  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.
