About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
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Symposium
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Additive Manufacturing: Materials Design and Alloy Development IV: Rapid Development
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Presentation Title |
Analysis on Solidification Microstructure and Cracking Mechanism of a Matrix High-speed Steel Deposited by Direct Energy Deposition Process |
Author(s) |
Geon-Woo Park, Sunmi Shin, Byung Jun Kim, Wookjin Lee, Sung Soo Park, Jong Bae Jeon |
On-Site Speaker (Planned) |
Jong Bae Jeon |
Abstract Scope |
We investigated microstructure and cracking mechanism of a matrix high-speed steel fabricated by direct energy deposition. It was attempted to analyze combined effect of rapid solidification and chemical composition on microstructure and cracking mechanism during deposition. Excessive solute segregation into inter-dendritic regions due to rapid solidification gave rise to the formation of retained austenite in the inter-dendritic region and the formation of α'-martensite in the dendritic region, respectively. The excess solute segregation decreased equilibrium solidification temperature and caused precipitation of the low-melting eutectic carbides in the inter-dendritic region. The low-melting eutectic carbides increased hot cracking susceptibility resulting in solidification cracking and liquation cracking in the inter-dendritic region. On the other hand, tensile residual stress in deposited layers generated due to constraint by substrate possibly caused cold cracking in α'-martensite. It was revealed that the cold cracks led to macro-crack growth by connecting the ligaments between hot cracks in deposited layers. |
Proceedings Inclusion? |
Planned: |
Keywords |
Additive Manufacturing, Solidification, Phase Transformations |