Speaker
Description
During solidification processing of metals and alloys, buoyant flow of thermal and/or solutal origin is known to significantly affect microstructure selection. Here, we use a multiscale Dendritic Needle Network (DNN) model for directional solidification with buoyant liquid flow, in order to study the effect of gravity on the growth dynamics of dendritic arrays. First, we compare our simulation results to time-resolved x-ray imaging of thin-sample directional solidification experiments performed on Sn-Bi alloys [1], in order to highlight the differences between hydrodynamically stable and unstable regimes as a function of the growth direction with respect to gravity. Then, we focus on the unstable regime leading to oscillatory dendritic growth velocities, as recently reported in directional solidification of nickel-based superalloys [2]. On the basis of our simulations, we provide insight into the underlying mechanisms of this oscillatory regime, with the aim to further our understanding and capacity to produce defect-free single-crystal superalloys.
[1] J.W. Gibbs et al., JOM 68 (2016) 170-177
[2] G. Reinhart, et al., Acta Materialia 194 (2020) 68-79
| Speaker Country | Spain |
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