  We investigate short rane order in liquid and supercooled liquid Fe and
Fe-based metallic glass using ab-initio simulation methods. We analyze the data
to quantify the degree of local icosahedral and polytetrahedral order and to
understand the role of alloying in controlling the degree of geometric
frustration . Comparing elemental Fe to Cu we find that the degree of
icosahedral order is greater in Fe than in Cu, possibly because icosahedral
disclination line defects are more easily incorporated into BCC environments
than FCC. In Fe-based metallic glass-forming alloys (FeB and FeZrB) we find
that introducing small concentrations of small B atoms and large Zr atoms
controls the frustration of local icosahedral order.
