|About this Abstract
||Materials Science & Technology 2020
||Phase Transformations in Additively Manufactured Materials
||Phase Field Simulations of Cellular-to-Dendritic Transition under Additive Manufacturing Conditions
||Younggil Song, Steve DeWitt, Bala Radhakrishnan, John A. Turner
|On-Site Speaker (Planned)
Columnar dendritic microstructures are often observed during solidification of structural alloys under additive manufacturing conditions. We present large scale, high-resolution, three-dimensional, phase field simulations of the evolution of an initially flat solid-liquid interface into a cellular structure, growth competition between cells, and the initiation of the cellular to dendritic transformation (CDT) in a ternary Ni-Fe-Nb alloy that serves as a surrogate for the nickel-base superalloy 718. The simulations capture the effect of the temperature gradient and the solid-liquid interface velocity on the critical cell spacing above which CDT occurs. The mechanism by which the dendritic sidebranches emerge and grow will be examined through characterization of the evolution of the cell morphology and the solute concentration fields at the vicinity of the cell tip. Research performed at ORNL under contract DE-AC05-00OR22725 and supported by the Department of Energy’s Exascale Computing Project and the Oak Ridge Leadership Class Computing Facilities.