Stability of Fe-based alloys with structure type C6Cr23

TL;DR

This study uses first-principles calculations to identify elements like yttrium and rare earths that can destabilize the C6Cr23 crystal structure, potentially improving the glass-forming ability of Fe-based alloys.

Contribution

It introduces a computational approach to predict third elements that destabilize C6Cr23, aiding the design of Fe-based bulk metallic glasses.

Findings

Yttrium effectively destabilizes C6Cr23

Rare earth elements are also suitable

Atomic size influences destabilization effectiveness

Abstract

Bulk metallic glass forms when liquid metal alloys solidify without crystalization. In the search for Iron-based bulk glass-forming alloys of the metal-metalloid type (Fe-B- and Fe-C-based), crystals based on the structural prototype C6Cr23 often preempt the amorphous phase. Destabilizing this competing crystal structure could enhance glass-formability. We carry out first-principles total energy calculations of enthalpy of formation to identify third elements that can effectively destabilize C6Cr23. Yttrium appears optimal among transition metals, and rare earths also are suitable. Atomic size is the dominant factor.