| About this Abstract |
| Meeting |
2024 TMS Annual Meeting & Exhibition
|
| Symposium
|
Phase Transformations and Microstructural Evolution
|
| Presentation Title |
Beyond Cooling Rates: Unraveling the Paradox of Finer Grains in Direct Energy Deposition Compared to Powder Bed Fusion |
| Author(s) |
Kaushalendra Singh, Atieh Moridi |
| On-Site Speaker (Planned) |
Kaushalendra Singh |
| Abstract Scope |
The solidification sequence observed for any alloy is directly influenced by the cooling rate associated with the manufacturing process. Within additive manufacturing (AM), the cooling rates vary significantly between processes like Directed Energy Deposition (DED) (103-105 K/s) and powder bed fusion (PBF) (105-107 K/s). These variations in cooling rates can alter the solidification pathways and consequently affect the phase composition as well as the microstructure. In this study, we showcase how these alternative solidification pathways can be leveraged to tune the microstructure of PH 17-4 stainless steel (SS). We provide evidence that challenges conventional wisdom by demonstrating an increased grain size in PBF-printed PH 17-4 SS when compared to DED-printed counterparts. We attribute this increase to the phenomenon of austenitic bypass occurring at cooling rates associated with PBF. Furthermore, we demonstrate that deliberate introduction of austenite-stabilizing nitrogen can be employed to retain metastable austenite and promote grain refinement even when using PBF. |
| Proceedings Inclusion? |
Planned: |