| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Progress towards Understanding the Synthesis and Behavior of Metals Far from Equilibrium: A SMD Symposium Honoring Enrique Lavernia on the Occasion of His 60th Birthday
|
| Presentation Title |
Microstructure of Additively Manufactured and Laser Melted 316L Stainless Steel |
| Author(s) |
Thomas M. Devine, Yoon Hwa, Joshua K. Yee, Nancy Y Yang |
| On-Site Speaker (Planned) |
Yoon Hwa |
| Abstract Scope |
The microstructure of laser melted 316L stainless steel is investigated as a function of laser power density, laser translation speed, and ambient gas flow. Samples were formed by additive manufacturing (LENS) of powders and by surface melting of a solid plate. In both types of samples, the optical microstructures are similar and are inhomogeneous on the scale of several microns. Two aspects of the inhomogeneous microstructures stand out. First, the mode of solidification changes from plane front to cellular with increasing distance from the fusion line. Second, banding occurs across the entire cross-section of the LENS hatch and across the cross-section of the surface melted tracks and of surface melted spots. Changes in solidification mode are associated with the spatial variation of the ratio of thermal gradient to solidification velocity. Banding is caused by high laser power and ambient gas flow. A mechanism of banding is proposed. |
| Proceedings Inclusion? |
Undecided |