|About this Abstract
||2019 TMS Annual Meeting & Exhibition
||Solidification Processing of Light Metals and Alloys: An MPMD Symposium in Honor of David StJohn
||X-Ray Synchrotron Radiography Investigations of Primary and Secondary Phase Nucleation in Aluminium Alloys
||Enzo Liotti, Andrew Lui , Patrick S. Grant
|On-Site Speaker (Planned)
||Patrick S. Grant
Laboratory and synchrotron X-rays are used routinely for the study of metallic alloy solidification by radiography and tomography. The majority of studies concern crystal growth, such as crystal shape and morphological stability. In contrast, and despite practical experience showing nucleation plays a critical role in final structure and properties, crystal nucleation has received less attention because experiments to observe nucleation in liquid metals are difficult. Nonetheless, insightful nucleation theory has been developed since the 1950s, much of which is validated only implicitly by post-solidification microscopy. We present a comprehensive study of the dynamics of primary and secondary phase formation in aluminium alloys using latest developments in automated computer vision, machine learning and X-ray detector science, including measurement of undercoolings and nucleation bursts. Inspired by the work of StJohn and co-workers, we show the importance of ensemble solute interactions due to existing crystals with the nucleation behaviour of new crystals.