In this study, effect of core-shell structure on compaction behavior of harmonic powder is investigated. Harmonic powders are made by electroless plating method on Fe powders. Softer Cu shell encloses harder Fe core, and the average size of Fe core and thickness of Cu shell are 34.3 μm and 3.2 μm, respectively. The powder compaction procedure is processed with pressure of 600 MPa in a cylindrical die. Due to the low strength of Cu shell regions, the harmonic powders show better densification behavior compared with pure Fe powders. Finite element method (FEM) is performed to understand the roll of core-shell structure. Based on stress and strain distributions of FEM results, it is concluded that the early stage of powder compaction of harmonic powders mainly occurs at the shell region. FEM results also well predict porosity of compacted materials.

Abstract
 1. 서 론
 2. 실험방법
 3. 결과 및 고찰
 4. 결 론

• 주수현(포항공과대학교 항공재료연구센터) | Soo-Hyun Joo
• 박효욱(포항공과대학교 신소재공학과) | Hyo Wook Park
• 강수영(인하공업전문대학 금속재료과) | Soo Young Kang
• 이언식(포항산업과학연구원 재료공정연구소) | Eon Sik Lee
• 강희수(포항산업과학연구원 재료공정연구소) | Hee-Soo Kang
• 김형섭(포항공과대학교 항공재료연구센터, 포항공과대학교 신소재공학과) | Hyong Seop Kim Corresponding author