Stability of Fe-Based Alloys With Structure Type C₆Cr₂₃

Bulk metallic glass forms when liquid metal alloys solidify without crystallization. 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 carried 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.