About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
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Additive Manufacturing: Materials Design and Alloy Development IV: Rapid Development
|
Presentation Title |
J-33: Mechanism of Oxygen-induced Hot Cracking of IN738 during Additive Manufacturing |
Author(s) |
Kenhee Ryou, Boryung Yoo, Pyuck-Pa Choi |
On-Site Speaker (Planned) |
Kenhee Ryou |
Abstract Scope |
Even though IN738 alloy shows notable strength and oxidation resistance behavior in high-temperature among the Ni-based superalloy, hot-cracking behavior resulting from poor weldability is the detrimental factor on the application of additive manufacturing. Usually, a γ-γ' eutectic microstructure with low melting temperature is pointed out as a cause of hot-cracking in the case of Ni-based superalloys. However, we report on a novel hot-cracking mechanism in a direct laser deposited IN738, using joint electron, X-ray, and atom microscopy. The majority of the observed cracks were related to oxides formed in grain interiors and boundaries. Using atom probe tomography, we detected an intermediate zone between oxides and the base alloy, where oxygen existed in solid solution and chemical compositions varied due to the oxide formation. The variation in composition lowered the melting point of the matrix while the oxides promoted stress concentration and crack nucleation, thus causing liquation cracking during reheating. |
Proceedings Inclusion? |
Planned: |
Keywords |
Additive Manufacturing, High-Temperature Materials, Characterization |