3D morphological evolution and growth mechanism of proeutectic FeAl3 phases formed at Al/Fe interface under different cooling rates

The 3D morphologies and growth mechanisms of proeutectic FeAl 3 at the Al/Fe interface under different cooling rates were studied by synchrotron X-ray tomography. With increasing cooling rate, FeAl 3 crystals developed from faceted polygonal prism, plates with flat surface, thin ribbon-like with periodic undulating surface to non-faceted rods with radial dendrites in cross section, indicating a gradual interface growth mode transition from two-dimensional layer growth to continuous growth. At a higher cooling rate, twinning mechanism plays a leading role in the formation and growth of FeAl 3 . A link between the morphologies, twinning and crystallographic structure was established based on quantitative analyses on the 3D structures. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

This study investigated the three-dimensional morphologies and growth mechanisms of proeutectic FeAl3 at the Al/Fe interface under different cooling rates using synchrotron X-ray tomography. The results showed that the morphology and growth mechanism of FeAl3 crystals changed with increasing cooling rate, transitioning from faceted polygonal prism to non-faceted rods with radial dendrites in cross section. Furthermore, twinning mechanism was found to play a dominant role in the formation and growth of FeAl3 at higher cooling rates.