분자동역학 기반 부분 열 접합 된 나노 구리입자들의 인장 및 압축 특성 연구 (Study on Tensile and Compressive Properties of Partially Sintered Nano Copper Particles Based on Molecular Dynamics)

서지정보

· 발행기관 : 한국트라이볼로지학회
· 수록지 정보 : 한국트라이볼로지학회지 / 40권 / 6호 / 181 ~ 188페이지
· 저자명 : 김지완, 황은국, 이태일

초록

In additive manufacturing, understanding the mechanical properties of metal powders is essential to optimize manufacturing processes. This study examines the tensile and compressive characteristics of mono- and polycrystalline copper structures using molecular dynamics simulations. Specifically, we investigate how localized thermal fusion affects the mechanical performance of these copper samples at various energy flux levels and loading conditions. We model hemispherical copper particles to mimic localized sintering effects, with variations in energy absorption resulting in structural transformations, including the face-centered cubic (FCC) to hexagonal close-packed (HCP) phase transition. The first observations indicates that energy absorption enhances the transition from FCC to HCP, initiating at the necking region and propagating at a 45° angle relative to the elongation axis. Additionally, compared to single-crystal structures, polycrystalline structures exhibit more pronounced phase transitions under tensile deformation. Additionally, polycrystalline structures exhibit more pronounced phase transitions under tensile deformation compared to single-crystal structures. Another observations highlight distinct trends in grain boundary generation and growth: single-grain copper samples show grain boundary growth originating from the free surface, while polycrystalline copper samples exhibit newly formed grain boundaries emerging from their initial structures. To quantify the differences between tensile and compressive tests, normalized normal pressure and von Mises stress are evaluated under varying levels of localized energy flux during thermal bonding. This study supports the design and optimization of copper-based additive manufacturing processes by providing useful insights into the microscopic mechanics that govern phase transformations in copper during sintering.

영어초록

In additive manufacturing, understanding the mechanical properties of metal powders is essential to optimize manufacturing processes. This study examines the tensile and compressive characteristics of mono- and polycrystalline copper structures using molecular dynamics simulations. Specifically, we investigate how localized thermal fusion affects the mechanical performance of these copper samples at various energy flux levels and loading conditions. We model hemispherical copper particles to mimic localized sintering effects, with variations in energy absorption resulting in structural transformations, including the face-centered cubic (FCC) to hexagonal close-packed (HCP) phase transition. The first observations indicates that energy absorption enhances the transition from FCC to HCP, initiating at the necking region and propagating at a 45° angle relative to the elongation axis. Additionally, compared to single-crystal structures, polycrystalline structures exhibit more pronounced phase transitions under tensile deformation. Additionally, polycrystalline structures exhibit more pronounced phase transitions under tensile deformation compared to single-crystal structures. Another observations highlight distinct trends in grain boundary generation and growth: single-grain copper samples show grain boundary growth originating from the free surface, while polycrystalline copper samples exhibit newly formed grain boundaries emerging from their initial structures. To quantify the differences between tensile and compressive tests, normalized normal pressure and von Mises stress are evaluated under varying levels of localized energy flux during thermal bonding. This study supports the design and optimization of copper-based additive manufacturing processes by providing useful insights into the microscopic mechanics that govern phase transformations in copper during sintering.

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