.6.470

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Abstract PDF: In this study, Cu-10Sn and Cu-10Sn-2Ni-0.2Si alloys have been manufactured by spray casting in order to achieve a fine scale microstructure and high tensile strength, and investigated in terms of microstructural evolution, aging characteristics and tensile properties. Spray cast alloys had a much lower microhardness than continuous cast billet because of an improved homogenization and an extended Sn solid solubility. Spray cast Cu-Sn-Ni-Si alloy was characterized by an equiaxed grain microstructure with a small-sized (Ni, Si)-rich precipitates. Cold rolling of Cu-Sn-Ni-Si alloy increased a tensile strength to 1220 MPa, but subsequent ageing treatment reduced a ultimate tensile strength to 780 MPa with an elongation of 18%.

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