|학술대회||2018년 가을 (11/07 ~ 11/09, 여수 디오션리조트)|
|발표분야||D. 구조 재료 분과|
|제목||Microstructures of SUS 316L and SUS 439 Products Fabricated by Different Laser Patterns of Selective Laser Manufacturing Process|
|초록||Additive manufacturing (AM) is a relatively new manufacturing technology. Selective laser sintering (SLS) is a type of AM that produces objects from metal powder deposited in a thin layer by selective laser scanning. SLS can produce fully dense parts of complex geometry objects. It becomes a promising technique in the automotive, aerospace, and medical fields, where the unique design is required.
In this study, austenitic (316L) and ferritic (439) steel samples were manufactured by selective laser sintering process. The samples were designed in cube shape and built on the substrate of steel with various parameters of the sintering system. Microstructure and mechanical properties of the sintered samples were investigated. It was found that the intense localized heating, non-uniform and asymmetric temperature gradients and subsequently fast cooling introduces unique high level structural hierarchies and micro-structure heterogeneities in laser melted steel parts. A unique structural hierarchy from the millimetre scale melt pools down to the sub-micron or nano scale cellular sub-grains was observed. The cellular sub-grains were about 1μm in as-built 316L sample. The hierarchical structure could also be seen in the as-built 439 sample but there was no sign of cellular or columnar sub-grains. Instead of that, a macro-textured chessboard structure at macro scale with the boundaries recrystallized grains with much smaller size.
ACKNOWLEDGEMENTS: 이 논문은 2018년도 정부(미래창조과학부)의 재원으로 한국연구재단의 지원을 받아 수행된 지역신산업선도인력양성사업 성과임
|저자||김진천, 유승민, Minh-Thuyet Nguyen1, Dac-Phuc Chu, 김진형, 이동완|
|키워드||Additive manufacturing; 316L steel; 439 steel; microstructure; mechanical properties|