Journal of Powder Materials

Do Won Lee

3 Articles

[English]
Characterization of the Manufacturing Process and Mechanical Properties of CoCrFeMnNi High-Entropy Alloys via Metal Injection Molding and Hot Isostatic Pressing: Eun Seong Kim, Jae Man Park, Do Won Lee, Hyojeong Ha, Jungho Choe, Jaemin Wang, Seong Jin Park, Byeong-Joo Lee, Hyoung Seop Kim; J Powder Mater. 2024;31(3):243-254. Published online June 27, 2024; DOI: https://doi.org/10.4150/jpm.2024.00059

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Abstract PDF: High-entropy alloys (HEAs) have been reported to have better properties than conventional materials; however, they are more expensive due to the high cost of their main components. Therefore, research is needed to reduce manufacturing costs. In this study, CoCrFeMnNi HEAs were prepared using metal injection molding (MIM), which is a powder metallurgy process that involves less material waste than machining process. Although the MIM-processed samples were in the face-centered cubic (FCC) phase, porosity remained after sintering at 1200°C, 1250°C, and 1275°C. In this study, the hot isostatic pressing (HIP) process, which considers both temperature (1150°C) and pressure (150 MPa), was adopted to improve the quality of the MIM samples. Although the hardness of the HIP-treated samples decreased slightly and the Mn composition was significantly reduced, the process effectively eliminated many pores that remained after the 1275°C MIM process. The HIP process can improve the quality of the alloy.

[English]
Fabrication of Equiatomic CoCrFeMnNi High-Entropy Alloy by Metal Injection Molding Process Using Coarse-Sized Powders: Eun Seong Kim, Jae Man Park, Ji Sun Lee, Jungho Choe, Soung Yeoul Ahn, Sang Guk Jeong, Do Won Lee, Seong Jin Park, Hyoung Seop Kim; J Powder Mater. 2023;30(1):1-6. Published online February 1, 2023; DOI: https://doi.org/10.4150/KPMI.2023.30.1.1

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High-entropy alloys (HEAs) are attracting attention because of their excellent properties and functions; however, they are relatively expensive compared with commercial alloys. Therefore, various efforts have been made to reduce the cost of raw materials. In this study, MIM is attempted using coarse equiatomic CoCrFeMnNi HEA powders. The mixing ratio (powder:binder) for HEA feedstock preparation is explored using torque rheometer. The block-shaped green parts are fabricated through a metal injection molding process using feedstock. The thermal debinding conditions are explored by thermogravimetric analysis, and solvent and thermal debinding are performed. It is densified under various sintering conditions considering the melting point of the HEA. The final product, which contains a small amount of non-FCC phase, is manufactured at a sintering temperature of 1250°C.

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Development of 3D interconnected nanoporous TiZrHfNbTaNi high-entropy alloy via liquid metal dealloying and subsequent synthesis of (TiZrHfNbTaNi)O high-entropy oxide
Jae Hyuk Lee, Soo Vin Ha, Jihye Seong, Akira Takeuchi, Ruirui Song, Hidemi Kato, Soo-Hyun Joo
Journal of Materials Research and Technology.2025; 35: 5204. CrossRef
Characterization of the Manufacturing Process and Mechanical Properties of CoCrFeMnNi High-Entropy Alloys via Metal Injection Molding and Hot Isostatic Pressing
Eun Seong Kim, Jae Man Park, Do Won Lee, Hyojeong Ha, Jungho Choe, Jaemin Wang, Seong Jin Park, Byeong-Joo Lee, Hyoung Seop Kim
journal of Korean Powder Metallurgy Institute.2024; 31(3): 243. CrossRef

[English]
Stretch-Flangeability of Laser Powder Bed Fusion-Processed 316L Stainless Steel: Rae Eon Kim, Yeon Taek Choi, Sang Guk Jeong, Do Won Lee, Hyoung Seop Kim; Received January 15, 2025 Accepted April 9, 2025 Published online April 16, 2025; DOI: https://doi.org/10.4150/jpm.2025.00017

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Abstract Supplementary Material: Metal additive manufacturing (AM) facilitates the production of complex geometries with enhanced functionality. Among various AM techniques, laser powder bed fusion (LPBF) is distinguished by its precision and exceptional mechanical properties achieved via laser fusion deposition. Recent advancements in AM have focused on combining LPBF with post-processing methods such as cold rolling, high-pressure torsion, and forming processes. Therefore, understanding the forming behavior of LPBF-processed materials is essential for industrial adoption. This study investigates the stretch-flangeability of LPBF-fabricated 316L stainless steel, emphasizing its anisotropic microstructure and mechanical properties. Hole expansion tests were employed to assess stretch-flangeability in comparison to wrought 316L stainless steel. The results demonstrate that LPBF-processed samples exhibit significant anisotropic behavior, demonstrating the influence of microstructural evolution on formability. These findings contribute valuable insights into optimizing LPBF materials for industrial forming applications.

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