The Microstructure Evolution During Rapid Solidification of the Hypereutectic Fe-Based Alloy

Rapidly solidified hypereutectic Fe-based alloy with the chemical composition Fe-3 wt.%C-3wt.%Cr-12wt.%V, was processed by a nitrogen-gas atomization technique. Solidification microstructures were observed using light microscopy, scanning and transmission electron microscopy. X-ray diffraction analysis and Mossbauer spectrometry were used for phase identification and phase quantity measurement, respectively. The structural study of the rapidly solidified powder particles revealed 5 different types of microstructures: microstructure with the globular carbides, microstructure with the star-like carbides, microstructure with primary carbides in the centers of eutectic colonies, microstructure with eutectic colonies without the primary carbides and microstructure with eutectic spherulites. The solidification microstructures were analyzed on the base of the general knowledge of eutectic growth and development of anomalous eutectics in undercooled melts.