| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
|
Additive Manufacturing: Microstructure, Defects, and Properties
|
| Presentation Title |
A Mechanistic Explanation for Shrinkage Porosity in Laser Powder Bed Fusion Alloy 718 |
| Author(s) |
William J. Frieden Templeton, Shawn Hinnebusch, Seth T. Strayer, Albert C. To, P. Chris Pistorius, Sneha P. Narra |
| On-Site Speaker (Planned) |
William J. Frieden Templeton |
| Abstract Scope |
This work focuses on the occurrence of shrinkage porosity and its manifestation in Alloy 718 during laser-powder bed fusion (PBF-LB) processing. This work employs microstructure characterization and an analytical heat transfer model to develop a mechanistic explanation for the formation of shrinkage porosity in the PBF-LB process. The results show the formation of shrinkage porosity can be predicted using heuristic based on secondary dendrite arm spacing, where changes in the microstructure at high cooling rates during solidification mitigate porosity. For practical use, shrinkage porosity process maps are presented for use in process design and control to directly aid shrinkage pore mitigation in process planning. The process-shrinkage porosity relationship results also indicate that trends in PBF-LB manufacturing toward higher deposition temperatures and higher throughput are likely to aggravate the conditions for shrinkage pore formation and further elevate the importance of the mitigation strategies presented in this work. |