|About this Abstract
||2019 TMS Annual Meeting & Exhibition
||Solidification Processing of Light Metals and Alloys: An MPMD Symposium in Honor of David StJohn
||4D Synchrotron Imaging Insights into Grain Formation
||Peter D. Lee, Biao Cai, Mohammad A Azeem, Enyu Guo, David St John
|On-Site Speaker (Planned)
||Peter D. Lee
David St John has performed seminal work on analytic solutions for determining the nucleation free zone, and its impact on grain refining. Using 4D synchrotron imaging (3D plus time), the importance of thermal gradients, nuclei spacing, flow and interaction of neighbouring solute fields was illustrated. In this talk we review how in situ x-ray imaging has helped inform and validate these models, for both grain evolution and also porosity. Results are shown from Diamond Light Source, ESRF and SLS, providing insight into how solute fields interact for alloys ranging from magnesium to nickel superalloys. The results show the dependence of the interactions on both deterministic and stochastic factors. We also show how externally applied fields can dramatically alter the solute fields via induced flow, altering the grain structures.