|About this Abstract
||2019 TMS Annual Meeting & Exhibition
||Solidification Processing of Light Metals and Alloys: An MPMD Symposium in Honor of David StJohn
||Numerical Modeling of Heterogeneous Nucleation Behavior of Equiaxed Grains during Directional Solidification
||Lang Yuan, David H StJohn, Arvind Prasad, Peter D Lee
|On-Site Speaker (Planned)
The Interdependence model that was proposed by StJohn et al integrates nucleation and growth of equiaxed grains and predicts the nucleation free zone due to the presence of constitutional undercooling ahead of growing dendrites. Recent in-situ synchrotron x-ray experiments confirmed the model prediction and revealed both the solute-suppressed nucleation zone under isothermal solidification environment and the propagation of the nucleation front in directional solidification conditions. The numerical analysis has been carried out for the isothermal conditions in the prior work. In this study, a microscale solidification model which predicts heterogeneous nucleation with the diffusion-controlled dendritic growth are implemented to study the nucleation behavior during directional solidification. The effects of temperature gradient and cooling rate on the nucleation events are investigated to understand the impact of constitutional undercooling. The numerical predictions are then compared with published data from in-situ synchrotron x-ray experiments to provide quantitative insights.