| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Additive Manufacturing: Processing Effects on Microstructure and Material Performance
|
| Presentation Title |
Origin of Dislocation Structures in Additively Manufactured Austenitic Stainless Steel |
| Author(s) |
Kaila Morgen Bertsch, Gabriel Meric de Bellefon, Bailey Kuehl, Dan Thoma |
| On-Site Speaker (Planned) |
Kaila Morgen Bertsch |
| Abstract Scope |
Additively manufactured (AM) stainless steels exhibit hierarchical, chemically inhomogeneous dislocation microstructures, but their exact origins are not fully understood. In this study, the physical origins of AM dislocation structures were investigated by isolating the effects of thermal distortions on the microstructure. “1D” rods, “2D” walls, and 3D geometries were fabricated with directed energy deposition (DED) and selective laser melting (SLM) of 316L such that thermal cooling and expansion were less constrained in parts with lower dimensions. The influences of dendritic segregation, misorientations between dendrites, and geometric constraints on dislocation structure formation were evaluated via SEM, transmission EBSD, S/TEM, and EDS. Dislocation density increased with increasing geometric constraints, increasing by an order of magnitude with each additional dimension in DED parts. Dislocations were found to originate due to thermal stresses, and the interaction between mobile dislocations and solute-rich interdendritic regions dictate the crystallography and scale of the final microstructure. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |