|About this Abstract
||Materials Science & Technology 2020
||Additive Manufacturing Modeling and Simulation: AM Materials, Processes, and Mechanics
||Transient Evolution of Columnar Dendrites during Additive Manufacturing – Implications for Process Simulations
||Bala Radhakrishnan, Younggil Song, Alex Plotkowski, Gerald Knapp, John Turner
|On-Site Speaker (Planned)
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.
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