| About this Abstract |
| Meeting |
Materials Science & Technology 2020
|
| Symposium
|
Additive Manufacturing Modeling and Simulation: AM Materials, Processes, and Mechanics
|
| Presentation Title |
Transient Evolution of Columnar Dendrites during Additive Manufacturing – Implications for Process Simulations |
| Author(s) |
Bala Radhakrishnan, Younggil Song, Alex Plotkowski, Gerald Knapp, John Turner |
| On-Site Speaker (Planned) |
Bala Radhakrishnan |
| Abstract Scope |
During additive manufacturing of structural alloys, columnar dendritic microstructures are formed under certain temperature gradients (G) and growth rates (R). Whenever a new layer of liquid metal begins to solidify on top of a substrate, formation of a constitutionally undercooled region ahead of the solid-liquid (s-l) interface through solute enrichment to attain a steady-state value of R for a given G, as defined in analytical models, is not attained instantaneously. We demonstrate through phase field simulations in a Ni-Fe-Nb alloy that the non-steady state portion of the evolution could become significant enough to introduce potential errors when a steady state approximation is assumed in simulating the microstructure evolution. The implications for predictive processing-microstructure simulations during additive manufacturing are discussed. Research supported by the Department of Energy's Exascale Computing project at the Oak Ridge National Laboratory under contract DE-AC05-00OR22725. The simulations were performed using the Oak Ridge Leadership Class computing facilities. |