TY - GEN
T1 - Effect of heat treatment on microstructures and mechanical properties of SS316L by micro selective laser melting
AU - Fu, Jin
AU - Qu, Shuo
AU - Ding, Junhao
AU - Song, Xu
AU - Fu, Mingwang
N1 - Funding Information:
Jin FU would like to acknowledge the financial support from The Hong Kong Polytechnic University (NO. 1-ZVMR).
Publisher Copyright:
Copyright © 2021 by ASME
PY - 2021/8
Y1 - 2021/8
N2 - Recently, micro selective laser melting (μSLM) system equipped with finer laser beam has been developed to improve additive manufacturing resolution. The microstructures and properties of μSLM produced metals and alloys could be different from those by conventional-size SLM, which warrants further investigation. Moreover, the widely used material, SS316L stainless steel, demonstrates unique cellular structures and excellent combination of strength and ductility after SLM. How the microstructures evolve after heat treatment and affect the mechanical properties remain to be clarified for μSLMed SS316L. In this study, the effect of heat treatment on the microstructures and mechanical properties of μSLMed SS316L was studied. Two heat treatment methods, namely HT650°C-2h and HT950°C-2h, were employed. It is found that the heat treatment has no effect on phase formation, and a preferred grain growth orientation with (110) plane along building direction and a single austenite phase was detected in all samples. Cellular structures were observed in as-printed samples and found to grow up a little bit after HT650°C-2h, but disappear after HT950°C-2h. Besides, more carbides are detected after HT650°C-2h, while they are partially dissolved after HT950°C-2h. For mechanical properties, the as-printed sample shows the best combination of strength and ductility, thanks to the strengthening effects from cellular structures and dislocations. The inferior mechanical properties after heat treatment is attributed to reduction of dislocations and disappearance of cellular structures. In addition, the presence of carbides can significantly reduce the ductility.
AB - Recently, micro selective laser melting (μSLM) system equipped with finer laser beam has been developed to improve additive manufacturing resolution. The microstructures and properties of μSLM produced metals and alloys could be different from those by conventional-size SLM, which warrants further investigation. Moreover, the widely used material, SS316L stainless steel, demonstrates unique cellular structures and excellent combination of strength and ductility after SLM. How the microstructures evolve after heat treatment and affect the mechanical properties remain to be clarified for μSLMed SS316L. In this study, the effect of heat treatment on the microstructures and mechanical properties of μSLMed SS316L was studied. Two heat treatment methods, namely HT650°C-2h and HT950°C-2h, were employed. It is found that the heat treatment has no effect on phase formation, and a preferred grain growth orientation with (110) plane along building direction and a single austenite phase was detected in all samples. Cellular structures were observed in as-printed samples and found to grow up a little bit after HT650°C-2h, but disappear after HT950°C-2h. Besides, more carbides are detected after HT650°C-2h, while they are partially dissolved after HT950°C-2h. For mechanical properties, the as-printed sample shows the best combination of strength and ductility, thanks to the strengthening effects from cellular structures and dislocations. The inferior mechanical properties after heat treatment is attributed to reduction of dislocations and disappearance of cellular structures. In addition, the presence of carbides can significantly reduce the ductility.
KW - Heat treatment
KW - Mechanical properties
KW - Micro selective laser melting
KW - Microstructures
KW - Stainless steel
UR - http://www.scopus.com/inward/record.url?scp=85112431887&partnerID=8YFLogxK
U2 - 10.1115/MSEC2021-61726
DO - 10.1115/MSEC2021-61726
M3 - Conference article published in proceeding or book
AN - SCOPUS:85112431887
T3 - Proceedings of the ASME 2021 16th International Manufacturing Science and Engineering Conference, MSEC 2021
BT - Additive Manufacturing; Advanced Materials Manufacturing; Biomanufacturing; Life Cycle Engineering; Manufacturing Equipment and Automation
PB - American Society of Mechanical Engineers
T2 - ASME 2021 16th International Manufacturing Science and Engineering Conference, MSEC 2021
Y2 - 21 June 2021 through 25 June 2021
ER -