|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Frontiers in Solidification: An MPMD Symposium in Honor of Michel Rappaz
||QQ-9: Computer Simulation of Freckle Formation Using a Three-Dimensional Micro-scale Model
||Mohammad Hashemi, Mohsen Eshraghi, Sergio D. Felicelli
|On-Site Speaker (Planned)
The channel-like micro-segregation defects which form during directional solidification of metallic alloys can significantly degrade the mechanical properties of cast products. Studies have shown that the density inversion drives the motion of high solute composition liquid between the dendrites that ultimately advects out of the mushy zone and emerges as a plume. When the channels completely solidify, they form the freckle defects. Although experimental studies and continuum-type models have attempted to investigate this phenomenon, micro-scale computer simulations have scarcely been done and they can provide a more comprehensive detailed picture of freckle formation. A three-dimensional numerical model is developed in order to better understand the buoyancy-induced mechanism of freckling. The model integrates lattice Boltzmann method and cellular automaton as two local structure methods to improve the computational efficiency and provide scalability over multiple computing cores. The model is used to study freckling during directional solidification of binary alloys.