About this Abstract |
| Meeting |
MS&T25: Materials Science & Technology
|
| Symposium
|
Additive Manufacturing Modeling, Simulation, and Machine Learning: Microstructure, Mechanics, and Process
|
| Presentation Title |
Microstructure Design Using Kinetic Model of the ä-Ferrite to ã-Austenite Phase Transformation in 17-4 PH Stainless Steel LPBF |
| Author(s) |
Sohee An, Seung-Ho Lee, Jongcheon Yoon, Il Sohn, Kyunsuk Choi, Du-Rim Eo |
| On-Site Speaker (Planned) |
Du-Rim Eo |
| Abstract Scope |
17-4 Precipitation-hardened (PH) stainless steels fabricated through laser powder bed fusion (LPBF) retain δ-ferrite due to the rapid cooling rates of up to 107 K/s. Some of δ-ferrite transforms into γ-austenite, which subsequently transitions to α’-martensite under sufficient cooling rates. This process results in a final microstructure comprising δ-ferrite, α’-martensite, and retained austenite. The cooling rate, controlled by the volumetric energy density (VED), and the alloy composition, particularly the Creq/Nieq ratio, are critical in determining the final microstructure. This study shows how we can predicts and control the final microstructure by combining numerical calculations for the δ-to-γ phase transformation based on classical nucleation and grain growth theories with simulated thermal history profiles. The predicted microstructures were validated by comparing them with experimentally observed results, demonstrating high accuracy. |