Amorphous phase separation in an Fe-based bulk metallic glass

Although lanthanide elements play a critical role in increasing the glass forming ability and mechanical property alternation of Fe based bulk metallic glass (Fe-BMG), the atomic scale configuration of lanthanide in Fe-BMG remained unexplored. Here we have studied atomic configuration in the amorphous state of as-cast 4 mm FeCoCrMoCBY bulk metallic glass sheet and its mechanical properties by nanoindentation, transmission electron microscopy, and atom probe tomography. The current results showed that yttrium rich clusters are enriched with carbon atoms in the amorphous state, and the three dimensional densities of these clusters can influence the hardness at the localized region. The finding of Y-C rich clusters also suggests that the amorphous phase separation can precede the devitrification process. © 2017 Elsevier B.V