In situ radiographic study of the grain refining behavior of Al3Sc during the solidification of Al-10Cu alloy

Grain refinement of Al alloys inoculated by rare earth elements, such as Sc, has been extensively acknowledged, while the practical behavior of how inoculant Al3Sc particles affect the refinement in solidification has not been clarified due to the non-transparency of the solidification process. Here, the microstructural evolution of primary Al3Sc particles and alpha-Al grains in Al-10 wt.% Cu alloy solidifications with 0.2 wt.%, 0.6 wt.%, and 1.0 wt.% Sc additions was investigated by in situ synchrotron X-ray radiography. The detailed mechanisms of curve motion of grains (CMG) and melt convection were revealed. The efficient grains nucleation, uniformly scattered small initial grains, and long duration of melt convection contributed to the best refinement in the 0.6 wt.% Sc addition sample. This work provides a deep insight into grain refinement in solidification with Sc addition, which will enlighten the composition design and casting process of Al alloys inoculated by rare earth elements. (C) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

This study investigates the microstructural evolution of Al3Sc particles and alpha-Al grains during solidification using in situ synchrotron X-ray radiography. The best refinement is achieved in the sample with 0.6 wt.% Sc addition, attributed to efficient grain nucleation, uniform distribution of small initial grains, and prolonged melt convection. This research provides valuable insights for the composition design and casting process of Al alloys inoculated with rare earth elements.